9,101 research outputs found

    On the D0D^0 -- DsD_s lifetime difference and τ7π+ντ\tau\to 7\pi + \nu_\tau decays

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    In this paper we discuss some aspects of inclusive decays of charmed mesons and also decays of the τ\tau lepton into ντ+7π\nu_\tau + 7\pi. We find that phase space effects are likely to explain the observed lifetime ratio τ(Ds+)/τ(D0)\tau(D_s^+) / \tau(D^0) = 1.17. In particular one need not appeal to a large annihilation contribution in the inclusive D0D^0 decay which, being absent in Ds+D_s^+ decays could also contribute to the enhanced D0D^0 decay rate relative to that of the Ds+D_s^+. Examining a separate problem, we find that the rate for τντ+7π\tau\to \nu_\tau + 7\pi is almost completely dominated by the tiny phase space for the final eight particle state. Using an effective chiral Lagrangian to estimate the matrix element yields a branching ratio into the channel of interest far smaller than the present upper bound.Comment: No figure

    Leadership for Higher Education – Role of a Dean

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    The role of the academic dean is often a difficult one to describe. As a leader in higher education the dean has various responsibilities and many challenges to face that tend to evolve with the ever-changing face of higher education. The role of the academic dean is one that is multifaceted, challenging and often ambiguous. (Walker, 2000) The dean is a person the students could go to in times of trouble and in times of prosper, and to learn from the dean about life. It is essential that deans have the required knowledge base, skills and abilities to perform effectively in this demanding role

    Dental Public Health! A Mistaken Identity

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    The dental public health field has been expanding in scope & complexity with more emphasis being placed on the total dental care delivery system and its impact on oral health status. A broadly accepted definition of “dental public health” has been given by Downer 1994: “The science and art of preventing oral disease, promoting oral health and improving quality of life through the organized efforts of society” (Downer et al,1994). A broader definition was made ten years later as follows: “The science and art of preventing oral disease, promoting oral health and improving quality of life through the organized efforts and informed choices of society, organizations, public and private, communities and individuals” (Pine & Harris 2007). The purpose of an oral health care system is to influence the population’s way of life so that oral health is promoted or maintained and oral disease prevented; and to promote adequate treatment to those members of the population affected by oral disease so that disease is arrested at an early stage and loss of function is prevented. These functions apply whether the service is in a developing or developed country

    Ethical Issues in Higher Education and Scientific Research: Erosion of Academic Integrity

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    Ethics is the cornerstone of dental research or for that matter any research. Authorship in a scientific research is an important issue which requires considerable debate. The pressure to publish is well-established in the university community. Faculty member’s performance and promotion are judged by the number of published articles in academic scholarly journals. If survival means publish or perish, any and every effort to see one’s name in print becomes important. In such a situation, we should not be surprised to see the operation of the cliché, “You scratch my back, I’ll scratch yours” (Lazar, 1995)

    Eliminating Health Discrepancies: Insights through Free market or State control

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    Healthcare inequality or healthcare disparity refers to the differences in the quality of health and health care across different populations. This may include differences in the prevalence of disease, health outcomes, or access to health care across racial, ethnic, gender, and socioeconomic groups. Differences among populations in the presence of disease and health outcomes are well documented in many areas. In the United States, disparities are well documented in minority populations such as African Americans, Native Americans, Asian Americans, and Latinos, with these groups having higher incidence of chronic diseases, higher mortality, and poorer overall health outcomes. For example, the cancer incidence rate among African Americans is 10% higher than among whites, and adult African Americans and Latinos have approximately twice the risk as whites for developing diabetes. Similarly, disparities in the overall level of health in individuals also exist between differing socioeconomic groups, with lower-status socioeconomic groups generally having poorer health and higher rates of chronic illness including obesity, diabetes, and hypertension. Those in lower socioeconomic status groups receive less consistent primary care, which is positively correlated to overall level of health in the recipient. Similarly, in England, people living in deprived areas were found to receive around 70% less provision relative to need compared with the most affluent areas for both knee and hip replacements

    Future fuels and engines for railroad locomotives. Volume 1: Summary

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    The potential for reducing the dependence of railroads on petroleum fuel, particularly Diesel No. 2 was investigated. Two approaches are studied: (1) to determine how the use of Diesel No. 2 can be reduced through increased efficiency and conservation, and (2) to use fuels other than Diesel No. 2 both in Diesel and other types of engines. Because synthetic hydrocarbon fuels are particularly suited to medium speed diesel engines, the first commercial application of these fuels may be by the railroad industry