350 research outputs found
Sulfur isotopes of hydrothermal vent fossils and insights into microbial sulfur cycling within a lower Paleozoic (Ordovicianâearly Silurian) vent community
This study was supported by a UK Natural Environment Research Council grant (NERC; number NE/R000670/1 to AG). MG is also grateful for support from an Ifremer Postdoctoral Fellowship. Alvinella samples were collected with the help of a NERC Small Grant (number NE/C000714/1 to CTSL). S isotopic analyses were undertaken under NERC Facility awards IP-1755-1117 and IMF672/1118.Symbioses between metazoans and microbes involved in sulfur cycling are integral to the ability of animals to thrive within deepâsea hydrothermal vent environments; the development of such interactions is regarded as a key adaptation in enabling animals to successfully colonize vents. Microbes often colonize the surfaces of vent animals and, remarkably, these associations can also be observed intricately preserved by pyrite in the fossil record of vent environments, stretching back to the lower Paleozoic (Ordovicianâearly Silurian). In nonâvent environments, sulfur isotopes are often employed to investigate the metabolic strategies of both modern and fossil organisms, as certain metabolic pathways of microbes, notably sulfate reduction, can produce large sulfur isotope fractionations. However, the sulfur isotopes of vent fossils, both ancient and recently mineralized, have seldom been explored, and it is not known if the pyriteâpreserved vent organisms might also preserve potential signatures of their metabolisms. Here, we use highâresolution secondary ion mass spectrometry (SIMS) to investigate the sulfur isotopes of pyrites from recently mineralized and Ordovicianâearly Silurian tubeworm fossils with associated microbial fossils. Our results demonstrate that pyrites containing microbial fossils consistently have significantly more negative δ34S values compared with nearby nonâfossiliferous pyrites, and thus represent the first indication that the presence of microbial sulfurâcycling communities active at the time of pyrite formation influenced the sulfur isotope signatures of pyrite at hydrothermal vents. The observed depletions in δ34S are generally small in magnitude and are perhaps best explained by sulfur isotope fractionation through a combination of sulfurâcycling processes carried out by vent microbes. These results highlight the potential for using sulfur isotopes to explore biological functional relationships within fossil vent communities, and to enhance understanding of how microbial and animal life has coâevolved to colonize vents throughout geological time.Publisher PDFPeer reviewe
Long-term effect of weight regain following behavioral weight management programs on cardiometabolic disease incidence and risk: systematic review and meta-analysis
Background:Â Behavioral weight management programs (BWMPs) enhance weight loss in the short term, but longer term cardiometabolic effects are uncertain as weight is commonly regained. We assessed the impact of weight regain after BWMPs on cardiovascular risk factors, diabetes, and cardiovascular disease.
Methods: Trial registries, 11 databases, and forward-citation searching (latest search, December 19) were used to identify articles published in English, from any geographical region. Randomized trials of BWMPs in adults with overweight/obesity reporting cardiometabolic outcomes at âĽ12 months at and after program end were included. Differences between more intensive interventions and comparator groups were synthesized using mixed-effects, meta-regression, and time-to-event models to assess the impact of weight regain on cardiovascular disease incidence and risk.
Results: One hundred twenty-four trials reporting on âĽ1 cardiometabolic outcomes with a median follow-up of 28 (range, 11â360) months after program end were included. Median baseline participant body mass index was 33 kg/m2; median age was 51 years. Eight and 15 study arms (7889 and 4202 participants, respectively) examined the incidence of cardiovascular disease and type 2 diabetes, respectively, with imprecise evidence of a lower incidence for at least 5 years. Weight regain in BWMPs relative to comparators reduced these differences. One and 5 years after program end, total cholesterol/HDL (high-density lipoprotein) ratio was 1.5 points lower at both times (82 studies; 19â003 participants), systolic blood pressure was 1.5 mm mercury and 0.4 mm lower (84 studies; 30â836 participants), and HbA1c (%) 0.38 lower at both times (94 studies; 28â083 participants). Of the included studies, 22% were judged at high risk of bias; removing these did not meaningfully change results.
Conclusions: Despite weight regain, BWMPs reduce cardiometabolic risk factors with effects lasting at least 5 years after program end and dwindling with weight regain. Evidence that they reduce the incidence of cardiovascular disease or diabetes is less certain. Few studies followed participants for âĽ5 years.
Registration:Â URL:Â https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42018105744
Are people who participate in cultural activities more satisfied with life?
The influence of various aspects of life on wellbeing has been extensively researched. However, despite little empirical evidence, participation in leisure activities has been assumed to increase subjective wellbeing. Leisure is important because it is more under personal control than other sources of life satisfaction. This study asked whether people who participate in cultural leisure activities have higher life satisfaction than people who do not, if different types of leisure have the same influence on life satisfaction and if satisfaction is dependent on the frequency of participation or the number of activities undertaken. It used data from UKHLS Survey to establish associations between type, number and frequency of participation in leisure activities and life satisfaction. Results showed an independent and positive association of participation in sport, heritage and active-creative leisure activities and life satisfaction but not for participation in popular entertainment, theatre hobbies and museum/galleries. The association of reading hobbies and sedentary-creative activities and life satisfaction was negative. High life satisfaction was associated with engaging in a number of different activities rather than the frequency of participation in each of them. The results have implications for policy makers and leisure services providers, in particular those associated with heritage recreation. Subjective wellbeing measures, such as life satisfaction, and not economic measures alone should be considered in the evaluation of services. The promotion of leisure activities which are active and promote social interaction should be considered in programmes aimed at improving the quality of life
Design and On-Orbit Operation of the Adiabatic Demagnetization Refrigerator on the Hitomi Soft X-Ray Spectrometer Instrument
The Soft X-ray Spectrometer instrument on the Astro-H observatory contains a 6x6 array of x-ray microcalorimeters that is cooled to 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consists of three stages in order to provide stable detector cooling using either a 1.2 K superfluid helium bath or a 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. When liquid helium is present, two of the ADR's stages are used to single-shot cool the detectors while rejecting heat to the helium. After the helium is depleted, all three stages are used to continuously cool the helium tank (to about 1.5 K) and single-shot cool the detectors (to 50 mK), using the JT cryocooler as its heat sink. The Astro-H observatory, renamed Hitomi after its successful launch in February 2016, carried approximately 36 liters of helium into orbit. On day 5, the helium had cooled sufficiently (<1.4 K) to allow operation of the ADR. This paper describes the design, operation and on-orbit performance of the ADR, and the use of the ADR's heat rejection as a tool for mass gauging the helium tank
Mechanisms of Psychological Distress following War in the Former Yugoslavia: The Role of Interpersonal Sensitivity
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This study was funded by a grant from the European Commission, contract number INCO-CT-2004-509176. AN was supported by a Clinical Early Career Research Fellowship (113295) and a Project Grant (104288
Relationships within the Araceae: comparison of morphological patterns with molecular phylogenies.
Premise of the study: The first family-wide molecular phylogeny of the Araceae, a family of about 3800 published species in 120 genera, became available in 1995, followed by a cladistic analysis of morpho-anatomical data in 1997. The most recent and comprehensive family-wide molecular phylogeny was published in 2008 and included species from 102 genera. We reanalyzed the molecular data with a more complete genus sampling and compared the resulting phylogeny with morphological and anatomical data, with a view to contributing to a new formal classification of the Araceae.
⢠Methods: We analyzed 113 aroid genera and 4494 aligned nucleotides that resulted from adding 11 genera to the 2008 molecular matrix. We also analyzed 81 morphological characters in the context of the molecular phylogeny, using an extended version of the 1997 morpho-anatomical data set.
⢠Key results: The resulting maximum-likelihood phylogeny is well resolved and supported, and most of the 44 larger clades also have morphological or anatomical synapomorphies as well as ecological or geographic cohesion. Of the 44 clades, 16 are here newly circumscribed and informally named. However, some relationships remain poorly supported within the Aroideae subfamily. The most problematic placement is Calla within Aroideae, which conflicts with the distribution of morphological, anatomical, and palynological character states.
⢠Conclusions: The comparison of the molecular analysis with morphological and anatomical data presented here represents an important basis for a new formal classification for the Araceae and for the understanding of the evolution of this ancient family, a monocot group known in the fossil record from the early Cretaceous
A Unique Population of Ventral Tegmental Area Neurons Inhibits the Lateral Habenula to Promote Reward
Lateral habenula (LHb) neurons convey aversive and negative reward conditions through potent indirect inhibition of ventral tegmental area (VTA) dopaminergic neurons. While VTA dopaminergic neurons reciprocally project to the LHb, the electrophysiological properties and the behavioral consequences associated with selective manipulations of this circuit are unknown. Here, we identify a novel inhibitory input to the LHb arising from a unique population of VTA neurons expressing dopaminergic markers. Optogenetic activation of this circuit resulted in no detectable dopamine release in LHb brain slices. Instead, stimulation produced GABA-mediated inhibitory synaptic transmission, which suppressed the firing of postsynaptic LHb neurons in brain slices and increased the spontaneous firing rate of VTA dopaminergic neurons in vivo. Furthermore, in vivo activation of this pathway produced reward-related phenotypes that were dependent on intra-LHb GABAA receptor signaling. These results suggest that non-canonical inhibitory signaling by these hybrid dopaminergic-GABAergic neurons act to suppress LHb output under rewarding conditions
The Astropy Problem
The Astropy Project (http://astropy.org) is, in its own words, "a community
effort to develop a single core package for Astronomy in Python and foster
interoperability between Python astronomy packages." For five years this
project has been managed, written, and operated as a grassroots,
self-organized, almost entirely volunteer effort while the software is used by
the majority of the astronomical community. Despite this, the project has
always been and remains to this day effectively unfunded. Further, contributors
receive little or no formal recognition for creating and supporting what is now
critical software. This paper explores the problem in detail, outlines possible
solutions to correct this, and presents a few suggestions on how to address the
sustainability of general purpose astronomical software
Association between characteristics of behavioural weight loss programmes and weight change after programme end: systematic review and meta-analysis
Objective: To determine if the characteristics of behavioural weight loss programmes influence the rate of change in weight after the end of the programme.Design: Systematic review and meta-analysis.Data sources: Trial registries, 11 electronic databases, and forward citation searching (from database inception; latest search December 2019). Randomised trials of behavioural weight loss programmes in adults with overweight or obesity, reporting outcomes at âĽ12 months, including at the end of the programme and after the end of the programme.Review methods: Studies were screened by two independent reviewers with discrepancies resolved by discussion. 5% of the studies identified in the searches met the inclusion criteria. One reviewer extracted the data and a second reviewer checked the data. Risk of bias was assessed with Cochraneâs risk of bias tool (version 1). The rate of change in weight was calculated (kg/month; converted to kg/year for interpretability) after the end of the programme in the intervention versus control groups by a mixed model with a random intercept. Associations between the rate of change in weight and prespecified variables were tested.Results: Data were analysed from 249 trials (n=59â081) with a mean length of follow-up of two years (longest 30 years). 56% of studies (n=140) had an unclear risk of bias, 21% (n=52) a low risk, and 23% (n=57) a high risk of bias. Regain in weight was faster in the intervention versus the no intervention control groups (0.12-0.32 kg/year) but the difference between groups was maintained for at least five years. Each kilogram of weight lost at the end of the programme was associated with faster regain in weight at a rate of 0.13-0.19 kg/year. Financial incentives for weight loss were associated with faster regain in weight at a rate of 1-1.5 kg/year. Compared with programmes with no meal replacements, interventions involving partial meal replacements were associated with faster regain in weight but not after adjustment for weight loss during the programme. Access to the programme outside of the study was associated with slower regain in weight. Programmes where the intensity of the interaction reduced gradually were also associated with slower regain in weight in the multivariable analysis, although the point estimate suggested that the association was small. Other characteristics did not explain the heterogeneity in regain in weight.Conclusion: Faster regain in weight after weight loss was associated with greater initial weight loss, but greater initial weight loss was still associated with reduced weight for at least five years after the end of the programme, after which data were limited. Continued availability of the programme to participants outside of the study predicted a slower regain in weight, and provision of financial incentives predicted faster regain in weight; no other clear associations were found
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