1,438 research outputs found

    A new anti-neutrino detection technique based on positronium tagging with plastic scintillators

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    The main signature for anti-neutrino detection in reactor and geo-neutrino experiments based on scintillators is provided by the space-time coincidence of positron and neutron produced in the Inverse Beta Decay reaction. Such a signature strongly suppresses backgrounds and allows for measurements performed underground with a relatively high signal-to-background ratio. In an aboveground environment, however, the twofold coincidence technique is not sufficient to efficiently reject the high background rate induced by cosmogenic events. Enhancing the positron-neutron twofold coincidence efficiency has the potential to pave the way future aboveground detectors for reactor monitoring. We propose a new detection scheme based on a threefold coincidence, between the positron ionization, the ortho-positronium (o-Ps) decay, and the neutron capture, in a sandwich detector with alternated layers of plastic scintillator and aerogel powder. We present the results of a set of dedicated measurements on the achievable light yield and on the o-Ps formation and lifetime. The efficiencies for signal detection and background rejection of a preliminary detector design are also discussed.Comment: 18 pages, 10 figure

    Optical properties of highly n-doped germanium obtained by in situ doping and laser annealing

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    High n-type doping in germanium is essential for many electronic and optoelectronic applications especially for high performance Ohmic contacts, lasing and mid-infrared plasmonics. We report on the combination of in situ doping and excimer laser annealing to improve the activation of phosphorous in germanium. An activated n-doping concentration of 8.8  ×  1019 cm−3 has been achieved starting from an incorporated phosphorous concentration of 1.1  ×  1020 cm−3. Infrared reflectivity data fitted with a multi-layer Drude model indicate good uniformity over a 350 nm thick layer. Photoluminescence demonstrates clear bandgap narrowing and an increased ratio of direct to indirect bandgap emission confirming the high doping densities achieved

    THREE-DIMENSIONAL SPORT MOVEMENT ANALYSIS BY MEANS OF FREE FLOATING TV CAMERAS WITH VARIABLE OPTICS

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    INTRODUCTION: Video analysis and off-line manual digitalization is usually used for 2-D and 3-D studies of human movement in sport science. The main advantage of this approach, with respect to the recourse to opto-electronic automatic motion analyzers, is the high flexibility in system set-up, the avoidance of marking procedures and the possibility of successful operation in a wide range of environmental situations. Such features turn out to be particularly important for recordings to be performed in the frame of high-level competition, when the experimental set-up must be adapted to a pre-defined competitive environment, without interfering with the performances of the athletes. However, when methods proper to conventional close-range photogrammetry are used, most of the advantages offered by the flexibility of video analysis are not obtained. Particularly critical is the restriction of the useful calibrated volume to the field of view made possible by fixed pairs of TV cameras. In this case the useful sequence of images (where the dimension of the acquired subject allows one to limit macroscopic digitalization errors) is often insufficient for the analysis of a complete movement cycle. This limitation hinders a fruitful application of video analysis in the frame of sport activities (alpine and Nordic skiing, swimming, track and field) in which the execution of the particular technical movement is performed within a large physical space. A solution to the problem is proposed based on the use of free moving and zooming cameras. The corresponding dedicated software for repeated calibration based on Direct Linear Transformation (DLT)(Abdel Aziz and Karara, 1971) is described. Results of recording performed in the laboratory are discussed aiming at the validation of the implemented method. The description of the methodology for the recording of sport activities and the presentation of the related results confirm the operational feasibility of the proposed method and the reliability of the resulting quantitative kinematics analysis

    Análisis de imágenes satelitales con R: patrones espaciales de la correlación cruzada de series temporales de imágenes Modis de temperatura y productividad vegetal

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    R se perfila como uno de los entornos más completos para realizar análisis de datos espacio-temporales de grandes bases de datos abiertos satelitales. Presentamos un ejemplo de análisis de series temporales de productos MODIS para identificar áreas con distinto patrón de funcionamiento ecológico, usando medidas de correlación cruzada de series de tiempo y agrupamiento con redes neuronales autoorganizadas.Sociedad Argentina de Informática e Investigación Operativ

    A five-year survey for plastic surgery malpractice claims in Rome, Italy

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    (1) Introduction: Medical malpractice claims against both health institutions and physicians are a crucial topic in Italy, as well as in other countries, particularly regarding civil proceedings. Our study reports an analysis of all of the malpractice judgments concerning plastic surgery decided in the Civil Court of Rome between 2012 and 2016. (2) Methods: the database of the Observatory Project on Medical Responsibility (ORMe) was analyzed, which collects all of the judgments of the Civil Court of Rome, that is, the first instance district court. Therefore, neither the jurisprudence of the second level court nor that of the Supreme Court was taken into account. (3) Results: 144 judgments concerning plastic surgery were delivered in the five-year period of 2012–2016 (corresponding to 10.6% of total professional liability verdicts of the Civil Court of Rome in the same period). In 101/144 cases (70.14%), the claim was accepted. A total of €4,727,579.00 was paid in compensation for plastic surgery malpractice claims, with a range from a minimum amount of €1555.96 to a maximum amount of €1,425,155.00 and an average compensation of €46,807.71 per claim that was significantly lower compared to other surgical disciplines. (4) Conclusions: Our data confirm that the analyzed branch has a high litigation rate, with a prevalence of convictions for cosmetic procedures over reconstructive ones, both for malpractice and for violation of the informed consent. Plastic surgery is also confirmed among those branches in which the professionals are more frequently sued compared to health institutions

    Análisis de imágenes satelitales con R: patrones espaciales de la correlación cruzada de series temporales de imágenes Modis de temperatura y productividad vegetal

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    R se perfila como uno de los entornos más completos para realizar análisis de datos espacio-temporales de grandes bases de datos abiertos satelitales. Presentamos un ejemplo de análisis de series temporales de productos MODIS para identificar áreas con distinto patrón de funcionamiento ecológico, usando medidas de correlación cruzada de series de tiempo y agrupamiento con redes neuronales autoorganizadas.Sociedad Argentina de Informática e Investigación Operativ

    Análisis de imágenes satelitales con R: patrones espaciales de la correlación cruzada de series temporales de imágenes Modis de temperatura y productividad vegetal

    Get PDF
    R se perfila como uno de los entornos más completos para realizar análisis de datos espacio-temporales de grandes bases de datos abiertos satelitales. Presentamos un ejemplo de análisis de series temporales de productos MODIS para identificar áreas con distinto patrón de funcionamiento ecológico, usando medidas de correlación cruzada de series de tiempo y agrupamiento con redes neuronales autoorganizadas.Sociedad Argentina de Informática e Investigación Operativ

    COVID-19 and MIS-C treatment in children—results from an international survey

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    Children have been mostly excluded from COVID-19 clinical trials, and, as a result, most medicines approved for COVID-19 have no pediatric indication. In addition, access to COVID-19 therapeutics remains limited. Collecting physicians’ experiences with off-label use of therapeutics is important to inform global prioritization processes and better target pediatric research and development. A standardized questionnaire was designed to explore the use of therapeutics used to treat COVID-19 and multisystem inflammatory syndrome in children (MIS-C) in pediatric patients globally. Seventy-three physicians from 29 countries participated. For COVID-19, steroids were used by 75.6% of respondents; remdesivir and monoclonal antibodies were prescribed by 48.6% and 27.1% of respondents, respectively. For MIS-C, steroids were prescribed by 79.1% of respondents and intravenous immunoglobulins by 69.6%. The use of these products depended on their pediatric approval and the limited availability of antivirals and most monoclonal antibodies in Africa, South America, Southeast Asia, and Eastern Europe. Off-label prescription resulted widespread due to the paucity of clinical trials in young children at the time of the survey; though, based on our survey results, it was generally safe and led to clinical benefits. Conclusion: This survey provides a snapshot of current practice for treating pediatric COVID-19 worldwide, informing global prioritization efforts to better target pediatric research and development for COVID-19 therapeutics. Off-label use of such medicines is widespread for the paucity of clinical trials under 12 years and 40 kg, though appears to be safe and generally results in clinical benefits, even in young children. However, access to care, including medicine availability, differs widely globally. Clinical development of COVID-19 antivirals and monoclonal antibodies requires acceleration to ensure pediatric indication and allow worldwide availability of therapeutics that will enable more equitable access to COVID-19 treatment. What is Known: • Children have been mostly excluded from COVID-19 clinical trials, and, as a result, most medicines approved for COVID-19 have no pediatric indication. • Access to care differs widely globally, so because of the diversity of national healthcare systems; the unequal availability of medicines for COVID-19 treatment represents an obstacle to the pediatric population's universal right to health care. What is New: • Off-label COVID-19 drug prescription is widespread due to the lack of clinical trials in children younger than 12 years and weighing less than 40 kg, but relatively safe and generally leading to clinical benefit. • The application of the GAP-f framework to COVID-19 medicines is crucial, ensuring widespread access to all safe and effective drugs, enabling the rapid development of age-appropriate formulations, and developing specific access plans (including stability, storage, packaging, and labeling) for distribution in low- and middle-income countries (LMICs). Antivirals and monoclonal antibodies may benefit from the acceleration to reach widespread and equal diffusion

    Defective One- or Two-electron Reduction of the Anticancer Anthracycline Epirubicin in Human Heart RELATIVE IMPORTANCE OF VESICULAR SEQUESTRATION AND IMPAIRED EFFICIENCY OF ELECTRON ADDITION

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    One-electron quinone reduction and two-electron carbonyl reduction convert the anticancer anthracycline doxorubicin to reactive oxygen species (ROS) or a secondary alcohol metabolite that contributes to inducing a severe form of cardiotoxicity. The closely related analogue epirubicin induces less cardiotoxicity, but the determinants of its different behavior have not been elucidated. We developed a translational model of the human heart and characterized whether epirubicin exhibited a defective conversion to ROS and secondary alcohol metabolites. Small myocardial samples from cardiac surgery patients were reconstituted in plasma that contained clinically relevant concentrations of doxorubicin or epirubicin. In this model only doxorubicin formed ROS, as detected by fluorescent probes or aconitase inactivation. Experiments with cell-free systems and confocal laser scanning microscopy studies of H9c2 cardiomyocytes suggested that epirubicin could not form ROS because of its protonation-dependent sequestration in cytoplasmic acidic organelles and the consequent limited localization to mitochondrial one-electron quinone reductases. Accordingly, blocking the protonation-sequestration mechanism with the vacuolar H+-ATPase inhibitor bafilomycin A1 relocalized epirubicin to mitochondria and increased its conversion to ROS in human myocardial samples. Epirubicin also formed ∼60% less alcohol metabolites than doxorubicin, but this was caused primarily by its higher Km and lower Vmax values for two-electron carbonyl reduction by aldo/keto-reductases of human cardiac cytosol. Thus, vesicular sequestration and impaired efficiency of electron addition have separate roles in determining a defective bioactivation of epirubicin to ROS or secondary alcohol metabolites in the human heart. These results uncover the molecular determinants of the reduced cardiotoxicity of epirubicin and serve mechanism-based guidelines to improving antitumor therapies
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