838 research outputs found

    Study of 42 and 85 GHz coupled cavity traveling-wave tubes for space use

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    Designs were formulated for four CW, millimeter wavelength traveling-wave tubes having high efficiency and long life. Three of these tubes, in the 42 to 44 GHz frequency region, develop power outputs of 100 to 300 watts with overall efficiencies of typically 45 percent. Another tube, which covers the frequency range of 84 to 86 GHz, provides a power output of 200 watts at 25 percent efficiency. The cathode current density in each design was 1A/sq cm. Each tube includes: metal-ceramic construction, periodic permanent magnet focusing, a two step velocity taper, an electron beam refocusing section, and a radiation cooled three-stage depressed collector. The electrical and mechanical design for each tube type is discussed in detail. The results of thermal and mechanical analyses are presented

    Resist, comply or workaround? An examination of different facets of user engagement with information systems

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    This paper provides a summary of studies of user resistance to Information Technology (IT) and identifies workaround activity as an understudied and distinct, but related, phenomenon. Previous categorizations of resistance have largely failed to address the relationships between the motivations for divergences from procedure and the associated workaround activity. This paper develops a composite model of resistance/workaround derived from two case study sites. We find four key antecedent conditions derived from both positive and negative resistance rationales and identify associations and links to various resultant workaround behaviours and provide supporting Chains of Evidence from two case studies

    Ethical issues in the use of in-depth interviews: literature review and discussion

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    This paper reports a literature review on the topic of ethical issues in in-depth interviews. The review returned three types of article: general discussion, issues in particular studies, and studies of interview-based research ethics. Whilst many of the issues discussed in these articles are generic to research ethics, such as confidentiality, they often had particular manifestations in this type of research. For example, privacy was a significant problem as interviews sometimes probe unexpected areas. For similar reasons, it is difficult to give full information of the nature of a particular interview at the outset, hence informed consent is problematic. Where a pair is interviewed (such as carer and cared-for) there are major difficulties in maintaining confidentiality and protecting privacy. The potential for interviews to harm participants emotionally is noted in some papers, although this is often set against potential therapeutic benefit. As well as these generic issues, there are some ethical issues fairly specific to in-depth interviews. The problem of dual role is noted in many papers. It can take many forms: an interviewer might be nurse and researcher, scientist and counsellor, or reporter and evangelist. There are other specific issues such as taking sides in an interview, and protecting vulnerable groups. Little specific study of the ethics of in-depth interviews has taken place. However, that which has shows some important findings. For example, one study shows participants are not averse to discussing painful issues provided they feel the study is worthwhile. Some papers make recommendations for researchers. One such is that they should consider using a model of continuous (or process) consent rather than viewing consent as occurring once, at signature, prior to the interview. However, there is a need for further study of this area, both philosophical and empirical

    Evaluation of the bacterial diversity of Pressure ulcers using bTEFAP pyrosequencing

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    <p>Abstract</p> <p>Background</p> <p>Decubitus ulcers, also known as bedsores or pressure ulcers, affect millions of hospitalized patients each year. The microflora of chronic wounds such as ulcers most commonly exist in the biofilm phenotype and have been known to significantly impair normal healing trajectories.</p> <p>Methods</p> <p>Bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP), a universal bacterial identification method, was used to identify bacterial populations in 49 decubitus ulcers. Diversity estimators were utilized and wound community compositions analyzed in relation to metadata such as Age, race, gender, and comorbidities.</p> <p>Results</p> <p>Decubitus ulcers are shown to be polymicrobial in nature with no single bacterium exclusively colonizing the wounds. The microbial community among such ulcers is highly variable. While there are between 3 and 10 primary populations in each wound there can be hundreds of different species present many of which are in trace amounts. There is no clearly significant differences in the microbial ecology of decubitus ulcer in relation to metadata except when considering diabetes. The microbial populations and composition in the decubitus ulcers of diabetics may be significantly different from the communities in non-diabetics.</p> <p>Conclusions</p> <p>Based upon the continued elucidation of chronic wound bioburdens as polymicrobial infections, it is recommended that, in addition to traditional biofilm-based wound care strategies, an antimicrobial/antibiofilm treatment program can be tailored to each patient's respective wound microflora.</p

    Questioning policy, youth participation and lifestyle sports

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    Young people have been identified as a key target group for whom participation in sport and physical activity could have important benefits to health and wellbeing and consequently have been the focus of several government policies to increase participation in the UK. Lifestyle sports represent one such strategy for encouraging and sustaining new engagements in sport and physical activity in youth groups, however, there is at present a lack of understanding of the use of these activities within policy contexts. This paper presents findings from a government initiative which sought to increase participation in sport for young people through provision of facilities for mountain biking in a forest in south-east England. Findings from qualitative research with 40 young people who participated in mountain biking at the case study location highlight the importance of non-traditional sports as a means to experience the natural environments through forms of consumption which are healthy, active and appeal to their identities. In addition, however, the paper raises questions over the accessibility of schemes for some individuals and social groups, and the ability to incorporate sports which are inherently participant-led into state-managed schemes. Lifestyle sports such as mountain biking involve distinct forms of participation which present a challenge for policy-makers who seek to create and maintain sustainable communities of youth participants

    Polymicrobial Nature of Chronic Diabetic Foot Ulcer Biofilm Infections Determined Using Bacterial Tag Encoded FLX Amplicon Pyrosequencing (bTEFAP)

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    Diabetic extremity ulcers are associated with chronic infections. Such ulcer infections are too often followed by amputation because there is little or no understanding of the ecology of such infections or how to control or eliminate this type of chronic infection. A primary impediment to the healing of chronic wounds is biofilm phenotype infections. Diabetic foot ulcers are the most common, disabling, and costly complications of diabetes. Here we seek to derive a better understanding of the polymicrobial nature of chronic diabetic extremity ulcer infections. spp. and against difficult to culture bacteria such as anaerobes. While PCR methods also have bias, further work is now needed in comparing traditional culture results to high-resolution molecular diagnostic methods such as bTEFAP

    The MINERν\nuA Data Acquisition System and Infrastructure

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    MINERν\nuA (Main INjector ExpeRiment ν\nu-A) is a new few-GeV neutrino cross section experiment that began taking data in the FNAL NuMI (Fermi National Accelerator Laboratory Neutrinos at the Main Injector) beam-line in March of 2010. MINERν\nuA employs a fine-grained scintillator detector capable of complete kinematic characterization of neutrino interactions. This paper describes the MINERν\nuA data acquisition system (DAQ) including the read-out electronics, software, and computing architecture.Comment: 34 pages, 16 figure

    Transitional experiences of post-16 sports education: Jack's story

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    This paper explores the layered transitional experiences of a semi-professional athlete named Jack (a pseudonym) between the fields of professional sport and further and higher education. Our analysis is framed by the quadripartite framework of structuration and focuses on Jack's 'in-situ' practices at his college and university in order to illustrate how these can operate to reproduce, transform, and challenge the habitual discourses and rituals that circulate within these institutions by generating forms of corporeal empowerment for young athletes who have valued conjunctural knowledge. The findings highlight the fragility of the transition process and raise questions regarding how the experiences of young people are shaped by the relationships between employment and post-16 education. Jack's experiences have implications for both policy and practice within further education and higher education. © 2012 © 2012 Taylor & Francis

    Perspectives on the ‘silent period’ for emergent bilinguals in England

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    This paper draws together the research findings from two ethnographic studies (Drury, 2007; Bligh, 2011) as a means to problematize the ‘silent period’ as experienced by young bilingual learners in two English speaking early years settings in England. Most teachers and senior early years practitioners in England are monolingual English speakers. The children (regardless of their mother tongue) are taught through the medium of spoken and written English in and through all subject areas. Bilingual learning through the mother tongue is not only disregarded in most schools in England but is actively discouraged in some. Three emergent bilingual learners were re-examined as case studies. Suki and Adyta (Bligh, 2011) of Japanese and Punjabi decent and Nazma (Drury, 2007) of Kashmiri descent were observed whilst they each negotiated new ways of knowing within and through an English pre-school setting. Sociocultural insights into how these young children employ their silenced mother tongue to negotiate their learning creates a fuller and richer portrait of the emergent bilingual learner both in and outside of preschool. These collaborative research findings present the silent period as agentive (Drury, 2007) and as a crucial time for self-mediated learning (Bligh, 2011) within the early years community of practice
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