29,922 research outputs found
Addressing data management training needs: a practice based approach from the UK
In this paper, we describe the current challenges to the effective management and preservation of research data in UK universities, and the response provided by the JISC Managing Research Data programme.
This paper will discuss, inter alia, the findings and conclusions from data management training projects of the first iteration of the programme and how they informed the design of the second, paying particular attention to initiatives to develop and embed training materials
Remark on the (Non)convergence of Ensemble Densities in Dynamical Systems
We consider a dynamical system with state space , a smooth, compact subset
of some , and evolution given by , , ;
is invertible and the time may be discrete, , , or continuous, . Here we show that starting with a
continuous positive initial probability density , with respect
to , the smooth volume measure induced on by Lebesgue measure on , the expectation value of , with respect to any
stationary (i.e. time invariant) measure , is linear in , . depends only on and vanishes
when is absolutely continuous wrt .Comment: 7 pages, plain TeX; [email protected],
[email protected], [email protected], to appear in Chaos: An
Interdisciplinary Journal of Nonlinear Science, Volume 8, Issue
Molecular studies on intraspecific diversity and phylogenetic position of Coniothyrium minitans
Simple sequence repeat (SSR)±PCR amplification using a microsatellite primer (GACA)% and ribosomal RNA gene sequencing were used to examine the intraspecific diversity in the mycoparasite Coniothyrium minitans based on 48 strains, representing eight colony types, from 17 countries world-wide. Coniothyrium cerealis, C. fuckelii and C. sporulosum were used for interspecific comparison. The SSR±PCR technique revealed a relatively low level of polymorphism within C. minitans but did allow some differentiation between strains. While there was no relationship between SSR±PCR profiles and colony type, there was some limited correlation between these profiles and country of origin. Sequences of the ITS 1 and ITS 2 regions and the 5±8S gene of rRNA genes were identical in all twenty-four strains of C. minitans examined irrespective of colony type and origin. These results indicate that C. minitans is genetically not very variable despite phenotypic differences. ITS and 5±8S rRNA gene sequence analyses showed that C. minitans had similarities of 94% with C. fuckelii and C. sporulosum (which were identical to each other) and only 64% with C. cerealis. Database searches failed to show any similarity with the ITS 1 sequence for C. minitans although the 5±8S rRNA gene and ITS 2 sequences revealed an 87% similarity with Aporospora terricola. The ITS sequence including the 5±8S rRNA gene sequence of Coniothyrium cerealis showed 91% similarity to Phaeosphaeria microscopica. Phylogenetic analyses using database information suggest that C. minitans, C. sporulosum, C. fuckelii and A. terricola cluster in one clade, grouping with Helminthosporium species and 'Leptosphaeria' bicolor. Coniothyrium cerealis grouped with Ampelomyces quisqualis and formed a major cluster with members of the Phaeosphaeriacae and Phaeosphaeria microscopica
Shift Equivalence of Measures and the Intrinsic Structure of Shocks in the Asymmetric Simple Exclusion Process
We investigate properties of non-translation-invariant measures, describing
particle systems on \bbz, which are asymptotic to different translation
invariant measures on the left and on the right. Often the structure of the
transition region can only be observed from a point of view which is
random---in particular, configuration dependent. Two such measures will be
called shift equivalent if they differ only by the choice of such a viewpoint.
We introduce certain quantities, called translation sums, which, under some
auxiliary conditions, characterize the equivalence classes. Our prime example
is the asymmetric simple exclusion process, for which the measures in question
describe the microscopic structure of shocks. In this case we compute
explicitly the translation sums and find that shocks generated in different
ways---in particular, via initial conditions in an infinite system or by
boundary conditions in a finite system---are described by shift equivalent
measures. We show also that when the shock in the infinite system is observed
from the location of a second class particle, treating this particle either as
a first class particle or as an empty site leads to shift equivalent shock
measures.Comment: Plain TeX, 2 figures; [email protected], [email protected],
[email protected], [email protected]
Seven Steps Towards the Classical World
Classical physics is about real objects, like apples falling from trees,
whose motion is governed by Newtonian laws. In standard Quantum Mechanics only
the wave function or the results of measurements exist, and to answer the
question of how the classical world can be part of the quantum world is a
rather formidable task. However, this is not the case for Bohmian mechanics,
which, like classical mechanics, is a theory about real objects. In Bohmian
terms, the problem of the classical limit becomes very simple: when do the
Bohmian trajectories look Newtonian?Comment: 16 pages, LaTeX, uses latexsy
On the (Boltzmann) Entropy of Nonequilibrium Systems
Boltzmann defined the entropy of a macroscopic system in a macrostate as
the of the volume of phase space (number of microstates) corresponding
to . This agrees with the thermodynamic entropy of Clausius when
specifies the locally conserved quantities of a system in local thermal
equilibrium (LTE). Here we discuss Boltzmann's entropy, involving an
appropriate choice of macro-variables, for systems not in LTE. We generalize
the formulas of Boltzmann for dilute gases and of Resibois for hard sphere
fluids and show that for macro-variables satisfying any deterministic
autonomous evolution equation arising from the microscopic dynamics the
corresponding Boltzmann entropy must satisfy an -theorem.Comment: 31 pages, in Tex, authors' e-mails: [email protected],
[email protected]
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