Curvaton and the inhomogeneous end of inflation

We study the primordial density perturbations and non-Gaussianities generated from the combined effects of an inhomogeneous end of inflation and curvaton decay in hybrid inflation. This dual role is played by a single isocurvature field which is massless during inflation but acquire a mass at the end of inflation via the waterfall phase transition. We calculate the resulting primordial non-Gaussianity characterized by the non-linearity parameter, $f_{NL}$, recovering the usual end-of-inflation result when the field decays promptly and the usual curvaton result if the field decays sufficiently late.Comment: 13 pages, 5 figure

Scale-dependent non-Gaussianity probes inflationary physics

We calculate the scale dependence of the bispectrum and trispectrum in (quasi) local models of non-Gaussian primordial density perturbations, and characterize this scale dependence in terms of new observable parameters. They can help to discriminate between models of inflation, since they are sensitive to properties of the inflationary physics that are not probed by the standard observables. We find consistency relations between these parameters in certain classes of models. We apply our results to a scenario of modulated reheating, showing that the scale dependence of non-Gaussianity can be significant. We also discuss the scale dependence of the bispectrum and trispectrum, in cases where one varies the shape as well as the overall scale of the figure under consideration. We conclude providing a formulation of the curvature perturbation in real space, which generalises the standard local form by dropping the assumption that f_NL and g_NL are constants.Comment: 27 pages, 2 figures. v2: Minor changes to match the published versio

Local Scale-Dependent Non-Gaussian Curvature Perturbations at Cubic Order

We calculate non-Gaussianities in the bispectrum and trispectrum arising from the cubic term in the local expansion of the scalar curvature perturbation. We compute to three-loop order and for general momenta. A procedure for evaluating the leading behavior of the resulting loop-integrals is developed and discussed. Finally, we survey unique non-linear signals which could arise from the cubic term in the squeezed limit. In particular, it is shown that loop corrections can cause $f_{NL}^{sq.}$ to change sign as the momentum scale is varied. There also exists a momentum limit where $\tau_{NL} <0$ can be realized.Comment: Published in JCA

Evolution of fNL to the adiabatic limit

We study inflationary perturbations in multiple-field models, for which zeta typically evolves until all isocurvature modes decay--the "adiabatic limit". We use numerical methods to explore the sensitivity of the nonlinear parameter fNL to the process by which this limit is achieved, finding an appreciable dependence on model-specific data such as the time at which slow-roll breaks down or the timescale of reheating. In models with a sum-separable potential where the isocurvature modes decay before the end of the slow-roll phase we give an analytic criterion for the asymptotic value of fNL to be large. Other examples can be constructed using a waterfall field to terminate inflation while fNL is transiently large, caused by descent from a ridge or convergence into a valley. We show that these two types of evolution are distinguished by the sign of the bispectrum, and give approximate expressions for the peak fNL.Comment: v1: 25 pages, plus Appendix and bibliography, 6 figures. v2: minor edits to match published version in JCA

Pan-European early switch/early discharge opportunities exist for hospitalised patients with methicillin-resistant <em>Staphylococcus</em> <em>aureus</em> complicated skin and soft-tissue infections

AbstractThe objective of this study was to document pan-European real-world treatment patterns and healthcare resource use and estimate opportunities for early switch (ES) from intravenous (IV) to oral antibiotics and early discharge (ED) in hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) complicated skin and soft tissue infections (cSSTIs). This retrospective observational medical chart review study enrolled 342 physicians across 12 European countries who collected data from 1542 patients with documented MRSA cSSTI who were hospitalized (July 2010 to June 2011) and discharged alive (by July 2011). Data included clinical characteristics and outcomes, hospital length of stay (LOS), MRSA-targeted IV and oral antibiotic use, and ES and ED eligibility according to literature-based and expert-validated criteria. The most frequent initial MRSA-active antibiotics were vancomycin (50.2%), linezolid (15.1%), clindamycin (10.8%), and teicoplanin (10.4%). Patients discharged with MRSA-active antibiotics (n = 480) were most frequently prescribed linezolid (42.1%) and clindamycin (19.8%). IV treatment duration (9.3 ± 6.5 vs. 14.6 ± 9.9 days; p <0.001) and hospital LOS (19.1 ± 12.9 vs. 21.0 ± 18.2 days; p 0.162) tended to be shorter for patients switched from IV to oral treatment than for patients who received IV treatment only. Of the patients, 33.6% met ES criteria and could have discontinued IV treatment 6.0 ± 5.5 days earlier, and 37.9% met ED criteria and could have been discharged 6.2 ± 8.2 days earlier. More than one-third of European patients hospitalized for MRSA cSSTI could be eligible for ES and ED, resulting in substantial reductions in IV days and bed-days, with potential savings of €2000 per ED-eligible patient

A comprehensive categorical and bibliometric analysis of published research articles on pediatric pain from 1975-2010

The field of pediatric pain research began in the mid-1970's and has undergone significant growth and development in recent years as evidenced by the variety of books, conferences, and journals on the topic as well as the number of disciplines engaged in work in this area. Using categorical and bibliometric meta-trend analysis, the current study offers a synthesis of research on pediatric pain published between 1975 and 2010 in peer-reviewed journals. Abstracts from 4256 articles, retrieved from Web of Science, were coded across four categories: article type, article topic, type and age of participants, and pain stimulus. The affiliation of the first author and number of citations were also gathered. The results suggest a significant increase in the number of publications over the time period investigated, with 96% of the included articles published since 1990 and most research being multi-authored publications in pain- focused journals. First authors were most often from the United States, and affiliated with a medical department. The majority of studies were original research articles; the most frequent topics were pain characterization (39.86%), pain intervention (37.49%), and pain assessment (25.00%). Clinical samples were most frequent, with participants most often characterized as children (6-12 years) or adolescents (13-18 years) experiencing chronic or acute pain. The findings provide a comprehensive overview of contributions in the field of pediatric pain research over 35 years and offers recommendations for future research in the area. (C) 2015 International Association for the Study of Pai

Nanosized superparamagnetic precipitates in cobalt-doped ZnO

The existence of semiconductors exhibiting long-range ferromagnetic ordering at room temperature still is controversial. One particularly important issue is the presence of secondary magnetic phases such as clusters, segregations, etc... These are often tedious to detect, leading to contradictory interpretations. We show that in our cobalt doped ZnO films grown homoepitaxially on single crystalline ZnO substrates the magnetism unambiguously stems from metallic cobalt nano-inclusions. The magnetic behavior was investigated by SQUID magnetometry, x-ray magnetic circular dichroism, and AC susceptibility measurements. The results were correlated to a detailed microstructural analysis based on high resolution x-ray diffraction, transmission electron microscopy, and electron-spectroscopic imaging. No evidence for carrier mediated ferromagnetic exchange between diluted cobalt moments was found. In contrast, the combined data provide clear evidence that the observed room temperature ferromagnetic-like behavior originates from nanometer sized superparamagnetic metallic cobalt precipitates.Comment: 20 pages, 6 figures; details about background subtraction added to section III. (XMCD

Mapping the Monoceros Ring in 3D with Pan-STARRS1

Using the Pan-STARRS1 survey, we derive limiting magnitude, spatial completeness, and density maps that we use to probe the three-dimensional structure and estimate the stellar mass of the so-called Monoceros Ring. The Monoceros Ring is an enormous and complex stellar sub-structure in the outer Milky Way disk. It is most visible across the large Galactic Anticenter region, $120^\circ \lt l\lt 240^\circ$, $-30^\circ \lt b\lt +40^\circ$. We estimate its stellar mass density profile along every line of sight in 2° × 2° pixels over the entire 30,000 deg2 Pan-STARRS1 survey using the previously developed match software. By parsing this distribution into a radially smooth component and the Monoceros Ring, we obtain its mass and distance from the Sun along each relevant line of sight. The Monoceros Ring is significantly closer to us in the south (6 kpc) than in the north (9 kpc). We also create 2D cross-sections parallel to the Galactic plane that show 135° of the Monoceros Ring in the south and 170° of the Monoceros Ring in the north. We show that the northern and southern structures are also roughly concentric circles, suggesting that they may be waves rippling from a common origin. Excluding the Galactic plane $\sim \pm 4^\circ$, we observe an excess mass of $4\times {10}^{6}{M}_{\odot }$ across $120^\circ \lt l\lt 240^\circ$. If we interpolate across the Galactic plane, we estimate that this region contains $8\times {10}^{6}{M}_{\odot }$. If we assume (somewhat boldly) that the Monoceros Ring is a set of two Galactocentric rings, its total mass is $6\times {10}^{7}{M}_{\odot }$. Finally, if we assume that it is a set of two circles centered at a point 4 kpc from the Galactic center in the anti-central direction, as our data suggests, we estimate its mass to be $4\times {10}^{7}{M}_{\odot }$

Strongly scale-dependent polyspectra from curvaton self-interactions

We study the scale dependence of the non-linearity parameters f_NL and g_NL in curvaton models with self-interactions. We show that the spectral indices n_fNL=d ln|f_NL|/(d ln k) and n_gNL=d ln |g_NL|/(d ln k) can take values much greater than the slow--roll parameters and the spectral index of the power spectrum. This means that the scale--dependence of the bi and trispectrum could be easily observable in this scenario with Planck, which would lead to tight additional constraints on the model. Inspite of the highly non-trivial behaviour of f_NL and g_NL in the curvaton models with self-interactions, we find that the model can be falsified if g_NL(k) is also observed.Comment: 19 pages, many figures. v2: Figure 4 replaced with a corrected normalisation, conclusions unchanged. Matches version published in JCA