3,395 research outputs found

    Realising formal groups

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    We show that a large class of formal groups can be realised functorially by even periodic ring spectra. The main advance is in the construction of morphisms, not of objects.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol3/agt-3-8.abs.htm

    Common subbundles and intersections of divisors

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    Let V_0 and V_1 be complex vector bundles over a space X. We use the theory of divisors on formal groups to give obstructions in generalised cohomology that vanish when V_0 and V_1 can be embedded in a bundle U in such a way that V_0\cap V_1 has dimension at least k everywhere. We study various algebraic universal examples related to this question, and show that they arise from the generalised cohomology of corresponding topological universal examples. This extends and reinterprets earlier work on degeneracy classes in ordinary cohomology or intersection theory.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-42.abs.htm

    Complex cobordism of involutions

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    We give a simple and explicit presentation of the Z/2-equivariant complex cobordism ring.Comment: Published by Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol5/paper11.abs.htm

    The Self-Directed Goal Theory Experiment: A Mixed Methods Study of Personal Development Goal-Setting Programs and Self-Efficacy

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    Andragogy is not dead; it may be simply lying dormant until its essential component, self-directed learning, revives it again. The fact is that self-directed learning can be formal or informal. This mixed methods study explored the informal side of self-directed learning, concentrating on self-help (a popularized form of personal development goalsetting). Despite a thriving self-help market, several personal development goal-setting programs focus more on goal achievement, little on goal planning, and even less on the individual. A comparative analysis of autonomous, guided, and self-directed personal goal-setting programs determined if self-directedness maximizes self-efficacy. Additionally, the researcher’s original Self-Directed Goal Theory and an extensive review of previous literature further investigated what role (if any) adult education, demographics, goal characteristics, self-regulation, personal development areas, goal timing, self-monitoring, locus of control, motivation, cognition, and virtue cultivation plays in self-efficacy enhancement and overall goal success

    Second life battery energy storage systems:converter topology and redundancy selection

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    Battery energy storage systems have traditionally been manufactured using new batteries with a good reliability. The high cost of such a system has led to investigations of using second life transportation batteries to provide an alternative energy storage capability. However, the reliability and performance of these batteries is unclear and multi-modular power electronics with redundancy have been suggested as a means of helping with this issue. This paper reviews work already undertaken on battery failure rate to suggest suitable figures for use in reliability calculations. The paper then uses reliability analysis and a numerical example to investigate six different multi-modular topologies and suggests how the number of series battery strings and power electronic module redundancy should be determined for the lowest hardware cost using a numerical example. The results reveal that the cascaded dc-side modular with single inverter is the lowest cost solution for a range of battery failure rates

    Scalable iterative methods for sampling from massive Gaussian random vectors

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    Sampling from Gaussian Markov random fields (GMRFs), that is multivariate Gaussian ran- dom vectors that are parameterised by the inverse of their covariance matrix, is a fundamental problem in computational statistics. In this paper, we show how we can exploit arbitrarily accu- rate approximations to a GMRF to speed up Krylov subspace sampling methods. We also show that these methods can be used when computing the normalising constant of a large multivariate Gaussian distribution, which is needed for both any likelihood-based inference method. The method we derive is also applicable to other structured Gaussian random vectors and, in particu- lar, we show that when the precision matrix is a perturbation of a (block) circulant matrix, it is still possible to derive O(n log n) sampling schemes.Comment: 17 Pages, 4 Figure

    Identification of individual enzymes in crude extracts by acrylamide gel electrophoresis

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    Identification of enzymes by acrylamide gel electrophoresi

    Some characteristics of adaptation in am1

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    Adaptation in am

    An approach to the synthesis of biological tissue

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    Mathematical phantoms developed to synthesize realistic complex backgrounds such as those obtained when imaging biological tissue, play a key role in the quantitative assessment of image quality for medical and biomedical imaging. We present a modeling framework for the synthesis of realistic tissue samples. The technique is demonstrated using radiological breast tissue. The model employs a two-component image decomposition consisting of a slowly, spatially varying mean-background and a residual texture image. Each component is synthesized independently. The approach and results presented here constitute an important step towards developing methods for the quantitative assessment of image quality in medical and biomedical imaging, and more generally image science
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