Computer Systems Essay Example | Topics and Well Written Essays - 3000 words

Computer Systems - Essay Example The Midrange virtualization includes Solaris containers and zones and the commodity virtualization consists of VM ware, Oracle VM and Xen. The desktop virtualization is categorized in two PC / MAC and Virtual desktop infrastructure (VDI). The category named as PC / MAC includes virtual box, virtual PC etc. VDI consists of Oracle VDI and desktop virtualization by Citrix. The next category is the storage virtualization, which includes storage area networks and arrays developed by Exadata, Netapps etc. Lastly, there is a category named as network visualization consisting of Virtual Local Area Networks (VLAN). A single piece of hardware is divided into multiple instance by a technology is known as virtualization. The OS (operating system) along with hardware is similar even before virtualization. The division of hardware makes the resource transmission simple as, an operating system (OS) needs to utilize all resources that are available in a box. A single box with the help of resources c an host several instances or nodes. For example RAM I/O capacity i.e. permanent storage space, central processing unit and bandwidth (network address). Likewise, this procedure facilitates an effective method for resource management of web application. For instance, a web application that is hosted on a relatively small node works on reduced cost of using entire box and still manages to provide resources from one node to another. In order to enhance the efficiency an unused resources in a box are moved. Optimal resource management is achieved by virtual server; we can also say that there is no requirement for deploying a web application and its components for migration of web services to some other hosts that are subjected to re-installation of new operating system. Consequently, virtualization fulfills the last process by utilizing a hypervisor. Likewise, the hypervisor hosts operating system that provides management of assets for many operating systems of visitors as well as nodes . Hence, as soon as a web application is deployed with virtualization technology, we can get a guest operating system powered by hypervisor. This is the major factor that provides scalability and assignment of more resources for the web application by clicking few buttons (Kusnetzky 2011). It is unnecessary to state that virtualization appeared in the year 1960 because a number of hypervisors are present to select from them. For the trendiest virtualization appliances are Xen and Virtual Box (Kusnetzky 2011). They are considered as open-source assignments due to their commercial popularity through corporations such as VMware and Nimbus data systems. However the process of virtualization is actually without responsibility. In fact, some disadvantages are also associated with its implementation. For example, â€Å"a hardware box's configuration is not clear to node users. A hardware box could be near its overall hardware limit, in which case more resources for a node could be limited , even requiring migration to another box†. In addition, it could appear as a weak virtualized resource for instance I/O capacity. In this situation various nodes are present in similar boxes try to interpret form the matching pair of hard drives thus resulting in amplified latency. Moreover, the sidebar contains more

Malcolm a Homemade Education Essay Example for Free

Malcolm a Homemade Education Essay Down syndrome is the most common cause of mental retardationDown syndrome is the most common cause of mental retardation. It is caused by the presence of an extra chromosome. Chromosomes contain sequences of DNA called genes that represent the genetic information that exists within a cell. Twenty-three distinctive pairs of chromosomes which is 46 in total. They are located within the nucleus (a region of the cell that is bounded by a specialized membrane, and which houses the genetic material). When a sperm cell fertilizes an egg cell, the newly created zygote normally receives 23 chromosomes from each parent. The contribution of genetic information from each parent is what makes each baby a distinctive blend of both characteristics. In Down syndrome a mistake during division of the sperm or egg cell produces a cell with an extra chromosome 21. This event occurs during cell division and is referred to as nondisjunction, or the failure of all chromosomes to separately properly resulting in retention of one of the chromosomes in one of the two new daughter cells. This is also called trisomy 21 and is accounted for 95% of all Down syndrome patients. A rare number of Down syndrome cases the original egg and sperm cells begins with the correct number of chromosomes but shortly after fertilization during the phase where cells are dividing rapidly a single cell can divide abnormally creating a line of cells with an extra chromosome 21. It’s called a cell line mosaicism. The individual with this type of down syndrome has two types of cells: some 46 chromosomes which is the normal number and some with 47. Individuals who are mosaic for trisomy 21 typically have less sever sign and symptoms of the disorder. Another are location that can cause down syndrome is called a chromosome translocation. This is an even that unlike the numerical abnormally causing trisomy 21, there is a structural abnormality. Exchange of material from two different chromosomes during the production of sex cells can take place such that there is a whole chromosome 21 attached to another chromosome but the chromosome number is normal. [1]These types of translocation involving chromosome 21, occur in about 3-4% of cases of Down syndrome. Ancient cultures, such as those in Greece, Rome, and Egypt, put disabled infants to death. Compassion toward the disabled was awakened by the early Christian church, but its charitable influence waned during the middle ages. Down syndrome also affected this people due to no one really caring about what was going on with the ill children. Down syndrome has a lot of causes and this is normally what some parents want to know is why their child is born with this syndrome. Most times this is why they tell you while you are carrying your child you need to watch very closely and look for all signs of genetic disorders with pregnant. Down syndrome is a chromosomal disorder as I said before. A baby is usually identified at birth through observation of a set of common physical characteristics. Babies with Down syndrome tend to be overly quiet. When I say that I mean less responsive with weak floppy muscles. With that being said a number of physical signs might be present. This includes a flat bridge of the nose which is smaller than normal. It’s a low set nose. They will tend to have a small mouth with a protruding tongue, upward slanting eyes and also extra folds of skin located at the corner of each eye, near the nose. They will have small outwardly rotated ears and small hands as well. Usually they have an unusual deep crease across the center of the palm and a malformed fifth finger. They will have a wide space between the big and the second toes and unusual creases on the soles of the feet. They also experience shorter than normal height later on in their childhood. Before genetic testing became available, Down syndrome was diagnosed based on certain typical physical characteristics. Not all people with Down syndrome have all these characteristics though. This can vary from certain people and are caused by the extra chromosomes. Individuals with Down syndrome also have joints that are looser than normal. Their skulls are short and broad. Newborns usually have extra skin on the back of their neck, and as the child gets older the neck often appears short and wider than usual. [2]Facial shape is round in the newborn and also during infancy. When the child gets older their face shape becomes oval like. This is due to the underdevelopment they go through. Their cheeks are round and the teeth develop late and in an unusual order. Although Down syndrome is not curable and there will be no cure for it, parents, researchers, and also the Down syndrome individuals try to make the best out of life and try dealing with it. Advances in medical treatment over the past 40 to 50 years for conditions such as heart defects and respiratory disease have led to dramatic increases in the life expectancy of those with Down syndrome. [3] Half of the children born with Down syndrome during the late 1960s survived to age 5. Bronchopneumonia, a respiratory illness and heart defects were the most common causes of death. Now about 80% of those born with it survive to age 10, and about 50% of them survive to age 50 or beyond. The recent statistics from various study places show that the place of incidence of Down syndrome anywhere from 1 in 600 to 1 in 1,000 live births. An analysis published by various people. Bray and colleagues in 1998 of combined data from nine different studies found that the incidence varies from 1 in 1,445 live birth mothers at age 10 to 1 in 25 live births to mothers at age 45. Down syndrome really is a hard disorder to live with but at the same time it has its advantages. Down syndrome has no treatment options but they have a lot of programs to help cope with this syndrome. The development of a child is a joyous thing. It involves amazing ohhs and ahhhs that would shock you every day your child does something new. All kids from the time their able to sit up by them and walks are learning new things everyday. Even as adults we learn new things everyday but still with Down syndrome, everything that they accomplish is outstanding. All kids learn to develop their fine motor skills but there are different aspects when it comes to Down syndrome children. The development of motor skills is very hard. The first thing you have to do is have a laid out foundation of how you plan on teaching that child. This is very dependent on stability. [4]Stability is being able to push open a heavy door. It’s being able to put on your shoes without falling. It is carrying a tray full of drinks. Its really a list that goes on but with this syndrome most things aren’t accomplished because down syndrome babies lack stability. Most of the people diagnosed wit this syndrome also tends to walk a little strange. They walk from side to side and always have their head twisted. Now as kids get older and reach their age past ten, then your not exactly ok, but you can breathe a little. Most researchers are still concerned about the older ones but its really the babies that most are worried about. They tend to go through a lot as newborns and unto there early infants stages. [5] Babies with Down syndrome suffer a lot. They have a lot they feel and go through, but being an infant and not being able to talk doesn’t help at all. Being born with Down syndrome you experience how it is from that point on and for the rest of your life. Children with this syndrome almost always have some degree of intellectual disability. That is why they learn slower and have difficulty with complex reasoning and judgment. The degree of intellectual impairment various tremendously. These kids do learn and what they do learn they will not forget. Down syndrome can not be prevented but it is People with Down syndrome, whatever their age, are people first. They are people with abilities, strengths and weaknesses like everyone else. They may have additional needs but first they have the same needs as everyone else of their age group. The quality of health care, education and community support provided to children and adults with Down syndrome makes a real difference to their progress throughout life. This module provides an introduction to all the issues that need to be addressed to enable individuals with Down syndrome, and their families, to enjoy full and happy lives within their communities. It offers an overview of the development of individuals with Down syndrome from infancy to adult life. It also provides a summary of the causes of Down syndrome, the incidence and prevalence of the condition, life expectancy and associated education and health care needs. Children with down syndrome experience problems with their digestive tract at a rate that is much higher than that of other children. [6] some of these problems such as blockage of the digestice tract can be life threatening and can require emergency surgery. Blockage or atresia of the esophagus or the duodenum can cause starvation if not corrected. Atresia occurs when the anal opening does not develop. This condition prevents solid waste from being eliminated from the intestinal tract and must be corrected surgically. Anal stenosis will allow waste products to pass, but will cause constipation. Gastroesophageal feflux is also more common in individuals with down syndrome. During this stage food reenters the esophagus from the stomach. This can cause vomiting and irritation of the esophagus. You can also have vision problem s with down syndrome to. Theses problems are common with those suffering with down syndrome. Strabismus in which one or both euyes either truns in or out. Occurs in 43% of theses chuldren. It is caused by abnormal or incomplete development of the cneters in the brain that control the coordination of eye movements. This condition may require an eye patch, special glasses or even surgery. Vision therapy may also be benificial and should be considered before surgery. Hearing problems also come with syndrome. [7] anatomical differences that result from trisomy 21 contribute to the larger percentage of hearing difficulties founf in individuals with down syndrome. Appromately 53% in children with down syndrome have hearing problems. This makes it more difficult to examine the ars for wax buildup and infection. The middle ear is smaller than normal, as well. This contributes to the presence of chronic ear infections in 40% to 60% of children with downs syndrome. The shallow nasal bridge founfd in 61% of individuals with down syndrome also contributed. Collapse or blockage of the eustachian tube, which leads from the ear to the throat, causes fluid to build up in the middle ear and increases the risk of middle ear infection. [8]In children with down syndrome the eustachian tubes are often smaller tha normal and have lowered muscle tone. Problems with fluid build up in the middle ear occur in 60% of indiviuals with down syndrome this fluid buildup interferes with hearing and can cause permanent hearing loss if it remains for a long peopif of time. Estimates of hearing loss in people with down syndrome range from 60% to 80%. Hearing loss in children can contribute to language and speech difficulies as well as auditory attention. Monitoring for fluid buildup and infections of the middle ear should begin before the age of six months and should continue into adulthood. Hearin aids may be a choice as well. Another problem that occurs in down syndrome individuals is problems with thyroid gland. Weighing less than one ounce the thyroid is actually one of the largest endocrine glands. Thyroid hormones help regualte the synthesis of growth factore and many hormones. Thyroid hormones are crucial for proper brain development during pregnancy. They are also important in normal growth. Because they are composed of the amino acid tyrosine, to which iodine molecules have been atattched adequate iodine in the diet is esstenial for their production. Another hormone produced by the thyroid gland is calcitonin which regulates the levels and metabolism of calcium. The hormones tri-iodothyonine and tetraiodothyonine are produced by the thyroid gland in a ratio of 1;14. t4 is secreted by the thyroid gland in responses to TSH. The active form, T3 is formed in the kidney, liver, and pleen by removal of one iodine molecule from T4. individuals with down syndrome also are 10 to 30 times more likely to develop Leukemia. [9] This is a type of cancer caused by the production of abnormal qhite blood cells by the bone marrow. These abnormal cells eventually crowd out normal white and red blood cells. There are two main types of leukemia. Acute and chronic. Acute leuk emias develop slowly and the patienst condition worsens slowly. Chronic leukemia develops rapidly and the patients syptoms worsen quickly. About 10% of babies born with down syndrome develop a transient leukemia that usually goes away by 3 months of age. About 20% to 30% of those with this transient condtion go on to develop acute leukemia. Babies who do not have down syndrome rarely have the transient form of leukemia. This higher risk of leukemia is in contrast to the risk of other types of cancer in individuals with down syndrome. The incidence of most types of solid tumors is muh smaller than in the general population. Down syndromes rates has also increased. From 1979 to 2003, the prevalence (total number of cases of a disease in a population at a specific time) of Down syndrome (DS) at birth increased by 31 percent, from 9 to 12 per 10,000 live births in 10 US regions. Within the 10 regions, birth prevalence of DS ranged from a low of 9. 7 in Arkansas to a high of 13. 7 in Utah during 1997-2003. The number of infants born with DS was almost 5 times higher among births to older mothers (38. 6 per 10,000) than among births to younger mothers (7. 8 per 10,000). In 2002, DS was found to be present in about 1 of every 1,000 children and adolescents aged 0 to 19 living in 10 chosen regions of the United States, which means that approximately 83,000 children and adolescents with DS were living in the United States during that year. Prevalence of DS by age group was the highest in 0-3 year olds at 11. , declining to 10. 3 among 4-7 year olds, 9. 8 among 8-11 year olds, 8. 3 among 12-15 year olds, and 6. 0 among 16-19 year olds. A screening test will help identify the possibility of Down syndrome. Screening tests do not provide conclusive answers, but rather, they provide an indication of the likelihood of the baby having Down syndrome. An abnormal test res ult does not mean that your baby has Down syndrome. The goal with a screening test is to estimate the risk of t baby having Down syndrome. If the screening test is positive and a risk for Down syndrome exists, further testing may be recommended. Diagnostic tests can identify Down syndrome before the baby is born. January issue of Obstetrics Gynecology, the American College of Obstetricians and Gynecologists released guidelines recommending screening for Down syndrome to all pregnant women during their first trimester. Agnostic tests tend to be more expensive and have a degree of risk; screening tests are quick and easy to do. However, screening tests have a greater chance of being wrong; there are â€Å"false-positive† (test indicates the baby has the condition when the baby really does not) and â€Å"false-negatives† (baby has the condition but the test indicates they do not). As far as those individual kids with Down syndrome there is a lot that they can do, just as the regular ones. Kids with Down syndrome tend to have a sense of humor. Those with this disorder have slurred words and stutter but what you can understand they have pretty good conversation. Also in about 4 percent of all down syndrome cases the individual possesses not an entire third copy of chromosome 21 material, which has been incorporated via a translocation into a no homologous chromosome. In translocation pieces are swapped between two non-related chromosomes forming hybrid chromosomes. The most common translocation associated with Down syndrome is that between the long arm (down gene area) of chromosome 21 and an end of chromosome 14. [10] The individual in whom the translocation has occurred shows no evidence of the aberration since the normal complement of genetic material is still present only a different chromosomes location. The difficulty arises when this individual forms gametes. A mother who possesses the 21/14 translocation, for example has one normal 21 one normal 14 and the hybrid chromosomes. She is a genetic carrier for the disorder because she can pass it on to her offspring even though she is clinically normal. The mother can produce three types of viable gametes: one containing the normal 14 and 21. the presence of an extra copy of the long arm of chromosome 21 causes defects in many tissues and organs. One major effect of Down syndrome is mental retardation. The intelligence quotients of affected individuals are typically in the range of 40-50. The IQ varies with age but being higher in childhood than in adolescence or adult life. The disorder is often accompanied by physical traits. Trisomy 21 is one of the most common chromosomal aberrations occurring in about 0. 5 percent of all conceptions and in one out of every seven hundred to eight hundred live births. About 15 percent of the patients institutionalized for mental deficiency suffer from Down syndrome. Before the chromosomal basis for the disorder was determined the frequency of Down syndrome births was correlated with increased maternal age. For mothers at age twenty the incidence of down syndrome is about 0. 5 percent which increases to 0. 9 percent by the age thirty-five and 3 percent at age forty-five. Comparing the chromosomes of the affected offspring with those of both parents have shown that the nondisjunction event is maternal about 75 percent the time. The maternal age effect is thought to result from the different manner in which the male and female gametes are produced. Gamete production in the male event in females. Formation of the femaleâ €™s gametes begins early in embryonic life, somewhere but between the eight and twentieth weeks. During this time, cells in the developing ovary divide rapidly by mitosis forming cells called primary oocytes. These cells then begin meiosis by pairing up the homologues. The process is interrupted now and the cells are held in a state of suspended animation until needed in reproduction, when they are triggered to complete their division. Most individuals with Down syndrome have intellectual disability in the mild (IQ 50–70) to moderate (IQ 35–50) range, with individuals having Mosaic Down syndrome typically 10–30 points higher. Dr. Weihs notes the mental qualities of people with Down syndrome to be unisexual, playful, affectionate, mischievous and imitative. [21]Language skills show a difference between understanding speech and expressing speech, and commonly individuals with Down syndrome have a speech delay. Fine motor skills are delayed and often lag behind gross motor skills and can interfere with cognitive development. Effects of the condition on the development of gross motor skills are quite variable. Some children will begin walking at around 2 years of age, while others will not walk until age 4. Physical therapy, and/or participation in a program of adapted physical education (APE), may promote enhanced development of gross motor skills in Down syndrome children. A 2002 literature review of elective abortion rates found that 91–93% of pregnancies in the United Kingdom and Europe with a diagnosis of Down syndrome were terminated. [54] Data from the National Down Syndrome Cytogenetic Register in the United Kingdom indicates that from 1989 to 2006 the proportion of women choosing to terminate a pregnancy following prenatal diagnosis of Down syndrome has remained constant at around 92%. In the United States a number of studies have examined the abortion rate of fetuses with Down syndrome. Three studies estimated the termination rates at 95%, 98%, and 87% respectively. Medical ethicist Ronald Green argues that parents have an obligation to avoid genetic harm to their offspring, and Claire Rayner, then a patron of the Downs Syndrome Association, defended testing and abortion saying The hard facts are that it is costly in terms of human effort, compassion, energy, and finite resources such as money, to care for individuals with handicaps People who are not yet parents should ask themselves if they have the right to inflict such burdens on others, however willing they are themselves to take their share of the burden in the beginning some physicians and ethicists are concerned about the ethical ramifications of the high abortion rate for this condition. [59] Conservative commentator George Will called it eugenics by abortion. 60] British peer Lord Rix stated that alas, the birth of a child with Downs syndrome is still considered by many to be an utter tragedy and that the ghost of the biologist Sir Francis Galton, who founded the eugenics movement in 1885, still stalks the corridors of many a hospital†. Doctor David Mortimer has argued in Ethics Medicine that Downs syndrome infants have long been disparaged by some doctors and government bean counters. Some members of the disability rights movement believe that public support for prenatal diagnosis and abortion based on disability contravenes the movements basic philosophy and goals. Peter Singer argued that neither hemophilia nor Downs syndrome is so crippling as to make life not worth living from the inner perspective of the person with the condition. To abort a fetus with one of these disabilities, intending to have another child who will not be disabled, is to treat fetuses as interchangeable or replaceable. If the mother has previously decided to have a certain number of children, say two, then what she is doing, in effect, is rejecting one potential child in favor of another. She could, in defence of her actions, say: the loss of life of the aborted fetus is outweighed by the gain of a better life for the normal child who will be conceived only if the disabled one dies. Individuals with Down syndrome have a higher risk for many conditions. The medical consequences of the extra genetic material in Down syndrome are highly variable and may affect the function of any organ system or bodily process. Some problems are present at birth, such as certain heart malformations. Others become apparent over time, such as pilepsy. Other things Down syndrome patients go through are very emotional. For people with Down syndrome it is very hard to cope with the everyday activities. It is also hard on the family, especially the parents. It can be very frustrating for the parents to cope with having a child with Down. People born with Down syndrome require so much more extra attention than that of a normal child. Suggestions from some psychologists are for the parents to go to some kind of group sessions to talk to other parents who have children with Down. Therefore, someone else can understand the frustrations that they go through in raising their child. People with Down syndrome have a lot of different emotions running through their mind and body. People with Down syndrome, whatever their age, are people first. They are people with abilities, strengths and weaknesses like everyone else. They may have additional needs but first they have the same needs as everyone else of their age group. The quality of health care, education and community support provided to children and adults with Down syndrome makes a real difference to their progress throughout life. This module provides an introduction to all the issues that need to be addressed to enable individuals with Down syndrome, and their families, to enjoy full and happy lives within their communities. It offers an overview of the development of individuals with Down syndrome from infancy to adult life. It also provides a summary of the causes of Down syndrome, the incidence and prevalence of the condition, life expectancy and associated education and health care needs. Further modules in this series address each of these issues in detail. Down syndrome patients also have another way to look at things. The most of the time feel different and out of place. Most would like to know who Down syndrome affects. For instance what race and what are the ratios of living past a teenager Children and adults with Down syndrome have a wide range of abilities. A person with Down syndrome may be very healthy or may have unusual and demanding medical and social problems at virtually every stage of life. It’s important to remember that every person with Down syndrome is a unique individual. Each child will develop at his or her own pace. It may take children with Down syndrome longer than other children to reach develop Down syndrome cannot be cured. However, early treatment can help many people with Down syndrome to live productive lives well into adulthood. Children with Down syndrome can often benefit from speech therapy, occupational therapy, and exercises to help improve their motor skills. They might also be helped by special education and attention at school. Some of the medical problems common in people with Down syndrome, like cataracts, hearing problems, thyroid problems, and seizure disorders, can be also treated or corrected. It has been suggested that children with Down syndrome might benefit from medical treatment that includes amino acid supplements and a drug known as Piracetam. Piracetam is a drug that some people believe may improve the ability of the brain to learn and understand. However, there have been no controlled clinical studies with Piracetam to date in the U. S. or elsewhere that show its safety and efficacy. The life expectancy for people with Down syndrome has increased substantially. In 1929, the average life span of a person with Down syndrome was nine years. Today, it is common for a person with Down syndrome to live to age 50 and beyond. In addition to living longer, people with Down syndrome are now living fuller, richer lives than ever before as family members and contributors to their community. Many people with Down syndrome form meaningful relationships and eventually marry. Now that people with Down syndrome are living longer, the needs of adults with Down syndrome are receiving greater attention. With assistance from family and caretakers, many adults with Down syndrome have developed the skills required to hold jobs and to live semi-independently mental milestones, but many of these milestones will eventually be met.

The Hydrolysis Of Nitrophenyl Phosphate

The Hydrolysis Of Nitrophenyl Phosphate The hydrolysis of nitrophenyl phosphate (NPP) by alkaline phosphatase enzyme is a first order reaction dependent on the concentration of NPP in solution. A product of this reaction is nitrophenyl anion which has a high molar absorptivity at 410nm. This property makes it relatively easy to observe this reaction as a function of time via a spectrophotometer. By observing the reaction as a function of time it is possible to study the kinetics of this reaction and to determine how the initial reaction rate depends on the initial concentration of NPP. This relationship can be described by the Michaelis-Menton equation which is described in some detail. It is found that, as expected, reaction rate increases with an increase in NPP concentration. The Eadie-Hofstee plot is used to linearize the data and to obtain reasonable approximations for the Vmax and KM parameters found in the Michaelis-Menton equation. A process involving the minimization of a ÃŽ §2 value is used to obtain the final va lues of these two parameters: Vmax = 4.28*10-7 and KM = 3.33*10-4. These parameters produce a qualitatively strong fit for the data obtained and so the Michaelis-Menton equation reasonably accurately describes the relation between initial NPP concentration and reaction rate. It is found, as expected, that the addition of the inhibitor species phosphate decreases the rate of NPA formation. The inhibition constant KI obtained from the apparent KM value of the Michaelis-Menton equation. By averaging the KI value for several concentrations of inhibitor, = (1.79 + 0.25)*10-4 M. Introduction Alkaline phosphatases are common enzymes found in places such as the mammalian intestine and the bacterium Escherichia coli. They are a family of two-subunit homologous enzymes which catalyze the hydrolysis of a large spectrum of phosphate monoesters to phosphate and neutral molecules. Because they catalyze a large variety of hydrolysis reactions, they are said to be non-specific. This reaction can be expressed as follows where R is any organic compound: R-OPO32- + H2O R-OH + HPO42- (1) By removing the phosphate, R becomes a neutral species that may more easily serve to facilitate transport of nutrients across cell membranes or other biological housekeeping processes. Alkaline phosphatases can also be used to remove phosphate groups from DNA molecules which allows for different manipulations of DNA. It is instructive to examine the kinetics of this reaction in order to more fully understand certain biochemical processes. Alkaline phosphatses are large molecules with a certain number of active sites in which the hydrolysis of smaller molecules is catalyzed. Competition for the active site of these enzymes is one aspect which may affect the kinetics of the reaction. We will examine the hydrolysis of p-nitrophenyl phosphate (NPP) by the E. coli alkaline phosphatase at a pH of 10.6 at room temperature. In particular, the maximum velocity Vmax and the Michaelis constant KM of the reaction are determined and the effect of the product HPO42- as an inhibitor is examined. Theory The initial rate, or the initial velocity, v of enzyme-catalyzed reactions has been observed to follow first order kinetics. That is, the rate of the reaction depends only on the initial substrate concentration. However, this only holds true at low values of substrate concentration and levels off to a maximum velocity V at large concentrations. The general form for the way in which an enzyme catalyzes a reaction is a noncovalent association of the substrate molecule to the enzyme followed by some catalytic steps that result in the product being released from the enzyme. S + E ES E + P (2) The enzyme concentration is almost always much smaller than the concentration of the substrate. Due to this, very quickly equilibrium will be reached where, as soon as product is released from the enzymes active site, a new substrate molecule will enter the active site. At this production of [ES] is said to be saturated, meaning it has a constant value which does not change with time. (3) This is said to be the steady state, or bottleneck, condition where all active enzyme sites are occupied. From this condition and the fact that matter is conserved, one can derive the rate law: (4) This is the Michaelis-Menton equation, where the Michaelis constant KM=(k-1 + k2)/k1. This value in a physical context is the substrate concentration midway between zero substrate and the concentration at which the reaction rate has become saturated. Also in the equation Vmaxk2E0 which is said to be the maximum velocity of the reaction. Here, v is the rate of the steady state enzyme reaction. In order to measure the reaction rates, the concentration of product or substrate must be observed as a function of time. It is expected that the concentration vs. time plot will be initially linear until the substrate is beginning to be used up where it would then level off to a constant value. p-nitrophenyl phosphate is chosen as the substrate because a product of its dephosphorylation, nitrophenolate anion has a high molar absorptivity in the blue wavelengths of visible light. This allows for the use of Beers Law to calculate concentration of the product from the absorbance at a specific wavelength of light. A410 = ÃŽ µ410,NPA l cNPA (5) Here, A is the absorbance at a wavelength of 410nm, l is the light path through the solution, ÃŽ µ is the molar absorptivity of the solution and c is the concentration. Thus, by observing the change in absorbance as a function of time, it is possible to observe the increase in product as a function of time. Once the reaction rates at each initial substrate concentration are known, it is necessary to determine the parameters Vmax and KM in the Michaelis-Menton equation (Equation 4) in order to fit the data to a mathematical trend. This nonlinear fit is difficult to make without first having reasonable estimates of Vmax and KM. However, by rearranging Equation 4, it is possible to linearize the equation such that reasonable approximations of the parameters can be obtained by performing a simple linear least-squares regression. One such linearization produces the Eadie-Hofstee plot of the form: v = Vmax KM (6) This equation can be used to give reasonable approximations of the two parameters, which can then be optimized to produce the values of Vmax ­ and KM ­. This optimization is performed by comparing the estimated rate from Equation 4 using the approximate values for the two parameters to the actual rate at different concentrations. A ÃŽ §2 is defined to be the sum of the deviations from the actual observations. A computer can be used to minimize this value by varying Vmax and KM where the values for these two parameters at the minimized ÃŽ §2 are the best approximations. The error in these values is found by minimizing the ÃŽ §2 at several values of Vmax and KM by varying the other parameter. A plot of these points can be used to determine the 95% confidence intervals for these values. Competitive inhibition is the process by which molecules that resemble the substrate can bind to the active site of the enzyme, establishing a competition between the substrate and this molecule for active sites on the enzyme. HPO4- is a product of the hydrolysis of NPP which acts as an inhibitor to the enzyme reaction. The effect of the addition of phosphate on the rate can be expressed as follows: (7) Here, all variables are the same as in Equation 4, where KI is the inhibition constant. Experiment An Ocean Optics USB 400 spectrophotometer is used to take all absorbance readings. All parts of the experiment take place at atmospheric pressure and are open air. In order to establish a basis of comparison, the absorbance at 410 nm is taken for nitrophenolate anion, NPA, the pure product of the enzyme reaction. From this, the molar absorptivity constant can be determined for NPA which can be used to determine the concentration of NPA in solution. Several solutions with a range of concentrations of the substrate nitrophenyl phosphate, NPP, are necessary to observe the effect of substrate concentration on the rate of the enzyme reaction. The concentrations are chosen such that they span the range of the Michaelis-Menton plot. Upon the addition of enzyme to each solution, the concentration of NPA as a function of time is recorded by taking the absorbance reading at 410 nm at each time step. The reaction for each initial NPP concentration is charted for a sufficiently long time such th at an accurate least-squares fit can be made for the plot of concentration as a function of time. From this plot, the initial reaction rates for each NPP concentration can be determined and fit to an Eadie-Hofstee plot to determine approximate values for V and KM. To observe the inhibiting effect of phosphate on the enzyme reaction, several solutions with a range of phosphate concentrations all with equal concentrations of NPP must be prepared. Then, upon the addition of enzyme to the solutions, the concentration of NPA as a function of time is observed via the absorbance readings. It is necessary to keep the initial substrate concentration constant in this part so that the variation in the reaction rate can be attributed to only the variation in phosphate concentration. Discussion of Results As expected, increasing the initial substrate concentration served to increase the rate of product formation in the hydrolysis of nitrophenyl phosphate by an alkaline phosphatase enzyme. This can be seen clearly in Figure 1 where the slope of the graph of product (NPP) concentration as a function of time increases as enzyme concentration increases. For the trials with the three highest initial substrate concentrations, the enzyme concentration was half that used in every other run, meaning that the rate of reaction for these trials must be doubled for comparison purposes. This explains why the slopes of these lines are approximately half of what would be expected in Figure 1. Figure : The plot demonstrates that as substrate concentration increases, so too does the rate of product formation In order to determine the rate of reaction, a second order trend is fit to the data where the linear term in the equation is taken to be the rate of product formation. A second order least squares regression is used to fit the data because the rate of reaction is not truly constant over the timeframe observed. It is expected that the data will have a very slight negative concavity as, by Equation 2, the substrate concentration is decreasing at the same rate as the increase in NPA, leaving less NPP to form the enzyme-substrate complex which produces NPA. This means that the rate should decrease as a function of time the second order regression is used to correct for this fact, leaving the linear term to describe the rate of reaction. Figure 2 (attached) displays the approximate second order trends for NPA concentration as a function of time for each initial NPP concentration. These are only approximate trends as these may not be rigorously calculated, and in any case are over a small er range than that used in subsequent calculations. A more rigorous second order least-squares regression is performed to obtain the reaction rates for each initial substrate concentration. The rates along with the standard deviations for each rate are tabulated in Table 1. As stated previously, it has clearly been shown that as initial substrate concentration is increased, so too does the rate of the reaction. Additionally, the second order linear trend provides a very strong fit to the data. This is evidenced by the fact that the standard deviations of the rates are all 8 or 9 orders of magnitude smaller than the rate, meaning there is very little variance in the data from the trend calculated. Table 1: Enzyme Reaction Rate as a function of Substrate concentration [S0]/M Rate (M/sec) Rate SD 3.23E-03 3.94E-07 1.25E-15 1.61E-03 3.52E-07 2.50E-16 8.06E-04 2.96E-07 4.54E-16 4.03E-04 2.40E-07 4.77E-16 2.42E-04 1.73E-07 2.73E-16 1.45E-04 1.29E-07 2.58E-17 6.45E-05 7.97E-08 7.56E-17 3.23E-05 4.13E-08 4.78E-17 Once the rates at each initial NPP concentration are known, it is possible to attempt to describe the initial rate of the enzyme reaction as a function of initial substrate concentration. This relation can be described by Equation 4, and so the parameters Vmax and KM must be obtained. As stated previously, it is difficult to perform a nonlinear regression to describe rate as a function of time without having reasonably close guesses for these two parameters. By the process described previously whereby Equation 5 is used to linearize the data, we obtain the Eadie-Hostee plot displayed in Figure 3. Figure 3: The Eadie-Hofstee plot linearizes the data such that estimates of Vmax and Km can be obtained As can be seen in the figure, this method produces a roughly linear plot. By performing a linear least squares fit on the data, we can obtain guesses for the two parameters. Equation 6 makes it apparent that the slope of the plot is -KM and the intercept is Vmax. An analysis of the units bears this out: Vmax has units of M/sec (as does the rate because Vmax is the maximum initial rate of reaction at which the enzyme becomes completely saturated), and KM has units of M (as does substrate concentration because KM is the concentration at which the reaction rate is half that of Vmax). The intercept and slope of the graph also have units of M/sec and M, respectively. From the plot, it is estimated that KM = 2.90*10-4 M and Vmax = 4.10*10-7 M/sec. Using these values for the parameters in the Michaelis-Menton equation (4), a decent fit of the data is obtained as seen in Figure 4. However, it is clear from the plot that the values for both parameters are too low. The plot begins to approach a value which is too low as the plot from the formula falls below the final data point. This suggests that the value of Vmax is too low. Additionally, the plot rises too quickly at low substrate concentrations which would cause KM to occur too early, as does the lower value of Vmax. Figure 4: The approximate values of Vmax and Km from the Eadie-Hofstee plot produce only a rough fit of the data These apparent inaccuracies in the values of Vmax and KM are most likely resulted from the fact that the Eadie-Hostfee plot does not use two separate variables on each axis. However, clearly these values are relatively close to the correct value as the plot roughly fits the data. By the process described previously, a computer can be used to produce more accurate values of Vmax and KM by minimizing the ÃŽ §2 value, which is the sum of the squares of the deviations from the data by the value predicted in the formula. Minimizing ÃŽ §2 by varying the two parameters gives the values in Table 2. Table 2: Comparison of Vmax and Km values from Eadie-Hofstee plot and non-linear regression Eadie-Hofstee Non-linear Reg. Pos Error Neg Error Vmax (M/sec) 4.10E-07 4.28E-07 .32E-07 .28E-07 Km/M 2.90E-04 3.33E-04 .47E-04 .58E-04 As expected, the values of both parameters have increased, where Vmax = 4.28*10-7 and where KM = 3.33*10-4. The positive and negative errors for these two parameters are obtained by the process described above. At different values of each parameter, the ÃŽ §2 value is minimized while varying only the other variable. The plots of this process are appended. The confidence interval is taken to be 4.28*ÃŽ §2; that is the values at which these graphs cross this value corresponds to the lower and upper limits of each parameter. This error is also recorded in Table 2. Then by using Equation 4, one can use the multiplicative formula for error to determine error bars for the data points. These errors are tabulated in Table 3 for each initial substrate concentration. Table 3: Enzyme Reaction Rate as a function of Substrate concentration with Errors from Km and Vmax [S0]/M Rate (M/sec) pos error neg error 3.23E-03 3.94E-07 6.29E-08 7.33E-08 1.61E-03 3.52E-07 5.62E-08 6.55E-08 8.06E-04 2.96E-07 4.73E-08 5.51E-08 4.03E-04 2.40E-07 3.83E-08 4.47E-08 2.42E-04 1.73E-07 2.76E-08 3.22E-08 1.45E-04 1.29E-07 2.06E-08 2.40E-08 6.45E-05 7.97E-08 1.27E-08 1.48E-08 3.23E-05 4.13E-08 6.60E-09 7.68E-09 Using these corrected values for Vmax and KM, a more accurate formula to describe the data is obtained. Figure 5 clearly shows that the plot using these new values provides a much better fit to the data than does the plot of the approximate values for the parameters. All of the issues seen in the first plot are no longer present, and the formula clearly falls well within the error bars on each data point. Despite lacking a quantitative means of expressing the quality of the fit, it is possibly to qualitatively state by looking at the plot that the formula with the determined parameter values closely matches the experimental data. Figure 5: The optimized values of Vmax and Km from the estimates given by the Eadie-Hofstee plot produce a strong fit Finally, having confidence in the ability for the Michaelis-Menton equation to describe the effect of initial concentration on the rate of reaction, it is possible to study the effect of the addition of an inhibitor species on the rate of the reaction. Keeping the initial concentration of substrate fixed, the concentration of inhibitor in solution was varied. As would be expected, the addition of inhibitor species greatly reduced the rate of product formation. This is shown in Table 4. Table 4: Determination of mean inhibition costant Ki [I]/M Rate (M/sec) Km app/M Ki/M 0 2.40e-7 3.33e-4 0 3.23E-03 2.34E-08 6.84E-03 1.62E-04 6.45E-03 1.69E-08 9.80E-03 2.27E-04 9.68E-03 7.61E-09 2.14E-02 1.47E-04 [S]/M Avg Ki/M 1.79E-04 4.03E-04 SE .25E-04 Also observed is that the addition of more inhibitor species results in an increasingly reduced rate of product reaction. This makes sense because as more inhibitor species exists in solution, there are more molecules that can bind to the enzymes active sites, thereby inhibiting the formation of the enzyme-substrate that is necessary for product formation. As a result of the rate decreasing as the inhibitor concentration is increased, the apparent KM value greatly increases. This makes sense because the substrate would have to be significantly more concentrated to effectively compete and reach the concentration at which the reaction rate is half that of Vmax. From Equation 7, it is possible to calculate the value of KI from the inhibitor concentration, the rate and Vmax. Averaging the values of KI for each inhibitor concentration gives a = (1.79 + 0.25)*10-4 M. Conclusion The alkaline enzyme-catalyzed hydrolysis of nitrophenyl phosphate is a first order reaction that depends on the initial concentration of substrate in solution when the concentration of enzyme is kept constant. A second order least-squares regression gives the initial rate of reaction as a function of time, where the rate of product formation increases as the initial concentration of substrate increases. The Eadie-Hosfstee plot was used to approximate the parameters Vmax and KM that are necessary to describe the relation between substrate concentration and rate of reaction. Optimizing these parameters through the minimization of a X2 value gives Vmax = 4.28*10-7 and KM = 3.33*10-4. The error in these parameters can be determined by each parameter separately to minimize the X2 value at different values for each parameter. These values for the parameters in the Michaelis-Menton equation produce a qualitatively strong fit for the data. The addition of an inhibitor species served to decre ase the rate of product formation where the increase in inhibitor concentration results in a decrease in rate. Using the Michaelis-Menton equation, the inhibition constant KI is found to be = (1.79 + 0.25)*10-4 M.

Television and Media Essay - TV Violence and the V-Chip :: Media Argumentative Persuasive Argument

TV Violence and the V-Chip America has the highest crime rate in the world. Along with that crime rate is also the substantially high violence rate. Why is violence becoming and everyday event in our society? When you flip on the "tele" and tune into the news, the highlight of every show is somehow directly related or connected to violence. We see it every evening and perhaps say "Oh my gosh, how terrible." and then forget all about it two minutes later. Or perhaps we don't even make any comments at all, just a simple grunt or "..huh..". This numbness to violence is very scary and very real. Why is it then that America has the most crime and violence. Why not Switzerland or Australia. Are we not as civilized and advanced as they? I believe it is this numbness to violence that has made America so violent. When I think back to my childhood and remember television I remember watching such programs as "Sesame Street", "Mr. Rogers", and "Scooby - Doo". I have nothing but pleasant memories filled with happiness, peace, understanding, and learning. When you watch children's programs today you see senseless violence often as the first means of solving a problem. The classic view of "good" versus "evil" is the basis of these shows with violence as the answer. When children watch these programs they copy the actions and "morals" of these shows depicting "good" and "evil". Children do not know what "good" is or what "evil" is, how can they? This world is not broken into "good" and "evil". "Evil" to children is what opposes them, what does not agree with them, or any other person or thing that poses a possible difficulty. Children must be taught that there are differences in this world. This world is filled with many people holding different beliefs, ideas, and morals. That is what makes this world so unique and colorful. Children need to learn to respect these differences from a very young age. They need to learn to talk out and solve any disagreements or problems through other means than violence. They must not "know" violence as an answer, as if violence was never even an option to consider in solving a problem. I recently became aware of the problem of violence in children when I started observing small children at play at my apartment complex. I had known one small child in particular when he was just learning to speak. I had watched him and talked with him for several years and noticed nothing "violent" nor

Behavioral scientists Essay

Gang violence is a social phenomenon that has caught the interests of behavioral scientists, psychologists and other related fields. At the forefront is the fact that gangs are social groups that have exclusive rules and strict codes of brotherhood which can actually provide the need for belongingness and affiliation as well as security in the harsh life in the city streets. Surprisingly, gangs have been associated with violence for the longest time, the term gang is already perceived as negative and that at present, gang is synonymous to violence, criminal acts and substance abuse. People join gangs for various reasons but it has been found that adolescents who have been victims of abuse, have dysfunctional family systems, school drop-outs and those in foster care generally join gangs more than the normal teenager. Thus, the final project is geared towards bringing about behavior change for adolescents at risk of joining gangs and or has a tendency for violence. Before drawing up a concrete behavior change program, it is important to examine how this could be brought about by factors like motivation and cultural awareness. Motivating people to change is not an easy feat, generally, if a person is set in his/her ways, then asking them to change something that they do not perceive to be evil or negative is a futile act. Central to the concept of motivation is that the goal offered to the individual must be meaningful to him/her, one that is personally desired and can be owned as a personal decision. This is where choice comes in, when a person is confronted with a choice; his/her reaction to it depends on their circumstances and present state of mind (Iyengar & Lepper, 1999). In this context, choosing to change their behavior should come from their internal desire to change, to become better and to be removed from their present difficulties. For example, if the behavior that is targeted to be modified is expressions of anger, it makes sense to the person to change this if he/she can realize that his/her actions hurt other people and that it also causes people to avoid them and hence lead to feelings of isolation and loneliness. Gangs are often formed around cultural groups, that is one gang can be comprised of Latinos, others are blacks, and others Asians and or whites. Thus, a program for behavior change should also consider the different cultural underpinnings of the gang and its members, if the gang is made up of black Americans, then asking them to join a program geared towards changing them, might be construed as culturally motivated, they have to be changed because they are blacks. There is much emotionality when it comes to culturally specific gangs and it cannot be denied that emotion may get in the way of participating in a program that is designed to change them (Markus & Kitayama, 1991) Motivation is also said to be affected by culture, one has to be able to correctly identify the cultural background of the gang or the participants of the project so as to provide a more culturally relevant and sensitive program. Lastly, motivation can be defined as extrinsic and intrinsic, it has been generally accepted that intrinsic motivation is more positive, more important and influential than extrinsic motivation thus the behavior change program should appeal to the intrinsic motivation of the participants. Intrinsic motivation is the feelings and behavior that drives the person to act in a certain way or to commit to a behavior change program. Internal means that it is something personal and valued by the person, it can be the desire for self-awareness, confidence and achievement, whereas extrinsic motivations are physical and tangible like prestige, money and awards (Sansone & Harackiewicz, 2000). The behavior change program should be designed to spark the intrinsic motivation of the participants, thus conducting an orientation seminar will introduce the participant to the program and letting them experience how good it is to be able to know who they are, to know that they mattered and someone cared for them would facilitate rapport and trust between the researcher and the participant. If the concepts of choice, culture and motivation will be adequately examined and integrated into the planned program, then surely the project would be a success. References Iyengar, S. & Lepper, M. (1999). Rethinking the role of choice: A cultural perspective on intrinsic motivation. Journal of Personality and Social Psychology, 76, 349-366. Markus, H. & Kitayama, S. (1991). Culture and self: Implications for cognition, emotion, and motivation. Psychological Review, 98, 224-253. Sansone, C. & Harackiewicz, J. (2000). Intrinsic and extrinsic motivation: The search for optimal motivation and performance. San Diego: Academic Press.

Molar Mass of Oxygen Essay

Applying the individual % of elements in Water to the molar mass Conclusion____________________________________________________________ In conclusion the experimental value of the molar mass of oxygen is. To achieve this result, we wrote the chemical reaction, compared the ratio of mole between and, find the mole produced by water using the formula, calculate the molar mass from the mol value, calculate the % of individual elements in water, and finding oxygen’s molar mass from the overall molar mass. Analysis & Evaluation ___________________________________________________ -In analysis, our results show an unreasonable result. The majority of the failure is from the volume result. From Avogrado’s law we know that. As such, because the average volume (0.051 L) was low, the mol resulting from it is also low. A small mol results in a large Mr value, or in our case the Mr of Oxygen is too high. -Another point to that is that if the experiment was assuming r.t.p, our results prove to be incorrect again. If we compared the mol, the actual mol results of andusing the ideal gas laws is different than if we calculated using normal Stoichiometry. From Stoichiometry, the actual mol of is, and if we compared it to a ratio of 2:2, the actual mol value of is also 0.138 mol. However in our experiment using the gas law, our mol result was. Again this is due to the fact of the low amount of volume recorded. -In addition to that point, from the section to: Calculate molar mass of Water using the mass of Hydrogen Peroxide , another flaw to the experiment was the amount of uncertainty in the result. From the section we apply the ‘law of conservation of mass’ stating that no mass is created or destroyed. Or in this experiment’s case, most of the mass decomposes into Oxygen gas and finally results in the volume of water displaced from the process. However as shown from the low amount of volume our group collected, this can result in two conclusions. The first conclusion is that most of the oxygen gas that eventually turns into the volume of water left is lost to the surroundings (from the test tube openings) OR the second conclusion is that our group did not wait long enough and thus lost some potential volume results. -To evaluate, the major flaw to the experiment was the value of the data collected. Part of the reason was because we used Vaseline as a tool to reduce the amount of energy (in the form of the Oxygen gas) to the surroundings. Vaseline is a good measure to do so, however a better alternative is probably to increase the number of trials, to have a more close system that may significantly reduce the uncertainties, and to maybe reduce the length of rubber tube (by reducing the length of rubber tube the amount of water left is reduced). References IB- Foundation books. Raymond Chang (pg: 87, 181, 182, 191.etc)

Glass Managerie essays

Glass Managerie essays The Glass Managerie In The Glass Managerie,by Tennesee Williams, symbols are used to describe the characters in the play. Laura, a very frail and insecure character from the play, lives in a world of illusions. Crippled with one leg shorter than the other from a childhood illness, she lives her life through her collection of glass animals. They provide Lauras refuge from reality. One particular glass animal the fragile and rare unicorn symbolizes the characters sufferings. The brilliant use of the imagery of the glass unicorn helps express the emotional anguish of Laura. Only when the unicorn loses its horn, and become like the other glass horses does Laura too break free from her fantasy world and snap into reality and realize that she is not a freak as she thought she was. The obsession that Laura has for her glass ornaments is first eminent in scene two where she is seated in her delicate ivory chair, washing and polishing her collection. It is also in this scene where it is obvi ous that her mother has criticized her many times for her unusual fascination of the glass animals because at the sound her mother approaching, she nervously shoves away them away. And before entering the room, the mother, Amanda, peeks through the door to see what Laura is doing and purses her lips, opens her eyes very wide, rolls them upward and shakes her head (11). Amanda scorns Laura for deceiving her by pretending to go to business school even though she dropped out. Her reason was that it frightened her so bad it made her sick in the stomach (35). Because Laura does not have the courage to live a normal sociable life, the glass animals in this scene represent her hopes and dreams of another life. This fantasy life that Laura longs for is probably why she thought she could get away with deceiving her mother about going to business school. In scene three, the glass ornaments repres...