4,457 research outputs found

    The First Year IceCube-DeepCore Results

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    The IceCube Neutrino Observatory includes a tightly spaced inner array in the deepest ice, called DeepCore, which gives access to low-energy neutrinos with a sizable surrounding cosmic ray muon veto. Designed to be sensitive to neutrinos at energies as low as 10 GeV, DeepCore will be used to study diverse physics topics with neutrino signatures, such as dark matter annihilations and atmospheric neutrino oscillations. The first year of DeepCore physics data-taking has been completed, and the first observation of atmospheric neutrino-induced cascades with IceCube and DeepCore are presented.Comment: 4 pages, 3 figures, TAUP 2011 (Journal of Physics: Conference Series (JCPS)

    Hematologic, hepatic, and renal function changes in hospitalized patients with Middle East respiratory syndrome coronavirus

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    Background There are no longitudinal data on the changes in hematologic, hepatic, and renal function findings in patients with Middle East respiratory syndrome coronavirus (MERS‐CoV) infection. Methods This is a retrospective cohort study of 16 MERS‐CoV patients, to describe the hematological, hepatic, and renal findings of patients with MERS‐CoV. Results During the 21 days of observation, there was no significant change in the hepatic panel or creatinine tests. There was a significant increase in the mean ± SD of the white blood cell count from 8.3 ± 4.6 to 14.53 ± 7 (P value = 0.001) and an increase in mean ± SD of the absolute neutrophil count from 6.33 ± 4.2 to 12 ± 5.5 (P value = 0.015). Leukocytosis was observed in 31% (5/16) of the patients on day 1 and in 80% (4/5) on day 21. Transient leukopenia developed in 6% (1/16) of the patients on day 1 and in 13% (1/8) on day 8. None of the patients had neutropenia. Lymphopenia was a prominent feature with a rate of 44% (7/16) of the patients on day 1 and 60% (3/5) on day 21. Lymphocytosis was not a feature of MERS‐CoV infection. Thrombocytopenia developed in 31% (5/16) of the patients on day 1 and 40% (2/5) on day 21. Thrombocytosis was not a prominent feature and was observed in 6% (1/16) of the patients on day 1 and 17% (1/6) on day 9. Conclusions Patients with MERS‐CoV infection showed variable hematologic parameters over time. Lymphocytosis and neutropenia were not features of MERS‐CoV infection

    Comparison anti-giardia activity of Satureja hortensis alcoholic extract and metronidazole in vitro

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    Background and aims: Giardiasis is known as intestinal infection and created by the flagellate protozoan Giardia lamblia. Some studies showed that phenolic components, present in plant extracts and essential oils, have anti-Giardia activity. The current study was performed to compare anti-Giardia activity of Satureja hortensis (SH) alcoholic extract and metronidazole in vitro. Methods: In this Laboratory-experimental study, it was separated cysts from the feces by Bingham procedure with minor modification. The numbers of cysts were calculated with Hemusytumetr and the purified cysts of Giardia lamblia (500 µl) were exposed with 500 µl of extract at concentrations of 10, 100 and 200 mg/ml and 125 mg/kg of metronidazole for 30, 60 and 120 min. The numbers of dead and live cysts was enumerated with a microscope. Results: Findings in the currnt studyshowed an increase in anti-Giardia activity of extract at high concentrations with increasing time. SH, at 100 mg/ml killed 53 in 30 min, 68 in 60 min and 78 in 120 min. Also, the extract killed by 62 in 30 min, about 88 in 60 minutes and 92 in 120 minutes. The drug had similar effects in 60 and 120 minutes, but it killed 83 in 30 minutes. Conclusion: SH alcoholic extract showed anti-Giardia activity at high rates and more time. Thus, SH extract at 200 mg may be suitable alternative for Metronidazole, without side effects. However, anti-Giardia activity of SH needs to more attentions, especially clinical investigations

    Techniques for measuring atmospheric aerosols at the High Resolution Fly's Eye experiment

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    We describe several techniques developed by the High Resolution Fly's Eye experiment for measuring aerosol vertical optical depth, aerosol horizontal attenuation length, and aerosol phase function. The techniques are based on measurements of side-scattered light generated by a steerable ultraviolet laser and collected by an optical detector designed to measure fluorescence light from cosmic-ray air showers. We also present a technique to cross-check the aerosol optical depth measurement using air showers observed in stereo. These methods can be used by future air fluorescence experiments.Comment: Accepted for publication in Astroparticle Physics Journal 16 pages, 9 figure

    Size Control in the Nanoprecipitation Process of Stable Iodine (127I) Using Microchannel Reactor—Optimization by Artificial Neural Networks

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    In this study, nanosuspension of stable iodine (127I) was prepared by nanoprecipitation process in microfluidic devices. Then, size of particles was optimized using artificial neural networks (ANNs) modeling. The size of prepared particles was evaluated by dynamic light scattering. The response surfaces obtained from ANNs model illustrated the determining effect of input variables (solvent and antisolvent flow rate, surfactant concentration, and solvent temperature) on the output variable (nanoparticle size). Comparing the 3D graphs revealed that solvent and antisolvent flow rate had reverse relation with size of nanoparticles. Also, those graphs indicated that the solvent temperature at low values had an indirect relation with size of stable iodine (127I) nanoparticles, while at the high values, a direct relation was observed. In addition, it was found that the effect of surfactant concentration on particle size in the nanosuspension of stable iodine (127I) was depended on the solvent temperature. © 2015, American Association of Pharmaceutical Scientists

    Stakeholder theory and management: Understanding longitudinal collaboration networks

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    This paper explores the evolution of research collaboration networks in the 'stakeholder theory and management' (STM) discipline and identifies the longitudinal effect of co-authorship networks on research performance, i.e., research productivity and citation counts. Research articles totaling 6,127 records from 1989 to 2020 were harvested from the Web of Science Database and transformed into bibliometric data using Bibexcel, followed by applying social network analysis to compare and analyze scientific collaboration networks at the author, institution and country levels. This work maps the structure of these networks across three consecutive sub-periods (t1: 1989-1999; t2: 2000-2010; t3: 2011-2020) and explores the association between authors' social network properties and their research performance. The results show that authors collaboration network was fragmented all through the periods, however, with an increase in the number and size of cliques. Similar results were observed in the institutional collaboration network but with less fragmentation between institutions reflected by the increase in network density as time passed. The international collaboration had evolved from an uncondensed, fragmented and highly centralized network, to a highly dense and less fragmented network in t3. Moreover, a positive association was reported between authors' research performance and centrality and structural hole measures in t3 as opposed to ego-density, constraint and tie strength in t1. The findings can be used by policy makers to improve collaboration and develop research programs that can enhance several scientific fields. Central authors identified in the networks are better positioned to receive government funding, maximize research outputs and improve research community reputation. Viewed from a network's perspective, scientists can understand how collaborative relationships influence research performance and consider where to invest their decision and choices

    Experimental correlation of natural convection losses from a scale-model solar cavity receiver with non-isothermal surface temperature distribution

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    Correlations for natural convection heat loss from solar cavity receivers are widely based on isothermal surface temperature assumptions, which do not occur in practice due to the local heat balance varying with position. An open question thus exists regarding the suitability of such correlations for non-isothermal conditions. This paper addresses this issue by presenting a new Nusselt correlation developed from an experimental investigation of natural convection heat loss from a non-isothermal scale-model cylindrical cavity receiver. Cavities that are considered in this work have length-to-diameter ratios of 1 and 2, are operated at peak temperatures ranging from 355 °C to 650 °C, and exhibit temperature differences along the cavity wall between 40 °C and 342 °C. Stagnation and convection zones, as well as view factor profiles, are observed to contribute to the wall temperature distribution as the cavity is inclined downwards. An energy balance undertaken for steady state provides insight into the effects of non-uniform surface temperature distribution and inclination-dependent surface areas on radiative and convective losses. Natural convection heat loss results from this work are compared with widely-used correlations from the literature that assume isothermal wall conditions, and systematic discrepancies are observed. The proposed Nusselt correlation which accounts for the temperature non-uniformity, cavity inclination and geometric aspect ratio is evaluated against experimental data from this and other studies. It is found to produce excellent predictions of Nusselt numbers for cylindrical cavity receivers in the Grashof number range of 2.6 × 105 to 1.4 × 107

    Improved model for the analysis of air fluorescence induced by electrons

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    A model recently proposed for the calculation of air-fluorescence yield excited by electrons is revisited. Improved energy distributions of secondary electrons and a more realistic Monte Carlo simulation including some additional processes have allowed us to obtain more accurate results. The model is used to study in detail the relationship between fluorescence intensity and deposited energy in a wide range of primary energy (keVs - GeVs). In addition, predictions on the absolute value of the fluorescence efficiency in the absence of collisional quenching will be presented and compared with available experimental data.Comment: Contribution to the 5th Fluorescence Workshop, El Escorial, Madrid, Spain, September 2007, to appear in Nuclear Instruments and Methods A. Revised version.- More details on the comparison with experimental dat

    Aplicações da aproximação quase-newtoniana da Relatividade Geral a problemas em astrofísica

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    Dissertação de Mestrado apresentada ao Programa de Pós- Graduação em Fı́sica Aplicada da Universidade Federal da Integração Latino-Americana (PPGFISA-UNILA) como parte dos requisitos ncessários para obtenção do tı́tulo de Mestre em (Fı́sica). Orientador: Prof. Dr. Abraão Jessé Capistrano de Souza Coorientador: Prof. Dr. Luı́s Antonio CabralNo presente trabalho, investigamos o movimento lento na Relatividade Geral (RG) sob ação de um campo gravitacional arbitrário. Trata-se do uso de uma aproximação conhecida por aproximação quase Newtoniana (NNA). Nossa intenção é apresentar um novo paradigma para a Astrofísica, uma vez que o modelo pode auxiliar no entendimento da gravidade na cinemática e dinâmica de corpos celestes, mas não representa uma modificação da RG. Primeiro, usamos a métrica de Weyl para analisar o desvio do periastro de 34 exoplanetas. Em segundo lugar, a métrica oblata de Zipoy, em termos da solução do monopólo, também, faz parte do escopo deste trabalho. Mostramos que a métrica de Zipoy pode ser muito útil para propósitos astrofísicos, mesmo quando comparada a solução padrão de Einstein ou via formalismo pós-newtoniano parametrizado (PPN), porque satisfaz o valor da precessão observada para o periélio de Mercúrio, a solução fornece órbitas elípticas e, também, permite o estudo de precessões retrógradas.In the present work, we investigate the slow motion in General Relativity (GR) under an arbitrary gravitational field. It is about the use of an approximation known by nearly Newtonian approximation (NNA). Our intent is to present a new paradigm for Astrophy- sics, since the model can assist the understanding of gravity in kinematic and dynamics of celestial bodies but does not represent a modification of GR. First, we use Weyl’s me- tric to analyze the deviation of periastron of 34 exoplanets. Secondly, the oblate Zipoy’s metric, in terms by monopole solution, is also part of the scope of this work. We show that Zipoy’s metric may be very useful for astrophysical purposes, even when compared to Einstein’s standard solution or by formalism of parameterized post-Newtonian (PPN), because it satisfies the observed precession value for Mercury’s perihelion, the solution provides elliptical orbits and also allows the study of retrograde precessio
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