410 research outputs found

    Dog Ownership and Dog Walking: The Relationship with Exercise, Depression and Hopelessness in Patients with Ischemic Heart Disease

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    Background: Dog ownership has been associated with increased physical activity in the general adult population. Objective: The objective of this study was to examine dog ownership and dog walking and their relationship with home-based and Phase II cardiac rehabilitation exercise, depression, and hopelessness in patients with ischemic heart disease (IHD). Methods: A total of 122 IHD patients were included in this prospective observational study. Patients completed dog ownership/walking questions during their hospitalization. The Cardiac Rehabilitation Exercise Participation Tool, Patient Health Questionaire-9 (PHQ-9), and State-Trait Hopelessness Scale were completed by mail at 3, 8, or 12 months later. Regression modeling was used to evaluate the significance of dog ownership/walking on exercise, depression and hopelessness. Results: The sample was 34.4% female and had a mean age of 64.7±9.1 years. Forty-two patients (34.4%) reported owning a dog. Patients who owned, but did not walk their dog, reported significantly lower levels of home exercise compared to patients who walked their dogs at least 1 day/week (non-dog walkers: 36.8% vs. dog walkers: 73.9%, p=0.019). The odds of participating in home exercise were significantly higher for dog walkers compared to non-dog walkers (OR 8.1 [1.7, 38.5] vs. 1.0). There were no differences in Phase II cardiac rehabilitation exercise, depression or hopelessness between dog owners and non-dog owners or between dog walkers and non-dog walkers. Conclusions: These findings show a beneficial effect on home-based exercise for those who dog-walk at least 1 day/week. Health care professionals should encourage dog walking to increase dog owners’ physical activity levels

    Impact of Home- and Hospital-Based Exercise in Cardiac Rehabilitation on Hopelessness in Patients With Coronary Heart Disease

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    Hopelessness is associated with increased adverse events and decreased survival in patients with coronary heart disease (CHD). The purpose of this research was to examine the effect of regular home- and hospital-based cardiac rehabilitation (CR) exercise on hopelessness levels in patients with CHD, hypothesizing that increased exercise in either setting would lead to decreased state hopelessness

    Ant-mediated seed dispersal in a warmed world

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    Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of eastern North America. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed dispersal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed

    Using physiology to predict the responses of ants to climatic warming

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    Physiological intolerance of high temperatures places limits on organismal responses to the temperature increases associated with global climatic change. Because ants are geographically widespread, ecologically diverse, and thermophilic, they are an ideal system for exploring the extent to which physiological tolerance can predict responses to environmental change. Here, we expand on simple models that use thermal tolerance to predict the responses of ants to climatic warming. We investigated the degree to which changes in the abundance of ants under warming reflect reductions in the thermal niche space for their foraging. In an eastern deciduous forest system in the United States with approximately 40 ant species, we found that for some species, the loss of thermal niche space for foraging was related to decreases in abundance with increasing experimental climatic warming. However, many ant species exhibited no loss of thermal niche space. For one well-studied species, Temnothorax curvispinosus, we examined both survival of workers and growth of colonies (a correlate of reproductive output) as functions of temperature in the laboratory, and found that the range of thermal tolerances for colony growth was much narrower than for survival of workers. We evaluated these functions in the context of experimental climatic warming and found that the difference in the responses of these two attributes to temperature generates differences in the means and especially the variances of expected fitness under warming. The expected mean growth of colonies was optimized at intermediate levels of warming (24°C above ambient); yet, the expected variance monotonically increased with warming. In contrast, the expected mean and variance of the survival of workers decreased when warming exceeded 4°C above ambient. Together, these results for T. curvispinosus emphasize the importance of measuring reproduction (colony growth) in the context of climatic change: indeed, our examination of the loss of thermal niche space with the larger species pool could be missing much of the warming impact due to these analyses being based on survival rather than reproduction. We suggest that while physiological tolerance of temperature can be a useful predictive tool for modeling responses to climatic change, future efforts should be devoted to understanding the causes and consequences of variability in models of tolerance calibrated with different metrics of performance and fitness. © The Author 2013. All rights reserved

    Heat tolerance predicts the importance of species interaction effects as the climate changes

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    Few studies have quantified the relative importance of direct effects of climate change on communities versus indirect effects that are mediated thorough species interactions, and the limited evidence is conflicting. Trait-based approaches have been popular in studies of climate change, but can they be used to estimate direct versus indirect effects? At the species level, thermal tolerance is a trait that is often used to predict winners and losers under scenarios of climate change. But thermal tolerance might also inform when species interactions are likely to be important because only subsets of species will be able to exploit the available warmer climatic niche space, and competition may intensify in the remaining, compressed cooler climatic niche space. Here, we explore the relative roles of the direct effects of temperature change and indirect effects of species interactions on forest ant communities that were heated as part of a large-scale climate manipulation at high-A nd low-latitude sites in eastern North America. Overall, we found mixed support for the importance of negative species interactions (competition), but found that the magnitude of these interaction effects was predictable based on the heat tolerance of the focal species. Forager abundance and nest site occupancy of heat-intolerant species were more often influenced by negative interactions with other species than by direct effects of temperature. Our findings suggest that measures of species-specific heat tolerance may roughly predict when species interactions will influence responses to global climate change

    Investigating Rurality as a Risk Factor for State and Trait Hopelessness in Hospitalized Patients with Ischemic Heart Disease

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    Background Rurality and hopelessness are each associated with increased mortality in adults with ischemic heart disease (IHD), yet there is no known research examining rurality as a risk factor for hopelessness in patients with IHD. This study evaluated rurality as a risk factor for state and trait hopelessness in adults hospitalized with IHD in samples drawn from the Great Lakes and Great Plains regions of the United States. Methods and Results A descriptive cross‐sectional design was used. Data were collected from 628 patients hospitalized for IHD in the Great Lakes (n=516) and Great Plains (n=112). Rural–Urban Commuting Area codes were used to stratify study participants by level of rurality. Levels of state hopelessness (measured by the State‐Trait Hopelessness Scale) were higher in rural patients (58.8% versus 48.8%; odds ratio [OR], 1.50; 95% CI, 1.03–2.18), a difference that remained statistically significant after adjusting for demographics, depression severity (measured by the Patient Health Questionnaire–8), and physical functioning (measured by the Duke Activity Status Index; OR, 1.59; 95% CI, 1.06–2.40; P=0.026). There was evidence of an interaction between marital status and rurality on state hopelessness after accounting for covariates (P=0.02). Nonmarried individuals had an increased prevalence of state hopelessness (nonmarried 72.0% versus married 52.0%) in rural areas (P=0.03). Conclusions Rural patients with IHD, particularly those who are nonmarried, may be at higher risk for state hopelessness compared with patients with IHD living in urban settings. Understanding rurality differences is important in identifying subgroups most at risk for hopelessness

    Climatic warming destabilizes forest ant communities

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    How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America. At the community level, warming consistently increased occupancy of nests and decreased extinction and nest abandonment. This consistency was largely driven by strong responses of a subset of thermophilic species at each site. As colonies of thermophilic species persisted in nests for longer periods of time under warmer temperatures, turnover was diminished, and species interactions were likely altered. We found that dynamical (Lyapunov) community stability decreased with warming both within and between sites. These results refute null expectations of simple temperature-driven increases in the activity and movement of thermophilic ectotherms. The reduction in stability under warming contrasts with the findings of previous studies that suggest resilience of species interactions to experimental and natural warming. In the face of warmer, no-analog climates, communities of the future May become increasingly fragile and unstable

    Functional skewing of the global CD8 T cell population in chronic hepatitis B virus infection

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    The inflamed liver in chronic hepatitis B virus (HBV) infection (CHB) is characterized by a large influx of non–virus-specific CD8 T cells. Little is known about the functional capacity of these lymphocytes, which could provide insights into mechanisms of failure of viral control and liver damage in this setting. We compared the effector function of total circulating and intrahepatic CD8 T cells in CHB patients and healthy donors. We demonstrated that CD8 T cells from CHB patients, regardless of their antigen specificity, were impaired in their ability to produce interleukin-2 and proliferate upon TCR-dependent stimulation. In contrast, these CD8 T cells had preserved production of the proinflammatory cytokines interferon-γ and tumor necrosis factor-α. This aberrant functional profile was partially attributable to down-regulation of the proximal T cell receptor signaling molecule CD3ζ, and could be corrected in vitro by transfection of CD3ζ or replenishment of the amino acid arginine required for its expression. We provide evidence for depletion of arginine in the inflamed hepatic microenvironment as a potential mechanism for these defects in global CD8 T cell signaling and function. These data imply that polarized CD8 T cells within the HBV-infected liver may impede proliferative antiviral effector function, while contributing to the proinflammatory cytokine environment

    The Planteome database:an integrated resource for reference ontologies, plant genomics and phenomics

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    The Planteome project (http://www.planteome.org) provides a suite of reference and species-specific ontologies for plants and annotations to genes and phenotypes. Ontologies serve as common standards for semantic integration of a large and growing corpus of plant genomics, phenomics and genetics data. The reference ontologies include the Plant Ontology, Plant Trait Ontology and the Plant Experimental Conditions Ontology developed by the Planteome project, along with the Gene Ontology, Chemical Entities of Biological Interest, Phenotype and Attribute Ontology, and others. The project also provides access to species-specific Crop Ontologies developed by various plant breeding and research communities from around the world. We provide integrated data on plant traits, phenotypes, and gene function and expression from 95 plant taxa, annotated with reference ontology terms. The Planteome project is developing a plant gene annotation platform; Planteome Noctua, to facilitate community engagement. All the Planteome ontologies are publicly available and are maintained at the Planteome GitHub site (https://github.com/Planteome) for sharing, tracking revisions and new requests. The annotated data are freely accessible from the ontology browser (http://browser.planteome.org/amigo) and our data repository

    FY17 Report Summaries of Five Completed Center Innovation Fund (CIF) Projects for the Highlights/Abstract Section of the FY 2018 CIF Annual Report

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    The Center Innovation Fund Annual Report for FY18 is an annual report for Space Technology Mission Directorate (STMD) Leadership, STMD Principle Technologists, and Center Innovation Fund Management. Attached is the Highlights/Abstract section of this annual report, which is the only section to be shared outside of NASA. Contributors were asked not to include any SBU information for these report summaries
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