Friday, September 6, 2019
The most persuasive of three models of attorney-client relationship Essay Example for Free
The most persuasive of three models of attorney-client relationship Essay While in the attorney-client relationship, lawyers face three obligations in performance.à First, they must assume the duty of fully investigating a clientââ¬â¢s case. à Lawyers should seek out all relevant acts.à This information is necessary to provide the client with an effective counsel.à The second duty is zealous client advocacy. These duties are sometimes at odds with the third duty which is the obligation of lawyers to the court.à All active lawyers are officers of the court and therefore, hold certain responsibilities. à à à à à à à à à à à It has been argued that only two of the above three obligations can be met at any given time.à à Dean Freeman is quoted as saying, ââ¬Å"To convert the defendantââ¬â¢s only champion into yet another member of the stateââ¬â¢s legions seems an unnecessary and offensive step.â⬠à à à à à à à à à à à The first and second obligations are in place to insure zealous advocacy; and the third is essential for lawyers to participate in the judicial system as it is designed. (Retrieved on 11/17/06 from source: http://www.findarticles.com/p/articles/mi_qa3975/is_200207/ai_n9119407) à à à à à à à à à à à The ABA has promulgated three model codes of lawyers since 1908.à The Canons of Ethics in 1908 was first.à This established many rules and codes that are still in effect today.à One thing the Canons did was to ban lawyers from advertising, except in the case of handing out business cards. à à à à à à à à à à à The Canons were the ABAââ¬â¢s direct response to President Rooseveltââ¬â¢s 1905 criticism of lawyers as ââ¬Å"hired Cunningâ⬠, or, those who, for lucrative fees, undermined the public interest by their representation of corporation and wealthy individuals.à These Cannons were adopted and were the legal professionââ¬â¢s authoritative statement of how a lawyer should act. (Retrieved on 11/17/06 from source: www.bryancave.com) à à à à à à à à à à à à The 1908 Canons included the duty of an attorney to keep a clientââ¬â¢s secrets. This element of confidentiality is the duty I hold most important.à The Canons of 1908 set the premise of trust in the minds of the general, lawyer seeking public.à Attorneys can be more persuasive to their clients in regards to gaining their trust, if the client knows their secrets will be kept and confidentiality is firmly in place. à à à à à à à à à à à à The American Bar Association Model Code of Professional Responsibility was created in 1969.à This was a set of professional standards intended to guarantee the minimum legal ethics and responsibility of lawyers in the U.S.à It was ultimately replaced with the Model Rules of Professional Conduct after the Watergate scandal. à à à à à à à à à à à While I do feel all three model codes are important, the Canons are most persuasive in my book as they lay a firm base for what is expected from todayââ¬â¢s lawyers:à Confidentiality, competence, honesty, loyalty and clientââ¬â¢s access to progress through exchange of information. (Retrieved on 11/17/06 from source: www.dcbar.org)
Thursday, September 5, 2019
Chronic Fatigue Syndrome Health And Social Care Essay
Chronic Fatigue Syndrome Health And Social Care Essay Chronic Fatigue Syndrome (CFS) is an incapacitating multifarious disorder that renders the victim fatigued for longer periods. It has been realized that this kind of disorder is not solved by bed rest and is usually aggravated by mental and physical activities. People suffering from CFS have been seen to be unable to perform tasks that they were to do it comfortably before the illness. The most noticeable features of this disorder include pain in the muscle, weakness, impaired memory, and poor concentration. In addition, the victims are generally weak and some of them show evidences of insomnia (Bell, 1995). This disorder may persist for a long period. Diagnostic tests have not been able to clearly point out the possible causes of this disorder. This is because of the fact that some illnesses have symptoms related to this disorder and we cannot confine those symptoms to this particular disorder alone (Verrillo, Gellman, 1988). Any infection to the immune system taken to be the possi ble cause of CFS and microorganism play a major role in causing it. Any form of immune-suppression is also seen a factor that compromises an individual to this disorder (Fisher et al 1997). Introduction Absence of specific diagnostic characteristic features of CFS, a criterion has been formulated that helps physicians in detecting the disorder. One of the most commonly used criteria is the one that requires the victim to show the possible symptoms for a period of more than six months. This is because the physician will have had enough time to diagnose other possible ailments and thereby reaching the point of excluding the disorder much easily (Murdoch Denz-Penhey, 2002). Additionally, the patient is expected to show any of the four symptoms, which may include frequently occurring sore throat, muscle pain, impairment of the patient to the extent of affecting the normal economic activities of the patient and unrefreshing sleep (Lisman Dougherty, 2007). Other symptoms that can be used include pain in all the joints of the body, severe headache that recurs in some pattern, and post-exertional depression. The purpose of this study is to find out some of the predisposing factors for thi s disorder. Additionally, the causes, symptoms, ways of diagnosing this disease will be identified (Moss-Morris Petrie, 2000). Suggested treatments will be provided so that the healthy population can know more on how to avoid this disorder. Various studies have been carried with the intention of trying to find ways of finding definite symptoms for this disorder. One of these studies was carried out in 1993 with the intention of improving on the ways of diagnosing the disease as it had been decided earlier in 1988. The aim of the study in 1993 was to reinvent new strategies of that can lead to faster diagnosis of the disorder (Lisman Dougherty, 2007). Some of the recommendations from the researches at that time was to classify the fatigue to different levels as can be depicted by the victims. Those with less than six months infection for instance were classified as having chronic fatigue while those with more than six months symptoms were classified as having relapsing fatigue. The patients could also be classified as having gradual or sudden fatigue, among other distinguishing parameters (Fisher et al 1997). A number of predisposing factors have been identified as it regards to CFS. It is also important to note the greater portion of the American population have similar symptoms related to this disorder but cannot be classified as CFS (Meirleir Patarca-Montero, 2000). Some of the factors that promote the risks of having the disorder include age, gender, and socioeconomic groups. It has been found that CFS affects women at a higher rate four times than men (Voncannon, 2002). In addition, individuals with the age between 40 to 50 years have been found to be having CFS. It is also important to note that children can be found with the disorder especially in their teen years and this show that the disease affects any age (Fisher et al 1997). Some of the important symptoms for CFS include prolonged fatigue that extends to a period over six months. Such a fatigue is not reduced by any amount of rest. Other notable characteristics of this disorder include post-exertional disquiet, pain in the muscles, pain in the multiple joints, lack of concentration, sleep that does not refresh, and headache that comes with some pattern (Englebienne, 2002). Additionally, the throat the regularly becomes sore and presence swellings in the lymph, chronic cough, nausea, weight loss, skin sensations, and jaw pain. Psychological problems, shortness of breath, and chest pain are also important symptoms of the disease (Moss-Morris Petrie, 2000). A number of factors makes it hard for physicians to diagnose CFS and includes the lack of laboratory diagnostic technique or biomarkers. Other reasons include the fact that fatigue is a common symptom for all other illnesses, patients do not look sick while the pattern of illness is not constant. This has led to the low level of diagnosis for this particular disorder. Exclusion technique is the best method to diagnose CFs disorder due to lack blood tests or scans for the brain (Leonard, 1997). Diagnosis has to be carried out for period extending six months where the patient can report sufficient evidence of being constantly tired. The physician has to take enough history of the illness of the patient who may be suspected of having CFS (Royal College of Physicians of London, 1997). Medical history has to be reviewed also in order to identify and rule out the possible illnesses that might have been the cause of the fatigue. This is done until CFS is ultimately pointed out. The physicia n can later develop a treatment for the patient. It is also possible for patients to diagnose themselves by eliminating the possible causes of the illnesses just like physician (Englebienne, 2002). The process of managing the chronic CFS is very tricky just like the diagnosis itself because of the variety of the symptoms. Currently, there is no drug or cure for this disorder and such factors complicate the treatment process (Demitrack Abbey, 1999). This means that the best way of managing it by developing an individualized treatment plan for every patient. The best plan comprises a collection of therapies each aimed at managing the symptoms shown by the patient. Input by range medical professional experts is the best solution and when this is coupled with the treatment of other illnesses then the disorder can be managed easily (Lisman Dougherty, 2007). Living with CFS is very tricky and having the chronic type can result in significant devastating effects on the victim. Some of the challenges facing the success of treating CFS include the change and predictability of the symptoms, variations in the stamina that interferes with someone elseà ¢Ã ¢Ã¢â¬Å¡Ã ¬Ã ¢Ã¢â¬Å¾Ã ¢s a ctivities, altered memory, loss of independence, and potential impacts on decreased sexual activities among couples (Bell, 1995). Some of the treatment options that is available for CFS and they include professional counseling, cognitive behavioral therapy, and symptomatic treatment. Additionally, pharmacologic therapy, sleep hygiene, pain therapy, and use of antidepressants can help in suppressing the effects of CFS (Demitrack Abbey, 1999). It is however important to keep in mind the fact that the disorder affects individuals in a different way. Some people may be paralyzed for good while others can recover fully from the disorder (Verrillo, Gellman, 1988). It is also hard to obtain accurate results as it regard the number of individuals who have recovered from CFS. Natural remedies can also be employed to boost an individualà ¢Ã ¢Ã¢â¬Å¡Ã ¬Ã ¢Ã¢â¬Å¾Ã ¢s body energy thereby suppressing chronic fatigue (Leonard, 1997). Variety of products can be used and they include magnesium injection of muscles with low red blood cells magnesium, taking meals rich in fish oil, and melatonin. Other remedies that have show positive response in suppressing the effects of chronic fatigue syndrome include taking of melatonin, ribose, and NADH rich food (Patarca-Montero, 1999). The studies carried on the foods are however, limited and no accurate data can be easily found. Some of the drugs used to counter the effects of chronic fatigue disorder include the use of corticosteroids, and cholinesterase inhibitors like the galantamine (Fisher et al 1997). Methylphenidate like Ritalin, which is a psychostimulant that is used to increase the levels of neurotransmitters thereby helping individuals with attention-deficit disorder, can be used. Some lifestyle techniques can also be employed to counter this disorder and this includes developing a plan that will help is stress reduction, ensuring that the patient gets enough slee p, exercising regularly and maintaining healthy lifestyle. The lifestyle includes eating balanced diets, drinking plenty of fluids, limiting caffeine intake, and participating in aerobics (Meirleir Mcgregor, 2003). Conclusion Chronic fatigue syndrome is more than just being tired because the affected individual is interfered from performing their daily activities in a normal way. Other individuals have been forced to quit high paying jobs, several disabled and others bedridden. The nature of this illness shows that it is even hard to diagnose it (Bell, 1995). Trial and error method of eliminating other possible ailments complicates the diagnostic process. The best remedy therefore is for individuals to live the kind of lifestyles that do not promotes the predisposing factors of the disorder (Voncannon, 2002). This includes living the kind of lifestyle that discourages the development of the disorder. It is also important for physicians to improve their way of diagnosing the disease so that they can be able to come up with comprehensive treatment strategies (Meirleir Patarca-Montero, 2000).
Wednesday, September 4, 2019
Advantages And Disadvantages Of Multimedia Elements Computer Science Essay
Advantages And Disadvantages Of Multimedia Elements Computer Science Essay Text is one of the multimedia elements used in the website. Normally we can found it from Internet. Human are using text to communicate with other people. From Internet we can use E-mail to send text message to other people, we also can use share status or share anything you want to share to give your friend or family know what is on your mind. We also can share or give information in forum. There are some examples of Text elements. Source: http://www.friendster.com (share status) Source: http://www.hotmail.com (E-mail) Source: http://forum.lowyat.net (Forum) Audio Audio is one of the multimedia elements. Audio is sound within the acoustic range available to humans. Commonly we can hear many audio from Internet, Radio, MP3, Computer and so more. Now, we can listen music or download music from website, some people were make song and upload to Internet share to everyone, we also can embed favorite music to blog or website. Some of users use voice call to communicate with friend or family. There are some examples of Audio elements. Source: http://www.deezer.com/en (listen and download music) Source: https://www.blogger.com (embed to blog) Source: http://www.skype.com (voice call website) Video Video is one of the multimedia elements. Video is the technology of electronically capturing, recording, processing, storing and transmitting of images that show scenes in motion. We can find many video from Internet. Some people make a flash video and upload to website to share with others. We also can use video conference to communicate with friend or family. We can watch movie from online or download the movie. There are some examples of Video elements. Source: http://www.youtube.com (watch video) Source: http://www.moviesdatacenter.com (watch movie) Source: Windows Live Messenger (video conference) Graphic Graphic is one of the multimedia elements. Graphic is a visual representation such as a photo, illustration, 3D or diagram. In the computer, a graphic is a file such as JPEG or GIF, there is graphic formats. Graphic is a picture image in the computer. We can use computer graphic to design a picture, flash or game. We can make more effect in the picture, make a flash video or make a game by using graphic software. Inside the Facebook, we also can see the graphic elements when we play the games. There are some examples of Graphic elements. Adobe Photoshop CS5 Extended (make effect in the picture) Macromedia Flash MX (make flash video) Example of game has 3D graphic elements. Animation Animation is one of the multimedia elements. Animation is a visual technique that provides the illusion of motion by displaying a collection of images in rapid sequence. Each image contains a small change. When the images are viewed rapidly, your eye fills in the details and the illusion of movement is complete. We can make images become Animation by using software. The purpose of Animation is make entertainment to everyone. There are some examples of Animation elements. Example of pictures has Animation elements. QUESTION 2 Advantage and Disadvantage of Text Text is silent communications. One of example in our real life is text messaging, it can send message to each other without other people being able to hear what is being said. It is privacy to exchange messages with each other without fear of other people knowing what you are talking about. The advantage of Text is text messaging is the ability to be able to send a message to someone to ask them to call you later regarding something important. At the same time, it doesnt interrupt them with a phone call. It allows them to respond back to you when it is most convenient to them. The disadvantage of Text is sometimes you dont receive all incoming messages from people. Often a personà ¢Ã¢â ¬Ã¢â ¢s text messaging box will get so full with incoming and sent text messages. If the inbox gets too full then the person canà ¢Ã¢â ¬Ã¢â ¢t receive anymore messages unless he or she deletes some of them. Advantage and Disadvantage of Audio Audio is sound within the acoustic range available to human. One of example in our real life is Audio Conference. It can communicate with other people. We can use mobile phone or use Internet to use the audio conference. The advantage of Audio is can combine with other media for example video, computer, MP3. When we are using audio conference, it cans potential for large number of lines on call. The disadvantage is noise can distract participants as well as cut out speaker. Audio is only the sound, it also limited visual stimulation. Advantage and Disadvantage of Video Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion. One of example in our real life is Video Conference. You can see the people face by video conference. The advantage of Video is when using video conference, it can see anyone you want to see, no matter what time of day it may be for anyone involved. Time differences between states and countries can be overlooked without anyone traveling long distances for the conference. The disadvantages are technical difficulties resulting from one or more of the following: software, hardware and network failure. Although advance testing could often identify technical trouble, the unexpected, spontaneous problem sometimes still arose minutes before or even during a videoconference. Advantage and Disadvantage of Graphic Graphic is a visual representation such as a photo, illustration or diagram. A graphic may contain text, but text by itself is not considered a graphic unless it is done in a stylized fashion. One of example in our real life is Advertisement. Because when we want to do advertise, we need do more creative in the poster. It uses a lot of graphic. The advantage of Graphic is quick way for the audience to visualize what you are saying, some of people more interest in the graphic than talk. The disadvantage of Graphic is it takes a lot of time to make. The cost also expensive, depending on the medium used. Advantage and Disadvantage of Animation Animation is a visual technique that provides the illusion of motion by displaying a collection of images in rapid sequence. One of example in our real life is Flash Video. It uses a lot of animation to make a flash video. Mostly animation is use for entertain people. The advantage of Animation is it more creative and mostly used the images like cartoon; it can make people attract it. The disadvantage of Animation is when makes a flash video and upload to Internet or blogger, when other people want to see this flash video, it take a lot of time to load or buffer.
Tuesday, September 3, 2019
Rastafarian Symbolism In The Visual Arts Essay -- VIisual Arts Art
Rastafarian Symbolism In The Visual Arts Works Cited Missing [NOTE: BECAUSE OF CONCERN ABOUT RIGHTS, WE HAVE NOT BEEN ABLE TO POST THE IMAGES THIS ESSAY REFERS TO] "Art has the power of liberating man from certain drudgeries and their way of life. A man who was born in the ghetto can't afford to be a Sunday painter, his whole life is involved in getting across his ideas; Rastafarianism, politics, Black culture and all that. Even our meeting here now is an artistic involvement. Some people do art with love here, politics there and so forth; now, to me art is one cosmic consciousness. The way you love, live, and even the way you hate: even your negative expressions connote a certain art-form. So I really do not separate my art from my other sphere of life."-Ras"T"(Barrett,187) The words of Ras"T", captured by Leonard E. Barrett, Sr. in his book The Rastafarians, are an excellent representation of the Rastaman's struggle to survive as an artist in Jamaica. They also reveal the core concept of Rastafarianism itself; the idea that one is born with Rasta inside them, and a true Rasta lives every second of every day in spiritual contact with Jah, Rastafari. One cannot be a Sunday worshiper of Rastafarianism. For the Rastafarian artist, every stroke of every painting or each chip of wood from the sculpture is inspired by Jah. Despite the problems such as lack of materials, and difficulties in getting exposure for their work, many members of the Rastafarian movement have turned to artistic expression in order to convey the Rastaman's message, and also as a means of out-letting their spirituality. These expressions include visual art, music, and poetry. In some cases, the Rastas use their artistic ability to create crafts an... ...t understand the symbolism and the thoughts that are put into such incredible displays of talent. The Rastafarians have contributed so much to their country's culture that goes by unnoticed. In the words of Barrett:"Great social developments are not always made in the halls of parliament or in the citadels of learning. These institutions merely react to the dreams of the creative mass. Some of the most creative trends in nations' development are born in the dreams of the visionaries, the radicals, the seers, and the charismatic prophets."(Barrett, 266). Many of these prophets are artists, and their beliefs are so strong that they are able to rise out of the poverty they live in and project their messages anywhere they will go. The Rastaman will be heard, and through the symbolism discussed in the previous pages, he can be heard. If only people will listen, and look.
Against an Alcohol Age Limit Essay -- Argumentative Persuasive Drinkin
Drinking Age: Lowered or Not à à à à à The drinking age in the United States is 21. How ridiculous is that? You are able to do so many things at the age of 18. When a person reaches the age of 18, he or she can leave their homes or be kicked out, and become their own legal guardian. They no longer are required to have their parents sign their name to any documents pertaining to them, and are now considered an adult except when it comes to alcohol. When a person 18 or older commits a crime, they will be tried as an adult. Now the 18 year old no longer goes to Juvenile Hall when convicted of a crime, but instead they go to jail, state prison, federal prison, or even death row. At 18, they are held fully responsible for their own actions, and must accept the consequences. Donââ¬â¢t you think we s...
Monday, September 2, 2019
Analysis of Pinkââ¬â¢s Stupid Girls Essay
1. Pinkââ¬â¢s Stupid Girls created 2006 2. Narrative or storyline; Young girl is sitting on couch, watching TV which shows a range of depictions of women. The ââ¬Ëgoodââ¬â¢ and ââ¬Ëbadââ¬â¢ angels hover over her shoulders. The images include women as ditzy, carrying little dogs, car-washing in minimal clothing, as the president, playing football. 3. The central discourses are stereotypes regarding women and the choices that women make. The entire video clip presents the range of ways women can be in our society. For example, they can be insecure about their appearance, with scenes showing them getting spray-tans, having cosmetic surgery and the bulimic girl in the toilets. Almost in contrast, the women are shown as being defined by their sexuality and using their appearance to gain approval, such as in the dancing, bedroom and the car-washing scenes. This idea is also evident in the gym and bowling alley skits. There are also images of women being strong and independent, especially in the president scenario and the final scene. The central discourse challenges many of the existing stereotypes which define women by their appearance, rather than by the quality of their contributions to society. For example, in the opening scene, a young girl is depicted sitting on a couch watching television. As she changes channels, different representations of women are shown. The girl is holding a Barbie doll and handbag, representing the discourse of women as judged by their appearance and fashion-conscious. However, she is wearing a football jersey which represents a different discourse of women as sportswomen and perhaps being able to match the boys. In another example, in the car-washing scene, the girl is wearing very minimal clothing, sliding all over the car in the suds, projecting her breasts in a bikini top, and appearing to be particularly clumsy. Her movements are quite suggestively sexual, and in fact many of her ââ¬Ëposesââ¬â¢ replicate those in the bedroom scene, so the message is about a woman being an object of sexual gratification. This depiction of women is quite downgrading. Overall the representation of young women is negative, with the positive versions presented as the preferred, but not common, discourse. A positive representation of women is in the president scene. The lyrics ask ââ¬Ëwhat happened to the dream of a girl presidentââ¬â¢, and the images suggest a woman who is intelligent, strong and powerful. This is achieved through a range of visual techniques: the use of costume ââ¬â a jacket and glasses, camera angle ââ¬â from below to emphasise status, props ââ¬â the USA flag, portrait in background, and the lectern. The action of striking a fist on the lectern also emphasises the confidence of the character, in direct contrast to other scenes which show the woman as insecure, comparing herself to other girls and trying to attract the attention of men. . The video clip uses a range of technical aspects to help convey the overall message. For example, very conventional codes are used in the opening scene, where the angel is depicted in white and the devil in black and red. The connotation of white is of purity and innocence, whereas the connotations often associated with black and red are negative. Fire is suggestive of hell and the smoke or cloud around the white angel suggests heaven. The message is thus a very heavy laden one, making one view of women good and the other bad.
Sunday, September 1, 2019
Continental Drift and Plate Tectonics Essay
Introduction: The Beginning of the ââ¬Å"Continental Drift Theoryâ⬠In the middle of the eighteenth century, James Hutton proposed a theory, uniformitarianism; ââ¬Å"the present is the key to the pastâ⬠. It held that processes such as geologic forces- gradual and catastrophic-occurring in the present were the same that operated in the past. (Matt Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered that the coasts of the eastern part of South America and the western coasts of Africa fit together like a jigsaw puzzle and this fit becomes especially prominent as the edges of the continental shelves have similar shapes and thus, appear to be once fitted together. (Figure 1.1 and Figure 1.2) The similarity of southern continentsââ¬â¢ geological formations had led Roberto Mantovani to speculate that all continents had once been a supercontinent and was smaller in its volume than it is now. Through volcanic activity, fissures are created in the crust causing this continent to break apart. However, this theory, known as the Expanding Earth Theory has since been proven incorrect. The Theory of Continental Drift In 1912, The Theory of Continental Drift was intensively developed by Alfred Wegener, who claimed that the world was made up of a single gigantic supercontinent named Pangea since the Permian period, 250 million years ago. It began forming at the beginning of the Carboniferous period, 365 million years ago, when Gondwana collided into Laurussia producing the Appalachian mountain belt in eastern North America and closing in Paleo-Tethys Ocean and modern landmass became exposed to air. Alexander Du Toit then suggested that 145-200 million years ago, in the middle Jurassic Period, Pangea started breaking up into two smaller supercontinents, Laurasia in the northern hemisphere and Gondwana in the southern hemisphere, with Tethys Sea and North Atlantic Ocean separating the two supercontinents. The late Jurassic era began the formation of the Rocky Mountains and Sierra Nevada mountains. In the Cretaceous Period, 65 million years ago, the two supercontinents then began fragmenting into the present seven continents. (USGS, 2012) The Tethys Sea that lay between the two landmasses was subducted beneath Eurasia, forming the lower Atlantic Ocean. Eventually, it disappeared. (Nelson Thomas, 2007) (Figure 2) Wegener proposed that continents were moving at about one yard per century and supported this theory with several points of evidence. Evidence supporting the Theory of Continental Drift (Alfred Wegener and Du Toit) Alfred Wegener matched up coastlines, and he realized that by fitting the continental shelves together, cratons formed a contiguous pattern across the boundary of South America and Africa. (Lois Van Wagner, 2013) He realized that mountain ranges that ended at one coastline seemed to begin again on another such as ancient mountains in South Africa that align with the mountains in near Buenos Aires in Argentina. (Sant, Joseph, 2012) He discovered earthworms of the family Megascolecina, who are unlikely to be long-distance migrators, were found in soils of all the Gondwanaland continents. (kangarooistan, 2009) This identical species could not have arisen on different continents without some variations. (WiseGeek, 2010) Fossil remains of a prehistoric reptile known as the Mesosaurus had been uncovered on both sides of the South Atlantic coasts, yet the creature was unable to swim across the Atlantic Ocean. ( Lois Van Wagner, 2013) Fossils of the land reptile, Lystrosaurus were discovered in South America, Africa and Antarctica. (Sant, Joseph, 2012). He also discovered the fossil plant Glossopteris was distributed throughout India, South America, Southern Africa, Australia and Antarctica. (USGS, 2012)(Figure 3) Alexander Du Toit traveled to Brazil and Argentina where he found similarities in the fossils and rock strata to those found in South Africa such as the fossilized remains of Mesosaurus in fresh water deposits, dune deposits capped by basalt flows, tillite and coal beds. Similar layers of rock were formed in Antarctica, Australia, South America, Africa and India. (Figure 4) Widespread distribution of Permo-Carboniferous glacial sediments in South America, Africa, Madagascar, Arabia, India, Antarctica and Australia and striations that indicated glacial flow away from the equator and towards the poles were discovered and supported the theory of Continental Drift which proposed that southern continents were once located over the South Pole region and covered by ice sheets. (Lois Van Wagner, 2013) (Figure 4) He also discovered a base layer of shale scratched by glaciers and covered by layers of tillite in South Africa, a continent of a tropical equatorial climate. Tillites and varves dating back to 2 billion years ago, were found in Canada and India, indicating glaciation on a worldwide scale. Such tillites were found on all major continents except Antarctica, which has been the most extensive glacial continent in earthââ¬â¢s history. (kangarooistan, 2009) Additionally, fossils of tropical plants in the form of coal deposits were found in Antarctica which implies that Antarctica had to be closer to the Equator. (USGS, 2012) This study of changes in climate taken on the scale of the entire history of Earth is known as paleoclimatology. Sediments of rifting have proved the drifting apart of Pangea. The rifting that formed the South Atlantic Ocean began late in the Mesozoic Period when Africa and South America began to pull apart. Water from the south then flowed in over time, thus forming the evaporites now found along the coastlines there. (Lois Van Wagner, 2013)(Figure 5) However, Wegener believed that only the continents were moving and they plowed through the rocks of the ocean basins. (Colliers Encyclopedia, 1996) Harold Jeffreys then argued that it is impossible for continents to break through solid rock without breaking apart. (USGS, 2012) Wegener also claimed that the centrifugal force of the spinning planet had forced the continents sideways, parallel to the equator; tidal pull from the sun and moon had caused lateral movement. (Sant, Joseph, 2012) His orders of magnitude were too weak. Thus, his theory was dismissed. (Lois Van Wagner, 2013) Further development and support of the ââ¬Å"Continental Drift Theoryâ⬠in the 1960s After World War 2, the U.S. Office of Naval Research intensified efforts in ocean-floor mapping, leading to the discovery of the Mid-Atlantic Ridge to be part of a continous system of mid-oceanic ridges on all ocean floors, prompting Harry H. Hess to suggest the theory of sea-floor spreading. The oldest fossils found in ocean sediments were only 180 million years old and little sediment were accumulated on the ocean floor. Thus, he suggested that seafloors were no more than a few hundred million years old, significantly younger than continental land due to hot magma rising from volcanically active mid-oceanic ridges, spreading sideways, cooling on the seafloorââ¬â¢s surface due to cooler temperatures of the sea, solidifying to create new seafloor, thereby pushing the tectonic plates apart. (Edmond A. Mathez, 2000) The realization that the shape of the Mid-Atlantic Ridge and the Atlantic Coast are strikingly similar substantiated the claim that the continents had been joined together at the Mid-Atlantic Ridge. (J. Tuzo Wilson, 1996) (Figure 6) The cause of the continental drift that Wegener was unable to explain had been further researched on by Arthur Holmes who claimed that the movement of continents was the result of convection currents driven by the thermal convection in the heat of the interior of the Earth, namely the mantle. The heat source of the mantle comes from radioactivity decay in the core. (Figure 7) At constructive plate boundaries, molten basalt flows out on either side of the ridge and cools with the iron particles in the basalt aligning with the earthââ¬â¢s magnetic field which reverses direction every few hundred thousand years. (Lois Van Wagner, 2013) Due to magma cooling, the polarity of rocks will be recorded at the time it was formed. (Figure 8.1) In 1950, researchers of paleomagnetism discovered that there were alternating regions of normal and reversed magnetic directions symmetrically disposed on both sides of the Mid-Atlantic Ridge ââ¬âmagnetic stripping. (J. Tuzo Wilson, 1996) Harry H. Hessââ¬â¢ theory was thus proven by the magnetic anomalies in the oceanic crust. (Nelson Thomas, 2007) (Figure 8.2) It was also discovered that the youngest rocks were closest to the mid-oceanic Ridge and the oldest rocks were near the coasts of the continents. When scientists began collecting magnetic data for North America and Europe, they discovered the north pole seemed to be moving about over time. (ALLA, 2009) However, when data from other continents was collected for the same time frames, it showed different polar locations, thus supporting that continents were moving about. The Theory of Plate Tectonics The theory of plate tectonics held that the Earthââ¬â¢s lithosphere, the Earthââ¬â¢s crust and the uppermost mantle, is broken into seven macro-plates and about twelve smaller ones, averaging 50 miles in width. (U.S. Dept. of the Interior, Geological Survey, 2007) Any plate may consist of both oceanic crust and continental crust. (Colliers Encyclopedia, 1996) (Figure 9) It suggests that the ocean floor began to spread at constructive plate boundaries, and continents, existing on ââ¬Å"platesâ⬠, moved due to convection currents in the mantle and constant sea-floor spreading. (The Columbia Electronic Encyclopedia, 2011). They drag and move plates above them due to rising magma spreading out beneath the earthââ¬â¢s crust. As two oceanic plates move apart, magma from the underlying asthenosphere mantle wells up from oceanic ridges and becomes rigid enough to join the lithosphere of the plates on either side of the plate boundary, creating new seafloor and eventually, an oc ean is opened up. (J. Tuzo Wilson, 1996) (Figure 10) Examples are the Atlantic Ocean formed between South America and Africa. New rock is created by volcanism at mid-oceanic ridges and returned to the Earthââ¬â¢s mantle at oceanic trenches where the denser plate is subducted under the other, forcing the earthââ¬â¢s crust back into the mantle. (J. Tuzo Wilson, 1996) This process is known as the ridge push and slab-pull. (Figure 11) Different plate tectonics movement and subsequent tectonic activities Transform plate movement causing earthquakes: Seismic waves disrupting the continents in the form of earthquakes are due to the great amount of stress and energy built up by the friction of the moving plates, especially during transform plate movement, where plates slide past each other in a grinding, shearing manner and form tear faults (Columbia Electronic Encyclopedia, 2011). (Figure 12.1) There is gradual bending of rocks before the ductile limit of rocks is exceeded, causing the plates to lock and the fault to break, leading to sudden release of stored energy, causing earthquakes. (Nelson Thomas, 2007 ) An example is the strike-slip fault, San Andreas Fault in California. (Figure 12.2) (WiseGeek, 2010) Oceanic and Oceanic convergent plate movement: Other evidence of plate tectonics movement are most of the worldââ¬â¢s active volcanoes located along or near the boundaries between shifting plates known as plate-boundary volcanoes. (J. Tuzo Wilson, 1996) When two oceanic plates collided, the denser plate will subduct under the other, forming a deep oceanic trench and form magma through hydration or decompression melting. The magma being less dense than the surrounding mantle, rises and escapes to the sea-floor through cracks in the earthââ¬â¢s crust, forming submarine volcanoes that rise above water to form a chain of volcanic islands known as island arcs, such as the Japan Islands. (Figure 13) Examples would be the Pacific Plate subducting underneath the North American Plate creating the Kuril Trench and the Japan Trench that can be found along the Pacific Ring of Fire. Many volcanoes such as Mount St. Helens, Mount Fuji in Japan and Mount Pinatubo in the Phillipines are located along the perimeter of the Pacific Ocean Basin where boundaries of several plates such as the Nazca and the Cocos Plate are found, forming the Ring of Fire. (Fraser Cain, 2009) (Figure 14) Volcanoes formed not due to tectonic activities: 5 per cent of the worldââ¬â¢s volcanoes are formed at isolated ââ¬Å"hot spotsâ⬠and many intra-plate volcanoes form roughly linear chains along the middle of oceanic plates. (The Columbia Electronic Encyclopedia, 2011)Examples are the Yellowstone National park and Hawaiian Islands, an intra-plate volcanic chain developed by the Pacific plate passing over a deep, stationary ââ¬Å"hot spotâ⬠, located 60 km beneath the present-day position of the Island of Hawaii. Heat from this hotspot produced a constant source of basaltic magma by partly melting the overriding Pacific Plate. This magma rises through the mantle to erupt onto the seafloor, forming an active seamount. Over time, countless eruptions caused the seamount to grow until it finally emerges above sea level to form island volcanoes. The continuing plate movement eventually carries the island volcano away from the hotspot, cutting it off from the ââ¬Å"hot spotâ⬠and creating another island volcano. This cycle is repeated, forming the Hawaiian Islands. (U.S. Dept. of the Interior, Geological Survey, 2007) (Figure 15) Continental and Continental convergent plate movement: Continental fold mountain ranges are evidence of two continental plates that are thick and buoyant thus, preventing both plates from subducting. Instead, the two plates collide into each other forming fold mountain ranges in a process known as orogenesis. An example is the high elevation of the Tibetan plateau, fringed to the south by the Himalayas as the edges of the Indian and Eurasia plate buckle, uplift, fold and deform. Mt. Everest is the highest summit on Earth, yet Yellowband limestone that was originally part of the shallow seals of the Tethys Ocean was found on Mount Everest at a height of 8462m. (Figure 16) Oceanic and Continental convergent plate movement: Mountains are formed when oceanic crust is subducted under a continental crust, resulting in melting of rock, thus volcanic activity and causing the continental crust to deform, rise and buckle upwards under compressional forces. Examples are the Andes Mountain, the Chile-Peru Trench and the uplift of the Rockies and Appalachians in the past. (The Columbia Electronic Encyclopedia, 2007) The Table Mountains was formed approximately 250 million years ago, due to the Pacific plate subducting under the North American plate, (Mary Ann Resendes, 2012) thus creating the Sierra Nevada foothills, subsequently creating the Cape of Good Hope as the ocean erodes the soft sandstone of Table Mountains on the coast. (National Geographic, 1996) Other tectonic activities such as the Wadati-Benioff zones, that are earthquake zones parallel to oceanic trenches are also formed at such subduction zones and inclined from 40 to 60 degrees from the horizontal, extending several hundred kilometres into the mantle. (Figure 17) Continental and Continental divergent plate movement: When two continental crusts are pulled apart due to tensional forces, the area sinks and forms a rift valley and sea such as the East African Rift Valley and the Red Sea that runs from the Jordan Valley and into East Africa, already dotted with volcanoes such as Hermon. This is due to the area being stretched, causing the crustal material to thin, weaken and sink due to lowered density. (Figure 18) Isostasy Also, isostasy takes place wherever a large amount of weight such as the fold mountain ranges created from plate tectonics movements is formed or glaciers, pushes down the Earthââ¬â¢s crust and creates a small dent. Isostasy also takes place at divergent plate boundaries when a large amount of weight is removed from an area, causing that portion of the Earthââ¬â¢s crust to rise. Therefore, equilibrium in the earthââ¬â¢s crust is achieved such that forces elevating landmasses balances those tending to depress landmasses. (Learning Network, 1998) (Figure 19)
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