6,896 research outputs found
The Specific Heat of a Ferromagnetic Film.
We analyze the specific heat for the vector model on a -dimensional
film geometry of thickness using ``environmentally friendly''
renormalization. We consider periodic, Dirichlet and antiperiodic boundary
conditions, deriving expressions for the specific heat and an effective
specific heat exponent, \alpha\ef. In the case of , for , by
matching to the exact exponent of the two dimensional Ising model we capture
the crossover for \xi_L\ra\infty between power law behaviour in the limit
{L\over\xi_L}\ra\infty and logarithmic behaviour in the limit
{L\over\xi_L}\ra0 for fixed , where is the correlation length in
the transverse dimensions.Comment: 21 pages of Plain TeX. Postscript figures available upon request from
[email protected]
Use of whole genome sequencing of commensal Escherichia coli in pigs for antimicrobial resistance surveillance, United Kingdom, 2018
BackgroundSurveillance of commensal Escherichia coli, a possible reservoir of antimicrobial resistance (AMR) genes, is important as they pose a risk to human and animal health. Most surveillance activities rely on phenotypic characterisation, but whole genome sequencing (WGS) presents an alternative.AimIn this retrospective study, we tested 515 E. coli isolated from pigs to evaluate the use of WGS to predict resistance phenotype.MethodsMinimum inhibitory concentration (MIC) was determined for nine antimicrobials of clinical and veterinary importance. Deviation from wild-type, fully-susceptible MIC was assessed using European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off (ECOFF) values. Presence of AMR genes and mutations were determined using APHA SeqFinder. Statistical two-by-two table analysis and Cohen's kappa (k) test were applied to assess genotype and phenotype concordance.ResultsOverall, correlation of WGS with susceptibility to the nine antimicrobials was 98.9% for test specificity, and 97.5% for the positive predictive value of a test. The overall kappa score (k = 0.914) indicated AMR gene presence was highly predictive of reduced susceptibility and showed excellent correlation with MIC. However, there was variation for each antimicrobial; five showed excellent correlation; four very good and one moderate. Suggested ECOFF adjustments increased concordance between genotypic data and kappa values for four antimicrobials.ConclusionWGS is a powerful tool for accurately predicting AMR that can be used for national surveillance purposes. Additionally, it can detect resistance genes from a wider panel of antimicrobials whose phenotypes are currently not monitored but may be of importance in the future
Higher Order Correlations in Quantum Chaotic Spectra
The statistical properties of the quantum chaotic spectra have been studied,
so far, only up to the second order correlation effects. The numerical as well
as the analytical evidence that random matrix theory can successfully model the
spectral fluctuatations of these systems is available only up to this order.
For a complete understanding of spectral properties it is highly desirable to
study the higher order spectral correlations. This will also inform us about
the limitations of random matrix theory in modelling the properties of quantum
chaotic systems. Our main purpose in this paper is to carry out this study by a
semiclassical calculation for the quantum maps; however results are also valid
for time-independent systems.Comment: Revtex, Four figures (Postscript files), Phys. Rev E (in press
Dimensional Crossover in the Large N Limit
We consider dimensional crossover for an Landau-Ginzburg-Wilson model
on a -dimensional film geometry of thickness in the large -limit. We
calculate the full universal crossover scaling forms for the free energy and
the equation of state. We compare the results obtained using ``environmentally
friendly'' renormalization with those found using a direct, non-renormalization
group approach. A set of effective critical exponents are calculated and
scaling laws for these exponents are shown to hold exactly, thereby yielding
non-trivial relations between the various thermodynamic scaling functions.Comment: 25 pages of PlainTe
Phase 1 Research Report on the IMPRESS Health 2 (Interreg IVA Channel Programme) Project 4282: Understanding the factors behind the late testing and diagnosis of HIV
This report outlines Phase 1 data from an EU Interreg IVA Channel Programme funded research project (Number 4282) conducted to understand factors behind the late testing and diagnosis of HIV in Kent and Medway (UK). The views of patients or service users (n=37) and health care professionals (n=16) on the barriers to early HIV testing and diagnosis were elicited in a series of semi-structured interviews across three organisations providing HIV testing in Kent and Medway between January and March 2014. A retrospective analysis of all patients diagnosed with HIV between January 2008 and December 2013 (n=242) in those centres was also conducted to identify the proportion of early and late presenters in each organisation and identify any correlating factors which may have impacted upon an individual's likelihood of being diagnosed late (i.e. with a CD4 count <350). Chief among the recommendations for a Phase 2 intervention study were the need for improved education and training of healthcare staff (particularly in primary care) to elicit individual's concerns about HIV risk and address stereotypical ideas that it is a condition which predominantly affects men who have sex with men or particular immigrant populations. The data showed that white heterosexuals, and in particular, white women were at particular risk of having their HIV diagnosed late in the region. The second recommendation for immediate action was the need for a concerted social media and public health campaign aimed at 'atypical' HIV patient groups in order to raise awareness of HIV transmission risk and the benefits of early testing and diagnosis
Two new species of Marmosopus (Acari: Astigmata) from rodents of the genus Scotinomys (Cricetidae) in Central America
http://deepblue.lib.umich.edu/bitstream/2027.42/57139/1/OP703.pd
The scaling region of the lattice O(N) sigma model at finite temperature
We present results from numerical studies of the finite temperature phase
transition of the O(N)-symmetric non-linear sigma model for
and 3. We study the dependence of the width of the 3d critical region on
and we show that the broken phase scaling region is much wider for N=2 and 3
than for N=1. We also compare the widths of the critical region in the low
and high phases of the O(2) model and we show that the scaling region in
the broken phase is much wider than in the symmetric phase. We also report
results for the width of the scaling regions in the low phase
Ising model and we show that the spatial correlation length has to be
approximately twice the lattice temporal extent before the 2d scaling region is
reached.Comment: 17 pages, 7 figure
Candidates for giant lobes projecting from the LBV stars P Cygni and R 143
Deep, wide-field, continuum-subtracted, images in the light of the
Halpha+[NII] 6548 & 6584 A and [O III] 5007 A nebular emission lines have been
obtained of the environment of the Luminous Blue Variable (LBV) star P Cygni. A
previously discovered, receding, nebulous filament along PA 50 deg has now been
shown to extend up to 12' from this star. Furthermore, in the light of [O III]
5007 A, a southern counterpart is discovered as well as irregular filaments on
the opposite side of P Cygni.
Line profiles from this nebulous complex indicate that this extended
nebulosity is similar to that associated with middle-aged supernova remnants.
However, there are several indications that it has originated in P Cygni and is
not just a chance superposition along the same sight-line. This possibility is
explored here and comparison is made with a new image of the LBV star R 143 in
the LMC from which similar filaments appear to project.
The dynamical age of the P Cygni giant lobe of ~5x10^{4} yr is consistent
with both the predicted and observed durations of the LBV phases of 50M stars
after they have left the main sequence. Its irregular shape may have been
determined by the cavity formed in the ambient gas by the energetic wind of the
star, and shaped by a dense torus, when on the main sequence.
The proper motion and radial velocity of P Cygni, with respect to its local
environment, could explain the observed angular and kinematical shifts of the
star compared with the giant lobe.Comment: 7 pages, 3 figures, accepted for publication in A&
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