Astronomy assignment 2 Essay Example | Topics and Well Written Essays - 750 words

Astronomy assignment 2 - Essay Example 1. Mass transfer or overflow – a process that could have occurred in a close binary system where one high-mass star beginning the end of its life expands and sheds off its outer gas to the other, originally a low-mass star, as a result of the latter’s gravitational pull. The originally low-mass star grows in size and becomes a high-mass star (Heggie & Hut 2003). Thus, Blue Stragglers have live longer than the usual high-mass star. 2. Collision theory – Collision could occur between single-binary or binary-binary stars encounters in a cluster which will produce a single body which will have a mass twice or more than that of the turn-off mass (Heggie & Hut2003. Bennett, Jeffrey and Megan Donahue, Nicholas Schneider and Mark Voit. The Cosmic Perspective, Fifth Edition. http://www.coursesmart.com/mycoursesmart?page=0&__myxmlid=9780321542632#X2ludGVybmFsX0Jvb2tJbmZvQWpheFBhbmVsP3BhZ2U9JnhtbGlkPTk3ODAzMjE1NDI2MzI= , pp 536, 566,

Communism Essay Example | Topics and Well Written Essays - 500 words

Communism - Essay Example Mixed results can also be found in one of our large trading partners, Chile. Until the beginning of the 20th century Cuba had been a Spanish Colony. Cuba was formally granted independence in 1903 and throughout the century Cuba fell under a series of radical and often corrupt regimes. In the 1950s Batista ruled Cuba with a strong dictatorship under the influence of Mafia corruption. Opposition to the Batista regime resulted in the overthrow of the government by Castro backed forces. Castro increasingly turned to communism as an ideology. Today, the per capita income is $3,000 per year, largely restricted by reduced trade opportunities ("Background Note: Cuba") Castro's popularity was severely tested by the aftermath of the Soviet collapse, which led to a cutoff in aid, the loss of a guaranteed export market for Cuban sugar and the loss of a source of cheap imported oil. Conditions in Cuba are indicated when Mantilla reports, " [...] a home with a washer and dryer would be a very rare home indeed". In Cuba, however, these events were not sufficient to persuade Cuban Communists that they should voluntarily give up power. General Pinochet Ugarte was head of the military council that ruled Chile from 1973 to 1990, which took control in a violent coup that overthrew the Socialist President Salvador Allende.

Fragile X Syndrome Case Study Health And Social Care Essay

Fragile X Syndrome Case Study Health And Social Care Essay From seven years old, Michaels speech was still rather incoherent, he spoke very quickly and under his breath and didnt make much eye contact. Only up until the last couple of years his speech has improved and is much clearer, although he still tends to perseverate and get stuck on a subject and repeat the same thing over and over. Michael has a sister 2 years older and in 1992 they were both referred to the genetics clinic in the Royal Childrens Hospital by our pediatrician as they both presented with significant developmental delays and the doctor suspected some genetic condition may be at the root of the problem. Tests were performed, even an X-ray on Michaels head as they noted he had rather dysmorphic features, but nothing proved positive and there was no known reason for their problems. ______________________________________________________________________________The patient presented in the above case study is a classic case of Fragile X-Syndrome, the most frequent cause of inherited mental retardation. Patients presenting with this syndrome are affected in various facets of functioning, including intellect, emotion, behavior, and physical characteristics. The cause of the syndrome involves the expansion of a single trinucleotide gene sequence on the X chromosome. Other disorders that are placed in this category include Huntingtons Disease, Kennedy Disease, Dentatorubralpallidoluysian atrophy, and Friedrichs ataxia. This consequently results in the failure to express a protein that is required for normal neural development, and coded by the FMR1 gene. Because it is an X-linked disorder, cases are seen in all carrier males and in 35% of carrier females. Because of the subtle nature of signs of the syndrome and difficulty in diagnosis, all children with mental retard ation should be tested for Fragile X syndrome and family members are advised to undergo genetic counseling in order to decrease the recurrence of Fragile X in the family. Etiology The abnormality of the chromosome presented in Fragile X syndrome is found on the Xq27.3 site and commonly used as a diagnostic marker for the syndrome [1]. In most cases, the expansion of the single trinucleotide gene sequence includes 50 to 200 CGG repeats at the site and these repeats are passed down from generation to generation [1]. In comparison, the number Mathew 2 of repeats in a normal individual is between 6 and 50. Due to the increasing expansion of the trinucleotide gene sequence, there is methylation of the DNA which in turn silences the FMR1 protein [3]. FMRP plays important roles in learning and memory, and also appears to be involved in development of axons, formation of synapses, and the wiring and development of neural circuits. Diagnosis Because there is no clinical diagnostic criteria, scoring systems have been developed to select individuals for Fragile X Syndrome [4]. It can also be diagnosed using molecular genetics testing of the FMR1 gene. One method of diagnosis is based on chromosomal study to present the chromosome under special folic acid deficient culture conditions [3]. There are two different types of molecular DNA tests. The screening tests are polymerase chain reaction based. Additionally, they need to be confirmed using Southern blot hybridization [5]. It is important to diagnose affected patients as early as possible to provide early intervention and supportive care (i.e., specific developmental therapy and an individualized education plan) and to inform parents for further family planning [4]. One half of families in a 2002 survey reported having an additional child with fragile X syndrome before the older affected child was diagnosed [4]. Family history collection should include questions about other family members, with particular attention to developmental delay, mental retardation, and psychiatric disorders [4]. In addition, a family history of women with premature ovarian failure and men with FXTAS should be ascertained. A positive family history in a proband with developmental delay should prompt consideration of genetic testing of the FMR1 gene [4]. The American College of Medical Genetics recommends testing, regardless of family history, for all males and females with mental retardation of unknown etiology [4]. Therapy/Treatment Treatment is supportive, requiring a multidisciplinary team and including anxiety-reducing measures, behavior modification, and medications to manage associated psychiatric disorders. Individual education plans are necessary for school-age children [2]. Although several Mathew 3 medications have been proposed to treat fragile X syndrome, none of them are supported by ]good evidence [2]. While there is no current cure for the syndrome, there is hope that further understanding of its underlying causes would lead to new therapies. Currently, the syndrome can be treated through behavioral therapy, special education, and when necessary, treatment of physical abnormalities [2]. Persons with the fragile X syndrome in their family histories are advised to seek genetic counseling, to assess the likelihood of having children who are affected, and how severe any impairments may be in affected descendants [2]. The Fragile X syndrome been the subject of numerous studies, and recent investigations have addressed the question of whether this disorder is amenable to either prenatal diagnosis or to treatment with folic acid [3]. In a previous study, the effect of oral folic acid therapy (10 mg/day) in a blind study of 14-year-old monozygous twins with the fragile X syndrome was examined [3]. They reported on eight patients with psychotic-like symptoms. Seven were improved by therapy with I M 5-formyltetrahydrofolate (folinic acid) at doses of 0.5 mg/kg body weight for a period of a few weeks [3]. Three patients had an almost total recovery from psychotic-like symptoms [3]. One 14-year-old boy who was severely hypotonic and disinterested in his environment became responsive and able to sit and crawl after 2 months of therapy with folic acid in doses of 1 mg/kg day [3]. Harpey also reported some success with therapy with intramuscular folinic acid and hydroxocobalamin by mouth [3]. In a recent re port, a male fetus was diagnosed as having fragile X and the mother was started on a regime of folic acid 2 mg/day [3]. After delivery, the baby was treated with 1 mg/day of folic acid. On evaluation at 6 weeks of age, the baby was described as having a dolicocephalic head, long ears, a flattened malar area, enlarged testes, and a high frequency of fragile X chromosomes (20/60 cells). Two studies attempted controlled trials of folate in the fragile X syndrome, and one of these has been reported in some detail [3]. Brown conducted a double-blind crossover study in which two brothers with the fragile X syndrome were treated with either intravenous folic acid (1.6 mg/kg daily as a single dose) or saline placebo for 8 days [3]. Following the controlled trial, the brothers were maintained on 10 mg/day of oral folic acid for 3 weeks. Over 6 weeks, the dose was increased to 500 mg/day for the younger brother and 1,000 mg/day for the older brother, and then both Mathew 4 brothers were maintained on 1,000 mg/day from 1 month to 5 months after the onset of the study [3]. Because this disorder is a very common cause of familial mental retardation, and because of the in vitro effect of folate in decreasing expression of the fragile site, one may be tempted to attempt folate therapy in these patients. However, two studies to date have failed to demonstrate any abnormality of folate metabolism in cultured cells from patients with the fragile X syndrome [5]. Therefore, we urge continued caution in the expectation of beneficial results and advise against routine use of folate therapy in patients with established mental retardation and the fragile X syndrome [5]. Because there is no cure for Fragile X syndrome, the hope is that future investigations into the underlying causes that will further lead to new therapies.

Dolomite and Peaty Wheat Straw Essay -- Film, Race

I have seen many from Dolomite and Peaty Wheat Straw by Rudy Ray Moore, Willy Dynamite starring Roscoe Orman, and The Mack Starring Max Julien and so on. The way these actors portrayed the characters of Willy Dynamite, Dolomite, and Goldie the way the talked the jive the way they walked the walk more than likely set the black race back by decades. Grabbing there groins and having a glide in their stride, wearing big hats, capes, and over exaggerated gestures help create stereotypes and threadbare ideals of the black race that are prevalent even today. In 1987, Robert Townsend wrote, starred, and directed a behind the scenes parody of those types of movies called Hollywood Shuffle, while on one hand Townsend is exhibiting his blackness by pointing out the obvious bias behavior of the white studios but also exhibiting the talent and recognition seeking of the black actor. Townsend’s almost biographical parody of movies, television shows not only his range as an actor but also h is since of humor of the angst of being an actor chosen solely for the color of your skin. Robert Townsend through situational and dramatic irony and by exhibiting how the white ideals shape the identity and description of what is black and how Hollywood has warped it. Robert Townsend plays Bobby Taylor a struggling young man actor who is with a healthy imagination and a dream of becoming a serious actor. Bobby family reluctantly supports him in his endeavors but his mother, and grandmother played by Starletta DuPois and Helen Martin secretly pass judgment on his chosen career path while his co-worker Donald and Tiny at the Winky-Dinky Dog played by co writer Keenan Ivory Wayans and Lou B. Washington openly mocks his dream. Crushed are Bobby dreams of playi... ...ood Shuffle" And "I'm Gonna Git You Sucka." Cinema Journal 38.3 (1999): 50-66. JSTOR Arts & Sciences III. Web. 3 Dec. 2011. Fanon, Frantz. Black Skin, White Mask. New York: Grove, 1967. Print. Grant, William R. Post-soul Black Cinema: Discontinuities, Innovations, and Breakpoints, 1970-1995. New York: Routledge, 2004. Print. Harrison, C. "W.J.T. Mitchell, What Do Pictures Want? Chicago: University of Chicago Press, 2005. 380 Pp., 16 Col. Plates, 84 Halftones, 10 Line Drawings. Hardback $35, 24.50 ISBN 0-226-53245-3." Journal of Visual Culture 6.1 (2007): 160-63. Print. "The Souls of Black Folk Study Guide - W. E. B. Du Bois - ENotes.com." ENotes - Literature Study Guides, Lesson Plans, and More. Web. 03 Dec. 2011. . Tourà ©. Who's Afraid of Post-blackness?: What It Means to Be Black Now. New York: Free, 2011. Print.

The Restoration of Old Buildings in Major Cities

The Restoration of Old Buildings in Major Cities in the World Spends Numerous Government Expenditures. This Money Should Be Used in New Housing and Road Development. To What Extent Do You Agree or Disagree? BY sunshine's The restoration of old buildings in major cities in the world spends numerous government expenditures. This money should be used in new housing and road development. To what extent do you agree or disagree?There currently exists a hot debate over whether a large proportion of government expenses should be allocated to restore historical architecture or be invested in constructing new houses and roads. From my personal point of view, spending on new housing and road improvement has a far greater value between the two and its budget allocation is necessary. A primary reason that sufficient funding should be provided towards building houses and roads is that the employment provided by such public works may relieve the financial burden of working families.For one thing, new housing and road projects may initially require tremendous amounts of labor and materials, thus creating various Job opportunities for engineers, truck drivers and electricians, among others. Once the projects are completed, ongoing maintenance work would need to be overfed in the new areas. Filling these vacancies would generate income for workers and thus ease the burden of living for many households. Moreover, reallocating the budget to make progress on new homes and better roads may enhance productivity in the economy.Advanced basic infrastructure, road systems in particular, would establish an effective transport network. If the government were to withdraw funds from restorations and designate a higher percentage of expenditure to achieve well-maintained roads, traffic Jams could be reduced or even been eliminated to some extent. As a result, residents, consciousness and officials may waste less time on the road, which allows extra hours for other economic activities.There is no doubt that restoring traditional buildings to their original form can stimulate the economy through the tourist industry. Examples of cultural heritage that are well preserved may attract visitors from other parts of the world and lead to profits in travel agencies, souvenir stores and hospitality companies. However, the have greater market efficiency and wider economic benefits, particularly for workers and their families. Therefore, I am in favor of funding new housing and road development.

Cellphones and Digital Networks

Cell phones have been around for nearly 15 years and are now everywhere you look. Over a quarter of Americans and a half of Europeans own cell phones and the numbers have been increasing exponentially. With the continuing increase in technology cell phones have become smaller, cheaper, and thanks to the move from analog to digital the calls are much clearer. They offer a great amount of convenience, and can be very economically for the busy businessman on the go. Advancements in cell phones are always being made, giving a clearer sound and lighter feel, as well as a longer life. The cell phone industry has been one of the fastest growing in the world. The electronics are fairly simple, but they are so small that they are truly and engineering marvel. This paper will discuss in depth the many different components of the average cell phone, and talk about how it converts your voice into something that can be sent through a digital network. The paper will also look at how the inner workings allow for a phone to act as a microcomputer, with Internet access, address books, and even games. Finally, it will review the many exciting ideas for this growing market and look to the future of the industry, and how the industry plans on overcoming various limiting factors. Alexander Graham Bell invented the telephone in 1876, 18 years later Guglielmo Marconi created the first radio. It was only natural that these two great technologies would eventually be combined to create the cellular craze. In the 80's few people used radiophones, these phones were the precursor to cellular, but they had several limiting factors preventing them from every becoming a major part of everyday society. In the radio telephone system, there was one central antenna tower per major city, and no more than 25 channels available on that tower. Each phone needed a powerful transmitter, big enough to transmit 40 or 50 miles. It also meant that not many people could use radiotelephones due to the lack of channels. With the current cellular system any none adjacent cell can use the same frequency, so the amount of phones that can be used are nearly limitless. These cells also mean that each phone does not need a strong transmitter, so the phone can be a lot smaller. With the innovation of digital phones, many great features are now available, such as caller id, Internet access, and several other new features. It also meant that the phone would need a microprocessor to convert from analog to digital, this complicated the circuitry, but left it with new technology available the industry was able to make the phone as small as possible. The only restriction in size became the user-input devices, and the screen size. Usefulness of the Digital Cell Phone The digital cellular phone offers many advantages to today†s society. The conveniences that it offers over simply not having one are obvious and they vary from person to person. But there are many advantages over other types of phones as well. The cellular phone not only allows people to communicate with others while they are on the go, but it also offers many other features to help people. With the services that digital provides, people can access email and find information almost anywhere in the world for a reasonable fee. In the future, as the integration of phones and computers grow, people will be able to access tutorials in the field, and use them to communicate with specialists saving a great amount of time for many researchers. Today digital cell phones, such as the one shown in Appendix C figure 1, can process millions of calculations per second in order to compress and decompress the voice stream. In order to do this each phone is equipped with a circuit board that contains many different chips. The circuit board of a common phone is shown in Appendix C figure 2. Two chips described earlier are the Analog-to-Digital and Digital-to-Analog conversion chips that translate the outgoing audio signal from analog to digital and the incoming signal from digital back to analog. There is also a Digital Signal Processor that is highly customized processor designed to perform signal manipulation calculations at high speed. The microprocessor controls the keyboard and display and deals with command and control signaling with the base station, it also coordinates the rest of the functions on the board. This microprocessor is as powerful as the super computer of the 70's that took up whole rooms, but is now the size of a finger. By using its arithmetic/logic unit or ALU it can perform all mathematical operation that run many of today features in phones. It is also responsible for the transfer of data throughout the phone. It will also make decisions and then run a new set of instructions. In Appendix C figure 3 a very simple microprocessor is shown. Cell phones use microprocessors that are much more complex, but the use the same idea. The ROM and flash memory chips provide storage for the phone's operating system and customizable features, such as the directory and various simple games. (Appendix C figure 4) The RF and power section handles power management and recharging, and also deals with the hundreds of FM channels. Finally, the Radio Frequency amplifiers handle signals in and out of the antenna. The Radio Frequency amplifier is the same device as you would find in your car's radio. The display has grown considerably in size as the number of features offered by cell phones has increased. Most phones currently available offer built-in phone directories, calculators and even games. It some new products that will be discussed later, cell phone counter as PDA's offering very large screen and offer all of the benefit you would find in today's hand held computers. The display is a liquid crystal display (LCD). It is made of thousands of tiny crystals with two possible colors. They have recently announced that they will be offering color screens on some new phones that work like the display of a laptop computer. Very small speakers and microphones, about the size of a dime, amplify the analog waves. These devices are just like that of a portable radio and the microphones used on television talk shows. They are both wired to the microprocessor. In order for digital cell phones to take advantage of the added capacity and clearer quality, they must convert your voice into binary information. This means that it must break it down to 1's and 0's. The reason that this is so advantageous is that unlike analog, digital is either on or off, 1 or 0, instead of oscillating between the two. For the conversion, the device must first record an analog wave, such as the one in Appendix B figure 1. To create the highest fidelity possible, it records number to represent the wave, instead of the wave itself as represented in Appendix B figure 2. The cell phones analog-to-digital converter, a device that is also found in a CD player, does this process. On the other end a separate digital-to-analog converter is used for playback. The quality of transfer depends on the sampling rate, that controls how many samples are taken per second, and the sampling precision. The precision controls how many different levels are possible in the sample. The better these two are the clearer the sound, but it takes a higher speed processor and requires a greater amount of data transfer. In Appendix B the benefits are shown in figure 3. Most common digital cellular systems use Frequency Shift Keying to send data back and forth. This system uses one frequency for 1's and another for 0's and rapidly switching between the two. This requires optimal modulation and encoding schemes for recording, compressing, sending, and then decoding without loss of quality. Because of this digital phones contain an amazing amount of processing power. The cellular network is web of towers covering areas, generally thought of as hexagonal cells as shown in APPENDIX A Figure 1. The genius of the cellular system is because cell phones and base stations use low-power transmitters, so the same frequencies can be reused in non-adjacent cells. Each cell is about 10 square miles and has a base station that consists of a tower and a small building containing the radio equipment. As more people join the cellular world, companies are quickly adding more towers to accommodate them. Every digital carrier is assigned different frequencies, an average carrier may get about 2400 frequencies per city, and this number is about three times the amount as analog. The reason that more channels are available is because digital data can be compressed and manipulated much easier than analog. Each tower uses one seventh of the available frequencies, so none of the surrounding 6 towers interfere. The cell phone uses two frequencies per call, called a duplex channel. The duplex channel allows one channel to be used for listening and the other for talking, so unlike a CB or walkie-talkie, both people can talk at the same time. This system currently allows for about 168 people to talk in each cell, for each system. The cellular approach requires a large number of base stations in a city of any size, but because so many people are using cell phones, costs remain low per user. Every cell phone has a special code associated with it, called an electronic serial number (ESN). It is a unique 32-bit number programmed into the phone when it is manufactured. When the phone is activated another five digit code called a system identification code (SID), a unique 5 digit number that is assigned to each carrier by the FCC, is imprinted in the phones memory. When you first power up a cell phone, it checks a control channel to find the SID. If the phone cannot find any control channels to listen to, it knows it is out of range, and displays a no service message. After finding the SID, the phones check to see if it matches the SID programmed in the phone, and if it does not match it knows that the phone is roaming. The central location that the cell phone is registered to keeps track of the cell that your phone is in, so that it can find you when someone calls the phone. When the phone is turned on it sends its ESN to the control channel. If the phone goes out of range, it will take a short while to locate your phone when it enters back into service. This can cause loss of calls, even though the phone is in service, but this problem is very temporary. When someone does call your phone it is sent to the central tower called the Mobile Telephone Switching Office (MTSO). This office is continually communicating with the cell phone. It sends and receives the calls, as well as telling it what frequencies to use. This is all done through the control channel, so it does not impair any calls. As you move toward the edge of your cell, the cell's tower will see that your signal strength is diminishing. At the same time, the base station in the cell you are moving toward, which is listening and measuring signal strength on all frequencies, will be able to see your phone's signal strength increasing. The two base stations coordinate themselves through the MTSO, and at some point, your phone gets a signal on a control channel telling it to change frequencies. There are three common technologies used by cell phone providers. These are Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA). In FDMA every call is done on a separate frequency. FDMA separates the spectrum into distinct voice channels by splitting it into uniform chunks of bandwidth. This is very similar to the way that radio stations operate. Each station is assigned a signal at a different frequency within the available band. FDMA is used mainly for analog transmission, so it is slowly being phased out. It is capable of carrying digital information, but it is not considered an efficient method for digital transmission. Time Division Multiple Access gives each call a certain amount of time on a frequency. The Electronics Industry Alliance and the Telecommunications Industry Association use TDMA. In TDMA, a narrow bandwidth that is 30 kHz wide and 6. 7 milliseconds long is split time-wise into three time slots. (Appendix D, figure 1) Each conversation gets the radio frequency for one-third of the time. This is possible because voice data that has been converted to digital information is compressed so that it takes up significantly less transmission space. Therefore, TDMA has three times the capacity of an analog system using the same number of channels. TDMA systems operate in either the 800 MHz or 1900 MHz frequency bands. Some phones have the ability to switch between bands. This function is called simply Dual-Band, and is important when traveling between different band frequencies. TDMA is also the access technology for Global System for Mobile communications. The Global system uses different frequencies in different areas of the world and is not compatible with other TDMA systems. GSM operates in the 900 MHz and 1800 MHz bands in Europe and Asia and in the 1900 MHz band in the United States. GSM systems use encryption to make phone calls more secure. GSM is the international standard in Europe, Australia and much of Asia and Africa. In covered areas, cell-phone-users can buy one phone that will work anywhere else the standard is supported. To connect to the specific service providers in these different countries, GSM-users simply switch SIM cards. SIM cards are small removable disks that slip in and out of GSM cell phones. They store all the connection data and identification numbers you need to access a particular wireless service provider. Unfortunately, the 1900 MHz GSM phones used in the United States are not compatible with the international system.