418 research outputs found
Tissue-specific regulation of sirtuin and nicotinamide adenine dinucleotide biosynthetic pathways identified in C57Bl/6 mice in response to high-fat feeding
Funding: The Scottish Government's Rural and Environment Science and Analytical Services Division.Peer reviewedPostprin
Measuring Galaxy Star Formation Rates From Integrated Photometry: Insights from Color-Magnitude Diagrams of Resolved Stars
We use empirical star formation histories (SFHs), measured from HST-based
resolved star color-magnitude diagrams, as input into population synthesis
codes to model the broadband spectral energy distributions (SEDs) of ~50 nearby
dwarf galaxies (6.5 < log M/M_* < 8.5, with metallicities ~10% solar). In the
presence of realistic SFHs, we compare the modeled and observed SEDs from the
ultraviolet (UV) through near-infrared (NIR) and assess the reliability of
widely used UV-based star formation rate (SFR) indicators. In the FUV through i
bands, we find that the observed and modeled SEDs are in excellent agreement.
In the Spitzer 3.6micron and 4.5micron bands, we find that modeled SEDs
systematically over-predict observed luminosities by up to ~0.2 dex, depending
on treatment of the TP-AGB stars in the synthesis models. We assess the
reliability of UV luminosity as a SFR indicator, in light of independently
constrained SFHs. We find that fluctuations in the SFHs alone can cause factor
of ~2 variations in the UV luminosities relative to the assumption of a
constant SFH over the past 100 Myr. These variations are not strongly
correlated with UV-optical colors, implying that correcting UV-based SFRs for
the effects of realistic SFHs is difficult using only the broadband SED.
Additionally, for this diverse sample of galaxies, we find that stars older
than 100 Myr can contribute from <5% to100% of the present day UV luminosity,
highlighting the challenges in defining a characteristic star formation
timescale associated with UV emission. We do find a relationship between UV
emission timescale and broadband UV-optical color, though it is different than
predictions based on exponentially declining SFH models. Our findings have
significant implications for the comparison of UV-based SFRs across
low-metallicity populations with diverse SFHs.Comment: 22 pages, 15 figures, ApJ accepte
Association between exposure to combat-related stress and psychological health in aging men: The Atherosclerosis Risk in Communities (ARIC) Study
Exposure to military combat has been associated with myriad adverse health effects. The mechanisms linking these two events are not well understood but may include negative emotional states, such as anger and vital exhaustion. We investigated the relationship between combat status and psychological functioning (trait anger and vital exhaustion) among middle-aged men (N=5,347) who participated in the Life Course Socioeconomic Status, Social Context and Cardiovascular Disease Study, an ancillary study to the Atherosclerosis Risk in Communities (ARIC) Study. Combat status was significantly associated with trait anger, although results were limited to men (combat veterans compared to non-combat veterans and combat and non-combat veterans compared to non-veterans) of the Korean and Vietnam War eras. Non-combat veterans from the World War II and Vietnam War eras reported lower vital exhaustion compared to non-veterans. Combat status is significantly associated with trait anger among men of the Korean and Vietnam War eras. Anger proneness may be a mechanism through which combat stress is associated with adverse health outcomes
Protocol for Monitoring Aquatic Invertebrates of Small Streams in the Heartland Inventory & Monitoring Network, Version 2.1
Executive Summary
The Heartland Inventory and Monitoring Network (HTLN) is a component of the National Park Serviceās (NPS) strategy to improve park management through greater reliance on scientific information. The purposes of this program are to design and implement long-term ecological monitoring and provide information for park managers to evaluate the integrity of park ecosystems and better understand ecosystem processes. Concerns over declining surface water quality have led to the development of various monitoring approaches to assess stream water quality. Freshwater streams in network parks are threatened by numerous stressors, most of which originate outside park boundaries. Stream condition and ecosystem health are dependent on processes occurring in the entire watershed as well as riparian and floodplain areas; therefore, they cannot be manipulated independently of this interrelationship. Land use activitiesāsuch as timber management, landfills, grazing, confined animal feeding operations, urbanization, stream channelization, removal of riparian vegetation and gravel, and mineral and metals miningāthreaten stream quality. Accordingly, the framework for this aquatic monitoring is directed towards maintaining the ecological integrity of the streams in those parks.
Invertebrates are an important tool for understanding and detecting changes in ecosystem integrity, and they can be used to reflect cumulative impacts that cannot otherwise be detected through traditional water quality monitoring. The broad diversity of invertebrate species occurring in aquatic systems similarly demonstrates a broad range of responses to different environmental stressors. Benthic invertebrates are sensitive to the wide variety of impacts that influence Ozark streams. Benthic invertebrate community structure can be quantified to reflect stream integrity in several ways, including the absence of pollution sensitive taxa, dominance by a particular taxon combined with low overall taxa richness, or appreciable shifts in community composition relative to reference condition. Furthermore, changes in the diversity and community structure of benthic invertebrates are relatively simple to communicate to resource managers and the public. To assess the natural and anthropogenic processes influencing invertebrate communities, this protocol has been designed to incorporate the spatial relationship of benthic invertebrates with their local habitat including substrate size and embeddedness, and water quality parameters (temperature, dissolved oxygen, pH, specific conductance, and turbidity). Rigid quality control and quality assurance are used to ensure maximum data integrity. Detailed standard operating procedures (SOPs) and supporting information are associated with this protocol
Protocol for Monitoring Fish Communities in Small Streams in the Heartland Inventory and Monitoring Network, Version 2.0
Executive Summary
Fish communities are an important component of aquatic systems and are good bioindicators of ecosystem health. Land use changes in the Midwest have caused sedimentation, erosion, and nutrient loading that degrades and fragments habitat and impairs water quality. Because most small wadeable streams in the Heartland Inventory and Monitoring Network (HTLN) have a relatively small area of their watersheds located within park boundaries, these streams are at risk of degradation due to adjacent land use practices and other anthropogenic disturbances. Shifts in the physical and chemical properties of aquatic systems have a dramatic effect on the biotic community. The federally endangered Topeka shiner (Notropis topeka) and other native fishes have declined in population size due to habitat degradation and fragmentation in Midwest streams. By protecting portions of streams on publicly owned lands, national parks may offer refuges for threatened or endangered species and species of conservation concern, as well as other native species.
This protocol describes the background, history, justification, methodology, data analysis and data management for long-term fish community monitoring of wadeable streams within nine HTLN parks: Effigy Mounds National Monument (EFMO), George Washington Carver National Monument (GWCA), Herbert Hoover National Historic Site (HEHO), Homestead National Monument of America (HOME), Hot Springs National Park (HOSP), Pea Ridge National Military Park (PERI), Pipestone National Monument (PIPE), Tallgrass Prairie National Preserve (TAPR), and Wilson\u27s Creek National Battlefield (WICR). The objectives of this protocol are to determine the status and long-term trends in fish richness, diversity, abundance, and community composition in small wadeable streams within these nine parks and correlate the long-term community data to overall water quality and habitat condition (DeBacker et al. 2005)
Dietary fibers inhibit obesity in mice, but host responses in the cecum and liver appear unrelated to fiber-specific changes in cecal bacterial taxonomic composition
Peer reviewedPublisher PD
Vital Exhaustion as a Risk Factor for Adverse Cardiac Events (from the Atherosclerosis Risk In Communities [ARIC] Study)
Vital exhaustion, defined as excessive fatigue, feelings of demoralization, and increased irritability, has been identified as a risk factor for incident and recurrent cardiac events, but there are no prospective studies of this association in United States samples. We examined the predictive value of vital exhaustion for incident myocardial infarction or fatal coronary heart disease (CHD) among middle-aged men and women in four US communities. Participants were 12,895 black or white men and women enrolled in the Atherosclerosis Risk In Communities (ARIC) Study cohort and followed for the occurrence of cardiac morbidity and mortality from 1990 through 2002 (maximum follow-up = 13.0 years). Vital exhaustion was assessed using the 21-item Maastricht Questionnaire, and partitioned into approximate quartiles for statistical analyses. High vital exhaustion (the fourth quartile) predicted adverse cardiac events in age-, gender-, and race-center-adjusted analyses (1.69 [95% C.I: 1.40 to 2.05]) and in analyses further adjusted for educational level, body mass index, plasma low density lipoprotein-and high density lipoprotein-cholesterol, systolic and diastolic blood pressure levels, diabetes mellitus, cigarette smoking status, and pack-years of cigarette smoking (1.46 [95% C.I: 1.20 to 1.79]). The risk for adverse cardiac events increased monotonically from the first through the fourth quartile of vital exhaustion. The probabilities of adverse cardiac events over time were significantly higher in people with high vital exhaustion compared to those with low exhaustion (p = 0.002). In conclusion, vital exhaustion predicts the long-term risk for adverse cardiac events in men and women, independent of the established biomedical risk factors
Anger Proneness, Gender, and the Risk of Heart Failure
Evidence concerning the association of anger-proneness with incidence of heart failure is lacking
Evaluation of the impact of an augmented model of The Productive Ward: Releasing Time to Care on staff and patient outcomes: a naturalistic stepped-wedge trial
Background: Improving the quality and efficiency of healthcare is an international priority. A range of complex ward based quality initiatives have been developed over recent years, perhaps the most influential programme has been Productive Ward: Releasing Time to Care. The programme aims to improve work processes and team efficiency with the aim of āreleasing timeā, which would be used to increase time with patients ultimately improving patient care, although this does not form a specific part of the programme. This study aimed to address this and evaluate the impact using recent methodological advances in complex intervention evaluation design.Method: The objective of this study was to assess the impact of an augmented version of The Productive Ward: Releasing Time to Care on staff and patient outcomes. The design was a naturalistic stepped-wedge trial. The setting included fifteen wards in two acute hospitals in a Scottish health board region. The intervention was the Productive Ward: Releasing Time to Care augmented with practice development transformational change methods that focused on staff caring behaviours, teamwork and patient feedback. The primary outcomes included nursesā shared philosophy of care, nurse emotional exhaustion, and patient experience of nurse communication. Secondary outcomes covered additional key dimensions of staff and patient experience and outcomes and frequency of emergency admissions for same diagnosis within 6 months of discharge.Results: We recruited 691 patients, 177 nurses and 14 senior charge nurses. We found statistically significant improvements in two of the studyās three primary outcomes: patientsā experiences of nurse communication (Effect size=0.15, 95% CI; 0.05 to 0.24), and nursesā shared philosophy of care (Effect size =0.42, 95% CI; 0.14 to 0.70). There were also significant improvements in secondary outcomes: patientsā overall rating of ward quality; nursesā positive affect; and items relating to nursing team climate. We found no change in frequency of emergency admissions within six months of discharge.Conclusions: We found evidence that the augmented version of The Productive Ward: Releasing Time to Care Intervention was successful in improving a number of dimensions of nurse experience and ward culture, in addition to improved patient experience and evaluations of the quality of care received. Despite these positive summary findings across all wards, intervention implementation appeared to vary between wards. By addressing the contextual factors, which may influence these variations, and tailoring some elements of the intervention, it is likely that greater improvements could be achieved
Star Cluster Classification using Deep Transfer Learning with PHANGS-HST
Currently available star cluster catalogues from HST imaging of nearby
galaxies heavily rely on visual inspection and classification of candidate
clusters. The time-consuming nature of this process has limited the production
of reliable catalogues and thus also post-observation analysis. To address this
problem, deep transfer learning has recently been used to create neural network
models which accurately classify star cluster morphologies at production scale
for nearby spiral galaxies (D < 20 Mpc). Here, we use HST UV-optical imaging of
over 20,000 sources in 23 galaxies from the Physics at High Angular Resolution
in Nearby GalaxieS (PHANGS) survey to train and evaluate two new sets of
models: i) distance-dependent models, based on cluster candidates binned by
galaxy distance (9-12 Mpc, 14-18 Mpc, 18-24 Mpc), and ii) distance-independent
models, based on the combined sample of candidates from all galaxies. We find
that the overall accuracy of both sets of models is comparable to previous
automated star cluster classification studies (~60-80 per cent) and show
improvement by a factor of two in classifying asymmetric and multi-peaked
clusters from PHANGS-HST. Somewhat surprisingly, while we observe a weak
negative correlation between model accuracy and galactic distance, we find that
training separate models for the three distance bins does not significantly
improve classification accuracy. We also evaluate model accuracy as a function
of cluster properties such as brightness, colour, and SED-fit age. Based on the
success of these experiments, our models will provide classifications for the
full set of PHANGS-HST candidate clusters (N ~ 200,000) for public release.Comment: 16 pages, 10 figure
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