2,593 research outputs found

    Long-term perturbations due to a disturbing body in elliptic inclined orbit

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    In the current study, a double-averaged analytical model including the action of the perturbing body's inclination is developed to study third-body perturbations. The disturbing function is expanded in the form of Legendre polynomials truncated up to the second-order term, and then is averaged over the periods of the spacecraft and the perturbing body. The efficiency of the double-averaged algorithm is verified with the full elliptic restricted three-body model. Comparisons with the previous study for a lunar satellite perturbed by Earth are presented to measure the effect of the perturbing body's inclination, and illustrate that the lunar obliquity with the value 6.68\degree is important for the mean motion of a lunar satellite. The application to the Mars-Sun system is shown to prove the validity of the double-averaged model. It can be seen that the algorithm is effective to predict the long-term behavior of a high-altitude Martian spacecraft perturbed by Sun. The double-averaged model presented in this paper is also applicable to other celestial systems.Comment: 28 pages, 6 figure

    Forecasting temporal dynamics of cutaneous leishmaniasis in Northeast Brazil.

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    IntroductionCutaneous leishmaniasis (CL) is a vector-borne disease of increasing importance in northeastern Brazil. It is known that sandflies, which spread the causative parasites, have weather-dependent population dynamics. Routinely-gathered weather data may be useful for anticipating disease risk and planning interventions.Methodology/principal findingsWe fit time series models using meteorological covariates to predict CL cases in a rural region of Bahía, Brazil from 1994 to 2004. We used the models to forecast CL cases for the period 2005 to 2008. Models accounting for meteorological predictors reduced mean squared error in one, two, and three month-ahead forecasts by up to 16% relative to forecasts from a null model accounting only for temporal autocorrelation.SignificanceThese outcomes suggest CL risk in northeastern Brazil might be partially dependent on weather. Responses to forecasted CL epidemics may include bolstering clinical capacity and disease surveillance in at-risk areas. Ecological mechanisms by which weather influences CL risk merit future research attention as public health intervention targets

    Streptococcus pyogenes Meningitis in a Pediatric Patient: Case Report

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    Streptococcus pyogenes causes a wide spectrum of diseases in children. However, meningitis due to this pathogen is highly uncommon. Although rare, it is associated with a high case fatality rate and can result in severe neurological sequelae. We report a case of Streptococcus pyogenes meningitis in a previously healthy 3-year-old boy. The purpose of this case report is to emphasize that this agent should be considered a cause of meningitis in previously healthy infants because of its frequent association with complications, sequelae, and high mortality rates

    Avaliação Psicológica de Jovens com Comportamentos Desviantes

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    A avaliação psicológica constitui sempre um processo complexo e que deve atender às especificidades inerentes ao indivíduo, ao grupo ou à comunidade. Assim, não se verificam exceções no que respeita às populações com exteriorização de condutas desviantes e, dentro deste grupo muito alargado, devem ainda ser consideradas as especificidades subjacentes ao tipo de comportamento e ao contexto da sua manifestação. Propomos um plano/roteiro de avaliação voltado para jovens com comportamentos desviantes, com maior ou menor flexibilidade no seguimento dos procedimentos aconselhados, sempre em função das características do alvo de avaliação. Tendo por base a revisão da literatura e a experiência adquirida no âmbito do trabalho desenvolvido pelo Grupo de Consumos e Delinquências (GCD), da Clínica Pedagógica de Psicologia (CPP) da Universidade Fernando Pessoa (UFP), delineámos um protocolo de avaliação, com o objetivo de nortear o conjunto de procedimentos, aquando da avaliação de jovens com sinalização de problemas comportamentais. Trata-se de uma proposta que procura abarcar uma vertente mais impressionista, em que se analisam aspetos mais subjetivos, apelando a técnicas como a observação e a entrevista, não deixando escapar os aspetos mais objetivos, através do recurso a técnicas e a instrumentos mais estruturados.

    Composição química de plantas de cobertura como indicador de emissão de N2O.

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    A versão atual do Guia para Elaboração de Inventários Nacionais de Emissões de Gases de Efeito Estufa do IPCC adicionou a quantificação da contribuição de emissões de N2O em decorrência da decomposição de resíduos vegetais no cálculo do fator de emissão de óxido nitroso. Assim, este trabalho teve como objetivo analisar parâmetros (lignina, celulose, hemiceluloses, N) relacionados ao processo de decomposição de plantas de cobertura indicadores do potencial de emissão de N2O em sistema plantio direto no Cerrado. As seguintes espécies vegetais foram analisadas quanto aos teores de lignina, FDA, FDN, N total e conteúdo de N: Canavalia brasiliensis; Cajanus cajan; Mucuna aterrima; Crotalaria juncea; Pennisetum glaucum; Sorgum bicholor; Brachiaria ruziziensis;Triticum aestivum, Raphanus sativus e vegetação espontânea. Os menores teores de lignina foram observados em tecido vegetal de Brachiaria ruziziensis, Pennisetum glaucum e Canavalia brasiliensis e os conteúdos de N mais elevados em Canavalia brasiliensis. Porém, o tecido vegetal de Pennisetum glaucum possui maior C:N. Assim, a qualidade dos resíduos vegetais de Brachiaria ruziziensis e Canavalia brasiliensis, que apresentam decomposição acelerada e elevada concentração de N, pode favorecer mineralização de nitrogênio, consequentemente, as emissões de N2O para atmosfera

    O157:H7 Shiga Toxin-Producing Escherichia coli Strains Associated with Sporadic Cases of Diarrhea in São Paulo, Brazil

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    Inst Adolfo Lutz Registro, Sao Paulo, BrazilLab Anal Clin Dr Joao Antonio Vozza, Campinas, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Sao Paulo, BrazilWeb of Scienc

    Compensatory T-Cell Regulation in Unaffected Relatives of SLE Patients, and Opposite IL-2/CD25-Mediated Effects Suggested by Coreferentiality Modeling

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    In human systemic lupus erythematosus (SLE), diverse autoantibodies accumulate over years before disease manifestation. Unaffected relatives of SLE patients frequently share a sustained production of autoantibodies with indiscriminable specificity, usually without ever acquiring the disease. We studied relations of IgG autoantibody profiles and peripheral blood activated regulatory T-cells (aTregs), represented by CD4+CD25bright T-cells that were regularly 70–90% Foxp3+. We found consistent positive correlations of broad-range as well as specific SLE-associated IgG with aTreg frequencies within unaffected relatives, but not patients or unrelated controls. Our interpretation: unaffected relatives with shared genetic factors compensated pathogenic effects by aTregs engaged in parallel with the individual autoantibody production. To study this further, we applied a novel analytic approach named coreferentiality that tests the indirect relatedness of parameters in respect to multivariate phenotype data. Results show that independently of their direct correlation, aTreg frequencies and specific SLE-associated IgG were likely functionally related in unaffected relatives: they significantly parallelled each other in their relations to broad-range immunoblot autoantibody profiles. In unaffected relatives, we also found coreferential effects of genetic variation in the loci encoding IL-2 and CD25. A model of CD25 functional genetic effects constructed by coreferentiality maximization suggests that IL-2-CD25 interaction, likely stimulating aTregs in unaffected relatives, had an opposed effect in SLE patients, presumably triggering primarily T-effector cells in this group. Coreferentiality modeling as we do it here could also be useful in other contexts, particularly to explore combined functional genetic effects

    UK research data resources based on primary care electronic health records: review and summary for potential users

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    BACKGROUND: The range and scope of electronic health record (EHR) data assets in the UK has recently increased, which has been mainly in response to the COVID-19 pandemic. Summarising and comparing the large primary care resources will help researchers to choose the data resources most suited to their needs. AIM: To describe the current landscape of UK EHR databases and considerations of access and use of these resources relevant to researchers. DESIGN & SETTING: Narrative review of EHR databases in the UK. METHOD: Information was collected from the Health Data Research Innovation Gateway, publicly available websites and other published data, and from key informants. The eligibility criteria were population-based open-access databases sampling EHRs across the whole population of one or more countries in the UK. Published database characteristics were extracted and summarised, and these were corroborated with resource providers. Results were synthesised narratively. RESULTS: Nine large national primary care EHR data resources were identified and summarised. These resources are enhanced by linkage to other administrative data to a varying extent. Resources are mainly intended to support observational research, although some can support experimental studies. There is considerable overlap of populations covered. While all resources are accessible to bona fide researchers, access mechanisms, costs, timescales, and other considerations vary across databases. CONCLUSION: Researchers are currently able to access primary care EHR data from several sources. Choice of data resource is likely to be driven by project needs and access considerations. The landscape of data resources based on primary care EHRs in the UK continues to evolve

    Low frequency of CD4+CD25+ Treg in SLE patients: a heritable trait associated with CTLA4 and TGFβ gene variants

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    <p>Abstract</p> <p>Background</p> <p>CD4<sup>+</sup>CD25<sup>+ </sup>regulatory T cells play an essential role in maintaining immune homeostasis and preventing autoimmunity. Therefore, defects in Treg development, maintenance or function have been associated with several human autoimmune diseases including Systemic Lupus Erythematosus (SLE), a systemic autoimmune disease characterized by loss of tolerance to nuclear components and significantly more frequent in females.</p> <p>Results</p> <p>To investigate the involvement of Treg in SLE pathogenesis, we determined the frequency of CD4<sup>+</sup>CD25<sup>+</sup>CD45RO<sup>+ </sup>T cells, which encompass the majority of Treg activity, in the PBMC of 148 SLE patients (76 patients were part of 54 families), 166 relatives and 117 controls. SLE patients and their relatives were recruited in several Portuguese hospitals and through the Portuguese Lupus Association. Control individuals were blood donors recruited from several regional blood donor centers. Treg frequency was significantly lower in SLE patients than healthy controls (z = -6.161, <it>P </it>< 0.00001) and intermediate in the relatives' group. Remarkably, this T cell subset was also lower in females, most strikingly in the control population (z = 4.121, <it>P </it>< 0.001). We further ascertained that the decreased frequency of Treg in SLE patients resulted from the specific reduction of <it>bona fide </it>FOXP3<sup>+</sup>CD4<sup>+</sup>CD25<sup>+ </sup>Treg. Treg frequency was negatively correlated with SLE activity index (SLEDAI) and titers of serum anti-dsDNA antibodies. Both Treg frequency and disease activity were modulated by IVIg treatment in a documented SLE case. The segregation of Treg frequency within the SLE families was indicative of a genetic trait. Candidate gene analysis revealed that specific variants of <it>CTLA4 </it>and <it>TGFβ </it>were associated with the decreased frequency of Treg in PBMC, while <it>FOXP3 </it>gene variants were associated with affection status, but not with Treg frequency.</p> <p>Conclusion</p> <p>SLE patients have impaired Treg production or maintenance, a trait strongly associated with SLE disease activity and autoantibody titers, and possibly resulting from the inability to convert FOXP3<sup>+</sup>CD25<sup>- </sup>into FOXP3<sup>+</sup>CD25<sup>+ </sup>T cells. Treg frequency is highly heritable within SLE families, with specific variants of the <it>CTLA4 </it>and <it>TGFβ </it>genes contributing to this trait, while <it>FOXP3 </it>contributes to SLE through mechanisms not involving a modulation of Treg frequency. These findings establish that the genetic components in SLE pathogenesis include genes related to Treg generation or maintenance.</p
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