717 research outputs found

    The Roosevelt – Rondon expedition marmoset (Mico marcai) : unveiling the conservation status of a data deficient species

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    The Roosevelt-Rondon Expedition marmoset, Mico marcai, was collected in 1914 and to date, all information on this species comes from three skins brought back by the Expedition and two additional skins collected in the 1990s. It is no surprise then that M.marcai has been classified as Data Deficient (DD). Given that Mico marcai’s suspected range sits on the path of the advancing Brazilian “Arc-of-Deforestation”, it is urgent that relevant data be collected to assess this taxon. Here we present the first comprehensive field data on the distribution, population size and threats on M. marcai with the goal of removing the species from the DD category. From 2012 to 2015, we surveyed for the species in 11 localities, in and around the Marmelos-Aripuanã interfluve, and estimated density using distance sampling on 10 transects. We also used spatial predictive modelling to project the amount of habitat that will be lost within its range in 18 years under different deforestation scenarios. We found marmosets in 14 localities and calculated its Extent of Occurrence to be 31,073 km2. We walked 271 km and detected 30 marmoset groups, allowing us to estimate their density to be 8.31 individuals/km2 and a total population of 258,217.71 individuals. By a “Business as usual” scenario, 20,181 km2 of habitat will be lost in three marmoset generations (~18 years), compromising 33% of the species’ range. Accordingly, M. marcai should be classified as globally Vulnerable under category A3c. Following our study, we propose the Amazonian marmosets, genus Mico, should undergo similar re-assessment as their ranges all fall in the path of the Arc-of-Deforestation. Keywords: Amazonian marmosets, Conservation Status, Data Deficient, Habitat Loss, Southern Amazoni

    TEORIAS DE ENFERMAGEM: IMPORTÂNCIA DA CORRETA APLICAÇÃO DOS CONCEITOS

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    Theoretical-reflexive research, whose aim is to analyze the clarity of concept stimulus in the Roy Model, for best comprehension in nursing practice. It was developed in three phases: 1- Search of studies that utilized the Roy Model; 2- Conducted reading for comprehension of the concept stimulus and 3- Analysis of clarity of the concept. The three studies were conducted at master level. The analysis of the studies shows deficiency in the clarity of the concept stimulus, being predominant the ambiguity in the classification and differentiation of the focal and contextual stimuli, without the existence of consistency and uniformity. The need arises to deepen the theories of nursing for adequate application in the areas of research: nursing education and practice, optimizing and improving its use, as well as, enabling the comprehension of determined concepts that are not sufficiently clear. The worries that arise among the nurses will provide a more profound approach to the study, enabling the advance of theories, as well as new findings, leading to necessary changes.  Investigación teórico-reflexiva cuyo objetivo fue analizar la claridad del concepto estímulo según el  modelo de Roy, para mayor comprensión en la práctica de enfermería. Desarrollada en tres etapas: 1ª- Levantamiento de estudios que utilizaron el Modelo de Roy; 2ª - Lectura dirigida hacia la comprensión del concepto estímulo y 3ª - Análisis de la claridad del concepto. Fueron utilizados tres estudios, a  nivel de maestrado. El análisis de los estudios demuestra deficiencia en la claridad del concepto estímulo, predominando ambigüedad en la clasificación y diferenciación de los estímulos focales y contextuales, sin consistencia y uniformidad. Se evidencia la necesidad de profundizar en las teorías de enfermería, para su aplicación adecuada en las áreas de investigación, enseñanza y práctica, optimizando y mejorando su uso, además de posibilitar la comprensión de determinados conceptos no suficientemente claros. Las inquietudes surgidas entre los enfermeros podrán motivar un abordaje más profundo de los estudios, posibilitando el avance de las teorías, así  como nuevos descubrimientos, dirigiendo los cambios necesariosPesquisa teórico-reflexiva, objetivando analisar a clareza do conceito estímulo no modelo de Roy, para maior compreensão na prática de enfermagem. Desenvolvido em três etapas: 1ª- Levantamento de estudos que utilizaram o Modelo de Roy; 2ª - Leitura dirigida para a compreensão do conceito estímulo e 3ª - Análise da clareza do conceito. Foram utilizados três estudos, em nível de mestrado. A análise dos estudos demonstra deficiência na clareza do conceito estímulo, predominando ambigüidade na classificação e diferenciação dos estímulos focais e contextuais, não existindo consistência e uniformidade. Evidencia-se a necessidade do aprofundamento nas teorias de enfermagem, para a aplicação adequada nas áreas de pesquisa, ensino e prática, otimizando e aprimorando seu uso, além de possibilitar a compreensão de determinados conceitos, não suficientemente claros. As inquietações surgidas entre os enfermeiros poderão proporcionar o aprofundamento nos estudos, possibilitando o avanço das teorias, assim como novos achados, direcionando as mudanças necessárias

    Exact exchange-correlation potential of a ionic Hubbard model with a free surface

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    We use Lanczos exact diagonalization to compute the exact exchange-correlation (xc) potential of a Hubbard chain with large binding energy ("the bulk") followed by a chain with zero binding energy ("the vacuum"). Several results of density functional theory in the continuum (sometimes controversial) are verified in the lattice. In particular we show explicitly that the fundamental gap is given by the gap in the Kohn-Sham spectrum plus a contribution due to the jump of the xc-potential when a particle is added. The presence of a staggered potential and a nearest-neighbor interaction V allows to simulate a ionic solid. We show that in the ionic regime in the small hopping amplitude limit the xc-contribution to the gap equals V, while in the Mott regime it is determined by the Hubbard U interaction. In addition we show that correlations generates a new potential barrier at the surface

    Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

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    We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged. © 2013 Lombardo et al

    Avaliação Subjetiva da Condição do Pavimento Flexível de Subtrechos de uma via da Cidade de Barreiras-Ba

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    The study of the surface quality of the pavement is of fundamental importance, since it allows determining the state in which it is located and allows better use of the available resources. In addition to allowing the recognition of sections of the road that require improvements and that must be prioritized. This research aims to subjectively analyze the surface condition of flexible pavement using the current service value (VSA) method, with the help of a visual scale built based on the proposal of Oliveira et al. (2013). The VSA analysis on Rua Capitão Manoel Miranda, located in the center of Barreiras, was carried out considering two different times of the day, with the aim of observing how different temperature and humidity conditions interfere with the comfort and smoothness of the trip offered to the users. The road was divided into four subsections of 600 meters each, totaling 2.4 kilometers. The surface of the road under study was classified as “good” after analyzing photographs using the visual scale and “fair” through the VSA evaluation. Once the final VSA (2.54) determined for the track was close to the accepted limit, it indicates the need to perform corrective maintenance and, subsequently, periodic preventive maintenance.El estudio de la calidad superficial del pavimento es de fundamental importancia, ya que permite determinar el estado en el que se encuentra el mismo y permite un mejor aprovechamiento de los recursos disponibles. Además de permitir el reconocimiento de tramos de la vía que requieren mejoras y que se deben priorizar. Esta investigación tiene como objetivo analizar subjetivamente el estado superficial del pavimento flexible utilizando el método del valor de servicio actual (VSA), con la ayuda de una escala visual construida con base en la propuesta de Oliveira et al. (2013). El análisis VSA en la Rua Capitão Manoel Miranda, ubicada en el centro de Barreiras, se realizó considerando dos momentos diferentes del día, con el objetivo de observar cómo las diferentes condiciones de temperatura y humedad interfieren en el confort y la suavidad del viaje ofrecido a los usuarios. La vía se dividió en cuatro subtramos de 600 metros cada uno, totalizando 2,4 kilómetros. La superficie de la vía en estudio fue clasificada como “buena” tras el análisis de fotografías mediante la escala visual y “regular” mediante la evaluación de VSA. Una vez que el VSA final (2.54) determinado para la vía estuvo cerca del límite de aceptado, indica la necesidad de realizar un mantenimiento correctivo y, posteriormente, un mantenimiento preventivo periódico.Estudar a qualidade superficial do pavimento é de fundamental importância, tendo em vista que possibilita a constatação da condição em que se encontra e proporciona um melhor aproveitamento dos recursos disponíveis. Além de permitir o reconhecimento de seções que necessitam de melhorias e que devem ser priorizadas. Esta pesquisa tem por objetivo analisar subjetivamente a condição superficial do pavimento flexível através do método de valor de serventia atual (VSA), com auxílio de escala visual montada com base na proposta por Oliveira et. al (2013). A análise por VSA na Rua Capitão Manoel Miranda, localizada no centro de Barreiras foi realizada considerando dois horários distintos do dia, com o intuito de observar como condições diferentes de temperatura e umidade, interferem no conforto e suavidade de rolamento oferecida aos usuários. A via foi dividida em quatro subtrechos de 600 metros cada um, totalizando 2,4 km de via. A superfície de rolamento da via em estudo foi classificada como “boa” após análise de fotografias por escala visual e “regular” através da avaliação por VSA. Uma vez que o VSA final (2,54) determinado para a via ficou próximo do limite de aceitabilidade, verificou-se a necessidade de realizar manutenção do tipo corretiva e, posteriormente manutenções preventivas periódicas

    Dissecting the Relation between a Nuclear Receptor and GATA: Binding Affinity Studies of Thyroid Hormone Receptor and GATA2 on TSHβ Promoter

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    Background: Much is known about how genes regulated by nuclear receptors (NRs) are switched on in the presence of a ligand. However, the molecular mechanism for gene down-regulation by liganded NRs remains a conundrum. The interaction between two zinc-finger transcription factors, Nuclear Receptor and GATA, was described almost a decade ago as a strategy adopted by the cell to up-or down-regulate gene expression. More recently, cell-based assays have shown that the Zn-finger region of GATA2 (GATA2-Zf) has an important role in down-regulation of the thyrotropin gene (TSH beta) by liganded thyroid hormone receptor (TR). Methodology/Principal Findings: In an effort to better understand the mechanism that drives TSH beta down-regulation by a liganded TR and GATA2, we have carried out equilibrium binding assays using fluorescence anisotropy to study the interaction of recombinant TR and GATA2-Zf with regulatory elements present in the TSH beta promoter. Surprisingly, we observed that ligand (T3) weakens TR binding to a negative regulatory element (NRE) present in the TSH beta promoter. We also show that TR may interact with GATA2-Zf in the absence of ligand, but T3 is crucial for increasing the affinity of this complex for different GATA response elements (GATA-REs). Importantly, these results indicate that TR complex formation enhances DNA binding of the TR-GATA2 in a ligand-dependent manner. Conclusions: Our findings extend previous results obtained in vivo, further improving our understanding of how liganded nuclear receptors down-regulate gene transcription, with the cooperative binding of transcription factors to DNA forming the core of this process.Medical Research Council (MRC), UKConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazi

    Stroke Correlates in Chagasic and Non-Chagasic Cardiomyopathies

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    BACKGROUND: Aging and migration have brought changes to the epidemiology and stroke has been shown to be independently associated with Chagas disease. We studied stroke correlates in cardiomyopathy patients with focus on the chagasic etiology. METHODOLOGY/PRINCIPAL FINDINGS: We performed a cross-sectional review of medical records of 790 patients with a cardiomyopathy. Patients with chagasic (329) and non-chagasic (461) cardiomyopathies were compared. There were 108 stroke cases, significantly more frequent in the Chagas group (17.3% versus 11.1%; p<0.01). Chagasic etiology (odds ratio [OR], 1.79), pacemaker (OR, 2.49), atrial fibrillation (OR, 3.03) and coronary artery disease (OR, 1.92) were stroke predictors in a multivariable analysis of the entire cohort. In a second step, the population was split into those with or without a Chagas-related cardiomyopathy. Univariable post-stratification stroke predictors in the Chagas cohort were pacemaker (OR, 2.73), and coronary artery disease (CAD) (OR, 2.58); while atrial fibrillation (OR, 2.98), age over 55 (OR, 2.92), hypertension (OR, 2.62) and coronary artery disease (OR, 1.94) did so in the non-Chagas cohort. Chagasic stroke patients presented a very high frequency of individuals without any vascular risk factors (40.4%; OR, 4.8). In a post-stratification logistic regression model, stroke remained associated with pacemaker (OR, 2.72) and coronary artery disease (OR, 2.60) in 322 chagasic patients, and with age over 55 (OR, 2.38), atrial fibrillation (OR 3.25) and hypertension (OR 2.12; p = 0.052) in 444 non-chagasic patients. CONCLUSIONS/SIGNIFICANCE: Chagas cardiomyopathy presented both a higher frequency of stroke and an independent association with it. There was a high frequency of strokes without any vascular risk factors in the Chagas as opposed to the non-Chagas cohort. Pacemaker rhythm and CAD were independently associated with stroke in the Chagas group while age over 55 years, hypertension and atrial fibrillation did so in the non-Chagas cardiomyopathies

    Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use

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    Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù

    Chromosome characterization and variability in some Iridaceae from Northeastern Brazil

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    The chromosomes of 15 species of Iridaceae of the genera Alophia, Cipura, Eleutherine, Neomarica and Trimezia (subfamily Iridoideae) were examined after conventional Giemsa staining. The karyotypes of Alophia drummondii (2n = 14+1B, 28, 42 and 56), Cipura paludosa (2n = 14), C. xanthomelas (2n = 28) and Eleutherine bulbosa (2n = 12) were asymmetric; Neomarica candida, N. caerulea, N. humilis, N. glauca, N. gracilis, N. northiana and Neomarica sp. (2n = 18); N. cf. paradoxa (2n = 28), Trimezia fosteriana (2n = 52), T. martinicensis (2n = 54) and T. connata (2n = 82) were all generally symmetric. New diploid numbers of 2n = 56 for Alophia drummondii, 2n = 18 for N. candida, N. humilis, N. glauca, and N. gracilis, 2n = 28 for N. cf. paradoxa, and 2n = 82 for T. connata are reported. The karyotypic evolution of the studied species is discussed
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