title: Hypoxia (medical)

text: Because hemoglobin is a darker red when it is not bound to oxygen (deoxyhemoglobin), as opposed to the rich red color that it has when bound to oxygen (oxyhemoglobin), when seen through the skin it has an increased tendency to reflect blue light back to the eye. In cases where the oxygen is displaced by another molecule, such as carbon monoxide, the skin may appear 'cherry red' instead of cyanotic. Hypoxia can cause premature birth, and injure the liver, among other deleterious effects.


title: Hypoxia (medical)

text: Hypoxia that is localized to a region of the body, such as an organ or a limb. is usually the consequence of ischemia, the reduced perfusion to that organ or limb, and may not necessarily be associated with general hypoxemia. A locally reduced perfusion is generally caused by an increased resistance to flow through the blood vessels of the affected area.


title: Hypoxia (medical)

text: Ischemia is a restriction in blood supply to any tissue, muscle group, or organ, causing a shortage of oxygen. Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue i.e. hypoxia and microvascular dysfunction. It also means local hypoxia in a given part of a body sometimes resulting from vascular occlusion such as vasoconstriction, thrombosis, or embolism. Ischemia comprises not only insufficiency of oxygen, but also reduced availability of nutrients and inadequate removal of metabolic wastes. Ischemia can be a partial (poor perfusion) or total blockage.


title: Hypoxia (medical)

text: Compartment syndrome is a condition in which increased pressure within one of the body's anatomical compartments results in insufficient blood supply to tissue within that space. There are two main types: acute and chronic. Compartments of the leg or arm are most commonly involved.


title: Hypoxia (medical)

text: If tissue is not being perfused properly, it may feel cold and appear pale; if severe, hypoxia can result in cyanosis, a blue discoloration of the skin. If hypoxia is very severe, a tissue may eventually become gangrenous.


title: Hypoxia (medical)

text: Any living tissue can be affected by hypoxia, but some are particularly sensitive, or have more noticeable or notable consequences.


title: Hypoxia (medical)

text: Cerebral hypoxia is hypoxia specifically involving the brain. The four categories of cerebral hypoxia in order of increasing severity are: diffuse cerebral hypoxia (DCH), focal cerebral ischemia, cerebral infarction, and global cerebral ischemia. Prolonged hypoxia induces neuronal cell death via apoptosis, resulting in a hypoxic brain injury.


title: Hypoxia (medical)

text: Oxygen deprivation can be hypoxic (reduced general oxygen availability) or ischemic (oxygen deprivation due to a disruption in blood flow) in origin. Brain injury as a result of oxygen deprivation is generally termed hypoxic injury. Hypoxic ischemic encephalopathy (HIE) is a condition that occurs when the entire brain is deprived of an adequate oxygen supply, but the deprivation is not total. While HIE is associated in most cases with oxygen deprivation in the neonate due to birth asphyxia, it can occur in all age groups, and is often a complication of cardiac arrest.


title: Hypoxia (medical)

text: Long term use of some types of contact lenses can result in hypoxia damage to the corneas. The corneas are not perfused and get their oxygen from the atmosphere by diffusion. Impermeable contact lenses form a barrier to this diffusion and this can cause damage to the corneas.


title: Hypoxia (medical)

text: Intrauterine hypoxia, also known as fetal hypoxia, occurs when the fetus is deprived of an adequate supply of oxygen. It may be due to a variety of reasons such as prolapse or occlusion of the umbilical cord, placental infarction, maternal diabetes (prepregnancy or gestational diabetes) and maternal smoking. Intrauterine growth restriction may cause or be the result of hypoxia. Intrauterine hypoxia can cause cellular damage that occurs within the central nervous system (the brain and spinal cord). This results in an increased mortality rate, including an increased risk of sudden infant death syndrome (SIDS). Oxygen deprivation in the fetus and neonate have been implicated as either a primary or as a contributing risk factor in numerous neurological and neuropsychiatric disorders such as epilepsy, attention deficit hyperactivity disorder, eating disorders and cerebral palsy.


title: Hypoxia (medical)

text: Tumor hypoxia is the situation where tumor cells have been deprived of oxygen. As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in healthy tissues. Hypoxic microenvironements in solid tumors are a result of available oxygen being consumed within 70 to 150 μm of tumour vasculature by rapidly proliferating tumor cells thus limiting the amount of oxygen available to diffuse further into the tumor tissue. In order to support continuous growth and proliferation in challenging hypoxic environments, cancer cells are found to alter their metabolism. Furthermore, hypoxia is known to change cell behavior and is associated with extracellular matrix remodeling and increased migratory and metastatic behavior. Tumour hypoxia is usually associated with highly malignant tumours, which frequently do not respond well to treatment.


title: Hypoxia (medical)

text: In acute exposure to hypoxic hypoxia on the vestibular system and the visuo-vestibular interactions, the gain of the vestibulo–ocular reflex (VOR) decreases under mild hypoxia at altitude. Postural control is also disturbed by hypoxia at altitude, postural sway is increased, and there is a correlation between hypoxic stress and adaptive tracking performance.


title: Hypoxia (medical)

text: Arterial oxygen tension can be measured by blood gas analysis of an arterial blood sample, and less reliably by pulse oximetry, which is not a complete measure of circulatory oxygen sufficiency. If there is insufficient blood flow or insufficient hemoglobin in the blood (anemia), tissues can be hypoxic even when there is high arterial oxygen saturation.


title: Hypoxia (medical)

text: Oxygen passively diffuses in the lung alveoli according to a concentration gradient, also referred to as a partial pressure gradient. Inhaled air rapidly reaches saturation with water vapour, which slightly reduces the partial pressures of the other components. Oxygen diffuses from the inhaleded air, to arterial blood, where its partial pressure is around 100 mmHg (13.3 kPa). In the blood, oxygen is bound to hemoglobin, a protein in red blood cells. The binding capacity of hemoglobin is influenced by the partial pressure of oxygen in the environment, as described by the oxygen–hemoglobin dissociation curve. A smaller amount of oxygen is transported in solution in the blood.


title: Hypoxia (medical)

text: In systemic tissues, oxygen again diffuses down a concentration gradient into cells and their mitochondria, where it is used to produce energy in conjunction with the breakdown of glucose, fats, and some amino acids. Hypoxia can result from a failure at any stage in the delivery of oxygen to cells. This can include low partial pressures of oxygen in the breathing gas, problems with diffusion of oxygen in the lungs through the interface between air and blood, insufficient available hemoglobin, problems with blood flow to the end user tissue, problems with the breathing cycle regarding rate and volume, and physiological and mechanical dead space


title: Hypoxia (medical)

text: Experimentally, oxygen diffusion becomes rate limiting when arterial oxygen partial pressure falls to 60 mmHg (5.3 kPa) or below.


title: Hypoxia (medical)

text: Almost all the oxygen in the blood is bound to hemoglobin, so interfering with this carrier molecule limits oxygen delivery to the perfused tissues. Hemoglobin increases the oxygen-carrying capacity of blood by about 40-fold, with the ability of hemoglobin to carry oxygen influenced by the partial pressure of oxygen in the local environment, a relationship described in the oxygen–hemoglobin dissociation curve. When the ability of hemoglobin to carry oxygen is degraded, a hypoxic state can result.


title: Hypoxia (medical)

text: Ischemia, meaning insufficient blood flow to a tissue, can also result in hypoxia in the affected tissues. This is called 'ischemic hypoxia'. Ischemia can be caused by an embolism, a heart attack that decreases overall blood flow, trauma to a tissue that results in damage reducing perfusion, and a variety of other causes. A consequence of insufficient blood flow causing local hypoxia is gangrene that occurs in diabetes.


title: Hypoxia (medical)

text: Diseases such as peripheral vascular disease can also result in local hypoxia. Symptoms are worse when a limb is used, increasing the oxygen demand in the active muscles. Pain may also be felt as a result of increased hydrogen ions leading to a decrease in blood pH (acidosis) created as a result of anaerobic metabolism.


title: Hypoxia (medical)

text: G-LOC, or g-force induced loss of consciousness, is a special case of ischemic hypoxia which occurs when the body is subjected to high enough acceleration sustained for long enough to lower cerebral blood pressure and circulation to the point where loss of consciousness occurs due to cerebral hypoxia. The human body is most sensitive to longitudinal acceleration towards the head, as this causes the largest hydrostatic pressure deficit in the head.


title: Hypoxia (medical)

text: This refers specifically to hypoxic states where the arterial content of oxygen is insufficient. This can be caused by alterations in respiratory drive, such as in respiratory alkalosis, physiological or pathological shunting of blood, diseases interfering in lung function resulting in a ventilation-perfusion mismatch, such as a pulmonary embolus, or alterations in the partial pressure of oxygen in the environment or lung alveoli, such as may occur at altitude or when diving.


title: Hypoxia (medical)

text: Common disorders that can cause respiratory disfunction include trauma to the head and spinal cord, nontraumatic acute myelopathies, demyelinating disorders, stroke, Guillain–Barré syndrome, and myasthenia gravis. These dysfunctions may necessitate mechanical ventilation. Some chronic neuromuscular disorders such as motor neuron disease and muscular dystrophy may require ventilatory support in advanced stages.


title: Hypoxia (medical)

text: Carbon monoxide competes with oxygen for binding sites on hemoglobin molecules. As carbon monoxide binds with hemoglobin hundreds of times tighter than oxygen, it can prevent the carriage of oxygen.


title: Hypoxia (medical)

text: Carbon monoxide poisoning can occur acutely, as with smoke intoxication, or over a period of time, as with cigarette smoking. Due to physiological processes, carbon monoxide is maintained at a resting level of 4–6 ppm. This is increased in urban areas (7–13 ppm) and in smokers (20–40 ppm). A carbon monoxide level of 40 ppm is equivalent to a reduction in hemoglobin levels of 10 g/L.


title: Hypoxia (medical)

text: Carbon monoxie has a second toxic effect, namely removing the allosteric shift of the oxygen dissociation curve and shifting the foot of the curve to the left. In so doing, the hemoglobin is less likely to release its oxygen at the peripheral tissues. Certain abnormal hemoglobin variants also have higher than normal affinity for oxygen, and so are also poor at delivering oxygen to the periphery.


title: Hypoxia (medical)

text: Atmospheric pressure reduces with altitude and proportionally, so does the oxygen content of the air. The reduction in the partial pressure of inspired oxygen at higher altitudes lowers the oxygen saturation of the blood, ultimately leading to hypoxia. The clinical features of altitude sickness include: sleep problems, dizziness, headache and oedema.


title: Hypoxia (medical)

text: The breathing gas may contain an insufficient partial pressure of oxygen. Such situations may lead to unconsciousness without symptoms since carbon dioxide levels remain normal and the human body senses pure hypoxia poorly. Hypoxic breathing gases can be defined as mixtures with a lower oxygen fraction than air, though gases containing sufficient oxygen to reliably maintain consciousness at normal sea level atmospheric pressure may be described as normoxic even when the oxygen fraction is slightly below normoxic. Hypoxic breathing gas mixtures in this context are those which will not reliably maintain consciousness at sea level pressure.


title: Hypoxia (medical)

text: One of the most widespread circumstances of exposure to hypoxic breathing gas is ascent to altitudes where the ambient pressure drops sufficiently to reduce the partial pressure of oxygen to hypoxic levels.


title: Hypoxia (medical)

text: Gases with as little as 2% oxygen by volume in a helium diluent are used for deep diving operations. The ambient pressure at 190 msw is sufficient to provide a partial pressure of about 0.4 bar, which is suitable for saturation diving. As the divers are decompressed, the breathing gas must be oxygenated to maintain a breathable atmosphere/.


title: Hypoxia (medical)

text: It is also possible for the breathing gas for diving to have a dynamically controlled oxygen partial pressure, known as a set point, which is maintained in the breathing gas circuit of a diving rebreather by addition of oxygen and diluent gas to maintain the desired oxygen partial pressure at a safe level between hypoxic and hyperoxic at the ambient pressure due to the current depth. A malfunction of the control system may lead to the gas mixture becoming hypoxic at the current depth.


title: Hypoxia (medical)

text: A special case of hypoxic breathing gas is encountered in deep freediving where the partial pressure of the oxygen in the lung gas is depleted during the dive, but remains sufficient at depth, and when it drops during ascent, it becomes too hypoxic to maintain consciousness, and the diver loses consciousness before reaching the surface.


title: Hypoxia (medical)

text: Hypoxic gases may also occur in industrial, mining, and firefighting environments. Some of these may also be toxic or narcotic, others are just asphyxiant. Some are recognisable by smell, others are odourless.


title: Hypoxia (medical)

text: Inert gas asphyxiation may be deliberate with use of a suicide bag. Accidental death has occurred in cases where concentrations of nitrogen in controlled atmospheres, or methane in mines, has not been detected or appreciated.


title: Hypoxia (medical)

text: Hemoglobin's function can also be lost by chemically oxidizing its iron atom to its ferric form. This form of inactive hemoglobin is called methemoglobin and can be made by ingesting sodium nitrite as well as certain drugs and other chemicals.


title: Hypoxia (medical)

text: Hemoglobin plays a substantial role in carrying oxygen throughout the body, and when it is deficient, anemia can result, causing 'anaemic hypoxia' if tissue oxygenation is decreased. Iron deficiency is the most common cause of anemia. As iron is used in the synthesis of hemoglobin, less hemoglobin will be synthesised when there is less iron, due to insufficient intake, or poor absorption.


title: Hypoxia (medical)

text: Anemia is typically a chronic process that is compensated over time by increased levels of red blood cells via upregulated erythropoetin. A chronic hypoxic state can result from a poorly compensated anaemia.


title: Hypoxia (medical)

text: Histotoxic hypoxia (also called histoxic hypoxia) is the inability of cells to take up or use oxygen from the bloodstream, despite physiologically normal delivery of oxygen to such cells and tissues. Histotoxic hypoxia results from tissue poisoning, such as that caused by cyanide (which acts by inhibiting cytochrome oxidase) and certain other poisons like hydrogen sulfide (byproduct of sewage and used in leather tanning).


title: Hypoxia (medical)

text: Tissue hypoxia from low oxygen delivery may be due to low haemoglobin concentration (anaemic hypoxia), low cardiac output (stagnant hypoxia) or low haemoglobin saturation (hypoxic hypoxia). The consequence of oxygen deprivation in tissues is a switch to anaerobic metabolism at the cellular level. As such, reduced systemic blood flow may result in increased serum lactate. Serum lactate levels have been correlated with illness severity and mortality in critically ill adults and in ventilated neonates with respiratory distress.


title: Hypoxia (medical)

text: All vertebrates must maintain oxygen homeostasis to survive, and have evolved physiological systems to ensure adequate oygenation of all tissues. In air breathing vertebrates this is based on lungs to acquire the oxygen, hemoglobin in red corpuscles to transport it, a vasculature to distribute, and a heart to deliver. Short term variations in the levels of oxygenation are sensed by chemoreceptor cells which respond by activating existing proteins, and over longer terms by regulation of gene transcription. Hypoxia is also involved in the pathogenesis of some common and severe pathologies.


title: Hypoxia (medical)

text: The most common causes of death in an aging population include myocardial infarction, stroke and cancer. These diseases share a common feature that limitation of oxygen availability contributes to the development of the pathology. Cells and organisms are also able to respond adaptively to hypoxic conditions, in ways that help them to cope with these adverse conditions. Several systems can sense oxygen concentration and may respond with adaptations to acute and long-term hypoxia.


title: Hypoxia (medical)

text: The systems activated by hypoxia usually help cells to survive and overcome the hypoxic conditions. Erythropoietin, which is produced in larger quantities by the kidneys under hypoxic conditions, is an essential hormone that stimulates production of red blood cells, which are the primary transporter of blood oxygen, and glycolytic enzymes are involved in anaerobic ATP formation.


title: Hypoxia (medical)

text: Hypoxia-inducible factors (HIFs) are transcription factors that respond to decreases in available oxygen in the cellular environment, or hypoxia. The HIF signaling cascade mediates the effects of hypoxia on the cell. Hypoxia often keeps cells from differentiating. However, hypoxia promotes the formation of blood vessels, and is important for the formation of a vascular system in embryos and tumors. The hypoxia in wounds also promotes the migration of keratinocytes and the restoration of the epithelium. It is therefore not surprising that HIF-1 modulation was identified as a promising treatment paradigm in wound healing.


title: Hypoxia (medical)

text: Exposure of a tissue to repeated short periods of hypoxia, between periods of normal oxygen levels, influences the tissue's later response to a prolonged ischaemic exposuret. Thus is known as ischaemic preconditioning, and it is known to occur in many tissues.


title: Hypoxia (medical)

text: If oxygen delivery to cells is insufficient for the demand (hypoxia), electrons will be shifted to pyruvic acid in the process of lactic acid fermentation. This temporary measure (anaerobic metabolism) allows small amounts of energy to be released. Lactic acid build up (in tissues and blood) is a sign of inadequate mitochondrial oxygenation, which may be due to hypoxemia, poor blood flow (e.g., shock) or a combination of both. If severe or prolonged it could lead to cell death.


title: Hypoxia (medical)

text: In humans, hypoxia is detected by the peripheral chemoreceptors in the carotid body and aortic body, with the carotid body chemoreceptors being the major mediators of reflex responses to hypoxia. This response does not control ventilation rate at normal P, but below normal the activity of neurons innervating these receptors increases dramatically, so much as to override the signals from central chemoreceptors in the hypothalamus, increasing P despite a falling P


title: Hypoxia (medical)

text: In most tissues of the body, the response to hypoxia is vasodilation. By widening the blood vessels, the tissue allows greater perfusion.


title: Hypoxia (medical)

text: By contrast, in the lungs, the response to hypoxia is vasoconstriction. This is known as hypoxic pulmonary vasoconstriction, or "HPV", and has the effect of redirecting blood away from poorly ventilated regions, which helps match perfusion to ventilation, giving a more even oxygenation of blood from different parts of the lungs. In conditions of hypoxic breathing gas, such as at high altitude, HPV is generalized over the entire lung, but with sustained exposure to generalized hypoxia, HPV is suppressed.


title: Hypoxia (medical)

text: Hypoxic ventilatory response (HVR) is the increase in ventilation induced by hypoxia that allows the body to take in and transport lower concentrations of oxygen at higher rates. It is initially elevated in lowlanders who travel to high altitude, but reduces significantly over time as people acclimatize.


title: Hypoxia (medical)

text: When the pulmonary capillary pressure remains elevated chronically (for at least 2 weeks), the lungs become even more resistant to pulmonary edema because the lymph vessels expand greatly, increasing their capability of carrying fluid away from the interstitial spaces perhaps as much as 10-fold. Therefore, in patients with chronic mitral stenosis, pulmonary capillary pressures of 40 to 45 mm Hg have been measured without the development of lethal pulmonary edema.


title: Hypoxia (medical)

text: There are several potential physiologic mechanisms for hypoxemia, but in patients with chronic obstructive pulmonary disease (COPD), ventilation/perfusion (V/Q) mismatching is most common, with or without alveolar hypoventilation, as indicated by arterial carbon dioxide concentration. Hypoxemia caused by V/Q mismatching in COPD is relatively easy to correct, and relatively small flow rates of supplemental oxygen (less than 3 L/min for the majority of patients) are required for long term oxygen therapy (LTOT). Hypoxemia normally stimulates ventilation and produces dyspnea, but these and the other signs and symptoms of hypoxia are sufficiently variable in COPD to limit their value in patient assessment. Chronic alveolar hypoxia is the main factor leading to development of cor pulmonale — right ventricular hypertrophy with or without overt right ventricular failure — in patients with COPD. Pulmonary hypertension adversely affects survival in COPD, proportional to resting mean pulmonary artery pressure elevation. Although the severity of airflow obstruction as measured by forced expiratory volume tests FEV1 correlates best with overall prognosis in COPD, chronic hypoxemia increases mortality and morbidity for any severity of disease. Large-scale studies of long term oxygen therapy in patients with COPD show a dose–response relationship between daily hours of supplemental oxygen use and survival. Continuous, 24-hours-per-day oxygen use in appropriately selected patients may produce a significant survival benefit.


title: Hypoxia (medical)

text: The brain has relatively high energy requirements, using about 20% of the oxygen under resting conditions, but low reserves, which make it specially vulnerable to hypoxia. In normal conditions, an increased demand for oxytgen is easily compensated by an increased cerebral blood flow. but under conditions when there is insufficient oxygen available, increased blood flow may not be sufficient to compensate, and hypoxia can result in brain injury. A longer duration of cerebral hypoxia will generally result in larger areas of the brain being affected. The brainstem, hippocampus and cerebral cortex seem to be the most vulnerable regions. Injury becomes irreversible if ogygenation is not soon restored. Most cell death is by necrosis but delayed apoptosis also occurs. In addition, presynaptic neurons release large amounts of glutamate which further increases Ca influx and causes catastrophic collapse in postsynaptic cells. Although it is the only way to save the tissue, reperfusion also produces reactive oxygen species and inflammatory cell infiltration, which induces further cell death. If the hypoxia is not too severe, cells can suppress some of their functions, such as protein synthesis and spontaneous electrical activity, in a process called "penumbra", which is reversible if the oxygen supply is resumed soon enough.


title: Hypoxia (medical)

text: Parts of the heart are exposed to ischemic hypoxia in the event of occlusion of a coronary artery. Short periods of ischaemia are reversible if reperfused within about 20 minutes, without development of necrosis, but the phenomenon known as "stunning" is generally evident. If hypoxia continues beyond this period, necrosis propagates through the myocardial tissue. Energy metabolism in the affected area shifts from mitochondrial respiration to anaerobic glycolysis almost immediately, with concurrent reduction of effectiveness of contractions, which soon cease. Anaerobic products accumulate in the muscle cells, which develop acidosis and osmotic load leading to cellular edema. Intracellular Ca2+ increases and eventually leads to cell necrosis. Arterial flow must be restored to return to aerobic metabolism and prevent necrosis of the affected muscle cells, but this also causes further damage by reperfusion injury. Myocadial stunning has been described as "prolonged postischaemic dysfunction of viable tissue salvaged by reperfusion", which manifests as temporary contractile failure in oxygenated muscle tissue. This may be caused by a release of reactive oxygen species during the early stages of reperfusion.


title: Hypoxia (medical)

text: As tumors grow, regions of relative hypoxia develop as the oxygen supply is unevenly utilized by the tumor cells. The formation of new blood vessels is necessary for continued tumor growth, and is also an important factor in metastasis, as the route by which cancerous cells are transported to other sites.


title: Hypoxia (medical)

text: Acute presentation may include dyspnea (shortness of breath) and tachypnea (rapid, often shallow, breathing). Severity of symptom presentation is commonly an indication of severity of hypoxia. Tachycardia (rapid pulse) may develop to compensate for low arterial oxygen tension. Stridor may be heard in upper airway obstruction, and cyanosis may indicate severe hypoxia. Neurological symptoms and organ function deterioration occur when the oxygen delivery is severely compromised. In moderate hypoxia, restlessness, headache and confusion may occur, with coma and eventual death possible in severe cases.


title: Hypoxia (medical)

text: In chronic presentation, dyspnea following exertion is most commonly mentioned. Symptoms of the underlying condition that caused the hypoxia may be apparent, and can help with differential diagnosis. A productive cough and fever may be present with lung infection, and leg edema may suggest heart failure.


title: Hypoxia (medical)

text: An arterial blood gas test (ABG) may be done, which usually includes measurements of oxygen content, hemoglobin, oxygen saturation (how much of the hemoglobin is carrying oxygen), arterial partial pressure of oxygen (P), partial pressure of carbon dioxide (P), blood pH level, and bicarbonate (HCO)


title: Hypoxia (medical)

text: X-rays or CT scans of the chest and airways can reveal abnormalities that may affect ventilation or perfusion.


title: Hypoxia (medical)

text: A ventilation/perfusion scan, also called a V/Q lung scan, is a type of medical imaging using scintigraphy and medical isotopes to evaluate the circulation of air and blood within a patient's lungs, in order to determine the ventilation/perfusion ratio. The ventilation part of the test looks at the ability of air to reach all parts of the lungs, while the perfusion part evaluates how well blood circulates within the lungs.


title: Hypoxia (medical)

text: Treatment will depend on severity and may also depend on the cause, as some cases are due to external causes and removing them and treating acute symptoms may be sufficient, but where the symptoms are due to underlying pathology, treatment of the obvious symptoms may only provide temporary or partial relief, so differential diagnosis can be important in selecting definitive treatment.


title: Hypoxia (medical)

text: Hypoxemic hypoxia: Low oxygen tension in the arterial blood (P) is generally an indication of inability of the lungs to properly oxygenate the blood. Internal causes include hypoventilation, impaired alveolar diffusion, and pulmonary shunting. External causes include hypoxic environment, which could be caused by low ambient pressure or unsuitable breathing gas. Both acute and chronic hypoxia and hypercapnia caused by respiratory dysfunction can produce neurological symptoms such as encephalopathy, seizures, headache, papilledema, and asterixis. Obstructive sleep apnea syndrome may cause morning headaches


title: Hypoxia (medical)

text: Circulatory Hypoxia: Caused by insufficient perfusion of the affected tissues by blood which is adequately oxygenated. This may be generalised, due to cardiac failure or hypovolemia, or localised, due to infarction or localised injury.


title: Hypoxia (medical)

text: Anemic Hypoxia is caused by a deficit in oxygen-carrying capacity, usually due to low hemoglobin levels, leading to generalised inadequate oxygen delivery.


title: Hypoxia (medical)

text: Histotoxic Hypoxia (Dysoxia) is a consequence of cells being unable to utilize oxygen effectively. A classic example is cyanide poisoning which inhibits the enzyme cytochrome C oxidase in the mitochondria, blocking the use of oxygen to make ATP.


title: Hypoxia (medical)

text: Critical illness polyneuropathy or myopathy should be considered in the intensive care unit when patients have difficulty coming off the ventilator.


title: Hypoxia (medical)

text: Prevention can be as simple as risk management of occupational exposure to hypoxic environments, and commonly involves the use of environmental monitoring and personal protective equipment. Prevention of hypoxia as a predictable consequence of medical conditions requires prevention of those conditions. Screening of demographics known to be at risk for specific disorders may be useful.


title: Hypoxia (medical)

text: To counter the effects of high-altitude diseases, the body must return arterial P toward normal. Acclimatization, the means by which the body adapts to higher altitudes, only partially restores P to standard levels. Hyperventilation, the body's most common response to high-altitude conditions, increases alveolar P by raising the depth and rate of breathing. However, while P does improve with hyperventilation, it does not return to normal. Studies of miners and astronomers working at 3000 meters and above show improved alveolar P with full acclimatization, yet the P level remains equal to or even below the threshold for continuous oxygen therapy for patients with chronic obstructive pulmonary disease (COPD). In addition, there are complications involved with acclimatization. Polycythemia, in which the body increases the number of red blood cells in circulation, thickens the blood, raising the risk of blood clots.


title: Hypoxia (medical)

text: In high-altitude situations, only oxygen enrichment or compartment pressurisation can counteract the effects of hypoxia. Pressurisation is practicable in vehicles, and for emergencies in ground installations. By increasing the concentration of oxygen in the at ambient pressure, the effects of lower barometric pressure are countered and the level of arterial P is restored toward normal capacity. A small amount of supplemental oxygen reduces the equivalent altitude in climate-controlled rooms. At 4000 m, raising the oxygen concentration level by 5% via an oxygen concentrator and an existing ventilation system provides an altitude equivalent of 3000 m, which is much more tolerable for the increasing number of low-landers who work in high altitude. In a study of astronomers working in Chile at 5050 m, oxygen concentrators increased the level of oxygen concentration by almost 30 percent (that is, from 21 percent to 27 percent). This resulted in increased worker productivity, less fatigue, and improved sleep.


title: Hypoxia (medical)

text: Oxygen concentrators are suited for high altitude oxygen enrichment of climate-controlled environments. They require little maintenance and electricity, utilise a locally available source of oxygen, and eliminate the expensive task of transporting oxygen cylinders to remote areas. Offices and housing often already have climate-controlled rooms, in which temperature and humidity are kept at a constant level.


title: Hypoxia (medical)

text: Treatment and management depend on circumstances. For most high altitude situations the risk is known, and prevention is appropriate. At low altitudes hypoxia is more likely to be associated with a medical problem or an unexpected contingency, and treatment is more likely to be provided to suit the specific case. It is necessary to identify persons who need oxygen therapy, as supplemental oxygen is required to treat most causes of hypoxia, but different oxygen concentrations may be appropriate.


title: Hypoxia (medical)

text: Treatment will depend on the cause of hypoxia. If it is determined that there is an external cause, and it can be removed, then treatment may be limited to support and returning the system to normal oxygenation. In other cases a longer course of treatment may be necessary, and this may require supplemental oxygen over a fairly long term or indefinitely.


title: Hypoxia (medical)

text: There are three main aspects of oxygenation treatment: maintaining patent airways, providing sufficient oxygen content of the inspired air, and improving the diffusion in the lungs. In some cases treatment may extend to improving oxygen capacity of the blood, which may include volumetric and circulatory intervention and support, hyperbaric oxygen therapy and treatment of intoxication.


title: Hypoxia (medical)

text: Invasive ventilation may be necessary or an elective option in surgery. This generally involves a positive pressure ventilator connected to an endotracheal tube, and allows precise delivery of ventilation, accurate monitoring of F, and positive end-expiratory pressure, and can be combined with anaesthetic gas delivery. In some cases a tracheotomy may be necessary. Decreasing metabolic rate by reducing body temperature lowers oxygen demand and consumption, and can minimise the effects of tissue hypoxia, especially in the brain, and therapeutic hypothermia based on this principle may be useful.


title: Hypoxia (medical)

text: Where the problem is due to respiratory failure. it is desirable to treat the underlying cause. In cases of pulmonary edema, diuretics can be used to reduce the oedems. Steroids may be effective in some cases of interstitial lung disease, and in extreme cases, extracorporeal membrane oxygenation (ECMO) can be used.


title: Hypoxia (medical)

text: Hyperbaric oxygen has been found useful for treating some forms of localized hypoxia, including poorly perfused trauma injuries such as Crush injury, compartment syndrome, and other acute traumatic ischemias. It is the definitive treatment for severe decompression sickness, which is largely a condition involving localized hypoxia initially caused by inert gas embolism and inflammatory reactions to extravascular bubble growth. It is also effective in Carbon monoxide poisoning. and diabetic foot.


title: Hypoxia (medical)

text: A prescription renewal for home oxygen following hospitalization requires an assessment of the patient for ongoing hypoxemia.


title: Hypoxia (medical)

text: Hypoxia leading to reduced capacity to respond appropriately, or to loss of consciosness, has been implicated in incidents where the direct cause of death was not hypoxia. This is recorded in underwater diving incidents, where drowning has often been given as cause of death, high altitude mountaineering, where exposure, hypothermia and falls have been consequences, flying in unpressurized aircraft, and aerobatic maneuvers, where loss of control leading to a crash is possible.


title: Hypoxia (medical)

text: Hypoxia is a common disorder but there are many possible causes. Prevalence is variable. Some of the causes are very common, like pneumonia or chronic obstructive pulmonary disease; some are quite rare like hypoxia due to cyanide poisoning. Others, like reduced oxygen tension at high altitude, may be regionally distributed or associated with a specific demographic.


title: Hypoxia (medical)

text: Generalized hypoxia is an occupational hazard in several high-risk occupations, including firefighting, professional diving, mining and underground rescue, and flying at high altitudes in unpressurised aircraft.


title: Hypoxia (medical)

text: Localized hypoxia may be a complication of diabetes, decompression sickness, and of trauma that affects blood supply to the extremities.


title: Hypoxia (medical)

text: Hypoxia due to underdeveloped lung function is a common complication of premature birth. In the United States, intrauterine hypoxia and birth asphyxia were listed together as the tenth leading cause of neonatal death.


title: Hypoxia (medical)

text: Silent hypoxia (also known as happy hypoxia) is generalised hypoxia that does not coincide with shortness of breath. This presentation is known to be a complication of COVID-19, and is also known in atypical pneumonia, altitude sickness, and rebreather malfunction accidents.


title: Hypoxia (medical)

text: The 2019 Nobel Prize in Physiology or Medicine was awarded to William G. Kaelin Jr., Sir Peter J. Ratcliffe, and Gregg L. Semenza in recognition of their discovery of cellular mechanisms to sense and adapt to different oxygen concentrations, establishing a basis for how oxygen levels affect physiological function.


title: Abdullah of Saudi Arabia

text: Abdullah bin Abdulaziz Al Saud ( "ʿAbd Allāh ibn ʿAbd al ʿAzīz Āl Saʿūd", Najdi Arabic pronunciation: ; 1 August 1924 – 23 January 2015) was King and Prime Minister of Saudi Arabia from 1 August 2005 until his death in 2015. Prior to his ascension, he was Crown Prince of Saudi Arabia since 13 June 1982. He was the tenth son of King Abdulaziz, the founder of Saudi Arabia, and the fifth of Abdulaziz's six sons who were kings.


title: Abdullah of Saudi Arabia

text: Abdullah was the son of King Abdulaziz and Fahda bint Asi Al Shuraim. His mother was a member of the Al Rashid dynasty, historical rivals of the Al Saud dynasty. Abdullah held important political posts throughout most of his adult life. In 1961 he became mayor of Mecca, his first public office. The following year, he was appointed commander of the Saudi Arabian National Guard, a post he was still holding when he became king. He also served as deputy defense minister and was named crown prince when his half-brother Fahd took the throne in 1982. After King Fahd suffered a serious stroke in 1995, Abdullah became the "de facto" ruler of Saudi Arabia until ascending the throne a decade later.


title: Abdullah of Saudi Arabia

text: During his reign, Abdullah maintained close relations with the United States and the United Kingdom and bought billions of dollars worth of defense equipment from both states. He also gave women the right to vote for municipal councils and to compete in the Olympics. Abdullah maintained the status quo when there were waves of protest in the kingdom during the Arab Spring. According to a 2013 BBC report, Saudi Arabia could obtain nuclear weapons at will from Pakistan during Abdullah's reign due to the close relations between the two countries. The King had a longstanding relationship with Pakistan, and brokered a compromise between General Pervez Musharraf and ousted Prime Minister Nawaz Sharif, whom he had requested to be exiled to Saudi Arabia for a 10-year exile, following his ouster in the 1999 Pakistani coup d'état.


title: Abdullah of Saudi Arabia

text: The three crown princes during Abdullah's reign were among the full brothers of King Fahd. Upon becoming king in 2005, Abdullah appointed his half-brother Sultan bin Abdulaziz as crown prince. When Sultan died in 2011, Sultan's full brother Nayef was named heir to the throne, but Nayef himself died the next year. Abdullah then named Salman bin Abdulaziz as crown prince. According to various reports, the King married up to 30 times and had more than 35 children. He was among the wealthiest royals in the world. Upon his death in 2015 at age 90, Abdullah was succeeded by his half-brother Salman.


title: Abdullah of Saudi Arabia

text: Abdullah is said to have been born on 1 August 1924 in Riyadh. However, some sources state that this date is incorrect, and that he was approximately eight years older. He was the tenth son of King Abdulaziz. His mother, Fahda bint Asi Al Shuraim, was a member of the Al Rashid dynasty, longtime rivals of the Al Saud dynasty. She was descended from the powerful Shammar tribe and was the daughter of former tribe chief Asi bin Shuraim. She died when Abdullah was six years old. Abdullah had two younger full-sisters, Nouf and Seeta, and two maternal half-brothers, Abdulaziz bin Saud and Mishaal bin Saud, who were the children of his mother's first marriage to Saud bin Abdulaziz Al Rashid. Madawi Al-Rasheed argues that Abdullah's maternal roots and his earlier experience of a speech impediment led to delay in his rise to higher status among the sons of King Abdulaziz.


title: Abdullah of Saudi Arabia

text: In August 1963, Abdullah was made commander of Saudi National Guard replacing Saad bin Saud, a son of King Saud, in the post. This post allowed him to secure his position in the House of Saud. SANG, which had been based on the Ikhwan, became a modern armed force under his command. Beginning 1985, SANG also sponsored the Janadiriyah festival that institutionalized traditional folk dances, camel races and tribal heritage.


title: Abdullah of Saudi Arabia

text: King Khalid appointed Abdullah as second deputy prime minister on 29 March 1975 just four days after his kingship which was a reflection of his status as second in the line of succession to the Saudi throne. Therefore, he became the number three in the Saudi administration. However, his appointment caused friction in the House of Saud. Then-Crown Prince Fahd, together with his full-brothers, known as the Sudairi Seven, supported the appointment of their own full brother, Sultan. Abdullah was pressured to cede control of SANG in return for his appointment as second deputy prime minister. In August 1977, this generated a debate among hundreds of princes in Riyadh. Abdullah did not relinquish authority of SANG in that he feared that this would weaken his authority.


title: Abdullah of Saudi Arabia

text: In March 1979 when Crown Prince Fahd left Saudi Arabia and stayed in Europe for a long time Prince Abdullah presided over the council of ministers and held a much more active role in diplomatic affairs of Saudi Arabia. During the same period he was one of the members of the inner family council which was led by King Khalid and included Abdullah's half-brothers Prince Mohammed, Crown Prince Fahd, Prince Sultan and Prince Abdul Muhsin as well as his uncles Prince Ahmed and Prince Musaid.


title: Abdullah of Saudi Arabia

text: On 13 June 1982 King Khalid died, and Fahd bin Abdulaziz became King. Abdullah became Crown Prince the same day who also maintained his position as head of the National Guard. During his years as crown prince, Abdullah bin Abdulaziz was described as a supporter of accommodation. He managed to group a large number of fringe and marginalized princes discontented with the prospect of the succession being passed among the Sudairi brothers one after the other. His control of the National Guard was also a key factor to his success in becoming crown prince. When King Fahd was incapacitated by a major stroke in 1995, Crown Prince Abdullah acted as "de facto" regent of Saudi Arabia.


title: Abdullah of Saudi Arabia

text: On 4 June 2000, the Al Saud Family Council was established by Crown Prince Abdullah to discuss some private issues, including the business activities of House of Saud members and the marriages of princesses to nonroyals. In May 2001 he did not accept an invitation to visit Washington due to the US support for Israel in the Second Intifada. He also appeared more eager than King Fahd to cut government spending and open Saudi Arabia up economically. He pushed for Saudi membership of the World Trade Organization, surprising some.


title: Abdullah of Saudi Arabia

text: In August 2001, he ordered then Saudi Ambassador to the US, Bandar bin Sultan, to return to Washington from Aspen to deliver a message. This reportedly occurred after Crown Prince Abdullah witnessed brutality inflicted by an Israeli soldier upon a Palestinian woman. “This is it. Those bastards!" Abdullah yelled over the phone, according to an account that Bandar has given associates. “Even women they're stepping all over them." Later, he also condemned Israel for attacking families of suspects.


title: Abdullah of Saudi Arabia

text: In 2002, he developed the Arab Peace Initiative, commonly referred to as the "Abdullah plan", to achieve a mutually agreed-on resolution of the Arab–Israeli conflict. The initiative was adopted at the Arab League's Beirut summit in March 2002.


title: Abdullah of Saudi Arabia

text: On the second anniversary of the September 11 attacks, Crown Prince Abdullah wrote a letter to US President George W. Bush, which ended with the following words:


title: Abdullah of Saudi Arabia

text: "God Almighty, in His wisdom, tests the faithful by allowing such calamities to happen. But He, in His mercy, also provides us with the will and determination, generated by faith, to enable us to transform such tragedies into great achievements, and crises that seem debilitating are transformed into opportunities for the advancement of humanity. I only hope that, with your cooperation and leadership, a new world will emerge out of the rubble of the World Trade Center: a world that is blessed by the virtues of freedom, peace, prosperity and harmony."


title: Abdullah of Saudi Arabia

text: By late 2003, after the Saudi Arabian branch of al-Qaeda carried out a series of bombings that threatened to destabilize the country, Crown Prince Abdullah, together with other decision-making elites began to deal with political concerns. As Toby Jones wrote in "Middle East Report": One of such moves was his project to promote more tolerance for religious diversity and rein in the forces of politico-religious extremism in the kingdom, leading to the establishment of National Dialogue. In the summer of 2003, Abdullah threw his considerable weight behind the creation of a national dialogue that brought leading religious figures together, including a highly publicized meeting attended by the kingdom's preeminent Shi'i scholar Hasan al-Saffar, as well as a group of Sunni clerics that had previously expressed their loathing for the Shi'i minority.


title: Abdullah of Saudi Arabia

text: Abdullah succeeded to the throne upon the death of his half-brother King Fahd. He was formally enthroned on 2 August 2005.


title: Abdullah of Saudi Arabia

text: In 2005, Abdullah implemented a government scholarship program to send young Saudi men and women abroad for undergraduate and postgraduate studies in different universities around the world. The program offered funds for tuition and living expenses up to four years. It is estimated that more than 70,000 young Saudis studied abroad in more than 25 countries, with the United States, England, and Australia as top three destinations aimed for by the students. There are more than 22,000 Saudi students studying in the United States, exceeding pre-9/11 levels. Public health engagement included breast cancer awareness and CDC cooperation to set up an advanced epidemic screening network to protect 2010's three million Hajj pilgrims.


title: Abdullah of Saudi Arabia

text: In 2005, Abdullah declared that the national day of the country, 23 September, would be a public holiday in an attempt to reduce the influence of religious figures and some of the social restrictions. It was criticized by the religious figures who argued that such celebration was not part of Islam.


title: Abdullah of Saudi Arabia

text: Abdullah implemented many reform measures. He re-shuffled the ministry of education's leadership in February 2009 by bringing in his pro-reform son-in-law, Faisal bin Abdullah, as the new minister. He also appointed Nora Al Fayez, a U.S.-educated former teacher, as deputy education minister in charge of a new department for female students.


title: Abdullah of Saudi Arabia

text: He brought about a top-to-bottom restructuring of the country's courts to introduce, among other things, review of judicial decisions and more professional training for Shari'a judges. He developed a new investment promotion agency to overhaul the once-convoluted process of starting a business in Saudi Arabia and created a regulatory body for capital markets. He also promoted the construction of the King Abdullah University for Science and Technology (the country's new flagship and controversially co-ed institution for advanced scientific research). Abdullah invested in educating the workforce for future jobs. The Saudi government also encouraged the development of non-hydrocarbon sectors in which the Kingdom had a comparative advantage, including mining, solar energy, and religious tourism. The Kingdom's 2010 budget reflected these priorities—about 25 percent was devoted to education alone—and amounts to a significant economic stimulus package.


title: Abdullah of Saudi Arabia

text: The response of his administration to homegrown terrorism was a series of crackdowns including raids by security forces, arrests, torture and public beheadings. He vowed to fight terrorist ideologies within the country. He also made the protection of Saudi Arabia's critical infrastructure a top security priority. His strategy against terrorism was two-pronged: he attacked the roots of the extremism that fed Al-Qaida through education and judicial reforms to weaken the influence of the most reactionary elements of Saudi Arabia's religious establishment.


title: Abdullah of Saudi Arabia

text: In August 2010, Abdullah decreed that only officially approved religious scholars associated with the Senior Council of Ulema would be allowed to issue fatwas. Similar decrees since 2005 were previously seldom enforced. Individual fatwas relating to personal matters were exempt from the royal decree. The decree also instructed the Grand Mufti to identify eligible scholars.


title: Abdullah of Saudi Arabia

text: In light of the Arab Spring, Abdullah laid down a $37 billion (€32.8 billion) programme of new spending including new jobless benefits, education and housing subsidies, debt write-offs, and a new sports channel. There was also a pledge to spend a total of $400 billion by the end of 2014 to improve education, health care and the kingdom's infrastructure. However, Saudi police arrested 100 Shiite protesters who complained of government discrimination. Later during the 2011–2012 Saudi Arabian protests, in September 2011, the King announced women's right to vote in the 2015 municipal council elections, a first significant reform step in the country since the protests. He also stated that women would become eligible to take part in the unelected shura.


title: Abdullah of Saudi Arabia

text: In January 2012, Abdullah dismissed the head of Saudi Arabia's powerful religious police, replacing him with a more moderate cleric, state news agency SPA reported, without giving reasons. Abdullatif Abdel Aziz al-Sheikh was named, in place of Sheikh Abdulaziz al Humain, to head the Commission for the Promotion of Virtue and Prevention of Vice. Abdullah had appointed Humain in 2009 to head the "mutaween," which ensures the strict application of the country's ultra-conservative version of Islam, as a step towards reforming it. Humain hired consultants to restructure the organisation, met local human rights groups and consulted professional image-builders in a broad public relations campaign. Under his leadership the commission also investigated and punished some "out-of-control" officers for misbehaviour.


title: Abdullah of Saudi Arabia

text: In July 2012, Saudi Arabia announced that it would allow its women athletes to compete in the Olympics for the first time and that the country's Olympic Committee would "oversee participation of women athletes who can qualify". The decision ended speculation that the entire Saudi team might have been disqualified on grounds of gender discrimination. The public participation of women in sport was still fiercely opposed by many Saudi religious conservatives. There had been almost no public tradition of women participating in sport in the country. Saudi officials said that, if successful in qualifying, female competitors would be dressed "to preserve their dignity". On 11 January 2013, Abdullah appointed thirty women to the Consultative Assembly or Shura Council and modified the related law to mandate that no less than 20 percent of 150 members would be women.


title: Abdullah of Saudi Arabia

text: In August 2013, the Saudi cabinet, for the first time, approved a law making domestic violence a criminal offence. The law calls for a punishment of up to a year in prison and a fine of up to 50,000 riyals (€11,500/US$13,000). The maximum punishments could be doubled for repeat offenders. The law criminalizes psychological, sexual as well as physical abuse. It also includes a provision obliging employees to report instances of abuse in the workplace to their employer. The move followed a Twitter campaign. The new laws were welcomed by Saudi women's rights activists, although some expressed concerns that the law could not be implemented successfully without new training for the judiciary, and that the tradition of male guardianship would remain an obstacle to prosecutions.


title: Abdullah of Saudi Arabia

text: In November 2007, Abdullah visited Pope Benedict XVI in the Apostolic Palace, being first Saudi monarch to do so. In March 2008, he called for a "brotherly and sincere dialogue between believers from all religions".


title: Abdullah of Saudi Arabia

text: In June 2008, he held a conference in Mecca to urge Muslim leaders to speak with one voice with Jewish and Christian leaders. He discussed with, and obtained approval from, Saudi and non-Saudi Islamic scholars to hold the interfaith dialogue. In the same month, Saudi Arabia and Spain agreed to hold the interfaith dialogue in Spain. The historic conference finally took place in Madrid in July 2008, wherein religious leaders of different faiths participated, and which later led to the 2010 proclamation of World Interfaith Harmony Week.


title: Abdullah of Saudi Arabia

text: He had never previously made overtures for dialogue with eastern religious leaders, such as Hindus and Buddhists. The Mecca conference discussed a paper on dialogue with monotheists—highlighting the monotheistic religions of southeast Asia, including Sikhism—in the third axis of the fourth meeting, titled "With Whom We Talk," presented by Sheikh Badrul Hasan Al Qasimi. The session was chaired by Ezz Eddin Ibrahim, cultural adviser to the president of the United Arab Emirates. The session also discussed a paper presented on coordination among Islamic institutions on Dialogue by Abdullah bin Omar Nassif, Secretary General of the World Islamic Council for Preaching and Relief and a paper on dialogue with divine messages, presented by Professor Mohammed Sammak—Secretary General of the Islamic Spiritual Summit in Lebanon.


title: Abdullah of Saudi Arabia

text: In November 2008, he and his government arranged discussion at the United Nations General Assembly to "promote dialogue among civilizations, cultures and peoples, as well as activities related to a culture of peace" and calling for "concrete action at the global, regional and subregional levels." It brought together Muslim and non-Muslim nations to eradicate preconceptions as to Islam and terrorism, with world leaders—including former UK Prime Minister Tony Blair, Israeli President Shimon Peres, US President George W. Bush and King Abdullah II of Jordan—attending.


title: Abdullah of Saudi Arabia

text: In 2011, an agreement for the establishment of the Abdullah bin Abdulaziz International Centre for Interreligious and Intercultural Dialogue in Vienna was signed between the governments of Austria, Spain, and Saudi Arabia. The official opening of the centre was in November 2012, with foreign minister Saud Al Faisal as its first general secretary and Austria's former federal justice minister Claudia Bandion-Ortner as the first deputy general secretary.


title: Abdullah of Saudi Arabia

text: Abdullah called for the establishment of an Arab common market in January 2011. Saudi foreign minister, Saud bin Faisal, stated that the Arab Customs Union would be ready by 2015, and that by 2017 the common market would also be in place. There have been intensive efforts to link Arab countries with a railway system and an electricity power grid. Work on the power grid project has started in some Arab countries.


title: Abdullah of Saudi Arabia

text: Abdullah had long been pro-American and a longtime close ally of the United States. In October 1976, as Prince Abdullah was being trained for greater responsibility in Riyadh, he was sent to the United States to meet with President Gerald Ford. He again traveled to the United States as Crown Prince in October 1987, meeting Vice President George H. W. Bush. In September 1998, Crown Prince Abdullah made a state visit to the United States to meet in Washington with President Bill Clinton. In September 2000, he attended millennium celebrations at the United Nations in New York City. In April 2002, Crown Prince Abdullah made a state visit to the United States with President George W. Bush and he returned again in April 2005 with Bush. In April 2009, at a summit for world leaders President Barack Obama met with Abdullah, while in June 2009 he hosted President Obama in Saudi Arabia. In turn, Obama hosted the King at the White House in the same month.


title: Abdullah of Saudi Arabia

text: Abdullah showed great support for Obama's presidency. "Thank God for bringing Obama to the presidency", he said, adding that Obama's election created "great hope" in the Muslim world. He stated, "We (the US and Saudi Arabia) spilled blood together" in Kuwait and Iraq, that Saudi Arabia valued this tremendously and that friendship could be a difficult issue that requires work, but that the United States and Saudi Arabia had done it for 70 years over three generations. "Our disagreements don't cut to the bone", he stated. He was the leading gift-giver to the US president and his office in his first two years in office, his gifts totaling more than $300,000. A ruby and diamond jewelry set, given by the king and accepted by First Lady Michelle Obama on behalf of the United States, was worth $132,000. However, according to US federal law, gifts of such nature and value are accepted "on behalf of the United States" and are considered property of the US government.


title: Abdullah of Saudi Arabia

text: The Bush administration ignored advice from him and Saudi foreign minister Saud Al Faisal against invading Iraq. However, other sources said that many Arab governments were only nominally opposed to the Iraq invasion because of popular hostility. Before becoming king, Prince Abdullah was thought to be completely against the US invasion of Iraq; this, however, was not the case. Riyadh provided essential support to the United States during the war and proved that "necessity does lead to some accommodations from time to time". The King expressed a complete lack of trust in Iraqi Prime Minister Nouri Al Maliki and held out little hope for improved Saudi-Iraqi relations as long as Al Maliki remained in office. Abdullah told an Iraqi official about Al Maliki, "You and Iraq are in my heart, but that man is not."


title: Abdullah of Saudi Arabia

text: In September 2014, following the spread of the Islamic State of Iraq and the Levant (ISIL), he issued a statement, "From the cradle of revelation and the birthplace of the Prophet Muhammad, I call on leaders and scholars of the Islamic nation to carry out their duty towards God Almighty, and to stand in the face of those trying to hijack Islam and present it to the world as a religion of extremism, hatred, and terrorism, and to speak the word of truth, and not fear anybody. Our nation today is passing through a critical, historic stage, and history will be witness against those who have been the tool exploited by the enemies to disperse and tear the nation and tarnish the pure image of Islam".


title: Abdullah of Saudi Arabia

text: In 2006, Iranian Supreme Leader Khamenei had sent his adviser Ali Akbar Velayati with a letter asking for Abdullah's agreement to establish a formal back channel of communication between the two leaders. Abdullah said he had agreed, and the channel was established, with Velayati and Saud Al Faisal as the points of contact. In the ensuing years, the King noted, the channel had never been used.


title: Abdullah of Saudi Arabia

text: In April 2008, according to a US cable released by WikiLeaks, Abdullah had told the US Ambassador to Iraq, Ryan Crocker, and General David Petraeus to "cut off the head of the snake". Saudi Arabia's Ambassador to Washington, Adel al-Jubeir, "recalled the King's frequent exhortations to the US to attack Iran" and to put an end to that country's nuclear program. Abdullah asserted that Iran was trying to set up Hezbollah-like organizations in African countries, observing that the Iranians didn't think they were doing anything wrong and didn't recognize their mistakes. He said that the Iranians "launch missiles with the hope of putting fear in people and the world". The King described his conversation with Iranian foreign minister Mottaki as "a heated exchange, frankly discussing Iran's interference in Arab affairs". When challenged by the King on Iranian meddling in Hamas affairs, Mottaki apparently protested that "these are Muslims". "No, Arabs", countered the King. "You as Persians have no business meddling in Arab matters". Abdullah said he would favor Rafsanjani in an Iranian election.


title: Abdullah of Saudi Arabia

text: He told General Jones that Iranian internal turmoil presented an opportunity to weaken the regime—which he encouraged—but he also urged that this be done covertly, stressing that public statements in support of the reformers were counterproductive. The King assessed that sanctions could help weaken the government, but only if they are strong and sustained.


title: Abdullah of Saudi Arabia

text: Saudi Arabia, by the endorsement of the Gulf Cooperation Council, sent 1,200 troops to Bahrain to protect industrial facilities, resulting in strained relations with the United States. The military personnel were part of the Peninsula Shield Force, which is stationed in Saudi Arabia, but not affiliated to one country alone.


title: Abdullah of Saudi Arabia

text: In December 2010, leaked diplomatic cables published by WikiLeaks revealed that Abdullah wanted all released detainees from the Guantanamo Bay detention camp to be tracked using an implanted microchip, in a way similar to race horses. The King made the private suggestion during a meeting in Riyadh in March 2009 with White House counterterrorism adviser, John O. Brennan. Brennan replied that "horses don't have good lawyers" and that such a proposal would "face legal hurdles" in the United States.


title: Abdullah of Saudi Arabia

text: Since Abdullah's visit to Beijing in January 2006, Saudi-Chinese relations have focused predominantly on energy and trade. The king's visit was the first by a Saudi head of state to China since the two countries established diplomatic ties in 1990. Bilateral trade with China has more than tripled, and China would soon be Saudi Arabia's largest importer. Saudi Arabia also committed significant investments in China, including the $8 billion Fujian refinery. Based on a WikiLeaks cable, the King told the Chinese that it was willing to effectively trade a guaranteed oil supply in return for Chinese pressure on Iran not to develop nuclear weapons.


title: Abdullah of Saudi Arabia

text: In late March 2011, Abdullah sent Bandar bin Sultan, Secretary General of the National Security Council, to China to gain its support regarding Saudi Arabia's attitude towards the Arab Spring. In turn, lucrative arms contracts were secretly offered to China by the Kingdom. Furthermore, Abdullah believed that China as well as India were the future markets for Saudi energy.


title: Abdullah of Saudi Arabia

text: Abdullah visited Turkey in August 2006 being the first Saudi king who paid an official visit there. In November 2009, Abdullah was received by Nicolas Sarkozy, who committed various diplomatic faux pas. The diplomatic relationship Jacques Chirac had with Saudi Arabia was not evident with Sarkozy. In January 2011, the Kingdom granted asylum to the ousted Tunisian leader, Zine El-Abidine Ben Ali, under conditions of no further political involvement. According to leaked cables, Abdullah was more receptive than Crown Prince Sultan to former Yemeni President Saleh.


title: Abdullah of Saudi Arabia

text: Abdullah supported renewed diplomatic relations with the Syrian government and Bashar al-Assad. They met in Damascus on 7 October 2009. In addition, Assad attended the opening of King Abdullah University of Science and Technology in October 2009. Relations between Syria and Saudi Arabia deteriorated as a result of the Syrian Civil War. In August 2011, Abdullah recalled the Saudi Ambassador from Damascus due to the political unrest in Syria and closed its embassy.


title: Abdullah of Saudi Arabia

text: In December 2011, Abdullah called on leaders of the Gulf Cooperation Council to strengthen their alliance into a united "single entity" as they confront threats to national security. "I ask you today to move from a stage of cooperation to a stage of union in a single entity", Abdullah said at the opening session of a GCC meeting in Riyadh in comments aired on Saudi state television. "No doubt, you all know we are targeted in our security and stability".


title: Abdullah of Saudi Arabia

text: On 16 February 2003, "Parade" magazine's David Wallechinsky rated King Fahd and Crown Prince Abdullah as the second worst dictators in the world. Most of this criticism stems from the fact that most of Saudi citizens live under a strict Wahhabist interpretation of Sharia law, which mandates the amputation of hands as a punishment for theft and floggings for crimes like drunkenness. Execution by public beheading is common for murder, rape, drug trafficking and witchcraft, and Abdullah's policies towards the rights of women have also been criticized. In a slight rebuff to accusations of human rights violations, Saudi inmates of Najran Province sent the King well-wishes from jail and wished him a speedy recovery.


title: Abdullah of Saudi Arabia

text: Abdullah has also been criticized for his policies on religious freedom and the Saudi government allegedly has arrested Shiite pilgrims on the Hajj. On 24 January 2007, Human Rights Watch sent an open letter to Abdullah asking him to cease religious persecution of the Ahmadi faith in Saudi Arabia. Two letters were sent in November 2006 and February 2007 asking him to remove the travel ban on critics of the Saudi government. Human Rights Watch has not yet indicated whether they have received any response to these letters.


title: Abdullah of Saudi Arabia

text: On 30 October 2007, during a state visit to the UK, Abdullah was accused by protestors of being a "murderer" and a "torturer". Concerns were raised about the treatment of women and homosexuals by the Saudi kingdom and over alleged bribes involving arms deals between Saudi Arabia and the UK.


title: Abdullah of Saudi Arabia

text: Abdullah's heir apparent was his half-brother Crown Prince Sultan until the latter's death on 22 October 2011. The title of Crown Prince then passed to Prince Sultan's full-brother, Nayef, until his death in Geneva, Switzerland, on 16 June 2012, while undergoing medical tests for an undisclosed ailment. His third heir apparent was his half-brother Salman, who was named as crown prince on 18 June 2012, and would succeed him in 2015.


title: Abdullah of Saudi Arabia

text: In 2006, Abdullah set up the Allegiance Council, a body that is composed of the sons and grandsons of Saudi Arabia's founder, King Abdulaziz, to vote by a secret ballot to choose future kings and crown princes. The council's mandate was not to have started until after the reigns of both Abdullah and Prince Sultan were over. It was not clear what was to happen when Prince Sultan died before the end of Abdullah's reign, leaving a question as to whether the council would vote for a new crown prince, or whether Prince Nayef would automatically fill that position. Despite such concerns, Prince Nayef was appointed Crown Prince on 27 October 2011 after consultation with the Allegiance Council by Abdullah.


title: Abdullah of Saudi Arabia

text: In November 2010, Prince Nayef chaired a cabinet meeting because of the deterioration of the King's health. During the same month, Abdullah transferred his duties as Commander of the Saudi National Guard to his son Prince Mutaib. Abdullah is credited with building up the once largely ceremonial unit into a modern 260,000-strong force that is a counterweight to the army. The Guard, which was Abdullah's original power base, protects the royal family. This was suggested as an apparent sign that the elderly monarch was beginning to lessen some of his duties.


title: Abdullah of Saudi Arabia

text: Abdullah was Commander of the Saudi National Guard from 1963 to 2010. He was Chairman of the Saudi Supreme Economic Council until 2009. He also continued to be the President of the High Council for Petroleum and Minerals, President of the King Abdulaziz Center For National Dialogue, Chairman of the Council of Civil Service, and head of the Military Service Council until his death in 2015.


title: Abdullah of Saudi Arabia

text: Abdullah mostly married women who had tribal backgrounds. He had 36 children with about 30 different. His wives, grandchildren, and great grandchildren have been subject to travel bans since 2017.


title: Abdullah of Saudi Arabia

text: Abdullah married the daughters of the al Shalan of Anizah, al Fayz of Bani Sakhr, and al Jarbah of the Iraqi branch of the Shammar tribe. He had about 30 wives, and fathered 36 children.


title: Abdullah of Saudi Arabia

text: Munira bint Abdullah Al Sheikh was the mother of King Abdullah's eldest living son, Prince Khaled. One of Abdullah's wives was the sister of Rifaat al-Assad's wife, Aida Fustuq, with whom he had two children, Adila and Abdulaziz. They divorced later. His another wife was from the Al Sudairi clan, Sultana bint Abdulaziz bin Ahmed Al Sudairi. King Abdullah also married Jawahir bint Ali Hussein from the Al Jiluwi clan, with whom he had two children, Princess Anoud and Prince Saud. Tathi bint Mishan Al Faisal Al Jarba gave birth to another six of his children, including Prince Mishaal, Prince Turki, and Princess Oraib. Another wife was Malka bint Saud bin Zaid Al Jarba Al Choumri, and they had three children: Prince Saad, Princess Sahab and Prince Sultan. Haifa Al Muhanna was the mother of Abdullah's youngest child, Prince Bandar. A prominent wife of the King, Hessa bint Trad Al Shaalan, is the mother of Prince Faisal and Princess Abeer among others.


title: Abdullah of Saudi Arabia

text: Abdullah had thirty-six children, sixteen of whom are male. His eldest son, Mutaib, died at a young age. His second eldest son, Prince Khalid, was deputy commander of the Saudi Arabian National Guard West until 1992. His third son, Prince Mutaib, is former commander and former minister of the National Guard. Prince Mishaal was governor of the Makkah Province between 2013 and 2015. Prince Abdulaziz was the king's former Syria adviser and was deputy foreign affairs minister from 2011 to 2015. Prince Faisal was the head of the Saudi Arabian Red Crescent Society. Abdullah's seventh son, Prince Turki, was a pilot in the Royal Saudi Air Force and served as governor of the Riyadh Province from 2014 to 2015). His youngest son, Prince Bandar, was born in 1999, when Abdullah was about 75 years old.


title: Abdullah of Saudi Arabia

text: In October 2015, King Abdullah's son Prince Majid was arrested in Los Angeles on suspicion of "forcing oral copulation", amid allegations that he had been unlawfully imprisoning, threatening, sexually harassing, and assaulting employees while under the influence of cocaine and alcohol. He was released on bail, and felony charges were dropped for lack of evidence; a civil suit filed by three housekeepers continued. Another son, Mohammed, is married to Nouf bint Nayef, a daughter of the Prince Nayef and Maha bint Mohammed Al Sudairi.


title: Abdullah of Saudi Arabia

text: Abdullah had twenty daughters. Princess Adila married Faisal bin Abdullah, who served as minister of education. She is one of the few Saudi princesses with a semi-public role, and is a known advocate of a woman's right to drive. She was also known as "her father's public face". On 6 June 2011, Abdullah's daughter Princess Sahab (born 1993) married Khalid bin Hamad Al Khalifa, son of Bahraini King Hamad bin Isa Al Khalifa. Another daughter, Abeer, is the wife of Fahd bin Turki Al Saud. Sara bint Abdullah married Turki bin Talal and they had one son, Abdulaziz. She later married Fahd bin Badr, with whom she has five children.


title: Abdullah of Saudi Arabia

text: One of Abdullah's daughters, Noura, died in 1990 in a car accident near Riyadh airport. She was married to Sultan bin Turki Al Saud. Abdullah's daughter Fayza is the mother of Prince Saud bin Abdulaziz bin Nasser Al Saud, who was accused of murdering his servant Bandar Abdulaziz in London in 2010. His daughter, Hayfa, was featured on the cover of "Vogue Arabia" magazine's June 2018 issue. Salman bin Abdulaziz bin Salman, a member of the Al Kabir branch of Al Saud, is married to a daughter of King Abdullah, Oraib, who is the full sister of Turki bin Abdullah. Another daughter, Seeta, was married to Faisal bin Thamir, a son of Thamir bin Abdulaziz Al Saud.


title: Abdullah of Saudi Arabia

text: From his marriage to Al Anoud Al Fayez (arranged when she was 15 without her having ever met him), whom he later divorced, Abdullah had four daughters— Sahar, Maha, Hala and Jawahir. They have been under house arrest for several years, and are not allowed to leave the country. After media releases in March 2014, Sahar and Jawahir received no food or clean water for 25 days, lost 10 kg each and their mother carried out weekly protests in front of the Saudi Arabian embassy in London. They spoke and released a video while under house arrest, pleading for help from the international community. After 2014, media reports of their condition dried up. Princess Hala died on 30 September 2021 at age 47, and there was no mention about the cause of her death. Funeral prayer for her was performed after evening prayers at the Grand Mosque in Mecca.


title: Abdullah of Saudi Arabia

text: The King had curtailed his activities from June 2010 with no clear explanation. Diplomats said there had been uncertainty about the extent of his health problems since Abdullah canceled a visit to France. In a television appearance in which he was seen to use a cane, Abdullah said he was in good health but had something "bothering" him. In a visit by US diplomats to Saudi Arabia in April 2014 the Saudi King was seen connected to breathing tubes during talks, indicating increasing health problems.


title: Abdullah of Saudi Arabia

text: From 2010 to 2012 Abdullah had four back surgeries. The first two of the surgeries were in New York, one in 2010 for a slipped disk and a blood clot pressing on nerves in his back and a second to stabilize vertebrae in 2011. The third one was in Riyadh in 2011. And the last one was also in Riyadh on 17 November 2012.


title: Abdullah of Saudi Arabia

text: In November 2010, his back problems came to light in the media. He had an "accumulation of blood" around the spinal cord. He suffered from a herniated disc and was told to rest by doctors. To maintain the Kingdom's stability, Crown Prince Sultan returned from Morocco during the King's absence. The King was admitted to NewYork–Presbyterian Hospital after a blood clot complicated a slipped disc and underwent successful back surgery. The lead surgeon was Muhammad Zaka, who probably removed the herniated disk and performed a lumbar fusion. He subsequently had another successful surgery in which surgeons "stabilized a number of vertebras". He left the hospital on 22 December 2010 and convalesced at The Plaza in New York City. On 22 January 2011, he left the United States for Morocco, and returned to the Kingdom on 23 February 2011.


title: Abdullah of Saudi Arabia

text: Abdullah left Saudi Arabia on "special leave" on 27 August 2012. "Al Quds" reported that he had an operation at Mount Sinai Hospital, New York, on or before 4 September 2012, following a heart attack. However, there was no official report on this alleged operation—instead, it was announced that the King went on a private trip to Morocco, where he was known to frequent. The King returned to Saudi Arabia from Morocco on 24 September. Nearly two months later, in November 2012, Abdullah underwent another back surgery in Riyadh and left hospital on 13 December 2012.


title: Abdullah of Saudi Arabia

text: On 2 January 2015, Abdullah was hospitalized in Riyadh for pneumonia and died on 23 January at the age of 90. In accordance with Islamic tradition, his funeral was held the same day, a public ceremony at the Grand Mosque of Riyadh before burial in an unmarked grave at the Al Oud cemetery. Three days of national mourning were declared, in which flags would fly at half-mast. Flags were also flown half-mast at Buckingham Palace and Westminster Abbey in London.


title: Abdullah of Saudi Arabia

text: In 2012 Abdullah was named as the most influential Muslim among 500 Muslims for the previous 4 years. In December 2012, "Forbes" named him as the seventh-most-powerful figure in its list of the "World's Most Powerful People" for 2012, being the sole Arab in the top ten.


title: Abdullah of Saudi Arabia

text: In 2011, the financial magazine "Forbes" estimated the documentable wealth of King Abdullah and his immediate family at US$, making him one of the world's richest monarchs. One estimate places his wealth at US$18 billion, making him the third-wealthiest head of state in the world.


title: Abdullah of Saudi Arabia

text: King Abdullah was an expert equestrian in his youth. His stables were considered the largest in Saudi Arabia, with over 1,000 horses spread throughout five divisions led by his son Prince Mutaib. The King also owned Janadria Farm, a large complex located in the suburbs of Riyadh.


title: Abdullah of Saudi Arabia

text: For holidays, the King maintained a large palace complex with several residential compounds in Casablanca, Morocco. It is equipped with two heliports and is surrounded by large mansions on 133 acres of vegetation.


title: Abdullah of Saudi Arabia

text: While still Crown Prince, Abdullah paid for the separation surgery of a pair of Polish conjoined twins, which took place at the King Abdulaziz Medical City in Riyadh on 3 January 2005.


title: Abdullah of Saudi Arabia

text: He donated $50 million in cash and $10 million worth of relief materials for the 2008 Sichuan earthquake in China.


title: Abdullah of Saudi Arabia

text: He donated $10 billion to the endowment fund of the King Abdullah University of Science and Technology in May 2008.


title: Abdullah of Saudi Arabia

text: Abdullah received a number of international high orders. Most notably, he was an honoured knight of the strictly Roman Catholic Order of the Golden Fleece (the Spanish branch), which caused some controversy.


title: Abdullah of Saudi Arabia

text: In April 2012, he was awarded by the United Nations a gold medal for his contributions to intercultural understanding and peace initiatives.


title: Old Style and New Style dates

text: Old Style (O.S.) and New Style (N.S.) indicate dating systems before and after a calendar change, respectively. Usually, this is the change from the Julian calendar to the Gregorian calendar as enacted in various European countries between 1582 and 1923.


title: Old Style and New Style dates

text: In England, Wales, Ireland and Britain's American colonies, there were two calendar changes, both in 1752. The first adjusted the start of a new year from Lady Day (25 March) to 1 January (which Scotland had done from 1600), while the second discarded the Julian calendar in favour of the Gregorian calendar, removing 11 days from the September 1752 calendar to do so. To accommodate the two calendar changes, writers used dual dating to identify a given day by giving its date according to both styles of dating.


title: Old Style and New Style dates

text: For countries such as Russia where no start of year adjustment took place, O.S. and N.S. simply indicate the Julian and Gregorian dating systems. Many Eastern Orthodox countries continue to use the older Julian calendar for religious purposes.


title: Old Style and New Style dates

text: In the Kingdom of Great Britain and its possessions, the Calendar (New Style) Act 1750 introduced two concurrent changes to the calendar. The first, which applied to England, Wales, Ireland and the British colonies, changed the start of the year from 25 March to 1 January with effect from "the day after 31 December 1751". (Scotland had already made this aspect of the changes, on 1 January 1600.) The second (in effect) adopted the Gregorian calendar in place of the Julian calendar. Thus "New Style" can either refer to the start of year adjustment, or to the adoption of the Gregorian calendar, or to the combination of the two.


title: Old Style and New Style dates

text: When recording British history, it is usual to quote the date as originally recorded at the time of the event, but with the year number adjusted to start on 1 January. The latter adjustment may be needed because the start of the civil calendar year was not always 1 January and was altered at different times in different countries. From 1155 to 1752, the civil or legal year in England began on 25 March (Lady Day); so for example, the execution of Charles I was recorded at the time in Parliament as happening on 30 January 1648 (Old Style). In newer English language texts this date is usually shown as "30 January 1649" (New Style). The corresponding date in the Gregorian calendar is 9 February 1649, the date by which his contemporaries in some parts of continental Europe would have recorded his execution.


title: Old Style and New Style dates

text: The O.S./N.S. designation is particularly relevant for dates which fall between the start of the "historical year" (1 January) and the legal start date, where different. This was 25 March in England, Wales, Ireland and the colonies until 1752 and until 1600 in Scotland.


title: Old Style and New Style dates

text: In Britain, 1 January was celebrated as the New Year festival from as early as the 13th century, despite the recorded (civil) year not incrementing until 25 March. but the "year starting 25th March was called the Civil or Legal Year, although the phrase Old Style was more commonly used". To reduce misunderstandings about the date, it was normal even in semi-official documents such as parish registers to place a statutory new year heading after 24 March (for example "1661") and another heading from the end of the following December, "1661/62", a form of dual dating to indicate that in the following twelve weeks or so, the year was 1661 Old Style but 1662 New Style. Some more modern sources, often more academic ones (e.g. the History of Parliament) also use the "1661/62" style for the period between 1 January and 24 March for years before the introduction of the New Style calendar in England.


title: Old Style and New Style dates

text: Through the enactment of the Calendar (New Style) Act 1750, the Kingdom of Great Britain, the Kingdom of Ireland and the British Empire (including much of what is now the eastern part of the United States and Canada) adopted the Gregorian calendar in 1752, by which time it was necessary to correct by 11 days. Wednesday, 2 September 1752, was followed by Thursday, 14 September 1752. Claims that rioters demanded "Give us our eleven days" grew out of a misinterpretation of a painting by William Hogarth.


title: Old Style and New Style dates

text: Beginning in October of 1582, the Gregorian calendar replaced the Julian in Catholic countries. This change was implemented subsequently in Protestant and Eastern Orthodox countries, usually at much later dates and, in the latter case, only as the civil calendar. Consequently, when Old Style and New Style notation is encountered, the British adoption date is not necessarily intended. The 'start of year' change and the calendar system change were not always adopted concurrently. Similarly, civil and religious adoption may not have happened at the same time or even at all. In the case of Eastern Europe, for example, all of those assumptions would be incorrect.


title: Old Style and New Style dates

text: Other countries in Eastern Orthodoxy eventually adopted Gregorian (or new style) dating for their civil calendars but most of these continue to use the Julian calendar for religious purposes. Greece was the last to do so, in 1923. Here too, there is a 13-day difference between Old Style and New Style dates in modern Greek history.


title: Old Style and New Style dates

text: Romania officially adopted the Gregorian calendar on 1 April 1919, which became 14 April 1919. This was commemorated in 2019 by the National Bank of Romania through the release of a commemorative coin of 10silver "lei".


title: Old Style and New Style dates

text: In Russia, new style dates came into use in early 1918, when 31 January 1918 was followed by 14 February 1918: there is a 13-day difference between Old Style and New Style dates since 1 March 1900.


title: Old Style and New Style dates

text: It is common in English-language publications to use the familiar Old Style and/or New Style terms to discuss events and personalities in other countries, especially with reference to the Russian Empire and the very beginning of Soviet Russia. For example, in the article "The October (November) Revolution," the "Encyclopædia Britannica" uses the format of "25 October (7 November, New Style)" to describe the date of the start of the revolution.


title: Old Style and New Style dates

text: The European colonies of the Americas adopted the new style calendar when their mother countries did. In what is now the continental United States, the French and Spanish possessions did so about 130 years earlier than the British colonies. In practice, however, most surviving written records of what is now Canada and the United States are from the 20 mainland British colonies, where the British Calendar Act of 1751 was applied twenty-four years before the United States declared independence. Canadian records also include documents of New France that reflect the New Style, as France adopted it in 1582, but the language used in the record is likely to be a good indicator of which calendar was being used for the dates given. The same logic applies to the Caribbean islands.


title: Old Style and New Style dates

text: In Alaska, the change took place after the United States purchased Alaska from Russia. Friday, 6 October 1867 was followed by Friday, 18 October. Instead of 12 days, only 11 were skipped, and the day of the week was repeated on successive days, because at the same time the International Date Line was moved, from following Alaska's eastern border with Yukon to following its new western border, now with Russia.


title: Old Style and New Style dates

text: Usually, the mapping of New Style dates onto Old Style dates with a start of year adjustment works well with little confusion for events before the introduction of the Gregorian calendar. For example, the Battle of Agincourt is well known to have been fought on 25 October 1415, which is Saint Crispin's Day. However, for the period between the first introduction of the Gregorian calendar on 15 October 1582 and its introduction in Britain on 14 September 1752, there can be considerable confusion between events in Continental Western Europe and in British domains. Events in Continental Western Europe are usually reported in English-language histories by using the Gregorian calendar. For example, the Battle of Blenheim is always given as 13 August 1704. However, confusion occurs when an event involves both. For example, William III of England arrived at Brixham in England on 5 November (Julian calendar), after he had set sail from the Netherlands on 11 November (Gregorian calendar) 1688.


title: Old Style and New Style dates

text: The Battle of the Boyne in Ireland took place a few months later on 1 July 1690 (Julian calendar). That maps to 11 July (Gregorian calendar), conveniently close to the Julian date of the subsequent (and more decisive) Battle of Aughrim on 12 July 1691 (Julian). The latter battle was commemorated annually throughout the 18th century on 12 July, following the usual historical convention of commemorating events of that period within Great Britain and Ireland by mapping the Julian date directly onto the modern Gregorian calendar date (as happens, for example, with Guy Fawkes Night on 5 November). The Battle of the Boyne was commemorated with smaller parades on 1 July. However, both events were combined in the late 18th century, and continue to be celebrated as "The Twelfth".


title: Old Style and New Style dates

text: Because of the differences, British writers and their correspondents often employed two dates, which is called dual dating, more or less automatically. Letters concerning diplomacy and international trade thus sometimes bore both Julian and Gregorian dates to prevent confusion. For example, Sir William Boswell wrote to Sir John Coke from The Hague a letter dated "12/22 Dec. 1635". In his biography of John Dee, "The Queen's Conjurer", Benjamin Woolley surmises that because Dee fought unsuccessfully for England to embrace the 1583/84 date set for the change, "England remained outside the Gregorian system for a further 170 years, communications during that period customarily carrying two dates". In contrast, Thomas Jefferson, who lived while the British Isles and colonies eventually converted to the Gregorian calendar, instructed that his tombstone bear his date of birth by using the Julian calendar (notated O.S. for Old Style) and his date of death by using the Gregorian calendar. At Jefferson's birth, the difference was eleven days between the Julian and Gregorian calendars and so his birthday of 2 April in the Julian calendar is 13 April in the Gregorian calendar. Similarly, George Washington is now officially reported as having been born on 22 February 1732, rather than on 11 February 1731/32 (Julian calendar).


title: Old Style and New Style dates

text: There is some evidence that the calendar change was not easily accepted. Many British people continued to celebrate their holidays "Old Style" well into the 19th century, a practice that the author Karen Bellenir considered to reveal a deep emotional resistance to calendar reform.


title: Old Style and New Style dates

text: The change arose from the realisation that the correct figure for the number of days in a year is not 365.25 (365 days 6 hours) as assumed by the Julian calendar but slightly less (c. 365.242 days): the Julian calendar has too many leap years. The consequence was that the basis for the calculation of the date of Easter, as decided in the 4th century, had drifted from reality. The Gregorian calendar reform also dealt with the accumulated difference between these figures, between the years 325 and 1582 by skipping 10 days to set the ecclesiastical date of the equinox to be 21 March, the median date of its occurrence at the time of the First Council of Nicea in 325.


title: Old Style and New Style dates

text: Countries that adopted the Gregorian calendar after 1699 needed to skip the additional day for each subsequent new century that the Julian calendar had added since then. When the British Empire did so in 1752, the gap had grown to eleven days; when Russia did so (as its civil calendar) in 1918, thirteen days needed to be skipped.


title: Old Style and New Style dates

text: The Latin equivalents, which are used in many languages, are "stili veteris" (genitive) or "stilo vetere" (ablative), abbreviated "st.v." and respectively meaning , and "stili novi" or "stilo novo", abbreviated "st.n." and meaning The Latin abbreviations may be capitalised differently by different users, e.g., "St.n." or "St.N." for "stili novi". There are equivalents for these terms in other languages as well, such as the German "a.St." (""alten Stils"" for O.S.).


title: Alexa Davalos

text: Alexa Davalos Dunas (born May 28, 1982) is an American actress. Her early role as Gwen Raiden on the fourth season of the TV series "Angel" (2002–03) was followed by some Hollywood films, including "The Chronicles of Riddick" (2004), "Feast of Love" (2007), "The Mist" (2007), "Defiance" (2008) and "Clash of the Titans" (2010). She has also appeared on the television series "Reunion" (2005–06) and in Frank Darabont's "Mob City" (2013). She starred as Juliana Crain, the main character in the Amazon Studios series "The Man in the High Castle" (2015–2019). She also plays Special Agent Kristin Gaines in the CBS drama series "" (2021–present).


title: Alexa Davalos

text: Davalos was born in Paris, France to American parents, photographer Jeff Dunas and actress Elyssa Davalos, daughter of actor Richard Davalos. Davalos spent most of her childhood in France and Italy, before settling in New York. She has stated "I tend to curse in French more often than I do in English."


title: Alexa Davalos

text: She is of Spanish and Finnish descent on her mother's side. Her father's family is Jewish (her paternal ancestors lived in Vilnius in Lithuania). She was raised "without much religion", though she attended Hebrew school for a time.


title: Alexa Davalos

text: Davalos struck out on her own at seventeen and moved to New York City. She supported herself by modeling for photographers like Peter Lindbergh. "I had a mission," she recalls. "I wanted to be out in the world, doing my own thing. Working in a theatre, I discovered that I really wanted to act." Her passion soon grew towards acting, and she attended the Off-Broadway Flea Theater in New York. She kept her acting plans from her family until her career started to take off.


title: Alexa Davalos

text: In 2002, Davalos co-starred with Charlie Hofheimer in the short film "The Ghost of F. Scott Fitzgerald", which screened at the 2002 Toronto International Film Festival. In September 2003, she was seen opposite Antonio Banderas in the HBO film "And Starring Pancho Villa as Himself". Davalos made her feature film debut in 2004 starring in "The Chronicles of Riddick" as Jack / Kyra.


title: Alexa Davalos

text: Davalos also appeared as the superhuman Gwen Raiden in three episodes of the TV show "Angel" and in 2005 co-starred in the Fox show "Reunion". In 2007, she was featured in the romantic drama "Feast of Love", which starred Greg Kinnear and Morgan Freeman. She also played Sally in "The Mist" (directed by Frank Darabont), co-starring Thomas Jane, Laurie Holden and Marcia Gay Harden.


title: Alexa Davalos

text: In 2008, Davalos co-starred as the love interest of Daniel Craig in the war film "Defiance", directed by Edward Zwick. She played Andromeda in the remake of "Clash of the Titans", alongside Sam Worthington, Ralph Fiennes and Liam Neeson. She did not return for the 2012 sequel, "Wrath of the Titans", due to a scheduling conflict.


title: Alexa Davalos

text: In 2013, she reunited again with Frank Darabont playing the female lead on the television series "Mob City". 2 years later, in 2015, she starred in "The Man in the High Castle" (2015–2019).


title: Alexa Davalos

text: In 2019, she has made a brief appearance in "The Punisher", along with star Jon Bernthal; both of whom were also in "Mob City" (2013).


title: Alexa Davalos

text: Davalos is a close friend of actresses Amanda Righetti and Chyler Leigh, and was Righetti's bridesmaid at her wedding. Davalos considers herself to be a "dork" and loves to travel and read. She guards her private life stating, "I think it's a choice. I think it's a conscious choice, and what you allow to affect you and what you don't."


title: Alexa Davalos

text: Davalos married actor Josh Stewart on May 19, 2019. Both were costars on the second season of the Netflix series "The Punisher".


title: Punjabis

text: The Punjabis (Punjabi: ; ਪੰਜਾਬੀ ; romanised as Panjābīs), are an Indo-Aryan ethnolinguistic group associated with the Punjab region of the Indian subcontinent, comprising areas of eastern Pakistan and northwestern India. They generally speak Standard Punjabi or various Punjabi dialects on both sides.


title: Punjabis

text: The ethnonym is derived from the term "Punjab" (Five rivers) in Persian to describe the geographic region of the northwestern part of the Indian subcontinent, where five rivers Beas, Chenab, Jhelum, Ravi, and Sutlej merge into the Indus River, in addition of the now-vanished Ghaggar.


title: Punjabis

text: The coalescence of the various tribes, castes and the inhabitants of the Punjab region into a broader common "Punjabi" identity initiated from the onset of the 18th century CE. Historically, the Punjabi people were a heterogeneous group and were subdivided into a number of clans called "biradari" (literally meaning "brotherhood") or "tribes", with each person bound to a clan. With the passage of time, tribal structures became replaced with a more cohesive and holistic society, as community building and group cohesiveness form the new pillars of Punjabi society.