2,431 research outputs found

    Prototyping of petalets for the Phase-II Upgrade of the silicon strip tracking detector of the ATLAS Experiment

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    In the high luminosity era of the Large Hadron Collider, the HL-LHC, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The ITk consists of a silicon pixel and a strip detector and exploits the concept of modularity. Prototyping and testing of various strip detector components has been carried out. This paper presents the developments and results obtained with reduced-size structures equivalent to those foreseen to be used in the forward region of the silicon strip detector. Referred to as petalets, these structures are built around a composite sandwich with embedded cooling pipes and electrical tapes for routing the signals and power. Detector modules built using electronic flex boards and silicon strip sensors are glued on both the front and back side surfaces of the carbon structure. Details are given on the assembly, testing and evaluation of several petalets. Measurement results of both mechanical and electrical quantities are shown. Moreover, an outlook is given for improved prototyping plans for large structures.Comment: 22 pages for submission for Journal of Instrumentatio

    Implementation of a children's hospital-wide central venous catheter insertion and maintenance bundle

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    Background: Central venous catheter-associated bloodstream infections in children are an increasingly recognized serious safety problem worldwide, but are often preventable. Central venous catheter bundles have proved effective to prevent such infections. Successful implementation requires changes in the hospital system as well as in healthc

    Congenital anomalies in low- and middle-income countries: the unborn child of global surgery.

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    Surgically correctable congenital anomalies cause a substantial burden of global morbidity and mortality. These anomalies disproportionately affect children in low- and middle-income countries (LMICs) due to sociocultural, economic, and structural factors that limit the accessibility and quality of pediatric surgery. While data from LMICs are sparse, available evidence suggests that the true human and financial cost of congenital anomalies is grossly underestimated and that pediatric surgery is a cost-effective intervention with the potential to avert significant premature mortality and lifelong disability

    Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC

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    While the tracking detectors of the ATLAS and CMS experiments have shown excellent performance in Run 1 of LHC data taking, and are expected to continue to do so during LHC operation at design luminosity, both experiments will have to exchange their tracking systems when the LHC is upgraded to the high-luminosity LHC (HL-LHC) around the year 2024. The new tracking systems need to operate in an environment in which both the hit densities and the radiation damage will be about an order of magnitude higher than today. In addition, the new trackers need to contribute to the first level trigger in order to maintain a high data-taking efficiency for the interesting processes. Novel detector technologies have to be developed to meet these very challenging goals. The German groups active in the upgrades of the ATLAS and CMS tracking systems have formed a collaborative "Project on Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC" (PETTL), which was supported by the Helmholtz Alliance "Physics at the Terascale" during the years 2013 and 2014. The aim of the project was to share experience and to work together on key areas of mutual interest during the R&D phase of these upgrades. The project concentrated on five areas, namely exchange of experience, radiation hardness of silicon sensors, low mass system design, automated precision assembly procedures, and irradiations. This report summarizes the main achievements

    Influence of a novel classification of the papilla of Vater on the outcome of needle-knife fistulotomy for biliary cannulation

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    BACKGROUND: Existing proposed classification systems for the Papilla of Vater (PV) suboptimally account for all relevant, encountered PV appearances, are too complex or have not been assessed for intra- or interobserver variability. We proposed a novel endoscopic classification system for PV, determined its inter- and intraobserver rates and used the classification system to assess whether the success and complications of needle-knife fistulotomy (NKF) are influenced by the morphology of the PV. METHODS: The classification system was developed by expert endoscopists. To evaluate the inter- and intraobserver agreement, an online questionnaire was sent to 20 endoscopists from several countries (10 experts and 10 nonexperts) that included 50 images of papillae of Vater divided among various categories. Four weeks later, a second survey, with the images from the first questionnaire randomly reordered, was sent to the same endoscopists. The inter- and intraobserver agreements among the experts and nonexperts was calculated. Using the proposed classification system, all 361 consecutive patients who underwent NKF for biliary access to a naïve papilla were prospectively enrolled in the study. RESULTS: The novel classification system comprises 7 categories: type I, flat type, lacking an oral protrusion; type IIA, prominent tubular nonpleated type, with an oral protrusion and  2 transverse folds over the oral protrusion; type IIC: prominent bulging type, with an enlarged and bulging oral protrusion; type IIIA, diverticular-intradiverticular type, with a papillary orifice inside the diverticulum; type IIIB: diverticular-diverticular border type, with a papillary orifice less than 2 cm from the diverticular border; type IV: unclassified papilla, with no morphology classified in the other categories. The interobserver agreement between experts was substantial (K = 0.611, 95% CI 0.498-0.709) and was higher than that between nonexperts (K = 0.516; 95% CI 0.410-0.636). The intraobserver agreement was substantial among both experts (K = 0,651; 95% CI 0.586-0.715) and nonexperts (K = 0.646, 95% CI 0.615-0.677). In a multivariate model, type IIIA and IIIB were the only independent risk factors for difficult rescue NKF biliary cannulation (P = 0.003 and P = 0.019, respectively), and type I and type IIB were the only independent risk factors for a prolonged cannulation time using NKF (P < 0.001 and P = 0.005, respectively). CONCLUSIONS: The novel endoscopic classification system for PV is highly reproducible among experienced ERCPists according to the substantial level of agreement between experts. However, nonexperts require further training in its use. Using the novel classification system, we identified different types of papillae significantly associated with a lower efficacy of NKF and a prolonged time to obtain successful biliary cannulation using NKF.publishersversionpublishe

    Investigations into the impact of locally modified sensor architectures on the detection efficiency of silicon micro-strip sensors

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    The High Luminosity Upgrade of the LHC will require the replacement of the Inner Detector of ATLAS with the Inner Tracker (ITk) in order to cope with higher radiation levels and higher track densities. Prototype silicon strip detector modules are currently developed and their performance is studied in both particle test beams and X-ray beams. In previous test beam measurements of prototype modules, the response of silicon sensors has been studied in detailed scans across individual sensor strips. These scans found instances of sensor strips collecting charge across areas on the sensor deviating from the geometrical width of a sensor strip. The variations have been linked to local features of the sensor architecture. This paper presents results of detailed sensor measurements in both X-ray and particle beams investigating the impact of sensor features (metal pads and p-stops) on the sensor strip response

    Mapping The In-Plane Electric Field Inside Irradiated Diodes

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    A significant aspect of the Phase-II Upgrade of the ATLAS detector is the replacement of the current Inner Detector with the ATLAS Inner Tracker (ITk). The ATLAS ITk is an all-silicon detector consisting of a pixel tracker and a strip tracker. Sensors for the ITk strip tracker have been developed to withstand the high radiation environment in the ATLAS detector after the High Luminosity Upgrade of the Large Hadron Collider at CERN, which will significantly increase the rate of particle collisions and resulting particle tracks. During their operation in the ATLAS detector, sensors for the ITk strip tracker are expected to accumulate fluences up to 1.61015neq/cm2 (including a safety factor of 1.5), which will significantly affect their performance. One characteristic of interest for highly irradiated sensors is the shape and homogeneity of the electric field inside its active area. For the results presented here, diodes with edge structures similar to full size ATLAS sensors were irradiated up to fluences comparable to those in the ATLAS ITk strip tracker and their electric fields mapped using a micro-focused X-ray beam (beam diameter 23m2). This study shows the extension and shape of the electric field inside highly irradiated diodes over a range of applied bias voltages. Additionally, measurements of the outline of the depleted sensor areas allow a comparison of the measured leakage current for different fluences with expectations for the corresponding active areas

    Workshop Report: Concepts and methods in the economics of nutrition - Gateways to better economic evaluation of nutrition interventions

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    Improving health through better nutrition of the population may contribute to enhanced efficiency and sustainability of healthcare systems. A recent expert meeting investigated in detail a number of methodological aspects related to the discipline of nutrition economics. The role of nutrition in health maintenance and in the prevention of non-communicable diseases is now generally recognised. However, the main scope of those seeking to contain healthcare expenditures tends to focus on the management of existing chronic diseases. Identifying additional relevant dimensions to measure and the context of use will become increasingly important in selecting and developing outcome measurements for nutrition interventions. The translation of nutrition-related research data into public health guidance raises the challenging issue of carrying out more pragmatic trials in many areas where these would generate the most useful evidence for health policy decision-making. Nutrition exemplifies all the types of interventions and policy which need evaluating across the health field. There is a need to start actively engaging key stakeholders in order to collect data and to widen health technology assessment approaches for achieving a policy shift from evidence-based medicine to evidence-based decision-making in the field of nutrition
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