76 research outputs found

    Efficient Training Set Use For Blood Pressure Prediction in a Large Scale Learning Classifier System

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    ABSTRACT We define a machine learning problem to forecast arterial blood pressure. Our goal is to solve this problem with a large scale learning classifier system. Because learning classifiers systems are extremely computationally intensive and this problem's eventually large training set will be very costly to execute, we address how to use less of the training set while not negatively impacting learning accuracy. Our approach is to allow competition among solutions which have not been evaluated on the entire training set. The best of these solutions are then evaluated on more of the training set while their offspring start off being evaluated on less of the training set. To keep selection fair, we divide competing solutions according to how many training examples they have been tested on

    Nanometer-scale ablation with a table-top soft x-ray laser

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    Includes bibliographical references (page 3617).Ablation of holes with diameters as small as 82 nm and very clean walls was obtained in poly(methyl methacrylate) focusing pulses from a Ne-like Ar 46.9 nm compact capillary-discharge laser with a freestanding Fresnel zone plate diffracting into third order. These results demonstrate the feasibility of using focused soft x-ray laser beams for the direct nanoscale patterning of materials and the development of new nanoprobes

    Computational Stem Cell Biology: Open Questions and Guiding Principles

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    Computational biology is enabling an explosive growth in our understanding of stem cells and our ability to use them for disease modeling, regenerative medicine, and drug discovery. We discuss four topics that exemplify applications of computation to stem cell biology: cell typing, lineage tracing, trajectory inference, and regulatory networks. We use these examples to articulate principles that have guided computational biology broadly and call for renewed attention to these principles as computation becomes increasingly important in stem cell biology. We also discuss important challenges for this field with the hope that it will inspire more to join this exciting area

    A Dominated Coupling From The Past algorithm for the stochastic simulation of networks of biochemical reactions

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    <p>Abstract</p> <p>Background</p> <p>In recent years, stochastic descriptions of biochemical reactions based on the Master Equation (ME) have become widespread. These are especially relevant for models involving gene regulation. Gillespie’s Stochastic Simulation Algorithm (SSA) is the most widely used method for the numerical evaluation of these models. The SSA produces exact samples from the distribution of the ME for finite times. However, if the stationary distribution is of interest, the SSA provides no information about convergence or how long the algorithm needs to be run to sample from the stationary distribution with given accuracy. </p> <p>Results</p> <p>We present a proof and numerical characterization of a Perfect Sampling algorithm for the ME of networks of biochemical reactions prevalent in gene regulation and enzymatic catalysis. Our algorithm combines the SSA with Dominated Coupling From The Past (DCFTP) techniques to provide guaranteed sampling from the stationary distribution. The resulting DCFTP-SSA is applicable to networks of reactions with uni-molecular stoichiometries and sub-linear, (anti-) monotone propensity functions. We showcase its applicability studying steady-state properties of stochastic regulatory networks of relevance in synthetic and systems biology.</p> <p>Conclusion</p> <p>The DCFTP-SSA provides an extension to Gillespie’s SSA with guaranteed sampling from the stationary solution of the ME for a broad class of stochastic biochemical networks.</p

    Efeitos de retardadores de crescimento na frutificação da videira 'Niagara Rosada'

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    Studies were carried out to establish the effects of exogenous growth regulators on Vitis (labrusca x vinifera) 'Niagara Rosada' fruiting. The investigations were done in the Jundiaí Research Station, Agronomic Institute State of São Paulo, always using disease-free vineyards of good productivity. The morphological transformations of clusters were studied under the following aspects: weight, length and width of cluster; weight, length average and width average of berries: length average/width average ratio of berries; length and diameter of rachis; width of cluster minus berries; length and diameter of secondary rachis. The yield for the first half of the period from flowering to maturation was first determined. The same characteristics were determined at the time of maturity plus the number of berries, number of seeds, total sugars, total acid, Maturity Index and reducing sugars in samples of all treatments. The experiment was conducted in order to determine the doses that resulted in the most beneficial effects, always using applications by immersion of the inflorescence. In the experiment was realized applications of (2-chloroethyl) trimethylammonium chloride (CCC) and succinic aeid-2, 2-dimethylhydrazide (SADH) at concentrations of 50, 100, 250, 500, 1000 and 2000 ppm; CCC 500 ppm plus SADH 500 ppm and nontreated, 5 days before flowering, in 1971. The concentrations of CCC applied before flowering did not affect favorably cluster morphology under the conditions of the experiment. Application of SADH at 250 ppm before flowering increased the cluster weight and length, berries number and weight, and seed number. In the first yield treatment of 1000 ppm of SADH increased the cluster weight and lenght, berry weight and rachis lenght.Estudou-se a influência da aplicação por imersão, de retardadores de crescimento (CCC e SADH), 5 dias antes do florescimento, nas características morfológicas da panícuia da videira Vitis (labrusca x vinifera) 'Niagara Rosada'. Neste ensaio verificou-se que as concentrações de CCC aplicadas em pré-florescimento, não afetaram favoravelmente a morfologia das panículas da cultivar estudada, nas condições do ensaio. SADH na dosagem de 1000 ppm provocou, na primeira colheita, aumento no peso e comprimento da panícula, no peso das bagas, e no comprimento da ráquis, proporcionando a formação desejada de uma panícula mais alongada, nas condições estudadas. Aplicação de SADH na concentração de 250 ppm em pré-florescimento, promoveu aumento no peso e comprimento da panícula, número e peso das bagas, além do inconveniente de elevar o número de sementes

    M.: Interactive operators for evolutionary architectural design

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    ABSTRACT In this paper we explore different techniques that allow the user to direct interactive evolutionary search. Broadening interaction beyond simple evaluation increases the amount of feedback and bias a user can apply to the search. Increased feedback will have the effect of directing the algorithm to more fruitful areas of the search space. This paper examines whether additional feedback from the user can be a benefit to the problem of evolutionary design. We find that the interface between the user and the search space plays a vital role in this process

    Improved liquid jet laser-plasma source for X-ray microscopy

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    We increase the x-ray flux from a liquid-jet laser-plasma x-ray source by optimizing the target geometry. A new nozzle fabrication method allows us to produce stable microscopic liquid jets with a wide range of diameters. The improved x-ray flux is demonstrated by optimizing the diameter of an ethanol liquid-jet for our 3 ns, â–¡=532\square=532 nm Nd: YAG laser and measuring the flux at the â–¡=3.37\square=3.37 nm C VI emission line. Preliminary data suggest that the x-ray flux can be increased by more than a factor of 4 compared to previous experiments. The goal is to significantly reduce the exposure time of our laser-plasma-based compact x-ray microscope by improving the source

    Liquid-jet laser-plasma X-ray sources for microscopy and lithography

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    We review the development of compact laser-plasma soft x-ray sources based on microscopic liquid-drop or liquid-jet targets. It is shown that such sources provide practically debris-free, high-flux operation at water-window and EUV wavelengths. This regenerative and solid-density target system holds promise for the generation of high-average power using high-repetition-rate lasers. Application of the source to compact x-ray microscopy, multilayer-optics characterization and EUV lithography is briefly discussed

    Western Star, 1911-04-05

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    The Western Star began publication on Newfoundland's west coast on 4 April 1900, appearing weekly with brief semiweekly periods up to 1952, when it became a daily. As of 17 April 2019 it continues as a free weekly community paper
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