Influence of reheating on the trispectrum and its scale dependence

We study the evolution of the non-linear curvature perturbation during perturbative reheating, and hence how observables evolve to their final values which we may compare against observations. Our study includes the evolution of the two trispectrum parameters, \gnl and \taunl, as well as the scale dependence of both \fnl and \taunl. In general the evolution is significant and must be taken into account, which means that models of multifield inflation cannot be compared to observations without specifying how the subsequent reheating takes place. If the trispectrum is large at the end of inflation, it normally remains large at the end of reheating. In the classes of models we study, it is very hard to generate \taunl\gg\fnl^2, regardless of the decay rates of the fields. Similarly, for the classes of models in which \gnl\simeq\taunl during slow--roll inflation, we find the relation typically remains valid during reheating. Therefore it is possible to observationally test such classes of models without specifying the parameters of reheating, even though the individual observables are sensitive to the details of reheating. It is hard to generate an observably large \gnl however. The runnings, \nfnl and \ntaunl, tend to satisfy a consistency relation \ntaunl=(3/2)\nfnl, but are in general too small to be observed for the class of models considered regardless of reheating timescale

Cosmology of Axions and Moduli: A Dynamical Systems Approach

This paper is concerned with string cosmology and the dynamics of multiple scalar fields in potentials that can become negative, and their features as (Early) Dark Energy models. Our point of departure is the "String Axiverse", a scenario that motivates the existence of cosmologically light axion fields as a generic consequence of string theory. We couple such an axion to its corresponding modulus. We give a detailed presentation of the rich cosmology of such a model, ranging from the setting of initial conditions on the fields during inflation, to the asymptotic future. We present some simplifying assumptions based on the fixing of the axion decay constant $f_a$, and on the effective field theory when the modulus trajectory is adiabatic, and find the conditions under which these assumptions break down. As a by-product of our analysis, we find that relaxing the assumption of fixed $f_a$ leads to the appearance of a new meta-stable de-Sitter region for the modulus without the need for uplifting by an additional constant. A dynamical systems analysis reveals the existence of many fixed point attractors, repellers and saddle points, which we analyse in detail. We also provide geometric interpretations of the phase space. The fixed points can be used to bound the couplings in the model. A systematic scan of certain regions of parameter space reveals that the future evolution of the universe in this model can be rich, containing multiple epochs of accelerated expansion.Comment: 27 pages, 12 figures, comments welcome, v2 minor correction

The effectiveness and usability of online, group-based interventions for people with severe obesity: Protocol for a systematic review

\ua9 2021 JMIR Research Protocols. All rights reserved. Background: Globally, obesity is a growing crisis. Despite obesity being preventable, over a quarter of the UK adult population is currently considered clinically obese (typically body mass index ≥35 kg/m2). Access to treatment for people with severe obesity is limited by long wait times and local availability. Online and group-based interventions provide means of increasing the accessibility of obesity prevention and treatment services. However, there has been no prior review of the effectiveness of group-based interventions delivered online for people with severe obesity. Objective: The purpose of this systematic review protocol is to provide an evaluation of the effectiveness and usability of different types of online, group-based interventions for people with severe obesity. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) and the Population, Intervention, Comparator, Outcome, and Study (PICOS) frameworks were used to structure this review. The review will systematically search 7 databases: MEDLINE, Embase, the Cumulative Index of Nursing and Allied Health Literature, APA PsycNet, Web of Science, CENTRAL, and the ProQuest Dissertations and Theses databases. Two authors (MM-I and LB) will independently screen the titles and abstracts of identified articles, select studies for inclusion based on the eligibility criteria, and extract data into a standardized form. Any disagreements will be discussed and resolved by a third reviewer (EM) if necessary. Risk of bias will be assessed using the Cochrane Collaboration Risk of Bias 2 tool and a descriptive analysis will be used to evaluate effectiveness and usability. Results: The systematic review has not yet been started. It is expected to be completed and submitted for publication by December 2021. Conclusions: This systematic review will summarize the effectiveness and usability of online, group-based interventions for people with obesity. It will identify the types of online delivery that have the strongest support to help inform the development of more useful and engaging interventions for people with severe obesity

Doing gender locally: The importance of ‘place’ in understanding marginalised masculinities and young men’s transitions to ‘safe’ and successful futures

Observable anxieties have been developing about the position of boys and young men in contemporary society in recent years. This is expressed as a crisis of masculinity, in which place is often implicitly implicated, but is rarely considered for its role in the shaping of young men’s practices, trajectories and aspirations. Drawing on research conducted with young people who accessed a range of social care support services, this article argues that transition means different things for young men in different locales and that local definitions of masculinity are required to better understand young men’s lives and the opportunities available to them. The authors argue that home life, street life, individual neighbourhoods, regions and nations all shaped the young men’s identities and the practices they (and the staff working with them) drew on in order to create successful futures and ‘safe’ forms of masculinity. It is suggested that this place-based approach has the potential to re-shape the ‘crisis’ discourse surrounding masculinity and the anxieties associated with young men

Nova light curves from the Solar Mass Ejection Imager (SMEI) - II. The extended catalogue

We present the results from observing nine Galactic novae in eruption with the Solar Mass Ejection Imager (SMEI) between 2004 and 2009. While many of these novae reached peak magnitudes that were either at or approaching the detection limits of SMEI, we were still able to produce light curves that in many cases contained more data at and around the initial rise, peak, and decline than those found in other variable star catalogs. For each nova, we obtained a peak time, maximum magnitude, and for several an estimate of the decline time (t2). Interestingly, although of lower quality than those found in Hounsell et al. (2010a), two of the light curves may indicate the presence of a pre-maximum halt. In addition the high cadence of the SMEI instrument has allowed the detection of low amplitude variations in at least one of the nova light curves

Solar-like oscillations in low-luminosity red giants: first results from Kepler

We have measured solar-like oscillations in red giants using time-series photometry from the first 34 days of science operations of the Kepler Mission. The light curves, obtained with 30-minute sampling, reveal clear oscillations in a large sample of G and K giants, extending in luminosity from the red clump down to the bottom of the giant branch. We confirm a strong correlation between the large separation of the oscillations (Delta nu) and the frequency of maximum power (nu_max). We focus on a sample of 50 low-luminosity stars (nu_max > 100 muHz, L <~ 30 L_sun) having high signal-to-noise ratios and showing the unambiguous signature of solar-like oscillations. These are H-shell-burning stars, whose oscillations should be valuable for testing models of stellar evolution and for constraining the star-formation rate in the local disk. We use a new technique to compare stars on a single echelle diagram by scaling their frequencies and find well-defined ridges corresponding to radial and non-radial oscillations, including clear evidence for modes with angular degree l=3. Measuring the small separation between l=0 and l=2 allows us to plot the so-called C-D diagram of delta nu_02 versus Delta nu. The small separation delta nu_01 of l=1 from the midpoint of adjacent l=0 modes is negative, contrary to the Sun and solar-type stars. The ridge for l=1 is notably broadened, which we attribute to mixed modes, confirming theoretical predictions for low-luminosity giants. Overall, the results demonstrate the tremendous potential of Kepler data for asteroseismology of red giants.Comment: accepted by ApJ Letters, to appear in special Kepler issue. Updated reference

Two spatial scales in a bleaching event : corals from the mildest and the most extreme thermal environments escape mortality

Author Posting. © Association for the Sciences of Limnology and Oceanography, 2013. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 58 (2013): 1531-1545, doi:10.4319/lo.2013.58.5.1531.In summer 2010, a bleaching event decimated the abundant reef flat coral Stylophora pistillata in some areas of the central Red Sea, where a series of coral reefs 100–300 m wide by several kilometers long extends from the coastline to about 20 km offshore. Mortality of corals along the exposed and protected sides of inner (inshore) and mid and outer (offshore) reefs and in situ and satellite sea surface temperatures (SSTs) revealed that the variability in the mortality event corresponded to two spatial scales of temperature variability: 300 m across the reef flat and 20 km across a series of reefs. However, the relationship between coral mortality and habitat thermal severity was opposite at the two scales. SSTs in summer 2010 were similar or increased modestly (0.5°C) in the outer and mid reefs relative to 2009. In the inner reef, 2010 temperatures were 1.4°C above the 2009 seasonal maximum for several weeks. We detected little or no coral mortality in mid and outer reefs. In the inner reef, mortality depended on exposure. Within the inner reef, mortality was modest on the protected (shoreward) side, the most severe thermal environment, with highest overall mean and maximum temperatures. In contrast, acute mortality was observed in the exposed (seaward) side, where temperature fluctuations and upper water temperature values were relatively less extreme. Refuges to thermally induced coral bleaching may include sites where extreme, high-frequency thermal variability may select for coral holobionts preadapted to, and physiologically condition corals to withstand, regional increases in water temperature.J.C.B.S. was partially supported by Fundac¸a˜o para a Cieˆncia e a Tecnologia (project PEst-C/MAR/LA0015/2011) and by the European Regional Development Fund through the Operational Competitiveness Programme (National Strategic Reference Framework). Kristen Davis was partially supported by a Woods Hole Oceanographic Institution postdoctoral scholarship. This research was supported by KAUST with awards USA 00002 and KSA 00011

What is the 'problem' that outreach work seeks to address and how might it be tackled? Seeking theory in a primary health prevention programme

&lt;b&gt;Background&lt;/b&gt; Preventive approaches to health are disproportionately accessed by the more affluent and recent health improvement policy advocates the use of targeted preventive primary care to reduce risk factors in poorer individuals and communities. Outreach has become part of the health service response. Outreach has a long history of engaging those who do not otherwise access services. It has, however, been described as eclectic in its purpose, clientele and mode of practice; its effectiveness is unproven. Using a primary prevention programme in the UK as a case, this paper addresses two research questions: what are the perceived problems of non-engagement that outreach aims to address; and, what specific mechanisms of outreach are hypothesised to tackle these.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; Drawing on a wider programme evaluation, the study undertook qualitative interviews with strategically selected health-care professionals. The analysis was thematically guided by the concept of 'candidacy' which theorises the dynamic process through which services and individuals negotiate appropriate service use.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt; The study identified seven types of engagement 'problem' and corresponding solutions. These 'problems' lie on a continuum of complexity in terms of the challenges they present to primary care. Reasons for non-engagement are congruent with the concept of 'candidacy' but point to ways in which it can be expanded.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt; The paper draws conclusions about the role of outreach in contributing to the implementation of inequalities focused primary prevention and identifies further research needed in the theoretical development of both outreach as an approach and candidacy as a conceptual framework