476 research outputs found

    The anatomy of the human thyroid veins and its surgical application

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    The present study was motivated by the importance of the thyroid veins in surgery in the anterolateral cervical region, particularly in tracheostomies, the need for information on modern diagnostic imaging techniques and the lack of specific publications on the subject. The research was performed on 30 adult human specimens by means of dissection and measurement. The superior thyroid vein was constant, single on both sides (83.3%), with its termination (87.1%) at the internal jugular vein (97.2%), either isolated (29.4%) or with other veins, mostly the lingual vein (52.1%), and was located between 1.0 and 2.5 cm below a plane that passes the upper margin of the hyoid bone. The medial thyroid vein, when present, was not constant (43.3%), was single (96.1%), terminated in the internal jugular vein and was located between 2.0 and 4.0 cm from the mid-sagittal line (84.6%). The inferior thyroid vein was constant (96.7%) and varied in number, with one (62.1%), two (27.6%) or even five occurring, and was formed by the confluence of two primary branches (78.6%) as a result of the abundance of anastomoses coming from the lower and medial parts of the gland. The number of terminations corresponded to the number of veins, at the level of the 5th to 8th rings in 36.9%, of the 9th to 10th rings in 34.8% and of the 11th to 14th rings in 28.3%, and occurred in the right brachiocephalic vein (26.1%), in the left brachiocephalic vein (60.9%) or in both veins (13.0%)

    Inclusive electron scattering in a relativistic Green function approach

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    A relativistic Green function approach to the inclusive quasielastic (e,e') scattering is presented. The single particle Green function is expanded in terms of the eigenfunctions of the nonhermitian optical potential. This allows one to treat final state interactions consistently in the inclusive and in the exclusive reactions. Numerical results for the response functions and the cross sections for different target nuclei and in a wide range of kinematics are presented and discussed in comparison with experimental data.Comment: 12 pages, 7 figures, REVTeX

    Core Body Temperatures in Intermittent Sports: A Systematic Review

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    Background: Hyperthermia (and associated health and performance implications) can be a significant problem for athletes and teams involved in intermittent sports. Quantifying the highest thermal strain (i.e. peak core body temperature [peak T c]) from a range of intermittent sports would enhance our understanding of the thermal requirements of sport and assist in making informed decisions about training or match-day interventions to reduce thermally induced harm and/or performance decline. Objective: The objective of this systematic review was to synthesise and characterise the available thermal strain data collected in competition from intermittent sport athletes. Methods: A systematic literature search was performed on Web of Science, MEDLINE, and SPORTDiscus to identify studies up to 17 April 2023. Electronic databases were searched using a text mining method to provide a partially automated and systematic search strategy retrieving terms related to core body temperature measurement and intermittent sport. Records were eligible if they included core body temperature measurement during competition, without experimental intervention that may influence thermal strain (e.g. cooling), in healthy, adult, intermittent sport athletes at any level. Due to the lack of an available tool that specifically includes potential sources of bias for physiological responses in descriptive studies, a methodological evaluation checklist was developed and used to document important methodological considerations. Data were not meta-analysed given the methodological heterogeneity between studies and therefore were presented descriptively in tabular and graphical format. Results: A total of 34 studies were selected for review; 27 were observational, 5 were experimental (2 parallel group and 3 repeated measures randomised controlled trials), and 2 were quasi-experimental (1 parallel group and 1 repeated measures non-randomised controlled trial). Across all included studies, 386 participants (plus participant numbers not reported in two studies) were recruited after accounting for shared data between studies. A total of 4 studies (~ 12%) found no evidence of hyperthermia, 24 (~ 71%) found evidence of ‘modest’ hyperthermia (peak T c between 38.5 and 39.5 °C), and 6 (~ 18%) found evidence of ‘marked’ hyperthermia (peak T c of 39.5 °C or greater) during intermittent sports competition. Conclusions: Practitioners and coaches supporting intermittent sport athletes are justified to seek interventions aimed at mitigating the high heat strain observed in competition. More research is required to determine the most effective interventions for this population that are practically viable in intermittent sports settings (often constrained by many competing demands). Greater statistical power and homogeneity among studies are required to quantify the independent effects of wet bulb globe temperature, competition duration, sport and level of competition on peak T c, all of which are likely to be key modulators of the thermal strain experienced by competing athletes. Registration: This systematic review was registered on the Open Science Framework (https://osf.io/vfb4s ; https://doi.org/10.17605/OSF.IO/EZYFA , 4 January 2021).Open Access funding enabled and organized by CAUL and its Member Institutions. Mitchell Henderson is supported by the Australian Government’s Research Training Program scholarship

    B-parameters for DeltaS = 2 Supersymmetric Operators

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    We present a calculation of the matrix elements of the most general set of DeltaS=2 dimension-six four-fermion operators. The values of the matrix elements are given in terms of the corresponding B-parameters. Our results can be used in many phenomenological applications, since the operators considered here give important contributions to K^0--K^0bar mixing in several extensions of the Standard Model (supersymmetry, left-right symmetric models, multi-Higgs models etc.). The determination of the matrix elements improves the accuracy of the phenomenological analyses intended to put bounds on basic parameters of the different models, as for example the pattern of the sfermion mass matrices. The calculation has been performed on the lattice, using the tree-level improved Clover action at two different values of the strong coupling constant (beta=6/g_0^2(a)=6.0 and 6.2, corresponding to a^-1= 2.1 and 2.7 GeV respectively), in the quenched approximation. The renormalization constants and mixing coefficients of the lattice operators have been obtained non-perturbatively.Comment: Comparison with results of ref.[22] added in sect. 4; updated ref.[7

    IL-4-secreting CD4+ T cells are crucial to the development of CD8+ T-cell responses against malaria liver stages.

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    CD4+ T cells are crucial to the development of CD8+ T cell responses against hepatocytes infected with malaria parasites. In the absence of CD4+ T cells, CD8+ T cells initiate a seemingly normal differentiation and proliferation during the first few days after immunization. However, this response fails to develop further and is reduced by more than 90%, compared to that observed in the presence of CD4+ T cells. We report here that interleukin-4 (IL-4) secreted by CD4+ T cells is essential to the full development of this CD8+ T cell response. This is the first demonstration that IL-4 is a mediator of CD4/CD8 cross-talk leading to the development of immunity against an infectious pathogen

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    In the last years many populations of anurans have declined and extinctions have been recorded. They were related to environmental pollution, changes of land use and emerging diseases. The main objective of this study was to determine copper sensitivity of the anuran of the Amazon Rhinella granulosa and Scinax ruber tadpoles at stage 25 and Scinax ruber eggs exposed for 96 h to copper concentrations ranging from 15 µg Cu L-1 to 94 µg Cu L-1. LC50 at 96 h of Rhinella granulosa Gosner 25, Scinax ruber Gosner 25 and Scinax ruber eggs in black water of the Amazon were 23.48, 36.37 and 50.02 µg Cu L-1, respectively. The Biotic Ligand Model was used to predict the LC50 values for these species and it can be considered a promising tool for these tropical species and water conditions. Copper toxicity depends on water physical-chemical composition and on the larval stage of the tadpoles. The Gosner stage 19-21 (related to the appearance of external gills) is the most vulnerable and the egg stage is the most resistant. In case of contamination by copper, the natural streams must have special attention, since copper is more bioavailable.Nos últimos anos foram registrados muitas extinções e declínios de populações de anuros. Eles estavam relacionados com a poluição do ambiente, a mudanças no uso da terra e ao surgimento de doenças. O principal objetivo deste estudo foi determinar a sensibilidade dos anuros amazônicos ao cobre. Os girinos de Scinax ruber e Rhinella granulosa no estadio 25 e os ovos de Scinax ruber foram expostos por 96 horas a concentrações de cobre entre 15 µg Cu L-1 a 94 µg Cu L-1. A CL50 -96 h dos girinos de Rhinella granulosa, dos girinos de Scinax ruber e dos ovos de Scinax ruber em águas pretas da Amazônia foram 23,48; 36,37 e 50,02 µg Cu L-1, respectivamente. O modelo do ligante biótico foi usado para prever os valores de CL50 para essas duas espécies e pode ser considerado uma ferramenta promissora para essas espécies tropicais e para essas condições de água. A Toxicidade de cobre depende da composição físico-química da água e do estagio larval dos girinos. O estadio 19-21 de Gosner (relacionados ao aparecimento das brânquias externas) são os mais vulnerável e o estagio de ovo é o mais resistente. Em caso de contaminação por cobre, os igarapés naturais devem ter uma atenção especial, uma vez que o cobre é mais biodisponível nesse ambiente

    Quark Masses from Lattice QCD at the Next-to-Leading Order

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    Using the results of several quenched lattice simulations, we predict the value of the strange and charm quark masses in the continuum at the next-to-leading order, msMS‾(μ=2  GeV)=(127±18)  MeVm^{\overline{MS}}_s(\mu=2\,\, \rm{GeV})= (127 \pm 18)\,\, \rm{MeV} and mchMS‾(μ=2  GeV)=(1.47±0.28)  GeVm^{\overline{MS}}_{ch}(\mu=2 \,\,\rm{GeV})=(1.47 \pm 0.28)\,\, \rm{GeV}. The errors quoted above have been estimated by taking into account the original statistical error of the lattice results and the uncertainties coming from the matching of the lattice to the continuum theory. A detailed presentation of the relevant formulae at the next-to-leading order and a discussion of the main sources of errors is also presented.Comment: 26 pages (2 postscript file included), LaTeX, CERN-TH.7256/94, ROME prep. 94/101

    How to move ionized gas: an introduction to the dynamics of HII regions

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    This review covers the dynamic processes that are important in the evolution and structure of galactic HII regions, concentrating on an elementary presentation of the physical concepts and recent numerical simulations of HII region evolution in a non-uniform medium. The contents are as follows: (1) The equations (Euler equations; Radiative transfer; Rate equations; How to avoid the dynamics; How to avoid the atomic physics). (2) Physical concepts (Static photoionization equilibrium; Ionization front propagation; Structure of a D-type front; Photoablation flows; Other ingredients - Stellar winds, Radiation pressure, Magnetic fields, Instabilities). (3) HII region evolution (Early phases: hypercompact and ultracompact regions; Later phases: compact and extended regions; Clumps and turbulence).Comment: To be published as a chapter in 'Diffuse Matter from Star Forming Regions to Active Galaxies' - A volume Honouring John Dyson. Eds. T. W. Harquist, J. M. Pittard and S. A. E. G. Falle. 25 pages, 7 figures. Some figures degraded to meet size restriction. Full-resolution version available at http://www.ifront.org/wiki/Dyson_Festschrift_Chapte
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