46,330 research outputs found

    Editorial

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    Editorial

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    Editorial

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    Editorial

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    Editorial

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    Corrosion and wear in moulding boxes

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    We assess the potential causes of damage to mould box ends and find that both HOT corrosion, due to burning of emitted volatiles, and COLD corrosion, due to the presence of high humidity (and possibly high chloride ion concentration), are likely to contribute to the damage. We suggest strategies to minimise the damage, including venting of the volatiles, ventilation of the pallet grooves during cooling and minimisation of brushing effects during cleaning. Some calculations are described in an attempt to quantify the various effects discussed, but we are unable to accurately estimate their significance

    Naturalness of the Coleman-Glashow Mass Relation in the 1/N_c Expansion: an Update

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    A new measurement of the Xi^0 mass verifies the accuracy of the Coleman-Glashow relation at the level predicted by the 1/N_c expansion. Values for other baryon isospin mass splittings are updated, and continue to agree with the 1/N_c hierarchy.Comment: 6 pages, revte

    An asymptotic sampling formula for the coalescent with Recombination

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    Ewens sampling formula (ESF) is a one-parameter family of probability distributions with a number of intriguing combinatorial connections. This elegant closed-form formula first arose in biology as the stationary probability distribution of a sample configuration at one locus under the infinite-alleles model of mutation. Since its discovery in the early 1970s, the ESF has been used in various biological applications, and has sparked several interesting mathematical generalizations. In the population genetics community, extending the underlying random-mating model to include recombination has received much attention in the past, but no general closed-form sampling formula is currently known even for the simplest extension, that is, a model with two loci. In this paper, we show that it is possible to obtain useful closed-form results in the case the population-scaled recombination rate ρ\rho is large but not necessarily infinite. Specifically, we consider an asymptotic expansion of the two-locus sampling formula in inverse powers of ρ\rho and obtain closed-form expressions for the first few terms in the expansion. Our asymptotic sampling formula applies to arbitrary sample sizes and configurations.Comment: Published in at http://dx.doi.org/10.1214/09-AAP646 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Past plant use in Jordan as revealed by archaeological and ethnoarchaeological phytolith signatures

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    Ninety-six phytolith samples were analysed from seven archaeological sites ranging from the Pre-Pottery Neolithic to the Classical period and from two ethnoarchaeological sites in Jordan. The aims were to test the possibility of detecting past irrigation with the methodology outlined by Madella et al. (2009) and Jenkins et al. (Chapter 21, this volume) and to study the contextual and temporal variation of plant use in Jordan. We utilised a water availability index using the proportion of phytolith types and ordination statistical methods to explore the similarities between the phytolith assemblages. The result of applying the irrigation methodology was promising, with contexts from water channels showing the greatest indication of water availability. Changes in plant use through time were also apparent with regard to phytolith densities and taxonomy. Date palm was identified in the Pottery Neolithic, providing one of the earliest records for this taxon in Jordan. This study shows the potential of both the water availability index and the value of inter-site comparison of phytolith assemblages
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