The Pros And Cons Of Shale Gas Environmental Sciences Essay

The Pros And Cons Of Shale Gas Environmental Sciences Essay Shale gas development has significant negative and positive environmental impact. Negative environmental impact is due to the process of shale gas development and positive impact is through a substitution of clean natural gas to other energy sources. This paper is organised in three parts. In the first part, shale gas development and potential of shale gas is described. In the second part, environmental challenges in the development of shale gas are described. In the third part, environmental benefits as a result of shale gas are discussed. Shale Gas and its potential: Shale gas is natural gas. It is stored in organic rich rocks such as dark-coloured shale, inter bedded with layers of shaley siltstone and sandstone [1]. Shale is a fine-grained rock made up of ancient compacted clays or mud and can be the source, reservoir and the seal for the gas. Shale gas plays are classified as a continuous type gas accumulations extending throughout large areas, typically with low permeability [1]. Shale gas is considered as unconventional gas source and same techniques used for conventional shallow gas development may also be used with shale gas drilling [1]. Shale gas is extracted through a process known as hydraulic fracturing which was developed in the United States in 1948 [3]. Hydraulic fracturing involves injecting a mixture of water, sand and chemicals into rock formations to stimulate oil and natural gas production shown in the figure 1. Figure1: Shale gas extraction process [2] Hydraulic Fracturing creates fractures that extend from a borehole into shale formations. Hydraulic fracture is formed by pumping a fracturing fluid into the well bore at a rate sufficient to increase the pressure down the bore hole fracturing the surrounding shale rock formation [3]. Solid proppant (like sieved round sand) is added to the fracture fluid to keep the fracture open after the injection stops. Shale gas potential: Shale gas fields were largely untapped until recently due to the difficulty and cost to extract the gas. As conventional natural gas production has been decreasing, demand for the unconventional natural gas is more than ever now. This fact coupled with improvements in extraction methods has made it possible to explore the shale gas reserves. Recoverable shale gas reserves increases total gas availability of the world by 40 percent per the report by Energy Information Administration (EIA) of USA. A new EIA-sponsored study reported initial assessments of 5,760 trillion cubic feet of technically recoverable shale gas resources in 32 foreign countries [6], with China topping the list with 1275 trillion cubic feet of shale gas reserves followed by USA with 862 trillion cubic feet [Appendix 1]. In 2010, U.S. shale gas production was 4.87 trillion cubic feet (23 percent of total U.S. natural gas production), compared with 0.39 trillion cubic feet in 2000. IEA predicts that shale gas will account for about 46 percent of U.S. natural gas production by 2035[6]. Rising production from shale gas resources in the U.S. has been credited with both lower natural gas prices and declining dependence on imported natural gas [6]. In most of the developing countries, shale gas development has not started yet. Energy hungry countries like India and China can greatly benefit from their recoverable shale gas resource as recent oil prices trend shows that oil is no longer a cheap commodity. At the current level of consumption, world may have 250 years supply of natural gas as result of new shale gas reserves around the world as per International Energy Agency (IEA) [7]. Shale gas is a huge deal per Shells CEO Peter Voser. BPs ex CEO Tony Hayward hailed shale gas as complete game changer [8]. These comments from the prominent energy experts show the importance of shale gas as future potential energy source. Figure 3: Estimated global shale gas recoverable resources As is often the case with any resource development, shale gas production also has raised local environmental concerns, largely centering on the amount of water used in the fracturing process and the need to handle, recycle, and treat fracturing fluids in a manner that addresses the risk of spills that can potentially affect water quality. Do other countries have similar opportunities to develop shale gas? To begin to address that question, EIA sponsored Advanced Resources International, Inc., to assess 48 gas shale basins in 32 countries, containing almost 70 shale gas formations. This effort has culminated in the report: World Shale Gas Resources: An Initial Assessment of 14 Regions Outside the United States. Technically recoverable natural gas resources in the assessed basins totaled 5,760 Tcf. Adding the estimated U.S. shale gas technically recoverable resources (862 Tcf) to the assessments in the study gives a total of 6,622 Tcf. For comparison, most current estimates of world technically recoverable natural gas resources include few if any of the resources assessed in this study and total about 16,000 Tcf. Adding identified shale gas resources to current estimates of other gas resources increases total world technically recoverable resources by over 40 percent, to more than 22,000 trillion cubic feet, said EIA Administrator Richard Newell. Estimates of shale gas resources in other parts of the world are highly uncertain. The practicality of using such resources has only recently become apparent, and many countries are just now beginning to understand how to conduct assessments of how much shale gas they may have. Nonetheless, the aggregate estimate is probably quite conservative, since the study excluded several major types of potential shale gas resources: Nations outside the 32 countries studied. These include Russia and the Middle East, which have very large resources of conventional gas. Some shale basins in the countries studied. In many cases, no estimates are possible yet for these basins. Offshore resources. Of the countries covered in the EIA-sponsored study, two groups may find shale gas development most attractive. The first is those countries that currently depend heavily on natural gas imports but that also have significant shale gas resources. These include France, Poland, Turkey, Ukraine, South Africa, Morocco, and Chile. The second group is those countries that already produce substantial amounts of natural gas and also have large shale resources. In addition to the United States, this group includes Canada, Mexico, China, Australia, Libya, Algeria, Argentina, and Brazil. A new EIA-sponsored study reported initial assessments of 5,760 trillion cubic feet (Tcf) of technically recoverable shale gas resources in 32 foreign countries, compared with 862 Tcf in the United States. Technically recoverable natural gas resources in the assessed basins totaled 5,760 Tcf. Adding the estimated U.S. shale gas technically recoverable resources (862 Tcf) to the assessments in the study gives a total of 6,622 Tcf. For comparison, most current estimates of world technically recoverable natural gas resources include few if any of the resources assessed in this study and total about 16,000 Tcf. Adding identified shale gas resources to current estimates of other gas resources increases total world technically recoverable resources by over 40 percent, to more than 22,000 trillion cubic feet. In terms of recoverable shale gas resources, China takes the top spot, with an estimated 1,275 Tcf. The US is second, with 862 Tcf, followed by Argentina with 774 Tcf and Mexico with 681 Tcf. The growing importance of US shale gas resources is also reflected in EIAs Annual Energy Outlook 2011 (AEO2011) energy projections, with technically recoverable US shale gas resources now estimated at 862 trillion cubic feet. Given a total natural gas resource base of 2,543 trillion cubic feet in the AEO2011 Reference case, shale gas resources constitute 34% of the domestic natural gas resource base represented in the AEO2011 projections and 50% of lower 48 onshore resources. As a result, shale gas is the largest contributor to the projected growth in production, and by 2035 shale gas production accounts for 46% of US natural gas production.

Causes And Effects Of Deforestation In Myanmar Environmental Sciences Essay

Causes And Effects Of Deforestation In Myanmar Environmental Sciences Essay According to the Food and Agriculture Organization of the United Nations U.N.FAO, there are about 31,773,000 ha hectares or 48.3 of forests in Myanmar. An average of 372,250 ha or 0.95% of forest have been lost annually between 1990 and 2010. The organization states that within the period of 20 years (1990-2010), around 7,445,000 ha or 19.0% of the total forest has been cleared in Myanmar. Myanmar is one of the top ten countries that are happening highest deforestation rate in the world, and its rank is seven. The Rangoon-based Biodiversity and Nature Conservation Association (BANCA) alerts that Myanmar is meeting a deforestation crisis because of natural disasters (hurricanes, floods, drought and fires), human activities (logging, slash-and-burn agriculture, cutting trees for fuel, mining operations, dam building, clearing land for livestock grazing and oil extraction) and overpopulation. If deforestation cannot be controlled by government, the result could be very disastrous. It has negative impacts on environmental degradation and direct biodiversity loss. Exporting timber and human population are the main causes of deforestation in Myanmar. The Global Witness Non-Governmental Organization (NGO) manipulated that Myanmar shipped at least one million cubic meters of timber into China in 2002. Between 2010 and 2011, government exported 864,000 metric tons of timber and got US$600 million from it. Moreover, according to the UN FAO report that Burmas rural populations of around 70% or at least 30 million rely on forests for their basic needs in 2009. Government and people do not aware if they cut a lot of trees for their profits; it will affect on ecosystem and happen a lot of natural disaster in Myanmar. The purpose of this paper is to show causes and effects of deforestation in Myanmar. In particular, the impact of climate changes is very serious problem in Myanmar due to deforestation. This paper will discuss the plans of government to solve these problems ,and it will also provide some possible suggestions to protect the forests. 1.0 Causes The meaning of deforestation is cutting, clearing and removing of trees for various reasons such as logging, slashing-and-burning agriculture, clearing land for livestock, building dam. Sometimes, natural disasters can extremely destruct forests. For instance, Cyclone Nargis destroyed a lot of trees in Myanmar on 2 and 3 May 2008. Myanmar is developing country, so the government and people are extremely depend on forests. They cut down a lot of trees for various reasons, but the main point is for short-term economic benefits (Putatunda, 2011). Deforestation can be caused not only human activities, but also natural disasters. In Myanmar, government exports a lot of natural resources to other countries, but they got more money by exporting timber. According to the parliamentary Natural Resources and Environment Conservation Committee, Myanmar exports a lot of teaks by legal or illegal. The London-based Environment Investigation Agency claims that Myanmar exported 1.6 million tones of teak per annually to neighboring countries such as India, China, Bangladesh, Thailand and Malaysia. http://www.itto.int/files/user/mis/mis%20charts%20homepage/snap20111201.gif The agency states Myanmar got $5.7 billion by exporting 18 million cubic meters of wood log between 2000 and 2010. According to statistics, Myanmar has more than 16.32 million hectares of forest, and the area of teak is 24,300 hectares while the area of hardwood is 324,000 hectares. In Myanmar almost 1.98 million cubic meters of hardwood and 283,000 cubic meters of teak are used in Myanmar per annual. As a result, cutting a lot of trees for exporting is threatening Myanmar forests. Overpopulation affect on forests because they destroy a lot of trees for their profit. In Myanmar, the population is increased approximately one million annually. The population Myanmar is 54,584,650 in 2012 .According to UNFAO, 70 percent of the Myanmar people live in rural area, and they rely on forests for their basic needs and sustenance and income. Similar to Indonesia, people who get less than US$ 1 cut trees to get a few income for short-term (Stolle, 2008). Deforestation can be caused by not only man-made, but also natural disasters. In Myanmar, forest fire is one of the main problems to destroy forests. Myanmar lost up to 10 tons of forest fuel because of forest fire. As a result, every 30 to 70 tons of top forest soil are destroyed in Myanmar. Myanmar is facing natural disasters such as cyclones, landslides, earthquakes, tsunami, fire and drought. They are also real threats to Myanmars environment. Effects Burning trees and clearing forest extremely affect on environment. A lot of greenhouse gases including carbon dioxide are emitted from deforestation. Hence, the temperature of global is rising, so climate changes and soil erosion happen in Myanmar. 2.1 Climate Changes A lot of natural disasters are threatening Myanmars forest such as cyclones, earthquakes and floods (Moe, 2009). Cyclone Nargis destroyed trees and livelihood of people more than earthquake and floods. Cyclone Nargis was the top deadliest and most caustic tropical cyclones to ever strike Myanmar (The New York Time, 2012). The cyclone notably affected a total of 37 townships. The UN predicts more than 2.4 million people were affected by Cyclone. According to official figures, 53,800 were missing, and 84,500 people were killed. It also destroyed a million acres of rice paddies, trees and killed three-fourths of the livestock with its seawater surges. 2.2 Soil erosion and soil fertility loss In Myanmar, soil erosion is one of the most serious problems, and government cannot be controlled until now, so the agricultural products of Myanmar are falling. The fertility of the soil will reduce if the surface soil is eroded, and it can turn agricultural land into desert land. To prevent soil erosion, Myanmar should preserve forests and grasslands. If soil erosion cannot be preserved, it will lead to flooding. Weather and agricultural experts argue that they get 4 inches of rain from the flood areas, but flooding problems never happen with this amount of rainfall in the past. Not only nutrient depletion but also ecological, social and economic problem can be happened because of soil erosion. Solutions A lot of natural disasters are threatening people in Myanmar. Most disasters are caused by deforestation. So, the government are trying to reduce deforestation. They have three plans for that. First of all, they will completely ban exporting timber to other countries in 2014 (William Boot, 2012). However, it is difficult to stop illegal logging and exporting to China. The reason is Chinas border is very close with northern part of Myanmar. Most poor indigenous people are relying on forest for their basic need. Although the government does not allow to cut trees, they may do continue, but their strategic is a few positive effects on stopping illegal logging and exporting to not only China but also other countries. The second is reforestation. Every June or July, the government order to plant trees in the whole country. Moreover, the government has dictated its citizen between the ages of 11 and 60 must plant five trees per annually in China. The government mentions that the result of their program is they have been planted at least one billion trees since 1982. Although the government of Chinas plan succeed, in Myanmar, their programme failed since after planting trees, nobody care about them. In the peoples mind, their responsibility is just planting trees. The last strategy is collaboration with UN organization . It established The National Commission for Environment Affairs(NCEA) which purpose is to support the environmental protection and reduce the environmental degradation. The government expects this collaboration can prevent deforestation in Myanmar. The best solution is giving job to poor people. If they have enough money for their basic need, they will not destroy the forests. They will not care how many disasters happen and the government announces the rules because money is more important than retaining the environment for them. Furthermore, recycling and reusing items are also the best solution. For example, industries are using a lot of bamboo to produce paper. If people and students reuse the recycling paper, they may reduce using bamboo. These solutions may decline deforestation in Myanmar. Conclusion In conclusion, Myanmar was covered a lot of forests in the past, but nowadays, the coverage of forests decreased significanly in Myanmar. Exporting teaks and overpopulation are the main causes to be facing deforestation in Myanmar. Myanmar is poor country, so government budget depend on exporting teaks to other countries. Nearly 283,000 cubic meters of teak and 1,98 0,000 cubic meters of hardwood are used for exporting in Myanmar per year. Increasing population is also the main problem. Approximately one million people are incresing per annually. Most of them are poor, so they rely on forests for their basic needs. The result of destroying forests is emitting a lot of greenhouse gases. As a result the temperature is rising, and it affects on climate and soil of Myanmar. By changing climate, a lot of natural disasters are happening in Myanmar such as Cyclone Nargis, earthquakes, floods and drought. Cyclone Nargis destroyed a lot of trees and affected more than 2.4 million people, and it was nightmare for people. Myanmar has no many good place for agriculture due to deforestation. Government tried to solve deforestation , but it did not affect on the problem. Reducing unemployments and recycling items may prevent destroying the forests. If the government cannot control deforestaionthe, a lot of extreme natural disasters will occur in Myanmar. If there is no enough trees, the temperature will be higher and higher, and the death rate of people will sharply increase in hot season. Health problems and economy problems will also happen. It is believe that if there is no trees, animals can not survive. If there is no animals, all people cannot also survive. By maintaining the environment, the world will be beautiful.

Double Standard for Women of Homers Odyssey Essay -- Homer Odyssey wo

Double Standard for Women of the Odyssey      Ã‚   Odysseus plans to tiptoe back into his hall through various schemes, one of which is to become beneficial and amiable to the maidservants. With this motivation, he offers to guard the hearth so that the fire won’t dwindle, but the response he receives is more than unwelcoming. Melantho, a beneficiary of Penelope, spurns him saying:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   You must be crazy, punch drunk, you old goat.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Instead of going out to find a smithy—or a tavern bench—you stay   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   putting your oar in, amid all our men.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Numbskull not to be scared! The wine you drank   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   has clogged your brain, or are you always this way,   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   boasting like a fool? Or have you lost   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   your mind because you beat that tramp, that Iros?   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Look out, or someone better may get up   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   and give you a good knocking about the ears   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   to send you out all bloody. (18.405-15).   Ã‚  Ã‚  Ã‚   Unexpectedly and unconventional for his character, Odysseus says: â€Å"One minute: let me tell Telemakhos how you talk in hall, you slut; he’ll cut your arms and legs off† (18.416-20). â€Å"This hard shot took the women’s breath away and drove them quaking to their rooms, as though knives were behind: they felt he spoke the truth† (18.421-23).   Ã‚  Ã‚  Ã‚   From the perspective of Melantho, her reason to believe the hungry bellied pariah, Odysseus, seems unclear. There seems to be a lapse in her reasoning. Since the old beggar’s arrival at Odysseus’ estate, Telemakhos—not ever publicly acknowledging the hunched-over man's entry—appears to wholly neglect him. Intimidated by the suitors’ death threats and revealing Odysseus’ identity, the only way out for Telemakhos, ... ... Athens," 5-16. Diana Buitron-Oliver and Beth Cohen,   "Between Skylla and Penelope: Female Characters of the Odyssey in Archaic and Classical Greek Art," pp. 29-58. "Female Representations and Interpreting the Odyssey," by Seth Schein, pp. 17-27. Griffin, Jasper. Homer on Life and Death, 1980, Clarendon Press. Richard Brilliant, "Kirke's Men: Swine and Sweethearts," pp. 165-73. Helene Foley, "Penelope as Moral Agent," in Beth Cohen, ed., The Distaff Side (Oxford 1995), pp. 93-115. "The Odyssey, History, and Women," by A. J. Graham, pp. 3-16 Lillian Doherty, Siren Songs: Gender, Audiences, and Narrators in the Odyssey (Ann Arbor 1995), esp. chapter 1. Marilyn Arthur Katz, Penelope's Renown: Meaning and Indeterminacy in the Odyssey (Princeton 1991). Nancy Felson-Rubin, Regarding Penelope: From Courtship to Poetics (Princeton 1994).

Teen Depression and Suicide :: Teenage Depression

Depression has become a big issue among the adolescent world these days. It is something that is overlooked much of the time, and is often even hidden by other things. The suicide rate for teenagers has increased more than 200% over the last decade. Recent studies have shown that more than 20% of adolescents in the general population have emotional problems and 30% of adolescents attending psychiatric sessions suffer from depression. Maurice Blackman MB, FRCPC says that, â€Å"The majority of teenage depressions can be managed successfully by the primary care physician with support from the family.† Teens with psychiatric illness are 20 times more likely to die from accidents or suicide than adults Is depression in adolescents a significant problem? As in the afore stated paragraph a baffling 20% of adolescents in the general population have emotional problems! Despite this, depression in this age group is greatly under diagnosed, leading to serious difficulties in treatment of this issue. Adolescence is a time of emotional turmoil, mood instability, gloominess, great drama and heightened sensitivity. Possible suicidal thoughts can emerge from this troubled mind. Adolescent depression may present itself primarily as a behavior or conduct disorder, substance or alcohol abuse or as family turmoil and rebellion with no obvious symptoms normally associated with depression. Significant acute crisis in the teenager's life may also involve depression. Significant stresses include divorce, parent or family quarreling, physical or sexual abuse and alcohol or substance abuse. The teenager who exhibits signs of depression may be going through these tough situations. Teenagers can be oppositional and negative when depressed. If the teenager is an active participant in the treatment process than the physician will be able to identify the problem or problems to the patient and the parent, to offer hope and reassurance, outline treatment options and arrive at a mutually agreed-upon treatment plan. When depressed the teenager may not wish to participate actively in the treatment program, but without that treatment is pointless and ineffective. There are two main types of treatment: psychotherapy and medication. Sessions of family therapy may be required to deal with specific problems or issues. Other disorders may also be treated during this process; such as obsessive compulsive disorder, learning disability or attention deficit disorder. For the more serious and persistent depressions, particularly those with suicidal consequences at stake, medication is much more effective and actually necessary to maintain the proper chemical balance in the body. Teen Depression and Suicide :: Teenage Depression Depression has become a big issue among the adolescent world these days. It is something that is overlooked much of the time, and is often even hidden by other things. The suicide rate for teenagers has increased more than 200% over the last decade. Recent studies have shown that more than 20% of adolescents in the general population have emotional problems and 30% of adolescents attending psychiatric sessions suffer from depression. Maurice Blackman MB, FRCPC says that, â€Å"The majority of teenage depressions can be managed successfully by the primary care physician with support from the family.† Teens with psychiatric illness are 20 times more likely to die from accidents or suicide than adults Is depression in adolescents a significant problem? As in the afore stated paragraph a baffling 20% of adolescents in the general population have emotional problems! Despite this, depression in this age group is greatly under diagnosed, leading to serious difficulties in treatment of this issue. Adolescence is a time of emotional turmoil, mood instability, gloominess, great drama and heightened sensitivity. Possible suicidal thoughts can emerge from this troubled mind. Adolescent depression may present itself primarily as a behavior or conduct disorder, substance or alcohol abuse or as family turmoil and rebellion with no obvious symptoms normally associated with depression. Significant acute crisis in the teenager's life may also involve depression. Significant stresses include divorce, parent or family quarreling, physical or sexual abuse and alcohol or substance abuse. The teenager who exhibits signs of depression may be going through these tough situations. Teenagers can be oppositional and negative when depressed. If the teenager is an active participant in the treatment process than the physician will be able to identify the problem or problems to the patient and the parent, to offer hope and reassurance, outline treatment options and arrive at a mutually agreed-upon treatment plan. When depressed the teenager may not wish to participate actively in the treatment program, but without that treatment is pointless and ineffective. There are two main types of treatment: psychotherapy and medication. Sessions of family therapy may be required to deal with specific problems or issues. Other disorders may also be treated during this process; such as obsessive compulsive disorder, learning disability or attention deficit disorder. For the more serious and persistent depressions, particularly those with suicidal consequences at stake, medication is much more effective and actually necessary to maintain the proper chemical balance in the body.

Johann Ludwig Heinrich Julius Schliemann’s Excavation at Troy :: Anthropology

Johann Ludwig Heinrich Julius Schliemann’s Excavation at Troy Johann Ludwig Heinrich Julius Schliemann’s ability to challenge academic establishment make him an appealing yet dubious character. The German’s late nineteenth century excavations of Truva are often considered to have shed new light on ancient history or ‘undoubtedly destroyed a great deal of archaeological data that will forever be lost[1]. Despite the praise and glorification that surrounds the romantic stems of Schliemann’s work; his excavations have proved limited to the evolution of archaeology and ancient history. However some of Schliemann’s methodologies have often been considered significant in context to the evolution of both fields. His ‘great desire to affirm his hypotheses[2]’ has lead to important ancient historical data such as demonstrating Greek civilisation had commenced approximately one thousand years earlier then previous scholars estimated. Yet Schliemann’s excavations of Hissarlik are not completely revolutionary to the development of ancient history despite the modernisation of his primitive archaeological techniques and his ability to incorporate mythology in interpreting and formulating ancient history, while several contemporaries dismissed its credibility. Firstly Schliemann’s crude methodical techniques are not definitive in comparison to the works of other archaeologists such as, General Pitt Rivers. Secondly Schliemann’s discovery of an unknown civilization contributed to the broadening of ancient history. Moreover, Schliemann’s ability to see the great value of oral history and mythology has brought significant development to historical methodologies. Finally Schliemann’s flawed yet revealing archaeological techniques has allowed archaeology to improve, in learning from its mistakes. Firstly Schliemann’s contribution to the development of ancient history is limited in comparison to that of archaeological pioneers such as Pitt Rivers. Rivers, like Schliemann both avoided the stigma as ‘treasure hunters’ in their pursuit for knowledge of the antiquities. However Schliemann’s failure to seek perfection and accuracy questions his place in true archaeological circles. Historian Geoffrey Arnott comments, ‘the accuracy of his excavation reports can†¦be questioned, most seriously with regard to Troy.’ Schliemann’s primitive and simplistic techniques involving the destruction of various ruins do not deserve monumental credit. Historian Wellington King comments on the problematic nature of Schliemann’s excavations, Schliemann’s’ great desire to affirm his hypotheses to provide the evidence for the answers he created, is also his greatest weakness and shortcoming†¦he often conducted his archaeological work in a highly unethical manner, and a manner that could even compromise the archaeological integrity of his finds. In contrast, Rivers practised methods of perfection by comparing organic evolution to cultural development and developing future archaeological generic fundamentals such as ‘typology.’ ‘His purpose, therefore, was not concentrated on collecting artefacts solely for display, but in order to create a complex scheme of evidence to outline history.’[3] By contrast, men such as Pitt Rivers can be

Backstroke Swimming

Swimming backstroke the complete guide to getting your stroke perfect, along with faults their causes and how to Swimming backstroke/ introduction Swimming backstroke is the third fastest stroke competitively, originated from an old english style of swimming backstrokeand has developed over the years and has evolved into an alternating and more effective action. This action givesthe backstroke less resistance with a continuous propulsion.The speed of the backstroke is limited by the restrictiverange of movement of the shoulders as well as the ability/inability to use the power in the chest muscles to thebest desired effect by the roll of the body which will be discussed in more detail in the chapter about the upsweepof the arms. When swimming backstroke it is usually developed from a simple back paddle just kicking legs on the back, once this achieved then the backstroke swimmer can begin to develop the arms as long as the streamlined body position is maintained.Swimming backstroke c an be a first choice of stroke for the beginner because it free from the water and does not reallyrequire a breathing pattern so there are little or no difficulties. The only problem can occur is that some swimmersdo not like lying on their back due to fear of the water. Swimming backstroke/ body position When swimming backstroke the body should be in a flat and horizontal position (supine). The body should also be ina streamlined position. The head should be relaxed, with the water should be crossing the ears keeping steady andin line with the body.The eyes should be looking upwards and backwards keeping the chin close to the chest. Keep your shoulders just below the surface of the water but they will only become visible as your body rollsand your arms recover. Your hips are the lowest part of the body when swimming the backstroke. The practice ofletting the less able swimmers hips sink should be discouraged if you are teaching your child or yourself to swim backstroke Keep your le gs and toes close the surface with your toes breaking the surface of the water. Your body will roll on it'slongitudinal axis, you can roll up to about 60 degrees from the horizontal.This roll helps to assist so thatyou can place your hand in the best catch position so that you can have an effective underwater arm action which assists the over water arm recovery. The only part of the body not involved in this body roll is the head this should be perfectly still when swimming backstroke. Swimming backstroke/ leg action When you swim backstroke you will need a good, strong and efficient legs kick. The leg kick in backstroke is mainlyused for balance, it is not very likely that the leg kick will provide much propulsion.If you were a good leg kicker then you may get a little propulsion maybe 1-5 percent which could be used when the arms are not intheir propulsive phase. When one arm is above the head ready for entry and the other is by the side just finishedit's pull. You must remember t hat the although the legs do not contribute to propulsion they are still importantfor a good body position as well as balance for your strong sweeping actions made by your arms which is made outside the line of the body which will in effect will cause lateral deviation. So a good leg action willminimize lateral deviation (moving from side to side).Although the kicks are described as an upbeat and downbeat it is important that the kick does not necessarily take place in the vertical plane. Your hips move side to side along with the upper body as it rolls so the path of thekick is influenced at the time of the upbeat and downbeat. When swimming backstroke the legs action is alternating as well as continuous. Your legs will stay close togetherand the movement of each of your legs initiates from the hip and is observed as an upbeat and downbeat. Swimming backstroke/ Downbeat (recovery) Your leg will begin the downbeat close to the surface of the water and the leg is almost straight.When you begin thedownbeat your hip will press downwards and then will be followed by your upper leg your lower leg and your foot. The downbeat of each of your legs is called the recovery phase so this movement you will find should be relaxedand done without very much effort. When you get to the end of the downbeat that will be the lowest point and outside of your body range. The depth of this all depend on the size of your limbs. As a guide the leg will be at a point where the leg can be fully extended with your toes pointed. It will be apparent to the backstrokeswimmer that the flexibility of the your ankles is of importance.Swimming backstroke/ Upbeat (propulsion) The upbeat will begins as your hip begins to lift. Then your upper leg follows the hip and your knee will begin to bend your knee will bend will be about 90 to 120 degrees. Your lower leg will then press upwards with your shin andand the top of your foot. The pressure at this stage is a combination of upwards and backwards. Now your leg willaccelerate upwards and as you kick your leg to the surface this is when propulsion is achieved. When the toes breakthe surface the upbeat ends. Swimming backstroke/ arm actionWhen swimming backstroke you will find that the arms provide main propulsion. The arm action is continuous and alternating. There are four partsto the arms in backstroke which are the entry, catch, propulsive phase and recovery which I will discuss in moredetail. Swimming backstroke/ Entry When your hand enters the water your little finger enters first keeping it in line with your shoulder. Your palm facing outwards and then handshould sink to a depth of about 30 cms causing the minimum amount of drag. Make sure that your hand does sink a little because it help with your body roll.Your arm will also be fully extended As your hand will be placed in the water. Making sure it is donewithout any undue tension as well as making sure that you do not over reach. It is very important that the arm ente rs in line with the shoulder. An entry that is too close to the centre line or too wide will have a detrimental effect on your streamlining and propulsion. It is also very importantthat your little finger enters first by entering with the back of the hand will cause more resistance also you will not be able to sink your hand to the desired position as well as a tendency to pull with the little finger leading.Your hand will start to feel the pressure of the water ready for the sweeping and propulsive movement which will follow. Shortly afterwards your hand will be in the catch position. You will then rotate your hand downwards, as you press on the water your elbow will bend and your upper arm will rotate, givingyou a high elbow position that you need to enable the initial downward sweep to be performed effectively. When learning the backstroke you will find that the arms are the hardest part of the stroke and to develop the correct catch position and the downwards movement to the cat ch position.But practice makes perfect! Swimming backstroke/ Catch Your hand will now begin to give a backwards pressure on the water. This is so that your hand can make a purchase on the water and move your body forwards over the hand. Swimming backstroke/ downsweep Your elbow will now begin to bend and your hand will continue to sweep downwards slightly. As your hand begins the downsweep the pitch of your hand will be downwards as well as backwards. When you have finished the downsweep your elbow will be flexed to 90 degrees your hand will be in line with your shoulder. our elbow at this point will be pointing to the pool bottom and your finger tips should be facing outwards. You will change your hand pitchinto a backwards direction in the transition period, through to inwards and upwards, ready to begin your upsweep. Swimming backstroke/ Pitch of the hand It is important to realize that swimming backstroke you will continually alter the pitch of your hand throughout the sweeping actions. So that you get the best possible propulsion during the downsweep your hand should be pitched downwards, outwards, and slightly backwards.Swimming backstroke/ Upsweep Your hand will now sweep upwards towards the surface of the water keeping the elbow bent. The upsweep progresses from your shoulder line through to justabove the waist. It is of importance now that the roll is of great importance, to ensure that the sweeping propulsive can be effective. At the endof your upsweep your pitch is now altered to backwards then to downwards and then backwards. Swimming backstroke/ Final Downsweep When your hand sweeps downwards your elbow will straighten.The propulsive phase of the arm stroke is now completed with your arm extended below your hip. When you swim with the arms they are likened to a long letter ‘s' shape alongside your body in the water. Swimming backstroke/ Recovery Your body will roll after the final downsweep of your hand the recovery action of your arm begins . Your hand on which you are to recover will be below the level of your hip so it needs to be lifted through the water in a way which will cause you the minimum amount of resistance.You can achieve thisby rotating your hand inwards so the palm faces your thigh, your hand will then be able to cut through the water on its side. When you bring it up it should leave the water be thumb first. Once your arms have left the water your arms should come directly over your shoulder being an elevated positiondue to the body roll. When your thumb is your arms is gradually from your shoulder joint to place your hand in a little finger entry position as it passes yourhead on it's way down into the water.Make sure your arm is straight as wells relaxed during the recovery giving your arms an opportunity to recovery from thepropulsive phase. Make sure you do not overreach at this time. Swimming backstroke/ arm opposition When swimming backstroke the timing of the recovery and propulsive arm position is very important if you want to swim backstroke with good technique. As your recovering arm enters the water the propulsive arm should be sweeping down at the end of it's propulsive phase.The opposition of your arms helps with your body roll and your streamlining and it provides the most continuous application of propulsive force on the water. Swimming backstroke/ breathing When swimming backstroke breathing is not usually any problem because the head is free of the water and does not go into the water at any time. Breathing can take place at anytime during the stroke. Make sure that you take a regular pattern of breathing. The usual pattern of breathing isto take an in breath as one arm recovers and an out breath on the other arm recovery (in on one arm out on the other).Swimming backstroke/ co-ordination When swimming the backstroke there are two parts to co-ordination the timing the leg action with your arms as well as the arms with eachother. Swimming backstroke/ leg action tim ing The most common timing used is the six beat leg action this is complete by the time the cycle of the arms is complete. It is important that a strong balancing leg kick is used when swimming backstroke because as I mentioned before the arms are pitched outside the center line and the faster leg kick s used to maintain a streamline and horizontal position preventing lateral deviation (body moving side to side). The six beat action is the most commonly used a small minority of backstroke swimmers will use any other pattern. Swimming backstroke/ arm action timing When swimming backstroke your arms can be seen opposite each other but there is a period in this cycle when both arms are in the water at the same time. This is simply when one arm is moving towards the catch and the other is releasing the water and beginning the recovery.This is a slight overlap which ensures that your stroke doeskeep a continuous propulsion from your arms. Swimming backstroke/ faults, causes and correctio ns When you swim backstroke you will find you may have one or more faults, in this part of my page we will look at thefault that you may come across the reasons why and how you can improve and correct the fault. You may not realize youhave any kind of fault but it may be worth having a read in case you recognize something in your stroke which youmay not have realized is a fault.

Old Folks Home Essay

Sharks are a group of fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, andpectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term â€Å"shark† has also been used for extinct members of the subclassElasmobranchii outside the Selachimorpha, such as Cladoselache and Xenacanthus. Under this broader definition, the earliest known sharks date from more than 420 million years ago. Since then, sharks have diversified into over 470 species. They range in size from the small dwarf lanternshark(Etmopterus perryi), a deep sea species of only 17 centimetres (6.7 in) in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 metres (39 ft). Sharks are found in all seas and are common to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive in both seawater and freshwater.] They breathe through five to seven gill slits. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have several sets of replaceable teeth. Well-known species such as the great white shark, tiger shark, blue shark, mako shark, and the hammerhead shark areapex predators—organisms at the top of their underwater food chain Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species, which are variously called pufferfish, puffers, balloonfish, blowfish, bubblefish, globefish, swellfish,toadfish, toadies, honey toads, sugar toads, and sea squab.[1] They are morphologically similar to the closely relatedporcupinefish, which have large external spines (unlike the thinner, hidden spines of Tetraodontidae, which are only visible when the fish has puffed up). The scientific name refers to the four large teeth, fused into an upper and lower plate, which are used for crushing the shells of crustaceans and mollusks, their natural prey. Pufferfish are generally believed to be the second-most  poisonous vertebrates in the world, after the golden poison frog. Certain internal organs, such as liver, and sometimes the skin, contain tetrodotoxin and are highly toxic to most animals when eaten; nevertheless, the meat of some species is considered a delicacy in Japan (as æ ² ³Ã¨ ±Å¡, pronounced as fugu), Korea (as ë ³ µbok or ë ³ µÃ¬â€" ´ bogeo ), and China (as æ ² ³Ã¨ ±Å¡ hà ©tà ºn) when prepared by specifically trained chefs who know which part is safe to eat and in what quantity. The Tetraodontidae contain at least 120 species of puffers in 19 genera.[1] They are most diverse in the tropics, relatively uncommon in the temperate zone, and completely absent from cold waters. They are typically small to medium in size, although a few species can reach lengths of greater than 100 cm (39 in). The paradise fish, paradisefish, or paradise gourami, Macropodus opercularis, is a species of gourami found in most types of fresh water in East Asia, ranging from the Korean Peninsula to northern Vietnam. This species can reach a length of 6.7 cm (2.6 in), though most are only about 5.5 cm (2.2 in). Paradise gouramis were one of the first ornamental fish available to western aquarium keepers, having been imported toEurope as early as the 19th century. The paradise fish is one of the more aggressive members of its family. It is more aggressive than the three spot gourami, yet less pugnacious in nature than the less commonly kept combtail. Paradise fish are fairly combative, harassing and attacking each other, as well as potentially killing small fish. In the wild, they are predators, eating insects,invertebrates, and fish fry. The popularity of this species has waned in recent decades as much more colorful (and often less pugnacious) species of gouramishave become widely available to hobbyists. This species is one of the few fish that can change its color (lighter or darker) in response to stimuli. Eels are elongated fish, ranging in length from 5 cm (2.0 in) in the one-jawed eel (Monognathusahlstromi)[dubious – discuss] to 4 m (13 ft) in the slender giant moray.[2] Adults range in weight from 30 grams (1.1 oz) to well over 25 kilograms (55 lb). They possess no pelvic fins, and many species also lack pectoral fins. The dorsal and anal fins are fused with  the caudal or tail fin, forming a single ribbon running along much of the length of the animal. Most eels live in the shallow waters of the ocean and burrow into sand, mud, or amongst rocks. A majority of eel species are nocturnal, and thus are rarely seen. Sometimes they are seen living together in holes, or â€Å"eel pits†. Some species of eels also live in deeper water on the continental shelves and over the slopes deep as 4,000 m (13,000 ft). Only members of the Anguilla family regularly inhabit fresh water, but they too return to the sea to breed. Eels begin life as flat and transparent larvae, or leptocep hali. Eel larvae drift in the surface waters of the sea, feeding onmarine snow, small particles that float in the water. Eel larvae then metamorphose into glass eels and then becomeelvers before finally seeking out their juvenile and adult habitats. Freshwater elvers travel upstream and are forced to climb up obstructions, such as weirs, dam walls, and natural waterfalls. Lady Colin Campbell found, at Ballisodare, the eel fisheries were greatly improved by the hanging of loosely plaited grass ladders over barriers, enabling the elvers to ascend. The heaviest true eel is the European conger. The maximum size of this species has been reported as reaching a length of 3 m (10 ft) and a weight of 110 kg (240 lb). Other eels are longer but do not weigh as much, such as the slender giant moray which reaches 4 m (13 ft). The guppy (Poecilia reticulata), also known as million fish and rainbow fish,[1] is one of the world’s most widely distributed tropical fish, and one of the most popularfreshwater aquarium fish species. It is a member of the Poeciliidae family and, like all other members of the family, is live-bearing.[2] Guppies, whose natural range is in northeast South America, were introduced to many habitats and are now found all over the world. They are highly adaptable and thrive in many different environmental and ecological conditions.[3] Male guppies, which are smaller than females, have ornamental caudal and dorsal fins, while females are duller in colour. Wild guppies generally feed on a variety of food source including benthic algae and aquatic insectlarvae.[4] Guppies are used as a model organism in the field of ecology, evolution, and behavioural studies.[3] They are the most ferocious fish in the world. Even the most formidable fish, the sharks or the barracudas, usually attack things smaller than themselves. But the piranhas habitually attack things much larger than themselves. They will snap a finger off a hand incautiously trailed in the water; they mutilate swimmers—in every river town in Paraguay there are men who have been thus mutilated; they will rend and devour alive any wounded man or beast; for blood in the water excites them to madness. They will tear wounded wild fowl to pieces; and bite off the tails of big fish as they grow exhausted when fighting after being hooked. But the piranha is a short, deep-bodied fish, with a blunt face and a heavily undershot or projecting lower jaw which gapes widely. The razor-edged teeth are wedge-shaped like a shark’s, and the jaw muscles possess great power. The rabid, furious snaps drive the teeth through flesh and bone. The head with its short muzzle, staring malignant eyes, and gaping, cruelly armed jaws, is the embodiment of evil ferocity; and the actions of the fish exactly match its looks. I never witnessed an exhibition of such impotent, savage fury as was shown by the piranhas as they flapped on deck. When fresh from the water and thrown on the boards they uttered an extraordinary squealing sound. As they flapped about they bit with vicious eagerness at whatever presented itself. One of them flapped into a cloth and seized it with a bulldog grip. Another grasped one of its fellows; another snapped at a piece of wood, and left the teeth-marks deep therein. They are the pests of the waters, and it is necessary to be exceedingly cautious about either swimming or wading where they are found. If cattle are driven into, or of their own accord enter, the water, they are commonly not molested; but if by chance some unusually big or ferocious specimen of these fearsome fishes does bite an animal—taking off part of an ear, or perhaps of a teat from the udder of a cow—the blood brings up every member of the ravenous throng which is anywhere near, and unless the attacked animal can immediately make its escape from the water it is devoured alive.[28] A tuna is a saltwater finfish that belongs to the tribe Thunnini, a sub-grouping of the mackerel family (Scombridae) – which together with the tunas, also includes the bonitos, mackerels, and Spanish mackerels. Thunnini comprises fifteen species across five genera,[1] the sizes of which vary  greatly, ranging from the bullet tuna (max. length: 50 cm (1.6 ft), weight: 1.8 kg (4 lb)) up to theAtlantic bluefin tuna (max. length: 4.6 m (15 ft), weight: 684 kg (1,508 lb)). The bluefin averages 2 m (6.6 ft), and is believed to live for up to 50 years. Their circulatory and respiratory systems are unique among fish, enabling them to maintain a body temperature higher than the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish – the yellowfin tuna, for example, is capable of speeds of up to 75 km/h (47 mph).[2] Found in warm seas, it is extensively fished commercially and is popular as a game fish. As a result of over-fishing, stocks of some tuna species, such as the Southern bluefin tuna, have been reduced dangerously close to the point of extinction.[3] The hammerhead sharks are a group of sharks in the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a â€Å"hammer† shape called a â€Å"cephalofoil†. Most hammerhead species are placed in the genus Sphyrna while the winghead sharkis placed in its own genus, Eusphyra. Many not necessarily mutually exclusive functions have been proposed for the cephalofoil, including sensory reception, maneuvering, and prey manipulation. Hammerheads are found worldwide in warmer waters along coastlines and continental shelves. Unlike most sharks, hammerheads usually swim in schools during the day, becoming solitary hunters at night. Some of these schools can be found near Malpelo Island in Colombia, Cocos Island off Costa Rica, and near Molokai Island in Hawaii. Large schools are also seen in southern and eastern Africa. Starfish or sea stars are star-shaped echinoderms belonging to the classAsteroidea. Common usage frequently finds these names being also applied toophiuroids, which are correctly referred to as â€Å"brittle stars† or â€Å"basket stars†. About 1,500 species of starfish occur on the seabed in all the world’s oceans, from the tropics to frigid polar waters. They are found from the intertidal zonedown to abyssal depths, 6,000 m (20,000 ft) below the surface. Starfish are marine invertebrates. They typically have a central disc and five arms, though some species have more than this. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown. Starfish have tube feet operated by a hydraulic systemand a mouth at the centre of the oral or lower surface. They are opportunisticfeeders and are mostly predators on benthic invertebrates. Several species have specialized feeding behaviours including eversion of their stomachs andsuspension feeding. They have complex life cycles and can reproduce both sexually and asexually. Most can regenerate damaged parts or lost arms and they can shed arms as a means of defence. The Asteroidea occupy several significant ecological roles. Starfish, such as the ochre sea star (Pisaster ochraceus) and the reef sea star (Stichaster australis), have become widely known as examples of the keystone species concept in ecology. The tropicalcrown-of-thorns starfish (Acanthaster planci) is a voracious predator of coralthroughout the Indo-Pacific region, and the northern Pacific sea star is considered to be one of the world’s 100 worst invasive species. The fossil record for starfish is ancient, dating back to the Ordovician around 450 million years ago, but it is rather poor, as starfish tend to disintegrate after death. Only the ossicles and spines of the animal are likely to be preserved, making remains hard to locate. With their appealing symmetrical shape, starfish have played a part in literature, legend, design and popular culture. They are sometimes collected as curios, used in design or as logos, and in some cultures, despite possible toxicity, they are eaten.