Macro systems paper Essay Example | Topics and Well Written Essays - 1250 words

Macro systems paper - Essay Example For one to understand human services interactions in terms of macro systems communities and organizations there should be an initial understanding of the concept of personal, interpersonal, and political empowerment. Personal empowerment can be referred to as an individual’s ability to have an effect on events and the people in their environment. Personal empowerment is usually enhanced with an individual’s ability to comprehend their current position and exactly where they are headed to (Van, Keefe &Besthorn, 2007). Personal empowerment is also characterized by an individual’s flexibility and their ability to change in accordance to their environment. Interpersonal empowerment is always used with reference to an individual’s ability to work collaboratively with other people to effectively implement plans that are put in place for them to implement. This is always characterized by the existence of interpersonal skills. A person who is interpersonally empowered can, therefore, be said to be someone who can effectively function as part of a team. Political empowerment occurs when the government offers help to communities and institution with the aim of making their lives less challenging. It also occurs when the government allows communities and organizations to have political participation in political issues that have either direct or indirect influence on their existence (Kirst-Ashman, 2008). Politicalempowerment enables the public to make sure that they are able to influence political decision making in the best way possible. An individual can always involve themselves in multiple systems at a working environment. These systems include: micro, mezzo, and macro systems. At the micro level and individual usually focuses on having personal interactions with their clients individually or with a family member or spouse. Interventions at this level can include an individual interacting with the client in a number of occasions.

Race and Ethnicity Essay Example for Free

Race and Ethnicity Essay Until now talk of â€Å"race† and â€Å"ethnicity† still remains a sensitive issue and despite many attempts, discrimination still exists in our modern society. But, on the throes of a multiracial decade, we might be on track to finally understand that race is really a social creation. The website Race: Are We So Different? (http://www. understandingrace. org/home. html) helps shed light into this issue by providing interactive programs, like the Human Variation Quiz, that make it easier for people to understand the â€Å"race issue† in layman’s terms. After taking the quiz, it became clear to me that, yes, race is just embedded in our society and cannot be traced to our genetics or lineage. It gives out facts that correct our idea of what defines race. They tell us that, say, physical qualities that can be attributed to genetics cannot be categorized into the three or four races that people today recognize. Rather, study of our DNA even shows that there might be more genetic differences between two Latin Americans than between a Latin American and a Caucasian American. The documentary Race: The Power of Illusion also shows this when during a DNA workshop, led by forensic expert Scott Bronson, a group of teenagers from different lineages found out that they have more in common with other people from other â€Å"races† than their own. As Peter Wade mentions in his book Race and Ethnicity in Latin America (1997), biologically speaking, race does not exist (Wade 13). It is, therefore, a socially-constructed idea that actually changes with time. Most importantly, the quiz shows that if we track down our DNA to one source it can be traced to a human community that settled in Africa 100,000 years ago, showing that everyone of Earth comes from one community, one people. The problem that we should look into now is how as a society we can change this idea of different races into an understanding of one race. Scholars say that it involves a huge â€Å"paradigm shift†, like how humans began to see the world as round than flat. What I say is, no matter how big it is I believe we are definitely ready.

Bacteria on Stainless Steel Surfaces | Experiment

Bacteria on Stainless Steel Surfaces | Experiment The attachment of bacteria on food processing surfaces and in the environment can cause potential cross-contamination, which can lead to food spoilage, possible food safety concerns, and surface destruction. Food contact surfaces used for food handling, storage or processing are areas where microbial contamination commonly occurs. Even with proper cleaning and sanitation regimes or practices in place, bacteria can remain attached to the surfaces and this attachment can lead to biofilm formation. The purpose of this study was to identify the presence of pathogenic microorganism in a food processing area and to evaluate the effect of the cleaning procedure on the microbial load in the food processing area. Ten replicate food contact surfaces were tested: stainless steel, marble and wood, with adjacent areas being sampled before and after cleaning. The test surfaces were analyzed with a swab method before and after the cleaning stage. The results of these studies indicate that three of ten stainless steel surface were contaminated before cleaning and no surface was contaminated after cleaning. Furthermore, three out of ten marble surfaces were contaminated before cleaning and one surface was contaminated after cleaning. Six of ten wood surfaces were heavily contaminated before cleaning and three surfaces were contaminated after cleaning. The difficulty in cleaning was related to the amount of surface damage and it is best to avoid this type of surface. Hypochlorite solution that was used for cleaning the surfaces in this study was considered to be effective against the foodborne pathogens tested. This study has highlighted the fact that pathogens remain viable on dry stainless steel surfaces and present a contamination hazard for considerable periods of time, dependent on the contamination levels and type of pathogen. Keywords: Microorganisms; Survival; Cross-contamination; Food contact surface Introduction Food contact surfaces are the chief denizen of biofilm that can host potentially harmful microorganisms. This, therefore, is a prominent phenomenon in food processing plants owing to dregs and residues of all sorts chemical, biological, organic, and/or inorganic -which build up on the surfaces of equipments that may get in contact with food (Mafu et al. 2010). The presence of these undesirable microorganisms to the material surfaces is a source of concern, as this can result in food cross-contamination, leading to food poisoning. Under favourable circumstances (temperature, pH, relative humidity), pathogenic microorganisms are able to survive and/or replicate on a large scale within the biofilm. In domestic kitchens and food processing industries, foodborne illness can result from incorrect storage of foods, particularly with respect to temperature, contamination of raw or cooked foods before consumption, by contact with other foods or utensils (food contact surfaces ) carrying path ogens, and inadequate cleaning procedures that may not see complete removal of microorganisms (Teixeira et al. 2007). In food processing industries, food contact surfaces, such as stainless steel, marble and wood may create an enabling environment for the survival of the microorganism, leading to serious hygienic problems. Furthermore, dead ends, corners, joints, valves and any other hard-to-reach places are the most appropriate areas for the presence of bacteria. (Peng et al. 2001). The value of maintenance and disinfection processes in food processing industries depends, to a large extent, on the design and maintenance programmes adopted by the company. Lack of efficacy in cleaning procedures may allow persistence and survival of pathogens in foods owing to their consistent adherence to food contact surfaces. This may lead to transfer of microorganisms from people, objects or contaminated food to other food or material, hence leading to cross-contamination. People can, in many ways, be a source of cross-contamination to foods (Holah and Thorpe, 1990). Food can be contaminated when it is handled, so it is very important that people who may be carrying or suffering from certain diseases do not handle food. Contamination can also be passed from equipment when contacting food. It specifically happens when utensils or equipment are not efficiently cleaned and sanitized between each use and may lead to development of biofilm, creating favourable conditions for the survival of the pathogens. Contamination from food to food occurs mainly when raw foods come into contact with cooked or prepared foods (Montville et al. 2001). The persistent presence of microorganisms in food processing factories, specifically on food contact surfaces despite deliberate efforts to combat the phenomenon, poses great challenges to the company. It reduces the profit margins of the industries due to the increased cost incurred in the attempts to adopt advanced cleaning services and programmes. A potential effect of the presence of microorganisms on food surfaces is food poisoning. Occurrence of food poisoning will mean great damage to the image of the company and persistent stress on the part of the management, thus derailing the progress of the company. Cross contamination is also becoming a common problem both in the kitchen setting and in industry. Transfer of resistant pathogens and microorganisms across and around these food producers through various agents and factors that propagate and carry the pathogens is a health hazard. Studies show that the level of contamination varies depending on the duplication and the rate of material handling that occurs in the factory. In this context, therefore, workersà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒ ¢Ã¢â‚¬Å¾Ã‚ ¢ hands, utensils and the broad extension of all food contact surfaces contribute to in cross contamination (Zhao et al. 1998). A thorough examination of the whole concept of microbial survival and persistence on food contact surfaces despite typical cleaning procedures and revised designs of the food contact surfaces (such as textural properties, maintained solid surface hydrophobicity) will reveal that more detailed analysis and studies should be focused on the factors that create an enabling environment for the persistent replication and presence of the foodborne pathogens in the food processing industries and kitchen setting (Scott and Bloomfield, 1990). The study of various relevant properties for the microbial adhesion process has been another imperative goal of this study and the purpose behind it is to obtain a broader knowledge base of the mechanisms of bacterial adhesion to food contact surfaces so as to formulate strategies for its control. The objective of this study is to identify the microorganisms that can survive in the food contact surface, such as stainless steel, marble and wood, even after cleaning procedures, thus increasing the risk of food cross-contamination. The study will focus on microorganisms that survive in the food processing areas even after the cleaning procedure. Foodborne pathogenic bacteria adhere to inert surfaces; they may exhibit a greater scale of resistance to chemical or ordinary cleaning and fumigating agents (Barnes et al. 1999). The concept of cross contamination is of major concern in the food processing industries that constitute a threat to human health because they cause most food borne illness outbreaks. Food poisoning is one of the consequences of adherence of microorganisms to food contact surfaces (Sattar et al. 2001). Materials and Methods Premises In order to assess the microbiological safety of a food processing area in Oman, three types of food contact surfaces were studied: Stainless steel, marble and wood. Ten surfaces of each of the three types were tested, with the adjacent areas of each one being sampled before and after cleaning. This study was performed randomly in nineteen selected Army camps kitchen. Data analysis Swabs were taken from the food processing area within the Royal Army camps kitchen and sent to the food microbiology laboratory of the environmental of health unit for analysis. The swabs were each tested for pathogenic bacteria linked with food and coliforms that can survive on the surface of food preparation areas before and after cleaning. The plates were read for the number of colonies of pathogenic bacteria and coliforms. A Phoenix machine was used to identify the bacteria and readings were taken directly from the Phoenix machine. A Phoenix is automated microbiology system is intended to provide rapid identification results for most aerobic and facultative anaerobic Gram positive bacteria as well as most aerobic and facultative anaerobic Gram negative bacteria. The identification of the Phoeonix panal uses a series of conventional, chromogenic and fluorogenic biochemical tests to identify the organism. The growth-based and enzymatic substrates are employed to cover the different types of reactivity among the range of taxa. The tests are based on the use of bacteria and deterioration of specific substrates detected by different indicator systems. Acid production is indicated by a change in phenol red indicator when an isolate is able to utilize a carbohydrate substrate. A yellow colour is produce by Chromogenic substrates upon enzymatic hydrolysis and the enzymatic hydrolysis of fluorogenic substrates results in the release of a fluorescent coumarin derivation. Organisms that utilize a specific carbon source reduce the resazurine based indicator. These results were recorded and the log reduction was calculated for each plate at each dilution rate after and before cleaning of the surface (BD Phoenix, 2007). Sampling methods and microbiological examination (Before Cleaning) Tests using the swab method were carried out on surfaces contaminated with food borne pathogens in a food processing area. Tubes containing 10 ml of sterile buffered peptone saline solution were used to wet the swabs prior to sampling. Cotton swabs were removed from their sterile packaging and were held by the stick while they were moistened with buffered peptone saline solution, the excess broth was returned into the bottle. All surfaces were prepared in sizes of 20 x 20 cm2 for survival experiments. The swabs were rotated while in contact with the food preparation surface. After the defined area was swabbed, the swab was returned to the test tube containing the buffered peptone saline solution to dislodge the bacteria. Serial dilutions of the swab solutions were prepared and duplicate pour plates were prepared for each dilution using nutrient agar, MacConkey agar and Blood agar. The plates were incubated for 24 hours at 37oC. Sampling methods and microbiological examination (After Cleaning) The surfaces were washed with hot water and chemical detergent and then rinsed with hot water. Then the surfaces (stainless steel, marble, and wood) were disinfected with 5.25% of hypochlorite solution for 10 minutes. The surfaces were allowed to dry before sampling. The swabbing method used was as above. Duplicate pour plates were prepared for each dilution using nutrient agar, MacConkey agar and Blood agar. The plates were incubated for 24 hours at 37oC. Sampling methods and microbiological examination (Control) Some of the food borne pathogen strains used as a control for these experiments on the surfaces (stainless steel, marble, and wood), such as Staphylococcus aureus and Escherichia coli were obtained from the Armed Forces Hospital Laboratory. For their control strains a clean stainless steel table without tiny groove was prepared as the food contact surface because it can be fabricated with a smooth cleanable finish. The table also was disinfected with 5.25 % of hypochlorite solution for 10 minutes. The surface was then washed with hot water, with chemical detergent and rinsed with hot water. The surface was allowed to dry before sampling. The test suspensions were prepared by making serial dilutions of the microorganisms in peptone saline solution. Two different levels of contamination were prepared: high contamination (approximately 106 colony forming units (CFU)/100 cm2) and low contamination (approximately 103 CFU/100 cm2), obtained by spreading 1 ml of an appropriate solution on a surface of 20 x 20 cm2 over the grid reference table. The table was allowed to dry for 15 minutes to represent the environment of food preparation area. Selective agar media were used for the enumeration of pathogens: Blood agar for Staphylococcus aureus, incubated for 24 hours at 37oC and MacConkey agar for Escherichia coli incubated for 18 à ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬ 24 hours at 37oC. Furthermore, the effects of two different contamination levels on the survival of pathogens on dry stainless steel surfaces for 24 hours at room temperature were investigated. Result Microbial survival on food contact surface (stainless steel surface) Table 1: The Colony descriptions of the microbial survival on stainless steel surface Table 1 shows the Colony descriptions result of the microorganisms isolated from stainless steel surface. Three of ten stainless steel surface were contaminated with bacteria before cleaning. Table 2: The colony count of the microbial survival on stainless steel Sample No. Serial ten-fold dilutions in deionised water diluents colony count (CFU ml-1) before cleaning colony count (CFU ml-1) After cleaning 2 3.2 x 102 Bacteria Not Detected 6 2.6 x 102 Bacteria Not Detected 9 4.3 x 102 Bacteria Not Detected Table 2 shows the result of the colony count obtained before and after cleaning of the stainless steel surface. Table 3: Gram stain result of the microbial survival on stainless steel surface Sample No.:  2 Gram stain result:  Gram negative, rod shape Sample No.:  6 Gram stain result:  Gram positive cocci Sample No.:  9 Gram stain result:  Gram negative, rod shape Table 3 show the result of the Gram stain of bacteria that were isolated from the stainless steel surface before and after the cleaning stage. Sample No.:  2 Sample No. In phoenix machine:  344 Name of Bacteria detected before cleaning:  Klebsiella aerogenes Name of Bacteria detected After cleaning:  Not detected Sample No.:  6 Sample No. In phoenix machine:  367 Name of Bacteria detected before cleaning:  Staphlococcus aureus Name of Bacteria detected After cleaning:  Not detected Sample No.:  9 Sample No. In phoenix machine:  382 Name of Bacteria detected before cleaning:  Klebsiella aerogenes Name of Bacteria detected After cleaning:  Not detected Table 4: The Identification of bacteria by phoenix machine that survived on the stainless steel surface before the cleaning stage Table 4 show the result of bacterial identification that obtained by phoenix machine which was isolated from stainless steel surface before and after the cleaning stage. Microbial survival in food contact surface (Marble surface) Table 5: The Colony descriptions of the microbial survival on marble surface Sample of location No.:  1 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  2 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  3 Nutrient agar:  No Growth MacConkey agar:  Pink in colour, mucoid Blood agar:  white, large and mucous colonies Sample of location No.:  4 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  5 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  smooth, round, grayish-white colonies Sample of location No.:  6 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  7 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  8 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  9 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample of location No.:  10 Nutrient agar:  Small circular colonies, yellow in colour MacConkey agar:  No Growth Blood agar:  swarming motility Table 5 shows the colony descriptions result of the microorganisms isolated from the marble surface. Three of ten marble surfaces remained contaminated with bacteria before and after cleaning. Table 6: The colony count of the microbial survival on marble surface Serial dilutions in deionised water diluents colony count (CFU ml-1) before cleaning colony count (CFU ml-1) After cleaning Sample No.:  3 *TFTC Bacteria Not Detected Sample No.:  5 5.1 x 102 Bacteria Not Detected Sample No.:  10 #TMTC TMTC *TFTC: Too Few To Count #TMTC: Too Many To Count Table 6 shows the result of the colony count obtained before and after cleaning stage of marble surface. Table 7: Gram stain result of the microbial survival on marble surface Sample No.:  3 Gram stain result:  Gram negative, rod shape Sample No.:  5 Gram stain result:  Gram negative, rod shape Sample No.:  10 Gram stain result:  Gram negative, rod shape Table 7 show the result of the Gram stain of bacteria that was isolated from the marble surface before and after the cleaning stage. Table 8: The Identification of bacteria by phoenix machine that survived on the marble surface before the cleaning stage Sample No.:  3 Sample No. In phoenix machine:  301 Marble Name of Bacteria detected before cleaning:  Klebsiella pneumonia Name of Bacteria detected After cleaning:  Not Detected Sample No.:  5 Sample No. In phoenix machine:  326 Marble Name of Bacteria detected before cleaning:  Yersinia enterocolitica Name of Bacteria detected After cleaning:  Not Detected Sample No.:  10 Sample No. In phoenix machine:  381 Marble Name of Bacteria detected before cleaning:  Proteus vulgaris Name of Bacteria detected After cleaning:  Proteus vulgaris Table 8 show the result of bacterial identification that obtained by phoenix machine which was isolated from marble surface before and after the cleaning stage. Microbial survival in food contact surface (Wood surface) Table 9: The Colony descriptions of the microbial survival on wood surface Sample location No.:  1 Nutrient agar:  No Growth MacConkey agar:  Non-lactose fermenters colonies Blood agar:  White, non haemolytic colonies Sample location No.:  2 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample location No.:  3 Nutrient agar:  smooth, translucent large colonies , greenish blue growth and pigment diffuses into medium MacConkey agar:  No Growth Blood agar:  large brownish colonies Sample location No.:  4 Nutrient agar:  White, smooth, round colonies MacConkey agar:  No Growth Blood agar:  No Growth Sample location No.:  5 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample location No.:  6 Nutrient agar:  Circular, smooth, opaque colonies MacConkey agar:  No Growth Blood agar:  swarming motility Sample location No.:  7 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Sample location No.:  8 Nutrient agar:  smooth, translucent large colonies , greenish blue growth and pigment diffuses into medium MacConkey agar:  slight pink colonies Blood agar:  large brownish colonies Sample location No.:  9 Nutrient agar:  smooth, translucent large colonies , greenish blue growth and pigment diffuses into medium MacConkey agar:  slight pink colonies Blood agar:  No Growth Sample location No.:  10 Nutrient agar:  No Growth MacConkey agar:  No Growth Blood agar:  No Growth Table 9 shows the colony descriptions result of the microorganisms isolated from the wood surface. Six of ten wood surfaces remained contaminated with bacteria before and after cleaning. Table 10: The colony count of the microbial survival on wood surface Sample No.:   Serial ten-fold dilutions in deionised water diluents colony count (CFU ml-1) before cleaning colony count (CFU ml-1) After cleaning Sample No.:  1 6.4 x 102 Bacteria Not Detected Sample No.:  3 5.3 x 102 Bacteria Not Detected Sample No.:  4 2.7 x 102 Bacteria Not Detected Sample No.:  6 TMTC TMTC Sample No.:  8 1.67 x 103 2.9 x 102 Sample No.:  9 9.3 x 102 3.6 x 102 Table 10 shows the result of the colony count obtained before and after cleaning stage of wood surface. Table 11: Gram stain result of the microbial survival on wood surface Sample No.:  1 Gram stain result:  Gram negative, rod shape Sample No.:  3 Gram stain result:  Gram negative, rod shape Sample No.:  4 Gram stain result:  Gram negative, rod shape Sample No.:  6 Gram stain result:  Gram negative, rod shape Sample No.:  8 Gram stain result:  Gram negative, rod shape Sample No.:  9 Gram stain result:  Gram negative, rod shape Table 11 show the result of the Gram stain of bacteria that was isolated from the wood surface before and after the cleaning stage. Table 12: The Identification of bacteria by phoenix machine that survived on wood surface before the cleaning stage Sample No.:  1 Sample No. In phoenix machine:  86 wood Name of Bacteria detected before cleaning:  Acinetobacter baumannii Name of Bacteria detected after cleaning:  Not Detected Sample No.:  3 Sample No. In phoenix machine:  301 wood Name of Bacteria detected before cleaning:  Pseudomonas spp Name of Bacteria detected after cleaning:  Not Detected Sample No.:  4 Sample No. In phoenix machine:  326 wood Name of Bacteria detected before cleaning:  Enterobacter hafinae alvei Name of Bacteria detected after cleaning:  Not Detected Sample No.:  6 Sample No. In phoenix machine:  342 wood Name of Bacteria detected before cleaning:  Proteus vulgaris Name of Bacteria detected after cleaning:  Proteus vulgaris Sample No.:  8 Sample No. In phoenix machine:  369 wood Name of Bacteria detected before cleaning:  Pseudomonas aeruginosa Name of Bacteria detected after cleaning:  Pseudomonas aeruginosa Sample No.:  9 Sample No. In phoenix machine:  385 wood Name of Bacteria detected before cleaning:  Pseudomonas aeruginosa Name of Bacteria detected after cleaning:  Pseudomonas aeruginosa Table 12 shows the result of bacterial identification that obtained by phoenix machine which was isolated from wood surface before and after the cleaning stage. Control Table 13: Survival of Staph aureus and E.coli on stainless steel surfaces Staphylococcus aureus Escherichia coli Time of swab process after contamination High contamination level (106 colony) CFU/100 cm2 Low contamination level (103 colony) CFU/100 cm2 High contamination level (106 colony) CFU/100 cm2 Low contamination level (103 colony) CFU/100 cm2 After 15 minute 2.0 x 107 1.0 x 104 1.6 x 107 5.2 x 103 After 2 Hours 1.73 x 107 9.1 x 103 8.3 x 106 1.8 x 103 After 6 Hours 1.3 x 107 3.8 x 103 2.1 x 106 No growth After 12 Hours 5.8 x 106 No Growth No Growth No growth After 24 Hours No growth No Growth No Growth No growth Table 13 shows the survival of Staphylococcus aureus and Escherichia coli on stainless steel surfaces at room temperature (25oC) for 24 hours at two contamination level; high contamination level of (106 colony CFU/100 cm2) and Low contamination level (103 colony CFU/100 cm2). Discussion Sampling food contact surfaces is a complex problem, and the results depend on many factors, including the type of surface, the cleaning solution, the sources of contamination, and the temperature. The accuracy and reproducibility of all sampling methods are reduced when the numbers of bacteria on the surface are low. Some differences between methods are probably due to an uneven distribution of bacteria on the surface. The type of surface markedly influenced the cleaning results. For this study, nineteen selected premises were tested/studied (Ten replicate surfaces were tested; stainless steel, marble and wood, with adjacent areas being sampled before and after cleaning). The results of these studies indicate that three of ten stainless steel surfaces were contaminated before cleaning the surfaces and no surface was contaminated after cleaning, which means that stainless steel surfaces were more easily cleaned. Furthermore, three out of ten marble surfaces were contaminated before c leaning and one surface was contaminated after cleaning the surfaces, which means marble surfaces were easily cleaned but using the wrong cleaning products and the wrong cleaning techniques can damage the marble because marble is a calcium-based natural stone which is highly sensitive to acidic materials (Marble Institute of America, 2012). Stainless steel resists impact damage but is vulnerable to corrosion, while marble surfaces are prone to deterioration and may develop surface cracks where bacteria can accumulate (Leclercq and Lalande, 1994). Wood surfaces were particularly diffi

A Compare and Contrast of Thomas Moores Utopia and Machiavelli?s The Pr

Just vs. Viable   Ã‚  Ã‚  Ã‚  Ã‚  To be just is to be fair and honorable. Kids are taught that if you are kind and just you will excel and be successful. But life’s not fair and being just doesn’t necessary mean that a society will stand the test of time and be able to grow. The two different societies introduced in More’s Utopia and Machiavelli’s The Prince are very different and although More’s Utopian society would be considered more just then Machiavelli’s society. Machiavelli’s society is more realistic and more likely to be viable.   Ã‚  Ã‚  Ã‚  Ã‚  Leadership is a major issue when it comes to whether or not a society is going to be viable. It seems that if the leader is a good leader, a leader that puts his people first and wants the best for his country, then the land and the society should flourish. But if the leader is a bad leader, a power driven leader, a leader who puts himself first, and lets his people starve while he and his nobles live in excess, then the society and land will not flourish. This idea is not demonstrated to us in Utopia or The Prince; it seems like the exact opposite. Utopia has a more democratic government. Each set of households elects someone and then those elects elect others, and although there is a prince they still have the power to throw him out of office if he’s involved in any wrong doing. And although their prince doesn’t have as much power as a prince in Machiavelli’s writing the prince in Utopia serves a different purpose. The prince in Utopia is there to provide stability. With the syphogrants and tranibors changing annually the stability of a constant figure head is needed. More describes the government as follows   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"Once a year, every group of thirty households elects an official, Formerly called the syphogrant, but now called the phylarch. Over Every group of ten syphogrants with their households there is another official, once called the tranibor but now known as the head phylarch. All the syphogrants, two hundred in number, are brought together to elect the prince. They take an oath to choose the man they think best qualified; and then by secret ballot they elect they prince from among four men nominated by the people of the four sections of the city. The prince holds office for life, unless he is suspected of aiming at a t... ...s. But this society was in no way more just then the Utopian society, although this society was more viable. They had what it took to last, to grow and to flourish.   Ã‚  Ã‚  Ã‚  Ã‚  Both societies have there good points and both societies have their flaws. More imagined a new society, even though it still carried some remnants of the one he knew. And the Utopian society looked great on paper; they were very just and honorable people. But when examined in depth it falls apart. This society wouldn’t last people don’t think that way. Machiavelli criticized and critiqued history, he took things he knew and said how they could be made better for future societies. Except societies and societal ideas evolve, ideas that worked then don’t always work now. His society was based on backstabbing and deceitfulness, appearing virtuous but not actually being virtuous. So although his society would have lasted, it was far from just. But this is the opinion looking back at these texts. When these texts were written More and Machiavelli both thought these were the ideal societies. But if More and Machiavelli knew what people know now would their societal ideas still be what they were?

Part One (Olden Days)

Trespassers 12.43 As against trespassers (who, in principle, must take other people's premises and their occupiers as they find them) †¦ Charles Arnold-Baker Local Council Administration, Seventh Edition I Pagford Parish Council was, for its size, an impressive force. It met once a month in a pretty Victorian church hall, and attempts to cut its budget, annex any of its powers or absorb it into some newfangled unitary authority had been strenuously and successfully resisted for decades. Of all the local councils under the higher authority of Yarvil District Council, Pagford prided itself on being the most obstreperous, the most vocal and the most independent. Until Sunday evening, it had comprised sixteen local men and women. As the town's electorate tended to assume that a wish to serve on the Parish Council implied competence to do so, all sixteen councillors had gained their seats unopposed. Yet this amicably appointed body was currently in a state of civil war. An issue that had been causing fury and resentment in Pagford for sixty-odd years had reached a definitive phase, and factions had rallied behind two charismatic leaders. To grasp fully the cause of the dispute it was necessary to comprehend the precise depth of Pagford's dislike and mistrust of the city of Yarvil, which lay to its north. Yarvil's shops, businesses, factories, and the South West General Hospital, provided the bulk of the employment in Pagford. The small town's youths generally spent their Saturday nights in Yarvil's cinemas and nightclubs. The city had a cathedral, several parks and two enormous shopping centres, and these things were pleasant enough to visit if you had sated yourself on Pagford's superior charms. Even so, to true Pagfordians, Yarvil was little more than a necessary evil. Their attitude was symbolized by the high hill, topped by Pargetter Abbey, which blocked Yarvil from Pagford's sight, and allowed the townspeople the happy illusion that the city was many miles further away than it truly was. II It so happened that Pargetter Hill also obscured from the town's view another place, but one that Pagford had always considered particularly its own. This was Sweetlove House, an exquisite, honey-coloured Queen Anne manor, set in many acres of park and farmland. It lay within Pagford Parish, halfway between the town and Yarvil. For nearly two hundred years the house had passed smoothly from generation to generation of aristocratic Sweetloves, until finally, in the early 1900s, the family had died out. All that remained these days of the Sweetloves' long association with Pagford, was the grandest tomb in the churchyard of St Michael and All Saints, and a smattering of crests and initials over local records and buildings, like the footprints and coprolites of extinct creatures. After the death of the last of the Sweetloves, the manor house had changed hands with alarming rapidity. There were constant fears in Pagford that some developer would buy and mutilate the beloved landmark. Then, in the 1950s, a man called Aubrey Fawley purchased the place. Fawley was soon known to be possessed of substantial private wealth, which he supplemented in mysterious ways in the City. He had four children, and a desire to settle permanently. Pagford's approval was raised to still giddier heights by the swiftly circulated intelligence that Fawley was descended, through a collateral line, from the Sweetloves. He was clearly half a local already, a man whose natural allegiance would be to Pagford and not to Yarvil. Old Pagford believed that the advent of Aubrey Fawley meant the return of a charmed era. He would be a fairy godfather to the town, like his ancestors before him, showering grace and glamour over their cobbled streets. Howard Mollison could still remember his mother bursting into their tiny kitchen in Hope Street with the news that Aubrey had been invited to judge the local flower show. Her runner beans had taken the vegetable prize three years in a row, and she yearned to accept the silver-plated rose bowl from a man who was already, to her, a figure of old-world romance. III But then, so local legend told, came the sudden darkness that attends the appearance of the wicked fairy. Even as Pagford was rejoicing that Sweetlove House had fallen into such safe hands, Yarvil was busily constructing a swath of council houses to its south. The new streets, Pagford learned with unease, were consuming some of the land that lay between the city and the town. Everybody knew that there had been an increasing demand for cheap housing since the war, but the little town, momentarily distracted by Aubrey Fawley's arrival, began to buzz with mistrust of Yarvil's intentions. The natural barriers of river and hill that had once been guarantors of Pagford's sovereignty seemed diminished by the speed with which the red-brick houses multiplied. Yarvil filled every inch of the land at its disposal, and stopped at the northern border of Pagford Parish. The town sighed with a relief that was soon revealed to be premature. The Cantermill Estate was immediately judged insufficient to meet the population's needs, and the city cast about for more land to colonize. It was then that Aubrey Fawley (still more myth than man to the people of Pagford) made the decision that triggered a festering sixty-year grudge. Having no use for the few scrubby fields that lay beyond the new development, he sold the land to Yarvil Council for a good price, and used the cash to restore the warped panelling in the hall of Sweetlove House. Pagford's fury was unconfined. The Sweetlove fields had been an important part of its buttress against the encroaching city; now the ancient border of the parish was to be compromised by an overspill of needy Yarvilians. Rowdy town hall meetings, seething letters to the newspaper and Yarvil Council, personal remonstrance with those in charge – nothing succeeded in reversing the tide. The council houses began to advance again, but with one difference. In the brief hiatus following completion of the first estate, the council had realized that it could build more cheaply. The fresh eruption was not of red brick but of concrete in steel frames. This second estate was known locally as the Fields, after the land on which it had been built, and was marked as distinct from the Cantermill Estate by its inferior materials and design. It was in one of the Fields' concrete and steel houses, already cracking and warping by the late 1960s, that Barry Fairbrother was born. IV In spite of Yarvil Council's bland assurances that maintenance of the new estate would be its own responsibility, Pagford – as the furious townsfolk had predicted from the first – was soon landed with new bills. While the provision of most services to the Fields, and the upkeep of its houses, fell to Yarvil Council, there remained matters that the city, in its lofty way, delegated to the parish: the maintenance of public footpaths, of lighting and public seating, of bus shelters and common land. Graffiti blossomed on the bridges spanning the Pagford to Yarvil road; Fields bus shelters were vandalized; Fields teenagers strewed the play park with beer bottles and threw rocks at the street lamps. A local footpath, much favoured by tourists and ramblers, became a popular spot for Fields youths to congregate, ‘and worse', as Howard Mollison's mother put it darkly. It fell to Pagford Parish Council to clean, to repair and to replace, and the funds dispersed by Yarvil were felt from the first to be inadequate for the time and expense required. No part of Pagford's unwanted burden caused more fury or bitterness than the fact that Fields children now fell inside the catchment area of St Thomas's Church of England Primary School. Young Fielders had the right to don the coveted blue and white uniform, to play in the yard beside the foundation stone laid by Lady Charlotte Sweetlove and to deafen the tiny classrooms with their strident Yarvil accents. It swiftly became common lore in Pagford that houses in the Fields had become the prize and goal of every benefit-supported Yarvil family with school-age children; that there was a great ongoing scramble across the boundary line from the Cantermill Estate, much as Mexicans streamed into Texas. Their beautiful St Thomas's – a magnet for professional commuters to Yarvil, who were attracted by the tiny classes, the rolltop desks, the aged stone building and the lush green playing field – would be overrun and swamped by the offspring of scroungers, addicts and mothers whose children had all been fathered by different men. This nightmarish scenario had never been fully realized, because while there were undoubtedly advantages to St Thomas's there were also drawbacks: the need to buy the uniform, or else to fill in all the forms required to qualify for assistance for the same; the necessity of attaining bus passes, and of getting up earlier to ensure that the children arrived at school on time. Some households in the Fields found these onerous obstacles, and their children were absorbed instead by the large plain-clothes primary school that had been built to serve the Cantermill Estate. Most of the Fields pupils who came to St Thomas's blended in well with their peers in Pagford; some, indeed, were admitted to be perfectly nice children. Thus Barry Fairbrother had moved up through the school, a popular and clever class clown, only occasionally noticing that the smile of a Pagford parent stiffened when he mentioned the place where he lived. Nevertheless, St Thomas's was sometimes forced to take in a Fields pupil of undeniably disruptive nature. Krystal Weedon had been living with her great-grandmother in Hope Street when the time came for her to start school, so that there was really no way of stopping her coming, even though, when she moved back to the Fields with her mother at the age of eight, there were high hopes locally that she would leave St Thomas's for good. Krystal's slow passage up the school had resembled the passage of a goat through the body of a boa constrictor, being highly visible and uncomfortable for both parties concerned. Not that Krystal was always in class: for much of her career at St Thomas's she had been taught one-on-one by a special teacher. By a malign stroke of fate, Krystal had been in the same class as Howard and Shirley's eldest granddaughter, Lexie. Krystal had once hit Lexie Mollison so hard in the face that she had knocked out two of her teeth. That they had already been wobbly was not felt, by Lexie's parents and grandparents, to be much of an extenuation. It was the conviction that whole classes of Krystals would be waiting for their daughters at Winterdown Comprehensive that finally decided Miles and Samantha Mollison on removing both their daughters to St Anne's, the private girls' school in Yarvil, where they had become weekly boarders. The fact that his granddaughters had been driven out of their rightful places by Krystal Weedon, swiftly became one of Howard's favourite conversational examples of the estate's nefarious influence on Pagford life. V The first effusion of Pagford's outrage had annealed into a quieter, but no less powerful, sense of grievance. The Fields polluted and corrupted a place of peace and beauty, and the smouldering townsfolk remained determined to cut the estate adrift. Yet boundary reviews had come and gone, and reforms in local government had swept the area without effecting any change: the Fields remained part of Pagford. Newcomers to the town learned quickly that abhorrence of the estate was a necessary passport to the goodwill of that hard core of Pagfordians who ran everything. But now, at long last – over sixty years after Old Aubrey Fawley had handed Yarvil that fatal parcel of land – after decades of patient work, of strategizing and petitioning, of collating information and haranguing sub-committees – the anti-Fielders of Pagford found themselves, at last, on the trembling threshold of victory. The recession was forcing local authorities to streamline, cut and reorganize. There were those on the higher body of Yarvil District Council who foresaw an advantage to their electoral fortunes if the crumbling little estate, likely to fare poorly under the austerity measures imposed by the national government, were to be scooped up, and its disgruntled inhabitants joined to their own voters. Pagford had its own representative in Yarvil: District Councillor Aubrey Fawley. This was not the man who had enabled the construction of the Fields, but his son, ‘Young Aubrey', who had inherited Sweetlove House and who worked through the week as a merchant banker in London. There was a whiff of penance in Aubrey's involvement in local affairs, a sense that he ought to make right the wrong that his father had so carelessly done to the little town. He and his wife Julia donated and gave out prizes at the agricultural show, sat on any number of local committees, and threw an annual Christmas party to which invitations were much coveted. It was Howard's pride and delight to think that he and Aubrey were such close allies in the continuing quest to reassign the Fields to Yarvil, because Aubrey moved in a higher sphere of commerce that commanded Howard's fascinated respect. Every evening, after the delicatessen closed, Howard removed the tray of his old-fashioned till, and counted up coins and dirty notes before placing them in a safe. Aubrey, on the other hand, never touched money during his office hours, and yet he caused it to move in unimaginable quantities across continents. He managed it and multiplied it and, when the portents were less propitious, he watched magisterially as it vanished. To Howard, Aubrey had a mystique that not even a worldwide financial crash could dent; the delicatessen-owner was impatient of anyone who blamed the likes of Aubrey for the mess in which the country found itself. Nobody had complained when things were going well, was Howard's oft-repeated view, and he accorded Aubrey the respec t due to a general injured in an unpopular war. Meanwhile, as a district councillor, Aubrey was privy to all kinds of interesting statistics, and in a position to share a good deal of information with Howard about Pagford's troublesome satellite. The two men knew exactly how much of the district's resources were poured, without return or apparent improvement, into the Fields' dilapidated streets; that nobody owned their own house in the Fields (whereas the red-brick houses of the Cantermill Estate were almost all in private hands these days; they had been prettified almost beyond recognition, with window-boxes and porches and neat front lawns); that nearly two-thirds of Fields-dwellers lived entirely off the state; and that a sizeable proportion passed through the doors of the Bellchapel Addiction Clinic. VI Howard carried the mental image of the Fields with him always, like a memory of a nightmare: boarded windows daubed with obscenities; smoking teenagers loitering in the perennially defaced bus shelters; satellite dishes everywhere, turned to the skies like the denuded ovules of grim metal flowers. He often asked rhetorically why they could not have organized and made the place over – what was stopping the residents from pooling their meagre resources and buying a lawnmower between the lot of them? But it never happened: the Fields waited for the councils, District and Parish, to clean, to repair, to maintain; to give and give and give again. Howard would then recall the Hope Street of his boyhood, with its tiny back gardens, each hardly more than tablecloth-sized squares of earth, but most, including his mother's, bristling with runner beans and potatoes. There was nothing, as far as Howard could see, to stop the Fielders growing fresh vegetables; nothing to stop them disciplining their sinister, hooded, spray-painting offspring; nothing to stop them pulling themselves together as a community and tackling the dirt and the shabbiness; nothing to stop them cleaning themselves up and taking jobs; nothing at all. So Howard was forced to draw the conclusion that they were choosing, of their own free will, to live the way they lived, and that the estate's air of slightly threatening degradation was nothing more than a physical manifestation of ignorance and indolence. Pagford, by contrast, shone with a kind of moral radiance in Howard's mind, as though the collective soul of the community was made manifest in its cobbled streets, its hills, its picturesque houses. To Howard, his birthplace was much more than a collection of old buildings, and a fast-flowing, tree-fringed river, the majestic silhouette of the abbey above or the hanging baskets in the Square. For him, the town was an ideal, a way of being; a micro-civilization that stood firmly against a national decline. ‘I'm a Pagford man,' he would tell summertime tourists, ‘born and bred.' In so saying, he was giving himself a profound compliment disguised as a commonplace. He had been born in Pagford and he would die there, and he had never dreamed of leaving, nor itched for more change of scene than could be had from watching the seasons transform the surrounding woods and river; from watching the Square blossom in spring or sparkle at Christmas. Barry Fairbrother had known all this; indeed, he had said it. He had laughed right across the table in the church hall, laughed right in Howard's face. ‘You know, Howard, you are Pagford to me.' And Howard, not discomposed in the slightest (for he had always met Barry joke for joke), had said, ‘I'll take that as a great compliment, Barry, however it was intended.' He could afford to laugh. The one remaining ambition of Howard's life was within touching distance: the return of the Fields to Yarvil seemed imminent and certain. Then, two days before Barry Fairbrother had dropped dead in a car park, Howard had learned from an unimpeachable source that his opponent had broken all known rules of engagement, and had gone to the local paper with a story about the blessing it had been for Krystal Weedon to be educated at St Thomas's. The idea of Krystal Weedon being paraded in front of the reading public as an example of the successful integration of the Fields and Pagford might (so Howard said) have been funny, had it not been so serious. Doubtless Fairbrother would have coached the girl, and the truth about her foul mouth, the endlessly interrupted classes, the other children in tears, the constant removals and reintegrations, would be lost in lies. Howard trusted the good sense of his fellow townsfolk, but he feared journalistic spin and the interference of ignorant do-gooders. His objection was both principled and personal: he had not yet forgotten how his granddaughter had sobbed in his arms, with bloody sockets where her teeth had been, while he tried to soothe her with a promise of triple prizes from the tooth fairy.

The life cycle of a star

In this physics coursework, I have been asked to carry out research of my selection and to develop it. I have selected to research the life cycle of a star, and I would conduct this by gathering the necessary information in a form of a report which explains this in detail. I have chosen to explore this particular topic firstly because I am extremely fascinated in space and the universe and secondly because I do not know much about the life cycle of a star and I deem this will help extend my knowledge. Firstly when carrying out this research before describing the life cycle of a star I need to be familiar of what a star is, and how it is formed What is a star, and how does it form? Stars are basically huge balls of hydrogen gas. Hydrogen is by far the most common element in the Universe, and stars form in clusters when large clouds of hydrogen, which naturally forms a hydrogen ‘molecule' (H+H=H2) with another atom, collapse. The hydrogen clouds collapses very slowly, although they can be speeded up by the effects of a passing star, or the shockwave from a distant supernova explosion. As the cloud collapses, it speeds up its rotation, and pulls more material into the centre, where a denser ball of gas, the ‘proto-star' forms. The proto-star collapses under its own weight, and the collisions between hydrogen molecules inside it generate heat. Eventually the star becomes hot enough for the hydrogen molecules to split apart, and form atoms of hydrogen. The star keeps on collapsing under its own weight, and getting even hotter in the core, until finally it is hot enough there (roughly 10 million degrees) for it to start generating energy, by nuclear fusion – combining hydrogen atoms to form a heavier element, helium. Energy is released from the core, and pushes its way out through the rest of the star, creating an outward pressure which stops the star's collapse. When the energy emerges from the star, it is in the form of light, and the star has begun to shine. A Star is formed from a cloud of gas, mostly hydrogen, and the dust that is initially spread over a huge volume, but which is pulled together by its own collective gravity. This gravitational collapse of the cloud creates a body of large density, and the loss of gravitational potential energy in the process is very large indeed. The result is that the original particles acquire high kinetic energy, so that the collisions between them are very violent. Atoms lose their electrons. Not only has that, collisions taken place in which electrical repulsion of nuclei is no longer strong enough to keep them apart. They can become close enough together for the strong nuclear force to take effect, so that they merge. Fusion takes place, with hydrogen as the principal key material. This begins the process of conversion of mass to energy, and much of the released energy takes the form of photons which begins to stream from the new star. Every star then exists in a state of slowly evolving stability. On the one hand there is the trend for the material to continue to collapse under gravity. On the other hand there is a tendency for the violent thermal activity and the emission of radiation resulting from fusion to blow the material apart. The more bigger star in general, the greater is the gravitational pressure and so the higher rate of energy is released by fusion, therefore bigger stars use up their supply of fusing nuclei more quickly than do smaller stars, such that bigger stars have shorter lives. The enormous luminous energy of the stars comes from nuclear fusion processes in their centres. Depending upon the age and mass of a star, the energy may come from proton fusion, helium fusion, or the carbon cycle. For brief periods near the end of the luminous lifetime of stars, heavier elements up to iron may fuse, but since iron is at the peak of the binding energy curve, the fusion of elements more massive than iron would soak up energy rather than deliver it. This links to the below graph: Fusion in stars makes energy available to create radiation, consuming mass at an amazing rate. The sun, for example loses a mass of 4.5 million tonnes every second. Also, heavier nuclei are formed from smaller ones, so that the compression of a star changes. Concluding this, as the star dies the material dependant on its size is scattered in space. The Hertzsprung – Russell Diagram This simple graph shows ways in which to classify stars. Temperature is plotted on the x-axis. This is related to the colour as cooler stars are redder, hotter stars are bluer. Relative luminosity is plotted on the y-axis. Because of the very wide range of temperatures and stellar luminosities, logarithmic scales are used. The location of an individual star on such a graph lets us establish a loose system of classification. This graph aids us to find out what star has what temperature so we can easily classify it using the relative luminosity and temperature. Here is a diagram of the graph which shows the stars in their classified points showing their rough temperature and luminosity. So how do the changes in the stars take place? Very massive stars experience several stages in their cores. o First hydrogen fuses into helium then helium to carbon creating larger nuclei. Such large stars in later life can have shells or layers with heavier nuclei towards their centres. It is not only the life expectancy of a star that depends on its mass, but also the way which it dies. o Older stars have outer layers in which hydrogen is the fuel for fusion, while the inner layers helium is the fuel, and for massive stars there may be further layers beneath. Most stars, including the sun become red giants after the end of their equilibrium phase. o This process is started by cooling in the inner core, resulting in reduced thermal pressure and radiation pressure and so causing gravitational collapse of the hydrogen shell. But the gravitational collapse provides energy for heating the shell, and so the rate of fusion in the shell increases. This makes the shell expand enormously. o The outermost surface of the star becomes cooler, and its light becomes redder, but the larger surface area means that the stars luminosity increases. o Meanwhile the gravitational collapse affects the core as well, and ultimately the process of fusion of helium in the core cause the outer shell to expand further and thin leaving the hot extremely dense core as a white dwarf. o Slowly this cools and becomes a black dwarf. o For the stars that are several times bigger then the sun, death may be even more dramatic. A core of carbon is created by fusion of helium, and once this core is sufficiently compressed then fusion of the carbon itself takes place. The rapid release of energy makes the star briefly as bright as a galaxy, as bright as 10 billion stars. o The star explodes into a supernova and its material spreads back into the space around. In even larger stars, fusion of carbon can continue more steadily, producing still larger nuclides and ultimately creating iron nuclei. The iron nuclei also experience fusion, but these are different as they are energy consuming meaning they keep it in. The central core of the star collapses under gravity. This increases temperature but cannot now greatly increase the rate of fusion, so collapse continues. Outer layers also collapse around the core, compressing it further. It becomes denser then an atomic nucleus, protons and electrons join together to create neutrons. o Meanwhile, the collapse of the outer layers heats these, increasing the rate of fusion so that suddenly the star explodes as a supernova. This spreads the material of these layers into space, leaving a small hot body behind a neutron star. o Furthermore if this supernova is big enough, its gravity continues to pull the matter towards a single point with a huge gravitational field where not even light can escape from is known as the black hole. Star pictures obtained from Internet http://www.enchantedlearning.com/subjects/astronomy Here is an illustration of a star life cycle followed by the theory How long a star lives for and how it dies†¦ How long a star lives and how it dies, depends entirely on how massive it is when it begins. A small star can sustain basic nuclear fusion for billions of years. Our sun, for example, probably can sustain reactions for some 10 billion years. Really big stars have to conduct nuclear fusion at an enormous rate to keep in hydrostatic equilibrium and quickly falter, sometimes as fast as 40,000 years. If the star is about the same mass as the Sun, it will turn into a white dwarf star. If it is somewhat more massive, it may undergo a supernova explosion and leave behind a neutron star. But if the collapsing core of the star is very great at least three times the mass of the Sun nothing can stop the collapse. The star implodes to form an infinite gravitational warp in space, a hole. This is exemplified in a very simple diagram highlighting the consequence of each mass of the stars and what they will revolve into. Normal stars such as the Sun are hot balls of gas millions of kilometres in diameter. The visible surfaces of stars are called the photospheres, and have temperatures ranging from a few thousand to a few tens of thousand degrees Celsius. The outermost layer of a star's atmosphere is called the â€Å"corona†, which means â€Å"crown†. The gas in the coronas of stars has been heated to temperatures of millions of degrees Celsius. Most radiation emitted by stellar coronas is in X-rays because of its high temperature. Studies of X-ray emission from the Sun and other stars are therefore primarily studies of the coronas of these stars. Although the X-radiation from the coronas accounts for only a fraction of a percent of the total energy radiated by the stars, stellar coronas provide us with a cosmic laboratory for finding out how hot gases are produced in nature and how magnetic fields interact with hot gases to produce flares, spectacular explosions that release as much energy as a million hydrogen bombs The Orion Trapezium as observed. The colours represent energy; where blue and white indicate very high energies and therefore extreme temperatures. The size of the X-ray source in the image also reflects its brightness, i.e. more bright sources appear larger in size. The Life Cycle of a star: In Large Stars In hot massive stars, the energy flowing out from the centre of the star is so intense that the outer layers are literally being blown away. Unlike a nova, these stars do not shed their outer layers explosively, but in a strong, steady stellar wind. Shock waves in this wind produce X-rays; from the intensity and distribution with energy of these X-rays, astronomers can estimate the temperature, velocity and density of this wind. Medium sized Stars In medium-sized stars, such as the Sun, the outer layers consist of a rolling, boiling disorder called convection. A familiar example of convection is a sea-breeze. The Sun warms the land more quickly than the water and the warm air rises and cools as it expands. It then sinks and pushes the cool air off the ocean inland to replace the air that has risen, producing a sea-breeze. In the same way, hot gas rises from the central regions of the Sun, cools at the surface and descends again. From Red Giant To supernova Once stars that are 5 times or more massive than our Sun reach the red giant phase, their core temperature increases as carbon atoms are formed from the fusion of helium atoms. Gravity continues to pull carbon atoms together as the temperature increases and additional fusion processes proceed, forming oxygen, nitrogen, and eventually iron. As the shock encounters material in the star's outer layers, the material is heated, fusing to form new elements and radioactive isotopes. While many of the more common elements are made through nuclear fusion in the cores of stars, it takes the unstable conditions of the supernova explosion to form many of the heavier elements. The shock wave propels this material out into space. The material that is exploded away from the star is now known as a supernova remnant. The White Dwarf A star experiences an energy crisis and its core collapses when the star's basic, non-renewable energy source, hydrogen which is used up. A shell of hydrogen on the edge of the collapsed core will be compressed and heated. The nuclear fusion of the hydrogen in the shell will produce a new surge of power that will cause the outer layers of the star to expand until it has a diameter a hundred times its present value. This is called the ‘red giant' phase of a star's existence. There are other possible conditions that allow astronomers to observe X-rays from a white dwarf. These opportunities occur when a white dwarf is capturing matter from a nearby companion star. As captured matter falls onto the surface of the white dwarf, it accelerates and gains energy. This energy goes into heating gas on or just above the surface of the white dwarf to temperatures of several million degrees. The hot gas glows brightly in X-rays. A careful analysis of this process can reveal the mass of the white dwarf, its rate of rotation and the rate at which matter is falling onto it. In some cases, the matter that gathers on the surface can become so hot and dense that nuclear reactions occur. When that happens, the white dwarf suddenly becomes 10,000 times brighter as the explosive outer layers are blown away in what is called a nova outburst. After a month or so, the excitement is over and the cycle begins anew. The Supernova Every 50 years or so, a massive star in our galaxy blows itself apart in a supernova explosion. Supernovas are one of the most violent events in the universe, and the force of the explosion generates a blinding flash of radiation, as well as shock waves analogous to sonic booms. There are two types of supernovas: o Type II, where a massive star explodes o Type I, where a white dwarf collapses because it has pulled too much material from a nearby companion star onto itself. The general picture for a Type II supernova is when the nuclear power source at the centre or core of a star is exhausted, the core collapses. In less than a second, a neutron star (or black hole, if the star is extremely massive) is formed. When matter crashes down on the neutron star, temperatures rise to billions of degrees Celsius. Within hours, a disastrous explosion occurs, and all but the central neutron star is blown away at speeds in excess of 50 million kilometres per hour. A thermonuclear shock wave races through the now expanding stellar debris, fusing lighter elements into heavier ones and producing a brilliant visual outburst that can be as intense as the light of ten billion Suns. The matter thrown off by the explosion flows through the surrounding gas producing shock waves that create a shell of multimillion degrees gas and high energy particles called a supernova remnant. The supernova remnant will produce intense radio and X-radiation for thousands of years. In several young supernova remnants the rapidly rotating neutron star at the centre of the explosion gives off pulsed radiation at X-ray and other wavelengths, and creates a magnetized bubble of high-energy particles whose radiation can dominate the appearance of the remnant for a thousand years or more. Eventually, after rumbling across several thousand light years, the supernova remnant will disperse. The Neutron Stars The nucleus contains more than 99.9 percent of the mass of an atom, yet it has a diameter of only 1/100,000 that of the electron cloud. The electrons themselves take up little space, but the pattern of their orbit defines the size of the atom, which is therefore 99.9% open space. What we perceive as solid when we bump against a rock is really a disorder of electrons moving through empty space so fast that we can't see or feel the emptiness. Such extreme forces occur in nature when the central part of a massive star collapses to form a neutron star. The atoms are crushed completely, and the electrons are jammed inside the protons to form a star composed almost entirely of neutrons. The result is a tiny star that is like a gigantic nucleus and has no empty space. Neutron stars are strange and fascinating objects. They represent an extreme state of matter that physicists are eager to know more about. The intense gravitational field would pull your spacecraft to pieces before it reached the surface. The magnetic fields around neutron stars are also extremely strong. Magnetic forces squeeze the atoms into the shape of cigars. Even if a spacecraft carefully stayed a few thousand miles above the surface neutron star so as to avoid the problems of intense gravitational and magnetic fields, you would still face another potentially fatal hazard. If the neutron star is rotating rapidly, as most young neutron stars are, the strong magnetic fields combined with rapid rotation create an amazing generator that can produce electric potential differences of trillions of volts. Such voltages, which are 30 million times greater than those of lightning bolts, create deadly blizzards of high-energy particles. If a neutron star is in a close orbit around a normal companion star, it can capture matter flowing away from that star. This captured matter will form a disk around the neutron star from which it will spiral down and fall, or accrete, onto the neutron star. The in falling matter will gain an enormous amount of energy as it accelerates. Much of this energy will be radiated away at X-ray energies. The magnetic field of the neutron star can funnel the matter toward the magnetic poles, so that the energy release is concentrated in a column, or spot of hot matter. As the neutron star rotates, the hot region moves into and out of view and produces X-ray pulses. Black Holes When a star runs out of nuclear fuel, it will collapse. If the core, or central region, of the star has a mass that is greater than three Suns, no known nuclear forces can prevent the core from forming a deep gravitational damage in space called a black hole. A black hole does not have a surface in the usual sense of the word. There is simply a region, or boundary, in space around a black hole beyond which we cannot see. This boundary is called the event horizon. Anything that passes beyond the event horizon is doomed to be crushed as it descends ever deeper into the gravitational well of the black hole. No visible light, nor X-rays, nor any other form of electromagnetic radiation, or any particle, no matter how energetic, can escape. The radius of the event horizon (proportional to the mass) is very small, only 30 kilometres for a non-spinning black hole with the mass of 10 Suns.