Potential of Deregulation of the Electricity Sector in the State of Essay

Potential of Deregulation of the Electricity Sector in the State of Qatar - Essay Example The highest number of vacancies in employment sector is related to Oil and gas industry. Examples of posts are Rotating Equipment Engineer, Terminal Supervisor, and Mobile Concrete Pump Operator and many others. Least job opportunities are available in retailing services and IT related jobs (Chaddock, 2008). Estimated percentage of literacy in 1985 was 74%. The percentage increased to 81% in 2000. Centre for eliminate literacy rate was formed in 1954 in Qatar. There were seven schools in 1956, which could cater to the requirement of 614 students. By paying utmost attention to this sector, literacy has increased dramatically. Elementary schooling is of four year period in Qatar. Illiterate students were educated under this program and were granted certificates. Incentive allowance is given to such students, which was QR150 per month (Guides, 2010). The estimated population in 1998 was 579,000. 20% among this population was Qatari. The remaining population is of foreign workers. The po pulation living in urban areas is 91.4 % and the remaining 9.6% lives in rural areas. The total population is an imbalance. The number of males is greater than females. Basic reason is that the foreign workers are not living with their families, as they come alone. The type of visa allotted to foreign workers is work visa, which are temporary visas. Most of the foreign workers come from Pakistan and India (Chaddock, 2008). Production The production of electricity in 2008 was approximately 4263 Megawatts (MW). It is assumed that in 2011 it will double and increase up to 8707 MW. These values prove the development of electricity sector in Qatar. The number of substations of high voltage has increased to 139 in 2008. By the turn of century there were 87 substations in... This paper approves that the expansion of power stations is done by placing complex power equipment in different substations. This activity is performed by the employees of KAHRAMAA. They are making the electric power system highly developed and dependable as well. Many international companies are interested in the project launch of Qatar Electricity Transmission Networks. There basic goal is to expand their transmitted network. The projects of KAHRAMAA are considered as the largest projects in the world. Phase VIII was the largest project of network expansion. The contracts of this project are worth US$ 3.5 billion. Phase IX is the next upcoming network project. KAHRAMAA has also decided to expand the network of Phase VIII. Their technical department is responsible for tracking deadlines. Basic target of the researcher is to research and find the best suitable structure for electricity production and management in Qatar. It will not be easy to regulate electricity sector in Qatar. This report makes a conclusion that while collecting the data, it will be ensured that no confidential/classified information offered by the companies is misused. Official permission from electricity authorities will be taken in writing to use their data. The data will be protected. Names of the participants in my primary data collection interviews/survey will not be displaced in any situation. The company data and any personal information collected during this research will be safe guarded carefully to ensure no information theft or misuse of information.

Health Problems among Teens and Young Adults Assignment

Health Problems among Teens and Young Adults - Assignment Example Consequently, family support is very vital as it allows the concerned persons to make appropriate decisions. Teenagers and young adults are strongly accustomed to social associations with their peers. In case their peers cannot make healthy decisions or indulge in activities that are against the law like drug abuse, they will also tend to develop risk-taking behaviors. Specific attention is directed to the wellbeing of teenagers brought up in single-parent families. It has been discovered that such children do not fare well compared to those coming from families with both parents (Amato &Fowler, 2002). Researches have always indicated that such teenagers and young adults tend to experience health or academic problems. These might change their mindset and make them think of unhealthy decisions like taking alcohol or drugs to reduce the levels of stress. Teenagers and young adults form and join groups for different reasons. For instance, some may decide to join the groups because they want to have a sense of family. They develop feelings that they are not receiving sufficient consideration at home. Moreover, children raised by single mothers might also search for a father figure from the groups (Sanchez-Jankowski, 2003). Negative behavior increases when the teens try to copy their peers in the group. For instance, when most of the members in the group are smokers, one would also be tempted to smoke in order to act in a similar manner. With time, this leads to addiction. Teenagers tend to get involved in gang violence, drug trade, drug abuse, and other unlawful activities due to the social and economic status of the marginal population in United States (Vigil, 2003). This becomes dangerous to the health. For instance, drug abuse or smoking always comes with serious health problems. Such teenagers will not afford and access quality health care. Other issues affecting minority groups that

Free Topic Essay Example | Topics and Well Written Essays - 500 words

Free Topic - Essay Example The inner thoughts of the protagonist, Mrs. Mallard, form the leitmotif of story. News of a railroad accident in which Mr. Brently Mallard had supposedly died and what happens in the span of an hour afterwards form the plot. Chopin focuses on Mrs. Mallard’s unique psyche through the narrative technique of interior monologue. Her sister Josephine and Mr. Mallard’s friend Richards break the news of Mr. Mallard’s death as gently as possible. The readers are also led to believe that the news could have a devastating effect on her. She is described as responding instantaneously to the news by weeping at once, â€Å"with wild abandonment†. Contrary to many women who would have remained in a paralyzed inability to accept the news and its significance, she did let her emotions flow on a stretch. However, she went alone to her room once the storm of grief had subsided. No one was allowed to follow her there. The time she spent alone in her room happens to be the tu rning point in the story. She continued sobbing absent mindedly for a while, in a stupor-like condition. But she kept on staring outside through the open window, supposedly in a â€Å"suspension of intelligent thought†. She realized something coming to her, but was unable to realize it fully. Her demeanor changed dramatically as she realized that it is freedom that is awaiting her. She got very excited at this prospect. Even as she reflected on the necessity to weep once her husband’s dead body arrives, the state of excitement refuses to fade away from her essence of being. She thought of love as something that existed only occasionally in her relationship with her husband. Love seemed like an unsolved mystery to her while she was swept away by a possession of self-assertion. She perceives that she is free altogether now, body and soul. The twist in the end reveals that the information regarding the death of Mr. Mallard was baseless, and he turns up

Survey Design Assignment Example | Topics and Well Written Essays - 500 words

Survey Design - Assignment Example Please send back the filled questionnaire within two weeks of receipt. Thank you in advance. The target population for the study is employees and employers in the Department of Veterans Affairs who agree to participate in the study. The reason for the choice of the population are that the employers and employees are mostly affected by workplace conflicts and the ability of resolving workplace conflicts in an amicable manner is beneficial for the employers and employees for work efficiency and effectiveness The chosen sample will consist of 100 employers and employees in the Department of Veteran Affairs. The sample is divided into two strata consisting of 50 employers and 50 employees to ensure the data is collected within the available time and the conclusions are all encompassing in terms of the views and opinions of the employees and the employers. The benefits of the sample chosen include accessibility and allows for the limited time for the research to be enough for completion of the study in a comprehensive manner1. The sampling process to be used is probability random sampling ensuring the selection of an appropriate sample for the study2. Stratified sampling will be in the division of the sample to two strata consisting of employers and employees. The benefits of using stratified random sampling include equitable distribution of the population under study, ensures equitable representation of the two strata in the sample chosen for use in the study, and accounting for the differences in the groups used for the study. The order of the questions has an effect on the responses through providing context for preceding questions. In a survey, having closed-ended questions before open-ended questions result in mentioning of concepts mentioned in earlier close-ended questions in filling open-ended questions. Open-ended questions have order effects in terms of contrast and assimilation effects in questionnaires where

Why was Ireland Partitioned Essay Example for Free

Why was Ireland Partitioned Essay In the late 19th century, Ulster became the most prosperous province in Ireland, with the only large-scale industrialization in the country. Its linen industry thrived and its products were imported throughout the world. In the latter part of the century, Belfast overtook Dublin as the largest city on the island. Belfast was particularly famous for its huge dockyards owned by Harland and Wolff1. After the famine there was a preponderance of Protestants in Ulster, with a much larger number of skilled workers than the Catholics. Ulster Unionism was and still is composed of two main elements; the protection and preservation of their religion and of the Ulster Economy. When the Home Rule party began introducing reforms such as the Land Act of 1870 Ulster Unionists began to feel threatened. They saw these reforms as the thin edge of a wedge which they feared might damage their interests2. Although there were vast gulfs of difference between them, they were able to unite remarkably well under the common banner of Unionism, a resolve which was strengthened with the start of land agitation in the North. They saw this as a direct attack on all they strove to protect3. In the 1885 elections, the Home Rule party won 17 of the 33 Ulster seats, a development which shocked many Unionism and Gladstone introduced his first Home Rule Bill. While Gladstone prepared an Irish policy, Lord Randolph Churchill prepared for his own visit to Ireland. In February, he wrote, I decided some time ago that if Gladstone went for Home Rule, the Orange card would be the one to play4. Ninety-three of Gladstones own Liberal MPs voted against the bill, and it was defeated. Disturbed at how close to success the Home Rulers had come, there was an influx of new members into the orange order. The Ulster loyalist anti repeal union was also established. They had a conditional loyalty to the crown which means they supported it as long as it did not interfere with their interests5. In 1886 the Belfast anti-Unionist riots damaged the Home Rule cause in the North. Also in that year Queens University became an independent University instead of affiliating to the other British Universities. In this way Unionists first began showing their feelings of self-reliance and autonomy6. The struggle for home rule continued, and Gladstone introduced a second bill in 1893, only to see it defeated in the House of Lords. The Parliament Act of 1911 reduced the peers veto on legislation to a delaying power. At this time there were three strands of Unionism the Ulster Unionism of Craig and the Unionist Council; the Irish Unionists with Edward Carson; and the British Unionism and Bonar Law. The Irish position changed when Carson, M.P., for Trinity College, was invited to lead Ulster Unionists in February, 19107. A meeting was held at Craigavon, Craigs home, to receive the new leader on 23 September, 1911; 100,000 people attended. The meeting marked the beginning of the campaign against the Home Rule Bill of Asquith which was to go before Parliament in 1912. This bill was rejected by the Lords, but became law in 19148. On the 28th September (Ulster Day) the Solemn League and covenant was signed by Unionist men only. This showed their opposition to Home Rule. Some to show their intent signed it with their own blood. In January 1913 the Ulster Volunteer force (UVF) was founded9. Men paraded and drilled with wooden weapons at first. At the end of April 35,000 rifles and 5 million rounds of ammunition were landed at Larne by the Unionists. No moves were made by the army or police to thwart them and this caused much anger amongst Nationalists. Herbert Asquiths policy of wait and see was not doing much for the situation and he failed to realise the intent of the Unionists. It was only in late 1913 that he began to take Ulster opposition seriously. The Curragh mutiny of July 1914 was a blow that showed his complete lack of power over Ulster10. The prospect of Ireland being partitioned began to be considered as a serious option around this time when Lloyd George suggested the temporary exclusion of parts of Ulster. Bonar Law stated that this should be permanent and Carson also refused to compromise. In July 1914 King George, recognising the looming crisis called the Buckingham Palace conference in an effort to make some progress. This conference was attended by Asquith, Lloyd George, Bonar Law, Carson, Craig, Redmond and Dillon11. At the conference Carson immediately stated that he would not consider anything other than partition. The question was the area for exclusion and the time for which it would be excluded. Redmond suggested that each county could be given a plebiscite whether to opt in or out of Home Rule12. Carson disagreed and said Ulster should vote as a block. This was unacceptable to Redmond. Neither side would concede the counties of Tyrone and Fermanagh. It was here that the conference broke down. The original intention of the Unionists was to defeat Home Rule for all Ireland. However, as time went on the idea of partition began to appeal more and more to them13. They began to see the safety from interference it would give them. What had began as a device for killing home rule had become an end in itself. The implementation of Home Rule had to be delayed for the duration of the Great War. A coalition government was set up and both Carson and Redmond were invited to become members. Redmond turned it down. This was to place him at a disadvantage that was to have severe consequences14. Carson accepted his place immediately. Urged by Redmond many nationalists signed up to fight in the war. The Unionists also fought. Both sides suffered terrible casualties notably at the Battle of the Somme. The war also brought with it the chance the Irish republicans had been waiting years for. The old saying Englands difficulty is Irelands opportunity rang clear as they started a Rising on Easter Monday 191615. As William Butler Yates later wrote about the event alls changed, changed utterly. All had changed. After the executions that followed 1916, the Irish people would no longer be happy with Home Rule. Overnight Redmond and the Home Rulers lost much of their power. Lloyd George organised talks in September 191816. He talked to Carson and Redmond separately. Carson was told he could have immediate permanent Home Rule for the six counties whilst he convinced Redmond it would only be a temporary measure until the war ended. The Irish Convention was an assembly called by Lloyd George which sat in Ireland from July 1917 until March 1918 to address the Irish Question. However it did not have much success in resolving the problems. By the end of the war John Redmond was dead, the Irish party was a spent force and Sinn Fein had come to power. Dail Eireann had been set up by the republicans as their own parliament to ignore Westminster. The British Government would have let Home Rule slide was it not for the fact it was still on the books. Walter Long was a British Unionist politician17. From October 1919 onwards, he was largely concerned with Irish affairs, serving as the chair of the cabinets Long Committee on Ireland. The purpose of this committee was to deal with the Irish question. He would only consider a settlement which was in the Unionists favor. In this capacity he saw them first reject the county by county option. Instead it was proposed that there would be two parliaments one in Dublin and one in Belfast. Both were directly answerable to Westminster. This move would give Unionists control over their own destiny18. The British governments official stance was in favor of ultimate unification. The Unionists were first offered nine counties. This was turned down as they feared nine was too big for them to retain full control over. Instead they demanded six counties. The government of Ireland bill was introduced on the 26th of February 192019. It caused much hostility in the border counties and rioting in Belfast between June and September. On 3rd May it came into effect, creating separate home rule governments for Southern Ireland and Northern Ireland, the latter he endowed with wider powers than its southern counterpart. Although in southern and western Ireland, this was soon superseded by the Anglo-Irish Treaty, which gave the new Irish Free State a much greater share of independence. The king opened the new parliament in Ulster in May 192120. In conclusion, this essay has examined the reasons behind the partition question in Ireland and had accessed the causes of this divide in detail. It is ironic that the Unionist people fought so hard and so long against Home Rule just to later adopt it for themselves. 1J. J. Lee, Ireland 1912-1985, pages 9-11 2 Alvin Jackson, Ireland 1798-1998, pages 145 3 D. G. Boyce, Nineteenth Century Ireland, pages 200-201 4 D. G. Boyce, Nineteenth Century Ireland, pages 194-195 5 Pauric Travers, Settlements and Divisions, 116-117 6 Paul Bew, Ideology and the Irish Question: Ulster Unionism and Irish Nationalism 1912-1916 pages 8-9 7 D. G. Boyce, Nineteenth Century Ireland, pages 186-187 8 Michael Laffan, The Partition of Ireland, 1911-1925 9 Pauric Travers, Settlements and Divisions, pages 126-128 10 Alvin Jackson, Ireland 1798-1998, pages 151-153 11 J. J. Lee, Ireland 1912-1985, pages 17-20 12 D. G. Boyce, Nineteenth Century Ireland, pages 200 13 Alvin Jackson, Ireland 1798-1998, pages 156 14 J. J. Lee, Ireland 1912-1985, pages 13-15 15 Pauric Travers, Settlements and Divisions, pages 139-140 16 Pauric Travers, Settlements and Divisions, pages 145 17 J. J. Lee, Ireland 1912-1985, pages 19-20 18 Paul Bew, Ideology and the Irish Question: Ulster Unionism and Irish Nationalism 1912-1916 pages 17 19 Paul Bew, Ideology and the Irish Question: Ulster Unionism and Irish Nationalism 1912-1916 pages 118-119 20 J. J. Lee, Ireland 1912-1985, pages 24-25

Protective Effects Of Fluoride Toothpastes Health And Social Care Essay

Protective Effects Of Fluoride Toothpastes Health And Social Care Essay The main aim of this report is to discuss the evidence for the protective effects of fluoride toothpastes and varnishes. In addition, I will discuss their application and mode of action. To begin with, I will give a brief history of fluoride and how it fits into the reversal of tooth decay. I will discuss fluoride varnishes namely Duraphat, Fluor Protector and Duraflor and their effect on the DMF Index and their roles in school based prevention programmes. There are other varnishes such as Lawefluor and Bifluorid but these are less commonly used and therefore, I will not be discussing them. After discussing fluoride varnishes, I will consider fluoride toothpastes. I will give a description on the composition of a typical toothpaste and the effect of fluoride toothpastes on the DMF Index. In addition, I will discuss the effects of high fluoride concentration toothpastes. Finally, I will compare both toothpastes and varnishes. Contents Pages Summary Contents Introduction Deposition of fluoride in enamel What is tooth decay? Fluoride: Mode of Action Who is at risk of decay? Optimum fluoride concentration required for remineralisation DMF Index Main Section What are fluoride varnishes? Effect on DMFT/S The effect of fluoride varnishes according to different caries risk School based prevention programmes The use of fluoride varnish in inhibiting secondary carious lesions What are fluoride toothpastes? Use of fluoride toothpastes in clinical trials High Fluoride toothpastes The use of fluoride toothpastes in advanced enamel lesions Comparison of Toothpastes and Varnishes Conclusion Acknowledgements Word Count References Introduction I have decided to carry out this report on fluoride as I realise the importance of its role in the prevention of tooth decay (dental caries). Fluoride is a negative ion of the element fluorine and is found naturally in water, foods, soil, and minerals such as fluorite (calcium fluoride) and fluorapatite. Fluoride can also be synthesised in laboratories where it can be added to oral hygiene products and to water. Fluoride utilisation has occurred in two phases: before water fluoridation in the 1950s and after the widespread use of fluoridated dentifrices in the 1980s (Cury, Tenuta 2008) when less than 10% of toothpastes contained fluoride compared with 96% at present. Fluoride is most effective post-eruptively (Oganessian, Lencova Broukal 2007) where the effects are generally topical and therefore, it is important for a constant fluoride concentration to be maintained in the oral environment. Topically applied fluoride provides high concentrations of fluoride to surfaces of the denti tion. This provides a local protective effect and prevents ingestion of large amounts of fluoride. (Marinho et al. 2004) Deposition of fluoride in enamel During apatite crystal formation, low concentrations of fluoride are incorporated into the tooth structure. This leads to supersaturation with respect to fluoridated hydroxyapatite: {{66 ten Cate,J.M. 2008) Ca10(PO4)6(OH)2+ F-= Ca10(PO4)6(F)2 + 2OH- (Fluorapatite) After calcification is complete and prior to eruption, additional fluoride is taken up by the surface enamel. After eruption, the enamel continues to take up fluoride from its oral environment leading to its profound topical effects (Kidd 2005). What is tooth decay? It is important to consider the causes of tooth decay and how fluoride can be used to reverse the carious process. Dental Caries is a multifactorial disease caused by the action of acidogenic and aciduric bacteria (Streptococcus Mutans and Lactobacilli ({{32 Featherstone,J.D. 2008}}) on fermentable carbohydrates such as sucrose. Salivary glycoproteins form a pellicle on the tooth to which these bacteria attach to forming a pathogenic biofilm and over time, acid demineralisation and proteolytic destruction of the organic component of the enamel and dentine takes place (Young, Kutsch Whitehouse 2009). Dental Caries can be classified in several ways According to location-Caries may be restricted to pits and fissures but may also progress to expose the pulp. Restorative status of the tooth- Primary caries occurs on previously unrestored teeth whereas secondary caries occurs at margins of restorations {{52 Kidd,Edwina A.M. 2005}}. Secondary caries is caused by local factors that are involved in the formation of cariogenic plaque. Most secondary carious lesions develop at the gingival margins of restorations primarily in areas of stagnation areas (Mjà ¶r, 1998). Large gaps between the restoration and the wall of the cavity preparation can create an environment that favours secondary caries formation (Mjà ¶r, 1998). Secondary caries is also known as recurrent caries. Caries can be arrested whereby a lesion which was previously active has now stopped progressing. Fluoride: Mode of Action Fig 1: Demineralisation Process and the role of fluoride (Cury, Tenuta 2008) Figure one shows how sugars such as sucrose, glucose and fructose are converted to acids in the plaque biofilm. When the pH decreases below 5.5 (critical pH of enamel), the saliva is no longer supersaturated with calcium and phosphate. Therefore, demineralisation occurs. However, in the presence of fluoride and if the pH is higher than 4.5, hydroxyapatite is converted to fluorapatite which has a lower solubility. As a result, net demineralization is reduced and the dental hard tissues are more acid resistant. Tenuta and colleagues calculated that fluorapatite would not dissolve until the pH dropped below approximately 4.4. However, researchers have found that the effect of fluoride is not only due to the decreased solubility but also due to the effect of fluoride on the rates of demineralisation and remineralisation (Stoodley et al. 2008). In order to enter bacteria, fluoride must be combined with a hydrogen ion forming hydrogen fluoride (HF), which readily diffuses into the cell. Once inside the bacterial cell, the HF dissociates into fluoride and hydrogen ions. The fluoride inhibits intracellular bacterial enzymes such as enolase. As a result, less phosphoenolpyruvate and lactate are formed. The reduced lactate formation limits the ability of bacteria to cause caries. Similarly, the uptake of glucose is also reduced by fluoride {{63 Featherstone,J.D. September 2004}}. The fluoride concentration in saliva increases after brushing with a fluoride toothpaste. After three minutes, the concentration is 100 times greater than the baseline value (normally 0.03ppm or 1.6umol/l) {{65 Murray, J.J 1991}}. Two hours later, the concentration returns to normal. It is important to avoid rinsing out the mouth as the most profound effects of fluoride are within two hours of brushing. Fluoride is spread throughout the oral cavity and is stored in compartments on the tooth surface and the remaining pellicle (Cury, Tenuta 2008). Calcium Fluoride globules are formed and are reservoirs of fluoride, releasing it as the pH falls, thereby, reducing time spent in the demineralisation phase. The main effects of fluoride can be attributed to the maintenance of constant fluoride levels in the biofilm. Overall, fluoride has multiple ways of reducing caries. It is believed that the most important of these methods is the remineralisation concept {{40 Oganessian,E. 2007}}, which requires a constant flow of fluoride. Bacterial enzyme inhibition plays a supplementary role when the concentration of fluoride is high which is achieved by topical fluoride applications and toothpastes (Murray, Rugg-Gunn Jenkins 1991). Who is at risk of decay? There are certain groups in the population who are at risk of decay and therefore, would benefit from the use of fluoridated dentifrices. These include patients with: Xerostomia, which may have resulted from the radiotherapy to the head or neck leading to salivary gland exposure. This leads to a decrease in both the resting and stimulated salivary flow rates. Xerostomia is defined as the complete absence of saliva or hyposalivation. Hyposalivation leads to decreased levels of calcium, phosphate and hydrogen bicarbonate ions. As a result, there is a longer demineralisation phase Sjà ¶grens syndrome- this is clinically defined as at least two of kerataoconjuctivitis sicca, Xerostomia(dry mouth) and rheumatoid arthritis or another connective tissue disease {{62 Newbrun,E. 1996}} A high incidence of caries in their primary dentition Hypersensitivity Root caries Removable orthodontic appliances and partial dentures A poor diet and those who regularly snack on fermentable carbohydrates {{37 Evans,R.W. 2008}}. However, this risk has decreased due to better plaque control and increased fluoride exposure. Multiple restorations suggesting a high prevalence of caries Optimum fluoride concentration required for remineralisation Bjarnason and Finnbogason (1991) found that fluoride levels in dentifrices had no effect on the progression of enamel lesions detected radiographically. However, a higher fluoride concentration (1000ppm F-) led to reduction in caries initiation compared to a dentifrice with a lower fluoride concentration (250ppm F-) {{69 Bjarnason, S. 1991}}. It is ultimately difficult to decide the optimum fluoride concentration required for remineralisation as different areas of the mouth are more at risk of caries due to unique ecological factors. However, it was thought that lesion progression in enamel was slowed down only in patients with low caries activity whereas patients with high caries activity still experienced rapid progression (Hellwig, Lussi 2001). DMF Index The DMF index is a measure of caries activity in a population and changes in the DMF index can be used to highlight the protective effects of the fluoride toothpastes and varnishes (Kidd 2005). D: decayed teeth with untreated carious lesions M: missing teeth (extracted teeth) F: filled teeth DMFT denotes decayed, missing and filled teeth DMFS denotes decayed, missing and filled surfaces in permanent teeth and therefore, the number of surfaces attacked on each tooth are accounted for. There are similar indices for deciduous tooth, which are the defs and deft scores. The e represents extracted teeth to differentiate(Johansen et al. 1987) between natural loss of teeth through exfoliation. Burt in 1998 suggested that greater emphasis has to be placed on the assessment and early diagnosis of caries {{77 Burt, B.A. 1998}}. This has been backed up by cohort studies {{83 Johansen, E. 1987}} (Axelsson, Lindhe Nystrom 1991), which found that the use of preventive strategies (fluoride application) resulted in a substantial reduction in lesion development and progression. Fluoride varnishes What is fluoride varnish? Fluoride varnish was first developed in New York in 1968 by Heuser and Schmidt in the form of sodium fluoride and was marketed under the name Duraphat. The Duraphat varnish contains 22,600 parts per million of fluoride (ppm Fˆ°) as shown in figure 2. In the 1970s, there was a switch from sodium fluoride to difluorsilane which was marketed under the name Fluor Protector (7000ppm Fˆ°) in Germany {{42 Azarpazhooh,A. 2008}}. Fluoride Varnish Type of fluoride Fluoride Concentration(ppm) Fluoride Concentration(%) Duraphat Sodium Fluoride 22,600 2.26 Duraflor Sodium Fluoride 22,600 2.26 Fluor protector Difluorsilane 7,000 0.70 Fig 2: The table above shows the fluoride varnishes that are most commonly used. Other types of fluoride varnishes include: Fluoride Varnish Type of fluoride Fluoride Concentration(ppm) Fluoride Concentration (%) Lawefluor Sodium Fluoride 22,600 2.2 Bifluorid Sodium and Calcium Fluoride 56,300 5.6 Fig 3: The table above shows other fluoride varnishes which are available but are less commonly used {{24 Davies,G.M. 2008}}. Most fluoride varnishes contain fluoride in an alcoholic solution of natural tree resin. The main advantage of the varnish is that the resin base is very adherent to the tooth prolonging contact time between the fluoride and enamel {{26 Miller,E.K. et al 2008}}. Varnishes are easy to apply and relatively safe regardless of the high fluoride concentration as the amount of varnish applied to one child is only 0.5 ml on average (Ripa 1990; Petersson 1993). Varnishes are slow-releasing reservoirs of fluoride preventing immediate release of fluoride after application (Ogaard 1994). As a result, they are most effective at protecting against primary caries. The food and drug administration centre in America has not yet accepted fluoride varnish as an anti-caries agent but considered it as a liner/desensitising agent (Mason 2005). There is some debate as to the amount of fluoride taken up by the tooth surfaces. It was found that approximately half of the fluoride taken up by sound surfaces from Fluor Protector varnish was lost after 6 months suggesting that the large amount of fluoride taken up after one week does not bind permanently to enamel and that the effects of fluoride are more short term. There has also been a debate over whether fluoride varnish should be applied to wet or dry surfaces. Koch et al found that the fluoride uptake was much greater when the varnish was applied to dry tooth surfaces (Koch, Hakeberg Petersson 1988). Fluoride varnishes can be applied professionally up to two to four times a year. Marinho et al in 2002 investigated the effectiveness of fluoride varnish in preventing dental caries in children compared to a placebo or no treatment. Over 2700 systemically healthy children aged 16 or less received fluoride varnish containing 22,600ppm sodium fluoride. There was a large caries inhibiting effect on both permanent and deciduous dentition. However, the confidence intervals were relatively wide and the variation among the results was substantial. The success of the treatment may have been over estimated, as the results of the few trials may not have been representative. As a result, it is important to carry out more trials before a definite statement can be made of the effects of the fluoride varnish (Marinho 2002). In addition, more information is required on the scale of the fluoride effect and the adverse effects of fluoride. Effect on the DMFT/dmft Primary Dentition There was a 33% decrease in the decayed, missing and filled surfaces (Marinho 2002). A two year randomised clinical trial carried out on children with a mean age of 1.8 years, found that the application of fluoride varnish once, twice and three times a year reduced the mean dmfs by 53%, 58% and 93% respectively {{67 Davies,G.M. 2009}}. This highlights the importance of frequent varnish application. (Petersson, Twetman Pakhomov 1998)Petersson et al. in 1998 found a 19% and 25% reduction in the increment of approximal caries in children with a moderate or high caries risk respectively. This shows that children with a high caries risk benefit the most from the application of fluoride varnishes (Zimmer 2001). Ages 0-3 Weintraub and colleagues carried out a two year randomised controlled trial on 376 children aged between 6-44 months (Weintraub et al. 2006). The children were split into three groups: Those who received counselling Those who received counselling and the annual application of Duraphat Those who received counselling and the twice yearly application at six monthly intervals The number of lesions only increased in children who received counselling alone highlighting the protective effects of the varnish. Those children who received no varnish application were twice as likely of developing decay as those who received the annual application of fluoride. As the frequency of fluoride varnish application increased, the number of carious lesions decreased. One drawback of this trial was that simultaneous counselling and varnish application led to some ambiguity as to whether the effects were due to varnish application or counselling although fluoride application was seen to play a key role. Ages 3-6 According to the Cochrane Review, there was an overall 38% reduction in the DMFS/dmfs (Marinho 2002). A two year randomised study of 1,275 children in Canada aged between 6 months and 5 years found that twice-yearly application of Durafluor led to an 18.3% reduction in the dmfs increment (Lawrence et al. 2006). Mixed dentition There was on average a 46% decrease in dmfs. The fluoride varnish was an effective preventive measure for partially erupted permanent molars. Equally, patients who are insufficiently co-operative benefit from fluoride varnish application (Marinho 2002). Permanent dentition A randomised clinical trial used to examine the impact of fluoride varnish on the incidence of approximal caries, detected radiographically in 13 year olds over a three year period, found that the varnish applied monthly and twice a year reduced caries by 76% and 57% respectively again highlighting the importance of frequent fluoride application{{67 Davies,G.M. 2009}}. The caries reduction in permanent teeth shown in the Cochrane review of trials was similar to that achieved in a metaanalysis carried out by Helfenstein in 1994 when Duraphat was applied 2 times a year in children aged 9-15 years (Helfenstein, Steiner 1994). There was a 38% reduction in the caries. It is likely that most of the participants benefited from the use of a fluoridated dentifrice as the majority of the studies were carried out in Scandinavian countries between 1973 and 1987. However, as both the Cochrane review and the Helfenstien study were carried out involving a different selection criteria, it is debatab le as to whether the results from both these trials can be compared. In conclusion, application of fluoride varnish two to four times a year on both permanent and deciduous teeth is associated with a reduction in the caries increment (Marinho 2002). The effect of fluoride varnish according to different caries risks Mà ¶berg Skold carried out a trial which involved the application of fluoride varnish to approximal caries in adolescents living in different caries risk areas. The trial involved 758 students aged between 13 to16 years old. The large sample size meant that the results of this study were representative. This is because as the sample size increases, the variability of the results decreases. This means that the results have a greater statistical power and smaller confidence intervals. Fig 4: (Azarpazhooh, Main 2008) The figure above shows the groups which were chosen according to their caries risk and whether they had any fluoride in their tap water. Duraphat was applied to the approximal surfaces from the distal surface of the canines to the mesial surface of the second molars. Each group had different intervals of application shown in the figure below: Group No. of participants Frequency of Duraphat application One 190 Twice yearly in six-monthly intervals ( 6 times in 3 years) Two 186 Three times a year with a one week period each year(9 times in 3 years) Three 201 Eight times a year during school terms with one month intervals ( 24 times in 3 years) Four(Control) 181 No application Fig 5: (Azarpazhooh, Main 2008) The frequency of Duraphat application The results from this trial show that the biggest difference was between group one and the control group in high caries risk area (Gà ¶teborg). However, there was no significant difference between the groups regarding filled approximal lesions and approximal enamel lesions. There was a greater incidence of caries in the control group in comparison to the fluoride varnish groups in all risk areas highlighting the protective effects of the fluoride varnish (Mà ¶berg Skold et al. 2005). Overall, it was found that the school based monthly application of fluoride varnish is the best method of preventing approximal caries in areas of medium and high caries risk (Mà ¶berg Skold et al. 2005). School based prevention programmes A cluster randomised trial was carried out by M.C Hardman and colleagues involving 2,091 school children living in a non-fluoridated area. One group of students (1,025 students) received the twice-yearly application of Colgate Duraphat varnish whilst the other group (1,066 students) served as a control. This study found that the twice-yearly application of fluoride varnish did not lead to a reduction in caries in children living in the community {{43 Hardman,M.C. 2007}}. This is contrary to what was found by Marinho and colleagues. They found that the biannual application of Duraphat in a school-based programme provided a caries inhibition of 38% in children aged 9-15 years (Marinho 2002). The study carried out by M.C Hardman and colleagues did not prove to be conclusive as the level of consent in the community was low. Approximately 110 students were lost during the study. The control group had lower caries levels than anticipated and therefore, it was difficult to tell the true eff ect of fluoride. In addition, the application of varnish was carried out under sub-optimal conditions (teeth could not be cleaned prior to application and the consumption of food and drink after application could not be controlled), which could have resulted in less profound effects. In conclusion, it was found that this type of fluoride varnish intervention is not effective in the prevention of caries in the public {{43 Hardman,M.C. 2007}}. A similar study was carried in a small town located in the American Southwest on children attending a head start nursery using Duraflor as the varnish of choice. The trial began in the head start class of 2002. Duraflor was applied during well child visits every 9, 12, 15, 18, 24 and 30 months. The class of 2003 had no fluoride application and therefore, served as the control. The mean age was 4.40 years and approximately 168 males and 189 females took part. The results showed that children who received no treatment had a mean dmfs of 23.6 with a 95% confidence interval. Those children who received 1-3 treatments had a similar dmfs to those with no treatment. Only those children who had 4 to 5 treatments showed a reduction in dmfs again suggesting the importance of frequent application. However, this study was an observational study not a randomised study and therefore, the reliability of the results can be questioned. In addition, no attempt was made to determine whether the childre n who received four or more applications of fluoride varnish differed from the other children in terms of diet and oral hygiene history {{58 Holve,S. 2008}}.. The use of fluoride varnish in inhibiting secondary carious lesions As mentioned earlier, secondary caries forms at the margins of restorations. Larger amounts of fluoride varnish may be trapped in the gap formed between the restoration and the cavity wall. This may serve as a slow releasing reservoir of fluoride, which could also provide a physical barrier against wall dissolution. In a study carried out by M. Fontana in 1996, two experiments were carried out. Experiment one involved the application of Duraflor. Experiment two involved the application of Duraphat a year after the application of Duraflor. The effects of fluoride varnish on secondary caries remineralisation and lesion progression were measured. The varnish was applied to dry tooth surfaces and rinsing after fluoride application was prevented to enhance the remineralisation potential. The varnish was applied for 24 hours to prolong the contact time between the varnish and the tooth surface. The results from these two experiments showed that fluoride application slowed down lesion progression around both amalgam and composite restorations {{48 Fontana, M. 2002}}. The placebo varnish slowed down lesion progression to a lesser extent than the fluoride varnish suggesting that the effects may not only be attributed to the fluoride in the varnish. These results matched those in a previous study carried out by Hellwig et al. in 1993. They examined the effect of Duraphat varnish on artificially created primary carious lesions and found that fluoride varnish led to remineralisation in the outer layers of enamel {{78 Hellwig, E.K. 1993}}. This slowed down lesion progression. Seppa suggested in 1988 that the benefits of fluoride varnish were attributed to their ability to enhance remineralisation of primary caries rather than their ability to increase the fluoride content of the tooth surface. This is contrary to what was previously thought that the effects of topical fluoride were due to their ability to maintain high levels of fluoride on the surface of the tooth. Seppa also found that the efficacy of the fluoride varnishes was dependent on the number of applications rather than the concentration of fluoride {{79 Seppà ¤, L. 1988}}. This backs up the results found by Marinho et al that showed that the more frequent the applicati on, the lower the incidence of new caries or the greater the decrease in mean dmfs/DMFS. Fluoride toothpaste What is fluoride toothpaste? Fluoride toothpaste is the most widely used method of fluoride application in the population due to its ease of use. Fluoride toothpastes can be incorporated into community and school based prevention programmes. Most oral health care workers recommend brushing twice a day, once just before going to bed, as this is when saliva flow is at its lowest and once at another time of day{{68 Davies,R.M. 2003}}. They recommend spitting out the toothpaste after use rather than rinsing as this dilutes the fluoride concentration in the oral cavity as previously mentioned. The widespread use of fluoride toothpastes had made it more difficult to distinguish whether a reduction in caries is due to mechanical plaque removal or due to the incorporation of fluoride. Before the widespread use of fluoride toothpastes, the importance of fluoride was illustrated in a three-year study. This study involved two groups of children aged 9 to 11 years who had benefited from supervised brushing either with or without fluoride toothpaste. Both groups showed a reduction in plaque and gingivitis but a significant reduction in caries was only seen in the group which used fluoridated toothpastes (Davies et al. 2003). A typical toothpaste contains abrasives such as calcium carbonates, which help to remove surface debris, and stains on the tooth surface. Most toothpastes contain fluoride (added to toothpastes in the 1970s) to make the tooth more resistant to acid attack and is one of the most recognised agents in toothpastes. Stannous fluoride (also known as tin fluoride) was the first fluoride to be used due to its compatibility with the abrasive, calcium phosphate. Sodium fluoride could not be used at first as the calcium in the abrasive renders it ineffective and therefore, is not compatible. Sodium Monofluorophosphate was next used as it was compatible with the abrasives used with it. Sodium Fluoride could only be used when hydrated silica and sodium bicarbonate became the abrasive of choice. Studies have shown that the sodium bicarbonate-sodium fluoride combination lead to a caries reduction of one surface per child over two years (Murray, Rugg-Gunn Jenkins 1991). Fluorides have been shown to work better in combination with detergents such as sodium lauryl sulphates, which aid the remineralisation process and create foaming whilst brushing. Toothpastes contain humectants such as glycerol, which prevent the loss of water in the toothpaste. To provide taste, saccharin and other sweeteners are added. To stabilise the toothpaste, thickening agents such as seaweed colloids are included to ensure that the toothpaste stays on the toothbrush when it is applied. The use of fluoride toothpastes in clinical trials The Cochrane review of trials found that children who used fluoridated toothpaste had fewer decayed,missing and filled permanent teeth after three years. Brushing twice a day helps to increase the benefit of fluoride (Marinho et al. 2003 England). Researchers believe that the effects of fluoridated toothpastes are underestimated in two to three year trials due to the life long used of fluoride. They also found that the use of fluoride toothpastes in areas of fluoridated water increased the protective effects. The normal concentration of fluoride in toothpastes is between 1000 and 1100 parts per million (ppm Fˆ°). Toothpastes with higher fluoride concentrations (1500ppm) and lower fluoride concentrations (500ppm) are available in many countries. Toothpastes containing higher fluoride concentrations offer greater protection against caries (Stephen 1988; OMullane 1997). Since the 1940s, more than a 100 clinical trials have been carried out and by the late 1970s, the protective effects of fluoride toothpastes were greatly accepted. As a result, many clinical trials could not have a control, as the removal of fluoride toothpaste for the trial was considered unethical. Therefore, the effectiveness of different concentrations of fluoride toothpastes have not been investigated extensively in placebo-controlled trails. The guidelines of caries trials have since been changed in order to combat this problem, by increasing the sample size so that the measurement error could be reduced (Marinho et al. 2003 England). Children or adolescents aged sixteen or less were chosen to take part in the study carried out by Marinho et al. To assess the effect of the fluoride toothpaste, the caries increment was measured as a change in the value of the DMFS Index, in all permanent teeth erupted at the start and erupting over the course of the study. Evidence from this study suggested that the use of fluoride toothpastes leads to a 24% decrease in dmfs. The confidence intervals for this reduction were 21-28%. This means that 1.6 children need to brush with fluoride toothpaste to prevent one decayed, missing or filled tooth surface in a population where the caries increment is 2.6 DMFS per year. Where the caries increment was lower (1.1 DMFS per year), 3.7 children needed to use a fluoride toothpaste in order to avoid one decayed, missing or filled tooth surface(Marinho et al. 2003 England). There was also a substantial reduction in caries increment (37%) of deciduous teeth in a trial carried out on 2008 children aged 6 to 9 years. Another aim of the Cochrane review (Marinho et al. 2003 England) was to establish whether there was any relationship between the caries-preventive effects of fluoride toothpaste and the initial level of caries, previous exposure to fluoride and the frequency of fluoride toothpaste use on the prevented fraction. The prevented fraction (PF) is the proportion of disease occurrence in a population averted due to a protective risk factor or public health intervention (Gargiullo, Rothenberg Wilson 1995). The prevented fraction was measured as the diffe

cloning :: essays research papers

Cloning humans and organs could only yield new technologies that will be beneficial to society. Organ cloning is something that would be extremely beneficial to society. For example, if we could clone human organs there would be no need for waiting lists for people looking for donors. Scientist could make a clone of a patient’s organ, that their body would be more likely to accept, without the imperfections of their previous organ. This way, another person who was on the waiting list could receive the organ. In America there are thousands of people on waiting lists to receive new organs that will help prolong their life. Many of these people will die because there is not a suitable donor that matches their needs. Imagine the lives that will be saved if an individual can clone their own liver, or any other organ that is needed to survive an illness. The process is fairly uncomplicated. When a child is conceived, doctors will take a few cells from it and clone them. These cells will then be placed in a national tissue bank until needed. There they are readily available. If the child gets hurt, or contracts a disease, it will have a â€Å"repair kit† to fall back on. Most of the controversy is over whether or not we will be killing another human in order to get these parts. In a sense, we would. The frozen embryo would be placed in a surrogate mother. There it needs only a mere week to grow. It can then be removed, and the needed organ singled out. Then, this organ can be grown in a lab, where scientists can speed up the process greatly. Yes, we did create the beginnings of a human, but it was only one week old. Whether or not people believe in the "art" of cloning you have to agree that there are definitely good things that can come from all of this research. Researchers say that within 5-10 years we will actually be able to grow headless human clones. I’m not saying that this should be ethical to everyone, but just imagine the possibilities. No more waiting lists, and nearly uliminating organ rejection should be and exiting prospect to everyone. This type of technology could save thousands of lives. Using just the embryonic cloning, we could drastically improve many people’s chance to live. . Cloning has the ability to change the face of the planet forever. cloning :: essays research papers Cloning humans and organs could only yield new technologies that will be beneficial to society. Organ cloning is something that would be extremely beneficial to society. For example, if we could clone human organs there would be no need for waiting lists for people looking for donors. Scientist could make a clone of a patient’s organ, that their body would be more likely to accept, without the imperfections of their previous organ. This way, another person who was on the waiting list could receive the organ. In America there are thousands of people on waiting lists to receive new organs that will help prolong their life. Many of these people will die because there is not a suitable donor that matches their needs. Imagine the lives that will be saved if an individual can clone their own liver, or any other organ that is needed to survive an illness. The process is fairly uncomplicated. When a child is conceived, doctors will take a few cells from it and clone them. These cells will then be placed in a national tissue bank until needed. There they are readily available. If the child gets hurt, or contracts a disease, it will have a â€Å"repair kit† to fall back on. Most of the controversy is over whether or not we will be killing another human in order to get these parts. In a sense, we would. The frozen embryo would be placed in a surrogate mother. There it needs only a mere week to grow. It can then be removed, and the needed organ singled out. Then, this organ can be grown in a lab, where scientists can speed up the process greatly. Yes, we did create the beginnings of a human, but it was only one week old. Whether or not people believe in the "art" of cloning you have to agree that there are definitely good things that can come from all of this research. Researchers say that within 5-10 years we will actually be able to grow headless human clones. I’m not saying that this should be ethical to everyone, but just imagine the possibilities. No more waiting lists, and nearly uliminating organ rejection should be and exiting prospect to everyone. This type of technology could save thousands of lives. Using just the embryonic cloning, we could drastically improve many people’s chance to live. . Cloning has the ability to change the face of the planet forever.