651 research outputs found

    Population structure, phenotypic information and association studies in long-generation crops

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    Poster presented at Generation Challenge Program Annual Research Meeting. Sao Paulo (Brazil), 12-16 Sep. 200

    A Comparison between Electroluminescence Models and Experimental Results

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    Electrical insulation ages and degrades until its eventual failure under electrical stress. One cause of this relates to the movement and accumulation of charge within the insulation. The emission of a low level of light from polymeric materials while under electrical stressing occurs before the onset of currently detectable material degradation. This light is known as electroluminescence (EL) and under an ac electric field is thought to relate to the interaction of charge in close proximity to the electrode-polymer interface. Understanding the cause of this light emission gives a very high-resolution method of monitoring charge interaction and its influence on material ageing. A possible cause of this light emission is the bipolar charge recombination theory. This theory involves the injection, trapping and recombination of charge carriers during each half cycle of the applied field [1]. This work compares two models that to simulate the EL emission according to this bipolar charge recombination theory. Model 1 assumes a fixed space charge region and all injected charge is uniformly distributed in this region with charges able to either become trapped or to recombine with opposite polarity charge carriers [2]. This recombination relates directly the excitation needed for the emission of a photon of light as measured in experiments. Model 2 develops on this by accounting for the transport and extraction of charge with an exponential distribution of trap levels rather than a uniform distribution [3]. Figure 1 shows a good correlation between the two models and experimental data. The full paper will describe the models in more detail and present results comparing the simulated and experimental results under various applied waveforms. Model 1 and model 2 both provide a good correlation with experimental data but model 2 allows a greater understanding of the space charge profile in the region close to the electrodes as well as the shape of the conduction current. Further work involves developing these models to support changes in the charge trapping profiles due to material ageing and supporting simulated results with measured conduction current

    On small time asymptotics for rough differential equations driven by fractional Brownian motions

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    We survey existing results concerning the study in small times of the density of the solution of a rough differential equation driven by fractional Brownian motions. We also slightly improve existing results and discuss some possible applications to mathematical finance.Comment: This is a survey paper, submitted to proceedings in the memory of Peter Laurenc

    Curvature-dimension inequalities and Li-Yau inequalities in sub-Riemannian spaces

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    In this paper we present a survey of the joint program with Fabrice Baudoin originated with the paper \cite{BG1}, and continued with the works \cite{BG2}, \cite{BBG}, \cite{BG3} and \cite{BBGM}, joint with Baudoin, Michel Bonnefont and Isidro Munive.Comment: arXiv admin note: substantial text overlap with arXiv:1101.359

    State of the Art Review on Mobile Robots and Manipulators for Humanitarian Demining

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    Robotics solutions properly sized with suitable modularized structure and well adapted to local conditions of dangerous unstructured areas can greatly improve the safety of personnel as well as the work efficiency, productivity and flexibility. In this sense, mobile systems equipped with manipulators for detecting and locating antipersonnel landmines are considered of most importance towards autonomous/semi-autonomous mine location in a proficient, reliable, safer and effective way. This paper reviews the most relevant literature and previous research activity regarding mobile robots and manipulators for humanitarian demining.Robotics solutions properly sized with suitable modularized structure and well adapted to local conditions of dangerous unstructured areas can greatly improve the safety of personnel as well as the work efficiency, productivity and flexibility. In this sense, mobile systems equipped with manipulators for detecting and locating antipersonnel landmines are considered of most importance towards autonomous/semi-autonomous mine location in a proficient, reliable, safer and effective way. This paper reviews the most relevant literature and previous research activity regarding mobile robots and manipulators for humanitarian demining

    Manual sobre técnicas estandarizadas para la investigacion del mejoramiento del cocotero

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    El Instituto Internacional de Recursos Fitogenéticos (IPGRI), tomando en cuanta las recomendaciones aportadas por 15 países productores de cocotero, estableció una Red Internacional de Recursos Genéticos del Cocotero (COGENT) para la coordinación de actividades de importancia nacional, regional y global, particularmente en la exploración, colección, conservación y utilización del cocotero, y para establecer bases las de colaboración sobre los amplios aspectos de la investigación y desarrollo del cultivo. Una de las primeras actividades de COGENT fue trabajar para homologar las técnicas de investigación. El Manual STANTECH, como se ha llamado a este documento, permitirá a productores de cocotero e investigadores del germoplasma de este cultivo, utilizar técnicas estandarizadas a nivel mundial, como guías para el cultivo y la conservación del germoplasma. Se espera que este manual ayude a los investigadores del cocotero a obtener mejores resultados y estos puedan ser comparados, lo cual permitirá acelerar el desarrollo de variedades mejoradas para millones de agricultores dedicados a este cultivo
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