Tell us about the types of housing foundation used today in terms of Essay

Tell us about the types of housing foundation used today in terms of building structure and interior design - Essay Example ce, a house built in a bad soil might require the use of a deep foundation Because of this, an individual is free to choose on the type of foundation to use. The following are some of the popular types of foundations used today: This is a type of foundation in which a concrete slab is prepared and then used as a foundation. Here, a 4-8 thick concrete slab is made on an initially prepared frost line footing then used as a base for the entire building. In this situation, the foundation is directly constructed on a place in which there is no crawlspace or basement. However, for slab foundation to be effective, it needs to be embedded with steel bars (Dearborn & Verton, 2007). These are necessary for preventing any faulting or cracking which might be experienced. Besides, it should be made after the construction of all the necessary waistlines and waterlines. Thus, it will produce a very firm and long lasting foundation for the structure. Slab foundation has become very popular with many interior designers because it is less costly. In fact, it is the cheapest of all the construction foundations. Unlike other foundations, it only requires the use of a slab. This helps in saving on the money that would otherwise be used in floor joints that are used for supporting the building. In addition, the construction of this foundation is much easier as compared to others. Once it is made, the house is directly erected on it (Nicholson, 2011). Hence, it helps in saving a lot of time during the construction process. Nevertheless, slab foundation might be undesirable to some designers and house owners because it is more expensive to maintain. For example, in case of any breakage, the entire slab might be torn a part before any reparations are made. Meaning, it is expensive to repair in case of damage. Crawlspace foundation is constructed from the outside of the house. They are raised above the ground to elevate the building to around 5 feet above the ground level. It is

The value of brands to organizations Essay Example | Topics and Well Written Essays - 1750 words - 1

The value of brands to organizations - Essay Example establish the aforementioned by elucidating on the value of brands through a definition of the concept, an analysis of the implications of brand equity, a discussion of the benefits of brands and a clarification of the relationship between brands and firms. Brands are firm-owned products which have undergone a process of branding. It is â€Å"the means by which a company aims to differentiate its products from competition and-through marketing-protect its position in the market. profitably over time† (White 1999) It is recognized as â€Å"the sum of ail elements of the marketing mix† (Ambler and Styles 1996). The most commonly accepted definition of brand is a distinguishing name and/or symbol (such as a logo. trademark or package design) intended to identify the goods or services of either one seller or a group of sellers and to differentiate those goods or services from those of competitors (Aaker 1991. p. 7). Other relevant brand concepts include brand associations, brand image, brand identity and brand equity. Brand associations are â€Å"anything that connects the customer to the brand.† They include â€Å"user imagery, product attributes, use situations, organizational associations, brand personality, and symbols† (Aaker and Joachimathaler 2000. p. 17). Brand strategies, the set of â€Å"perceptions about a brand as reflected by the brand associations held in consumer memory† (Herzog 1963). Brand identity is defined as the totality of the brand associations that the marketer wishes to create or maintain for the brand: Brand identity is a unique set of brand associations that the brand strategist aspires to create or maintain, These associations represent that the brand stands for and imply a promise to customers for the organisation members (Aaker, 1996, p. 68) It represents â€Å"what the organization wants the brand to stand for† (Aaker and Joachimathaler 2000. p. 40). Brand identity is thus contrasted to brand image, where brand image is a

Physics Behind the Dambuster’s Bouncing Bomb

Physics Behind the Dambuster’s Bouncing Bomb Brookie Trant Introduction The Dambuster Raid and the bouncing bomb played a key role in WW2. The aim was to disrupt industrial productivity of Germany. The Raid was also a well-publicised success story when Britain was stretched to breaking point during the war. The bomb was used to destroy the Mohne and the Edersee Dams and flood the Ruhr Valley, thereby destroying a large proportion of the Germans manufacturing power; thus having the desired knock on effects for the German war effort. The bomb was initially conceived by Dr Barnes Wallis in April 1942 in a paper he wrote called ‘spherical bomb – surface torpedo’[1]. The concept was then taken up by Air Chief Marshal the Hon Sir Ralph Cochrane of the Royal Air Force a strong advocate of precision bombing. Also important to bringing the concept to fruition was Air Marshal Arthur Harris commander of Bomber Command. Through these influential commanders Wallis’ idea was brought to a committee and it given the go ahead. Wallis faced a range of practical issues such as: the size-to-weight ratio of the bomb with the ability of the aircraft to physically lift and deliver it; how much backspin was needed to be imparted to the bomb in order for it to have a controlled and accurate flight; speed of flight; height from which to drop it and the velocity of the aircraft at point of delivery. All these factors needed to be understood and overcome in order that the bomb could be delivered to the optimum point on the dam wall and then detonated. In answering this question this study will consider four key factors: the weapon design, the delivery of the weapon, the detonation and how all of these had a great enough affect to destroy the dam. It is useful at this point to qualify the definition of the bouncing bomb. The use of bouncing to describe the Operation Chastise bomb is loose. The physics of bouncing by definition requires a level of elasticity which as the object hits a solid, a fluid or a powder results in a permanent or non-permanent change in the objects form (elasticity). This doesn’t occur with the ‘bouncing’ bomb. It is better to define the Chastise Bomb as ricocheting but for the purpose of this study the phrase bouncing bomb will be used[2]. Weapon Design This was where the bomb started. A key area which needed to be addressed was the shape of the bomb. This had a major role in providing a reliable and successful bomb. This section explains the reasoning behind the cylindrical shape and how this affected the bombs delivery. The shape of the bomb was a key issue. Wallis’ initial trials used spherical models, so that identical contact with the water would be made throughout its flight; however the bounces were often too unpredictable due to release and water surface conditions. Therefore, to achieve greater stability Wallis experimented with a cylindrical bomb. This negated the unpredictability but did not stabilise the issues of trajectory and keeping it level. He realised that by using backspin these problems could be overcome. Backspin was also a key aspect in the delivery of the weapon to the detonation point. This vital aspect will be further discussed in this study in the delivery method section. Once at the point of detonation the bomb was required to explode underwater. On explosion a shock wave would be created, enough to destabilise the dam wall. The weight of water would then provide the breach. Wallis started with trying to find the correct measurements for the amount of explosive needed to breech the dam. He used a model on a scale of 1/17 of the real thing. He then used 100g of gelignite 1.2m away from the wall giving the same effect as a 10 tonne bomb 60m away from the dam. This had no effect. He continued his trials until he achieved 150g of explosive 0.3m away from the dam, which meant that he had to use 13 tonnes of explosive 15m away from the dam. When scaled back up, this would need 18 tonnes of casing which would give a 31 tonne bomb to match the effect required. This was a significantly larger bomb that could be dropped by the aircraft to be used. It was clear that he would have to find a different method. He reduced the mass to 4.3 tonnes and would use multip le bombs to breech the dam[3]. The final dimensions of the bomb were 60 inches long and 50 inches wide[4]. This is roughly 1.52m in length and 1.27m in width, with a final weight of 9,250[5]. See figure 1. Delivery Method His next problem was working out speed of the bombs, how far above the surface they needed to be dropped, the distance from the dam and the best way to control the skips of the bomb. His first trials were conducted in his garden at home. He fired marbles across a bucket of water to see whether it would bounce off the surface. It worked and he could control the skip by adjusting the catapult. He now needed to discover if he could control the bomb when it was using multiple skips. For this he needed a slightly larger apparatus and used a huge ship tank at Teddington. Starting with a spherical bomb, he tested different size-to-weight ratios and by using backspin he could control the bounces. This also helped the bomb to sink in a predictable manner when it reached the wall. Here he had success, however Wallis found the flight of the bomb was often unpredictable. He found if he increased the mass significantly it became more stable however for reasons already stated a larger bomb was impractical. Wallis had realised that stability could be achieved by using a cylindrical casing and imparting backspin. This would keep the barrel on its axis and stop it from tilting and therefore follow its correct trajectory. Much like a child’s spinning-top toy, the more backspin you gave the bomb the harder it would be to knock it off its axis, this is angular momentum (this is explained in the paragraph below). He tested the idea in the tank trying out the different revolutions. He also found that by varying the size-to-weight ratio of the cylinders he could keep a 5 ton barrel level on the water and then get it to spin down the dam once it hit the water[6]. Also by rapidly spinning the device backwards this would counteract the forward velocity of the aircraft. Wallis calculated how many bounces would be required before reaching the dam. This calculation needed to include the drop distance from the dam, the elevation of the aircraft and its forward velocity. Importantly with each bo unce the bomb would slow due to the viscosity of the water and the drag effect that it had. Using this equation Wallis was able to calculate the speed of the spin to ensure that the bomb had slowed down to almost zero velocity by the time it reached the dam[7]. He measured that the cylinder would need to be going at 450 to 500 revolutions per minute2 in order to achieve this effect. Angular momentum has the same role as linear momentum but in rotation. The equation for angular momentum is. The equation for linear momentum is â€Å"†. In the equation for angular momentum the ‘I’ replaces the ‘m’ and the ‘ω’ replaces the ‘v’. The ‘I’ is the moment of inertia which is an objects reluctance to change its state of rotational motion[8]. The equation for the moment of inertia changes with the different shapes it is acting on. For a cylinder the moment of inertia is. This meant that by increasing the mass and the radius the moment of inertia will increase making it more stable. However Wallis was restricted by the size of the planes and their ability to carry a heavy bomb. So he used the largest diameter as possible and then put the majority of the weight of the bomb as close to the edge of the cylinder as possible. This way it would have the same effect as a flywheel giving the barrel lots of m omentum. The ‘ω’ is the angular velocity which is how quick the cylinder is rotating its unit is rad s-1. The equation for ω is which shows as you increase the frequency then the ω will increase by a considerable amount. When you put the moment of inertia and angular velocity together you get the angular momentum of a rotating object. It also shows you that by increasing the angular velocity makes it much more difficult to knock the barrel off its axis. Going back to the spinning top the faster you spin it the more difficult it becomes to knock it over. This is what gave the bouncing bomb a clean flight and made sure that it remained on course and didn’t tilt off its axis. The backspin had a secondary effect. By dropping the bomb without backspin the device would naturally receive a turning effect through the horizontal axis in the opposite direction; the net result of this would be that the bomb would not slow in a uniform or predictable manner and therefore likely skip out over the dam rather than slowing and dropping down the inside face. Forward spinning the bomb would have a similar effect to that experienced by a bicycle wheel being rolled at a curb. It wants to keep going[9]. There is a third effect achieved by imparting backspin. This is the key relationship that Wallis would have been aware of and used to calculate speed, height and turning effect. This effect is the Kuttas Lift Theorem or the Kutta–Joukowski Theorem. Developed by German Martin Wihelm Kutta and Russian Nikolai Zhukovsky (Joukowski), in the early twentieth century, the theorem demonstrates the aerodynamic relationship between lift, speed of a rotating cylinder and density of the substance it is moving through (air or fluid)[10]. This theorem sometimes known as the Magnus effect when applied to the conditions of the Dam Buster raid allowed the bomb to ‘crawl’ down the face of the dam wall. The water surrounding the cylinder in conjunction with the back rotation caused striking hydrodynamic forces that pulled the bomb back towards the wall[11]. As seen in figure 2. All three of these effects were identified, quantified, understood and overcome by Wallis, through his thorough trials and experiments and his deep knowledge of physics. Detonation Mechanism The aim of Operation Chastise was to blow up the dam; the easiest way to do this would be to blow the explosive charge on the water side of the dam at the optimum depth. This would make the most of the explosive power. With the weight of the water behind the explosion, it would increase the affect of the force of the bomb. This weight would pressure the dam to breaking through whatever weaknesses had been caused by the initial force of the bomb. The bomb contained three hydrostatic pistols which measured the water pressure as the bomb sank, the bomb would then detonate at a depth of 30 feet. It also had a time fuse that would detonate after 90 seconds as a backup. This was reasonably well developed technology drawn from the experiences of the First World War naval fighting and the ongoing anti-submarine war effort. In essence the hydrostatic pressure, used in the hydrodynamic pistol, increases uniformly according to the simplified equation of P = p g h (where P is hydrostatic pressur e, p is the fluid density (kg/m3), g is gravity and h is height of the water)[12]; the change in the hydrostatic pressure would trigger the hydrodynamic pistol to explode at a depth of 30 feet (9.14m)[13]. Target Effect Once delivered to the detonation point against the dam wall at the correct depth the weapon exploded. This maximised the benefits of the bubble pulse effect typical of underwater explosions, greatly increasing its effectiveness of the explosion and the pressure. The dam wasn’t going to fall by just using the explosive power of the TNT and RDX applied to the external wall of the dam, but by using the pressure of 30 foot (9.14m) of water pressing down on the explosion. The initial force exerted by the exploding bomb was meant to weaken the dam; the water would do the rest. Compared to air water has a significantly higher density than air. Water has a higher quotient of inertia than air. Although this makes water more difficult to move it does mean that it is an excellent conductor of shock waves from an explosion. The damage achieved by these shock waves will be amplified by the subsequent physical movement of water and by the repeated secondary shockwaves or â€Å"bubble pulse †[14]. The small seemingly insignificant cracks formed by the bomb would then be exploited by the water forcing the gaps to get larger until the point where the dam couldn’t hold it any longer. The dam then crumbled. The equation for pressure is (P=pressure, F=force, A=area) this can be rearranged to give this shows us that the pressure will make a huge difference to the force of the explosion. Summary In summarising this study of the physics behind the dam buster raid it is important to recognise the breadth of Barnes Wallis’s experimentation and trials. He overcame the issues of weapon design: its explosive effect and detonation method and issues of casing; the delivery method in terms of speed, height and skip effect; the detonation method; and then the weapon effect on the target. A clear understanding physics and a deep understanding of fluid mechanics, hydrodynamic pressure and the crucial consequence of Magnus Effect were essential for Wallis’s concept to succeed. Bibliography 1 http://en.wikipedia.org/wiki/Bouncing_bomb I used wikipedia just to gain some background knowledge and to use in my introduction. 2 Johnson, W. (1998). Ricochet of non-spinning projectiles, mainly from water Part I: Some historical contributions. International Journal of Impact Engineering (UK: Elsevier) – this was from the same Wikipedia page but the extract was taken from this paper written by W. Johnson. 3 http://home.cc.umanitoba.ca/~stinner/stinner/pdfs/1989-dambusters.pdf this is another paper on the bouncing bomb providing information on the facts and figures on the bomb 4 http://everything2.com/title/bouncing+bomb again this is just facts about the bouncing bomb itself 5 http://www.rafmuseum.org.uk/research/online-exhibitions/617-squadron-and-the-dams-raid/designing-the-upkeep-mine.aspx another with facts an about the bombs dimensions and weight ect. 6 http://simscience.org/fluid/red/DamBusters.html this is a paper for those doing a-level so has very relevant information on it and is a reliable source 7 http://wiki.answers.com/Q/Why_did_Barnes_Wallace_decide_to_spin_the_dambusters_bomb_backwards#slide=16article=Why_did_Barnes_Wallace_decide_to_spin_the_dambusters_bomb_backwards this is using Wikipedia again but it is a general statement so not needing a confirmation reference 8 Advanced Physics (p.101/105) – this is a book used in the physics a-level it gives a great level of understanding and was a very useful book when wanting to look beyond the syllabus 9 A.M. Kuethe and J.D. Schetzer (1959), Foundations of Aerodynamics, John Wiley Sons, Inc., New York ISBN 0-471-50952-3. – this is a book and it explains basic aerodynamics which can also be related to the forces acting on an object in fluid which is the context used in this essay 10 http://www.britannica.com/EBchecked/topic/357684/Magnus-effect this briefly explains the Magnus effect which is used when the bomb is trying to sink down the dam face 11 Pascal’s law – found on http://www.engineeringtoolbox.com/pascal-laws-d_1274.html 12 http://www.historylearningsite.co.uk/dambusters.htm information about the bomb. 13 Fox, Robert; McDonald, Alan; Pritchard, Philip (2012). Fluid Mechanics (8 ed.). John Wiley Sons – another book used briefly to explain how the bomb created a large enough force to break the dam. [1] http://en.wikipedia.org/wiki/Bouncing_bomb [2] Johnson, W. (1998). Ricochet of non-spinning projectiles, mainly from water Part I: Some historical contributions. International Journal of Impact Engineering (UK: Elsevier) [3] http://home.cc.umanitoba.ca/~stinner/stinner/pdfs/1989-dambusters.pdf [4] http://everything2.com/title/bouncing+bomb [5] http://www.rafmuseum.org.uk/research/online-exhibitions/617-squadron-and-the-dams-raid/designing-the-upkeep-mine.aspx [6] http://simscience.org/fluid/red/DamBusters.html [7]http://wiki.answers.com/Q/Why_did_Barnes_Wallace_decide_to_spin_the_dambusters_bomb_backwards#slide=16article=Why_did_Barnes_Wallace_decide_to_spin_the_dambusters_bomb_backwards [8] Advanced Physics (p.101) [9]http://wiki.answers.com/Q/Why_did_Barnes_Wallace_decide_to_spin_the_dambusters_bomb_backwards#slide=16article=Why_did_Barnes_Wallace_decide_to_spin_the_dambusters_bomb_backwards [10] A.M. Kuethe and J.D. Schetzer (1959), Foundations of Aerodynamics, John Wiley Sons, Inc., New York ISBN 0-471-50952-3. [11] http://www.britannica.com/EBchecked/topic/357684/Magnus-effect [12] Pascal’s law [13] http://www.historylearningsite.co.uk/dambusters.htm [14]Fox, Robert; McDonald, Alan; Pritchard, Philip (2012). Fluid Mechanics (8 ed.). John Wiley Sons.

The Relevance of Ancient Texts in Today’s Society Essay examples -- Li

Ancient texts are utilized as guides and references for the people of today. Some people live by their rules, laws, and stories and truly take them to heart. Many of these texts have been read and interpreted by students, historians, and professors all around the world for many generations. Three specific texts, the Tanakh, Sophocles’ Antigone, and Plato’s Apology, are all examples that have been analyzed and discussed for many years. There are key concepts in each of these works that are still relevant in society today and some that should be left in the past. The Tanakh provides the groundwork for the Jewish/Hebrew religion from the third century BCE (Trulove, Woelfel, Aauerbach, & Buller, 2007). One centralized theme discussed in the Tanakh is going against a higher power. In Genesis, God told Adam and Eve â€Å"‘you shall not eat of [the tree of the knowledge of good and evil] or touch it, lest you die’† (Trulove et al., 2007, p. 40). Adam and Eve chose to consume a piece of fruit from the tree; as a consequence, God banished them from the Garden of Eden (Trulove et al., 2007). As a result of their sin, the world became corrupt and â€Å"filled with lawlessness† (Trulove et al., 2007, p. 43). In these instances, the higher power was the people’s God. When they disobeyed him, they suffered the consequences. These consequences were more severe since a divine power was in charge. Similarly, in Exodus, the Pharaoh â€Å"set taskmasters over [the Israelites] to oppress them into forced labor† (Trulov e et al., 2007, p. 58). The Pharaoh established rules and punishments for the taskmasters to bestow on the Israelites. In this situation, the higher power was the ruler of the land. The Israelites not only had to follow the laws set forth by the Pha... ...the sky and below the earth† instead of the god that the state permitted people to worship. People in every country, not just the United States, should be free to worship however they choose. Fortunately, in the United States, our Constitution prevents the government from controlling our religious freedoms. In summary, even though ancient texts are looked to as reference, they should not always be taken literally. Some concepts, including gender roles, government-appointed religions, and covenants with God, need to or have already been done away with. On the other hand, the determination to do what is morally and legally proper must continue to be an integral part of modern society. People should examine these ancient works, analyze how different civilizations dealt with success as well as conflict, and try to incorporate the lessons learned in their own lives.

Political science as a social science Essay

Political Science is in part a social science, and in part a humanity. Both are important. In this topic, we will look at the basics of social science inquiry, and then proceed to show how this differs from, on the one hand, inquiry in the natural sciences and, on the other, inquiry in the humanities. Social Science Social science inquiry seeks to develop empirical theory. ?Empirical? refers to things that can be experienced through the five senses of seeing, hearing, touching, tasting, or (in the case of political corruption) smelling. Theory? basically means explanation. An empirical theory of politics, then, is an attempt to explain why people behave the way they do politically. If a social scientist (or anyone else) observes people engaging in political behavior, he or she will need to focus on certain characteristics of the people being observed. The observer may wonder why some people differ from others in their political characteristics. Why, for example, are some people Liberals while others are Conservatives and still others are New Democrats. Characteristics that differ from one person to another are called one variables. Those that do not are called constants. Constants are generally less interesting than variables. There is not much point in trying to explain voting behavior in a country in which only one party appears on the ballot. Of course, we might then ask why some countries have only one party whereas others have multi-party systems, but now we are treating ? number of parties? as a variables. Everyday language is full of what are, in effect, hypotheses about political behavior. For example, talk about a ? gender gap? in voting hypothesizes that vote (the dependent variable) is in part a function of gender (the independent variable), with women more likely to vote for the Liberals or New Democrats and men more likely to vote Conservative. Social science research differs from everyday discussion of politics in two ways. The first is where hypotheses come from. Anyone who follows politics will likely carry around in his or her head a lot of ideas about what explains political behavior. Such ideas may come from personal experience, from conversations with others, or from following politics through the mass media. This is true as well for the ways social scientists think about politics. In addition, however, social scientists develop hypotheses more systematically by studying the scholarly literature for the results of previous research. This is important for at least a couple of reasons. For one thing, it is usually the case that the more you learn what is already known about a subject, the more new questions you are likely to have. A review of the literature helps generate new hypotheses. Even more important, social science seeks not merely to describe raw facts, but to explain why people behave the way that they do. To accomplish this, we need to put our ideas into a broader theoretical context that offers such an explanation. It is a fact that in the United States, from 1936 through 2000, the incumbent party has always won the presidency whenever the Washington Redskins won their last home game before the election, and lost whenever the Redskins lost. However, since there is no reasonable explanation for why this should be the case, it is merely an interesting bit of trivia, and no serious observer of politics would rely on it in analyzing the next presidential contest. A second difference is that, for many people, ideas about patterns of political behavior remain merely assumptions. Social science insists that the validity of assumptions must be tested against data. Conceptual definition. We need to know, and be able to communicate to others, what our independent and dependent variables mean. What, in other words, is the idea in our mind when we use a term? Definitions found in dictionaries are examples of conceptual definitions. Sometimes, the idea that is in our mind when we use a term will be obvious, but often it will not. Many concepts used in political science are anything but clear. If we are to study political ideology, for example, we need to spell out with as much precision as possible what that concept means in the context of our research. Operational definition. For hypotheses to be tested, we will need to come up with measurements of our variables. An operational definition is one stated in a way that can be directly measured by data. We strive for a one-to-one correspondence between our conceptual definitions and our measurements (operational definitions) of them. If we succeed, then our measurements have validity and reliability. Data needed to provide operational definitions of our variables come from a wide variety of sources. We may gather the data ourselves. Analysis of data that we gather in order to test hypotheses that we have formulated is called primary analysis. Often, however, this approach would be totally beyond our resources of time, money, and expertise. A nationwide survey of public opinion, for example, would take months to design and carry out, would cost many thousands of dollars, and would require the services of a large survey research organization. Often, secondary analysis of data (that is, analysis of data originally gathered for other purposes) will suit our needs far better. Indeed, very important databases are used almost exclusively in secondary analysis. The Census Canada data is a good example. Other surveys such as the Canadian National Election Study and the General Social Survey were created, in part, for the express purpose of providing quality survey data for secondary analysis by students of Canadian politics. Indeed much of the work using the Canadian National is based on secondary analysis. To facilitate secondary analysis, the University of Toronto Data Library, and other university-based data archives have been established throughout the world. The largest of these is the Inter-university Consortium for Political and Social Research (ICPSR) established in 1962. Today, over 500 colleges and universities from all over the world, including the University of Toronto are member institutions. Students and faculty at these institutions obtain datasets that provide the basis for numerous scholarly books, articles, and conference papers, graduate theses and dissertations, and undergraduate term papers. The Social Sciences and the Natural Sciences What we have described as the social science method ? the effort to explain empirical phenomena by developing and testing hypotheses ? could as easily be called simply ? the scientific method,? without the ?  social? qualifier. There are, however, differences between social sciences, including political science, and the natural sciences. Though these are differences in degree, they are important. One difference is that the natural sciences rely much more heavily on experimental design, in which subjects are assigned randomly to groups and in which the researcher is able to manipulate the independent varia ble in order to measure its impact on the dependent variable. Often, when people think about the scientific method, what they have in mind are these sorts of controlled laboratory experiments. In political science, we for the most part are not able to carry out experimental designs. If, for example, we wish to study the impact of party affiliation on decisions by judges, we cannot very well assign judges to different parties, but rather have to take the data as they come to us from observing judges in their natural setting. Experimental design, however, does not define the natural sciences, nor does its absence define the social sciences. Astronomy, for example, must of necessity rely on observation of things that cannot be manipulated. ?Epidemiological?  medical research also relies on non-experimental data. Conversely, the social science discipline of social psychology has been built in large part from experiments in small group laboratories. In political science, a great deal of laboratory research on the impact of campaign commercials has been carried out in recent years. Field experiments are also common, as when survey researchers will test the impact of alternativ e question wordings by splitting their sample and administering different questionnaire forms to different subsets of respondents. Nevertheless, it is fair to say that experimental designs are much less common in the social sciences, including political science, than in the natural sciences. Most of our research design is, in effect, an effort to approximate the logic of experimental design as closely as possible. Other differences, also differences in degree, have to do with lower levels of consensus in the social sciences. There is less consensus about conceptual definition. Even if we agree that power is a key concept for the study of politics, we may not agree on what power means. Chemists, on the other hand, not only agree that molecules are important, they also mean pretty much the same thing when they use the term. There is less consensus about operational definition. Chemists also agree on how to measure the atomic weight of a molecule. Social scientists are far from unanimous in the ways they go about measuring power. It bears repeating that these differences are ones of degree. In the natural sciences there are also disputes at the frontiers of the various disciplines about what concepts are important, what they mean, and how they should be measured. In the social sciences, consensus is likely to break down from the start. Even if we can agree that a particular concept is important, on what it means, and on how it should be measured, we will encounter far larger problems of measurement error than those in the natural sciences, where measurement is not without error, but is typically much more precise. Finally, remember that we are involved in trying to explain human behavior. People do not seem to behave as predictably as molecules. Philosophers are not in agreement on this point, but it may be that human behavior is inherently less predictabl The fact that we deal with tendencies rather than with laws means that, for the most part (and despite impressive work by ? rational choice? theorists to develop formal mathematical models of political behavior), political science makes relatively little use of elegant systems of deduction, but considerable use of statistics, which provides us with valuable tools for dealing with probabilities. Despite its unavoidable limitations, political science as a social science has produced an explosion in our knowledge about politics. This has had important practical consequences. For example, no serious aspirant for a major elected office in an economically developed democracy would consider embarking on a campaign without consulting experts in survey research, a signature social science technique. In addition to being, in part, a social science, political science is also in part a humanity. Political science as a humanity means at least a couple of different things.

Effect of extracurricular activities on the gpa

An example of this would be a varsity player who has training in the afternoon till evening, then goes home with the notion that he still has to do an immense amount of paper work due the following morning. Furthermore, Roland, a professional writer, graduate of B. S. En may also pull his grades down if he becomes too engrossed [Emphasis mine] with other activities. This all boils down to the fact that poor time management will be the main downfall of an individual's academic performance. At this point, the question to ask is what's in it for one's character formation? Well, the experts have some points on this matter. First, McNealy summarizes that these activities actually are conducive to facilitate effective communication [Emphasis mine] (Francisco) because an individual is put in a situation wherein interaction is a just.To illustrate this point, there is no such thing as a theatre actor who cannot communicate with his fellow actors, much more to the audience. He cannot be calle d one if he does not exemplify this trait. Second, confidence [Emphasis mine] is also attained through the process of the venture (Francisco) Nominal 3 for the same reason that one is put in this situation wherein bravery must be exercised with the help of this so called confidence. Again to compare it with an actor, one must be able to deliver his lines with absolutely no evidence of fear while he is carrying the weight of a performance.These two points presented are further strengthened by † [a] 2001 survey of more than 50,000 high school students in Minnesota published in March 2003 issue of the Journal of School Health found that those who participated in extracurricular activities had higher [Emphasis mine] levels of social, emotional, and healthy behavior than students who did not participate (Francisco). † Altogether these findings indicate that confidence and communication skills, two of the many, are integral to building one's character through extracurricular a ctivities as backed up by the prior evidence that are found inFranciscans research. On the other hand, there are also a few drawbacks or cons when it comes to character formation when one considers other miscellaneous influences. One would be the parents' influence wherein they'd force an individual to learn this certain activity but that task isn't to his liking, thus, all the more he is stressed [Emphasis mine] out (Roland). According to Frederick's, another drawback would be the unavoidable internal influences that one may encounter such as malicious authorities and peers who will force him to do harmful vices and delinquent actions (Francisco).What's more is that the people who are participating in the extracurricular activity may actually be the one bringing themselves down for neglect of their other obligations like family, friends, etc. Without a doubt it would be disastrous if they were to treat their extra undertakings as their own vices. Finally, these findings would certa inly be mainly dependent in the kind of educational context one is in. In conclusion, after all the facts have been presented, it all depends on an individual's choice whether or not he chooses to Join and bestow upon himself the benefits and pay a price or stay free with little or no improvement.

Applications of fluorescent protein-based biosensors for the elucidation of protein function within cells Essays

Applications of fluorescent protein-based biosensors for the elucidation of protein function within cells Essays Applications of fluorescent protein-based biosensors for the elucidation of protein function within cells Essay Applications of fluorescent protein-based biosensors for the elucidation of protein function within cells Essay Biosensors are used for sensing of an analyte ( e.g. a little molecule, a protein, or an enzymatic activity ) and its interaction with a molecular acknowledgment component, MRE ( e.g. a protein sphere ) . It consists of 3 parts ; the sensitive biological component, the transducer or sensor component ( which transforms the signal resulting from the interaction into another signal that can be more easy measured and quantified ) , and signal processors ( show consequences ) . Biorecognition processes require biosensors to hold the ability to transduce an event into an discernible alteration e.g. coloring material or fluorescence hue i.e. an effectual transducer component. A alteration frequently attach toing an event is an change of the geometry of the MRE ( distance alteration between the MRE and its analyte protein-protein interaction, or a conformational alteration of the MRE allosteric proteins ) . In recent old ages, biochemists adapted the term biosensor to mention to genetically encoded designed proteins that are self-sufficing sensing systems for a figure of marks. The chief difference between conventional biosensors and genetically encoded biosensors is the nature of the transducer. Conventionally, a transducer is a man-made and modified surface that is electrochemically or optically sensitive to the action of the biomolecule. In contrast, the pick of transducer for a genetically encoded biosensor is constrained to being genetically encoded ( 1 ) . Aequorea green fluorescent protein ( FP ) and its discrepancies are a critical constituent of genetically encoded biosensors. The scope of FP-based biosensors which include different designs can be used by research workers to supervise alterations in the geometry of an MRE through the assorted features of the FPs e.g. transition of the fluorescence chromaticity or strength of an intrinsically fluorescent protein. The usage of genetically encoded FP-based biosensors offers several advantages compared to other techniques ( such as dye-based investigations ) . They are comparatively easy to build utilizing standard molecular biological science techniques and can be used to analyze protein localization of function and kineticss within life cells. The latter occurs through the non-invasive debut of these biosensors into cells ( they are produced utilizing cellular machinery ) where they can obtain information of specific biochemical and biorecognition procedures from any one of a broad scope of cellular compartments without interfering with the interaction ( 2 ) . All genetically encoded FP-based biosensors can be assembled into the undermentioned 5 groups depending on their construction: * Group 1 intramolecular FRET-based biosensors * Group 2 intermolecular FRET-based biosensors * Group 3 BiFC-based biosensors * Group 4 individual FP-based biosensors with an exogenic MRE * Group 5 individual FP-based biosensors with an endogenous MRE Group 1 biosensors are based on intramolecular Forster Resonance Energy Transfer ( FRET ) . FRET is the distance- and orientation-dependent nonradiative transportation of internal energy from a higher-energy giver fluorophore to a lower-energy acceptor fluorophore through dipole-dipole yoke. FRET-based biosensors have all of their constituents on a individual polypeptide concatenation ( two FPs flanking an MRE ) and the analyte brings about a alteration in the construction or conformation of the MRE unit ( see Fig 1 ) . Modulating the distance or comparative orientations between the fluorophores affects the FRET efficiency, which is revealed by the acceptor ( IA ) /donor ( ID ) emanation ratio i.e. an addition in IA at the disbursal of ID. FRET occurs about outright and is reversible, therefore supplying better declaration than the BiFC method ( discussed subsequently ) ( 3 ) . Application of this biosensor design includes sensing of proteolytic activities. An MRE consisting of a polypeptide that is a substrate for the peptidase under probe is used to observe proteolytic activity. Tsai MT et Al ( 4 ) late carried out a survey to supervise intracellular human enterovirus ( HEV ) peptidase activity by utilizing a HEV 3C peptidase FRET-based biosensor. They found that this system was a agency for rapid sensing, quantification and drug susceptibleness proving for HEVs. FRET-based biosensors can besides be used to observe post-translational alteration ( PTM ) enzymes activities. An MRE with the ability to observe PTM enzyme activity ( catalyses the covalent alteration of a substrate ) is composed of a specific substrate and a binding sphere. The MRE so undergoes geometry alterations in response to PTM activity. This attack was late used to observe ERK ( kinase enzyme ) activity. EKAR, a genetically encoded FRET-based detector of ERK activity was designed and te sted. EKAR selectively and reversibly reported ERK activity after EGF stimulation in HEK293 cells, leting for the analysis of ERK signalling in life cells ( 5 ) . A 3rd application of this design is to observe MRE conformational alterations triggered by the presence of its analyte. Some proteins e.g. bacterial periplasmic binding proteins ( 6 ) undergo such a alteration. Consequently, they have been used to do FRET based biosensors for analytes such as glucose, Ca2+ and Zn2+ . Group 2 includes biosensors based on intermolecular FRET. The two FPs are in two different polypeptide ironss ( the MRE is fused to one FP and the analyte protein is fused to another ) and are brought closer together by a protein-protein interaction ( see Fig 2 ) . This design has been used to analyze the oligomerisation province of different members of the G-protein-coupled-receptor ( GPCR ) superfamily. It has besides been used to analyze mGluR1 activation. Marcaggi P et Al ( 7 ) employed the FRET phenomenon to analyze the activation dynamicss of mGluR1. The writers show that the alterations in FRET correlative with activation of the receptor. Care must be taken when construing intermolecular FRET consequences, since FRET may perchance happen between two proteins that show no interactions straight. There may besides be fluctuation in the look degree of the two halves of the biosensor. This is of peculiar concern when ratiometric measurings are taken. Group 3 biosensors, bimolecular fluorescence complementation ( BiFC ) , enable direct visual image of protein interactions in life cells. The BiFC attack is based on the reconstitution of a fluorescent composite when two proteins ( MRE and analyte ) , fused to non-fluorescent fragments of a fluorescent protein, interact with each other. The interaction between the merger proteins facilitates the association between the fragments of the fluorescent protein ( see Fig 3 ) . This attack enables visual image of a assortment of protein-protein interactions in the normal cellular environment. BiFC composites have been visualized in all major subcellular compartments of mammalian cells, including lysosomes, the plasma membrane, lamellipodia, Golgi, the endoplasmic Reticulum, chondriosome, viral atoms, and lipid droplets. It has provided particular penetration into the ordinance of complex localization of function including atomic translocation ( 8 ) . It has besides been used in a survey of the grippe A polymerase composite to find the interaction between its 3 fractional monetary units ( PA, PB1 and PB2 ) required for the written text and reproduction of the viral genome. It revealed a antecedently unknown PA-PB2 interaction and provided a model for farther probe of the biological relevancy of the PA-PB2 interaction in the polymerase activity and viral reproduction of grippe A virus ( 9 ) . A motley BiFC check may besides be used for coincident imagination of more than one event in unrecorded cells. This check is based on the formation of fluorescent composites with diffe rent spectra through the association of fragments belonging to different FPs, making Chimeras with a assortment of fluorescent chromaticities ( see Fig 4 ) . This technique was used in a survey to look into the oligomerization province of adenosine A ( 2A ) and dopamine D2 GPCRs found to be ligand-dependent, and besides how they were affected by the presence of certain drugs ( 10 ) . A restriction of the BiFC attack is that there is a hold ( dependent on the sensitiveness of the sensing method ) between the clip when the merger proteins interact with each other and the clip when the complex becomes fluorescent. This is due to the slow rate of the chemical reactions required to bring forth the fluorophore. Therefore, an advantage of FRET over BiFC analysis is that real-time sensing of complex formation and dissociation is possible. Group 4 biosensors use an exogenic MRE inserted into a individual FP at certain locations. Information about the birecognition event from the MRE is carried to the chromophore altering its spectral belongingss ( see Fig 5 ) . A biosensor with this design was used in a recent survey by Berg J et Al ( 11 ) . The detector was constructed by uniting cmpVenus ( a circularly permuted discrepancy of green fluorescent protein ) with a bacterial regulative protein ; GlnK1 ( used an ATP specific MRE ) . Binding of ATP caused conformational alterations in GlnK1 protein which ratiometrically changed the excitement profile of cmpVenus. Initially, the purpose was to find the ATP concentration. However, as ADP binds to the same site ( bring forthing a smaller alteration in fluorescence than ATP ) , competition between the two substrates made the detector more suited for ratiometric measuring of ATP: ADP concentration ratio by excitation. , in unrecorded cells. This is a all right illustration of tuning and optimizing biosensors. The same design has been used for Ca2+ , Zn2+ and cGMP sensing in other surveies. Group 5 biosensors besides use a individual FP but with an endogenous MRE. An illustration of this design is a redox-sensitive GFP ( roGFP ) . By permutation of two surface-exposed residues on the Aequorea Victoria green fluorescent protein with cysteines in appropriate places to organize disulfide bonds, redox-sensitive GFPs ( roGFPs ) were created, which allowed for ratiometric measuring of the cell oxidation-reduction position ( 12 ) . This theoretical account has late been improved through merger of roGFP to human glutaredoxin-1 ( Glx1 ) , which catalyses rapid equilibration between roGFP and glutathione, bettering the response rate of roGFP ( 13 ) . Most FP discrepancies show pH-dependent alteration in their spectral belongingss, which consequences in a alteration in their fluorescence strength. This makes measurings hard to graduate. To get the better of this restriction, the pH-dependent alterations in EGFP ( an engineered avGFP discrepancy ) fluorescence life-time have late been imaged, instead than strength, as the former does non depend on fluorophore concentration ( 14 ) . It must be noted that some designs do non suit the 5 chief classs. Esposito et Al ( 15 ) displayed an interesting illustration of FRET-based pH biosensor that is composed of a pH-insensitive giver fluorophore and a pH-sensitive acceptor fluorophore. Unlike the conventional FRET-based biosensors that depend on the alterations in comparative distance and/or orientation of the fluorophores, this biosensor depends on the spectral alterations of the acceptor fluorophore that accompany pH alterations which in bend change the overlap built-in impacting FRET. Decision As research continues, life scientists will look to engineer a complete set of biosensors that are specifically tuned to the conditions of the event under probe. In add-on to building new biosensors, it is of import to go on bettering the specificity of the current theoretical accounts. This may even happen through incidental findings such as that found in the survey by Berg J et Al, which looked ab initio at ATP concentration but subsequently found that the biosensor was a better index of the ATP: ADP concentration ratio ( see above ) . Another avenue which can be explored is the monitoring of more than one cellular event through a combination of different types of biosensors. An interesting illustration of this is a survey by Ai H W et Al ( 16 ) which looks at observing caspase-3 activity in the cytol and nucleus utilizing two FRET braces at the same time. This survey shows how the usage of this brace preserved the temporal declaration of the caspase-3 activity in the cytol and in the karyon. Despite the unknown and yet to be explored, there has been immense advancement in the development of genetically encoded biosensors. Through such devices, researches now have an increased ability to image specific biochemical and biorecognition procedures with the saving of subcellular information. Mentions 1. Campbell, R. E. Fluorescent-Protein-Based Biosensors: Transition of Energy Transfer as a Design Principle. Anal. Chem. 2009 ; 81:5972-5979 2. Ibraheem, A. and Campbell, R. E. Designs and application of fluorescent protein-based biosensors. Curr Opin Chem Biol. 2010 ; 14:30-36 3. Wang, Y. X. et Al. Fluorescence proteins, live-cell imagination, and mechanobiology: visual perception is believing. Annu Rev Biomed Eng. 2008 ; 10:1-38 4. Tsai, M. T. et Al. Real-time monitoring of human enterovirus ( HEV ) -infected cells and anti-HEV 3C peptidase authority by fluorescence resonance energy transportation. Antimicrob Agents Chemother. 2009 ; 53:748-755 5. Harvey, C. D. et Al. A genetically encoded fluorescent detector of ERK activity. Proc Natl Acad Sci USA. 2008 ; 105:19264-19269 6. Dwyer, M. A. and Hellinga, H. W. Periplasmic binding proteins: a various superfamily for protein technology. Curr Opin Struct Biol. 2004 ; 14:495-504 7. Marcaggi, P. et Al. Optical measuring of mGluR1 conformational alterations reveals fast activation, slow inactivation, and sensitisation. Proc Natl Acad Sci USA. 2009 ; 106:11388-11393 8. Kerppola, T. K. Biomolecular fluorescence complementation ( BiFC ) analysis as a investigation of protein interactions in life cells. Annu Rev Biophys. 2008 ; 37:465-487 9. Hemerka, J. N. et Al. Detection and word picture of grippe A virus PA-PB2 interaction through a bimolecular fluorescence complementation check. J Virol. 2009 ; 83:3944-3955 10. Vidi, P. A. et Al. Ligand-dependent oligomerization of Dopastat D2 and adenosine A ( 2A ) receptors in populating neural cells. Mol Pharmacol. 2008 ; 74:544-551 11. Berg, J. et Al. A genetically encoded fluorescent newsman of ATP: ADP ratio. Nat Methods. 2009 ; 6:161-166 12. Hanson, G. T. et Al. Investigating mitochondrial redox potency with redox-sensitive green fluorescent protein indexs. J Biol Chem. 2004 ; 279:13044-13053 13. Gutscher, M. et Al. Real-time imagination of the intracellular glutathione oxidation-reduction potency. Nat Methods. 2008 ; 5:553-559 14. Nakabayashi, T. et Al. Application of fluorescence life-time imagination of enhanced green fluorescent protein to intracellular pH measurings. Photochem Photobiol Sci. 2008 ; 7:668-670 15. Esposito, A. et Al. pHlameleons: a household of FRET-based protein detectors for quantitative pH imagination. Biochemistry. 2008 ; 47:13115-13126 16. Ai, H.W. et Al. Fluorescent protein FRET brace for ratiometric imagination of double biosensors. Nat Methods. 2008 ; 5:401-403 6