results gained from accurate experimental procedures. Aim The aim of this experiment is to investigate the rate at which iodine is formed when the concentration and temperature of the reactants are varied, and to attempt to find the order and activation energy. The Chemistry 'THE IODINE CLOCK' - This is the experiment that will be used to investigate reaction rates, and it is a reaction between acidified hydrogen peroxide and potassium iodide: 2H+(aq) + 2I¯ (aq) + H[-1] 2O2 (l) ÕI2 (aq)
temperature of the solution in which the reaction is taking place. From these results, I hope to draw conclusions as to the effects of these changes to the environment of the reaction on the rate and also determine the order of the reaction and the activation enthalpy. Background information The rate of a reaction is determined by a number of factors. These include: pressure, temperature, concentration of reactants, surface area of reactants, presence of a catalyst and radiation. The effect of these
Theoretical Approaches to Speech Production There are two main theories of Speech production, Spreading Activation Theory - SAT (Dell, 1986: Dell & O’Seaghdha, 1991) and Word- Form Encoding by Activation and Verification – WEAVER++ (Levelt et al., 1989: 1999). The SAT theory was devised by Dell (1986) then revised by Dell & O’Seaghda (1991). The theory works on a 4 level connectionist model: parallel and dynamic. The Semantic level is the meaning of what is going to be said. The Syntactic
and serotonin, which helped to develop a greater understanding of the role serotonin plays as a neurotransmitter in the brain (Nichols, 2004). Today it is believed that LSD (and other hallucinogens) stimulate 5-HT2A receptors (Kalat, 2004). Activation of these receptors causes cortical glutamate levels to increase. This is presumed to be a result of a "presynaptic receptor-mediated release" from neurons in the thalumus (Nichols, 2004). Early studies proposed that LSD antagonized the effects
electromyelogram (EMG), which measure brainwaves, eye-movement, and muscle tone, respectively. REM is categorized by high-frequency, low-amplitude, more irregular waves in EEG, rapid, coordinated movement in EOG, and weak EMG. During this type of sleep, brain activation heightens, breathing and heart rates increase, and body movement is paralyzed. Because the person is highly aroused, like in waking, but also very asleep, REM sleep is also called paradoxical sleep (6). Although dreams and REM are not synonymous
understand how it is produced. Fission is the initial step. It is the splitting of uranium or plutonium atoms which produces radioactive "fission fragments" and "activation products" (Bertell, 1985). These products then ionize normal atoms, which leads to a sort of domino affect microscopically. This chain reaction can also cause activation products to be produced by causing chemicals in the air,... ... middle of paper ... ... 1982. http://www.public.iastate.edu/smevela/policy.html. Glasstone
are based on language-like constructs. Since the arrival of connectionism another representation has been proposed that of sub-symbolic representation. Here mental representations, according to Eysenk and Keane (2002) are “distributed” patterns of activation in a connectivist network. Historically, mental representations have been interpreted by analogy with physical representations, i.e. descriptions and classifications devised for physical representations have been applied to mental representations
vision is even more complex. Cones (the light adapted photoreceptor) contain three different photopigments, red, green, and blue, each corresponding to a particular wavelength of light (2). Color is a property of three things: the ratio of red/green activation, blue response, and value or lightness (3). The brain utilizes visual inputs to determine each of these, thus generating the characteristic color. One of the most important (and most interesting) conclusions of the biology of vision is that color
brain that show activity levels in the brain. These imaging techniques such as f-MRI and PET scan actually create images of how active different parts of the brain are. Some studies with these kinds of techniques have suggested that the patterns of activation in the brains of depressed people are different than those who are not. These tests can help doctors and researchers learn more about depression and other mental illnesses. Since this research is fairly new, it is not yet used to diagnose clinical
Introduction: Enzymes are protein molecules that function as biological catalysts that can help break larger molecules into smaller molecules while remaining unchanged themselves. They speed up the chemical reactions by lowering the energy of activation barrier, are specific to one molecule. The enzyme’s specificity arises from its active site, an area with a shape corresponding to the molecule with which it reacts (the substrate). The shape of the enzyme where the chemical binds only allows the
programming to subscribers throughout the United States. Their primary source of revenue is through subscription fees, with most of their customers subscribing to SIRIUS Satellite Radio on either a monthly or a yearly basis. They also derive revenue from activation fees, advertising sales on non-music channels and the direct sale of SIRIUS radios, which are currently sold in over 6,500 retail locations around the nation. As of December 31, 2004, SIRIUS has had over 1.2 million subscribers and 375 employees
protection for plants, and when we consume them, we benefit from their antioxidant power. Antioxidants help the body’s cells resist damage from free radicals (Cleveland Clinic, 2004). The reason for the benefits of cocoa is that it controls the activation of nitric oxide synthase, an enzyme, that keeps blood vessels open allowing the blood to flow. Flavonoids may also lessen stiffening of the blood vessels, which is a common side-effect of aging (WebMD, 2004). It is to be noted that white and
can see that pain is a perception, sort of like seeing and hearing. When pain is processed there are a number of brain structures activated, commonly referred to as the "central pain matrix" (2). It may seem irrelevant to delve into pain signal activation in the brain since it is seemi... ... middle of paper ... ...that one's entire perception of pain may be conscious in origin and simply correlate to the mechanisms of the brain, rather than stem from just the brain entirely. References
large protein molecules, with complex three-dimensional shapes. Enzymes increase the rates of reactions by reducing the free energy of activation, so that the barrier to a reaction occurring is lower in the presence of an enzyme. The combination of enzyme and substrate creates a new energy profile, for the reaction, with a lower free energy of activation. Once the products have been formed, they leave the active site of the enzyme, which is left free to combine with a new substrate molecule
states that that the different particles need to collide with each other in order to react. However, they do not react if they collide without sufficient energy, and therefore the more energy a particle has, the more likely it is to react. The activation energy is the minimum amount of energy required by a particle in order to react. When a rate of reaction is improved, the likelihood of the collision of particles is higher and the energy at which they collide is increased. The importance
substrates for the insulin receptor, the best-studied of which is insulin receptor substrate 1 or IRS-1. When IRS-1 is activated by phosphorylation, a lot of things happen. Among other things, IRS-1 serves as a type of docking center for recruitment and activation of other enzymes that ultimately mediate insulin's effects. A more detailed look at these processes is presented in the section on Insulin Signal Transduction. Insulin and Carbohydrate Metabolism Glucose is liberated from dietary carbohydrate
Since the beginning of the industrial revolution early in the nineteenth century, our ability to change the world around us has become profound. At first, the impact on our planet was almost imperceptible, but as we have grown both in number and technological capability, that influence has grown with us. Lately, the effects of our increased activity have begun to manifest themselves in a multitude of subtle, and some not so subtle ways: we have thinned the ozone layer and may now be starting to change
yours That the zealous Trojans take me for you and quickly Withdraw from the fighting." Because Achilles refused to help the Achaeans battle the Trojans, a discontented Patroclus took the matter into his own hands by requesting activation into battle disguised as Achilles in the hope of sending the Trojans into a full retreat from the sight of him. It is apparent that Patroclus was willing to fight although the odds were greatly against him. His vehemence towards the
DHL: Global Market Leaders Abstract This paper is about customer relationship polices and how they are key to the success of a business. It talks about businesses taking care of their internal/external customers’ needs, receiving and handling customer feedback, and meeting customer’s demanding expectations. DHL: Global Market Leaders Introduction Marketing is the competitive/creative business strategy designed to captivate/hold the attention of individuals or companies towards an exchange
the United States. WHAT IS AN FTZ? A foreign trade zone is a restricted access site authorized by the Foreign-Trade Zones Board, which consists of the treasury and commerce secretaries (the secretary of commerce chairs the board). FTZs, upon activation under regulations of the U.S. Customs Service, are secure areas under U.S. Customs supervision. These zones are at or near U.S. Customs ports of entry. Formal customs entry procedures don?ft apply in these zones, although FTZs are within the territory