The Use of X-Rays in Dentistry Essay Example for Free

The Use of X-Rays in Dentistry Essay Dentistry is increasingly becoming a major part of people lives in today’s society, being taken for granted and often little thought about. As technologies advance treatment becomes cheaper, quicker, and the outcome becomes more aesthetically pleasing and longer lasting. As braces, dentures, crowns, procedures and techniques change and improve at an alarming rate, one aspect has remained the same for a longer period of time. This is the use of X-Rays. X-Rays have been used in dentistry since the mid 1900’s, and continue to be used in the same way today. They are an effective way of finding and identifying various oral problems, allowing for early prognosis and prevention of more serious issues. How is an x-ray produced? Diagram showing a Dental x-ray tube. In a dental (and most other uses of x-rays including all medical uses) x-ray tube, x-rays are formed as electrons from a hot wire filament are accelerated onto a target anode. A high-voltage unit is used to set the anode at a large positive potential compared to the negatively charged filament. The electrons are pulled onto the anode at very high speeds and are suddenly decelerated on impact. As this impact occurs, some of the kinetic energy is converted into electromagnetic energy, as x-rays. This means that the anode therefore emits x-rays as a result of being smashed with high-energy electrons. The x-rays spread out from the focal spot, through the tube window and onto the region to be examined. How is an image formed? X-ray films that are used in dental radiography consist on an emulsion/gelatine mix containing chemicals that are sensitive to x-ray radiation. This is a silver halide either bromide or chloride. The emulsion/gelatine mix and their suspension is set onto a flexible, transparent tinted blue base. Emulsion is used in all types of analogue photography, but the type used in x-ray photography is of a different kind to that used in light photography. The emulsion is usually coated on both sides of the base in layers around 0. 1mm thick. As both sides of the base are coated, there is twice the amount of radiation sensitive silver halide, and so the speed at which an image is produced is increased significantly. Another way to increase the speed of producing an image would be to just have one side with a larger thickness of emulsion. This however would slow down the developing, fixing and drying stage, meaning taking x-rays would take an unreasonable amount of time. Some x-rays requiring more detail use film with emulsion on one side only. When x-rays, gamma rays, or light strike the grains of the sensitive silver halide in the emulsion, some of the halide (Br- or Cl-)  ions are released and captured by the silver (Ag+)ions. This chemical change is of such a small nature that it cannot be detected by ordinary physical methods and is called a latent (meaning hidden) image. However, the exposed grains are now more sensitive to the reduction process which happens during development of the film. When exposed to a chemical solution (the ‘developer’), and the reaction results in the formation of black, metallic silver. It is this silver, suspended in the emulsion-gelatine on both sides of the base that creates an image. Seeing things with X-Rays Different materials have different properties, including x-ray absorption ability. This is exactly the same with body parts, especially teeth. Radiation passes through skin the easiest, followed by the guns and soft tissue. These parts show up as the very darkest areas on an x-ray. Harder tissues absorb and black more radiation from hitting the film and so show up as much lighter areas. Metal implants, fillings and crowns (most artificial features) show up as the brightest white. The different depths of materials is also shown, nerve endings and dentine contours being visible on most developed films. This image shows that a root canal procedure has been successfully completed, meaning less time and money is wasted fixing procedures that have failed. Also visible is an amalgam filling (Brightest white) Measuring Radiation The Sievert The  sievert  (Sv) is the  International System of Units  (SI)  derived unit  of  equivalent radiation dose,  effective dose, and  committed dose. Quantities that are measured in sieverts are designed to represent the  stochastic  biological effects of  ionizing radiation. The sievert should not be used to express the unmodified  absorbed dose  of radiation energy, which is a clear physical quantity measured in  Grays. To enable consideration of biological effects, further calculations must be performed to convert absorbed dose into effective dose, the details of which depend on the biological context. This can be far more complicated than just multiplying by a weighting factor. The sievert is a fundamental part in  radiation dosimetry, and is named after  Rolf Maximilian Sievert, a  Swedish  medical physicist renowned for work on radiation dosage measurement and research into the biological effects of radiation. One sievert equals 100  rem, an older unit of measurement still used in many areas and by older generations of practitioners. One sievert carries with it a 5. 5% chance of eventually developing cancer. Doses greater than one sievert received over a short time period are likely to cause  radiation poisoning, possibly leading to death within weeks. This is a major risk considered in dental use as many doses of radiation could be received during a day in surgery.

Mythology Of Indian Dance :: essays research papers

Like many Indian arts, Indian dance also has its root in religion. Without the religious and cultural background of India, the growth and beauty of Indian dance is not possible. In ‘Natya Shastra’, there is a small story about the origin of Indian dance. According to Hindu mythology, dance first existed in heaven. There was always a constant conflict between the Asuras and the Devas for wealth and power. The Devas were tired of the Asuras’ greediness and jealousy.   Ã‚  Ã‚  Ã‚  Ã‚  It was during this long period of tedium that all the Devas approached Lord Indra too find good ways and means of entertainment. Lord Indra, who was also tired of the Asuras, approached Lord Brahma (believed to be the creator of the Universe) and asked him to help them. They made a request to Lord Brahma that this method of entertainment should be pleasing to both the eye as well as the ear, and that it should be enjoyed by the masses of both higher and lower classes. Lord Brahma gave a long thought to the request of Lord Indra and finally decided to help them.   Ã‚  Ã‚  Ã‚  Ã‚  Lord Brahma went into a state of deep meditation. He called to mind the four Vedas. Vedas are the earliest scriptures of the Hindus. He distilled the essence from each of the Vedas. From ‘Rigveda’, he derived the words, from ‘Sama Veda’, he derived the music, from ‘Yojurve Veda’, the code of gesture and from ‘Atherva Veda’, the element of sentiment or flavor. He blended all of these ingredients and added his own divine genious. Thus, he created an entirely new activity. Brahma named this activity ‘Natya’, which was later renamed ‘Natya Veda’.   Ã‚  Ã‚  Ã‚  Ã‚  Brahma had simply created a technique, but someone was needed for putting it into practice. Lord Brahma sought the cooperation of Bharat, a trusted sage. Bharat, with the help of his sons, started working. Vishvakarma, the supreme architect of heaven, then created a splendid theater in the hall of India’s court for the performance. Bharat told Brahma that certain characters of the dance sequences could only be performed by women. Brahma solved the problem by creating twenty-three beautiful ‘Apsaras’.   Ã‚  Ã‚  Ã‚  Ã‚  All of the preparations were made accordingly, and for the very first time, the art of ‘Natya’ was performed before an audience of Devas and Asuras. In this Natya, the Devas were portrayed as victorious and the Asuras as losers. The Asuras (demons) got angry and rose in protest and threatened even worse consequences.

Lord of the Flies Thesis Paper

Being stranded on an island can be a life or death struggle. It brings up new challenges and self discovery. When a group of young boys get stranded on an island together with no adults, they must learn to live and survive as a community. Not only must they worry about food and shelter, but they also have to worry about each other and discover what it takes to work together. But what happens when the community they have built starts to fall apart?In Golding’s Novel, Lord of the Flies, the contrasting literary themes of civilization versus savagery are illustrated through the use of symbols, dialogue, and visual imagery. Golding uses many symbols throughout his novel to illustrate the contrasting themes of civilization versus savagery. In this novel, the use of the conch represents civilization through unity and order. When the boys first land on the island Ralph uses the conch to join everyone together. â€Å"Signs of life were visible now on the beach.The sand, trembling ben eath the heat haze, concealed many figures in its miles of length; boys were making their way to the platform†¦Ã¢â‚¬  (Golding 18). This shows that at the beginning, the conch automatically brought everyone together, and joined them as a community. Later in the story, the lord of the flies represents savagery by symbolizing chaos and disorder. After the boys kill a pig, they leave the head as on offering to the imagined beast. As Simon begins talking to the head, it tells him that it itself is the beast.Later, Ralph encounters the skull of the pig. â€Å"A sick fear and rage swept him. Fiercely he hit out at the filthy thing in front of him that bobbed like a toy and came back, still grinning into his face, so that he lashed and cried out in loathing. † (Golding 185). This shows that the lord of the flies brings out the beast in the children themselves, and shows that all along, they in fact were their own beast. Golding also uses pieces of dialogue to illustrate the co ntrasting themes of civilization versus savagery.In the very beginning, Piggy proves to be the most knowledgeable of the group by trying to keep them civilized and orderly. When the group is talking about building a signal fire to be rescued, Piggy says, â€Å"’How can you expect to be rescued if you don’t put first things first and act proper? ’† (Golding 45). This shows that from the very beginning Piggy thinks there should be order and a clear plan for anything successful to happen on the island. Also around this time, the theme of savagery through dialogue begins with Jack.After hunting for the first time, Jack explains to Ralph that he sent his group back while he continued to hunt by himself. â€Å"’I went on,’ said Jack. ‘I let them go. I had to go to go on. I—‘ He tried to convey the compulsion to track down and kill that was swallowing him up. ‘I went on. I thought by myself—‘ The madness came into his eyes again. ‘I thought I might kill. ’† (Golding 51). This is the beginning of Jack’s transformation from civilized to savage. At this time, killing becomes his priority over all else.Lastly, Golding uses visual imagery throughout his novel to illustrate the contrasting themes of civilization versus savagery. In the beginning, Golding uses visual imagery to represent civilization when Ralph uses the conch to unite everyone together. â€Å"At last Ralph ceased to blow and sat there, the conch trailing from one hand, his head bowed on his knees. As the echoes died away so did the laughter, and there was silence. † (Golding 19). This shows that at the beginning, everyone came together in a civilized manner and was silent so that they could listen to the further conversations that were had.Later, Golding uses visual imagery to represent savagery during the killing of Simon. â€Å"The beast struggled forward, broke the ring, and fell over the st eep edge of the rock to the sand by the water. At once the crowd surged after it, poured down the rock, leapt on to the beast, screamed, struck, bit, tore. There were no words, and no movements but the tearing of teeth and claws. † (Golding 153). This shows that by this point, the only thing the boys cared about was hunting and they would hunt anything they could.This act was only the beginning of murder in this story, and later led to the murder of other boys. In Golding’s Novel, Lord of the Flies, the contrasting literary themes of civilization versus savagery are illustrated through the use of symbols, dialogue, and visual imagery. Though in the beginning many things joined the boys together on the island, in the end, things tore them apart more than could be recovered. Overall, this book conveys the collapse of society in the world through chaos, cruelty, and the lack of leadership and order.

Populist Ideas Spread Through All Of Latin America

In the past couple of decades, populist ideas spread through all of Latin America. First, Cuba adopted these ideals with the arrival of Fidel Castro to power in 1959. Then, Hugo R. Chavez adopted Cuban ideals in Venezuela in 1998. Since Venezuela adopted populism, it spread quickly throughout countries in South America. All of the countries that adopted populism deteriorated throughout the years reaching a point of social unrest. Populist governments like Chavism are prejudiced to the country and its citizens. In Venezuela, Chavism led to ridiculous crime rates, huge monetary devaluation, corruption inside the government, famine, and social unhappiness. As stated by the article â€Å"A Political Theory of Populism†, populism is â€Å"a democratic discourse that relies on the idea of a popular will and struggle between  ´the people ´ and  ´the elite ´Ã¢â‚¬â€ then Chavismo is clearly a populist phenomenon† (Acemoglu 1). Populism is the shortcut that the government uses to play with the passions, illusions, and ideals of its citizens with the purpose of promoting what is impossible and taking advantage of people’s misery. Populist governments avoid using reason and logic when making decisions and they play with the basic necessities of people to simply impose a dictatorship. The effects of populism in a country are devastating and you can observe the deterioration of Venezuela throughout the seventeen years of Chavism. Gloria Alvarez in her interview states that â€Å"the immediate effects ofShow MoreRelatedMedia s Influence On Society s Emotions And Opinions1517 Words   |  7 Pagesreflecting their ide as through the mass communication epidemic. The article â€Å"Broadcasting Populist Leadership: Hugo Chà ¡vez and Alà ³ Presidente† was written by Eduardo Frajman and published in the Journal of Latin America in August 2014. 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