BLIP Echo Planar Imaging Method Essay Example | Topics and Well Written Essays - 2500 words

BLIP Echo Planar Imaging Method - Essay Example Sampling of k-space is different in EPI that enables high quality of images acquired. EPI uses quickly switching gradients to produce its echo train as against use of RF pulses in FSE. EPI frequency encoding gradient oscillates from positive to negative to create odd and even echoes. Each read gradient echo corresponds to one k-space with the positive and negative gradients changing the direction of the line that is read. The changing of direction of the line read results in a phase ‘blip’ causing a shift in Ky and this method of phase encoding is referred to as blip EPI. Characteristics of EPI: EPI has three distinct characteristics in terms of speed, the variety of contrast and the flexibility in terms of available resolution for imaging small structures like the pituitary gland. EPI offers higher speeds (6 to 10 times) of imaging of short temporal events under motion. It provides with high image quality by collecting more averages with increased slice frequency per TR . The signal to noise ratio of the images is high and the resolution is also high. Its usefulness depends on the MR system used and the efficiency is determined by the ability to perform 1282 or 2562 in a very short time to avoid large off resonance artifacts. It means that high quality images of moving patients can be obtained by using the speed of EPI. A variety of tissue contrasts (T1, T2 and T2*) are allowed by EPI for image acquisition and small structures are imaged using the flexibility in resolution where the field view can be reduced, the echo train length can be increased or geometric distortions can be reduced to increase the resolution. Also, just half of the data of the image can be gathered that can be further synthesized through conjugation to obtain the remaining data. Flexibility in contrast can be used to produce an image similar in standards to that of an SE image with the same TE and TR by using an excitation pulse in the front part followed by a 1800 pulse (T2* dephasing) to create the first echo. EPI compared to conventional fast imaging methods: EPI uses the Blip EP method of phase encoding where each phase blip between echoes causes a shift in k-space line. Each k-space line is contributed by the gradient refocused echo and is either read positively or negatively through the gradient change. The quickly switching gradients that produce the echo train are responsible for the odd and even echoes. When the lines are read, the reversed read lines are reordered before constructing the image. Also, the rf pulse is not used to create multiple echoes as in conventional FSE. Figure 1: (a) Pulse diagram of FSE, 4 echoes and (b) pulse diagram of EPI. Source: (McMahan, 2012). Benefits in EPI: Acquiring single snap shot images is much faster (20-100 ms) using EPI when compared to conventional FSE as gradient echoes take less time as all the encoding steps are obtained after one single excitation pulse is applied. This is in contrast to the train of rf pulses applied that increases TR. Also, EPI allows flexibility in contrast that enables even small structures to be imaged very fast. Further, slice coverage is increased with EPI when compared to FSE. EPI has fewer rf pulses that result in low specific absorption rate (SAR). As SAR is low, TR is also low, resulting in more slices to be covered in the same TR as in FSE. Sensitivity to resonance effects: A disadvantage in EPI is that it is sensitive to off resonance effects of the echo gradients

Future events Essay Example for Free

Future events Essay Richard here talks of a forthcoming golden era full of glory and hope. Whilst speaking in public, Richard uses this opportunity to defend him from being accused in future events. By praising the running of the country nobody would suspect him of becoming a family murderer. Again, in private Richard reveals his true feelings and again reveals to the audience future plots.  I am determined to prove a villain and hate the idle pleasures of these days. Plots I have laid, inductions dangerous. (Act 1 scene 1.Lines 30 +32) When speaking concealed away from the public, Richard provides insight into future events. Although it may appear that the war is over the royal family is about to confront another battle in the eyes of Richard. It is through what is said in private that Richard sheds light on future plots and events and to an extent he draws a relationship with the audience because of this.  The final area in which I will explore appearance and reality will be through the manipulation of religion. Richard of Gloucester is not the only character in the play to use appearance and reality as his two partners in crime prove. Catesby and Buckingham use religion as a weapon of disguising for Richards true personality and intentions. He is within, with two right reverend fathers, divinely bent to meditation .. To draw him from his holy exercise. (Act 3 scene 7.Line 60 + 61)  Buckingham endeavors to make Richard appear holy and innocent by portraying him as a devout, holy and religious man. By this point in the play we know that Richards life is not based on serving god but rather serving his own desires. His allies continue to do their utmost to mask his evil traits in front of the politicians.  This prince is not an Edward. He is not lulling on a lewd love-bed, but on his knees at meditation.(Act 3 scene 7.Line 70-71) Again, religion is manipulated to give a false identification of Richard. Their aim is to get Richard to become king and attain ruler ship thinking that they may get something in return. Buckinghams language reveals that he; Catesby and Richard are play acting.  Two props of virtue for a Christian prince .. and see a book of prayer in his hand. (Act 3 scene 7.Line 95+96)  Buckingham makes it apparent that this is a play within a play and uses the church and the word of god as a prop to make Richard look convincing on stage. Richard also does his part in covering up his true personality. I do beseech your grace to pardon me, who, earnest in the service of my god. (Line 104-105)  Richard once again stresses how devoted he is to god when really he is only devoted to getting himself raised to a godly figure in the form of king. Shakespeare reveals yet another plane to Richards ever- changing character through the manipulation of religion as we not only see a deceitful interpretator, a cold-blooded murderer but also a manipulative man. He has no regard for family, women or even god and this manifests the extent that he is willing to go to get what he wants. Shakespeare provides us with another peek into future events through the manipulation of Richard. Come, let us to our holy work again.(Act 3 scene 7.Line 245)  This holy work will in fact not be holy but will rather entail unholy and irreligious dealings. The work will contain further plotting and this braces the audience for further manipulation. This device measures the extent to which Richard will go to change his character. It also reveals that Richard isnt the only character that utilizes appearance and reality in the play and this reflects the amount of manipulation contained within the play. Appearance and reality is a device that Shakespeare cleverly uses to keep the character Richard of Gloucester running throughout the play. It revitalizes his character and interest in him is always stimulated because of this. To an extent, Richard uses appearance and reality as a stepping stool for further dealings in the future. Richard, the anti-hero, uses his physical appearance as a driving force for evil traits and deceive4s others into thinking that it makes him weaker. His contrasting treatment of women perfectly illustrates how well he can adjust roles when required. He is the master of deception as his opening soliloquy proves. It is what is said in private that reveals to the audience what Richards true intentions are and it is what is said in public that reflect lies. Shakespeare makes this link early on so that Richards changing wont fool the audience. Shakespeare mirrors appearance and reality through the manipulation of religion to show the extent that Richard will go to obtain what he requires. Appearance and reality is important because it shows that Richard is a character of dual interpretations and Shakespeare makes sure Richard uses it continually so that his character continues to fuel interest for the audience. Appearance and reality is a vital tool in the play as it not only plays a huge part in shaping events in the play but it also reveals future events that are to take place.

Plagiarism and the Internet :: Cheating Education Essays Papers

Plagiarism and the Internet A major concern among college students, high school students, professors and teachers is plagiarism. Most students are unaware of what exactly plagiarism is. They all have general ideas, but most donÏ€t know the extent to which it spans. On the other side, teachers and professors are unaware of how to handle the situation. All the technological advances and the World Wide Web make it easier for students to pass off anotherÏ€s work as their own. Plagiarism can be defined as using anotherÏ€s words or ideas as your own without stating the source of information. This not only includes words or ideas, but pictures, graphs, charts, and statistics. The only case where citing is unnecessary is when the fact is common knowledge that can be found in a variety of places and most people know about it. Students who plagiarize from the internet, donÏ€t even consider it really plagiarizing. They feel that since it is not a hard copy of the work that it really isnÏ€t wrong. This goes back to the idea that students today arenÏ€t even sure what to consider plagiarism. With the creation of the World Wide Web, students have the ability to access great amounts of information at a faster speed. Years ago, in order to plagiarize students had to spend hours searching through books to copy information from to write a paper. The internet today contains information on so many topics, that is almost impossible to not find what you are looking for. There are even websites that specialize in providing students with papers. The task of plagiarizing from the internet has become so popular that according to a survey found in Education Week, ≠¥54% of students admitted to plagiarizing from the internet≠¤ (≠¥Statistics≠¤ 1). The commonness of plagiarizing has grown so much from past decades that is becoming hard to control. Although, plagiarism has become so easily accomplished, the same can not be said for catching plagiarists. There is just too much information of the World Wide Web, that it makes it almost impossible for plagiarists to be caught in the act.

How Does James Seek to Disturb and Involv Essay

How Does James Seek To Disturb and Involve The Reader In The Turn Of The Screw? The Turn of the Screw, written by author Henry James, although defying many gothic conventions remains one of the most suspenseful and sinister tales of the Victorian Era. The novella’s enthralling nature effectively seeks to disturb and involve readers and this is made evident through James’s successful use of a variety of structural and literary techniques to create and prolong suspense and ambiguity. James first establishes a strong and intimate connection between reader and protagonist through the use of first person in order to actively involve the reader. This is achieved through the governess’s use of syntax and complex sentences when describing her first impressions of Bly. For example when the governess says â€Å"I remember as a thoroughly pleasant impression the broad, clear front, its open windows and fresh curtains and the pair of maids looking out† readers are provided with clear imagery of what the governess is seeing, therefore enabling readers to identify with the protagonist and view the situation from her perspective. This intimate identification with the governess later contributes to the disturbance of readers as, when the reader reaches the possible conclusion of the governesses emotional instability and tendency to catastrophise situations (when the governess says â€Å"His not reading to her, I declared, they’re talking of them, they’re talking horrors! †) readers begin questioning the governesses judgement, which for the majority of the novella has also been their own as a result of the reader being provided with a limited perception and knowledge of the happenings of Bly (as the tale has been told from the governesses viewpoint) This results in readers questioning every assumption they have previously made as they take into account the unreliability of the governess as narrator. The inclusion of ambiguous dialogue throughout the novella also contributes to the disturbance and involvement of readers by causing readers to question the true motives of characters. For instance when Miles says â€Å"of course, we’ve the others†, when speaking to the governess it is unclear whether Miles is referring to the maids and various other servants in the house or to the ghosts of Peter Quint and Miss Jessel. Another example, towards the end of the novella is when Miles and the governess are discussing Miles schooling. The governess is finally attempting to piece together the reason for Miles’ expulsion from boarding school when Miles says â€Å"Well-I said things†. This causes the reader to question the true meaning of dialogue, forcing the reader to draw their own conclusions and opinions based on limited and somewhat flimsy evidence. This therefore leads to judgements on the motives and reliability of characters being made and subsequently impacts on the readers personal opinions of characters, in especial the protagonist as well as the characters of the children, Mrs Grose and the ghosts themselves. It is important to note the use of ambiguous dialogue (or lack thereof) between Miles and Flora, particularly in the first half of the novella significantly contributes to the validity of the governess’s theory of Miles and Flora being corrupt. By not supplying the reader with dialogue between Flora and Miles it is assumed by the reader that the children are communicating in private, and as a consequence have something to hide, further validating the governess’s theory and sparking a sense of fear in readers. The further involvement and disturbance of the reader is instigated by James’s inclusion of long pauses and gaps in dialogue to further the tales suspenseful atmosphere and in turn, draw readers in. When Miles says to the governess â€Å"think me-for a change-bad! † the pauses in between his dialogue heighten the mounting suspense and ambiguity of the moment, in turn disturbing and distressing the reader. A further example of this is when, during a discussion of the relationship between Peter Quint and Miss Jessel between the governess and Mrs Grose, Mrs Grose says â€Å"oh he couldn’t prevent-â€Å". The governess then interjects with the dialogue and rhetorical question of, â€Å"Your learning the truth? †. This interjectory on the governesses part contributes to the ominous nature of the novella and further disturbs and concerns the reader through leaving the reader with an unanswered question which readers are then forced to draw their own conclusions on. The pauses and use of rhetorical questions also allows the reader time to ponder underlying questions and possible motives of characters (such as that of Mrs Grose and her part in the tale) and whilst actively engaging the reader, encourages them to anticipate the ‘next turn of the screw’. An additional way the novella seeks to horrify and capture the attention of readers is through plot and the ‘hooks’ at the end of each sequential chapter. The governess’s unnatural desire to control the children fascinates and involves the reader as they continue to question the sanity of the governess and, simultaneously the nature of the children. This desire of the protagonist is conveyed to readers through the actions and dialogue of the governess such as when she listens at Mile’s bedroom door during the night and says â€Å"what under my endless obsession, I had been impelled to listen for was some betrayal of his not being at rest†. Actions and ambiguous dialogue such as this disturbs the reader as it is regarded to all, (except the governess) as strange behaviour and acts as further proof of the probable insanity and overactive imagination of the governess. The ‘hooks’ at the end of each chapter are yet another way James uses plot to involve the reader and seeks to disturb them. These hooks or revelations by the narrator act as ambiguous snippets of information that is vitally important to the reader in order for some sort of conclusion or opinion to be reached. For instance at the conclusion of chapter 19 the governess finally voices her theory of Flora being in communication with Miss Jessel to Flora herself when she says â€Å"Where, my pet, is Miss Jessel? †. This creates a sense of terror and anxiety in readers as James has carefully built up suspense through plot to this moment and so ambiguity is at its peak when the governess finally voices her theory to Flora. The use of juxtapositions and hyperbole throughout the descriptive and emotive language of the governess is yet another way James strives to disturb and involve. The descriptive language and passion with which the governess tends to use to describe Flora and Miles, for example â€Å"I was dazzled by their loveliness†, â€Å"real rose-flush of his innocence† and â€Å"he was therefore an angel† makes the later revelation of the children’s corruption caused by the ghosts all the more disturbing and surprising to readers as the children are written about in such a pure and angelic light. This captures the attention of the reader and causes them to question the theory of the children’s corruption and consider the evidence (or lack thereof) from which it has been convened. The juxtaposition â€Å"to gaze into the depths of blue of the child’s eyes and pronounce their loveliness a trick of premature cunning† is another example of how James uses descriptive language to convey the emotional stress of the protagonist to readers as this is a strong contrast to the governess’s initial views of the children as being of â€Å"angelic nature†. â€Å"I seemed to see in the beautiful face with which he watched me how ugly and queer I looked† again contrasts the beauty of Miles with that of the governess and so draws the attention of the reader to the governesses  tendency to be easily influenced by appearance, evidence of her own innocence, inexperience and naivety which could possibly contribute to her overactive imagination and hallucinations. Setting is a superfluous method to which James meritoriously pioneers to disturb and involve the reader. The in depth descriptions used to create imagery for readers of the protagonists environment is a powerful method used by James in capturing the attention of readers and providing them with a window to the governess’s thoughts. â€Å"Driving at that hour, on a lovely day, through a country, the summer sweetness of which served as a friendly welcome† is an example of how setting is used to inform readers of the governesses opinions and inner feelings (here she feels relaxed and excited for her arrival at Bly) In addition â€Å"It was a crisp, clear day, the first of its order for some time, the night had brought a touch of frost and the autumn air, bright and sharp† is another excellent example of how James uses setting to establish the mood and atmosphere of the novella and of the governess and therefore actively involve the reader by causing the reader to feel they are more than an objective viewer but an actual participant in the tale. The use of the adjectives â€Å"crisp† and â€Å"clear† could also possibly convey the emotional state of the governess and consequently contribute to the later disturbance of the reader as the emotional state of the protagonist recedes further and further into turmoil and chaos. It is evident, throughout the Turn of the Screw Henry James has pioneered a variety of both structural and literary methods to seek to disturb and involve the reader. By doing this James has allowed his tale to remain a classic one that can relate in almost every society and time period as it continues to force readers to reach their own conclusions and subsequently, allows the novella to remain a mystery for all those involved.

Frederick Douglass’s Slave Narrative Authenticity Essay

ROUGH DRAFT Storytelling has always been prominent among the human race ever since the oral tradition was established and the first written language came to be. It is not uncommon for a person to share their experiences, feelings, and thoughts through literature. The validity of these accounts often are not questioned. In 1845, Frederick Douglass published his autobiography, Narrative of the Life of Frederick Douglass, an American Slave.Through writing and word of mouth, Douglass achieved international fame. Despite all of this, the validity of the slave narrative genre has come into question. Skeptics and naysayers claim that this genre of writing is fantasized, and use Olaudah Equiano’s narrative as a prime example. Although The Interesting Narrative of the Life of Olaudah Equiano has questionable history validity; Douglass’ writings have been affirmed by William Lloyd Garrison, a prominent American abolitionist, in the preface.It has also been published and categoriz ed as an autobiography. Accordingly, it is established that Douglass’ writing is non-fiction, therefore, it must be authentic. Being that the narrative was prefaced by William Lloyd Garrison, an exceptionally outspoken anti-slavery advocate, and author of William Lloyd Garrison and the Fight against Slavery, it would be almost impossible to claim that Frederick Douglass’ claims were falsified.Garrison indited, â€Å"I am confident that is it essentially true in all its statements; that nothing has been set down in malice, nothing exaggerated, nothing drawn from imagination; that it comes short of the reality, rather than overstates a single fact in regard to SLAVERY AS IT IS† which conveys that he had complete and total trust towards Douglass (Which is a good display of character on Douglass’ behalf). Therefore, William Lloyd Garrison’s regard for Frederick Douglass does nothing but further prove the believability of Douglass’ auto-biography .The authenticity of Narrative of the Life of Frederick Douglass, an American Slave is also substantiated by the writing being categorized as an autobiography. As things go, auto-biographies are considered to be non-fiction. If Douglass’ writings were untrue, it would be relatively easy to disprove his written accounts because of all of the factual information required in order to produce an autobiography. Frederick Douglass is also credited with the writing of his second autobiography, My Bondage and MyFreedom(1855), and his third, The Life and Times of Frederick Douglass(1881). The print is comprised of detailed experiences, places, people, and events that are historically accurate. Because of this, Douglass’ experiences are considered to be factual information. By the same token, Frederick Douglass’ first autobiography was also a published work. Douglass’ Narrative of the Life of Frederick Douglass, an American Slave went through the process of publica tion in 1845, and was ultimately published by the American Anti-Slavery Society.In order to publish a non-fictional piece of literature, the piece must be—non-fictional. In the best interest of authors and publishers alike; it would be nonsensical to compose and publish a fictional text and write it off as a work of non-fiction. Considering that the memoir received publication status, it is established that the publisher did not see it as a risk to their good name, and that Narrative of the Life of Frederick Douglass, an American Slave is authentic. In essence, Frederick Douglass’ piece is undoubtedly unbiased, authentic, and legitimate.The Narrative of the Life of Frederick Douglass, an American Slave was not only published & categorized as an autobiography, but it was also endorsed by a high-principled source, William Lloyd Garrison. Many Caucasian autobiographies of the 17th-18th century are not besieged with criticism, such as Daniel Defoe’s Mother Ross: The Life and Adventures of Mrs. Christian Davies, Commonly Called Mother Ross, on Campaign with the Duke of Marlborough(1740). It could be possible that the criticism of the slave narrative genre is truly a form of discrimination, rather than genuine mistrust.