The Human Heart

The human heart is about the size of that human being's fist and is located in the center of your chest, slightly to the left of your sternum (breastbone). As the body develops, the heart grows at the same rate as the fist. So an infant's heart and fist are about the same size at birth. The human heart is actually shaped like an upside-down pear. A double-layered membrane called the pericardium surrounds your heart like a sac. The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body.

There are four chambers inside the heart that fill with blood. Two of these chambers are called atria. The other two are called ventricles. The two atria form the curved top of the heart. The ventricles meet at the bottom of the heart to form a pointed base which points toward the left side of your chest. The left ventricle contracts most forcefully, so you can best feel your heart pumping on the left side of your chest.

The left side of the heart houses one atrium and one ventricle. The right side of the heart houses the others. A wall of muscle, called the septum, separates the right and left sides of the heart. The left ventricle is the largest and strongest chamber in your heart. The left ventricle's chamber walls are only about a half-inch thick, but they have enough force to push blood through the aortic valve and into your body.

Four valves regulate blood flow through your heart. 1) The mitral valve connects the left atrium with the left ventricle below it, allowing oxygen-rich blood from the lungs pass through. 2) The tricuspid valve connects the right atrium with the right ventricle. 3) The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries, which carry blood to your lungs to pick up oxygen. 4) The aortic valve opens the way for oxygen-rich blood to pass from the left ventricle into the aorta, which is the largest artery, delivering it to the rest of the body.

Electrical impulses that travels through nerves connected to the myocardium (heart muscle) cause the heart to contract. This electrical signal begins in the sinoatrial (SA) node, located at the top of the right atrium. The SA node is sometimes called the heart's natural pacemaker. An electrical impulse from this natural pacemaker travels through the muscle fibers of the atria and ventricles, causing them to contract. Although the SA node sends electrical impulses at a certain rate, the heart rate may still change depending on physical demands, stress, or hormonal factors.
From the moment of development through the moment of death, the heart pumps. The heart, therefore, has to be strong. The average heart's muscle, called cardiac muscle, contracts and relaxes about 70 to 80 times per minute without you ever having to think about it. As the cardiac muscle contracts it pushes blood through the chambers and into the vessels. The ventricles of the heart have two states: systole (contraction) and diastole (relaxation). During diastole blood fills the ventricles and during systole the blood is pushed out of the heart into the arteries.


How the human heart works

The Circulatory System

The circulatory system is a blood distribution network which is responsible for transporting nutrients, water, and oxygen throughout the entire body to your billions of body cells, carrying away wastes such as carbon dioxide that body cells produce. As blood circulates through the body, oxygen and nutrients diffuse from the blood into cells surrounding the capillaries, and carbon dioxide diffuses into the blood from the capillary cells. From a point of view of its performance, the circulatory System is divided into three major parts: coronary circulation, pulmonary circulation, and systemic circulation.

Coronary circulation: Coronary circulation refers to the movement of blood through the tissues of the heart. The circulation of blood through the heart is just one part of the overall circulatory system. Serious heart damage may occur if the heart tissue does not receive a normal supply of food and oxygen. The heart tissue receives nourishment through the capillaries located in the heart.

Pulmonary circulation: Pulmonary circulation is the portion of the circulatory system which carries carbondioxide-containing blood away from the heart to the lungs, and returns oxygenated blood back to the heart. This is just one phase of the overall circulatory system. Oxygen-depleted blood enters the right atrium of the heart and flows into the right ventricle where it is pumped through the pulmonary arteries to the lungs. Pulmonary veins return the now oxygen-rich blood to the heart, where it enters the left atrium before flowing into the left ventricle. From the left ventricle the oxygen-rich blood is pumped out via the aorta on to the rest of the body.

Systemic circulation: Systemic circulation is the portion of the circulatory system that carries oxygenated blood away from the heart to the rest of the body, and returns carbondioxide-containing blood back to the heart. Arteries always take blood away from the heart, regardless of their oxygenation, and veins always bring blood back. In general, arteries bring oxygenated blood to the tissues; veins bring deoxygenated blood back to the heart. In the case of the pulmonary vessels, however, the oxygenation is reversed: the pulmonary artery takes deoxygenated blood from the heart to the lungs, and oxygenated blood is pumped back through the pulmonary vein to the heart.

From an anantomical point of view, the circulatory system is made up of the heart and blood vessels. Together, these provide a continuous flow of blood to your body, supplying the tissues with oxygen and nutrients. Arteries carry blood away from the heart; veins return blood to the heart.

Hypertension (High Blood Pressure)

Hypertension, or high blood pressure, is a medical condition in which the blood pressure chronically rises above the normal levels. In current usage, the word hypertension refers to arterial hypertension. Normal blood pressure is around 120/80. Blood pressure between 120/80 and 139/89 is called "pre-hypertension", and a blood pressure of 140/90 or above is considered high. Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure. Even moderate elevation of arterial blood pressure leads to shortened life expectancy. In individuals older than 50 years, hypertension is considered to be present when a person's systolic blood pressure is consistently 140 mm Hg or greater.

Resistant hypertension is defined as the failure to reduce blood pressure to the appropriate level after taking a three-drug regimen. The American Heart Association released guidelines for treating resistant hypertension. Although some people report headaches, fatigue, dizziness, blurred vision, facial flushing, transient insomnia, it usually produces no symptoms in isolation as it is often confused with mental tension, stress and anxiety. Hypertension is rarely severe enough to cause symptoms, which surface when the systolic blood pressure is above 230mmHg and the diastolic over 120mmHg.

Hypertension often has several contributing factors. These include obesity, salt sensitivity, insulin resistance, genetics, age, stress, sedentary life. The risk of hypertension is 5 times higher in the obese as compared to those of normal weight and up to two-thirds of cases can be attributed to excess weight. Sodium is an environmental factor that has received the greatest attention. Approximately one third of the essential hypertensive population is responsive to sodium intake. This is due to the fact that increasing amounts of salt in a person's bloodstream causes the body to hold back fluids to equilibrate concentration gradient of salt between the cells and the bloodstream, increasing the pressure on the blood vessel walls.

Blood Pressure

Blood pressure is the pressure exerted by circulating blood on the walls of the arteries, and it constitutes one of the main vital signs. Blood pressure results from two forces. One is created by the heart as it pumps blood into the arteries and through the circulatory system. The other is the force of the arteries as they resist the blood flow.

The term blood pressure generally refers to arterial pressure, which is the pressure in the larger arteries, the blood vessels that take blood away from the heart. Arterial pressure is most commonly measured via a sphygmomanometer, which historically used the height of a column of mercury to reflect the circulating pressure. Today blood pressure values are reported in millimeters of mercury (mmHg), though aneroid and electronic sphygmomanometers do not use mercury.

The systolic arterial pressure is defined as the peak pressure in the arteries, which occurs when the heart contracts to pump blood to the body. The diastolic arterial pressure is the lowest pressure when the heart relaxes between beats. The average pressure throughout the cardiac cycle is reported as mean arterial pressure. The pulse pressure reflects the difference between the maximum and minimum pressures measured.

Typical values for a healthy adult human are approximately 120 mmHg systolic and 80 mmHg diastolic, written as 120/80 mmHg, and spoken as one twenty over eighty, with large individual variations. These measures of arterial pressure are not static, but undergo natural variations from one heartbeat to another and throughout the day. They also change in response to stress, nutritional factors, drugs, or disease.

Measurement of blood pressure: Arterial pressures can be measured invasively and non-invasively. The former is usually restricted to a hospital setting, while the latter is more common, simpler and quicker. The non-invasive method uses a stethoscope and a sphygmomanometer. This comprises an inflatable (Riva-Rocci) cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. The cuff is inflated manually by repeatedly squeezing a rubber bulb until the artery is completely occluded. Listening with the stethoscope to the brachial artery at the elbow, the examiner slowly releases the pressure in the cuff. When blood just starts to flow in the artery, the turbulent flow creates a pounding. The pressure at which this sound is first heard is the systolic blood pressure. The cuff pressure is further released; at the point when no sound can be heard is the diastolic arterial pressure.

Cystic Fibrosis

Cystic fibrosis (CF) is an inherited disease of the exocrine glands of the lungs, liver, pancreas, and intestines, causing progressive disability due to multisystem failure. Normally, mucus is watery. It keeps the linings of certain organs moist and prevents them from drying out or getting infected. But in cystic fibrosis, an abnormal gene causes mucus to become thick and sticky. Thick mucus production results in frequent lung infections. Diminished secretion of pancreatic enzymes is the main cause of poor growth, fatty diarrhea, and deficiency in fat-soluble vitamins. Males can be infertile due to the condition congenital bilateral absence of the vas deferens. Often, symptoms of CF appear in infancy and childhood. Meconium ileus is a typical finding in newborn babies with CF.

Cystic fibrosis is one of the most common life-shortening, inherited diseases. In the United States, 1 in 3,900 children are born with CF. It is most common among Mediterranean populations and Ashkenazi Jews, as one in twenty-two people of Mediterranean descent are carriers of one gene for CF, making it the most common genetic disease in these populations. Ireland has the highest rate of cystic fibrosis carriers in the world, 1 in 19.

The thick, sticky mucus can also block tubes, or ducts, in your pancreas. As a result, digestive enzymes that are produced by your pancreas cannot reach your small intestine. These enzymes help break down the food that you eat. Without them, your intestines cannot absorb fats and proteins fully. As a result nutrients leave your body unused, and you can become malnourished, as you may not get enough vitamins A, D, E, and K. You may also have intestinal gas, a swollen belly, and pain or discomfort.

Lung disease results from clogging the airways due to mucus buildup and resulting inflammation. Inflammation and infection cause injury to the lungs and structural changes that lead to a variety of symptoms. In the early stages, incessant coughing, copious phlegm production, and decreased ability to exercise are common. Many of these symptoms occur when bacteria that normally inhabit the thick mucus grow out of control and cause pneumonia. In later stages of CF, changes in the architecture of the lung further exacerbate chronic difficulties in breathing. Respiratory failure is the most common cause of death in people with CF.

Infertility affects both men and women. At least 97 percent of men with cystic fibrosis are sterile. These men make normal sperm but are missing the tube (vas deferens), which connects the testes to the ejaculatory ducts of the penis. Many men found to have congenital absence of the vas deferens during evaluation for infertility have a mild, previously undiagnosed form of CF. Some women have fertility difficulties due to thickened cervical mucus or malnutrition. In severe cases, malnutrition disrupts ovulation and causes amenorrhea.

The abnormal gene also causes your sweat to become extremely salty. As a result, when you perspire, your body loses large amounts of salt. This can upset the balance of minerals in your blood. The imbalance may cause you to have a heat emergency.

Most individuals with cystic fibrosis die young as there is no cure for CF. Many people affected die in their 20s and 30s from lung failure. However, with the continuous introduction of many new treatments, the life expectancy of a person with cystic fibrosis is increasing to ages as high as 40 or 50. Lung transplantation is often necessary as CF worsens. CF is caused by a mutation in a gene called the cystic fibrosis transmembrane conductance regulator (CFTR). The product of this gene is a chloride ion which is important in creating sweat, digestive juices, and mucus. Although most people without CF have two working copies (alleles) of the CFTR gene, only one is needed to prevent cystic fibrosis. CF develops when neither allele can produce a functional CFTR protein.

Scientists Use Pigs to Try to Beat Cystic Fibrosis

WASHINGTON (Reuters) - U.S. scientists have created pigs that appear to develop cystic fibrosis just as people do, a step they hope will accelerate efforts to tackle the disease.

Writing in the journal Science on Thursday, scientists at the University of Iowa and the University of Missouri said they created genetically engineered piglets with the same mutation that causes cystic fibrosis in people.

Studying how the disease unfolds in these pigs may provide insights into cystic fibrosis that thus far have eluded scientists and could point toward new treatments or maybe even a cure, said Dr. Michael Welsh of the University of Iowa.

People get CF when they inherit two mutated copies of a gene called CFTR, which was pinpointed as the cause in 1989. The disease causes mucus to accumulate and clog some of the organs in the body, especially the lungs and pancreas.

The Cystic Fibrosis Foundation, which helped fund the study, said about 70,000 people worldwide, including 30,000 people in the United States, have CF. People with the disease can expect to live to about age 37.

Scientists create animal "models" of a disease in order to perform experiments that would not be possible with people. Mice with the genetic abnormality that causes cystic fibrosis have been developed, but the disease presents itself very differently in these rodents than in people.

"Unfortunately, the mice leave something to be desired," Welsh, who helped lead the study, said in a telephone interview.

"They don't get the pancreatic disease like people with CF get. They don't get the lung disease like people with CF get. They don't get the intestinal disease like people with CF get. There's been many questions that can't be answered," he added.

"The onset of these problems is difficult to track down in humans because sometimes they happen before birth or sometimes they happen silently," added Christopher Penland of the foundation.

This is the latest example of pigs used for human medical needs. For example, cardiac patients can get pig heart valves.

The scientists developed pigs with cystic fibrosis because their lungs have many characteristics of human lungs.

"Right now, if you want to do experiments to find treatments or therapies for the lung disease that is fatal for people with CF, you would have to experiment on kids that have CF," Randy Prather of the University of Missouri added.

The disease in pigs closely mimicked the initial stages of the disease seen in people. The scientists are waiting for them to develop lung disease typical of CF "so we can start experimenting in ways that have never been possible," Prather said in a statement.

U.S. Fission Nuclear Bomb Test - Grable

Fission Nuclear Bomb At Sea: Bikini Atolls

Fission Bomb "Ivy King" - www.pastfinder.de

Atomic bomb on Hiroshima and Nagasaki

Nuclear Fission

Nuclear fission is the process of splitting atoms often producing free neutrons and other smaller nuclei, which may eventually produce photons in the form of gamma rays. The sum of the masses of these neutrons is less than the original mass. This 'missing' mass has been converted into energy according to Einstein's equation. Fission of heavy elements is an exothermic, chain reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments.

Nuclear fission produces energy for nuclear power and to drive the explosion of nuclear weapons. Both uses are made possible because certain substances called nuclear fuels undergo fission when struck by free neutrons and in turn generate neutrons when they break apart. This makes possible a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.

Nuclear fission differs from other forms of radioactive decay in that it can be harnessed and controlled via a chain reaction: free neutrons released by each fission can trigger yet more atom splits, which in turn release more neutrons which cause even more fissions. Chemical isotopes that can sustain a fission chain reaction are called nuclear fuels, and are said to be fissile. The most common nuclear fuels are Uranium-235 with an atomic mass of 235 and of use in nuclear reactors, and plutonium-239 with an atomic mass of 239.

In one of the most remarkable phenomena in nature, a slow neutron can be captured by a uranium-235 nucleus, rendering it unstable toward nuclear fission. A fast neutron will not be captured, so neutrons must be slowed down by moderation to increase their capture probability in fission reactors. A single fision event can yield over 200 million times the energy of the neutron which triggered it.

A fission bomb is a fission reactor designed to liberate as much energy as possible as rapidly as possible, before the released energy causes the reactor to explode, and the chain reaction to stop. Development of nuclear weapons was the motivation behind early research into nuclear fission: the Manhattan Project of the U.S. military during World War II carried out most of the early scientific work on fission chain reactions, culminating in the Trinity, Little Boy, and Fat Man bombs that were exploded over test sites, the cities Hiroshima, and Nagasaki, Japan in August 1945.

Plutonium

Plutonium is a rare radioactive, metallic chemical element with symbol Pu and an atomic number 94. The most significant isotope of plutonium is 239Pu, with a half-life of 24,100 years. This isotope is fissile and is used in most modern nuclear weapons. Plutonium-239 can be synthesized from natural uranium. But the most stable isotope is 244Pu, with a half-life of approximately 80 million years, long enough to be found in extremely small quantities in nature, making 244Pu the most nucleon-rich atom that naturally occurs in the Earth's crust, albeit in small traces.

Plutonium was the second transuranium element of the actinide series to be discovered. By far of greatest importance is the isotope 239Pu, which has a half-life of more than 20000 years. One kilogram is equivalent to about 22 million kilowatt hours of heat energy. The complete detonation of a kilogram of plutonium produces an explosion equal to about 20000 tons of chemical explosive. The various nuclear applications of plutonium are well known. The isotope 233Pu was used in the American Apollo lunar missions to power seismic and other equipment on the lunar surface. Plutonium contamination is an emotive environmental problem.

Plutonium is silvery in pure form, but has a yellow tarnish when oxidized. It possesses a low-symmetry structure, causing it to become progressively more brittle over time. The isotope 239Pu is a key fissile component in nuclear weapons, due to its ease of fissioning and availability. The critical mass for an unreflected sphere of plutonium is 16 kg, but through the use of a neutron-reflecting tamper the pit of plutonium in a fission bomb is reduced to 10 kg, which is a sphere with a diameter of 10 cm. The Manhattan Project "Fat Man" type plutonium bombs, using explosive compression of Pu to significantly higher densities than normal, were able to function with plutonium cores of only 6.2 kg. Complete detonation may be achieved through the use of an additional neutron source. The Fat Man bomb had an explosive yield of 21 kilotons.

The isotope plutonium-238 (238Pu) has a half-life of 88 years and emits a large amount of thermal energy as it decays. Being an alpha emitter, it combines high energy radiation with low penetration (thereby requiring minimal shielding). These characteristics make it well suited for electrical power generation for devices which must function without direct maintenance for timescales approximating a human lifetime. 238Pu has been used successfully to power artificial heart pacemakers, to reduce the risk of repeated surgery. It has been largely replaced by lithium-based primary cells, but as of 2003 there were somewhere between 50 and 100 plutonium-powered pacemakers still implanted and functioning in living patients.

Uranium

Uranium is a silver-gray metallic chemical element that has the symbol U and atomic number 92. It has 92 protons and 92 electrons, 6 of them valence electrons. It can have between 141 and 146 neutrons, with 146 and 143 in its most common isotopes. Uranium has the highest atomic weight of the naturally occurring elements, 238.02891. It occurs naturally in low concentrations in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite, carnotite, autunite, uranophane, and tobernite. It is also found in phosphate rock, lignite, monazite sands, and can be recovered commercially from these sources.

In nature, uranium atoms exist as uranium-238 (99.284%), uranium-235 (0.711%), and a very small amount of uranium-234 (0.0058%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth. Contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 has the distinction of being the only naturally occurring fissile isotope. Uranium-238 is both fissionable by fast neutrons, capable of being transmuted to fissile plutonium-239 in a nuclear reactor.

While uranium-238 has a small probability to fission when bombarded with fast neutrons, the much higher probability of uranium-235 to fission when bombarded with slow neutrons generates the heat in nuclear reactors used as a source of power, and provides the fissile material for nuclear weapons. Both uses rely on the ability of uranium to produce a sustained nuclear chain reaction. Depleted uranium (uranium-238) is used in kinetic energy penetrators in armor-piercing weapons.

The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the planet Uranus. Eugene-Melchior Peligot was the first person to isolate the metal, and its radioactive properties were uncovered in 1896 by Antoine Becquerel. Research by Enrico Fermi and others starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war.

Uranium:

• Atomic Number: 92


• Atomic Symbol: U


• Atomic Weight: 238.029


• Atomic Radius: 138.5 pm


• Melting Point: 1135 C


• Electron Configuration: [Rn]7s25f36d1
  

Radioactivity

Radioactivity is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles. The radioactive phenomenon is observed in the heavy elements such as uranium, and unstable isotopes, like carbon-14. As a spontaneous disintegration of atomic nuclei, nucleus emits ­Alpha particles and ßeta particles, or electromagnetic rays during this process. Alpha decay occurs when the nucleus spontaneously ejects an Alpha particle. An Alpha particle is really 2 protons and 2 neutrons. So when an atom undergoes decay, its atomic number decreases by 2 and its atomic mass decreases by 4. Alpha particles do not penetrate much material, for they can be stopped by paper.

There are two types of ß decay; ß+ and ß- decay. An excess of neutrons in an atom's nucleus will make it unstable, and a neutron is converted into a proton to change this ratio. During this process, a ß particle is released, and it has the same mass and charge as an electron. The resulting atom and the ß particle have a total mass which is less than the mass of the original atom, and one would think that the ß particles should have the energy equivalent to the mass lost (E = mc2). But ß particles aren't mono-energetic, and have a broad energy spectrum from zero to the maximum energy predicted.

Radioactivity was first discovered in 1896 by the French scientist Henri Becquerel, while working on phosphorescent materials. These materials glow in the dark after exposure to light, and he thought that the glow produced in cathode ray tubes by X-rays might be connected with phosphorescence. He wrapped a photographic plate in black paper and placed various phosphorescent minerals on it. All results were negative until he used uranium salts. The result with these compounds was a deep blackening of the plate. These radiations were called Becquerel Rays.

Radioactivity in small doses is a useful process that can be harnessed by man. For example, nuclear reactors exploit radioactivity to generate heat. Phosphorescent materials sometimes include small quantities of radioactive atoms. During pharmaceutical testing, drugs are sometimes laced with radioactive atoms so that they can be more easily traced as they move throughout the body. In large doses, radioactivity is extremely dangerous. In the Ukraine, a nuclear reactor meltdown incident that occurred during the Cold War era continues to have deleterious effects on the local population to this very day. Many weapons have been designed and tested which use radioactivity to kill people in large numbers.

Meteorology

Meteorology is the scientific study of the atmosphere as it focuses on weather processes and forecasting. Meteorological phenomena are observable weather events which are explained by the science of meteorology. Those events are bound by the variables that exist in Earth's atmosphere. They are temperature, pressure, water vapor, and the gradients and interactions of each variable, and how they change in time. The majority of Earth's observed weather is located in the troposphere. Interactions between Earth's atmosphere and the oceans are part of coupled ocean-atmosphere studies. Meteorology has application in many diverse fields such as the military, energy production, transport, agriculture and construction.

In the study of the atmosphere, meteorology can be divided into distinct areas of emphasis depending on the temporal scope and spatial scope of interest.

Boundary Layer Meteorology: Boundary layer meteorology is the study of processes in the air layer directly above Earth's surface, known as the atmospheric boundary layer (ABL) or peplosphere. The effects of the surface – heating, cooling, and friction – cause turbulent mixing within the air layer. Significant fluxes of heat, matter, or momentum on time scales of less than a day are advected by turbulent motions. Boundary layer meteorology includes the study of all types of surface-atmosphere boundary, including ocean, lake, urban land and non-urban land.

Mesoscale Meteorology: Mesoscale meteorology is the study of atmospheric phenomena that has horizontal scales ranging from microscale limits to synoptic scale limits and a vertical scale that starts at the Earth's surface and includes the atmospheric boundary layer, troposphere, tropopause, and the lower section of the stratosphere. Mesoscale timescales last from less than a day to the lifetime of the event, which in some cases can be weeks. The events typically of interest are thunderstorms, squall lines, fronts, precipitation bands in tropical and extratropical cyclones, and topographically generated weather systems such as mountain waves and sea and land breezes.

Synoptic Scale Meteorology: It is generally large area dynamics referred to in horizontal coordinates and with respect to time. The phenomena typically described by synoptic meteorology include events like extratropical cyclones, baroclinic troughs and ridges, frontal zones, and to some extent jets. All of these are typically given on weather maps for a specific time. The minimum horizontal scale of synoptic phenomena are limited to the spacing between surface observation stations.

Global Scale Meteorology: It is the study of weather patterns related to the transport of heat from the tropics to the poles. Also, very large scale oscillations are of importance. Those oscillations have time periods typically longer than a full annual seasonal cycle, such as ENSO, PDO, MJO, etc. Global scale pushes the thresholds of the perception of meteorology into climatology. The traditional definition of climate is pushed in to larger timescales with the further understanding of how the global oscillations cause both climate and weather disturbances in the synoptic and mesoscale timescales.

Dynamic Meteorology: Dynamic meteorology generally focuses on the physics of the atmosphere. The idea of air parcel is used to define the smallest element of the atmosphere, while ignoring the discrete molecular and chemical nature of the atmosphere. An air parcel is defined as a point in the fluid continuum of the atmosphere. The fundamental laws of fluid dynamics, thermodynamics, and motion are used to study the atmosphere. The physical quantities that characterize the state of the atmosphere are temperature, density, pressure, etc. These variables have unique values in the continuum.

Epilepsy

Epilepsy is a chronic neurological disorder that is characterized by recurrent unprovoked seizures. These seizures are transient signs of abnormal neuronal activity in the brain manifested by clouding of consciousness. Clusters of nerve cells, or neurons, in the brain sometimes signal abnormally. In epilepsy, the normal pattern of neuronal activity becomes disturbed, causing strange sensations, convulsions, muscle spasms, and loss of consciousness.

About 50 million people worldwide have epilepsy at any one time. Epilepsy is usually controlled, but not cured, with medication, although surgery may be considered in difficult cases. However, over 30% of people with epilepsy do not have seizure control even with the best available medications. Not all epilepsy syndromes are lifelong – some forms are confined to particular stages of childhood. Epilepsy should not be understood as a single disorder, but rather as a group of syndromes with vastly divergent symptoms but all involving episodic abnormal electrical activity in the brain.

Epilepsy is a disorder with many possible causes. Anything that disturbs the normal pattern of neuron activity - from illness to brain damage to abnormal brain development - can lead to seizures. Epilepsy may develop because of an abnormality in brain wiring, an imbalance of nerve signaling chemicals called neurotransmitters, or some combination of these factors. Having a seizure does not necessarily mean that a person has epilepsy. Only when a person has had two or more seizures is he or she considered to have epilepsy. EEGs and brain scans are common diagnostic test for epilepsy.

Treatment: Once epilepsy is diagnosed, it is important to begin treatment as soon as possible. For about 80 percent of those diagnosed with epilepsy, seizures can be controlled with modern medicines and surgical techniques. Some antiepiletic drugs can interfere with the effectiveness of oral contraceptives. In 1997, the FDA approved the vagus nerve stimulator for use in people with seizures that are not well-controlled by medication.

Prognosis: Most people with epilepsy lead outwardly normal lives. While epilepsy cannot currently be cured, for some people it does eventually go away. Most seizures do not cause brain damage. It is not uncommon for people with epilepsy, especially children, to develop behavioral and emotional problems, sometimes the consequence of embarrassment and frustration or bullying, teasing, or avoidance in school and other social setting. For many people with epilepsy, the risk of seizures restricts their independence (some states refuse drivers licenses to people with epilepsy) and recreational activities. People with epilepsy are at special risk for two life-threatening conditions: status epilepticus and sudden unexplained death.

Epilepsies are classified in five ways:

A) By their first cause (etiology).

B) By the observable manifestations of the seizures, known as semiology.

C) By the location in the brain where the seizures originate.

D) As a part of discrete, identifiable medical syndromes.

E) By the event that triggers the seizures, as in primary reading epilepsy.

Scientists are studying potential antiepileptic drugs with goal of enhancing treatment for epilepsy. Scientists continue to study how neurotransmitters interact with brain cells to control nerve firing and how non-neuronal cells in the brain contribute to seizures. One of the most-studied neurotransmitters is GABA, or gamma-aminobutyric acid. Researchers are working to identify genes that may influence epilepsy. This information may allow doctors to prevent epilepsy or to predict which treatments will be most beneficial. Doctors are now experimenting with several new types of therapies for epilepsy, including transplanting fetal pig neurons into the brains of patients to learn whether cell transplants can help control seizures, transplanting stem cells, and using a device that could predict seizures up to 3 minutes before they begin.

Frontal Lobe Epilepsy: Frontal lobe epilepsy is a type of seizure that often goes unnoticed by sufferers. Since the frontal lobe of the brain does not have a known function, seizures that occur within this area generally have mild symptoms. On the other hand, if the seizure spreads to other parts of the brain, the sufferer may experience involuntary body movements or twitches. Epilepsy is a disorder of the nervous system. Individuals who suffer from the condition may have experienced epileptic seizures since childhood, or developed the condition later in life. Because frontal lobe epilepsy can consist of seizures lasting only a few seconds, some sufferers disregard the incidents. During those few seconds, a person may feel slightly dizzy or lightheaded. However, unless a brain scan is preformed, these persons may never be aware of their condition.

Principles of Geology

There are a number of important principles in geology. Many of these involve the ability to provide the relative ages of strata or the manner in which they were formed.

• The principle of intrusive relationships concerns crosscutting intrusions. In geology, when an igneous intrusion cuts across a formation of sedimentary rock, it can be determined that the igneous intrusion is younger than the sedimentary rock. There are a number of different types of intrusions, including stocks, laccoliths, batholiths, sills and dikes.
• The principle of cross-cutting relationships pertains to the formation of faults and the age of the sequences through which they cut. Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault. Finding the key bed in these situations may help determine whether the fault is a normal fault or a thrust fault.
• The principle of inclusions and components states that, with sedimentary rocks, if inclusions are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar situation with igneous rocks occurs when xenoliths are found. These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in the matrix. As a result, xenoliths are older than the rock which contains them.
• The principle of uniformitarianism states that the geologic processes observed in operation that modify the Earth's crust at present have worked in much the same way over geologic time. A fundamental principle of geology advanced by the 18th century Scottish physician and geologist James Hutton, is that "the present is the key to the past." In Hutton's words: "the past history of our globe must be explained by what can be seen to be happening now."
• The principle of original horizontality states that the deposition of sediments occurs as essentially horizontal beds. Observation of modern marine and non-marine sediments in a wide variety of environments supports this generalization. Although cross-bedding is inclined, the overall orientation of cross-bedded units is horizontal.
• The principle of superposition states that a sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it. Logically a younger layer cannot slip beneath a layer previously deposited. This principle allows sedimentary layers to be viewed as a form of vertical time line, a partial or complete record of the time elapsed from deposition of the lowest layer to deposition of the highest bed.
• The principle of faunal succession is based on the appearance of fossils in sedimentary rocks. As organisms exist at the same time period throughout the world, their presence may be used to provide a relative age of the formations in which they are found. Based on principles laid out by William Smith almost a hundred years before the publication of Charles Darwin's theory of evolution, the principles of succession were developed independently of evolutionary thought. The principle becomes quite complex, however, given the uncertainties of fossilization, the localization of fossil types due to lateral changes in habitat, and that not all fossils may be found globally at the same time.

Geology

Geology is the science that deals with the history of the Earth and the solid and molten matter that constitutes it. Geology studies the composition, structure, physical properties and the processes that shape Earth's components. Geology has established the age of the Earth at about 5,000 billion years. The word "geology" was first used by Jean-Andre Deluc in the year 1778 and introduced as a fixed term by Horace-Benedict de Saussure in the year 1779.

Defibrillator Implants: Hard Choice for Patients

The implanted defibrillator, a device that can automatically shock an erratically beating heart back to a normal rhythm, has been proved to save lives. Hence its nickname: an emergency room in the chest. Major medical groups have recommended that more patients receive the devices.

But in the last two years the number of patients receiving defibrillators has actually declined, as more doctors and patients decide the risks and uncertainties the devices pose may outweigh their potential benefits.

This trend — the first decline since implanted defibrillators were introduced in 1985 — has spotlighted a shortcoming that health experts have struggled with for years. Simply put, there is no adequate tool or test to predict which of the heart patients who might seem good candidates to get the expensive devices are the ones most likely to ever need their life-saving shock. Defibrillators have undoubtedly saved the lives of tens of thousands of Americans. That is why insurers still typically pay for the devices and the surgical procedure to implant them, which can top $50,000 for each patient.

What makes many doctors and patients increasingly wary, though, is a string of highly publicized recalls in recent years, along with mounting evidence suggesting that a vast majority of people who get a defibrillator never need it.
Industry estimates and medical studies indicate that defibrillators have saved the lives of 10 percent of the more than 600,000 people in this country who have received them, at most. While survivors would no doubt take those odds, 9 of 10 people who get defibrillators receive no medical benefit. One big long-term medical study indicated the odds of a defibrillator saving a patient’s life might be even slimmer — about 1 in 14, over the five-year period studied.

The problem that defibrillators pose is in some ways singular among medical technologies. For devices like artificial knees, which improve lives but do not save them, few people would settle for only a 1 in 10 chance of success. For a potentially life-saving cancer drug, a patient might grasp at even much slimmer odds. Where defibrillators differ is that they are only a powerful standby — ready to intervene if necessary, but unlikely ever to be called into service.

If defibrillators were simply $50,000 life insurance policies, the relatively low rate of payoff might not matter much. But the long-shot statistics are significant to people who must weigh the risks of infection and malfunction after they have an electronic device anchored inside their hearts and its wires threaded through their arteries.

The slim odds also have large implications for the United States health care bill, adding billions of dollars annually to Medicare spending and to insurance payments. Dr. Larry A. Chinitz, director of the Heart Rhythm Center at New York University’s Langone Medical Center, said, “The answer isn’t just to keep implanting everybody” who fits the current guidelines.

More doctors are now thinking twice. From a peak of 160,000 new patients in 2005, the number has fallen to less than 140,000 last year, according to Lawrence H. Biegelsen, an analyst at Wachovia Capital Markets. He predicts this year’s total will end up even lower. For the manufacturers, the numbers translate to a decline in defibrillator sales to $3.94 billion in this country last year, down from $4.29 billion in 2005, Mr. Biegelsen said.

Only overseas, where defibrillators have been slower to catch on, has the number of new implants continued to rise, hitting a new sales high of $1.93 billion last year.

Many patients, of course, are grateful for their defibrillators. “It’s saved me at least four times, including two when I passed out completely,” Matthew M. Murray, a 55-year-old former engineer in Riverbank, Calif., said of his implant.

And some experts worry that the pendulum may have swung too far away from defibrillators — putting countless lives at risk among people with the heart abnormalities and ailments most likely to cause cardiac arrest. At least several hundred thousand people in this country have such conditions, and some estimates place the figure at more than a million.

Meltronic, the leading maker of defibrillators, contends that each day 500 deaths are caused by sudden cardiac arrests among people who meet the current medical guidelines for the devices but do not have them. The NBC journalist Tim Russert, who died earlier this year, reportedly suffered a heart attack after an artery was blocked. While Mr. Russert had a history of heart disease, his condition was not one for which a defibrillator would have been prescribed.

Dr. Eric N. Prystowsky, a nationally renowned heart rhythm specialist in Indianapolis, said every doctor in his field was haunted by individual cases, like that of a Purdue University graduate student who was referred to Dr. Prystowsky for a defibrillator. The student had an abnormally thick heart muscle, a known risk for sudden cardiac arrest.

“He kept putting it off,” Dr. Prystowsky said of the decision to get a defibrillator. “Six weeks later, his fiancée called to say he had been found dead in bed.”

Cases like that may be inevitable as long as doctors cannot give patients more certainty about whether a defibrillator will actually help them.

Better clues could be submerged in the medical records of the people who have gotten defibrillators over the decades. Three years ago, Medicare ordered the creation of a nationwide registry, or database, for implanted defibrillators. Overseen by two leading professional groups, the American College of Cardiology and the Heart Rhythm Society, the registry has amassed about 270,000 records from 1,500 hospitals. But the data mining has only recently begun, and results are not expected before 2010 at the earliest.

Astrophysics

Astrophysics is the branch of astronomy which deals with the physical properties of celestial bodies and with the interaction between matter and radiation in the interior of celestial bodies and in interstellar space. However, since most modern astronomical research deals with subjects related to physics, modern astronomy could actually be called astrophysics.

Astronomy

Astronomy is the science of celestial bodies, such as planets, stars, and comets, and phenomena which originate outside the earth's atmosphere. Astronomy is one of the oldest sciences. At the beginning, in ancient times, astronomers performed methodical, naked-eyed observations of the night sky. But the invention of the telescope was required before astronomy was able to develop into a modern science. Amateur astronomers have contributed to many important astronomical discoveries, as astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena.

In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye. In some locations, such as Stonehenge, early cultures assembled massive artifacts that likely had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops, as well as in understanding the length of the year. Before tools such as the telescope were invented early study of the stars had to be conducted from the only vantage points available, namely tall buildings, trees and high ground using the bare eye.

Prior to the application of the telescope, a few notable astronomical discoveries were made. For example, the obliquity of the ecliptic was estimated as early as 1000 BC by the Chinese. The Chaldeans discovered that lunar eclipses recurred in a repeating cycle known as a saros. In the 2nd century BC, the size and distance of the Moon were estimated by Hipparchus.

Particle Collider Test Successful

GENEVA) — The world's largest particle collider successfully completed its first major test by firing a beam of protons all the way around a 17-mile (27-kilometer) tunnel Wednesday in what scientists hope is the next great step to understanding the makeup of the universe.

After a series of trial runs, two white dots flashed on a computer screen indicating that the protons had traveled the full length of the US$3.8 billion Large Hadron Collider.

There it is," project leader Lyn Evans said when the beam completed its lap.

The startup was eagerly awaited by 9,000 physicists around the world who now have much greater power than ever before to smash the components of atoms together in attempts to see how they are made.

"Well done everybody," said Robert Aymar, director-general of the European Organization for Nuclear Research, said after the protons were fired into the accelerator below the Swiss-French border at 9:32 a.m. (0732 GMT).

The organization, known by its French acronym CERN, fired the protons — a type of subatomic particle — around the tunnel in stages, several kilometers (miles) at a time.

Now that the beam has been successfully tested in clockwise direction, CERN plans to send it counterclockwise. Eventually the two beams will be fired in opposite directions with the aim of smashing together protons to see how they are made.

The startup comes over the objections of some skeptics who fear the collisions of protons could eventually imperil the earth. The skeptics theorized that a byproduct of the collisions could be micro black holes, subatomic versions of collapsed stars whose gravity is so strong they can suck in planets and other stars.

"It's nonsense," said James Gillies, chief spokesman for CERN, before Wednesday's start.

CERN is backed by leading scientists like Britain's Stephen Hawking in dismissing the fears and declaring the experiments to be absolutely safe.
Gillies told the AP that the most dangerous thing that could happen would be if a beam at full power were to go out of control, and that would only damage the accelerator itself and burrow into the rock around the tunnel. But full power is probably a year away.

"On Wednesday we start small," said Gillies. "A really good result would be to have the other beam going around, too, because once you've got a beam around once in both directions you know that there is no show-stopper."

The LHC, as the collider is known, will take scientists to within a split second of a laboratory recreation of the big bang, which they theorize was the massive explosion that created the universe.

The project organized by the 20 European member nations of CERN has attracted researchers from 80 nations. Some 1,200 are from the United States, an observer country which contributed $531 million. Japan, another observer, also is a major contributor.

The collider is designed to push the proton beam close to the speed of light, whizzing 11,000 times a second around the tunnel. Smaller colliders have been used for decades to study the makeup of the atom. Less than 100 years ago scientists thought protons and neutrons were the smallest components of an atom's nucleus, but in stages since then experiments have shown they were made of still smaller quarks and gluons and that there were other forces and particles.

The CERN experiments could reveal more about "dark matter," antimatter and possibly hidden dimensions of space and time. It could also find evidence of the hypothetical particle — the Higgs boson — believed to give mass to all other particles, and thus to matter that makes up the universe.

The Large Hadron Collider

The Large Hadron Collider is the world's largest, high energy particle accelerator and is intended to collide opposing beams of protons charged with approximately 7 TeVs of energy. Straddling the border of Switzerland and France, this 17-mile long, underground complex may also produce "unparticles", a possible source for dark matter. With this particle accelarator the energy may be so focused that even the fabric of space-time may be pulled apart to create a wormhole, not to a different place, but a different time. Prof Irina Aref'eva and Dr Igor Volovich, mathematical physicists at the Steklov Mathematical Institute in Moscow believe the energies generated by the subatomic collisions in the LHC may be powerful enough to rip space-time itself, spawning wormholes. A wormhole not only has the ability to take a shortcut between two positions in space, it can also take a shortcut between two positions in time.

The Large Hadron Collider is used by physicists to study the smallest known particles – the fundamental building blocks of all things. It will revolutionize our understanding, from the minuscule world deep within atoms to the vastness of the Universe. Its main purpose is to explore the validity and limitations of the Standard Model, the current theoretical picture for particle physics. It is theorized the collider will produce the elusive Higgs boson, the observation of which could confirm the predictions and missing links in the Standard Model of physics and could explain how other elementary particles acquire properties such as mass.

Two beams of subatomic particles called hadrons – either protons or lead ions – will travel in opposite directions inside the circular accelerator, gaining energy with every lap. Physicists use the Large Hadron Collider to recreate the conditions just after the Big Bang, by colliding the two beams head-on at very high energy. Teams of physicists from around the world will analyze the particles created in the collisions using special detectors in a number of experiments dedicated to the LHC.

Medicine

Medicine is the science and art dealing with the maintenance of health, and the prevention or cure of disease. Contemporary medicine applies biomedical research and technology to diagnose and treat injury and disease, through medication, surgery, or some other form of therapy. Although many of their theories were discredited through the centuries, the founder of medicine were the Greek philosophers and physicians Hippocrates, Galen and Avicenna.

Medicine took advantage of the development of other sciences such as physics whose scientists invented optical instruments such as the microscope, and later the x-ray machine. The modern era began with the vaccines discovered by Edward Jenner and Louis Pasteur against smallpox and hydrophobia respectively. Later in 1880, Robert Koch discovered the infectious diseases were transmitted by bacteria.

Anthropology

Anthropology: from Gk anthropo, man; logy, study. Anthropology is the study of human beings in relation to origin, culture, and environmental and social relations. Anthropology is divided into three branches: physical anthropology, linguistics, and cultural anthropology.

Physical anthropology: it studies anatomy, biological evolution, primatology, genetic inheritance, and the fossil record of human evolution.

Linguistics: it is the scientific study of language and historic relationship among them. Linguistics concerns itself with describing and explaining the nature of human language.

Cultural anthropology: it studies human culture in a historic and comparative perspective. There is a subfield that concentrates on myth, music, and folklore to study human geography and human passage in time.

Chemistry

Chemistry is the science which deals with the composition, melecular and atomic structure, and properties of substances and with the transformation that they undergo. Modern chemistry evolved out of alchemy, which had been practiced for several centuries in various parts of the world, particularly during the Middle Ages, when scholars in those days thought that they could transform cheaper metals into gold. Chemistry is often called the central science because it connects the other natural sciences, such as astronomy, physics, biology, and geology.

The influences of philosophers such as Sir Francis Bacon (1561-1626) and Rene Descartes (1596-1650), who demanded more rigor in mathematics and in removing bias from scientific observations, led to a scientific revolution. In chemistry, this began with Robert Boyle (1627-1691), who came up with an equations known as the Boyle's Law about the characteristics of gaseous state. Chemistry indeed came of age when Antoine Lavoisier (1743-1794), developed the theory of Conservation of mass in 1783, and the development of the Atomic Theory by John Dalton around 1800. The Law of Conservation of Mass resulted in the reformulation of chemistry based on this law and the oxygen theory of combustion, which was largely based on the work of Lavoisier.

Physics

Physics is the science concerned with the study of matter and energy and their interactions in the fields of mechanics, acoustics, heat, electricity, magnetism, radiation, atomic structure, and nuclear phenomena. Physics is an experimental science, which creates theories that are tested, with the scientific analysis of nature and the universe to understand how it works.

Although the modern discipline of physics emerged in the 17th century with the works and theories of Galileo Galilei, Isaac Newton, Rene Descartes, and other natural philosophers, theories about how the universe works were put forward by Greek philosophers in Ancient Times. Eudoxus of Cynidus (400-347 B.C.), who was an associate of Plato, created a very complex astronomy in terms of his description of the movement of heavenly bodies.