Biological principles Term Paper Example | Topics and Well Written Essays - 1500 words

Biological principles - Term Paper Example Simply put, all cells have basic molecular mechanisms to synthesize or absorb nutritional elements such as carbohydrates and proteins, are surrounded by a protective layer of membrane so as not to let foreign material invade them and comprise of a genetic structure that regulates their function and aids in proliferation (Gunning & Steer, 1996). Depending on the structure and functional differences, these cells can be classified into two types: prokaryotic cells and eukaryotic cells. The word ‘karyon’ means nucleus, therefore the word ‘prokaryotic’ means before nucleus- that is they do not have a nucleus, and ‘eukaryotic’ means comprising of a true nucleus. Prokaryotic organisms are always single cellular and mostly bacteria, as contrasted to the single or multicellular eukaryotes in the form of protists, fungi, plants and animals (Black, 2008). Prokaryotic and eukaryotic cells, although mostly different do have some similarities. Both of the types of cells comprise of a cell membrane, that limits the extent of the cells of both types (Black, 2008), by holding in cytoplasm and organelles. Both prokaryotic and eukaryotic cells are also similar due to the fact that they comprise of genetic material in their cells in the form of DNA (Black, 2008), which makes them capable of replicating, thus resulting in the proliferation of cells. Structurally, the prokaryotic and eukaryotic cells can be divided into their genetic and reproductive structures, and extracellular and intracellular structures (Black, 2008). The genetic material in both the types of cells is similar, however eukaryotes comprise of a double-membrane bounded nucleus that the prokaryotes do not have (Perry etal., 2013). The difference also lies in the shape of the DNA, the prokaryotic DNA is circular in shape whereas the eukaryotic DNA is in the form of multiple strands of the DNA molecule wrapped around proteins and organized in the

Do Different Detergents Effect Plant Growth?

Do Different Detergents Effect Plant Growth? Somehow, though all life on earth has been created to be equally beautiful and unique in its own way, the plant kingdom is something that always has the most astounding of wonders, flowers that are synonymous with beauty, fields that personify heavenly scenery and gigantic trees that are only a minute reminder of natures infinite power, are just the beginning of a long list of the incredible sights that the green kingdom beholds. But as everything else in the world of today, these greeneries are also strongly hit by the one common and dramatically disastrous problem: POLLUTION! The contamination of the Air, the effluence of toxic waste in precious river and lake waters and toxic wastelands of precious soil deposits play pivotal roles in the degradation of these beautiful stores of life. Water pollution, however, is the hardest hitting of the lot, with effects ranging over a large span. The effects of water pollution are far-reaching and affect not only the environment, but human beings and animals as well. Water pollution affects our oceans, lakes, rivers, and drinking water, making it a widespread and global concern. Numerous diseases, health problems, and even fatalities have been associated with water pollution. Water is considered polluted when chemicals, pathogens, or contaminants are detected. Human beings have the most crucial impact on our water resources. They also have the ability to control or eliminate water pollution. Causes of Water Pollution Farmers often use chemicals to hinder bug infestations or other diseases from damaging or ruining their crops. They may also use chemicals to enhance the growth of their crops. Either way, these chemicals seep into the ground water or run off into lakes, creeks, or rivers, causing water pollution. Farmland that is irrigated and treated with chemicals in the form of fertilizers or pesticides is a major contributor to water pollution. Industrial processes produce toxic waste containing heavy metals. When heavy metals filter into water, they are fatal to marine life. Shellfish and fresh fish are staple menu items for people around the world. Humans are affected by the heavy metals ingested by the fish and shellfish, causing health problems and sometimes death. The heavy metals in water have also been linked to severe birth defects, a damaged or suppressed immune system, cancer, fertility problems, and developmental problems in children. The construction industry is the major fault for contaminating our water resources with cement, lubricants, plastics and metals. Rivers and lakes are also polluted from heavy silt or sediment run-off from construction sites. Ground water pollution occurs when chemicals, debris, garbage, oil or other harmful contaminants enter the ground water supply over time. Ground water is often a resource for our drinking water. If it isnt treated properly, those harmful elements can cause serious health issues for human beings and domestic animals. Natural catastrophes are the cause of water pollution effects as well. Major upheavals such as storms, earthquakes, acid rain, floods, and volcano eruptions have been known to disrupt the ecological system and pollute water. The growth of algae due to food items, feces, or urea in the water source is also a source of water pollution. When algae grow in water, it uses up more than its fair share of oxygen, causing other living organisms in the body of water to suffer. Certain types of algae can be fatal if they reach an algal bloom stage, otherwise known as brown or red tides. The process of contamination begins with tiny organisms called zooplankton and travels up the food chain through clams, birds, marine creatures, and ultimately, humans. These types of algae are considered toxic because they have been known to cause fatalities in humans. Even overgrowths of non-toxic types of algae can effectively block the sunlight from penetrating the waters surface, which makes it difficult fo r marine life to find food, causing eventual death. Littering on the land or on the water is a source of water pollution. Debris tossed onto land eventually makes its way into storm drains and then returns to surface water. Ships and boats discharging human waste or chemicals into the water directly are simply speeding up the pollution process. Industrial accidents that dump chemicals into the water kill marine life swiftly and within a short period of time. As the fish and plant life decompose, further water pollution occurs. Even sunken ships are a contributor to water pollution. As the ship corrodes and decays over time, those pieces of debris or chemicals are released into the ocean or freshwater lake. Once again, marine life is affected, which means humans who eat those fish or shellfish can be adversely harmed as well. Major Effects of Water Pollution The effects of water pollution are far-reaching and affect not only the environment, but human beings and animals as well. Water pollution affects our oceans, lakes, rivers, and drinking water, making it a widespread and global concern. Numerous diseases, health problems, and even fatalities have been associated with water pollution. Water is considered polluted when chemicals, pathogens, or contaminants are detected. Human beings have the most crucial impact on our water resources. They also have the ability to control or eliminate water pollution. The effects of water pollution are numerous. Some water pollution effects are recognized immediately, whereas others dont show up for months or years. Additional effects of water pollution include:  ·Ã¢â€š ¬Ã‚  Ã¢â€š ¬Ã‚  Ã¢â€š ¬Ã‚  The food chain is damaged. When toxins are in the water, the toxins travel from the water the animals drink to humans when the animals meat is eaten.  · Diseases can spread via polluted water. Infectious diseases such as typhoid and cholera can be contracted from drinking contaminated water. This is called microbial water pollution. The human heart and kidneys can be adversely affected if polluted water is consumed regularly. Other health problems associated with polluted water are poor blood circulation, skin lesions, vomiting, and damage to the nervous system. In fact, the effects of water pollution are said to be the leading cause of death for humans across the globe.  · Acid rain contains sulfate particles, which can harm fish or plant life in lakes and rivers.  · Pollutants in the water will alter the overall chemistry of the water, causing changes in acidity, temperature and conductivity. These factors all have an effect on the marine life.  · Marine food sources are contaminated or eliminated by water pollution.  · Altered water temperatures (due to human actions) can kill the marine life and affect the delicate ecological balance in bodies of water, especially lakes and rivers. Our main aim is to reproduce our polluted environment by scaling it down to using instruments which are practical and feasible enough to use in any laboratory. Explanation of Research Question Do different concentrations of different detergent affect the growth of root and shoot in Vigna Radiata (Mung bean)? This question mainly addresses the topic of stunted growth of plants. Different detergents contain various powerful surfactants such as sodium dodecyl sulfate. These detergents characteristically aggregate lipids and denature proteins. When detergents are absorbed by a plant, the detergents can cause cell membranes to collapse and membranes to function improperly. This can cause part or all of a plant to die. Depending on the various concentrations of these pollutants, the plant shows different levels of growth, ascending from the least growth in the most concentrated of solutions (0.5%) to the highest in pure distilled water. Our main aim, under this research question, is to find out the trends in growth affection of plants that are subjected to these detergents. Materials and Methods Materials Required Surf Excel Tide washing powder Test tubes Beakers Petri dishes Mung bean Cotton Dropper Capillary tubes Distilled water Detergents detergent cartoons, detergent cartoon, detergent picture, detergent pictures, detergent image, detergent images, detergent illustration, detergent illustrations Detergents have only been around for about 85 years, even though soaps have been around for about 3,000 years. Detergents were first produced in Germany about the beginning of World War I. Plants are one of four families in scientific classification. They differ from animals in that they have chlorophyll and cell walls in their cells. Detergent is defined as a cleansing substance that acts similarly to soap but is made from chemical compounds rather than fats and lye. By the American Heritage Dictionary of the English Language. Modern detergents contain a chemical called a surfactant, which, defined by Word Net 1.6 is A substance capable of reducing the surface tension of a liquid in which it is dissolved. This allows the detergent to spread further, penetrate better and clean much more efficiently. With the addition of builders, which make the surfactants work much better. Detergents are used mainly for four different things: personal cleansing, laundry, dish washing and house cleaning. Detergent Popularity Detergents are far from being as old as soap, but today they are the best selling method of washing clothes and dishes. Detergent popularity has grown exponentially since around 1950. In between 1940 and 1972 the sales of detergents went from about 4,500 tons per year to around 4,448,000 tons per year. Detergents, as was stated, were first seen around the beginning of W.W.I. The exact year is 1916. They were first used Because of the war related shortage of fats. It was sold under the general name Nekal. The discovery of detergents was in part because the people where looking for a cleaning substance, that, unlike soaps, would not mix with the minerals in water to make a wax like residue called soap curd. They were not as high quality detergents as we have now, and were used mostly as wetting agents in textile work. The quality didnt change much in the 20s and 30s, with only minor enhancements. The sales for detergents really skyrocketed around the beginning of W.W.II, with a shortage of fats and oils needed to produce soap. The military badly needed a cleaning agent that wouldnt mix with the mineral rich waters to make soap curd. The breakthrough came at the end of the war in 1946. Up to then detergents were used for hand dish washing and washing sensitive clothing. The first all- purpose laundry detergent had surfactants and builders. The builders greatly improved the efficiency of the surfactants. By the end of 1950, soaps had almost been forgotten as a way to wash clothes and dishes, but were still used at the same time as detergents. Through the years, detergents have changed a lot. In the 50s detergents were used in dishwashers and for the laundry. They were adapted to be bleaches. Fabric softeners were also developed. In the 70s they manufactured liquid hand soap. In the 80s they made liquid dishwasher detergent, detergents for colder water washing and concentrated detergents. In the 90s they manufactured super-concentrated detergents and dishwasher gels. Detergents used: To counterfeit the pollution of natural water environments, we will use two different detergents, both of which use surfactant molecules, these have two parts. One is water loving and the other is water hating. The water-loving (hydrophilic) part breaks the surface tension of water. The water-hating (hydrophobic) part is attracted to oil and grease in soils, loosening and removing them from fabrics. Detergents usually contain more than one type of surfactant to address the needs of removing certain types of soils and cleaning different types of fabrics. The Mung bean is the name of the seed of Vigna radiata, an ovoid, greenish brown dicot which is native to parts of Bangladesh, Pakistan and India. The mung bean is one of many species recently moved from the genus Phaseolus to Vigna and is still often seen cited as Phaseolus aureus or Phaseolus adiates. These variations of nomenclature have been used regarding the same plant species. Plant Taxonomy Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Fabales Family: Fabaceae Genus: Vigna Species: V. radiata History of Plant Originally from Asia, the Chinese have been growing mung bean sprouts (Nga choy or Nga choi) for approximately 3,000 years. Farmers grow them often with little machinery. After harvest they are left to dry on gravel roads. So the dust and dirt on your mung beans that you buy from the store is actually from a road in China. Today China and India are the main producers of mung beans; it is also grown in Australia. The mung is also popular in the Philippines where they call it Munggo. Climate and Soil Mung beans are mainly cultivated in China, Thailand, Philippines, Indonesia, Burma, Bangladesh and India, but also in hot and dry regions of South Europe and Southern USA. In India and Bangladesh, they are grown during two seasons. One is the Rabi season (starting November), and the other is the Kharif season (starting June). Mung beans are tropical (or sub-tropical) crops, and require warm temperatures (optimally round 30-35 °C). Loamy soil is best for pusap cultivation. Nutritional Values Mung beans are a good source of Vitamins A, B, C E, calcium, iron, magnesium, potassium, and amino acids. Mung beans contain 20% protein and are a good source of foliate and dietary fibre. Variables: Control Amount of sunlight received by seeds Levels of Oxygen and Carbon di-oxide supplied to seeds Species of viable seeds Temperature Amount of Solution use Independent The concentration of detergents in solution (0.1% to 0.5%) Dependent The length of the shoot in Vigna radiata (in cms) The length of the root in Vigna radiata (in cms) Procedure: Cover the base of 11 different petri dishes with cotton (10 + 1 control) Mark the petri dishes according to the percentage concentration of detergent in each (From 0.1% -0.5%) Separate the petri dishes according to the detergent used, 5 with Surf Excel, 5 with Tide powder and one control dish with distilled water. Place an equal number of Vigna Radiata seeds in each petri dish (10) Ensure equal amounts of sunlight and carbon di-oxide levels to each petri dish. Tend to the seeds for 10 days and calculate root and shoot growth of seeds in all concentrations at the end of that period.

global Practice Regents Essay :: essays research papers

  Ã‚  Ã‚  Ã‚  Ã‚  Through out history, nations and regions have experienced barriers to development as a result of geographic factors.   Ã‚  Ã‚  Ã‚  Ã‚   *Japan: Japan is a mountainous region geographically isolated from the rest of the world with a lack of raw materials. They formed a barrier for trade, development, industrialization, and cultural diffusion. They attempted to adapt to the barrier by turning to imperilization of China to gain raw materials.   Ã‚  Ã‚  Ã‚  Ã‚   *Russia: Russia has very cold climatic conditions, the Ural mountains. The adapted to their geological barrier by using their weather to avoid being invaded by other nations. But they were unable to mine for minerals due to permafrost and the cold temperatures.   Ã‚  Ã‚  Ã‚  Ã‚  *Switzerland:   Ã‚  Ã‚  Ã‚  Ã‚  Waterpower is the chief natural resource of Switzerland. Granite, limestone, and other building stones and salt are the only abundant mineral resources; small deposits of iron and manganese ores are found. Agricultural resources are limited, as most of the soil is leached and stony. Neither the soil nor the climate favors agriculture, and Switzerland must import much of the food it consumes and subsidize the farms that do exist. Nearly all the farms are family enterprises, and most are small in size.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Global Regents Practice Essay No. #4   Ã‚  Ã‚  Ã‚  Ã‚  This artistic creations of different cultures reflect the values and goals of the people. These works are created in a variety of artistic mediums.   Ã‚  Ã‚  Ã‚  Ã‚   *Traditional African/Dance: Like music, African American dance is rooted in African and African American traditions. In Africa, dance is often an integral part of religious ceremonies. The degree to which African slaves were able to retain African dance forms in North America depended on their masters. In some parts of North America, dancing was frowned upon by some Protestant slave-owners as sinful. Since these slave-owners defined dancing as crossing the feet, slaves adapted their dances to conform to European beliefs, creating a shuffling motion with the feet that would be less offensive to Europeans.

Why Is Media Effects Important

16 CHAPTER 1 paradigm† (Gitlin, 1978), more powerful, yet subtle effects, such as social control, manufacturing of consent, and reluctance to challenge the status quo, are unable to be studied; so they are ignored. WHY IS IT IMPORTANT TO STUDY MEDIA EFFECTS With all these questions about the existence and substance of media effects, why is it important to continue to study them? Students in introductory mass communication courses are often reminded that mass communication is functional in society (Wright, 1986) and an important field of study because of its role as a major societal institution.Mass communication is an important economic force in the United States. In 1993, the entertainment industry alone (movies, music, cable television, and home video) brought an estimated $50 billion into the U. S. economy. Network television advertising added an additional $30 billion (Warner, 1993). Mass communication is also an important political force, acting as a watchdog over official actions and as the platform for political information and activity. The Watergate scandal, for example, was brought to light by the Washington Post and the Pentagon papers were first published by the New York Times.Political campaigns are now built around television. In 1992, the Republicans spent two-thirds of their budget on television advertisements for George Bush. Talk shows and news program coverage are crucial to campaigns. Our political leaders contact the public primarily through the mass media—press conferences, political talks. Ronald Reagan noticed that there was little political news that was made during the weekends, so he (an old radio announcer, himself) began to make radio addresses about various issues on Saturday mornings.These addresses got so much news coverage (Martin, 1984), in part because there was so little else happening, that Saturday morning radio talks are a current presidential practice. At the same time, mass media are a major source of entert ainment and the main source for news for most people. In 1995, a majority of people in the United States turned to media for news: 70. 3% were regular viewers of local television news, 67. 3% were regular viewers of network television news, and 59. 3% read a daily newspaper. In INTRODUCTION 17 addition, 48. % listened regularly to radio news and 31. 4% read a news magazine regularly (Stempel & Hargrove, 1996). Beyond the importance of mass communication in society, there are two main reasons for continuing to study media effects. The first reason is theoretical. Although most scholars acknowledge that mass media effects can occur, we still don’t know the magnitude and inevitability of the effects. That is, we don’t know how powerful the media are among the range of other forces in society. And, we don’t know all the conditions that enhance or mitigate various effects.Most importantly, we don’t understand all the processes by which mass communication can l ead to various effects. Research in media effects must continue to add to our knowledge. A second reason for studying media effects is practical and policy oriented. If we can elaborate the conditions and understand the various processes of media effects—how media effects occur—we can use that knowledge. At a practical level, understanding the processes of media effects will allow media practitioners to create effective messages to achieve political, advertising, and public relations-oriented goals.Additionally, agencies will be able to formulate media campaigns to promote prosocial aims and benefit society as a whole. That is, understanding the processes of media effects will allow media practitioners to increase the likelihood of prosocial media effects. Most importantly, understanding how media effects occur will give parents, educators, and public officials other tools to fight negative media effects. If we understand the processes of media effects, we will also un derstand how to mitigate negative effects.No longer will changing or restricting media content be the only methods to stop media effects. We will be able to mitigate negative media effects by also targeting aspects of the process of impact. WAYS TO CONCEPTUALIZE MEDIA EFFECTS: DIMENSIONS OF MEDIA EFFECTS Over the years, scholars have suggested that it is useful to analyze media effects along specific dimensions (Anderson & Meyer, 1988; Chaffee, 1977; McGuire, 1986; J. M. McLeod, Kosicki, & Pan, 1991; J. M. McLeod & Reeves, 1980; Roberts & Maccoby, 1985).Some of the dimensions delineate the type of effect; other dimensions elaborate the conditions of media impact. 18 CHAPTER 1 Cognitive-Affective-Behavioral Dimension Media effects are commonly described along a cognitive-affectivebehavioral dimension, which marks a distinction between acquisition of knowledge about an action and performance of the action. Mass communication scholars have been greatly influenced by persuasion models t hat see human action as logical and driven by cognition (e. g. , McGuire, 1985).This dimension is important in keeping scholars from assuming that knowledge and attitudes translate directly into action. Persuasion research during World War II, for example, found that although media content may be quite effective at teaching information, it had less influence on attitude formation and motivation to act (Hovland, Lumsdaine, & Sheffield, 1949). The Theory of Reasoned Action (Fishbein & Ajzen, 1975) posits that, although knowledge and attitudes have some impact on behavior, their influence is mediated (or eliminated) by social constraints.Micro- Versus Macrolevel Another dimension that describes the type of effect is one that focuses on the level of media influence: micro- versus macrolevel. Most concern about media effects focuses on impressionable audiences and has been grounded in psychological approaches. So, there is a wealth of research on media effects at the individual, or micro level. It is a fallacy, however, to assume that all media effects are accumulations of individual-level effects.Scholars recognize that a focus solely on individual-level media effects can obscure more subtle societal-level effects. Research on the effects of Sesame Street, for example, showed that children of all socioecomic status (SES) classes learned from the program. But, that learning led to another, unintended effect: a widening gap in knowledge between higher and lower SES groups. Although all children learned from the program, children from higher SES families learned at a faster rate (Cook et al. , 1975).So, individual knowledge gain may lead to greater inequities in society. Another area in which an accumulation of individual-level effects might conceal more macrolevel effects is news learning. Although many researchers have uncovered various media-related influences on public-affairs knowledge (e. g. , J. P. Robinson & Levy, 1986, 1996), these studies cannot assess the c ompleteness, accuracy, or objectivity of media’s presentations about public affairs. Several scholars argue that larger influences on news gathering and reporting may make INTRODUCTION 19 ndividual-level knowledge effects inconsequential because news sources and practices present only limited public affairs information to the public (e. g. , Gitlin, 1980; Herman & Chomsky, 1988; Tuchman, 1978). So, knowledge gain by individuals may not necessarily be functional for society. Several important effects of mass media maybe at the societal, institutional, or cultural level. Over the years, for example, the expanding telecommunications revolution has changed, and no doubt will continue to affect how political campaigns and the workings of govern-ment are conducted.Clearly, scholars need to consider various levels of media impact. Intentional Versus Unintentional Another dimension of media effects directs scholars to consider whether the effects are intended versus unintended planned for or accidental. Although this dimension is a descriptive one, it also offers some insights in the processes of media impact. For example, the development of knowledge gaps between high and lower SES children who watched Sesame Street is generally considered an unintended effect of the flow of media information. So, cholars and media policymakers study ways to close accidental knowledge gaps by increasing access to a variety of sources of information, by making information more relevant to lower SES groups, or by increasing the motivation of lower SES audience members to seek additional information. The identification of these knowledge-gap effects as accidental, then, has led scholars to focus on how knowledge is carried by the mass media, how audiences access that knowledge, and how people use media-delivered information. Another example of the relevance of the intended versus unintended dimension is one effect of television violence.The cultivation hypothesis suggests that one, often overlooked, effect of television violence is that it affects social perceptions of heavy viewers and leads those groups who are victimized in television drama to feel fearful, alienated from society, and distrusting of others (Gerbner & Gross, 1976; Gerbner et al. , 1994). If scholars believe that these effects are unintentional due to the conventions of television drama production, they might advocate certain remedies to help mitigate these effects, such as television program ratings to help fearful people avoid certain programs or to help parents screen what their children watch.If, on the other 20 CHAPTER 1 hand, scholars believe that cultivation is an intentional effect designed to reinforce the existing power structure in society by structuring reality for women and minorities so that they avoid involvement in political affairs, possible solutions would be quite different. Those scholars (at the very least) would be less trusting of television program ratings af fixed by television producers and probably not advocate that sort of solution to cultivation effects. Studying unintended effects can be a way of increasing media effectiveness.Dramatic story lines in soap operas and telenovelas have been found to not only captivate their audiences but bring about knowledge gain and some prosocial attitudinal effects (e. g. , Singhal & Rogers, 1989). So this dimension of media effects directs scholars to search for a range of effects, beyond those planned for the media producers. Content-Dependent Versus Content-Irrelevant The content-dependent versus a content- irrelevant distinction reflects the impact of specific classes of media content as opposed to the impact of media use itself.The most visible media effects research has focused on the effects of specific media content, such as stereotypes, violence, and pornography. This research assumes that specific content is linked to specific effects. As J. M. McLeod and Reeves (1980) paraphrase the nut ritional analogy, â€Å"We are what we eat†: We are what we watch. So, one way to reduce aggressive behavior in children would be to reduce the amount of violent media content that they read or watch.Or, one way to reduce sexual aggression against women would be to reduce access to media content that depicts violence against women. Although there is a good deal of evidence of the effects of specific media content, scholars should also be aware that some effects are due less to specific media content, and more to the form of the content or the act of media use. Displacement effects are a commonly identified content-irrelevant effect. Lazarsfeld and Merton (1948) suggested that political involvement could suffer if people become politically â€Å"narcotized. That is, public affairs media use might replace real political action and some people might be informed, but politically apathetic. Watching television has been attributed with lower academic achievement because children a re replacing homework and study with television watching (Armstrong & Greenberg, 1990; Hornik, 1978). INTRODUCTION 21 Other content-irrelevant effects maybe due to the form of the media presentation. Tavris (1988) is one writer who has suggested that television’s regular commercial interruptions has led to shorter attention spans.Scholars (Shannon & Weaver, 1949) investigating how information theory is relevant to media effects have found that the randomness of television’s formal features are connected to aggressive responses (Watt & Krull, 1977). Kozma (1991) speculated how the form and use of different media lead to different learning styles and outcomes. And there is a good deal of evidence that arousing media content, whether it is violent, pornographic, or suspenseful, can lead to similar excitation effects (Zillmann, 1980, 1982).In order to understand how media effects occur, we need to uncover, first, if they are content-relevant or content-irrelevant. Short Te rm Versus Long Term Media effects can be long or short term. This dimension is not only a descriptive one, but also helps describe the process of media effects. When we examine media effects, we need to question how long the effect is theoretically expected to last. Some effects, such as increased arousal (or relaxation) are relatively short term, and disappear quickly. Others, such as agenda setting, may last somewhat longer, but may disappear as the media agenda changes.Still other effects, such as the social learning of aggressive behavior, are expected to be fairly enduring, especially if the aggressive behavior, once performed, is rewarded. Some theories do not specify the persistence of their effects. Do the stereotypes that children learn from television persist even as children watch less and less television as they get older? How long do the effects of televised political ads (and their associated voting intentions) last? What are the possibilities that new ads (and new inf ormation) will change voting intentions?And what are the implications of differing periods of influence? Clearly, short-term effects can have a profound impact. If, for example, a short-term arousal effect of a violent film leads someone to get involved in a fight, permanent injury could result. But, if agenda-setting effects last only as long as an issue stays near the top of the media agenda, what long-lasting impacts can result? Media effects scholars should be clear in specifying the duration of the effects that they study. 22 CHAPTER 1 Reinforcement Versus Change A final dimension of media effects is that of reinforcement versus change.Does media exposure alter or stabilize? The most visible media effects studies focus on how media content or exposure changes the audience (or society or culture). For example, we are concerned how placid children might be changed into aggressive ones by watching violent cartoons. Or that respectful men will change into uncaring desensitized oafs through exposure to pornography. Or that voters might have their political values adjusted through exposure to political ads. Or that ignorant citizens will become knowledgeable through exposure to public affairs news.And so on. There is evidence, though, that communication’s strongest effect, overall, is reinforcement and stabilization. Selective exposure leads people to prefer media messages that reinforce their preexisting views. Selective perception points out that people interpret media content to reinforce their attitudes. Because it is often easier to observe change than reinforcement, we often neglect media’s power to stabilize. Advertisements that keep supporters active in a political campaign and keep them from wavering in support yield important effects.Media content that reinforces the already existing aggressive tendencies of a young boy may be an even more important influence than prosocial messages that have little impact. We must be careful not to equa te reinforcement effects with null effects. CONCLUSION The study of media effects is grounded in the belief that mass communication has noticeable effects on individuals, society, and culture. Evidence for these effects, though, is problematic. On one hand, despite consistence findings of effects, the variance accounted for is typically small.Moreover, the strongest effects are usually relegated to laboratory settings, which are highly artificial settings. There are, however, several reasons to expect that research underestimates media effects. Our models, theories, and methods are still imprecise; we still cannot offer complete explanations for media effects. The study of media effects remains important so that we can increase understanding of the role mass communication plays in shaping our lives. Awareness of the process of media effects will allow us to use mass communication effectively—to maximize desirable outcomes and minimize negative effects.

Laser corrective vision surgery

Clarity of vision depends upon how well cornea and lens permit rays to fall on to the retina on cones and rods. Light rays refract and bend on to focus on to the retina to form a clear image. There are two photoreceptors cones (which color sensitive) and rods (which is dim light sensitive). These send signals to brain though optic nerve. If the shape of the cornea is abnormal light does not fall properly or proper image is not formed on the back of cornea. (Fletcher, 2007) This is called refractive error. This can be corrected by refractive surgery. Refractive errors include myopia (nearsightedness), hyperopia (farsightedness), astigmatism (an irregularly shaped cornea which causes blurring), and presbyopia (similar to hyperopia, a condition which causes the lens to harden). Refractive eye surgery helps to reduce or eliminate a person's dependency on eyeglasses or contact lenses. (NYP, 2007) There are several types of refractive surgery; proper diagnostics can only determine which is needed by whom. It can well be stated that â€Å"compared with surface ablation, LASIK results in earlier and faster improvement of uncorrected visual acuity, and has less (or almost no) postoperative discomfort, improved stability, and predictability.† (Agingeye, 2007) At the same note it can also be stated that â€Å"with LASIK, however, the risks of flap-related complications (wrinkles, debris, folds, buttonhole, and diffuse lamellar keratitis) may be associated with the creation of the lamellar flap.† (Agingeye, 2007) Precautions of laser correction surgeries are 1)  Ã‚  Ã‚  Ã‚   Eyes should be healthy 2)  Ã‚  Ã‚  Ã‚   Patient should be adult 3)  Ã‚  Ã‚  Ã‚   Stable vision for a year or so. 4)  Ã‚  Ã‚  Ã‚   If pregnant surgery should be performed on after evaluating the shape of corneas. 5)  Ã‚  Ã‚  Ã‚   Should not have Degenerative or autoimmune diseases. (Allaboutvision, 2007) Some of risks in LASIK are 1)  Ã‚  Ã‚  Ã‚   Some patients lose vision 2)  Ã‚  Ã‚  Ã‚   Some patients develop debilitating visual symptoms. 3)  Ã‚  Ã‚  Ã‚   irregular astigmatism, which can decrease the corrected vision 4)  Ã‚  Ã‚  Ã‚   corneal haze or glare 5)  Ã‚  Ã‚  Ã‚   overcorrected or undercorrected vision 6)  Ã‚  Ã‚  Ã‚   inability to wear contact lenses in the future 7)  Ã‚  Ã‚  Ã‚   loss of the corneal flap, requiring a corneal graft 8)  Ã‚  Ã‚  Ã‚   scarring 9)  Ã‚  Ã‚  Ã‚   infection (Roberts, 2007) 10) vision loss 11) develop severe dry eye syndrome 12) Irregular Astigmatism 13) Keratectasia 14) Night Vision Problems or Night Glare and Halos 15) Central Islands 16) Epithelial Ingrowth Diffuse Lamellar Keratitis (DLK) (Banerjee, 2005) Lasik has its benefits too. It is performed under a protective layer of corneal tissue. As a result, there is less surface area to heal, less risk of scarring, less risk of corneal haze, less postoperative discomfort, less postoperative need for medications, and vision returns more rapidly, often within a day or so. It can an also treat a higher range of vision errors. (Grochmaleye, 2007) One testimony to this is available from the US military. It is stated that â€Å"the U.S. military also has adopted widespread use of refractive surgery including LASIK to decrease reliance of troops on artificial lenses or eyewear as evidenced by the more than 16,000 U.S. Army personnel who underwent refractive surgery from 2000 through 2003. Studies of these outcomes showed that 86% achieved 20/20 or better uncorrected vision and 98% achieved 20/40 or better, which legally is considered good enough for driving without eyewear or contact lenses.† (Allaboutvision, 2007) Some Statistics are in this context can be stated as follows: Patient Results Three Months After Treatment Procedure 20/20 or Better 20/40 or Better LASIK for myopia 42.0% to 84.8% 76.8% to 99.4% LASIK for hyperopia 48.8% to 58.3% 93.4% to 98.3% PRK for myopia and hyperopia* 67% (approximate) 95% (approximate) (AAO, 2007) In conclusion it can be stated that the method has both positive and negative aspects. It should be remembered that the use of laser was approved by the FDA’s Medical Devices Advisory Committee in the context of the Ophthalmic Devices Panel and the effectiveness and safety was proved with the help of various clinical studies. (FDA, 2007) The FDA evaluated several case studies on the method and after analysis of 1,013 eyes LASIK performances that was carried out in thirteen centers of medicine over the period of half year it was found that â€Å"of the 1,013 eyes treated, 92 percent were corrected to 20/40 or better and 47 percent were corrected to 20/20 or better without glasses or contact lenses.† (FDA, 2007) However, in accordance to FDA it could be stated that â€Å"short-term side effects included pain (for 24 to 48 hours), corneal swelling, double vision and light sensitivity. In some patients these effects lasted for several weeks.†(FDA, 2007) Thus this could be termed as a well tested process but it needs more time and application to become a complete water-tight method. It could be stated that more work on the subject is necessary. References: American Academy of Ophthalmology; (2007); Ophthalmology Report 2007; Sydney: Allied Publications Allaboutvision; (2007); Lasik Criteria; allaboutvision.com; retrieved on 10.02.2008 from http://www.allaboutvision.com/visionsurgery/lasik-criteria.htm Allaboutvision; (2007); Lasik complication; allaboutvision.com; retrieved on 10.02.2008 from http://www.allaboutvision.com/visionsurgery/lasik_complication_1.htm Banerjee, D; (2007); Details from Medical Journals of AIIMS; New Delhi: AIIMS Fletcher, R; (2007); Medical Principals: Beliefs and Knowledge; Believing and Knowing; Dunedin: Howard ; Price Grochmaleye; (2007); Lasik benefits; grochmaleye.com; retrieved on 10.02.2008 from http://www.grochmaleye.com/lasik_benefits.html