476 research outputs found

    The interactions of 300 MEV negative PI-Mesons with complex Nuclei

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    A stack of emulsion pellicles has ben exposed to a 300 MeV beam of π(^-)-mesons and their interactions with nuclei have been observed by following 140 m of track. In order to analyse the events the usual techniques have been employed in addition to which a new method due to the author of measuring the ionization of tracks, steeply inclined to the emulsion plane, is presented. The interation lengths for the production of inelastic interactions and elastic scatterings are (37.9 ± 2.0)cm and (77.4 ± 5.8)cm respectively. An optical model analysis leads to an absorption coefficient and change in wave number of (1.5 ± 0.15) 10(^12) cm(^-1) and (1.32 ± 0.12) 10(^12) cm(^-1) respectively. The differences from the expected values are consistent with a reduction of the cross-section for elastic scattering within the nucleus of about 3 times. The average energy for inelastically scattered pions varies with the angle of scattering and resembles that for the scatting of pions by free, stationary nucleons except that the energy in the forward direction is somewhat reduced. The angular distribution for the scattered pions is somewhat reduced. The angular distribution for the scattered pions shows near isotropy whereas the equivalent graph for scatting on free nucleons is strongly peaked in for the forward direction. A mode of interaction in which only a single collision of the pion with a nucleon occurs is, proposed. The pion emerges without further collision and the struck nucleon goes on to make other collisions. The exclusion principle has been applied to an experimentally determined distribution of momentum in the nucleus and a strongly inhibitive effect results, producing an isotropic distribution of the secondary, pions and a lowering of the average energy of these pions in the forward direction. For absorption of the pion it is proposed that two absorbing nucleons are involved which go on to make other collisions. Energy balances have been performed on the inelastic scatterings and absorptive events. They show good agreement with the available energy

    Teachers\u27 Efforts to Support Undocumented Students Within Ambiguous Policy Contexts

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    Although education scholars have recently focused greater attention on the experiences of undocumented youth in schools, few studies have examined educators\u27 perceptions of their roles and responsibilities with regards to this population. Since the 1982 Supreme Court decision Plyler v. Doe guaranteed education to this group and barred schools from inquiring about immigration status, little additional policy has offered guidance on how schools can support this group while also refraining from identifying it\u27s members. Policies are particularly lacking in new destination areas where there are fewer resources and less infrastructure for new immigrant populations. As increasingly harsh immigration enforcement policies amplify fear and anxiety among families, educators and other service providers are more in need of support than perhaps ever before. Some teachers in new destination areas, however, have found ways to create safe and empowering spaces for undocumented students. We conducted a qualitative case study to explore how such educators understand their roles amidst both this policy void and a political climate in which immigration has become an especially contentious and divisive issue. We interviewed 18 teachers of immigrant students in one new destination area in Virginia, a state experiencing an increase in the undocumented population. We found that teachers took actions to enhance students\u27 feelings of security and normalcy through curricular decisions, emotional support, and even the provision of basic needs. Teacher\u27s actions, which were often spontaneous, adaptive, and resourceful, could be described as agile advocacy. These actions ranged from providing information to families to pushing for school and district policy changes. However, the teachers also encountered many barriers and few supports in these efforts. They felt largely alone and frustrated by the incomprehensibility of the immigration system and the absence of building-and district-level leadership in support of undocumented students

    A hazard model of the probability of medical school dropout in the United Kingdom

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    From individual level longitudinal data for two entire cohorts of medical students in UK universities, we use multilevel models to analyse the probability that an individual student will drop out of medical school. We find that academic preparedness—both in terms of previous subjects studied and levels of attainment therein—is the major influence on withdrawal by medical students. Additionally, males and more mature students are more likely to withdraw than females or younger students respectively. We find evidence that the factors influencing the decision to transfer course differ from those affecting the decision to drop out for other reasons

    Cultural Orientations of sport managers

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    Various interpretations of sport management are cultural constructs underpinned by core assumptions and values held by members of professional communities. Sport managers world wide share common problems, but differ in how they resolve them. These universal differences emerge from the relationships they form with other people, and their attitude to time, activities and the natural environment. This paper examines the role of sport managers’ cultural orientations in the interpretation and practice of sport management. Using a multiple dimension model (Hampden-Turner and Trompenaars, 2000) it sketches the cultural profiles of fifteen sport managers from seven countries. A combination of methods was employed including questionnaires, interviews and participant observation. It is contended that the culture of sport management concerns a social process by which managers get involved in reconciling seven fundamental cultural dilemmas in order to perform tasks and achieve certain ends. Thus, a knowledge of the cultural meaning of sport management in a particular country would equip sport managers with a valuable tool in managing both the cultural diversity of their own work forces and in developing appropriate cross-cultural skills needed for running international events, marketing campaigns, sponsorship deals and joint ventures

    Stratified care vs stepped care for depression : a cluster randomized clinical trial

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    Importance: Depression is a major cause of disability worldwide. Although empirically supported treatments are available, there is scarce evidence on how to effectively personalize psychological treatment selection. Objective: To compare the clinical effectiveness and cost-effectiveness of 2 treatment selection strategies: stepped care and stratified care. Design, Setting, and Participants: This multisite, cluster randomized clinical trial recruited participants from the English National Health Service from July 5, 2018, to February 1, 2019. Thirty clinicians working across 4 psychological therapy services were randomly assigned to provide stratified (n = 15) or stepped (n = 15) care. In stepped care, patients sequentially access low-intensity guided self-help followed by high-intensity psychotherapy. In stratified care, patients are matched with either low- or high-intensity treatments at initial assessment. Data were analyzed from May 18, 2020, to October 13, 2021, using intention-to-treat principles. Interventions: All clinicians used the same interview schedule to conduct initial assessments with patients seeking psychological treatment for common mental disorders, but those in the stratified care group received a personalized treatment recommendation for each patient generated by a machine learning algorithm. Eligible patients received either stratified or stepped care (ie, treatment as usual). Main Outcomes and Measures: The preregistered outcome was posttreatment reliable and clinically significant improvement (RCSI) of depression symptoms (measured using the 9-item Patient Health Questionnaire). The RCSI outcome was compared between groups using logistic regression adjusted for baseline severity. Cost-effectiveness analyses compared incremental costs and health outcomes of the 2 treatment pathways. Results: A total of 951 patients were included (618 women among 950 with data available [65.1%]; mean [SD] age, 38.27 [14.53] years). The proportion of cases of RCSI was significantly higher in the stratified care arm compared with the stepped care arm (264 of 505 [52.3%] vs 134 of 297 [45.1%]; odds ratio, 1.40 [95% CI, 1.04-1.87]; P = .03). Stratified care was associated with a higher mean additional cost per patient (£104.5 [95% CI, £67.5-£141.6] [139.83(95139.83 (95% CI, 90.32-$189.48)]; P < .001) because more patients accessed high-intensity treatments (332 of 583 [56.9%] vs 107 of 368 [29.1%]; χ2 = 70.51; P < .001), but this additional cost resulted in an approximately 7% increase in the probability of RCSI. Conclusions and Relevance: In this cluster randomized clinical trial of adults with common mental disorders, stratified care was efficacious and cost-effective for the treatment of depression symptoms compared with stepped care. Stratified care can improve depression treatment outcomes at a modest additional cost. Trial Registration: isrctn.org Identifier: ISRCTN1110618

    Levator anguli oris muscle based flaps for nasal reconstruction following resection of nasal skin tumours

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    <p>Abstract</p> <p>Background</p> <p>surgical excision remains the best tool for management of skin tumors affecting nasal skin, however many surgical techniques have been used for reconstruction of the nasal defects caused by excisional surgery. The aim of this work is the evaluation of the feasibility and outcome of levator anguli oris muscle based flaps.</p> <p>Methods</p> <p>Ninety patients of malignant nasal skin tumours were included in this study. Age was ranged from four to 78 years. For small unilateral defects affecting only one side ala nasi, levator anguli oris myocautaneous (LAOMC) flap was used in 45 patients. For unilateral compound loss of skin and mucus membrane, levator anguli oris myocautaneous mucosal (LAOMCM) flap was used in 23 patients. Very large defects; bilateral either LAOMC or LAOMCM flaps combined with forehead glabellar flaps were used to reconstruct the defect in 22 patients.</p> <p>Results</p> <p>Wound dehiscence was the commonest complication. Minor complications, in the form of haematoma and minor flap loss were managed conservatively. Partial flap loss was encountered in 6 patients with relatively larger tumours or diabetic co-morbidity, three of whom were required operative re-intervention in the form of debridement and flap refashioning, while total flap loss was not occurred at all.</p> <p>Conclusions</p> <p>Immediate nasal reconstruction for nasal skin and mucosal tumours with levator anguli oris muscle based flaps (LAOMC, LAOMCM) is feasible and spares the patient the psychic trauma due to organ loss.</p

    Graduates of different UK medical schools show substantial differences in performance on MRCP(UK) Part 1, Part 2 and PACES examinations

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    Background: The UK General Medical Council has emphasized the lack of evidence on whether graduates from different UK medical schools perform differently in their clinical careers. Here we assess the performance of UK graduates who have taken MRCP( UK) Part 1 and Part 2, which are multiple-choice assessments, and PACES, an assessment using real and simulated patients of clinical examination skills and communication skills, and we explore the reasons for the differences between medical schools. Method: We perform a retrospective analysis of the performance of 5827 doctors graduating in UK medical schools taking the Part 1, Part 2 or PACES for the first time between 2003/2 and 2005/3, and 22453 candidates taking Part 1 from 1989/1 to 2005/3. Results: Graduates of UK medical schools performed differently in the MRCP( UK) examination between 2003/2 and 2005/3. Part 1 and 2 performance of Oxford, Cambridge and Newcastle-upon-Tyne graduates was significantly better than average, and the performance of Liverpool, Dundee, Belfast and Aberdeen graduates was significantly worse than average. In the PACES ( clinical) examination, Oxford graduates performed significantly above average, and Dundee, Liverpool and London graduates significantly below average. About 60% of medical school variance was explained by differences in pre-admission qualifications, although the remaining variance was still significant, with graduates from Leicester, Oxford, Birmingham, Newcastle-upon-Tyne and London overperforming at Part 1, and graduates from Southampton, Dundee, Aberdeen, Liverpool and Belfast underperforming relative to pre-admission qualifications. The ranking of schools at Part 1 in 2003/2 to 2005/3 correlated 0.723, 0.654, 0.618 and 0.493 with performance in 1999-2001, 1996-1998, 1993-1995 and 1989-1992, respectively. Conclusion: Candidates from different UK medical schools perform differently in all three parts of the MRCP( UK) examination, with the ordering consistent across the parts of the exam and with the differences in Part 1 performance being consistent from 1989 to 2005. Although pre-admission qualifications explained some of the medical school variance, the remaining differences do not seem to result from career preference or other selection biases, and are presumed to result from unmeasured differences in ability at entry to the medical school or to differences between medical schools in teaching focus, content and approaches. Exploration of causal mechanisms would be enhanced by results from a national medical qualifying examination

    Mapping medical careers: Questionnaire assessment of career preferences in medical school applicants and final-year students

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    BACKGROUND: The medical specialities chosen by doctors for their careers play an important part in the workforce planning of health-care services. However, there is little theoretical understanding of how different medical specialities are perceived or how choices are made, despite there being much work in general on this topic in occupational psychology, which is influenced by Holland's RIASEC (Realistic-Investigative-Artistic-Social-Enterprising-Conventional) typology of careers, and Gottfredson's model of circumscription and compromise. In this study, we use three large-scale cohorts of medical students to produce maps of medical careers. METHODS: Information on between 24 and 28 specialities was collected in three UK cohorts of medical students (1981, 1986 and 1991 entry), in applicants (1981 and 1986 cohorts, N = 1135 and 2032) or entrants (1991 cohort, N = 2973) and in final-year students (N = 330, 376, and 1437). Mapping used Individual Differences Scaling (INDSCAL) on sub-groups broken down by age and sex. The method was validated in a population sample using a full range of careers, and demonstrating that the RIASEC structure could be extracted. RESULTS: Medical specialities in each cohort, at application and in the final-year, were well represented by a two-dimensional space. The representations showed a close similarity to Holland's RIASEC typology, with the main orthogonal dimensions appearing similar to Prediger's derived orthogonal dimensions of 'Things-People' and 'Data-Ideas'. CONCLUSIONS: There are close parallels between Holland's general typology of careers, and the structure we have found in medical careers. Medical specialities typical of Holland's six RIASEC categories are Surgery (Realistic), Hospital Medicine (Investigative), Psychiatry (Artistic), Public Health (Social), Administrative Medicine (Enterprising), and Laboratory Medicine (Conventional). The homology between medical careers and RIASEC may mean that the map can be used as the basis for understanding career choice, and for providing career counselling
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