36 research outputs found

    Charged Current Neutrino Cross Section and Tau Energy Loss at Ultra-High Energies

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    We evaluate both the tau lepton energy loss produced by photonuclear interactions and the neutrino charged current cross section at ultra-high energies, relevant to neutrino bounds with Earth-skimming tau neutrinos, using different theoretical and phenomenological models for nucleon and nucleus structure functions. The theoretical uncertainty is estimated by taking different extrapolations of the structure function F2 to very low values of x, in the low and moderate Q2 range for the tau lepton interaction and at high Q2 for the neutrino-nucleus inelastic cross section. It is at these extremely low values of x where nuclear shadowing and parton saturation effects are unknown and could be stronger than usually considered. For tau and neutrino energies E=10^9 GeV we find uncertainties of a factor 4 for the tau energy loss and of a factor 2 for the charged current neutrino-nucleus cross section.Comment: 20 pages and 11 figure

    Propagation of three-dimensional bipolar ultrashort electromagnetic pulses in an inhomogeneous array of carbon nanotubes

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    We study the propagation of three-dimensional (3D) bipolar ultrashort electromagnetic pulses in an inhomogeneous array of semiconductor carbon nanotubes. The heterogeneity is represented by a planar region with an increased concentration of conduction electrons. The evolution of the electromagnetic field and electron concentration in the sample are governed by the Maxwell’s equations and continuity equation. In particular, nonuniformity of the electromagnetic field along the axis of the nanotubes is taken into account. We demonstrate that depending on values of the parameters of the electromagnetic pulse approaching the region with the higher electron concentration, the pulse is either reflected from the region or passes it. Specifically, our simulations demonstrate that after interacting with the higher-concentration area, the pulse can propagate steadily, without significant spreading. The possibility of such ultrashort electromagnetic pulses propagating in arrays of carbon nanotubes over distances significantly exceeding characteristic dimensions of the pulses makes it possible to consider them as 3D solitons

    Ultra-high energy cosmic ray investigations by means of EAS muon density measurements

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    A new approach to investigations of ultra-high energy cosmic rays based on the ground-level measurements of the spectra of local density of EAS muons at various zenith angles is considered. Basic features of the local muon density phenomenology are illustrated using a simple semi-analytical model. It is shown that muon density spectra are sensitive to the spectrum slope, primary composition, and to the features of hadronic interaction. New experimental data on muon bundles at zenith angles from 30 degrees to horizon obtained with the coordinate detector DECOR are compared with CORSIKA-based simulations. It is found that measurements of muon density spectra in inclined EAS give possibility to study characteristics of primary cosmic ray flux in a very wide energy range from 10^15 to 10^19 eV.Comment: 7 pages, 7 figures. Presented at CRIS-2006, Catania, Italy, May 29 - June 2, 2006. Accepted for publication in Nucl. Phys. B (Proc. Suppl.

    External nose reconstructions frontal flap and cartilage allograft: analysis of functional results

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    Reconstruction of EN with a frontal flap and a cartilaginous allograft made it possible to improve functional indicators in the studied patient population, the difference with preoperative estimates is statistically significant. The total share of excellent and satisfactory ratings after reconstruction ranged from 92.6% to 100%, depending on the parameter

    Measurements of integral muon intensity at large zenith angles

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    High-statistics data on near-horizontal muons collected with Russian-Italian coordinate detector DECOR are analyzed. Precise measurements of muon angular distributions in zenith angle interval from 60 to 90 degrees have been performed. In total, more than 20 million muons are selected. Dependences of the absolute integral muon intensity on zenith angle for several threshold energies ranging from 1.7 GeV to 7.2 GeV are derived. Results for this region of zenith angles and threshold energies have been obtained for the first time. The dependence of integral intensity on zenith angle and threshold energy is well fitted by a simple analytical formula.Comment: 4 pages, 4 figures, 1 tabl

    Clinical results of the complex prevention of the acute postoperative pancreatitis at the surgical gastroenterology

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    The article aims to study the results of the complex prevention of the acute postoperative pancreatitis in the surgical gastroenterology. Material and methods. 2968 patients with various disorders of the digestive system were operated. Empirical preventing of the acute postoperative pancreatitis was used in the control group. Complex prevention of the acute postoperative pancreatitis in the main group of patients included the use of Dalargin, intravenous infusion of Octreotide, duodenal trypsin enzyme inhibition; intraduodenal reversal of pancreatic secret; intraductal injection of Lidocaine and external transnasal drainage of the pancreatic and biliary ducts. Results. The frequency of acute postoperative pancreatitis was 12.2% in the main group. The frequency of acute postoperative pancreatitis was 36.9% in the control group. Increased frequency of a mild form of the acute postoperative pancreatitis observed in the main group compared with the control. At the same time reducing the frequency of the moderate severity and severity forms of the acute postoperative pancreatitis observed in the main group compared with the control. Reduction of the morbidity (13.6% vs. 25.1%), hospital mortality (1.6% vs. 3.5%), the duration of the postoperative hospital bed-day (12.1±0.4 vs. 16.7±0.6) were identified in the main group patients compared with the control group. Conclusion. The use of the given scheme for the complex prevention of the acute postoperative pancreatitis allowed significantly reduce the frequency and severity of illness, morbidity, reduce the duration of postoperative hospital bed-day and hospital mortality, as well as the frequency of both mild and severity, and fatal postoperative complications in all investigated groups of patients
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