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Formation A fire whirl consists of a burning core and a rotating pocket of air. A fire whirl can reach up to 2,000 °F (1,090 °C). Fire whirls become frequent when a wildfire, or especially firestorm, creates its own wind, which can spawn large vortices. Even bonfires often have whirls on a smaller scale and tiny fire whirls have been generated by very small fires in laboratories.Most of the largest fire whirls are spawned from wildfires. They form when a warm updraft and convergence from the wildfire are present. They are usually 10–50 m (33–164 ft) tall, a few meters (several feet) wide, and last only a few minutes. Some, however, can be more than 1 km (0.6 mi) tall, contain wind speeds over 200 km/h (120 mph), and persist for more than 20 minutes.Fire whirls can uproot trees that are 15 m (49 ft) tall or more. These can also aid the 'spotting' ability of wildfires to propagate and start new fires as they lift burning materials such as tree bark. These burning embers can be blown away from the fire-ground by the stronger winds aloft. Fire whirls can be common within the vicinity of a plume during a volcanic eruption. These range from small to large and form from a variety of mechanisms, including those akin to typical fire whirl processes, but can result in Cumulonimbus flammagenitus (cloud) spawning landspouts and waterspouts or even to develop mesocyclone-like updraft rotation of the plume itself and/or of the cumulonimbi, which can spawn tornadoes similar to those in supercells. Pyrocumulonimbi generated by large fires on rare occasion also develops in a similar way.Notable examples During the 1871 Peshtigo fire, the community of Williamsonville, Wisconsin, was burned by a fire whirl; the area where Williamsonville once stood is now Tornado Memorial County Park.An extreme example of a fire whirl is the 1923 Great Kantō earthquake in Japan, which ignited a large city-sized firestorm which in turn produced a gigantic fire whirl that killed 38,000 people in fifteen minutes in the Hifukusho-Ato region of Tokyo.Numerous large fire whirls (some tornadic) that developed after lightning struck an oil storage facility near San Luis Obispo, California, on 7 April 1926, produced significant structural damage well away from the fire, killing two. Many whirlwinds were produced by the four-day-long firestorm coincident with conditions that produced severe thunderstorms, in which the larger fire whirls carried debris 5 km (3.1 mi) away.Fire whirls were produced in the conflagrations and firestorms triggered by firebombings of European and Japanese cities during World War II and by the atomic bombings of Hiroshima and Nagasaki. Fire whirls associated with the bombing of Hamburg, particularly those of 27–28 July 1943, were studied.Throughout the 1960s and 1970s, particularly in 1978–1979, fire whirls ranging from the transient and very small to intense, long-lived tornado-like vortices capable of causing significant damage were spawned by fires generated from the 1000 MW Météotron, a series of large oil wells located in the Lannemezan plain of France used for testing atmospheric motions and thermodynamics.During the 2003 Canberra bushfires in Canberra, Australia, a violent fire whirl was documented. It was calculated to have horizontal winds of 160 mph (260 km/h) and vertical air speed of 93 mph (150 km/h), causing the flashover of 300 acres (120 ha) in 0.04 seconds. It was the first known fire whirl in Australia to have EF3 wind speeds on the Enhanced Fujita scale.A fire whirl, of reportedly uncommon size for New Zealand wildfires, formed on day three of the 2017 Port Hills fires in Christchurch. Pilots estimated the fire column to be 100 m (330 ft) high.Residents in the city of Redding, California, while evacuating the area from the massive Carr Fire in late July 2018, reported seeing pyrocumulonimbus clouds and tornado-like behaviour from the firestorm, resulting in uprooted trees, cars, structures and other wind related damages in addition to the fire itself. As of August 2, 2018, a preliminary damage survey, led by the National Weather Service (NWS) in Sacramento, California, rated the July 26th fire whirl as an EF3 tornado with winds in excess of 143 mph (230 km/h).On August 15, 2020, for the first time in its history, the U.S. National Weather Service issued a tornado warning for a pyrocumulonimbus created by a wildfire near Loyalton, California, capable of producing a fire tornado.

Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition. In the automotive industry, handling and braking are the major components of a vehicle's "active" safety, as well as its ability to perform in auto racing. The maximum lateral acceleration is sometimes discussed separately as "road holding". (This discussion is directed at road vehicles with at least three wheels, but some of it may apply to other ground vehicles). Automobiles driven on public roads whose engineering requirements emphasize handling over comfort and passenger space are named sports cars.

Track and wheelbase The axle track provides the resistance to lateral weight transfer and body lean. The wheelbase provides resistance to longitudinal weight transfer and to pitch angular inertia, and provides the torque lever arm to rotate the car when swerving. The wheelbase, however, is less important than angular inertia (polar moment) to the vehicle's ability to swerve quickly. The wheelbase contributes to the vehicle's turning radius, which is also a handling characteristic.

Yaw and pitch angular inertia (polar moment) Unless the vehicle is very short, compared to its height or width, these are about equal. Angular inertia determines the rotational inertia of an object for a given rate of rotation. The yaw angular inertia tends to keep the direction the car is pointing changing at a constant rate. This makes it slower to swerve or go into a tight curve, and it also makes it slower to turn straight again. The pitch angular inertia detracts from the ability of the suspension to keep front and back tire loadings constant on uneven surfaces and therefore contributes to bump steer. Angular inertia is an integral over the square of the distance from the center of gravity, so it favors small cars even though the lever arms (wheelbase and track) also increase with scale. (Since cars have reasonable symmetrical shapes, the off-diagonal terms of the angular inertia tensor can usually be ignored.) Mass near the ends of a car can be avoided, without re-designing it to be shorter, by the use of light materials for bumpers and fenders or by deleting them entirely. If most of the weight is in the middle of the car then the vehicle will be easier to spin, and therefore will react quicker to a turn.Track and wheelbase The axle track provides the resistance to lateral weight transfer and body lean. The wheelbase provides resistance to longitudinal weight transfer and to pitch angular inertia, and provides the torque lever arm to rotate the car when swerving. The wheelbase, however, is less important than angular inertia (polar moment) to the vehicle's ability to swerve quickly. The wheelbase contributes to the vehicle's turning radius, which is also a handling characteristic.

Centre of mass In steady-state cornering, front-heavy cars tend to understeer and rear-heavy cars to oversteer (Understeer & Oversteer explained), all other things being equal. The mid-engine design seeks to achieve the ideal center of mass, though front-engine design has the advantage of permitting a more practical engine-passenger-baggage layout. All other parameters being equal, at the hands of an expert driver a neutrally balanced mid-engine car can corner faster, but a FR (front-engined, rear-wheel drive) layout car is easier to drive at the limit. The rearward weight bias preferred by sports and racing cars results from handling effects during the transition from straight-ahead to cornering. During corner entry the front tires, in addition to generating part of the lateral force required to accelerate the car's centre of mass into the turn, also generate a torque about the car's vertical axis that starts the car rotating into the turn. However, the lateral force being generated by the rear tires is acting in the opposite torsional sense, trying to rotate the car out of the turn. For this reason, a car with "50/50" weight distribution will understeer on initial corner entry. To avoid this problem, sports and racing cars often have a more rearward weight distribution. In the case of pure racing cars, this is typically between "40/60" and "35/65". This gives the front tires an advantage in overcoming the car's moment of inertia (yaw angular inertia), thus reducing corner-entry understeer. Using wheels and tires of different sizes (proportional to the weight carried by each end) is a lever automakers can use to fine tune the resulting over/understeer characteristics.

Rigidity of the frame The frame may flex with load, especially twisting on bumps. Rigidity is considered to help handling. At least it simplifies the suspension engineers work. Some cars, such as the Mercedes-Benz 300SL have had high doors to allow a stiffer frame.Driver handling the car Handling is a property of the car, but different characteristics will work well with different drivers.

Rigidity of the frame The frame may flex with load, especially twisting on bumps. Rigidity is considered to help handling. At least it simplifies the suspension engineers work. Some cars, such as the Mercedes-Benz 300SL have had high doors to allow a stiffer frame.

Electronic stability control Electronic stability control (ESC) is a computerized technology that improves the safety of a vehicle's stability by attempting to detect and prevent skids. When ESC detects loss of steering control, the system applies individual brakes to help "steer" the vehicle where the driver wants to go. Braking is automatically applied to individual wheels, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer. The stability control of some cars may not be compatible with some driving techniques, such as power induced over-steer. It is therefore, at least from a sporting point of view, preferable that it can be disabled.

Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition. In the automotive industry, handling and braking are the major components of a vehicle's "active" safety, as well as its ability to perform in auto racing. The maximum lateral acceleration is sometimes discussed separately as "road holding". (This discussion is directed at road vehicles with at least three wheels, but some of it may apply to other ground vehicles). Automobiles driven on public roads whose engineering requirements emphasize handling over comfort and passenger space are named sports cars.Steering Depending on the driver, steering force and transmission of road forces back to the steering wheel and the steering ratio of turns of the steering wheel to turns of the road wheels affect control and awareness. Play—free rotation of the steering wheel before the wheels rotate—is a common problem, especially in older model and worn cars. Another is friction. Rack and pinion steering is generally considered the best type of mechanism for control effectiveness. The linkage also contributes play and friction. Caster—offset of the steering axis from the contact patch—provides some of the self-centering tendency. Precision of the steering is particularly important on ice or hard packed snow where the slip angle at the limit of adhesion is smaller than on dry roads. The steering effort depends on the downward force on the steering tires and on the radius of the contact patch. So for constant tire pressure, it goes like the 1.5 power of the vehicle's weight. The driver's ability to exert torque on the wheel scales similarly with his size. The wheels must be rotated farther on a longer car to turn with a given radius. Power steering reduces the required force at the expense of feel. It is useful, mostly in parking, when the weight of a front-heavy vehicle exceeds about ten or fifteen times the driver's weight, for physically impaired drivers and when there is much friction in the steering mechanism. Four-wheel steering has begun to be used on road cars (Some WW II reconnaissance vehicles had it). It relieves the effect of angular inertia by starting the whole car moving before it rotates toward the desired direction. It can also be used, in the other direction, to reduce the turning radius. Some cars will do one or the other, depending on the speed. Steering geometry changes due to bumps in the road may cause the front wheels to steer in different directions together or independent of each other. The steering linkage should be designed to minimize this effect.Familiarity The more experience a person has with a car or type of car the more likely they will be to take full advantage of its handling characteristics under adverse conditions.Position and support for the driver Having to withstand "g forces" in his/her arms interferes with a driver's precise steering. In a similar manner, a lack of support for the seating position of the driver may cause them to move around as the car undergoes rapid acceleration (through cornering, taking off or braking). This interferes with precise control inputs, making the car more difficult to control. Being able to reach the controls easily is also an important consideration, especially if a car is being driven hard. In some circumstances, good support may allow a driver to retain some control, even after a minor accident or after the first stage of an accident.External conditions that affect handling Weather Weather affects handling by changing the amount of available traction on a surface. Different tires do best in different weather. Deep water is an exception to the rule that wider tires improve road holding. (See aquaplaning under tires, below.)Road condition Cars with relatively soft suspension and with low unsprung weight are least affected by uneven surfaces, while on flat smooth surfaces the stiffer the better. Unexpected water, ice, oil, etc. are hazards.Understeer – the front wheels tend to crawl slightly or even slip and drift towards the outside of the turn. The driver can compensate by turning a little more tightly, but road-holding is reduced, the car's behaviour is less predictable and the tires are liable to wear more quickly. Oversteer – the rear wheels tend to crawl or slip towards the outside of the turn more than the front. The driver must correct by steering away from the corner, otherwise the car is liable to spin, if pushed to its limit. Oversteer is sometimes useful, to assist in steering, especially if it occurs only when the driver chooses it by applying power. Bump steer – the effect of irregularity of a road surface on the angle or motion of a car. It may be the result of the kinematic motion of the suspension rising or falling, causing toe-in or toe-out at the loaded wheel, ultimately affecting the yaw angle (heading) of the car. It may also be caused by defective or worn out suspension components. This will always happen under some conditions but depends on suspension, steering linkage, unsprung weight, angular inertia, differential type, frame rigidity, tires and tire pressures. If suspension travel is exhausted the wheel either bottoms or loses contact with the road. As with hard turning on flat roads, it is better if the wheel picks up by the spring reaching its neutral shape, rather than by suddenly contacting a limiting structure of the suspension. Body roll – the car leans towards the outside of the curve. This interferes with the driver's control, because they must wait for the car to finish leaning before they can fully judge the effect of his steering change. It also adds to the delay before the car moves in the desired direction. It also slightly changes the weight borne by the tires as described in weight transfer. Excessive load transfer – On any vehicle that is cornering, the outside wheels are more heavily loaded than the inside due to the CG being above the ground. Total weight transfer (sum of front and back), in steady cornering, is determined by the ratio of the height of a car's center of gravity to its axle track. When the weight transfer equals half the vehicle's loaded weight, it will start to roll over. This can be avoided by manually or automatically reducing the turn rate, but this causes further reduction in road-holding. Slow response – sideways acceleration does not start immediately when the steering is turned and may not stop immediately when it is returned to center. This is partly caused by body roll. Other causes include tires with high slip angle, and yaw and roll angular inertia. Roll angular inertia aggravates body roll by delaying it. Soft tires aggravate yaw angular inertia by waiting for the car to reach their slip angle before turning the car.

Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition. In the automotive industry, handling and braking are the major components of a vehicle's "active" safety, as well as its ability to perform in auto racing. The maximum lateral acceleration is sometimes discussed separately as "road holding". (This discussion is directed at road vehicles with at least three wheels, but some of it may apply to other ground vehicles). Automobiles driven on public roads whose engineering requirements emphasize handling over comfort and passenger space are named sports cars.

Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition. In the automotive industry, handling and braking are the major components of a vehicle's "active" safety, as well as its ability to perform in auto racing. The maximum lateral acceleration is sometimes discussed separately as "road holding". (This discussion is directed at road vehicles with at least three wheels, but some of it may apply to other ground vehicles). Automobiles driven on public roads whose engineering requirements emphasize handling over comfort and passenger space are named sports cars.Centre of mass In steady-state cornering, front-heavy cars tend to understeer and rear-heavy cars to oversteer (Understeer & Oversteer explained), all other things being equal. The mid-engine design seeks to achieve the ideal center of mass, though front-engine design has the advantage of permitting a more practical engine-passenger-baggage layout. All other parameters being equal, at the hands of an expert driver a neutrally balanced mid-engine car can corner faster, but a FR (front-engined, rear-wheel drive) layout car is easier to drive at the limit. The rearward weight bias preferred by sports and racing cars results from handling effects during the transition from straight-ahead to cornering. During corner entry the front tires, in addition to generating part of the lateral force required to accelerate the car's centre of mass into the turn, also generate a torque about the car's vertical axis that starts the car rotating into the turn. However, the lateral force being generated by the rear tires is acting in the opposite torsional sense, trying to rotate the car out of the turn. For this reason, a car with "50/50" weight distribution will understeer on initial corner entry. To avoid this problem, sports and racing cars often have a more rearward weight distribution. In the case of pure racing cars, this is typically between "40/60" and "35/65". This gives the front tires an advantage in overcoming the car's moment of inertia (yaw angular inertia), thus reducing corner-entry understeer. Using wheels and tires of different sizes (proportional to the weight carried by each end) is a lever automakers can use to fine tune the resulting over/understeer characteristics.Track and wheelbase The axle track provides the resistance to lateral weight transfer and body lean. The wheelbase provides resistance to longitudinal weight transfer and to pitch angular inertia, and provides the torque lever arm to rotate the car when swerving. The wheelbase, however, is less important than angular inertia (polar moment) to the vehicle's ability to swerve quickly. The wheelbase contributes to the vehicle's turning radius, which is also a handling characteristic.Static alignment of the wheels Of course things should be the same, left and right, for road cars. Camber affects steering because a tire generates a force towards the side that the top is leaning towards. This is called camber thrust. Additional front negative camber is used to improve the cornering ability of cars with insufficient camber gain.Understeer – the front wheels tend to crawl slightly or even slip and drift towards the outside of the turn. The driver can compensate by turning a little more tightly, but road-holding is reduced, the car's behaviour is less predictable and the tires are liable to wear more quickly. Oversteer – the rear wheels tend to crawl or slip towards the outside of the turn more than the front. The driver must correct by steering away from the corner, otherwise the car is liable to spin, if pushed to its limit. Oversteer is sometimes useful, to assist in steering, especially if it occurs only when the driver chooses it by applying power. Bump steer – the effect of irregularity of a road surface on the angle or motion of a car. It may be the result of the kinematic motion of the suspension rising or falling, causing toe-in or toe-out at the loaded wheel, ultimately affecting the yaw angle (heading) of the car. It may also be caused by defective or worn out suspension components. This will always happen under some conditions but depends on suspension, steering linkage, unsprung weight, angular inertia, differential type, frame rigidity, tires and tire pressures. If suspension travel is exhausted the wheel either bottoms or loses contact with the road. As with hard turning on flat roads, it is better if the wheel picks up by the spring reaching its neutral shape, rather than by suddenly contacting a limiting structure of the suspension. Body roll – the car leans towards the outside of the curve. This interferes with the driver's control, because they must wait for the car to finish leaning before they can fully judge the effect of his steering change. It also adds to the delay before the car moves in the desired direction. It also slightly changes the weight borne by the tires as described in weight transfer. Excessive load transfer – On any vehicle that is cornering, the outside wheels are more heavily loaded than the inside due to the CG being above the ground. Total weight transfer (sum of front and back), in steady cornering, is determined by the ratio of the height of a car's center of gravity to its axle track. When the weight transfer equals half the vehicle's loaded weight, it will start to roll over. This can be avoided by manually or automatically reducing the turn rate, but this causes further reduction in road-holding. Slow response – sideways acceleration does not start immediately when the steering is turned and may not stop immediately when it is returned to center. This is partly caused by body roll. Other causes include tires with high slip angle, and yaw and roll angular inertia. Roll angular inertia aggravates body roll by delaying it. Soft tires aggravate yaw angular inertia by waiting for the car to reach their slip angle before turning the car.

Unsprung weight Ignoring the flexing of other components, a car can be modeled as the sprung weight, carried by the springs, carried by the unsprung weight, carried by the tires, carried by the road. Unsprung weight is more properly regarded as a mass which has its own inherent inertia separate from the rest of the vehicle. When a wheel is pushed upwards by a bump in the road, the inertia of the wheel will cause it to be carried further upward above the height of the bump. If the force of the push is sufficiently large, the inertia of the wheel will cause the tire to completely lift off the road surface resulting in a loss of traction and control. Similarly when crossing into a sudden ground depression, the inertia of the wheel slows the rate at which it descends. If the wheel inertia is large enough, the wheel may be temporarily separated from the road surface before it has descended back into contact with the road surface. This unsprung weight is cushioned from uneven road surfaces only by the compressive resilience of the tire (and wire wheels if fitted), which aids the wheel in remaining in contact with the road surface when the wheel inertia prevents close-following of the ground surface. However, the compressive resilience of the tire results in rolling resistance which requires additional kinetic energy to overcome, and the rolling resistance is expended in the tire as heat due to the flexing of the rubber and steel bands in the sidewalls of the tires. To reduce rolling resistance for improved fuel economy and to avoid overheating and failure of tires at high speed, tires are designed to have limited internal damping. So the "wheel bounce" due to wheel inertia, or resonant motion of the unsprung weight moving up and down on the springiness of the tire, is only poorly damped, mainly by the dampers or shock absorbers of the suspension. For these reasons, high unsprung weight reduces road holding and increases unpredictable changes in direction on rough surfaces (as well as degrading ride comfort and increasing mechanical loads). This unsprung weight includes the wheels and tires, usually the brakes, plus some percentage of the suspension, depending on how much of the suspension moves with the body and how much with the wheels; for instance a solid axle suspension is completely unsprung. The main factors that improve unsprung weight are a sprung differential (as opposed to live axle) and inboard brakes. (The De Dion tube suspension operates much as a live axle does, but represents an improvement because the differential is mounted to the body, thereby reducing the unsprung weight.) Wheel materials and sizes will also have an effect. Aluminium alloy wheels are common due to their weight characteristics which help to reduce unsprung mass. Magnesium alloy wheels are even lighter but corrode easily. Since only the brakes on the driving wheels can easily be inboard, the Citroën 2CV had inertial dampers on its rear wheel hubs to damp only wheel bounce.Road condition Cars with relatively soft suspension and with low unsprung weight are least affected by uneven surfaces, while on flat smooth surfaces the stiffer the better. Unexpected water, ice, oil, etc. are hazards.

Factors that affect a car's handling Weight distribution Centre of mass height The centre of mass height, also known as the centre of gravity height, or CGZ, relative to the track, determines load transfer (related to, but not exactly weight transfer) from side to side and causes body lean. When tires of a vehicle provide a centripetal force to pull it around a turn, the momentum of the vehicle actuates load transfer in a direction going from the vehicle's current position to a point on a path tangent to the vehicle's path. This load transfer presents itself in the form of body lean. In extreme circumstances, the vehicle may roll over. Height of the centre of mass relative to the wheelbase determines load transfer between front and rear. The car's momentum acts at its centre of mass to tilt the car forward or backward, respectively during braking and acceleration. Since it is only the downward force that changes and not the location of the centre of mass, the effect on over/under steer is opposite to that of an actual change in the centre of mass. When a car is braking, the downward load on the front tires increases and that on the rear decreases, with corresponding change in their ability to take sideways load. A lower centre of mass is a principal performance advantage of sports cars, compared to sedans and (especially) SUVs. Some cars have body panels made of lightweight materials partly for this reason. Body lean can also be controlled by the springs, anti-roll bars or the roll center heights.Yaw and pitch angular inertia (polar moment) Unless the vehicle is very short, compared to its height or width, these are about equal. Angular inertia determines the rotational inertia of an object for a given rate of rotation. The yaw angular inertia tends to keep the direction the car is pointing changing at a constant rate. This makes it slower to swerve or go into a tight curve, and it also makes it slower to turn straight again. The pitch angular inertia detracts from the ability of the suspension to keep front and back tire loadings constant on uneven surfaces and therefore contributes to bump steer. Angular inertia is an integral over the square of the distance from the center of gravity, so it favors small cars even though the lever arms (wheelbase and track) also increase with scale. (Since cars have reasonable symmetrical shapes, the off-diagonal terms of the angular inertia tensor can usually be ignored.) Mass near the ends of a car can be avoided, without re-designing it to be shorter, by the use of light materials for bumpers and fenders or by deleting them entirely. If most of the weight is in the middle of the car then the vehicle will be easier to spin, and therefore will react quicker to a turn.

Track and wheelbase The axle track provides the resistance to lateral weight transfer and body lean. The wheelbase provides resistance to longitudinal weight transfer and to pitch angular inertia, and provides the torque lever arm to rotate the car when swerving. The wheelbase, however, is less important than angular inertia (polar moment) to the vehicle's ability to swerve quickly. The wheelbase contributes to the vehicle's turning radius, which is also a handling characteristic.

Steering Depending on the driver, steering force and transmission of road forces back to the steering wheel and the steering ratio of turns of the steering wheel to turns of the road wheels affect control and awareness. Play—free rotation of the steering wheel before the wheels rotate—is a common problem, especially in older model and worn cars. Another is friction. Rack and pinion steering is generally considered the best type of mechanism for control effectiveness. The linkage also contributes play and friction. Caster—offset of the steering axis from the contact patch—provides some of the self-centering tendency. Precision of the steering is particularly important on ice or hard packed snow where the slip angle at the limit of adhesion is smaller than on dry roads. The steering effort depends on the downward force on the steering tires and on the radius of the contact patch. So for constant tire pressure, it goes like the 1.5 power of the vehicle's weight. The driver's ability to exert torque on the wheel scales similarly with his size. The wheels must be rotated farther on a longer car to turn with a given radius. Power steering reduces the required force at the expense of feel. It is useful, mostly in parking, when the weight of a front-heavy vehicle exceeds about ten or fifteen times the driver's weight, for physically impaired drivers and when there is much friction in the steering mechanism. Four-wheel steering has begun to be used on road cars (Some WW II reconnaissance vehicles had it). It relieves the effect of angular inertia by starting the whole car moving before it rotates toward the desired direction. It can also be used, in the other direction, to reduce the turning radius. Some cars will do one or the other, depending on the speed. Steering geometry changes due to bumps in the road may cause the front wheels to steer in different directions together or independent of each other. The steering linkage should be designed to minimize this effect.Static alignment of the wheels Of course things should be the same, left and right, for road cars. Camber affects steering because a tire generates a force towards the side that the top is leaning towards. This is called camber thrust. Additional front negative camber is used to improve the cornering ability of cars with insufficient camber gain.Rigidity of the frame The frame may flex with load, especially twisting on bumps. Rigidity is considered to help handling. At least it simplifies the suspension engineers work. Some cars, such as the Mercedes-Benz 300SL have had high doors to allow a stiffer frame.Driver handling the car Handling is a property of the car, but different characteristics will work well with different drivers.Familiarity The more experience a person has with a car or type of car the more likely they will be to take full advantage of its handling characteristics under adverse conditions.Common handling problems When any wheel leaves contact with the road there is a change in handling, so the suspension should keep all four (or three) wheels on the road in spite of hard cornering, swerving and bumps in the road. It is very important for handling, as well as other reasons, not to run out of suspension travel and "bottom" or "top". It is usually most desirable to have the car adjusted for a small amount of understeer, so that it responds predictably to a turn of the steering wheel and the rear wheels have a smaller slip angle than the front wheels. However this may not be achievable for all loading, road and weather conditions, speed ranges, or while turning under acceleration or braking. Ideally, a car should carry passengers and baggage near its center of gravity and have similar tire loading, camber angle and roll stiffness in front and back to minimise the variation in handling characteristics. A driver can learn to deal with excessive oversteer or understeer, but not if it varies greatly in a short period of time. The most important common handling failings are;Compromises Ride quality and handling have always been a compromise - technology has over time allowed automakers to combine more of both features in the same vehicle. High levels of comfort are difficult to reconcile with a low center of gravity, body roll resistance, low angular inertia, support for the driver, steering feel and other characteristics that make a car handle well. For ordinary production cars, manufactures err towards deliberate understeer as this is safer for inexperienced or inattentive drivers than is oversteer. Other compromises involve comfort and utility, such as preference for a softer smoother ride or more seating capacity. Inboard brakes improve both handling and comfort but take up space and are harder to cool. Large engines tend to make cars front or rear heavy. Fuel economy, staying cool at high speeds, ride comfort and long wear all tend to conflict with road holding, while wet, dry, deep water and snow road holding are not exactly compatible. A-arm or wishbone front suspension tends to give better handling, because it provides the engineers more freedom to choose the geometry, and more road holding, because the camber is better suited to radial tires, than MacPherson strut, but it takes more space. The older Live axle rear suspension technology, familiar from the Ford Model T, is still widely used in most sport utility vehicles and trucks, often for the purposes of durability (and cost). The live axle suspension is still used in some sports cars, like the Ford Mustang (model years before 2015), and is better for drag racing, but generally has problems with grip on bumpy corners, fast corners and stability at high speeds on bumpy straights.

Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition. In the automotive industry, handling and braking are the major components of a vehicle's "active" safety, as well as its ability to perform in auto racing. The maximum lateral acceleration is sometimes discussed separately as "road holding". (This discussion is directed at road vehicles with at least three wheels, but some of it may apply to other ground vehicles). Automobiles driven on public roads whose engineering requirements emphasize handling over comfort and passenger space are named sports cars.

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Anti-communism is political and ideological opposition to communist beliefs, groups, and individuals. Organized anti-communism developed after the 1917 October Revolution in the Russian Empire, and it reached global dimensions during the Cold War, when the United States and the Soviet Union engaged in an intense rivalry. Anti-communism has been an element of many movements and different political positions across the political spectrum, including anarchism, centrism, conservatism, fascism, liberalism, nationalism, social democracy, socialism, leftism, and libertarianism, as well as broad movements resisting communist governance. Anti-communism has also been expressed in philosophy, by several religious groups, and in literature. Some well-known proponents of anti-communism are former communists. The first organization which was specifically dedicated to opposing communism was the Russian White movement, which fought in the Russian Civil War starting in 1918 against the recently established Bolshevik government. The White movement was militarily supported by several allied foreign governments which represented the first instance of anti-communism as a government policy. Nevertheless, the Red Army defeated the White movement and the Soviet Union was created in 1922. During the existence of the Soviet Union, anti-communism became an important feature of many different political movements and governments across the world. In the United States, anti-communism came to prominence during the First Red Scare of 1919–1920. During the 1920s and 1930s, opposition to communism in Europe was promoted by conservatives, monarchists, fascists, liberals, and social democrats. Fascist governments rose to prominence as major opponents of communism in the 1930s. Liberal and social democrats in Germany formed the Iron Front to oppose communists, Nazi fascists, and revanchist conservative monarchists alike. In 1936, the Anti-Comintern Pact, initially between Nazi Germany and Imperial Japan, was formed as an anti-communist alliance. In Asia, Imperial Japan and the Kuomintang (Chinese Nationalist Party) were the leading anti-communist forces in this period. By 1945, the communist Soviet Union was among major Allied nations fighting against the Axis powers in World War II. Shortly after the end of the war, rivalry between the Marxist–Leninist Soviet Union and liberal capitalist United States resulted in the Cold War. During this period, the United States government played a leading role in supporting global anti-communism as part of its containment policy. Military conflicts between communists and anti-communists occurred in various parts of the world, including during the Chinese Civil War, the Korean War, the Malayan Emergency, the Vietnam War, the Soviet–Afghan War, and Operation Condor. NATO was founded as an anti-communist military alliance in 1949, and continued throughout the Cold War. After the Revolutions of 1989 and the dissolution of the Soviet Union in 1991, most of the world's communist governments were overthrown, and the Cold War ended. Nevertheless, anti-communism remains an important intellectual element of many contemporary political movements. Organized anti-communist movements remain in opposition to the People's Republic of China and other communist nations.White movement The White movement was a loose confederation of anti-communist forces that fought against the communist Bolsheviks, also known as the Reds, in the Russian Civil War. After the civil war, the movement continued operating to a lesser extent as militarized associations of insurrectionists both outside and within Russian borders in Siberia until roughly World War II. During the Russian Civil War, the White movement functioned as a big-tent political movement representing an array of political opinions in Russia united in their opposition to the communist Bolsheviks. They ranged from the republican-minded liberals and Kerenskyite social-democrats on the left through monarchists and supporters of a united multinational Russia to the ultra-nationalist Black Hundreds on the right. Following the military defeat of the Whites, remnants and continuations of the movement remained in several organizations, some of which only had narrow support, enduring within the wider White émigré overseas community until after the fall of the European communist states in the Revolutions of 1989 and the subsequent dissolution of the Soviet Union in 1990–1991. This community-in-exile of anti-communists often divided into liberal-leaning and conservative-leaning segments, with some still hoping for the restoration of the Romanov dynasty. Two claimants to the empty throne emerged during the Civil War, Grand Duke Kirill Vladimirovich of Russia and Grand Duke Nicholas Nikolaevich of Russia.Asia Republic of China & Taiwan Before the founding of the People's Republic of China, the Kuomintang, also known as the Chinese Nationalist Party, led by Chiang Kai-shek, was ruling China and strongly opposed the Chinese Communist Party. On 12 April 1927, Chiang Kai-shek purged the communists in what was known as the Shanghai massacre which led to the Chinese Civil War. Initially, the Kuomintang had success in doing so until a full-scale invasion of China by Japan forced both the Nationalists and the Communists into an alliance. On 28 February 1947, the Kuomintang had cracked down on an anti-government communist uprising in Taiwan, a former Qing province-turned-Japanese colony ruled from 1895 to 1945, known as the February 28 incident and the government began the White Terror in Taiwan in order to purge the communist spies in order to prevent Chinese communist subversion. After the war, the two parties were thrown back into a civil war. The Kuomintang were defeated in the mainland and escaped in exile to Taiwan while the rest of mainland China became Communist in 1949. Shortly afterwards, the Republic of China government remained anti-communist and attempted to recover the mainland from the Communist forces. During the Cold War, the Republic of China was known as Free China while the People's Republic of China on the mainland China was known as Red China or Communist China in the West, to mark the ideological difference between the Free World and Communist Socialist World. The Republic of China government also actively supported anti-communist efforts in Southeast Asia and around the world. This effort did not cease until the death of Chiang Kai-shek in 1975.Even though contacts between Kuomintang and Chinese Communist Party had existed since the 1990s to re-establish Cross-Strait relations, the Kuomintang continues to be opposed to communism, as anti-communism is written under Article 2 of Kuomintang's party charterPeople's Republic of China The Chinese democracy movement is a loosely organized anti-communist movement in the People's Republic of China. The movement began during the Beijing Spring in 1978 and it also played an important role in the Tiananmen Square protests of 1989. The 1959 Tibetan Rebellion had some anti-communist leanings. In the 1990s, the movement underwent a decline both within China and overseas. It is currently fragmented and most analysts do not consider it a serious threat to Communist rule. Charter 08 is a manifesto which was signed by over 303 Chinese intellectuals and human rights activists who seek to promote political reform and democratization in the People's Republic of China. It calls for greater freedom of expression and free elections. It was published on 10 December 2008, the 60th anniversary of the adoption of the Universal Declaration of Human Rights. Its name is a reference to Charter 77 which was issued by dissidents in Czechoslovakia. Since its release, the charter has been signed by more than 8,100 people both inside and outside of China.India India is involved in law and order operations against a long-standing Naxalite–Maoist insurgency. Along with this, there are many state-sponsored anti-Maoist militias. Some political parties like All India Trinamool Congress are also engaged in active anti-communist movement to topple elected communist governments. In 2011 West Bengal Legislative Assembly elections, Mamata Banarji led her party AITC to a landslide win over the ruling Left Front that had become the world's longest ruling democratically elected communist government.

United States 1920s and 1930s The first major manifestation of anti-communism in the United States occurred in 1919 and 1920 during the First Red Scare, led by Attorney General Alexander Mitchell Palmer. During the Red Scare, the Lusk Committee investigated those suspected of sedition and many laws were passed in the United States that sanctioned the firings of Communists. The Hatch Act of 1939, which was sponsored by Carl Hatch of New Mexico, attempted to drive communism out of public work places. The Hatch Act outlawed the hiring of federal workers who advocated the "overthrow of our Constitutional form of government". This phrase was specifically directed at the Communist Party USA. Later in the spring of 1941, another anti-communist law was passed, Public Law 135, which sanctioned the investigation of any federal worker suspected of being Communist and the firing of any Communist worker.

Post-Cold War era developments Anti-communism became significantly muted after the 1980s–1990s Chinese economic reform and the fall of the Soviet Union and Eastern bloc Communist governments in Europe between 1989 and 1991, the result of which being that fear of a worldwide Communist takeover was no longer a serious concern. However, remnants of anti-communism remain in foreign policy with regard to Cuba and North Korea. In the case of Cuba, it was not until the Obama administration that the United States began to weaken (though not lift) its economic sanctions against the country. Tensions with North Korea have heightened as the result of reports that it is stockpiling nuclear weapons and the assertion that it is willing to sell its nuclear weapons and ballistic missile technology to any group willing to pay a high enough price. Ideological restrictions on naturalization in United States law remain in effect, affecting prospective immigrants who were at one time members of a Communist party and the Communist Control Act which outlaws the Communist Party still remains in effect, although it was never enforced by the Federal Government. Some states also still have laws banning Communists from working in the state government. Since the September 11 attacks on the United States and the subsequent implementation of the Patriot Act which was overwhelmingly passed by Congress and signed into law and strongly supported by President Bush, some Communist groups in the United States have been subjected to renewed scrutiny by the government. On 24 September 2010, over 70 FBI agents simultaneously raided homes and served subpoenas to prominent antiwar and international solidarity activists who were thought to be members of the Freedom Road Socialist Organization (FRSO) in Minneapolis, Chicago and Grand Rapids and they also visited and attempted to question activists in Milwaukee, Durham and San Jose. The search warrants and subpoenas indicated that the FBI was looking for evidence that was related to their "material support of terrorism". In the process of raiding an activist's home, FBI agents accidentally left behind a file of secret FBI documents which showed that the raids were aimed at people who were actual or suspected members of the FRSO. The documents revealed a series of questions that agents would ask activists regarding their involvement in the FRSO and their international solidarity work that was related to their dealings with the Revolutionary Armed Forces of Colombia and the Popular Front for the Liberation of Palestine. Later, members of the newly formed Committee to Stop FBI Repression held a press conference in Minnesota in which they revealed that the FBI had placed an informant inside the FRSO in order to gather information prior to the raids.On October 2, 2020, the United States Citizenship and Immigration Services issued policy guidance in the USCIS Policy Manual to address inadmissibility based on membership in or affiliation with a communist party or any other totalitarian party. It said that unless otherwise exempt, any intending immigrant who was a member or affiliate of a communist or totalitarian party, or subdivision or affiliate, domestic or foreign, was inadmissible to the United States. It also indicated that a member of a communist party or any other totalitarian party was inconsistent and incompatible with the naturalization Oath of Allegiance to the United States.

South America During the 1970s, the right-wing military juntas of South America implemented Operation Condor, a campaign of political repression involving tens of thousands of political assassinations, illegal detentions and tortures of communist sympathizers. The campaign was aimed at eradicating alleged communist and socialist influences in their respective countries and control opposition against the government, which resulted in a large number of deaths. Participatory governments include Argentina, Bolivia, Paraguay, Brazil, Chile and Uruguay, with limited support from the United States.

Post–World War II In most of the states of the North Atlantic Treaty Organization, such as the United States, the United Kingdom and West Germany, as well as the Soviet Bloc, and especially in the neutral countries, such as Switzerland and in Sweden during the 1950s and 1960s, many civil defense practices took place to prepare for the aftermath of a nuclear war, which seemed quite likely at that time.In the United Kingdom, the Civil Defence Service was disbanded in 1945, followed by the ARP in 1946. With the onset of the growing tensions between East and West, the service was revived in 1949 as the Civil Defence Corps. As a civilian volunteer organization, it was tasked to take control in the aftermath of a major national emergency, principally envisaged as being a Cold War nuclear attack. Although under the authority of the Home Office, with a centralized administrative establishment, the corps was administered locally by Corps Authorities. In general every county was a Corps Authority, as were most county boroughs in England and Wales and large burghs in Scotland. Each division was divided into several sections, including the Headquarters, Intelligence and Operations, Scientific and Reconnaissance, Warden & Rescue, Ambulance and First Aid and Welfare. In 1954 Coventry City Council caused international controversy when it announced plans to disband its Civil Defence committee because the councillors had decided that hydrogen bombs meant that there could be no recovery from a nuclear attack. The British government opposed such a move and held a provocative Civil Defence exercise on the streets of Coventry which Labour council members protested against. The government also decided to implement its own committee at the city's cost until the council reinstituted its committee. In the United States, the sheer power of nuclear weapons and the perceived likelihood of such an attack precipitated a greater response than had yet been required of civil defense. Civil defense, previously considered an important and commonsense step, became divisive and controversial in the charged atmosphere of the Cold War. In 1950, the National Security Resources Board created a 162-page document outlining a model civil defense structure for the U.S. Called the "Blue Book" by civil defense professionals in reference to its solid blue cover, it was the template for legislation and organization for the next 40 years.The US President Kennedy (1961–63) launched an ambitious effort to install fallout shelters throughout the United States. These shelters would not protect against the blast and heat effects of nuclear weapons, but would provide some protection against the radiation effects that would last for weeks and even affect areas distant from a nuclear explosion. In order for most of these preparations to be effective, there had to be some degree of warning. In 1951, CONELRAD (Control of Electromagnetic Radiation) was established. Under the system, a few primary stations would be alerted of an emergency and would broadcast an alert. All broadcast stations throughout the country would be constantly listening to an upstream station and repeat the message, thus passing it from station to station. In a once classified US war game analysis, looking at varying levels of war escalation, warning and pre-emptive attacks in the late 1950s early 1960s, it was estimated that approximately 27 million US citizens would have been saved with civil defense education. At the time, however, the cost of a full-scale civil defense program was regarded as less effective in cost-benefit analysis than a ballistic missile defense (Nike Zeus) system, and as the Soviet adversary was increasing their nuclear stockpile, the efficacy of both would follow a diminishing returns trend.Contrary to the largely noncommittal approach taken in NATO, with its stops and starts in civil defense depending on the whims of each newly elected government, the military strategy in the comparatively more ideologically consistent USSR held that, amongst other things, a winnable nuclear war was possible. To this effect the Soviets planned to minimize, as far as possible, the effects of nuclear weapon strikes on its territory, and therefore spent considerably more thought on civil defense preparations than in U.S., with defense plans that have been assessed to be far more effective than those in the U.S.Soviet Civil Defense Troops played the main role in the massive disaster relief operation following the 1986 Chernobyl nuclear accident. Defense Troop reservists were officially mobilized (as in a case of war) from throughout the USSR to join the Chernobyl task force and formed on the basis of the Kyiv Civil Defense Brigade. The task force performed some high-risk tasks including, with the failure of their robotic machinery, the manual removal of highly-radioactive debris. Many of their personnel were later decorated with medals for their work at containing the release of radiation into the environment, with a number of the 56 deaths from the accident being Civil defense troops.

Civil defense (British English: civil defence) or civil protection is an effort to protect the citizens of a state (generally non-combatants) from man-made and natural disasters. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation and recovery. Programs of this sort were initially discussed at least as early as the 1920s and were implemented in some countries during the 1930s as the threat of war and aerial bombardment grew. Civil-defense structures became widespread after authorities recognised the threats posed by nuclear weapons. Since the end of the Cold War, the focus of civil defense has largely shifted from responding to military attack to dealing with emergencies and disasters in general. The new concept is characterised by a number of terms, each of which has its own specific shade of meaning, such as crisis management, emergency management, emergency preparedness, contingency planning, civil contingency, civil aid and civil protection. Some countries treat civil defense as a key part of defense in general. For example, the Swedish-language word totalförsvar ("total defense") refers to the commitment of a wide range of national resources to defense, including the protection of all aspects of civilian life. Some countries have organized civil defense along paramilitary lines, or have incorporated it within armed forces, such as the Soviet Civil Defense Forces (Войска гражданской обороны).In Western countries, strong civil defense policies were never properly implemented, because it was fundamentally at odds with the doctrine of "mutual assured destruction" (MAD) by making provisions for survivors. It was also considered that a full-fledged total defense would have not been worth the very large expense. For whatever reason, the public saw efforts at civil defense as fundamentally ineffective against the powerful destructive forces of nuclear weapons, and therefore a waste of time and money, although detailed scientific research programs did underlie the much-mocked government civil defense pamphlets of the 1950s and 1960s.The Civil Defence Corps was stood down in Great Britain in 1968 due to the financial crisis of the mid-1960s. Its neighbors, however, remained committed to Civil Defence, namely the Isle of Man Civil Defence Corps and Civil Defence Ireland (Republic of Ireland). In the United States, the various civil defense agencies were replaced with the Federal Emergency Management Agency (FEMA) in 1979. In 2002 this became part of the Department of Homeland Security. The focus was shifted from nuclear war to an "all-hazards" approach of Comprehensive Emergency Management. Natural disasters and the emergence of new threats such as terrorism have caused attention to be focused away from traditional civil defense and into new forms of civil protection such as emergency management and homeland security.

Civil defense (British English: civil defence) or civil protection is an effort to protect the citizens of a state (generally non-combatants) from man-made and natural disasters. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation and recovery. Programs of this sort were initially discussed at least as early as the 1920s and were implemented in some countries during the 1930s as the threat of war and aerial bombardment grew. Civil-defense structures became widespread after authorities recognised the threats posed by nuclear weapons. Since the end of the Cold War, the focus of civil defense has largely shifted from responding to military attack to dealing with emergencies and disasters in general. The new concept is characterised by a number of terms, each of which has its own specific shade of meaning, such as crisis management, emergency management, emergency preparedness, contingency planning, civil contingency, civil aid and civil protection. Some countries treat civil defense as a key part of defense in general. For example, the Swedish-language word totalförsvar ("total defense") refers to the commitment of a wide range of national resources to defense, including the protection of all aspects of civilian life. Some countries have organized civil defense along paramilitary lines, or have incorporated it within armed forces, such as the Soviet Civil Defense Forces (Войска гражданской обороны).

Civil defense (British English: civil defence) or civil protection is an effort to protect the citizens of a state (generally non-combatants) from man-made and natural disasters. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation and recovery. Programs of this sort were initially discussed at least as early as the 1920s and were implemented in some countries during the 1930s as the threat of war and aerial bombardment grew. Civil-defense structures became widespread after authorities recognised the threats posed by nuclear weapons. Since the end of the Cold War, the focus of civil defense has largely shifted from responding to military attack to dealing with emergencies and disasters in general. The new concept is characterised by a number of terms, each of which has its own specific shade of meaning, such as crisis management, emergency management, emergency preparedness, contingency planning, civil contingency, civil aid and civil protection. Some countries treat civil defense as a key part of defense in general. For example, the Swedish-language word totalförsvar ("total defense") refers to the commitment of a wide range of national resources to defense, including the protection of all aspects of civilian life. Some countries have organized civil defense along paramilitary lines, or have incorporated it within armed forces, such as the Soviet Civil Defense Forces (Войска гражданской обороны).The US President Kennedy (1961–63) launched an ambitious effort to install fallout shelters throughout the United States. These shelters would not protect against the blast and heat effects of nuclear weapons, but would provide some protection against the radiation effects that would last for weeks and even affect areas distant from a nuclear explosion. In order for most of these preparations to be effective, there had to be some degree of warning. In 1951, CONELRAD (Control of Electromagnetic Radiation) was established. Under the system, a few primary stations would be alerted of an emergency and would broadcast an alert. All broadcast stations throughout the country would be constantly listening to an upstream station and repeat the message, thus passing it from station to station. In a once classified US war game analysis, looking at varying levels of war escalation, warning and pre-emptive attacks in the late 1950s early 1960s, it was estimated that approximately 27 million US citizens would have been saved with civil defense education. At the time, however, the cost of a full-scale civil defense program was regarded as less effective in cost-benefit analysis than a ballistic missile defense (Nike Zeus) system, and as the Soviet adversary was increasing their nuclear stockpile, the efficacy of both would follow a diminishing returns trend.Contrary to the largely noncommittal approach taken in NATO, with its stops and starts in civil defense depending on the whims of each newly elected government, the military strategy in the comparatively more ideologically consistent USSR held that, amongst other things, a winnable nuclear war was possible. To this effect the Soviets planned to minimize, as far as possible, the effects of nuclear weapon strikes on its territory, and therefore spent considerably more thought on civil defense preparations than in U.S., with defense plans that have been assessed to be far more effective than those in the U.S.Soviet Civil Defense Troops played the main role in the massive disaster relief operation following the 1986 Chernobyl nuclear accident. Defense Troop reservists were officially mobilized (as in a case of war) from throughout the USSR to join the Chernobyl task force and formed on the basis of the Kyiv Civil Defense Brigade. The task force performed some high-risk tasks including, with the failure of their robotic machinery, the manual removal of highly-radioactive debris. Many of their personnel were later decorated with medals for their work at containing the release of radiation into the environment, with a number of the 56 deaths from the accident being Civil defense troops.NuclearShelter intended to protect against nuclear blast effects would include thick concrete and other sturdy elements which are resistant to conventional explosives. The biggest threats from a nuclear attack are effects from the blast, fires and radiation. One of the most prepared countries for a nuclear attack is Switzerland. Almost every building in Switzerland has an abri (shelter) against the initial nuclear bomb and explosion followed by the fall-out. Because of this, many people use it as a safe to protect valuables, photos, financial information and so on. Switzerland also has air-raid and nuclear-raid sirens in every village.

Civil defense (British English: civil defence) or civil protection is an effort to protect the citizens of a state (generally non-combatants) from man-made and natural disasters. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation and recovery. Programs of this sort were initially discussed at least as early as the 1920s and were implemented in some countries during the 1930s as the threat of war and aerial bombardment grew. Civil-defense structures became widespread after authorities recognised the threats posed by nuclear weapons. Since the end of the Cold War, the focus of civil defense has largely shifted from responding to military attack to dealing with emergencies and disasters in general. The new concept is characterised by a number of terms, each of which has its own specific shade of meaning, such as crisis management, emergency management, emergency preparedness, contingency planning, civil contingency, civil aid and civil protection. Some countries treat civil defense as a key part of defense in general. For example, the Swedish-language word totalförsvar ("total defense") refers to the commitment of a wide range of national resources to defense, including the protection of all aspects of civilian life. Some countries have organized civil defense along paramilitary lines, or have incorporated it within armed forces, such as the Soviet Civil Defense Forces (Войска гражданской обороны).

Distraction is the process of diverting the attention of an individual or group from a desired area of focus and thereby blocking or diminishing the reception of desired information. Distraction is caused by: the lack of ability to pay attention; lack of interest in the object of attention; or the great intensity, novelty or attractiveness of something other than the object of attention. Distractions come from both external sources, and internal sources. External distractions include factors such as visual triggers, social interactions, music, text messages, and phone calls. There are also internal distractions such as hunger, fatigue, illness, worrying, and daydreaming. Both external and internal distractions contribute to the interference of focus.

Distraction is the process of diverting the attention of an individual or group from a desired area of focus and thereby blocking or diminishing the reception of desired information. Distraction is caused by: the lack of ability to pay attention; lack of interest in the object of attention; or the great intensity, novelty or attractiveness of something other than the object of attention. Distractions come from both external sources, and internal sources. External distractions include factors such as visual triggers, social interactions, music, text messages, and phone calls. There are also internal distractions such as hunger, fatigue, illness, worrying, and daydreaming. Both external and internal distractions contribute to the interference of focus.

Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.Malaria is caused by single-celled microorganisms of the Plasmodium group. It is spread exclusively through bites of infected Anopheles mosquitoes. The mosquito bite introduces the parasites from the mosquito's saliva into a person's blood. The parasites travel to the liver where they mature and reproduce. Five species of Plasmodium can infect and be spread by humans. Most deaths are caused by P. falciparum, whereas P. vivax, P. ovale, and P. malariae generally cause a milder form of malaria. The species P. knowlesi rarely causes disease in humans. Malaria is typically diagnosed by the microscopic examination of blood using blood films, or with antigen-based rapid diagnostic tests. Methods that use the polymerase chain reaction to detect the parasite's DNA have been developed, but they are not widely used in areas where malaria is common, due to their cost and complexity.The risk of disease can be reduced by preventing mosquito bites through the use of mosquito nets and insect repellents or with mosquito-control measures such as spraying insecticides and draining standing water. Several medications are available to prevent malaria for travellers in areas where the disease is common. Occasional doses of the combination medication sulfadoxine/pyrimethamine are recommended in infants and after the first trimester of pregnancy in areas with high rates of malaria. As of 2020, there is one vaccine which has been shown to reduce the risk of malaria by about 40% in children in Africa. A pre-print study of another vaccine has shown 77% vaccine efficacy. Efforts to develop more effective vaccines are ongoing. The recommended treatment for malaria is a combination of antimalarial medications that includes artemisinin. The second medication may be either mefloquine, lumefantrine, or sulfadoxine/pyrimethamine. Quinine, along with doxycycline, may be used if artemisinin is not available. It is recommended that in areas where the disease is common, malaria is confirmed if possible before treatment is started due to concerns of increasing drug resistance. Resistance among the parasites has developed to several antimalarial medications; for example, chloroquine-resistant P. falciparum has spread to most malarial areas, and resistance to artemisinin has become a problem in some parts of Southeast Asia.The disease is widespread in the tropical and subtropical regions that exist in a broad band around the equator. This includes much of sub-Saharan Africa, Asia, and Latin America. In 2021 there were 247 million cases of malaria worldwide resulting in an estimated 619,000 deaths. Approximately 95% of the cases and deaths occurred in sub-Saharan Africa. Rates of disease decreased from 2010 to 2014 but increased from 2015 to 2021. Malaria is commonly associated with poverty and has a significant negative effect on economic development. In Africa, it is estimated to result in losses of US$12 billion a year due to increased healthcare costs, lost ability to work, and adverse effects on tourism.Society and culture Economic impact Malaria is not just a disease commonly associated with poverty: some evidence suggests that it is also a cause of poverty and a major hindrance to economic development. Although tropical regions are most affected, malaria's furthest influence reaches into some temperate zones that have extreme seasonal changes. The disease has been associated with major negative economic effects on regions where it is widespread. During the late 19th and early 20th centuries, it was a major factor in the slow economic development of the American southern states.A comparison of average per capita GDP in 1995, adjusted for parity of purchasing power, between countries with malaria and countries without malaria gives a fivefold difference (US$1,526 versus US$8,268). In the period 1965 to 1990, countries where malaria was common had an average per capita GDP that increased only 0.4% per year, compared to 2.4% per year in other countries.Poverty can increase the risk of malaria since those in poverty do not have the financial capacities to prevent or treat the disease. In its entirety, the economic impact of malaria has been estimated to cost Africa US$12 billion every year. The economic impact includes costs of health care, working days lost due to sickness, days lost in education, decreased productivity due to brain damage from cerebral malaria, and loss of investment and tourism. The disease has a heavy burden in some countries, where it may be responsible for 30–50% of hospital admissions, up to 50% of outpatient visits, and up to 40% of public health spending.

Sweden Swedish statistics and politics have used three different definitions over the years: The most dramatic change took place according to "norm 2" between 1960 and 1975 because of the Million Programme. Of the households that are regarded as overcrowded according to "norm 3", two thirds are single persons living in 1-room apartments without a separate living room.

Manners Sociological perspectives In a society, manners are described as either good manners or as bad manners to indicate to a person whether or not his or her behaviour is acceptable to the cultural group. As such, manners enable ultrasociality and are integral to the functioning of the social norms and conventions that are informally enforced through personal self-regulation in public life and in private life. The perspectives of sociology indicate that manners are a means for people to display their social status, and a means of demarcating, observing, and maintaining the boundaries of social identity and of social class.In The Civilizing Process (1939), the sociologist Norbert Elias said that manners arose as a product of group living, and persist as a way of maintaining social order. That manners proliferated during the Renaissance in response to the development of the ‘absolute state’—the progression from small-group living to large-group living characterised by the centralized power of the State. That the rituals and manners associated with the royal court of England during that period were closely bound to a person's social status. That manners demonstrate a person's position within a social network, and that a person's manners are a means of negotiation from that social position.From the perspective of public health, in The Healthy Citizen (1996), Alana R. Petersen and Deborah Lupton said that manners assisted the diminishment of the social boundaries that existed between the public sphere and the private sphere of a person's life, and so gave rise to “a highly reflective self, a self who monitors his or her behavior with due regard for others with whom he or she interacts, socially”; and that “the public behavior of individuals came to signify their social standing; a means of presenting the self and of evaluating others, and thus the control of the outward self was vital.”Moreover, the sociologist Pierre Bourdieu applied the concept of habitus to define the societal functions of manners. The habitus is the set of mental attitudes, personal habits, and skills that a person possesses, his and her dispositions of character that are neither self-determined, nor pre-determined by the external environment, but which are produced and reproduced by social interactions; and are “inculcated through experience and explicit teaching”—yet tend to function at the subconscious level. Therefore, manners are likely to be a central part of the dispositions that guide a person’s ability to decide upon socially-compliant behaviours.Business In commerce, the purpose of etiquette is to facilitate the social relations necessary for realising the business transactions of buying and selling goods and services; in particular, the social interactions among the workers, and between labour and management. Business etiquette varies by culture, such as the Chinese and Australian approaches to conflict resolution. The Chinese business philosophy is based upon guanxi (personal connections), whereby person-to-person negotiation resolves difficult matters, whereas Australian business philosophy relies upon attorneys-at-law to resolve business conflicts through legal mediation; thus, adjusting to the etiquette and professional ethics of another culture is an element of culture shock for businesspeople.In 2011, etiquette trainers formed the Institute of Image Training and Testing International (IITTI) a non-profit organisation to train personnel departments in measuring and developing and teaching social skills to employees, by way of education in the rules of personal and business etiquette, in order to produce business workers who possess standardised manners for successfully conducting business with people from other cultures. In the retail branch of commerce, the saying: "The customer is always right." summarises the profit-orientation of good manners, between the buyer and the seller of goods and services:

Etiquette () is the set of norms of personal behaviour in polite society, usually occurring in the form of an ethical code of the expected and accepted social behaviours that accord with the conventions and norms observed and practised by a society, a social class, or a social group. In modern English usage, the French word étiquette (label and tag) dates from the year 1750.

Politeness In the 18th century, during the Age of Enlightenment, the adoption of etiquette was a self-conscious process for acquiring the conventions of politeness and the normative behaviours (charm, manners, demeanour) which symbolically identified the person as a genteel member of the upper class. To identify with the social élite, the upwardly mobile middle class and the bourgeoisie adopted the behaviours and the artistic preferences of the upper class. To that end, socially ambitious people of the middle classes occupied themselves with learning, knowing, and practising the rules of social etiquette, such as the arts of elegant dress and gracious conversation, when to show emotion, and courtesy with and towards women.In the early 18th century, Anthony Ashley-Cooper, 3rd Earl of Shaftesbury, wrote influential essays that defined politeness as the art of being pleasing in company; and discussed the function and nature of politeness in the social discourse of a commercial society:Manners Sociological perspectives In a society, manners are described as either good manners or as bad manners to indicate to a person whether or not his or her behaviour is acceptable to the cultural group. As such, manners enable ultrasociality and are integral to the functioning of the social norms and conventions that are informally enforced through personal self-regulation in public life and in private life. The perspectives of sociology indicate that manners are a means for people to display their social status, and a means of demarcating, observing, and maintaining the boundaries of social identity and of social class.In The Civilizing Process (1939), the sociologist Norbert Elias said that manners arose as a product of group living, and persist as a way of maintaining social order. That manners proliferated during the Renaissance in response to the development of the ‘absolute state’—the progression from small-group living to large-group living characterised by the centralized power of the State. That the rituals and manners associated with the royal court of England during that period were closely bound to a person's social status. That manners demonstrate a person's position within a social network, and that a person's manners are a means of negotiation from that social position.From the perspective of public health, in The Healthy Citizen (1996), Alana R. Petersen and Deborah Lupton said that manners assisted the diminishment of the social boundaries that existed between the public sphere and the private sphere of a person's life, and so gave rise to “a highly reflective self, a self who monitors his or her behavior with due regard for others with whom he or she interacts, socially”; and that “the public behavior of individuals came to signify their social standing; a means of presenting the self and of evaluating others, and thus the control of the outward self was vital.”Moreover, the sociologist Pierre Bourdieu applied the concept of habitus to define the societal functions of manners. The habitus is the set of mental attitudes, personal habits, and skills that a person possesses, his and her dispositions of character that are neither self-determined, nor pre-determined by the external environment, but which are produced and reproduced by social interactions; and are “inculcated through experience and explicit teaching”—yet tend to function at the subconscious level. Therefore, manners are likely to be a central part of the dispositions that guide a person’s ability to decide upon socially-compliant behaviours.Evolutionary perspectives In studying the expression of emotion by humans and animals, the naturalist Charles Darwin noted the universality of facial expressions of disgust and shame among infants and blind people, and concluded that the emotional responses of shame and disgust are innate behaviours. The public health specialist Valerie Curtis said that the development of facial responses was concomitant with the development of manners, which are behaviours with an evolutionary role in preventing the transmission of diseases, thus, people who practise personal hygiene and politeness will most benefit from membership in their social group, and so stand the best chance of biological survival, by way of opportunities for reproduction.From the study of the evolutionary bases of prejudice, the social psychologists Catherine Cottrell and Steven Neuberg said that human behavioural responses to ‘otherness’ might enable the preservation of manners and social norms. That the feeling of "foreignness"—which people experience in their first social interaction with someone from another culture—might partly serve an evolutionary function: 'Group living surrounds one with individuals [who are] able to physically harm fellow group members, to spread contagious disease, or to "free ride" on their efforts'; therefore, a commitment to sociality is a risk: 'If threats, such as these, are left unchecked, the costs of sociality will quickly exceed its benefits. Thus, to maximize the returns on group "living", individual group members should be attuned to others’ features or behaviors.'Therefore, people who possess the social traits common to the cultural group are to be trusted, and people without the common social traits are to be distrusted as ‘others’, and thus treated with suspicion or excluded from the group. That pressure of social exclusivity, born from the shift towards communal living, excluded uncooperative people and persons with poor personal hygiene. The threat of social exclusion led people to avoid personal behaviours that might embarrass the group or that might provoke revulsion among the group.To demonstrate the transmission of social conformity, the anthropologists Joseph Henrich and Robert Boyd developed a behavioural model indicating that manners are a means of mitigating social differences, curbing undesirable personal behaviours, and fostering co-operation within the social group. That natural selection has favoured the acquisition of genetically-transmitted mechanisms for learning, thereby increasing a person's chances for acquiring locally adaptive behaviours: “Humans possess a reliably developing neural encoding that compels them both to punish individuals who violate group norms (common beliefs or practices) and [to] punish individuals who do not punish norm-violators.”Categories Social manners are in three categories: (i) manners of hygiene, (ii) manners of courtesy, and (iii) manners of cultural norm, each category accounts for an aspect of the functional role that manners play in a society. The categories of manners are based upon the social outcome of behaviour, rather than upon the personal motivation of the behaviour. As a means of social management, the rules of etiquette encompass most aspects of human social interaction; thus, a rule of etiquette reflects an underlying ethical code, and can reflect a person's fashion and social status.(i) Manners of hygiene concern avoiding the transmission of disease, and usually are taught by the parent to the child by way of parental discipline, positive behavioural enforcement of body-fluid continence (toilet training), and the avoidance of and removal of disease vectors that risk the health of children. To that effect, society expects that, by adulthood, the manners for personal hygiene have become a second-nature behaviour, the violations of which shall provoke physical and moral disgust. Hygiene etiquette during the COVID-19 pandemic has included social distancing and warnings against public spitting.(ii) Manners of courtesy concern self-control and good-faith behaviour, by which a person gives priority to the interests of another person, and priority to the interests of a socio-cultural group, in order to be a trusted member of that group. Courtesy manners maximize the benefits of group-living by regulating the nature of social interactions; however, the performance of courtesy manners occasionally interferes with the avoidance of communicable disease. Generally, parents teach courtesy manners in the same way they teach hygiene manners, but the child also learns manners directly (by observing the behaviour of other people in their social interactions) and by imagined social interactions (through the executive functions of the brain). A child usually learns courtesy manners at an older age than when he or she was toilet trained (taught hygiene manners), because learning the manners of courtesy requires that the child be self-aware and conscious of social position, which then facilitate understanding that violations (accidental or deliberate) of social courtesy will provoke peer disapproval within the social group. (iii) Manners of cultural norms concern the social rules by which a person establishes his and her identity and membership to a given socio-cultural group. In abiding the manners of cultural norm, a person demarcates socio-cultural identity and establishes social boundaries, which then identify whom to trust and whom to distrust as 'the other', who is not the self. Cultural norm manners are learnt through the enculturation with and the routinisation of ‘the familiar’, and through social exposure to the ‘cultural otherness’ of people identified as foreign to the group. Transgressions and flouting of the manners of cultural norm usually result in the social alienation of the transgressor. The nature of culture-norm manners allows a high level of intra-group variability, but the manners usually are common to the people who identify with the given socio-cultural group.

Etiquette () is the set of norms of personal behaviour in polite society, usually occurring in the form of an ethical code of the expected and accepted social behaviours that accord with the conventions and norms observed and practised by a society, a social class, or a social group. In modern English usage, the French word étiquette (label and tag) dates from the year 1750.Politeness In the 18th century, during the Age of Enlightenment, the adoption of etiquette was a self-conscious process for acquiring the conventions of politeness and the normative behaviours (charm, manners, demeanour) which symbolically identified the person as a genteel member of the upper class. To identify with the social élite, the upwardly mobile middle class and the bourgeoisie adopted the behaviours and the artistic preferences of the upper class. To that end, socially ambitious people of the middle classes occupied themselves with learning, knowing, and practising the rules of social etiquette, such as the arts of elegant dress and gracious conversation, when to show emotion, and courtesy with and towards women.In the early 18th century, Anthony Ashley-Cooper, 3rd Earl of Shaftesbury, wrote influential essays that defined politeness as the art of being pleasing in company; and discussed the function and nature of politeness in the social discourse of a commercial society:

Etiquette () is the set of norms of personal behaviour in polite society, usually occurring in the form of an ethical code of the expected and accepted social behaviours that accord with the conventions and norms observed and practised by a society, a social class, or a social group. In modern English usage, the French word étiquette (label and tag) dates from the year 1750.Politeness In the 18th century, during the Age of Enlightenment, the adoption of etiquette was a self-conscious process for acquiring the conventions of politeness and the normative behaviours (charm, manners, demeanour) which symbolically identified the person as a genteel member of the upper class. To identify with the social élite, the upwardly mobile middle class and the bourgeoisie adopted the behaviours and the artistic preferences of the upper class. To that end, socially ambitious people of the middle classes occupied themselves with learning, knowing, and practising the rules of social etiquette, such as the arts of elegant dress and gracious conversation, when to show emotion, and courtesy with and towards women.In the early 18th century, Anthony Ashley-Cooper, 3rd Earl of Shaftesbury, wrote influential essays that defined politeness as the art of being pleasing in company; and discussed the function and nature of politeness in the social discourse of a commercial society:

Social forgetting Psychologists have called attention to "social aspects of forgetting". Though often loosely defined, social amnesia is generally considered to be the opposite of collective memory. "Social amnesia" was first discussed by Russell Jacoby, yet his use of the term was restricted to a narrow approach, which was limited to what he perceived to be a relative neglect of psychoanalytical theory in psychology. The cultural historian Peter Burke suggested that "it may be worth investigating the social organization of forgetting, the rules of exclusion, suppression or repression, and the question of who wants whom to forget what". In an in-depth historical study spanning two centuries, Guy Beiner proposed the term "social forgetting", which he distinguished from crude notions of "collective amnesia" and "total oblivion", arguing that "social forgetting is to be found in the interface of public silence and more private remembrance". The philosopher Walter Benjamin sees social forgetting closely linked to the question of present-day interests, arguing that “every image of the past that is not recognized by the present as one of its own concerns threatens to disappear irretrievably”. Building on this, the sociologist David Leupold argued in the context of competing national narratives that what is suppressed and forgotten in one national narrative "might appear at the core of past narrations by the other" - thus often leading to diametrically opposed, mutually exclusive accounts on the past.

Forgetting or disremembering is the apparent loss or modification of information already encoded and stored in an individual's short or long-term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. Problems with remembering, learning and retaining new information are a few of the most common complaints of older adults. Studies show that retention improves with increased rehearsal. This improvement occurs because rehearsal helps to transfer information into long-term memory.Forgetting curves (amount remembered as a function of time since an event was first experienced) have been extensively analyzed. The most recent evidence suggests that a power function provides the closest mathematical fit to the forgetting function.

Forgetting or disremembering is the apparent loss or modification of information already encoded and stored in an individual's short or long-term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. Problems with remembering, learning and retaining new information are a few of the most common complaints of older adults. Studies show that retention improves with increased rehearsal. This improvement occurs because rehearsal helps to transfer information into long-term memory.Forgetting curves (amount remembered as a function of time since an event was first experienced) have been extensively analyzed. The most recent evidence suggests that a power function provides the closest mathematical fit to the forgetting function.Social forgetting Psychologists have called attention to "social aspects of forgetting". Though often loosely defined, social amnesia is generally considered to be the opposite of collective memory. "Social amnesia" was first discussed by Russell Jacoby, yet his use of the term was restricted to a narrow approach, which was limited to what he perceived to be a relative neglect of psychoanalytical theory in psychology. The cultural historian Peter Burke suggested that "it may be worth investigating the social organization of forgetting, the rules of exclusion, suppression or repression, and the question of who wants whom to forget what". In an in-depth historical study spanning two centuries, Guy Beiner proposed the term "social forgetting", which he distinguished from crude notions of "collective amnesia" and "total oblivion", arguing that "social forgetting is to be found in the interface of public silence and more private remembrance". The philosopher Walter Benjamin sees social forgetting closely linked to the question of present-day interests, arguing that “every image of the past that is not recognized by the present as one of its own concerns threatens to disappear irretrievably”. Building on this, the sociologist David Leupold argued in the context of competing national narratives that what is suppressed and forgotten in one national narrative "might appear at the core of past narrations by the other" - thus often leading to diametrically opposed, mutually exclusive accounts on the past.

Organic causes Forgetting that occurs through physiological damage or dilapidation to the brain are referred to as organic causes of forgetting. These theories encompass the loss of information already retained in long-term memory or the inability to encode new information again. Examples include Alzheimer's, amnesia, dementia, consolidation theory and the gradual slowing down of the central nervous system due to aging.Interference theories Interference theory refers to the idea that when the learning of something new causes forgetting of older material on the basis of competition between the two. This essentially states that memory's information may become confused or combined with other information during encoding, resulting in the distortion or disruption of memories. In nature, the interfering items are said to originate from an overstimulating environment. Interference theory exists in three branches: Proactive, Retroactive and Output. Retroactive and Proactive inhibition each referring in contrast to the other. Retroactive interference is when new information (memories) interferes with older information. On the other hand, proactive interference is when old information interferes with the retrieval of new information. This is sometimes thought to occur especially when memories are similar. Output Interference occurs when the initial act of recalling specific information interferes with the retrieval of the original information. Another reason why retrieval failure occurs is due to encoding failure. The information never made it to long-term memory storage. According to the level of processing theory, how well information is encoded depends on the level of processing a piece of information receives. Certain parts of information are better encoded than others; for example, information this visual imagery or that has a survival value is more easily transferred to the long-term memory storage. This theory shows a contradiction: an extremely intelligent individual is expected to forget more hastily than one who has a slow mentality. For this reason, an intelligent individual has stored up more memory in his mind which will cause interferences and impair their ability to recall specific information. Based on current research, testing interference has only been carried out by recalling from a list of words rather than using situation from daily lives, thus it's hard to generalize the findings for this theory. It has been found that interference related tasks decreased memory performance by up to 20%, with negative effects at all interference time points and large variability between participants concerning both the time point and the size of maximal interference. Furthermore, fast learners seem to be more affected by interference than slow learners. People are also less likely to recall items when intervening stimuli are presented within the first ten minutes after learning. Recall performance is better without interference. Peripheral processes such as encoding time, recognition memory and motor execution decline with age. However proactive interference is similar. Suggesting contrary to earlier reports that the inhibitory processes observed with this paradigm remain intact in older adults.

Organic causes Forgetting that occurs through physiological damage or dilapidation to the brain are referred to as organic causes of forgetting. These theories encompass the loss of information already retained in long-term memory or the inability to encode new information again. Examples include Alzheimer's, amnesia, dementia, consolidation theory and the gradual slowing down of the central nervous system due to aging.

Forgetting or disremembering is the apparent loss or modification of information already encoded and stored in an individual's short or long-term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. Problems with remembering, learning and retaining new information are a few of the most common complaints of older adults. Studies show that retention improves with increased rehearsal. This improvement occurs because rehearsal helps to transfer information into long-term memory.Forgetting curves (amount remembered as a function of time since an event was first experienced) have been extensively analyzed. The most recent evidence suggests that a power function provides the closest mathematical fit to the forgetting function.

Forgetting or disremembering is the apparent loss or modification of information already encoded and stored in an individual's short or long-term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. Problems with remembering, learning and retaining new information are a few of the most common complaints of older adults. Studies show that retention improves with increased rehearsal. This improvement occurs because rehearsal helps to transfer information into long-term memory.Forgetting curves (amount remembered as a function of time since an event was first experienced) have been extensively analyzed. The most recent evidence suggests that a power function provides the closest mathematical fit to the forgetting function.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.Causes Road incidents are caused by a large number of human factors such as failing to act according to weather conditions, road design, signage, speed limits, lighting conditions, pavement markings, and roadway obstacles. A 1985 study by K. Rumar, using British and American crash reports as data, suggested 57% of crashes were due solely to driver factors, 27% to combined roadway and driver factors, 6% to combined vehicle and driver factors, 3% solely to roadway factors, 3% to combined roadway, driver, and vehicle factors, 2% solely to vehicle factors, and 1% to combined roadway and vehicle factors. Reducing the severity of injury in crashes is more important than reducing incidence and ranking incidence by broad categories of causes is misleading regarding severe injury reduction. Vehicle and road modifications are generally more effective than behavioral change efforts with the exception of certain laws such as required use of seat belts, motorcycle helmets, and graduated licensing of teenagers.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.Health effects Physical A number of physical injuries can commonly result from the blunt force trauma caused by a collision, ranging from bruising and contusions to catastrophic physical injury (e.g., paralysis), traumatic or non-traumatic cardiac arrest and death. The CDC estimates that roughly 100 people die in motor vehicle crashes each day in the United States.Center of gravitySome crash types tend to have more serious consequences. Rollovers have become more common in recent years, perhaps due to increased popularity of taller SUVs, people carriers, and minivans, which have a higher center of gravity than standard passenger cars. Rollovers can be fatal, especially if the occupants are ejected because they were not wearing seat belts (83% of ejections during rollovers were fatal when the driver did not wear a seat belt, compared to 25% when they did). After a new design of Mercedes Benz notoriously failed a 'moose test' (sudden swerving to avoid an obstacle), some manufacturers enhanced suspension using stability control linked to an anti-lock braking system to reduce the likelihood of rollover. After retrofitting these systems to its models in 1999–2000, Mercedes saw its models involved in fewer crashes.Now, about 40% of new US vehicles, mainly the SUVs, vans and pickup trucks that are more susceptible to rollover, are being produced with a lower center of gravity and enhanced suspension with stability control linked to its anti-lock braking system to reduce the risk of rollover and meet US federal requirements that mandate anti-rollover technology by September 2011. MotorcyclesMotorcyclists and pillion-riders have little protection other than their clothing and helmets. This difference is reflected in the casualty statistics, where they are more than twice as likely to suffer severely after a collision. In 2005, there were 198,735 road crashes with 271,017 reported casualties on roads in Great Britain. This included 3,201 deaths (1.1%) and 28,954 serious injuries (10.7%) overall. Of these casualties 178,302 (66%) were car users and 24,824 (9%) were motorcyclists, of whom 569 were killed (2.3%) and 5,939 seriously injured (24%).Society and culture Economic costs The global economic cost of MVCs was estimated at $518 billion per year in 2003, and $100 billion in developing countries. The Centers for Disease Control and Prevention estimated the U.S. cost in 2000 at $230 billion. A 2010 US report estimated costs of $277 billion, which included lost productivity, medical costs, legal and court costs, emergency service costs (EMS), insurance administration costs, congestion costs, property damage, and workplace losses. "The value of societal harm from motor vehicle crashes, which includes both economic impacts and valuation for lost quality-of-life, was $870.8 billion in 2010. Sixty-eight percent of this value represents lost quality-of-life, while 32 percent are economic impacts."Traffic collision affect the national economy as the cost of road injuries are estimated to account for 1.0% to 2.0% of the gross national product (GNP) of every country each year. A recent study from Nepal showed that the total economic costs of road injuries were approximately $122.88 million, equivalent to 1.52% of the total Nepal GNP for 2017, indicating the growing national financial burden associate with preventable road injuries and deaths.The economic cost to the individuals involved in an MVC varies widely depending on geographic distribution, and varies largely on depth of accident insurance cover, and legislative policy. In the UK for example, a survey conducted using 500 post-accident insurance policy customers, showed an average individual financial loss of £1300.00. This is due in part to voluntary excesses that are common tactics used to reduce overall premium, and in part due to under valuation of vehicles. By contrast, Australian insurance policy holders are subject to an average financial loss of $950.00 AUD.United States Motor vehicle crashes are the leading cause of death in the workplace in the United States accounting for 35 percent of all workplace fatalities. In the United States, individuals involved in motor vehicle collisions may be held financially liable for the consequences of a collision, including property damage, and injuries to passengers and drivers. Where another driver's vehicle is damaged as the result of a crash, some states allow the owner of the vehicle to recover both the cost of repair for the diminished value of the vehicle from the at-fault driver. Because the financial liability that results from causing a crash is so high, most U.S. states require drivers to carry liability insurance to cover these potential costs. In the event of serious injuries or fatalities, it is possible for injured persons to seek compensation in excess of the at-fault driver's insurance coverage.However, liability rules vary from state to state, with some state laws adopting a tort system and others a no-fault insurance system. Most states in the U.S. use a tort-based system, where injured people seek financial compensation from the at-fault parties' insurance carriers. Twelve states take the no-fault approach, where injured parties file their primary claims with their own insurer.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.Society and culture Economic costs The global economic cost of MVCs was estimated at $518 billion per year in 2003, and $100 billion in developing countries. The Centers for Disease Control and Prevention estimated the U.S. cost in 2000 at $230 billion. A 2010 US report estimated costs of $277 billion, which included lost productivity, medical costs, legal and court costs, emergency service costs (EMS), insurance administration costs, congestion costs, property damage, and workplace losses. "The value of societal harm from motor vehicle crashes, which includes both economic impacts and valuation for lost quality-of-life, was $870.8 billion in 2010. Sixty-eight percent of this value represents lost quality-of-life, while 32 percent are economic impacts."Traffic collision affect the national economy as the cost of road injuries are estimated to account for 1.0% to 2.0% of the gross national product (GNP) of every country each year. A recent study from Nepal showed that the total economic costs of road injuries were approximately $122.88 million, equivalent to 1.52% of the total Nepal GNP for 2017, indicating the growing national financial burden associate with preventable road injuries and deaths.The economic cost to the individuals involved in an MVC varies widely depending on geographic distribution, and varies largely on depth of accident insurance cover, and legislative policy. In the UK for example, a survey conducted using 500 post-accident insurance policy customers, showed an average individual financial loss of £1300.00. This is due in part to voluntary excesses that are common tactics used to reduce overall premium, and in part due to under valuation of vehicles. By contrast, Australian insurance policy holders are subject to an average financial loss of $950.00 AUD.United States Motor vehicle crashes are the leading cause of death in the workplace in the United States accounting for 35 percent of all workplace fatalities. In the United States, individuals involved in motor vehicle collisions may be held financially liable for the consequences of a collision, including property damage, and injuries to passengers and drivers. Where another driver's vehicle is damaged as the result of a crash, some states allow the owner of the vehicle to recover both the cost of repair for the diminished value of the vehicle from the at-fault driver. Because the financial liability that results from causing a crash is so high, most U.S. states require drivers to carry liability insurance to cover these potential costs. In the event of serious injuries or fatalities, it is possible for injured persons to seek compensation in excess of the at-fault driver's insurance coverage.However, liability rules vary from state to state, with some state laws adopting a tort system and others a no-fault insurance system. Most states in the U.S. use a tort-based system, where injured people seek financial compensation from the at-fault parties' insurance carriers. Twelve states take the no-fault approach, where injured parties file their primary claims with their own insurer.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.

Legal consequences There are a number of possible legal consequences for causing a traffic collision, including:Traffic citations: drivers who are involved in a collision may receive one or more traffic citations for improper driving conduct such as speeding, failure to obey a traffic control device, or driving under the influence of drugs or alcohol. Convictions for traffic violations are usually penalized with fines, and for more severe offenses, the suspension or revocation of driving privileges. Civil lawsuits: a driver who causes a traffic collision may be sued for damages resulting from the collision, including damages to property and injuries to other persons. Companies can be held liable if their employees cause motor vehicle crashes under a theory of vicarious liability. Other times, injured people can file a product liability lawsuit against a company that designed or distributed a dangerous vehicle or car part. Criminal prosecution: More severe driving misconduct, including impaired driving, may result in criminal charges against the driver. In the event of a fatality, a charge of vehicular homicide is occasionally prosecuted, especially in cases involving alcohol. Convictions for alcohol offenses may result in the revocation or long term suspension of the driver's license, and sometimes jail time, mandatory drug or alcohol rehabilitation, or both.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.Health effects Physical A number of physical injuries can commonly result from the blunt force trauma caused by a collision, ranging from bruising and contusions to catastrophic physical injury (e.g., paralysis), traumatic or non-traumatic cardiac arrest and death. The CDC estimates that roughly 100 people die in motor vehicle crashes each day in the United States.

Vehicle design and maintenance Seat beltsResearch has shown that, across all collision types, it is less likely that seat belts were worn in collisions involving death or serious injury, rather than light injury; wearing a seat belt reduces the risk of death by about 45 percent. Seat belt use is controversial, with notable critics such as Professor John Adams suggesting that their use may lead to a net increase in road casualties due to a phenomenon known as risk compensation. However, actual observation of driver behaviors before and after seat belt laws does not support the risk compensation hypothesis. Several important driving behaviors were observed on the road before and after the belt use law was enforced in Newfoundland, and in Nova Scotia during the same period without a law. Belt use increased from 16 percent to 77 percent in Newfoundland and remained virtually unchanged in Nova Scotia. Four driver behaviors (speed, stopping at intersections when the control light was amber, turning left in front of oncoming traffic, and gaps in following distance) were measured at various sites before and after the law. Changes in these behaviors in Newfoundland were similar to those in Nova Scotia, except that drivers in Newfoundland drove slower on expressways after the law, contrary to the risk compensation theory. MaintenanceA well-designed and well-maintained vehicle, with good brakes, tires and well-adjusted suspension will be more controllable in an emergency and thus be better equipped to avoid collisions. Some mandatory vehicle inspection schemes include tests for some aspects of roadworthiness, such as the UK's MOT test or German TÜV conformance inspection. The design of vehicles has also evolved to improve protection after collision, both for vehicle occupants and for those outside of the vehicle. Much of this work was led by automotive industry competition and technological innovation, leading to measures such as Saab's safety cage and reinforced roof pillars of 1946, Ford's 1956 Lifeguard safety package, and Saab and Volvo's introduction of standard fit seatbelts in 1959. Other initiatives were accelerated as a reaction to consumer pressure, after publications such as Ralph Nader's 1965 book Unsafe at Any Speed accused motor manufacturers of indifference towards safety. In the early 1970s, British Leyland started an intensive programme of vehicle safety research, producing a number of prototype experimental safety vehicles demonstrating various innovations for occupant and pedestrian protection such as air bags, anti-lock brakes, impact-absorbing side-panels, front and rear head restraints, run-flat tires, smooth and deformable front-ends, impact-absorbing bumpers, and retractable headlamps. Design has also been influenced by government legislation, such as the Euro NCAP impact test. Common features designed to improve safety include thicker pillars, safety glass, interiors with no sharp edges, stronger bodies, other active or passive safety features, and smooth exteriors to reduce the consequences of an impact with pedestrians. The UK Department for Transport publish road casualty statistics for each type of collision and vehicle through its Road Casualties Great Britain report. These statistics show a ten to one ratio of in-vehicle fatalities between types of car. In most cars, occupants have a 2–8% chance of death in a two-car collision.However, tort reform has changed the legal landscape. For example, Michigan had a unique no-fault system that guaranteed lifetime benefits for people injured in motor vehicle collisions. This changed in 2020, when the state legislature amended the laws, allowing people to opt for less coverage. While the aim of these laws is to reduce the cost of insurance premiums, catastrophically injured claimants might find themselves underinsured. In some cases, involving a defect in the design or manufacture of motor vehicles, such as where defective design results in SUV rollovers or sudden unintended acceleration, crashes caused by defective tires, or where injuries are caused or worsened as a result of defective airbags, it is possible that the manufacturer will face a class action lawsuit.

Human factors Human factors in vehicle collisions include anything related to drivers and other road users that may contribute to a collision. Examples include driver behavior, visual and auditory acuity, decision-making ability, and reaction speed. A 1985 report based on British and American crash data found driver error, intoxication, and other human factors contribute wholly or partly to about 93% of crashes. A 2019 report from the U.S. National Highway Traffic Safety Administration found that leading contributing factors for fatal crashes included driving too fast for conditions or in excess of the speed limit, operating under the influence, failure to yield right of way, failure to keep within the proper lane, operating a vehicle in a careless manner, and distracted driving.Drivers distracted by mobile devices had nearly four times greater risk of crashing their cars than those who were not. Research from the Virginia Tech Transportation Institute has found that drivers who are texting while driving are 23 times more likely to be involved in a crash as non-texting drivers. Dialing a phone is the most dangerous distraction, increasing a drivers' chance of crashing by 12 times, followed by reading or writing, which increased the risk by ten times.An RAC survey of British drivers found 78% of drivers thought they were highly skilled at driving, and most thought they were better than other drivers, a result suggesting overconfidence in their abilities. Nearly all drivers who had been in a crash did not believe themselves to be at fault. One survey of drivers reported that they thought the key elements of good driving were: controlling a car including a good awareness of the car's size and capabilities reading and reacting to road conditions, weather, road signs, and the environment alertness, reading and anticipating the behavior of other drivers.Although proficiency in these skills is taught and tested as part of the driving exam, a "good" driver can still be at a high risk of crashing because:Driver impairment Driver impairment describes factors that prevent the driver from driving at their normal level of skill. Common impairments include:Alcohol According to the Government of Canada, coroner reports from 2008 suggested almost 40% of fatally injured drivers consumed some quantity of alcohol before the collision. Physical impairment Poor eyesight and/or physical impairment, with many jurisdictions setting simple sight tests and/or requiring appropriate vehicle modifications before being allowed to drive. Youth Insurance statistics demonstrate a notably higher incidence of collisions and fatalities among drivers aged in their teens or early twenties, with insurance rates reflecting this data. These drivers have the highest incidence of both collisions and fatalities among all driver age groups, a fact that was observed well before the advent of mobile phones.Females in this age group exhibit somewhat lower collision and fatality rates than males but still register well above the median for drivers of all ages. Also within this group, the highest collision incidence rate occurs within the first year of licensed driving. For this reason, many US states have enacted a zero-tolerance policy wherein receiving a moving violation within the first six months to one year of obtaining a license results in automatic license suspension. South Dakota is the only state that allows fourteen-year-olds to obtain drivers' licenses. Old age Old age, with some jurisdictions requiring driver retesting for reaction speed and eyesight after a certain age. Sleep deprivationVarious factors such as fatigue or sleep deprivation might increase the risk, or numbers of hours driving might increase the risk of an incident. 41% of drivers self report having fallen asleep at the wheel.: 41  It is estimated that 15% of fatal crashes involve drowsiness (10% of day time crashes, and 24% of night time crashes). Work factors can increase the risk of drowsy driving such as long or irregular hours or driving at night. Drug use Including some prescription drugs, over the counter drugs (notably antihistamines, opioids and muscarinic antagonists), and illegal drugs. Distraction Research suggests that the driver's attention is affected by distracting sounds such as conversations and operating a mobile phone while driving. Many jurisdictions now restrict or outlaw the use of some types of phone within the car. Recent research conducted by British scientists suggests that music can also have an effect; classical music is considered to be calming, yet too much could relax the driver to a condition of distraction. On the other hand, hard rock may encourage the driver to step on the acceleration pedal, thus creating a potentially dangerous situation on the road.Cell phone use is an increasingly significant problem on the roads and as the U.S. National Safety Council compiled more than 30 studies postulating that hands-free is not a safer option, because the brain remains distracted by the conversation and cannot focus solely on the task of driving.

Driver impairment Driver impairment describes factors that prevent the driver from driving at their normal level of skill. Common impairments include:Alcohol According to the Government of Canada, coroner reports from 2008 suggested almost 40% of fatally injured drivers consumed some quantity of alcohol before the collision. Physical impairment Poor eyesight and/or physical impairment, with many jurisdictions setting simple sight tests and/or requiring appropriate vehicle modifications before being allowed to drive. Youth Insurance statistics demonstrate a notably higher incidence of collisions and fatalities among drivers aged in their teens or early twenties, with insurance rates reflecting this data. These drivers have the highest incidence of both collisions and fatalities among all driver age groups, a fact that was observed well before the advent of mobile phones.Females in this age group exhibit somewhat lower collision and fatality rates than males but still register well above the median for drivers of all ages. Also within this group, the highest collision incidence rate occurs within the first year of licensed driving. For this reason, many US states have enacted a zero-tolerance policy wherein receiving a moving violation within the first six months to one year of obtaining a license results in automatic license suspension. South Dakota is the only state that allows fourteen-year-olds to obtain drivers' licenses. Old age Old age, with some jurisdictions requiring driver retesting for reaction speed and eyesight after a certain age. Sleep deprivationVarious factors such as fatigue or sleep deprivation might increase the risk, or numbers of hours driving might increase the risk of an incident. 41% of drivers self report having fallen asleep at the wheel.: 41  It is estimated that 15% of fatal crashes involve drowsiness (10% of day time crashes, and 24% of night time crashes). Work factors can increase the risk of drowsy driving such as long or irregular hours or driving at night. Drug use Including some prescription drugs, over the counter drugs (notably antihistamines, opioids and muscarinic antagonists), and illegal drugs. Distraction Research suggests that the driver's attention is affected by distracting sounds such as conversations and operating a mobile phone while driving. Many jurisdictions now restrict or outlaw the use of some types of phone within the car. Recent research conducted by British scientists suggests that music can also have an effect; classical music is considered to be calming, yet too much could relax the driver to a condition of distraction. On the other hand, hard rock may encourage the driver to step on the acceleration pedal, thus creating a potentially dangerous situation on the road.Cell phone use is an increasingly significant problem on the roads and as the U.S. National Safety Council compiled more than 30 studies postulating that hands-free is not a safer option, because the brain remains distracted by the conversation and cannot focus solely on the task of driving.

Criticism of "accident" terminology Many organizations, companies, and local, state, and federal departments have begun to avoid the term accident, instead preferring terms such as collision, crash or incident. This is because the term accident may imply that there is no one to blame or that the collision was unavoidable, whereas most traffic collisions are the result of driving under the influence, excessive speed, distractions such as mobile phones or other risky behavior, poor road design, or other preventable factors. In 1997, George L. Reagle, the Associate Administrator for Motor Carriers of the Federal Motor Carrier Safety Administration wrote a letter stating that "A crash is not an accident", emphasizing that the Department's Research and Special Programs Administration, the Federal Highway Administration, and the National Highway Traffic Safety Administration had all declared that "accident" should be avoided in their published writings and media communications. In 2016, the Associated Press updated their style guide to recommend that journalists use "crash, collision, or other terms" rather than "accident", unless culpability is proven. The AP also recommends avoiding "accident" when negligence is proven or claimed because the term "can be read as exonerating the person responsible." In 2021, the American Automobile Association (AAA) passed a resolution to replace "car accident" with "car crash" in their vocabulary. In 2022, the traffic management company INRIX announced that "accident" would be removed from their lexicon.The Maryland Department of Transportation's Highway Safety Office emphasizes that "crashes are no accident", saying that "Using the word accident suggests that an incident was unavoidable, but many roadway crashes can be attributed to human error." The Michigan Department of Transportation states that "accident" should be dropped in favor of "crash", saying that "Traffic crashes are fixable problems, caused by inattentive drivers and driver behavior. They are NOT accidents." In line with their Vision Zero commitments, the Portland Bureau of Transportation recommends using "crash" rather than "accident".Historically, in the United States, the use of terms other than accident had been criticized for holding back safety improvements, based on the idea that a culture of blame may discourage the involved parties from fully disclosing the facts, and thus frustrate attempts to address the real root causes.Human factors Human factors in vehicle collisions include anything related to drivers and other road users that may contribute to a collision. Examples include driver behavior, visual and auditory acuity, decision-making ability, and reaction speed. A 1985 report based on British and American crash data found driver error, intoxication, and other human factors contribute wholly or partly to about 93% of crashes. A 2019 report from the U.S. National Highway Traffic Safety Administration found that leading contributing factors for fatal crashes included driving too fast for conditions or in excess of the speed limit, operating under the influence, failure to yield right of way, failure to keep within the proper lane, operating a vehicle in a careless manner, and distracted driving.Drivers distracted by mobile devices had nearly four times greater risk of crashing their cars than those who were not. Research from the Virginia Tech Transportation Institute has found that drivers who are texting while driving are 23 times more likely to be involved in a crash as non-texting drivers. Dialing a phone is the most dangerous distraction, increasing a drivers' chance of crashing by 12 times, followed by reading or writing, which increased the risk by ten times.An RAC survey of British drivers found 78% of drivers thought they were highly skilled at driving, and most thought they were better than other drivers, a result suggesting overconfidence in their abilities. Nearly all drivers who had been in a crash did not believe themselves to be at fault. One survey of drivers reported that they thought the key elements of good driving were: controlling a car including a good awareness of the car's size and capabilities reading and reacting to road conditions, weather, road signs, and the environment alertness, reading and anticipating the behavior of other drivers.Although proficiency in these skills is taught and tested as part of the driving exam, a "good" driver can still be at a high risk of crashing because:Alcohol According to the Government of Canada, coroner reports from 2008 suggested almost 40% of fatally injured drivers consumed some quantity of alcohol before the collision. Physical impairment Poor eyesight and/or physical impairment, with many jurisdictions setting simple sight tests and/or requiring appropriate vehicle modifications before being allowed to drive. Youth Insurance statistics demonstrate a notably higher incidence of collisions and fatalities among drivers aged in their teens or early twenties, with insurance rates reflecting this data. These drivers have the highest incidence of both collisions and fatalities among all driver age groups, a fact that was observed well before the advent of mobile phones.Females in this age group exhibit somewhat lower collision and fatality rates than males but still register well above the median for drivers of all ages. Also within this group, the highest collision incidence rate occurs within the first year of licensed driving. For this reason, many US states have enacted a zero-tolerance policy wherein receiving a moving violation within the first six months to one year of obtaining a license results in automatic license suspension. South Dakota is the only state that allows fourteen-year-olds to obtain drivers' licenses. Old age Old age, with some jurisdictions requiring driver retesting for reaction speed and eyesight after a certain age. Sleep deprivationVarious factors such as fatigue or sleep deprivation might increase the risk, or numbers of hours driving might increase the risk of an incident. 41% of drivers self report having fallen asleep at the wheel.: 41  It is estimated that 15% of fatal crashes involve drowsiness (10% of day time crashes, and 24% of night time crashes). Work factors can increase the risk of drowsy driving such as long or irregular hours or driving at night. Drug use Including some prescription drugs, over the counter drugs (notably antihistamines, opioids and muscarinic antagonists), and illegal drugs. Distraction Research suggests that the driver's attention is affected by distracting sounds such as conversations and operating a mobile phone while driving. Many jurisdictions now restrict or outlaw the use of some types of phone within the car. Recent research conducted by British scientists suggests that music can also have an effect; classical music is considered to be calming, yet too much could relax the driver to a condition of distraction. On the other hand, hard rock may encourage the driver to step on the acceleration pedal, thus creating a potentially dangerous situation on the road.Cell phone use is an increasingly significant problem on the roads and as the U.S. National Safety Council compiled more than 30 studies postulating that hands-free is not a safer option, because the brain remains distracted by the conversation and cannot focus solely on the task of driving.

Terminology Traffic collisions can be classified by general types. Types of collision include head-on, road departure, rear-end, side collisions, and rollovers. Many different terms are commonly used to describe vehicle collisions. The World Health Organization uses the term road traffic injury, while the U.S. Census Bureau uses the term motor vehicle accidents (MVA), and Transport Canada uses the term "motor vehicle traffic collision" (MVTC). Other common terms include auto accident, car accident, car crash, car smash, car wreck, motor vehicle collision (MVC), personal injury collision (PIC), road accident, road traffic accident (RTA), road traffic collision (RTC), and road traffic incident (RTI) as well as more unofficial terms including smash-up, pile-up, and fender bender.

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.Criticism of "accident" terminology Many organizations, companies, and local, state, and federal departments have begun to avoid the term accident, instead preferring terms such as collision, crash or incident. This is because the term accident may imply that there is no one to blame or that the collision was unavoidable, whereas most traffic collisions are the result of driving under the influence, excessive speed, distractions such as mobile phones or other risky behavior, poor road design, or other preventable factors. In 1997, George L. Reagle, the Associate Administrator for Motor Carriers of the Federal Motor Carrier Safety Administration wrote a letter stating that "A crash is not an accident", emphasizing that the Department's Research and Special Programs Administration, the Federal Highway Administration, and the National Highway Traffic Safety Administration had all declared that "accident" should be avoided in their published writings and media communications. In 2016, the Associated Press updated their style guide to recommend that journalists use "crash, collision, or other terms" rather than "accident", unless culpability is proven. The AP also recommends avoiding "accident" when negligence is proven or claimed because the term "can be read as exonerating the person responsible." In 2021, the American Automobile Association (AAA) passed a resolution to replace "car accident" with "car crash" in their vocabulary. In 2022, the traffic management company INRIX announced that "accident" would be removed from their lexicon.The Maryland Department of Transportation's Highway Safety Office emphasizes that "crashes are no accident", saying that "Using the word accident suggests that an incident was unavoidable, but many roadway crashes can be attributed to human error." The Michigan Department of Transportation states that "accident" should be dropped in favor of "crash", saying that "Traffic crashes are fixable problems, caused by inattentive drivers and driver behavior. They are NOT accidents." In line with their Vision Zero commitments, the Portland Bureau of Transportation recommends using "crash" rather than "accident".Historically, in the United States, the use of terms other than accident had been criticized for holding back safety improvements, based on the idea that a culture of blame may discourage the involved parties from fully disclosing the facts, and thus frustrate attempts to address the real root causes.Combinations of factors Several conditions can combine to create a much worse situation, for example:

A traffic collision, also called a motor vehicle collision (car crash in case cars are involved in the collision), occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term.A number of factors contribute to the risk of collisions, including vehicle design, speed of operation, road design, weather, road environment, driving skills, impairment due to alcohol or drugs, and behavior, notably aggressive driving, distracted driving, speeding and street racing.

Intent Some traffic collisions are caused intentionally by a driver. For example, a collision may be caused by a driver who intends to commit vehicular suicide. Collisions may also be intentionally caused by people who hope to make an insurance claim against the other driver, or may be staged for such purposes as insurance fraud. Motor vehicles may also be involved in collisions as part of a deliberate effort to hurt other people, such as in a vehicle-ramming attack.

Legal consequences There are a number of possible legal consequences for causing a traffic collision, including:Traffic citations: drivers who are involved in a collision may receive one or more traffic citations for improper driving conduct such as speeding, failure to obey a traffic control device, or driving under the influence of drugs or alcohol. Convictions for traffic violations are usually penalized with fines, and for more severe offenses, the suspension or revocation of driving privileges. Civil lawsuits: a driver who causes a traffic collision may be sued for damages resulting from the collision, including damages to property and injuries to other persons. Companies can be held liable if their employees cause motor vehicle crashes under a theory of vicarious liability. Other times, injured people can file a product liability lawsuit against a company that designed or distributed a dangerous vehicle or car part. Criminal prosecution: More severe driving misconduct, including impaired driving, may result in criminal charges against the driver. In the event of a fatality, a charge of vehicular homicide is occasionally prosecuted, especially in cases involving alcohol. Convictions for alcohol offenses may result in the revocation or long term suspension of the driver's license, and sometimes jail time, mandatory drug or alcohol rehabilitation, or both.

A pothole is a depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water first weakens the underlying soil; traffic then fatigues and breaks the poorly supported asphalt surface in the affected area. Continued traffic action ejects both asphalt and the underlying soil material to create a hole in the pavement.

Formation According to the US Army Corps of Engineers's Cold Regions Research and Engineering Laboratory, pothole formation requires two factors to be present at the same time: water and traffic. Water weakens the soil beneath the pavement while traffic applies the loads that stress the pavement past the breaking point. Potholes form progressively from fatigue of the road surface which can lead to a precursor failure pattern known as crocodile (or alligator) cracking. Eventually, chunks of pavement between the fatigue cracks gradually work loose, and may then be plucked or forced out of the surface by continued wheel loads to create a pothole.In areas subject to freezing and thawing, frost heaving can damage a pavement and create openings for water to enter. In the spring, thaw of pavements accelerates this process when the thawing of upper portions of the soil structure in a pavement cannot drain past still-frozen lower layers, thus saturating the supporting soil and weakening it.Potholes can grow to several feet in width, though they usually only develop to depths of a few inches. If they become large enough, damage to tires, wheels, and vehicle suspensions is liable to occur. Serious road accidents can occur as a direct result, especially on those roads where vehicle speeds are greater.Potholes may result from four main causes: 1. Insufficient pavement thickness to support traffic during freeze/thaw periods without localized failures 2. Insufficient drainage 3. Failures at utility trenches and castings (manhole and drain casings) 4. Pavement defects and cracks left unmaintained and unsealed so as to admit moisture and compromise the structural integrity of the pavement

A pothole is a depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water first weakens the underlying soil; traffic then fatigues and breaks the poorly supported asphalt surface in the affected area. Continued traffic action ejects both asphalt and the underlying soil material to create a hole in the pavement.Formation According to the US Army Corps of Engineers's Cold Regions Research and Engineering Laboratory, pothole formation requires two factors to be present at the same time: water and traffic. Water weakens the soil beneath the pavement while traffic applies the loads that stress the pavement past the breaking point. Potholes form progressively from fatigue of the road surface which can lead to a precursor failure pattern known as crocodile (or alligator) cracking. Eventually, chunks of pavement between the fatigue cracks gradually work loose, and may then be plucked or forced out of the surface by continued wheel loads to create a pothole.In areas subject to freezing and thawing, frost heaving can damage a pavement and create openings for water to enter. In the spring, thaw of pavements accelerates this process when the thawing of upper portions of the soil structure in a pavement cannot drain past still-frozen lower layers, thus saturating the supporting soil and weakening it.Potholes can grow to several feet in width, though they usually only develop to depths of a few inches. If they become large enough, damage to tires, wheels, and vehicle suspensions is liable to occur. Serious road accidents can occur as a direct result, especially on those roads where vehicle speeds are greater.Potholes may result from four main causes: 1. Insufficient pavement thickness to support traffic during freeze/thaw periods without localized failures 2. Insufficient drainage 3. Failures at utility trenches and castings (manhole and drain casings) 4. Pavement defects and cracks left unmaintained and unsealed so as to admit moisture and compromise the structural integrity of the pavementCosts to the public The American Automobile Association estimated in the five years prior to 2016 that 16 million drivers in the United States have suffered damage from potholes to their vehicle including tire punctures, bent wheels, and damaged suspensions with a cost of $3 billion a year. In India, between 2015 and 2017, an average of 3,000 people per year were killed in accidents involving potholes. Britain has estimated that the cost of fixing all roads with potholes in the country would cost £12 billion.

A pothole is a depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water first weakens the underlying soil; traffic then fatigues and breaks the poorly supported asphalt surface in the affected area. Continued traffic action ejects both asphalt and the underlying soil material to create a hole in the pavement.Formation According to the US Army Corps of Engineers's Cold Regions Research and Engineering Laboratory, pothole formation requires two factors to be present at the same time: water and traffic. Water weakens the soil beneath the pavement while traffic applies the loads that stress the pavement past the breaking point. Potholes form progressively from fatigue of the road surface which can lead to a precursor failure pattern known as crocodile (or alligator) cracking. Eventually, chunks of pavement between the fatigue cracks gradually work loose, and may then be plucked or forced out of the surface by continued wheel loads to create a pothole.In areas subject to freezing and thawing, frost heaving can damage a pavement and create openings for water to enter. In the spring, thaw of pavements accelerates this process when the thawing of upper portions of the soil structure in a pavement cannot drain past still-frozen lower layers, thus saturating the supporting soil and weakening it.Potholes can grow to several feet in width, though they usually only develop to depths of a few inches. If they become large enough, damage to tires, wheels, and vehicle suspensions is liable to occur. Serious road accidents can occur as a direct result, especially on those roads where vehicle speeds are greater.Potholes may result from four main causes: 1. Insufficient pavement thickness to support traffic during freeze/thaw periods without localized failures 2. Insufficient drainage 3. Failures at utility trenches and castings (manhole and drain casings) 4. Pavement defects and cracks left unmaintained and unsealed so as to admit moisture and compromise the structural integrity of the pavement

Medical conditions Osmidrosis or bromhidrosis is defined by a foul odor due to a water-rich environment that supports bacteria, which is caused by an abnormal increase in perspiration (hyperhidrosis). This can be particularly strong when it happens in the axillary region (underarms). In this case, the condition may be referred to as axillary osmidrosis. The condition can also be known medically as apocrine bromhidrosis, ozochrotia, fetid sweat, body smell, or malodorous sweating.Trimethylaminuria (TMAU), also known as fish odor syndrome or fish malodor syndrome, is a rare metabolic disorder where trimethylamine is released in the person's sweat, urine, and breath, giving off a strong fishy odor or strong body odor.

Causes In humans, the formation of body odors is caused by factors such as diet, sex, health, and medication, but the major contribution comes from bacterial activity on skin gland secretions. Humans have three types of sweat glands: eccrine sweat glands, apocrine sweat glands and sebaceous glands. Eccrine sweat glands are present from birth, while the latter two become activated during puberty. Among the different types of human skin glands, body odor is primarily the result of the apocrine sweat glands, which secrete the majority of chemical compounds that the skin flora metabolize into odorant substances. This happens mostly in the axillary (armpit) region, although the gland can also be found in the areola, anogenital region, and around the navel. In humans, the armpit regions seem more important than the genital region for body odor, which may be related to human bipedalism. The genital and armpit regions also contain springy hairs which help diffuse body odors.The main components of human axillary odor are unsaturated or hydroxylated branched fatty acids with E-3-methylhex-2-enoic acid (E-3M2H) and 3-hydroxy-3-methylhexanoic acid (HMHA), sulfanylalkanols and particularly 3-methyl-3-sulfanylhexan-1-ol (3M3SH), and the odoriferous steroids androstenone (5α-androst-16-en-3-one) and androstenol (5α-androst-16-en-3α-ol). E-3M2H is bound and carried by two apocrine secretion odor-binding proteins, ASOB1 and ASOB2, to the skin surface.Body odor is influenced by the actions of the skin flora, including members of Corynebacterium, which manufacture enzymes called lipases that break down the lipids in sweat to create smaller molecules like butyric acid. Greater bacteria populations of Corynebacterium jeikeium are found more in the armpits of men, whereas greater population numbers of Staphylococcus haemolyticus are found in the armpits of women. This causes male armpits to give off a rancid/cheese-like smell, whereas female armpits give off a more fruity/onion-like smell. Staphylococcus hominis is also known for producing thioalcohol compounds that contribute to odors. These smaller molecules smell, and give body odor its characteristic aroma. Propionic acid (propanoic acid) is present in many sweat samples. This acid is a breakdown product of some amino acids by propionibacteria, which thrive in the ducts of adolescent and adult sebaceous glands. Because propionic acid is chemically similar to acetic acid, with similar characteristics including odor, body odors may be identified as having a pungent, cheesy and vinegar-like smell although certain people might find it pleasant at lower concentrations. Isovaleric acid (3-methyl butanoic acid) is the other source of body odor as a result of actions of the bacteria Staphylococcus epidermidis, which is also present in several types of strong cheese. Factors such as food, drink, gut microbiome and diseases can affect body odor, as can lifestyle and genetics.

Humans In humans, body odor serves as a means of chemosensory signal communication between members of the species. These signals are called pheromones and they can be transmitted through a variety of mediums. The most common way that human pheromones are transmitted is through bodily fluids. Human pheromones are contained in sweat, semen, vaginal secretions, breast milk, and urine. The signals carried in these fluids serve a range of functions from reproductive signaling to infant socialization. Each person produces a unique spread of pheromones that can be identified by others. This differentiation allows the formation of sexual attraction and kinship ties to occur.Sebaceous and apocrine glands become active at puberty. This, as well as many apocrine glands being close to the sex organs, points to a role related to mating. Sebaceous glands line the human skin while apocrine glands are located around body hairs. Compared to other primates, humans have extensive axillary hair and have many odor producing sources, in particular many apocrine glands. In humans, the apocrine glands have the ability to secrete pheromones. These steroid compounds are produced within the peroxisomes of the apocrine glands by enzymes such as mevalonate kinases.

Body odor or body odour (BO) is present in all animals and its intensity can be influenced by many factors (behavioral patterns, survival strategies). Body odor has a strong genetic basis, but can also be strongly influenced by various diseases and physiological conditions. Though body odor has played an important role (and continues to do so in many life forms) in early humankind, it is generally considered to be an unpleasant odor amongst many human cultures.

Body odor or body odour (BO) is present in all animals and its intensity can be influenced by many factors (behavioral patterns, survival strategies). Body odor has a strong genetic basis, but can also be strongly influenced by various diseases and physiological conditions. Though body odor has played an important role (and continues to do so in many life forms) in early humankind, it is generally considered to be an unpleasant odor amongst many human cultures.Causes In humans, the formation of body odors is caused by factors such as diet, sex, health, and medication, but the major contribution comes from bacterial activity on skin gland secretions. Humans have three types of sweat glands: eccrine sweat glands, apocrine sweat glands and sebaceous glands. Eccrine sweat glands are present from birth, while the latter two become activated during puberty. Among the different types of human skin glands, body odor is primarily the result of the apocrine sweat glands, which secrete the majority of chemical compounds that the skin flora metabolize into odorant substances. This happens mostly in the axillary (armpit) region, although the gland can also be found in the areola, anogenital region, and around the navel. In humans, the armpit regions seem more important than the genital region for body odor, which may be related to human bipedalism. The genital and armpit regions also contain springy hairs which help diffuse body odors.The main components of human axillary odor are unsaturated or hydroxylated branched fatty acids with E-3-methylhex-2-enoic acid (E-3M2H) and 3-hydroxy-3-methylhexanoic acid (HMHA), sulfanylalkanols and particularly 3-methyl-3-sulfanylhexan-1-ol (3M3SH), and the odoriferous steroids androstenone (5α-androst-16-en-3-one) and androstenol (5α-androst-16-en-3α-ol). E-3M2H is bound and carried by two apocrine secretion odor-binding proteins, ASOB1 and ASOB2, to the skin surface.Body odor is influenced by the actions of the skin flora, including members of Corynebacterium, which manufacture enzymes called lipases that break down the lipids in sweat to create smaller molecules like butyric acid. Greater bacteria populations of Corynebacterium jeikeium are found more in the armpits of men, whereas greater population numbers of Staphylococcus haemolyticus are found in the armpits of women. This causes male armpits to give off a rancid/cheese-like smell, whereas female armpits give off a more fruity/onion-like smell. Staphylococcus hominis is also known for producing thioalcohol compounds that contribute to odors. These smaller molecules smell, and give body odor its characteristic aroma. Propionic acid (propanoic acid) is present in many sweat samples. This acid is a breakdown product of some amino acids by propionibacteria, which thrive in the ducts of adolescent and adult sebaceous glands. Because propionic acid is chemically similar to acetic acid, with similar characteristics including odor, body odors may be identified as having a pungent, cheesy and vinegar-like smell although certain people might find it pleasant at lower concentrations. Isovaleric acid (3-methyl butanoic acid) is the other source of body odor as a result of actions of the bacteria Staphylococcus epidermidis, which is also present in several types of strong cheese. Factors such as food, drink, gut microbiome and diseases can affect body odor, as can lifestyle and genetics.

Diet High dietary intakes of saturated fat, trans-fats and salt, and low intake of fruits, vegetables and fish are linked to cardiovascular risk, although whether all these associations indicate causes is disputed. The World Health Organization attributes approximately 1.7 million deaths worldwide to low fruit and vegetable consumption. Frequent consumption of high-energy foods, such as processed foods that are high in fats and sugars, promotes obesity and may increase cardiovascular risk. The amount of dietary salt consumed may also be an important determinant of blood pressure levels and overall cardiovascular risk. There is moderate quality evidence that reducing saturated fat intake for at least two years reduces the risk of cardiovascular disease. High trans-fat intake has adverse effects on blood lipids and circulating inflammatory markers, and elimination of trans-fat from diets has been widely advocated. In 2018 the World Health Organization estimated that trans fats were the cause of more than half a million deaths per year. There is evidence that higher consumption of sugar is associated with higher blood pressure and unfavorable blood lipids, and sugar intake also increases the risk of diabetes mellitus. High consumption of processed meats is associated with an increased risk of cardiovascular disease, possibly in part due to increased dietary salt intake.

Risk factors There are many risk factors for heart diseases: age, sex, tobacco use, physical inactivity, non-alcoholic fatty liver disease, excessive alcohol consumption, unhealthy diet, obesity, genetic predisposition and family history of cardiovascular disease, raised blood pressure (hypertension), raised blood sugar (diabetes mellitus), raised blood cholesterol (hyperlipidemia), undiagnosed celiac disease, psychosocial factors, poverty and low educational status, air pollution, and poor sleep. While the individual contribution of each risk factor varies between different communities or ethnic groups the overall contribution of these risk factors is very consistent. Some of these risk factors, such as age, sex or family history/genetic predisposition, are immutable; however, many important cardiovascular risk factors are modifiable by lifestyle change, social change, drug treatment (for example prevention of hypertension, hyperlipidemia, and diabetes). People with obesity are at increased risk of atherosclerosis of the coronary arteries.Genetics Cardiovascular disease in a person's parents increases their risk by ~3 fold, and genetics is an important risk factor for cardiovascular diseases. Genetic cardiovascular disease can occur either as a consequence of single variant (Mendelian) or polygenic influences. There are more than 40 inherited cardiovascular disease that can be traced to a single disease-causing DNA variant, although these conditions are rare. Most common cardiovascular diseases are non-Mendelian and are thought to be due to hundreds or thousands of genetic variants (known as single nucleotide polymorphisms), each associated with a small effect.Age Age is the most important risk factor in developing cardiovascular or heart diseases, with approximately a tripling of risk with each decade of life. Coronary fatty streaks can begin to form in adolescence. It is estimated that 82 percent of people who die of coronary heart disease are 65 and older. Simultaneously, the risk of stroke doubles every decade after age 55.Multiple explanations are proposed to explain why age increases the risk of cardiovascular/heart diseases. One of them relates to serum cholesterol level. In most populations, the serum total cholesterol level increases as age increases. In men, this increase levels off around age 45 to 50 years. In women, the increase continues sharply until age 60 to 65 years.Aging is also associated with changes in the mechanical and structural properties of the vascular wall, which leads to the loss of arterial elasticity and reduced arterial compliance and may subsequently lead to coronary artery disease.Sex Men are at greater risk of heart disease than pre-menopausal women. Once past menopause, it has been argued that a woman's risk is similar to a man's although more recent data from the WHO and UN disputes this. If a female has diabetes, she is more likely to develop heart disease than a male with diabetes.Coronary heart diseases are 2 to 5 times more common among middle-aged men than women. In a study done by the World Health Organization, sex contributes to approximately 40% of the variation in sex ratios of coronary heart disease mortality. Another study reports similar results finding that sex differences explains nearly half the risk associated with cardiovascular diseases One of the proposed explanations for sex differences in cardiovascular diseases is hormonal difference. Among women, estrogen is the predominant sex hormone. Estrogen may have protective effects on glucose metabolism and hemostatic system, and may have direct effect in improving endothelial cell function. The production of estrogen decreases after menopause, and this may change the female lipid metabolism toward a more atherogenic form by decreasing the HDL cholesterol level while increasing LDL and total cholesterol levels.Among men and women, there are differences in body weight, height, body fat distribution, heart rate, stroke volume, and arterial compliance. In the very elderly, age-related large artery pulsatility and stiffness are more pronounced among women than men. This may be caused by the women's smaller body size and arterial dimensions which are independent of menopause.

Postterm pregnancy, i.e. if the pregnancy has gone past the end of the 42nd week. Intrauterine fetal growth restriction (IUGR). There are health risks to the woman in continuing the pregnancy (e.g. she has pre-eclampsia). Premature rupture of the membranes (PROM); this is when the membranes have ruptured, but labor does not start within a specific amount of time. Premature termination of the pregnancy (abortion). Fetal death in utero and previous history of stillbirth. Twin pregnancy continuing beyond 38 weeks. Previous health conditions that puts risk on the woman and/or her child such as diabetes, high blood pressure High BMIInduction of labor in those who are either at or after term improves outcomes for newborns and decreases the number of C-sections performed.

Medical uses Commonly accepted medical reasons for induction include:

Postterm pregnancy, i.e. if the pregnancy has gone past the end of the 42nd week. Intrauterine fetal growth restriction (IUGR). There are health risks to the woman in continuing the pregnancy (e.g. she has pre-eclampsia). Premature rupture of the membranes (PROM); this is when the membranes have ruptured, but labor does not start within a specific amount of time. Premature termination of the pregnancy (abortion). Fetal death in utero and previous history of stillbirth. Twin pregnancy continuing beyond 38 weeks. Previous health conditions that puts risk on the woman and/or her child such as diabetes, high blood pressure High BMIInduction of labor in those who are either at or after term improves outcomes for newborns and decreases the number of C-sections performed.

Postterm pregnancy, i.e. if the pregnancy has gone past the end of the 42nd week. Intrauterine fetal growth restriction (IUGR). There are health risks to the woman in continuing the pregnancy (e.g. she has pre-eclampsia). Premature rupture of the membranes (PROM); this is when the membranes have ruptured, but labor does not start within a specific amount of time. Premature termination of the pregnancy (abortion). Fetal death in utero and previous history of stillbirth. Twin pregnancy continuing beyond 38 weeks. Previous health conditions that puts risk on the woman and/or her child such as diabetes, high blood pressure High BMIInduction of labor in those who are either at or after term improves outcomes for newborns and decreases the number of C-sections performed.Criticisms of induction Induced labor may be more painful for the woman as one of the side effects of intravenous oxytocin is increased contraction pains, mainly due to the rigid onset. This may lead to the increased use of analgesics and other pain-relieving pharmaceuticals. These interventions may also lead to an increased likelihood of caesarean section delivery for the baby. However, studies into this matter show differing results. One study indicated that while overall caesarean section rates from 1990 to 1997 remained at or below 20 per cent, elective induction was associated with a doubling of the rate of Caesarean section. Another study showed that elective induction in women who were not post-term increased a woman's chance of a C-section by two to three times. A more recent study indicated that induction may increase the risk of caesarean section if performed before the 40th week of gestation, but it has no effect or actually lowers the risk if performed after the 40th week.A 2014 systematic review and meta analysis on the subject of induction and its effect on cesarean section indicate that after 41 weeks of gestation there is a reduction of cesarean deliveries when the labour is induced.The Institute for Safe Medication Practices labeled pitocin a "high-alert medication" because of the high likelihood of "significant patient harm when it is used in error."

Postterm pregnancy, i.e. if the pregnancy has gone past the end of the 42nd week. Intrauterine fetal growth restriction (IUGR). There are health risks to the woman in continuing the pregnancy (e.g. she has pre-eclampsia). Premature rupture of the membranes (PROM); this is when the membranes have ruptured, but labor does not start within a specific amount of time. Premature termination of the pregnancy (abortion). Fetal death in utero and previous history of stillbirth. Twin pregnancy continuing beyond 38 weeks. Previous health conditions that puts risk on the woman and/or her child such as diabetes, high blood pressure High BMIInduction of labor in those who are either at or after term improves outcomes for newborns and decreases the number of C-sections performed.Criticisms of induction Induced labor may be more painful for the woman as one of the side effects of intravenous oxytocin is increased contraction pains, mainly due to the rigid onset. This may lead to the increased use of analgesics and other pain-relieving pharmaceuticals. These interventions may also lead to an increased likelihood of caesarean section delivery for the baby. However, studies into this matter show differing results. One study indicated that while overall caesarean section rates from 1990 to 1997 remained at or below 20 per cent, elective induction was associated with a doubling of the rate of Caesarean section. Another study showed that elective induction in women who were not post-term increased a woman's chance of a C-section by two to three times. A more recent study indicated that induction may increase the risk of caesarean section if performed before the 40th week of gestation, but it has no effect or actually lowers the risk if performed after the 40th week.A 2014 systematic review and meta analysis on the subject of induction and its effect on cesarean section indicate that after 41 weeks of gestation there is a reduction of cesarean deliveries when the labour is induced.The Institute for Safe Medication Practices labeled pitocin a "high-alert medication" because of the high likelihood of "significant patient harm when it is used in error."

Motivation is the reason for which humans and other animals initiate, continue, or terminate a behavior at a given time. Motivational states are commonly understood as forces acting within the agent that create a disposition to engage in goal-directed behavior. It is often held that different mental states compete with each other and that only the strongest state determines behavior. This means that we can be motivated to do something without actually doing it. The paradigmatic mental state providing motivation is desire. But various other states, such as beliefs about what one ought to do or intentions, may also provide motivation. Motivation is derived from the word 'motive', which denotes a person's needs, desires, wants, or urges. It is the process of motivating individuals to take action in order to achieve a goal. The psychological elements fueling people's behavior in the context of job goals might include a desire for money. Various competing theories have been proposed concerning the content of motivational states. They are known as content theories and aim to describe what goals usually or always motivate people. Abraham Maslow's hierarchy of needs and the ERG theory, for example, posit that humans have certain needs, which are responsible for motivation. Some of these needs, like for food and water, are more basic than other needs, such as for respect from others. On this view, the higher needs can only provide motivation once the lower needs have been fulfilled. Behaviorist theories try to explain behavior solely in terms of the relation between the situation and external, observable behavior without explicit reference to conscious mental states. Motivation may be either intrinsic, if the activity is desired because it is inherently interesting or enjoyable, or extrinsic, if the agent's goal is an external reward distinct from the activity itself. It has been argued that intrinsic motivation has more beneficial outcomes than extrinsic motivation. Motivational states can also be categorized according to whether the agent is fully aware of why he acts the way he does or not, referred to as conscious and unconscious motivation. Motivation is closely related to practical rationality. A central idea in this field is that we should be motivated to perform an action if we believe that we should perform it. Failing to fulfill this requirement results in cases of irrationality, known as akrasia or weakness of the will, in which there is a discrepancy between our beliefs about what we should do and our actions. Research on motivation has been employed in various fields. In the field of business, a central question concerns work motivation, for example, what measures an employer can use to ensure that his employees are motivated. Motivation is also of particular interest to educational psychologists because of its crucial role in student learning. Specific interest has been given to the effects of intrinsic and extrinsic motivation in this field.Maslow's hierarchy of needs Content theory of human motivation includes both Abraham Maslow's hierarchy of needs and Herzberg's two-factor theory. Maslow's thesis is based on the idea that we are driven by our basic human needs. Maslow's theory is one of the most widely discussed theories of motivation. Furthermore, if some of our most basic requirements are not addressed, we may be unable to advance and meet our other needs. Abraham Maslow believed that man is inherently good and argued that individuals possess a constantly growing inner drive that has great potential. The needs hierarchy system is a commonly used scheme for classifying human motives. Maslow's hierarchy of needs emphasizes certain characteristics like family and community that involve the needs to be met. The basic needs, safety, love and belonging, and esteem have to be met first in order for the individual to actually reach self-actualization. The needs can overlap within the pyramid, but the lower needs have to be met first in order to move up. Some basic needs can include food and shelter. The need of safety has to do with receiving protection. For the individual to feel love and belonging, they have to feel some type of attachment by giving and receiving love. Having competence and control in personal life has to do with meeting the need of esteem. Not being able to meet the lower and higher needs can have a detrimental effect on mental health. This could lead to symptoms of depression, and lower self-esteem during adolescent years. If safety needs are not met during adolescence, then the individual will have less confidence. A study found that just having support from the community, friends can lead to decreased emotional challenges. It is important to satisfy these needs in order to reduce emotional and mental challenges over time.Maslow (1954) developed the hierarchy of needs consisting of five hierarchic classes. According to Maslow, people are motivated by unsatisfied needs. The needs, listed from basic (lowest-earliest) to most complex (highest-latest), are as follows: Physiology (hunger, thirst, sleep, etc.) Safety/Security/Shelter/Health Social/Love/Friendship Self-esteem/Recognition/Achievement Self-actualization/achievement of full potentialThe basic requirements build upon the first step in the pyramid: physiology. If there are deficits on this level, all behavior will be oriented to satisfy this deficit. Essentially, if someone has not slept or eaten adequately, they would not be interested in their self-esteem desires. Subsequently, people that have the second level, awakens a need for security and so on and so forth. After securing those two levels, the motives shift to the social sphere, the third level. Psychological requirements comprise the fourth level, while the top of the hierarchy consists of self-realization and self-actualization. Maslow's hierarchy of needs theory can be summarized as follows:Unconscious The conscious–unconscious distinction plays an important role in Sigmund Freud's psychoanalytical theories. According to him, the unconscious contains various repressed parts of the mind, like anxiety-inducing thoughts and socially unacceptable ideas. He identifies censorship as a force that keeps the repressed parts from entering consciousness. But unconscious instinctual impulses can nonetheless have a great influence on behavior in the form of unconscious motivation. When these instincts serve as a motive, the person is only aware of the goal of the motive, and not its actual source. Freud divides these instincts into sexual instincts, death instincts, and ego or self-preservation instincts. Sexual instincts are those that motivate humans to stay alive and ensure the continuation of mankind. On the other hand, Freud also maintains that humans have an inherent drive for self-destruction: the death instinct. Similar to the devil and angel that everyone has on their shoulder, the sexual instinct and death instinct are constantly battling each other to both be satisfied. The death instinct can be closely related to Freud's other concept, the id, which is our need to experience pleasure immediately, regardless of the consequences. The last type of instinct that contributes to motivation is the ego or self-preservation instinct. This instinct is geared towards assuring that a person feels validated in whatever behavior or thought they have. The mental censor, or door between the unconscious and preconscious, helps satisfy this instinct. For example, one may be sexually attracted to a person, due to their sexual instinct, but the self-preservation instinct prevents them to act on this urge until that person finds that it is socially acceptable to do so. Quite similarly to his psychic theory that deals with the id, ego, and superego, Freud's theory of instincts highlights the interdependence of these three instincts. All three serve as checks and balances system to control what instincts are acted on and what behaviors are used to satisfy as many of them at once. Priming is another source of unconscious motivation. It is a phenomenon whereby exposure to one stimulus influences a response to a subsequent stimulus, without conscious guidance or intention. For example, when someone is exposed to the word "cancer", they are afterward less likely to smoke a cigarette offered to them. There are various forms of priming, but visual and semantic priming are the most relevant for motivation. Because of this link to external stimuli, priming is closely related to exposure theory, which states that people tend to like things that they have been exposed to before. This is used by advertising companies to get people to buy their products. In product placements in movies and TV shows, for example, we see a product in our favorite movie, which makes us more inclined to buy that product when we see it again. Another example comes from former drug users, who are more tempted to relapse when exposed to stimuli associated with the drug.

Motivation is the reason for which humans and other animals initiate, continue, or terminate a behavior at a given time. Motivational states are commonly understood as forces acting within the agent that create a disposition to engage in goal-directed behavior. It is often held that different mental states compete with each other and that only the strongest state determines behavior. This means that we can be motivated to do something without actually doing it. The paradigmatic mental state providing motivation is desire. But various other states, such as beliefs about what one ought to do or intentions, may also provide motivation. Motivation is derived from the word 'motive', which denotes a person's needs, desires, wants, or urges. It is the process of motivating individuals to take action in order to achieve a goal. The psychological elements fueling people's behavior in the context of job goals might include a desire for money. Various competing theories have been proposed concerning the content of motivational states. They are known as content theories and aim to describe what goals usually or always motivate people. Abraham Maslow's hierarchy of needs and the ERG theory, for example, posit that humans have certain needs, which are responsible for motivation. Some of these needs, like for food and water, are more basic than other needs, such as for respect from others. On this view, the higher needs can only provide motivation once the lower needs have been fulfilled. Behaviorist theories try to explain behavior solely in terms of the relation between the situation and external, observable behavior without explicit reference to conscious mental states. Motivation may be either intrinsic, if the activity is desired because it is inherently interesting or enjoyable, or extrinsic, if the agent's goal is an external reward distinct from the activity itself. It has been argued that intrinsic motivation has more beneficial outcomes than extrinsic motivation. Motivational states can also be categorized according to whether the agent is fully aware of why he acts the way he does or not, referred to as conscious and unconscious motivation. Motivation is closely related to practical rationality. A central idea in this field is that we should be motivated to perform an action if we believe that we should perform it. Failing to fulfill this requirement results in cases of irrationality, known as akrasia or weakness of the will, in which there is a discrepancy between our beliefs about what we should do and our actions. Research on motivation has been employed in various fields. In the field of business, a central question concerns work motivation, for example, what measures an employer can use to ensure that his employees are motivated. Motivation is also of particular interest to educational psychologists because of its crucial role in student learning. Specific interest has been given to the effects of intrinsic and extrinsic motivation in this field.

10/GUI 10/GUI is a proposed new user interface paradigm. Created in 2009 by R. Clayton Miller, it combines multi-touch input with a new windowing manager. It splits the touch surface away from the screen, so that user fatigue is reduced and the users' hands don't obstruct the display. Instead of placing windows all over the screen, the windowing manager, Con10uum, uses a linear paradigm, with multi-touch used to navigate between and arrange the windows. An area at the right side of the touch screen brings up a global context menu, and a similar strip at the left side brings up application-specific menus. An open source community preview of the Con10uum window manager was made available in November, 2009.

In computing, multi-touch is technology that enables a surface (a touchpad or touchscreen) to recognize the presence of more than one point of contact with the surface at the same time. The origins of multitouch began at CERN, MIT, University of Toronto, Carnegie Mellon University and Bell Labs in the 1970s. CERN started using multi-touch screens as early as 1976 for the controls of the Super Proton Synchrotron. Capacitive multi-touch displays were popularized by Apple's iPhone in 2007. Plural-point awareness may be used to implement additional functionality, such as pinch to zoom or to activate certain subroutines attached to predefined gestures. Several uses of the term multi-touch resulted from the quick developments in this field, and many companies using the term to market older technology which is called gesture-enhanced single-touch or several other terms by other companies and researchers. Several other similar or related terms attempt to differentiate between whether a device can exactly determine or only approximate the location of different points of contact to further differentiate between the various technological capabilities, but they are often used as synonyms in marketing. Multi-touch is commonly implemented using capacitive sensing technology in mobile devices and smart devices. A capacitive touchscreen typically consists of a capacitive touch sensor, application-specific integrated circuit (ASIC) controller and digital signal processor (DSP) fabricated from CMOS (complementary metal–oxide–semiconductor) technology. A more recent alternative approach is optical touch technology, based on image sensor technology.Definition In computing, multi-touch is technology which enables a touchpad or touchscreen to recognize more than one or more than two points of contact with the surface. Apple popularized the term "multi-touch" in 2007 with which it implemented additional functionality, such as pinch to zoom or to activate certain subroutines attached to predefined gestures. The two different uses of the term resulted from the quick developments in this field, and many companies using the term to market older technology which is called gesture-enhanced single-touch or several other terms by other companies and researchers. Several other similar or related terms attempt to differentiate between whether a device can exactly determine or only approximate the location of different points of contact to further differentiate between the various technological capabilities, but they are often used as synonyms in marketing.Multi-touch gestures Multi-touch touchscreen gestures enable predefined motions to interact with the device and software. An increasing number of devices like smartphones, tablet computers, laptops or desktop computers have functions that are triggered by multi-touch gestures.10/GUI 10/GUI is a proposed new user interface paradigm. Created in 2009 by R. Clayton Miller, it combines multi-touch input with a new windowing manager. It splits the touch surface away from the screen, so that user fatigue is reduced and the users' hands don't obstruct the display. Instead of placing windows all over the screen, the windowing manager, Con10uum, uses a linear paradigm, with multi-touch used to navigate between and arrange the windows. An area at the right side of the touch screen brings up a global context menu, and a similar strip at the left side brings up application-specific menus. An open source community preview of the Con10uum window manager was made available in November, 2009.

Terminology The term "Zionism" is derived from the word Zion (Hebrew: ציון, Tzi-yon), a hill in Jerusalem, widely symbolizing the Land of Israel. Throughout eastern Europe in the late 19th century, numerous grassroots groups promoted the national resettlement of the Jews in their homeland, as well as the revitalization and cultivation of the Hebrew language. These groups were collectively called the "Lovers of Zion" and were seen as countering a growing Jewish movement toward assimilation. The first use of the term is attributed to the Austrian Nathan Birnbaum, founder of the Kadimah nationalist Jewish students' movement; he used the term in 1890 in his journal Selbstemanzipation! (Self-Emancipation), itself named almost identically to Leon Pinsker's 1882 book Auto-Emancipation.

Zionism (Hebrew: צִיּוֹנוּת Tsiyyonut [tsijoˈnut] after Zion) is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jewish tradition as the Land of Israel on the basis of a long Jewish connection and attachment to that land.Modern Zionism emerged in the late 19th century in Central and Eastern Europe as a national revival movement, both in reaction to newer waves of antisemitism and as a response to Haskalah, or Jewish Enlightenment. Soon after this, most leaders of the movement associated the main goal with creating the desired homeland in Palestine, then an area controlled by the Ottoman Empire. This process was seen by the Zionist Movement as a "ingathering of exiles" (kibbutz galuyot), an effort to put a stop to the exoduses and persecutions that have marked Jewish history by bringing the Jewish people back to their historic homeland.From 1897 to 1948, the primary goal of the Zionist Movement was to establish the basis for a Jewish homeland in Palestine, and thereafter to consolidate it. In a unique variation of the principle of self-determination, The Lovers of Zion united in 1884 and in 1897 the first Zionist congress was organized. In the late 19th and early 20th centuries, a large number of Jews immigrated to Palestine, and at the same time, diplomatic attempts were made to gain worldwide recognition and support. Since the establishment of the State of Israel in 1948, Zionism has continued primarily to advocate on behalf of Israel and to address threats to its continued existence and security.Zionism has never been a uniform movement. Its leaders, parties, and ideologies frequently diverged from one another. Compromises and concessions were made in order to achieve a shared cultural and political objective as a result of the growing antisemitism and yearning to return to the ancestral country. A variety of Zionism, called cultural Zionism, founded and represented most prominently by Ahad Ha'am, fostered a secular vision of a Jewish "spiritual center" in Israel. Unlike Theodor Herzl, the founder of political Zionism, Ahad Ha'am strived for Israel to be "a Jewish State, and not merely a State of Jews". Others have theorized it as the realization of a socialist utopia (Moses Hess), as a need for survival in the face of social prejudices by the affirmation of self-determination (Leon Pinsker), as the fulfilment of individual rights and freedoms (Max Nordau) or as the foundation of a Hebrew humanism (Martin Buber). Religious Zionism focuses on the religious aspects of Jewish identity and sees the effort to establish a state for Jews in the Land of Israel as an obligation arising from the Torah.Advocates of Zionism view it as a national liberation movement for the repatriation of a persecuted people to its ancestral homeland. Critics of Zionism view it as a colonialist, racist or exceptionalist ideology or movement.After almost two millennia of the Jewish diaspora residing in various countries without a national state, the Zionist movement was founded in the late 19th century by secular Jews, largely as a response by Ashkenazi Jews to rising antisemitism in Europe, exemplified by the Dreyfus affair in France and the anti-Jewish pogroms in the Russian Empire. The political movement was formally established by the Austro-Hungarian journalist Theodor Herzl in 1897 following the publication of his book Der Judenstaat (The Jewish State). At that time, the movement sought to encourage Jewish migration to Ottoman Palestine particularly among those Jewish communities who were poor, unassimilated and whose 'floating' presence caused disquiet, in Herzl's view, among assimilated Jews and stirred anti-Semitism among Christians.Although initially one of several Jewish political movements offering alternative responses to Jewish assimilation and antisemitism, Zionism expanded rapidly. In its early stages, supporters considered setting up a Jewish state in the historic territory of Palestine. After World War II and the destruction of Jewish life in Central and Eastern Europe where these alternative movements were rooted, it became dominant in the thinking about a Jewish national state. Creating an alliance with Great Britain and securing support for some years for Jewish emigration to Palestine, Zionists also recruited European Jews to immigrate there, especially Jews who lived in areas of the Russian Empire where anti-semitism was raging. The alliance with Britain was strained as the latter realized the implications of the Jewish movement for Arabs in Palestine, but the Zionists persisted. The movement was eventually successful in establishing Israel on May 14, 1948 (5 Iyyar 5708 in the Hebrew calendar), as the homeland for the Jewish people. The proportion of the world's Jews living in Israel has steadily grown since the movement emerged. By the early 21st century, more than 40% of the world's Jews lived in Israel, more than in any other country. These two outcomes represent the historical success of Zionism and are unmatched by any other Jewish political movement in the past 2,000 years. In some academic studies, Zionism has been analyzed both within the larger context of diaspora politics and as an example of modern national liberation movements.Zionism also sought the assimilation of Jews into the modern world. As a result of the diaspora, many of the Jewish people remained outsiders within their adopted countries and became detached from modern ideas. So-called "assimilationist" Jews desired complete integration into European society. They were willing to downplay their Jewish identity and in some cases to abandon traditional views and opinions in an attempt at modernization and assimilation into the modern world. A less extreme form of assimilation was called cultural synthesis. Those in favor of cultural synthesis desired continuity and only moderate evolution, and were concerned that Jews should not lose their identity as a people. "Cultural synthesists" emphasized both a need to maintain traditional Jewish values and faith and a need to conform to a modernist society, for instance, in complying with work days and rules.In 1975, the United Nations General Assembly passed Resolution 3379, which designated Zionism as "a form of racism and racial discrimination". The resolution was repealed in 1991 by replacing Resolution 3379 with Resolution 46/86.

Zionism (Hebrew: צִיּוֹנוּת Tsiyyonut [tsijoˈnut] after Zion) is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jewish tradition as the Land of Israel on the basis of a long Jewish connection and attachment to that land.Modern Zionism emerged in the late 19th century in Central and Eastern Europe as a national revival movement, both in reaction to newer waves of antisemitism and as a response to Haskalah, or Jewish Enlightenment. Soon after this, most leaders of the movement associated the main goal with creating the desired homeland in Palestine, then an area controlled by the Ottoman Empire. This process was seen by the Zionist Movement as a "ingathering of exiles" (kibbutz galuyot), an effort to put a stop to the exoduses and persecutions that have marked Jewish history by bringing the Jewish people back to their historic homeland.From 1897 to 1948, the primary goal of the Zionist Movement was to establish the basis for a Jewish homeland in Palestine, and thereafter to consolidate it. In a unique variation of the principle of self-determination, The Lovers of Zion united in 1884 and in 1897 the first Zionist congress was organized. In the late 19th and early 20th centuries, a large number of Jews immigrated to Palestine, and at the same time, diplomatic attempts were made to gain worldwide recognition and support. Since the establishment of the State of Israel in 1948, Zionism has continued primarily to advocate on behalf of Israel and to address threats to its continued existence and security.Zionism has never been a uniform movement. Its leaders, parties, and ideologies frequently diverged from one another. Compromises and concessions were made in order to achieve a shared cultural and political objective as a result of the growing antisemitism and yearning to return to the ancestral country. A variety of Zionism, called cultural Zionism, founded and represented most prominently by Ahad Ha'am, fostered a secular vision of a Jewish "spiritual center" in Israel. Unlike Theodor Herzl, the founder of political Zionism, Ahad Ha'am strived for Israel to be "a Jewish State, and not merely a State of Jews". Others have theorized it as the realization of a socialist utopia (Moses Hess), as a need for survival in the face of social prejudices by the affirmation of self-determination (Leon Pinsker), as the fulfilment of individual rights and freedoms (Max Nordau) or as the foundation of a Hebrew humanism (Martin Buber). Religious Zionism focuses on the religious aspects of Jewish identity and sees the effort to establish a state for Jews in the Land of Israel as an obligation arising from the Torah.Advocates of Zionism view it as a national liberation movement for the repatriation of a persecuted people to its ancestral homeland. Critics of Zionism view it as a colonialist, racist or exceptionalist ideology or movement.

Overview The common denominator among all Zionists has been a claim to Palestine, a land traditionally known in Jewish writings as the Land of Israel ("Eretz Israel") as a national homeland of the Jews and as the legitimate focus for Jewish national self-determination. It is based on historical ties and religious traditions linking the Jewish people to the Land of Israel. Zionism does not have a uniform ideology, but has evolved in a dialogue among a plethora of ideologies: General Zionism, Religious Zionism, Labor Zionism, Revisionist Zionism, Green Zionism, etc.

Overview The common denominator among all Zionists has been a claim to Palestine, a land traditionally known in Jewish writings as the Land of Israel ("Eretz Israel") as a national homeland of the Jews and as the legitimate focus for Jewish national self-determination. It is based on historical ties and religious traditions linking the Jewish people to the Land of Israel. Zionism does not have a uniform ideology, but has evolved in a dialogue among a plethora of ideologies: General Zionism, Religious Zionism, Labor Zionism, Revisionist Zionism, Green Zionism, etc.After almost two millennia of the Jewish diaspora residing in various countries without a national state, the Zionist movement was founded in the late 19th century by secular Jews, largely as a response by Ashkenazi Jews to rising antisemitism in Europe, exemplified by the Dreyfus affair in France and the anti-Jewish pogroms in the Russian Empire. The political movement was formally established by the Austro-Hungarian journalist Theodor Herzl in 1897 following the publication of his book Der Judenstaat (The Jewish State). At that time, the movement sought to encourage Jewish migration to Ottoman Palestine particularly among those Jewish communities who were poor, unassimilated and whose 'floating' presence caused disquiet, in Herzl's view, among assimilated Jews and stirred anti-Semitism among Christians.

Zionism (Hebrew: צִיּוֹנוּת Tsiyyonut [tsijoˈnut] after Zion) is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jewish tradition as the Land of Israel on the basis of a long Jewish connection and attachment to that land.Modern Zionism emerged in the late 19th century in Central and Eastern Europe as a national revival movement, both in reaction to newer waves of antisemitism and as a response to Haskalah, or Jewish Enlightenment. Soon after this, most leaders of the movement associated the main goal with creating the desired homeland in Palestine, then an area controlled by the Ottoman Empire. This process was seen by the Zionist Movement as a "ingathering of exiles" (kibbutz galuyot), an effort to put a stop to the exoduses and persecutions that have marked Jewish history by bringing the Jewish people back to their historic homeland.From 1897 to 1948, the primary goal of the Zionist Movement was to establish the basis for a Jewish homeland in Palestine, and thereafter to consolidate it. In a unique variation of the principle of self-determination, The Lovers of Zion united in 1884 and in 1897 the first Zionist congress was organized. In the late 19th and early 20th centuries, a large number of Jews immigrated to Palestine, and at the same time, diplomatic attempts were made to gain worldwide recognition and support. Since the establishment of the State of Israel in 1948, Zionism has continued primarily to advocate on behalf of Israel and to address threats to its continued existence and security.Zionism has never been a uniform movement. Its leaders, parties, and ideologies frequently diverged from one another. Compromises and concessions were made in order to achieve a shared cultural and political objective as a result of the growing antisemitism and yearning to return to the ancestral country. A variety of Zionism, called cultural Zionism, founded and represented most prominently by Ahad Ha'am, fostered a secular vision of a Jewish "spiritual center" in Israel. Unlike Theodor Herzl, the founder of political Zionism, Ahad Ha'am strived for Israel to be "a Jewish State, and not merely a State of Jews". Others have theorized it as the realization of a socialist utopia (Moses Hess), as a need for survival in the face of social prejudices by the affirmation of self-determination (Leon Pinsker), as the fulfilment of individual rights and freedoms (Max Nordau) or as the foundation of a Hebrew humanism (Martin Buber). Religious Zionism focuses on the religious aspects of Jewish identity and sees the effort to establish a state for Jews in the Land of Israel as an obligation arising from the Torah.Advocates of Zionism view it as a national liberation movement for the repatriation of a persecuted people to its ancestral homeland. Critics of Zionism view it as a colonialist, racist or exceptionalist ideology or movement.

After almost two millennia of the Jewish diaspora residing in various countries without a national state, the Zionist movement was founded in the late 19th century by secular Jews, largely as a response by Ashkenazi Jews to rising antisemitism in Europe, exemplified by the Dreyfus affair in France and the anti-Jewish pogroms in the Russian Empire. The political movement was formally established by the Austro-Hungarian journalist Theodor Herzl in 1897 following the publication of his book Der Judenstaat (The Jewish State). At that time, the movement sought to encourage Jewish migration to Ottoman Palestine particularly among those Jewish communities who were poor, unassimilated and whose 'floating' presence caused disquiet, in Herzl's view, among assimilated Jews and stirred anti-Semitism among Christians.Although initially one of several Jewish political movements offering alternative responses to Jewish assimilation and antisemitism, Zionism expanded rapidly. In its early stages, supporters considered setting up a Jewish state in the historic territory of Palestine. After World War II and the destruction of Jewish life in Central and Eastern Europe where these alternative movements were rooted, it became dominant in the thinking about a Jewish national state. Creating an alliance with Great Britain and securing support for some years for Jewish emigration to Palestine, Zionists also recruited European Jews to immigrate there, especially Jews who lived in areas of the Russian Empire where anti-semitism was raging. The alliance with Britain was strained as the latter realized the implications of the Jewish movement for Arabs in Palestine, but the Zionists persisted. The movement was eventually successful in establishing Israel on May 14, 1948 (5 Iyyar 5708 in the Hebrew calendar), as the homeland for the Jewish people. The proportion of the world's Jews living in Israel has steadily grown since the movement emerged. By the early 21st century, more than 40% of the world's Jews lived in Israel, more than in any other country. These two outcomes represent the historical success of Zionism and are unmatched by any other Jewish political movement in the past 2,000 years. In some academic studies, Zionism has been analyzed both within the larger context of diaspora politics and as an example of modern national liberation movements.Zionism also sought the assimilation of Jews into the modern world. As a result of the diaspora, many of the Jewish people remained outsiders within their adopted countries and became detached from modern ideas. So-called "assimilationist" Jews desired complete integration into European society. They were willing to downplay their Jewish identity and in some cases to abandon traditional views and opinions in an attempt at modernization and assimilation into the modern world. A less extreme form of assimilation was called cultural synthesis. Those in favor of cultural synthesis desired continuity and only moderate evolution, and were concerned that Jews should not lose their identity as a people. "Cultural synthesists" emphasized both a need to maintain traditional Jewish values and faith and a need to conform to a modernist society, for instance, in complying with work days and rules.In 1975, the United Nations General Assembly passed Resolution 3379, which designated Zionism as "a form of racism and racial discrimination". The resolution was repealed in 1991 by replacing Resolution 3379 with Resolution 46/86.

Overview The common denominator among all Zionists has been a claim to Palestine, a land traditionally known in Jewish writings as the Land of Israel ("Eretz Israel") as a national homeland of the Jews and as the legitimate focus for Jewish national self-determination. It is based on historical ties and religious traditions linking the Jewish people to the Land of Israel. Zionism does not have a uniform ideology, but has evolved in a dialogue among a plethora of ideologies: General Zionism, Religious Zionism, Labor Zionism, Revisionist Zionism, Green Zionism, etc.Green Zionism Green Zionism is a branch of Zionism primarily concerned with the environment of Israel. The only specifically environmentalist Zionist party is the Green Zionist Alliance.

Overview The common denominator among all Zionists has been a claim to Palestine, a land traditionally known in Jewish writings as the Land of Israel ("Eretz Israel") as a national homeland of the Jews and as the legitimate focus for Jewish national self-determination. It is based on historical ties and religious traditions linking the Jewish people to the Land of Israel. Zionism does not have a uniform ideology, but has evolved in a dialogue among a plethora of ideologies: General Zionism, Religious Zionism, Labor Zionism, Revisionist Zionism, Green Zionism, etc.

Overview The common denominator among all Zionists has been a claim to Palestine, a land traditionally known in Jewish writings as the Land of Israel ("Eretz Israel") as a national homeland of the Jews and as the legitimate focus for Jewish national self-determination. It is based on historical ties and religious traditions linking the Jewish people to the Land of Israel. Zionism does not have a uniform ideology, but has evolved in a dialogue among a plethora of ideologies: General Zionism, Religious Zionism, Labor Zionism, Revisionist Zionism, Green Zionism, etc.Liberal Zionism General Zionism (or Liberal Zionism) was initially the dominant trend within the Zionist movement from the First Zionist Congress in 1897 until after the First World War. General Zionists identified with the liberal European middle class to which many Zionist leaders such as Herzl and Chaim Weizmann aspired. Liberal Zionism, although not associated with any single party in modern Israel, remains a strong trend in Israeli politics advocating free market principles, democracy and adherence to human rights. Their political arm was one of the ancestors of the modern-day Likud. Kadima, the main centrist party during the 2000s that split from Likud and is now defunct, however, did identify with many of the fundamental policies of Liberal Zionist ideology, advocating among other things the need for Palestinian statehood in order to form a more democratic society in Israel, affirming the free market, and calling for equal rights for Arab citizens of Israel. In 2013, Ari Shavit suggested that the success of the then-new Yesh Atid party (representing secular, middle-class interests) embodied the success of "the new General Zionists."Dror Zeigerman writes that the traditional positions of the General Zionists—"liberal positions based on social justice, on law and order, on pluralism in matters of State and Religion, and on moderation and flexibility in the domain of foreign policy and security"—are still favored by important circles and currents within certain active political parties.Philosopher Carlo Strenger describes a modern-day version of Liberal Zionism (supporting his vision of "Knowledge-Nation Israel"), rooted in the original ideology of Herzl and Ahad Ha'am, that stands in contrast to both the romantic nationalism of the right and the Netzah Yisrael of the ultra-Orthodox. It is marked by a concern for democratic values and human rights, freedom to criticize government policies without accusations of disloyalty, and rejection of excessive religious influence in public life. "Liberal Zionism celebrates the most authentic traits of the Jewish tradition: the willingness for incisive debate; the contrarian spirit of davka; the refusal to bow to authoritarianism." Liberal Zionists see that "Jewish history shows that Jews need and are entitled to a nation-state of their own. But they also think that this state must be a liberal democracy, which means that there must be strict equality before the law independent of religion, ethnicity or gender."

Zionism (Hebrew: צִיּוֹנוּת Tsiyyonut [tsijoˈnut] after Zion) is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jewish tradition as the Land of Israel on the basis of a long Jewish connection and attachment to that land.Modern Zionism emerged in the late 19th century in Central and Eastern Europe as a national revival movement, both in reaction to newer waves of antisemitism and as a response to Haskalah, or Jewish Enlightenment. Soon after this, most leaders of the movement associated the main goal with creating the desired homeland in Palestine, then an area controlled by the Ottoman Empire. This process was seen by the Zionist Movement as a "ingathering of exiles" (kibbutz galuyot), an effort to put a stop to the exoduses and persecutions that have marked Jewish history by bringing the Jewish people back to their historic homeland.From 1897 to 1948, the primary goal of the Zionist Movement was to establish the basis for a Jewish homeland in Palestine, and thereafter to consolidate it. In a unique variation of the principle of self-determination, The Lovers of Zion united in 1884 and in 1897 the first Zionist congress was organized. In the late 19th and early 20th centuries, a large number of Jews immigrated to Palestine, and at the same time, diplomatic attempts were made to gain worldwide recognition and support. Since the establishment of the State of Israel in 1948, Zionism has continued primarily to advocate on behalf of Israel and to address threats to its continued existence and security.Zionism has never been a uniform movement. Its leaders, parties, and ideologies frequently diverged from one another. Compromises and concessions were made in order to achieve a shared cultural and political objective as a result of the growing antisemitism and yearning to return to the ancestral country. A variety of Zionism, called cultural Zionism, founded and represented most prominently by Ahad Ha'am, fostered a secular vision of a Jewish "spiritual center" in Israel. Unlike Theodor Herzl, the founder of political Zionism, Ahad Ha'am strived for Israel to be "a Jewish State, and not merely a State of Jews". Others have theorized it as the realization of a socialist utopia (Moses Hess), as a need for survival in the face of social prejudices by the affirmation of self-determination (Leon Pinsker), as the fulfilment of individual rights and freedoms (Max Nordau) or as the foundation of a Hebrew humanism (Martin Buber). Religious Zionism focuses on the religious aspects of Jewish identity and sees the effort to establish a state for Jews in the Land of Israel as an obligation arising from the Torah.Advocates of Zionism view it as a national liberation movement for the repatriation of a persecuted people to its ancestral homeland. Critics of Zionism view it as a colonialist, racist or exceptionalist ideology or movement.

Zionism (Hebrew: צִיּוֹנוּת Tsiyyonut [tsijoˈnut] after Zion) is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jewish tradition as the Land of Israel on the basis of a long Jewish connection and attachment to that land.Modern Zionism emerged in the late 19th century in Central and Eastern Europe as a national revival movement, both in reaction to newer waves of antisemitism and as a response to Haskalah, or Jewish Enlightenment. Soon after this, most leaders of the movement associated the main goal with creating the desired homeland in Palestine, then an area controlled by the Ottoman Empire. This process was seen by the Zionist Movement as a "ingathering of exiles" (kibbutz galuyot), an effort to put a stop to the exoduses and persecutions that have marked Jewish history by bringing the Jewish people back to their historic homeland.From 1897 to 1948, the primary goal of the Zionist Movement was to establish the basis for a Jewish homeland in Palestine, and thereafter to consolidate it. In a unique variation of the principle of self-determination, The Lovers of Zion united in 1884 and in 1897 the first Zionist congress was organized. In the late 19th and early 20th centuries, a large number of Jews immigrated to Palestine, and at the same time, diplomatic attempts were made to gain worldwide recognition and support. Since the establishment of the State of Israel in 1948, Zionism has continued primarily to advocate on behalf of Israel and to address threats to its continued existence and security.Zionism has never been a uniform movement. Its leaders, parties, and ideologies frequently diverged from one another. Compromises and concessions were made in order to achieve a shared cultural and political objective as a result of the growing antisemitism and yearning to return to the ancestral country. A variety of Zionism, called cultural Zionism, founded and represented most prominently by Ahad Ha'am, fostered a secular vision of a Jewish "spiritual center" in Israel. Unlike Theodor Herzl, the founder of political Zionism, Ahad Ha'am strived for Israel to be "a Jewish State, and not merely a State of Jews". Others have theorized it as the realization of a socialist utopia (Moses Hess), as a need for survival in the face of social prejudices by the affirmation of self-determination (Leon Pinsker), as the fulfilment of individual rights and freedoms (Max Nordau) or as the foundation of a Hebrew humanism (Martin Buber). Religious Zionism focuses on the religious aspects of Jewish identity and sees the effort to establish a state for Jews in the Land of Israel as an obligation arising from the Torah.Advocates of Zionism view it as a national liberation movement for the repatriation of a persecuted people to its ancestral homeland. Critics of Zionism view it as a colonialist, racist or exceptionalist ideology or movement.Overview The common denominator among all Zionists has been a claim to Palestine, a land traditionally known in Jewish writings as the Land of Israel ("Eretz Israel") as a national homeland of the Jews and as the legitimate focus for Jewish national self-determination. It is based on historical ties and religious traditions linking the Jewish people to the Land of Israel. Zionism does not have a uniform ideology, but has evolved in a dialogue among a plethora of ideologies: General Zionism, Religious Zionism, Labor Zionism, Revisionist Zionism, Green Zionism, etc.Negation of the life in the Diaspora Negation of life in the Diaspora is a central assumption in Zionism. Some supporters of Zionism believed that Jews in the Diaspora were prevented from their full growth in Jewish individual and national life.The rejection of life in the diaspora was not limited to secular Zionism; many religious Zionists shared this opinion, but not all religious Zionism did. Rav Cook, considered one of the most important religious Zionist thinkers, characterized the diaspora as a flawed and alienated existence marked by decline, narrowness, displacement, solitude, and frailty. He believed that the diasporan way of life is diametrically opposed to a "national renaissance," which manifests itself not only in the return to Zion but also in the return to nature and creativity, revival of heroic and aesthetic values, and the resurgence of individual and societal power.Jewish religious belief holds that the Land of Israel is a God-given inheritance of the Children of Israel based on the Torah, particularly the books of Genesis and Exodus, as well as on the later Prophets. According to the Book of Genesis, Canaan was first promised to Abraham's descendants; the text is explicit that this is a covenant between God and Abraham for his descendants. The belief that God had assigned Canaan to the Israelites as a Promised Land is also conserved also in Christian and Islamic traditions.Among Jews in the Diaspora, the Land of Israel was revered in a cultural, national, ethnic, historical, and religious sense. They thought of a return to it in a future messianic age. Return to Zion remained a recurring theme among generations, particularly in Passover and Yom Kippur prayers, which traditionally concluded with "Next year in Jerusalem", and in the thrice-daily Amidah (Standing prayer). The biblical prophecy of Kibbutz Galuyot, the ingathering of exiles in the Land of Israel as foretold by the Prophets, became a central idea in Zionism.Religious Zionism Religious Zionism is an ideology that combines Zionism and observant Judaism. Before the establishment of the State of Israel, Religious Zionists were mainly observant Jews who supported Zionist efforts to build a Jewish state in the Land of Israel. One of the core ideas in Religious Zionism is the belief that the ingathering of exiles in the Land of Israel and the establishment of Israel is Atchalta De'Geulah ("the beginning of the redemption"), the initial stage of the geula.After the Six-Day War and the capture of the West Bank, a territory referred to in Jewish terms as Judea and Samaria, right-wing components of the Religious Zionist movement integrated nationalist revindication and evolved into what is sometimes known as Neo-Zionism. Their ideology revolves around three pillars: the Land of Israel, the People of Israel and the Torah of Israel.

Zionism (Hebrew: צִיּוֹנוּת Tsiyyonut [tsijoˈnut] after Zion) is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jewish tradition as the Land of Israel on the basis of a long Jewish connection and attachment to that land.Modern Zionism emerged in the late 19th century in Central and Eastern Europe as a national revival movement, both in reaction to newer waves of antisemitism and as a response to Haskalah, or Jewish Enlightenment. Soon after this, most leaders of the movement associated the main goal with creating the desired homeland in Palestine, then an area controlled by the Ottoman Empire. This process was seen by the Zionist Movement as a "ingathering of exiles" (kibbutz galuyot), an effort to put a stop to the exoduses and persecutions that have marked Jewish history by bringing the Jewish people back to their historic homeland.From 1897 to 1948, the primary goal of the Zionist Movement was to establish the basis for a Jewish homeland in Palestine, and thereafter to consolidate it. In a unique variation of the principle of self-determination, The Lovers of Zion united in 1884 and in 1897 the first Zionist congress was organized. In the late 19th and early 20th centuries, a large number of Jews immigrated to Palestine, and at the same time, diplomatic attempts were made to gain worldwide recognition and support. Since the establishment of the State of Israel in 1948, Zionism has continued primarily to advocate on behalf of Israel and to address threats to its continued existence and security.Zionism has never been a uniform movement. Its leaders, parties, and ideologies frequently diverged from one another. Compromises and concessions were made in order to achieve a shared cultural and political objective as a result of the growing antisemitism and yearning to return to the ancestral country. A variety of Zionism, called cultural Zionism, founded and represented most prominently by Ahad Ha'am, fostered a secular vision of a Jewish "spiritual center" in Israel. Unlike Theodor Herzl, the founder of political Zionism, Ahad Ha'am strived for Israel to be "a Jewish State, and not merely a State of Jews". Others have theorized it as the realization of a socialist utopia (Moses Hess), as a need for survival in the face of social prejudices by the affirmation of self-determination (Leon Pinsker), as the fulfilment of individual rights and freedoms (Max Nordau) or as the foundation of a Hebrew humanism (Martin Buber). Religious Zionism focuses on the religious aspects of Jewish identity and sees the effort to establish a state for Jews in the Land of Israel as an obligation arising from the Torah.Advocates of Zionism view it as a national liberation movement for the repatriation of a persecuted people to its ancestral homeland. Critics of Zionism view it as a colonialist, racist or exceptionalist ideology or movement.Terminology The term "Zionism" is derived from the word Zion (Hebrew: ציון, Tzi-yon), a hill in Jerusalem, widely symbolizing the Land of Israel. Throughout eastern Europe in the late 19th century, numerous grassroots groups promoted the national resettlement of the Jews in their homeland, as well as the revitalization and cultivation of the Hebrew language. These groups were collectively called the "Lovers of Zion" and were seen as countering a growing Jewish movement toward assimilation. The first use of the term is attributed to the Austrian Nathan Birnbaum, founder of the Kadimah nationalist Jewish students' movement; he used the term in 1890 in his journal Selbstemanzipation! (Self-Emancipation), itself named almost identically to Leon Pinsker's 1882 book Auto-Emancipation.

Description Bores occur in relatively few locations worldwide, usually in areas with a large tidal range (typically more than 6 meters (20 ft) between high and low tide) and where incoming tides are funneled into a shallow, narrowing river or lake via a broad bay. The funnel-like shape not only increases the tidal range, but it can also decrease the duration of the flood tide, down to a point where the flood appears as a sudden increase in the water level. A tidal bore takes place during the flood tide and never during the ebb tide.

Description Bores occur in relatively few locations worldwide, usually in areas with a large tidal range (typically more than 6 meters (20 ft) between high and low tide) and where incoming tides are funneled into a shallow, narrowing river or lake via a broad bay. The funnel-like shape not only increases the tidal range, but it can also decrease the duration of the flood tide, down to a point where the flood appears as a sudden increase in the water level. A tidal bore takes place during the flood tide and never during the ebb tide.

Description Bores occur in relatively few locations worldwide, usually in areas with a large tidal range (typically more than 6 meters (20 ft) between high and low tide) and where incoming tides are funneled into a shallow, narrowing river or lake via a broad bay. The funnel-like shape not only increases the tidal range, but it can also decrease the duration of the flood tide, down to a point where the flood appears as a sudden increase in the water level. A tidal bore takes place during the flood tide and never during the ebb tide.

A tidal bore, often simply given as bore in context, is a tidal phenomenon in which the leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay, reversing the direction of the river or bay's current. It is a strong tide that pushes up the river, against the current.

Terminal velocity in the presence of buoyancy force When the buoyancy effects are taken into account, an object falling through a fluid under its own weight can reach a terminal velocity (settling velocity) if the net force acting on the object becomes zero. When the terminal velocity is reached the weight of the object is exactly balanced by the upward buoyancy force and drag force. That isW {\displaystyle W} is the weight of the object,

ρ {\displaystyle \rho } is the density of the fluid through which the object is falling, andA {\displaystyle A} is the projected area of the object.In reality, an object approaches its terminal speed asymptotically. Buoyancy effects, due to the upward force on the object by the surrounding fluid, can be taken into account using Archimedes' principle: the mass m {\displaystyle m} has to be reduced by the displaced fluid mass ρ V {\displaystyle \rho V} , with V {\displaystyle V} the volume of the object. So instead of m {\displaystyle m} use the reduced mass m r = m − ρ V {\displaystyle m_{r}=m-\rho V} in this and subsequent formulas. The terminal speed of an object changes due to the properties of the fluid, the mass of the object and its projected cross-sectional surface area. Air density increases with decreasing altitude, at about 1% per 80 metres (260 ft) (see barometric formula). For objects falling through the atmosphere, for every 160 metres (520 ft) of fall, the terminal speed decreases 1%. After reaching the local terminal velocity, while continuing the fall, speed decreases to change with the local terminal speed.ρ {\displaystyle \rho } is the density of the fluid,ρ s {\displaystyle \rho _{s}} is the density of the object,V {\displaystyle V} is the characteristic velocity (taken as terminal velocity, V t {\displaystyle V_{t}} ).Substitution of equations (2–4) in equation (1) and solving for terminal velocity, V t {\displaystyle V_{t}} to yield the following expression

Terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid (air is the most common example). It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object. Since the net force on the object is zero, the object has zero acceleration.In fluid dynamics an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving.As the speed of an object increases, so does the drag force acting on it, which also depends on the substance it is passing through (for example air or water). At some speed, the drag or force of resistance will equal the gravitational pull on the object (buoyancy is considered below). At this point the object stops accelerating and continues falling at a constant speed called the terminal velocity (also called settling velocity). An object moving downward faster than the terminal velocity (for example because it was thrown downwards, it fell from a thinner part of the atmosphere, or it changed shape) will slow down until it reaches the terminal velocity. Drag depends on the projected area, here represented by the object's cross-section or silhouette in a horizontal plane. An object with a large projected area relative to its mass, such as a parachute, has a lower terminal velocity than one with a small projected area relative to its mass, such as a dart. In general, for the same shape and material, the terminal velocity of an object increases with size. This is because the downward force (weight) is proportional to the cube of the linear dimension, but the air resistance is approximately proportional to the cross-section area which increases only as the square of the linear dimension. For very small objects such as dust and mist, the terminal velocity is easily overcome by convection currents which can prevent them from reaching the ground at all, and hence they can stay suspended in the air for indefinite periods. Air pollution and fog are examples of convection currents.

Terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid (air is the most common example). It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object. Since the net force on the object is zero, the object has zero acceleration.In fluid dynamics an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving.As the speed of an object increases, so does the drag force acting on it, which also depends on the substance it is passing through (for example air or water). At some speed, the drag or force of resistance will equal the gravitational pull on the object (buoyancy is considered below). At this point the object stops accelerating and continues falling at a constant speed called the terminal velocity (also called settling velocity). An object moving downward faster than the terminal velocity (for example because it was thrown downwards, it fell from a thinner part of the atmosphere, or it changed shape) will slow down until it reaches the terminal velocity. Drag depends on the projected area, here represented by the object's cross-section or silhouette in a horizontal plane. An object with a large projected area relative to its mass, such as a parachute, has a lower terminal velocity than one with a small projected area relative to its mass, such as a dart. In general, for the same shape and material, the terminal velocity of an object increases with size. This is because the downward force (weight) is proportional to the cube of the linear dimension, but the air resistance is approximately proportional to the cross-section area which increases only as the square of the linear dimension. For very small objects such as dust and mist, the terminal velocity is easily overcome by convection currents which can prevent them from reaching the ground at all, and hence they can stay suspended in the air for indefinite periods. Air pollution and fog are examples of convection currents.

Nazi Germany Walter Laqueur traces the Jewish-Bolshevik conspiracy theory to Nazi ideologue Alfred Rosenberg, for whom Bolshevism was "the revolt of the Jewish, Slavic and Mongolian races against the German (Aryan) element in Russia". Germans, according to Rosenberg, had been responsible for Russia's historic achievements and had been sidelined by the Bolsheviks, who did not represent the interests of the Russian people, but instead those of its ethnic Jewish and Chinese population.Michael Kellogg, in his Ph.D. thesis, argues that the racist ideology of Nazis was to a significant extent influenced by White émigrés in Germany, many of whom, while being former subjects of the Russian Empire, were of non-Russian descent: ethnic Germans, residents of Baltic lands including Baltic Germans, and Ukrainians. Of particular role was their Aufbau organization (Aufbau: Wirtschafts-politische Vereinigung für den Osten (Reconstruction: Economic-Political Organization for the East)). For example, its leader was instrumental in making The Protocols of The Elders of Zion available in German language. He argues that early Hitler was rather philosemitic, and became rabidly antisemitic after 1919 under the influence of the White émigré convictions about the conspiracy of the Jews, an unseen unity from financial capitalists to Bolsheviks, to conquer the world. Therefore, his conclusion is that White émigrés were at the source of the Nazi concept of Jewish Bolshevism. Annemarie Sammartino argues that this view is contestable. While there is no doubt that White emigres were instrumental in reinforcing the idea of 'Jewish Bolshevism' among Nazis, the concept is also found in many German early post–World War I documents. Also, Germany had its own share of Jewish Communists "to provide fodder for the paranoid fantasies of German antisemites" without Russian Bolsheviks.During the 1920s, Hitler declared that the mission of the Nazi movement was to destroy "Jewish Bolshevism". Hitler asserted that the "three vices" of "Jewish Marxism" were democracy, pacifism and internationalism, and that the Jews were behind Bolshevism, communism and Marxism. In private conversations held in 1940s, Hitler labelled Christianity as a Jewish product analogous to Judeo-Bolshevism: