752 research outputs found

    On-Line Balancing of Random Inputs

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    We consider an online vector balancing game where vectors vt, chosen uniformly at random in {−1,+1}n, arrive over time and a sign xt∈{−1,+1} must be picked immediately upon the arrival of vt. The goal is to minimize the L∞ norm of the signed sum ∑txtvt. We give an online strategy for picking the signs xt that has value O(n1/2) with high probability. Up to constants, this is the best possible even when the vectors are given in advance

    Fragmentation of bacteriophage S13 replicative from DNA by restriction endonucleases from Hemophilus influenzae and Hemophilus aegyptius.

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    The restriction enzymes Hind from Hemophilus influenzae and HaeIII from Hemophilus aegyptius cleave bacteriophage S13 replicative form (RF) DNA into 13 and 10 specific fragments, respectively. The sizes of these fragments were estimated by gel electrophoresis, electron microscopy, and pyrimidine isostich analysis. The Hind and HaeIII fragments were ordered relative to each other by cross digestion and a physical map of the S13 genome constructed. Comparison of the Hind cleavage patterns of S13 RF DNA and X174 RF DNA showed the majority of the fragments from the two DNAs coincided with each other except for three of the thirteen S13 fragments and three of the thirteen X174 fragments. Comparison of the HaeIII patterns of the two DNAs revealed a lack of coincidence of one S13 fragment only and two X174 fragments. From the data obtained by the cleavage of the two DNAs by Hind and HaeIII, a correlation between the physical restriction enzyme cleavage maps and the genetic map of the two phages was made. The differences in cleavage of the two DNAs by the restriction enzymes have been explained by changes in two restriction enzyme sites in the AB region and one change of site in the F region of the genetic map of the two bacteriophages

    On-line balancing of random inputs

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    We consider an online vector balancing game where vectors vt, chosen uniformly at random in {− 1, + 1}n, arrive over time and a sign xt ∈ {− 1, + 1} must be picked immediately upon the arrival of vt. The goal is to minimize the L∞ norm of the signed sum (Formula presented.).

    Football in the community schemes: Exploring the effectiveness of an intervention in promoting healthful behaviour change

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    This study aims to examine the effectiveness of a Premier League football club’s Football in the Community (FitC) schemes intervention in promoting positive healthful behaviour change in children. Specifically, exploring the effectiveness of this intervention from the perspectives of the participants involved (i.e. the researcher, teachers, children and coaches). A range of data collection techniques were utilized including the principles of ethnography (i.e. immersion, engagement and observations), alongside conducting focus groups with the children. The results allude to the intervention merely ‘keeping active children active’ via (mostly) fun, football sessions. Results highlight the important contribution the ‘coach’ plays in the effectiveness of the intervention. Results relating to working practice (i.e. coaching practice and coach recruitment) are discussed and highlighted as areas to be addressed. FitC schemes appear to require a process of positive organizational change to increase their effectiveness in strategically attending to the health agenda

    The early evolution of the H-free process

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    The H-free process, for some fixed graph H, is the random graph process defined by starting with an empty graph on n vertices and then adding edges one at a time, chosen uniformly at random subject to the constraint that no H subgraph is formed. Let G be the random maximal H-free graph obtained at the end of the process. When H is strictly 2-balanced, we show that for some c>0, with high probability as n→∞n \to \infty, the minimum degree in G is at least cn1−(vH−2)/(eH−1)(log⁥n)1/(eH−1)cn^{1-(v_H-2)/(e_H-1)}(\log n)^{1/(e_H-1)}. This gives new lower bounds for the Tur\'an numbers of certain bipartite graphs, such as the complete bipartite graphs Kr,rK_{r,r} with r≄5r \ge 5. When H is a complete graph KsK_s with s≄5s \ge 5 we show that for some C>0, with high probability the independence number of G is at most Cn2/(s+1)(log⁥n)1−1/(eH−1)Cn^{2/(s+1)}(\log n)^{1-1/(e_H-1)}. This gives new lower bounds for Ramsey numbers R(s,t) for fixed s≄5s \ge 5 and t large. We also obtain new bounds for the independence number of G for other graphs H, including the case when H is a cycle. Our proofs use the differential equations method for random graph processes to analyse the evolution of the process, and give further information about the structure of the graphs obtained, including asymptotic formulae for a broad class of subgraph extension variables.Comment: 36 page

    Come back Marshall, all is forgiven? : Complexity, evolution, mathematics and Marshallian exceptionalism

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    Marshall was the great synthesiser of neoclassical economics. Yet with his qualified assumption of self-interest, his emphasis on variation in economic evolution and his cautious attitude to the use of mathematics, Marshall differs fundamentally from other leading neoclassical contemporaries. Metaphors inspire more specific analogies and ontological assumptions, and Marshall used the guiding metaphor of Spencerian evolution. But unfortunately, the further development of a Marshallian evolutionary approach was undermined in part by theoretical problems within Spencer's theory. Yet some things can be salvaged from the Marshallian evolutionary vision. They may even be placed in a more viable Darwinian framework.Peer reviewedFinal Accepted Versio

    Narrow genetic base in forest restoration with holm oak (Quercus ilex L.) in Sicily

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    In order to empirically assess the effect of actual seed sampling strategy on genetic diversity of holm oak (Quercus ilex) forestations in Sicily, we have analysed the genetic composition of two seedling lots (nursery stock and plantation) and their known natural seed origin stand by means of six nuclear microsatellite loci. Significant reduction in genetic diversity and significant difference in genetic composition of the seedling lots compared to the seed origin stand were detected. The female and the total effective number of parents were quantified by means of maternity assignment of seedlings and temporal changes in allele frequencies. Extremely low effective maternity numbers were estimated (Nfe ≈\approx 2-4) and estimates accounting for both seed and pollen donors gave also low values (Ne ≈\approx 35-50). These values can be explained by an inappropriate forestry seed harvest strategy limited to a small number of spatially close trees
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