1,964 research outputs found

    The microbiological quality of rainwater used for toilet flushing, cleaning and watering the garden- pilot study 2005

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    Regenwater opgevangen in reservoirs en toegepast voor onder andere toiletspoeling is vaak fecaal verontreinigd en bevat soms ziekteverwekkende bacterien. Om het infectierisico bij toepassing van dit water te kunnen schatten is aanvullend onderzoek nodig waarbij ziekteverwekkers worden gekwantificeerd en getypeerd en waarbij onderzocht wordt in welke mate gebruikers worden blootgesteld aan het besmette water.Regenwater is aanvankelijk onbesmet, maar bij afstromen langs oppervlakken en tijdens opslag in reservoirs kan besmetting optreden met micro-organismen die ziekte bij de mens kunnen veroorzaken. Dit kan gebeuren wanneer bijvoorbeeld vogelfeces van het dak wordt gespoeld of ratten of andere dieren toegang hebben tot het reservoir of open leidingen. Onderzoek van opgevangen hemelwater op vier verschillende locaties in Nederland toonde de aanwezigheid van de indicatoren voor fecale verontreiniging, bacterien van de coligroep, E. coli en enterococcen, in respectievelijk 28, 27 en 27 van de 28 onderzochte monsters aan. De potentieel ziekteverwekkende bacterien Campylobacter en Legionella pneumophila werden elk een maal op een locatie aangetroffen. Aeromonas en Clostridium perfringens, die ook ziekte bij de mens kunnen veroorzaken, werden in respectievelijk 20 en 23 van de 28 monsters gevonden. Salmonella en Vibrio werden op geen van de locaties aangetroffen. De aanwezigheid van ziekteverwekkende micro-organismen in regenwater toegepast voor toiletspoeling kan negatieve gevolgen voor de volksgezondheid hebben. Op basis van de verkregen resultaten is het nog niet mogelijk om het risico op het oplopen van een infectie bij blootstelling aan dit water te schatten omdat daarvoor nog aanvullende typerings- en blootstellingsgegevens nodig zijn.Rainwater collected in reservoirs and used for toilet flushing, for example, is often fecally contaminated and sometimes contains pathogenic bacteria. Estimating risk of infection caused by use of this water, will require additional research for enumerating and typing pathogens and for determining exposure to the contaminated water. Rainwater at the source is not contaminated with potential human pathogenic micro-organisms, but may become so at surface run-off and during storage in containers. This may occur when bird faeces runs off roofs, or rats or other animals have access to rainwater reservoirs or open mains. Examination of collected rainwater at four different sites in the Netherlands showed the presence of faecal indicator bacteria as total coliforms, E. coli and intestinal enterococci in 28, 27 and 27, respectively, of the 28 samples examined. Each of the potential human pathogenic bacteria, Campylobacter and Legionella pneumophila, was detected once at one sampling site. Aeromonas and Clostridium perfringens, which may also cause disease in humans, were detected in 20 and 23 of the 28 tested samples, respectively. Salmonella and Vibrio were not detected in any of the samples. The presence of potential pathogenic micro-organisms in rainwater used for toilet flushing may have adverse health effects. However, on the basis of the above results, and because additional typing and exposure data are required, it is not yet possible to estimate the risk of infection at exposure to this water.VROM Inspecti

    The microbiological quality of rainwater used for toilet flushing, cleaning and watering the garden- pilot study 2005

    Get PDF
    Rainwater collected in reservoirs and used for toilet flushing, for example, is often fecally contaminated and sometimes contains pathogenic bacteria. Estimating risk of infection caused by use of this water, will require additional research for enumerating and typing pathogens and for determining exposure to the contaminated water. Rainwater at the source is not contaminated with potential human pathogenic micro-organisms, but may become so at surface run-off and during storage in containers. This may occur when bird faeces runs off roofs, or rats or other animals have access to rainwater reservoirs or open mains. Examination of collected rainwater at four different sites in the Netherlands showed the presence of faecal indicator bacteria as total coliforms, E. coli and intestinal enterococci in 28, 27 and 27, respectively, of the 28 samples examined. Each of the potential human pathogenic bacteria, Campylobacter and Legionella pneumophila, was detected once at one sampling site. Aeromonas and Clostridium perfringens, which may also cause disease in humans, were detected in 20 and 23 of the 28 tested samples, respectively. Salmonella and Vibrio were not detected in any of the samples. The presence of potential pathogenic micro-organisms in rainwater used for toilet flushing may have adverse health effects. However, on the basis of the above results, and because additional typing and exposure data are required, it is not yet possible to estimate the risk of infection at exposure to this water.Regenwater opgevangen in reservoirs en toegepast voor onder andere toiletspoeling is vaak fecaal verontreinigd en bevat soms ziekteverwekkende bacterien. Om het infectierisico bij toepassing van dit water te kunnen schatten is aanvullend onderzoek nodig waarbij ziekteverwekkers worden gekwantificeerd en getypeerd en waarbij onderzocht wordt in welke mate gebruikers worden blootgesteld aan het besmette water.Regenwater is aanvankelijk onbesmet, maar bij afstromen langs oppervlakken en tijdens opslag in reservoirs kan besmetting optreden met micro-organismen die ziekte bij de mens kunnen veroorzaken. Dit kan gebeuren wanneer bijvoorbeeld vogelfeces van het dak wordt gespoeld of ratten of andere dieren toegang hebben tot het reservoir of open leidingen. Onderzoek van opgevangen hemelwater op vier verschillende locaties in Nederland toonde de aanwezigheid van de indicatoren voor fecale verontreiniging, bacterien van de coligroep, E. coli en enterococcen, in respectievelijk 28, 27 en 27 van de 28 onderzochte monsters aan. De potentieel ziekteverwekkende bacterien Campylobacter en Legionella pneumophila werden elk een maal op een locatie aangetroffen. Aeromonas en Clostridium perfringens, die ook ziekte bij de mens kunnen veroorzaken, werden in respectievelijk 20 en 23 van de 28 monsters gevonden. Salmonella en Vibrio werden op geen van de locaties aangetroffen. De aanwezigheid van ziekteverwekkende micro-organismen in regenwater toegepast voor toiletspoeling kan negatieve gevolgen voor de volksgezondheid hebben. Op basis van de verkregen resultaten is het nog niet mogelijk om het risico op het oplopen van een infectie bij blootstelling aan dit water te schatten omdat daarvoor nog aanvullende typerings- en blootstellingsgegevens nodig zijn

    Optical Scattering Measurements of Laser Induced Damage in the Intraocular Lens

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    This study optically determines whether the amount of light scatter due to laser-induced damage to the intraocular lens (IOL) is significant in relation to normal straylight values in the human eye. Two IOLs with laser-induced damage were extracted from two donor eyes. Each IOL had 15 pits and/or cracks. The surface area of each pit was measured using a microscope. For 6 pits per intraocular lens the point spread function (PSF) in terms of straylight was measured and the total straylight for all 15 pits was estimated. The damage in the IOLs was scored as mild/moderate. The total damaged surface areas, for a 3.5 mm pupil, in the two IOLs were 0.13% (0.0127 mm2) and 0.66% (0.064 mm2), respectively. The angular dependence of the straylight caused by the damage was similar to that of the normal PSF. The total average contribution to straylight was log(s) = −0.82 and −0.42, much less than the straylight value of the normal eye

    Probabilistic Computation in Human Perception under Variability in Encoding Precision

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    A key function of the brain is to interpret noisy sensory information. To do so optimally, observers must, in many tasks, take into account knowledge of the precision with which stimuli are encoded. In an orientation change detection task, we find that encoding precision does not only depend on an experimentally controlled reliability parameter (shape), but also exhibits additional variability. In spite of variability in precision, human subjects seem to take into account precision near-optimally on a trial-to-trial and item-to-item basis. Our results offer a new conceptualization of the encoding of sensory information and highlight the brain’s remarkable ability to incorporate knowledge of uncertainty during complex perceptual decision-making

    Are physical symptoms among survivors of a disaster presented to the general practitioner? A comparison between self-reports and GP data

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    <p>Abstract</p> <p>Background</p> <p>Most studies examining medically unexplained symptoms (MUS) have been performed in primary or secondary care and have examined symptoms for which patients sought medical attention. Disasters are often described as precipitating factors for MUS. However, health consequences of disasters are typically measured by means of questionnaires, and it is not known whether these self-reported physical symptoms are presented to the GP. It is also not known if the self-reported symptoms are related to a medical disorder or if they remain medically unexplained. In the present study, three research questions were addressed. Firstly, were self-reported symptoms among survivors presented to the GP? Secondly, were the symptoms presented to the GP associated with a high level of functional impairment and distress? Thirdly, what was the GP's clinical judgment of the presented symptoms, i.e. were the symptoms related to a medical diagnosis or could they be labeled MUS?</p> <p>Methods</p> <p>Survivors of a man-made disaster (N = 887) completed a questionnaire 3 weeks (T1) and 18 months (T2) post-disaster. This longitudinal health survey was combined with an ongoing surveillance program of health problems registered by GPs.</p> <p>Results</p> <p>The majority of self-reported symptoms was not presented to the GP and survivors were most likely to present persistent symptoms to the GP. For example, survivors with stomachache at both T1 and T2 were more likely to report stomachache to their GP (28%) than survivors with stomachache at only T1 (6%) or only T2 (13%). Presentation of individual symptoms to the GP was not consistently associated with functional impairment and distress. 56 – 91% of symptoms were labeled as MUS after clinical examination.</p> <p>Conclusion</p> <p>These results indicate that the majority of self-reported symptoms among survivors of a disaster are not presented to the GP and that the decision to consult with a GP for an individual symptom is not dependent on the level of impairment and distress. Also, self-reported physical symptoms such as headache, back pain and shortness of breath are likely to remain medically unexplained after the clinical judgment of a GP.</p

    Studying technology use as social practice: the untapped potential of ethnography

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    Information and communications technologies (ICTs) in healthcare are often introduced with expectations of higher-quality, more efficient, and safer care. Many fail to meet these expectations. We argue here that the well-documented failures of ICTs in healthcare are partly attributable to the philosophical foundations of much health informatics research. Positivistic assumptions underpinning the design, implementation and evaluation of ICTs (in particular the notion that technology X has an impact which can be measured and reproduced in new settings), and the deterministic experimental and quasi-experimental study designs which follow from these assumptions, have inherent limitations when ICTs are part of complex social practices involving multiple human actors. We suggest that while experimental and quasi-experimental studies have an important place in health informatics research overall, ethnography is the preferred methodological approach for studying ICTs introduced into complex social systems. But for ethnographic approaches to be accepted and used to their full potential, many in the health informatics community will need to revisit their philosophical assumptions about what counts as research rigor

    The role of input noise in transcriptional regulation

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    Even under constant external conditions, the expression levels of genes fluctuate. Much emphasis has been placed on the components of this noise that are due to randomness in transcription and translation; here we analyze the role of noise associated with the inputs to transcriptional regulation, the random arrival and binding of transcription factors to their target sites along the genome. This noise sets a fundamental physical limit to the reliability of genetic control, and has clear signatures, but we show that these are easily obscured by experimental limitations and even by conventional methods for plotting the variance vs. mean expression level. We argue that simple, global models of noise dominated by transcription and translation are inconsistent with the embedding of gene expression in a network of regulatory interactions. Analysis of recent experiments on transcriptional control in the early Drosophila embryo shows that these results are quantitatively consistent with the predicted signatures of input noise, and we discuss the experiments needed to test the importance of input noise more generally.Comment: 11 pages, 5 figures minor correction

    Diabetes causes marked inhibition of mitochondrial metabolism in pancreatic β-cells

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    Diabetes is a global health problem caused primarily by the inability of pancreatic β-cells to secrete adequate levels of insulin. The molecular mechanisms underlying the progressive failure of β-cells to respond to glucose in type-2 diabetes remain unresolved. Using a combination of transcriptomics and proteomics, we find significant dysregulation of major metabolic pathways in islets of diabetic βV59M mice, a non-obese, eulipidaemic diabetes model. Multiple genes/proteins involved in glycolysis/gluconeogenesis are upregulated, whereas those involved in oxidative phosphorylation are downregulated. In isolated islets, glucose-induced increases in NADH and ATP are impaired and both oxidative and glycolytic glucose metabolism are reduced. INS-1 β-cells cultured chronically at high glucose show similar changes in protein expression and reduced glucose-stimulated oxygen consumption: targeted metabolomics reveals impaired metabolism. These data indicate hyperglycaemia induces metabolic changes in β-cells that markedly reduce mitochondrial metabolism and ATP synthesis. We propose this underlies the progressive failure of β-cells in diabetes.Peer reviewe
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