184 research outputs found

    Simulated Fire Behavior and Fine-Scale Forest Structure Following Conifer Removal in Aspen-Conifer Forests in the Lake Tahoe Basin, USA

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    Quaking aspen is found in western forests of the United States and is currently at risk of loss due to conifer competition at within-stand scales. Wildfires in these forests are impactful owing to conifer infilling during prolonged fire suppression post-Euro-American settlement. Here, restoration cuttings seek to impact wildfire behavior and aspen growing conditions. In this study, we explored how actual and hypothetical cuttings with a range of conifer removal intensity altered surface fuel and overstory structure at stand and fine scales. We then simulated wildfires, examining fire behavior and effects on post-fire forest structures around aspen trees. We found that conifer removal constrained by lower upper diameter limits (\u3c56 cm) had marginal effects on surface fuel and overstory structure, likely failing to enhance resource conditions sufficiently to sustain aspen. Increasing the diameter limit also led to a higher likelihood of fire spread and a higher rate of spread, owing to greater within-canopy wind speed, though crown fire activity decreased. Our simulations suggest heavier treatments could facilitate reintroduction of fire while also dampening the effects of wildfires on forest structure. Cutting specifications that relax diameter limits and remove a substantial portion of conifer overstory could better promote aspen restoration and mitigate fire hazard

    Effects of Climate Oscillations on Wildland Fire Potential in the Continental United States

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    The effects of climate oscillations on spatial and temporal variations in wildland fire potential in the continental U.S. are examined from 1979 to 2015 using cyclostationary empirical orthogonal functions (CSEOFs). The CSEOF analysis isolates effects associated with the modulated annual cycle and the El Nino-Southern Oscillation (ENSO). The results show that, in early summer, wildland fire potential is reduced in the southwest during El Nino but is increased in the northwest, with opposite trends for La Nina. In late summer, El Nino is associated with increased wildland fire potential in the southwest. Relative to the mean, the largest impacts of ENSO are observed in the northwest and southeast. Climate impacts on fire potential due to ENSO are found to be most closely associated with variations in relative humidity. The connections established here between fire potential and climate oscillations could result in improved wildland fire risk assessment and resource allocation

    Hsa-miR-196a2 Rs11614913 Polymorphism Contributes to Cancer Susceptibility: Evidence from 15 Case-Control Studies

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    BACKGROUND: MicroRNAs (miRNAs) are a family of endogenous, small and noncoding RNAs that negatively regulate gene expression by suppressing translation or degrading mRNAs. Recently, many studies investigated the association between hsa-miR-196a2 rs11614913 polymorphism and cancer risk, which showed inconclusive results. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a meta-analysis of 15 studies that included 9,341 cancer cases and 10,569 case-free controls. We assessed the strength of the association, using odds ratios (ORs) with 95% confidence intervals (CIs). Overall, individuals with the TC/CC genotypes were associated with higher cancer risk than those with the TT genotype (OR=1.18, 95% CI=1.03-1.34, P<0.001 for heterogeneity test). In the stratified analyses, we observed that the CC genotype might modulate breast cancer risk (OR=1.11, 95%CI=1.01-1.23, Pheterogeneity=0.210) and lung cancer risk (OR=1.25, 95%CI=1.06-1.46, Pheterogeneity=0.958), comparing with the TC/TT genotype. Moreover, a significantly increased risk was found among Asian populations in a dominant model (TC/CC versus TT, OR=1.24, 95% CI=1.07-1.43, Pheterogeneity=0.006). CONCLUSIONS: These findings supported that hsa-miR-196a2 rs11614913 polymorphism may contribute to the susceptibility of cancers

    Integrating plant physiology into simulation of fire behavior and effects

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    Wildfires are a global crisis, but current fire models fail to capture vegetation response to changing climate. With drought and elevated temperature increasing the importance of vegetation dynamics to fire behavior, and the advent of next generation models capable of capturing increasingly complex physical processes, we provide a renewed focus on representation of woody vegetation in fire models. Currently, the most advanced representations of fire behavior and biophysical fire effects are found in distinct classes of fine-scale models and do not capture variation in live fuel (i.e. living plant) properties. We demonstrate that plant water and carbon dynamics, which influence combustion and heat transfer into the plant and often dictate plant survival, provide the mechanistic linkage between fire behavior and effects. Our conceptual framework linking remotely sensed estimates of plant water and carbon to fine-scale models of fire behavior and effects could be a critical first step toward improving the fidelity of the coarse scale models that are now relied upon for global fire forecasting. This process-based approach will be essential to capturing the influence of physiological responses to drought and warming on live fuel conditions, strengthening the science needed to guide fire managers in an uncertain future

    The ARCH Projects: design and rationale (IAASSG 001)

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    OBJECTIVE A number of factors limit the effectiveness of current aortic arch studies in assessing optimal neuroprotection strategies, including insufficient patient numbers, heterogenous definitions of clinical variables, multiple technical strategies, inadequate reporting of surgical outcomes and a lack of collaborative effort. We have formed an international coalition of centres to provide more robust investigations into this topic. METHODS High-volume aortic arch centres were identified from the literature and contacted for recruitment. A Research Steering Committee of expert arch surgeons was convened to oversee the direction of the research. RESULTS The International Aortic Arch Surgery Study Group has been formed by 41 arch surgeons from 10 countries to better evaluate patient outcomes after aortic arch surgery. Several projects, including the establishment of a multi-institutional retrospective database, randomized controlled trials and a prospectively collected database, are currently underway. CONCLUSIONS Such a collaborative effort will herald a turning point in the surgical management of aortic arch pathologies and will provide better powered analyses to assess the impact of varying surgical techniques on mortality and morbidity, identify predictors for neurological and operative risk, formulate and validate risk predictor models and review long-term survival outcomes and quality-of-life after arch surger

    International Society of Sports Nutrition Position Stand: protein and exercise

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    Abstract Position statement The International Society of Sports Nutrition (ISSN) provides an objective and critical review related to the intake of protein for healthy, exercising individuals. Based on the current available literature, the position of the Society is as follows: 1) An acute exercise stimulus, particularly resistance exercise, and protein ingestion both stimulate muscle protein synthesis (MPS) and are synergistic when protein consumption occurs before or after resistance exercise. 2) For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, a value that falls in line within the Acceptable Macronutrient Distribution Range published by the Institute of Medicine for protein. 3) There is novel evidence that suggests higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass). 4) Recommendations regarding the optimal protein intake per serving for athletes to maximize MPS are mixed and are dependent upon age and recent resistance exercise stimuli. General recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20–40 g. 5) Acute protein doses should strive to contain 700–3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of the essential amino acids (EAAs). 6) These protein doses should ideally be evenly distributed, every 3–4 h, across the day. 7) The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting (at least 24 h), but likely diminishes with increasing time post-exercise. 8) While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training. 9) Rapidly digested proteins that contain high proportions of essential amino acids (EAAs) and adequate leucine, are most effective in stimulating MPS. 10) Different types and quality of protein can affect amino acid bioavailability following protein supplementation. 11) Athletes should consider focusing on whole food sources of protein that contain all of the EAAs (i.e., it is the EAAs that are required to stimulate MPS). 12) Endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance; the addition of protein may help to offset muscle damage and promote recovery. 13) Pre-sleep casein protein intake (30–40 g) provides increases in overnight MPS and metabolic rate without influencing lipolysis

    International Society of Sports Nutrition Position Stand: protein and exercise

    Get PDF
    Abstract Position statement The International Society of Sports Nutrition (ISSN) provides an objective and critical review related to the intake of protein for healthy, exercising individuals. Based on the current available literature, the position of the Society is as follows: 1) An acute exercise stimulus, particularly resistance exercise, and protein ingestion both stimulate muscle protein synthesis (MPS) and are synergistic when protein consumption occurs before or after resistance exercise. 2) For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, a value that falls in line within the Acceptable Macronutrient Distribution Range published by the Institute of Medicine for protein. 3) Higher protein intakes (2.3–3.1 g/kg/d) may be needed to maximize the retention of lean body mass in resistance-trained subjects during hypocaloric periods. 4) There is novel evidence that suggests higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass). 5) Recommendations regarding the optimal protein intake per serving for athletes to maximize MPS are mixed and are dependent upon age and recent resistance exercise stimuli. General recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20–40 g. 6) Acute protein doses should strive to contain 700–3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of the essential amino acids (EAAs). 7) These protein doses should ideally be evenly distributed, every 3–4 h, across the day. 8) The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting (at least 24 h), but likely diminishes with increasing time post-exercise. 9) While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training. 10) Rapidly digested proteins that contain high proportions of essential amino acids (EAAs) and adequate leucine, are most effective in stimulating MPS. 11) Different types and quality of protein can affect amino acid bioavailability following protein supplementation. 12) Athletes should consider focusing on whole food sources of protein that contain all of the EAAs (i.e., it is the EAAs that are required to stimulate MPS). 13) Endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance; the addition of protein may help to offset muscle damage and promote recovery. 14) Pre-sleep casein protein intake (30–40 g) provides increases in overnight MPS and metabolic rate without influencing lipolysis

    International Society of Sports Nutrition Position Stand: Protein and Exercise

    Get PDF
    Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review related to the intake of protein for healthy, exercising individuals. Based on the current available literature, the position of the Society is as follows: 1) An acute exercise stimulus, particularly resistance exercise, and protein ingestion both stimulate muscle protein synthesis (MPS) and are synergistic when protein consumption occurs before or after resistance exercise. 2) For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, a value that falls in line within the Acceptable Macronutrient Distribution Range published by the Institute of Medicine for protein. 3) There is novel evidence that suggests higher protein intakes (\u3e3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass). 4) Recommendations regarding the optimal protein intake per serving for athletes to maximize MPS are mixed and are dependent upon age and recent resistance exercise stimuli. General recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20–40 g. 5) Acute protein doses should strive to contain 700–3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of the essential amino acids (EAAs). 6) These protein doses should ideally be evenly distributed, every 3–4 h, across the day. 7) The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting (at least 24 h), but likely diminishes with increasing time post-exercise. 8) While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training. 9) Rapidly digested proteins that contain high proportions of essential amino acids (EAAs) and adequate leucine, are most effective in stimulating MPS. 10) Different types and quality of protein can affect amino acid bioavailability following protein supplementation. 11) Athletes should consider focusing on whole food sources of protein that contain all of the EAAs (i.e., it is the EAAs that are required to stimulate MPS). 12) Endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance; the addition of protein may help to offset muscle damage and promote recovery. 13) Pre-sleep casein protein intake (30–40 g) provides increases in overnight MPS and metabolic rate without influencing lipolysis

    ISSN exercise & sport nutrition review: research & recommendations

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    Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients

    Towards Equitable, Diverse, and Inclusive science collaborations: The Multimessenger Diversity Network

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