The stellar metallicity gradients in galaxy discs in a cosmological scenario

Indexación: Web of ScienceContext. The stellar metallicity gradients of disc galaxies provide information on disc assembly, star formation processes, and chemical evolution. They also might store information on dynamical processes that could affect the distribution of chemical elements in the gas phase and the stellar components. Understanding their joint effects within a hierarchical clustering scenario is of paramount importance. Aims. We studied the stellar metallicity gradients of simulated discs in a cosmological simulation. We explored the dependence of the stellar metallicity gradients on stellar age and on the size and mass of the stellar discs. Methods. We used a catalogue of galaxies with disc components selected from a cosmological hydrodynamical simulation performed including a physically motivated supernova feedback and chemical evolution. Disc components were defined based on angular momentum and binding energy criteria. The metallicity profiles were estimated for stars with different ages. We confront our numerical findings with results from the Calar Alto Legacy Integral Field Area (CALIFA) Survey. Results. The simulated stellar discs are found to have metallicity profiles with slopes in global agreement with observations. Low stellar mass galaxies tend to have a larger variety of metallicity slopes. When normalized by the half-mass radius, the stellar metallicity gradients do not show any dependence and the dispersion increases significantly, regardless of the galaxy mass. Galaxies with stellar masses of around 10(10) M-circle dot show steeper negative metallicity gradients. The stellar metallicity gradients correlate with the half-mass radius. However, the correlation signal is not present when they are normalized by the half-mass radius. Stellar discs with positive age gradients are detected to have negative and positive metallicity gradients, depending on the relative importance of recent star formation activity in the central regions. Conclusions. Our results suggest that inside-out formation is the main process responsible for the metallicity and age profiles. The large dispersions in the metallicity gradients as a function of stellar mass could be ascribed to the effects of dynamical processes such as mergers, interactions and/or migration as well as those regulating the conversion of gas into stars. The fingerprints of the inside-out formation seem better preserved by the stellar metallicity gradients as a function of the half-mass radius.http://www.aanda.org/articles/aa/abs/2016/08/aa28188-16/aa28188-16.htm

Hydrogenase biomimetics: Fe2(CO)4(μ-dppf)(μ-pdt) (dppf = 1,1'-bis(diphenylphosphino)ferrocene) both a proton-reduction and hydrogen oxidation catalyst.

Fe2(CO)4(μ-dppf)(μ-pdt) catalyses the conversion of protons and electrons into hydrogen and also the reverse reaction thus mimicing both types of binuclear hydrogenase enzymes

Poor sleep quality, antepartum depression and suicidal ideation among pregnant women.

To evaluate the independent and combined associations of maternal self-reported poor sleep quality and antepartum depression with suicidal ideation during the third trimester METHODS: A cross-sectional study was conducted among 1298 pregnant women (between 24 and 28 gestational weeks) attending prenatal clinics in Lima, Peru. Antepartum depression and suicidal ideation were assessed using the Patient Health Questionnaire-9 (PHQ-9). The Pittsburgh Sleep Quality Index (PSQI) questionnaire was used to assess sleep quality. Multivariate logistical regression procedures were used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) after adjusting for putative confounders. Approximately, 17% of women were classified as having poor sleep quality (defined using the recommended criteria of PSQI global score of >5 vs. ≤5). Further, the prevalence of antepartum depression and suicidal ideation were 10.3% and 8.5%, respectively in this cohort. After adjusting for confounders including depression, poor sleep quality was associated with a 2.81-fold increased odds of suicidal ideation (OR=2.81; 95% CI 1.78-4.45). When assessed as a continuous variable, each 1-unit increase in the global PSQI score resulted in a 28% increase in odds for suicidal ideation, even after adjusting for depression (OR=1.28; 95% CI 1.15-1.41). The odds of suicidal ideation was particularly high among depressed women with poor sleep quality (OR=13.56 95% CI 7.53-24.41) as compared with women without either risk factor. This cross-sectional study utilized self-reported data. Causality cannot be inferred, and results may not be fully generalizable. Poor sleep quality, even after adjusting for depression, is associated with antepartum suicidal ideation. Our findings support the need to explore sleep-focused interventions for pregnant women

Three-dimensional localization of ultracold atoms in an optical disordered potential

We report a study of three-dimensional (3D) localization of ultracold atoms suspended against gravity, and released in a 3D optical disordered potential with short correlation lengths in all directions. We observe density profiles composed of a steady localized part and a diffusive part. Our observations are compatible with the self-consistent theory of Anderson localization, taking into account the specific features of the experiment, and in particular the broad energy distribution of the atoms placed in the disordered potential. The localization we observe cannot be interpreted as trapping of particles with energy below the classical percolation threshold.Comment: published in Nature Physics; The present version is the initial manuscript (unchanged compared to version 1); The published version is available online at http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2256.htm

Hard X-ray variability of V404 Cygni during the 2015 outburst

Aims. Hard X-ray spectra of black hole binaries (BHB) are produced by Comptonization of soft seed photons by hot electrons near the black hole. The slope of the resulting energy spectra is governed by two main parameters: the electron temperature (T-e) and optical depth () of the emitting plasma. Given the extreme brightness of V404 Cyg during the 2015 outburst, we aim to constrain the source spectral properties using an unprecedented time resolution in hard X-rays, and to monitor the evolution of T-e and tau over the outburst.Methods. We have extracted and analysed 602 X-ray spectra of V404 Cyg obtained by the IBIS / ISGRI instrument on-board INTEGRAL during the 2015 June outburst, using e ff ective integration times ranging between 8 and 176 000 s. We fitted the resulting spectra in the 20-200 keV energy range.Results. We find that while the light curve and soft X-ray spectra of V404 Cyg are remarkably di ff erent from those of other BHBs, the spectral evolution of V404 Cyg in hard X-rays and the relations between the spectral parameters are consistent with those observed in other BHBs. We identify a hard branch in which the T-e is anti-correlated with the hard X-ray flux, and a soft flaring branch in which the relation reverses. In addition, we find that during long X-ray plateaus detected at intermediate fluxes, the thermal Comptonization models fail to describe the spectra. However, the statistics improve if we allow N-H to vary freely in the fits to these spectra.Conclusions. We conclude that the hard branch in V404 Cyg is analogous to the canonical hard state of BHBs. V404 Cyg never seems to enter the canonical soft state, although the soft flaring branch bears resemblance to the BHB intermediate state and ultraluminous state. The X-ray plateaus are likely the result of absorption by a Compton-thick outflow (N-H >= 10(24) cm(2)) which reduces the observed flux by a factor of about 10. Variable covering of the central source by this Compton-thick material may be the reason for the complicated light curve variability, rather than intrinsic source variability

Cohort profile : Oxford Pain, Activity and Lifestyle (OPAL) Study, a prospective cohort study of older adults in England

Purpose: The ‘Oxford Pain, Activity and Lifestyle’ (OPAL) Cohort is a longitudinal, prospective cohort study of adults, aged 65 years and older, living in the community which is investigating the determinants of health in later life. Our focus was on musculoskeletal pain and mobility, but the cohort is designed with flexibility to include new elements over time. This paper describes the study design, data collection and baseline characteristics of participants. We also compared the OPAL baseline characteristics with nationally representative data sources. Participants: We randomly selected eligible participants from two stratified age bands (65–74 and 75 and over years). In total, 5409 individuals (42.1% of eligible participants) from 35 general practices in England agreed to participate between 2016 and 2018. The majority of participants (n=5367) also consented for research team to access their UK National Health Service (NHS) Digital and primary healthcare records. Findings: to date Mean participant age was 74.9 years (range 65–100); 51.5% (n=2784/5409) were women. 94.9% of participants were white, and 28.8% lived alone. Over 83.0% reported pain in at least one body area in the previous 6 weeks. Musculoskeletal symptoms were more prevalent in women (86.4%). One-third of participants reported having one or more falls in the last year. Most participants were confident in their ability to walk outside. The characteristics of OPAL Cohort participants were broadly similar to the general population of the same age. Future plans: Postal follow-up of the cohort is being undertaken at annual intervals, with data collection ongoing. Linkage to NHS hospital admission data is planned. This English prospective cohort offers a large and rich resource for research on the longitudinal associations between demographic, clinical, and social factors and health trajectories and outcomes in community-dwelling older people

Leisure-Time Sedentary Behavior, Alcohol Consumption, and Sexual Intercourse Among Adolescents Aged 12-15 Years in 19 Countries From Africa, the Americas, and Asia

BACKGROUND: The association between sedentary behavior and sexual behavior has not been investigated among adolescents. // AIM: The aim of this study was to: (i) investigate the association between leisure-time sedentary behavior and sexual intercourse, and (ii) test for mediation by alcohol consumption, drug use, physical activity, bullying victimization, parental support/ monitoring, loneliness, and depressive symptoms in a large global sample of young adolescents. // METHODS: Data were analyzed from 34,674 adolescents aged 12-15 years participating in the Global School-based Student Health Survey. Participants reported the number of hours spent in leisure-time sedentary behavior on a typical day (8 hours). Data on alcohol consumption, drug use, physical activity, bullying victimization, parental support/monitoring, loneliness, and depressive symptoms were considered as potential mediators. // OUTCOME: Participants reported whether or not they had sexual intercourse in the past 12 months (yes/no). // RESULTS: The prevalence of past 12-month sexual intercourse was 11.9%, whereas the prevalence of 8 hours per day of leisure-time sedentary behavior were 26.7%, 35.6%, 21.4%, 11.5%, and 4.9%, respectively. There was a dose-dependent relationship between sedentary behavior and odds of reporting sexual intercourse: compared with 8 hours/day of sedentary behavior were 1.12 (0.94-1.33), 1.22 (1.01-1.48), 1.34 (1.08-1.66), and 1.76 (1.37-2.27), respectively. There was no significant interaction by sex. The largest proportion of the association between sedentary behavior and sexual intercourse was explained by alcohol use (% mediated 21.2%), with other factors explaining an additional 11.2%. // CLINICAL TRANSLATION: Interventions to reduce leisure-time sedentary and/or alcohol consumption may contribute to a reduction in the proportion of adolescents engaging in sexual intercourse at a young age. The strengths and limitations of this study are the large, representative sample of adolescents from 19 countries. However, the cross-sectional design means causality or temporal associations could not be established. // CONCLUSIONS: In young adolescents, leisure-time sedentary behavior is positively associated with odds of having sexual intercourse in both boys and girls, in a dose-dependent manner. Alcohol consumption seems to be a key mediator of this relationship

Is Active Transport and Leisure-Time Physical Activity Associated With Inflammatory Markers in US Adults? A Cross-Sectional Analyses From NHANES

Background: To investigate the association between levels of active transport and leisure-time physical activity (LTPA) with C-reactive protein, white blood cell count, body mass index, waist circumference, and lipids in a large representative sample of adults residing in the United States. // Methods: Cross-sectional data from the National Health and Nutrition Examination Survey. Adjusted multinomial logistic regressions were carried out to quantify associations between levels of self-reported active transport (or LTPA) and quintiles of anthropometric measures and serum markers. // Results: A total of 3248 adults were included. For serum inflammatory biomarkers, the authors observed a lower likelihood of being in the top quintile groups of circulating C-reactive protein (adjusted odds ratio [aOR]: 0.60; 95% confidence interval [CI], 0.40–0.90) and white blood cell count (aOR: 0.65; 95% CI, 0.44–0.95) with engaging in low to medium levels of active transport but not with high levels of active transport. Higher levels of LTPA were associated with lower likelihood of having high levels of serum inflammatory biomarkers (aOR: 0.60; 95% CI, 0.42–0.86 in the top C-reactive protein group and aOR: 0.58; 95% CI, 0.39–0.87 in top white blood cell group). // Conclusions: Promoting active transport and/or LTPA may be a beneficial strategy to improving some, but not all, cardiometabolic health outcomes

Congenital Syphilis Presenting with a Generalized Bullous and Pustular Eruption in a Premature Newborn

Congenital syphilis occurs when Treponema pallidum crosses the placenta during pregnancy or from contact with an infectious genital lesion during delivery. Cutaneous manifestations of congenital syphilis are relatively common, occurring in approximately 30% to 70% of patients. Maculopapular lesions, vesiculobullous lesions, condylomata lata lesions, annular lesions, and erythema multiforme-like targetoid lesions have been reported. We report on a premature newborn with congenital syphilis who presented with generalized bullous and pustular eruption and desquamation at birth

Reduction of the ATPase inhibitory factor 1 (IF1) leads to visual impairment in vertebrates

In vertebrates, mitochondria are tightly preserved energy producing organelles, which sustain nervous system development and function. The understanding of proteins that regulate their homoeostasis in complex animals is therefore critical and doing so via means of systemic analysis pivotal to inform pathophysiological conditions associated with mitochondrial deficiency. With the goal to decipher the role of the ATPase inhibitory factor 1 (IF1) in brain development, we employed the zebrafish as elected model reporting that the Atpif1a−/− zebrafish mutant, pinotage (pnttq209), which lacks one of the two IF1 paralogous, exhibits visual impairment alongside increased apoptotic bodies and neuroinflammation in both brain and retina. This associates with increased processing of the dynamin-like GTPase optic atrophy 1 (OPA1), whose ablation is a direct cause of inherited optic atrophy. Defects in vision associated with the processing of OPA1 are specular in Atpif1−/− mice thus confirming a regulatory axis, which interlinks IF1 and OPA1 in the definition of mitochondrial fitness and specialised brain functions. This study unveils a functional relay between IF1 and OPA1 in central nervous system besides representing an example of how the zebrafish model could be harnessed to infer the activity of mitochondrial proteins during development