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&gt

Herschel-ATLAS: The angular correlation function of submillimetre galaxies at high and low redshift

Original article can be found at: http://www.aanda.org/ Copyright The European Southern ObservatoryWe present measurements of the angular correlation function of galaxies selected from the first field of the H-ATLAS survey. Careful removal of the background from galactic cirrus is essential, and currently dominates the uncertainty in our measurements. For our 250 μm-selected sample we detect no significant clustering, consistent with the expectation that the 250 μm-selected sources are mostly normal galaxies at z 1. For our 350 μm and 500 μm-selected samples we detect relatively strong clustering with correlation amplitudes A of 0.2 and 1.2 at 1', but with relatively large uncertainties. For samples which preferentially select high redshift galaxies at z~2–3 we detect significant strong clustering, leading to an estimate of r0 ~ 7–11 h-1 Mpc. The slope of our clustering measurements is very steep, δ ~ 2. The measurements are consistent with the idea that sub-mm sources consist of a low redshift population of normal galaxies and a high redshift population of highly clustered star-bursting galaxies.Peer reviewe

Large Scale Structures in Kinetic Gravity Braiding Model That Can Be Unbraided

We study cosmological consequences of a kinetic gravity braiding model, which is proposed as an alternative to the dark energy model. The kinetic braiding model we study is characterized by a parameter n, which corresponds to the original galileon cosmological model for n=1. We find that the background expansion of the universe of the kinetic braiding model is the same as the Dvali-Turner's model, which reduces to that of the standard cold dark matter model with a cosmological constant (LCDM model) for n equal to infinity. We also find that the evolution of the linear cosmological perturbation in the kinetic braiding model reduces to that of the LCDM model for n=\infty. Then, we focus our study on the growth history of the linear density perturbation as well as the spherical collapse in the nonlinear regime of the density perturbations, which might be important in order to distinguish between the kinetic braiding model and the LCDM model when n is finite. The theoretical prediction for the large scale structure is confronted with the multipole power spectrum of the luminous red galaxy sample of the Sloan Digital Sky survey. We also discuss future prospects of constraining the kinetic braiding model using a future redshift survey like the WFMOS/SuMIRe PFS survey as well as the cluster redshift distribution in the South Pole Telescope survey.Comment: 41 pages, 20 figures; This version was accepted for publication in JCA

The Formation of Cosmic Structures in a Light Gravitino Dominated Universe

We analyse the formation of cosmic structures in models where the dark matter is dominated by light gravitinos with mass of $100$ eV -- 1 keV, as predicted by gauge-mediated supersymmetry (SUSY) breaking models. After evaluating the number of degrees of freedom at the gravitinos decoupling ($g_*$), we compute the transfer function for matter fluctuations and show that gravitinos behave like warm dark matter (WDM) with free-streaming scale comparable to the galaxy mass scale. We consider different low-density variants of the WDM model, both with and without cosmological constant, and compare the predictions on the abundances of neutral hydrogen within high-redshift damped Ly--$\alpha$ systems and on the number density of local galaxy clusters with the corresponding observational constraints. We find that none of the models satisfies both constraints at the same time, unless a rather small $\Omega_0$ value (\mincir 0.4) and a rather large Hubble parameter (\magcir 0.9) is assumed. Furthermore, in a model with warm + hot dark matter, with hot component provided by massive neutrinos, the strong suppression of fluctuation on scales of \sim 1\hm precludes the formation of high-redshift objects, when the low--$z$ cluster abundance is required. We conclude that all different variants of a light gravitino DM dominated model show strong difficulties for what concerns cosmic structure formation. This gives a severe cosmological constraint on the gauge-mediated SUSY breaking scheme.Comment: 28 pages,Latex, submitted for publication to Phys.Rev.

Galaxy And Mass Assembly (GAMA): testing galaxy formation models through the most massive galaxies in the Universe

We have analysed the growth of Brightest Group Galaxies and Brightest Cluster Galaxies (BGGs/BCGs) over the last 3 billion years using a large sample of 883 galaxies from the Galaxy And Mass Assembly survey. By comparing the stellar mass of BGGs and BCGs in groups and clusters of similar dynamical masses, we find no significant growth between redshift z = 0.27 and 0.09. We also examine the number of BGGs/BCGs that have line emission, finding that approximately 65 per cent of BGGs/BCGs show Hα in emission. From the galaxies where the necessary spectroscopic lines were accurately recovered (54 per cent of the sample), we find that half of this (i.e. 27 per cent of the sample) harbour ongoing star formation with rates up to 10 M⊙ yr−1, and the other half (i.e. 27 per cent of the sample) have an active nucleus (AGN) at the centre. BGGs are more likely to have ongoing star formation, while BCGs show a higher fraction of AGN activity. By examining the position of the BGGs/BCGs with respect to their host dark matter halo, we find that around 13 per cent of them do not lie at the centre of the dark matter halo. This could be an indicator of recent cluster–cluster mergers. We conclude that BGGs and BCGs acquired their stellar mass rapidly at higher redshifts as predicted by semi-analytic models, mildly slowing down at low redshifts

The First Magnetic Fields

We review current ideas on the origin of galactic and extragalactic magnetic fields. We begin by summarizing observations of magnetic fields at cosmological redshifts and on cosmological scales. These observations translate into constraints on the strength and scale magnetic fields must have during the early stages of galaxy formation in order to seed the galactic dynamo. We examine mechanisms for the generation of magnetic fields that operate prior during inflation and during subsequent phase transitions such as electroweak symmetry breaking and the quark-hadron phase transition. The implications of strong primordial magnetic fields for the reionization epoch as well as the first generation of stars is discussed in detail. The exotic, early-Universe mechanisms are contrasted with astrophysical processes that generate fields after recombination. For example, a Biermann-type battery can operate in a proto-galaxy during the early stages of structure formation. Moreover, magnetic fields in either an early generation of stars or active galactic nuclei can be dispersed into the intergalactic medium.Comment: Accepted for publication in Space Science Reviews. Pdf can be also downloaded from http://canopus.cnu.ac.kr/ryu/cosmic-mag1.pd

Effectiveness of EDACS Versus ADAPT Accelerated Diagnostic Pathways for Chest Pain: A Pragmatic Randomized Controlled Trial Embedded Within Practice

Study objective A 2-hour accelerated diagnostic pathway based on the Thrombolysis in Myocardial Infarction score, ECG, and troponin measures (ADAPT-ADP) increased early discharge of patients with suspected acute myocardial infarction presenting to the emergency department compared with standard care (from 11% to 19.3%). Observational studies suggest that an accelerated diagnostic pathway using the Emergency Department Assessment of Chest Pain Score (EDACS-ADP) may further increase this proportion. This trial tests for the existence and size of any beneficial effect of using the EDACS-ADP in routine clinical care. Methods This was a pragmatic randomized controlled trial of adults with suspected acute myocardial infarction, comparing the ADAPT-ADP and the EDACS-ADP. The primary outcome was the proportion of patients discharged to outpatient care within 6 hours of attendance, without subsequent major adverse cardiac event within 30 days. Results Five hundred fifty-eight patients were recruited, 279 in each arm. Sixty-six patients (11.8%) had a major adverse cardiac event within 30 days (ADAPT-ADP 29; EDACS-ADP 37); 11.1% more patients (95% confidence interval 2.8% to 19.4%) were identified as low risk in EDACS-ADP (41.6%) than in ADAPT-ADP (30.5%). No low-risk patients had a major adverse cardiac event within 30 days (0.0% [0.0% to 1.9%]). There was no difference in the primary outcome of proportion discharged within 6 hours (EDACS-ADP 32.3%; ADAPT-ADP 34.4%; difference −2.1% [−10.3% to 6.0%], P=.65). Conclusion There was no difference in the proportion of patients discharged early despite more patients being classified as low risk by the EDACS-ADP than the ADAPT-ADP. Both accelerated diagnostic pathways are effective strategies for chest pain assessment and resulted in an increased rate of early discharges compared with previously reported rates

Isocurvature and Adiabatic Fluctuations of Axion in Chaotic Inflation Models and Large Scale Structure

In the chaotic inflation models, quantum fluctuations for axion fields lead to the overproduction of domain walls and too large isocurvature fluctuations which is inconsistent with the observations of cosmic microwave background anisotropies. These problems are solved by assuming a very flat potential for the Peccei-Quinn scalar. As the simplest possibility, we consider a model where the Peccei-Quinn scalar is an inflaton itself and show that the isocurvature fluctuations can be comparable with the adiabatic ones. We investigate cosmological implications in the case that both adiabatic and isocurvature fluctuations exist and find that the amplitude of the matter spectrum becomes smaller than that for the pure adiabatic case. This leads to relatively high bias parameter ($b \simeq 2$) which is favoured by the current observations.Comment: 5 pages, uudecoded postscript file with figure

Effects on short term outcome of non-invasive ventilation use in the emergency department to treat patients with acute heart failure: A propensity score-based analysis of the EAHFE Registry

Objective: To assess the effects of non-invasive ventilation (NIV) in emergency department (ED) patients with acute heart failure (AHF) on short term outcomes. Methods: Patients from the EAHFE Registry (a multicenter, observational, multipurpose, cohort-designed database including consecutive AHF patients in 41 Spanish EDs) were grouped based on NIV treatment (NIV+ and NIV–groups). Using propensity score (PS) methodology, we identified two subgroups of patients matched by 38 covariates and compared regarding 30-day survival (primary outcome). Interaction was investigated for age, sex, ischemic cardiomyopathy, chronic obstructive pulmonary disease, AHF precipitated by an acute coronary syndrome (ACS), AHF classified as hypertensive or acute pulmonary edema (APE), and systolic blood pressure (SBP). Secondary outcomes were intensive care unit (ICU) admission; mechanical ventilation; in-hospital, 3-day and 7-day mortality; and prolonged hospitalization (>7 days). Results: Of 11, 152 patients from the EAHFE (age (SD): 80 (10) years; 55.5% women), 718 (6.4%) were NIV+ and had a higher 30-day mortality (HR = 2.229; 95%CI = 1.861–2.670) (p 85 years, p < 0.001), AHF associated with ACS (p = 0.045), and SBP < 100 mmHg (p < 0.001). No significant differences were found in the secondary endpoints except for more prolonged hospitalizations in NIV+ patients (OR = 1.445; 95%CI = 1.122–1.862) (p = 0.004). Conclusion: The use of NIV to treat AHF in ED is not associated with improved mortality outcomes and should be cautious in old patients and those with ACS and hypotension

Influence of the length of hospitalisation in post-discharge outcomes in patients with acute heart failure: Results of the LOHRCA study

Objective: To investigate the relationship between length of hospitalisation (LOH) and post-discharge outcomes in acute heart failure (AHF) patients and to ascertain whether there are different patterns according to department of initial hospitalisation. Methods: Consecutive AHF patients hospitalised in 41 Spanish centres were grouped based on the LOH (15 days). Outcomes were defined as 90-day post-discharge all-cause mortality, AHF readmissions, and the combination of both. Hazard ratios (HRs), adjusted by chronic conditions and severity of decompensation, were calculated for groups with LOH >6 days vs. LOH <6 days (reference), and stratified by hospitalisation in cardiology, internal medicine, geriatrics, or short-stay units. Results: We included 8563 patients (mean age: 80 (SD = 10) years, 55.5% women), with a median LOH of 7 days (IQR 4–11): 2934 (34.3%) had a LOH 15 days. The 90-day post-discharge mortality was 11.4%, readmission 32.2%, and combined endpoint 37.4%. Mortality was increased by 36.5% (95%CI = 13.0–64.9) when LOH was 11–15 days, and by 72.0% (95%CI = 42.6–107.5) when >15 days. Conversely, no differences were found in readmission risk, and the combined endpoint only increased 21.6% (95%CI = 8.4–36.4) for LOH >15 days. Stratified analysis by hospitalisation departments rendered similar post-discharge outcomes, with all exhibiting increased mortality for LOH >15 days and no significant increments in readmission risk. Conclusions: Short hospitalisations are not associated with worse outcomes. While post-discharge readmissions are not affected by LOH, mortality risk increases as the LOH lengthens. These findings were similar across hospitalisation departments