Clostridium tetani Essay Example | Topics and Well Written Essays - 1250 words

Clostridium tetani - Essay Example The author has rightly presented that Clostridium tetani is obligate anaerobe and doesn’t grow in the presence of oxygen. Optimal conditions for growing this bacterium are temperature of 37 degrees Celsius, with PH of 7.4. It grows on different nutrient media including agar enriched with blood. When cultivated on agar enriched with blood it manifests alpha hemolisis, but with prolonged cultivation it produces beta hemolisis. Because Clostridium tetani is mobile bacteria and has flagella when cultivated produces the effect of swarming and tends to spread over the complete area of the culture. When cultivated produces very thin and see-through layer of bacteria that is very hard to notice with a naked eye, except on the edges of the colonies. It is difficult to obtain a pure culture of Clostridium tetani, this is why method called Fildes technique is often used, when the bacteria is inoculated on a small area on an agar plate and after incubation of 10 hours another subcultures are made from the edge of the swarming area that is constituted mostly of Clostridium Tetani. In suboptimal conditions, Clostridium tetani forms spores that are relatively resistant. Spores are killed in boiling water for 10-15 minutes, and in the moist heat of 121 degrees Celsius after 20 minutes. Based on the agglutination process Clostridium Tetani is classified in 10 serological types (only type IV doesn’t have flagella and is not mobile).... It is protein based molecule with molecular weight of 150 kDa (Kilo Daltons) and is constitutes of two parts, heavier or B chain with weight of approximately 100 kDa and lighter A chain with molecular weight of 50 kDa. Heavier B chain of this toxin bonds to the cell membrane and helps chain A to enter the cytosol of the cell (Farrar et al. 2000). The A chain than migrates through the axons to the central nervous system. Lighter A chain of the tetanospazmin toxin in the CNS impairs the release of inhibitory neurotransmitters in the brain (GABA-gamma aminobuteric acid and glycine) by degrading protein called synaptobrevin (small membrane based protein). Consequence of this effect is hyperactivity of the skeletal muscles in the body and development of muscle contractions and muscle spasm (Schiavo et al. 1992). Infection with C Tetani may cause development of condition called tetanus. It is disease that is characterized by presence of generalized spasms of the skeletal muscles in the bod y that is produced by the tetanospasmin toxin. It is caused when a wound is contaminated with spores of Clostridium Tetani. C Tetani are widespread bacteria that are present in the soil, dust, manure of domestic animals, our clothing and in about 20 percents of human gastrointestinal tract (Bleck 1995). If the wound is deep enough spores of C. tetani in anaerobic conditions can develop in viable bacteria that start to release toxins. Toxins are released when the bacteria are destroyed and bacterial cytosol along with toxins is released into the human tissues. Incubation period between the infection and occurrence of first symptoms ranges between 3 and 21 days, but that depends mostly on the site of primary infection. As early sign patients may report dysphagia and sore throat and some

FINANCIAL MARKET AND PRODUCT RISK Essay Example | Topics and Well Written Essays - 1000 words

FINANCIAL MARKET AND PRODUCT RISK - Essay Example The two of the stylized financial asset pricing model is Capital Asset Pricing Model (CAPM) and Arbitrage Pricing theory (APT). The paper will be focusing on the critical evaluation of these two asset pricing models and will be analyzing the justification of its use with that of a fund manager in the United Kingdom. Let us begin our discussion with the notion of these two models before plunging into their critical evaluation. Mechanics of CAPM The capital asset pricing model (CAPM) developed by Sharp (1964), Linter (1965) and Mossin (1966) (Zhang & Wihlborg, 2004, p.1) assumes that stock returns are usually evolved from one factor model which represents the market portfolio of all the risky assets. The theory is structured on the notion that it is an aggregation of the Portfolio theory and some additional ones. In the CAPM model, the concept of risk free asset resulted in the derivation of Capital Market Line which is referred to as the new efficient frontier. The equation for the CA PM model can be stated as follows: is the required rate of return on a risky asset and it is a function of risk free rate and risk premium . The market risk premium is the difference between the return on the market and the risk free return. is crucial as it determines the sensitivity of the stock market to that of the market which shows by what amount the price of a stock will fluctuate in specific fluctuations to that of the stock market (Zubairi et al, 2011, p.441). But the critical point in the estimation of the CAPM. The model assumes that the return on a stock is dependent on whether the price of the stock follows the prices in the market as a whole. It is useful as it represents a statistical representation of the past risk. Although there is no certainty but a high probability will be attached to infer the statement that the companies which strong stock price history will also performs in the future. The critical point in the estimation of the CAPM is the difficulty of measu ring the true market portfolio (Donovan, 2007, p.3). The APT theory is a modified version of CAPM which is discussed in the following segment. Mechanics of APT Developed by Ross (1976) APT states that a large number of sources for risk are present in the economy which cannot be eliminated by the process of diversification (Iqbal & Haider, 2005, p. 121). The risks are thought to be of the factors like inflation, output fluctuations, fiscal and monetary shocks. APT is modified than CAPM in the sense that it focuses on the measurement of a large number of Betas () than a single Beta which was calculated in CAPM model. The Betas are calculated by the estimation of the sensitivity of the return of the assets with respect to change in each factor. It possesses a linear relationship between the returns on risky assets and a small set of economy wide common factor. The equation is given as follows: Here, is the expected return of the ith stock. Fj represent the unobserved economic factors a nd bij represent the sensitivity of the security i to that of the economic factors j and ?I is the stochastic parameter known as the uncontrolled factor (Donovan, 2007, p.3). Now let us analyze which model a fund manager sitting in the UK will be adapting. Characteristics of the shares traded in the London Stock exchange The companies whose shares are traded in the London Stock Exchange vary largely where the smallest companies are valued