8 resultados para Flavor-changing neutral current

em Digital Commons at Florida International University


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We have obtained total and differential cross sections for the strangeness changing charged current weak reaction ν L + p → Λ(Σ0) + L+ using standard dipole form factors, where L stands for an electron, muon, or tau lepton, and L + stands for an positron, anti-muon or anti-tau lepton. We calculated these reactions from near threshold few hundred MeV to 8 GeV of incoming neutrino energy and obtained the contributions of the various form factors to the total and differential cross sections. We did this in support of possible experiments which might be carried out by the MINERνA collaboration at Fermilab. The calculation is phenomenologically based and makes use of SU(3) relations to obtain the standard vector current form factors and data from Λ beta decay to obtain the axial current form factor. We also made estimates for the contributions of the pseudoscalar form factor and for the F E and FS form factors to the total and differential cross sections. We discuss our results and consider under what circumstances we might extract the various form factors. In particular we wish to test the SU(3) assumptions made in determining all the form factors over a range of q2 values. Recently new form factors were obtained from recoil proton measurements in electron-proton electromagnetic scattering at Jefferson Lab. We thus calculated the contributions of the individual form factors to the total and differential cross sections for this new set of form factors. We found that the differential and total cross sections for Λ production change only slightly between the two sets of form factors but that the differential and total cross sections change substantially for Σ 0 production. We discuss the possibility of distinguishing between the two cases for the experiments planned by the MINERνA Collaboration. We also undertook the calculation for the inverse reaction e − + p → Λ + νe for a polarized outgoing Λ which might be performed at Jefferson Lab, and provided additional analysis of the contributions of the individual form factors to the differential cross sections for this case. ^

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Growing demand for handwoven Maya textiles from Guatemala parallels recent international fascination with Maya civilization. This thesis surveys the effects of increases in demands for artisan textiles in Guatemala, and explores the reactions of women involved in Aj Quen, a weavers' association. The hypothesis is that the well-being of Maya women depends on their participation in the association. This is tested by using indicators of the weavers' attitudes defined as their "well-being" regarding (1) health, (2) education levels, (3) child care practices, and (4) economic stability. Interviews were conducted with 127 Maya women. Data were documented, providing a crucial missing link in the current literature of "women in Guatemala." The results of this study yield baseline data demonstrating that health and child care practices are not directly related to women's participation in the association. Their education levels increased as a direct result of working with the association, as did economic stability, although less consistently.

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The current U.S. health care system faces numerous environmental challenges. To compete and survive, health care organizations are developing strategies to lower costs and increase efficiency and quality. All of these strategies require rapid and precise decision making by top level managers. The purpose of this study is to determine the relationship between the environment, made up of unfavorable market conditions and limited resources, and the work roles of top level managers, specifically in the settings of academic medical centers. Managerial work roles are based on the ten work roles developed by Henry Mintzberg, in his book, The Nature of Managerial Work (1973). ^ This research utilized an integrated conceptual framework made up of systems theory in conjunction with role, attribution and contingency theories to illustrate that four most frequently performed Mintzberg's work roles are affected by the two environment dimensions. The study sample consisted of 108 chief executive officers in academic medical centers throughout the United States. The methods included qualitative methods in the form of key informants and case studies and quantitative in the form of a survey questionnaire. Research analysis involved descriptive statistics, reliability tests, correlation, principal component and multivariate analyses. ^ Results indicated that under the market condition of increased revenue based on capitation, the work roles increased. In addition, under the environment dimension of limited resources, the work roles increased when uncompensated care increased while Medicare and non-government funding decreased. ^ Based on these results, a typology of health care managers in academic medical centers was created. Managers could be typed as a strategy-formulator, relationship-builder or task delegator. Therefore, managers who ascertained their types would be able to use this knowledge to build their strengths and develop their weaknesses. Furthermore, organizations could use the typology to identify appropriate roles and responsibilities of managers for their specific needs. Consequently, this research is a valuable tool for understanding health care managerial behaviors that lead to improved decision making. At the same time, this could enhance satisfaction and performance and enable organizations to gain the competitive edge . ^

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Freeze events significantly influence landscape structure and community composition along subtropical coastlines. This is particularly true in south Florida, where such disturbances have historically contributed to patch diversity within the mangrove forest, and have played a part in limiting its inland transgression. With projected increases in mean global temperatures, such instances are likely to become much less frequent in the region, contributing to a reduction in heterogeneity within the mangrove forest itself. To understand the process more clearly, we explored the dynamics of a Dwarf mangrove forest following two chilling events that produced freeze-like symptoms, i.e., leaf browning, desiccation, and mortality, and interpreted the resulting changes within the context of current winter temperatures and projected future scenarios. Structural effects from a 1996 chilling event were dramatic, with mortality and tissue damage concentrated among individuals comprising the Dwarf forest's low canopy. This disturbance promoted understory plant development and provided an opportunity for Laguncularia racemosa to share dominance with Rhizophora mangle. Mortality due to the less severe 2001 event was greatest in the understory, probably because recovery of the protective canopy following the earlier freeze was still incomplete. Stand dynamics were static over the same period in nearby unimpacted sites. The probability of reaching temperatures as low as those recorded at a nearby meteorological station (≤3 °C) under several warming scenarios was simulated by applying 1° incremental temperature increases to a model developed from a 42-year temperature record. According to the model, the frequency of similar chilling events decreased from once every 1.9 years at present to once every 3.4 and 32.5 years with 1 and 4 °C warming, respectively. The large decrease in the frequency of these events would eliminate an important mechanism that maintains Dwarf forest structure, and promotes compositional diversity.

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Resorts in the future will be feeling the effect of a number of changes in the industry. Changing demographics, economic conditions and the changing priorities of resort guests will play major roles in the future success of resort properties. The authors stress that future resort marketing should emphasize the expansion of current market segments, the creation of new market segments, and hte expansion of qualirty services.

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In - Commuter Airlines: Their Changing Role – an essay by J. A. F. Nicholls, Transportation Coordinator, Department of Marketing and Environment, College of Business Administration, Florida International University, Nicholls initially observes: “The great majority of airline passenger miles flown in the United States are between large conurbations. People living in metropolitan areas may be quite unaware of commuter airlines and their role in our transportation system. These airlines are, however, communications lifelines for dwellers in small - and not so small - towns and rural areas. More germanely, commuter airlines have also developed a pivotal role vis-a-vis the major carriers in this country. The author discusses the antecedents of the commuter Airlines, their current role, and future prospects.” Huh; conurbations? Definition: [n.] a large urban area created when neighboring towns spread into and merge with each other In providing a brief history on the subject of commuter airlines, Nicholls states: “…there had been a sort of commuter airline as far back as 1926 when, for example, the Florida Airways Corporation provided flights between Jacksonville and Atlanta, Colonial Air Lines between New York and Boston, and Ford Air Transport from Detroit to Cleveland.” “The passage of the Civil Aeronautics Act in 1938 was pivotal in encouraging and developing a passenger orientation by the airlines…” Nicholls informs you. Nicholls provides for the importance of this act by saying: “The CAA was empowered to act “in the public interest and in accordance with the public convenience and necessity.” Only the CAA itself could determine what constituted the “public convenience and necessity.” Nobody, however, could provide air transportation for public purposes without a Certificate of Public Convenience and Necessity, dispensed by the CAA.” The author wants you to know that this all happens in the age of airline regulation; that is to say, pre de-regulation i.e. 1978. Airlines could not and did not act on their own behalf; their actions were governed by the regulating agency, that being the Civil Aeronautics Board [CAB], who administered the conditions set forth by the CAA. “In 1944 the CAB introduced a new category of service called feeder airlines to provide local service-short-haul, low density-for smaller communities. These carriers soon became known as air taxis since they operated as common carriers, without a regular schedule,” says Nicholls in describing the evolution of the service. In 1969 the CAB officially designated these small air carriers as commuter airlines. They were, and are subject to passenger limits and freight/weight restrictions. Nicholls continues by defining how air carriers are labeled and categorized post 1978; in the age of de-regulation.

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An exploration of how current HRDM managers can stimulate change in order to motivate social justice.

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Growing demand for handwoven Maya textiles from Guatemala parallels recent international fascination with Maya civilization. This thesis surveys the effects of increases in demands for artisan textiles in Guatemala, and explores the reactions of women involved in Aj Quen, a weavers' association. The hypothesis is that the well-being of Maya women depends on their participation in the association. This is tested by using indicators of the weavers' attitudes defined as their "well-being" regarding 1) health, 2) education levels, 3) child care practices, and 4) economic stability. Interviews were conducted with 127 Maya women. Data were documented, providing a crucial missing link in the current literature of "women in Guatemala." The results of this study yield baseline data demonstrating that health and child care practices are not directly related to women's participation in the association. Their education levels increased as a direct result of working with the association, as did economic stability, although less consistently.