Wednesday, May 20, 2020
End of Chapter Solutions Corporate Finance 8th edition Ross, Westerfield, and Jaffe Updated 11-21-2006 CHAPTER 1 INTRODUCTION TO CORPORATE FINANCE Answers to Concept Questions 1. In the corporate form of ownership, the shareholders are the owners of the firm. The shareholders elect the directors of the corporation, who in turn appoint the firmÃ¢â¬â¢s management. This separation of ownership from control in the corporate form of organization is what causes agency problems to exist. Management may act in its own or someone elseÃ¢â¬â¢s best interests, rather than those of the shareholders. If such events occur, they may contradict the goal of maximizing the share price of the equity of the firm. Such organizations frequently pursue social orÃ¢â¬ ¦show more contentÃ¢â¬ ¦How much is too much? Who is worth more, Jack Welch or Tiger Woods? The simplest answer is that there is a market for executives just as there is for all types of labor. Executive compensation is the price that clears the market. The same is true for athletes and performers. Having said that, one aspect of executive compensation deserves comment. A primary rea son executive compensation has grown so dramatically is that companies have increasingly moved to stock-based compensation. Such movement is obviously consistent with the attempt to better align stockholder and management interests. In recent years, stock prices have soared, so management has cleaned up. It is sometimes argued that much of this reward is simply due to rising stock prices in general, not managerial performance. Perhaps in the future, executive compensation will be designed to reward only differential performance, i.e., stock price increases in excess of general market increases. 8. 9. 10. Maximizing the current share price is the same as maximizing the future share price at any future period. The value of a share of stock depends on all of the future cash flows of company. Another way to look at this is that, barring large cash payments to shareholders, the expected price of the stock must be higher in the future thanShow MoreRelatedCorporate Finance Notes1881 Words Ã |Ã 8 PagesStudy notes By Zhipeng Yan Corporate Finance Stephen A. Ross, Randolph W. Westerfield, Jeffrey Jaffe Chapter 1 Introduction to Corporate Finance ..................................................................... 2 Chapter 2 Accounting Statements and Cash Flow.............................................................. 3 Chapter 3 Financial Markets and NPV: First Principles of Finance................................... 6 Chapter 4 Net Present Value....................................Read MoreNotes for Corporate Finance2082 Words Ã |Ã 9 PagesCorporate Finance Notes * Chapter One: Introduce to Corporate Finance 1. Three Questions: A. What Long-term asset should be invested? Capital Budgeting B. How to raise cash for capital expenditures? Capital Structure C. How to manage short-term cash flow? Net Working Capital 2. Capital Structure: Marketing Value of Firm = MV of Debt + MV of Equity 3. Finance perspect and Accountant perspect: Finance: Cash Flow ! Accountant: A/R means profit ! 4. Sole proprietorshipRead MoreCorporate Finance69408 Words Ã |Ã 278 PagesCorporate finance P. Frantz, R. Payne, J. Favilukis FN3092, 2790092 2011 Undergraduate study in Economics, Management, Finance and the Social Sciences This subject guide is for a Level 3 course (also known as a Ã¢â¬Ë300 courseÃ¢â¬â¢) offered as part of the University of London International Programmes in Economics, Management, Finance and the Social Sciences. This is equivalent to Level 6 within the Framework for Higher Education Qualifications in England, Wales and Northern Ireland (FHEQ). For moreRead MoreCorporate Finance4881 Words Ã |Ã 20 PagesTrends of Leverage 7 2.3 Comparison of capital structure with similar companies 9 2.4 Capital expenditures and its financing 10 2.5 Important factors influencing the use of debt financing 10 2.5.1 Tax Advantage 10 2.5.2 Corporate Tax Rate 11 2.5.3 Credit rating 11 2.5.4 Interest rate 11 2.5.5 CompanyÃ¢â¬â¢s Industry 12 2.5.6 CompanyÃ¢â¬â¢s growth rate 12 2.5.7 Some other arguments about Harvey Norman 12 2.6 Evidence of financial distress 13 Read MoreCorporate Finance1421 Words Ã |Ã 6 Pagesoperating earnings of the firm. The capitalization is to be made at a rate appropriate to the risk class of the firm. Growth Plans, are involved in capital structural theories in which a certain amount will be allocated for the growth plans. A finance manager should draw a plan according for the dividend policy. For Example: The firm has $10 million as equity capital and $6 million as debt capital and the firm made a profit (after tax) of $2 million, and the fund allocated to the growth plan wasRead MoreCorporate Finance - Concept Questions12247 Words Ã |Ã 49 Pagesquestions of corporate finance? a. Investment decision (capital budgeting): What long-term investment strategy should a firm adopt? b. Financing decision (capital structure): How much cash must be raised for the required investments? c. Short-term finance decision (working capital): How much short-term cash flow does company need to pay its bills. ( Describe capital structure. Capital structure is the mix of different securities used to finance a firms investmentsRead MoreFundamentals of Corporate Finance 9e82683 Words Ã |Ã 331 Pageshttp://helpyoustudy.info Chapter 01 - Introduction to Corporate Finance Chapter 01 Introduction to Corporate Finance Answer Key Multiple Choice Questions 1. Which one of the following terms is defined as the management of a firm s long-term investments? A. working capital management B. financial allocation C. agency cost analysis D. capital budgeting E. capital structure Refer to section 1.1 AACSB: N/A Difficulty: Basic Learning Objective: 1-1 Section: 1.1 Topic: Capital budgeting Read MoreCorporate Business Finance 7343 Words Ã |Ã 30 PagesCorporate Business Finance Seminar 5 Project Finance Lauren Leigh Essaram 207507339 Ruvimbo Mukorera 206525531 27 September 2010 Submitted in partial fulfilment of the duly performed requirement of International Business Finance, School of Economics and Finance, University of KwaZulu-Natal Abstract Non-recourse financing has grown in popularity, especially in developing countries. It has done so more specifically in the basic infrastructure, natural resources and also in the energyRead MoreAdvanced Corporate Finance4303 Words Ã |Ã 18 PagesUniversity of Puget Sound School of Business and Leadership BUS 434 Advanced Corporate Finance Professor Alva Wright Butcher Tues-Thurs 11:00-12:20 McIntyre 107 Spring Semester 2012 Office: McIntyre 111 I Phone: 253-879-3349 FAX: 253-879-3156 Office Hours: T-Th: 1:00-1:50 Wed: 9:30-10:30 And by appointment Note that I am always willing to schedule additional office hours by appointment. I check email frequently, so that is also a goodRead MoreEssay Corporate Finance1613 Words Ã |Ã 7 Pages Why is corporate finance important to all managers? Corporate finance is a specific area of finance dealing with the financial decisions corporations make and the tools as well as analyses used to make these decisions. The primary goal of corporate finance is to enhance corporate value, without taking excessive financial risks. A corporations managements primary responsibility is to maximize the shareholders wealth which translates to stock price maximization. Corporate finance provides
Tuesday, May 19, 2020
Page 1. I think that society should permit the use of drugs for recreational purposes. After all, over twenty years of troop sweeps, police actions and military rhetoric, the evidence is all around us. The war on drugs has flopped. It has been more then ineffective and has actually made things worse. We as American citizens have to wake up and realize that there will never be a Ã¢â¬Å"drug freeÃ¢â¬ utopia that we have been promised. People will always be willing to experiment with their bodies and use drugs no-matter the cost involved in doing so. It is our human nature to want things we canÃ¢â¬â¢t have and to crave addictive substances whether it is heroin or that addictive chocolate bar in the express lane aisle of yourÃ¢â¬ ¦show more contentÃ¢â¬ ¦is literally endless. We have to remember that whether someone wants to do drugs is there personal choice and in the end; thereÃ¢â¬â¢s alone. In this situation we need to take action by allowing our pharmaceutical companies the ability to produce safer drugs with the same effects as those on the streets, this intern would allow American companies to profit here and around the world, drug dealers to loose their clout and to take the immediate burden of the tax payers of this country. The immediate effect of a legalized drug market would be increased safety for drug users. All clean and natural drugs such as marijuana, cocaine and heroin are pathologically harmless if taken in appropriate doses and not tampered with in a lab before hand. A regulated drug market would do just this and provide such safety for drug users as consistent doses, lowering the likelihood of overdoses with some drugs. Clear labeling, instructions, and warnings like those listed by the surgeon general on a pack of cigarettes would result in safer usage. The legalization of drugs would allow pharmaceutical companies to profit by allowing them to research and eventually create safer drugs that produce similar side effects to the Page 4. current illegal ones. At the same time there would be significant tax revenues that would be included into the big picture. Overall these new
Wednesday, May 6, 2020
During the 20th century there were numerous riots, protests, and boycotts fighting for the equality and social integration of African-Americans. Some of the stories of individuals endeavoring for their freedom have gone down in historyÃ¢â¬âresulting in laws being altered, regulations being revised, and unimaginable boundaries being broken. Sadly, in order to establish justice in this world, violence and death usually occur due to conflicting ideals. In Southern Los Angeles, even after African-Americans were issued their Ã¢â¬Å"Civil Rights,Ã¢â¬ underlying racism constructed barriers such as Ã¢â¬Å"racial restrictive covenantsÃ¢â¬ that ensured that blacks were still not welcome there. The two biggest social disturbances that have taken place in the West have taken place in Los AngelesÃ¢â¬âwhere unemployment, overcrowding, poverty, and segregation have become increasingly prevalent. The first of these social disturbances is the Rodney King riot of 1992 and the second is the Watts riot of 1965. The racial bigotry, which was backed by the racial restrictive covenants and racial discrimination of LAPD throughout Southern Los Angeles; as well as the events that sparked the Rodney King riot and the Watts riot; clearly illustrate the racial segregation and the overall struggle that African-Americans faced during the 20th century. Between 1910 and 1920 in what is commonly known as the Great Migration among 300,000 and 1,000,000 African-Americans made their way toward northern cities to try and escape theShow MoreRelatedEssay on Nonviolence or Violence: Which Was More Effective?1425 Words Ã |Ã 6 PagesThe Civil Rights Movement brought many accomplishments to African Americans such as the 1964 Civil Rights Act, Voting Rights Act of 1965, and the Fair Housing Act of 1968. The key issues that African Americans fought for were voting rights, integration and racial equality. They were tired of the discrimination and humiliation they received as a result of the segregation laws imposed on them. Ã¢â¬Å"State laws mandated racial separation in schools, parks, playgrounds, restaurants, hotels, public transportationRead More The Little Rock Nine Essay1548 Words Ã |Ã 7 Pagesnine African American students were chosen to desegregate Central High in Little Rock. How did the Little Rock Nine affect America? Sanford Wexler stated in The Civil Rights Movement: An Eyewitness History,Ã¢â¬ its Ã¢â¬Å"effect would ripple across the nation and influence the growing Civil Rights Movement;Ã¢â¬ in addition, the Little Rock crisis forced the federal government to come down on state government in order to protect the rights of African Americans. In September 1957, nine African American highRead MoreI Have A Dream Speech1508 Words Ã |Ã 7 PagesThis gained the support of thousands African-American people and not only from the ones who participated in the event. It also gained support of prominent colored members of the community. Martin Luther King Junior, a Baptist minister in Montgomery, emerged as a prominent figure for this movement. King helped to found the Southern Christian Leadership Conference, a civil rights organization that founght to end racial segregation in the south (History-Civil Rights Movement). In August of nineteen-sixty-threeRead MoreAfrican Americans During World War I1579 Words Ã |Ã 7 PagesMany African Americans had moved north during the Great Migration to escape conditions in the south, but found that discrimination was still prevalent in northern cities. African Americans not only had difficulties finding jobs, but still felt the stigma of being black. Living within the time of legal discrimi nation, many African Americans soon realized that though they may have escaped the violence of the south, they still had to deal with the challenges and setbacks of being black in America. TheRead MoreMastering The Art Of Subtle Racism1732 Words Ã |Ã 7 Pagesprofound history in regards to racism and civil rights. As racial relations grew and evolved, the south became notorious for lagging behind the progressive movements seemingly led by the north. The south is wrought with historical locations pivotal to the Civil Rights struggle therefore the south is highlighted and portrayed as the impeding figure to racial equality. Contrary to popular belief, the north was not a progressive leader during the civil rights movement, but instead northern racism residedRead MoreEssay about The Battle of Ole Miss1600 Words Ã |Ã 7 PagesBATTLE OF OLE MISS AS IT RELATES TO THE AFRICAN-AMERICAN EXPERIENCE AND AMERICAN HISTORY A TERM PAPER SUBMITTED TO PROFESSOR K.R.V. HENINGBURG DEPARTMENT OF HISTORY BY MONA SALIMI SACRAMENTO, CA 19 APRIL 2010 James MeredithÃ¢â¬â¢s successful campaign to gain admission to the Univeristy of Mississippi, Ã¢â¬ËOle MissÃ¢â¬â¢, and desegregate education in the state most resistant to integration of educational institutions, has become a crucial episode in civil rights history. Ole Miss transformed MississippiRead MoreEssay on Martin Luther Kings Successful Philosophy1019 Words Ã |Ã 5 Pagescountry that had practiced slavery. African Americans didnÃ¢â¬â¢t gain their freedom until after the Civil War, nearly one-hundred years later. Even though African Americans were freed and the constitution was amended to guarantee racial equality, they were still not treated the same as whites and were thought of as second class citizens. One man had the right idea on how to change America, Martin Luther King Jr. had the best philosophy for advancing civil rights, he preached nonviolence to expressRead MoreThe Achievement And Progression Of African Americans1454 Words Ã |Ã 6 Pageswomen, im migrants, and indigenous people an equal and equitable access to the civil rights and liberties bestowed upon other citizens of this country. This sentiment rings especially true, as it relates to education, as these groups have all been disadvantaged and disenfranchised at different points in American history. The disservice that the United States has constructed against the success and progression of African-Americans, should be more duly noted, as they are the diversity group the most in needRead MoreGil Scott Heron Essay1407 Words Ã |Ã 6 Pagesforty years ago, however, rap music focused on an entirely different subject matter. During the 1970s, African Americans sung rap songs to express the need for Black empowerment in society; though their form of singing was not called rapping back then, it was called spoken word poetry, a form of song in which verses of poetry were performed with a fixed beat before an audience. African Americans used this style of singing to express the discontent with the economics and politics during the 1970s.Read MoreSegregation vs. Integration1387 Words Ã |Ã 6 PagesSegregation vs. Integration One of the most significant issues which the United States has dealt with for decades is the issue of racial segregation. In a post-Civil Rights era, there is a common tendency to assume that racism is no longer a pressing social concern in America due to the gradual erosion of whiteness. During the late 1800s and much of the 1900s, segregation had been a controversial and divisive issue throughout the country. This issue stemmed from the separation of African Americans and whites
Published on March 8, 1775, On African Slavery by Thomas Paine was available for the public ten months and two days before Common Sense. Despite the difference in publishing dates these two written works provide numerous similarities. For example, On African Slavery is addressed Ã¢â¬Å"To Americans:Ã¢â¬ (Paine 1) and Common Sense is similarly Ã¢â¬Å"Addressed to the Inhabitants of AmericaÃ¢â¬ (1). Furthermore, both written works address PaineÃ¢â¬â¢s belief that all men are Ã¢â¬Å"originally equalsÃ¢â¬ (71). In Common Sense, Paine uses this belief to discuss hereditary succession and monarchy, while in On African Slavery Paine uses this belief as a foundation of his argument against slavery. Hereditary succession is also discussed in On African Slavery, when addressingÃ¢â¬ ¦show more contentÃ¢â¬ ¦Make specific references using direct quotations. The use of the word Ã¢â¬Å"commonÃ¢â¬ may be found throughout the two works by Paine as well as the Declaration. For example, the Declaration of Independence uses Ã¢â¬Å"commonÃ¢â¬ when referring to Ã¢â¬Å"common kindredÃ¢â¬ (Jefferson 4) and Common Sense uses Ã¢â¬Å"commonÃ¢â¬ throughout the book when discussing a Ã¢â¬Å"common causeÃ¢â¬ (Paine 66), Ã¢â¬Å"common period of lifeÃ¢â¬ (66), and Ã¢â¬Å"common interestÃ¢â¬ (67). Furthermore, Ã¢â¬Å"commonÃ¢â¬ may be found in On African Slavery when discussing a Ã¢â¬Å"common LordÃ¢â¬ (1) and Ã¢â¬Å"common Justice and HumanityÃ¢â¬ (1). Another example of similar phrasing throughout PaineÃ¢â¬â¢s two works (Common Sense and On African Slavery) and the Declaration are found when condemning a King. Common Sense condemns the King multiple times, one example being Ã¢â¬Å"That the King is not to be trusted without being looked after,Ã¢â¬ (Paine 69). Similarly, the Declaration also condemns the King by explaining Ã¢â¬Å"The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in dire ct object the establishment of an absolute Tyranny over these States.Ã¢â¬ (Jefferson 2). Furthermore, On African Slavery explains Ã¢â¬Å"...that these inoffensive people are brought into slavery, by stealing them, tempting Kings to sell subjects, which they have no right to doÃ¢â¬ ¦Ã¢â¬ (Paine 1). Finally, all three documents similarly reference equality. The Declaration of Independence
Anesthetics Essay Anesthesia is a partial or complete loss of sensation or feeling induced by theadministration of various substances. For many decade, people have used one formof an anesthetic during surgical procedures. Some people also use some of theseanesthetics as recreational drugs, e.g. laughing gas (a.k.a. Nitrous Oxide). Theterm anesthetic literally means without feeling. There are manydifferent types of anesthesia, but they are usually put into three groups. Thesegroups are gene- ral anesthetics, local anesthetics, and spinal anesthetics. Ageneral anesthetic causes a complete loss of consciousness. They are used whenhaving a serious operation or in the case of an emergency operation. It works tothe surgeons advantage because the anesthesia reacts with the body in a matterof seconds. There are two different ways in which general anesthetics areadministered, they are intravenous and inhalation. The most popular procedure isintravenous. This is where the anesthetic is put into the body by way of aneedle in the vein, which is usually located in the hand or elbow. Althoughintravenous is more popular, it is usually used by itself during shortprocedures. In the case of longer procedures, intravenous anesthesia is alsoaccompanied by inhalation anesthesia. Inhalation anesthesia is administered byway of a mask and in the form of gas. Usually during long procedures, the maskwill remain on while the fluids from the intravenous anesthesia work throughyour body. The second group of anesthesia is local anesthesia. Local anesthesiais used when a doctor wants to numb a certain part of the body while youmaintain total consciousness. Local anesthetics are usually administered througha gel or cream on the surface of the skin, but can also be injected underneaththe skin, e.g. lidocane. If the anesthetic is placed on the surface of the skinthan the numbing effect should take place within a few seconds. If injectedunderneath the skin, it can take up to a few minutes to take effect. Both for msof local anesthesia are used when dealing with minor surgery such as dentistry,etc. The third and last group of anesthetics is the topical group. This group isassociated with childbirth, gynecological procedures, and spinal operations. Aspinal injection gives relief to pain, but at the same time allows for totalconsciousness. Usually the syringe is injected into the epidural layer of thespine. The effects of the spinal injection can be felt within minutes of theinjection. As I have already discussed, there are three different methods ofdistribution among anesthetics, inhalant, intravenous, and infusion. An inhalantis an anesthetic in the form of a gas which is administered by way of a gasmask. Intravenous anesthesia is administered by way of a needle into the vein. Infusion anesthetics are administered by way of a catheter. These three methodsoperate in four steps. The first of these steps is premedication or inductionstage. This step involves the nurse or practitioner to administer a form of asedative or muscle relaxant. This step is not always required, only when havingmajor surgery. The second stage is when the actual anesthesia is administered. The patient falls into a deep, pleasant state of unconsciousness. The thirdstage is when the drug is in full effect. The patient now experiences a loss ofconsciousness, although the patients reflexes still remain active and breathingis a little irregular. In the last stage, the fourth stage, the patient istotally unconscious. Muscels are fully relaxed and breathing becomes regular andquiet. Anesthesia has a long history which started in the middle 1700s. In1769, an English chemist, Joseph Priestley discovered the first recognizedanesthetic, nitrous oxide. Nitrous oxide is more commonly known as laughing gas. Although the gas was discovered in 1769, it wasnt until 1844 when an Americandentist by the name of Horace Wells, first put the nitrous oxide to use during adentistry procedure. The wonderful world of anesthesia was growing and becomingmore and more popular throughout the United States as well as in England. Thenext important discovery took place in 1829. In 1829, an American, MichealFaraday reported that the inhalation of ether caused a person to go into a stateof unconsciousness. Using ether as an anesthetic was not very popular, though. It was first used in 1842 when, an American doctor, Crawford W. Long removed atumor off of the neck of one of his patients. The second recorded use of etherwas by the American dentist, Thomas Green Morton in 1846. Morton along with thehelp of Charles Thomas Jackson, an American chemist, devel- oped a technique forpainless tooth extraction with the assistance of diethyl ether. In 1831, anAmerican physician and chemist, Samuel Guthrie was the first to discoverchloroform and its uses. The first to use chloroform during a surgical procedurewas Sir James Y. Simpson. Simpson was a Scottish obstetrician whom was notsatisfied with the action and reaction of ether. Simpson was the first to adoptchloroform as a useful anesthetic in surgical procedures. In 1884, Sigmund Freudwas the first to report cocaines anesthetic properties. An Austrailianphysician, Karl Koller, took this report of cocaine as an anesthetic and appliedit to surgical procedures. Kollers surgical procedure was even more impor tantbecause it was the first procedure to take place while using what we now calllocal anesthesia. Cocaine was the first local anesthesia to bediscovered and used in a surgical procedure. William Stewart Halsted, a profesorof surgery at John Hopkins University in Baltimore, was the first to use cocaineto anesthetize whole areas of the body by directly injecting the cocaine intothe nerve. In 1898, Karl Gustav Bier injected cocaine into vertebral canal andobtained paralysis of the lower extremities of the body. He used this method insurgical procedures. Since then this procedure that he discovered is know asspinal anesthesia and is widely used today. At around 1901, J.L. Corning usedcocaine to produce a useful spinal anesthetic, which in turn produced twoimportant cocaine derivatives, novocaine and procaine. Many other importantanalgesics and their uses came about between 1800 to 1900. Ethyl chloride whichwas introduced to us in 1848, was too short lived. Surgeons needed an anesth-eti c that was non-toxic and non-inflammable. So in 1929, cyclopropane wasintroduced to the medical world, but soon enough the medical world found outthat the drug was inflammable. In 1934, trichloreth- ylene was first used. Thisdrug on the other hand came along with two advantages. It reduced the awarenessof pain while maintaining full consciousness, which made the drug ideal forchildbirth use. In 1874, Ore of Bordeaux, was the first to achieve anintravenous anesthesia. He used Chloral to achieve this intravenous anesthesia. Examining The Project Of The Channel Tunnel Construction EssayXenon exhibits all the analgesic properties to eventually become an importantanesthetic in the medical world. Many advances have also been made tointravenous anesthetics as well. One of the newest types of intravenousanethesia is propofol. It is the newest intravenous drug to date. It wasintroduced to the medical world in 1984. Since then there have been incredibleadvances made in the administration, distribution, and maintenance of the drug,propofol. The drug has very few side effects, which include a mere nausea anddrowsiness. It has a very fast recovery and induction. One major disadvantage,though, is that it is difficult to acheive the desired plasma concentration bymanual control of the infusion rate. In order to maintain a constant flow theinfusion rate must be changed frequently. This is when the target controlledinfusion rate technique takes place. Target controlled infusion is what allowsthe anesthesiologist to set a desired plasma concen- tration, which the softwareinside the infusion pump produces rapidly, but safely by controlling theinfusion rate according to complex, but standard pharmacokinetic equations(basically medical equations). Remifentanil is a new potent, yet synthetic opiodthat is ideally suited for infusion during anesthesia. Unlike other opiods,remifentanil contains a methyl ester in its structure which causes a rapidmetabolism of the drug within the body. Remifentanil is now used as aneuroanesthetic and in the future will probably be used as a cardiac andcardiovascular anesthetic. Many advances have also been made in the medicalworld concerning local anesthetics. Amongst these local anesthetics, the mostpopular and up to date are bupivacaine and ropivacaine. Bupivacaine isfrequently used in postoperative pain releif. Induction to this anesthetic israpid and lasts very long. It can last for several hours depending on the dosegiven. The bupivacaine molecule exhibits stereoi somerism in each one of the twoenantiomers, which are R(+)bupivacaine and S(-) bupivacaine. The R(+) form ofbupivacaine is 3-4 times more likely to cause cardiovascular toxitity in rabitts,sheep, and humans. Ripovacaine is very similar to bupivacaine, but it is onlyprepared as S(-) ripovacaine isomer. Ripovacaine was proven safer thanbupivacaine in many clinical studies. Anesthesia has an unusual property. It isknown as the cutoff phenom- enon. The cutoff refers to the loss of anestheticpotency in the homologous series of alkanes and their derivatives when theirsize becomes too large. Apparently the potency increases with the length of thechain until the chain reaches fourteen carbons. At the fourteen carbon mark, theanesthetic has no potency whatsoever. The anesthetic potency increases rapidlyfrom a two carbon chain (ethanol) up to a ten carbon chain (decanol). From theeleven carbon chain to the thirteenth carbon chain the potency remains the same. When the carbon chain finally reaches the forteenth carbon, the potency suddenlydisappears. Scientists predict that this happens because the binding site is notlarge enough to accomodate long chained alcohols or because of the low watersolubility of longer 1- alkanols limits their access to the action sight. Scientists studied this through changing the 1- alkanol series to DPPC (dipalmitoyl-L-a-phosphatidylcholine). They did this through a procedure known ashydrogen bonding. Through hydrogen bonding transitional phases occured. In thesephases scientists proved that in between the transition of temperature, whichalso changed the state of matter, there was a certain point at which there wasno affect on the DPPC. Scientists also learned that the primary action site foranesthetics are the macromolecules of water. In conclusion C2-C10 are known asanesthetics and C14+ are known as nonanesthetics. In anesthesia, highpolarizability causes hydrogen bond breaking which causes anesthesia to work(e.g. cyclopropane). Also increased hydrophobicity along with relaxaion ofmembranes and proteins cause anesthesia to work. Anesthetics have manyadvantages. They are great in eliviating pain before, during, and after asurgical procedure. They also make the procedures much more easier. Anestheticsgive a desire d affect which is good because it helps us as a patient to relaxand feel calm and pleasant. Anesthetics have been around since the begging ofthe 1700s. Scientists have gathered a tremendous amount of informationconcerning anesthetics. Many advancements have been made and will continue to bemade. Throughout history man has searched for a way to stop pain. Whether it bea sore tooth or a broken limb, man has tried many different things to try and toget rid of that pain that he feels. The most modern way to eliviate pain isthrough the use of anesthetics. Although many of them have side effects, theyare improving and as long as our world and economy keep moving ahead andtechnologically advancing, we will be able to perfect all of the anesthetics. Inthe future there will prob- ably be new techniques used to administer anddistribute anesthetics, but for now these drugs seem to be doing the trick. Aswe enter into this new millennium, I hope to see more advances concerninganesthesia in this colorful world that we call the U.S. BibliographyAnesthesia: The Curing Sleep. Swift, W. Bradford. Cats Magazine. SouthDaytona . January 1990 Vol. 47, Iss. 1, Pg.17. Best Medicine: Under and Out. Saline, Carol. Philadelphia Magazine. Philadelphia. November 1988 Vol. 79, Iss. 11, Pg. 45. Anesthesia Cutoff Phenomenon: Interfacial Hydrogen Bonding. Chiou,Jang-Shin. Science. Washington. May 4, 1990. Vol. 248, Iss. 4955, Pg. 583-586. Tropospheric Lifetimes of Halogenated Anesthetics. Brown, A.C. Nature. London. October 19, 1989 Vol. 341, Iss.6243, Pg. 635-638. Anesthesiology-First of twoparts. Wiklund, A. Richard. The New England Journal of Medicine. Boston October16,1997. Vol. 337, Iss. 16, Pg. 1132-1142. An Anesthesia Mask Gas-ScavengingSystem. Schapera, Anthony. Journal of Occupational Medicine. Baltimore. November1993. Vol.35, Iss.11, Pg. 1138. Ludovici, L.J. The Discovery of Anesthesia. NewYork. Cone of Oblivion. 1961. United States Pharmacopeia. Complete DrugReference. Yonkers, New York. United States Pharmacopeial Convention Inc. 1992.
According to Arthur Holmes From a geological point of view soil may be defined as the surface layer of the mantle of rock-waste in which the physical and chemical processes of weathering co-operate in intimate association with biological procÃ esses (Principles of Physical Geology, Second Edition Completely Revised, the English Language Book Society Nelson). Arthur N. Strahler and Alan H. Strahler defines soil as a natural surface layer conÃ taining living matter and supporting or capable of supporting plants. Modern Physical Geography, John Wiley Sons, Inc. , Newyork). Chester R. Longwell Richard F. Flint defines soil as-Soil is that part of the regolith that will support rooted plants. (Introduction to Physical Geology, 2nd Edition, John Wiley Sons, Inc. New York, London). From the above definitions, it may be stated that- Soil is the surface layer of the earth restricted to land, consisting of a layer of broken-down, fine and loose rock material, produced by the weathering processes, mixed with decayed vegetation and other organic matter. Soil may be found on top of the parent rock or at some distance from it after transport and supports vegetation. The science which deals with the study of the soil is known as Pedology and the process of soil formation is called pedogenesis. The Soil Profile The pedologists have distinguished a number of layers or horizons within the soil. A vertical section made through a soil reveals a series of more or less distinct layers. These layers from the surface down to the unchanged parent material is called the soil-profile, which is characterÃ istic of the residual soil (i. . the soil developed on top of the parent rock), where there is a gradual transition from the top soils to the partially decayed rock and finally to the unaltered rock). But a transported soil does not show any such characteristic. A simple soil-profile shows three distinct layers designated as A, B and C- layer. The upper layer containing most of the organic material is called the A-layer or horizon, which is comm only known as the top- soil. This is the horizon of maximum biological activity. The layer below the A-horizon is the B-horizon, which is poor in organic content and rich in clay. This layer is regarded commonly as sub soil Mineral matter removed from the A-horizon through solution are precipitated in the B-horizon. High concentration of clay minerals in the B-horizon may be due to mechanical removal of colloidal clays in suspension by the descending soil water. Deposition of the ferro-humus material along with the silt and clay particles sometimes form a layer which is dense, tough and well cemented and is called a hard pan or clay pan. The C-horizon lies below the B-horizon. This horizon contains remnants of the parent material and is little affected by biologic activity. However, it is affected by physical and chemical processes. This horizon grades downward into the unaltered parent rock. Bedrock underlying the C-horizon is designated as R- horizon. Soil Formation The natural processes of soil formation are very slow; and are due to a combination of several factors such as 1. Parent rock material, 2. CliÃ mate, 3. Plant and animal life, 4. Local topography 5. Time etc. Most of these factors are interdependent. The processes of soil formation are most intimately associated with the weathering processes and the factors indicated above also determine the characteristics of the soil. 1. Parent rock material These are the bedrocks on which the soil develops. The processes of mechanical disintegration and chemical decomposition which constitute weathering proceed side by side resultÃ ing in the breaking down of the bedrock into a mixture of soluble and insoluble materials. While the soluble matter is removed in water, the insoluble residue forms a framework for the development of soil. Since the parent material or the bedrock is composed entirely of materials, it provides the inorganic constituents to the soil. The mineralogical composition of the bed rock from which the soil is derived, determines the rate of physical and chemical weathering as well as the composition of the soil. As we know, rocks composed of resistant minerals are slowly affected by weathering processes. Texture and structure of the parent material also determine the rate of weathring and the degree of retention of plant nutrients in the soil. 2. Climate Climatic conditions control weathering to a great extent. Climate of any particular region comprises elements like temperature, moisture including both humidity and precipitation, wind, air pressure, evaporation, and transpiration. Rainfall, as we know, is primarily dependent on the moisture content in the air and it varies from place to place with respect to its intensity, total amount in its distribution throughout the year. Heavy rainfall causes downward movement of water and soluble materials in the soil and the process is known as leaching. Leaching produces two distinct zones as:- (i) Zone of eluviation (i. e. washed out) in the A-horizon and (ii) Zone of illuviation (i. e. washed in) in the B-horizon. Climate gives rise to different soil types from the same parent material and also widely different parent materials may produce similar soils in one climatic context. Apart from rainfall, temperature plays a significant role in the weathering process. Temperature and moisture not only affect the rate of chemical weathering but also of bacterial activity, on the parent rock material in the process of soil-formation. 3. Plant and Animal life Many pedologists believe that soil is a biological phenomenon and that the plants play the leading role in the process of soil formation. Plants promote disintegration of rocks by the growth of trees in cracks or joints, thus wedging off large and small fragments of rocks. Roots often penetrate into the crevices of rocks exert on expanding force on the side walls. The biochemical activity of plants includes the extraction of various mineral substances, water and the necessary elements of nutriÃ tion on the one hand, and on their death and decomposition they contribute towards the accumulation of organic matter in the soil, on the other. Dead plants contribute to the humus content of the soil and the process of humification releases carbon dioxide and organic acids together with traces of ammonia and nitric acid etc. which often speed up the decomposition of the mineral matter and accelerates soil-formation. The microflora such as bacteria, algae and fungi contributes sigÃ nificantly to soil formation. But the activities of both bacteria and fungi are related to climatic conditions. In cold climates bacterial activity is limited whereas it is very intense and rapid in warm, moist climates. Bacteria are also involved in the nitrogen and sulphur cycles. Even the bacteria sometimes cause the quicker decay of neighbouring rock surÃ faces. Burrowing animals are effective soil makers. They make the soil and softer rocks porous and spongy and thus make them more readily susceptible to weathering and erosion. It has been estimated that earthworms completely work over a soil layer of 6 to 12 iches thick every 50 years. They extract vegetable matter from the soil by eating their way through it. As the soil passes through their bodies, it is subjected to mechanical and chemical modification. 4. Local topography It affects the character of the soil profile. True soils with a full profile can develop only on fairly flat surfaces where erosion is slow; whereas on steep slopes the profile never becomes completely developed as erosion removes the products of weathering as soon as they form. On flat upland surfaces, a thick soil is formed, often with a layer of clay, but it is well leached as uplands also attract heavier rainfall. On fiat-bottom lands in the flood plains, there is dark coloured, thick soils, since the flat bottom lands are poorly drained. 5. Time The development of a matured soil profile requires time. Soils are less well-developed if the soil-forming processes have not been in opÃ eration for an adequate time period for a fully developed soil-profile, in most places, it needs several thousands years.
Thursday, April 23, 2020
Narcolepsy Narcolepsy is a disease that has been on the receiving end of many jokes in our society. Yet it is a serious and life altering disease that is no laughing matter to the 1,000 in every 2,000 people in the U.S. that have it. I was drawn to this article because a former supervisor that I worked with had this disease. She was prescribed the drug Ritalin. It always impressed me that she could confront an angry client or give a speech without succumbing to the symptoms of her disease. She revealed that her case of narcolepsy wasn't that bad, but without the Ritalin she would just fall asleep anywhere. "The overall incident of narcolepsy is about 10 times that of Lou Gehrig's disease, half that of multiple sclerosis, five times that of cystic fibrosis, and about one quarter that of Parkinson's disease." Narcolepsy is a chronic disease, but not a progressive one. It is a puzzling neurological disorder that causes cataplexy, the loss of skeletal muscle tone without loss of consciousness, and persistent daytime sleepiness. Cataplectic attacks of narcolepsy can be triggered by exceedingly strong emotions such as laughter, embarrassment, anger, and athletic or sexual exertion. In tests on narcoleptic dogs, Emmanuel Mignot of Stanford and his co-workers identified a gene responsible for narcolepsy in dogs. "His research group determined that the dogs carry a mutation in the receptor for a neurotransmitter called hypocretin or orexin." These receptors are missing a critical part, so they can't respond normally to messages they receive. This is a recessive trait in the canines. However, they state that it is unlikely that most human narcoleptics have these mutated genes. Most narcoleptics have no narcoleptic relatives, and the disease does not occur until the second or third decade of life. Also, they have concluded that in 75 percent of the cases in which narcolepsy occurs in an identical twin, the other twin is unaffected. This, they say, indicates that environmental conditions are important in human narcolepsy. What environmental conditions are they? Damage to the hypocretin/orexin system due to environmental factors may mimic the symptoms caused by mutations. They feel that narcolepsy may be an auto-immune disease, in that the body turns against one of its own tissues are cell types. "The next step will be to determine whether the immune systems of narcoleptics are mistakenly targeting the hypocretin/orexin receptors in their own brains as foreign." according to Jerome Siegel. There are no concrete answers at the present time. Just hypotheses. Right now the only thing that science has to offer a narcoleptic is drugs to control their symptoms. For which I am sure that the sufferers of this disease are very grateful. We never seem to care about a disease until it strikes us or a loved one or friend. I'm thankful we have scientists out there who are working on answers to the causes and cures of various diseases, that hopefully, we may never have occasion to know about.