2,267 research outputs found

    IN-SYNC. V. Stellar kinematics and dynamics in the Orion A Molecular Cloud

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    The kinematics and dynamics of young stellar populations enable us to test theories of star formation. With this aim, we continue our analysis of the SDSS-III/APOGEE IN-SYNC survey, a high resolution near infrared spectroscopic survey of young clusters. We focus on the Orion A star-forming region, for which IN-SYNC obtained spectra of 2700\sim2700 stars. In Paper IV we used these data to study the young stellar population. Here we study the kinematic properties through radial velocities (vrv_r). The young stellar population remains kinematically associated with the molecular gas, following a 10kms1\sim10\:{\rm{km\:s}}^{-1} gradient along filament. However, near the center of the region, the vrv_r distribution is slightly blueshifted and asymmetric; we suggest that this population, which is older, is slightly in foreground. We find evidence for kinematic subclustering, detecting statistically significant groupings of co-located stars with coherent motions. These are mostly in the lower-density regions of the cloud, while the ONC radial velocities are smoothly distributed, consistent with it being an older, more dynamically evolved cluster. The velocity dispersion σv\sigma_v varies along the filament. The ONC appears virialized, or just slightly supervirial, consistent with an old dynamical age. Here there is also some evidence for on-going expansion, from a vrv_r--extinction correlation. In the southern filament, σv\sigma_v is 2\sim2--33 times larger than virial in the L1641N region, where we infer a superposition along the line of sight of stellar sub-populations, detached from the gas. On the contrary, σv\sigma_v decreases towards L1641S, where the population is again in agreement with a virial state.Comment: 14 pages, 13 figures, ApJ accepte

    Gut microbiome and antibiotic resistance effects during travelers\u27 diarrhea treatment and prevention

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    The travelers\u27 gut microbiome is potentially assaulted by acute and chronic perturbations (e.g., diarrhea, antibiotic use, and different environments). Prior studies of the impact of travel and travelers\u27 diarrhea (TD) on the microbiome have not directly compared antibiotic regimens, and studies of different antibiotic regimens have not considered travelers\u27 microbiomes. This gap is important to be addressed as the use of antibiotics to treat or prevent TD-even in moderate to severe cases or in regions with high infectious disease burden-is controversial based on the concerns for unintended consequences to the gut microbiome and antimicrobial resistance (AMR) emergence. Our study addresses this by evaluating the impact of defined antibiotic regimens (single-dose treatment or daily prophylaxis) on the gut microbiome and resistomes of deployed servicemembers, using samples collected during clinical trials. Our findings indicate that the antibiotic treatment regimens that were studied generally do not lead to adverse effects on the gut microbiome and resistome and identify the relative risks associated with prophylaxis. These results can be used to inform therapeutic guidelines for the prevention and treatment of TD and make progress toward using microbiome information in personalized medical care

    Serverification of Molecular Modeling Applications: the Rosetta Online Server that Includes Everyone (ROSIE)

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    The Rosetta molecular modeling software package provides experimentally tested and rapidly evolving tools for the 3D structure prediction and high-resolution design of proteins, nucleic acids, and a growing number of non-natural polymers. Despite its free availability to academic users and improving documentation, use of Rosetta has largely remained confined to developers and their immediate collaborators due to the code's difficulty of use, the requirement for large computational resources, and the unavailability of servers for most of the Rosetta applications. Here, we present a unified web framework for Rosetta applications called ROSIE (Rosetta Online Server that Includes Everyone). ROSIE provides (a) a common user interface for Rosetta protocols, (b) a stable application programming interface for developers to add additional protocols, (c) a flexible back-end to allow leveraging of computer cluster resources shared by RosettaCommons member institutions, and (d) centralized administration by the RosettaCommons to ensure continuous maintenance. This paper describes the ROSIE server infrastructure, a step-by-step 'serverification' protocol for use by Rosetta developers, and the deployment of the first nine ROSIE applications by six separate developer teams: Docking, RNA de novo, ERRASER, Antibody, Sequence Tolerance, Supercharge, Beta peptide design, NCBB design, and VIP redesign. As illustrated by the number and diversity of these applications, ROSIE offers a general and speedy paradigm for serverification of Rosetta applications that incurs negligible cost to developers and lowers barriers to Rosetta use for the broader biological community. ROSIE is available at http://rosie.rosettacommons.org

    Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock

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    Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations

    A qualitative study of the experiences of individuals who did not complete the NHS Low Calorie Diet Programme Pilot

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    Background: Attrition remains a significant public health challenge as individuals who do not complete programmes are likely to have poorer programme outcomes. On calorie- restricted diets, including the NHS Low Calorie Diet (LCD) Programme pilot, approximately 50% of people are discharged prematurely, and thus do not complete the programme. Reducing attrition therefore has the potential to improve programme efficacy, impact and cost-effectiveness. Methods: Ten semi-structured interviews were conducted with purposively sampled individuals who did not complete the NHS LCD programme. Interviews explored service user experiences of the programme and experiences of being discharged. Interview data were analysed thematically. Results: Four core themes were identified: 1) the pre- programme struggles of service users and their route to LCD; 2) a positive and impactful programme; 3) life gets in the way; and 4) a perceived lack of support from the provider. These findings show that individuals had pre-programme struggles and a series of life events that constrained their good intentions, and whilst they were positive about the programme, they were critical of the support they received from providers to deal with their life circumstances. Conclusions: Policy makers and providers can act proportionately to ensure that programmes, such as the NHS LCD Programme pilot, recognise the circumstances and context of people’s lives, and take a more person-centred approach
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