Identification of Major Issues of the Beijing EAP Free Essay Example, 1000 words

In general, Mr. Yang presumably felt he was in control of all the matters concerning the departmental management, leaving Ms. Song in confusion as to what her roles are, including the assignment of duties to Mr. Yang. This prompted Ms. Song to request the CEO to assign training tasks directly to Mr. Yang. The organizational theory of organization behavior explains the need to have a matrix organizational structures that blend the functional and project authorities in an organization. Mr. Yang s training department represents a functional structure in the organization. Meanwhile, Ms. Song being in charge of projects holds a projective office structure. This formation enables the authority of a functional manager to flow downwards to members of his/her department, while the project manager issues authorities to functional managers. This outlines the pattern of hierarchy in the project. A project manager is in charge of conveying messages within an organization concerning the project. In large corporations such as BEC, the project manager should hold the authority of giving orders as per the directions of the project. The flow of information should come from the top management down to the departmental managers through the project managers. We will write a custom essay sample on Identification of Major Issues of the Beijing EAP or any topic specifically for you Only $17.96 $11.86/pageorder now Therefore, Ms. Song should have taken control of communication, giving the necessary guidance to the functional managers. Motivation and leadership is a key function of a project manager in the matrix organizational structure. The project managers should be the person overseeing the limited time of the completion of a project. Normally, functional managers do not notice the ineffectiveness of their departments, and often need a neutral observer to judge the performance of their departments. In the project, therefore, a project manager eliminates the bureaucracy that exists in departments, thereby motivating and challenging the employees towards completing the project upon the set deadline.

Animal Experimentation Is Fundamental For Medical...

Animal experimentation has been a controversial issue amongst scientists and animal activists since the early 1600s (Animal Testing - ProCon.org). When it comes to the topic of animal experimentation, most of us will readily agree that it’s necessary for medical research. Where this agreement usually ends, however, is on the question of morality. Whereas some are convinced that it’s unethical and scientifically unnecessary, others maintain that it’s needed for medical progress. My stance on the subject is animal experimentation is fundamental for medical advancement and cancer research. An ample amount of human deaths are being avoided every single day due to the studies found through animal experimentation. Animal research has led to the development of treatments for numerous diseases, cancers, and illnesses and have benefit a great amount of people (Americans for Medical Progress). I, myself, have befitted from animal experimentation. I have a skin disease known as psoriasis. It’s non-contagious, but incurable. However, animal testing has led to the development of creams, shampoos, and treatments that have helped my condition. Without animal experimentation, these treatments couldn’t have been created, and my condition would be abominable. Not only do humans benefit from animal experimentation, but animals benefit from it as well. Animals are exposed to just as many, if not more, disease as humans are. Without animal experimentation, veterinarians and other health careShow MoreRelatedHow Do The Contributions Of Animal Testing To Global Medical1309 Wo rds   |  6 Pagescontributions of animal testing to global medical science justify whether or not it should be banned? According to the Humane Society International (HSI), animal testing or animal experimentation for medical research refers to the experimentation on live animals for the purposes of investigation on diseases, medical treatments, or fundamental biology. Charles Gross, a former member of the History of Neuroscience committee of the global Society for Neuroscience, states that animals were used for improvingRead MoreEssay about The Good, the Bad and Ugly of Animal Experimentation1197 Words   |  5 PagesThe Good, the Bad, and the Ugly of Animal Experimentation Animal experimentation plays an important role in today’s medical and pharmaceutical advances, but many question the morality of such a use of animal life. Whether one argues that testing different products and drugs on animals is necessary or not, this has become an integral part of developing products. From that Tylenol we pop to get rid of our headache to that perfect shade of pink lip gloss, animal testing is used in order to produceRead MoreEssay about We Need More Animal Research, Testing, and Experimentation1416 Words   |  6 PagesWe Need More Animal Research, Testing, and Experimentation    A life can be taken or created in a matter of seconds and with that has come the miracles of modern medicine. People have come to expect science to save lives, prevent illness, relieve suffering and improve the quality of life. The means of curing, treating and preventing diseases are not achieved by magic or accident. Medical advances are gained through years of intensive research -- research in which laboratory animals have playedRead MoreEssay on Animal Experimentation and Research2491 Words   |  10 PagesAnimal Experimentation and Research In the basement of the psychology department here, a poster hangs on the wall; on it is a picture of two white lab rats and a caption that reads, ?They?ve saved more lives than 911.? This poster hangs on the wall of the room where I performed brain surgery on a rat. Many people would be morally opposed to this and any other form of animal research and experimentation and feel that it should be banned. This heated debate has been going on for centuries withRead MoreThe Importance Of Animals For Animal Testing1754 Words   |  8 PagesAnimal research, also known as in vivo testing, is the use of animals for experiments. Experimentation on animals dates back to as early as 500 BC, making this form of medical education and research one of the most fundamental known to humans. Almost 400 years ago, a doctor named William Harvey used animals to discover how blood circulated in the body. This discovery is considered the spark of the scientific revolution in which many lives were saved a ll thanks to the help of animal testing. The modernRead MoreStem Cell Research Vs. Cloning1366 Words   |  6 PagesIntroduction: Stem Cell Research vs. Cloning Stem cell research entails the development and use of human embryos and stem cells. After the embryonic stem cells are taken from aborted fetuses or fertilized eggs, scientists study the cells. Dating back 30 years, scientists began their first attempts of deriving embryonic stem cells from the embryos of a mouse. After examining details of the biology behind mouse stem cells, scientists moved onto the biology of human embryos. Through in-vitro fertilizationRead MoreA Research Study On Stem Cell Research2115 Words   |  9 PagesStem cell research, through its ethics, methods, and funding, has caused great controversy over the past several decades. Scientists, medical specialists, religious groups, spiritual groups, the government and the public have devoted a major interest in this subject. Some portray stem cell research as a dangerous, inhumane study whereas others see it as a growing beneficial factor for opportunity of the advancement of the medical world. Stem cell research has been proven to aid various diseasesRead MoreAnimal Testing Should Not Be Banned Essay2144 Words   |  9 PagesAnimal testing has been around for centuries. It started out for curiosity reasons; people wanted to learn more about the internal construction of the body and animals were convenient—more so than humans. When it comes down to it, the word animal testing and animal research are interchangeable, moreover, both relate to the same meaning: the use of animals in scientific experiments. One of the scientists that made the first major use with animal testing was Louis Pasteur in the finding of milk pasteurizationRead More The Science and the Laws Impacting Human Cloning Essay5866 Words   |  24 Pagesnuclear somatic transfer1. It is nuclear somatic transfer that is the concern of this paper and relevant to the subject of human cloning. Any competent discussion of the science that may make human cloning possible begins with the cell, the most fundamental component of all organisms. Normally, a single fertilized egg containing all the information needed to create an organism will give rise to every other cell in the organism. In complex organisms, cells undergo a process of differentiation whereRead MoreGenetics: Past, Present and Future Essay example2599 Words   |  11 Pagesthe time the 21st century commenced, science found that the answers to these questions can be found in each cell of the body. Genes. But what are genes truly? Who were the scientists who contributed towards their discovery? What are the recent advancements in the field of genetics, and what does the future hold for this field? 1. The Past To understand the functioning of genes and even the structure of genes, it is essential to know the history of genes, and past assumptions of hereditary

Book talk Free Essays

Artemisia fowl Is the heir to a multi-notational criminal empire. He Is witty, cunning and lust when you think your one step ahead of him you are ten steps behind. He has outsmarted many of the world’s criminal elite In Just fourteen years and If given the opportunity he will do the same to you no matter who you are. We will write a custom essay sample on Book talk or any similar topic only for you Order Now The book Is about manufacturer stole from arteries. ]on would have already broken Into the computer If Artemisia hadn’t built an eternity code into it. This eternity code is by name supposed o take eternity to break. The setting for most of the book is in the Spiro tower in New York, but there are many other places the book takes place too. The author doesn’t really specify when the book takes place exactly but after reading it I would say that it takes place in modern day united states, sometime around 2009 up to now. The main character is Artemisia fowl; he is extremely outgoing and VERY witty. He reminds me very much of Courtney budged because in the book he shows many of the qualities that Courtney does in day to day life like being smart with people in general and Ewing two steps ahead of everyone. The main conflict is that Artemisia is having problems getting back the computer because the Spiro tower is heavily guarded and very secure and also the fact that he is locked in a vault like prison cell 80 floors down from where the computer is being held. The authors writing style is very easy to follow, he writes in a slow paced way that is never hard to understand so if you get confused with other books I would recommend this series to you’d would say I like this book mainly because of the authors writing style and also its very easy to get into swell,its very similar to the writing style of Suzanne Collins . Would say that the theme is that friendship trumps wealth because Artemisia almost looses every friend he has trying to get the computer back. ‘ think the book was absolutely hands down the best book have ever read for many reasons but mainly because of the moment when he burns the waitress at a restraint really bad. He went there to meet with Jon Spiro to discu ss the new computer but when he got there Jon hadn’t arrived yet and so the waitress came out to take his order,keep In mind that artless Is only 14, so she lad†oh hello there little boy, would you Like to see the children’s menu? And artless said â€Å"no mademoiselle would not Like to see the â€Å"children’s† menu as I have no doubt the the â€Å"children’s† menu Itself tastes better than the food on It† â€Å"what I would Like If a saute ©deed swordfish over a rosemary rue with a mushroom risotto on the side. And Irish spring water please if you have It,no Ice either as I have no doubt that you Ice Is made from tap water and that would rather defeat the purpose of spring water. † And remember laughing in my head. How to cite Book talk, Papers

Trip of a Lifetime free essay sample

The gas gauge was dropping, getting perilously close to â€Å"E,† but my aunt paid it no notice. We continued at 70 miles per hour down the Kentucky highway, singing along to the radio. Suddenly, the Jeep lurched backwards, bounced, slowed down, and continued forward. My aunt looked at me and pressed harder on the gas pedal. The Jeep slowed down. â€Å"I told you we should have gotten gas,† I said, my voice just out of audible range. We pulled over to the side of the highway, and I was sent to the back of the car to keep my fourteen-year-old brother and four-year-old cousin calm. In the front seat I could hear my aunt on her cell phone, presumably with AAA, hysterically recanting what had just happened. She turned back to me and said, â€Å"Do you know where we are?† I solemnly shook my head. â€Å"They can’t find us,† she said. We will write a custom essay sample on Trip of a Lifetime or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page â€Å"We could be here for awhile.† I was crushed. But being the oldest grandchild on both sides of the family, brave faces are my specialty. I smiled and sang along to Lion King with my little cousin and helped my brother explain the situation to our mom on the phone. After sitting it out in the car, we all reached an internal body temperature of about 105. Everyone was hostile and frustrated. Luckily, a kindhearted stranger, who happened to be driving a tow truck, stopped to assist us. After uncomfortably squeezing three adult bodies, one child in a car seat, and two Labrador Retrievers into the tow truck, we were off. The stranger drove for roughly a half hour off the highway, after which we finally reached â€Å"Al’s Garage† in Somerset, Kentucky. We were then informed that the damage to the Jeep was irreparable. It turned out that we hadn’t run out of gas, but had busted the engine. Unless we wanted to spend a week in Somerset, we needed a rental car to get us home. So my aunt hitched a ride with Al’s son to the local Hertz. Meanwhile, it was my job to look after my brother, cousin, and the two dogs. At the sight of my aunt’s disappearing back, my little cousin’s lip began to quiver. It was a look I knew too well. Thinking quickly, I whipped my iPod out of my purse and scanned the list of Disney songs. Once the Lion King was back on and the headphones were in my cousin’s tiny ears, everything was alright. Twenty minutes (or five Disney songs) later, my aunt returned with a Ford Focus. We contorted ourselves and our luggage into the tiny car, and were headed home once again. Looking back on this experience, I can’t help but laugh. It’s the kind of thing that seen in movies, and it happened to me. I learned the importance of staying calm, and also that I am a role model for my younger family members.

Apocalypses And Mark Gospel Essays - Prophets Of Islam,

Apocalypses And Mark Gospel Mark is most likely the first of the Gospels to be written because it is the shortest and tells of the ministry of Jesus. Mark stresses Jesus' message about the kingdom of God and how it is breaking into human life as good news and that Jesus himself is portrayed as the "gospel of God." Jesus is explained as the Son of God who is sent down to rescue everyone. His life is predestined as a sacrifice for humanity. The beginning of the book sets the tone of Mark by the actions of John the Baptist and God as he speaks during Jesus' baptism declaring Jesus his son. Also in the beginning Jesus is supposed to baptize the Holy Spirit and that the temptation of Satan fails. Examining the verse 14-15 of chapter 1 one can understand Jesus proclamation as Gospel: "fulfillment, the nearness of the kingdom and therefore the need for faith." From this point on we see miracles being performed on the people. It almost seems as though he is carrying out these miracles in order to make people either fear him, or prove to people who he is. People then start to take a real liking to him as he helps them unconditionally with all of their ailments. Jesus later appoints 12 disciples to carry out his reign and to drive out the demons as he is doing. Though we see in chapter three the introduction of the Apocalyptic thought. Jesus is accused of being "Beelzebul" which is a word used for Satan, they say this because they do not have an explanation for him driving out the demons. We also see in this chapter that Jesus say's that his family is those that believe in God and follow his reign. This insinuates the idea that Jesus is in all of us. Continuing the story we see Jesus is preparing for everything that is to happen. He is aware of the disciples that are going to betray him, and that he is going to be sentenced to death by Pilate. Then the Last Supper where he is to foretells the future. In chapter 13 we are told about the destruction of the Temple. This is very apocalyptic in tone because it tells of the falling of all the great buildings right down to the last stone. He says that there will be many wars, and many nations will fight but it will all be built again, saying that intervention will only happen after destruction. What he is talking about is the Romans coming to take over Jerusalem and to destroy the temple. Though Jesus does not say when this is going to happen. The book of Mark ends with Jesus being crucified and dying on the cross for everyone. He was buried and then the following day as Mary Magdedalene, Mary Mother of James and Salomon went to go anoint his body they found that his body was not there. They assumed that Jesus had risen. He appeared to the eleven and said go out and proclaim what has happened and those that believe will be saved and those that don't will be condemned. This is the final portion of Mark and it's proclaims that those who do not believe will be punished. This is a very similar attitude that was seen in Daniel as God the punisher.

Social Boundaries essays

Social Boundaries essays High school is undoubtedly one of the most socially segregated places anywhere. No matter how welcoming and open a high school may seem, it is almost a guarantee that there will be social groupings that students will fall into. From my experience at Marshall County High School I have seen the various social boundaries and have seen their benefits and downfalls. Overall, I think that the social groupings are beneficial, although they can cause many undesirable problems. MCHS has a diverse student body. On any given day, you can walk into the cafeteria at lunchtime and see several different social groups. Some of these social groupings are more obvious than others and may even be considered stereotypical. One of the largest and most commonly seen groupings is the preps, who usually dress nicely, are generally concerned with their appearance, and may be athletic enthusiasts. Another social grouping I have seen at the high school is referred to as the rednecks. This group includes students who are less concerned with personal appearance and may enjoy activities such as hunting. There are also many smaller social groups and cliques among the student body. It is only natural for people to flock toward other people who share the same interests or characteristics. If there were no differences in social preferences, the world would seem like a pretty boring place. From what I have seen, I feel that most other students enjoy our social groupings. This allows students to associate with other students that they are likely to connect with and stay away from students they might not be compatible with. Personally, I like the social system at the high school sometimes, because I have met many friends who have happened to be associating themselves with the same group with which I was associating myself. However, I do feel that this system of social boundaries and groupings has its drawbacks. ...

Elections Essay Example | Topics and Well Written Essays - 1250 words - 1

Elections - Essay Example e map conducted by the Fix ( Chris , and Aaron Blake ) Obama starts the general election with 15 states (plus the District of Columbia) and 196 electoral votes strengthen him while Romney begins with 21 states and 170 electoral votes firmly in his corner. (One of the states sturdily for Romney is Indiana, where Obama won in 2008 but no one expects a repeat performance in 2012). Another three states — Pennsylvania (20 electoral votes), Michigan (16) and New Mexico (5) — incline toward Obama while Arizona (11) and Missouri (10) lean toward Romney. Adding them up lends Obama 237 electoral votes and Romney 191 electoral votes. (Chris, and Aaron Blake) While Obama was a much likely candidate than Romney, victory will be decided by the nine swing states — Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio, Wisconsin and Virginia — which are the real toss ups and comprise 110 decisive electoral votes and Obama won because he gained majority of the seats of these swing states, the victory was a clear, clean sweep by Obama in these swing states (Chris, and Aaron Blake). Other factors that were critical to the results of the Presidential race were the Swing states, ethnicity, Race, affect of the debates made by candidates’ income and unemployment and solid, fix strongholds also had a profound impact on the outcome, Obama proved to be a strong figure head, he inherited two wars, but the way he handled war on terrorism is praiseworthy. Currently the way he handled the storm was also a strong plus point for him, and increased his favorability ratio. (Andrews et al ) 5) If I could vote, I would have voted for Mitt Romney, for that would be what I call â€Å"Real Change† as that was the slogan the two candidates were vying for. Things in Obama’s last tenure were not all that satisfying and room was still there for improvement. Romney’s debates were oozing with confidence and his promises were more believable and real. His

Economics Essay Example | Topics and Well Written Essays - 2500 words

Economics - Essay Example A monopolist does not have to worry about any such retaliation due to imperfect competition. There are too many barriers of entry into a monopolistic market for new firms. The biggest barrier is that of economy. A monopolist is able to produce his product at a very low cost and it is not possible for the other producers to produce at such a low cost. The competitors are not able to invest in capital like the monopolist invests. The technology that is available to the monopolist is also not available to the competitors. Therefore, the monopolist lowers the price of his product at such a level at which other producers cannot survive. This way, the competitors are driven out of the competition. When this happens, the monopolist raises the price of his product at his desired level again. Another aspect of monopoly is the network effect. The product of the monopolist has no close substitutes. The new consumers also tend to use the monopolist’s product because it becomes a social no rm and a fashion. This is why the demand for his product is always likely to increase. This aspect also serves as a barrier of entry for new firms and as another incentive for monopolist to raise price. Patents and copyrights provide legal protection to a monopolist from competitors. Generally, a monopolist earns supernormal profit which means that the marginal revenue is lower than the price. The demand curve for the monopolist’s product is relatively inelastic. This means that any change in price does not affect the demand for the product. Monopoly is one of the rare scenarios in which the demand for the product is relatively inelastic. Normally, the price goes up in this case because it is very easy for the monopolist. In a competitive market, it is very hard to raise the price of the product because the competitors do not follow the new price. The demand for the product in perfect competition is perfectly elastic and there is no demand if a single firm raises its price. T here is no such case in monopoly. A monopolist has a great influence on the consumers. There are times when a monopolist has to face some retaliation from the consumers when he raises the price unreasonably. In order to deal with this situation, he uses his control on supply. He cuts the level of supply at his own will and it becomes hard for the consumers to get their hands on the monopolist’s product. When they do find the product, they are willing to pay the price asked by the monopolist. This way, the monopolist curbs the reaction of the public and earns real economic profit during the process. However, he does lose some of his customers in the process because the demand for his product is not perfectly elastic and some of the customers are no longer able to afford the product. His ability to control supply and affect the consumers is another barrier for his competitors. Another tactic for a monopolist to make high profit is price discrimination. He segregates the market into two parts. The consumers who need his product more or have an ability to pay more are charged high prices. The rest of the consumers are charged lower prices. Price discrimination works successfully and is profitable when the elasticity of demand of one market is different from that of the separated market. This way, the monopolist earns more profit from the market whose elasticity of de

The multicultural Effect Essay Example | Topics and Well Written Essays - 1500 words

The multicultural Effect - Essay Example (Silko 1996, 43) These words f Leslie Marmon Silko describe aptly what this ReVision issue is about: storytelling. Indigenous conversations. Recovering indigenous conversations. Remembering stories. Putting them back together. Cherishing the fragments we find. Exchanging stories. Finding ways to bring the immediacy and presence f the stories told in front f a group f people onto paper and between journal covers. Sharing stories between groups f people, Sami siidat, German Sippen--communities (some f these groupings are now called cultures, or societies, or nations, or tribes). The primary focus f the contributions is not agreement or disagreement with Eurocentered views on narrative knowing. Instead the articles, taken together, walk their own path, affirming an ancient way f being present to knowing. That is all. This issue is an invitation to remember that practice and to participate in it--today--with all that that might mean in our contemporary situation. Within the Eurocentered context, the concern would be with the defense, explication, placement, or support f narrative knowing within the edifice that Eurocentered thinking tries to maintain, even as it crumbles and disintegrates at the external and internal margins. Much f what has been written about narrative knowing presents such amendments, usually framed as advances. Progress f thinking. A contribution on the evolutionary trajectory. This is the stage set by Eurocentered thinking for the justification and defense f narrative knowing. That stage matters not in an indigenous or a remembered indigenous context. The stakes are much higher. There are many more criteria. They are in the landscape. In the ancestry. In history. In what is commonly called myth. In gossip. In the narrative plot provided by the stars. In the remembrance f the pain f what people have done to each other and are doing to each other. Individuals all. In the rejoicing about the beautiful things people have done. Because these kinds f criteria elude Eurocentered thinking to a large extent, they cannot--and should not--be justified in that context. Pressures for such justification arise from the need to the maintain the social construction f whiteness. Though it may seem extraordinary to the Eurocentered mind, in the indigenous context, one fact stands out as a simple truth that native people live by: "Whether we know the stories or not, the stories know about us" (Silko 1996, 150). We may not remember our ancestry or honor it, but the ancestors remember us. There is hope in this. Storytelling is allowing completeness in a nutshell: hologrammatically. Here we don't find philosophy apart from the cycles f the seasons--yet we find science. Here we don't find agriculture separate from the local narratives--yet we find astronomy and agroastronomy. Here we don't find navigation apart from star and weather lore--yet we find nautical science. In the narrative universe f these worlds, story is not an individualistic or existential project. It is the survival f the self woven inside, outside, and in between through precise presence. There is no possibility f standing apart or objectifying or dissociating. What an advance to remember such pr actices. The current issue started out with a different design in mind: I was in the process f inviting several authors and informing them to assume the importance and validity f narrative knowi

The Significance Of Larmor Frequency In Mri English Language Essay

The Significance Of Larmor Frequency In Mri English Language Essay When a magnetic field is applied to an atom, the nuclear spin will be orientated with the field. The spin allows absorption of a photon of frequency ÃŽÂ ½L, which is dependent on the magnetic field applied. ÃŽÂ ½L = ÃŽÂ ³ * B In the equation above, B is the magnetic field, ÃŽÂ ³ is the gyromagnetic ratio and ÃŽÂ ½L is the larmor frequency. When atoms are placed in a non-uniform magnetic field, the nuclei of the atom have varying larmor frequencies due to the equation. (b) Why does the RF field have to be applied exactly at the Larmor frequency to tip the net nuclear magnetisation? Some nuclei are said to be parallel to the magnetic field with some nuclei orientated anitparallel which are at a higher energy state. The energy difference between the two states is give by ΆE. When this energy difference is applied there is a transition from the lower energy level to the higher energy level. There is now more nuclei in an anitparallel orientation. When using the RF pulse it has to be resonance with the Larmor frequency. As the RF energy is applied the nuclei will orient themselves in the anitparallel position, this results in more nuclei being in a higher energy state. (c)Classically the spin population states are divided into parallel and anitparallel: what is the approximate population difference between these two states at 1.5T? In order to calculate the population difference use the larmor equation to find the frequency at 1.5 T f = ÃŽÂ ³B Where ÃŽÂ ³ = 42.6 MHz/T B= 1.5 T f = (42.6 x 10 ^6) Ά¡ (1.5) f= 63.9 x 10^6 secà ¢Ã‚ Ã‚ »Ã‚ ¹ Now use the following equation ΆE = hf to find the difference in population where h is plancks constant which is 4.14 x 10^- 15 eVΆ¡sec f is 63.9 x 10^6 secà ¢Ã‚ Ã‚ »Ã‚ ¹ ΆE = hf ΆE =4.14 x 10^-15 )(63.9 x 10^-6 secà ¢Ã‚ Ã‚ »Ã‚ ¹) ΆE = 2.65 x 10^-7 eV (d) Describe what is meant by the Free Induction Decay (FID) of the MR signal In the rotating frame, the net magnetisation vector decays as spins lose phase coherence and begin to cancel each other out. They do this because they experience slightly different magnetic field strengths due to interaction between spins (via their own oscillating magnetic fields). Slightly different magnetic fields means slightly different precession (Larmor) frequencies. This causes some spins to lag behind the average, and some get ahead of the average. Eventually the spins point in arbitrary directions and the Mxy component of the net magnetisation vector is lost. This decaying, oscillating signal is the free induction decay.  [1]   (e) Describe what is meant by spin-lattice relaxation. How is it described mathematically? One relaxation process involves a return of the protons to their original alignment with the static magnetic field. This process, called longitudinal or spin-lattice relaxation, is characterized by a time constant T1. The term spin-lattice refers to the interaction of the protons (spins) with their surroundings (the lattice or network of other spins). This interaction causes a net release of energy to the surroundings as the protons return to the lower energy state of alignment.  [2]   The spin- lattice relaxation is given by M_z=M_0 [1-exp (-t/T_1)] where M_z and M_0 components of the magnetisation vector and t is the time. (f) Describe what is meant by spin-spin relaxation. How is it described mathematically? Before a radio wave is applied, the precessional orientation of the protons is Random. The application of a radio wave brings the protons into synchronous precession, or in phase. When the radio wave is switched off, the protons begin to interact with their neighbours and give up energy in random collisions. In so doing, they revert to a state of random phase. As the protons revert to random orientation, the bulk signal decreases because the magnetic moments tend to cancel each other. This process is called transverse or spin-spin relaxation and is characterized by a time constant T2.  [3]   The spin-spin relaxation is given by M_x, y=M_0 [exp (-t/T2)]. (g) Using the spin echo sequence, describe how the timing parameters can be adjusted to reflect T1, T2 and proton density in the image. Question 2 Figure 2.1 : Image given in assignment (i)What are the two user variable parameters marked as a and b? Explain briefly in general terms how a and b might be chosen to achieve different image contrast weightings. The user variable a is the echo time and b is the repetition time. When there is a short repetition time and short echo time the result will be a T1-weighted image. A long repetition time and short echo time will give a proton density image, and long repetition time and long echo time will give a T2-weighted image. (ii) Identify the gradients markedd. Explain what is illustrated by the dotted horizontal lines in this part of the diagram. What user variable parameter directly influences what is happening ind? Briefly relate this to total scan time. The gradients markedd represents the phase encoding gradient. The user variable parameter that directly influences the phase encoding gradient is the frequency encoding gradient. The total scan time for a standard spin echo or gradient echo sequence is number of repetitions x the scan time per repetition (means the product of repetition time (TR), number of phase encoding steps, and NSA).  [4]   (iii)Identify the gradient e. If all other variables are considered fixed what user variable parameter would change the strength of this applied gradient? The gradient is e is the slice selection gradient. The user variable parameter that would change the strength of this applied gradient is the slice thickness parameter. The slice thickness is governed by the following equation: thk = BWtrans / (à Ã¢â‚¬ °0 ·GS) Where thk is the slice thickness, BWtrans is the transmitted RF bandwidth (the range of frequencies it covers), 0 is the gyromagnetic ratio and GS is the magnitude of the slice selection magnetic field gradient. So, slice thickness is inversely proportional to GS; increasing GS will yield a thinner imaging slice.  [5]   (iv) What is the waveform show in g? Give a brief description of how the signal from g is captured by the MR computer system and subsequently processed to form an image. The waveform g represents the echo signal received. Question 3 (A) Describe briefly the physical basis of the following MRI artefacts: Truncation or Gibbs Gibbs or truncation artefacts arise from going from a bright are to a dark area resulting in bright or dark lines which are present at parallel and adjacent borders where there is a sudden change in intensity. This type of artefact is associated with the number of steps used in the fourier transform to reconstruct the image . To minimize the effect of Gibbs or truncation artefacts more encoding steps are performed in order to lessen the intensity and narrow the artefacts. Figure 3.1 : Diagram shows the Gibbs effect resulting from a Fourier transformation of a sharp change in image intensity Zipper There are various causes for zipper artefacts in images. Most of them are related to hardware or software problems beyond the radiologist immediate control. The zipper artefacts that can be controlled easily are those due to RF entering the scanning room when the door is open during acquisition of images. RF from some radio transmitters will cause zipper artefacts that are oriented perpendicular to the frequency axis of your image. Frequently there is more than one artefact line on an image from this cause. Other equipment and software problems can cause zippers in either axis.  [6]   Figure 3.2 : When this image was taken the scanner room door was left open during the acquisition causing the zipper artefacts shown. Chemical shift Chemical shift arises from a variation in the resonance frequency due to the nuclear spin of protons in different environments like fat or water. Due to the magnetic shielding of different protons , will result in different resonance frequency and hence lead to miss registration of protons in the same slice during the fourier transform. The chemical shift artefact will appear as bright or dark band at the edge of the anatomy. High field strength increases the miss registration of the protons. Figure 3.3 : In this image the chemical shift artefact is seen as a small bright line in front of the femoral bone. (b) In a magnetic field, fat precesses at a lower frequency that water giving rise to a Chemical shift. At 1.5T, the frequency difference is 210Hz. For an image matrix of 256 x 256 and a receive coil bandwidth of 16 kHz, calculate the size of the shift between water and fat in pixels. To find the chemical shift use the following equations d = (n nref) x 106 / nref But know that nref = gBo The equation now becomes d = (n nref) x 106 / gBo where nref is resonance frequency g is gymagnetic ratio where g is 42.58 MHz/T Bo is magnetic field strength where Bo is 1.5 T n is resonance frequency of second component d is chemical shift difference Can now put these values into the above equations. Given that the frequency difference is 220 Hz d = (n nref) x 106 / gBo d= (220) x 106 / (42.58 x 106) (1.5) d= 3.44 ppm Question 4 Using diagrams where appropriate, briefly describe k-space under the following headings What does k-space represent K space corresponds to a matrix of the MR data and represents the image before processing like fourier transforms are performed. Within k-space each line represents a measurement, with a separate line for varying phase gradients. A line of height 0 represents a line with no phase gradient. Figure 4.1: In this diagram, Kx represents frequency, Ky represents phase directions. Each measurement is positioned at a different Ky coordinate (height) How is k-space normally filled The polarity and amplitude of the frequency and phase encoding gradients directly affect how k-space is filled. The amplitude of the frequency encoding gradients establish how far the k-space goes to the left or right and therefore gives the field of view of the image in the frequency direction. Positive values go from left to right while negative values go from right to left. The amplitude of phase encoding gradient estimates how far up and down k-space is filled up and down in the phase direction and hence determines the field of view in this direction. Positive values fill the top half while the negative values fill the bottom half. What determines k-space co-ordinates The k-space location (kx and ky coordinates) of data is governed by the accumulated effect of gradient events and excitation pulses.  [7]   How does an absence of data in k-space affect the image If there is some date missing in k-space this will result in a loss of resolution of the image. Question 5 (a) Describe four important safety hazards in MRI. Static magnetic fields Depolarization can be caused by voltages induced in flowing blood and the movement of muscles in the heart which can be detected by an electrocardiogram. In order to minimize this effect the magnetic field strength kept withing the following limits. 2.5 T for body of patients; 0.2 T for arms and hands of staff and 0.02 T for whole body of staff. Switching of the gradient magnetic fields Involuntary muscular contraction, breathing difficulties and ventricular fibrillation arise from eddy currents induced in the body. MRI should not be performed on patients with implants, as it can cause harm to the patient. In the case of strong fields, taste sensations can be experienced by the patient while flashes of light can be present on the patients retina. Magnetic field build up is usually 1-5 Ts to avoid symptoms. Radiofrequency fields In strong static fields, at high frequencies, heating can occur. The temperature should not rise above 1 degree Celsius on the patients skin. In order to minimize the heating affects the specific absorption ratio should not surpass 0.4 W/Kg and pulsed RF field should not go beyond 70 W Mechanical attraction of ferromagnetic objects This changes with the square of the magnetic field and inverse of the distance. Metal objects are made into projectiles if they come into the fringe field. For this reason non-magnetic material should be used. (b) What is meant by SAR? Define the units used to measure this parameter. The Specific Absorption Rate is defined as the RF power absorbed per unit of mass of an object, and is measured in watts per kilogram (W/kg). The SAR describes the potential for heating of the patients tissue due to the application of the RF energy necessary to produce the MR signal. Inhomogeneity of the RF field leads to a local exposure where most of the absorbed energy is applied to one body region rather than the entire person, leading to the concept of a local SAR.  [8]   What is the whole body limit? 4 W/kg averaged over the whole body for any 15-minute period.  [9]   Which sequences are a particular concern and may give rise to radio-frequency effects? Radio frequency effects occur when a patient is exposed to static magnetic fields in MRI. The Radio frequency pulses mainly produce heat, which is absorbed by the body tissue. If the power of the RF radiation is very high, the patient may be heated too much. To avoid this heating, the limit of RF exposure in MRI is up to the maximum specific absorption rate (SAR) of 4 W/kg whole body weight (can be different from country to country). For MRI safety reasons, the MRI machine starts no sequence, if the SAR limit is exceeded.  [10]  

Theme of Witch Hunts in The Crucible and the Rwandan Genocide Essay

In 1953, a book/play called The Crucible was published. It was written by Arthur Miller as an allegory of the McCarthyism era. It talks of the causes and effects of the Salem witch trials in the late 1600's. The story is told in a way that made the people of the 50's realize how crazy they were actually acting. In 1994, two Rwandan tribes were fighting each other to the death. One was called the Tutsi tribe and the other was the Hutu tribe. These clans differed only slightly. The Tutsi were taller, had darker skin, and wider noses. The Hutu were shorter, had lighter skin, and thinner noses. This was the difference between them yet they fought for about 3 months until nearly half of the Tutsi were slaughtered. What a happy story. But anyways, what do these two things have to do with one another? They both dealed with witch hunts of sorts. The Crucible literally was about the witch hunts. In the Rwandan Genocide, Hutu were hunted down like the ?witches? were hunted during the Salem witch trials. Though both of these things talk about the same basic idea, there are many differences s... Theme of Witch Hunts in The Crucible and the Rwandan Genocide Essay In 1953, a book/play called The Crucible was published. It was written by Arthur Miller as an allegory of the McCarthyism era. It talks of the causes and effects of the Salem witch trials in the late 1600's. The story is told in a way that made the people of the 50's realize how crazy they were actually acting. In 1994, two Rwandan tribes were fighting each other to the death. One was called the Tutsi tribe and the other was the Hutu tribe. These clans differed only slightly. The Tutsi were taller, had darker skin, and wider noses. The Hutu were shorter, had lighter skin, and thinner noses. This was the difference between them yet they fought for about 3 months until nearly half of the Tutsi were slaughtered. What a happy story. But anyways, what do these two things have to do with one another? They both dealed with witch hunts of sorts. The Crucible literally was about the witch hunts. In the Rwandan Genocide, Hutu were hunted down like the ?witches? were hunted during the Salem witch trials. Though both of these things talk about the same basic idea, there are many differences s...