Technical Description of the Process of Sleep Essay

Technical Description of the Process of Sleep - Essay Example Other equipment used in support with EEG, is one that measures eye movements that is called electrooculogram or EOG. The Electromyogram (EMG) on the other hand measures the muscle tension under the chin of a subject. As stated in Sleep-Information about Sleep, the practice in studying sleep pattern is EEGs, EOGs, and EMGs are recorded simultaneously on a continuous moving chart paper. This then determines the activities of three aspects – the muscle activity, the brain activity, and eye movements. The NREM sleep and REM sleep occurs in a cyclic manner during sleep state (Sleep, Sleep Disorders, and Biological Rhythms. They interchangeably happen to an individual during his sleep. Sleep starts with periods of NREM and then REM. NREM state has four different stages as determined by the frequency and amplitude (brain wave’s magnitude of periodic variation) of the brain activity. The first NREM stage is characterized by very light sleep. NREM Stage 2 has special brain waves called sleep spindles (burst of brain activity visible on an EEG) and K-complexes (brief high-voltage peak in EEG as defined by Wikipedia.org). Stage 3 and 4 of NREM is described by slow brain waves and in Stage 4 of NREM, it is hard to wake the person up. NREM stage 4 is deep sleep and cannot easily be awakened by external factors. During NREM, the muscle activity remains active and body function is the same with the waking state. The difference is that there is no eye movement.

Oligopoly and monopoly Essay Example for Free

Oligopoly and monopoly Essay An oligopoly is an intermediate market structure between the extremes of perfect competition and monopoly. Oligopoly firms might compete (noncooperative oligopoly) or cooperate (cooperative oligopoly) in the marketplace. Whereas firms in an oligopoly are price makers, their control over the price is determined by the level of coordination among them. The distinguishing characteristic of an oligopoly is that there are a few mutually interdependent firms that produce either identical products (homogeneous oligopoly) or heterogeneous products (differentiated oligopoly). Mutual interdependence means that firms realize the effects of their actions on rivals and the reactions such actions are likely to elicit. For instance, a mutually interdependent firm realizes that its price drops are more likely to be matched by rivals than its price increases. This implies that an oligopolist, especially in the case of a homogeneous oligopoly, will try to maintain current prices, since price changes in either direction can be harmful, or at least nonbeneficial. Consequently, there is a kink in the demand curve because there are asymmetric responses to a firms price increases and to its price decreases; that is, rivals match price falls but not price increases. This leads to sticky prices, such that prices in an oligopoly turn out to be more stable than those in monopoly or in competition; that is, they do not change every time costs change. On the flip side, the sticky-price explanation (formally, the kinked demand model of oligopoly) has the significant drawback of not doing a very good job of explaining how the initial price, which eventually turns out to be sticky, is arrived at. Airline markets and automobile markets are prime examples of oligopolies. We see that as the new auto model year gets under way in the fall, one car manufacturers reduced financing rates are quickly matched by the other firms because of recognized mutual interdependence. Airlines also match rivals fares on competing routes. In oligopolies, entry of new firms is difficult because of entry barriers. These entry barriers may be structural (natural), such as economies of scale, or artificial, such as limited licenses issued by government. Firms in an oligopoly, known as oligopolists, choose prices and output to maximize profits. However, firms could compete along other dimensions as well, such as advertising, location, research and development (RD) and so forth. For instance, a firms research or advertising strategies are influenced by what its rivals are doing. When one restaurant advertises that it will accept rivals coupons, others are compelled to follow suit. The rivals responses in an oligopoly can be modeled in the form of reaction functions. Sophisticated firms anticipating rivals behavior might appear to act in concert (conscious parallelism) without any explicit agreement to do so. Such instances pose problems for antitrust regulators. Mutually interdependent firms have a tendency to form cartels, enabling them to coordinate price and quantity actions to increase profits. Besides facing legal obstacles, cartels are difficult to sustain because of free-rider problems. Shared monopolies are extreme cases of cartels that include all the firms in the industry. Given that mutual interdependence can exist along many dimensions, there is no single model of oligopoly. Rather, there are numerous models based on different behavior, ranging from the naive Cournot models to more sophisticated models of game theory. An equilibrium concept that incorporates mutual interdependence was proposed by John Nash and is referred to as Nash equilibrium. In a Nash equilibrium, firms decisions (i. e. , price-quantity choices) are their best responses, given what their rivals are doing. For example, McDonalds charges $2. 99 for a Value Meal based on what Burger King and Wendys are charging for a similar menu item. McDonalds would reconsider its pricing if its rivals were to change their prices. The level of information that firms have has a major influence on their behavior in an oligopoly. For instance, when mutually interdependent firms have asymmetric information and are unable to make credible commitments regarding their behavior, a prisoners dilemma type of situation arises where the Nash equilibrium might include choices that are suboptimal. For instance, individual firms in a cartel have an incentive to cheat on the previously agreed-upon price-output levels. Since cartel members have nonbinding commitments on limiting production levels and maintaining prices, this results in widespread cheating, which in turn leads to an eventual breakdown of the cartel. Therefore, while all firms in the cartel could benefit by cooperating, lack of credible commitments results in cheating being a Nash equilibrium strategy—a strategy that is suboptimal from the individual firms standpoint. Models of oligopoly could be static or dynamic depending upon whether firms take intertemporal decisions into account. Significant models of oligopoly include Cournot, Bertrand, and Stackelberg. Cournot oligopoly is the simplest model of oligopoly in that firms are assumed to be naive when they think that their actions will not generate any reaction from the rivals. In other words, according to the Cournot model, rival firms choose not to alter their production levels when one firm chooses a different output level. Cournot thus focuses on quantity competition rather than price competition. While the naive behavior suggested by Cournot might seem plausible in a static setting, it is hard to image real-world firms not learning from their mistakes over time. The Bertrand models significant difference from the Cournot model is that it assumes that firms choose (set) prices rather than quantities. The Stackelberg model deals with the scenario in which there is a leader firm in the market whose actions are imitated by a number of follower firms. The leader is sophisticated in terms of taking into account rivals reactions, while the followers are naive, as in the Cournot model. The leader might emerge in a market because of a number of factors, such as historical precedence, size, reputation, innovation, information, and so forth. Examples of Stackelberg leadership include markets where one dominant firm dictates the terms, usually through price leadership. Under price leadership, the leader firms pricing decisions are consistently followed by rival firms. Since oligopolies come in various forms, the performance of such markets also varies a great deal. In general, the oligopoly price is below the monopoly price but above the competitive price. The oligopoly output, in turn, is larger than that of a monopolist but falls short of what a competitive market would supply. Some oligopoly markets are competitive, leading to few welfare distortions, while other oligopolies are monopolistic, resulting in dead weight losses. Furthermore, some oligopolies are more innovative than others. Whereas the price-quantity rankings of oligopoly vis-a-vis other markets are relatively well established, how oligopoly fares with regard to R and D and advertising is less clear.

Predictability of Earnings and Reversion of Profitability

Predictability of Earnings and Reversion of Profitability 1. INTRODUCTION, RESEARCH QUESTION AND CONTRIBUTION In a competitive environment, economists say there is a mean reversion of profitability. Mean reversion of profitability infers that variation in profitability and earnings can be predicted. Although there are some literatures making an effort to find prediction in profitability and earnings, the findings somewhat cannot fully explain those variations. Early researches (Beaver 1970; Brooks and Buckmaster 1976; and Lookabill 1976) did not test the prediction formally. When there were formal tests, models were mostly time-series and identified only companies with long-earning histories (20 years). This approach causes the issue that long-term survivors might not represent all the firms. Furthermore, 20 years of data on earnings is an inaccurate estimation of the time-series model. Thus, the results found are statistically weak (Lev 1969; Freeman, Ohlson, and Penman 1982). There are some later researches attempting to identify those variations as well. Freeman et al (1982), Collins and Kothari (1989), Easton and Zmijewski (1989), Ou and Penman (1989), Elgers and Lo (1994) and Basu (1997) found that cross-sectional tests constructed more consistent evidence of predictability. However, Elgers and Lo (1994) found the unrealistic assumption that there is no correlation among companies due to changes in earnings and profitability. Moreover, most existing literatures do not investigate connection of the predictability of profitability and that of earnings. Contrastingly, like Freeman et al. (1982) and Lev (1983), this research paper is to answer the question: Is much of what is predictable about earnings due to the mean reversion of profitability? The result confirms the answer to question is yes. Those results are applicable to the real world. Therefore, the main contribution is the confirmation of economists presumption that there is a mean reversion of profitability in a competitive environment. 2. Data and methodology 2.1 A First-Pass Partial Adjustment Model for Profitability This test uses a simple cross-section partial adjustment regression in profitability changing for each year t from 1964 to 1995. This regression from t to t+1 is as followed   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (1a)   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚   (1b) where is total book assets of firm at the end of year t,is earnings before interest,is profitability measure, is expected value of profitability measure, is profitability change from year t to t+1 and is the profitability deviation from the expected value.   Ã‚  Ã‚   The paper uses a two-step method to identify equation (1). After doing regression to investigate differences in expected profitability among companies, the fitted values from the first-step regression are used as the proxy for in the cross-section regression.   Ã‚  Ã‚   In the first-stage regression, (dividends to book value of equity at the end of year t) is used as proxy for expected profitability, (dummy variable to capture nonlinear relationship of dividends and expected profitability) and (market-to-book ratio to find variation of expected profitability which cannot find by dividend determinants. In the cross-section regression, in (1) is the fitted value from the first-stage regression.   Ã‚  Ã‚   (2)   Ã‚  Ã‚   Due to the high regulation during the sample period (1964-1995), financial companies and utilities are omitted. This paper considers only the firms with more than $10 million assets and more than $5 million book equity. With these exclusions, 2,343 companies per year are taken into account. The interpretation is based on the average slopes and the time-series standard errors of the average slopes. However, with only 33 slope observation from 1964 to 1995, the estimation of autocorrelation is inaccurate. Therefore, this paper uses a less strict approach with t-statistics requirement of about 2.8 rather than the common 2.0. 2.2 A Nonlinear Partial Adjustment Model for Profitability This test is developed to investigate whether there is comparable nonlinearity in profitability characteristics with the hypothesis that the mean reversion of profitability results in the predictability of earnings. The nonlinear partial adjustment model equation is expanded from equation (1). (3)   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   where is the negative deviations of profitability from expected values, is the squared negative deviations, is the squared positive deviations, is negative changes in profitability, is squared negative changes and is squared positive changes. , and are to capture the nonlinearity in the mean reversion of profitability and , and are to capture the nonlinearity in the profitability changes autocorrelation. 2.3 Predicting Earnings Freeman et al. (1982) and Lev (1983) argue that the competition causes mean reversion of profitability. This paper inspects the predictable changes in earnings and how much of the predictability brings the nonlinearity of mean reversion in profitability. The dependent variable is change in earnings, . The regression of change in earnings is (4)   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   where is negative changes in earnings, is squared negative changes in earnings and is squared positive changes in earnings. , and are to capture the nonlinearity in the earning changes autocorrelation. 3. results 3.1 A First-Pass Partial Adjustment Model for Profitability The negative slope of implies that there is a nonlinear relationship of dividends and profitability. The significant positive slope of confirms the hypothesis that market-to-book ratio investigates variation of expected profitability which cannot find by dividend determinants.

A Depiction of Three Ages in Robert Frosts The Road Not Taken :: Road Not Taken essays

The Road Not Taken: Depiction of Three Ages  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In his Explicator article, â€Å"Frost’s ‘The Road Not Taken,’† William George suggests that the poem includes â€Å"three distinct ages† of the narrator and focuses on the choices that this person must make at the different stages of his life (230).   George differentiates the primary speaker of the poem, what he calls the â€Å"middle-aged self,† from the younger and older versions, noting that the middle-aged version mocks the other two by taking a more objective stance towards his decision.   The younger and older versions â€Å"are given to emotion, self-deception, and self-congratulation, and both face a decision which the middle-aged speaker sees with more objective eyes than do his younger and older selves† (230).   George demonstrates that, while the middle-aged self is able to view his other selves objectively without delusion and self-aggrandizement, the younger and older selves are incapable of this kind of objectivity in their decision-making.   George’s analysis is broken into two parts;   the first part is an analysis of the relationship between the middle-aged self and the younger self, while the second part is an analysis of the relationship between the middle-aged self and the older self.   In the first part of the article, George suggests that the younger self is faced with choosing between two roads, paths that the middle-aged self understands are very similar; the younger self, however, refuses to accept their equal value and instead deludes himself with the idea of having chosen a less traveled path (230-31).   In the second part of the article, George describes how the older self is faced with choosing between telling the truth about his decision as a youth or lying about it;   while the middle-aged self fully recognizes that the choice of the past was not grand, the older self chooses to cover over this truth through deception and self-aggrandizement (231).

Simple Harmonic Motion Dominic Stone Lab Partner

Experiment 1: Simple Harmonic Motion Dominic Stone Lab Partner: Andrew Lugliani January 9, 2012 Physics 132 Lab Section 13 Theory For this experiment we investigated and learned about simple harmonic motion. To do this we hung and measured different masses on a spring-mass system to calculate the force constant k. Simple harmonic motion is a special type of periodic motion. It is best described as an oscillation motion that causes an object to move back-and-forth in response to a restoring force given by Hooke’s Law: 1) F=-kx Where k is the force constant.Then using two different procedures, we calculate the value of the force constant k of a spring in our oscillating system. We observed the period of oscillation and use this formula: 2) T=2(m/k) Then we reduced the equation to solve for the value of k by: 3) k=4^2/slope â€Å"Slope† represents the slope of the graph in procedure B. k is then the measure of the stiffness of the spring. We can then compare k to that of a vertically stretched spring with various masses M. By using the following equation: 4) Mg=kx Where x is the distance of the stretch in the spring.To find the value of the constant k we take the data from procedure A and graph it. Using this graph, we use equation: 5) k=g/slope We can compare the two values of the constant k. Both values should be exact since we used the same spring in both procedures. Here simple harmonic motion is used to calculate the restoring force of the spring-mass system. Procedure Part A: First, we set up the experiment by suspending the spring from the support mount and measured the distance from the lower end of the spring to the floor.After, we hung 100 grams from the spring and measured the new distance created from the stretch of the spring. We then repeated this step for masses 200 to 1000 grams, by increasing the weight by 200 grams each time. Then we took this data and plotted them on a graph with suspended weight Mg versus elongation x. After plott ing this data we were then able to evaluate the force constant k from the slope of the graph. Part B: First, we suspend 100 grams from the spring and let it lay at rest.When the spring was naturally set in its equilibrium position, we slightly pulled down the weight and recorded the time it took for the weight to complete 10 oscillations and calculated the average period of each oscillation. We then repeated this process for masses 100 to 1000 grams by increasing the weight by 100 grams each time. After we completed this process we plotted a graph of T^2 verses suspended mass m with the data. When then found the intercept at T^2=0 to see how it would compare with the value of negative one-third the mass of the spring.We then also determined the spring constant k by calculating the slope of the graph and compared it with the spring constant k in part B. Data Part A: Mg(Kg/s^2)| X(m)| 1. 96| 0. 39| 3. 92| 0. 63| 5. 88| 0. 86| 7. 84| 1. 11| 9. 8| 1. 36| Part B: M(Kg)| T (s)| T(s)| T^2( s^2)| 0. 1| 8. 24| 0. 824| 0. 679| 0. 2| 9. 87| 0. 987| 0. 974| 0. 3| 12. 74| 1. 274| 1. 623| 0. 4| 14. 57| 1. 457| 2. 123| 0. 5| 16. 23| 1. 623| 2. 634| 0. 6| 17. 49| 1. 749| 3. 059| 0. 7| 19. 21| 1. 921| 3. 69| 0. 8| 20. 26| 2. 026| 4. 105| 0. 9| 21. 69| 2. 169| 4. 705| 1| 22. 89| 2. 289| 5. 24| Data Analysis

Free Essays on Western Expansion

Westward Expansion The Affect on Native Americans Writer and historian Noel Ignatiev posed the question, â€Å"What is the role of westward expansion in American culture?† His answer points the reader in an entirely different direction than a person of average patriotic and historic beliefs would have expected. What was and is our belief about ourselves as we examine the westward expansion are both as enlightening as it is painful. This, of course depends on whose historical perspective it is. The proud history widely recognized by most Americans, focuses on the story of the Puritans quest for freedom and the expansion west as natural extension of this movement to the new continent. It tells of the struggles and successes, colonization of the new world, as well as the heroic fight for independence from England. However, from the perspective of the black slaves or Native Americans, the story of our heritage and the subsequent expansion west is much less than heroic. It is a story of man’s inhumanity to his fellow beings.1 During the nineteenth century just after the War of 1812 there was a significant migration of people with no land and no slaves to remaining lands in the east. Around this time speculators were making a great deal of money selling land, sometimes making ten times what they would pay for it. Professor William Scarborough in an Internet article about the Indians displacement in the 19th century writes of one man, â€Å"Guy S. Whitfield of Alabama, who said he was making a thousand dollars a week for land speculation.† When the land was purchased it need to be cleared and worked. The demand for labor increased and contributed to the growth of the slave trade. â€Å"Mississippi, 1. Noel Ignatiev, â€Å"Noel Ignatiev on the role of westward expansion.† Judgment Day, pars. 1-4 [article online] accessed 16 February 2003. Available from pbs.org/wgbh/aia/part4/4i3098.html. for example, the sla... Free Essays on Western Expansion Free Essays on Western Expansion Westward Expansion The Affect on Native Americans Writer and historian Noel Ignatiev posed the question, â€Å"What is the role of westward expansion in American culture?† His answer points the reader in an entirely different direction than a person of average patriotic and historic beliefs would have expected. What was and is our belief about ourselves as we examine the westward expansion are both as enlightening as it is painful. This, of course depends on whose historical perspective it is. The proud history widely recognized by most Americans, focuses on the story of the Puritans quest for freedom and the expansion west as natural extension of this movement to the new continent. It tells of the struggles and successes, colonization of the new world, as well as the heroic fight for independence from England. However, from the perspective of the black slaves or Native Americans, the story of our heritage and the subsequent expansion west is much less than heroic. It is a story of man’s inhumanity to his fellow beings.1 During the nineteenth century just after the War of 1812 there was a significant migration of people with no land and no slaves to remaining lands in the east. Around this time speculators were making a great deal of money selling land, sometimes making ten times what they would pay for it. Professor William Scarborough in an Internet article about the Indians displacement in the 19th century writes of one man, â€Å"Guy S. Whitfield of Alabama, who said he was making a thousand dollars a week for land speculation.† When the land was purchased it need to be cleared and worked. The demand for labor increased and contributed to the growth of the slave trade. â€Å"Mississippi, 1. Noel Ignatiev, â€Å"Noel Ignatiev on the role of westward expansion.† Judgment Day, pars. 1-4 [article online] accessed 16 February 2003. Available from pbs.org/wgbh/aia/part4/4i3098.html. for example, the sla...