1,045 research outputs found

    Fermion Virtual Effects in e+e−−>W+W−e^+ e^- -> W^+ W^- Cross Section

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    We analyse the contribution of new heavy virtual fermions to the e+e−→W+W−e^+e^- \rightarrow W^+W^- cross section. We find that there exists a relevant interplay between trilinear and bilinear oblique corrections. The result strongly depends on the chiral or vector--like nature of the new fermions. As for the chiral case we consider sequential fermions: one obtains substantial deviation from the Standard model prediction, making the effect possibly detectable at s=500\sqrt{s}=500 or 10001000 GeV linear colliders. As an example for the vector--like case we take a SUSY extension with heavy charginos and neutralinos: due to cancellation, the final effect turns out to be negligible.Comment: uuencoded, gz-compressed, tar-ed file. 8 pages, 4 EPS figures, uses EPSFIG.ST

    Testosterone insulin-like effects: an in vitro study on the short-term metabolic effects of testosterone in human skeletal muscle cells

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    Testosterone by promoting different metabolic pathways contributes to short-term homeostasis of skeletal muscle, the largest insulin-sensitive tissue and the primary site for insulin-stimulated glucose utilization. Despite evidences indicate a close relationship between testosterone and glucose metabolism, the molecular mechanisms responsible for a possible testosterone-mediated insulin-like effects on skeletal muscle are still unknown

    Noncommutative Electrodynamics

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    In this paper we define a causal Lorentz covariant noncommutative (NC) classical Electrodynamics. We obtain an explicit realization of the NC theory by solving perturbatively the Seiberg-Witten map. The action is polynomial in the field strenght FF, allowing to preserve both causality and Lorentz covariance. The general structure of the Lagrangian is studied, to all orders in the perturbative expansion in the NC parameter θ\theta. We show that monochromatic plane waves are solutions of the equations of motion to all orders. An iterative method has been developed to solve the equations of motion and has been applied to the study of the corrections to the superposition law and to the Coulomb law.Comment: 13 pages, 2 figures, one reference adde

    Many-core applications to online track reconstruction in HEP experiments

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    Interest in parallel architectures applied to real time selections is growing in High Energy Physics (HEP) experiments. In this paper we describe performance measurements of Graphic Processing Units (GPUs) and Intel Many Integrated Core architecture (MIC) when applied to a typical HEP online task: the selection of events based on the trajectories of charged particles. We use as benchmark a scaled-up version of the algorithm used at CDF experiment at Tevatron for online track reconstruction - the SVT algorithm - as a realistic test-case for low-latency trigger systems using new computing architectures for LHC experiment. We examine the complexity/performance trade-off in porting existing serial algorithms to many-core devices. Measurements of both data processing and data transfer latency are shown, considering different I/O strategies to/from the parallel devices.Comment: Proceedings for the 20th International Conference on Computing in High Energy and Nuclear Physics (CHEP); missing acks adde

    Efficacy of SSRIs on cognition of Alzheimer's disease patients treated with cholinesterase inhibitors.

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    Background: This study examines the joint effect on cognition of selective serotonin re-uptake inhibitors (SSRIs) and cholinesterase inhibitors (AChEIs) in depressed patients affected by Alzheimer’s disease (AD) living at home. Methods: The study was conducted in two different outpatient neurological clinics. 338 patients with probable ADwere treated with ChEis (donepezil, rivastigmine and galantamine) as per the clinician’s judgment and were observed for nine months. At study entry, participants underwent a multidimensional assessment evaluating cognitive, functional and psychobehavioral domains. All patients were evaluated at baseline, after one (T1), three (T2) and nine months (T3). Patients were grouped in three different categories (patients not depressed and not treated with SSRIs, patients depressed and treated with SSRIs, and patients depressed but not treated with SSRIs). Results: At baseline 182 were diagnosed as not depressed and not treated with SSRIs, 66 as depressed and treated with SSRIs, and 90 as depressed but not treated with SSRIs. The mean change in MMSE score from baseline to nine months showed that depressed patients not treated worsened in comparison with those not depressed and not treated with SSRIs (mean change −0.8±2.3 vs 0.04±2.9; p = 0.02) and patients depressed and treated with SSRI (mean change −0.8±2.3 vs 0.1±2.5; p = 0.03). Conclusions: In AD patients treated with AChEIs, SSRIs may exert some degree of protection against the negative effects of depression on cognition

    High-speed data transfer with FPGAs and QSFP+ modules

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    We present test results and characterization of a data transmission system based on a last generation FPGA and a commercial QSFP+ (Quad Small Form Pluggable +) module. QSFP+ standard defines a hot-pluggable transceiver available in copper or optical cable assemblies for an aggregated bandwidth of up to 40 Gbps. We implemented a complete testbench based on a commercial development card mounting an Altera Stratix IV FPGA with 24 serial transceivers at 8.5 Gbps, together with a custom mezzanine hosting three QSFP+ modules. We present test results and signal integrity measurements up to an aggregated bandwidth of 12 Gbps.Comment: 5 pages, 3 figures, Published on JINST Journal of Instrumentation proceedings of Topical Workshop on Electronics for Particle Physics 2010, 20-24 September 2010, Aachen, Germany(R Ammendola et al 2010 JINST 5 C12019

    GPU-based Real-time Triggering in the NA62 Experiment

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    Over the last few years the GPGPU (General-Purpose computing on Graphics Processing Units) paradigm represented a remarkable development in the world of computing. Computing for High-Energy Physics is no exception: several works have demonstrated the effectiveness of the integration of GPU-based systems in high level trigger of different experiments. On the other hand the use of GPUs in the low level trigger systems, characterized by stringent real-time constraints, such as tight time budget and high throughput, poses several challenges. In this paper we focus on the low level trigger in the CERN NA62 experiment, investigating the use of real-time computing on GPUs in this synchronous system. Our approach aimed at harvesting the GPU computing power to build in real-time refined physics-related trigger primitives for the RICH detector, as the the knowledge of Cerenkov rings parameters allows to build stringent conditions for data selection at trigger level. Latencies of all components of the trigger chain have been analyzed, pointing out that networking is the most critical one. To keep the latency of data transfer task under control, we devised NaNet, an FPGA-based PCIe Network Interface Card (NIC) with GPUDirect capabilities. For the processing task, we developed specific multiple ring trigger algorithms to leverage the parallel architecture of GPUs and increase the processing throughput to keep up with the high event rate. Results obtained during the first months of 2016 NA62 run are presented and discussed

    Optimization of quasi-hemispherical CdZnTe detectors by means of first principles simulation

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    In this paper we present the development of quasi-hemispherical gamma-ray detectors based on CdZnTe. Among the possible single-polarity electrode configurations, such as coplanar, pixelated, or virtual Frisch-grid geometries, quasi-hemispherical detectors are the most cost-effective alternative with comparable raw energy resolution in the high and low energy range. The optimal configuration of the sensor in terms of dimension of the crystals and electrode specifications has been first determined by simulations, and successively validated with experimental measures. Spectra from different sources have been acquired to evaluate the detectors performances. Three types of detectors with different CZT volumes have been fabricated, namely 10 × 10 × 5 mm3, 15 × 15 × 10 mm3 and 20 × 20 × 10 mm3. In the case of 10 × 10 × 5 mm3 crystals, the optimum pixel size determined by our simulation tool was confirmed by experiments: the best spectroscopic resolution of 1.3% at 662 keV has been found for a 750 Î¼m diameter pixel detector. The best energy resolution values obtained for the 15 × 15 × 10 mm3 and 20 × 20 × 10 mm3 detectors were respectively 1.7% and 2.7% at 662 keV
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