176 research outputs found

    Sensitivity analysis in a camera-LiDAR calibration model

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    Recientemente, la fusión de datos entre una cámara y un sensor de profundidad del tipo LiDAR se ha convertido en un problema de gran interés en la industria y en la ingeniería. La calidad de los modelos 3D producidos depende, en buena manera, de un proceso correcto de calibración entre ambos sensores. En este artículo, se realiza un análisis de sensibilidad en un modelo de calibración cámara-LiDAR. Se ha calculado individualmente la variabilidad de cada parámetro por el método de Sobol, basado en la técnica de ANOVA, y el método FAST, que se basa en el análisis de Fourier. Se han definido los parámetros más sensibles y con mayor tendencia a introducir errores en nuestra plataforma de reconstrucción. Se han simulado múltiples conjuntos de parámetros para su análisis y comparación utilizando los métodos de Monte Carlo e Hipercubo Latino. Se muestran estadísticas sobre la sensibilidad total y global de cada parámetro. Además, se presentan resultados sobre la relación de sensibilidad en la calibración cámara-LiDAR, el costo computacional, el tiempo de simulación, la discrepancia y la homogeneidad en los datos simulados.Recently the data fusion between a camera and a depth sensor of LiDAR type, has become an issue of major concern in industry and engineering. The quality of the delivered 3D models depends greatly on a proper calibration between sensors. This paper presents a sensitivity analysis in a camera-lidar calibration model. The variability of each parameter was calculated individually by the Sobol method, based on ANOVA technique, and the FAST method, which is based on Fourier analysis. Multiple sets of parameters were simulated using Monte Carlo and Latin Hypercube methods for the purpose of comparing the results of the sensitivity analysis. We defined which parameters are the most sensitive and prone to introduce error into our reconstruction platform. Statistics for the total and global sensibility analysis for each sensor and for each parameter are presented. Furthermore, results on the sensitivity ratio on camera-LiDAR calibration, computational cost, time simulation, discrepancy and homogeneity in the simulated data are presented.Peer Reviewe

    Conservation biogeography of ecologically interacting species: The case of the Iberian lynx and the European rabbit

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    Aim To relate the recent Iberian lynx decline to changes in the distribution of the European rabbit after the haemorrhagic disease outbreak of 1989. As Iberian rabbits evolved in two geographically separated lineages, being the recent lynx range practically restricted to the southwestern lineage, we also test if differential range dynamics exists for these lineages, with the consequent implications for lynx conservation and reintroduction planning

    Nutritional Evaluation Of Children With Chronic Cholestatic Disease

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)To evaluate the nutritional status of children with persistent cholestasis and to compare the anthropometric indices between children with and without liver cirrhosis and children with and without jaundice. Methods Children with persistent cholestasis, i.e. increased direct bilirrubin or changes in the canalicular enzyme gamma-glutamyl transferase (GGT), were included. The anthropometric measures were weight (W), height or length (H), arm circumference (AC), triceps skinfold thickness (TST), arm muscle circumference (AMC), and body mass index (BMI). Results Ninety-one children with cholestasis, with current median age of 12 months, were evaluated. W/age (A) and H/A indices below -2 Z-scores were observed in 33% and 30.8% of patients, respectively. Concerning the W/H index and BMI, only 12% and 16% of patients, respectively, were below -2 Z-scores. Regarding AC, 43.8% of 89 evaluated patients had some depletion. Observing the TST, 64% of patients had depletion, and 71.1% of the 45 evaluated patients had some degree of depletion regarding the ACM index. Conclusion Evaluation using weight in patients with chronic liver diseases may overestimate the nutritional status due to visceromegaly, subclinical edema, or ascites. Indices that correlate weight and height, such as W/H and BMI, may also not show depletion because of the chronic condition in which there are depletion of both weight and height. TST, AC, and ACM are parameters that better estimate nutritional status and should be part of the management of patients with liver diseases and cholestasis. © 2015 Sociedade Brasileira de Pediatria.922197205CNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Assessment of risk factors for HIV infection among men who have sex with men in the metropolitan area of Campinas City, Brazil, using respondent-driven sampling

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    The Population Council, in collaboration with the Brazil Ministry of Health, the Municipal Program of STD/AIDS of Campinas, and the US Centers for Disease Control and Prevention/Global AIDS Program/Brazil, conducted a study to characterize the sociodemographic, behavioral, and environmental factors associated with subgroups of MSM who are most at risk for HIV infection. This research is the first Brazilian study to provide population-based estimates for HIV, syphilis, and HIV-related risk behaviors using an innovative sampling technique to reach members of the target population. Our data suggest the importance for HIV prevention programs to address not only sexual risk reduction, but also other social and cultural factors such as their vulnerability to homophobic violence, social construction of sexual identity, and social norms regarding sexuality and condom use within their social networks. The findings from this study clearly indicate the importance of the population of MSM in the HIV epidemic and the need for targeted interventions, particularly for the risky sub-populations in Campinas

    Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System

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    We present a series of measurements based on K -> pi+pi- and K -> pi0pi0 decays collected in 1996-1997 by the KTeV experiment (E832) at Fermilab. We compare these four K -> pipi decay rates to measure the direct CP violation parameter Re(e'/e) = (20.7 +- 2.8) x 10^-4. We also test CPT symmetry by measuring the relative phase between the CP violating and CP conserving decay amplitudes for K->pi+pi- (phi+-) and for K -> pi0pi0 (phi00). We find the difference between the relative phases to be Delta-phi = phi00 - phi+- = (+0.39 +- 0.50) degrees and the deviation of phi+- from the superweak phase to be phi+- - phi_SW =(+0.61 +- 1.19) degrees; both results are consistent with CPT symmetry. In addition, we present new measurements of the KL-KS mass difference and KS lifetime: Delta-m = (5261 +- 15) x 10^6 hbar/s and tauS = (89.65 +- 0.07) x 10^-12 s.Comment: Submitted to Phys. Rev. D, August 6, 2002; 37 pages, 32 figure

    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

    Polyphasic analysis of Acidovorax citrulli strains from northeastern Brazil

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    ABSTRACT Bacterial fruit blotch (BFB) of cucurbit plants is caused by Acidovorax citrulli and represents a serious concern to melon (Cucumis melo L.) growers worldwide, including those in Brazil. Thirty-four A. citrulli strains from different melon production areas of northeastern Brazil were characterized for their virulence on melon fruits and their substrate utilization and molecular profiles. Based on the analysis of BFB severity on melon fruits, the A. citrulli strains were divided into three groups, classified as mildly, moderately or highly virulent. Although host-related groups were not observed, the watermelon and ‘melão-pepino’ strains exhibited only low or moderate virulence on melon fruit. Substrate utilization profiles revealed that 94 % of the 95 tested compounds were used by A. citrulli strains as a carbon source. Overall, based on substrate utilization, low variability was observed with no relationship to host of origin. The formation of one group of A. citrulli strains based on Repetitive Sequence-based PCR (rep-PCR) analysis confirmed the low variability observed in the substrate utilization analyses. Bayesian inference based on the analysis of 23S rDNA partial sequence data resulted in one well-supported clade and clustered the strains with the A. citrulli-type species with high posterior probability support. Based on the markers used, the Brazilian A. citrulli strains belong to a single group, which corresponds to the previously described Group I for this bacterium in the United States
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