Tobacco Prevention free essay sample

Over the past 50 years America has increased its level of knowledge towards the use of tobacco as well as enhanced its cessation techniques through the use of medication and researched programs. Despite these advancements smoking has continued to be a detrimental problem to the American public. According to the CDC, about 1,000 persons younger than 18 years of age begin smoking on a daily basis. 1 Many of the cessation programs directed at youths are still young and creating names for themselves. As a result of all the research that has been done regarding the cessation programs for youths, three effective steps have been found. First, screen for tobacco dependency within families; second, educate parents about the dangers of smoking and second hand smoke and third, counsel and the use of prescription medication. While these three techniques have been proven to be effective they are not a 100% guarantee and they dont address the major issue of actually getting the youths themselves to the programs. We will write a custom essay sample on Tobacco Prevention or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Research has extensively documented the harms of tobacco to people, specifically youths but none of it has stopped the tobacco industry from creating advertisements intended for youths. According to the World Health Organization Tobacco companies must attract a new eneration of tobacco users to survive. The industry constantly loses customers because many current smokers quit smoking or die from tobacco-related diseases. As a result, tobacco companies develop massive marketing campaigns to entice youth to smoke and become long-term smokers. 2 To parents, teacher and politicians the youth are the future of our country, to tobacco companies; the youth are the future of their business and their needs for survival. The problem of youth smoking is one that we cannot ignore and must continue to attack. As a whole Healthcare professionals, overnment lobbyist groups, insurance companies and most important the youth themselves all must re-commit themselves to exterminate this persistent problem at hand. Out of the 4,000 chemicals found in cigarettes, nicotine is often referred to as the most dangerous one. It is not regarded as being incredible dangerous to someones health but is feared by many people because extremely addictive. When smoke is inhaled that contains nicotine, the nicotine reaches the brain in a mere six seconds. When used in small doses nicotine acts as a stimulant to the brain or a substance that raises the levels of physiological activity in the body. In large doses it acts as a depressant and hinders the current of signals in the nervous system. Those substances which we call drugs cause their effects by mimicking some substance that naturally occurs in the body or by interfering with some process which naturally goes on. Nicotine acts in the former manner, by mimicking a naturally occurring substance in the body. 3 The substance that nicotine imitates is the chemical neurotransmitter acetylcholine. Each neuron has a protein, which is called a receptor, when nicotine is inhaled they attach on to these receptors in the place of acetylcholine. When nicotine binds to these receptors, like any other drugs they cause changes in the body. The primary changes that occur in the body due to nicotine inhalation are increases in the blood pressure and heart rate. Nicotine also nas psychoactive ettects or m -altering ettect upon use. The release of dopamine during the use of nicotine is a major contributor to the drugs highly addictive qualities. Dopamine is a chemical neurotransmitter that is naturally released in the body during a pleasurable experience. The nicotine released when smoking cigarettes release dopamine leaving the smoker with the feeling of extreme leasure, resulting in the desire to feel that way often. The evil genius of this drug is that while it produces dopamine it impedes the production of monoamine oxidase, which is responsible for the natural process of breaking down dopamine. The ability for nicotine to block the production of monoamine oxidase wears off short after the end of use, this fact causes the smokers to continue to get the urge to smoke and feel heightened levels of dopamine. 4 Nicotine dependence is defined as an addiction to tobacco products caused by the drug nicotine, meaning you cant stop using the substance despite the knowledge hat is causing you harm. The united States Department of Health and Human Services have concluded that for most youths its takes 2-3 years to become nicotine dependent but as few as 100 cigarettes to become addicted. In 2010 about 2. 6 American adolescents (aged 12-17) reported using a tobacco product in the month prior to the survey. In that same year it was found that nearly 60 percent of new smokers were under the age of 18 when they first smoked a cigarette. Of smokers under the age of 18 more then 6 million will likely die prematurely from a smoking- related disease. 6 There are two primary influences that cau se adolescents to susceptible to developing nicotine dependence, the first being peer pressure. Peer pressure is a fact of life and inevitable in your childhood and adolescence. Wheatear a person is conscious or not towards the pressure the choices and behaviors peers make affect the surrounding peers. According to Phillip Morris USA youths with at least three friends who smoke are 10 times more likely pick up the habit than youths who have friends that do not smoke. 7 The other influence that causes adolescents to be more susceptible to nicotine ependence than adults is not a psychosocial factor but a biological one. There are biological differences in adults and adolescents that leave adolescents more vulnerable to nicotine addition. Much of the research done in this sector has been executed with the use of adolescent rats and adult rats for safety reasons. Adolescent rats are more susceptible to reinforcing effects of nicotine that adult rats, and take more nicotine when it is available than do adult animals. 8 An animal study done by the National Institute on Drug Abuse has reported the negative affects that acetaldehyde has on smokers, specifically adolescents. The study found that acetaldehyde, an organic chemical compound found in cigarettes dramatically increases the reinforcing properties of nicotine and may also contribute to tobacco addiction. It was also found that acetaldehyde has an age- related effect and was far more drastic in the adolescent animals brains than the adult animals. 9 In 2009 the Philadelphia Department of Health conducted a study that found the high school smoking rate was higher in Philadelphia then any other large city. The smoking rate for high school students was 3. %, the racial breakdown of those statistics were 1. % of African Americans, 3. 1% of Hispanics and 15. 6% of Caucasians. 10 There are two main contributors that lead Philadelphia to have the highest high school smoking rate; cigarettes are cheaper in Philadelphia then any other major city and the prevalence of tobacco retailers in Philadelphia, there are 27 retailers for every 1,000 youth between the ages 10-17. 11 Pennsylvania ranked 19th in the country for price of cigarettes with an average of 5. 85 per pack, about 5$ behind New York which was ranked 1st. 2 To formulate national statistics the CDC uses the data from the National Youth Tobacco Survey. The National Youth Tobacco Survey is our countries most effective way of measuring youth tobacco use. It is a school- based, self- administered questionnaire given to middle school students (6th to 8th grade) and high school students (9th- 12th grade). It has been given every 2 years since 2000 and is used by the Healthy People Foundation to keep track of the 2020 goal it has set. In 2011 the use of all types of tobacco for middle school and high school 7. 1% and 23. % respectively and the prevalence of specific cigarette use was 4. 3% for middle school students and 18. 1% for high school students. 13 The Healthy People oals for 2020 were set in 2009 when the cigarette use rate for high school students was at 19. 5%, the overall goal is to get it down to 16% by 2020. 14 In or der to reach the goals set for 2020 it is crucial that the countries cessation programs are doing their part. Research has shown that the most effective method for youths to quit smoking is a binary method, both behavioral techniques and medication use. In terms of medication use there are two types of medicinal categories, first- line and second- line. First-line medications are the ones that tend to be used first by smokers trying to quit and second-line medications are used if the irst- line medications prove inadequate. The most simplistic first-line medications are over-the-counter and come in the form of nicotine gum, patches and lozenges. The gums, patches and lozenges all offers doses of nicotine, starting with the highest dose the smoker is supposed to reduce dose over-time with the hopes of eventual nicotine independence. Nicotine Inhalers and Nicotine nasal spray are also first- line medications that work in the same way as the gum, lozenge and patch but are prescription rather then over-the-counter. Bupropion and Varenicline are two other forms of first-line medications that are also prescription. Bupropion also known as Zyban and Varenicline also known as Chantix both work to reduce the symptoms of nicotine withdrawal and reduce the urges smokers feel. The two second-line medications are Nortriptyline known as Aventyl and Clonidine known as Catapres. Aventyl is traditionally used to teat depression but has also proved successful with tobacco cessation efforts and Catapres is generally used to treat high blood pressue, but like Aventyl has shown effective in tobacco cessation. 1 5 The behavioral techniques that are used in tobacco cessation come in two forms, an intervention style and a program style. The current research efforts that have been done regarding the intervention methods of cessation are deficient. There is simply a lack of evidence- based interventions, which makes it very difficult to Judge the success as well as improve the programs. This issue was addressed with the Canadian Tobacco Control Research Initiative, which came up with the better practices model. The better practices model is based on the idea that successful solutions to complex problems must draw from both science and experience. 16 The Canadian Tobacco Control Research Initiative came out with guidelines on what ssues should be used while developing cessation interventions. As time passes with these new guidelines and more evidence based interventions occur it shouldnt ta long to specify what are the best methods for success. 6 Programs can be more accurately researched because their data is much more accessible. A cessation program can mean many different things, ranging from face to face counseling, telephone counseling, Internet counseling and group counseling. The most effective forms of counseling have been face-to-face counseling as well as group counseling. Telephone counseling is relatively new but has showed success in its short life. Rega rdless of how the counseling has been delivered the technique that has been proved to be the most effective is the problem-solving approach. The problem-solving approach asks smokers to think of times they are likely to smoke and then planning what to do to distract themselves from the urge to smoke. 17 Social support such as encouragement and caring has not surprisingly been proven effective ways to help cessation. N-O-T, Not on Tobacco is the American Lung Associations voluntary rogram for teens that want to quit smoking has proven to be successful in the past. It is the most researched, most widely used and most successful program in the United States. (YTC) N-O-T has 7 major characteristics that have made it to successful: 18 1. Allows teens to volunteer to participate 2. Includes group activities 3. Has separate activities for boys and girls 4. Uses a total health approach 5. Consists of 10 session and can be used in school and community settings 6. Is based on more then 10 years of research 7. Is proven effective, has a 21% quit rate, higher then any other program N-O-T evelops skills, confidence and support system that teenagers need in order to quit. They understand that one of the keys to quitting smoking is to have the ability to keep your life the same without the use of cigarettes. By doing this and aiding the teens in other problems other then the smoking such as controlling weight after quitting and managing stress they have been successful. While there has been success in the cessation programs there is clearly an incredible amount of room for improvement. The most effective way to drastically improve success is creating a more accessible environment to programs. Although many youth think about and attempt to quit tobacco many are unaware of or unable to access cessation services. Also, many youth do not think quitting tobacco is difficult enough to warrant professional assistance. 19 The most important thing we can do moving forward is to better recruit youth who smoke and use tobacco. Recruiting for programs such as these should be very specific and focus are the target audience. Using the data from the National Youth Tobacco Survey it can be fgured out which ethnicity has the most smokers and recruitment techniques should be in accordance ith those number . An effective way to do this would be to tap in to previous existing social networks in a community, such as a club or a sports team. While your peers can be the reason you start smoking as a result of negative pressure they can also be the reason you quit as a result of positive pressure. Offering incentives can also be a useful technique for recruitment, offering something like pizza at meetings could raise the attendance and access. Even if the child goes into the meeting with the sole intent of getting the incentive they are still exposed to cessation efforts. One last ecruitment technique can be to use other teens as recruiters. It will give a more personalized appearance and give you the feeling that you will not be alone. It is also on the shoulders of the health insurance companies and the health care system to provide access to these youths. All health insurance policies should cover any cessation program or method used by teens to quit smoking, the high prices of some medications and some counseling practices can deter youths from making an attempt to quit. It should be the standard that all health care services monitor and care for nicotine dependency. It falls on a combination of the government, healthcare systems and public health agencies to formulate a system that can effectively treat youth nicotine dependence. It is also extremely important that high schools are smoke free; the majority of youths time is spent, as schools and creating a smoke- free environment will deter smoking amongst youth. Another way to improve the current youth cessation programs in to apply adult programs to youth specifically for interventions, the most lacking in research of all methods. Due to this lack of research on youth interventions we can use what has been proven effective with adults. The United States Public Health System has provided the public specifically adults with recommendations that have proved successful. These recommendations include: It is essential that clinicians and health care delivery systems consistently identify and document tobacco use status and treat every tobacco user seen in a health care setting, Telephone quitline counseling is effective with diverse populations and has broad reach. Therefore, clinicians and health care delivery systems should both ensure patient access to quitlines and promote quitline use along with eight other proven effective recommendations. 0 As spoken about previously there are biological differences are one of the many things that vary between youth and adults. These differences could lead to a lack of success and should encourage counselors to use adult recommendations carefully. As a country we should be encouraged by the amount of success youth cessations programs have had but also motivated to continue to improve them. While it is unrealistic to think there will be a time when there are no smokers on this earth that should be our goal. We should aim for a 0% high school smoking rate because that will drive people to continue to find successful methods. If we live with the goal of a 0% smoking rate five or ten years down the road when we look at what the youth smoking is and look at its decline, it will be drastic. If you think about it in terms of a professional baseball pitcher, he goes into each game with the mindset of pitching a perfect game and works each day towards that goal. In hindsight with a more realistic mindset he can look back on his performance and see that getting 24 out of 27 men out rather then 27 out of 27 is still a success. Cessation is not an easy process and the only thing that can make it easier is a more committed effort by all parties involved.

Daughter, in Girl essays

The Relationship Between the Mother/Daughter, in Girl essays The relationship between the mother/daughter, in Girl, and father/son, in Reunion, are very different. In what way are they different? They are different because in the Girl, the mother is teaching her daughter the right way to live, the way to act. She is teaching her daughter morals, at a very young age. For example, the mother tells her daughter how to do laundry, wash the white clothes on Monday and put them on the stone heap; wash the colored clothes on Tuesday and put them on the clothesline to dry. And she is teaching her how to iron a shirt, how to set the table for tea or dinner. How to make medicine for a cold, or to get rid of an unwanted pregnancy. Also what she should do when she goes shopping for groceries, always squeeze the bread to make sure that its fresh. And the only thing the girl can answer is, what if the baker wont let me feel the bread? shes probably young and she doesnt fully grasp all that her mother is teaching her now. The reason why the mother is teaching her daughter at a young age so that when she grows up, she will come away with something. And people wont look at her like she has no moral values or they will look at her mother in a bad way, that she didnt teach her daughter anything. In the Reunion, the father is just a drunk who doesnt care about what people think of him. He says and does whatever he wants without a care in the world who he hurts or embarrasses. For example, when they went to a newsstand to get a newspaper, his father started talking to the clerk in a very rude manner, kind sir will you be good enough to favor me with one of your no good ten-cent afternoon papers? The clerk didnt want to deal with him so he just turned away, but Charlies father kept insisting on getting what...

Principles On Drug Abuse Treatment Research Paper

Principles On Drug Abuse Treatment - Research Paper Example According to Belenk, offenders need to provide urine tests on a regular basis. The court further assists offenders to secure entitlements such as medical, housing, or welfare allowance. Offenders need to visit probation officers on a frequent basis well as visit counseling sessions. However, drug courts are not effective in the treatment of drug-related cases. This is because such courts use coercive means, which offenders conform to for just some time. Drug offenders like programs that give them the chance to volunteer. Courts, however, have strict regulations and procedures, which is not effective. Rehabilitation centers that offer such services voluntarily serve better to offenders. Drug treatment as a routine is effective in reducing recidivism among offenders. These programs, however, take various forms. These treatments include the use of voluntary service centers such as rehabilitation stations. It may also take the form of mandatory treatment programs that include the use of the drug courts and law enforcement. Drug abuse leads to the loss in the national governments' funds. Funding such program costs lots of dollars. On the health of offenders, drug treatment saves offenders from mental health complications. Despite the success of drug success of drug treatment program, it faces several challenges. Such challenges include the unavailability of high-quality programs, the difference in priorities and the inability of such programs to benefit offenders after prison time.

Effectiveness of Risk Assessment in Preventing Pressure Ulcer Research Paper

Effectiveness of Risk Assessment in Preventing Pressure Ulcer - Research Paper Example The objective of the study will be as follows: To assess whether incorporating risk assessment in nursing practice can reduce the prevalence of pressure ulcers; Establish whether risk assessment can reduce the overall preventive measures used on a patient Investigate whether the detection of pressure ulcers in its early stages could reduce its severity and prevent other illnesses from developing. Background Pressure ulcers are local injuries to skin and/or underlying tissues due to pressure from an object pressing and/or rubbing against the skin. Pressure usually leads in insufficient blood flow and occurs mostly in bony areas such as the sacrum, coccyx, hips, and heels. Insufficient blood supply can lead to death of skin cells leading to the formation of an ulcer. In the US, the prevalence of pressure ulcers varies among states widely, with some states such as Ontario recording incidence rates of 53% in poorly managed healthcare institutions (Clarke, Bradley, & Whytock, 2005).... The staff will also be trained on early detection of the injuries. c) Comparison Data on patients at risk from developing pressure ulcer will be collected before and after training. The data will also include the number of patients who will develop ulcers over a four-week period before and after the training intervention. Data collected after nursing staff have undergone training will be compared to that collected before the training using various statistical analyses to determine whether there was a significant decline in the number of patients at risk of developing ulcers. d) Outcome Results of the analysis will also indicate whether training of nursing personnel in the assessment of pressure ulcer risk is effective in reducing the number of patients developing pressure ulcers. e) Time The study will run for a period of three months. Data on the number of patients developing ulcers and those at risk will be collected for a period of four weeks followed by training of personnel. Dat a will be collected again after training for a period of four weeks. Critique of Literature Clinical studies have shown that development of pressure ulcer during hospitalization can be alleviated by adopting appropriate mitigation measures (Severens, Hobraken, Duivenvoorden, & Frederiks, 2002; Vanderwee, Clark, Dealey, Gunningberg, & Defloor, 2007). These measures can include the development of methods and ways of determining risk factors. Early action can alleviate pain and improve quality of life among persons at risk or those already affected. Healthcare institutions can also benefit from early detection of pressure ulcers by reducing fiscal and time expenditure on the care and treatment of patients. Clarke et al. (2005) mention that pressure ulcers directly kill at least

Wireless Lan Applications Areas Computer Science Essay

Wireless Lan Applications Areas Computer Science Essay G. Marconi invented the wireless telegraph in 1896. In 1901, he sent telegraphic signals across the Atlantic Ocean from Cornwall to St. Johns Newfoundland; a distance of 1800 miles. His invention allowed two parties to communicate by sending each other alphanumeric characters encoded in an analog signal. Over the last century, advances in wireless technologies have led to the radio, the television, the mobile telephone, and communication satellites. All types of information can now be sent to almost every corner of the world. Recently, a good attention has been focused on wireless networking. Early wireless LAN products, introduced in the late 1980s, were marketed as substitutes for traditional wired LANs. Wireless networking is allowing businesses to develop WANs, MANs, and LANs without cabling. A wireless LAN saves the cost of the installation of LAN cabling and eases the task of relocation and other modifications to network structure. The IEEE has developed 802.11 as a standard for wireless LANs. The Bluetooth industry consortium is also working to provide a seamless wireless networking technology. The impact of wireless communications has been and will continue to be profound. Very few inventions have been able to shrink the world in such a manner. The standards that define how wireless communication devices interact are quickly converging and soon will allow the creation of a global wireless network that will deliver a wide variety of services. 1.2 Over view As the name suggests, a wireless LAN is one that makes use of a wireless transmission medium. Until recently, wireless LANs were little used. The reasons for this included high prices, data rates, occupational safety concerns, and licensing requirements. As these problems have been now addressed, the popularity of wireless LANs has grown rapidly. 1.3 Wireless LAN Applications Areas: There are four application areas for wireless LANs: LAN extension, Cross- building interconnect, Nomadic access and Ad hoc networks. LAN Extension The motivation for wireless LANs was overtaken by events. First, as awareness of the need for LANs became greater, architects designed new buildings to include extensive pre wiring for data applications. Second, with advances in data transmission technology, there is an increasing reliance on twisted pair cabling for LANs and in particular, Category3 and Category 5 unshielded twisted pair. However, in some environments, there is a role for the wireless LAN as an alternative to a wired LAN. Examples include buildings with large open areas. In most of these cases, an organization will also have a wired LAN to support servers and some stationary workstations. Thus, this application area is referred to as LAN extension. There is a backbone wired LAN, such as Ethernet, that supports servers, workstations, and one or more bridges or routers to link with other networks. In addition, there is a Control Module (CM) that acts as an interface to a wireless LAN. The control module includes either bridge or router functionality to link the wireless LAN to the backbone. It includes some sort of access control logic, such as a polling or token-passing scheme, to regulate the access from the end systems. Cross- Building Interconnect Another use of wireless LAN technology is to connect LANs in nearby buildings, be they wired or wireless LANs. In this case, a point-to-point wireless link is used between two buildings. The devices so connected are typically bridges or routers. This single point-to-point link is not a LAN per se, but it is usual to include this application under the heading of wireless LAN. Nomadic Access Nomadic access provides a wireless link between a LAN hub and mobile data terminal equipped with an antenna, such as a laptop computer or notepad computer. Nomadic access is also useful in an extended environment such as a campus or a business operating out of a cluster of buildings. Ad Hoc Networking An ad hoc network is a peer-to-peer network (no centralized server) set up temporarily to meet some immediate need. For example, a group of employees, each with a laptop or palmtop computer may convene in a conference room for a business or classroom meeting. The employees link their computers in a temporary network just for the duration of the meeting. There are differences between a wireless LAN that supports LAN extension and nomadic access requirements and an ad hoc wireless LAN. In the former case, the wireless LAN forms a stationary infrastructure consisting of one or more cells with a control module for each cell. Within a cell, there may be a number of stationary end systems. Nomadic stations can move from one cell to another. In contrast, there is no infrastructure for an ad hoc network. Rather, a peer collection of stations within range of each other may dynamically configure themselves into a temporary network. Fig 1.1 Wireless LAN Configurations 1.4 Wireless LAN Requirements A wireless LAN must meet the same sort of requirements typical of any LAN, including high capacity, ability to cover short distances, full connectivity among attached stations, and broadcast capability. In addition, there are a number of requirements specific to the wireless LAN environment. The following are among the most important requirements for wireless LANs. Throughput: The medium access control protocol should make as efficient use as possible of the wireless medium to maximize capacity. Number of nodes: Wireless LANs may need to support hundreds of nodes across multiple cells. Connection to backbone LAN: In most cases, interconnection with stations on a wired backbone LAN is required. For infrastructure wireless LANs, this is easily accomplished through the use of control modules that connect to both types of LANs. There may also need to be accommodation for mobile users and ad hoc wireless networks. Service area: A typical coverage area for a wireless LAN has a diameter of 100 to 300m. Battery power consumption: Mobile workers use battery-powered workstations that need to have a long battery life when used with wireless adapters. This suggests that a MAC protocol that requires mobile nodes to monitor access points constantly or engage in frequent handshakes with a base station is inappropriate. Typical wireless LAN implementations have features to reduce power consumption while not using the network, such as a sleep mode. Transmission robustness and security: Unless properly designed, a wireless LAN may be interference prone and easily eavesdropped. The design of a wireless LAN must permit reliable transmission even in a noisy environment and should provide some level of security from eavesdropping. Collocated network operation: As Wireless LANs become more popular, it is quite likely for two or more wireless LANs to operate in the same area or in some area where interference between the LANs is possible. Such interferee may thwart the normal operation of a MAC algorithm and may allow unauthorized access to a particular LAN. License-free operation: Users would prefer to buy and operate wireless LAN products without having to secure a license for the frequency band used by the LAN. Handoff/roaming: The MAC protocol used in the wireless LAN should enable mobile stations to move from one cell to another. Dynamic configuration: The MAC addressing and network management aspects of the LAN should permit dynamic and automated addition, deletion, and relocation of end systems without disruption to other users. 1.5 The Trouble with Wireless Wireless is convenient and often less expensive to deploy than fixed services, but wireless is not perfect. There are limitations, political and technical difficulties that may ultimately prevent wireless technologies from reaching the other side with full potential. Two limiting issues are incompatible standards and device limitations. Device limitations also restrict the free flow of data. The small LCD on a mobile telephone is inadequate for displaying more than a few lines of text. In additions, most mobile wireless devices cannot access the vast majority of WWW sites on the Internet. The browsers use a special language, wireless markup language (WML), instead of the de facto standard HTML. Most likely, no one wireless device will be able to meet every need. The potential of wireless can be met but not with a single product. Wireless will succeed because it will be integrated into a variety of devices that can meet a variety of needs. 1.6 Fading in the Mobile Environment Perhaps the most challenging technical problem being faced by communication systems engineers is fading in a mobile environment. The term fading refers to the time variation of received signal power caused by changes in the transmission medium or path(s). In a fixed environment, fading is affected by changes in atmospheric conditions, such as rainfall. But in a mobile environment, where one of the two antennae is moving relative to the other, the relative location of various obstacles changes over time, creating complex transmission effects. 1.6.1 Types of Fading Fading effects in a mobile environment can be classified as either fast or slow. Referring to Fig 1.2, as the mobile unit moves down a street in an urban environment, rapid variations in signal strength occur over distances of about one-half a wavelength. The rapidly changing waveform is an example of the spatial variation of received signal amplitude. The changes of amplitude can be as much as 20 or 30 dB over a short distance. This type of rapidly changing fading phenomenon, known as fat fading, affects not only mobile devices in automobiles, but even a mobile phone user walking down an urban street. As the mobile user covers distances well in excess of a wavelength, the urban environment changes, as the user passes buildings of different heights, vacant lots, intersections, and so forth. Over these longer distances, there is a change in the average received power level about which the rapid fluctuations occur. This is referred to as slow fading. Lamp Post B D C A Fig 1.2 Mobile unit signal reflections Fading channel models are often used to model the effects of electromagnetic transmission of information over the air in cellular networks and broadcast communication. Fading channel models are also used in underwater acoustic communications to model the distortion caused by the water. Mathematically, fading is usually modeled as a time-varying random change in the amplitude and phase of the transmitted signal. 1.6.2 Slow vs. Fast Fading The terms slow and fast fading refer to the rate at which the magnitude and phase change imposed by the channel on the signal changes. The coherence time is a measure of the minimum time required for the magnitude change of the channel to become decorrelated from its previous value. Slow fading arises when the coherence time of the channel is large relative to the delay constraint of the channel. In this regime, the amplitude and phase change imposed by the channel can be considered roughly constant over the period of use. Slow fading can be caused by events such as shadowing, where a large obstruction such as a hill or large building obstructs the main signal path between the transmitter and the receiver. The amplitude change caused by shadowing is often modeled using a log-normal distribution with a standard deviation according to the Log Distance Path Loss Model. Fast Fading occurs when the coherence time of the channel is small relative to the delay constraint of the channel. In this regime, the amplitude and phase change imposed by the channel varies considerably over the period of use. In a fast-fading channel, the transmitter may take advantage of the variations in the channel conditions using time diversity to help increase robustness of the communication to a temporary deep fade. Although a deep fade may temporarily erase some of the information transmitted, use of an error-correcting code coupled with successfully transmitted bits during other time instances (interleaving) can allow for the erased bits to be recovered. In a slow-fading channel, it is not possible to use time diversity because the transmitter sees only a single realization of the channel within its delay constraint. A deep fade therefore lasts the entire duration of transmission and cannot be mitigated using coding. Flat vs. Frequency-selective Fading As the carrier frequency of a signal is varied, the magnitude of the change in amplitude will vary. The coherence bandwidth measures the minimum separation in frequency after which two signals will experience uncorrelated fading. In flat fading, the coherence bandwidth of the channel is larger than the bandwidth of the signal. Therefore, all frequency components of the signal will experience the same magnitude of fading. In frequency-selective fading, the coherence bandwidth of the channel is smaller than the bandwidth of the signal. Different frequency components of the signal therefore experience decorrelated fading. In a frequency-selective fading channel, since different frequency components of the signal are affected independently, it is highly unlikely that all parts of the signal will be simultaneously affected by a deep fade. Certain modulation schemes such as OFDM and CDMA are well-suited to employ frequency diversity to provide robustness to fading. OFDM divides the wideband signal into many slowly modulated narrowband subcarriers, each exposed to flat fading rather than frequency selective fading. This can be combated by means of error coding, simple equalization or adaptive bit loading. Inter-symbol interference is avoided by introducing a guard interval between the symbols. CDMA uses the Rake receiver to deal with each echo separately. Frequency-selective fading channels are also dispersive, in that the signal energy associated with each symbol is spread out in time. This causes transmitted symbols that are adjacent in time to interfere with each other. Equalizers are often deployed in such channels to compensate for the effects of the inter symbol interference. Fading effects can also be classified as flat or selective. Flat fading, or nonselective fading, is that type of fading in which all frequency components of the received signal fluctuate in the same proportions simultaneously. Selective fading affects unequally the different spectral components of a radio signal. The term selective fading is usually significant only relative to the bandwidth of the overall communications channel. If attenuation occurs over a portion of the bandwidth of the signal, the fading is considered to be selective; nonselective fading implies that the signal bandwidth of interest is narrower than, and completely covered by, the spectrum affected by the fading.

Women Online :: Internet Feminist Technology Essays

Women Online Is it better to be a woman online or a man online? Which sex is more respected? Do women have better conversations then men or is it the other way around? Can women participate in a debate with men and still be heard? Are women being treated equally online in comparison to their male counterparts? These are some of the questions that are asked in the articles of Dale Spender and Laura Miller. Dale Spenders article entitled Gender-Bending, and Laura Millers article entitled Women and Children First: Gender and the Settling of the Electronic Frontier. In which the two female authors give their opinions about the good side and bad side of being a woman online. In Dale Spenders article she describes how womens behaviors alter depending on if they are talking to a man or a woman. Their behaviors alter by the terms and tones they use to their posture/demeanor and weather or not eye contact is made. Spender observed such behavior in a study she preformed. When a man entered a conversation uninvited women would automatically give him the floor, as was to be expected. But what wasnt expected was that women would change the way they were sitting and they would look up to him rather then down. In another experiment a baby was handed to a group of women with its sex unidentified. When the sex was identified as a female the baby was held closely and tightly. The females heads were bent down and they spoke quietly and soothingly to the baby. When the women where told that a mistake was made that the baby was in fact a boy the behavior altered. At some points the baby was almost dropped when the women changed the way the baby was being held. The baby was held further away and was bounced up and down. The womens tone changed from soothing to loud and robust. The child was also raised to eye-level when talked to. Even in the case of babies Spender believes that all of our words, actions, and body language are gender-loaded(71). She believes that only when we know the sex of who we are talking to can we actually conduct a conversation. Due to these studies and experiments Spender came to the conclusion that the only way to gain respect is to be a man. Not only when we are young but in writing and conversation.

Environmental Experiences Essay

The capability of a location to enhance environmental experience depends on the landscape and its potential to foster and create subjective interpretations among individuals. These places also are significant to visitors since it promotes education and other indirect effects. Recognizing the need for architecture is important for people to fully understand and feel the landscape experience. The Tree Top Walk at the Valley of Giants in Australia â€Å"is a walkway that rises up to 38m above the forest. † Visitors can be able to create the feeling of environment. Visitors get a different perspective on the shapes, sounds and movement of the forest. The Oregon Paleo Lands Institute will help you discover Oregon’s past and explore its present landscapes. The place helps educate individuals and visitors of the wonders the place has to offer. Our mission is to help northwest residents and visitors of all ages to explore, understand, and enjoy the world-renowned natural history of north central Oregon, the ancient and living landscapes of Oregon’s last 400 million years, and the full fossil record of earth’s last 50 million years. The Lady Bird Johnson Wildflower Center in Texas seeks to inform individuals of the diverse native plants in the region. First as the National Wildflower Research Center and later as the Lady Bird Johnson Wildflower Center, this special place exists to introduce people to the beauty and diversity of wildflowers and other native plants. This is in response to the threats and the call for preservation of these plants. These places help enhance their experience of understanding landscape by how each one creates the feeling of satisfaction and cultivate the feeling of appreciation that contributes to the landscape experience. It must be a mixture of both understanding and at the same time appreciation of his/her perceptive abilities. However, an individual must not only settle for what is observable. The visitor must create and conceptualize his/her own interpretation of the landscape. This image will bear some relationship to the way in which the individual responds to and structures his world as a result of his physical perceptual capacities, socio-economic, cultural, personality, experiential and other characteristics. The three types of places mentioned give both direct and indirect experiences to the visitor. Looking at it, the area of indirect experiences is classified to be relative. An experience of an individual may vary depending on how each one perceives a landscape and associates it to personal experience. A person feeling can range from curiosity over the landscape to happiness and awe. There are varied reactions among people and this creates different reactions that cultivate experience. On the other hand, there are also direct experiences that the landscape contributes to a visitor. These are (1) education, (2) environmental education and (3) interpretative centers. Education can be considered as one important contributions of landscape experience. It creates awareness that has been stimulated by the actuality of perceiving, analyzing and understanding the landscape. A visitor creates its connection with the landscape by the way it manifests itself to the viewer and in return how the person responds to it given the factors that revolve around the environment and the individual. Thus, this creates the process of education for each visitor. Environmental education can also be seen as an outcome of landscape experience since the three examples that were given are primarily natural or ecological sites. Landscape experiences gives idea to visitors of the current situation of these sites. This experience creates awareness especially during this time that the call for environmental concern has been constantly increasing. Effective and meaningful environmental education is a challenge we must take seriously if we and future generations are to enjoy the benefits of our natural heritage. Thus, landscape experiences creates an avenue for environmental education by showcasing visitors the beauty and wonder of these sites and how each one is responsible for its protection and continued sustenance. The last mentioned is landscape experience creates interpretative centers. Landscape experience gives opportunities for interpretative centers to provide adequate information regarding the site. Also, interpretative centers provide cultivate interests of volunteers and organizations to further promote the site. Architecture plays an important role in landscape experience. People who have background in the topic understand that its facets are diversified. To fully appreciate architecture, students need to deconstruct its meaning from a variety of perspectives: artistic, social, and scientific. Architecture serves as a guide for visitors to engage in their local landscape. The idea is that each individual seeks find meaning and experience in the landscape however this cannot be done without an understanding architecture. Another is that architecture’ diversity and varied perspectives paves the way for an increased landscape experience among visitors. Different meanings and interpretations are derived from these sites that foster deeper learning experiences. There are many variants and factors that determine the landscape experience of an individual. The capability of an individual to associate the landscape with an understanding of architecture and different subjective interests’ can create a meaningful and worthwhile experience. The full appreciation of the environment experience again is achieved if a learning process is obtained by the individual upon exposure to the landscape.