Rectification circuit for a dc power supply

Rectification circuit for a dc power supply 1. Introduction Most of the electronic devices do not power on AC basis, and if so it will conduct a lot of power and will be damaged the first moment it operates. Thus a device that reduces the voltage and correspondingly smoothes the output voltage to become much more stable and reliable to use than the AC which is the DC is needed. A question may arise that asks why do not use batteries to supply a DC voltage. Well, it is a good it a good question, but batteries are expensive and does not handle large electronic devices. Imagine having a desktop on batteries and having to change its battery every half an hour or so, it is a nightmare. As a result, in this case, a linier DC power supply that operates from fixed (ex: at home) AC voltage is needed. A rectification circuit do all that automatically. It smoothes and filters the current and make it a better than a battery DC source. The report paper will focus primarily on the technical aspects of the Rectification circuit used in the linear DC power supply. Other aspects than mentioned will not be included. 2. Discussion 2.1. Linear power supply AnACpowered linear power supply usually uses atransformerto convert the voltage from the wall outlet (mains) to a different, usually a lower voltage. If it is used to produceDC, arectifieris used. A capacitoris used to smooth the pulsating current from the rectifier. Some small periodic deviations from smooth direct current will remain, which is known asripple (Wiki, 2009). The voltage produced by an unregulated power supply will vary depending on the load and on variations in the AC supply voltage. For critical electronics applications alinear regulatorwill be used to stabilize and adjust the voltage. This regulator will also greatly reduce the ripple and noise in the output direct current. Linear regulators often provide current limiting, protecting the power supply and attached circuit from over current (Wiki, 2009). Figure 1 illustrates two common linear power supply circuits in current use. Both circuits employ full-wave rectification to reduce ripple voltage to capacitor C1. The bridge rectifier circuit has a simple transformer but current must flow through two diodes. The centre-tapped configuration is preferred for low output voltages since there is just on diode voltage drop. For 5V and 12V outputs, Schottky barrier diodes are commonly used since they have lower voltage drops than equivalently rated ultra-fast types, which further increase power conversion efficiency. However, each diode must withstand twice the reverse voltage that a diode sees in a full-wave bridge for the same input voltage. The linear voltage regulator behaves as a variable resistance between the input and the output as it provides the precise output voltage. One of the limitations to the efficiency of this circuit is due to the fact that the linear device must drop the difference in voltage between the input and output. Consequently the power dissipated by the linear device isVi-VoÃÆ'- Io. While these supplies have many desirable characteristics, such as simplicity, low output ripple, excellent line and load regulation, fast response time to load or line changes and low EMI, they suffer from low efficiency and occupy large volumes. Switching power supplies are becoming popular because they offer better solutions to these problems (National, 2002). 2.2. Transformer Atransformeris a device, figure 2, that transferselectrical energyfrom onecircuitto another throughinductively coupledconductorsà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬the transformers coils. A varyingcurrentin the first orprimarywinding creates a varyingmagnetic fluxin the transformers core, and thus a varyingmagnetic fieldthrough the secondarywinding. This varying magnetic fieldinducesa varyingelectromotive force (EMF)or voltage in the secondary winding. This effect is called mutual induction. If aloadis connected to the secondary, an electric current will flow in the secondary winding and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the secondary winding (VS) is in proportion to the primary voltage (VP), and is given by the ratio of the number of turns in the secondary (NS) to the number of turns in the primary (NP) as follows: Step down transformers convert electrical voltage from one level or phase configuration usually down to a lower level. They can include features for electrical isolation, power distribution, and control and instrumentation applications. Step down transformers typically rely on the principle of magnetic induction between coils to convert voltage and/or current levels. Step down transformers are made from two or more coils of insulated wire wound around a core made of iron. When voltage is applied to one coil (frequently called the primary or input) it magnetizes the iron core, which induces a voltage in the other coil, (frequently called the secondary or output). The turns ratio of the two sets of windings determines the amount of voltage transformation. An example of this would be: 100 turns on the primary and 50 turns on the secondary, a ratio of 2 to 1. Step down transformers can be considered nothing more than a voltage ratio device. With step down transformers the voltage ratio between primary and secondary will mirror the turns ratio (except for single phase smaller than 1 KVA which have compensated secondarys). A practical application of this 2 to 1 turns ratio would be a 480 to 240 voltage step down. Note that if the input were 440 volts then the output would be 220 volts. The ratio between input and output voltage will stay constant. Transformers should not be operated at voltages higher than the nameplate rating, but may be operated at lower voltages than rated. Because of this it is possible to do some non-standard applications using standard transformers. Single phase step down transformers 1 kva and larger may also be reverse connected to step-down or step-up voltages. (Note: single phase step up or step down transformers sized less than 1 KVA should not be reverse connected because the secondary windings have additional turns to overcome a voltage drop when the load is applied. If reverse connected, the output voltage will be less than desired). 2.3. Rectifier Arectifieris an electrical device that convertsalternating current(AC) todirect current(DC), a process known asrectification. Rectifiers have many uses including as components of power suppliesand asdetectorsofradiosignals. Rectifiers may be made ofsolid statediodes,vacuum tubediodes,mercury arc valves, and other components (Wiki, Rectifier, 2009). While half-wave and full-wave rectification suffice to deliver a form of DC output, neither produces constant-voltage DC. In order to produce steady DC from a rectified AC supply, a smoothing circuit orfilter,is required. In its simplest form this can be just areservoir capacitoror smoothing capacitor, placed at the DC output of the rectifier. There will still remain an amount of ACripplevoltage where the voltage is not completely smoothed. Sizing of the capacitor represents a trade-off. For a given load, a larger capacitor will reduce ripple but will cost more and will create higher peak currents in the transformer secondary and in the supply feeding it. In extreme cases where many rectifiers are loaded onto a power distribution circuit, it may prove difficult for the power distribution authority to maintain a correctly shaped sinusoidal voltage curve (Wiki, Rectifier, 2009). For a given tolerable ripple the required capacitor size is proportional to the load current and inversely proportional to the supply frequency and the number of output peaks of the rectifier per input cycle (National, 2002). The load current and the supply frequency are generally outside the control of the designer of the rectifier system but the number of peaks per input cycle can be affected by the choice of rectifier design. A half-wave rectifier will only give one peak per cycle and for this and other reasons is only used in very small power supplies. A full wave rectifier achieves two peaks per cycle and this is the best that can be done with single-phase input. For three-phase inputs a three-phase bridge will give six peaks per cycle and even higher numbers of peaks can be achieved by using transformer networks placed before the rectifier to convert to a higher phase order (Wiki, Rectifier, 2009). To further reduce this ripple, acapacitor-input filtercan be used. This complements the reservoir capacitor withinductor and a secondfilter capacitor, so that a steadier DC output can be obtained across the terminals of the filter capacitor. A more usual alternative to a filter, and essential if the DC load is very demanding of a smooth supply voltage, is to follow the reservoir capacitor with avoltage regulator. The reservoir capacitor needs to be large enough to prevent the troughs of the ripple getting below the voltage the DC is being regulated to. The regulator serves both to remove the last of the ripple and to deal with variations in supply and load characteristics. It would be possible to use a smaller reservoir capacitor (these can be large on high-current power supplies) and then apply some filtering as well as the regulator, but this is not a common strategy. The extreme of this approach is to dispense with the reservoir capacitor altogether and put the rectified waveform straight into a choke-input filter. The advantage of this circuit is that the current waveform is smoother and consequently the rectifier no longer has to deal with the current as a large current pulse, but instead the current delivery is spr ead over the entire cycle. The downside is that the voltage output is much lower approximately the average of an AC half-cycle rather than the peak. 2.4. Regulator The regulator is an electrical regulator designed to automatically maintain 3. The Proposed Circuit * The proposed circuit shall have an input voltage equals to 220v. * A centre-tapped step down transformer with 220v output and 12v output. * 2 diodes (1N4001) working independently (note: duel regulated) as half-wave rectifiers. * 2 capacitors (1000u) to smooth the signal. * 2 voltage regulators (LM7815C) to regulate the coming voltages from the capacitors. * 2 small values capacitor (10u) for final smoothing for the output voltage. * The output voltage of 0-5v. 4. Conclusion One of the best ways to output an efficient and reliable DC power supply is to use linear power supply, which uses a step-down transformer, a rectification circuit, a regulator and a filter. The step-down transformer takes the voltage down from 220v to 12v, then the rectification circuit smoothes and filters it using capacitors and diodes, as a result, the output DC voltage would be 0-5v with a minimal ripple factor using the proposed circuit as mentioned. Works Cited National, S. C. (2002, September 1). Introduction to Power Supplies. Santa Clara, California, USA. Wiki. (2009, December 10). Power supply. Retrieved December 14, 2009, from Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Power_supply Wiki. (2009, December 9). Rectifier. Retrieved December 16, 2009, from Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Rectifier Power supply. Retrieved December 15, 2009, from: http://www.kpsec.freeuk.com/powersup.htm http://www.allaboutcircuits.com/vol_3/chpt_3/4.html Wiki. (2009, December 12). Rectifier. Retrieved December 15, 2009, from Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Voltage_regulator AC to DC Cuircts. Retrieved December 16, 2009, from: http://www.discovercircuits.com/DJ-Circuits/acdc1.htm Power supply. Retrieved December 15, 2009, from: http://www.trcelectronics.com/power-supply.shtml Step-down transformers. Retrieved December 14, 2009, from: http://www.powertransformer.us/stepdowntransformers.htm Step Down Transformers. Retrieved December 15, 2009, from: http://www.electricityforum.com/electrical-transformers/step-down-transformers.html

Emotional, Behavioral, and Psychological Disturbances in Neglected Chil

Every year millions of children are abused and neglected worldwide. Child abuse is a global concern. It has severe outcomes on the children who are victims, and often the effects are long-lasting. Child abuse is a highly under-reported crime although of those reported, neglect accounts for the majority of child abuse cases (Pala, ÃÅ"nalacak, & ÃÅ"nlà ¼oÄŸlu, 2011). Neglect in children often has more dire consequences than other types of child abuse (DePanfilis, Children’s Bureau, & Office on Child Abuse & Neglect, 2006). One consequence especially prevalent in neglected children is insecure or lack of attachment to a primary caregiver. John Bowlby’s research has shown the evolutionary importance of infant attachments, further research shows that infant attachment styles carry over into adulthood (Levine & Heller, 2011). Neglected children showed disturbed attachments that manifest into developmental delays and behavioral problems. Through treatment neglected childr en aim to learn how to create secure attachments (Hardy, 2007). Defining neglect Numerous teachers, family doctors, social workers, among other professionals will be faced with child abuse and have the responsibility of reporting mistreatment. Therefore, it is important for these specialists to be able to recognize signs of child abuse and neglect (Pala, et al, 2011). The World Health Organization Consultation on Child Abuse Prevention currently recognizes four types of child abuse: physical, sexual, emotional, and neglect. Dr. Bengà ¼ Pala and his colleagues found that neglect accounted for up to 71% of the child abuse cases in 2008 around the world. They defined neglect as a parent or caregiver’s precedence of failure to provide for the development and welfare of the child ... ...on regulation and emotional stability (Hardy, 2007). From 2000 to 2004, 7.6 out of every 1,000 children were reported as being neglected. The Third National Incidence Study of Child Abuse and Neglect found that less than a third of child maltreatment is reported. The signs of neglect can often be subtle and hard for other adults to recognize; this attributes to the underreporting of neglect cases (DePanfilis, et al., 2006). Due to the fact that child abuse distresses millions of children every year and millions more suffer silently, it is important to improve research on the dilemma. Several studies acknowledge that there is an absence of research on attachment theory in neglected children (Venet et al.) It is imperative that research on attachment disorders drastically advance so that effective treatments can be developed allowing neglected children to heal.

Essay --

â€Å"Heroes take journeys, confront dragons, and discover the treasure of their true selves.†- Carol Lynn Pearson. Heroes have many different qualities depending upon the person you believe is a hero in your eyes. A Hero’s qualities could be being Brave, Trustworthy, Loving, a Leader, Intelligent, and Kind. Now those are just some common characteristics to â€Å"make† or to â€Å"be† a hero. Some heroes to others could be in their family, their friends, or even famous people that have passed or are still alive. A characteristic that stands out to many is Bravery. Being a brave person can be challenging. Martin Luther King Jr., for example, is a brave person and a hero. † A man who won't die for something is not fit to live†-Martin Luther King, Jr. He stood up for what he believed in and stood up for all of the ones who were frightened to say something. His speech,† I Have a Dream† caught the attention by everyone in the whole entire world. Martin was arrested upwards to about twenty times and was assaulted about four times (nobelprize.org/MartinLutherKingJr.). How could Martin Luther not be a hero? He risked his life for Blacks and for their rights. Would you do this if you were in his shoes? Another example of a Brave hero would be Anne Frank. † And finally I twist my heart round again, so that the bad is on the outside and the good is on the inside, and keep on trying to find a way of becoming what I would so like to be, and could be, if there weren't any other people living in the world†-Anne Frank. Even though she was younger and may not have understood everything, she was still a brave and strong person. She had to go into hiding to save her life and her families. They all had to stay quiet and get along with all the families they were ... ...n a season, and the most valuable player of the year. All of his awards and accomplishment showed that it doesn’t matter what you like. Appearance doesn’t determine if you are skilled or not, if you are brave, or even a hero. In conclusion, the qualities are what make up a hero. Not the ways they look, act, or speak, but they all have one thing in common which is standing for what they believe in. In any situation that occurs. Someone’s appearance does not prove or show you what they can do or how they can act. A hero’s actions or skills are what make them a hero. You don’t have to be a superhero with a cape or a muscular man to make everyone think you are a hero. You could be the quietest person in the school or your town for that matter. If you are willing to stand for what you believe in and do what you think is the right decision, you could be a hero to many.

Moving Towards Totalitarianism in Our Pursuit of Social Justice Essay

Moving Towards Totalitarianism in Our Pursuit of Social Justice Pursuit of various visions of social justice probably accounts for most human misery. What's more, the historical pattern that has emerged has been one whereby one form of injustice is replaced by one that is far worse. Russia's 1917 revolution expelling the Czars, and their injustices, ushered in Lenin, Stalin and a succession of brutal dictators who murdered tens of millions in the name of the proletariat revolution. The injustices of Chiang Kai-shek were replaced with those of Mao Tse-tung; Castro's ousting of Batista or Ayatollah Khomeini's toppling of the Shah of Iran produced regimes far more brutal. In Africa, after independence, the injustices of colonial powers were replaced with those of brutal dictators. The slaughter of nearly 200 million poor souls, not including war deaths, during the 20th century, was a direct result of pursuit of visions of social justice such as income equality, promoting the common good and fighting the so-called evils of capitalism. As if by design , measures taken to produce what was seen as the good society lowered both the common man's human rights protections and his standard of living. By contrast, after the American revolution, we laid the groundwork that produced the world's freest people. However, for most of the 20th century, we have been losing ground. If you ask the question which way are we heading - away from totalitarianism or towards it - there is no question that, by tiny steps at a time, we are heading towards totalitarianism and arbitrary governmental abuse and control. Some Americans are naive enough to think that the oppression seen in other countries can't happen here. But let's not forget that the countr... ...t determine what is or is not moral conduct. In Nazi-Germany, there were laws that required the reporting of a person hiding a Jew. In our country, the Fugitive Slave Act made assisting runaway slaves a crime. In apartheid South Africa, hiring blacks for certain work was illegal. In the former East Germany, assisting people in their efforts to escape to the West was illegal. Would any decent person demand that any of these laws be obeyed? Decent people must always ask: Does the law have a moral basis? Liberty is not mankind's normal state of affairs. Liberty is fragile. Our liberties are under siege because most Americans are ignorant about our Constitution and its philosophical underpinnigs. Thus, we fall easy prey to political charlatans and quacks all too ready to exploit this ignorance in their quest for power and to satisfy popular visions of social justice.

Michigan

Despite the governor’s pretty language abot alternative fuels and efforts to create a partnership with Sweden for the development of alternative fuel use in Michigan, the state is still nowhere near where it should be in terms of use of alternative fuels. The reasons are simple and complex all at the same time. People don’t want to buy vehicles which use alternative fuels if they can’t buy that fuel at the local store and local stores don’t want to carry a product that no one is buying.  Ã‚   On a website for Ford Truck enthusiasts,   one consumer said he would love to have a biodiesel truck or a flex fuel Ford Ranger, but even with the incentives the state has adopted to promote the use of these fuels, they are not generally available at the corner store. In addition, Michigan’s incentives, such as a 12 cents per gallon sales tax credit on some alternative fuels, do not account for market fluctuations that are inherent in a system that relies on only ethanol and oil fuels. In the worst conditions, extreme versions of the summer of 2007, a drought in major corn-producing states could raise the price of ethanol and OPEC production games can increase the price of gasoline. Because biodiesel and other alternative fuels are not easily used in most vehicles, consumers are still caught in a Catch-22. Switching to one alternative fuel does not make it readily available. With diversification as the car manufacturers look for more efficient ways to propel their vehicles and save the environment,   consumers cannot be assured that their â€Å"alternative fuel† vehicle of today is not going to be an obsolete paperweight with no fuel available in just a few years. The sad thing is that for all the attacks on the automotive industry, Michigan and automakers are trying to come up with a solution for the environment and for business. Unfortunately, the businesses and researchers can’t agree on what the best alternative fuel source is.   Ethanol relies of the growing season, propane is still a fossil fuel and methane is difficult to transport safely. Biodiesel, a form of heavy vegetable oil, also requires good crops. With shifting weather patterns across the globe, manufacturers are loathe to rely on a system which necessitates a good growing season. Furthermore, many activists are now arguing that the farmland used to create corn and soy beans for use in alternative fuels further contributes to the global warming problem by destroying farmland. In short, Michigan is trying to address the alternative fuel needs of the state and the country, but until the technology and production capability meet, consumers are less likely to buy into the alternative fuel option than officials would like. Hybrids are popular, but largely unproven in terms of long-term mechanical durability and alternative fuel cars just aren’t attractive for mass consumption. Until Michigan can do something about the supply chain for alternative fuels and the reliability of cars built to use them, the alternative fuels effort in Michigan will be strong, but not terribly effective.

Is the Earth large or small? Essay

Any information concerning the size of the earth is likely to refers to this aspect its description within the context of relativity. As one of the planets in the solar system, the earth is large relative to its planetary counterparts. It is the largest and most massive of the terrestrial planets (which include Mars, Venus, and Mercury) within the solar system. In addition, the earth is also denser than the other planets within its solar system. However, compared with the non-terrestrial planets (Saturn, Jupiter, Uranus and Neptune) the earth is very small. In comparison with the sun, the earth is tiny. The mass of the earth is 5. 9736 X 1024 kg. This, compared with the mass of the sun is 1. 99 X 1030 kg, which is 332,946 times that of the earth. On the size scales within the solar system, therefore, the earth might be considered medium sized. However, since the sun is quite miniscule compared to other stars and to the physical bodies within and beyond the galaxy, the sizes of the earth on a universal scale approaches the infinitesimal. 2. What are the major differences between parallels and meridians? Parallels or latitudes differ from meridians primarily in the directions in which they run. While parallels always run east-west, meridians run north-south in a way that allows each to cut (cross) each parallel at a different angle. This is because meridians all run through the axes of the earth, and this ensures that they all converge upon the poles. The parallels or latitudes run parallel to each other, and this ensures that they never meet each other in their journeys around the earth. One effect that this difference (in parallelism) has on the two types of lines is that while parallels are always equidistant from the equator and poles at every point on its circumference, meridians change their distances from each other the closer or further away they are from the poles. Therefore, at the equator, the distance between any two given meridian will always be greater than at any other latitude on the earth. 3. Why are vertical rays of the Sun never experienced poleward on the tropic lines? The sun’s vertical rays are experienced only between 23. 5oN and 23. 5oS primarily as a result of the tilt of the earth’s axis. This tilt measures 23. 5 degrees, so as the earth revolves around the sun, its poles tilt toward or away from the sun at this angle. During the summers (which alternate between opposing parts of the year in for the northern and southern hemispheres), the poles are tilted toward the sun. However, the angle this causes the earth to make with the sun ensures that the angles of the sun-rays hitting the earth are less than the 90 degrees which would constitute a direct hit. Because of this tilt, the rays of the sun are sometimes able to shine directly on such parts of the earth that always between the latitudes that remain in the direct path of the rays after the 23. 5o tilt. The further north or south of these latitudes one goes, the less of a direct contact the earth makes with the sun’s rays. In fact, the extreme of this is that very close to the poles at certain times of the year, the sun’s light is not seen at all. 4. On which day of the year do the vertical rays of the Sun strike the farthest north of the Equator? What is the latitude? Why? The days on which the sun’s vertical rays hit the earth at the angle farthest from the equator is approximately December 22. This is known as the Winter Solstice, and describes the time when the Northern Hemisphere experiences its shortest daytime period (or longest night-time period). The latitude at which this occurs is the 23. 5oN, which represents the latitude of the Tropic of Cancer. This occurs primarily because of the earth’s axial tilt, which is about 23 degrees toward or away from the sun. At the time of the Northern Hemisphere’s Winter Solstice, the earth is tilted away from the sun, yet the sun’s direction from the earth at that time compensates for that tilt so that its rays hit at the spot farthest north that is possible at any given time. This â€Å"spot† occurs at 23o north of the equator. 5. Explain the implications of the statement, ‘No map is totally accurate. ’ According to mapping standards held by the Unites States (and likely by other countries), maps have to maintain accuracy within a given scale. For example, for scales where one (1) inch on the map represents 24,000 inches on land (or sea), the inaccuracy level of the map should not exceed 1/50th of an inch in more than 10% of the points (USGS). These standards are based upon the premise or understanding that no map can be completely accurate. However, what this means is that at minute scales on the ground or sea, it becomes impossible to locate things with a large degree of accuracy. This can be seen more clearly when it is known that 1/50th of an inch on a 1:24,000 scale represents 40 feet (USGS). Therefore, in important expeditions that require map use, a user may expect to be ignorant concerning the exact location of a designated point within at least a 40-foot radius. 6. A globe can portray Earths surface more accurately than a map, but globes are rarely used. Why? Globes are more accurate than maps because, while the map distorts the latitude lines, the shapes of its landmasses and other features, these are kept in true to form on globes. However, globes are rarely used because of their three-dimensional natures that make them more difficult to navigate than two-dimensional maps. The shapes made by the intersection of parallels and meridians are also less like simple geometrical shapes. Because of the way in which the latitude lines are portrayed on maps (as vertical and parallel, thereby creating the illusion of squares) these are usually more suited to calculations done by the lay person or navigator. These parallel latitudes represent not real latitude lines but what has been termed loxodromes (also known as rhumb lines). These rhumb lines actually represent the constant bearing of a compass and calculations using these lines make it easier for navigators to determine the direction of their courses (Rosenberg). Maps are also more intuitively like humans view the surface of the earth. From our perspective, it does not appear to be a sphere, but a large expansive area. Therefore, maps accord more to our everyday experience and are easier for humans to translate. 7. Distinguish between GPS and GIS. Provide ways in which these tools can be useful to physical geographers. The Global Positioning System or GPS is a system that facilitates the location of objects or areas on or around the earth based on a group of satellites which have been launched into the earth’s orbit at about 11,000 miles (Corvallis). This differs from a GIS, which is a Geographical Information System—a database that holds the location of a large number of locations on the earth. The difference between the two lies in that while the GPS is the system for mapping an object, the GIS is the actual object that whose position is being mapped. The GPS system is of immense importance because of the level of accuracy it provides whether on the scales required by navigators or those required for geodesic positioning (ISSA). GIS allows geographers to be able to know, map, and locate specific regions or objects on the earths surface. It also allows them to chart paths from one location to the next by accurately calculating vectors that denote the relative distances and directions between given locations. The GPS continually expands the data available by embodying the technology that allows new places to be located and pin-pointed. Works Cited Corvallis. â€Å"Introdiction to the Global Positioning System for GIS or TRAVERSE. † CMTINC. com.Corvallis, OR: Corvallis Microtechnology Incorporated. http://www. cmtinc. com/gpsbook/index. htm ISSA. â€Å"The Global Information System. † The International Strategic Studies Association. 2004. http://128. 121. 186. 47/ISSA/gis/index. htm Rosenberg, Matt. T. â€Å"Peters Map vs. Mercator Map. † About Geography. New York: New York Times Company. http://geography. about. com/library/weekly/aa030201b. htm USGS. â€Å"Map Accuracy Standards. † United States Geographical Survey. Reston: U. S. Department of the Interior. 1999. http://erg. usgs. gov/isb/pubs/factsheets/fs17199. html

Digital Media

Introduction: You may have heard of digital media, but you may have no idea what it is and how it can help you out when it comes to marketing. It's definitely important that you get up to speed so you can use this to benefit your business. Basically digital media refers to any type of electronic media out there. Today media can be accessed in many ways, including with hand held devices like mobile phones, laptops, desktops, mp3 players, and more. Digital media must be stored in an electronic way, so there is a lot of digital content on the internet today, including text content, pictures, audio content, as well as video content.Through the history of internet, digital media has been developing in various ways. Here's we'll take a look at how it has affected the Internet and ways that it may be integrated moving forwards (Rogers 2006). One type of digital media is text; this in fact represented the very first explosion of  this  type of content  out there on the Internet. When t he Internet first got big, there was an explosion of content on the web, especially with all the text editors and word processing options out there today (Rogers 2006).Larger companies started to put date on computers instead of storing it in cabinets, and the internet definitely allowed a great way to share, transfer, and store content as well. As the Internet grew, images began to appear. Instead of just text emails, soon people could send photos, and soon photo sites for sharing photos began to pop up. Then in the middle 1990s, audio began to become an important part of digital media with the mp3 files that could be easily used. Soon music and more was shared online with sites that allowed you to share audio.Last in the digital media development was video. YouTube definitely made video sharing a hugely popular form of modern media distribution and this is continuing to grow as we speak today. Now with new technology seen in things like the iPhone,  this new form of virtual medi a  is available in handheld devices as well, and no doubt  this sector  is only going to continue to grow in the future (Rogers 2006). Now that you understand a bit more about the technology side, you may be wondering how it can help your business.Well businesses are using digital media for marketing more and more today, realizing that there is a huge marketing field out there and that  it can help to draw in visitors and can even provide better search engine visibility with you. Text content can be kept updated on your site and helpful content is a great part of good marketing. Expertise in your field can really help your business and get traffic flowing into your business website. Photos, charts, diagrams, and models are always popular online and will help you to get more visibility as well.Audio allows you to use music on pages or to do podcasts for your business. Creating videos is a popular method of digital media marketing today, and videos do very well in search engin es (Rogers 2006). With the popularity of digital media, it is definitely important that you continue to create and use it for good marketing and business results. Even if you have to hire someone to help out, the benefits will make it worth the money. So knowing about and using digital media is definitely important for your business success todayProblem statement: Most people accept the idea that the media can influence people. But the degree of that influence, as well as who is most-impacted, when, how and why, have been the subjects of great debate among communication scholars for nearly a century. Media effects refers to the many ways individuals and society may be influenced by both news and entertainment mass media, including film, television, radio, newspapers, books, magazines, websites, video games, and music.To understand digital media effects, it is first critical to consider how media are used and for what purposes. Communication scholars have traditionally fallen into tw o camps – functionalists, who believe the media audience tends to be in control and active, and critical/culturalists who believe the audience has less control and is therefore more passive. The balance may lie somewhere in the middle and may vary from country to country. Purpose of the study: In this paper we are going to study and evaluate the digital media and its effect on children in general.The following text is a general idea: Youth spend an average of ;7 hours/day using media and the vast majority of them have access to a bedroom television, computer, the Internet, a video-game console, and a cell phone. In this paper we review the most recent research on the effects of media on the behavior and health and well-being of children and adolescents. Studies have shown that media can provide information about safe health practices and can foster social connectedness.However, recent evidence raises concerns about media's effects on aggression, sexual behavior, substance use , disordered eating, and academic difficulties. We provide recommendations for parents, practitioners, the media, and policy makers, among others, for ways to increase the benefits and reduce the harm that media can have for the developing child and for adolescents. More than 50 years of media research attests to the significant influence of media on child and adolescent health.Both â€Å"old† media (television, movies, magazines) and â€Å"new† media (the Internet and social networking sites, video/computer games, cell phones) can have an impact on virtually every health concern that practitioners and parents have about young people, including aggressive behavior, risky sexual behavior, substance use, and disordered eating. Although the media are not the leading cause of any of these problems, the research reviewed here suggests that they are significant.Yet, despite the evidence of potential harm, there is also evidence that media can be beneficial for youth (eg, by increasing empathy and acceptance of diversity through modeling of prosocial behaviors and developing children's early literacy skills through educational programming). Those concerned with child and adolescent health need to be aware of the research on the effects of modern media on youth. Theoretical framework: Literature review: Media affect youth not only by displacing time they spend doing homework or sleeping but also by influencing beliefs and behaviors.According to social learning theory, children and adolescents learn by observing and imitating what they see on the screen, particularly when these behaviors seem realistic or are rewarded. Cognitive development theory asserts that children's cognitive capacities at different stages determine if and how they understand media content. For example, children younger than 8 years who are not yet able to comprehend persuasive intent will be more vulnerable to advertising.In addition, media present youth with common â€Å"scriptsâ €  for how to behave in unfamiliar situations such as romantic relationships. Finally, superpeer theory states that the media are like powerful best friends in sometimes making risky behaviors seem like normative behavior. With the variety of theories suggesting a potentially powerful effect of the media and the growing empirical evidence for negative impact, one might hypothesize that parents would take care to limit exposure to detrimental media content.However, the â€Å"third-person effect† (a well-documented phenomenon in the communications literature) shows that teenagers and adults think that the media influence everyone except themselves or their children Violence and Aggression By the age of 18, the average adolescent will have seen an estimated 200 000 acts of violence on television alone. Much of the violence on television and in movies is presented in a sanitized and glamorized fashion, and in children's programming it often is presented as humorous.More than 1 0% of 10- to 14-year-olds saw 40 of the most violent movies in 2003. Both music videos and rap music have become increasingly violent. Interactive media can encourage antisocial beliefs and behavior in children and adolescents, particularly because violence in new media has been found to be prevalent as well. A recent analysis of video games revealed that more than half of all games contain violence, including ;90% rated as appropriate for children aged 10 years and older.Health professionals worry most about first-person shooter video games. In the aftermath of the West Paducah, KY school shooting, it was discovered that the shooter had never fired a real gun in his life before that day, yet his marksmanship was both accurate and lethal. Researchers believe that repeated exposure to mediated violence can lead to anxiety and fear, acceptance of violence as an appropriate means of solving conflict, and desensitization, with resulting increases in aggression and decreases in altruism. In particular, the portrayal of justifiable violence that is common in American media—â€Å"good guys versus bad guys†Ã¢â‚¬â€places children at risk because it is so powerfully reinforcing. The relationship between media violence and real-life aggression is nearly as strong as the impact of cigarette smoking on lung cancer not everyone who smokes will get lung cancer, and not everyone who views media violence will become aggressive themselves. However, the connection is significant. The most problematic forms of media violence include attractive and unpunished perpetrators, no harm to victims, realism, and humor. SexResearchers investigating the impact of exposure to sexual content in media on adolescent sexual beliefs and early sexual initiation have found modest but significant associations, particularly in the realm of pornography. In a national sample of 1500 10- to 17-year-olds, nearly half of the Internet users had been exposed to on-line pornography in the prev ious year. In a sample of middle-school youth, exposure to sexually explicit (X-rated) content predicted perpetration of sexual harassment (for males), more permissive sexual norms, having oral sex, and engaging in sexual intercourse while in high school.Longitudinal studies now exist that have linked heavy exposure to sexual content in mainstream media with more rapid progression of sexual activity, earlier coital behavior, greater risk for and unplanned pregnancy, and sexually transmitted disease. One explanation for this relationship may lie in the role of the media as a â€Å"superpeer† that gives adolescent audiences a consistent message that sex is normative and risk free. In addition, media play an important role in providing sexual information to adolescents in the United States and in shaping their beliefs about how males and females behave in romantic relationships.Television shows geared toward teenagers actually have more sexual content than adult-oriented shows, yet there is little mention of the need for contraception or for responsibility. Virtually every Western country makes birth control available to adolescents, including allowing birth control advertisements in the media, but the major US television networks balk at airing ads for contraception. This flies in the face of the fact that a substantial body of evidence shows that giving teenagers’ access to condoms does not lead to earlier sexual activity.Parents and child advocates often express concern over children connecting with strangers on-line. Although there have been disturbing cases of Internet sexual predatory activity by adults on children, most recent studies of Internet safety have suggested that sexual solicitation of minors is more likely to occur by other minors. Social networking sites such as MySpace and Facebook enable adolescents to present themselves publicly, sometimes in very sexually suggestive ways; however, adult on-line predators are not using social n etworking sites to find or entice their victims.One national survey of â€Å"sexing† with cell phones, conducted with 13- to 19-year-olds, revealed that 20% had sent and 48% had received sexual messages. However, social networking sites can also be used prosocially for safer-sex campaigns, for example. Substance Use In the United States, more than $22 billion is spent marketing and advertising drugs ($13 billion on tobacco, $5 billion on alcohol, and $4 billion on prescription drugs), and many research studies have shown that it has a significant impact on adolescent use.Children and teenagers can also see considerable alcohol and drug content in on-line videos. Recent studies of social networking sites have found that substance abuse is referenced in 40% of the profiles. Portrayals of tobacco are also prevalent in the movies: ? 70% of movies made in the United States today contains smoking, and smoking is rarely associated with negative health outcomes. Longitudinal prospect ive studies have revealed that exposure to movie smoking at baseline (grades 5–8) predicts smoking initiation 1 to 8 years later.Experimental research has helped illuminate why exposure to movie characters' smoking is associated with smoking initiation: viewers who identify with the storyline and the characters are more likely to increase their intention to smoke. Obesity and Eating Disorders Numerous American and international longitudinal studies (one of them as long as 26 years in duration) have shown that media use is contributing to the current epidemic of obesity worldwide. However, the mechanism for why heavy television-viewing, in particular, is predictive of children's weight status is unclear. Food marketing may be 1 culprit.Children and teenagers see 4400–7600 ads per year for junk food and fast food on television alone. Randomized, controlled experiments have provided evidence that exposure to junk food advertising has an impact on children's food beliefs a nd preferences. The Internet now presents a new concern. As the Kaiser Foundation noted, â€Å"There is a vast amount of food related content online, with the potential to significantly expand and deepen children's exposure to food marketing messages. Apart from the influence of advertising, eating while viewing may lead to greater food consumption.College-aged students showed significantly greater consumption of food when subjects were watching television versus listening to classical music. The investigators hypothesized that satiety cues are suppressed in viewing conditions. Although the evidence that television-viewing displaces physical activity is equivocal, researchers are now examining whether heavy media use, particularly at nighttime, displaces sleep. Children who do not get enough sleep are more likely to engage in sedentary behaviors (such as television-viewing) and less likely to engage in physical activity.The media play a crucial role in the formation of body self-im age and may be responsible for creating unrealistic expectations and body dissatisfaction. Females who are regular readers of fashion and beauty magazines in early adolescence are more likely to suffer from a distorted body image during their teenaged years. A natural field experiment in Fiji revealed that the prevalence of eating disorders increased dramatically after the introduction of American television programs, which show excessively thin female lead characters.On the Internet, there are now ;100 proanorexia Web sites that not only encourage disordered eating but offer specific advice on purging, severely restricting caloric intake, and exercising excessively. School Performance and Learning Problems The possibility of a connection between television-viewing and ADD or other learning disabilities is currently an issue of great controversy. An initial study in 2004 revealed an association between daily hours of television-viewing at the ages of 1 to 2 years and subsequent atte ntional problems at the age of 7.However, a more recent study in which 59 children with ADD and 106 comparison children were examined actually revealed that the latter had more impairment in their cognitive processes after viewing television than the former. At least 4 studies have shown an impact on academic performance, especially if there is a television set in the child's or teenager's bedroom. Other Health Effects Heavy television-viewing has also been associated with hypercholesterolemia, hypertension, an increased prevalence of asthma, sleep disorders, mood disorders, psychological distress, and depression.These were largely correlational studies and, therefore, did not necessarily show cause and effect. Prosocial Effects Despite the negative effects listed above, the media can be powerfully prosocial and educational. Children and teenagers can learn antiviolence attitudes, empathy, tolerance toward people of other races and ethnicities, and respect for their elders. Video ga mes can be beneficial as well, including improving compliance with chemotherapy regimens in adolescents with cancer.Important and useful public messages can be successfully embedded into primetime television shows that are popular with adolescents. In an episode of the television program Friends, for example, Rachel tells her boyfriend Ross that she is pregnant although they had used a condom. A national telephone survey conducted with Friends viewers after the episode aired found that adolescents learned that condoms are not fool-proof and were more likely to discuss contraception with their parents.Similarly, a recent episode of Gray's Anatomy was effective in teaching viewers about HIV and pregnancy. Research into the impact of digital media on relationship formation and maintenance has revealed that on-line communication and on-line self-disclosure can stimulate adolescents' social connectedness and, thereby, their well-being. However, the benefits of socializing on-line are not equal for every child or adolescent. The positive Internet effect holds only when adolescents predominantly talk with their existing friends.Communication technologies that are most often used to communicate with strangers (eg, chat in a public chat room) or more solitary forms of Internet use (such as surfing the Web) have negative effects on social connectedness. TRADITIONAL MEDIA AND NEW MEDIA Children and adolescents spend more time with media than they do in any other activity except for sleeping—an average of ;7 hours/day. Children's bedrooms are replete with media technology: by 2005, two thirds had a television set, one half had a VCR or DVD player or video-game console, and nearly one third had Internet access or a computer.Media impact is increased significantly with the presence of a bedroom television: viewing increases 1 to 2 hours/day, risk of overweight increases by 31%, and the likelihood of smoking doubles. When a television is in the bedroom, parents are le ss able to monitor viewing habits , children participate in fewer activities such as reading and hobbies, and sleep is shortened Field Observation: Focus group: One of the aims of my research paper was to understand what children feel about the way they are affected by the Digital media. To do this i used one of our qualitative methods – focus group.A focus group is a method that is used by researchers to find out what people’s opinions and views are. During a focus group the researcher(s) will ask questions to stimulate discussion within the group, while taking note of what people are saying about particular issues. The focus group were conducted in Notre dame college-lwaize in total, 10 young people (5 males and 5 females) took part, who were all aged between 9 – 12year. Question asked during the focus group: * Do Digital media take a lot of your time? * Do you feel lost when you are not connected? Do you go online to check for new updates? * Do you feel you a lways have to go online to learn/view information? * Do you forget to eat when you are connected? * Do you use online social networking to retrieve any type of information? * Does spending time on social networking affects on your grades in a negative way? * Do you think you can stop yourself from always connecting online? * Are you unable to continue your day without checking for updates of news / friends online? * Has social networking sites made you become depressed? Do you enter sexual websites? * Do you talk with stranger people online? Analysis: After the focus groups were done, the information was analyzed and i was able to put together the information to have a basic result. I can say that each person had his/her own view, the information was not possible to evaluate and conduct on a percentage scale. The focus group study it showed that the males spend more time on social networking sites then men. They believe they do spend more time online which allows them to play ad ent er many kind of websites.All participants believe online social networking is time consuming and has its negatives. Some of the negatives given about online social networking. Some positives were: it has allowed a number of people to be curious to want to know more information, to learn more, to be able to communicate with people in different countries and be entertained. Solution and recommendation: Parents should limit total screen time for children older than 2 years to no more than 1 to 2 hours/day, and avoid screen time for children younger than 2 years.Also keep children's bedrooms free of screen media; and co-view media with their children and discuss the content.. Parents also need to avoid exposing young children to PG-13– and R-rated movies, given the prevalence of violent and sexual content in higher-rated film sand the new evidence that movie scenes that depict drinking alcohol and smoking may be very influential in teenagers' decisions to use alcohol and tobacco. In addition, parents can be mindful of their own media practices, because studies have shown that the strongest predictor of children's heavy media use is parents' heavy media use.Parental efforts to interpret, elaborate, and provide supplemental information on topics introduced by television have been found to be successful in countering negative or harmful content. In a recent study on exposure to sexual media content, adolescents who report that they discuss the content of what they see on television are less likely to engage in risky sexual activity. Moreover, Schools have not kept pace with modern media, especially in violence prevention, drug prevention, and sex education programs.With the amount of sexual suggestiveness currently displayed on television and in movies, schools no longer have any excuse for not providing comprehensive school-based sex education programs for children and adolescents, including full discussions of contraception and discussions of how sex and sex uality are portrayed in the media. Similarly, drug education programs must progress beyond scare tactics to incorporate principles of media education, teaching young people how to deconstruct alcohol and tobacco ads and, therefore, become more resilient.Conclusion: During the past 50 years, thousands of research studies have revealed that the media can be a powerful teacher of children and adolescents and have a profound impact on their health. To date, too little has been done by parents, health care practitioners, schools, the entertainment industry, or the government to protect children and adolescents from harmful media effects and to maximize the powerfully prosocial aspects of modern media. More research is needed, but sufficient data exist to warrant both concern and increased action. Digital Media Introduction: You may have heard of digital media, but you may have no idea what it is and how it can help you out when it comes to marketing. It's definitely important that you get up to speed so you can use this to benefit your business. Basically digital media refers to any type of electronic media out there. Today media can be accessed in many ways, including with hand held devices like mobile phones, laptops, desktops, mp3 players, and more. Digital media must be stored in an electronic way, so there is a lot of digital content on the internet today, including text content, pictures, audio content, as well as video content.Through the history of internet, digital media has been developing in various ways. Here's we'll take a look at how it has affected the Internet and ways that it may be integrated moving forwards (Rogers 2006). One type of digital media is text; this in fact represented the very first explosion of  this  type of content  out there on the Internet. When t he Internet first got big, there was an explosion of content on the web, especially with all the text editors and word processing options out there today (Rogers 2006).Larger companies started to put date on computers instead of storing it in cabinets, and the internet definitely allowed a great way to share, transfer, and store content as well. As the Internet grew, images began to appear. Instead of just text emails, soon people could send photos, and soon photo sites for sharing photos began to pop up. Then in the middle 1990s, audio began to become an important part of digital media with the mp3 files that could be easily used. Soon music and more was shared online with sites that allowed you to share audio.Last in the digital media development was video. YouTube definitely made video sharing a hugely popular form of modern media distribution and this is continuing to grow as we speak today. Now with new technology seen in things like the iPhone,  this new form of virtual medi a  is available in handheld devices as well, and no doubt  this sector  is only going to continue to grow in the future (Rogers 2006). Now that you understand a bit more about the technology side, you may be wondering how it can help your business.Well businesses are using digital media for marketing more and more today, realizing that there is a huge marketing field out there and that  it can help to draw in visitors and can even provide better search engine visibility with you. Text content can be kept updated on your site and helpful content is a great part of good marketing. Expertise in your field can really help your business and get traffic flowing into your business website. Photos, charts, diagrams, and models are always popular online and will help you to get more visibility as well.Audio allows you to use music on pages or to do podcasts for your business. Creating videos is a popular method of digital media marketing today, and videos do very well in search engin es (Rogers 2006). With the popularity of digital media, it is definitely important that you continue to create and use it for good marketing and business results. Even if you have to hire someone to help out, the benefits will make it worth the money. So knowing about and using digital media is definitely important for your business success todayProblem statement: Most people accept the idea that the media can influence people. But the degree of that influence, as well as who is most-impacted, when, how and why, have been the subjects of great debate among communication scholars for nearly a century. Media effects refers to the many ways individuals and society may be influenced by both news and entertainment mass media, including film, television, radio, newspapers, books, magazines, websites, video games, and music.To understand digital media effects, it is first critical to consider how media are used and for what purposes. Communication scholars have traditionally fallen into tw o camps – functionalists, who believe the media audience tends to be in control and active, and critical/culturalists who believe the audience has less control and is therefore more passive. The balance may lie somewhere in the middle and may vary from country to country. Purpose of the study: In this paper we are going to study and evaluate the digital media and its effect on children in general.The following text is a general idea: Youth spend an average of ;7 hours/day using media and the vast majority of them have access to a bedroom television, computer, the Internet, a video-game console, and a cell phone. In this paper we review the most recent research on the effects of media on the behavior and health and well-being of children and adolescents. Studies have shown that media can provide information about safe health practices and can foster social connectedness.However, recent evidence raises concerns about media's effects on aggression, sexual behavior, substance use , disordered eating, and academic difficulties. We provide recommendations for parents, practitioners, the media, and policy makers, among others, for ways to increase the benefits and reduce the harm that media can have for the developing child and for adolescents. More than 50 years of media research attests to the significant influence of media on child and adolescent health.Both â€Å"old† media (television, movies, magazines) and â€Å"new† media (the Internet and social networking sites, video/computer games, cell phones) can have an impact on virtually every health concern that practitioners and parents have about young people, including aggressive behavior, risky sexual behavior, substance use, and disordered eating. Although the media are not the leading cause of any of these problems, the research reviewed here suggests that they are significant.Yet, despite the evidence of potential harm, there is also evidence that media can be beneficial for youth (eg, by increasing empathy and acceptance of diversity through modeling of prosocial behaviors and developing children's early literacy skills through educational programming). Those concerned with child and adolescent health need to be aware of the research on the effects of modern media on youth. Theoretical framework: Literature review: Media affect youth not only by displacing time they spend doing homework or sleeping but also by influencing beliefs and behaviors.According to social learning theory, children and adolescents learn by observing and imitating what they see on the screen, particularly when these behaviors seem realistic or are rewarded. Cognitive development theory asserts that children's cognitive capacities at different stages determine if and how they understand media content. For example, children younger than 8 years who are not yet able to comprehend persuasive intent will be more vulnerable to advertising.In addition, media present youth with common â€Å"scriptsâ €  for how to behave in unfamiliar situations such as romantic relationships. Finally, superpeer theory states that the media are like powerful best friends in sometimes making risky behaviors seem like normative behavior. With the variety of theories suggesting a potentially powerful effect of the media and the growing empirical evidence for negative impact, one might hypothesize that parents would take care to limit exposure to detrimental media content.However, the â€Å"third-person effect† (a well-documented phenomenon in the communications literature) shows that teenagers and adults think that the media influence everyone except themselves or their children Violence and Aggression By the age of 18, the average adolescent will have seen an estimated 200 000 acts of violence on television alone. Much of the violence on television and in movies is presented in a sanitized and glamorized fashion, and in children's programming it often is presented as humorous.More than 1 0% of 10- to 14-year-olds saw 40 of the most violent movies in 2003. Both music videos and rap music have become increasingly violent. Interactive media can encourage antisocial beliefs and behavior in children and adolescents, particularly because violence in new media has been found to be prevalent as well. A recent analysis of video games revealed that more than half of all games contain violence, including ;90% rated as appropriate for children aged 10 years and older.Health professionals worry most about first-person shooter video games. In the aftermath of the West Paducah, KY school shooting, it was discovered that the shooter had never fired a real gun in his life before that day, yet his marksmanship was both accurate and lethal. Researchers believe that repeated exposure to mediated violence can lead to anxiety and fear, acceptance of violence as an appropriate means of solving conflict, and desensitization, with resulting increases in aggression and decreases in altruism. In particular, the portrayal of justifiable violence that is common in American media—â€Å"good guys versus bad guys†Ã¢â‚¬â€places children at risk because it is so powerfully reinforcing. The relationship between media violence and real-life aggression is nearly as strong as the impact of cigarette smoking on lung cancer not everyone who smokes will get lung cancer, and not everyone who views media violence will become aggressive themselves. However, the connection is significant. The most problematic forms of media violence include attractive and unpunished perpetrators, no harm to victims, realism, and humor. SexResearchers investigating the impact of exposure to sexual content in media on adolescent sexual beliefs and early sexual initiation have found modest but significant associations, particularly in the realm of pornography. In a national sample of 1500 10- to 17-year-olds, nearly half of the Internet users had been exposed to on-line pornography in the prev ious year. In a sample of middle-school youth, exposure to sexually explicit (X-rated) content predicted perpetration of sexual harassment (for males), more permissive sexual norms, having oral sex, and engaging in sexual intercourse while in high school.Longitudinal studies now exist that have linked heavy exposure to sexual content in mainstream media with more rapid progression of sexual activity, earlier coital behavior, greater risk for and unplanned pregnancy, and sexually transmitted disease. One explanation for this relationship may lie in the role of the media as a â€Å"superpeer† that gives adolescent audiences a consistent message that sex is normative and risk free. In addition, media play an important role in providing sexual information to adolescents in the United States and in shaping their beliefs about how males and females behave in romantic relationships.Television shows geared toward teenagers actually have more sexual content than adult-oriented shows, yet there is little mention of the need for contraception or for responsibility. Virtually every Western country makes birth control available to adolescents, including allowing birth control advertisements in the media, but the major US television networks balk at airing ads for contraception. This flies in the face of the fact that a substantial body of evidence shows that giving teenagers’ access to condoms does not lead to earlier sexual activity.Parents and child advocates often express concern over children connecting with strangers on-line. Although there have been disturbing cases of Internet sexual predatory activity by adults on children, most recent studies of Internet safety have suggested that sexual solicitation of minors is more likely to occur by other minors. Social networking sites such as MySpace and Facebook enable adolescents to present themselves publicly, sometimes in very sexually suggestive ways; however, adult on-line predators are not using social n etworking sites to find or entice their victims.One national survey of â€Å"sexing† with cell phones, conducted with 13- to 19-year-olds, revealed that 20% had sent and 48% had received sexual messages. However, social networking sites can also be used prosocially for safer-sex campaigns, for example. Substance Use In the United States, more than $22 billion is spent marketing and advertising drugs ($13 billion on tobacco, $5 billion on alcohol, and $4 billion on prescription drugs), and many research studies have shown that it has a significant impact on adolescent use.Children and teenagers can also see considerable alcohol and drug content in on-line videos. Recent studies of social networking sites have found that substance abuse is referenced in 40% of the profiles. Portrayals of tobacco are also prevalent in the movies: ? 70% of movies made in the United States today contains smoking, and smoking is rarely associated with negative health outcomes. Longitudinal prospect ive studies have revealed that exposure to movie smoking at baseline (grades 5–8) predicts smoking initiation 1 to 8 years later.Experimental research has helped illuminate why exposure to movie characters' smoking is associated with smoking initiation: viewers who identify with the storyline and the characters are more likely to increase their intention to smoke. Obesity and Eating Disorders Numerous American and international longitudinal studies (one of them as long as 26 years in duration) have shown that media use is contributing to the current epidemic of obesity worldwide. However, the mechanism for why heavy television-viewing, in particular, is predictive of children's weight status is unclear. Food marketing may be 1 culprit.Children and teenagers see 4400–7600 ads per year for junk food and fast food on television alone. Randomized, controlled experiments have provided evidence that exposure to junk food advertising has an impact on children's food beliefs a nd preferences. The Internet now presents a new concern. As the Kaiser Foundation noted, â€Å"There is a vast amount of food related content online, with the potential to significantly expand and deepen children's exposure to food marketing messages. Apart from the influence of advertising, eating while viewing may lead to greater food consumption.College-aged students showed significantly greater consumption of food when subjects were watching television versus listening to classical music. The investigators hypothesized that satiety cues are suppressed in viewing conditions. Although the evidence that television-viewing displaces physical activity is equivocal, researchers are now examining whether heavy media use, particularly at nighttime, displaces sleep. Children who do not get enough sleep are more likely to engage in sedentary behaviors (such as television-viewing) and less likely to engage in physical activity.The media play a crucial role in the formation of body self-im age and may be responsible for creating unrealistic expectations and body dissatisfaction. Females who are regular readers of fashion and beauty magazines in early adolescence are more likely to suffer from a distorted body image during their teenaged years. A natural field experiment in Fiji revealed that the prevalence of eating disorders increased dramatically after the introduction of American television programs, which show excessively thin female lead characters.On the Internet, there are now ;100 proanorexia Web sites that not only encourage disordered eating but offer specific advice on purging, severely restricting caloric intake, and exercising excessively. School Performance and Learning Problems The possibility of a connection between television-viewing and ADD or other learning disabilities is currently an issue of great controversy. An initial study in 2004 revealed an association between daily hours of television-viewing at the ages of 1 to 2 years and subsequent atte ntional problems at the age of 7.However, a more recent study in which 59 children with ADD and 106 comparison children were examined actually revealed that the latter had more impairment in their cognitive processes after viewing television than the former. At least 4 studies have shown an impact on academic performance, especially if there is a television set in the child's or teenager's bedroom. Other Health Effects Heavy television-viewing has also been associated with hypercholesterolemia, hypertension, an increased prevalence of asthma, sleep disorders, mood disorders, psychological distress, and depression.These were largely correlational studies and, therefore, did not necessarily show cause and effect. Prosocial Effects Despite the negative effects listed above, the media can be powerfully prosocial and educational. Children and teenagers can learn antiviolence attitudes, empathy, tolerance toward people of other races and ethnicities, and respect for their elders. Video ga mes can be beneficial as well, including improving compliance with chemotherapy regimens in adolescents with cancer.Important and useful public messages can be successfully embedded into primetime television shows that are popular with adolescents. In an episode of the television program Friends, for example, Rachel tells her boyfriend Ross that she is pregnant although they had used a condom. A national telephone survey conducted with Friends viewers after the episode aired found that adolescents learned that condoms are not fool-proof and were more likely to discuss contraception with their parents.Similarly, a recent episode of Gray's Anatomy was effective in teaching viewers about HIV and pregnancy. Research into the impact of digital media on relationship formation and maintenance has revealed that on-line communication and on-line self-disclosure can stimulate adolescents' social connectedness and, thereby, their well-being. However, the benefits of socializing on-line are not equal for every child or adolescent. The positive Internet effect holds only when adolescents predominantly talk with their existing friends.Communication technologies that are most often used to communicate with strangers (eg, chat in a public chat room) or more solitary forms of Internet use (such as surfing the Web) have negative effects on social connectedness. TRADITIONAL MEDIA AND NEW MEDIA Children and adolescents spend more time with media than they do in any other activity except for sleeping—an average of ;7 hours/day. Children's bedrooms are replete with media technology: by 2005, two thirds had a television set, one half had a VCR or DVD player or video-game console, and nearly one third had Internet access or a computer.Media impact is increased significantly with the presence of a bedroom television: viewing increases 1 to 2 hours/day, risk of overweight increases by 31%, and the likelihood of smoking doubles. When a television is in the bedroom, parents are le ss able to monitor viewing habits , children participate in fewer activities such as reading and hobbies, and sleep is shortened Field Observation: Focus group: One of the aims of my research paper was to understand what children feel about the way they are affected by the Digital media. To do this i used one of our qualitative methods – focus group.A focus group is a method that is used by researchers to find out what people’s opinions and views are. During a focus group the researcher(s) will ask questions to stimulate discussion within the group, while taking note of what people are saying about particular issues. The focus group were conducted in Notre dame college-lwaize in total, 10 young people (5 males and 5 females) took part, who were all aged between 9 – 12year. Question asked during the focus group: * Do Digital media take a lot of your time? * Do you feel lost when you are not connected? Do you go online to check for new updates? * Do you feel you a lways have to go online to learn/view information? * Do you forget to eat when you are connected? * Do you use online social networking to retrieve any type of information? * Does spending time on social networking affects on your grades in a negative way? * Do you think you can stop yourself from always connecting online? * Are you unable to continue your day without checking for updates of news / friends online? * Has social networking sites made you become depressed? Do you enter sexual websites? * Do you talk with stranger people online? Analysis: After the focus groups were done, the information was analyzed and i was able to put together the information to have a basic result. I can say that each person had his/her own view, the information was not possible to evaluate and conduct on a percentage scale. The focus group study it showed that the males spend more time on social networking sites then men. They believe they do spend more time online which allows them to play ad ent er many kind of websites.All participants believe online social networking is time consuming and has its negatives. Some of the negatives given about online social networking. Some positives were: it has allowed a number of people to be curious to want to know more information, to learn more, to be able to communicate with people in different countries and be entertained. Solution and recommendation: Parents should limit total screen time for children older than 2 years to no more than 1 to 2 hours/day, and avoid screen time for children younger than 2 years.Also keep children's bedrooms free of screen media; and co-view media with their children and discuss the content.. Parents also need to avoid exposing young children to PG-13– and R-rated movies, given the prevalence of violent and sexual content in higher-rated film sand the new evidence that movie scenes that depict drinking alcohol and smoking may be very influential in teenagers' decisions to use alcohol and tobacco. In addition, parents can be mindful of their own media practices, because studies have shown that the strongest predictor of children's heavy media use is parents' heavy media use.Parental efforts to interpret, elaborate, and provide supplemental information on topics introduced by television have been found to be successful in countering negative or harmful content. In a recent study on exposure to sexual media content, adolescents who report that they discuss the content of what they see on television are less likely to engage in risky sexual activity. Moreover, Schools have not kept pace with modern media, especially in violence prevention, drug prevention, and sex education programs.With the amount of sexual suggestiveness currently displayed on television and in movies, schools no longer have any excuse for not providing comprehensive school-based sex education programs for children and adolescents, including full discussions of contraception and discussions of how sex and sex uality are portrayed in the media. Similarly, drug education programs must progress beyond scare tactics to incorporate principles of media education, teaching young people how to deconstruct alcohol and tobacco ads and, therefore, become more resilient.Conclusion: During the past 50 years, thousands of research studies have revealed that the media can be a powerful teacher of children and adolescents and have a profound impact on their health. To date, too little has been done by parents, health care practitioners, schools, the entertainment industry, or the government to protect children and adolescents from harmful media effects and to maximize the powerfully prosocial aspects of modern media. More research is needed, but sufficient data exist to warrant both concern and increased action.