1,467 research outputs found
Propionibacterium avidum infection following breast reduction: high morbidity from a low-virulence pathogen
Propionibacterium avidum is a common inhabitant of sebaceous glands, traditionally considered to be of low virulence and generally found on implanted foreign material. We report a rare case of P. avidum breast abscess, causing severe morbidity following breast reduction surgery. A 36-year-old woman presented with a non-painful wound discharge 3 weeks postoperatively, and was treated conservatively. She was readmitted 7 weeks postoperatively with a red and tender breast. A purulent discharging abscess was drained under ultrasound guidance. A 2-week intravenous course of amoxicillin-clavulanic acid, followed by oral replacement for a month resulted effective. Serial ultrasound imaging was useful in treatment decision-making. The infective potential of P. avidum may be underappreciated. Proximity of sutures to the axilla, tobacco smoking and the potential for resorbable sutures to host bacteria may predispose to infection, and should raise the clinician's awareness
Environmental fluctuations accelerate molecular evolution of thermal tolerance in a marine diatom
This is the final version of the article. Available from Springer Nature via the DOI in this recordThe publisher correction to this article is in ORE at: http://hdl.handle.net/10871/34487Diatoms contribute roughly 20% of global primary production, but the factors determining their ability to adapt to global warming are unknown. Here we quantify the capacity for adaptation to warming in the marine diatom Thalassiosira pseudonana. We find that evolutionary rescue under severe (32 °C) warming is slow, but adaptation to more realistic scenarios where temperature increases are moderate (26 °C) or fluctuate between benign and severe conditions is rapid and linked to phenotypic changes in metabolic traits and elemental composition. Whole-genome re-sequencing identifies genetic divergence among populations selected in the different warming regimes and between the evolved and ancestral lineages. Consistent with the phenotypic changes, the most rapidly evolving genes are associated with transcriptional regulation, cellular responses to oxidative stress and redox homeostasis. These results demonstrate that the evolution of thermal tolerance in marine diatoms can be rapid, particularly in fluctuating environments, and is underpinned by major genomic and phenotypic change.This study was funded by a Leverhulme Trust research grant (RPG-2013-335). Whole genome re-sequencing was carried out at Exeter Sequencing Service and Computational core facilities at the University of Exeter, where Dr. Karen Moore, Dr. Audrey Farbos, Paul O’Neill, and Dr. Konrad Paszkiewicz lead the handling of the samples. Exeter Squencing Services are supported by Medical Research Council Clinical Infrastructure award (MR/M008924/1), Wellcome Trust Institutional Strategic Support Fund (WT097835MF), Wellcome Trust Multi User Equipment Award (WT101650MA), and BBSRC LOLA award (BB/K003240/1)
Kinetic theory of point vortex systems from the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy
Kinetic equations are derived from the Bogoliubov-Born-Green-Kirkwood-Yvon
(BBGKY) hierarchy for point vortex systems in an infinite plane. As the level
of approximation for the Landau equation, the collision term of the kinetic
equation derived coincides with that by Chavanis ({\it Phys. Rev. E} {\bf 64},
026309 (2001)). Furthermore, we derive a kinetic equation corresponding to the
Balescu-Lenard equation for plasmas, using the theory of the Fredholm integral
equation. For large , this kinetic equation is reduced to the Landau
equation above.Comment: 10 pages, No figures. To be published in Physical Review E, 76-
Publisher Correction: Environmental fluctuations accelerate molecular evolution of thermal tolerance in a marine diatom
The article for which this is the publisher correction is in ORE at: http://hdl.handle.net/10871/32652The PDF version of this Article was updated shortly after publication following an error which resulted in the Φ symbol being omitted from the left hand side of equation 8. The HTML version was correct from the time of publication
Statistical approach to dislocation dynamics: From dislocation correlations to a multiple-slip continuum plasticity theory
Due to recent successes of a statistical-based nonlocal continuum crystal
plasticity theory for single-glide in explaining various aspects such as
dislocation patterning and size-dependent plasticity, several attempts have
been made to extend the theory to describe crystals with multiple slip systems
using ad-hoc assumptions. We present here a mesoscale continuum theory of
plasticity for multiple slip systems of parallel edge dislocations. We begin by
constructing the Bogolyubov-Born-Green-Yvon-Kirkwood (BBGYK) integral equations
relating different orders of dislocation correlation functions in a grand
canonical ensemble. Approximate pair correlation functions are obtained for
single-slip systems with two types of dislocations and, subsequently, for
general multiple-slip systems of both charges. The effect of the correlations
manifests itself in the form of an entropic force in addition to the external
stress and the self-consistent internal stress. Comparisons with a previous
multiple-slip theory based on phenomenological considerations shall be
discussed.Comment: 12 pages, 3 figure
A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments
Most speech and language technologies are trained with massive amounts of
speech and text information. However, most of the world languages do not have
such resources or stable orthography. Systems constructed under these almost
zero resource conditions are not only promising for speech technology but also
for computational language documentation. The goal of computational language
documentation is to help field linguists to (semi-)automatically analyze and
annotate audio recordings of endangered and unwritten languages. Example tasks
are automatic phoneme discovery or lexicon discovery from the speech signal.
This paper presents a speech corpus collected during a realistic language
documentation process. It is made up of 5k speech utterances in Mboshi (Bantu
C25) aligned to French text translations. Speech transcriptions are also made
available: they correspond to a non-standard graphemic form close to the
language phonology. We present how the data was collected, cleaned and
processed and we illustrate its use through a zero-resource task: spoken term
discovery. The dataset is made available to the community for reproducible
computational language documentation experiments and their evaluation.Comment: accepted to LREC 201
Interacting Constituents in Cosmology
Universe evolution, as described by Friedmann's equations, is determined by
source terms fixed by the choice of pressure energy-density equations
of state . The usual approach in Cosmology considers equations of
state accounting only for kinematic terms, ignoring the contribution from the
interactions between the particles constituting the source fluid. In this work
the importance of these neglected terms is emphasized. A systematic method,
based on the Statistical Mechanics of real fluids, is proposed to include them.
A toy-model is presented which shows how such interaction terms can engender
significant cosmological effects.Comment: 24 pages, 6 figures. It includes results presented in "Cosmic
Acceleration from Elementary Interactions" [arXiv:gr-qc/0512135]. Citations
added in v.
Electro-purification studies and first measurement of relative permittivity of TMBi
A new type of detector for positron-emission tomography (PET) has been
proposed recently, using a heavy organo-metallic liquid - TriMethyl Bismuth
(TMBi) - as target material. TMBi is a transparent liquid with the high Z
element Bismuth contributing 82% of its mass. 511keV annihilation photons are
converted efficiently into photo-electrons within the detector material
producing both Cherenkov light and free charge carriers in the liquid. While
the optical component enables a fast timing, a charge readout using a segmented
anode can provide an accurate position reconstruction and energy determination.
The charge measurement requires a high level of purification, as any
electronegative contaminants cause signal degradation. In addition to the
purity requirements, the reactive nature of TMBi poses many challenges that
need to be met until a fully functioning detector for PET applications can be
realized. The paper presents an experimental setup that aims to remove
electronegative impurities by electrostatic filtering and to characterise the
properties of TMBi, e.g. the relative permittivity, for its application as a
detector medium for charge read out
A Comparison of Algorithms for the Construction of SZ Cluster Catalogues
We evaluate the construction methodology of an all-sky catalogue of galaxy
clusters detected through the Sunyaev-Zel'dovich (SZ) effect. We perform an
extensive comparison of twelve algorithms applied to the same detailed
simulations of the millimeter and submillimeter sky based on a Planck-like
case. We present the results of this "SZ Challenge" in terms of catalogue
completeness, purity, astrometric and photometric reconstruction. Our results
provide a comparison of a representative sample of SZ detection algorithms and
highlight important issues in their application. In our study case, we show
that the exact expected number of clusters remains uncertain (about a thousand
cluster candidates at |b|> 20 deg with 90% purity) and that it depends on the
SZ model and on the detailed sky simulations, and on algorithmic implementation
of the detection methods. We also estimate the astrometric precision of the
cluster candidates which is found of the order of ~2 arcmins on average, and
the photometric uncertainty of order ~30%, depending on flux.Comment: Accepted for publication in A&A: 14 pages, 7 figures. Detailed
figures added in Appendi
Visibility diagrams and experimental stripe structure in the quantum Hall effect
We analyze various properties of the visibility diagrams that can be used in
the context of modular symmetries and confront them to some recent experimental
developments in the Quantum Hall Effect. We show that a suitable physical
interpretation of the visibility diagrams which permits one to describe
successfully the observed architecture of the Quantum Hall states gives rise
naturally to a stripe structure reproducing some of the experimental features
that have been observed in the study of the quantum fluctuations of the Hall
conductance. Furthermore, we exhibit new properties of the visibility diagrams
stemming from the structure of subgroups of the full modular group.Comment: 8 pages in plain TeX, 7 figures in a single postscript fil
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