Statistical contributions

Publisher Copyright: © 2022 Author(s).Border officers of Lisbon airport (Portugal) are, as professionals from other sectors of activity, exposed to various psychosocial stressors in their workplace. Thus, monitoring the professionals of this security service is important to understand their situation, because working under conditions of prolonged excessive stress (distress) can lead to burnout syndrome, with negative consequences for workers, organization and economy. In this study a Portuguese version of the Shirom-Melamed Burnout Measure (SMBM), validated internationally, was used in a survey to assess the "feeling of burnout"of those workers. The SMBM has 14 questions that correspond to manifest variables expressed in a Likert-type scale of 7 categories, which operationalize the latent variables: emotional exhaustion, cognitive fatigue (or weariness) and physical fatigue, considered three facets of burnout. Based on a sample, some descriptive statistics were obtained, and to compare the latent variables mentioned in two groups of workers, created by the dichotomous variable years of service (A: maximum 2 years and B: more than 2 years), a parametric test was applied, with and without outliers. The means of the scores of the three latent variables are less than 5 and the same happens with the latent variable feeling of burnout (which may be indicative of the absence of problems in this domain). In the comparison of groups A and B, for a significance level of 5%, only when considering the results with the full dataset (i.e. with outliers) were identified statistically significant differences were identified in the means of the scores of latent variables emotional exhaustion and feeling of burnout.publishersversionpublishe

Semiclassical back reaction around a cosmic dislocation

The energy-momentum vacuum average of a conformally coupled massless scalar field vibrating around a cosmic dislocation (a cosmic string with a dislocation along its axis) is taken as source of the linearized semiclassical Einstein equations. The solution up to first order in the Planck constant is derived. Motion of a test particle is then discussed, showing that under certain circumstances a helical-like dragging effect, with no classical analogue around the cosmic dislocation, is induced by back reaction.Comment: Published version, 4 pages, no figures, REVTeX4 fil

LIQUID METAL FLOW CONTROL BY DC ELECTROMAGNETIC PUMPS

The cooling system of high-density thermal power requires fluids of high thermal conductivity, such as liquid metals. Electromagnetic pumps can be used to liquid metal fluid flow control in cooling circuits. The operation of electromagnetic pumps used to flow control is based on Lorentz force. This force can be achieved by magnetic field and electric current interaction, controlled by external independent power supplies. This work presents the electromagnetic pump operational principles, the IEAv development scheme and the BEMC-1 simulation code. The theoretical results of BEMC-1simulation are compared to electromagnetic pump operation experimental data, validating the BEMC-1 code. This code is used to evaluate the DC electromagnetic pump performance applied to Mercury flow control and others liquid metal such as Sodium, Lead and Bismuth, used in nuclear fast reactors

A PARAMETRIC STUDY AND PERFORMANCE EVALUATION OF DC ELECTROMAGNETIC PUMPS WITH BEMC-1 CODE

Electromagnetic pumps are used to control liquid metal fluid flow in cooling loops. The principle of operation of an electromagnetic pump is based on Lorentz’s force. This is obtained by interaction of the magnetic field and the electrical current, imposed and adjusted by independent external electric power sources. In this work are presented the continuous current electromagnetic pumps, their basic equations and the BEMC-1 code, developed for design and performance evaluation of a DC electromagnetic pump. The main objective of this paper is a parametric study for magnetic induction, static pressure, fluid flow and performance evaluation of the pump. The theoretical results are compared with the experimental data to get adjust factors to be used in the BEMC-1 code. In this way the BEMC-1 code can be validated and used in the evaluations and projects of DC electromagnetic pumps

Distal Forearm Replantation Rehabilitation - Case Review

Actualmente, o desafio da reimplantação do membro superior pós-amputação tornou-se uma realidade alcançável e minuciosamente aperfeiçoada nas últimas décadas, e em permanente evolução. A opção cirúrgica de reimplantação deve ter em conta não apenas a análise exclusiva da viabilidade do reimplante, mas, fundamentalmente o seu potencial de recuperação funcional a longo prazo. Apresenta-se o caso clínico de um jovem de 18 anos, fumador, transferido do Hospital do Barreiro, vítima de acidente de trabalho, com traumatismo por corte, do qual resultou amputação distal do antebraço direito. O tempo de isquemia quente foi de 4horas, tendo sido submetido a cirurgia de reimplantação conjunta por Ortopedia e Cirurgia Plástica e Reconstrutiva (CPR) para reimplantação. Na sequência da cirurgia, foi precocemente referenciado a Medicina Física e de Reabilitação (MFR), realizando um programa de reabilitação funcional sequencial. Este trabalho visa enfatizar a importância do papel da MFR num precoce, criterioso e extenso programa de reabilitação, factor fundamental na recuperação funcional e prognóstico a longo prazo destas lesões e prevenção de complicações

Comparative study of NiTi orthodontic wires

In this study, two superelastic NiTi orthodontic wires (0.46 x 0.64 mm(2)) were analyzed. The determination of phase transformation temperatures along with the identification of the predominant phase at room and intraoral temperatures were accomplished by DSC analysis. Superelastic behavior was analyzed through tensile tests. 3-point bending tests were performed on a model design which included brackets to compare wires' behavior: lower forces corresponding to Ormco wires' reverse phase transformation plateau when compared to Dentaurum were exhibited. Wire slippage inside the brackets and friction caused by wire-bracket-ligature combinations on bending and pulling tests, respectively, are also discussed. (C) 2014 The Authors. Published by Elsevier Ltd.publishersversionpublishe

Crescimento e incremento de Sequoia sempervirens (D. Don) Endl., São Joaquim, SC.

O presente trabalho teve como objetivo estudar a forma de crescimento e calcular o incremento médio e corrente anual das variáveis dendrométricas de Sequoia sempervirens, de mudas originárias dos EUA e cultivadas no campo experimental da EPAGRI em São Joaquim, SC. Para isso, ajustou-se e selecionou-se um entre modelos lineares e não lineares que se mostraram eficientes, permitindo identificar as formas do crescimento de acordo com a idade. Os resultados obtidos demonstram que aos 18 anos o incremento médio anual em altura foi de 0,55 m/árvore/ano e o incremento médio em volume foi de 0,76 m3/árvore/ano, indicando um ótimo potencial de crescimento. Para volume e diâmetro a equação selecionada foi de Schumacker com R2aj. de 0,9558 e Syx de 0,7 cm para diâmetro, e para volume R2aj. de 0,9421 e Syx de 0,8694 m3, para a variável altura o modelo selecionado foi de Chapman-Richards com R2aj. de 0,98 e Syx de 0,5364 m. Os resultados demonstraram que a espécie teve um incremento médio em diâmetro de 2,5 cm na região, semelhante aos plantios comerciais de pinus, com ponto de rotação técnica em volume aos 70 anos, podendo ser cultivada comercialmente

Strategy to improve the residual diametric structure of Cedrela odorata for a new cutting cycle.

IUFROLAT 2013. Disponibilizado online. Resumen

Necrotic neurons enhance microglial neurotoxicity through induction of glutaminase by a MyD88-dependent pathway

<p>Abstract</p> <p>Background</p> <p>Microglia are macrophage-like cells that constantly sense the microenvironment within the central nervous system (CNS). In the event of neuronal stress or injury, microglial cells rapidly react and change their phenotype. This response may lead to a deleterious type of microglial activation, which is often associated with neuroinflammation and neurotoxicity in several neuropathological conditions. We investigated the molecular mechanisms underlying triggering of microglial activation by necrotic neuronal damage.</p> <p>Methods</p> <p>Primary cultures of microglia were used to study the effect of necrotic neurons on microglial inflammatory responses and toxicity towards cerebellar granule neurons (CGN). The mouse hippocampal cell line, HT22, was used in this study as the main source of necrotic neurons to stimulate microglia. To identify the signal transduction pathways activated in microglia, primary microglial cultures were obtained from mice deficient in Toll-like receptor (TLR) -2, -4, or in the TLR adapter protein MyD88.</p> <p>Results</p> <p>Necrotic neurons, but not other necrotic cell types, induced microglial activation which was characterized by up-regulation of: i) MHC class II; ii) co-stimulatory molecules, i.e. CD40 and CD24; iii) β2 integrin CD11b; iii) pro-inflammatory cytokines, i.e. interleukin 6 (IL-6), IL-12p40 and tumor-necrosis factor (TNF); iv) pro-inflammatory enzymes such as nitric oxide synthase (iNOS, type II NOS), indoleamine 2,3-dioxygenase (IDO) and cyclooxygenase-2 (COX-2) and increased microglial motility. Moreover, microglia-conditioned medium (MCM) obtained from cultures of activated microglia showed increased neurotoxicity mediated through the <it>N</it>-methyl-D-aspartate receptor (NMDAR). The activation of microglia by necrotic neurons was shown to be dependent on the TLR-associated adapter molecule myeloid differentiation primary response gene (<it>MyD88</it>). Furthermore, MyD88 mediated enhanced neurotoxicity by activated microglia through up-regulation of the expression and activity of glutaminase, an enzyme that produces glutamate, which is an NMDAR agonist.</p> <p>Conclusion</p> <p>These results show that necrotic neurons activate in microglia a MyD88-dependent pathway responsible for a pro-inflammatory response that also leads to increased neurotoxic activity through induction of glutaminase. This finding contributes to better understanding the mechanisms causing increased neuroinflammation and microglial neurotoxicity in a neurodegenerative environment.</p