46,330 research outputs found
Corrosion and wear in moulding boxes
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
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
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
is large but not necessarily infinite. Specifically, we consider an asymptotic
expansion of the two-locus sampling formula in inverse powers of 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
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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