Solar Eclipse

A solar eclipse occurs when the moon passes between the Sun and the Earth so that the Sun is fully or partially covered. This can only happen during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. At least two and up to five solar eclipses can occur each year on Earth, with between zero and two of them being total eclipses.Total solar eclipses are nevertheless rare at any location because during each eclipse totality exists only along a narrow corridor in the relatively tiny area of the Moon's umbra.

TB

In the past, tuberculosis has been called consumption, because it seemed to consume people from within, with a bloody cough, fever, pallor, and long relentless wasting. Other names included phthisis (Greek for consumption) and phthisis pulmonalis; scrofula (in adults), affecting the lymphatic system and resulting in swollen neck glands; tabes mesenterica, TB of the abdomen and lupus vulgaris, TB of the skin; wasting disease; white plague, because sufferers appear markedly pale; king's evil, because it was believed that a king's touch would heal scrofula; and Pott's disease, or gibbus of the spine and joints.

Dr. Robert Koch discovered the tuberculosis bacillus.

Miliary tuberculosis—now commonly known as disseminated TB—occurs when the infection invades the circulatory system, resulting in lesions which have the appearance of milletseeds on X-ray.^[96][98] TB is also called Koch's disease, after the scientist Robert Koch

Triple point

From Wikipedia, the free encyclopedia

In thermodynamics, the triple point of a substance is the temperature and pressure at which three phases (for example, gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.^[1] For example, the triple point of mercury occurs at a temperature of −38.8344 °C and a pressure of 0.2 mPa.

In addition to the triple point between solid, liquid, and gas, there can be triple points involving more than one solid phase, for substances with multiple polymorphs. Helium-4 is a special case that presents a triple point involving two different fluid phases (see lambda point). In general, for a system with p possible phases, there are triple points.

Transuranic Elements

Any element lying beyond uranium in the periodic table, i.e. any element of atomic number greater than 92. Except for the plutonium isotopes Pu-244 (half-life about 80 million years) and Pu-239 (continuous reformation in rock containing uranium by neutron capture in U-238 by neutrons from the spontaneous fission of U-238) detected in very small quantities, all transuranic elements must be produced artificially by suitable nuclear reactions. All are radioactive.

Table of transuranic elements
element name	symbol	atomic no.
neptunium	Np	93
plutonium	Pu	94
americium	Am	95
curium	Cm	96
berkelium	Bk	97
californium	Cf	98
einsteinium	Es	99
fermium	Fm	100
mendelevium	Md	101
nobelium	No	102
lawrencium	Lw	103
rutherfordium	Rf	104
dubnium	Db	105
seaborgium	Sb	106
bohrium	Bh	107
hassium	Hs	108
meitnerium	Mt	109
darmstadtium	Ds	110
roentgenium	Rg	111
not yet named	-	112
not yet named	-	114
not yet named	-	115

A time zone is a region of the earth that has uniform standard time, usually referred to as the local time. By convention, time zones compute their local time as an offset from UTC (see also Greenwich Mean Time). Local time is UTC plus the current time zone offset for the considered location.

Standard time zones (Winter Time zones) can be defined by geometrically subdividing the Earth's spheroid into 24 lunes (wedge-shaped sections), bordered by meridians each 15° of longitude apart. The local time in neighboring zones would differ by one hour. However, political boundaries, geographical practicalities, and convenience of inhabitants can result in irregularly-shaped zones. Moreover, in a few regions, half-hour or quarter-hour differences are in effect.Time zones are divided into standard and daylight saving (or summer). Daylight saving time zones (or summer time zones) include an offset (typically +1) for daylight saving time.

Before the adoption of time zones, people used local solar time. Originally this was apparent or true solar time, as shown by a sundial, and later it became mean solar time, as kept by most mechanical clocks. Mean solar time has days of equal length, but the difference between mean and apparent solar time, called the equation of time, averages to zero over a year.

The use of local solar time became increasingly awkward as railways and telecommunications improved, because clocks differed between places by an amount corresponding to the difference in their geographical longitude, which was usually not a convenient number. This problem could be solved by synchronizing the clocks in all localities, although in many places the local time would then differ markedly from the solar time to which people were accustomed. Time zones are thus a compromise, relaxing the complex geographic dependence while still allowing local time to approximate the mean solar time. There has been a general trend to push the boundaries of time zones further west of their designated meridians in order to create a permanent daylight saving time effect. The increase in worldwide communication has further increased the need for interacting parties to communicate mutually comprehensible time references to one another.

List of Carnivorous Plants

Source--http://www.gardenguides.com/67713-list-carnivorous-plants.html

List of Carnivorous Plants

The world of carnivorous plants is far stranger and more extensive than the commonly known examples of the Venus flytrap and pitcher plant. The criteria for considering whether a plant is carnivorous include its adaptations to capture prey and the presence of digestive enzymes, helper bacteria, or another way of benefiting from the nutrients in the prey that they capture.

Aldrovanda

This plant is also known as the "waterwheel plant" and is similar to an underwater Venus flytrap. Its leaves are arranged in a wheel shape with the leafy traps on the end of its arms.

Cephalotus

The Cephalotis follicularis is also known as the Albany pitcher plant. It was named after the city of Albany, Australia in southwestern Australia and primarily grows in that area. It is pitcher shaped and covered with bristles.

Darlingtonia

This plant, also known as the cobra lily, grows along the Pacific coast in patches from Oregon to California. It relies on bacteria and animals such as flying midges and slime mites to digest its prey.

Dionaea

The Dionaea muscipula, better known as the Venus flytrap, is the most famous of the carnivorous plants. Its native range is the lowlands of North Carolina. Their habitat is threatened, but they can be seen at Carolina Beach State Park near Wilmington, North Carolina.

Drosera

Droseras are also known as sundews. There are over 180 known species of drosera growing on every continent except for Antartica. Insects that land on their leaves are caught by adhesives and digested by enzymes. The leaves do move, like those of Venus flytraps, but the motion is very slow.

Drosophyllum

Drosophyllum, or the Dewy pine, is quite large for a carnivorous plant. Its individual leaves are over a foot tall and the entire plant can be up to two feet tall. It grows in arid regions along the Portuguese coast.

Genlisea

Genlisea are also known as corkscrew plants. They grow in wet habitats and their traps are located underwater. The trap structure is formed by curved hairs which only allow their prey to progress in one direction -- until it is too late.

Heliamphora

This genus is a type of pitcher plants that grown in the South American Highlands near the borders of Brazil, Venezuela and Guyana.

Nepenthes

Nepenthes are also known as tropical pitcher plants. Although they are most definitely carnivorous, there are over 150 species of animals that are known to go inside their pitchers without becoming prey. These animals range in size from mosquito larvae to frogs.

Pinguicula

These carnivorous plants are commonly known as butterworts. They have pretty flowers that rise far above their sticky leaves so that they do not consume their own pollinators.

Sarracenia

Sarracenia is also known as North American pitcher plants and range is primarily in the southeastern U.S. Their pitchers are narrow with slick sides and bottoms filled with digestive fluids and creatures such as mosquitoes, midges and flesh flies.

Utricularia

This genus contains over 220 species. Their common name is bladderwort and this gives a clue as to the operation of their traps. Small bladders pump out water from an interior chamber, which lowers the water pressure. Prey are sucked in and slowly digested.

Heart

Source--http://www.peteducation.com/article.cfm?c=17+1848&aid=2951

Throughout history, people have believed the heart plays a vital role in the body. The ancients supposed it was the seat of the spirit, the center of happiness, and in control of both the emotions and the intellect. Even today, we place the heart at the root of our emotions when we speak of being heartbroken or brave at heart. It is true that the heart plays an essential, life-giving role in an animal's body, but the mystery of what function it actually performs has been solved. The heart is the pump that drives the cardiovascular system.

Function of the Cardiovascular System

By circulating blood throughout the body, the cardiovascular system functions to supply the tissues with oxygen and nutrients, while removing carbon dioxide and other metabolic wastes. As oxygen-rich blood from the heart flows to the tissues of the body, oxygen and other chemicals move out of the blood and into the fluid surrounding the cells of the body's tissues. Waste products and carbon dioxide move into the blood to be carried away. As blood circulates through organs such as the liver and kidneys some of these waste products are removed. Blood then returns to the lungs (or gills, in the case of fish), receives a fresh dose of oxygen and gives off carbon dioxide. Then the cycle repeats itself. This process of circulation is necessary for continued life of the cells, tissues, and ultimately the whole organism. Up and down the evolutionary ladder, there are different forms of cardiovascular systems with different levels of efficiency, but they all perform this same basic function.

Mammalian Anatomy and Physiology

The cardiovascular systems of mammals, birds, amphibians, reptiles, and fish are all slightly different. The following is an overview of the main components of the mammalian system – the heart and blood vessels. A discussion of the other systems will follow.

Heart

The heart is composed of cardiac muscle that differs slightly from the skeletal and smooth muscle found elsewhere in the body. This special type of muscle adjusts the rate of muscular contraction, allowing the heart to maintain a regular pumping rhythm. The main parts of the heart are the chambers, the valves, and the electrical nodes.

Heart Chambers: There are two different types of heart chambers. The first is the atrium (plural is atria), which receives blood returning to the heart through the veins. The right atrium pumps blood to the right ventricle, and the left atrium pumps blood into the left ventricle. This blood is then pumped from the atrium into the second chamber called the ventricle. The ventricles are much larger than the atria and their thick, muscular walls are used to forcefully pump the blood from the heart to the body and lungs (or gills). See illustration below.

Valves: The valves found within the heart are situated between the atria and ventricles, and also between the ventricles and major arteries. These valves are opened and closed by pressure changes within the chambers, and act as a barrier to prevent the backflow of blood. The characteristic "lub-dub, lub-dub" heart sounds heard through a stethoscope are the result of vibrations caused by the closing of the respective valves.

Electrical Nodes: There are two different electrical nodes, or groups of specialized cells, located in the cardiac tissue. The first is the sinoatrial (SA) node, commonly called the pacemaker. The pacemaker is embedded in the wall of the right atrium. This small patch of tissue experiences rhythmic excitation and the impulse rapidly spreads throughout the atria, causing a muscular contraction and the pumping of blood from the atria to the ventricles. The other node, the atrioventricular (AV) node, relays the impulse of the SA node to the ventricles. It delays the impulse to prevent the ventricles from contracting at the same time as the atria, thus giving them time to fill with blood. The cycle of contraction of the heart muscle is called a heartbeat, the rate of which varies greatly between organisms. The following table gives the average heart rates of some common mammals.

Heart Rates Comparison (beats/minute)
Organism	Average Rate	Normal Range
Human	70	58 - 104
Cat	120	110 - 140
Cow	65	60 - 70
Dog	115	100 - 130
Guinea Pig	280	260 - 400
Hamster	450	300 - 600
Horse	44	23 - 70
Rabbit	205	123 - 304
Rat	328	261 - 600

Vessels

A vessel is a hollow tube for transporting something, like a garden hose transporting water. A blood vessel is a hollow tube for transporting blood. There are three main types of blood vessels:

• Arteries
• Capillaries
• Veins

These main blood vessels function to transport blood through the entire body and exchange oxygen and nutrients for carbon dioxide and wastes.

The arteries carry blood away from the heart, and are under high pressure from the pumping of the heart. To maintain their structure under this pressure, they have thick, elastic walls to allow stretch and recoil. The large pulmonary artery carries unoxygenated blood from the right ventricles to the lung, where it gives off carbon dioxide and receives oxygen. The aorta is the largest artery. It carries oxygenated blood from the left ventricle to the body. The arteries branch and eventually lead to capillary beds.

The capillaries make up a network of tiny vessels with extremely thin, highly permeable walls. They are present in all of the major tissues of the body and function in the exchange of gases, nutrients, and fluids between the blood, body tissues, and alveoli of the lungs.

Mammalian Heart External View Mammalian Heart Internal View

At the opposite side of the capillary beds, the capillaries merge to form veins, which return the blood back to the heart. The veins are under much less pressure than the arteries and therefore have much thinner walls. The veins also contain one-way valves in order to prevent the blood from flowing the wrong direction in the absence of pressure. The pulmonary vein returns oxygenated blood from the lungs to the left atria. The vena cava returns blood from the body to the right atria. The blood that is returned to the heart is then recycled through the cardiovascular system.

Comparative Anatomy

Mammals and Birds

Mammalian and avian hearts have four chambers – two atria and two ventricles. This is the most efficient system, as deoxygenated and oxygenated bloods are not mixed. The right atrium receives deoxygenated blood from the body through both the inferior and superior vena cava. The blood then passes to the right ventricle to be pumped through the pulmonary arteries to the lungs, where it becomes oxygenated. It returns to the left atrium via the pulmonary veins, this oxygen-rich blood is then passed to the left ventricle and pumped through the aorta to the rest of the body. The aorta is the largest artery and has an enormous amount of stretch and elasticity to withstand the pressure created by the pumping ventricle. The four-chambered heart ensures that the tissues of the body are supplied with oxygen-saturated blood to facilitate sustained muscle movement. Also, the larger oxygen supply allows thesewarm-blooded organisms to achieve thermoregulation (body temperature maintenance).

Amphibian Heart External View Amphibian Heart Internal View

Amphibians and Reptiles

Amphibians and reptiles, by contrast, have a three-chambered heart. The three-chambered heart consists of two atria and one ventricle. (The crocodile is sometimes said to have a four-chambered heart. The separation of the ventricles is not complete, however, because a hole remains in the septum (wall) that divides the two chambers.) Blood leaving the ventricle passes into one of two vessels. It either travels through the pulmonary arteries leading to the lungs or through a forked aorta leading to the rest of the body. Oxygenated blood returning to the heart from the lungs through the pulmonary vein passes into the left atrium, while deoxygenated blood returning from the body through the sinus venosus passes into the right atrium. Both atria empty into the single ventricle, mixing the oxygen-rich blood returning from the lungs with the oxygen-depleted blood from the body tissues. While this system assures that some blood always passes to the lungs and then back to the heart, the mixing of blood in the single ventricle means the organs are not getting blood saturated with oxygen. This is not as efficient as a four-chambered system, which keeps the two circuits separate, but it is sufficient for these cold-blooded organisms.

The heart rate of amphibians and reptiles is very dependent upon temperature. For example, the following table gives the approximate heart rate of a crocodile at the indicated temperatures. Notice that the higher the temperature, the faster the heart beat.

Temperature (Celsius)	Average Rate (beats/minute)
10 C	1 - 8
18 C	15 - 20
28 C	24 - 40
>40 C	Irreversible cardiac damage

Fish Heart External View Fish Heart Internal View

Fish

Fish possess the simplest type of true heart – a two-chambered organ composed of one atrium and one ventricle. A rudimentary valve is located between the two chambers. Blood is pumped from the ventricle through the conus arteriosus to the gills. The conus arteriosus is like the aorta in other species. At the gills, the blood receives oxygen and gets rid of carbon dioxide. Blood then moves on to the organs of the body, where nutrients, gases, and wastes are exchanged. There is no division of the circulation between the gills and the body. That is, the blood travels from the heart to the gills, and then directly to the body before returning to the atrium through the sinus venosus to be circulated again. The heart rates of fish fall within the wide range of 60-240 beats per minute, depending upon species and water temperature. The fish's heart rate will be slower at lower temperatures.

Conclusion

The cardiovascular system of animals consists of the heart and blood vessels. It is responsible for providing each cell of the body with the oxygen and nutrients it needs, while removing waste products.

Cyclotron

A cyclotron is a type of particle accelerator. Cyclotrons accelerate charged particles using a high-frequency, alternating voltage (potential difference). A perpendicular magnetic field causes the particles to spiral almost in a circle so that they re-encounter the accelerating voltage many times.

Ernest Lawrence, of the University of California, Berkeley, is credited with the development of the cyclotron in 1929, though others had been working along similar lines at the time

Atomic Clock

An atomic clock is a type of clock that uses an atomic resonance frequency standard as its timekeeping element. They are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, and to control the frequency of television broadcasts and GPS systems.

In August 2004, NIST scientists demonstrated a chip-scaled atomic clock.^[8] According to the researchers, the clock was believed to be one-hundredth the size of any other. It was also claimed that it requires just 75 mW, making it suitable for battery-driven applications. This device could conceivably become a consumer product.

In March 2008, physicists at NIST demonstrated optical atomic clocks based on individual mercury and aluminum ions. These two clocks are the most accurate that have been constructed to date, with neither clock gaining nor losing at a rate that would exceed a second in over a billion years.