Dark-Ages Reionisation & Galaxy Formation Simulation XVI: The Thermal Memory of Reionisation

Intergalactic medium temperature is a powerful probe of the epoch of reionisation, as information is retained long after reionisation itself. However, mean temperatures are highly degenerate with the timing of reionisation, with the amount heat injected during the epoch, and with the subsequent cooling rates. We post-process a suite of semi-analytic galaxy formation models to characterise how different thermal statistics of the intergalactic medium can be used to constrain reionisation. Temperature is highly correlated with redshift of reionisation for a period of time after the gas is heated. However as the gas cools, thermal memory of reionisation is lost, and a power-law temperature-density relation is formed, $T = T_0(1+\delta)^{1-\gamma}$ with $\gamma \approx 1.5$. Constraining our model against observations of electron optical depth and temperature at mean density, we find that reionisation likely finished at $z_{\rm{reion}} = 6.8 ^{+ 0.5} _{-0.8}$ with a soft spectral slope of $\alpha = 2.8 ^{+ 1.2} _{-1.0}$. By restricting spectral slope to the range $[0.5,2.5]$ motivated by population II synthesis models, reionisation timing is further constrained to $z_{\rm{reion}} = 6.9 ^{+ 0.4} _{-0.5}$. We find that, in the future, the degeneracies between reionisation timing and background spectrum can be broken using the scatter in temperatures and integrated thermal history.Comment: 17 pages, 17 figures, Accepted for publication in MNRA

Microbial imbalance in inflammatory bowel disease patients at different taxonomic levels

Background Inflammatory bowel disease (IBD), is a debilitating group of chronic diseases including Crohn’s Disease (CD) and ulcerative colitis (UC), which causes inflammation of the gut and affects millions of people worldwide. At different taxonomic levels, the structure of the gut microbiota is significantly altered in IBD patients compared to that of healthy individuals. However, it is unclear how these IBD-affected bacterial groups are related to other common bacteria in the gut, and how they are connected across different disease conditions at the global scale. Results In this study, using faecal samples from patients with IBD, we show through diversity analysis of the microbial community structure based on the 16S rRNA gene that the gut microbiome of IBD patients is less diverse compared to healthy individuals. Furthermore, we have identified which bacterial groups change in abundance in both CD and UC compared to healthy controls. A substantial imbalance was observed across four major bacterial phyla including Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria, which together constitute >98% of the gut microbiota. Next, we reconstructed a bacterial family co-abundance network based on the correlation of abundance profiles obtained from the public gut microbiome data of >22000 samples of faecal and gut biopsies taken from both diseased and healthy individuals. The data was compiled using the EBI metagenomics database [1]. By mapping IBD-altered bacterial families to the network, we show that the bacterial families which exhibit an increased abundance in IBD conditions are not well connected to other groups, implying that these families generally do not coexist together with common gut organisms. Whereas, the bacterial families whose abundance is reduced or did not change in IBD conditions compared to healthy conditions are very well connected to other bacterial groups, suggesting they are highly important groups of bacteria in the gut that can coexist with other bacteria across a range of conditions. Conclusions IBD patients exhibited a less diverse gut microbiome compared to healthy individuals. Bacterial groups which changed in IBD patients were found to be groups which do not co-exist well with common commensal gut bacteria, whereas bacterial groups which did not change in patients with IBD were found to commonly co-exist with commensal gut microbiota. This gives a potential insight into the dynamics of the gut microbiota in patients with IBD

A Complete Spectroscopic Survey of the Milky Way satellite Segue 1: Dark matter content, stellar membership and binary properties from a Bayesian analysis

We introduce a comprehensive analysis of multi-epoch stellar line-of-sight velocities to determine the intrinsic velocity dispersion of the ultrafaint satellites of the Milky Way. Our method includes a simultaneous Bayesian analysis of both membership probabilities and the contribution of binary orbital motion to the observed velocity dispersion within a 14-parameter likelihood. We apply our method to the Segue 1 dwarf galaxy and conclude that Segue 1 is a dark-matter-dominated galaxy at high probability with an intrinsic velocity dispersion of 3.7^{+1.4}_{-1.1} km/sec. The dark matter halo required to produce this dispersion must have an average density of 2.5^{+4.1}_{-1.9} solar mass/pc^3 within a sphere that encloses half the galaxy's stellar luminosity. This is the highest measured density of dark matter in the Local Group. Our results show that a significant fraction of the stars in Segue 1 may be binaries with the most probable mean period close to 10 years, but also consistent with the 180 year mean period seen in the solar vicinity at about 1 sigma. Despite this binary population, the possibility that Segue 1 is a bound star cluster with the observed velocity dispersion arising from the orbital motion of binary stars is disfavored by the multi-epoch stellar velocity data at greater than 99% C.L. Finally, our treatment yields a projected (two-dimensional) half-light radius for the stellar profile of Segue 1 of 28^{+5}_{-4} pc, in excellent agreement with photometric measurements.Comment: 15 pages, 19 figure

Movement patterns of juvenile whale sharks tagged at an aggregation site in the Red Sea

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 9 (2014): e103536, doi:10.1371/journal.pone.0103536.Conservation efforts aimed at the whale shark, Rhincodon typus, remain limited by a lack of basic information on most aspects of its ecology, including global population structure, population sizes and movement patterns. Here we report on the movements of 47 Red Sea whale sharks fitted with three types of satellite transmitting tags from 2009–2011. Most of these sharks were tagged at a single aggregation site near Al-Lith, on the central coast of the Saudi Arabian Red Sea. Individuals encountered at this site were all juveniles based on size estimates ranging from 2.5–7 m total length with a sex ratio of approximately 1:1. All other known aggregation sites for juvenile whale sharks are dominated by males. Results from tagging efforts showed that most individuals remained in the southern Red Sea and that some sharks returned to the same location in subsequent years. Diving data were recorded by 37 tags, revealing frequent deep dives to at least 500 m and as deep as 1360 m. The unique temperature-depth profiles of the Red Sea confirmed that several whale sharks moved out of the Red Sea while tagged. The wide-ranging horizontal movements of these individuals highlight the need for multinational, cooperative efforts to conserve R. typus populations in the Red Sea and Indian Ocean.Financial support was provided in part by KAUST baseline research funds (to MLB), KAUST award nos. USA00002 and KSA 00011 (to SRT), and the United States National Science Foundation (OCE 0825148 to SRT and GBS)

The impact of trauma-center care on mortality and function following pelvic ring and acetabular injuries

ABSTRACT Background: Lower mortality and improved physical function following major polytrauma have been associated with treatment at level-1 trauma centers (TC) compared with that at non-trauma centers (NTC). This study investigates the impact of TC care on outcomes after pelvic and acetabular injuries. Methods: Mortality and quality of life-related measures were compared among patients treated in 18 hospitals with level-1 trauma centers and 51 hospitals without trauma centers in 14 U.S. states. Complete data were obtained on 829 adult trauma patients (18-84 years old) with at least one pelvic ring or acetabular injury (OTA 61 or 62). We used inverse probability of treatment weighting to adjust for observable confounding. Results: After adjustment for case mix, in-hospital mortality was significantly lower at TC versus NTC (RR 0.10, 95% CI 0.02-0.47), as was death by 90 days (RR 0.10, 95% CI 0.02-0.47), and one year (RR 0.21, 95% CI 0.06-0.76) for patients with more severe acetabular injuries (OTA 62-B or 62-C). Patients with combined pelvic ring and acetabular injuries treated at TC had lower mortality by 90 days (RR 0.34, 95% CI 0.14-0.82) and one year (RR 0.30 95% CI 0.14-0.68). Care at TC was also associated with mortality risk reduction for those with unstable pelvic ring injuries (OTA 61-B or 61-C) at one year (RR 0.21, 95%CI 0.06-0.76). Seventy-eight percent of included subjects discharged alive was available for interview at twelve months. Average absolute differences in SF-36 physical functioning and Musculoskeletal Functional Assessment at one year were 11.4 (95%CI 5.3 – 17.4) and 13.2 (1.7 – 24.7) respectively, indicating statistically and clinically significant improved outcomes with TC treatment for more severe acetabular injuries. Conclusions: Mortality is reduced for patients with unstable pelvic and severe acetabular injuries when care is provided in a TC compared to NTC. Moreover, those with severe acetabular fractures experience improved physical function at one year. Patients with these injuries represent a well-defined subset of trauma patients that should be preferentially triaged or transferred to a Level-1 trauma center

Using the Patient Health Questionnaire (PHQ-9) and the Edinburgh Postnatal Depression Scale (EPDS) to assess suicidal ideation among pregnant women in Lima, Peru.

We sought to examine the concordance of two suicidal ideation items from the Patient Health Questionnaire-9 (PHQ-9) and the Edinburgh Postnatal Depression Scale (EPDS), to evaluate the prevalence of suicidal ideation among pregnant women, and to assess the co-occurrence of suicidal ideation with antepartum depressive symptoms. A cross-sectional study was conducted among 1,517 pregnant women attending prenatal care clinics in Lima, Peru. Item 9 of the PHQ-9 assesses suicidal ideation over the last 14 days while item 10 of the EPDS assesses suicidal ideation in the past 7 days. The two suicidal ideation items have a high concordance rate (84.2 %) but a moderate agreement (the Cohen's kappa = 0.42). Based on the PHQ-9 and the EPDS, 15.8 and 8.8 % of participants screened positive for suicidal ideation, respectively. Assessed by the PHQ-9, 51 % of participants with suicidal ideation had probable depression. In prenatal care clinics, screening for suicidal ideation is needed for women with and without depressive symptoms. Future studies are needed to identify additional predictors of antepartum suicidality, determine the appropriate duration of reporting period for suicidal ideation screening, and assess the percentage of individuals with positive responses to the two suicidal ideation items at high risk of planning and attempting suicide.This research was supported by an award from the National Institutes of Health (NIH), the Eunice Kennedy Shriver Institute of Child Health and Human Development (R01-HD-059835). The NIH had no further role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication. The authors wish to thank the dedicated staff members of Asociacion Civil Proyectos en Salud (PROESA), Peru and Instituto Especializado Materno Perinatal, Peru for their expert technical assistance with this research. The authors would like to thank Kathy Brenner for her help with revising this manuscript.Revisión por pare

Supersymmetric Godel-type Universe in four Dimensions

We generalize the classification of all supersymmetric solutions of pure N=2, D=4 gauged supergravity to the case when external sources are included. It is shown that the source must be an electrically charged dust. We give a particular solution to the resulting equations, that describes a Goedel-type universe preserving one quarter of the supersymmetries.Comment: 6 pages, Latex. v2: references and footnote added. v3: introduction expanded, minor corrections, references added. Final versio

VCU... Making Richmond A Great Place to Work and Live

VCU, established in 1968, is a young, vibrant and rapidly growing institution. Whereas components of VCU are well established, venerable, and well-recognized institutions, VCU suffers from a lack of name recognition and reputation in comparison with our peer institutions. Similarly, there is a general lack of appreciation for the strength of VCU programs at the regional, local and even institutional level. This project is designed to showcase, at the local and institutional level, the special contributions and triumphs of VCU and its staff, including both the cutting edge research and academic accomplishments and the powerful and compelling human interest stories that contribute to the richness and vitality of our institution. Our venue will be the offering of vignettes highlighting these stories on local radio, television or other media outlets. Our vision for the project is to provide a vehicle by which we promote a sense of pride in our campus communities, as well as promote the success of VCU in the Greater Richmond Area and throughout the Commonwealth. Appreciation of the strengths and successes of the institution will enhance morale of faculty and staff, positively affect students, staff and faculty recruitment and retention, and help to maintain VCU as a Research Extensive academic institution