1,376 research outputs found

    Remote event analyses of LOPES-10

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    Sensitivity Analysis and Cross Sections Data Adjustment for Multigroup Transport and Diffusion

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    Uncertainties in basic nuclear data and other quantities involved in the characterization of an experiment affect the accuracy of the results when the respective experiment is modelled. The impact of these uncertainties on computed responses can be assessed by combining the sensitivities of these responses to the input parameters with data uncertainties and covariances. Furthermore, best estimates of both the input parameters and recomputed responses, with reduced uncertainties, can be obtained by using data assimilation and adjustment procedures. This paper reports the results of using the data adjustment methodology in conjunction with the well-known Godiva experiment and a partial set of uncertainties from the ZZ-COV-15 library for U-235 and U-238, together with sensitivities computed with APOLLO transport code by the Adjoint Sensitivity Analysis Procedure, to obtain best-estimate values for the k eigenvalue of the system, with reduced uncertainties. In parallel, sensitivities were also computed using COBAYA diffusion code, compared with those produced by APOLLO, and then employed in the adjustment formalism to obtain the adjusted k eigenvalue and its corresponding reduced uncertainty

    Absolute calibration of the LOPES antenna system

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    Radio emission in extensive air showers arises from an interaction with the geomagnetic field and is subject of theoretical studies. This radio emission has advantages for the detection of high energy cosmic rays compared to secondary particle or fluorescence measurement methods. Radio antennas like the LOPES30 antenna system are suited to investigate this emission process by detecting the radio pulses. The characteristic observable parameters like electric field strength and pulse length require a calibration which was done with a reference radio source resulting in an amplification factor representing the system behavior in the environment of the KASCADE-Grande experiment. Knowing the amplification factor and the gain of the LOPES antennas LOPES30 is calibrated absolutely for systematic analyses of the radio emission.Comment: 5 pages, Proceedings of International Workshop on Acoustic and Radio EeV Neutrino detection Activities: ARENA, May 17-19, 2005, DESY Zeuthe

    Mining the ESO WFI and INT WFC archives for known Near Earth Asteroids. Mega-Precovery software

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    The ESO/MPG WFI and the INT WFC wide field archives comprising 330,000 images were mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 asteroids (44 PHAs and 108 other NEAs) were identified using the PRECOVERY software, their astrometry being measured on 761 images and sent to the Minor Planet Centre. Both recoveries and precoveries were reported, including prolonged orbital arcs for 18 precovered objects and 10 recoveries. We analyze all new opposition data by comparing the orbits fitted before and after including our contributions. We conclude the paper presenting Mega-Precovery, a new online service focused on data mining of many instrument archives simultaneously for one or a few given asteroids. A total of 28 instrument archives have been made available for mining using this tool, adding together about 2.5 million images forming the Mega-Archive.Comment: Accepted for publication in Astronomische Nachrichten (Sep 2012

    Radioelectric Field Features of Extensive Air Showers Observed with CODALEMA

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    Based on a new approach to the detection of radio transients associated with extensive air showers induced by ultra high energy cosmic rays, the experimental apparatus CODALEMA is in operation, measuring about 1 event per day corresponding to an energy threshold ~ 5. 10^16 eV. Its performance makes possible for the first time the study of radio-signal features on an event-by-event basis. The sampling of the magnitude of the electric field along a 600 meters axis is analyzed. It shows that the electric field lateral spread is around 250 m (FWHM). The possibility to determine with radio both arrival directions and shower core positions is discussed.Comment: Accepted for publication in Astroparticle Physic

    Primary and secondary prevention to effectively reduce the risk of bisphosphonate-related osteonecrosis of the jaw in patients with bone metastases .

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    Background Bone is one of the most frequent sites of metastasis in patients with advanced cancer. Nearly all patients with myeloma, 65–75% of patients with prostate or breast cancer, and 30–40% of patients with lung cancer or other solid tumors, eventually develop bone metastases. Bisphosphonates (BP), particularly zoledronic acid and denosumab, were demonstrated to effectively reduce skeletal complications in patients with bone metastases. However, bisphosphonate-related osteonecrosis of the jaw (BRONJ) can occur spontaneously, favored by dental extraction, dental implant surgery, or denture wearing. The purpose of this study was to underline the role of dental prevention as an effective tool to reduce the risk of BRONJ. Material and methods BRONJ was identified with the standardized query “osteonecrosis” among all data from patients treated at Modena Cancer Center from 2005 to 2016. For each case, demographic and medical information were analyzed, as well as data about notification (year of occurrence, outcome), type and duration of BP exposure, and associated risk factors (dento-alveolar surgery, chemotherapy, antiangiogenics). Data were differently analyzed taking into account the implementation of a Dental Prevention Service in patients who are candidates for BP therapy.Results Among 1663 patients treated with BP, 63 cases of BRONJ were identified (3.8%). 44 female and 19 men with a median age of 69 years (range 47-90 years), have been treated with BP for bone metastases from breast cancer (54%), hematologic malignancy (21%), prostate cancer (13%), renal cancer (5%), lung cancer (2%) and other tumors (5%). 15 maxillae and 48 mandibles were involved. The trigger event was a dental extraction in 29% of the cases, being spontaneously the other 71%. The median time to BRONJ was 28 months (range 1-89.1 months) from the first dose of BP, and 25 was the mean number of BP doses administered before BRONJ. Overall, a preliminary odontoiatric evaluation was performed in only 14 cases (22%). All but one of these dentistry opinions were obtained after 2010 when the Dental Prevention Service was created, which is a drop out of the risk of BRONJ from 4.1 to 1.9%. Conclusions. Prevention of the BRONJ is critical in in bone metastatic patients. The incidence of BRONJ over time can drop to 1.9% when primary and secondary prevention measures are implemented in routine clinical practice

    Fast and reliable pricing of American options with local volatility

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    We present globally convergent multigrid methods for the nonsymmetric obstacle problems as arising from the discretization of Black—Scholes models of American options with local volatilities and discrete data. No tuning or regularization parameters occur. Our approach relies on symmetrization by transformation and data recovery by superconvergence

    Features of Muon Arrival Time Distributions of High Energy EAS at Large Distances From the Shower Axis

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    In view of the current efforts to extend the KASCADE experiment (KASCADE-Grande) for observations of Extensive Air Showers (EAS) of primary energies up to 1 EeV, the features of muon arrival time distributions and their correlations with other observable EAS quantities have been scrutinised on basis of high-energy EAS, simulated with the Monte Carlo code CORSIKA and using in general the QGSJET model as generator. Methodically various correlations of adequately defined arrival time parameters with other EAS parameters have been investigated by invoking non-parametric methods for the analysis of multivariate distributions, studying the classification and misclassification probabilities of various observable sets. It turns out that adding the arrival time information and the multiplicity of muons spanning the observed time distributions has distinct effects improving the mass discrimination. A further outcome of the studies is the feature that for the considered ranges of primary energies and of distances from the shower axis the discrimination power of global arrival time distributions referring to the arrival time of the shower core is only marginally enhanced as compared to local distributions referring to the arrival of the locally first muon.Comment: 24 pages, Journal Physics G accepte
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