872 research outputs found

    Polarimetric SAR Image Segmentation with B-Splines and a New Statistical Model

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    We present an approach for polarimetric Synthetic Aperture Radar (SAR) image region boundary detection based on the use of B-Spline active contours and a new model for polarimetric SAR data: the GHP distribution. In order to detect the boundary of a region, initial B-Spline curves are specified, either automatically or manually, and the proposed algorithm uses a deformable contours technique to find the boundary. In doing this, the parameters of the polarimetric GHP model for the data are estimated, in order to find the transition points between the region being segmented and the surrounding area. This is a local algorithm since it works only on the region to be segmented. Results of its performance are presented

    Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

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    The Gram-negative bacterium Xanthomonas axonopodis pv. citri, the causal agent of citrus canker, is a major threat to the citrus industry worldwide. Although this is a leaf spot pathogen, it bears genes highly related to degradation of plant cell walls, which are typically found in plant pathogens that cause symptoms of tissue maceration. Little is known on Xac capacity to cause disease and hydrolyze cellulose. We investigated the contribution of various open reading frames on degradation of a cellulose compound by means of a global mutational assay to selectively screen for a defect in carboxymethyl cellulase (CMCase) secretion in X. axonopodis pv. citri. Screening on CMC agar revealed one mutant clone defective in extracellular glycanase activity, out of nearly 3,000 clones. The insertion was located in the xpsD gene, a component of the type II secretion system (T2SS) showing an influence in the ability of Xac to colonize tissues and hydrolyze cellulose. In summary, these data show for the first time, that X. axonopodis pv. citri is capable of hydrolyzing cellulose in a T2SS-dependent process. Furthermore, it was demonstrated that the ability to degrade cellulose contributes to the infection process as a whole

    Evidence of contamination by oil and oil products in the Santos-Sao Vicente estuary, Sao Paulo, Brazil

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    Different components of the mixed function oxidase (MFO) system and the levels of fluorescent aromatic compounds in bile (FACs) were measured in Cathorops spixii in order to assess the impact of polycyclic aromatic hydrocarbons (PAHs). Fish were sampled in an estuary (Santos/Sao Vicente) with a history of contamination by PAHs, mainly due to the presence of the industrial complex of Cubatao city and of another of low anthropogenic influence (Cananeia) on the Brazilian coast. FACs were higher in fish from the polluted site, and the PAH 5 and 6-ring metabolites were the most frequent - with 14% and 15%, respectively. Levels of the different components of the MFO system showed the same variation profile as the FACs for both estuaries. Therefore, the values found for somatic indexes and biomarkers with data of bile PAH metabolites indicate the presence of organic contaminants, especially in the area subject to the influence of the industrial complex on the Santos/Sao Vicente estuary.CAPES (Brazilian Agency for Science and Technology); Oceanographic Institute of Sao Paulo University; Laboratory of Ecotoxicology and Environmental Chemistry of the University of Algarve; CAPES-PDEE [BEX 2176/07-6]info:eu-repo/semantics/publishedVersio

    Pharmacological activity of the hydroalcoholic extract from Hovenia dulcis thunberg fruit and the flavonoid dihydromyricetin during hypercholesterolemia induced in rats

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    Cerebrovascular accidents and coronary artery disease are the leading causes of cardiovascular mortalities in Brazil and high levels of LDL cholesterol are one of the main risk factors. In this context, several plant extracts and natural substances have shown promise as cholesterol-lowering. The objective of this study was to evaluate the potential of the hydroalcoholic extract of the fruit of H. dulcisand of dihydromyricetin in cholesterol reduction in hypercholesterolemic rats. Forty-two Wistar male rats were distributed into seven groups of six animals that received diets supplemented with 1% cholesterol and 0.3% cholic acid, with the exception of the control group, which received conventional diets. Animals were treated with oral suspensions containing: atorvastatin 1.0 mg/kg; H. dulcisextract at 50.0 and 100.0 mg/kg and dihydromyricetin at 25.0 and 50.0 mg/kg vehicle (control group). The following biochemical markers were evaluated; total cholesterol, HDL-C, LDL-C, triglycerides, AST, ALT, and alkaline phosphatase. The hypercholesterolemic diet was effective in inducing hypercholesterolemia, increasing total cholesterol by 112.7% relative to the control group. The treatments with two doses of the extract proved to be promising hypocholesterolemic agents, as they were able to substantially reduce total cholesterol and LDL-C, without significantly altering triglycerides, hepatic transaminases, and alkaline phosphatase, thereby encouraging the studies with the plant H. dulcis. The groups treated with the flavonoid dihydromyricetin, although they showed a significant reduction in total cholesterol and LDL-C, and found increases in triglycerides and hepatic transaminases, which is unwanted in the context of hypercholesterolaemia

    Motor development of children with attention deficit hyperactivity disorder

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    Objective: To compare both global and specific domains of motor development of children with attention deficit hyperactivity disorder (ADHD) with that of typically developing children. Methods: Two hundred children (50 children with clinical diagnoses of ADHD, according to the DSM-IV-TR and 150 typically developing controls), aged 5 to 10 years, participated in this crosssectional study. The Motor Development Scale was used to assess fine and global motricity, balance, body schema, and spatial and temporal organization. Results: Between-group testing revealed statistically significant differences between the ADHD and control groups for all domains. The results also revealed a deficit of nearly two years in the motor development of children with ADHD compared with the normative sample. Conclusion: The current study shows that ADHD is associated with a delay in motor development when compared to typically developing children. The results also suggested difficulties in certain motor areas for those with ADHD. These results may point to plausible mechanisms underlying the relationship between ADHD and motor difficulties

    Avaliação da incidência de antracnose, do desempenho e estado nutricional de variedades de mangueira, para cultivo orgânico, na região centro-norte do Estado de São Paulo.

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    A mudança do perfil do consumidor, aliada aos riscos da contaminação por agrotóxicos, tem levado à busca de alternativas ecologicamente apropriadas para produção de frutas. Os objetivos deste trabalho foram avaliar a incidência de antracnose, o desempenho e estado nutricional de variedades de mangueira conduzidas organicamente na região de Pindorama-SP. Foram utilizadas 17 variedades de mangueira. O experimento foi instalado em delineamento experimental em blocos completos ao acaso, com 17 tratamentos (variedades) e seis repetições. Foi avaliada a severidade de antracnose nas folhas, através de uma escala diagramática, atribuindo-se notas aos sintomas. Foram avaliados o crescimento e o desenvolvimento (altura da planta, perímetro do tronco e da copa) e o estado nutricional, mediante análise foliar, das diferentes variedades utilizadas. Através dos resultados obtidos, podem-se considerar como muito suscetíveis à antracnose as variedades Bourbon, Rocha e Rosa; e resistentes, as variedades IAC 111, Alfa, Beta e Parvin; as variedades de manga apresentaram o mesmo padrão de crescimento; as maiores alturas da planta corresponderam aos maiores diâmetros do tronco e da copa; a variedade Parvin apresentou o melhor desempenho dentre as variedades estudadas, com relação à resistência à antracnose, altura e diâmetro do caule e da copa, podendo ser recomendada ao cultivo orgânico. As variedades Omega e Alfa também apresentaram bom crescimento, podendo ser indicadas para esse cultivo, pelo menos nessa fase inicial; as variedades Surpresa e Rosa não apresentaram bom desempenho, no campo, em relação às demais, não devendo ser recomendadas para o cultivo orgânico, principalmente a variedade Rosa, bastante suscetível à antracnose. As concentrações de N, P e K foram elevadas na fase vegetativa das plantas, comparadas à baixa concentração de Ca; houve carência de Boro em todas as variedades estudadas. A manga Rosa, provavelmente, sofreu toxicidade ao excesso de manganês, ocasionando diminuição em seu desenvolvimento
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