571 research outputs found
Prevalence and characterization of human mecC methicillin-resistant Staphylococcus aureus isolates in England
Objectives: There are limited data available on the epidemiology and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the human population that encode the recently described mecA homologue, mecC. To address this knowledge gap we undertook a prospective prevalence study in England to determine the prevalence of mecC among MRSA isolates.<p></p>
Patients and methods: Three hundred and thirty-five sequential MRSA isolates from individual patients were collected from each of six clinical microbiology laboratories in England during 2011–12. These were tested by PCR or genome sequencing to differentiate those encoding mecA and mecC. mecC-positive isolates were further characterized by multilocus sequence typing, spa typing, antimicrobial susceptibility profile and detection of PBP2a using commercially available kits.<p></p>
Results: Nine out of the 2010 MRSA isolates tested were mecC positive, indicating a prevalence among MRSA in England of 0.45% (95% CI 0.24%–0.85%). The remainder were mecA positive. Eight out of these nine mecC MRSA isolates belonged to clonal complex 130, the other being sequence type 425. Resistance to non-β-lactam antibiotics was rare among these mecC MRSA isolates and all were phenotypically identified as MRSA using oxacillin and cefoxitin according to BSAC disc diffusion methodology. However, all nine mecC isolates gave a negative result using three different commercial PBP2a detection assays.
Conclusions: mecC MRSA are currently rare among MRSA isolated from humans in England and this study provides an important baseline prevalence rate to monitor future changes, which may be important given the increasing prevalence of mecC MRSA reported in Denmark.<p></p>
Feasibility and safety of combining repetitive transcranial magnetic stimulation and quadriceps strengthening exercise for chronic pain in knee osteoarthritis: A study protocol for a pilot randomised controlled trial
Introduction Knee osteoarthritis is a leading cause of disability, resulting in pain and reduced quality of life. Exercise is the cornerstone of conservative management but effects are, at best, moderate. Early evidence suggests that repetitive transcranial magnetic stimulation (rTMS) applied over the primary motor cortex (M1) may improve the effect of exercise in knee osteoarthritis. This pilot study aims to (1) determine the feasibility, safety and participant-rated response to an intervention adding M1 rTMS to exercise in knee osteoarthritis; (2) elucidate physiological mechanisms in response to the intervention; (3) provide data to conduct a sample size calculation for a fully powered trial. Methods and analysis This is a pilot randomised, assessor-blind, therapist-blind and participant-blind, sham-controlled trial. Thirty individuals with painful knee osteoarthritis will be recruited and randomly allocated to receive either: (1) active rTMS+exercise or (2) sham rTMS+exercise intervention. Participants will receive 15 min of either active or sham rTMS immediately prior to 30 min of supervised muscle strengthening exercise (2×/week, 6 weeks) and complete unsupervised home exercises. Outcome measures of feasibility, safety, pain, function and physiological mechanisms will be assessed before and/or after the intervention. Feasibility and safety will be analysed using descriptive analysis. Within-group and between-group comparisons of pain and function will be conducted to examine trends of efficacy. Ethics and dissemination This study has been approved by the University of New South Wales Human Research Ethics Committee (HC210954). All participants will provide written informed consent. The study results will be submitted for peer-reviewed publication. Trial registration number ACTRN12621001712897p
Connecting Leptogenesis to CP Violation in Neutrino Mixings in a Tri-bimaximal Mixing model
We show that in a recently proposed model for tri-bimaximal mixing
pattern for neutrinos, CP violating phases in neutrino mixings are directly
responsible for lepton asymmetry . In the exact tri-bimaximal
limit, is proportional to one of the Majorana phases whereas in
the presence of small deviations from tri-bimaximal pattern, there are two
contributions, one being proportional to the Dirac phase and the other to one
of the two Majorana phases. In the second case, is nonzero and
correlated with the deviation from maximal atmospheric mixing.Comment: 14 pages; no figures; references update
Validation of the DECAF score to predict hospital mortality in acute exacerbations of COPD
Background
Hospitalisation due to acute
exacerbations of COPD (AECOPD) is common, and
subsequent mortality high. The DECAF score was derived
for accurate prediction of mortality and risk strati
fi
cation
to inform patient care. We aimed to validate the DECAF
score, internally and externally, and to compare its
performance to other predictive tools.
Methods
The study took place in the two hospitals
within the derivation study (internal validation) and in
four additional hospitals (external validation) between
January 2012 and May 2014. Consecutive admissions
were identi
fi
ed by screening admissions and searching
coding records. Admission clinical data, including DECAF
indices, and mortality were recorded. The prognostic
value of DECAF and other scores were assessed by the
area under the receiver operator characteristic (AUROC)
curve.
Results
In the internal and external validation cohorts,
880 and 845 patients were recruited. Mean age was
73.1 (SD 10.3) years, 54.3% were female, and mean
(SD) FEV
1
45.5 (18.3) per cent predicted. Overall
mortality was 7.7%. The DECAF AUROC curve for
inhospital mortality was 0.83 (95% CI 0.78 to 0.87) in
the internal cohort and 0.82 (95% CI 0.77 to 0.87) in
the external cohort, and was superior to other
prognostic scores for inhospital or 30-day mortality.
Conclusions
DECAF is a robust predictor of mortality,
using indices routinely available on admission. Its
generalisability is supported by consistent strong
performance; it can identify low-risk patients (DECAF
0
–
1) potentially suitable for Hospital at Home or early
supported discharge services, and high-risk patients
(DECAF 3
–
6) for escalation planning or appropriate early
palliation.
Trial registration number
UKCRN ID 14214
Tri-Bimaximal Mixing from Twisted Friedberg-Lee Symmetry
We investigate the Friedberg-Lee (FL) symmetry and its promotion to include
the symmetry, and call that the twisted FL symmetry.Based on the
twisted FL symmetry, two possible schemes are presented toward the realistic
neutrino mass spectrum and the tri-bimaximal mixing.In the first scheme, we
suggest the semi-uniform translation of the FL symmetry.The second one is based
on the permutation family symmetry.The breaking terms, which are twisted
FL symmetric, are introduced.Some viable models in each scheme are also
presented.Comment: 14 pages, no figure. v2: 16 pages, modified some sentences, appendix
added, references added. v3: 14 pages, composition simplified, accepted
version in EPJ
Energy Independent Solution to the Solar Neutrino Anomaly including the SNO data
The global data on solar neutrino rates and spectrum, including the SNO
charged current rate, can be explained by LMA, LOW or the energy independent
solution -- corresponding to near-maximal mixing. All the three favour a mild
upward renormalisation of the Cl rate. A mild downward shift of the
neutrino flux is favoured by the energy independent and to a lesser extent the
LOW solution, but not by LMA. Comparison with the ratio of SK elastic and SNO
charged current scattering rates favours the LMA over the other two solutions,
but by no more than .Comment: 18 pages, latex, 3 figure
Scaling in the Neutrino Mass Matrix
In an attempt to uncover any underlying structure in the neutrino mass
matrix, we discuss the possibility that the ratios of elements of its Majorana
mass matrix are equal. We call this "strong scaling Ansatz" for neutrino masses
and study its phenomenological implications. Of three possible independent
scale invariant possibilities, only one is allowed by current data, predicting
in a novel way the vanishing of U_{e3} and an inverted hierarchy with the
lightest neutrino having zero mass. The Ansatz has the additional virtue that
it is not affected by renormalization running. We also discuss explicit models
in which the scaling Ansatz is realized.Comment: 13 pages, 2 figures. To appear in PL
'Mu-Tau' symmetry, tribimaximal mixing and four zero neutrino Yukawa textures
Within the type-I seesaw framework with three heavy right chiral neutrinos
and in the basis where the latter and the charged leptons are mass diagonal, a
near `mu-tau' symmetry in the neutrino sector is strongly suggested by the
neutrino oscillation data. There is further evidence for a close to the
tribimaximal mixing pattern which subsumes `mu-tau' symmetry. On the other
hand, the assumption of a (maximally allowed) four zero texture in the Yukawa
coupling matrix Y_nu in the same basis leads to a highly constrained and
predictive theoretical scheme. We show that the requirement of an exact
`mu-tau' symmetry, coupled with observational constraints, reduces the `seventy
two' allowed textures in such a `Y_nu' to 'only four' corresponding to just two
different forms of the light neutrino mass matrix `m_nu'. The effect of each of
these on measurable quantities can be described, apart from an overall factor
of the neutrino mass scale, in terms of two real parameters and a phase angle
all of which are within very constrained ranges. The additional input of a
tribimaximal mixing reduces these three parameters to `only one' with a very
nearly fixed value. Implications for both flavored and unflavored leptogenesis
as well as radiative lepton flavor violating decays are discussed. We also
investigate the stability of these conclusions under small deviations due to
renormalization group running from a high scale where the four zero texture as
well as `mu-tau' symmetry or the tribimaximal mixing pattern are imposed.Comment: Typographical changes,accepted for publication in JHE
Renormalization Group Running of Lepton Mixing Parameters in See-Saw Models with Flavor Symmetry
We study the renormalization group running of the tri-bimaximal mixing
predicted by the two typical flavor models at leading order. Although the
textures of the mass matrices are completely different, the evolution of
neutrino mass and mixing parameters is found to display approximately the same
pattern. For both normal hierarchy and inverted hierarchy spectrum, the quantum
corrections to both atmospheric and reactor neutrino mixing angles are so small
that they can be neglected. The evolution of the solar mixing angle
depends on and neutrino mass spectrum, the deviation
from its tri-bimaximal value could be large. Taking into account the
renormalization group running effect, the neutrino spectrum is constrained by
experimental data on in addition to the self-consistency
conditions of the models, and the inverted hierarchy spectrum is disfavored for
large . The evolution of light-neutrino masses is approximately
described by a common scaling factor.Comment: 23 pages, 6figure
MSLED, Neutrino Oscillations and the Cosmological Constant
We explore the implications for neutrino masses and mixings within the
minimal version of the supersymmetric large-extra-dimensions scenario (MSLED).
This model was proposed in {\tt hep-ph/0404135} to extract the phenomenological
implications of the promising recent attempt (in {\tt hep-th/0304256}) to
address the cosmological constant problem. Remarkably, we find that the
simplest couplings between brane and bulk fermions within this approach can
lead to a phenomenologically-viable pattern of neutrino masses and mixings that
is also consistent with the supernova bounds which are usually the bane of
extra-dimensional neutrino models. Under certain circumstances the MSLED
scenario can lead to a lepton mixing (PMNS) matrix close to the so-called
bi-maximal or the tri-bimaximal forms (which are known to provide a good
description of the neutrino oscillation data). We discuss the implications of
MSLED models for neutrino phenomenology.Comment: 38 pages, 1 figure; Reposted with a few additional reference
- …