The Complete Star Formation History of the Universe

The determination of the star-formation history of the Universe is a key goal of modern cosmology, as it is crucial to our understanding of how structure in the Universe forms and evolves. A picture has built up over recent years, piece-by-piece, by observing young stars in distant galaxies at different times in the past. These studies indicated that the stellar birthrate peaked some 8 billion years ago, and then declined by a factor of around ten to its present value. Here we report on a new study which obtains the complete star formation history by analysing the fossil record of the stellar populations of 96545 nearby galaxies. Broadly, our results support those derived from high-redshift galaxies elsewhere in the Universe. We find, however, that the peak of star formation was more recent - around 5 billion years ago. Our study also shows that the bigger the stellar mass of the galaxy, the earlier the stars were formed. This striking result indicates a very different formation history for high- and low-mass formation.Comment: Accepted by Nature. Press embargo until publishe

The impact of forearm immobilization and acipimox administration on muscle amino acid metabolism and insulin sensitivity in healthy, young volunteers

This is the author accepted manuscript. The final version is available on open access from the American Physiological Society via the DOI in this recordAlthough the mechanisms underpinning short-term muscle disuse atrophy and associated insulin resistance remain to be elucidated, perturbed lipid metabolism might be involved. Our aim was to determine the impact of acipimox administration (i.e. pharmacologically lowering circulating non-esterified fatty acid (NEFA) availability) on muscle amino acid metabolism and insulin sensitivity during short-term disuse. Eighteen healthy individuals (age 22±1 years, BMI 24.0±0.6 kg·m-2) underwent 2 days forearm immobilization with placebo (PLA; n=9) or acipimox (ACI; 250 mg Olbetam; n=9) ingestion four times daily. Before and after immobilization, whole-body glucose disposal rate (GDR), forearm glucose uptake (FGU, i.e. muscle insulin sensitivity), and amino acid kinetics were measured under fasting and hyperinsulinaemic-hyperaminoacidaemic-euglycaemic clamp conditions using forearm balance and L-[ring-2H5]-phenylalanine infusions. Immobilization did not affect GDR but decreased insulin-stimulated FGU in both groups; more so in ACI (from 53±8 to 12±5 µmol·min-1) than PLA (from 52±8 to 38±13 µmol·min-1; P<0.05). In ACI only, and in contrast to our hypothesis, fasting arterialised NEFA concentrations were elevated to 1.3±0.1 mmol·L-1 post-immobilization (P<0.05), and fasting forearm NEFA balance increased ~4-fold (P=0.10). Forearm phenylalanine net balance decreased following immobilization (P<0.10), driven by increased Ra (from 32±5 (fasting) and 21±4 (clamp) pre-immobilization to 53±8 and 31±4 post-immobilization; P<0.05) while Rd was unaffected by disuse or acipimox. Disuse-induced insulin resistance is accompanied by early signs of negative net muscle amino acid balance, which is driven by accelerated muscle amino acid efflux. Acutely elevated NEFA availability worsened muscle insulin resistance without affecting amino acid kinetics, suggesting increased muscle NEFA uptake may contribute to inactivity-induced insulin resistance but does not cause anabolic resistance.Wellcome TrustNational Institute of Agin

Alcohol Text Messages: A Developmental Study

Risky paternal alcohol use is associated with maternal alcohol use during pregnancy, poor fetal and infant outcomes, domestic violence and depression. This study developed 30 SMS text messages about alcohol for fathers who drink at risky levels. The text messages were developed using two motivational styles: messages presented in a second person voice and the same messages presented in a child’s voice. Fifty-one fathers were recruited through social media to complete an online survey rating the SMS text messages for message importance and likelihood of seeking further information and measuring risky alcohol use and psychosocial distress. Seventeen participants then participated in a semi-structured qualitative interview. Fathers rated the text messages presented in the child’s voice as more important than messages presented in the second person. Qualitative data supported survey results that motivational SMS text messages could provide an acceptable way to raise awareness of risky alcohol consumption for future fathers

Palaeomagnetic field intensity variations suggest Mesoproterozoic inner-core nucleation

The Earth’s inner core grows by the freezing of liquid iron at its surface. The point in history at which this process initiated marks a step-change in the thermal evolution of the planet. Recent computational and experimental studies1,2,3,4,5 have presented radically differing estimates of the thermal conductivity of the Earth’s core, resulting in estimates of the timing of inner-core nucleation ranging from less than half a billion to nearly two billion years ago. Recent inner-core nucleation (high thermal conductivity) requires high outer-core temperatures in the early Earth that complicate models of thermal evolution. The nucleation of the core leads to a different convective regime6 and potentially different magnetic field structures that produce an observable signal in the palaeomagnetic record and allow the date of inner-core nucleation to be estimated directly. Previous studies searching for this signature have been hampered by the paucity of palaeomagnetic intensity measurements, by the lack of an effective means of assessing their reliability, and by shorter-timescale geomagnetic variations. Here we examine results from an expanded Precambrian database of palaeomagnetic intensity measurements7 selected using a new set of reliability criteria8. Our analysis provides intensity-based support for the dominant dipolarity of the time-averaged Precambrian field, a crucial requirement for palaeomagnetic reconstructions of continents. We also present firm evidence for the existence of very long-term variations in geomagnetic strength. The most prominent and robust transition in the record is an increase in both average field strength and variability that is observed to occur between a billion and 1.5 billion years ago. This observation is most readily explained by the nucleation of the inner core occurring during this interval9; the timing would tend to favour a modest value of core thermal conductivity and supports a simple thermal evolution model for the Earth

Focus on vulnerable populations and promoting equity in health service utilization ––an analysis of visitor characteristics and service utilization of the Chinese community health service

Background Community health service in China is designed to provide a convenient and affordable primary health service for the city residents, and to promote health equity. Based on data from a large national study of 35 cities across China, we examined the characteristics of the patients and the utilization of community health institutions (CHIs), and assessed the role of community health service in promoting equity in health service utilization for community residents. Methods Multistage sampling method was applied to select 35 cities in China. Four CHIs were randomly chosen in every district of the 35 cities. A total of 88,482 visitors to the selected CHIs were investigated by using intercept survey method at the exit of the CHIs in 2008, 2009, 2010, and 2011. Descriptive analyses were used to analyze the main characteristics (gender, age, and income) of the CHI visitors, and the results were compared with that from the National Health Services Survey (NHSS, including CHIs and higher levels of hospitals). We also analyzed the service utilization and the satisfactions of the CHI visitors. Results The proportions of the children (2.4%) and the elderly (about 22.7%) were lower in our survey than those in NHSS (9.8% and 38.8% respectively). The proportion of the low-income group (26.4%) was apparently higher than that in NHSS (12.5%). The children group had the lowest satisfaction with the CHIs than other age groups. The satisfaction of the low-income visitors was slightly higher than that of the higher-income visitors. The utilization rate of public health services was low in CHIs. Conclusions The CHIs in China appears to fulfill the public health target of uptake by vulnerable populations, and may play an important role in promoting equity in health service utilization. However, services for children and the elderly should be strengthened

Psychometric properties of the IDS-SR30 for the assessment of depressive symptoms in spanish population

<p>Abstract</p> <p>Background</p> <p>Due to the high prevalence of depression, it is clinically relevant to improve the early identification and assessment of depressive episodes. The main objective of the present study was to examine the psychometric properties of the IDS-SR₃₀(Self-rated Inventory of Depressive Symptomatology) in a large Spanish sample of depressive patients.</p> <p>Methods</p> <p>This prospective, naturalistic, multicenter, nationwide epidemiological study conducted in Spain included 1595 adult patients (65.3% females) with a DSM-IV Major Depressive Disorder (MDD. IDS-SR₃₀and the Hamilton Depression Rating Scale (HDRS, 21 items)were administered to the sample. Data was collected during 2 routine visits. The second assessment was carried out after 10 ± 2 weeks after first assessment.</p> <p>Results</p> <p>The IDS-SR₃₀showed good internal consistency (α = 0.94) and high item total correlations (≥ 0.50) were found in 70% of the items. The convergent validity was 0.85. Results of the principal component analysis (PCA) and confirmatory factor analyses (CFA) showed that a three factor model (labelled mood/cognition, anxiety/somatic and sleep) is adequate for the current sample.</p> <p>Conclusions</p> <p>The Spanish version of the IDS-SR₃₀seems a reliable, valid and useful tool for measuring depression symptomatology in Spanish population.</p

Major impacts of climate change on deep-sea benthic ecosystems

The deep sea encompasses the largest ecosystems on Earth. Although poorly known, deep seafloor ecosystems provide services that are vitally important to the entire ocean and biosphere. Rising atmospheric greenhouse gases are bringing about significant changes in the environmental properties of the ocean realm in terms of water column oxygenation, temperature, pH and food supply, with concomitant impacts on deep-sea ecosystems. Projections suggest that abyssal (3000–6000 m) ocean temperatures could increase by 1°C over the next 84 years, while abyssal seafloor habitats under areas of deep-water formation may experience reductions in water column oxygen concentrations by as much as 0.03 mL L–1 by 2100. Bathyal depths (200–3000 m) worldwide will undergo the most significant reductions in pH in all oceans by the year 2100 (0.29 to 0.37 pH units). O2 concentrations will also decline in the bathyal NE Pacific and Southern Oceans, with losses up to 3.7% or more, especially at intermediate depths. Another important environmental parameter, the flux of particulate organic matter to the seafloor, is likely to decline significantly in most oceans, most notably in the abyssal and bathyal Indian Ocean where it is predicted to decrease by 40–55% by the end of the century. Unfortunately, how these major changes will affect deep-seafloor ecosystems is, in some cases, very poorly understood. In this paper, we provide a detailed overview of the impacts of these changing environmental parameters on deep-seafloor ecosystems that will most likely be seen by 2100 in continental margin, abyssal and polar settings. We also consider how these changes may combine with other anthropogenic stressors (e.g., fishing, mineral mining, oil and gas extraction) to further impact deep-seafloor ecosystems and discuss the possible societal implications

Optical Magnetometry

Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertial-rotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.Comment: 11 pages; 4 figures; submitted to Nature Physic

Neurobehavioral consequences of chronic intrauterine opioid exposure in infants and preschool children: a systematic review and meta-analysis

&lt;b&gt;Background&lt;/b&gt;&lt;p&gt;&lt;/p&gt; It is assumed within the accumulated literature that children born of pregnant opioid dependent mothers have impaired neurobehavioral function as a consequence of chronic intrauterine opioid use.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Quantitative and systematic review of the literature on the consequences of chronic maternal opioid use during pregnancy on neurobehavioral function of children was conducted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched Cinahl, EMBASE, PsychINFO and MEDLINE between the periods of January 1995 to January 2012.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt;&lt;p&gt;&lt;/p&gt; There were only 5 studies out of the 200 identified that quantitatively reported on neurobehavioral function of children after maternal opioid use during pregnancy. All 5 were case control studies with the number of exposed subjects within the studies ranging from 33–143 and 45–85 for the controls. This meta-analysis showed no significant impairments, at a non-conservative significance level of p &#60; 0.05, for cognitive, psychomotor or observed behavioural outcomes for chronic intra-uterine exposed infants and pre-school children compared to non-exposed infants and children. However, all domains suggested a trend to poor outcomes in infants/children of opioid using mothers. The magnitude of all possible effects was small according to Cohen’s benchmark criteria.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Chronic intra-uterine opioid exposed infants and pre-school children experienced no significant impairment in neurobehavioral outcomes when compared to non-exposed peers, although in all domains there was a trend to poorer outcomes. The findings of this review are limited by the small number of studies analysed, the heterogenous populations and small numbers within the individual studies. Longitudinal studies are needed to determine if any neuropsychological impairments appear after the age of 5 years and to help investigate further the role of environmental risk factors on the effect of ‘core’ phenotypes