161 research outputs found

    Participant Observation as Ethnography or Ethnography as Participant Observation in Organizational Research

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    There is a strong tradition of observational research in most areas of the social sciences, especially in Anthropology and Sociology. However, in business and management research observation is often seen as a poor relative to questionnaire surveys and qualitative interviewing. This chapter discusses the use of observational techniques especially for less experienced researchers planning their first major investigation, exploring the difference between participant and non-participant approaches, different techniques of data collection, recording and analysis. Rather than seeking to provide a full guide to conducting participant observation, an impractical task in a single chapter, this offering discusses some of the key issues facing researchers in Business and Management who choose to conduct this sort of research, exploring different approaches to participant observation and some of the ethical and practical challenges associated with the collection and analysis of observational data. The chapter draws on the author’s experience of conducting participant observation in organizations with examples of both employee (Sandiford and Seymour, 2002; Seymour and Sandiford, 2013) and customer perspectives (Sandiford and Divers, 2011). It will also draw from ‘classic’ observational studies such as Mars and Nicod (1984) and more recent examples such as Watson and Watson (2012).Peter John Sandifor

    A systematic review of Vancouver B2 and B3 periprosthetic femoral fractures

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    Aims The aim of this study was to investigate the outcomes of Vancouver type B2 and B3 fractures by performing a systematic review of the methods of surgical treatment which have been reported. Materials and Methods A systematic search was performed in Ovid MEDLINE, Embase and the Cochrane Central Register of Controlled Trials. For inclusion, studies required a minimum of ten patients with a Vancouver type B2 and/or ten patients with a Vancouver type B3 fracture, a minimum mean follow-up of two years and outcomes which were matched to the type of fracture. Studies were also required to report the rate of re-operation as an outcome measure. The protocol was registered in the PROSPERO database. Results A total of 22 studies were included based on the eligibility criteria, including 343 B2 fractures and 167 B3 fractures. The mean follow-up ranged from 32 months to 74 months. Of 343 Vancouver B2 fractures, the treatment in 298 (86.8%) involved revision arthroplasty and 45 (12.6%) were treated with internal fixation alone. A total of 37 patients (12.4%) treated with revision arthroplasty and six (13.3%) treated by internal fixation only underwent further re-operation. Of 167 Vancouver B3 fractures, the treatment in 160 (95.8%) involved revision arthroplasty and eight (4.8%) were treated with internal fixation without revision. A total of 23 patients (14.4%) treated with revision arthroplasty and two (28.6%) treated only with internal fixation required re-operation. Conclusion A significant proportion, particularly of B2 fractures, were treated without revision of the stem. These were associated with a higher rate of re-operation. The treatment of B3 fractures without revision of the stem resulted in a high rate of re-operation. This demonstrates the importance of careful evaluation and accurate characterisation of the fracture at the time of presentation to ensure the correct management. There is a need for improvement in the reporting of data in case series recording the outcome of the surgical treatment of periprosthetic fractures. We have suggested a minimum dataset to improve the quality of data in studies dealing with these fractures

    Effect of acute hypoxia on respiratory muscle fatigue in healthy humans

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    <p>Abstract</p> <p>Background</p> <p>Greater diaphragm fatigue has been reported after hypoxic versus normoxic exercise, but whether this is due to increased ventilation and therefore work of breathing or reduced blood oxygenation per se remains unclear. Hence, we assessed the effect of different blood oxygenation level on isolated hyperpnoea-induced inspiratory and expiratory muscle fatigue.</p> <p>Methods</p> <p>Twelve healthy males performed three 15-min isocapnic hyperpnoea tests (85% of maximum voluntary ventilation with controlled breathing pattern) in normoxic, hypoxic (SpO<sub>2 </sub>= 80%) and hyperoxic (FiO<sub>2 </sub>= 0.60) conditions, in a random order. Before, immediately after and 30 min after hyperpnoea, transdiaphragmatic pressure (P<sub>di,tw </sub>) was measured during cervical magnetic stimulation to assess diaphragm contractility, and gastric pressure (P<sub>ga,tw </sub>) was measured during thoracic magnetic stimulation to assess abdominal muscle contractility. Two-way analysis of variance (time x condition) was used to compare hyperpnoea-induced respiratory muscle fatigue between conditions.</p> <p>Results</p> <p>Hypoxia enhanced hyperpnoea-induced P<sub>di,tw </sub>and P<sub>ga,tw </sub>reductions both immediately after hyperpnoea (P<sub>di,tw </sub>: normoxia -22 ± 7% vs hypoxia -34 ± 8% vs hyperoxia -21 ± 8%; P<sub>ga,tw </sub>: normoxia -17 ± 7% vs hypoxia -26 ± 10% vs hyperoxia -16 ± 11%; all <it>P </it>< 0.05) and after 30 min of recovery (P<sub>di,tw </sub>: normoxia -10 ± 7% vs hypoxia -16 ± 8% vs hyperoxia -8 ± 7%; P<sub>ga,tw </sub>: normoxia -13 ± 6% vs hypoxia -21 ± 9% vs hyperoxia -12 ± 12%; all <it>P </it>< 0.05). No significant difference in P<sub>di,tw </sub>or P<sub>ga,tw </sub>reductions was observed between normoxic and hyperoxic conditions. Also, heart rate and blood lactate concentration during hyperpnoea were higher in hypoxia compared to normoxia and hyperoxia.</p> <p>Conclusions</p> <p>These results demonstrate that hypoxia exacerbates both diaphragm and abdominal muscle fatigability. These results emphasize the potential role of respiratory muscle fatigue in exercise performance limitation under conditions coupling increased work of breathing and reduced O<sub>2 </sub>transport as during exercise in altitude or in hypoxemic patients.</p

    Genetic Ablation of Pannexin1 Protects Retinal Neurons from Ischemic Injury

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    Pannexin1 (Panx1) forms large nonselective membrane channel that is implicated in paracrine and inflammatory signaling. In vitro experiments suggested that Panx1 could play a key role in ischemic death of hippocampal neurons. Since retinal ganglion cells (RGCs) express high levels of Panx1 and are susceptible to ischemic induced injury, we hypothesized that Panx1 contributes to rapid and selective loss of these neurons in ischemia. To test this hypothesis, we induced experimental retinal ischemia followed by reperfusion in live animals with the Panx1 channel genetically ablated either in the entire mouse (Panx1 KO), or only in neurons using the conditional knockout (Panx1 CKO) technology. Here we report that two distinct neurotoxic processes are induced in RGCs by ischemia in the wild type mice but are inactivated in Panx1KO and Panx1 CKO animals. First, the post-ischemic permeation of RGC plasma membranes is suppressed, as assessed by dye transfer and calcium imaging assays ex vivo and in vitro. Second, the inflammasome-mediated activation of caspase-1 and the production of interleukin-1β in the Panx1 KO retinas are inhibited. Our findings indicate that post-ischemic neurotoxicity in the retina is mediated by previously uncharacterized pathways, which involve neuronal Panx1 and are intrinsic to RGCs. Thus, our work presents the in vivo evidence for neurotoxicity elicited by neuronal Panx1, and identifies this channel as a new therapeutic target in ischemic pathologies

    The cytoskeleton in cell-autonomous immunity: structural determinants of host defence

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    Host cells use antimicrobial proteins, pathogen-restrictive compartmentalization and cell death in their defence against intracellular pathogens. Recent work has revealed that four components of the cytoskeleton — actin, microtubules, intermediate filaments and septins, which are well known for their roles in cell division, shape and movement — have important functions in innate immunity and cellular self-defence. Investigations using cellular and animal models have shown that these cytoskeletal proteins are crucial for sensing bacteria and for mobilizing effector mechanisms to eliminate them. In this Review, we highlight the emerging roles of the cytoskeleton as a structural determinant of cell-autonomous host defence

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

    The evolution of epigean and stygobitic species of Koonunga Sayce, 1907 (Syncarida: Anaspidacea) in Southern Australia, with the description of three new species

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    Three new species of Koonunga were discovered in surface and subterranean waters in southern Australia, and were defined using mtDNA analyses and morphology. The new species are: Koonunga hornei Leijs & King; K. tatiaraensis Leijs & King and K. allambiensis Leijs & King. Molecular clock analyses indicate that the divergence times of the species are older than the landscape that they currently inhabit. Different scenarios explaining this apparent discrepancy are discussed in the context of the palaeography of the area. A freshwater epigean origin for Koonunga is considered the most likely hypothesis, whereby some lineages made the transition to the subterranean environment within the last few million years influenced by significant climatic cooling/drying. We discuss the possibility that one stygobitic lineage secondarily regained some of its body pigmentation as adaptation to increased photic conditions after cave collapse and forming of cenotes during the last glacial maximum.Remko Leijs, Tessa Bradford, James G. Mitchell, William F. Humphreys, Steven J. B. Cooper, Peter Goonan, Rachael A. Kin
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