732 research outputs found

    Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

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    The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

    Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

    Full text link
    The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

    Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

    Full text link
    The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

    Telemedicine Improves Performance of a Two-Incision Lower Leg Fasciotomy by Combat Medics:A Randomized Controlled Trial

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    Introduction:The primary aim of this randomized controlled trial was to assess if a head-mounted display (HMD) providing telemedicine support improves performance of a two-incision lower leg fasciotomy by a NATO special operations combat medic (combat medic).Materials and Methods:Thirty-six combat medics were randomized into two groups: One group performed a two-incision lower leg fasciotomy with the assistance of an HMD, while the control group completed the procedure without guidance. A Mann-Whitney U test was used to determine the possible differences in release of compartments and performance scores, as assessed by a supervising medical specialist. A Fisher's exact test was used to compare the proportions of collateral damage between groups. An independent-samples t-test was used to interpret total procedure times. The usability and technical factors involving HMD utilization were also assessed.Results:Combat medics in the HMD group released the anterior compartment (P <= .001) and deep posterior compartment (P = .008) significantly better. There was significantly more iatrogenic muscle (P <= .001) and venous damage (P <= .001) in the control group. The overall performance of combat medics in the HMD group was significantly better than that of the control group (P < .001). Combat medics in the control group were significantly faster (P = .012). The combat medics were very satisfied with the HMD. The HMD showed no major technical errors.Conclusions:This randomized controlled trial shows that a HMD providing telemedicine support leads to significantly better performance of a two-incision lower leg fasciotomy by a combat medic with less iatrogenic muscle and venous damage

    Telemedicine Improves Performance of a Two-Incision Lower Leg Fasciotomy by Combat Medics:A Randomized Controlled Trial

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    Introduction:The primary aim of this randomized controlled trial was to assess if a head-mounted display (HMD) providing telemedicine support improves performance of a two-incision lower leg fasciotomy by a NATO special operations combat medic (combat medic).Materials and Methods:Thirty-six combat medics were randomized into two groups: One group performed a two-incision lower leg fasciotomy with the assistance of an HMD, while the control group completed the procedure without guidance. A Mann-Whitney U test was used to determine the possible differences in release of compartments and performance scores, as assessed by a supervising medical specialist. A Fisher's exact test was used to compare the proportions of collateral damage between groups. An independent-samples t-test was used to interpret total procedure times. The usability and technical factors involving HMD utilization were also assessed.Results:Combat medics in the HMD group released the anterior compartment (P <= .001) and deep posterior compartment (P = .008) significantly better. There was significantly more iatrogenic muscle (P <= .001) and venous damage (P <= .001) in the control group. The overall performance of combat medics in the HMD group was significantly better than that of the control group (P < .001). Combat medics in the control group were significantly faster (P = .012). The combat medics were very satisfied with the HMD. The HMD showed no major technical errors.Conclusions:This randomized controlled trial shows that a HMD providing telemedicine support leads to significantly better performance of a two-incision lower leg fasciotomy by a combat medic with less iatrogenic muscle and venous damage

    Evaluation of MUSICA IASI tropospheric water vapour profiles using theoretical error assessments and comparisons to GRUAN Vaisala RS92 measurements

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    Volume mixing ratio water vapour profiles have been retrieved from IASI (Infrared Atmospheric Sounding Interferometer) spectra using the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) processor. The retrievals are done for IASI observations that coincide with Vaisala RS92 radiosonde measurements performed in the framework of the GCOS (Global Climate Observing System) Reference Upper-Air Network (GRUAN) in three different climate zones: the tropics (Manus Island, 2°S), mid-latitudes (Lindenberg, 52°N), and polar regions (Sodankylä, 67°N). The retrievals show good sensitivity with respect to the vertical H2O distribution between 1km above ground and the upper troposphere. Typical DOFS (degrees of freedom for signal) values are about 5.6 for the tropics, 5.1 for summertime mid-latitudes, 3.8 for wintertime mid-latitudes, and 4.4 for summertime polar regions. The errors of the MUSICA IASI water vapour profiles have been theoretically estimated considering the contribution of many different uncertainty sources. For all three climate regions, unrecognized cirrus clouds and uncertainties in atmospheric temperature have been identified as the most important error sources and they can reach about 25%. The MUSICA IASI water vapour profiles have been compared to 100 individual coincident GRUAN water vapour profiles. The systematic difference between the data is within 11% below 12km altitude; however, at higher altitudes the MUSICA IASI data show a dry bias with respect to the GRUAN data of up to 21%. The scatter is largest close to the surface (30%), but never exceeds 21% above 1km altitude. The comparison study documents that the MUSICA IASI retrieval processor provides H2O profiles that capture the large variations in H2O volume mixing ratio profiles well from 1km above ground up to altitudes close to the tropopause. Above 5km the observed scatter with respect to GRUAN data is in reasonable agreement with the combined MUSICA IASI and GRUAN random errors. The increased scatter at lower altitudes might be explained by surface emissivity uncertainties at the summertime continental sites of Lindenberg and Sodankylä, and the upper tropospheric dry bias might suggest deficits in correctly modelling the spectroscopic line shapes of water vapour

    The role of interdisciplinary collaboration for stated preference methods to value marine environmental goods and ecosystem services

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    With the increasing use of environmental valuation methods in coastal, marine and deep-sea settings, there is a growing need for the collaboration of natural scientists and environmental economists. Stated preference valuation methods in particular need to be based on sound natural science information and translate such information to be used in social surveys. This paper uses three applications to make explicit the flow of information between different disciplines in the preparation and implementation of stated preference studies. One approach for facilitating this flow is to increase knowledge and understanding of natural scientists on these methods. To address this, this paper highlights key opportunities and pitfalls and demonstrates those in the context of three case studies. It therefore provides guidance on stated preference valuation for natural scientists rather than for economists

    Structural dissection of a complex Bacteroides ovatus gene locus conferring xyloglucan metabolism in the human gut

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    The human gastrointestinal tract harbours myriad bacterial species, collectively termed the microbiota, that strongly influence human health. Symbiotic members of our microbiota play a pivotal role in the digestion of complex carbohydrates that are otherwise recalcitrant to assimilation. Indeed, the intrinsic human polysaccharide-degrading enzyme repertoire is limited to various starch-based substrates; more complex polysaccharides demand microbial degradation. Select Bacteroidetes are responsible for the degradation of the ubiquitous vegetable xyloglucans (XyGs), through the concerted action of cohorts of enzymes and glycan-binding proteins encoded by specific xyloglucan utilization loci (XyGULs). Extending recent (meta) genomic, transcriptomic and biochemical analyses, significant questions remain regarding the structural biology of the molecular machinery required for XyG saccharification. Here, we reveal the three-dimensional structures of an α-xylosidase, a β-glucosidase, and two α-L-arabinofuranosidases from the Bacteroides ovatus XyGUL. Aided by bespoke ligand synthesis, our analyses highlight key adaptations in these enzymes that confer individual specificity for xyloglucan side chains and dictate concerted, stepwise disassembly of xyloglucan oligosaccharides. In harness with our recent structural characterization of the vanguard endo-xyloglucanse and cell-surface glycan-binding proteins, the present analysis provides a near-complete structural view of xyloglucan recognition and catalysis by XyGUL proteins

    MUSICA MetOp/IASI {H2O;δD} pair retrieval simulations for validating tropospheric moisture pathways in atmospheric models

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    The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) has shown that the sensor IASI aboard the satellite MetOp can measure the free tropospheric {H2O,δD} pair distribution twice per day on a quasi-global scale. Such data are very promising for investigating tropospheric moisture pathways, however, the complex data characteristics compromise their usage in the context of model evaluation studies. Here we present a tool that allows for simulating MUSICA MetOp/IASI {H2O,δD} pair remote sensing data for a given model atmosphere, thereby creating model data that have the remote sensing data characteristics assimilated. This model data can then be compared to the MUSICA data. The retrieval simulation method is based on the physical principles of radiative transfer and we show that the uncertainty of the simulations is within the uncertainty of the MUSICA MetOp/IASI products, i.e. the retrieval simulations are reliable enough. We demonstrate the working principle of the simulator by applying it to ECHAM5-wiso model data. The few case studies clearly reveal the large potential of the MUSICA MetOp/IASI {H2O,δD} data pairs for evaluating modelled moisture pathways. The tool is made freely available in form of MATLAB and Python routines and can be easily connected to any atmospheric water vapour isotopologue model

    Combined Coronary CT-Angiography and TAVI-Planning: A Contrast-Neutral Routine Approach for Ruling-Out Significant Coronary Artery Disease

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    Background: Significant coronary artery disease (CAD) is a common finding in patients undergoing transcatheter aortic valve implantation (TAVI). Assessment of CAD prior to TAVI is recommended by current guidelines and is mainly performed via invasive coronary angiography (ICA). In this study we analyzed the ability of coronary CT-angiography (cCTA) to rule out significant CAD (stenosis ≥ 50%) during routine pre-TAVI evaluation in patients with high pre-test probability for CAD. Methods: In total, 460 consecutive patients undergoing pre-TAVI CT (mean age 79.6 ± 7.4 years) were included. All patients were examined with a retrospectively ECG-gated CT-scan of the heart, followed by a high-pitch-scan of the vascular access route utilizing a single intravenous bolus of 70 mL iodinated contrast medium. Images were evaluated for image quality, calcifications, and significant CAD; CT-examinations in which CAD could not be ruled out were defined as positive (CAD+). Routinely, patients received ICA (388/460; 84.3%; Group A), which was omitted if renal function was impaired and CAD was ruled out on cCTA (Group B). Following TAVI, clinical events were documented during the hospital stay. Results: cCTA was negative for CAD in 40.2% (188/460). Sensitivity, specificity, PPV, and NPV in Group A were 97.8%, 45.2%, 49.6%, and 97.4%, respectively. Median coronary artery calcium score (CAC) was higher in CAD+-patients but did not have predictive value for correct classification of patients with cCTA. There were no significant differences in clinical events between Group A and B. Conclusion: cCTA can be incorporated into pre-TAVI CT-evaluation with no need for additional contrast medium. cCTA may exclude significant CAD in a relatively high percentage of these high-risk patients. Thereby, cCTA may have the potential to reduce the need for ICA and total amount of contrast medium applied, possibly making pre-procedural evaluation for TAVI safer and faster
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