625 research outputs found

    New Spatially Resolved Observations of the T Cha Transition Disk and Constraints on the Previously Claimed Substellar Companion

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    We present multi-epoch non-redundant masking observations of the T Cha transition disk, taken at the VLT and Magellan in H, Ks, and L' bands. T Cha is one of a small number of transition disks that host companion candidates discovered by high-resolution imaging techniques, with a putative companion at a position angle of 78 degrees, separation of 62 mas, and contrast at L' of 5.1 mag. We find comparable binary parameters in our re-reduction of the initial detection images, and similar parameters in the 2011 L', 2013 NaCo L', and 2013 NaCo Ks data sets. We find a close-in companion signal in the 2012 NaCo L' dataset that cannot be explained by orbital motion, and a non-detection in the 2013 MagAO/Clio2 L' data. However, Monte-carlo simulations show that the best fits to the 2012 NaCo and 2013 MagAO/Clio2 followup data may be consistent with noise. There is also a significant probability of false non-detections in both of these data sets. We discuss physical scenarios that could cause the best fits, and argue that previous companion and scattering explanations are inconsistent with the results of the much larger dataset presented here.Comment: 25 pages, 22 figures, accepted for publication in Ap

    Regional variation in life history traits and plastic responses to temperature of the major malaria vector Nyssorhynchus darlingi in Brazil

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    The primary Brazilian malaria vector, Nyssorhynchus darlingi (formerly Anopheles darlingi), ranges from 0°S-23°S across three biomes (Amazonia, Cerrado, Mata Atlântica). Rising temperatures will increase mosquito developmental rates, and models predict future malaria transmission by Ny. darlingi in Brazil will shift southward. We reared F1 Ny. darlingi (progeny of field-collected females from 4 state populations across Brazil) at three temperatures (20, 24, 28 °C) and measured key life-history traits. Our results reveal geographic variation due to both genetic differences among localities and plastic responses to temperature differences. Temperature significantly altered all traits: faster larval development, shorter adult life and overall lifespan, and smaller body sizes were seen at 28 °C versus 20 °C. Low-latitude Amazonia mosquitoes had the fastest larval development at all temperatures, but at 28 °C, average development rate of high-latitude Mata Atlântica mosquitoes was accelerated and equivalent to low-latitude Amazonia. Body size of adult mosquitoes from the Mata Atlântica remained larger at all temperatures. We detected genetic variation in the plastic responses among mosquitoes from different localities, with implications for malaria transmission under climate change. Faster development combined with larger body size, without a tradeoff in adult longevity, suggests vectorial capacities of some Mata Atlântica populations may significantly increase under warming climates.NIH-NIAID [1R01AI110112]; Biodefense and Emerging Infectious Disease training fellowship [T32AI05532901]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Análise molecular dos vírus dengue tipo 1 e 2 no Brasil, baseada nas seqüências da região da junção dos genes do envelope e da proteína não estrutural 1

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    The genomic sequences of the Envelope-Non-Structural protein 1 junction region (E/NS1) of 84 DEN-1 and 22 DEN-2 isolates from Brazil were determined. Most of these strains were isolated in the period from 1995 to 2001 in endemic and regions of recent dengue transmission in São Paulo State. Sequence data for DEN-1 and DEN-2 utilized in phylogenetic and split decomposition analyses also include sequences deposited in GenBank from different regions of Brazil and of the world. Phylogenetic analyses were done using both maximum likelihood and Bayesian approaches. Results for both DEN-1 and DEN-2 data are ambiguous, and support for most tree bipartitions are generally poor, suggesting that E/NS1 region does not contain enough information for recovering phylogenetic relationships among DEN-1 and DEN-2 sequences used in this study. The network graph generated in the split decomposition analysis of DEN-1 does not show evidence of grouping sequences according to country, region and clades. While the network for DEN-2 also shows ambiguities among DEN-2 sequences, it suggests that Brazilian sequences may belong to distinct subtypes of genotype III.Foram determinadas as seqüências nucleotídicas da junção dos genes do envelope e da proteína não estrutural 1 (E/NS1) de 84 cepas de DEN-1 e 22 cepas de DEN-2 do Brasil. A maioria dessas cepas foi isolada no período de 1995-2001, em regiões endêmicas e de transmissão recente no Estado de São Paulo. Seqüências da junção E/NS1 de DEN-1 e DEN-2 de outras regiões geográficas brasileiras e mundiais, obtidas do GenBank, foram também utilizadas neste estudo. As análises foram efetuadas utilizando-se as técnicas de Verossimilhança Máxima e Bayesiana de inferência filogenética. Os resultados das análises das seqüências de DEN-1 e DEN-2 são ambíguos e o suporte para a maioria dos grupos é baixo, sugerindo que a região E/NS1 não é filogeneticamente informativa. O gráfico gerado na análise de decomposição dos grupos de DEN-1 não mostrou evidências de agrupamento das seqüências de acordo com os países, as regiões ou clados. No entanto, para DEN-2 evidenciou a existência de ambigüidades entre as seqüências, sugerindo que as brasileiras pertencem a subtipos distintos do genotipo III

    Imaging protoplanets: observing transition disks with non-redundant masking

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    Transition disks, protoplanetary disks with inner clearings, are promising objects in which to directly image forming planets. The high contrast imaging technique of non-redundant masking is well posed to detect planetary mass companions at several to tens of AU in nearby transition disks. We present non-redundant masking observations of the T Cha and LkCa 15 transition disks, both of which host posited sub-stellar mass companions. However, due to a loss of information intrinsic to the technique, observations of extended sources (e.g. scattered light from disks) can be misinterpreted as moving companions. We discuss tests to distinguish between these two scenarios, with applications to the T Cha and LkCa 15 observations. We argue that a static, forward-scattering disk can explain the T Cha data, while LkCa 15 is best explained by multiple orbiting companions.Comment: SPIE conference proceedin

    Caracterização das plantas daninhas em áreas de sistemas de preparo de solo de longa duração.

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    Risk factors associated with calcinosis of juvenile dermatomyositis

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    OBJETIVO: Identificar fatores de risco associados à calcinose em crianças e adolescentes com dermatomiosite juvenil. MÉTODOS: Prontuários de 54 pacientes com dermatomiosite juvenil foram estudados. Foram avaliados dados demográficos; características clínicas: grau de força muscular (I a V do Medical Research Council), presença de comprometimentos pulmonar (distúrbio ventilatório restritivo com presença ou ausência do anticorpo anti-Jo-1), gastrointestinal (refluxo gastroesofágico) e cardíaco (pericardite e/ou miocardite); exames laboratoriais: elevação de enzimas musculares (creatinoquinase, aspartato aminotransferase, alanina aminotransferase e desidrogenase lática) e terapias utilizadas: corticoterapia isolada ou associada à cloroquina e/ou imunossupressor. Os pacientes foram divididos em dois grupos de acordo com a presença ou ausência de calcinose e foram avaliados através de análise univariada e multivariada. RESULTADOS: Calcinose foi evidenciada em 23 (43%) pacientes, sendo em seis (26%) antes do diagnóstico e em 17 (74%) após. A análise univariada revelou que comprometimentos cardíaco (p = 0,01) e pulmonar (p = 0,02) e necessidade da utilização de um ou mais imunossupressores (metotrexato, ciclosporina A e/ou pulsoterapia com ciclofosfamida endovenosa) no tratamento da dermatomiosite juvenil (p = 0,03) foram associados com uma maior incidência de calcinose. A análise multivariada mostrou que comprometimento cardíaco (OR = 15,56; IC95% 1,59-152,2) e uso de um ou mais imunossupressores (OR = 4,01; IC95% 1,08-14,87) foram as únicas variáveis independentes associadas à presença de calcinose. CONCLUSÕES: O aparecimento da calcinose foi freqüente na dermatomiosite juvenil, habitualmente na evolução da doença. A calcinose foi associada aos casos mais graves, que apresentaram envolvimento cardíaco e necessitaram da utilização de imunossupressores no seu tratamento.OBJECTIVE: To identify risk factors associated with calcinosis in children and adolescents with juvenile dermatomyositis. METHODS: A review was carried out of the medical records of 54 patients with juvenile dermatomyositis. Data were collected on demographic characteristics, clinical features: muscle strength (stages I to V of the Medical Research Council scale), pulmonary involvement (restrictive pulmonary disease with presence or absence of anti-Jo1 antibodies), gastrointestinal problems (gastroesophageal reflux) and/or heart disease (pericarditis and/or myocarditis); laboratory tests: elevated muscle enzyme levels in serum (creatine phosphokinase, aspartate aminotransferase, alanine aminotransferase and/or lactate dehydrogenase); and on the treatments given: corticoid therapy in isolation or associated with hydroxychloroquine and/or immunosuppressants. The patients were divided into two groups, depending on presence or absence of calcinosis and data were evaluated by both univariate and multivariate analyses. RESULTS: Calcinosis was identified in 23 (43%) patients, and in six (26%) patients it had emerged prior to diagnosis while in 17 (74%) it was post diagnosis. The univariate analysis revealed that cardiac (p = 0.01) and pulmonary (p = 0.02) involvement and the need for one or more immunosuppressor (methotrexate, cyclosporine A and/or pulse therapy with intravenous cyclophosphamide) to treat juvenile dermatomyositis (p = 0.03) were all associated with an increased incidence of calcinosis. The multivariate analysis then demonstrated that only cardiac involvement (OR = 15.56; 95%CI 1.59-152.2) and the use of one or more immunosuppressor (OR = 4.01; 95%CI 1.08-14.87) were independently associated with the presence of calcinosis. CONCLUSIONS: Calcinosis was a frequent development among these juvenile dermatomyositis cases, generally emerging as the disease progressed. Calcinosis was associated with the more severe cases that also had cardiac involvement and where immunosuppressors had to be included in the treatment

    Potential oscillations during electro-oxidation of ethanol on platinum in alkaline media: The role of surface sites

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    The electro-oxidation of small organic molecules is one of the major areas of interest in electrocatalysis due to its potential use in energy conversion. Instabilities in alkaline solution, particularly in comparison with kinetic properties in a conventional regime, are rarely reported in the literature, despite the fact that the catalytic activity is higher in this medium and the onset potential is shifted to lower values compared to acidic media. Ethanol oxidation on polycrystalline platinum exhibits oscillations under galvanostatic control. As the reaction is structure-sensitive, it is possible to study the contribution of the three platinum basal planes to the complex kinetics. We found that Pt(100) has the major influence in the overall non-linear kinetics of ethanol electro-oxidation on Pt(poly), possibly because it has the highest formation and accumulation rate of COads. Based on the differences observed in the galvanostatic transients on Pt(poly), Pt(110) and\ Pt(100), and the absence of this behavior on Pt(111), it is possible to infer that surface sites strongly influence the kinetic scenario during the ethanol oxidation reaction.This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (2013/24162-0 and 2015/20443-0). Financial support of MINECO (CTQ13-44083-P) is greatly acknowledged

    Validation of a score tool for measurement of histological severity in juvenile dermatomyositis and association with clinical severity of disease.

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    OBJECTIVES: To study muscle biopsy tissue from patients with juvenile dermatomyositis (JDM) in order to test the reliability of a score tool designed to quantify the severity of histological abnormalities when applied to biceps humeri in addition to quadriceps femoris. Additionally, to evaluate whether elements of the tool correlate with clinical measures of disease severity. METHODS: 55 patients with JDM with muscle biopsy tissue and clinical data available were included. Biopsy samples (33 quadriceps, 22 biceps) were prepared and stained using standardised protocols. A Latin square design was used by the International Juvenile Dermatomyositis Biopsy Consensus Group to score cases using our previously published score tool. Reliability was assessed by intraclass correlation coefficient (ICC) and scorer agreement (α) by assessing variation in scorers' ratings. Scores from the most reliable tool items correlated with clinical measures of disease activity at the time of biopsy. RESULTS: Inter- and intraobserver agreement was good or high for many tool items, including overall assessment of severity using a Visual Analogue Scale. The tool functioned equally well on biceps and quadriceps samples. A modified tool using the most reliable score items showed good correlation with measures of disease activity. CONCLUSIONS: The JDM biopsy score tool has high inter- and intraobserver agreement and can be used on both biceps and quadriceps muscle tissue. Importantly, the modified tool correlates well with clinical measures of disease activity. We propose that standardised assessment of muscle biopsy tissue should be considered in diagnostic investigation and clinical trials in JDM
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