954 research outputs found

    Life Predicted in a Probabilistic Design Space for Brittle Materials With Transient Loads

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    Analytical techniques have progressively become more sophisticated, and now we can consider the probabilistic nature of the entire space of random input variables on the lifetime reliability of brittle structures. This was demonstrated with NASA s CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code combined with the commercially available ANSYS/Probabilistic Design System (ANSYS/PDS), a probabilistic analysis tool that is an integral part of the ANSYS finite-element analysis program. ANSYS/PDS allows probabilistic loads, component geometry, and material properties to be considered in the finite-element analysis. CARES/Life predicts the time dependent probability of failure of brittle material structures under generalized thermomechanical loading--such as that found in a turbine engine hot-section. Glenn researchers coupled ANSYS/PDS with CARES/Life to assess the effects of the stochastic variables of component geometry, loading, and material properties on the predicted life of the component for fully transient thermomechanical loading and cyclic loading

    New Developments in the SCIAMACHY Level 2 Ground Processor Towards Version 7

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    SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric ChartographY) aboard ESA’s environmental satellite ENVISAT observed the Earth’s atmosphere in limb, nadir, and solar/lunar occultation geometries covering the UV-Visible to NIR spectral range. It is a joint project of Germany, the Netherlands and Belgium and was launched in February 2002. SCIAMACHY doubled its originally planned in-orbit lifetime of five years before the communication to ENVISAT was severed in April 2012, and the mission entered its post-operational phase. In order to preserve the best quality of the outstanding data recorded by SCIAMACHY, data processors are still being updated. This presentation will highlight three new developments that are currently being incorporated into the forthcoming Version 7 of ESA’s operational Level 2 processor: 1. Tropospheric BrO, a new retrieval based on the scientific algorithm of (Theys et al., 2011). This algorithm had originally been developed for the GOME-2 sensor and was later adapted for SCIAMACHY. 2. Improved cloud flagging using limb measurements (Liebing, 2015). Limb cloud flags are already part of the SCIAMACHY L2 product. They are currently calculated employing the scientific algorithm developed by (Eichmann et al., 2015). Clouds are categorized into four types: water, ice, polar stratospheric and noctilucent clouds. High atmospheric aerosol loadings, however, often lead to spurious cloud flags, when aerosols had been misidentified as clouds. The new algorithm will better discriminate between aerosol and clouds. It will also have a higher sensitivity w.r.t. thin clouds. 3. A new, future-proof file format for the level 2 product based on NetCDF. The data format will be aligned and harmonized with other missions, particularly GOME and Sentinels. The final concept for the new format is still under discussion within the SCIAMACHY Quality Working Group

    Molecular characterization of Mycobacterium bovis strains isolated from cattle slaughtered at two abattoirs in Algeria

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    <p>Abstract</p> <p>Background</p> <p>Bovine Tuberculosis is prevalent in Algeria despite governmental attempts to control the disease. The objective of this study was to conduct, for the first time, molecular characterization of a population sample of <it>Mycobacterium bovis </it>strains isolated from slaughter cattle in Algeria. Between August and November 2007, 7250 animals were consecutively screened at the abattoirs of Algiers and Blida. In 260 animals, gross visible granulomatous lesions were detected and put into culture. Bacterial isolates were subsequently analysed by molecular methods.</p> <p>Results</p> <p>Altogether, 101 bacterial strains from 100 animals were subjected to molecular characterization. <it>M. bovis </it>was isolated from 88 animals. Other bacteria isolated included one strain of <it>M. caprae</it>, four <it>Rhodococcus equi </it>strains, three Non-tuberculous Mycobacteria (NTM) and five strains of other bacterial species. The <it>M. bovis </it>strains isolated showed 22 different spoligotype patterns; four of them had not been previously reported. The majority of <it>M. bovis </it>strains (89%) showed spoligotype patterns that were previously observed in strains from European cattle. Variable Number of Tandem Repeat (VNTR) typing supported a link between <it>M. bovis </it>strains from Algeria and France. One spoligotype pattern has also been shown to be frequent in <it>M. bovis </it>strains from Mali although the VNTR pattern of the Algerian strains differed from the Malian strains.</p> <p>Conclusion</p> <p><it>M. bovis </it>infections account for a high amount of granulomatous lesions detected in Algerian slaughter cattle during standard meat inspection at Algiers and Blida abattoir. Molecular typing results suggested a link between Algerian and European strains of <it>M. bovis</it>.</p

    Importance of late fall ENSO teleconnection in the Euro-Atlantic sector

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    Recent studies have indicated the importance of fall climate forcings and teleconnections in influencing the climate of the northern mid-to-high latitudes. Here, we present some exploratory analyses using observational data and seasonal hindcasts, with the aim of highlighting the potential of the El Niño-Southern Oscillation (ENSO) as a driver of climate variability during boreal late fall/early winter (November/December) in the North Atlantic-European sector and motivating further research on this relatively unexplored topic. The atmospheric ENSO teleconnection in November/December is reminiscent of the East Atlantic pattern and distinct from the well-known arching extratropical Rossby wavetrain found from January to March. Temperature and precipitation over Europe in November are positively correlated with the Niño3.4 index, which suggests a potentially important ENSO climate impact during late fall. In particular, the ENSO-related temperature anomaly extends over a much larger area than during the subsequent winter mont

    Muscarinic Inhibition of Calcium Current and M Current in Gα_q-Deficient Mice

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    Activation of M₁ muscarinic acetylcholine receptors (M₁ mAChR) inhibits M-type potassium currents (I_(K(M))) and N-type calcium currents (I_(Ca)) in mammalian sympathetic ganglia. Previous antisense experiments suggested that, in rat superior cervical ganglion (SCG) neurons, both effects were partly mediated by the G-protein Gα_q (Delmas et al., 1998a; Haley et al., 1998a), but did not eliminate a contribution by other pertussis toxin (PTX)-insensitive G-proteins. We have tested this further using mice deficient in the Gα_q gene. PTX-insensitive M₁ mAChR inhibition of I_(Ca) was strongly reduced in Gα_q −/− mouse SCG neurons and was fully restored by acute overexpression of Gα_q. In contrast, M₁mAChR inhibition of I_(K(M)) persisted in Gα_q−/− mouse SCG cells. However, unlike rat SCG neurons, muscarinic inhibition of I_(K(M)) was partly PTX-sensitive. Residual (PTX-insensitive)I_(K(M)) inhibition was slightly reduced in Gα_q −/− neurons, and the remaining response was then suppressed by anti-Gα_(q/11) antibodies. Bradykinin (BK) also inhibits IK(M) in rat SCG neurons via a PTX-insensitive G-protein (G_q and/or G₁₁; Jones et al., 1995). In mouse SCG neurons, I_(K(M)) inhibition by BK was fully PTX-resistant. It was unchanged in Gα_q −/− mice but was abolished by anti-Gα_(q/11) antibody. We conclude that, in mouse SCG neurons (1) M₁ mAChR inhibition of I_(Ca) is mediated principally by G_q, (2) M₁ mAChR inhibition of I_(K(M)) is mediated partly by G_q, more substantially by G₁₁, and partly by a PTX-sensitive G-protein(s), and (3) BK-induced inhibition of I_(K(M)) is mediated wholly by G₁₁

    Predictors of Hypertension in Mauritians with Normotension and Prehypertension at Baseline : A Cohort Study

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    Information on the predictors of future hypertension in Mauritians with prehypertension is scant. The aim of this study was to analyze the 5-year and 11-year risk of hypertension and its predictors in people with normotension and prehypertension at baseline in Mauritius in 1987. This was a retrospective cohort study of 883 men and 1194 women of Mauritian Indian and Mauritian Creole ethnicity, aged 25-74 years old, free of hypertension at baseline in 1987 with follow-up examinations in 1992 and 1998 using the same methodology. The main outcome was 5- and 11-year risk of hypertension. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were calculated. The 5-year risk of hypertension was 5.4-times higher in people with prehypertension compared with normotensive individuals at baseline. The corresponding odds for prehypertensive people at baseline regarding 11-year hypertension risk was 3.39 (95% CI 2.67-4.29) in the adjusted logistic regression models. Being of Creole ethnicity (OR 1.42; 95% CI 1.09-1.86) increased the 11-year odds of hypertension compared with the Indian population. It is of importance to screen for people with prehypertension and implement strategies to reduce their systolic blood pressure levels to the recommended levels of 120/80 mmHg. Special attention needs to be given to Mauritians of Creole ethnicity.Peer reviewe

    Needs-based planning for the oral health workforce - development and application of a simulation model

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    Background: The World Health Organization’s global strategy on human resources for health includes an objective to align investment in human resources for health with the current and future needs of the population. Although oral health is a key indicator of overall health and wellbeing, and oral diseases are the most common noncommunicable diseases affecting half the world’s population, oral health workforce planning efforts have been limited to simplistic target dentist-population or constant services-population ratios which do not account for levels of and changes in population need. Against this backdrop, our aim was to develop and operationalise an oral health needs-based workforce planning simulation tool. Methods: Using a conceptual framework put forward in the literature, we aimed to build the model in Microsoft Excel and apply it in a hypothetical context to demonstrate its operability. The model incorporates a provider supply component and a provider requirement component, enabling a comparison of the current and future supply of and requirement for oral health workers. Publicly available data, including the Special Eurobarometer 330 Oral Health Survey, were used to populate the model. Assumptions were made where data were not publicly available and key assumptions were tested in scenario analyses. Results: We have systematically developed a needs-based workforce planning model for the oral health workforce and applied the model in a hypothetical context over a 30-year time span. In the 2017 baseline scenario, the model produced a full-time equivalent (FTE) provider requirement figure of 899 dentists compared with an FTE provider supply figure of 1985. In the scenario analyses, the FTE provider requirement figure ranged from 1123 to 1629 illustrating the extent of the impact of changing parameter values. Conclusions: In response to policy makers’ recognition of the pressing need to better plan human resources for health and the scarcity of work in this area for dentistry, we have demonstrated the feasibility of producing a workable, practical and useful needs-based workforce planning simulation tool for the oral health workforce. In doing so, we have highlighted the challenges faced in accessing timely and relevant data needed to populate such models and ensure the reliability of model outputs

    α1-Antitrypsin deficiency.

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    α1-Antitrypsin deficiency (A1ATD) is an inherited disorder caused by mutations in SERPINA1, leading to liver and lung disease. It is not a rare disorder but frequently goes underdiagnosed or misdiagnosed as asthma, chronic obstructive pulmonary disease (COPD) or cryptogenic liver disease. The most frequent disease-associated mutations include the S allele and the Z allele of SERPINA1, which lead to the accumulation of misfolded α1-antitrypsin in hepatocytes, endoplasmic reticulum stress, low circulating levels of α1-antitrypsin and liver disease. Currently, there is no cure for severe liver disease and the only management option is liver transplantation when liver failure is life-threatening. A1ATD-associated lung disease predominately occurs in adults and is caused principally by inadequate protease inhibition. Treatment of A1ATD-associated lung disease includes standard therapies that are also used for the treatment of COPD, in addition to the use of augmentation therapy (that is, infusions of human plasma-derived, purified α1-antitrypsin). New therapies that target the misfolded α1-antitrypsin or attempt to correct the underlying genetic mutation are currently under development

    Probabilistic Prediction of Lifetimes of Ceramic Parts

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    ANSYS/CARES/PDS is a software system that combines the ANSYS Probabilistic Design System (PDS) software with a modified version of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) Version 6.0 software. [A prior version of CARES/Life was reported in Program for Evaluation of Reliability of Ceramic Parts (LEW-16018), NASA Tech Briefs, Vol. 20, No. 3 (March 1996), page 28.] CARES/Life models effects of stochastic strength, slow crack growth, and stress distribution on the overall reliability of a ceramic component. The essence of the enhancement in CARES/Life 6.0 is the capability to predict the probability of failure using results from transient finite-element analysis. ANSYS PDS models the effects of uncertainty in material properties, dimensions, and loading on the stress distribution and deformation. ANSYS/CARES/PDS accounts for the effects of probabilistic strength, probabilistic loads, probabilistic material properties, and probabilistic tolerances on the lifetime and reliability of the component. Even failure probability becomes a stochastic quantity that can be tracked as a response variable. ANSYS/CARES/PDS enables tracking of all stochastic quantities in the design space, thereby enabling more precise probabilistic prediction of lifetimes of ceramic components
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