3,864 research outputs found

    Fluid flow analysis by a modified, white light, Lau interferometer

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    This paper presents a sharp focussing schlieren system based upon a modified Lau interferometer. A method of reducing the depth of focus of the system is demonstrated and the development of the system to study large fields of view by theincorporation of flexible membrane mirrors is discussed

    The Bracero Program Applied to Immigration Today

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    Microarray analysis of whole genome expression of intracellular Mycobacterium tuberculosis

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    Analysis of the changing mRNA expression profile of Mycobacterium tuberculosis though the course of infection promises to advance our understanding of how mycobacteria are able to survive the host immune response. The difficulties of sample extraction from distinct mycobacterial populations, and of measuring mRNA expression profiles of multiple genes has limited the impact of gene expression studies on our interpretation of this dynamic infection process. The development of whole genome microarray technology together with advances in sample collection have allowed the expression pattern of the whole M. tuberculosis genome to be compared across a number of different in vitro conditions, murine and human tissue culture models and in vivo infection samples. This review attempts to produce a summative model of the M. tuberculosis response to infection derived from or reflected in these gene expression datasets. The mycobacterial response to the intracellular environment is characterised by the utilisation of lipids as a carbon source and the switch from aerobic/microaerophilic to anaerobic respiratory pathways. Other genes induced in the macrophage phagosome include those likely to be involved in the maintenance of the cell wall and genes related to DNA damage, heat shock, iron sequestration and nutrient limitation. The comparison of transcriptional data from in vitro models of infection with complex in vivo samples, together with the use of bacterial RNA amplification strategies to sample defined populations of bacilli, should allow us to make conclusions about M. tuberculosis physiology and host microenvironments during natural infection

    Fit for work? Health, employability and challenges for the UK welfare reform agenda

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    This article introduces a special issue of Policy Studies entitled ā€œFit for work? Health, employability and challenges for the UK welfare reform agendaā€. Growing from a shared concern over the need to expand the evidence base around the processes that led to large numbers of people claiming disability benefits in the UK, it brings together contributions from leading labour market and social policy researchers providing evidence and commentary on major reforms to Incapacity Benefit (IB) in the UK. This special issue address three key questions: what are the main causes of the long-term rise in the number of people claiming IBs; what will reduce the number of claimants; and what is likely to deliver policy effectively and efficiently? This introduction first explains and examines the challenges to reforms to IB in the UK, and then, in conclusion, highlights the answers to the previous three questions ā€“ first, labour market restructuring and marginalisation have driven the rise in numbers claiming IBs. Second, economic regeneration in the Britainā€™s less prosperous areas coupled with intensive and sustained supply-side support measures will bring numbers down. Third, delivery need to be flexible and tailored to individual needs and needs to be able to access local and expert knowledge in a range of organisations, including Job Centre Plus, the NHS as well as the private and voluntary sectors

    Life Experiences of Black Student-Athletes in Revenue-Producing Sports: A Descriptive Empirical Analysis

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    Recent NCAA reform (Propositions 48 and 42) have made imperative a better understanding of the social and psychological factor affecting black student-athletes in revenue-producing sports. This study focused on the college experience of black student-athletes at 42 NCAA Division I schools in comparison to white student-athletes and other black college students in four areas: demographic and academic background; college life experience; mental health; and social support. Black student-athletes differed from both comparison groups across all four topic areas. Results of the comparison were discissed, and policy recommendations were presented. The present study examined data from a national representative sample of full-time undergraduate student-athletes at Division I institutions commissioned by the Presidents Commission of the NCAA. Forty-two of the 291 Division I institutions for 1987-1988 were randomly selected to participate. lnstitutions were relatively evenly distributed across the NCAA's geographic districts and regions and were representative on a variety of indicators of institutional and student body characteristics, as well as sports history and involvement. A total of 5123 student-athletes and students was sampled. This study focused on three subgroups within the sample: black student-athletes participating in revenue-producing sports n=847); white student-athletes participating in revenue-producing sports (n=1161); and a random sample of black students who were not members of an athletic team (n=511). The participants' informed consent was obtained. Questionnaires were administered in group of four or five students, with at least one data collector present. They had four categories: demographic and academic background, college life experiences, mental health status, and social support. Results suggested that black student-athletes enter the university with very different educational and socio-cultural backgrounds than both white student-athletes and other black students. Black student-athletes have significantly lower family income and less educated parents. Greater differences erre found when comparing black student-athletes with other black students than with white student-athletes. Black and white student-athletes do not differ in the importance they ascribe to earning a degree, their satisfaction in their relationship with coaches, and their overall satisfaction with life

    The influence of 'significant others' on persistent back pain and work participation: a qualitative exploration of illness perceptions

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    Background Individual illness perceptions have been highlighted as important influences on clinical outcomes for back pain. However, the illness perceptions of 'significant others' (spouse/partner/close family member) are rarely explored, particularly in relation to persistent back pain and work participation. The aim of this study was to initiate qualitative research in this area in order to further understand these wider influences on outcome. Methods Semi-structured interviews based on the chronic pain version of the Illness Perceptions Questionnaire-Revised were conducted with a convenience sample of UK disability benefit claimants, along with their significant others (n=5 dyads). Data were analysed using template analysis. Results Significant others shared, and perhaps further reinforced, claimants' unhelpful illness beliefs including fear of pain/re-injury associated with certain types of work and activity, and pessimism about the likelihood of return to work. In some cases, significant others appeared more resigned to the permanence and negative inevitable consequences of the claimant's back pain condition on work participation, and were more sceptical about the availability of suitable work and sympathy from employers. In their pursuit of authenticity, claimants were keen to stress their desire to work whilst emphasising how the severity and physical limitations of their condition prevented them from doing so. In this vein, and seemingly based on their perceptions of what makes a 'good' significant other, significant others acted as a 'witness to pain', supporting claimants' self-limiting behaviour and statements of incapacity, often responding with empathy and assistance. The beliefs and responses of significant others may also have been influenced by their own experience of chronic illness, thus participants lives were often intertwined and defined by illness. Conclusions The findings from this exploratory study reveal how others and wider social circumstances might contribute both to the propensity of persistent back pain and to its consequences. This is an area that has received little attention to date, and wider support of these findings may usefully inform the design of future intervention programmes aimed at restoring work participation

    The frequency and properties of young tidal dwarf galaxies in nearby gas-rich groups

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    We present high-resolution Giant Metrewave Radio Telescope (GMRT) HI observations and deep Canada-France-Hawaii Telescope (CFHT) optical imaging of two galaxy groups: NGC 4725/47 and NGC 3166/9. These data are part of a multi-wavelength unbiased survey of the gas-rich dwarf galaxy populations in three nearby interacting galaxy groups. The NGC 4725/47 group hosts two tidal knots and one dIrr. Both tidal knots are located within a prominent HI tidal tail, appear to have sufficient mass (M_gas~10^8 M_sol) to evolve into long-lived tidal dwarf galaxies (TDGs) and are fairly young in age. The NGC 3166/9 group contains a TDG candidate, AGC 208457, at least three dIrrs and four HI knots. Deep CFHT imaging confirms that the optical component of AGC 208457 is bluer -- with a 0.28 mag g-r colour -- and a few Gyr younger than its purported parent galaxies. Combining the results for these groups with those from the NGC 871/6/7 group reported earlier, we find that the HI properties, estimated stellar ages and baryonic content of the gas-rich dwarfs clearly distinguish tidal features from their classical counterparts. We optimistically identify four potentially long-lived tidal objects associated to three separate pairs of interacting galaxies, implying that TDGs are not readily produced during interaction events as suggested by some recent simulations. The tidal objects examined in this survey also appear to have a wider variety of properties than TDGs of similar mass formed in current simulations of interacting galaxies, which could be the result of pre- or post-formation environmental influences.Comment: 18 pages, 14 figures, accepted for publication in MNRA
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