317 research outputs found

    pi-/pi+ ratio in heavy ions collisions: Coulomb effect or chemical equilibration?

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    We calculate the pi-/pi+ ratio for Pb+Pb at CERN/SPS energies and for Au+Au at BNL/AGS energies using a (3+1) dimensional hydrodynamical model. Without consideration of Coulomb effect an enhancement of this ratio at low mt is found compatible with that observed in these experiments. Our calculations are based on previous (3+1) dimensional hydrodynamical simulations (HYLANDER), which described many other aspects of experimental data. In this model the observed enhancement is a consequence of baryon and strangeness conservation and of chemical equilibration of the system and is caused by the decay of produced hyperons, which leads to a difference in the total number of positive and negative pions as well. Based on the same approach, we also present results for the pi-/pi+ ratio for S+S (CERN/SPS) collisions, where we find a similar effect. The absence of the enhancement of the pi-/pi+ ratio in the S+S data presented by the NA44 Collaboration, if confirmed, could indicate that chemical equilibration has not yet been estabilished in this reaction.Comment: 8 pages and 2 figures, submmited to Phys. Lett. B. This reviewed version (Nov.29,1996) contains more details about the model simulated efficiency considering the experimental detection conditions. Other small modifications were mad

    Higher Order Bose-Einstein Correlations test the Gaussian Density Matrix Approach

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    A multiparticle system produced by a large number of independent sources is described by a gaussian density matrix W. All theoretical approach to Bose-Einstein Correlatios Cn in high energy physics use this form for W. One of the most salient consequences of this form is the fact that all higher order (n>2) moments of the current distribution can be expressed in terms of the first two. We test this property by comparing the data on C2(Q^2), C3(Q^2) and C4(Q^2) from pion-p and K-p reactions at 250 GeV/c with the predictions of a general quantum statistical space-time approach. Even a simplified version of such approach can account for the data. Previous attempts along these lines, which did not use the space-time approach, met with difficulties.Comment: 17 pages (including one Table) and 2 figures. To appear in Physics Letters B (PLB 13397

    Effect of air pollution on diabetes and cardiovascular diseases in São Paulo, Brazil

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    Type 2 diabetes increases the risk of cardiovascular mortality and these patients, even without previous myocardial infarction, run the risk of fatal coronary heart disease similar to non-diabetic patients surviving myocardial infarction. There is evidence showing that particulate matter air pollution is associated with increases in cardiopulmonary morbidity and mortality. The present study was carried out to evaluate the effect of diabetes mellitus on the association of air pollution with cardiovascular emergency room visits in a tertiary referral hospital in the city of São Paulo. Using a time-series approach, and adopting generalized linear Poisson regression models, we assessed the effect of daily variations in PM10, CO, NO2, SO2, and O3 on the daily number of emergency room visits for cardiovascular diseases in diabetic and non-diabetic patients from 2001 to 2003. A semi-parametric smoother (natural spline) was adopted to control long-term trends, linear term seasonal usage and weather variables. In this period, 45,000 cardiovascular emergency room visits were registered. The observed increase in interquartile range within the 2-day moving average of 8.0 µg/m³ SO2 was associated with 7.0% (95%CI: 4.0-11.0) and 20.0% (95%CI: 5.0-44.0) increases in cardiovascular disease emergency room visits by non-diabetic and diabetic groups, respectively. These data indicate that air pollution causes an increase of cardiovascular emergency room visits, and that diabetic patients are extremely susceptible to the adverse effects of air pollution on their health conditions.Disciplina de Clínica Médica, Departamento de MedicinaUniversidade de São Paulo - Laboratório de Poluição Atmosférica Experimental, Faculdade de Medicina, USP (FM-USP

    Modelagem difusa para suporte à decisão na descoberta de SNPs em sequências de cDNA.

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    Diferenças pontuais entre pares de bases de diferentes sequências alinhadas são o tipo mais comum de variabilidade genética. Tais diferenças, conhecidas como polimorfismos de base única (single nucleotide polymorphisms - SNPs), são importantes no estudo davariabilidade das espécies, pois podem provocar alterações funcionais ou fenotípicas, as quais podem implicar em consequências evolutivas ou bioquímicas nos indivíduos das espécies. A descoberta de SNPs por algoritmos computacionais é uma prática bastante difundida e o presente texto apresenta um modelo que se baseia em lógica difusa (fuzzy logic) para, a partir de resultados prévios, auxiliar na tomada de decisão, nos casos em que as informações preliminares sejam divergentes, assim como, na confirmação de informações coincidentes.SBIAgro 2009

    Modelagem difusa para suporte à decisão na descoberta de SNPs em sequências de cDNA.

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    Diferenças pontuais entre pares de bases de diferentes sequências alinhadas são o tipo mais comum de variabilidade genética. Tais diferenças, conhecidas como polimorfismos de base única (single nucleotide polymorphisms – SNPs), são importantes no estudo davariabilidade das espécies, pois podem provocar alterações funcionais ou fenotípicas, as quais podem implicar em consequências evolutivas ou bioquímicas nos indivíduos das espécies. A descoberta de SNPs por algoritmos computacionais é uma prática bastante difundida e o presente texto apresenta um modelo que se baseia em lógica difusa (fuzzy logic) para, a partir de resultados prévios, auxiliar na tomada de decisão, nos casos em que as informações preliminares sejam divergentes, assim como, na confirmação de informações coincidentes

    Programa pedagógico de Medicina intensiva para o internato

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    A Medicina Intensiva desenvolveu-se do avanço de muitas disciplinas clínicas. Seu surgimento vem do reconhecimento de que pacientes graves teriam melhor atendimento caso fossem reunidos em área específica de um hospital, onde seriam assistidos por uma equipe multidisciplinar especializada. A construção desses setores, denominados Unidades de Terapia Intensiva, iniciou-se a partir dos anos 1960. Desta forma surgiu uma especialidade que abrange atitudes e habilidades no reconhecimento do manuseio de pacientes gravemente enfermos, onde se fazem necessárias intervenções terapêuticas imediatas como corolário de raciocínio fisiopatológico e clínico apurados, sendo, portanto, um excelente ambiente de treinamento para o estudante. Por outro lado, a Medicina Intensiva não é contemplada na grade curricular da maioria das Faculdades de Medicina do Brasil, inclusive no UniFOA e os internos desta instituição ao estagiarem na UTI do Hospital Municipal Dr. Munir Rafful o fazem de maneira empírica e sem um direcionamento pedagógico, o que dificulta o processo de ensino-aprendizagem. Portanto o objetivo deste projeto é elaborar um programa teórico-prático em Medicina Intensiva, oferecendo aos alunos uma ferramenta instrucional que tenha impacto na sua formação médica e prática clínica. Pretende-se alcançar este objetivo respaldando-se no princípio da integralidade da assistência ao paciente proposto pelas diretrizes curriculares nacionais para a graduação médica. Obviamente, por se tratar de educação médica, serão revisadas as correntes pedagógicas no ensino da Medicina e a dinâmica da sua mudança: da reforma flexneriana até as estratégicas pedagógicas ativas, onde o aluno é estimulado a pesquisar e se tornar co-responsável por seu aprendizado. Para construção do produto final – o programa em si - utilizar-se-á um questionário com perguntas aos estudantes sobre habilidades (realização de procedimentos em UTI), interesses em lidar com doentes críticos e o impacto que o conhecimento em patologias graves teria em sua formação médica geral. A partir destes dados pretende-se produzir um abrangente programa em Medicina Intensiva com métodos pedagógicos ativos como a aprendizagem baseada em problemas, assim como aulas teóricas convencionais somado à prática na UTI e treinamento de habilidades em manequins

    Thermal photon production in heavy ion collisions

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    Using a three-dimensional hydrodynamic simulation of the collision and an equation of state containing a first order phase transition to the quark-gluon plasma, we study thermal photon production for Au+AuAu+Au collisions at Elab=11.5E_{lab}=11.5 AGeV and for Pb+PbPb+Pb collisions at 160160 AGeV. We obtain surprisingly high rates of thermal photons even at the lower energy, suggesting that, contrary to what was expected so far, photon production may be an interesting topic for experimental search also at the Alternating Gradient Synchrotron. When applied to the reaction S+AuS+Au at 200200 AGeV, our model can reproduce preliminary data obtained by the WA80 Collaboration without having to postulate the existence of an extremely long-lived mixed phase as was recently proposed.Comment: 9 pages, figures are uudecoded compressed and tare

    Livestock IoT: precision livestock management in agribusiness.

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    This paper introduces Livestock IoT (LIoT), a Software Ecosystem (SECO) tailored for precision livestock management within the broader Internet of Things (IoT) concept in agribusiness. In response to the challenges posed by the Fourth Industrial Revolution and the need for enhanced productivity in global food production, the paper highlights the transformative emergence of IoT in elevating precision agribusiness. LIoT is designed to capture, store, and interpret data, providing an integrated platform for intelligent decision-making in animal treatment and automated events. The SECO is structured into five layers, including data streaming, processing, integration, external sources, and visualization, offering a holistic view of information related to confined livestock farming. The paper presents an initial evaluation of the SECO LIoT platform, demonstrating its efficacy in handling compost barn data and supporting decision-making in agriculture. Future work is outlined to optimize the architecture, explore novel applications, and enhance its capacity for supporting emerging technologies in precision livestock contexts.SERP4IoT 2024

    Hydrodynamical analysis of single inclusive spectra and Bose-Einstein correlations for Pb+PbPb+Pb at 160 AGeV

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    We present the first analysis of preliminary data for Pb+PbPb+Pb at 160 AGeVAGeV using 3+1-dimensional relativistic hydrodynamics. We find excellent agreement with the rapidity spectra of negative hadrons and the correlation measurements. The data indicates a large amount of stopping; 65%65\% of the invariant energy of the collision is thermalized and 73%73\% of the baryons are contained in the central fireball. Within our model this implies that a quark-gluon-plasma of lifetime 3.4 fm/cfm/c was formed.Comment: 13 pages, 5 Postscript figures (attached to this file as compressed and uuencoded Postscript file
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