Understanding The Bretton Woods System

Nations attempted to revive the gold standard following World War I, but it collapsed entirely during the Great Depression of the 1930s. Some economists said adherence to the gold standard had prevented monetary authorities from expanding the money supply rapidly enough to revive economic activity. In any event, representatives of most of the worlds leading nations met at Bretton Woods, New Hampshire, in 1944 to create a new international monetary system. Because the United States at the time accounted for over half of the worlds manufacturing capacity and held most of the worlds gold, the leaders decided to tie world currencies to the dollar, which, in turn, they agreed should be convertible into gold at $35 per ounce.​ Under the Bretton Woods system, central banks of countries other than the United States were given the task of maintaining fixed exchange rates between their currencies and the dollar. They did this by intervening in foreign exchange markets. If a countrys currency was too high relative to the dollar, its central bank would sell its currency in exchange for dollars, driving down the value of its currency. Conversely, if the value of a countrys money was too low, the country would buy its own currency, thereby driving up the price. The United States Abandons the Bretton Woods System The Bretton Woods system lasted until 1971. By that time, inflation in the United States and a growing American trade deficit were undermining the value of the dollar. Americans urged Germany and Japan, both of which had favorable payments balances, to appreciate their currencies. But those nations were reluctant to take that step, since raising the value of their currencies would increase prices for their goods and hurt their exports. Finally, the United States abandoned the fixed value of the dollar and allowed it to float—that is, to fluctuate against other currencies. The dollar promptly fell. World leaders sought to revive the Bretton Woods system with the so-called Smithsonian Agreement in 1971, but the effort failed. By 1973, the United States and other nations agreed to allow exchange rates to float. Economists call the resulting system a managed float regime, meaning that even though exchange rates for most currencies float, central banks still intervene to prevent sharp changes. As in 1971, countries with large trade surpluses often sell their own currencies in an effort to prevent them from appreciating (and thereby hurting exports). By the same token, countries with large deficits often buy their own currencies in order to prevent depreciation, which raises domestic prices. But there are limits to what can be accomplished through intervention, especially for countries with large trade deficits. Eventually, a country that intervenes to support its currency may deplete its international reserves, making it unable to continue buttressing the currency and potentially leaving it unable to meet its international obligations. This article is adapted from the book Outline of the U.S. Economy by Conte and Carr and has been adapted with permission from the U.S. Department of State.

Brave Incident - Free Essay Example

Sample details Pages: 1 Words: 386 Downloads: 7 Date added: 2017/09/12 Category Advertising Essay Did you like this example? High School Fight I went to high school in Vietnam; my cousin who I call brother went to the same high school with me. The high school I attended was also the school that many gang members attended. Those gang members always abused other students and took their lunch money as well as many of their valuables such as their wallets, cell phone and laptops. Our school principal always tried to inform the police about this behavior, but unfortunately that did not help. One day my class mate ran into the class room where I was spending my break, since I did not like to hang out in the play ground because of the gang members that were there, and he told me that my cousin was being harassed by a couple of those gang members and that they threatened to beat him to death if he does not give them all his money. My cousin was very stubborn much more like Victoriano. The two gang members had my cousin against the wall and were trying to steal his wallet and belonging while he fought them as much as he could. Don’t waste time! Our writers will create an original "Brave Incident" essay for you Create order I had nothing on my mind at that moment but to save my cousin and help him run away from those gang members. I looked for small pieces or rocks and a wooden stick and immediately ran towards my cousin screaming loudly so that I can distract them from him. As I started throwing the rocks on them they let go of my cousin and paid attention to where I was heading which was directly towards them. I screamed loudly telling my cousin to run away and go to the principal’s office just like when Dona Guadalupe told her cousin â€Å"I am not cutting you free so you can be brave and get killed. I want you running so you can live† I wanted my cousin to run and not try to fight the gang members when they let go of him. My cousin ran to the principal’s office while I threw the stick of wood towards them. I immediately changed my direction and ran towards the principal’s office as well. The Principal called the police and they arrested the gang members and I was able to save my cousin after all.

Reducing Overall Costs Through School And District...

As cuts to educational funding continue, the question of lowering overall costs through school and district consolidation emerges at all levels. Arguments for consolation, which merges districts and consolidates their management, rest primarily on two presumed benefits: (1) fiscal efficiency and (2) higher educational quality. However, a review of current research evidence suggests that after a century of consolidation, most fiscal or educational efficiencies have been realized by the system (Howley, Johnson Petric, 2011). Furthermore, mandated consolidation directives may actually lead to adverse impacts and, while serving a public relations purpose in a time of crisis, are unlikely to be a reliable way to obtain substantive fiscal or†¦show more content†¦With this, mandates and community desires place pressure on the allocation of personnel across the district. The economy of size allows larger districts to employ more specialized teachers, putting them in a better positi on to provide a wide range of courses required by state and federal mandates and expected by today’s students and parents. This ability allows for more individualized instruction – by age level, subject level, and level of ability. For example, hiring a full time instrumental music teacher, offering a wider variety of world language courses, or creating specialized special education centers. Personnel in larger systems also often enjoy improved professional development, increased salaries and benefits, and greater job security. With more colleagues, teachers in larger districts benefit from professional learning communities upon which to draw for advice and discussions, interactions that lead to improved effectiveness. Considerations Consolidation factors may also come at an expense. Fiscally, districts undergoing consolidation often face ongoing and preliminary transitional costs. Operating and capital expense often shift upward at the time of consolidation due to facilities adjustments and potential new construction. Additionally, average transportations distances increase, resulting in a rise in the district’s transportation spending per pupil. Personnel expense may also escalate due toShow MoreRelatedThe Property Assessment System2309 Words   |  10 Pagesresult in a reduction of $4.4 million dollars in overall county-wide costs. This reduction in costs would eliminate the 18 local assessment offices spread throughout Lake County and only provided for one assessment office in Waukegan. The initial study by Lake County contained factual errors, an underrepresentation of the personnel required and acknowledged that taxpayer access would be limited with fewer locations, but failed to include the additio nal costs of satellite locations in their study. ThisRead MoreRoad Transport11468 Words   |  46 PagesNATIONAL ROAD TRANSPORT POLICY Introduction 1.1 Road transport is vital to economic development, trade and social integration, which rely on the conveyance of both people and goods. Reduction in transport costs promote specialization, extend markets and thereby enable exploitation of the economies of scale. Global competition has made the existence of efficient transport and logistic systems in delivery chain an absolute imperative. Easy accessibility, flexibility of operations, door-to-door serviceRead Moreeasyjet Essay12067 Words   |  49 PagesAirports...................................................................................................................... 23 3.2.1 Secondary Airports in Closer Proximity to the Primary Ones .............................................. 23 3.2.2 Cost savings in Airport Charges............................................................................................ 24 3.2.3 Competitors’ Presence and Analysis in Suggested Airports ................................................ 27 3.2.4 PassengerRead MoreJames Finlays Attachment8695 Words   |  35 PagesSouthern Rift valley, Kericho District, six kilometers eastwards from Kericho town. I was Offered a placement at finance Department (Leaf Tea accounts),for a period of three month my Host supervisor Being Rose Koech holding a position of senior Assistant Accountant. CHAPTER ONE: 1.1 BACKGROUND INFORMATION The Swire group. John Swire and sons Limited, with its headquarters in London is Swires’ Parent Company. John Swire sons limited through James Finlay, has substantialRead MoreBusiness Plan of Skytrails Airline, Ltd.14517 Words   |  59 Pagesserves the North Atlantic route from Stansted, SkyTrails will be uniquely positioned to take advantage of the unserved demand that exists. Stansted is the fastest growing airport in Europe with 9.9 million passengers for 1999.It is the hub of low cost airlines Go Fly, Ryanair, and Buzz, all of which are experiencing tremendous growth and an increase in business travellers. They claim that as many as 40 percent of their passengers are travelling on business. Stansted benefits from an Open SkiesRead MoreInformal Organization Marketing : Presentation3305 Words   |  14 Pagespublicizing in the space of web systems administration these real contemplations ought to be taken after. It is likely the fundamental promoting stage that stimulates nitwit confirmation correspondence and obligation among merchants and moreover buyers. Overall associations have seen Social Network Marketing as a potential showcasing stage, utilized them with improvements to control their advancing campaign with casual group publicizing. Casual group promoting uses internet organizing for doing the businessRead MoreUniqlo Annual Report21563 Words   |  87 Pagesanywhere, everyday. This basic concept has guided our actions since the birth of our very first store. When UNIQLO first opened its doors in a corner of a busy shopping district in central Hiroshima on June 2, 1984, it was six o’clock in the morning! The store opened early in the morning so that people could shop before going to work or school. To encourage people to drop in and browse around as they would in a bookshop or music store, we devised a store layout with the casual atmosphere of a warehouseRead MoreProject Report on Employee Attrition14600 Words   |  59 Pagesvaluable information provided by him on the current trends in the industry. I wish to thank our Principal Dr. N. S. Malavalli for his encouragement and support. Ponnappa I.S 5 CONTENT PAGES EXECUTIVE SUMMARY INTRODUCTION WHAT IS ATTRITION? THE COST OF ATTRITION TRACKING ATTRITION CAUSES CURBING ATTRITION SUGGESTIONS IMPORTANCE OF EMPLOYEE ATTRITION LOOPHOLES IN ATTRITION MANAGEMENT EFFECTIVE ATTRITION MANAGEMENT ANNEXURE BIBLIOGRAPHY 1-2 3-6 7-14 15-19 20-39 40-41 42-60 61-65 66-69 70-78 79-82Read MoreA Research On Social Network Marketing3376 Words   |  14 Pagespublicizing in the space of web systems administration these real contemplations ought to be taken after. It is likely the fundamental promoting stage that stimulates nitwit confirmation correspondence and obligation among merchants and moreover buyers. Overall associations have seen Social Network Marketing as a potential showcasing stage, utilized them with improvements to control their advancing campaign with casual group publicizing. (Sisira, 2011) Casual group promoting uses internet organizing forRead MoreChaos in the Skies5932 Words   |  24 Pages2002, p. 1A.1 1 A. Levin, M. Adams and B. Morrison, ‘Four hours of fear: decision-making in a crisis’, USA Today, 12 August 2002, p. 1A. This case study was written by Professor Gary J. Stockport and MBA student, Norman Roberts, Graduate School of Management, University of Western Australia, Perth, Australia. It is intended as a basis for classroom discussion and not as an illustration of either good or bad management. This case was prepared entirely from published sources.  © Gary J. Stockport

Someone in the Backseat- Creative Writing Essay - 690 Words

Driving through torrential rain was very torturous. The rain thumped on the bonnet and the wind whistled along the curves of the car. The trees were waving frantically in the wind as if to attract the attention of passing cars. Like the night, the winding country road grew longer and longer, darker and darker with every passing hour. The bright headlights pushed back the darkness, which immediately returned to haunt the rear of the car. The darkness seeps into the car and hangs heavily over the back seat. Twenty one year old Natalie had just passed her driving test and this was the first time she was driving back from university by herself. Natalie was quiet relaxed driving through the night,†¦show more content†¦Ã¢â‚¬Å"Bang† the tyre bursts as the car hit the kerb. She slams on the brake and stops the car. Natalie, scared of the thought of getting out of the car to fix the tyre, switches off her phone and decides to continue until she finds a garage. After approximately fifteen minutes of slow careful driving Natalie comes across a secluded garage. She stops the car in the garage yard and notices a light coming from a shack in one corner of the yard. Natalie winds down her window and shouts for attention in the direction of the shack. No reply. Natalie puts on her coat and gloves and gets out of the car. The yard is wet and muddy and she notices numerous dark cabins lining the yard. She goes over to the cabin with the light on and knocks on the door. No answer. She bangs harder with the bottom of her fist. Again no answer. She tries the handle. There is a â€Å"click† and the door opens slightly. â€Å"Hello, hello, is anybody there†? No reply. She pushes the door wide open. The door opens with the most painful creaking sound. Natalie steps into the room and the overpowering damp smell forces her to immediately put her hands over her mouth and nose. The inside of the cabin was bigger than it looked from the outside. There was a single dirty lightbulb hanging low from the ceiling. The stale atmosphere seemed to discolour everything in the room. An even dirtierShow MoreRelatedThe 17 Essential Qualities of a Team Player1447 Words   |  6 Pagesthe big picture, relational, focused on others, selfless, willing to take a backseat for the good of the team, and tenacious - works hard to overcome obstacles, no matter what. U U 1. Adaptable: If you wont change for the team, the team may change you. Team players who are most likely to become adaptable possess the following characteristics: a) they are highly teachable; b) they are emotionally secure; c) they are creative; and, d) they are service-minded individuals. To achieve such characteristicRead MoreReviewer in English Iv Nat5930 Words   |  24 Pageswhen the crime was committed. Mechanics make inferences when they run diagnostics, tinker around in the engine, and chat with you about how your car is acting to figure out whats wrong under the hood. Likewise, you infer things all the time. If someone stares angrily at you from the rearview mirror and mimics yelling when youre stopped behind them at a red light, you might come to the conclusion that youve offended him or her while driving in some way. If a woman is pushing a covered strollerRead MoreDeveloping Management Skills404131 Words   |  1617 PagesDiagnostic Surveys for Creative Problem Solving 168 Problem Solving, Creativity, and Innovation 168 How Creative Are You ? 169 Innovative Attitude Scale 171 Creative Style Assessment 172 SKILL LEARNING 174 Problem Solving, Creativity, and Innovation 174 Steps in Analytical Problem Solving 174 Defining the Problem 174 Generating Alternatives 176 Evaluating Alternatives 176 Implementing the Solution 177 Limitations of the Analytical Problem-Solving Model 178 Impediments to Creative Problem Solving 178Read MoreGp Essay Mainpoints24643 Words   |  99 Pagesprofessional journalists (compared to citizen journalism) – conte nt quality †¢ Citizen journalist â€Å"on-the ground† reports vs. professional whose sole purpose is to uncover each and every piece of information related to the news article they are writing †¢ Wider and deeper coverage †¢ Connections to a wider spectrum of professionals ( greater insight into issue at hand †¢ E.g. 2008 U.S. Presidential Elections (bloggers provide personal opinions about who was likely to win but New York TimesRead MoreA Critical Review of â€Å"the Ambiguities of Football, Politics, Culture, and Social Transformation in Latin America† by Tamir Bar-on.14147 Words   |  57 Pagesrefers to a variety of research techniques that make use of already existing sources, or publicly accessible information and data. This method is not the most effective research method in the sense that when a researcher relies on data collected by someone else, chances are he will not find exactly what is needed. The author uses research performed by noted sociologists and sources that are credible and trustworthy. He includes links to the journals in which he collected his data from by hyperRead MoreHbr When Your Core Business Is Dying74686 Words   |  299 Pagesyour boss, he said, † â€Å"here are eight behaviors I would expect of you. Then he † went on, â€Å"And here is what I think you should expect from your leader. I’ve never seen a group of executives react as we did. † Every one of us bent over our notebooks, writing furiously, as if a professor had said, â€Å"Here is what will be on the exam; you might want to write it down. † A couple of days later, I wrote Larry and suggested we develop his talk into an article. He said yes; senior editor Ellen Peebles said yes

Military strategist and conflict Free Essays

Roman versus Medieval Armies Comparing Roman and Medieval Anglo-Saxon armies posit certain novel challenges due to evolutionary changes in military techniques and strategy and the huge time gap of around two thousand years that separated them. For the purpose of study here, we will take into account the military strategy and style deployed by Roman armies of 200 BC, at a time when they constituted most overwhelming military force in the contemporary world and compare them with strategy, styles, techniques used by 13th century Medieval armies of England, France and Saxony. The Roman military strategies of warfare were based on traditions and experience that ran since more than 500 years, evolved through countless campaigns and wars. We will write a custom essay sample on Military strategist and conflict or any similar topic only for you Order Now Their beginning was humble, in form of a local armed tribe set to protect its geographical entity. However, over next centuries they acquired as they acquired skills and experience, they molded themselves in a massive invincible army that was reputed even among its enemies for its technical superiority and tenacity. Army layout: Roman army presented a fully hierarchical structure, like a modern day military, composed of various units and sub-units. Legions marked the largest and fundamental mass units of army with their strength totaling around 6000 men. Each legion was divided in cohorts   that were further subdivided in smaller units of maniples and centuries that comprised 100 soldiers on average. The legions stationed at front contained exclusively heavy infantry, comprising best and most skilled soldiers of the army. On any campaign the army moved through its legions and each of them were responsible for marching, encampment, logistics, and vigilance according to set standards of the army. Warfare strategy: Romans used numerous innovative and unique models within the scope of their traditional model of conducting warfare in triple lines. Hastati formed the first rank, placed closest to enemy lines, principes formed second line and triarii was the last rank that was typically kept as specialist reserved force. The army structure at battlefields was remarkably ordered, with frontline and rear units regularly placed in a way so as to leave no gap in the ranks. The three line system of Roman army provided it crucial maneuvering space, gave it depth and allowed it to bear initial losses to overcome them in later phase of battle. Warfare tactics: The actual combat involved hand to hand battles, shock battles and use of war machinery that threw arrows, stones and fireballs as missiles to enemy army lines. Usually the attack was initiated by Roman war machines where they barraged d opposing army with arrows, spears, and heavy stones. Subsequent to this, heavy infantry was first unit to enter main battle foray and engaged opposition soldiers through hand to hand combat. As fighting units were progressively injured and worn out, they withdrew back into the cushion of three tier structure and they were replaced by fresh units to continue battle. Cavalry was largely used for ornamental warfare, were limited in number and did not take extensive partake in warfare. Logistics: Supplying the army with food and other needs was a major challenge for Roman generals, specially on their long campaigns and given the fact that food production and methods of supplies were very nominal in ancient times. Therefore Roman troops carried most of equipment, including their lodging, clothing on animal carts. Their efficient network meanwhile ensured continued supplies of food and fuel to keep army moving. Compared to ancient Roman military system, the medieval warfare presents significant contrasts, especially in terms of military deployment, strategy and battle tactics. Use of gunpowder and missile technology identified the greatest departure from conventional and largely manual methods of conducting war. The rise of pillage warfare, where armies of one state looted and pillaged other states for purpose of supplies led rise to fortification and siege warfare Army Layout: Medieval army layout deployed long range heavy and light canons in the front line, supported by archers and heavy cavalry that formed main mass of army. Cavalry formed the main fighting force of the army, that comprised men mounted on horses, ready to give charge to enemy flanks. Knights, mounted soldiers with special military training formed an important part of cavalry ranks. Warfare Tactics: Medieval warfare tactics employed extensive use of canons and, towards later age, use of guns to start the first volley of assault. This was followed by charge of cavalry units. Use of horses had given lightening striking potentials to European armies and they used this advantage to launch rapid waves of attacks. In the medieval warfare, role of infantry had been relatively marginalized and their prime purpose was to act as support units at times of large scale siege and inundation of enemy fortification Battle of Cannae Battle of Cannae is considered one of most important ancient military events that is still widely studied and taught in military schools. The battle was part of second Punic war, and it was fought under Carthaginian Hannibal against the might of Roman Empire in 216 century BC. The Roman army was numerically much more superior and had better terrain than army of Hannibal and had enough time to prepare for the oncoming battle. Yet, Hannibal successfully overwhelmed the opposition and handed one of most comprehensive defeat to Roman army in its heydays. The combined Roman and Carthaginian forces combating in battle exceeded 1,40,000: Romans at near 850000, and Carthaginian forces totaling 55000. On the day of battle, Roman generals arranged their army in traditional three rank structure, with infantry placed in center and cavalry placed at side flanks to provide cover. The arrangement displayed traditional Roman affinity for depth, and they planned to use their deployment to cut through center of Hannibal’s forces.   However, the fact that Roman generals had opted for depth, rather than width meant that both armies same frontal appearance, negating the visual aspect of Roman numerical strength. The armies of Hannibal were also at apparent disadvantage with Aufidus River cutting off their chances of Retreat. The entire strategy of Roman generals was based on their previous experience of skirmishes and combats with Hannibal, whom they knew to be a resourceful, and cunning tactician. Hannibal was also ware of weaknesses of his army and the fact that both armies were meeting in open battlefield did not provide him to plan for any possible ambush or surprise maneuver. But Hannibal was also well aware of strengths and weaknesses of his different units and he deployed them strategically at flanks to make their best use. The Roman army moved forward en masse while Hannibal extended his army in line formation providing greater flexibility and inner movement within army flanks.Hannibal used his superior cavalry to defeat and push behind inferior Roman cavalry and then outflank them to attack Roman rear. The pincer movement created panic in Roman flanks and their front lines started to fall on back lines where Carthaginian cavaliers eliminated them. This caused the rear lines to push towards center, creating massive confusion among Roman soldiers. The combined Roman push towards their own center allowed created a situation where they got extremely densely packed, not even leaving them sufficient them to reform, regroup or maneuver their weapons. Meanwhile Carthaginian army had completely encircled Roman forces, and started cutting them down to virtually last man. The battle is still recounted as one with highest number of causalities in a single day. A number of factors contributed to victory of Hannibal, including his superior analysis of situation and his clever use of cavalry and infantry. Hannibal converted the disadvantage of having a river at back to advantage in pushing ahead his forces with full knowledge that Romans could not at least outflank his infantry. Meanwhile, Roman army could retreat through only its left flank, its other retreating chances cut off by Mountains at one side and River at other. Ultimately Romans were left with no chance to escape and Hannibal accomplished one of the greatest military feat in history. Reference Richard A. Gabriel. Donald W. Boose Jr.1994.   The Great Battles of Antiquity: A Strategic and Tactical Guide to Great Battles That Shaped the Development of War. Greenwood Press. Westport, CT. John France. 1999. Western Warfare in the Age of the Crusades, 1000-1300.   . UCL Press. London. Richard A. Preston, Sydney F. Wise, Herman O. Werner. 1956. History of Warfare and Its Interrelationships with Western Society. Frederick A. Praeger.: New York. Roger Beaumont . 1994. War, Chaos and History. Praeger. Place of Publication: Westport, CT. How to cite Military strategist and conflict, Essay examples

Taxation Law of Australia Business Entities

Question: Describe about the Taxation Law of Australia for Business Entities. Answer: The current study focuses on the assessment of the income tax that can help in calculation of the residential standing of Juliette. The first question in the current study deals with the residential status of Juliette and it suggests that the Juliette will be held as the resident of Australia enumerated from the perspectives of the income taxes between the period 2014 and 2016. The present study also takes into account different years for addressing the year in which the income was earned. The following year have the need for preparation of financial statements for building up taxable income generating out of particular rental property. In the subsequent section, the current study elucidates in detail the components of rented property along with appropriate justification. 1: Current Condition of Juliette: As per the section 3 to 5 under the Income Tax Act during the year 1997, each individual along with other business entities as well as other companies need to make payments for the income taxes for each financial year. In accordance with the Australian Law, the Income tax Assessment Act starts from the 1st July till 30th June of the subsequent year (Inheriting a dwelling | Australian Taxation Office., 2016). As such, the residential status of Juliette primarily affects the liability tax of different individuals of different individual entities that in turn determine the residential status of different individuals. As per section 6 stipulated under the Income Tax Assessment Act, the tax payer can be classified as a resident of Australia and the foreign resident from the perspective of tax (Investment income | Australian Taxation Office., 2016). According to the present Act, the resident of Australia is referred to as an individual who can be considered as a resident of Australia mainl y for the purpose of tax. As mentioned in the section 6-5 (2) along with section 10(5), the individuals who cannot be considered as residents as per the Income tax Act can be regarded as foreign residents (Investment income | Australian Taxation Office., 2016). In other words, it can be said that an individual can be considered as a resident of Australia in case if the specific individual can satisfy at least one out of the four evaluation tests according to the Income Assessment Act under the section 6 (1). The tests include the following: Primary test regarding residency or in other words Ordinary Residency Test Ordinary Residency Test primarily suggests that the residential status of a specific individual is founded on simple ideas and concepts. The guiding principle mentions that a particular individual will remain a resident in case when the taxpayer resides in and out of the Australia. The status of residency can be primarily determined on a yearly basis and the taxpayer might possibly be the resident for the remaining part of the year. Under the regulations stated under the Australia Tax Offices Tax rule 98/17, there are certain factors that can act as a guide for determination of status of ordinary residency Residency (the resides test | Australian Taxation Office., 2016). This includes certain important factors such the nationality of the individual, social and at the same time, the family tie up, rules as well as regulations regarding the physical presence both in as well as out of Australia. Another significant factor of the ordinary residency test comprises of the assessment of the nature of the travel to abroad and evaluation of the permanent or else the temporary nature of stay. In addition to this, the important factors include the regularity, duration, and frequency of the visits. Furthermore, the stratagems for maintenance of the place of residence both in as well as around Australia are an important factor that needs to be taken into consideration for the purpose of evaluation of the ordinary residency test Residency ( the resides test | Australian Taxation Office., 2016). Domicile Test The domicile test primarily provides essential facts concerning a particular individual for taking into account the particular person as resident for the purpose of tax in case if the payer of the tax is residing in Australia as conditioned under section 6(2) (a)(i) Residency (the domicile test | Australian Taxation Office., 2016). Again, the particular regulation mentions that a particular citizen of Australia can be mechanically regarded as the resident of Australia from the perspective of tax. 183- day test The 183 day test can be considered to be one of the secondary statutory tests. Again, the particular process of scrutiny suggests that a payer of tax can be regarded as resident if and only if the residents actually reside in Australia for more than the specified 183 days according to the conditions stated under the section 6(1) (a) (i). Again, if the payer of the tax generally resides both in and outside the Australia and there can be individuals who do not intend to stay in the Australia for more than 183 days Residency (the 183 day test | Australian Taxation Office., 2016). In both the above-mentioned case, if the individual inhabits in Australia for more than 183 days, the payers of the tax can be regarded as the resident from the point of view of taxation. In particular, the present test is applicable in Australia for greater than one income year. The present test can also be regarded as a statutory test that has the need for the maintenance of abode both in as well as outside A ustralia. The test also calls for the need of staying as a permanent resident in a specific income year for more than 183 days. However, the duration of the stay of the resident might not be continuous and it does not require continuous stay for 183 days Residency (the 183 day test | Australian Taxation Office., 2016). In all the 183 days, the individual needs to be physically present in Australia during the specific income year. Therefore, it is imperative to understand the process of application of the 183-day test for assessing the nature of residency during a particular income year. Superannuation Test Superannuation test is a statutory test that can review the statutory test for assessment of the residency status of individual in the nation Australia (Sharkey, 2015). The specific test needs to cover different current Commonwealth Government members of the staff Work out your (tax residency | Australian Taxation Office., 2016). The rule also states that in case if payer of tax is not a member of the superannuation fund, then in that case the particular person fails in meeting the requirements of the superannuation test. Residential Status of Juliette during the year 2014 and 2015: Juliette entered into an agreement with the American theatre company with the intention and purpose of offering her service in Australia for 2 years that essentially starts from 15-03-2015 to 15-03-2017. Residential Status of Juliette for 2015-16:- The residential tests that can be conducted for the purpose of determination of residential status of Juliette during the particular financial year 2015-16 include the following: The Reside Test:- For the duration of the taxation year (2014-15), Juliette had the purpose and intent to reside in Australia for around 2 years primarily. However, after the marriage the Juliette intends to stay in Australia for her remaining life (Rental properties - claiming capital works deductions | Australian Taxation Office., 2016) Juliettes mother has her family member who expired during the present year. Right after her mother, the closest family member of Juliette is Juliettes husband, who has taken birth in and resides in Australia Residency (the resides test | Australian Taxation Office., 2016). Juliette had different business tie ups in the nation Australia during the period of travel in the year 2014 and 2015. Juliette had a flat in lease to reside for the duration of two years in Australia and thereafter Juliette acquired the home for permanent stay (Rental properties - claiming repairs and maintenance expenses | Australian Taxation Office. 2016). During her stay in Australia in 2015-16, she used to maintain a routine life. Juliette used to maintain a good life during Juliettes stay in Australia during the period 2015 and 2016 (Rental property expenses | Australian Taxation Office., 2016). Domicile Test:- Juliette has taken birth in Britain. Therefore, Juliette can be considered British By birth Residency (the domicile test | Australian Taxation Office. 2016). By her own intention and choice, Juliette intends to reside in Australia permanently (Work out your tax residency | Australian Taxation Office., 2016). Again, by the guidelines of the tax law, Juliette can be considered to be married to a resident of Australia (Rental property expenses | Australian Taxation Office., 2016). 183 Days Test:- The usual place of residence of Juliette is England. However, she had purchased the residence in Australia Residency (the 183 day test | Australian Taxation Office. 2016). Enumeration of the total number of days Juliette stay in Australia Period No. of Days in Australia No. of Days in England 1st July'15 - 15th October'15 107 0 16th October'15 - 14th April'16 0 181 15th April'16 - 30th June'16 76 0 TOTAL No. of DAYS 183 181 Superannuation Test:- The employers of Juliette are citizens of America, for that reason, Juliette can be considered under the system of superannuation. As mentioned in the current case study, Juliette and her husband can be considered under the superannuation system. According to the results of the above test, it is apparent that Juliette has successfully qualified in different test including the Superannuation test. As a result, consistent with the subsection 6(1) of The Income Tax Assessment Act, 1936 Juliette can be regarded as a resident of Australia in the year 2015-16. 2 (a): Taxpayee : Mr.George Statement of Taxable Income from Rental Property:- For the period ending on 30th June,2016 Particulars Amount Amount Assessable Income: Rent from Property 13900 Total Income from Rental Property 13900 Deductible Expenses: Commission to Agent 695 General Repairs Maintenance 6000 Repainting of Front Fence 2500 Fixing of broken front door 1000 Capital Work Deduction : Replacing of Damaged Roofs 15000 15000 Deduction Rate 2.5% p.a. Deduction for Capital Work 219 Depreciation on Assets 1019 Total Deductible Expenses 11433 Net Income from Rental Property 2467 Working: Calculation of Depreciation:- Items Cost Effective Life Depreciation Rate p.a. Useful Days Depreciation Hot Water Service 2000 12 100% 365 167 Carpets 3500 10 100% 365 350 Existing Furniture Fittings 5000 13.33 100% 365 375 New Furniture Fittings 1200 13.33 100% 213 53 Stove 900 12 100% 365 75 Total Depreciation 1019 2 (b): The enumeration of the rental income of George for the purpose of taxation is primarily founded on different guiding principles and suppositions of tax: George is regarded to be a resident of Australia for the purpose of taxation during the financial year 2015-16. George also had received the property at birth. George started utilization of the property after the inheritance of the property that has led to the generation of incomes for a period greater than 2 years. For that reason, George cannot assert for any kind of exemption regarding the rental income (Saad, 2014). The income generated from the rent of a specific property needs to be located in Australia. Therefore, the rental income is arising out of the property located in Australia. In that case the rental income from the property is completely taxable under the tax laws ("Investment income | Australian Taxation Office", 2016). The agents are well paid for the purpose of generation of the rental income arising out of the property. Therefore, consistent with the Sect 8.1 of ITAA 1997, this can be regarded as a deductible expenditure from the rental income ("Rental property expenses | Australian Taxation Office", 2016). The common repairs are supposed to be carried out for the purpose of wear and tear as well as other harm from renting out the definite property. The preservation works can be carried out by maintaining the property in a rentable state. Based on the suppositions, the specific expenses for the general repairs as well as maintenance can be regarded as deductible expense ("Rental properties - claiming repairs and maintenance expenses | Australian Taxation Office", 2016). The process of replacement of the damaged roof of the particular property can be considered a substantial enhancement of the property. Therefore, the expenses incurred for the improved of the property can be considered as a capital expenditure (Norregaard, 2013). For that reason, the expenditure, 2.5% of the overall expenses can be included in the overall deductible expenditure. Therefore, George can get pleasure from different deductions for the upcoming 40 years in compliance to the Sect 40 (I) of ITAA 1997 ("Rental properties - claiming capital works deductions | Australian Taxation Office", 2016). The acquirement of new furniture, fittings cannot be considered as repairs maintenance expenses as slated under the section 26 of ITAA 1997 (McKerchar et al., 2013). However, the new furniture as well as fittings can be considered as assets and George is normally permitted to deduct the amount of depreciation on different assets generated out of the rental income in the present year ( McKerchar et al., 2013). The purpose of repainting of fence and fixing of doors can be considered as expenses that can be incurred for maintaining the property in a proper rentable condition. For that reason, the present expense can be regarded as the deductible expense according to rules slated under Sect 40 (G) of ITAA 1997. As per tax rules and regulations, it can be primarily supposed that the particular assets, barring the new furniture as well as fittings, are acquired after 1st July, 2004. Seeing that George follows prime-cost technique for depreciation, the assets are essentially depreciated at the rate of 100%, counting the new assets in accordance to the rules mentioned under the Sect 40 (B) of ITAA 1997 ("Rental property expenses | Australian Taxation Office", 2016). According to different assumptions as well as taxation rules, it can be hereby ascertained that the total rental income is $13900 and the overall deductible expenses amounts to around $11433. Therefore, the net income that can be assessed for the present financial year is $2467. References Inheriting a dwelling | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/General/Capital-gains-tax/In-detail/Gifts,-inheritances-and-deceased-estates/Inheriting-a-dwelling/ Investment income | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/individuals/income-and-deductions/income-you-must-declare/investment-income/#Rent1 Rental properties - claiming capital works deductions | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/General/Property/In-detail/Rental-properties/Rental-properties---claiming-capital-works-deductions/ Rental properties - claiming repairs and maintenance expenses | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/General/Property/In-detail/Rental-properties/Rental-properties---claiming-repairs-and-maintenance-expenses/ Rental property expenses | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/individuals/income-and-deductions/in-detail/investments,-including-rental-properties/rental-property-expenses/ Rental property expenses | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/individuals/income-and-deductions/in-detail/investments,-including-rental-properties/rental-property-expenses/?page=3#Deduction_for_decline_in_value_of_depreciating_assets Residency - the 183 day test | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/Individuals/International-tax-for-individuals/In-detail/Residency/Residency---the-183-day-test/ Residency - the domicile test | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/Individuals/International-tax-for-individuals/In-detail/Residency/Residency---the-domicile-test/ Residency - the resides test | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/individuals/international-tax-for-individuals/in-detail/residency/residency---the-resides-test/ Work out your tax residency | Australian Taxation Office. (2016).Ato.gov.au. Retrieved 11 August 2016, from https://www.ato.gov.au/Individuals/International-tax-for-individuals/Work-out-your-tax-residency/#ExampleAustralianResident McKerchar, M., Bloomquist, K., Pope, J. (2013). Indicators of tax morale: an exploratory study.eJournal of Tax Research,11(1), 5. Norregaard, M. J. (2013). Taxing Immovable Property Revenue Potential and Implementation Challenges (No. 13-129). International Monetary Fund. Saad, N. (2014). Tax knowledge, tax complexity and tax compliance: Taxpayers view.Procedia-Social and Behavioral Sciences,109, 1069-1075. Sharkey, N. (2015). Coming to Australia: Cross border and Australian income tax complexities with a focus on dual residence and DTAs and those from China, Singapore and Hong Kong-Part 1.Brief,42(10), 10.

Biology Aqa free essay sample

16. 8 – Genetic fingerprinting43 Section 9. 1 – Sensory Reception †¢ A stimulus is a detectable change in the internal or external environment of an organism that produces a response. The ability to respond to a stimulus increases an organism’s chances of survival. †¢ Receptors transfer the energy of a stimulus into a form that can be processed by the organism and leads to a response. †¢ The response is carried out by â€Å"effectors† which can include cells, tissues, organs and systems. Taxis – A simple response that’s direction is determined by the direction of the stimulus An organism can respond directly to a change in the environment by moving its body either: 1. Toward the stimulus (positive taxis) 2. Away from the stimulus (negative taxis) Kinesis – Results in an increase of random movements †¢ Organism does not move towards/away from the stimulus †¢ The more intense the stimulus the more rapid the movements †¢ Kinesis is important when the stimulus is less directional such as heat or humidity Tropism – a growth movement of part of a plant in response to a directional stimulus Positive phototropism – shoots/leaves Positive Geotropism – roots Section 9. 2 – Nervous Control Nervous organisation The nervous system can be thought of as having two main divisions: . The central nervous system (CNS) – brain and spinal cord 2. The peripheral nervous system (PNS) – Made up of pairs of nerves that originate either from the brain or the spinal cord The peripheral nervous system This is divided into: †¢ Sensory neurons which carry impulses away from receptors to the CNS †¢ Motor neurons which carry nervous impulses from the CNS to effectors The spinal cord is a column of nervous tissue A reflex – involuntary response to a stimulus (you do stop to consider an alternative) The pathway of neurons involved in a reflex is called a reflex arc. Reflex arcs contain just 3 neurons: 1. A sensory neuron 2. An intermediate neuron 3. A motor neuron There are several stages of a reflex arc: 1. Stimulus 2. Receptor 3. Sensory neuron 4. Synapse 5. Coordinator (intermediate neuron) 6. Synapse 7. Motor neuron 8. Effecter 9. Response Importance of the reflex arc †¢ Involuntary – does not require the decision making power of the brains †¢ Brain can override the response if necessary †¢ Protects the body from harmful stimuli Effective from birth – does not need to be learnt †¢ Short pathway – fewer synapses Synapses – slow Neurons – fast Section 9. 3 – Control of heart rate The Autonomic nervous system Controls subconscious activities of muscles and glands Has two main divisions: The sympathetic nervous system – Speeds up activities and thus allows us to cope with stressful situations (fight or flight r esponse) The parasympathetic nervous system – Inhibits effects and slows down activities. This allows energy to be conserved. Controls under normal resting conditions The two divisions are antagonistic meaning that their effects oppose one another Control of heart rate Changes of the heart rate are controlled by a region of the brain called the medulla oblongata which has two main divisions One division is connected to the sinoatrial node through the sympathetic nervous system The other is connected to the sinoatrial node via the parasympathetic nervous system Control by chemoreceptors Chemoreceptors are found in the wall of the carotid arteries and detect hanges in pH as a result of CO2 concentration When CO2 concentration in the blood is too low, chemoreceptors detect the drop in pH and send impulses to the section of the medulla oblongata responsible for increasing heart rate This section then increases the number of impulses sent to the S. A node via the sympathetic nervous system This results in an increase in heart rate which then causes blood pH to return to normal. Control by pressure receptors Pressure receptors occur in the wall of the carotid arteries and the aorta When blood pressure is too high – impulses are sent to the medulla oblongata which then sends impulses to the S. A node via the parasympathetic nervous system decreasing the heart rate When blood pressure is too low – impulses are sent to the medulla oblongata which then sends impulses to the S. A node via the sympathetic nervous system, increasing the heart rate Section 9. 4 – Role of receptors Features of sensory reception A sensory receptor will: †¢ Only respond to a specific type of stimulus (e. g. light, pressure, etc) †¢ Produce a generator potential by acting as a transducer. This means that it can convert the information to a form that the human body can interpret. This is achieved by using the energy of a stimulus into a nerve impulse called a generator potential. Structure and function of a pacinian corpuscle Responds to mechanical pressure Occurs in ligaments and joints so that it is possible to tell which direction a joint is changing The neuron of a pacinian corpuscle is in the centre of layers of tissue, each separated by gel The sensory neuron of a pacinian corpuscle has stretch-mediated sodium channels in its plasma membrane †¢ During its resting state, stretch-mediated sodium channels are too narrow to allow sodium through. The corpuscle therefore has a resting potential †¢ When pressure is applied, the membrane of the neuron is stretched causing sodium channels to widen therefore allowing sodium to diffuse into the neuron †¢ The influx of sodium ions cause a change in the polarity of the neuron, creating a resting potential †¢ The generator potential creates a action potential which moves along the neuron Receptors working together in the eye Different receptors respond to a different intensity of a stimulus Light receptors of the eye are found in the retina (the inner most layer) The light receptors in the eye can are of two types, rod and cone cells. Both receptors convert light energy into a nervous impulse and are therefore acting as transducers Rod cells Cannot distinguish between different wavelengths Many rod cells are connected to the same neuron and so can function at low light intensities. A threshold must be reached in the bipolar cells to which they are attached to and so since they can all contribute to reaching this threshold, they will function at lower light intensities Rod cells breakdown the pigment rhodopsin to generate an action potential. Rhodopsin is easily broken down in low light intensity Since more that one rod cell is connected to the same neuron, only one impulse will be generated. It is impossible for the brain to determine which rod cells were stimulate to begin with and so it is not possible to determine exactly the source of light This results in rod cells having a relatively poor visual acuity and so are not very effective in distinguishing between two points close together Cone cells There are three types of cone cells, each of which respond to a different avelength The colour interpreted depends of the proportion of each type of cone cell stimulated Cone cells are connected only to one bipolar cells, this means that they cannot combine to reach a threshold. As a result of this a high light intensity is required to create a generator potential Cone cells breakdown the pigment iodopsin to create a generator potential Iodopsin can only be broken down by a high light intensity Since cone cells are connected to a single bipolar cell, when two adjacent cells are stimulated, two separate nervous impulses will be sent to the brain. This means that it is easier to determine the source of the light. As a result, cone cells are responsible for higher visual acuity since they allow you to better distinguish between two points Light is concentrated by a lens to the centre of the eye called the fovea. This region receives a high light intensity and therefore has more cone cells. The peripheries of the eye receive a low light intensity and therefore consist mainly of rod cells. Section 10. 1 – Coordination Body systems cannot work in isolation and must therefore be integrated in a coordinated fashion. Principles of coordination In mammals, there are two main forms of coordination: 1. The nervous system – Uses nerve cells that can pass electrical impulses along their length. The result is the secretion of chemicals by the target cells called neurotransmitters. The response is quick, yet short lived and only acts on a localised region of the body. 2. The hormonal system – Chemicals are transported in the blood plasma which then reach target certain cells, thus stimulating them to carry out a function. The responses due to secretion of hormones often act over a longer period of time, yet are slower to act. Chemical mediators Nervous and hormonal forms of communication are only useful at coordinating the activities of the whole organism. At the cellular level they are complimented by chemical mediators. Chemical mediators are secreted by individual cells and affect other cells in the immediate vicinity. A common example of this type of coordination is the inflammation of certain tissues when they are damaged or exposed to foreign agents. Two examples of chemical mediators are: 1. Histamine – Stored in white blood cells and is secreted due to the presence of antigens. Histamine causes dilation of blood vessels, increased permeability of capillaries and therefore swelling the infected area. 2. Prostaglandins – Found in cell membranes and cause dilation of small arteries and arterioles. They release due to injuries and increase the permeability of capillaries. They also affect blood pressure and neurotransmitters. In doing so they relieve pain. Hormonal system |Nervous system | |Communication by chemicals |Communication by nervous impulses | Transmission takes place in the blood |Transmission is by neurons | |Transmission is generally slow |Transmission is very rapid | |Hormones travel to all areas of the body, but target only |Nerve impulses travel to specific areas of the body | |certain tissues/organs | | |Response is widespread |Response is localised | |Effect may be permanent/long lasting/ irreversible |Effect is temporary and reversible | Plant growth factors Plants respond to external stimuli by means of plant growth factors (plant hormones) Plant growth factors: †¢ Exert their influence by affecting growth †¢ Are not produced by a particular organ, but are instead produced by all cells †¢ affect the tissues that actually produce them, rather than other tissues in a different area of the plant. One plant hormone called indoleacetic acid (IAA) causes plant cells to elongate Control of tropisms by IAA IAA is used to ensure that plant shoots grow towards a light source. 1. Cells in the tip of the shoot produce IAA, which is then transported down the shoot. 2. The IAA is initial transported to all sides as it begins to move down the shoot 3. Light causes the movement of IAA from the light side to the shaded side of the shoot. 4. A greater concentration of IAA builds up on the shaded side of the shoot 5. The cells on the shaded side elongate more due to the higher concentration of IAA 6. The shaded side of the root therefore grows faster, causing the shoot to bend towards the source of light IAA can also effect the bending of roots towards gravity. However in this case it slows down growth rather than speeds it up. IAA decreases root growth and increases shoot growth Section 10. 2 – Neurons Specialised cells adapted to rapidly carry electrochemical changes (nerve impulses) from part of the body to another Neuron structure Cell body †¢ Nucleus †¢ Large amounts of rough endoplasmic reticulum to produce neurotransmitters Dendrons †¢ Extensions of the cell body sub-divided into dendrites †¢ Carry nervous impulses to the cell body Axon †¢ A single long fibre that carries nerve impulses away from the cell body Schwann cell †¢ Surrounds the axon †¢ Protection/electrical insulation/phagocytosis. Can remove cell debris and are associated with nerve regeneration. Myelin sheath †¢ Made up from the Schwann membrane which produces myelin (a lipid) †¢ Some neurons are unmyelinated and carry slower nerve impulses Nodes of Ranvier †¢ The gaps between myelinated areas †¢ 2 – 3 micrometers long and occur every 1 – 3mm Sensory Neuron †¢ Transmit impulses from a receptor to an intermediate neuron or motor neuron †¢ One Dendron towards the cell body, one axon away from the cell body Motor neuron †¢ Transmit impulses from the sensory/intermediate neuron to an effector †¢ Long axon, many short dendrites Intermediate neuron †¢ Transmit impulses between neurons †¢ Numerous short processes Section 10. 3 – The nerve impulse A nerve impulse is not an electrical current! It is a self-propagating wave of electrical disturbance that travels along the surface of an axon membrane. Nerve impulse – temporary reversal of the electrical p. d across an axon membrane The reversal is between two states The resting potential no nerve impulse transmitted The action potential – nerve impulse transmitted Resting potential †¢ Sodium/potassium are not lipid soluble and cannot cross the plasma membrane. Transported via intrinsic proteins – ion channels †¢ Some intrinsic proteins actively transport potassium ions into the axon and sodium ions out. This is called the sodium potassium pump. Sodium potassium pump 3 sodium ions pumped out for every 2 potassium ions pump in †¢ Most gated potassium channels remain open – potassium ions move out of the axon down their chemical gradient †¢ Most gated sodium channels remain closed The action potential †¢ Temporary reversal of the charge of the membrane from (-65mV to +65mV). When the p. d is +65mV the axon is said to be depolarised †¢ Occurs because the ion channels open/close depending upon the voltage across the membrane †¢ When the generator potential is reached, sodium ion channels open and potassium close, allowing sodium to flood into the axon. Sodium being positively charged causes the axon to become more positive in charge The passage of an action potential along an unmyelinated axon †¢ Stimulus – some voltage – gated ion channels open, sodium ions move in down electrochemical gradient †¢ Causes more sodium channels to open †¢ When the action potential reaches ~ +40mV sodium channels close †¢ Voltage – gated potassium channels open and begin repolarisation of the axon Hyper – polarisation †¢ The inside of the axon becomes more negative than usual due to an â€Å"overshoot† in potassium ions moving out of the axon. †¢ Potassium channels close †¢ Sodium potassium pump re-established the -65mV resting potential Section 10. 5 – The speed of a nerve impulse Factors affecting speed 1. The myelin sheath – Prevents the action potential forming in myelinated areas of the axon. The action potential jumps from one node of Ranvier to another (salutatory conduction) – this increases the speed of the impulse as less action potentials need to occur 2. The greater the diameter of the axon the greater the speed of conductance – due to less leakage of ions from the axon 3. Temperature – Higher temperature, faster nerve impulse. Energy for active transport comes from respiration. Respiration like the sodium potassium pump is controlled by enzymes. Refractory period After an action potential, sodium voltage-gated channels are closed and sodium cannot move into the axon. It is therefore impossible during this time for a further action potential to be generated. This time period, called the refractory period serves two purposes: It ensures that an action potential can only be propagated in one direction – An action potential can only move from an active region to a resting region. It produces discrete impulses – A new action potential cannot be generated directly after the first. It ensures action potentials are separated from one another. It limits the number of action potentials – action potentials are separated from one another, therefore there is a limited amount that can pass along a neuron in a given time. All or nothing principle Nervous impulses are all or nothing responses A stimulus must exceed a certain threshold value to trigger an action potential A stimulus that exceeds the threshold value by a significant amount, will produce the same strength of action potential as if it has only just overcome the threshold value A stimulus can therefore only produce one action potential An organism can perceive different types of stimulus in two ways: The number of impulses in a given time (larger stimulus, more impulses per second) Having neurons with different threshold values – depending on which neurons are sending impulses, and how frequently impulses are sent, the brain can interpret the strength of the stimulus Section 10. 6/10. 7 – Structure and function of the synapse / Transmission across a synapse A synapse occurs where a dendrite of one neuron connects to the axon of another Structure of a synapse Synapses use neurotransmitters to send impulses between neurons The gap between two neurons is called the synaptic cleft The neuron that produces neurotransmitters is called the presynaptic neuron The axon of the presynaptic neuron ends in a presynaptic knob The presynaptic knob consists of many mitochondria and endoplasmic reticulum These organelles are required to produce neurotransmitters which are stored in synaptic vesicles Synaptic vesicles can fuse with the presynaptic membrane releases the neurotransmitter Functions of synapses †¢ A single impulse from neuron can be transmitted to several other neurons at a synapse. This means that one impulse can create a number of simultaneous responses †¢ A number of different impulses can be combined at a synapse. This means that several responses can be combined to give on single response Neurotransmitters are made in the presynaptic cleft only When an action potential reaches the presynaptic knob, it causes vesicles containing the neurotransmitter to fuse with the presynaptic membrane The neurotransmitter will the diffuse across the synaptic cleft The neurotransmitter then bind with receptors on the postsynaptic membrane, in doing so generating a new action potential in the postsynaptic neuron Features of synapses Unidirectionality Impulses can only be sent from the presynaptic membrane to the postsynaptic membrane Summation †¢ Spatial summation Different presynaptic neurons together will release enough neurotransmitter to exceed the threshold value to form an action potential †¢ Temporal summation – One neuron releasing neurotransmitter many times over a short period. Eventually the neurotransmitter will accumulate so as to overcome the threshold value of the postsynaptic membrane. Therefore generating a new action potential Inhibition Some postsynaptic membranes have protein channels that can allow chloride ions to diffuse into the axon making it more negative than usual at resting potential. This type of hyperpolarisation inhibits the postsynaptic neuron from generating a new action potential. The importance of these inhibitory synapses is that it allows for nervous impulses to be controlled and stopped if necessary Transmission across a synapse When the neurotransmitter across a synapse is the chemical acetylcholine it is called a cholinergic synapse Acetylcholine is made up of acetyl (ethanoic acid) and choline Cholinergic synapses are more common in vertebrates Cholinergic synapses occur in the central nervous system and at neuromuscular junctions 1. When an action potential reaches the presynaptic knob, calcium channels open allow calcium to diffuse into the presynaptic knob 2. The influx of calcium ions causes presynaptic vesciles containing acetylcholine to fuse with the presynaptic membrane, releasing the neurotransmitter into the synaptic cleft 3. Acetylcholine diffuses across the cleft and fuses with receptor sites on sodium channels found on the presynaptic membrane. When they do so, the sodium channels open, allowing sodium ions to diffuse along their concentration gradient into the postsynaptic knob. 4. The influx of sodium ions, generates a new action potential in the postsynaptic neuron 5. Acetylcholinesterase hydrolyses acetylcholine back into the acetyl and choline which will the diffuse back across the synaptic cleft into the presynaptic neuron. In this way acetylcholine can be recycles and reused and also is prevented from continuously generating new action potentials on the postsynaptic neuron. 6. ATP is released by mitochondria, providing energy to recombine acetyl and choline. Sodium channels on the postsynaptic membrane are now closed due to the absence of acetylcholine attached to receptor sites. Section 11. 1 – Structure of skeletal muscle There are three types of muscle in the body: Cardiac muscle which is found only in the heart Smooth muscle which is found in the walls of blood vessels Skeletal muscle which is attached to bone and is the only type of muscle under conscious control Muscles are made up of many muscle fibres called myofibrils If the cells of muscles were joined together from the end of one cell to another, the point between cells would be a point of weakness Because of this, the muscle cells are fused together into muscle fibres Cells of the same myofibrils share the same nuclei as well as cytoplasm (sarcosplasm). Within the sacroplasm are many mitochondria as well as endoplasmic reticulum Microscopic structure of skeletal muscle Myofibrils are made up of two types of protein filament Actin – thinner, consists of two strands twisted around each other Myosin – thicker and is made up of long rod shaped fibres with bulbous heads projecting outwards Myofibrils have coloured bands The isotropic (I) bands appears lighter since it consists only of actin (no overlap) The anisotropic (A) bands are darker since this is where acting and myosin overlap The H zone is the region in the centre of the sarcomere that is lighter in colour since there is only myosin The z line lies at the centre of the I bands Types of muscle fibre Slow-twitch fibres – Contract more slowly, less powerful. Adapted for endurance/aerobic respiration so less lactic acid forms Adaptations include: Large store of myoglobin, Supply of glycogen, Rich supply of blood vessels, Numerous mitochondria Fast-twitch – Contracts more rapidly with more power but only for a short period of time. Adapted for intense exercise by: Having hicker and more numerous myosin filaments, having a high concentration of enzymes used for anaerobic respiration, a large store of phosphocreatine to provide phosphate to make ATP Neuromuscular junctions Many neuromuscular junctions are spread through the muscle for simultaneous contraction Each muscle fibre has one motor neuron associated with it. The muscle fibre and the neuron make up one motor unit When only a small force is needed only a few motor units are stimulated When a nerve impulse reaches the neuromuscular junction, the synaptic vesicles join with the presynaptic membrane and release acetylcholine which diffuses across to the postsynaptic membrane and stimulates it to allow sodium ions to enter. The acetylcholine is then broken down by Acetylcholinesterase and then diffuses back into the presynaptic neuron. Section 11. 2 contraction of skeletal muscle During muscle contract, actin and myosin slide past each other; hence its name the sliding filament mechanism Evidence for the sliding filament mechanism When a muscle contract, the following changes occur to the sarcomere: The I band becomes narrower The z lines move close to one another The h band becomes narrower The a band does not change as this band is determined by the width of the myosin Myosin is made up of two different types of protein 1. A fibrous protein arranged into the filament called the tail 2. A globular protein that forms a head at each end Actin is a globular proteins thats molecules are arranged into two chains that twist around each other in a helical manner Tropomyosin forms long thin stands that s wound around the actin molecule The process of muscle contraction has a three main stages: Stimulation, contraction and relaxation Muscle stimulation When an action potential reaches the neuromuscular junctions, Calcium ion channels open and calcium ions move into the synaptic knob The Calcium ions cause the synaptic vesicles to move to the presynaptic membrane and fuse with it releasing acetylcholine Acetylcholine diffuses across the synaptic cleft and binds with receptors on the sodium voltage gated channels on the postsynaptic membrane causing it to depolarise Muscle contraction The action potential movies through the fibres by travelling through T – tubules that branch through the sarcoplasm The action potential moves through the tubules until it reach the sarcoplasmic reticulum The action potential opens calcium ions in the sarcoplasmic reticulum Calcium ions diffuse out into the muscle Calcium ions cause tropomyosin to change shape and so that the binding sites on the actin filament are exposed An ADP molecule that is attached to the myosin heads allows it to form a cross bridge with actin by binding with the receptor site Once the cross bridge is formed, the myosin head changes shape and slides the actin across. In doing so it loses the ADP An ATP molecule attaches to the myosin head and thus causes it to detach Calcium ions activate the enzyme ATPase which hydrolyses ATP and releases energy that allows the myosin head to resume its original shape. The myosin head now has a new ADP molecule that will allow it to bind with a new receptor site somewhere along the actin filament Muscle relaxation When the muscle is not being stimulated, the sarcoplasmic reticulum actively transport calcium ions back into it The lack of calcium ions means that tropomyosin can establish its original position, covering the myosin head binding sites Energy supply Energy is needed for the movement of myosin heads and the active transport of calcium ions ATP often needs to be generated anaerobically Phosphocreatine provides inorganic phosphate molecules to combine with ADP to form ATP Section 12. 1 – Principle of homeostasis The maintenance of a constant internal environment By maintaining a relatively constant environment (of the tissue fluid) for their cells, organisms can limit the external changed these cells experience thereby giving the organisms a degree of independence. What is homeostasis? Maintaining the volume, chemical make up and other factors of blood and tissue fluid within restricted limits There are continuous fluctuations; however, they occur around a set point Homeostasis is the ability to return to that set point thus maintaining equilibrium The importance of homeostasis Enzymes and other proteins are sensitive to changes in pH and temperature Water potential of blood and tissue fluid should be kept constant to ensure cells do not burst or shrink due to a net movement of water (osmosis) Maintaining a constant blood glucose concentration ensures that the water potential of the blood remains the same Independence of the external environment – a wider geographical range and therefore a greater chance of finding food shelter, etc Mammals – homeostasis allows them to tolerate a wide range of conditions Control mechanisms The set point is monitored by: 1. Receptor 2. Controller brain analyses and records information from a number of different sources and decides on the best course of action 3. Effector – brings about the change to return to set point 4. Feedback loop – informing the receptor of the changes in the system brought about by the effector Section 12. 2 Thermoregulation Mechanisms of heat loss and gain Production of heat – Metabolism of food during respiration Gain of heat from the environment – Conduction, convection (surrounding air/fluid), Radiation (electromagnetic waves particularly infrared) Mechanisms for losing heat Evaporation of water Conduction – to ground/solid Convection convection (to surrounding air/fluid), Radiation Endotherms derive most heat energy from metabolic activities Ectotherms – obtain most heat from the external environment Regulation of body temperature in Ectotherms Body temp fluctuates with the environment Controlled by exposure to the sun Shelter to the sun/burrows at night/obtains heat from the ground and very little from respiration. Can sometimes change colour to alter heat that is radiated Regulation of body temperature in Endotherms Most heat gained through internal metabolic activities Temperature range 35 – 44 oC – Compromise between higher temperature where enzymes work more rapidly and the amount of energy needed (hence food) to maintain that temperature Conserving and gaining heat in response to a cold environment Long term adaptations: Small SA:V ration Therefore mammals and birds in cold environments are relatively large Smaller extremities (e. g. ears) thick fur, feathers or fat reserves to insulate the body Rapid changes: Vasoconstriction – reducing the diameter of arteries/arterioles Shivering – in voluntary rapid movements and contractions that produce he energy from respiration Raising hair – enables a thick layer of still air to build up which acts as a good insulator. Behavioural mechanisms – bathing in the sun Decreased sweating Loss of heat in response to a warm environment Long term adaptations: Large SA:V ratio so smaller animals are found in warmer climates Larger extremities Light coloured fur to reflect heat Vasodilation – Arterioles increase in diameter, more blood reaches capillaries, more heat is therefore radiated away Increased sweating – Heat energy is required to evaporate sweat (water). Energy for this comes from the body. Therefore, removes heat energy to evaporate water Lower body hair – Hair erector muscles relax. Hairs flatten, reduces the insulating layer of air, so more heat can be lost to the environment Behavioural mechanisms – seeking shade, burrows, etc Control of body temperature Mechanisms to control body temperature are coordinated by the hypothalamus in the brain The hypothalamus has a thermoregulatory centre divided into two parts: A heat gain centre which is activated by a fall in body temperature And a heat loss centre which is activated by an increase in temperature The hypothalamus measures the temperature of blood passing through it Thermoreceptors in the skin also measure the temperature Impulses sent to the hypothalamus are sent via the autonomic nervous system The core temperature in the blood is more important that the temperature stimulating skin Thermoreceptors Section 12. 3/12/4 – Hormones and the regulations of blood glucose/Diabetes and its control Hormones are produced by glands (endocrine glands) which secrete the hormones into the blood The hormones are carried in the blood plasma to the target cells to which they act. The target cells have complementary receptors on the cell surface membrane Hormones are affective in small quantities set have widespread and long-lasting affects Some hormones work via the secondary messenger model: 1. The hormone (the first messenger) binds to receptors on the cell surface membrane, forming a hormone-receptor complex 2. The hormone-receptor complex activates an enzyme inside the cell that produces a secondary messenger chemical 3. The secondary messenger acts within the cell produces and a series of changes Both glucagon and adrenaline work by the secondary messenger model Adrenaline as a secondary messenger 1. The hormone adrenaline forms a hormone-receptor complex and therefore activates an enzyme inside the cell membrane 2. The activated enzyme the converts ATP to cyclic AMP which acts as the secondary messenger.