Meteors Case Study Essay

Meteorites are rocks from space, which land on Earth, attracted by her gravity. The shooting stars that you see at night, are actually burning meteors that fall on Earth from outer space! This is the first of many interesting facts that are going to follow. Why do meteorites fall? For the same reason why anything falls on Earth – ‘Gravity’. Very few can escape it! Meteorites have their origin in outer space. They are relatively small pieces of dust and debris, usually left behind in the wake of a comet. Meteorites, that are huge in size, have their origin in space, as asteroids. They are left over pieces of matter from formation of the solar system, which could not clump together to form a planet like our Earth. There is a dense belt of such asteroids outside the orbit of the planet Mars, called the ‘Asteroid Belt’. Asteroids are huge in size and their lengths can number to kilometers! Once in a while, small pieces of rock or dust, come into range of Earth’s gravitational pull and fall on Earth as shooting stars. An asteroid dislodged from its trajectory and falling on Earth is also called a meteorite. However, an asteroid being huge in size, causes a cataclysmic explosion on Earth on impact. Origin ‘Meteor’ and ‘Meteorite’ facts are interchangeable terms and we shall see why they are so. When these rocks and pieces of dust are floating in space, they are called ‘Meteoroids’. When they make a blazing entry into Earth’s atmosphere, they are called ‘Meteors’. Finally, if they survive the burning entry into Earth’s atmosphere and fall on Earth, they are called ‘Meteorites’. So a meteorite could originate from comet debris called meteoroids or larger objects called asteroids! Here are some basic facts about meteorites, meteors and meteoroids. Comets leave tons of dust and debris in their trail as they travel along long orbits round the Sun. When Earth, while revolving around the Sun, passes through some patches of this comet debris, it enters the Earth’s atmosphere causing meteor showers. Meteor showers are periodic events. One can see thousands of meteors or shooting stars, as they are called, during such a shower. The most popular meteor showers are ‘Perseids’ (which peak around August 12) and Leonids (which peak around 17 November). During these showers, you can observe a shooting star at the rate of 1 meteor per minute on an average. A falling meteor can travel at speed of as much as 44 miles per second ! One of the facts is that they have some of the oldest rocks in the solar system among them. They could be older than the Earth and date from the period when Sun was forming! Every day, about 4 billion meteoroids fall on Earth! Majority of them are very tiny and therefore do not cause much harm. If a meteorite is observed while falling and recovered from the place of fall, it’s called a ‘fall’ meteorite. If a meteorite is not observed while falling, but found from any location, it’s called a ‘find.’ Till 2006, there have been roughly 1,050 witnessed falls while there are about 30,000 documented ‘Finds’. Falling meteors which are large in size, can create an intense electromagnetic pulse, which temporarily disrupt radio communication in the region of fall! With a properly designed radio antenna, you can actually ‘hear’ meteorites falling as radio noise. Types and Composition Here are some facts about their types and composition, that you should know about. Recovered meteorites are classified into three main categories which are ‘Chondrites’ (Make about 86% of all recovered meteorites), ‘Achondrites’ (8%) and ‘Iron’ meteorites (6 %). The name ‘Chondrites’ comes from features called ‘Chrondules’, which are melted silicate materials from their past. Chondrites are about 4.55 billion years old and are the types of rocks from which our own planet formed! Certain chondrite meteorites fallen from outer space contain traces of amino acids and organic matter, bolstering the theory that life may have been planted on Earth! This is one of the most astounding facts. Achronidtes are relatively younger meteorites of the igneous rock type and are pieces of asteroids, the Moon and Mars! Iron meteorites are composed of iron-nickel alloys and silicate materials. They are also thought to be pieces of asteroid s! Every one of these meteor facts are intriguing. Earth has been pounded by the impact of many meteorites, ranging from the very tiny to gigantic meteorites. The meteorites impact craters that are found on earth are testimony to this. It is time for the last of our facts. One gigantic meteorite impact occurred millions of years ago on Earth which brought on the extinction of dinosaurs! One question that may come to your mind is, ‘Where do meteorites fall?’. They could fall anywhere on Earth. Meteors have been found all over the world. The recent findings have been mostly in Africa and accessible parts of Antarctica. If you could find one, you are bound to be rich as private collectors and museums pay millions of dollars for them! The reason is that they are very rare and are made up of minerals, which are never found on Earth! So keep looking! You may never know, when one might pop out of the sky, making you rich. So it’s actually profitable to know some meteor fact s. Originating in the outer space, an object reaches Earth and gets a place in the list of meteorites. There have been many instances of extraterrestrial bodies impacting the Earth’s surface while some have only passed through the Earth’s atmosphere before they were destroyed. Meteorites have been arousing interest of the masses as there is an element of mystery that surrounds them. Where do they originate? What makes some of them enter the Earth’s atmosphere? How dangerous can they get? Space research and astronomy have revealed some interesting information about some of these questions and researched thoroughly on the different types of meteorites. Most of the meteorites disintegrate before reaching Earth while some reach the planet’s surface. Huge meteorites form craters on Earth while the smaller ones involve less danger. Meteorites containing small round particles are known as chondrites and form about 86% of those falling on Earth. Those similar in appearance to small igneous rocks are called achondrites and believed as being the crustal material of a steroids. Meteorites originating from the core of asteroids are known as iron meteorites and form about 5% of the meteorites, which fall. History has recorded a number of instances of meteorites impacting the Earth. ALH 84001: It was found in the Allan Hills, Antarctica in December 1984. Meteorite hunters of the United States working on ASMNET project discovered this meteorite. When discovered, its mass was 1.93 kilograms and its rock was reportedly one of the oldest forms. This meteorite was supposed to have come from Mars. Later it was believed to consist of some traces of the life on Mars and this made ALH 84001 more famous than ever. Hoba: This meteorite lies on the farm Hoba West in Namibia and has never been moved elsewhere because of its exceptionally greater mass. With a mass of about 60 tons, it is the largest meteorite known to mankind. It is tabloid in shape and composed of metal. It is believed to have landed on Earth about 80,000 years ago. In 1955, it was declared as a national monument and has since then been attracting visitors from different parts of the world. Tunguska Event: The Tunguska explosion took place in June 1908 near Tunguska River, now a part of Russia. Most probably, the air burst of a large meteorite caused this explosion. The energy emitted from this explosion was about 1000 times greater than that of the bomb blast of Hiroshima. According to the eyewitnesses of this explosion, the event started with a flash of bright blue light and a sound originating from east and moving northward. Later the sound was accompanied by shock waves that broke windows miles away. This was one of the famous disintegrating meteorites that remain in the list of world’s most famous meteorites. Willamette Meteorite: This is an iron-nickel meteorite that was discovered in the United States near Oregon. It is the largest of the meteorites found in the United Sates as also the sixth largest in the world. Probably the meteorite had landed in the region, which is now known as Canada. This meteorite weighing about 15.5 tons is one of the very large meteorites of the world. Orgueil: This meteorite fell in France in 1864 and is a relatively older meteorite. The fall of this meteorite consisted of small stones that covered a massive area. This is one of those eight meteorites that belong to the CL chondrite group. A striking feature of this type of meteorite it that its composition is similar to that of the Sun. This meteorite is one of the most researched ones. For purposes of deeper study of the composition of this meteorite, it was split into pieces. Currently, it exists in the form of pieces kept in different museums in Europe and the United States. These were some of the famous meteorites of the world. They have always been a subject of interest for researchers around the world. Meteor showers A meteor shower is a celestial event wherein it is observed that a group of meteors radiate from anyone point in the sky. This phenomenon is also known as ‘Meteor Storm’ or ‘Meteor Outburst’. The meteors that are present in the showers are actually cosmic debris that enter the Earth atmosphere at very high speed and vaporize very quickly due to friction leaving behind a streak of light which is known as the meteor shower. An identified meteor shower is usually an annual affair as the Earth will encounter the same meteors at approximately the same time and same speed every year. Causes Meteor showers are a result of interaction that takes place between the planet Earth and a comet. Comets consist of ice and rocks (often termed dirty ice balls) that orbit around the sun like planets. Every time the comet gets close to the sun, some of the ice present in the comet melts which produces a large amount of debris. This debris moves away from the comet and becomes a part of its tail which is visible part of the comet. The solid parts of the tail are the meteoroids and they spread along the entire orbit of the comet which is termed as a meteoroid stream. As the Earth orbits around the sun, its path may cross the meteoroid stream and a meteor shower follows. When the meteoroid stream is particularly dense, then we get to witness the meteor storm and having witnessed one myself, I can guarantee that the sight is truly spectacular. People Behind the Concept It is believed that Irish astronomer George Johnstone Clooney collaborating with the British astronomer Arthur Matthew Weld Downing and Adolf Berberich belonging to the Royal Astronomical Computation Institute in Berlin, Germany offered the very first idea of the meteoroid stream in the 1890. They were able to calculate as to how the meteoroids once freed from the comet would travel at low speeds when compared to the comet itself would start drifting after completing one orbit. This effect was attributed to simple orbital wherein the materials drift laterally away from the comet as some particles make a wider orbit when compared to other particles. The gravitational pull of the Earth’s atmosphere would decide where the dust trails would pass the Earth’s atmosphere. It is a fair possibility that some years, the dust particles can completely miss the Earth’s orbit. Major Meteor Showers If you want to watch meteor showers then the best time of the year is the night of January 3. The shower has been named Quadrantids and this particular shower can produce over a close to 140 meteors per hour. The source of this shower is not a comet but a minor planet, 2003 EH1 which suffered a catastrophic breakup in 1490. However, the showers are very faint and the peak hours last only for a few hours. Hence, you will have to be in a good spot and at an ideal point to watch the shower in all its glory and the best place to watch this particular shower is from the Northern Hemisphere. But people in Southern Hemisphere need not be disappointed. As a matter of fact, they get to witness a meteor shower termed Eta Aquarids which consists of debris from the famous Halley’s Comet. This shower peaks on the night of May 5 and the rate of meteors is about 30 per hour. The meteor shower ‘Geminids’ is considered to be the best annual shower. It peaks around the night of December 13 and the rate of meteor is around 70 per hour. The source of this shower is also a minor planet, 3200 Phaethon. It is best visible from the Northern Hemisphere and it is believed that due to the extreme cold conditions, the air tends to be more transparent and this is the reason as to why this particular shower is spectacular. Sporadic Meteor Showers When the meteoroids collide with each other and can become a part of the sporadic meteors background. They form isolated meteors and are not a part of any shower. Asteroids Asteroids are considered to be remnants of an early broken planet of the solar system. Asteroids have no fixed shape and are too small to be spherical in shape. They are ellipsoids (two dimensional figure), dumbbell or irregularly shaped. As they have different shapes, they also vary in their size. The first asteroid Ceres, discovered in January 1801 by Italian astronomer Giuseppe Piazzi, is the largest known asteroid and is 940 km in diameter. Some of the smallest asteroids are just 6 meters in diameter. The mass of all the asteroids added together, is believed to lesser than the mass of the Moon. Only 200,000 asteroids have been discovered so far, but billion more undiscovered asteroids still exit in our solar system. Asteroid Belt Most asteroids lie in the asteroid belt between Mars and Jupiter, however there are more belts in the solar system, namely the ones beyond Neptune’s orbit. The belt itself has interesting origination theories. Most astronomers believe that the belt is a broken planet, while some say that the belt is primordial material that never coalesced into a planet because of Jupiter’s gravitational pull. The asteroid belt lies between the orbits of Mars and Jupiter and contains more than 200 asteroids larger than 100 km in diameter, and more than 750,000 asteroids with diameters larger than 1 km. Most asteroids are found in this belt because of the gravitational interaction between the solar system and the celestial bodies in it. As opposed to the fiction made popular by various depictions of the asteroid belt, it is not at all dense. The region is so vast that asteroids are hundreds of thousands of kilometers away from their closest neighbor. The asteroids are so small and far away from each other that they appear as faint stars, and except for Ceres, are not bright enough to be seen without some telescopic aid. Only the asteroid Vesta, on rare occasions of an extremely clear dark sky can become visible to the naked eye. What are Asteroids Composed Of? Asteroids are made of different minerals and substances. This depends on the planet they broke away from in a collision, as well as the chemical reactions they might have experienced while orbiting in the solar system. The asteroids closest to the Sun are mostly carbonaceous and the ones further away are composed of silicate rock. The metallic asteroids are made of 70-80% iron and the remaining is nickel with many other metals such as iridium mixed in. Some are also made of half silicate and half metallic. The asteroid Ceres is composed of a rocky core covered by an icy mantle, whereas Vesta has a nickel-iron core, basaltic crust and a covering of magnesium iron silicate (olivine mantle). Asteroids composition has been classified as the following: C class asteroids: They are found in the Earth’s outer belt and are darker and more carbonaceous than the ones found in the S class. D class asteroids: They are also known as Trojan asteroids of Jupiter and are dark and carbonaceous in composition. S class asteroids: They are found in the Earth’s inner belt, closer to Mars and are composed of mostly stone and iron. V class asteroids: They are a far-out group of asteroids that follow a path between the orbits of Jupiter and Uranus, and are made of igneous, eruptive materials. A near-Earth asteroid collided with the Earth about 65 million years ago, which triggered environmental changes, leading to the extinction of the dinosaurs. This asteroid created a huge circular depression called the Chicxulub Basin and is centered in Mexico’s Yucatan Peninsula, a major tourist attraction. Though the chances of asteroid collision with the Earth is very rare, they do come very close to our planet due to collisions and gravitational tugs on the highly elliptical Sun’s orbit. Most asteroids burn up in the atmosphere and never reach the Earth. NASA projects, such as the Lincoln Near-Earth Asteroid Research (LINEAR) and the Near Earth Asteroid Tracking (NEAT) main objectives are to detect and intercept asteroids or other celestial bodies coming close to the Earth before they cause untold damage to our planet. Asteroids are small celestial bodies composed of rock and metal, that revolve around the Sun. Their size can vary: some asteroids are large and roughly spherical in shape, due to which they appear like miniature planets; while the others are small and irregularly shaped. The matter of these celestial bodies also differs. The asteroid ‘Vesta’, is believed to have a nickel-iron core, olivine mantle and basaltic crust, while the asteroid ’10 Hygiea’ is composed of carbonaceous chondrite. Most of the small asteroids are piles of rubble held together by gravity. Some asteroids supposedly have traces of amino-acids and other organic compounds, and it is assumed that the impact of asteroids on the Earth could have initiated life on the planet by seeding it with the necessary chemical substances. Although, it is believed that the asteroids may have planted life on the Earth, they are capable of having catastrophic effect on the planet as well. Asteroids with a diameter of 5 to 10 meters, and energy equal to 15 kilotons of TNT, enter into the Earth’s atmosphere approximately once every year; while, those with a diameter of over 50 meters enter the Earth’s atmosphere approximately once in a thousand years. Their impact can be devastating if they hit the Earth, but they disintegrate in the upper atmosphere and most of the particles are vaporized, thus rendering them harmless. In the distant past, our planet has experienced a massive climate change and large-scale extinction of animal and plant species, ascribed to the impact of some large asteroids on the planet. The exogenesis theory suggests that origin of life on the Earth must have been triggered by the impact of some asteroid, carrying organic chemicals needed to initiate life form. The Cretaceous-Tertiary extinction event, which led to the end of dinosaurs and the Permian-Triassic extinction event that led to the end of the Permian period finishing off 90% of the species on the planet, are believed to be the result of an asteroid impact on the Earth. The craters on the solid bodies in the solar system, which were attributed to volcanic activities till 1960s, were actually formed due to the impact of celestial bodies. Researchers have determined that in the last 600 million years, 60 objects with a diameter of five km or more, have struck the Earth. Even the smallest of these object possessed energy of ten million megatons of TNT, and would have formed a crater, approximately 95 km in diameter, on the surface of our planet. The Rio Cuarto craters in Argentina are believed to have formed due to the impact of asteroids that struck this area around 10,000 years ago. In 1490, ten thousand people reportedly lost their lives due to a hail of stones from the sky. This hail of stones is assumed to be result of the disintegration of a large asteroid, after it entered the Earth’s atmosphere. In 1908, a mid-air explosion of an asteroid destroyed 80 million trees, within an area of 830 miles, near the Podkamennaya Tunguska River, in Si beria. In many cases, the sighting of a foreign body, such as an asteroid or a meteoroids is reported as a fireball in the sky. Millions of asteroids will pass by the Earth in the years to come. Though, they are unknown now, they are detectable as they come closer to the planet. The Lincoln Near-Earth Asteroid Research (LINEAR) and the Near Earth Asteroid Tracking (NEAT) are projects initiated by NASA to detect asteroids or other such foreign bodies coming close to the Earth. The need of the hour is to develop an intercept system in space, to destroy or deflect foreign objects heading towards our planet, before they prove catastrophic. Asteroids are celestial bodies consisting of rocks and metals. They are mainly concentrated in the region known as the asteroid belt which lies between the orbits of Mars and Jupiter. Asteroids can be as big as Ceres, which is close to 1000 kilometers in diameter, or can be just a few feet in diameter. Whatever the size, asteroids are neither big enough to be called planets nor are they as small as comets. They are classified as minor planets that include the Kuiper Belt Objects. Discovery On January 1, 1801, Giuseppe Piazzi discovered the first asteroid which he initially thought to be a comet. He named this asteroid Ceres, after the Sicilian Goddess of grain. Ceres is also the largest asteroid to have been discovered so far. Soon, other large asteroids like Pallas, Juno and Vista were discovered. By the end of the 19th century, several hundred asteroids were discovered. Formation of Asteroids It was once believed that asteroids were formed by the explosion of a planet orbiting between Mars and Jupiter. However, according to present day astronomers, asteroids are debris left behind by the Big Bang that could not come together to form a tenth planet because of the effect of Jupiter’s gravitational pull. Asteroid Hits Asteroids have been hitting the Earth since millions of years. However, due to the friction with Earth’s atmosphere most of the asteroids get burnt. The asteroids that enter the Earth’ s atmosphere are called meteors while the ones that get burnt and appear as shooting stars are called meteorites. According to the Giant Impact Theory, the Moon was created when Theia, an asteroid of the size of Mars, collided with the Earth in the early days of the solar system. However, some consider Theia to be more of a planetoid than an asteroid. The largest crater caused by an asteroid hit is the Chicxulub Crater in Mexico that is 180 km in diameter. The asteroid that formed the crater had a diameter of 10 km. This collision is supposed to be responsible for the extinction of a large number of flora and fauna including the dinosaur. However, the evidence of the largest asteroid hit is in the Vredefort crater in South Africa that is 300 km in diameter. Impacts of Asteroid Hits The damage that an asteroid’s impact can cause depends mainly upon its mass and velocity, as these are the two factors that determine the energy that is released when an asteroid hits the Earth. While some asteroids are capable of sending thermal waves that can incinerate most flora and fauna within a few hundred kilometers, some larger asteroids can create huge impacts causing magma to cover areas as big as continents. The worst effect of an asteroid hit is the blocking out of sunlight for months together due to formation of dust clouds and soot in the upper atmosphere. This would hamper the green plants’ ability to prepare food through the process of photosynthesis and the food chain would be disrupted. Near-Earth Asteroids Near-Earth asteroids are those that have moved closer to the Earth’s orbit as they have been knocked out of the asteroid belt due to collision with other asteroids or comets, or due to the gravitational forces of Jupiter. They are classified into the following three groups: The Amors: These are near-Earth asteroids that cross the orbit of Mars but do not go out of the Earth’s orbit. The Apollos: The orbits of these near-Earth asteroids cross the Earth’s orbit but have an orbital period of greater than one year. The Atens: These near-Earth asteroids have orbits that cross the Earth’s orbit but have an orbital period of less than one year. Asteroids are currently being monitored for their probability of colliding with the Earth. Such studies have predicted that asteroids may hit the Earth on February 1, 2019 and March 16, 2880. The probability of the 2880 collision is as high as 1 in 300. A number of projects in the field of astronomy, like Spacewatch, Near-Earth Asteroid Tracking and Catalina Sky Survey are being carried out to detect any threat of such catastrophes. Comets A comet is a small body in space. It was matter of great interest to astronomers like Sir Edmond Halley. Many decades later, comets still remain a challenging mystery for the field of astronomy. Space research institutes around the world have reported the existence of 3628 comets that are known and studied. Annually, an average of one comet is sighted by the naked eye from the surface of the Earth. According to the definitions given by the various space research organizations, a comet can be defined as a space body that travels in an elliptical orbit around the sun. Most of the comets travel in elliptical orbits. When the comet comes in the vicinity of the star it is orbiting around, its comma-like tail gets illuminated. A majority of comets are visible only through telescopes and other aids. There are however, some comets which are also visible to the naked eye. What is a Comet Made Up of? A comet is principally made up of ice, dust and different forms of gases. The nature of the components differs from comet to comet. The central part of a comet that looks like a ball is termed as the nucleus. The nucleus is principally made up of ice and frozen gases. The frozen components also include many other compounds like ammonia, methane and carbon dioxide. Rocks are another component of the nucleus. Due to such composition, the nucleus of the comet often resembles a huge ball of dirt and snow. It is also believed by some astronomers, that the nucleus of a comet is rather fragile because several comets have split into parts without any explainable reason except immense velocity. The huge elliptical orbit takes the comet in the range of heat of the star around which it is orbiting. When the comet enters the inner parts of the solar system, the frozen content of the nucleus starts melting. The gases and water within the nucleus vaporize as a result of radiation from the star and the solar wind. The immense velocity of the comet and the solar wind, push the vaporized matter away from the nucleus. This gives the comet it’s distinct tail and the comma-like appearance. The high amount of heat and the ions (charged particles that are formed due to the heat of the sun) cause the tail of the comet to glow. How are Comets Formed? According to their formation or birth, the comets can be classified into two types. The first type is short-term comets which originate in the Kuiper belt as space bodies beyond the orbit of Pluto. The gravitational pull of the planets in the solar system, causes the origin of short term comets. These comets enter the solar system and take the form of active and glowing comets. Long term comets originate as traveling bodies in the Oort cloud (located around 50,000 light years away from the sun). The gravitational attraction of the planets in the solar system and other gravitational forces cause these comets to form elliptical orbits. Death of a Comet The study of comets has revealed that they have a fragile structure. Sometimes, comets split into parts due to sheer velocity. The entry and exit of comets in the solar system in course of its orbit, reduces the amount of matter (ice and frozen gases) in it. Due to this reduction in matter, the comets break-up and disperse into clouds. A dead comet is nothing but an asteroid or a similar form of a space body. Sometimes the comets also crash in other planets when their orbits cross each other. The most famous example of such a comet is the Shoemaker Levy 9, that crashed into Jupiter. For astronomers who have spent their lives studying comets, it a very heart-breaking moment to gaze at a dying comet. The Halley’s Comet is said to be one of the most beautiful comets. Another very beautiful comet is the Hale-Bopp, that was discovered in the year 1995, on 23rd July. It was predicted by astronomers that the Halley’s Comet would be sighted in the November of 1835. Mark Twain, the famous writer, was born just two weeks after the sighting. He developed a very special liking towards the Halley’s Comet. In his biography he comments,†I came in with the Halley’s Comet, and expect to go with it. The Almighty has said no doubt, Now here are two unaccountable freaks; they came in together; they must go out together.† Halley’s Comet was next sighted on 20th April, 1910. Twain ended the journey of his life the very next day. The journey of any comet is indeed like that of Mark Twain. It is remarkably long, fast, adventurous as it streaks across the dark sky. Haley’s comet Historical Spottings British scientist, Edmond Halley who observed the comet in 1682, was the first person to establish its periodic reappearance after every 75-76 years. He studied the comet and quite accurately predicted that it had earlier appeared in 1531 and in 1607. It was named ‘Halley’ in his honor and was observed again in 1758 as stated by him. It was last seen in February 1986. However, this was not the first time the comet was in focus. The first sighting recorded, was way back in 240 BC, by the Chinese and was mentioned in a chronicle, ‘Records of the Great Historian’. The comet also finds a mention in a Babylonian clay inscription of 164 BC. It has always been a subject of great interest, since it was believed to have an influence on the contemporary events. Armenian king Tigranes II, had its image printed on the coins issued in his regime after it was sighted in 87 BC. Therefore, even though the recurrence of the comet was an unknown fact, people were fascinated b y its appearance. The bright star that appeared in the night sky in 12 BC, coinciding with the birth of Jesus, is widely believed to be the Halley’s comet. Giotto Di Bondone, the famous Italian painter, who lived before the renaissance era, painted it in his work ‘The Star of Bethlehem’ in the Nativity, in 1305. He had seen the comet appear in 1301 and was impressed by the spectacle. In the middle ages, the appearance of a comet was considered to be a warning sign of a forthcoming danger. The most famous incident of spotting a comet during this period, was in 1066, before the Battle of Hastings. King Harold who had lost the battle, was believed to have seen the comet due to which he was cursed. In fact, the Bayeux Tapestry in Normandy, France, signifies the Norman victory in this battle with an image of King Harold looking at the comet in the sky. In 1456, Pope Calixtus III had condemned its appearance considering it to be an evil omen. Three years prior to this, Europe was defeated by the Ottoman Empire. Human beings have always blamed celestial phenomena, whenever they have not been able to explain the causes of certain unfavorable events. Historically, the presence of a comet in the night sky was commonly cited as the reason behind difficult situations that were beyond the reasoning of common man. A French physician, Ambroise, had described the pitiful conditions of middle ages, when a comet was seen just before the spread of a big epidemic. According to him, some people were scared to death while others fell sick on seeing the comet. It was believed to be some ‘evil form’ leaving behind a trail of blood, believed to be a sign of misery. Recent Spottings In the 16th and the 17th century, scientists learned to calculate the speed and distance at which comets travel around the Sun. Once, Edmond Halley had established the year of its reappearance, Halley’s comet became a matter of great interest. Although, he didn’t live to see his prediction coming true, his observation had a significant impact on the way society perceived comets. The sighting of a comet, especially Halley’s comet became less of a concern and more of a curiosity among people. Once people realized that comets are orbiting bodies just like planets, they became less apprehensive on the arrival of a comet in the Earth’s visibility zone. The change in the attitude of the people was seen in the depiction of the comet in the contemporary pictures. Halley’s comet was a subject of scientific study and was depicted as a beautiful heavenly body in the sky. Famous American writer Mark Twain was born in 1835, the year when Halley’s comet ha d appeared. He predicted in 1909 that since he had ‘come’ with the comet he will ‘go out’ with it. Sure enough, he passed away a year after the comet reappeared in 1910. In the 1900s, it had appeared twice; once in 1910 and then in 1986. Further studies gave us a deep insight into the structure, composition and orbital journey of many different comets. Halley’s comet has one of the shortest orbital paths. It is classified as a short period comet, i.e. comets having an orbit period of 200 years or less. Once upon a time, it belonged to the long period class, but due to the gravitational force of planets, its orbit shortened over a period of time. Today, it is known that comets like ‘Hale Bopp’ which appeared in 1997, will reappear after 4200 years! Thus, Halley’s comet is the most frequently spotted one. Recently, it was seen in February 1986. During this visit, it was subjected to its biggest scrutiny ever. Five spacecrafts from The European Space Agency, Japan and the USSR were launched to study its surface. Structure and Composition of Halley’s Comet Halley’s comet is a big mass of ice and dust, having an elliptical orbit and shaped like a peanut. It has a highly elongated orbit, taking it very close to the Sun. It flings off far in the outer solar system, similar to a slingshot motion. The composition is mainly of water, sodium monoxide, methane, ammonia, hydrocarbons, iron and sodium. Its closest distance from the Sun was found to be just 0.6 AU (astronomical unit) and the farthest distance was calculated to be 35 AU, roughly the same distance as that of Pluto. It orbits the Sun in a retrograde or in the direction opposite to that of the planets’ revolution. The speed with respect to the Earth is quite high, since it is highly eccentric and inclined. The day time is relatively more on its surface and its maximum temperature rises up to 77 degrees celsius. Due to its large size and a well-defined and regular orbit, it was easy for the probe missions photograph it closely and study its surface. The mass of the comet is 1.7Ãâ€"1015 kilograms and the size of the nucleus has been estimated to be 15 km Ãâ€" 7 km Ãâ€" 7 km. Winds blowing near its surface are so strong that 1 gram particle of dust which hit the Giotto space probe, briefly destabilized it. Halley’s comet will next appear in 2062. Comets have always been a fascination for human beings and will continue to mesmerize generations to come, as we discover more interesting facts about these spectacular fireballs, the comets. Comet lullin Comet Lulin was discovered on July 11, 2007, by the duo of Ye Quanzhi and Lin Chi-Sheng. A non-periodic comet, Lulin appears to be greenish in color. This green color is attributed to the presence of gases such as cyanogen and diatomic carbon, which produce a green glow when illuminated by sunlight in the vacuum of the space. Officially designated as C/2007 N3 (Lulin), it is also known as the ‘Comet of Cooperation’ in China and Taiwan, as the two individuals involved in its discovery, were from these two countries. This comet was first photographed by Taiwanese astronomer Lin Chi-Sheng on July 11, 2007, while he was working on the Lulin Sky Survey Project (LUSS) at the Lulin observatory in Nantou, Taiwan. The Lulin Sky Survey Project aims to identify the numerous small objects in the solar system, particularly those that pose possible hazards to our planet. Lin used a 16-inch telescope to photograph this comet, which was initially assumed to be an asteroid. A few days later, Ye Quanzhi, a 19-year old student of meteorology from Sun Yat-Sen University, China, recognized this comet while going through Lin’s photographs. Its status of being a comet was confirmed after the presence of coma, the nebulous envelope around the nucleus of the comet, was noticed. Both, Lin and Quanzhi were accredited with the discovery of this new comet. As it was first noticed from the Lulin Observatory, it was named as Comet Lulin. Comet Lulin was seen in the Libra constellation from January to March 2009. In January, it was getting brighter and could be seen just before dawn; while in February, the brightness reached its peak. Eventually, in March, it started to fade as it went farther away from the Earth. While it was approaching the Earth, it had a typical tail pointing away from the Sun, as well as an ‘anti-tail’ which was directly pointing towards the sun. Although, it was assumed that this anti-tail was observed only in photographs, so me observers reported that it was visible even from a telescope in February 2009. According to Brian Marsden, an astronomer at Smithsonian Astrophysical Observatory, Massachusetts, this comet’s closest approach to the sun was on January 10, 2009 when it reached a distance of 113 million miles from the sun. He noticed that the comet was moving in a retrograde orbit that is near-parabolic. On February 24, Comet Lulin came the closest to the Earth, at a distance of 0.41 AU or 38 million miles to be precise. On February 4, 2009, a team of Italian astronomers, under the leadership of Ernesto Guido, witnessed a strange phenomenon taking place in comet Lulin. While photographing the comet with a remotely controlled telescope in New Mexico, they saw that its tail suddenly disconnected. Ernesto attributed this odd phenomenon to magnetic disturbance of the solar wind hitting the comet. Earlier, this had been observed with Comet Encke too, when coronal mass ejection occurred, due to such magnetic storms. Photographs taken by NASA’s Swift Gamma-ray Explorer satellite in ultra-violet and X-rays show that Lulin is shedding 800 gallons of water every second. Observations by NASA also revealed that the surface material of the comet was burning away due to sun’s heat. This sighting of Comet Lulin was a once-in-a-lifetime opportunity for the whole world, as there is no possibility of this comet returning to the inner solar system, at least not for the next thousand years. Human kind has always looked to the heavens in awe and wonder, and sometimes in fear. Perhaps no other astronomical phenomenon except a total solar eclipse has historically evoked as much fear as comets. When the specter of fear is removed, however, they emerge as strikingly beautiful objects in the sky. It was once believed that if earth passed through a tail of a comet, its inhabitants would die; this theory has been discredited. Comets are messengers from a time long past. Most are chunks of dirty ice, locked away in the Oort cloud for billions of years. (Oort cloud: – It is the source for long period comets, with orbital periods of greater than two hundred years.) Comets are familiar to nearly everyone as striking star like objects with long tails stretching across a wide band of the sky. The most famous comet, Halley’s comet makes its return to the skies every seventy-five years. The word â€Å"comet† is derived from a Greek word meaning â€Å"long haired† Comets were greatly feared before the twentieth century as bad omens. Since then, they have been identified and cataloged as objects that come from deep space. Most of them occupy orbits that carry them far outside the solar system. Many of them make only a single approach to the sun and never return again, while others exist in stable, but highly elliptical orbits that allow them to return after an extended period of time, such as the Halley’s comet. In 1986, the European space probe Giotto passed about 600 kilometers from the Comet Halley as it made its close approach to the sun. The probe verified existing theories that comets are made up of ices covered by black dust or soil. The spacecraft confirmed a theory that had been advanced prior to the reconnaissance that described comets as â€Å"dirty snowballs.† Using data taken by the spacecraft, scientists determined that the dust is composed of carbon, hydrogen, oxygen, and nitrogen. Other metals have also been discovered in comets, such as iron, calcium, nickel, potassium, copper and silicon. Halley’s comet was one of the darkest objects ever seen in the solar system; it was basically flat black. Comets are composed of a mixture of ices and dust. As a comet approaches the sun, it absorbs the suns energy and warms up. The main body of the comet is called the nucleus. As the nucleus warms, the ice beneath the comets soil evaporates. Because the comet has no atmosphere, the evaporated substance (also called a volatile) escapes into the vacuum of space as a gaseous envelope that surrounds the comet called â€Å"coma.† As the coma grows, it forms a plume of vapor that carries away some of the comets surface as well. This mixture of evaporated volatile particles and dust is carried away from the comet by solar wind, is ionized by high-energy particles, and creates the spectacular tail of the comet. The comet’s tail, glowing in the solar wind, can stream behind the comet for millions of kilometers. The nucleus of the comet consists of mostly volatile ices and dust. The ice is nearly all water ice, but there is also evidence of ices composed of carbon dioxide and methane. More elementary compounds of nitrogen, oxygen, and carbon monoxide may exist as volatile ices. Comets are typically small bodies (comparatively!!). Halley’s comet is a potato shaped object, 14 by 17 kilometers. The largest known comet is Chiron, which is estimated to be approximately 200 kilometers in diameter. Comets are thought to have formed as the solar system evolved. The material of which comets are composed was constructed by accretion at the outer edge of the disk of material that ultimately became the sun and planets. Because the comet material was fashioned at the outer edge of the solar system, the sun did not evaporate the volatiles in the cometary material. At the same time, the giant planets of the solar system formed at what would become the outer orbits of the solar system. These massive planets encountered the newly formed comets, and the ones that were not engulfed by the giant planets were, over the first billion years, catapulted into interstellar space by the planets massive gravitational fields. Not all comets met that fate, however. Some were gently nudged into stable orbits closer to the sun. Others were flung into the inner solar system and impacted the inner planets. Relevance: – The study of comets involves detailed knowledge of its composition of the outer regions of the solar system and the space between the last planet and 100,000 astronomical units onwards. Cometary study also seeks to understand complex gravitational interactions between bodies separated by wide distances and even gravitational interactions between tiny comets, their behavior when approaching the sun, and something of the makeup and evolution of the early solar system. New comets approaching the sun for the first time have been held in deep freeze in the Oort cloud and are thought to be composed of primordial material of the newly forming solar system. They have been tied up in the Oort cloud for billions of years at temperatures slightly above absolute zero. As they approach the sun, their internal gases begin to steam away. A detailed study of an approaching comet may tell cosmologists about the composition of the early solar systems. Comets and their approach have also hinted at the existence of the elusive brown dwarf, thought to be one of the most common bodies of interstellar space. Because they are so dim, they are all but invisible from Earth. On the other hand, because brown dwarfs are thought to be so plentiful, the study of comets and their orbits may give the first real clues to the former’s reality and abundance. In the early 1980s the existence of the galactic tidal action was merely speculation. Since then, careful study of cometary orbits and approaches has favorable supported the theory of galactic tides. In the close approach of Halley’s comet by an unmanned spacecraft in 1986, a wealth of information was recovered on the shape, behavior, and composition of comets. The existence of the Oort cloud and the concept gravitational interactions by passing objects in space have led to the theory of periodic comet showers. Such comet showers, separated by periods of tens of millions of years, may be responsible for the mass extinction on Earth. There is a wide speculation that Earth was struck by one or more comets 70 million years ago, which wiped out the dinosaurs. Some scientists have speculated that this extinction was the result of a shower of comets from the Oort cloud, sent on their close approach to the sun by a passing star or brown dwarf through the Oort cloud. Comets have been used to judge vast distances, evaluate the composition of the solar system as it was being born, and even test the idea that the gravity of the entire galaxy can make a difference to the smallest objects in space. Comets have been used as yardsticks to evaluate what may be the most type of star in the galaxy-the brown dwarf-which ironically is one that may never be seen. They have also been called dirty snowballs. Halley’s comet was so black that it was the darkest object ever seen in space. Yet, from these dirty specks of ice, cosmologists have witnessed some of the most spectacular light shows. Ultimately comets may also generate clues to some of the most fundamental secrets about the solar system and planets. From these tiny messengers, cosmologists may unlock and examine pristine elements from creation itself.

Robert and the Dog

Language was born as an instrument to communicate people, to convey messages in many ways. According to the evolution of human beings, their language has been an evolution too and during this process literature emerged with an artistic interest to express feelings, thoughts and their imagination. But, what is literature? Many theorists have tried to explain that, and we have some patterns that are typical in their texts. In the text â€Å"Robert and the dog† by Ken Saro-Wiwa you can find some of this patterns such as the human being view, the disposition to analyze stories and the literature as an aesthetic object. To begin with, the first example is the concept of man that is given by the text. This is not about the generic male or female description is about the type of person in it. In the text we can see a men that is coward, insecure and with thirst of power. You can recognize this by the description of the character in the development of the story: the thirst of power is seen in â€Å"And he always repaired there nightly to exercise authority over his wife and six children. (Saro-Wiwa, 1) the insecurity in â€Å"Robert began to feel like a human being† (Saro-Wiwa ,page 3) and the cowardice in â€Å"He gathered up all the tins of dog food, all the tins of milk, tethered the dog to the settee and walked off, out of the house and the job he had loved to do. † (Saro-Wiwa, page 5). In these cases we can see that the author invites to get into the feelings of the character, giving a description of it. This is a clear example of a literary text, because by this he is describing a man that is typical in the actual lower classes. On the second case we can see the disposition to analyze the story. The author has a particular way to describe the principal character feelings about the dog. He shows us by a image what â€Å"Robert† thinks: â€Å"And when he got home in the evening and saw his children, with distended stomachs, gamboling in the filth that simmered in a swollen stream at his door, and watched them hungrily swallow small balls of eba, he asked himself, ‘Who born dog? † Saro-Wiwa, page 3) This description is not literal; you have to deduce it, according to the text. The author is trying to transmit to the audience the comparison that â€Å"Robert† is making with the dog, but not by words, instead he is using a shocking image of his children eating like dogs. That is were literature is present, in the way of telling and describing the thoughts of the character. In any other text the comparison is literal, but not in literature. On the last example we analyze the literature a s an aesthetic object. Literature, as a written representation of art, has to follow the basic concepts of aesthetic and, among others, there is the connection between its form and it’s content to make it beautiful. So, in the analyzed story this relation is present; the form of the text uses the language beyond the importance of giving a message, it makes it alter the grammar in order to give emphasis and sound to the text: â€Å"She ensured that he was well fed with tinned food and milk and meat and bones. (Saro-Wiwa, page 3) The word â€Å"and† is used too many times, and that grammatically it is incorrect, but in literature it is not a problem. The repetition of the word â€Å"and† is a way to explain that the dog has more than Robert, and this shows that â€Å"Robert† it is prisoner of his jealousy and his thirst of power. The language and the message, the content and form make this story a work of art that traps the lectors and transmites one of the worst parts of the human being. So, to sum up the text â€Å"Robert and the Dog† by Ken Saro-Wiwa is a literary piece, because of its form and content, the way of the language is used and the message that it contains. A non literary piece of writing is less emotional, and everything is literal, you do not have to conclude anything, but in this text the author uses a very particular way of explaining the feelings and thoughts of the principal character, using the aesthetic as a way for you to interpret every situation that he goes through. Also the vision of human being that is showed in this text, reflect that is a literary piece, because the author describes a men with a poor economical situation, but he never says it, you know that just for de description. On the last the use of a shocking image makes you think about how he sees his own life. So if you connect these three reasons you can see that in a literary text the most important parts of the writing are the ones that are not written; what you can infer, the moral that leaves you and the feelings of each person, and at the end that is what every work of art wants, it is the purest purpose of literature.

Adaptation Model of Nursing Analysis

Adaptation Model of Nursing Analysis Roy’s Adaptation Model One of the most prominent nursing theories is the Adaptation Model of Nursing, developed by Sister Callista Roy. It focuses on the human ability to adapt to environmental stimuli through our set of systems; biological, psychological and social. The main goal of this model is to live adequately by striving for balance. The Roy adaptation model interprets the person as a rounded adaptive system constantly interacting with the external and internal environment, with the goal to maintain integrity. According to (Roy and Andrews, 1999), adaptation refers to â€Å"the process and outcome whereby thinking and feeling persons as individuals or in groups, use conscious awareness and choice to create human and environmental integration†. There are three levels of adaptation described by Roy each representing the condition of the life processes; integrated, compensatory, and compromised life processes (Master, 129). An integrated life process that is lost may change to a compensatory process, which tries to reestablish adaptation. However if the compensatory process is not enough, it leads to compromised processes. There are two types of coping processes in Roy’s model; innate and acquired. Innate coping mechanisms are genetic, while acquired processes are learned. Coping processes are further categorized into applying to individuals; regulator and cognator subsystems. The regulator subsystem is biological responding through chemical, endocrine, and neural means. The body has a natural response to stimuli such as hormones, electrolytes etc. The cognator subsystem acts by four cognitive emotional channels: perceptual and information processing, learning, judgment, and emotion (Masters, 129). These subsystems main goal is to maintain the processes of life; integrated, compensatory or compromised. The input of the individual adaptive system comes from the environment. There are three classes of stimuli that Roy has ident ified. The focal stimulus is what the human is instantly aware of in their consciousness. Contextual stimuli are the other stimuli that contribute to the focal stimulus, but are not the focus of the human awareness. Lastly is the residual stimuli, which has unknown effects to the situation at hand. According to Roy’s model, understanding the health of the patient is based on understanding the environment, the adaptive system, and the scientific and philosophic assumptions. Responses made relative to the human goal of thriving promote wholeness of health. Health is both a process and a state of becoming whole and integrated. Assumptions from adaptation level theory and assumptions from systems theory have been combined into a single set of scientific assumptions. From systems theory, human adaptive systems are intermingling parts that cooperate together. Human adaptive systems are complex multifaceted and respond to myriad environmental stimuli to achieve adaptation. With their ability to adapt to environmental stimuli, humans have the capacity to create changes in the environment (Roy & Andrews, 1999). Drawing on characteristics of creation spirituality, Roy combined the assumptions of humanism and vertivity (common purposefulness of human existence) into a single set of philosophical assumptions. Humanism insists that human experiences are essential to knowing and that it has power in creativity. Vertivity affirms the belief in the purpose, value, and meaning of all human life. Roy defines nursing as a â€Å"health care profession that focuses on human life processes and patterns and emphasizes promotion of health for individuals, families, groups, and society as a whole† (Roy & Andrews, 1999, p.4). Nursing is what expands adaptive abilities and enhances person and environment. Nursing assesses of stimuli and behavior that influence adaptation. Based on these assessments, interventions are made to manage the stimuli. There are two types of nursing, a science and as a practice discipline. As a science, the goal to â€Å"develop a system of knowledge about persons that observes, classifies, and relates the processes by which persons positively affect their health status† (Roy, 1984, pp. 3-4). As a practice discipline one uses the scientific knowledge to promote health through an essential service (Alligood, 2014). Nursing facilitates adaptation by assessing behavior and intervening to promote adaptive abilities and to enhance environment interactions. According to Roy, humans are adaptive creatures. The human system is a whole with parts that work together to pursue a goal. These human systems include both the individual and the group. Humans systems adjust to the environment and in turn, affect the environment, due to their capability in consciousness and meaning. Roy defined the person as the main focus of nursing, the recipient of nursing care, a living, complex, adaptive system with internal processes (cog nator and regulator) acting to maintain adaptation in the four adaptive modes (physiological, self-concept, role function, and interdependence) (Alligood, 2014). â€Å"Health is a state and a process of being and becoming integrated and a whole person. It is a reflection of adaptation, that is, the interaction of the person and the environment† (Andrews & Roy, 1991, p. 21). Adaptation is a process to enhance psychological, physiological, and social integrity. Health can be perceived as a scale from extreme poor health to peak wellness. However both health and illness can co-exist, the goal of health is to cope with illness in a competent way. Health and illness are one inevitable part of the person’s total life experience (Alligood, 2014). When mechanisms for coping prove to be ineffective, illness persists. Through adaption one can achieve proper health. Environment is â€Å"all the conditions, circumstances, and influences surrounding and affecting the developme nt and behavior of persons or groups, with particular consideration of the mutuality of person and earth resources that includes focal, contextual and residual stimuli† (Roy & Andrews, 1999, p. 18). In order for adaptive responses to occur changes in the environment must be observed. These changes could be positive or negative, large or small, both internal and external factors. Mrs. Muriel Crane is a 74 year old female presenting to the emergency room because her breathing has become more difficult and she noted an increase in sputum production. Her family physician referred her to the ER for treatment of an acute exacerbation of COPD, a condition she has had for the last10 years. To summarize Roy’s model of adaption, it focuses on the human ability to adapt to various environmental stimuli, both innately and externally. In context to this model, she has various issues to discuss. These issues must be related to human adaptation to the environment/condition, or can b enefit from this theory. First, her breathing problems are a response to her body not being able to receive the oxygen she requires. Getting her oxygen up is a major focus. She is also suffering from a cough, spewing up thick yellow sputum which also keeps her up at night. She is constantly tired, with no energy for daily activities. Over the last month Mrs. Crane has been losing weight, but has no appetite, as she’s under a lot of stress. With a temperature of 39.2 she is experiencing a fever. During damp cold weather she feels arthritic pain in her knees. Lastly due to these symptoms and her hospital stay she has peripheral muscle wasting and muscle weakness. A key concept within Roy’s model is the idea of health and illness coexisting in the human life. For Mrs. Crane she has experienced a massive drain of energy due to this illness and is unable to participate in her daily activities. This is a major priority as it impedes on her quality of life, and limits the r ate at which she feels better. According to Roy, illness is natural and we must learn to coexist with it. For Mrs. Crane, she has no energy because her body is using it on other needs such as combating infection, or keeping up oxygen levels. To free up energy, a goal she can make is to prioritize her energy spending, as well as making a greater effort to engage in daily activities. By doing this, she can improve her quality of life as well as her psyche, which will improve her healing process. Adaptive behaviors are those that promote the goals of survival and adapting to the environment. However, Mrs. Crane is coughing leading to a lack of sleep. This adaption is negative to her health, and an ineffective behavior. Roy explains in her model that ineffective behaviors need to be recognized and purposely stopped. In order to stop this cough, she needs to take the proper medicines and alternative therapy, which will lead to a better sleep. This in turn will promote the goals of surv ival and healing. When faced with the stress of her illness, Mrs. Crane experiences the regulator subsystem of coping which responds with biological means. The body has a natural response to stimuli such as hormones, in this case cortisol. However she has been a great amount of stress for an extended amount of time, leading to negative effects due to the cortisol release. High amounts of cortisol decreases immunity, and breaks down muscle bone and connective tissue. A goal for Mrs. Crane would be to lower her stress levels in order to better her health.

The 2008 Tibetan Unrest Research Paper Example | Topics and Well Written Essays - 2750 words

The 2008 Tibetan Unrest - Research Paper Example In 2008 during the eve of the Olympics, there was a series of unrest in Tibet (Merkel-Hess, Kate, Kenneth and Jeffrey54-55). During the same period, there was so much focus on Beijing. Tibet is a part of Beijing’s claimed territory (Goldstein 450). In March 14th, there were a succession of demonstrations, protests and riots ain the Tibetan capital of Lhasa. The unrest commenced on the 10th of March during the 49th commemoration of the abortive uprising in Tibet in 1959 in opposition of Beijing rule. The demonstrations spread over to several areas and various monasteries outside of Tibet. The unrest commenced with numerous monks from Drepung monastery staging peaceful protests. The monks were demanding the release of their fellow counterparts arrested in the previous autumn. The participants of the unrest direct their anguish to two civilians named Han and Wei. In the break of one weak, serious protests began marred with violence. There was widespread looting, killing, burning and rioting. Media reports found that this unrest was due to the socio-economic issues in Lhasa (Losada 340). The people of Tibet were infuriated by the high rates of inflation that resulted in the increase in prices of consumer goods and food (Goldstein 454-500). The youth were also complaining of inequality in access to jobs and education. James miles, a reporter of â€Å"The Economist†, termed the 3.14 riot as an eruption of tribal hatred. The rest of this paper will focus on Tibet’s struggle for sovereignty, the religious power and politics of the Tibet territory and the underlying causes of the event. Truth about the riots; the facts At the core of the conflict is a conflicting perspective on who is the rightful owner Tibet. In the early 1800s, China viewed Tibet as a vassal state that paid tribute to the emperor through a priest-patron relationship. In recent times, the relationship has become ambiguous. China suffered in the hands of the British during the same period when the British conquered Lhasa in 1904 (Merkel-Hess, Kate, Kenneth and Jeffrey 59). China has since struggled for the full claim of Tibet hence the delicate relationship between the two. The question of who ought to take blame for the 2008 unrest is therefore relative given both parties legitimise their clemency to Tibet. What really transpired during the killings? There has been little if any condemnation of the killings in Tibet by the western countries. Statements were made about the infringement of human rights by the People’s Republic of China overshadowing the real tribulations of the victims of the violence. The reality of the issue is that there were killings and destruction of property even from some of the reports by western media only that there was no attention paid to the magnitude of the killings. The unrest had a series of serious criminal activities including looting, beating, destruction of property and arson. The rioters set fire on more than three hundred places that include hospitals, schools, shops, houses of civilians and government offices. In addition, about 214 rooms burned down and another 56 vehicles torched. There were very brutal killings with an estimated 31 innocent people slashed or burnt to death (Merkel-Hess, Kate, Kenneth and Jeffrey 63). Another 51 police officers were injured with 12 of them suffering serious injuries. As such, the riot was

Management Essay Example | Topics and Well Written Essays - 750 words - 1

Management - Essay Example The way in which this change was planned and implemented resembled the approaches to organizational change set out by Hughes, Ginnett, and Curphy in their book, Leadership: Enhancing the Lessons of Experience. The first step was the initiation and the planning stage where the change was considered important as well as setting out of various goals and identifying the necessary resources that will help in meeting the set out goals. The second stage was the momentum stage where the resources were directed together with the use of the experienced individuals in the organization who directed the change. The new values were developed together with attitudes and conduct of various stakeholders through internalization. This stage also involved education of the members of staff to integrate the new changes in the system, while other major changes involved the reshuffling of jobs and duties to enable the smooth running of the organization. The final stage in the change process entailed the sta bilizing of the change through the change in the organization’s culture and norms. ... The leaders were able to deal with various complexities that arose in the process of bringing change. These leaders incorporated the help of other stakeholders in formulating policies and clear visions and through this commitment were obtained. Every stakeholder was involved through co-creation, delegation and empowerment and the leaders were able to express their trust in the abilities of their employees and dealt with them with compassion and laid emphasis on the need for continued learning in order to improve the understanding of the new system thus creating efficiency (Hughes, Ginnett & Curphy, 2009). The change process within the institution coincided with Kotter’s eight step process for implementing change within an organization. The institution was able to ascertain a sense of urgency that required the initiation of change. The leaders realized that the introduction of ICT in the organization would improve the efficiency and the overall output thus there was urgency in implementing change thus this prompted the leaders to identify individuals with the right skills in the ICT sector to help in effecting the change needed. The leaders were able to develop the vision together with the strategy that would help the stakeholders in committing themselves towards the achievement of the specified goal. A new channel through which information would be passed to the right people was created and various barriers were eliminated through the empowerment process as well as rewarding people who contributed to the change. This strategy of rewarding people acted as the motivating factor and prompted people to work harder. As the rewarding of people took

Microbiology Work Essay Example | Topics and Well Written Essays - 1000 words

Microbiology Work - Essay Example They also contribute to patient’s treatment as well as the control of infection in the community and hospitals. However, Microbiology is rapidly changing. In the late 1970s, HIV and AIDS were unknown, but by the year 2000, approximately 22 million HIV related deaths had occurred globally. Ebola and Legionnaires viruses were also unknown, but a year later, they were making headlines. Microbiologists decided to go to the laboratory to find the virus behind AIDS and other diseases. The laboratory categorized the samples and dealt with each sections of the virus depending on the site and nature of collection. In this regard, this paper aims at explaining microbiology work in HIV, identifying the problems or issues that face scientists today as well as identify science influence or contribution to today’s culture in terms of technology, advances, and infectious disease controls (Gustavo, 2001). HIV/AIDS is said to have spread rapidly. There are roughly 33.4 million people li ving with the virus, 2 million deaths from and 2.7 new infections of AIDS. Microbiologists discovered that HIV virus causes AIDS (Acquired Immune Deficiency Syndrome). The virus is said to infect cells which are critical to the immune system, and as a result, destroy the ability of the system to fight infections. Therefore, it was found out that people who have AIDS do not have the ability to fight infections by other bacteria and viruses, which cause diseases in healthy people. Because of this, AIDS patients die from such infections that the scientists regard as harmless. Some of them develop cancers in their systems (Basic information about HIV and AIDS, 1999). The Microbiologists first discovered the agent which causes AIDS in 1983. In about 24 years, there were abnormal infection clusters that were found in homosexual men and approximately a million of Americans have contracted HIV. This epidemic has now afflicted both female and males in all ethnic groups. Spencer and Ragout (2 004) claim that, scientists acknowledge that the epidemic is growing rapidly among women and minority population. There are over 20 million deaths and the epidemic is spreading in all geographic regions. However, there is hope in finding the cure for AIDS because, Microbiologists are doing all they can to discover it. They have managed to stabilize it because of the ARVs that they initially discovered for its control which has helped in avoiding deaths. To add to this, they claim that when a person becomes infected with the HIV virus, there is a substantial lag time, for example, a decade before the person fully develops the AIDS symptoms, although the anti-HIV drugs can help delay the symptoms. However, afterwards, infected individuals start experiencing symptoms of Flu and are said to go for many years without the symptoms being detected (Basic information about HIV and AIDS, 1999). During this phase, the virus is said to continue replicating within the body, in addition to transm itting to other individuals if there is a direct contact with body fluids such as blood and semen. This time there is a steady but slow depletion of the cells, known as CD4 positive T cells which are infected by HIV. A Microbiologist found out that a normal person usually has 1000 CD4 Tcells in a blood milliliter, which HIV infects, and once the cells fall to 200 cells the person infected enters another phase which is now called AIDS.

Managerial Economics Essay Example | Topics and Well Written Essays - 250 words

Managerial Economics - Essay Example From this study it is clear that  accounting profit is the surplus money gained by the firm after deducting explicit costs such as labour from the total amount of revenue generated from its operations.   On the other hand, the difference between the firm’s accounting profit and implicit as well as explicit costs is known as economic profit. It is important for the managers to understand the difference between accounting and economic profits. Accounting profit denotes the firm’s market value to establish if it is operating viably. On the other hand, economic profit denotes if the firm’s economic condition is sound enough to continue with operations or halt them. It should be positive for a firm to carry own with operations.  This paper outlines that the majority of for profit firms are in business to generate profits from their operations. As such, the best way to measure a firm’s performance is to determine its current level of profitability compared to its previous profits for the same period. An increase in profits compared to the previous period entails that the firm is performing well while a decline in profits means that its performance is below expected standards since firms are mainly concerned with generating profits from their operations.     The major types of profits include accounting and economic profits as outlined in the prompt below.  Basically, accounting profit is the surplus money gained by the firm after deducting explicit costs such as labour from the total amount of revenue generated from its operations.  

Organisations Essay Example | Topics and Well Written Essays - 1500 words

Organisations - Essay Example This paper primarily deals with the responsibility of the multi national giant Unilever's responsibility to its stakeholders. It also identifies who the stake holders are and the ethical issues involved in relation to the benchmarks and models set up by the CSR. The Stakeholder: The Merriam Webster online dictionary defines a stake holder as "a person entrusted with the stakes of bettors" and "one that has a stake in an enterprise ". This definition takes the traditional view of the term stake holder. Another definition form the site Encarta defines stakeholder as "a person or group with a direct interest, involvement, or investment in something, e.g. the employees, stockholders, and customers of a business concern". From a legal standpoint too, stakeholder is considered to be a person holding shares or stocks in a company. All these definitions agree on one point, but disagree on others, making the issue confusing. Since this paper deals with Unilever, an analysis as to what the company thinks of the definition will be worth looking into. Unilever categorises stake holders into two groups, the first one to include all those who have direct contact with the company. They include investors, employees, customers and suppliers. The other group comprise of those who have an indirect relationship with Unilever and include the government and its various regulatory departments, non profit organisations, academics and citizens. "Our success as a company depends on good relationships with a broad range of people and organisations who have a stake in our business. With some, such as our customers, employees, suppliers and investors, the relationship is based on direct contact or financial involvement with the business. Others, such as governments and regulators, local communities, civil society organisations, academics and individual concerned citizens, have a wider interest in what we do and in our impacts on society as a whole." (Our approach, 2008). The Stakeholders of Unilever: Customers: Unilever considers its customers to be stakeholders of the company. How customers can be considered a stakeholder can be illustrated by the following point. Unilever uses chemicals in the manufacture of its detergent brands like surf and sunlight. The company cannot use cheaper, but harmful chemicals with the aim of increasing its bottom-line. The company has a social responsibility to see that none of its customers who use the detergent have problems for their skins or clothes. Employees: The livelihood of its employees depends on the ability of the company to pay them their salaries. The company has to remain profitable to sustain this practice. So Unilever has a responsibility to see that its operations remain profitable. Suppliers: For a company like Unilever, there would be a large number of suppliers responsible for the supply of the variety of raw materials, services and other products required for manufacturing and administration. They have to be paid according to the conditions stipulated and it's the company's responsibility to see that it is done. Investors: this category, as a stakeholder does not need clarification since it falls into the traditional and legal view of the term stakeholder. Any company has to ensure that their stakeholders, which include individuals and institutions, are kept happy by ensuring a favorable return on their

Writer's choice- Recommendation Essay Example | Topics and Well Written Essays - 250 words

Writer's choice- Recommendation - Essay Example The book recognizes the fact that client satisfaction is an imperative factor that determines a firm’s profit margin. Essentially, the book establishes a foundation upon  which ethical financial management practices can be based. Moreover, the reader gets a gist of legal repercussions that might be associated with unethical practices while offering services to clients. I found the book helpful in my law practice since it provides valuable information that outline ethical behavior characteristics and the various legal actions that may be adopted to protect the clients’ interest. However, the book has some various flaws that make it difficult to rely on it alone. For instance, the book does not provide a comprehensive legal process that can be followed by clients in case of unethical practices by service providers. I wish the book addressed more on the approaches to be followed to restore ethics in the money industry. In addition, the book should have talked more of planning since the money business has grown quite dynamic. In summary, the book provides useful concepts but has been very narrow-focused as it focuses one similar

Essay 1 Example | Topics and Well Written Essays - 750 words - 18

1 - Essay Example Le Roman de Silence is story told by an anonymous author from the 13th Century Medieval times. It is a story about a protagonist who is naturally a female, but is trained by his parents to act like a man. The main reason that her parents decide to raise silence as a boy is to retain their wealth for their daughter, because according to law of the day there was no inheritance right for the women. Therefore, Silence is made to learn the crafts of a ministerial, and develop skills that would lead her to knighthood (de Cornuà ¤lle & Thorpe, 1972). At the age of twelve, the time of puberty, Silence has to decide, whether she should stick to the choice of her parents or accept what the nature has made her. At this point in time she comes across Dame Nature and Dame Nurture (de Cornuà ¤lle & Thorpe, 1972). She decides to stick with the choice of her parents, and invest her energies in becoming a respected male figure. Society is an important determinant in the development of human personality. Like nature it applies certain selection pressures that transform, rather modify the way a person thinks and make decisions. The involvement of social pressure is quite evident in the case of Silence’s choice to be a man (Bloch, 81-99). Assigning gender roles is an important element in inducing specific mentality into individuals belonging to a particular gender. There are several characteristics in males that are either different or completely absent in the females. For instance men are impatient, while women have patience; men are less emotional compared to women; Men are more aggressive than women, and so on and so forth. Silence is shown to be overwhelmed by the masculine characteristics that she gives up on her biology, and pretends to spend her days like a man. Apart from the natural differences between the two genders, there are several artificial features that are used as clichà © to separat e the two genders. Application of gender roles is nothing

Endothelial tight junction proteins Essay Example for Free

Endothelial tight junction proteins Essay Endothelial tight junction proteins Introduction            The endothelium is situated at the inner side of all kinds of vessels and comprises of a monolayer of endothelial cells. Inter-endothelial junctions comprise junctional complexes, such as adherens junctions (AJ), tight junctions (TJ) and gap junctions (GJ) that play essential roles in tissue integrity, barrier function and intercellular communication respectively. These junctional complexes are related to those found at epithelial junctions with notable changes in terms of certain molecules and structure.            Endothelial junctional proteins play important roles in tissue integrity but also in vascular permeability, leukocyte extravasation and angiogenesis. Dormant endothelium may be exposed to stimuli provoking leukocyte extravasation at seditious sites and propagating angiogenesis. Both activities have an intense impact on endothelial cell-cell junctions.            Tight junctions aid the major functional objective of establishing a barrier inside the membrane, by controlling paracellular permeability and sustaining cell polarity. They achieve this by constricting apical or basolateral transmembrane diffusion of lipids and they have been suggested to contribute in regulating proliferation and differentiation of epithelial cells. However, the components that are involved and the signal routes concerned are unknown (Mitic Anderson 1998).            Tight junctions are made up of integral membrane proteins claudins, occludin, tricellulin, junctional adhesion molecules (JAMs), including many peripheral membrane proteins such as the scaffold PDZ- domain proteins. This review will however, focus on ZO-1 and ZONAB. Histology of endothelia junctions            The junctional structures situated at the endothelial intercellular fissure are related to those located at the epithelium; however, their formation is more inconsistent and in most vascular beds their topology is less constrained than in epithelial cells. Adherens junctions, tight junctions and gap junctions are in most cases intermingled and create a complex zonular system with disparities in depth and thickness of the sub-membrane plate associated with the junctional structure (Franke et al. 1988; Rhodin 1974). In contrast to epithelial cells, GJs are often found close to the luminal surface. Hence, the term â€Å"Apical junction† used to jointly describe epithelial TJ and AJ may not be applied to the endothelium. The endothelium forms the vascular barrier with controlled permeability properties between the blood and the underlying tissues.            Tight junctions exhibit considerable inconsistency among different segments of the vascular tree (Franke et al. 1988). This disparity composes a major evidence of vascular bed differentiation of endothelial cells and has a strong impact on vascular permeability and leukocyte extravasation. Variations concern the complexity degree of the occluding strands as well as tight junction composition.            Large Artery endothelial cells, which are exposed to high flow rates, display a well-developed system of tight junctions. Within the microvasculature, tight junctions are less complex in capillaries than in arterioles, and even less in venules. It is important to mention that, post-capillary venules are the primary site of leukocyte extravasation, and accordingly, they display a high content of permeability mediator receptors, such as those for histamine, serotonin and bradykinin. On the other hand, blood brain barrier (BBB) and the blood retinal barrier (BRB) are predominantly rich in Tight Junctions and endothelial tight junctions have been principally studied in these sites.            Endothelial intercellular realms differ from those of epithelial cells by the absence of desmosomes (Franke et al. 1988). The transitional filaments, comprised in the endothelium by vimentin molecules, are poorly connected to cell-cell contacts. However, contrary to the situation in epithelia, the vimentin filaments may be associated to endothelial adherens junctions in junctional structures similar to desmosomes, called complexus adherens.            It must be emphasized that interendothelial junctions are vibrant structures, subjected to multiple regulations. Moreover, leukocytes extravasate majorly in postcapillary venules either through transcellular or paracellular methods. Extravasation via the intercellular junction is a rapid and controlled process, through which the leukocyte is squeezed in the fissure (diapedesis), followed by rapid junction reformation.            ZO-1 is a protein located on the cytoplasmic membrane plate of intercellular tight junctions and is engaged in transducing signals at cell-to-cell junctions. ZO-1 links tight junction transmembrane proteins to a cytoplasmic plaque and the actin-based cytoskeleton (Aijaz et al. 2006; Tsukita et al. 2001). In epithelial cells, ZO-1 interrelates with the transcription factor ZONAB to regulate cells proliferation in a cell density related manner (Balda Matter 2000); however, the functions of ZO-1 and ZONAB in endothelial cells are still not clearly understood.            Unpublished work shows that downregulation of ZO-1 in endothelial cells stimulates redistribution of two transmembrane proteins; claudin-5 and JAM-A, and radical changes in the cytoskeleton affecting the localization of mechanosensor proteins and VE-cadherin role in the control of cell-cell tension.            These observations imply that one function of ZO-1 in endothelial cells is to coordinate components of the tight junction and associate them to the cortical cytoskeleton. However, it is unfamiliar whether the ZO-1 associated transcription factor ZONAB is linked to such ZO-1 effects.            Despite the fact that, ZO-1 explicitly associates with epithelial tight junctions (Stevenson et al. 1986), it has been observed that the protein appears in the nucleus in the process of proliferation (Gottardi et al. 1996). While the functional impact of the nuclear localization is currently not clear, studies reveal that these discrete subcellular distributions of ZO-1 are exquisitely sensitive to the state of cell-to-cell contact.            ZO-1 plays a major role of restraining ZONAB and regulates its accumulation in the nucleus through cytoplasmic sequestration. MDCK cells found in the epithelium exhibit two forms of this Y-box transcription factor (ZONAB) i.e. ZONAB -A and ZONAB -B which vary in a 68-amino acid supplement. Both categories of ZONAB bind to ZO-1 and link with intercellular junctions (Balda Matter 2000).            ZONAB was initially designated in canine kidney epithelial cells (MDCK) and is a Y-box transcription factor. Y-box transcription factors are multipurpose control mechanisms of gene expression and studies suggest that they play a common role in enhancing proliferation (Bargou et al. 1997). ZONAB is one of the tight junction-associated dual localization protein: it localizes to junctions where it attaches to the SH3 surface of the adaptor protein ZO-1, and to the nucleus where it regulates transcription.            The distribution of ZONAB is controlled by the cell density as it localizes to both junctions and nuclei in low density, proliferating cells, and becomes constrained to the cytoplasm in high density cells (Balda Matter, 2000). This distribution is also exhibited in its transcription activity, as ZONAB is transcriptionally vigorous in proliferating cells but inactive in non-proliferating cells. In the MDCK cells, ZONAB is necessary for normal rates of proliferation and controls G1/S phase transition (Balda et al. 2003).            ZONAB affects cell cycle development by two distinct processes: it controls the nuclear accumulation of CDK4 through a direct interaction and controls manifestation of genes encoding cell cycle regulators for example, PCNA and cyclin D1 (Balda et al. 2003; Sourisseau et al. 2006 ).            In 3D principles of MDCK cells, regular ZO-1 and ZONAB processes are necessary for epithelial cyst formation, implying that the Y-box transcription factor also controls epithelial differentiation (Sourisseau et al. 2006). Since ZO-1 and ZONAB can also relate with other types of intercellular junctions, for instance the gap junctions, in cells that lack tight junctions, it is possible that ZO-1 or ZONAB signaling is also of useful significance in other cell types other than epithelia (Ciolofan et al. 2006; Giepmans Moolenaar 1998). Aims of the study            The aim of the study is to understand the functional consequences of downregulation of ZONAB in endothelial cells, and whether and how ZONAB cross-talks with other junctional components to regulate endothelial cell migration, proliferation and angiogenesis. Currently, we are looking at similarities and differences between the phenotype of downregulation of ZO-1 or ZONAB by RNA interference. Changes in expression and localization of a given protein are analysed using specific antibodies for immunoblots and immunofluorescence. Preliminary Results            It is observed that downregulation of ZO-1 or ZONAB resulted in similar redistribution of actin and vinculin from cell-cell junctions to stress fibers and focal adhesions, respectively. However, the localization of transmembrane proteins such as Claudin-5 and JAM-A is affected by downregulation of ZO-1 rather than by downregulation of ZONAB. The localization of the polarity protein PAR-3 is changed in both conditions.            Additionally, downregulation of ZONAB causes changes in ZO-1 by immunofluorescence that needs to be tested for expression by immunoblots. Next, we will characterize other transmembrane proteins (e.g. MD3 and claudin-1), polarity proteins (PKCzeta), Rho regulators and mechanotransducers such as PAK2, Zyxin and YAP.            ZONAB is a DNA and RNA binding factor that it is involved in transcription (e.g. cyclin D1 and PCNA) in the nucleus and translation (e.g. cell cycle inhibitor p21) in the cytosol. Thus, we are also trying to identify new genes regulated. We have identified that expression of fibronectin is regulated by ZONAB. We are evaluating whether the changes in protein expression of fibronectin are due to ZONAB role on transcription or translation, using actinomicin D to inhibit transcription or cyclohexidimide to inhibit translation. Additionally, we are validating new genes identified by cDNA array analysis of endothelial cells with downregulation of ZONAB.            The tight junction localizing protein ZO-1 symptomatically forms a continuous band around the apices of well-differentiated, confluent, polarized epithelial cells in culture. However, under nonconfluent conditions, endogenous ZO-1 can localize to the nucleus in addition to the border of cell-cell contact.            ZONAB manifestation tends to be high in proliferating but low in growth-impeded MDCK cells, implying that high manifestation levels might be a necessity for cell proliferation (Balda Matter 2000).            ZONAB confines in the nucleus as well as tight junctions in proliferating cells, however, it is not noticeable in the nucleus of nonproliferating high density cells (Balda Matter 2000), proposing that accumulation of ZONAB in the nucleus might be necessary for efficient proliferation.            ZO-1 quantities are low in proliferating cells and they rise with cell density, and overexpression of ZO-1 hinders accumulation of ZONAB in the nucleus (Balda Matter 2000); hence, ZO-1 may control proliferation by inhibiting ZONAB from accumulating in the nucleus. Overexpression of ZO-1 in low density cells triggers a redistribution of ZONAB from the nucleus to the cytoplasm and reduced proliferation.            CDK4 is a major regulator of G1/s transition (Sherr 2000; Malumbres Barbacid 2001). Thus, ZONAB could control proliferation by regulating the process or the localization of CDK4. Since ZONAB binds CDK4, the nuclear pools of the two proteins may diminish in a parallel manner.            Symplekin is combined with ZONAB in the nucleus; hence, it could be argued that Symplekin modulates the transcription activity of ZONAB. Increased expression of Symplekin results in stimulation of the transcriptional suppressor ZONAB. However, it is also noted that Symplekin is absent in endothelial cells (Keon et al. 1996).            ZONAB controls cell cycle entry. ZO-1 overexpression results in a reduction in DNA synthesis, implying that entry into S-phase was distressed.            These experiments will allow understanding the role of ZO-1 and ZONAB in endothelial cells. Depending on the results, we plan to test how these two proteins are involved in endothelial stress conditions such as shear stress and high glucose. Conclusion            The collaboration of ZO-1 with tight junctions can only be significant for the stabilization of ZO-1, as opposed to attaching ZO-1 to the plasma membrane so as to constrain nuclear accumulation of related proteins. This is supported by the opinion that a truncated protein comprising only the HA-tagged SH3 domain accumulated in the Cytosol, but was adequate to decrease proliferation and nuclear accumulation of ZONAB (unpublished data).            ZONAB and ZO-1 control proliferation and the ultimate cell density of MDCK cells. Explanations that ZO-1 accumulates with increasing cell density, and overexpression of ZO-1 in transfected cells lowers the final density proposes a pattern in which ZO-1 serves as a measure for cell density whereby, on reaching the threshold level, provokes growth impediment by cytoplasmic sequestration of ZONAB and the related cell cycle kinase CDK4. It will be essential to control how the ZO-1 or ZONAB pathway associates with the other signaling methods that affect proliferation.            Vascular endothelial stress induces dysfunctions that have been implicated in many diseases such as diabetes and diabetic retinopathy. Therefore, characterization of the role of tight junction molecules in different endothelial cell behavior and functions will help us to understand the molecular mechanisms of disease pathogenesis and these findings may be implicated in prognosis and possibly to develop new treatment strategies. References Balda, MS and Matter, K 2000. The tight junction protein ZO-1 and an interacting transcription factor regulate ErbB-2 expression. EMBO J. 19, pp 2024-2033. Balda MS, Garrett MD and Matter K, 2003. The ZO-1 associated Y-box factor ZONAB regulates epithelial cell proliferation and cell density. J. Cell Biol. 160, pp 423-432. Bargou RC, K Jurchott, C Wagener, S Bergmann, S metzner, K Bommert, MY Mapara, KJ Winzer. M Dietel, B Dorken, and HD Royer, 1997. Nuclear localization and increased levels of transcription factor YB-1 in primary human breast cancers are associated with intrinsic MDR1 gene expression. Nat. Med. 3: pp 447-450. Ciolofan C, Li XB, Olson C, Kamasawa N, Gebhardt BR, Yasumura T, Morita M, Rash JE and Nagy JI, 2006. Association of connexin36 and Zonula occludens-1 with zonula occludens-2 and the transcription factor zonula occludens-1 associated nucleic acid-binding protein at neuronal gap junctions in rodent retina. Neuroscience 140: pp 433-451. Franke WW, P Cowin, C Grund, C Kuhn, HP Kapprell, 1998, The Endothelial Junction: the plaque and its component., in: N. Simionescu, M Simionescu (Eds.), Endothelial cell biology in health and diseases, Plenum publishing corporation, New York. pp 147-166. Giepmans BN and Moolenaar WH, 1998. The gap junction protein connexin43 interacts with the second PDZ domain of the zonal occludens-1 protein. Curr. Biol. 8. Pp 931-934. Gottardi CJ, M Arpin, AS Fanning and D Louvard, 1996. The junction-associated protein, zonular occludens-1, localizes to the nucleus before the maturation and during the remodeling of cell-cell contacts. Proc. Natl. Acad. Sci. USA. 93: pp 10779-10784. Keon BH, S Schafer, C Kuhn, C Grund, WW Franke, Symplekin, a novel type of tight junction plaque protein, J Cell Biol. 134 (1996) 1003-1018.Malumbres M and M Barbacid, 2001. To cycle or not to cycle: a critical decision in cancer. Nat. Rev. Cancer. 1: pp 222-231. Mitic LL and JM Anderson, 1998. Molecular architecture of tight junctions. Annu. Rev. Physiol. 60: pp 121-142. Rhodin, JAG 1974, Histology, Oxford University Press, New York. Sherr, CJ 2000. The Pezcoller lecture: cancer cell cycles revisited. Cancer res. 60: pp 3689-3695. Sourisseau T, Georgiadis A, Tsapara A, Ali RR, Pestell RG, Matter K and Balda MS, 2006. Regulation of PCNA and cyclin D1 expression and epithelial morphogenesis by the ZO-1 regulated transcription factor ZONAB/DbpA. Mol. Cell. Biol. 26, pp 2387-2398.Stevenson, BR, JD Siliciano, MS Mooseker, and DA Goodenough, 1986. Identification of ZO-1: a high molecular weight polypeptide associated with the tight junction (zonula occludens) in a variety of epithelia. J. Cell Biol. 103: pp 755-766. Source document

Education Essay Example for Free

Education Essay As I reflect on the knowledge I have attained in this Educational Psychology course, I feel confident enough to say that I have learned an immense amount of information that I believe will be beneficial in my future classroom. In addition, some of the information that we have covered as a class was information that I had previously learned while at the University of Guam. I greatly appreciate the amount of knowledge I have attained in this course, and I would like to focus my reflection on three main topics: long-term memory; the cognitive process of attention, perception, encoding, and retrieval; and the four theories of motivation (behaviorist, cognitive and social cognitive, sociocultural, and humanistic). These are just three of many learning experiences that I believe will play an important role in my future career. I decided to focus on long-term memory because this type of memory plays an important role in each of our minds. According to Eggen and Kauchak (2010), long-term memory is the permanent information store in the model of human memory. What a child learns at a young age will most likely be kept in his or her long-term memory until further notice. In my experience while in this ED 300 class, several of the topics that we have discussed has brought up information from my long-term memory; thus I was able to further comprehend such topics. I was able to retrieve specific information based on what I had learned previously. Being able to retrieve information gives me an â€Å"aha!† moment in which I felt confident in answering questions and further discussing such topics with my peers. Retrieving information is just one of four steps in the cognitive process. Throughout the semester I have tried to focus on the four steps of the cognitive process (attention, perception, encoding, and retrieval) with my studies. As a college student, I have had my days where it was hard for me to even pay attention to the class lecture. However, after taking the time to reflect on what I have learned in this course, we practice the four steps of the cognitive process each day. The lecture is compatible to the first step of attention; perception is understanding the information; encoding is similar to memorizing the information; and retrieval is compatible to the reflections we each share at the end of the class. Finally, what I believe to be the most important topic that I have learned from this course are the different types of theories of motivation. As a human being there is more than one type of influence that motivate us to behave the way we do. From this Educational Psychology course, I have learned about the different theories of motivation, each of its meanings, and relating it to my own life. After learning about the different theories of motivation, I took into account my behaviors and where these behaviors originated from. Furthermore, I took into account the amount of motivation that it has given me. For example, as a Chamorro it is an old custom that women are to take care of the household. However, I was motivated by my mother to study hard and to make my dreams come true; and I believe that some outside influence had motivated her to break this old Chamorro custom. In conclusion, I believe that I have learned an immense amount of information throughout this semester. I have taken the time to reflect on the amount of knowledge we have shared in the classroom. I have taken into account the opinions of others; and I have reflected on the different types of motivations that have influenced me in my twenty-one years of life. I hope to one day be able to retrieve the information that I have learned in this course and apply such knowledge and theories in my future classroom.