There was also something called a "curse tablet" which Romans used to curse people they did not like. They would often let them drift to the river so that the curse will be carried to where that person who has the curse. But many curses are made when people are jealous and they want that person who has the curse to not do well.
The opposite of a curse is a blessing.
Ventricular fibrillation
Ventricular fibrillation (often shortened to VF or V-Fib) is a type of "arrhythmia" of the heart. "Arrhythmia" means the heart is not beating normally.
When a person is in ventricular fibrillation, the heart does not beat in any kind of pattern. Instead, it quivers and twitches very quickly.
This problem is called "ventricular" fibrillation because it affects the ventricles of the heart. The ventricles are the biggest parts of the heart. Their job is to pump blood (which carries oxygen) to the lungs and the rest of the body. When a person is in ventricular fibrillation, the ventricles cannot do this job. This means that the lungs, brain, and other organs will not get enough blood or oxygen.
Ventricular fibrillation is a medical emergency. Without enough blood and oxygen, no part of the body can survive. If ventricular fibrillation continues for long enough, the blood will stop circulating around the body. The person's breathing and heart will stop. The person will die unless they get treatment quickly.
Ventricular fibrillation can be stopped by shocking the person with electricity from a defibrillator. If a defibrillator is not available, CPR (cardiopulmonary resuscitation) should be done to keep the blood flowing until an ambulance comes or a defibrillator is available.
Doctors or paramedics can also give special medicines called anti-arrhythmic medicines, which can make the heart start beating normally again. Some common anti-arrhythmic medicines are amiodarone and lidocaine.
If a person with ventricular fibrillation is treated right away, treatment is 90% successful (it works in 9 out of 10 people). But treatment gets 10% less successful after every minute (so if treatment starts after one minute, it will work in only 8 out of 10 people. After 5 minutes, it will work in only 4 out of 10 people.) So getting treatment as soon as possible is very important. If a person cannot be treated with medicine or a defibrillator right away, CPR will help keep blood and oxygen flowing through the person's body until treatment arrives.
In patients who are very likely to keep having ventricular fibrillation, a special defibrillator can be put into their chest by a surgeon. (This special defibrillator is called an "implantable cardioverter-defibrillator.") Any time the person goes into ventricular fibrillation, the defibrillator will give the person's heart an electric shock, to bring the heart back into a normal rhythm.
Seal
Seal or SEAL may refer to articles connected to a variety of meanings:
Some of these names referred originally to the marine mammal.
Tachycardia
Tachycardia is the fast beating of the heart. In adults, it refers to heart rates higher than 100 beats per minute. Tachycardia may be a normal physiological response to stress, but depending on the cause and how healthy the patient is, tachycardia could be harmful and need medical treatment. In some cases, tachycardia can cause death.
Tachycardia can be harmful in two ways. First, when the heart beats too rapidly, it may perform inefficiently. Second, the faster the heart beats, the more oxygen and nutrients the heart requires. This can be especially problematic for patients suffering from ischaemic heart disease.
Material fracture
A fracture is the separation of a body into more than one piece under the action of stress.
The word "fracture" is often applied to bones of living creatures or to crystals or crystalline materials, such as gemstones or metal. Sometimes, fractures can happen without the object actually separating into two or more pieces.
Shear stress
Shear stress is a stress state where the stress is parallel to the surface of the material, as opposed to normal stress when the stress is to the surface.
Shear stress is relevant to themotion of fluids upon surfaces, which result in the generation of shear stress.
Also constructions in soil can fail due to shear; e.g., the weight of an earth-filled dam may cause the subsoil to collapse, like a small landslide.
Tension
Tension may mean:
Tension (mechanics)
Tension is a reaction force applied by a stretched string (rope or a similar object) on the objects which stretch it. The direction of the force of tension is parallel to the string, towards the string.
Tension exists also inside the string itself: if the string is made up of two parts, tension is the force which the two parts of the string apply on each other. The amount of tension in the string determines whether it will break, as well as its vibrational properties, which are used in musical instruments.
Shear
Shear as a noun could mean:
Shear as a verb or shearing could mean:
Flow
Flow may mean:
I.O.U.
I.O.U. means "I Owe You" or "I Owe Unto". It is a note between two people that is used to say that one person owes something to the other. It is usually used for money. I.O.U.'s are most often only used between people that know each other very well, for example, friends.
Deformation
In engineering mechanics, deformation is a change in shape that is result of a force that influences the object.
It can be a result of tensile (pulling) forces, compressive (pushing) forces, shear, bending or torsion (twisting).
Depending on the type of material, size and shape of the object, and the forces used, various types of deformation may result.
This type of deformation is reversible. Once the forces are no longer applied, the object returns to its original shape. As the name implies, elastic (rubber) has a rather large elastic deformation range. The thermoplastics and metals have moderate elastic deformation ranges while ceramics, crystals, and hard thermosetting polymers undergo almost no elastic deformation. Malleable materials do not undergo elastic deformation.
A phenomenon only discovered in modern times is metal fatigue, which occurs primarily in ductile metals. It was originally thought that a material deformed only within the elastic range returned completely to its original state once the forces were removed. However, faults are introduced at the molecular level with each deformation. After many deformations, cracks will begin to appear, followed soon after by a fracture, with no apparent plastic deformation in between. Depending on the material, shape, and how close to the elastic limit it is deformed, failure may require thousands, millions, billions, or trillions of deformations.
Metal fatigue has been a major cause of aircraft failure, especially before the process was well understood.
This type of deformation is not reversible. But an object in the plastic deformation range will first have undergone elastic deformation, which is reversible, so the object will return part way to its original shape. Soft thermoplastics have a rather large plastic deformation range as do ductile metals such as copper, silver, and gold. Steel does, too, but not iron. Hard thermosetting plastics, rubber, crystals, and ceramics have minimal plastic deformation ranges. Perhaps the material with the largest plastic deformation range is wet chewing gum, which can be stretched dozens of times its original length.
This type of deformation is also not reversible. A break occurs after the material has reached the end of the elastic, and then plastic, deformation ranges. At this point forces accumulate until they are sufficient to cause a fracture. All materials will eventually fracture, if sufficient forces are applied.