2,776 research outputs found

    Conditioning of pulses from aerosol-particle detectors

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    Pulse-conditioner translates pulses generated by aerosol-particle detectors to a form acceptable by commercially available pulse height analyzers designed for nuclear-energy spectroscopy

    An Adaptation To Life In Acid Through A Novel Mevalonate Pathway.

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    Extreme acidophiles are capable of growth at pH values near zero. Sustaining life in acidic environments requires extensive adaptations of membranes, proton pumps, and DNA repair mechanisms. Here we describe an adaptation of a core biochemical pathway, the mevalonate pathway, in extreme acidophiles. Two previously known mevalonate pathways involve ATP dependent decarboxylation of either mevalonate 5-phosphate or mevalonate 5-pyrophosphate, in which a single enzyme carries out two essential steps: (1) phosphorylation of the mevalonate moiety at the 3-OH position and (2) subsequent decarboxylation. We now demonstrate that in extreme acidophiles, decarboxylation is carried out by two separate steps: previously identified enzymes generate mevalonate 3,5-bisphosphate and a new decarboxylase we describe here, mevalonate 3,5-bisphosphate decarboxylase, produces isopentenyl phosphate. Why use two enzymes in acidophiles when one enzyme provides both functionalities in all other organisms examined to date? We find that at low pH, the dual function enzyme, mevalonate 5-phosphate decarboxylase is unable to carry out the first phosphorylation step, yet retains its ability to perform decarboxylation. We therefore propose that extreme acidophiles had to replace the dual-purpose enzyme with two specialized enzymes to efficiently produce isoprenoids in extremely acidic environments

    Risk factors for chest infection in acute stroke: a prospective cohort study

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    <p><b>Background and Purpose:</b> Pneumonia is a major cause of morbidity and mortality after stroke. We aimed to determine key characteristics that would allow prediction of those patients who are at highest risk for poststroke pneumonia.</p> <p><b>Methods:</b> We studied a series of consecutive patients with acute stroke who were admitted to hospital. Detailed evaluation included the modified National Institutes of Health Stroke Scale; the Abbreviated Mental Test; and measures of swallow, respiratory, and oral health status. Pneumonia was diagnosed by set criteria. Patients were followed up at 3 months after stroke.</p> <p><b>Results:</b> We studied 412 patients, 391 (94.9%) with ischemic stroke and 21 (5.1%) with hemorrhagic stroke; 78 (18.9%) met the study criteria for pneumonia. Subjects who developed pneumonia were older (mean±SD age, 75.9±11.4 vs 64.9±13.9 years), had higher modified National Institutes of Health Stroke Scale scores, a history of chronic obstructive pulmonary disease, lower Abbreviated Mental Test scores, and a higher oral cavity score, and a greater proportion tested positive for bacterial cultures from oral swabs. In binary logistic-regression analysis, independent predictors (P<0.05) of pneumonia were age >65 years, dysarthria or no speech due to aphasia, a modified Rankin Scale score ≥4, an Abbreviated Mental Test score <8, and failure on the water swallow test. The presence of 2 or more of these risk factors carried 90.9% sensitivity and 75.6% specificity for the development of pneumonia.</p> <p><b>Conclusions:</b> Pneumonia after stroke is associated with older age, dysarthria/no speech due to aphasia, severity of poststroke disability, cognitive impairment, and an abnormal water swallow test result. Simple assessment of these variables could be used to identify patients at high risk of developing pneumonia after stroke.</p&gt

    Can we quantify harm in general practice records? An assessment of precision and power using computer simulation

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    <b>Background</b> Estimating harm rates for specific patient populations and detecting significant changes in them over time are essential if patient safety in general practice is to be improved. Clinical record review (CRR) is arguably the most suitable method for these purposes, but the optimal values and combinations of its parameters (such as numbers of records and practices) remain unknown. Our aims were to: 1. Determine and quantify CRR parameters; 2. Assess the precision and power of feasible CRR scenarios; and 3. Quantify the minimum requirements for adequate precision and acceptable power.<p></p> <b>Method</b> We explored precision and power of CRR scenarios using Monte Carlo simulation. A range of parameter values were combined in 864 different CRR scenarios, 1000 random data sets were generated for each, and harm rates were estimated and tested for change over time by fitting a generalised linear model with a Poisson response.<p></p> <b>Results</b> CRR scenarios with ≥100 detected harm incidents had harm rate estimates with acceptable precision. Harm reductions of 20% or ≥50% were detected with adequate power by those CRR scenarios with at least 100 and 500 harm incidents respectively. The number of detected harm incidents was dependent on the baseline harm rate multiplied by: the period of time reviewed in each record; number of records reviewed per practice; number of practices who reviewed records; and the number of times each record was reviewed.<p></p> <b>Conclusion</b> We developed a simple formula to calculate the minimum values of CRR parameters required to achieve adequate precision and acceptable power when monitoring harm rates. Our findings have practical implications for health care decision-makers, leaders and researchers aiming to measure and reduce harm at regional or national level

    Variation in health and social equity in the spaces where we live: A review of previous literature from the GeoHealth Laboratory

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    The previous decade has given rise to the importance of Geographic Information Systems (GIS) in explaining inequalities in health outcomes between groups based on their spatial location and social background. The GeoHealth Laboratory, based at the University of Canterbury, is a joint venture with the Health and Disability Intelligence unit within the Ministry of Health (MoH). The aims of this relationship are to add analytical capacity to MoH data collections and increase academic outputs of geospatial health research in New Zealand. GeoHealth research has often been a joint venture between Laboratory staff and students as well as collaboration with local and international researchers. These partnerships along with widely varied research interests have resulted in a large contribution of spatial health research in the field of health geography. This article reports on research undertaken by the GeoHealth Laboratory that has focused on access to neighbourhood determinants of health. An overview of key neighbourhoods and health research areas are outlined within the over-arching themes of indices of access to neighbourhood factors, access to undesireable neighbourhood destinations, health promoting neighbourhood factors, access to and utilisation of health services, and complementary data collection and research groups within New Zealand

    Effects of Wall Permittivity and Plasma Thickness on the Plasma Reflection Coefficient

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    Using video and multimodal classroom interaction analysis to investigate how information, misinformation, and disinformation influence pedagogy

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    Misinformation is accidentally wrong and disinformation is deliberately incorrect (i.e., deception). This paper uses the Pedagogy Analysis Framework (PAF) to investigate how information, misinformation, and disinformation influence classroom pedagogy. 95 people participated (i.e., one lesson with 7-year-olds, another with 10-year-olds, and three with a class of 13-year-olds). We used four video-based methods (lesson video analysis, teacher verbal protocols, pupil group verbal protocols, and teacher interviews). 35 hours of video data (recorded 2013-2020) were analysed using Grounded Theory Methods by the researchers, the class teachers, and groups of pupils (three girls and three boys). The methodology was Straussian Grounded Theory. We present how often participants used information, misinformation, and disinformation. We illustrate how the PAF helps understand and explain information, misinformation, and disinformation in the classroom by analysing video data transcripts. In addition, we discuss participant perceptions of the status of information; overlapping information, misinformation, and disinformation; and information communication difficulties
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