Japan Essay Example | Topics and Well Written Essays - 1250 words

Japan - Essay Example Japan is among the world’s most populated countries in the 21st century. The population of Japan is estimated to be approximately 125,000,000 according the recent population data available. Japan is a country that is made of several islands, which, are spread out in the Pacific Ocean. The main islands that make up Japan are, Kyushu, Hokkaido, Honshu and Shikoku. Japan is located in the Asian continent neighboring Korea, China and Russia. Japan has its southern most islands lying relatively at the same as Bahamas whereas its northern most islands geographically lies in similar latitude as Portland. Japan is preeminently an industrious country with a booming economy that has underwent numerous challenges over the decades. The major industries in Japan are reputably, electronics and automobile industries whose success has put Japan on the green light at the international economic stance. The Japanese products made their way to the international market after the Second World War with a high quality reputation and relatively low prices. The most significant industries that feature on the export of Japan are metal industry, aerospace industry, shipbuilding and biotechnology. The major problem facing the industries is the huge dependence on of raw materials from foreign countries. Japan is relatively inadequate supply of natural resources. The economy of Japan is inevitably influenced by its exports and imports. However, Japan has a good performance in economic freedoms among them business freedom, property rights as well as, freedom from corruption. Japan has a well-established modern financial sector. The economics of Japan has one shortcoming, huge public debt, which is considered to pose a challenge in reviving its stagnant economy. In addition, the disparities between various segments of the Japanese economy have widened continuously (countrystudies.us). Japan relies on its main export products are electronics, cars and computer devices for foreign exchange. Mostly, Japan exports its products to Taiwan, Hongkong, Singapore, Germany and Thailand. Japan obtains most of its raw materials imports from Australia, USA, Saudi Arabia, South Korea, the United Arab Emirates and Indonesia. The average annual income of Japan is approximately $ 60, 600 USD according to the survey by Japan labor ministry. The annual average inc ome of Japan decreases every year. This has been attributed to the fact that lifetime jobs are becoming less popular in the economy of Japan. The young people in Japan have a hard time securing a full time employment. The political instability of Japan and natural calamities such as the nuclear disaster are among factors that affect the Japanese economy tremendously. The economic meltdown caused by the nuclear disaster and the earthquake tragedy has rendered most Japanese companies financially unstable (kwintessential.co.uk). Japan is among the countries that boast of a diverse cultural setting with various religions and beliefs. The major religions in Japan are Buddhism and Shintoism. The Japanese population has customs and beliefs, which they hold on closely to day in day out. The most popular Japanese rituals originated from the rituals of Shintoism symbolizing hope and spiritual health for the members of the community. The origin of the Shintoism religion is not clearly traceabl e although there is archaeological evidence that suggests the Yayoi people first practiced it in the period (400B.C-250 A.D). The Yayoi people were made up of various clans with a god being associated to each. The gods represented nature objects such as rivers, mountains, rocks and storms. The Buddhism religion became established in Japan unimpeded in 587 A.D after the defeat of the â€Å" monohobe† clan that was opposing of Buddhism (afe.easia.columbia.edu). Japanese people have a major cultural belief, which involves an annual visitation of the dead by the members of their family. The festival is known as Bon Festival in which Buddhists visit temples

Ceramic Materials In Cutting Tools

Ceramic Materials In Cutting Tools Traditional cutting tools are mostly made of steels and irons, however, ceramic cutting tools are developed quickly these years. Ceramic cutting tools have a lot of advantages over other cutting tools in certain areas. Ceramics possess a lot of required properties for cutting tools such as high strength and good thermal conductivity. The development of ceramic cutting tools has once been hindered by the high cost and difficulty in manufacturing ceramics. Thanks to the improvement of materials engineering and the advent of composites, both the cost and the difficulty of manufacture have been resolved. The market share of ceramic tools has increased in recent years, which indicates that the ceramic cutting tools are well along in development. With a comparison and evaluation of many processing routes, die pressing and sintering are chosen as the most convenient and appropriate way for the manufacture of ceramic cutting tools. There are a lot of potential ceramic materials can be used in cutting tools and most of them are alumina or silica based. Composites have also attracted much attention with a relatively low cost and high performance. Cutting tools Cutting tools are designed to separate materials. They can be divided into different categories, each of which has its own characteristics and requirements for the materials used. The mostly used materials for cutting tools are steel and iron. However, with the development of materials science and engineering, ceramic cutting tools are playing a more and more important role. Ceramics are usually very hard, heat resistant and have little reactivity with steels, which are properties vital for cutting tools. Hence they can be used at high cutting speed without deformation and dissolution.[1] However, ceramics have their own drawbacks that they lack toughness and are sensitive to mechanical or thermal shock, which has limited the use of ceramic materials in cutting area. Humans have used ceramic cutting tools for more than 100 years. [2] The cutting objects vary from very soft substances (butter) to extreme hard things (steels). In the early days, the major composition of these ceramic tools was alumina. However, the toughness of alumina material then was low and softened by glassy phases, which were the reasons why their applications were limited. [1] With the effort of scientists, materials science and technology has dramatically developed so that the properties of ceramics have been greatly improved. They become harder by improving the purity, less brittle with some additives and tougher with reinforcements. [1] The first ceramic material used in cutting tools was Alumina. [1] A variety of other ceramics have also been produced to be specifically used in cutting tools manufacture. There are three categories available, namely pure oxide ceramics, mixed oxide plus carbide or nitride and silicon nitride based material. [2] Whisker reinforced ceramic materials, with high toughness and hardness at high temperature, has pushed forwarded the development of ceramic cutting tools. Figure 2.1 Cermet indexable milling tools [1] There are a lot of aspects that should be considered when the materials are chosen. The following three aspects were taken into consideration in the design of the tool material. [2] Firstly, the surface layer should possess the highest heat conductivity that is favourable for dissipation of cutting heat. Secondly, the thermal expansion coefficient of the surface layer should be the lowest of all the layers of the materials so as to form residual compressive stresses in the surface layers in the fabricating processing, which may partially counteract the stresses resulting from external loading. Finally, the value of maximum Von Mises stress should be the lowest in order to guarantee the structural integrity of the compact. [2] The properties of the ceramic are not the only factor involved in the material choice, the economic factor has also played an important role in the consideration of the material. [1] One of the main focuses in ceramic industry is how to cut the prime cost and the future developments most important direction must be cost reduction. New kind of raw materials and methods are needed to attain this goal. In the future, with the development of material science and technology, more methods will be used in improving ceramics. The perfection of coating technology and the progresses in composites will promote the usage of ceramics in cutting industry. CMCs (ceramic matrix composites) are considered to be one of the most popular materials used for cutting tools in the future. Current market situation There are three main cutting tools markets. Solid tools and indexable inserts; milling, turning and drilling tools are investigated to show the trend of current market of cutting tools. Grades include carbide, ceramic, cermet, CBN/PCBN, diamond and steel. Products are analyzed by country and end-use markets.[3] The consumer markets are specifically broken down by each of the following geographic regions: [3] à ¢Ã¢â€š ¬Ã‚ ¢ China à ¢Ã¢â€š ¬Ã‚ ¢ United States à ¢Ã¢â€š ¬Ã‚ ¢ Germany à ¢Ã¢â€š ¬Ã‚ ¢ Japan à ¢Ã¢â€š ¬Ã‚ ¢ Korea à ¢Ã¢â€š ¬Ã‚ ¢ Italy à ¢Ã¢â€š ¬Ã‚ ¢ France à ¢Ã¢â€š ¬Ã‚ ¢ Taiwan à ¢Ã¢â€š ¬Ã‚ ¢ United Kingdom à ¢Ã¢â€š ¬Ã‚ ¢ Brazil à ¢Ã¢â€š ¬Ã‚ ¢ Other EU à ¢Ã¢â€š ¬Ã‚ ¢ Other NAFTA à ¢Ã¢â€š ¬Ã‚ ¢ Other Europe à ¢Ã¢â€š ¬Ã‚ ¢ Other Asia/Pacific à ¢Ã¢â€š ¬Ã‚ ¢ Other Latin America à ¢Ã¢â€š ¬Ã‚ ¢ Rest of World The geographic regions from top to bottom represent the biggest markets for cutting tools. The United States Cutting Tool Institute which was formed when the Metal Cutting Industry and Cutting Tool Manufactures Association merged is now said to represent 80% of the domestic cutting tool market.[4] Great strides continue to be made in the cutting tool market that result in reduced bench time and additional handwork, as well as heavier depths of cutting which leads to increased productivity and higher accuracy. Over the past ten years the cutting tools market has increased dramatically. The tools have taken on very specific roles depending on the application. Now there are specific carbide grades, coatings and geometries to match the customers needs. The market is predicted to expand and grown and achieve new heights. [4] The majority of end users in industry of cutting tools are listed below: à ¢Ã¢â€š ¬Ã‚ ¢ Aerospace à ¢Ã¢â€š ¬Ã‚ ¢ Automotive à ¢Ã¢â€š ¬Ã‚ ¢ Chemical Processing à ¢Ã¢â€š ¬Ã‚ ¢ Communications à ¢Ã¢â€š ¬Ã‚ ¢ Construction à ¢Ã¢â€š ¬Ã‚ ¢ Defense/Military à ¢Ã¢â€š ¬Ã‚ ¢ Electronic à ¢Ã¢â€š ¬Ã‚ ¢ General Machining à ¢Ã¢â€š ¬Ã‚ ¢ Medical/Research à ¢Ã¢â€š ¬Ã‚ ¢ Oil Gas à ¢Ã¢â€š ¬Ã‚ ¢ Paper Pulp Industry à ¢Ã¢â€š ¬Ã‚ ¢ Power Generation Global market for cutting has been captured by the metal cutting tools for a long time. However, some special properties make the advanced ceramics tend to be more inexpensive, longer life, larger range of application, which become a competitive advantage for manufacturers.[4] Therefore ceramic cutting tools are expected to recapture the cutting market. The competition among manufacturers is expected to remain intense, which forces the manufactuers to work harder to get a smaller market share. The three largest competitors focus on carbide-tipped tools and carbide inserts worldwide. Current materials used There are four main ceramic compositions used in the cutting tool industry have been outlined below, the most important aspects of each material have been highlighted. [5] Sialons A sialon is a class of ceramic based on silicon nitride. The ceramic is composed of four different ceramic powders; silica (SiO2), alumina (Al2O3) and silicon nitride (Si3N4). The fourth component is either yittria (Y2O3) or magnesium oxide (MgO). The yittria is used to aid in the sintering process to increase efficiency of the process. [5] Sialons have very low coefficient of thermal expansion meaning that they are good in situations of thermal shock. Sialons are retain their hardness at temperatures of 800ÃÅ'Ã…   C to 1000ÃÅ'Ã…   C which enables them to be very effective when machining heat resisting alloys. They are also effective when machining hardened die steels and cast irons at high speed. [6] Aluminium oxide-based ceramics These ceramics are composed as their name suggests but are commonly found with small additions of zirconia (2-5%).the additional zirconia is added to increase fracture toughness. Al2O3 based ceramics show an increase in mechanical properties above 800ÃÅ'Ã…  C. Below this temperature the hard metals posses a greater strength than the ceramics. The hardness of the ceramic can be increased further by 30-40% with the additions of titanium carbide or titanium nitride. These harder ceramics are generally used for finishing and harder metals. Another common addition to the (Al2O3 + ZrO2) base are silicon carbide (SiC) whiskers at around 25%. The whiskers act as reinforcements to the structure and increase the toughness. This enables the ceramic to be used for cutting nickel based super alloys at high speed. [5] Silicon Nitride The ceramic has a density of around 3.2g/cm3 and the grain size is approximately 2-3 micrometres. Silicon nitride boasts good wear resistance and cutting edge strength as well as high resistance to thermal shock. Si3N4 is generally used in the field of providing a roughing grade for turning and milling cast iron. The bad solution wear properties of silicon nitride restrict the ceramic from being used as a cutting tool for machining steels. The high resistance to thermal shock means the ceramic can be used with and without the use of coolants. Money can be saved on cooling equipment in such a controlled manner. [5] Cubic Boron Nitride Cubic boron nitride is a synthetic compound, in its natural state it has a soft hexagonal crystal structure. Ton achieve a cubic structure it is heated to 1400ÃÅ'Ã…  C in 60kbar of pressure. This has a great effect on the hardness of structure, (Around 4000VDH) this is similar to diamonds hardness. [6] Carbon boron nitride is a polycrystalline and is used in applications where hard metals become limited by the cutting speeds employed. Examples are; high speed steels, tool steels, case hardened steels, chilled cast iron and satellite. Carbon boron nitrides hardness is second only to diamonds, for this reason carbon boron nitride offers great wear resistance and the ceramic will not need to be replaced on cutting tools as much as others. Harder metals are also possible to machine with more efficiency, however carbon boron nitride offers no advantage when machining softer materials. [5] Composites The properties of ceramics are dramatically improved by using some sizes, such as TiC, Co and WC, as dispersed phase, named composite ceramics. The type composite ceramics is the Si3N4 composite ceramics, which hardness, bending strength and toughness is higher than the simple Si3N4-based ceramics. It also has a better thermal impact resistance. Because of its special properties, it is widely used in machining cold hardened cast iron roller, and it can finish the work of coarse and precise machining of roughcast, for overcoming the low machining hardening of steel parts used in the mining facilities. Its disadvantage is poor abrasion machining. [6] Coating material Coating technology plays a very important role during the cutting tool manufacture. It is used to produce the perfect cutting tools which have both hard surface as well as high toughness. With the development in the last 10 years, this technology has made materials with high-speed cutting, hard cutting and dry machining possible. Cutter coating can be divided into four kinds. They are chemical vapor deposition (CVD), Low-temperature chemical vapor deposition (PCVD), Middle temperature chemical vapor deposition and PVD. However, cutting tools are expected to be coated differently to meet the demands for comprehensive mechanical properties. Therefore more attention should be paid to make coating thinner and coating temperature lower. [6] The future materials The future of ceramic cutting tools is dependent on the development of super hard coatings for the cutting tools. A new coating for a ceramic cutting tool is a titanium aluminum nitride coating. The coating helps to control the temperature of the cutting tool when it is used at high speeds. This allows for quicker cutting and therefore a more efficient process. [6] The coating also adds to the lifespan of the tool, in some cases it can make the tool last several times longer. It is important to note that the addition of the coating also adds 10% to the cost of the tool although this is immediately recovered by lasting much longer. [7] Possible processing route Most of the ceramics are processed by shaping and sintering. The shaped ceramics are called green body. The shaping process of ceramics is crucial as it can influence the properties of the sintered products such as porosity. Nowadays, the main methods of forming ceramic green bodies include die pressing, slip casting, pressure casting, and injection molding. Shaping All the methods above start with a suspension where the ceramic particles are mixed with a liquid or a polymer melt, proper dispersant, and possibly further additives such as binders, plasticizers, and antifoaming agents so that a well-dispered, nonagglomerated ceramic slurry can be made. Die pressing can be divided to many different pressing route such as dry pressing, cold isostatic pressing and hot isostatic pressing. Green bodies are manufactured by pouring powders into the die and these granules are formed under certain pressure. [8]The method of dry pressing is almost as the same as the cold isostatic pressing. The two methods are widely used in the industrial production of ceramic materials, accounting for their productivity ,and the development of cold isostatic pressing makes green bodies of higher density possible. Slip casting and pressure casting are included in the drain casting techniques, which invovle a solid-liquid separation process to form a dense green body. [8] The driven force of flow liquid in the two castings is an external pressure gradient. [8] Slip casting is a low-pressure filtration of which the driving force provided for the green bodies forming is the capillary suction.[9] slip casting is slow compared with die pressing but complex figure can be obtain. Pressure casting is usually used to fabricate the traditional clay-based ceramic materials, such as pottery and sanitary porcelain. [9] Pressure filtration is an improved method of slip casting, the casting rate is raised and the green bodies have a higher density. [9] Both die pressing and casting are plagued by some genetic problems. The liquid flow of the suspension is required and the stress gradient may also lead to nonuniform densities of the green body which lead to the pockety mass.[9] Injection molding is an excellent method to form smaller objects. The mixture of powders and binder are intruded to the mould and form green bodies. [9] However, the removal of the binder which can be burned at relative low temperature has been a problem. Crack and imperfections will be introduced during this procedure. [8] There is also a technique called solid freeform fabrication(SFF) by which we can form a ceramic green body without using a mould. All the process is controlled by computer using 3D CAD designed before the process.[10] This method have been used to form complex figures, however, the surface finish is poor. [9] This method has not been widely used for its immature technology. Sintering After shaping, the density of a green body is usually about 50% of its theoretic density. Full densification can be achieved by sintering at temperature up to 1800 °C.[11] During this process, individual powder particles can get enough energy to bond together realize the transformation from the porosity present to the compaction stages. Composites processing Composites are consisted of two parts: the matrix phase and the reinforcing phase. Generally, the combination of the two parts is achieved through a melding event. After the melding event, the part shape is set. According to the melding event, the methods of composites preparation can be classified into four main methods ¼Ã… ¡vacuum bag moulding, pressure bag moulding, autoclave moulding and resin transfer moulding (RTM).[12] Besides, there are some other types of moulding that include press moulding, pultrusion moulding, filament winding and so on. [12] Composites can also be devided into metal matrix composites(MMC) and ceramic matrix composites(CMC) based on the matrix materials. According to the temperatrue of metallic matrix during processing, the processes of MMC can be classified into five categories: [14] 1).liquid-phase processes, 2).solid-liquid processes, 3).two-phase (solid-liquid) processes, 4.) deposition techniques 5) In situ processes. The selection of materials and processing route Then dry processing has much influence on the green microstructure and production rate. We must treat this opreation to avoid the problem of cracking and warping. The desired result in ceramic part production is fast drying, but fast drying causes cracking. It has been studied that decreased drying rates results in the increasing green densities. The size of power also affects ceramics sintering properties. These days, nonasized powder attracts much attention, because of its special properties (mechanical, optical, magnetic and electrical). The compacts of nanosized powder can be sintered at significantly reduced temperatures, thereby lowing the firing cost.[10] And it is possible to get high density ceramic body in the formation of nanosized particles.[11] From the ceramics already discussed the best ceramic to use for this product would be the Aluminium oxide-based ceramic. It is already widely used in the industry so there is no need for testing to make sure it works. When cutting the cutting tools increase in heat rapidly, sometimes this has an effect however with Al2O3 their mechanical properties get better the hotter they get. The ceramics hardness will also be increased further with addition of silicon carbide whiskers. These whiskers add reinforcement to the structure and increase it toughness. Therefore the cutting tool can be used at higher speeds. Not only will our ceramic have added strength from the whiskers but with have a tough outer shell from a coating of TiAlN. This coating has a high bond strength, high hardness, abrasion resistance and high cutting speed.[8] From all of the possible processing routes in the industry, it has been decided that Dry Pressing would be the route which is most beneficial to the company. Dry Pressings most appealing feature is the productivity factor. Its fast productivity means that the product quantities are increased therefore meaning that costs will be reduced. Ben Franklin one said Time is money, he was right. Reducing production times reduces the amount of time staff needs to work, it reduces the amount of time that machines have to be on, and therefore it reduces the costs of production. Dry Pressing is conducted with granulated or spray-died powder containing 0 to 4% moisture which is where Dry Pressing gets its name from.[1] There are some disadvantages of using this process but the many disadvantages overrule this fact. One of these disadvantages is that high pressures are used in the process, but then again these high pressures are not as high as the ones used in pressure casting. Dry pressing can only gain good results if all the steps prior of the forming or pressing is kept under careful control. The product once leaved the die cavity is in a plastic condition and if not handled carefully, may deform. With dry pressing there is no limit to the compositions which can be used because the plasticity of the body is not relied on to aid the forming. Under normal conditions and supervision it is possible to produce ceramics to very good tolerances. In special cases with very close controls tolerances can be kept which are considerably better than usual. Slip casting is in need of too much careful control to be able to mass produce at a beneficial production rate, especially with the long time it takes to cast articles on the mould. Pressure casting is pretty much the same as slip casting but with added pressure to speed up the casting time. This added pressure is not justified because it is too expensive and does not take enough time off the process. Injection Molding has a few defects, which can occur to the product. There can be an incomplete fill within the mould, knit lines, and microcracking, which will all, have a visual defect on the finished body. Concluding, the dry press process has the least amount of possible defects to occur in comparison to other process routes. It is the quickest route with great productivity and can offer very high tolerances. These are the main reason for our choice of dry pressing process route. 7. Reasoned argument for RAC The ceramic that has been selected to be taken forward is Al2O3 + (2%Zr) + (20%SiC whiskers), there is no issue in using this composition legally. However the methods of using the cutting tool must be reviewed as such patent 4,879,277 which claims . In a method of cutting metal wherein a cutting tool is brought into contact with a metal workpiece and the cutting tool and metal workpiece move relative to each other whereby metal is removed by the cutting tool from the metal workpiece, the improvement comprising using a sintered composite cutting tool having a matrix consisting essentially of alumina and 2-40 volume percent silicon carbide whiskers distributed therethrough. [14] A work around the patent would have to be implemented if the material is to be used in such a way. A variation in whisker content or physical machining could help to deviate from the patents claims. RAC could create a competitive edge for themselves by proceeding with this option as it will help them to differentiate themselves to most of their competitors. The material selected is a very cutting edge material with extremely high levels of performance. Many of the competitor businesses would not have adopted this material and may continue to use a lesser and cheaper material such as unreinforced aluminium oxide based ceramics. RAC will be able to offer a faster and more efficient cutting solution to their clients. The superior technology is likely to attract new customers to the business leading to a larger market share. The harder cut edge and faster cutting speed will lead to a greater cutting quality also, the tools will be able to be smaller in size and so more precise machining is possible. The business will be able to supply their service to a wider range of clients requiring different finishing qualities. From the market analysis carried out previously it is clear that the cutting tool industry is a blooming one. It is encouraging that the market has grown so dramatically over the last ten years and that there is an increased demand for new cutting tool technologies. The need for faster and more accurate methods will remain the same as the products on the market continue to develop in complexity. To conclude the ceramic and manufacture process put forward can be projected to be a positive step for RAC after considering the factors involved. The only problem to resolve before proceeding with the decision is the patent on the ceramic and its method. Once this is resolved the decision to proceed is an easy one and should lead to business success.

Main Economic Forecasts Essay -- Economics Economy Economical Essays

Main Economic Forecasts   Ã‚  Ã‚  Ã‚  Ã‚  The main economic forecasts used to understand the general outlook of the economy included the Congressional Budget Office (CBO) forecast, the Administrations Forecast, the Blue Chip consensus forecasts and the Mortgage Bankers Association (MBA) forecast. Not all forecasts contained the required indicators for the chosen indicators: employment growth, interest rates, housing starts, and business investment. For this reason, the analysis focused on a combination of the forecasts to understand the relationships among the indicators. Gleaning the economic forecasts led to a general understanding of the economy. Conducting further research on the economic forecasts led to a richer understanding of the selected indicators. The focuses of the economic forecasts were real gross domestic product (GDP) and unemployment. The selected forecasts discussed real GDP and unemployment in depth to give the reader a general understanding of how the economy might respond in the next two years. According to the MBA, real GDP will drop in 2005 in comparison with 2004 and continue to decrease in 2006. In 2007, real GDP will increase slightly in comparison to the previous year. The MBA states the percent change in annual rates will be 4.4 in 2004, 3.8 in 2005, 3.3 in 2006 and 3.5 in 2007. According to CBO, real GDP will decrease in 2005 compared to 2004; GDP will decrease further in 2006 and continue to decrease during the 2007 through 2010. The CBO states the percentage change of real GDP was 4.4 in 2004, will be 3.8 in 2005, 3.7 in 2006 and 3.3 on average for the years 2007-2010. The Blue Chip consensus believes real GDP will decrease in 2005 compared to 2004, and continue to descend for the next two years, 2006 and 2 007. Blue Chip consensus states real GDP for 2004 as 4.4, 2005 will be 3.7, 3.4 in 2006 and 3.5 in 2007. The President’s administration believes real GDP will decrease in 2005 compared to 2004 and will continue to decrease in the next two years as well. According to the President’s administration, real GDP for 2004 was 4.4; and will be 3.7 for 2005, 3.7 for 2006 and 3.5 for 2007. The MBA believes the unemployment rate will decrease from 5.5 in 2004 to 5.2 in 2005 and continue to descend to 5.1 in 2006 and 2007. The CBO believes that unemployment will decrease from 5.5 in 2004 to 5.2 in 2005 and remain at 5.2 through 2010. Blue C... ...f Commerce. Bureau of Economic Analysis. Retrieved April 20, 2005 from http://www.bea.doc.gov/ Housing and interest rate forecast. National Association of Home Builders. Retrieved April 21, 2005, from http://www.nahb.org/generic.aspx?sectionID=138&genericContentID=631&print=true HR compensation continues to rise: Rising compensation reflects an improving economy and HR's role in corporate growth. HR Magazine. Retireved from http://www.findarticles.com/p/articles/mi_m3495/is_11_49/ai_n6359691 MBA long-term economic forecast. Mortgage Bankers Association. Retrieved April 20, 2005, from http://www.mortgagebankers.org/ MBA long-term mortgage finance forecast. Mortgage Bankers Association.. Retrieved April 22, 2005 from http://www.mortgagebankers.org/ MBA is most accurate. Federal Reserve of Atlanta. Retrieved April 24, 2005 from http://www.census.gov/ The budget and economic outlook: An update. Congressional Budget Office. Retrieved April 20, 2005 from http://www.cbo.gov/ Real investment in fixed assets and consumer durable goods, 1999-2003. U.S. Department of Commerce. Bureau of Economic Analysis. Retrieve April 20, 2005 from http://www.bea.doc.gov/

Hunger Games Character Paper

The Hunger Games- Character Paper I read the book The Hunger Games by Suzanne Collins. The book is about the future and how the central government overrules all of districts, Panem. The main character of the book is Katniss Everdeen. She is a teenage girl who lives in â€Å"District 12†. Her district is known for all the coal mining; she had lost her father when she was younger in mine explosion.After this she had to step up and be the adult. She is very brave and she is very smart. Katniss, the story's narrator and heroine, is 16 years old and has straight black hair, gray eyes, and olive skin. Her father died in a mine explosion when she is 11. Since then, to keep her family from starving in the Seam, she has had to provide for her mother and sister, using the hunting and gathering knowledge that her father taught her.Her best friend and hunting partner is Gale, and, while they spend a great deal of time together, Katniss is sure that she doesn't see him in a romantic light, something that comes into deep question when she is District 12's Hunger Games tribute and must work hard to maintain a star-crossed-lovers facade with Peeta Mellark. Throughout the novel, she remains a hunter and a survivor, â€Å"the girl on fire,† but she is also a girl who is very confused about her emotions concerning Peeta and Gale.Katniss must also remember to hide her true emotions about the Capitol: She loathes the Capitol and its tyrannical rule, but to rebel openly is to ask for punishment, oftentimes death. She is brave and daring and returns home from the Games a beloved star to her district but a menace to the Capitol dictators in charge of Panem. Katniss is very relatable to young girls because of her confusion with boys. This makes Katniss a great main character for the book because who doesn’t love a science fiction book with a relatable main character?

The Twilight Saga 2: New Moon PREFACE

Summary When the Cullens, including her beloved Edward, leave Forks rather than risk revealing that they are vampires, it is almost too much for eighteen-year-old Bella to bear, but she finds solace in her friend Jacob until he is drawn into a cult and changes in terrible ways For my dad, Stephen Morgan No one has ever been given more loving and unconditional support than I have been given by you. I love you, too. These violent delights have violent ends And in their triumph die, like fire and powder, Which, as they kiss, consume. Romeo and Juliet, Act II, Scene VI PREFACE I FELT LIKE I WAS TRAPPED IN ONE OF THOSE TERRIFYING nightmares, the one where you have to run, run till your lungs burst, but you can't make your body move fast enough. My legs seemed to move slower and slower as I fought my way through the callous crowd, but the hands on the huge clock tower didn't slow. With relentless, uncaring force, they turned inexorably toward the endthe end of everything. But this was no dream, and, unlike the nightmare, I wasn't running for my life; I was racing to save something infinitely more precious. My own life meant little to me today. Alice had said there was a good chance we would both die here. Perhaps the outcome would be different if she weren't trapped by the brilliant sunlight; only I was free to run across this bright, crowded square. And I couldn't run fast enough. So it didn't matter to me that we were surrounded by our extraordinarily dangerous enemies. As the clock began to toll out the hour, vibrating under the soles of my sluggish feet, I knew I was too lateand I was glad something bloodthirsty waited in the wings. For in failing at this, I forfeited any desire to live. The clock tolled again, and the sun beat down from the exact center point of the sky.

The Definition of a C Algorithm

The Definition of a C Algorithm In general, an algorithm is a description of a procedure that terminates with a result. For example, the factorial of a number x is x multiplied by x-1 multiplied by x-2 and so on until it is multiplied by 1. The factorial of 6 is 6! 6 x 5 x 4 x 3 x 2 x 1720. This is an algorithm that follows a set procedure and terminates in a result. In computer science and programming, an algorithm is a set of steps used by a program to accomplish a task. Once you learn about algorithms in C, you can use them in your programming to save yourself time and to make your programs run faster. New algorithms are being designed all the time, but you can start with the algorithms that have proven to be reliable in the C programming language. Algorithms in C In C, the designation identifies a group of functions that run on a designated range of elements. The algorithms are used to solve problems or provide functionality. Algorithms work exclusively on values; they dont affect the size or storage of a container. Simple algorithms can be implemented within a  function. Complex algorithms might require several functions or even a class to implement them. Classifications and Examples of Algorithms in C Some algorithms in C, such as find-if, search, and count are sequence operations that dont make changes, while remove, reverse, and replace are algorithms that modify operations. The classifications of algorithms with a few examples are: Non-modifying sequence modifications (find-if, equal, all_of)Modifying sequence operations (copy, remove, transform)Sorting (sort, partial sort, nth_element)Binary Search (lower_bound, upper_bound)Partitions (partition, partition_copy)Merge (includes, set_intersection, merge)Heap (make_heap, push_heap)  Min/max (min, max,min_element)   A list of the most common C algorithms and example code for many of them are available online in C documentation and on user websites.

The Benifits of Gum essays

The Benifits of Gum essays What I know- I do not know a lot about gum, which is why I want to research it further. I know that gum tastes very good and many people like to chew it. Early document action of gum says the Native Americans told the American Colonists about chewing on resin from spruce trees. Gum stimulates the saliva glands which is why it is actually good for your teeth. This is why the Native Americans told the Colonists about gum. Though gum is no substitute for brushing your teeth, if it is the only way you can clean them then it is good for a short term fixer. Gum comes in all different sizes flavors and colors. Some of the flavors are spearmint, peppermint, cinnamon, and winterblue mint, the original bubble gum, and all the other bubbleitious and bubbleyum flavors. Most people would not think that gum is an interesting topic to research. I wanted to learn more about gum. How it is made? Which flavor lasts longest? Which company makes the best gum, and how are gums different? These are some of the questions I want to answer in my research paper. I also would like to answer the question, is gum actually good for you? The problem of this I-search is that no one knows which gum flavor lasts the longest. By the end of my research I want to be able to know the answer to that.. Answering these questions will allow me to know more about what gum I should chew. I can find out which gum is healthiest, which gum flavor will get me though the day, and which company makes gum whose flavor that will last. Wrigleys gum is made with a long process. The beginning to making gum is melting and purifying the gum base. Next the melted base is mixed into a large mixer. Then sweeteners and flavors are added while the gum is being slowly mixed. A large loaf of gum is sent through a series of rollers, until it is the thi ...

The Growing Problem of Road Rage

The Growing Problem of Road Rage Statistics tell us that most all of us have been involved in an aggressive driving experience either as the victim or the aggressor at some point in our lives. Aggressive driving and road rage is on the rise, and according to the AAA Foundation for Traffic Safety (AAA), it is one, if not the top concern for many drivers today. AAA reported that at least 1,500 people a year are seriously injured or killed in senseless traffic disputes. The following includes excerpts from a report issued by the National Highway Traffic Safety Administration. Characteristics of Aggressive Driving The term aggressive driving emerged during the 1990s as a label for a category of dangerous on-the-road behaviors. The category comprises: Following too closelyDriving at excessive speedsWeaving through trafficRunning stop lights and signs Aggressive driving occasionally escalates to gesturing in anger or yelling at another motorist, confrontation, physical assault and even murder. Road Rage is the label that emerged to describe the angry and violent behaviors at the extreme of the aggressive driving continuum. Graduating From Traffic Violation to Criminal Offense The NHTSA defines aggressive driving as, The operation of a motor vehicle in a manner that endangers or is likely to endanger persons or property. An important distinction is that aggressive driving is a traffic violation, while road rage, aside from the yelling and gesticulating, is a criminal offense. Contributing Factors To Aggressive Driving Experts suggest many reasons for the increase in aggressive driving and road rage. Sociologists suggest it is due to the breakdown in our societys sense of community and a disintegration of shared values.Psychologists point to the intoxicating combination of power and anonymity provided by motor vehicles.Traffic engineers tend to believe the problem is due to inconsistent driving speeds among travelers. Traffic Congestion Traffic congestion is one of the most frequently mentioned contributing factors to aggressive driving. Drivers with low tolerances for traffic delays might respond by following too closely, changing lanes frequently, or becoming angry at anyone who impedes their progress. Running Late Some people drive aggressively because they have too much to do and are running late for work, school, their next meeting, lesson, soccer game, or some  other appointment. Many otherwise law-abiding citizens often justify speeding when running late, almost as they would a medical emergency. Speeding because one is running late to pick up a waiting child or getting an elderly parent to a doctors appointment is often deemed as okay in the minds of even some of the safest drivers. Anonymity A driver can develop a sense of anonymity and detachment when insulated within the privacy of a vehicle. Tinted windows further detach drivers, adding to the misconception of being an observer of the surroundings, rather than a participant. The anonymity for some may provoke antisocial behavior unseen in other normal interaction they experience with others. Combine this with having the power of a motor vehicle and the knowledge that it is unlikely they will ever be seen again by those they offend and the result can be extreme rudeness and even turn an otherwise nice person into a dangerous, raging individual. Disregard for Others and for the Law Much has been written about the erosion of shared values and respect for authority, variously attributed to the fragmentation of the extended family, increased individual mobility, media influence, and other characteristics of modern society. It does appear that civility and respect for authority have decreased, the trend epitomized by the phrase, Im just looking out for number one. Habitual or Clinical Behavior Most motorists rarely drive aggressively, and some never at all. For others, episodes of aggressive driving are frequent, and for a small proportion of motorists, it is their usual driving behavior. Occasional episodes of aggressive driving might occur in response to specific situations, such as speeding and changing lanes abruptly when late for an important appointment, when it is not the drivers normal behavior. Among the chronic aggressive drivers there are those who learned the driving style and consider it appropriate and others who may have learned to drive properly, but for whom the behavior is an expression of illness. Clearly, it is a matter of degree and not all anger is uncontrolled, or even inappropriate, that is, it is not the anger, but what a person does about it that matters (e.g., anger that motivates a person to call the police when encountered on the road by an obviously impaired or dangerously aggressive driver). However, chronic anger, habitual or persistent aggressive driving, and especially a pattern of confrontation on the road, must be considered manifestations of pathology, in addition to violations of the law. Sources:National Highway Traffic Safety AdministrationRoad Rage: Causes and Dangers of Aggressive DrivingAAA Foundation for Traffic Safety

William Apess and Frederick Douglass Research Paper

William Apess and Frederick Douglass - Research Paper Example William Apess and Frederick Douglass were both men who accepted and adhered to the Christian faith while championing social causes for their people. William Apess is a Christian minister and missionary who works among his people and fights for their recognition of their status as worthy human beings. Apess’ writings â€Å"illuminates the meaning of the colonial and post-colonial relationship between Native Americans and the white dominant culture as well as an understanding of the violence that permeates that relationship† (Moon 45). Equally, Frederick Douglas is an ex-slave who was educated and sought to sensitize the American public on injustices against slaves and African Americans. Both men persist in laboring as advocates of human rights through their writings. Their writings classified as protest writing â€Å"found enthusiastic supporters among the entire literate black population whose resentment and indignation it voiced†¦the motivating force was that onc e they became aware of the situation, the powerful white minority would do something to improve matters† (Gaylard 20). Composed during the Abolitionist Movement and Reconstruction Era, these literary works stress the superficiality and hypocrisy of the Christian Whites in their support of institutionalized, discriminatory oppression - employing their own ideologies and religious doctrines to control the masses. The superficiality of the White man's doctrine is a point of argument in Apess' work. Apess observes that one â€Å"may learn how deep (the White man's) principles are...I should say they were skin deep† (Apess). The foundation of the objections to non-Whites’ enjoyment of their human dignity and privileges is based on the skin pigmentation. Skin color has no inherent value in any substantial and profound argument since what lies on the inside forms the core and matters most. Contrary to the racial Whites, Apess’ major concern is â€Å"†¦not talking about the skin, but about principles† (Apess). In his day, Apess would have been familiar with the Great Chain of Being philosophy which privileges the Whites at the head of the human race and relegates the Other to occupy lower tiers (Lovejoy 27). American Whites manipulated this concept to justify their subhuman treatment of other races. Frederick Douglass also perceived the superficiality of racism re alizing that â€Å"there was a skin aristocracy in America; no not exactly the skin, it was the colour of the skin, that was the mark of distinction or the brand of degradation† (Blassingame 50). Greed and prejudice constitute the vices that spurred discrimination. As a consequence, millions have lived broken lives and died deaths worse than an animal’s. The slavery was founded on skin color without regard for other more sterling and lasting qualities such as character. Douglass marvels at the preoccupation with something so trivial, yet which bears so much weight. The usage of skin color as a means to exalt oneself and debase another reveals the superficiality of the premises of racism. In time, the surface of any object is defaced and gradually stripped away. External appearances deceive however, only the content of character is real and enduring. As a Christian minister himself, Apess makes a stirring appeal to the tenets of Christianity, the so-called White man's r eligion. White men would use their religion to validate conquest, segregation, and the institution of slavery, however, Apess wields the Holy Bible, the book which instructs Christians in defense of human rights, equality, justice and brotherhood. Apess cites in his stirring appeal that â€Å"God is no respecter of persons; †¦By this shall all men know that they are my disciples, if ye have love one to

1973 Chilean coup d'tat Research Paper Example | Topics and Well Written Essays - 750 words

1973 Chilean coup d'tat - Research Paper Example The poems of this artist were conveying the message of the dilemmas of being deep-seated in a brutal, harsh and oppressive political establishment. When he was released from custody, Zurita facilitated the establishment of group of radical artists that was against the oppressive acts of Pinochet. In his writings, Zurita rolled out the prevailing conditions that were there before the coup, during the coup and what followed after the coup. The coup was carried out three years after Salvador Allende was elected president of Chile (Zurita 25). Salvador was the person in charge of the Chilean Socialist party, and he became the first president to be elected to office through a free and fair, diplomatic election. Salvador’s government experience grave economic tribulations with very high rates of inflation and unemployment. He developed strategies that would control these problems including price con trolls and nationalization of industries and firms. He also reinstated the diplomatic relations with the neighboring countries (Zurita 29). Everything was running smoothly, and all artists including young Zurita had a lot of freedom to do all manner of arts, until Salvador appointed Augusto Pinochet as commander in chief of the Chilean army. With the help of the CIA, Pinochet plotted to overthrow the Salvador’s government through a military coup on September 1973 that left Allen de dead (Zurita 32). What followed Augusto’s victory was what Zurita responded to in his writing. The Chilean parliament was closed down, and the constitution was suspended. Further, Augusto debarred all the political actions, and the trade union agreements that existed as well as strictly muzzling the media. Augusto allotted himself as the president, and he ordered the killing of more than of Salvador supporters. Anyone who was suspected of holding liberal meetings was either suspended from their job or jailed

M chap 3 Coursework Example | Topics and Well Written Essays - 250 words

M chap 3 - Coursework Example scale and large scale businesses may always employ certain approaches as well as techniques relevant to changes in consumer behavior (Dietrich and Media, 2015)s. In marketing, businesses always need to acquit themselves with certain information from their consumers including their locations, what they want, as well as who their real consumers are. Changes in consumer behaviors always make businesses to conduct thorough researches, as well as, surveys in order to know what the consumers want. For example, in case they fail to satisfy the changing consumer interests and needs, marketing of such products may be compromised and can easily fail. As such, the businesses always conduct surveys and research through sales forecasts, internet researches, as well as, market sensing (Dietrich and Media, 2015). This gives them a competitive advantage in the marketing spectrum as they deeply understand the needs of their customers, failure to which, can lead to failure of the companies. It is important to note that the issue of consumer behavior is also affected by the economy of the United States in certain ways. For instance, if the economy strengthens, the consumer demands and tastes increases (Rao, 2010). However, if the economy faces some crises, the consumers also feel these economic crises, thereby limiting their consumption demands. It is of critical significance to note that changes in consumer behavior are not influenced by any legislation. This is because consumer behaviors are majorly dictated by their own personal interests, tastes and preferences. As such, it is important to note that consumer behavior can affect the market in various ways. According to my opinion, consumer behavior always controls the markets in various ways. as such, the changes in consumer behavior can always make some companies to experience big losses if they do not device effective marketing strategies to approach the situations occasioned by the changes in consumer behaviors. Therefore,

Strategic Management Pharmaceutical Essay Example | Topics and Well Written Essays - 500 words

Strategic Management Pharmaceutical - Essay Example Pfizer Inc. pays a special attention to the product mix and geographical location (Johnson, Scholes 1998). Pfizer Inc. follows two pathways: growth with the same products in the same markets and development of new products for the same markets. Pfizer Inc follows vertical-integration which allows the company to integrate upwards. Also, growth strategy involves HRM and resource location aimed to meet the highest industry requirements and customers' demands. It was stated above that marketing departments work more closely with R&D departments to ensure that the products which are developed are those which cater for the changing needs of target customers and different needs of varying customer segments. In recent years, high failure rates in the introduction of new products have led departments to be very risk averse, with most 'new' products emerging being merely extensions of existing product lines and not truly new and innovative offerings. Its best selling and innovative products in clude Lipitor, Diflucan, Zithromax, Viagra, Celebrex etc.

Talent Management Strategy Research Paper Example | Topics and Well Written Essays - 1500 words

Talent Management Strategy - Research Paper Example The current employment size of the organisation in over 20,000 people worldwide and the company is continuing to expand into newer markets. The company has come a long way from its humble origins in the early forties when it was founded in a small state in Europe. Currently Hilti operates in over 120 countries worldwide and tends to operate in one of the most competitive markets in the world (Hilti, 2009). In order to gain competitive advantage over its competitors Hilti has a continuous need for innovation that it tends to meet using talent management methods. The added pressures to make the workplace safer have meant that health and safety regulations have been changing around the world in the past few decades (Fung et al., 2010). In order to keep up with the challenge, Hilti has been employing a number of different talent management strategies that are discussed in detail below. 2. Talent Management Strategy Talent management has grown to encompass human resource management throug h the active anticipation of human resource requirements. These requirements are tabulated and plans are devised in order to meet the identified human resources needs (Carpenter, Bauer, & Erdogan, 2010). Generally businesses engaged in talent management transfer the grooming of employees from the human resources department to the line managers directly in order to produce more efficient strategies. It also tends to make more sense given that the line managers have far greater expertise in determining the needs and requirements of individual employees. These can be used to align the development of individuals with the developmental needs of the organization far more flexibly. The largest reason for the enhanced flexibility is the simplification of the overall framework that does not remove the human resources department but instead tends to simplify the process flow. Typically talent management programs can pursue either of two preferred paths in order to enhance the overall human re source potential. The simpler strategy is to hire talented individuals from the labor market and to manage them accordingly. Another alternative strategy is based on the assumption that all individuals carry some form of talent. This strategy relies on grooming the individual talents of all employees in order to garner human resources. Therefore, talent management in an organization could be diverted at a select few individuals or to the entire labor set in order to develop human resources to empower the organizational objectives and goals (Rammer et al., 2010) (Perdomo-Ortiz et al., 2009). While some organizations have chosen to pursue the former path over the latter but Hilti has chosen to use the latter path. The development of a few select individuals tends to lower the costs for talent management but exposes the business to greater risks. These risks arise when the talented and groomed individuals choose to leave the organization for any number of reasons. Above anything else, this could occur due to the â€Å"war for talent† (Michaels, Handfield-Jones, & Axelrod, 2001) where an organization decides to capture the available talent pool from the market by providing better pays and perks. The human resources that leave an organization in this scenario represent a large

Summary Essay Example | Topics and Well Written Essays - 500 words - 87

Summary - Essay Example Some require a little time in the evening, especially on the direct hire side. I usually work anywhere from 8am to 9pm, sometimes even 10 pm. Most of my time is spent with sourcing candidates, either on LinkedIn or social networking. The rest of my time is spent working with the marketing side of things so that we can better attract candidates. It is not really that difficult because if a candidate is qualified then we obviously move forward with them. However, if there are some red flags then we will check them out to make sure that they are going to be a good candidate. On the marketing side, it can be easy if it is a company that is willing to build a relationship with us. There may be positions and opportunities that we want to work with them on so then we move forward with them on that. The difficulties often come from a business standpoint, but very rarely from the recruiting or marketing side. It depends on each company that we work with. It also depends on what their criteria is and the type of skill sets that they are looking for in their environment. As you can understand this varies from position to position. There is not only one set list of criteria that is used to determine whether to make a hire or not, it relies on a whole lot of different factors. My biggest challenge is that I have lots to do but very little time to complete it. There are not enough hours in the day. Another challenge is that I may have too many positions to work on. Finally, being able to find the right skill set to fill tech roles can prove to be a big obstacle. Internally it is a group decision because there needs to be a consensus among the group. On the client side, they ultimately make the decision, so we try to help work them through the process and guide them through who we feel are the best candidates. Ultimately the company is going to make a decision based on the candidates we present, so it is really important that we present the right ones to

Talent Management Strategy Research Paper Example | Topics and Well Written Essays - 1500 words

Talent Management Strategy - Research Paper Example The current employment size of the organisation in over 20,000 people worldwide and the company is continuing to expand into newer markets. The company has come a long way from its humble origins in the early forties when it was founded in a small state in Europe. Currently Hilti operates in over 120 countries worldwide and tends to operate in one of the most competitive markets in the world (Hilti, 2009). In order to gain competitive advantage over its competitors Hilti has a continuous need for innovation that it tends to meet using talent management methods. The added pressures to make the workplace safer have meant that health and safety regulations have been changing around the world in the past few decades (Fung et al., 2010). In order to keep up with the challenge, Hilti has been employing a number of different talent management strategies that are discussed in detail below. 2. Talent Management Strategy Talent management has grown to encompass human resource management throug h the active anticipation of human resource requirements. These requirements are tabulated and plans are devised in order to meet the identified human resources needs (Carpenter, Bauer, & Erdogan, 2010). Generally businesses engaged in talent management transfer the grooming of employees from the human resources department to the line managers directly in order to produce more efficient strategies. It also tends to make more sense given that the line managers have far greater expertise in determining the needs and requirements of individual employees. These can be used to align the development of individuals with the developmental needs of the organization far more flexibly. The largest reason for the enhanced flexibility is the simplification of the overall framework that does not remove the human resources department but instead tends to simplify the process flow. Typically talent management programs can pursue either of two preferred paths in order to enhance the overall human re source potential. The simpler strategy is to hire talented individuals from the labor market and to manage them accordingly. Another alternative strategy is based on the assumption that all individuals carry some form of talent. This strategy relies on grooming the individual talents of all employees in order to garner human resources. Therefore, talent management in an organization could be diverted at a select few individuals or to the entire labor set in order to develop human resources to empower the organizational objectives and goals (Rammer et al., 2010) (Perdomo-Ortiz et al., 2009). While some organizations have chosen to pursue the former path over the latter but Hilti has chosen to use the latter path. The development of a few select individuals tends to lower the costs for talent management but exposes the business to greater risks. These risks arise when the talented and groomed individuals choose to leave the organization for any number of reasons. Above anything else, this could occur due to the â€Å"war for talent† (Michaels, Handfield-Jones, & Axelrod, 2001) where an organization decides to capture the available talent pool from the market by providing better pays and perks. The human resources that leave an organization in this scenario represent a large

Childhood Memories Image Essay Example | Topics and Well Written Essays - 500 words

Childhood Memories Image - Essay Example In this picture, two children topless are playing on the river where they are joined by two water buffalo and its calf. Behind the buffalos, there is an old man with gray hair whom may be was with the children before the buffalo entered. Perhaps the children and the old man were cleaning themselves and washing the buffalos maybe after long hours working in the field as according to Viet Nam  culture. Water buffalo help peasant farmers lessen the burden of farm work as well as their significant property. The buffalo, one big and the other small maybe its calf splashes water to a great length along the river clearly showing they have just joined the children. The drops of water cover the background of the picture and almost obscure the older man’s face. One child seems to be touching the big buffalo with his left hand while the other enjoying as depicted by facial expression. The old man behind the cows is maybe waiving or raising his left hand a coincidence with the child tou ching the cow with the left hand. This picture was taken in the river or water pond. There seems good relationship between the two animals and the children. This leads to speculation that the animals belong to the children’s family as well as the old man who may be their grandfather. The presence of the boys and the buffalo in the river depicts different cultures in the world. Although people inherit various cultures, they have been interacting with different animals both kept domestically or esthetic. The Vietnamese people and the Asian have been domesticating water buffalo for both economic and aesthetic purposes. They form part of their agricultural civilization as well as cultural values. In fact, the boys, taking â€Å"shower† with the buffalos along the river with a grown-up man looking at the happening depict complete social, cultural inheritance.

Classification According To Maturity Biology Essay

Classification According To Maturity Biology Essay INTRODUCTION The human eye is very nearly spherical, with a diameter of approximately 24 mm (nearly one inch). It consists of three concentric layers, each with its own characteristic appearance, structure and functions. From outermost to innermost, the three layers are the sclera, which protects the eyeball; the choroid, which nourishes the eyeball; and the retina, which detects light and initiates neural messages bound for the brain. The eye is partitioned into two chambers, a small anterior chamber and a larger vitreous chamber. Thus the basic layout consists of three concentric layers, two chambers, iris, pupil and the lens (Ross and wilson, 2001). Fig.1 Anatomy of the eye C:UsersDHINESHDesktopUntitled1.png The Lens One of very important optical element of the eye, the crystalline lens, lies right behind the iris. The lens takes its name from its resemblance to a lentil, or bean. In adults, the lens is shaped about 9 mm in diameter and 4 mm in thickness. The lens consists of three distinct parts: an elastic covering, or capsule; an epithelial layer just inside the capsule; and the lens itself. The thin, elastic capsule around the lens has two jobs. First, it moderates the flow of aqueous humor into the lens, helping the lens retain its transparency to light. Second, the elastic capsule moulds the shape of the lens varying its flatness and, thereby, the lens optical power. This variant in optical power is called accommodation. Lens grows throughout the life span; the outer, epithelial layer of lens continues to produce protein fibres that are added to the surface of the lens. Consequently, those protein fibres nearest the centre of the lens are the oldest (some were present at birth), whereas the fibres on the outside are the youngest. Between birth and 90 years of age, the lens quadruples in thickness and attains a weight of 250 mg. In the centre of the lens, the old fibres become more densely packed, producing sclerosis, or hardening, of the lens (Paterson, 1979). For good vision, the lens must be transparent and light must be able to pass through it easily, without loss or deviation. Like the cornea, this transparency depends on the material out of which the lens is made. Of all the bodys parts, the lens has the highest percentage of protein, and its protein fibres are lined up parallel to one another, maximizing the lens transparency to light. Anything that disturbs this alignment such as excess fluid inside the lens reduces its transparency. An opacity (or reduced transparency) of the lens is called a cataract. While some cataracts are minor, barely reducing the transmission of light, others undermine vision to the extent of blindness (Kyselova, 2004). Cataract Cataract is the opacification and crystalline formation of eye lens, associated with the breakdown of the eye lens micro-architecture, which interferes with the transmission of light onto the retina. Several biochemical processes for example, calcium deposition, oxidative stress, phase transition, altered epithelial metabolism, crystalline precipitation, calpain-induced proteolysis and cytoskeletal loss takes place during the development of cataract (Moghaddam, 2005). Fig.2 Normal, clear lens Fig.3 Lens clouded by cataract C:UsersDHINESHDesktopUntitled.png Fig.4 Etiology of cataract (Jacob, 1999) C:UsersDHINESHDesktopUntitled.png TYPES OF CATARACT A. Acquired cataract 1. Age related cataract a) Morphological classification i) Subcapsular cataract Anterior subcapsular cataract mainly associated with fibrous metaplasia of the epithelium present below the lens capsule. Posterior subcapsular cataract lies just in front of the posterior capsule and a clear vacuolated, granular or plaque-like appearance. Near vision is also most often impaired more than distant vision. ii) Nuclear cataract usually begins as an amplification of the changes most often seen with normal aging lens nucleus. It is often related with increased spherical aberration and also with an increased refractive index leading to myopia. Some elderly patients may consequently be capable to read yet again without spectacles. iii) Cortical cataract may be associated with the anterior, posterior or equatorial cortex. The opacities begin as clefts and vacuoles between lens fibres because of hydration of the cortex. Both cortical and subcapsular cataracts are white on oblique illumination and show black colouration, silhouetted against the red reflex, on retroillumination. b) Classification according to maturity i) An immature cataract means partially opaque lens. ii) A mature cataract means completely opaque lens. iii) A hypermature cataract means the leakage of water from the lens it leads to wrinkled and shrunken anterior capsule. iv) A morgagnian cataract means the total liquefication of lens cortex like hypermature cataract and it allows the lens nucleus to shrink inferiorly (Hejtmancik, 2004). 2. Presenile cataract Cataract may develop early in the following conditions, a) Diabetes mellitus Typically diabetic cataract is rare. In hyperglycemic conditions, the aqueous humor secretes high level of glucose and this excess of glucose diffuses into the lens. Aldosereductase metabolises glucose to sorbitol, which then accumulates in the lens, resulting in secondary osmotic over hydration of the lens substance. Nuclear opacities are common and tend to grow rapidly. Premature dystrophy may be seen due to decreased pliability of the lens. b) Myotonic dystrophy About 90% of patients, in third decade have fine cortical iridescent opacities, which evolve into visually disabling stellate posterior subcapsular cataract by the fifth decade. c) Atopic dertmatitis About 10% of patients with severe atopic dermatitis develop cataracts in the second to fourth decades. The opacities are often bilateral and may mature quickly. Shield like anterior subcapsular plaque which wrinkles the anterior capsule is characteristic. Posterior subcapsular opacities resembling a complicated cataract may also occur. 3. Traumatic cataract Trauma is the major risk factor for unilateral cataract in individuals. The following risk factors are involved in traumatic cataract, a) Direct penetrating injury to the lens. b) Concussion may cause an imprinting of iris colour on the anterior lens capsule (Vossius ring) as flower shaped cortical opacities (rosette cataract). c) Electric shock and lightening are rare causes. d) Ionizing radiation. e) Infrared radiation- In glassblowers, the IR rays causes exfoliation of the lens capsule which results in thickening of the superficial portion of the capsule and it further splits the deeper layer and protrudes into the anterior chamber. B. Drug induced cataract a) Steroidal drugs may induce cataract. Initially the lens opacities formed in posterior subcapsular region spreads into the anterior region. The relation between dose, duration of administration and the cataract development is unclear. It is understood that children may be more at risk to the cataractogenic effects of systemic steroids and genetic susceptibility may also be of significance. Patients who develop lens physiological changes should have their dose decreased to a minimum, reliable with control of the underlying disease, and if feasible be considered for alternate drug therapy. Premature opacities may regress if therapy is discontinued, alternatively progression may occur despite withdrawn and warrant surgical intervention. b) Chlorpromazine may cause the deposit of innocuous fine, stellate, yellowish brown granules on the anterior lens capsule within the papillary area. The deposition of granular material may accumulate on the corneal endothelium and deep stroma. Both lenticular and corneal deposits are dose -related and irreversible. In very high doses (>2400 mg daily), this drug may cause retinotoxicity. c) Lens opacities may occur due to the irregular use of Busulphan (Myleran) for the treatment of chronic myeloid leukaemia. d) Amiodarone, used in the treatment of cardiac arrhythmias, causes visually inconsequential anterior subcapsular lens deposits in about 50% of patients on moderate to high doses. e) Gold used in the treatment of rheumatoid arthritis, causes harmless anterior capsular deposits in about 50% of patients on treatment for more than 3 years. f) Allopurinol, used in the treatment of hyperuricaemia and chronic gout, increases the risk of cataract formation in elderly patients, if the cumulative does exceeds 400 g or duration of administration exceeds 3 years. C. Secondary cataract A secondary (complicated) cataract grows as a result of some other primary ocular diseases. i. Chronic anterior uveitis is the main cause of secondary cataract. The earliest finding is a polychromatic lustre at the posterior pole of the lens which may not progress if the uveitis is arrested. If the inflammation persists, posterior and anterior opacities developed may progress to maturity. ii. Acute congestive angle closure glaucoma may cause small grey white anterior, subcapsular or capsular opacities within the papillary area. a. Myopia (Pathological) is linked with posterior subcapsular lens opacities and early-onset nuclear sclerosis, which may ironically increase the myopic refractive error. Simple myopia, however, is not associated with such cataract formation. b. Hereditary dystrophies such as retinitis pigmentosa, gyrate atrophy, leper congenital amaurosis and stickler syndrome may be associated with posterior subcapsular lens opacities. Cataract surgery may occasionally improve visual acuity even in the presence of severe retinal changes (Kanski et al., 2003). Free radicals involved in cataractogenesis Free radicals may be formed either by the reduction of molecules by electron transfer or by the haemolytic cleavage of covalent bond. Both these reactions may be enzymatic or non-enzymatic. Due to the presence of an odd unpaired electron in its outermost orbital, these free radicals are unstable and readily react with neighbourhood molecules and extract electrons from them, converting the attacked molecule into a few radical, which in turn attacks another molecule generating more free radicals and so on. This enables free radicals to induce chain reactions that may be thousands of events long. A free radical reaction is terminated by reaction between two free radicals or neutralization by antioxidants (Uday et al., 1999). Fig.5 Pathways of ROS formation C:UsersDHINESHDesktopUntitled 3.png Generation of free radicals Biological free radicals include reactive oxygen species, reactive nitrogen species, reactive sulphur species, free radicals obtained form xenobiotics. a) Superoxide anion radical (O2.-) It is generated from NADPH oxidase and from mitochondria. i) NADPH oxidase is present in the lysosomal cell membranes. It steals electron from O2 resulting in the formation superoxide anion radical (O ·2-). It is converted to hydrogen peroxide and is a spontaneous reaction which is known as respiratory burst. This hydrogen peroxide may react with the chlorine in the presence of myeloperoxidase to form hypochlorous acid or it may produce hydroxyl radicals, by the Fenton reaction which uses the metal ion Fe3+. ii) From Mitochondria: Ubiquionone, which is a terminal acceptor of electron, is converted to semiquinone (free radical). By reacting with O2, it forms (O ·2-) super oxide radical with H2O2, it produce hydroxyl radical ion. b) Hydrogen Peroxide H2O2 SOD It is formed by the dismutation of superoxide by the enzyme superoxide dismutase. O · 2 + O ·2 Hydrogen peroxide is generated from i) Aminoacid oxidases: Flavin is a co-enzyme required for the oxidative deamination of amino acid. The reduced flavin attacks molecular oxygen to form hydrogen peroxide. ii) Xanthine oxidase: Xanthine oxidase catalyses the conversion of hypoxanthine to xanthine and hydrogen peroxide is released from molecular oxygen. iii) Peroxisomes: Peroxisomes is the site of  Ã‚ ¢-oxidation of fatty acids.  Ã‚ ¢- Oxidation of the fatty acids is catalysed by acetyl co-enzyme-A dehydrogenase. During this process, a co-enzyme called FAD which donates two electrons gets reduced to FADH2. Again it is converted to FAD. During that process it gives out O2 and H2O (Kovaceva et al., 2007). c) Hydroperoxyl radical They are highly lipophillic and capable of initiating lipid peroxidation. Lipid peroxidation Lipid peroxidation is a self- perpetuating common process and involves the conversion of lipid components from cell organelles into lipid peroxides resulting in the formation of a pigment known as lipofuscin. Lysosomic reactive oxygen species are formed as a result of complex oxidative chain reactions in mitochondria during energy production. H2O2 formed in smaller amounts by mitochondria pass through walls of lysosome and react with Fe (II) in a reaction known as Fenton reaction to form potent hydroxyl radicals which cause lipid peroxidation (Halliwell, 2001). Malondialdehyde is the major reactive aldehyde resulting from the peroxidation of biological membrane polyunsaturated fatty acids (PUFA). MDA, a secondary product of LPO, is used as an indicator of tissue damage by a series of chain reactions. MDA is a by-product of prostaglandin biosynthesis. It reacts with thiobarbituric acid and produces a red-coloured product. MDA is a mutagenic and genotoxic agent that may contribute to d evelopment of human cancer. Ca2+ ATPase The Ca2+ ATPase is a transport protein in the cells that serves to eliminate calcium (Ca2+) from the cell. It is essential for maintaining the amount of Ca2+ within the cells. Based upon the electrochemical gradient calcium ion enter into the cells through the trans membrane. This process is important for the cell signalling by which it lowers calcium level. Thus it is necessary for the cell to utilize ion pumps to remove the Ca2+. The Ca2+ ATPase is expressed in a variety of tissues, together with the brain (Hightower et al., 1982). IN VIVO MODELS IN CATARACT (Gupta, 2004) 1. Sugar cataract i) Galactose induced cataract The changes associated with galactose cataractogenesis include the initial reduction of galactose into dulcitol through intervention of aldose reductase with NADPH as a co-factor. Accumulation of dulcitol in the lens, (since it is not metabolized) creates cellular hypertonicity associated with and/or followed by a cascade of events, which includes an influx of water, swelling of the lens fibres, epithelial cell edema, damage of plasma membrane, compromise of cellular permeability, a drop in myinositol level, a reduction in Na+ K+ ATPase activity an influx of Na+ and Cl- and an efflux of K+ and the loss of glutathione and aminoacids. These are the morphological, biochemical, enzymatic and molecular alterations in the lens associated with galactose cataracts. ii) Alloxan induced cataract Alloxan is a cyclic urea analog which is highly reactive molecule that is readily reduced to dialuric acid, which is then auto oxidized back to alloxan resulting in the formation of hydroxyl radical, O2.-, including H2O2 (hydrogen peroxide). However, the other mechanism reveals the ability of alloxan to react with protein sulfhydryl groups on hexokinase, a signal recognition enzyme in the pancreatic ÃŽ ²-cells that couples changes in the blood glucose concentration to the rate of insulin secretion. By this mechanism, inhibition of glucokinase and other SH containing membrane proteins on the ÃŽ ²-cells would eventually result in cell necrosis within minutes. iii) Streptozocin induced cataract Diabetes related cataractogenic changes are seen in the animals injected with streptozocin. This streptozocin initiates cytotoxic action in pancreatic ÃŽ ² cells because sreptozocin contain glucose molecule and highly reactive nitrosourea side chain. It binds to the membrane receptor to generate structural damage. At the intracellular level three major phenomena are responsible for ÃŽ ² cell death, i) Methylation ii) Free radical production iii) Formation of Nitric oxide (NO). The damage caused to ÃŽ ² cells alters the sugar metabolism leading to diabetes. 2. Selenite induced cataract Selenite cataract resembles human cataract in many ways such as insoluble protein, vesicle formation, increased calcium, reduced glutathione (GSH) and decreased water-soluble proteins. However, selenite cataract shows no high molecular weight protein aggregation or increased disulfide formation and is dominated by rapid calpain-induced proteolytic precipitation, while senile cataracts may be produced by prolonged oxidative stress. 3. Naphthalene induced cataract Naphthalene is oxidized in the liver initially to an epoxide and then it converted into naphthalene dihydrodiol. This stable component is converted enzymatically into dihydroxynaphthalene to reaching the eye. Being unstable at physiological pH, 1, 2- dihydroxynaphthalene and spontaneously autooxidises to 1, 2- naphthoquinone and H2O2 . It alkylates proteins, glutathione and aminoacids and generates free radicals. 4. Glucocorticoid induced cataract Glucocorticoid cataract results in the formation of steroid- adduct protein, induction of transglutaminase and reduction of ATPase activity may lead to cataract. Steroid cataracts are produced by the activities of glucocorthicoids and progressed by way of production of oxidative stress similar to other types of cataract. 5. L- Buthionine S, R- Sulfoximine (BSO) induced cataract Glutathione is present in mammalian lens in high concentrations and is involved in the protection of lens against oxidation. In most of the cataracts the decrease in its level is observed. 6. Smoke induced cataract Cigarette smoke contains trace and heavy metals. The increased metal contents in lens cause lens damage by the mechanism of oxidative stress-forming oxygen radicals, via metal catalyzed Fenton Reaction. In other words cigarette smoke is associated with the accumulation of iron and calcium. 7. UV radiation induced cataract Epidemiological studies have exposed a link between exposure to UV radiation in sunlight and development of cataract. Experimental studies confirm that ultraviolet (UV) radiation induces cataract. There is, however, a lack of data on the age dependence in experimental UV radiation-induced cataract. 8. Microwave induced cataract Microwave radiation has been reported to produce posterior subcapsular and cortical cataracts in rabbits and dogs within a short span of time. 9. Transforming Growth Factor ÃŽ ² (TNFB) induced cataract TGFB is induced by injecting approximately 60 ng TGFB into the vitreous. TGFB induce lens epithelial cells to undergo molecular modify and abnormal morphologic that mimic the changes observed in human posterior subcapsular and cortical cataract (Gupta, 2004). IN VITRO MODELS IN CATARACT (Gupta, 2004) Induction of cataract in isolated animal lenses maintained in organ culture has become a convenient, quick and appropriate method for testing the anticataract efficacy of an agent. Opacification of lens is induced by generating oxidative stress/ hyperglycemic/ hypergalactosemic conditions around the lens by supplementing the culture medium with a variety of exogenous substances. 1. Oxidative stress induced cataract Oxidative mechanisms play an important role in many biological phenomena including cataract formation. Formation of the superoxide radical in the aqueous humor, lens and its derivatization to other potent oxidants may be responsible for initiating various toxic biochemical reactions leading to the progress of cataract. In vitro such cataracts are induced by agents like selenium, H2O2, photosensitizers and enzyme xanthine oxidase. 2. Selenite induced cataract In vitro cataract is produced by supplementing the tissue culture medium with 25 to 100 mM sodium selenite in which freshly enucleated transparent rat lenses are incubated at 370C. This causes membrane damage and faint cortical opacities within 24 h. 3. Photochemically induced cataract Riboflavin, a photosensitizer, is supplemented in the culture medium to induce cataract in cultured lenses. Micro quantities (4-200  Ã‚ ­M) of riboflavin lead to severe physiological damage and opacification within 24 h after exposure to light. The initial membrane damage is evidenced by a disturbed cation ratio between lens water and the medium of incubation. Riboflavin on getting photosensitized generates free radicals in a sequence of reactions. Lenses are maintained in organ culture for 24 to 72 h. The lenses are divided into four groups and incubated in the dark and light both in presence and absence of riboflavin. The lenses are exposed to light with two 15-w daylight fluorescent lamp placed at 8 inches above the cluster plate. The culture medium is replaced every 24 h. Riboflavin shows no effect on the lens in the absence of light, and light without riboflavin has no significant effect. opacification starts in the equatorial zone and gradually extends towards the centre of the lens. 4. Enzymatically induced cataract Supplementation of culture medium with 1 mM xanthine and 0.1 unit xanthine oxidase, which act as substrate and enzyme respectively, leads to generation of superoxide radical. The lenses suffer severe oxidative damage and turn opaque within 24 h when incubated in culture medium at 370C. 5. Hydrogen peroxide induced cataract Incubation of lenses in medium containing 50-500  Ã‚ ­M H2O2 and it produce cataract. Opacification starts in the equatorial region within 24 h. The entire superficial cortex becomes opaque by 96 h. Due to the high instability of H2O2, the medium is changed every 2 h during the first eight hours. 6. Sugar induced cataract Transparent and undamaged lenses are incubated in a basis culture medium with fetal calf serum for 24 to 48 h. In the control group the medium is supplemented with glucose (30 mM), lenses develop opacity in the subcapsular region on day 1 and in the central region on day 2. Biochemical analyses reveal raised polyol, malondialdehyde levels and water content, and decreased glutathione levels in these lenses. 7. Steroid induced cataract Steroid-induced experimental cataract is produced in vitro by incubating the transparent lenses in the medium containing methyl prednisolone (1.5 mg/ml). The test agent and methyl prednisolone added alone and together to the medium form drug control, control and treated groups respectively. Early cataract around the equator is produced within 24 h of incubation. Incubation period may be extended to 48 h for dense opacity. Morphological changes and modulation in biochemical parameters between the groups may show the potential of the anticataract agent. 8. Naphthalene induced cataract TC-199 medium is used for the preincubation of lens. Stock solution of napthalene dihydrodiol is prepared in 20% ethanol at 2.5-10-3 M concentration. The stock solution is diluted 1:100 to obtain the final concentration of 25.5 -10-5 M. The final osmolarity of the solution is 295-300 m Osmol. Rat lenses are incubated in TC-199 medium containing napthalene metabolite solution. Medium is renewed daily till 72 h. Lenses remain clear during the initial 24 h but from shell-like opacity around the nucleus by 48 h. Opacification becomes more peripheral and widespread after 72 h. At 48 h, under such conditions of incubation, development of opacity mimics the in vivo napthalene cataract. Naphthalene is oxidized in the liver first to an epoxide and then is altered into naphthalene dihydrodiol. This stable component on reaching the eye gets converted enzymatically to dihydroxynaphthalene. Being unstable at physiological pH, 1,2 dihydroxynapthalene sponaneously auto oxidises to 1,2 naphthoquinon e and H2O2. It alkylates proteins glutathione and amino acids and generates free radicals. There is a loss of protein thiol in this reaction and the products are less easily digestible by pancreatin than normal lens protein (Rees and Pirie, 1967). 9. Ca2+ induced cataract In this model, the control group contains the lenses incubated in the medium enriched with 20 mM Ca2+ or 1x 10-2 mM A23187 calcium ionopore. The treatment group lenses are cultured in the calcium and the test drug-containing medium. Incubation period can range from 24-72 h (Gupta, 2004). Fig.6 Mechanism of action of glucose-induced cataract C:UsersDHINESHDesktopUntitled 7.png Under physiological conditions, glucose is metabolized through the glycolytic pathway. An excess amount of glucose is converted to sorbitol by enzyme aldose reductase via polyol pathway. The glucose conversion into sorbitol by utilizing NADPH results in the reduction of NADPH/NADP+. Moreover, sorbitol undergoes oxidation to fructose by using sorbitol dehydrogenase (SD). Sorbitol does not easily cross cell membrane. Intra lenticular accumulation of sorbitol, leads to lens damage (Kyselova, 2004). Fig.7 Biomorphological changes during cataract formation C:UsersDHINESHDesktopUntitled 66.png As, the lens starts to swell in response to the hyper osmotic effects of polyol accumulation, membrane permeability changes resulting in an increase in lenticular sodium and decrease in the levels of lenticular potassium, reduced glutathione, ATP and free amino acids. The overall antioxidant status of the lens decreases because of depletion of GSH (Kyselova, 2004). Mechanism of action of calcium-induced cataract Fig.8 Calcium transport pathway Increased levels of lenticular calcium activate calcium dependent proteases. The activated proteases hydrolyze cytoskeletal proteins and lens crystalline. Crystalline cleavage would result from lower molecular weight peptides that could, in turn, aggregate to form higher molecular weight proteins (Wang et al., 1996). Various methods for the prevention of cataract The development of newer drugs for treatment of cataract mainly aims, interacting at the level of changed lens metabolism and lens pathophysiology. The in vitro, in vivo studies are used to identify the anti cataract agents. This epidemiological studies may be widely classified in the following categories (Gupta et al., 1997). Aldose reductase inhibitors Agents acting on glutathione Nonsteroidal anti -inflammatory drugs Vitamins, minerals and antioxidants Miscellaneous agents. 1) Aldose Reductase Inhibitors These drugs are aimed to prevent the metabolic dysfunctions of diabeties by polyol pathways. Aldose reductase inhibitors prevents the accumulation of sorbital within the lens would have an osmotic effect bringing in water and causing swelling and opacification. Sorbinil a spirohydantoin became the most powerful sorbitol lowering agent. Sorbinil prevents increased fluorescence and protein aggregation and it also acts as an antioxidant. 2) Non Steroidal Anti inflammatory Drugs The NSAIDS broadly studied are paracetamol, aspirin, Ibuprofen, sulindac, naproxen, and bendazec. The NSAIDS provide adequate productive effect to lens protein through various steps like acylation, carbamylation and inhibition of glycocylation. Some of them are also reported to inhibit lens AR to varying extent. NSAIDS contains antioxidant properties also. Most of the studies on the evaluation of anticataract potential of drugs have been conducted by feeding the drugs by oral route. 3) Agents which act on glutathione Glutathione is a tripeptide thiol known to control calcium inflex and protect lens protein from various agents like glucose and galactose. With advancing of age there is a considerable decrease in the concentration of glutathione and the decrease more prominent in lens with cataract. 4) Vitamins, minerals and antioxidants If oxidation in lens leads to cataract formation, then is feasible to prevent it by the use of antioxidants such as vitamins C and E and perhaps ÃŽ ²-carotene. The potential role of vitamins and antioxidants in preventing various diseases is well documented there are reports suggesting beneficial effect of vitamins like C and E in preventing cataract. Beta -carotene has also been demonstrated to protect lens damage by hematoporphysin. Ascorbate protects rubidium uptake against free radical damage and prevents light induced protein cross linking. Protective effect of vitamin C has been also reported in various in vitro studies. Vitamin E has been found to delay cataractogenesis in diabetic rats and in Emory mouse. Vitamins C and E,  Ã‚ ¢- Carotene and other anticataract agents probably act via a common mechanism of their scavenging properties of free radicals (Gupta et al., 1997b). Antioxidant enzymes 1) Superoxide Dismutase (SOD) SODs are a family of metalloenzymes that transfer superoxide in to hydrogen peroxide (H2O2) and represents the first line of defence against oxygen toxicity. 2O2- + 2H → H2O2 + O2 Three isoforms of SOD have been found. The first is mainly found in the cytoplasm of cells and it containing Cu and Zn at its active site (Cu/Zn SOD-1), the second containing Mn at its active site is located in mitochondria (Mn SOD-2) and the third (Cu/Zn SOD-3) is present in the extracellular fluid like plasma. SOD is a stress protein which is synthesized mostly in response to oxidative stress. It is found that little amount of Cu, Zn and Mn metals are crucial for maintaining the antioxidant activity of SOD (Halliwell, 1994; Ray and Husain, 2002). 2) Glutathione Peroxidase (GPx) GPx is one of the most important enzymes responsible for the degradation of organic peroxides and hydrogen peroxide in the brain. GPx catalyse the oxidation of GSH to GSSG at the expense of H2O2. There are two isoforms have been identified, selenium-dependent which is highly active towards H2O2 and organic hydroperoxides and selenium independent GPx. GPx activity has been reduced in selenium deficiency (Muller et al., 1984; Son et al., 2007). 3) Catalase (CAT) It is a heme-containing protein present in most cells. 2H2O2+ 2H2O → O2 Catalase is 104 times faster than GPx. It is having four protein subunits, each containing a heme Fe (III)-protoporphyrin group bound to its active site. GPx and CAT were found to be important in the inactivation of many environmental mutagens (Ray and Husain, 2002). 4) Glutathione (GSH) GSH has major intracellular antioxidant molecule and it is a tripeptide synthesised by enzymatic reaction involving two molecules of ATP from aminoacids like glutamate, glycine and cysteine. It plays a very crucial role in detoxification of peroxides and electrophilic toxins, mainly by acting as a substrate for GSH transferase and GSH peroxidase. It was shown that weakening of GSH enhances cerebral ischemic injury in rats (Mizui et al., 1992; Son et al., 2007).

McDonaldization Essay -- essays research papers

People At Work Coursework Question   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚   To what extent do you consider this concept of the McDonaldization of society disturbing, expected or inevitable, for employees in the twentifirst century. Also the possible consequences for theories of human motivation and whether the concept applies equally to all jobs. In this paper I will be analysing the effects McDonaldization has on society and the employees of the twentifirst century. I will be discussing whether McDonaldization is to be expected, accepted, rejected or is inevitable. I will also be arguing that McDonaldization does effect employee motivation, and how it fits in the numerous theories on motivation. McDonaldization as defined by George Ritzer is â€Å"the process by which the principles of the fast-food restaurant are coming to dominate more and more sectors of society†. This concept originally stems from the concept of bureaucracy, which was a type of organisational structure that aimed to rationalise and standardise its products and services and the processes it took to produce them. McDonaldization differs somewhat from bureaucracy as it concerns itself with its five main points: Efficiency, Calculatability, Predictability and Control. For the emphasis to be on these points it has an effect on employee’s jobs. Often it involves the de-skilling of the employees, under McDonaldization employees do not need a wide range of skills, In fact just to be productive they only need to know how to complete a single task. This has numerous benefits for the organisation, primarily it cuts down on training costs as it does not cost much to train for low skilled jobs, and as these jobs are so low skilled employees can be paid minimum wage. It also leaves employees with little bargaining power as staff can be replaced so easily. Jobs often become standardised and continually repetitive and leave room for little or free thinking or initiative to be employed. Staff are often replaced or governed by technological changes. However it is argued that the effects McDonaldization has on employees depends on the many variables surrounding your job i.e. public or private, Blue collar (professional) or white collar (menial) jobs or simply the type of industry retail, service or tertiary. Public sector jobs tend to be as less affected by McDonaldization than pr... ...n, Supervision, Working Conditions, Relationships, Salary, Status and Security. As I outlined in previous paragraphs that McDonaldization has a negative impact on all these things. Herzbergs model also names motivators as being achievement, recognition, interest in tasks, responsibility and advancement. McDonaldization by design makes it more difficult to make big achievements and even harder to be recognised for them. With the standardisation of many jobs interest in the tasks are unlikely to play a big part in motivation. Increased responsibility, growth and advancement have also been negatively effected by McDonaldization and opportunities for either of these motivators is become bleak. Overall one can see that the effects McDonaldization have had on society and its employees tend to be negative ones. But the reason it is so widespread is because huge organisations rely on it as a means to maximise profit. But is the price too high for the rest of us to bear. It plays as a de-motivator, effects our everyday thinking. References George Ritzer ‘The McDonaldization Of Society’ Abraham Maslow Fredrick Herzberg Dr Ellen Langer Mullins Buchanan & Huczynski

Essay --

Kashayla Snipes Dr. Nancy Blair English Composition 1102 February 25, 2014 Othello: A Tragedy of Jealosuy â€Å"Jealousy is troublesome to others, but a torment to themselves.† Those are words from a famous entrepreneur and philosopher, William Penn. In William Shakespeare’s Othello, the act of jealousy is a powerful sensation seen almost in every aspect and relationship throughout the tragedy. Furthermore, it is one of the most important topics in the play. Based on the conflicts within Othello, jealousy can be defined as troubles or misfortune caused by hallucinations. At the same time, Millicent Bell states in his essay, â€Å"Othello’s Jealousy† that the characters are driven to madness by being allowed to see what really is not so or simply using imagination. Bell also goes on to say the jealousy traits are shown only in a sexual manner. That statement can be argued against. True enough, sexual jealousy is shown in Othello, but it is not the only form of jealousy exposed. According to Medical Dictionary, sexual jealousy is a condition characterized by suspicion of a spouse's infideli...