318 research outputs found
Solar fusion cross sections. II. The pp chain and CNO cycles
We summarize and critically evaluate the available data on nuclear fusion
cross sections important to energy generation in the Sun and other
hydrogen-burning stars and to solar neutrino production. Recommended values and
uncertainties are provided for key cross sections, and a recommended spectrum
is given for 8B solar neutrinos. We also discuss opportunities for further
increasing the precision of key rates, including new facilities, new
experimental techniques, and improvements in theory. This review, which
summarizes the conclusions of a workshop held at the Institute for Nuclear
Theory, Seattle, in January 2009, is intended as a 10-year update and
supplement to Reviews of Modern Physics 70 (1998) 1265.Comment: 54 pages, 20 figures, version to be published in Reviews of Modern
Physics; various typos corrected and several updates mad
Antithrombotic Therapy in Patients with Acute Coronary Syndrome in the Intermountain Heart Collaborative Study
Objective. To determine factors associated with single antiplatelet (SAP) or dual antiplatelet (DAP) therapy and anticoagulants (AC) use in hospital and after discharge among patients with acute coronary syndrome (ACS). Methods. We evaluated 5,294 ACS patients in the Intermountain Heart Collaborative Study from 2004 to 2009. Multivariable logistic regressions were used to determine predictors of AC or AP use. Results. In hospital, 99% received an AC, 79% DAP, and 19% SAP; 78% had DAP + AC. Coronary stents were the strongest predictors of DAP use in hospital compared to SAP (P<0.001). After discharge, 77% received DAP, 20% SAP, and 9% AC; 5% had DAP + AC. DAP compared to SAP was less likely for patients on AC (odds ratio [OR] = 0.30, P<0.0001) after discharge. Placement of a stent increased the likelihood of DAP (bare metal: OR = 54.8, P<0.0001; drug eluting: OR = 59.4, P<0.0001). 923 had atrial fibrillation and 337 had a history of venous thromboembolism; these patients had increased use of AC (29% and 40%, resp.). Conclusion. While in-hospital use of AC was nearly universal, postdischarge AC use was rare. Concern for providing the best antithrombotic therapy, while maintaining an acceptable bleeding risk, may explain the selection decisions
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Interplanetary magnetic field properties and variability near Mercury's orbit
The first extensive study of interplanetary magnetic field (IMF) characteristics and stability at Mercury is undertaken using MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) magnetometer data. Variations in IMF and solar wind conditions have a direct and rapid effect upon Mercury's highly dynamic magnetosphere; hence, understanding of the time scales over which these variations occur is crucial because they determine the duration of magnetospheric states. We characterize typical distributions of IMF field strength, clock angle, and cone angle throughout the duration of MESSENGER's mission. Clock and cone angle distributions collected during the first Earth year of the mission indicate that there was a significant north-south asymmetry in the location of the heliospheric current sheet during this period. The stability of IMF magnitude, clock angle, cone angle, and IMF Bz polarity is quantified for the entire mission. Changes in IMF Bz polarity and magnitude are found to be less likely for higher initial field magnitudes. Stability in IMF conditions is also found to be higher at aphelion (heliocentric distance r ∼ 0.31 AU) than at perihelion (r ∼ 0.47 AU)
Attenuated Stress Response to Acute Restraint and Forced Swimming Stress in Arginine Vasopressin 1b Receptor Subtype (Avpr1b) Receptor Knockout Mice and Wild-Type Mice Treated with a Novel Avpr1b Receptor Antagonist
Arginine vasopressin (AVP) synthesised in the parvocellular region of the hypothalamic paraventricular nucleus and released into the pituitary portal vessels acts on the 1b receptor subtype (Avpr1b) present in anterior pituitary corticotrophs to modulate the release of adrenocorticotrophic hormone (ACTH). Corticotrophin-releasing hormone is considered the major drive behind ACTH release; however, its action is augmented synergistically by AVP. To determine the extent of vasopressinergic influence in the hypothalamic-pituitary-adrenal axis response to restraint and forced swimming stress, we compared the stress hormone levels [plasma ACTH in both stressors and corticosterone (CORT) in restraint stress only] following acute stress in mutant Avpr1b knockout (KO) mice compared to their wild-type controls following the administration of a novel Avpr1b antagonist. Restraint and forced swimming stress-induced increases in plasma ACTH were significantly diminished in mice lacking a functional Avpr1b and in wild-type mice that had been pre-treated with Avpr1b antagonist. A corresponding decrease in plasma CORT levels was also observed in acute restraint-stressed knockout male mice, and in Avpr1b-antagonist-treated male wild-type mice. By contrast, plasma CORT levels were not reduced in acutely restraint-stressed female knockout animals, or in female wild-type animals pre-treated with Avpr1b antagonist. These results demonstrate that pharmacological antagonism or inactivation of Avpr1b causes a reduction in the hypothalamic-pituitary-adrenal (HPA) axis response, particularly ACTH, to acute restraint and forced swimming stress, and show that Avpr1b knockout mice constitute a model by which to study the contribution of Avpr1b to the HPA axis response to acute stressors
Integrating knowledge exchange and the assessment of dryland management alternatives – A learning-centered participatory approach
The adoption of sustainable land management strategies and practices that respond to current climate and human pressures requires both assessment tools that can lead to better informed decision-making and effective knowledge-exchange mechanisms that facilitate new learning and behavior change. We propose a learning-centered participatory approach that links land management assessment and knowledge exchange and integrates science-based data and stakeholder perspectives on both biophysical and socio-economic attributes. We outline a structured procedure for a transparent assessment of land management alternatives, tailored to dryland management, that is based on (1) principles of constructivism and social learning, (2) the participation of stakeholders throughout the whole assessment process, from design to implementation, and (3) the combination of site-specific indicators, identified by local stakeholders as relevant to their particular objectives and context conditions, and science-based indicators that represent ecosystem services of drylands worldwide. The proposed procedure follows a pattern of eliciting, challenging, and self-reviewing stakeholder perspectives that aims to facilitate learning. The difference between the initial baseline perspectives and the final self-reviewed stakeholder perspectives is used as a proxy of learning. We illustrate the potential of this methodology by its application to the assessment of land uses in a Mediterranean fire-prone area in East Spain. The approach may be applied to a variety of socio-ecological systems and decision-making and governance scales.The PRACTICE protocol was developed in the framework of the project PRACTICE: Prevention and Restoration Actions to Combat Desertification. An integrated Assessment, funded by the European Commission (GA226818). This research was also funded by the European project CASCADE (GA283068), and the Marie Skłodowska-Curie Actions Fellowship of the European Union (GA 629677) “S4S, Science for Society Solutions”, awarded to B.J.O
Complex Coacervate-based Materials for Biomedicine
There has been increasing interest in complex coacervates for deriving and trans- porting biomaterials. Complex coacervates are a dense, polyelectrolyte-rich liq- uid that results from the electrostatic complexation of oppositely charged macroions. Coacervates have long been used as a strategy for encapsulation, par- ticularly in food and personal care products. More recent efforts have focused on the utility of this class of materials for the encapsulation of small molecules, pro- teins, RNA, DNA, and other biomaterials for applications ranging from sensing to biomedicine. Furthermore, coacervate-related materials have found utility in other areas of biomedicine, including cartilage mimics, tissue culture scaffolds, and adhesives for wet, biological environments. Here, we discuss the self- assembly of complex coacervate-based materials, current challenges in the intel- ligent design of these materials, and their utility applications in the broad field of biomedicine
Incidence and prevalence of patellofemoral pain: a systematic review and meta-analysis
Background: Patellofemoral pain is considered one of the most common forms of knee pain, affecting adults, adolescents, and physically active populations. Inconsistencies in reported incidence and prevalence exist and in relation to the allocation of healthcare and research funding, there is a clear need to accurately understand the epidemiology of patellofemoral pain.
Methods: An electronic database search was conducted, as well as grey literature databases, from inception to June 2017. Two authors independently selected studies, extracted data and appraised methodological quality. If heterogeneous, data were analysed descriptively. Where studies were homogeneous, data were pooled through a meta-analysis.
Results: 23 studies were included. Annual prevalence for patellofemoral pain in the general population was reported as 22.7%, and adolescents as 28.9%. Incidence rates in military recruits ranged from 9.7 – 571.4/1,000 person-years, amateur runners in the general population at 1080.5/1,000 person-years and adolescents amateur athletes 5.1% - 14.9% over 1 season. One study reported point prevalence within military populations as 13.5%. The pooled estimate for point prevalence in adolescents was 7.2% (95% Confidence Interval: 6.3% - 8.3%), and in female only adolescent athletes was 22.7% (95% Confidence Interval 17.4% - 28.0%).
Conclusion: This review demonstrates high incidence and prevalence levels for patellofemoral pain. Within the context of this, and poor long term prognosis and high disability levels, PFP should be an urgent research priority
Communication Impairments in Mice Lacking Shank1: Reduced Levels of Ultrasonic Vocalizations and Scent Marking Behavior
Autism is a neurodevelopmental disorder with a strong genetic component. Core symptoms are abnormal reciprocal social interactions, qualitative impairments in communication, and repetitive and stereotyped patterns of behavior with restricted interests. Candidate genes for autism include the SHANK gene family, as mutations in SHANK2 and SHANK3 have been detected in several autistic individuals. SHANK genes code for a family of scaffolding proteins located in the postsynaptic density of excitatory synapses. To test the hypothesis that a mutation in SHANK1 contributes to the symptoms of autism, we evaluated Shank1−/− null mutant mice for behavioral phenotypes with relevance to autism, focusing on social communication. Ultrasonic vocalizations and the deposition of scent marks appear to be two major modes of mouse communication. Our findings revealed evidence for low levels of ultrasonic vocalizations and scent marks in Shank1−/− mice as compared to wildtype Shank1+/+ littermate controls. Shank1−/− pups emitted fewer vocalizations than Shank1+/+ pups when isolated from mother and littermates. In adulthood, genotype affected scent marking behavior in the presence of female urinary pheromones. Adult Shank1−/− males deposited fewer scent marks in proximity to female urine than Shank1+/+ males. Call emission in response to female urinary pheromones also differed between genotypes. Shank1+/+ mice changed their calling pattern dependent on previous female interactions, while Shank1−/− mice were unaffected, indicating a failure of Shank1−/− males to learn from a social experience. The reduced levels of ultrasonic vocalizations and scent marking behavior in Shank1−/− mice are consistent with a phenotype relevant to social communication deficits in autism.National Institute of Mental Health (U.S.) (Intramural Research Program)Simons Foundatio
Obesity, metabolic factors and risk of different histological types of lung cancer: A Mendelian randomization study.
BACKGROUND: Assessing the relationship between lung cancer and metabolic conditions is challenging because of the confounding effect of tobacco. Mendelian randomization (MR), or the use of genetic instrumental variables to assess causality, may help to identify the metabolic drivers of lung cancer.
METHODS AND FINDINGS: We identified genetic instruments for potential metabolic risk factors and evaluated these in relation to risk using 29,266 lung cancer cases (including 11,273 adenocarcinomas, 7,426 squamous cell and 2,664 small cell cases) and 56,450 controls. The MR risk analysis suggested a causal effect of body mass index (BMI) on lung cancer risk for two of the three major histological subtypes, with evidence of a risk increase for squamous cell carcinoma (odds ratio (OR) [95% confidence interval (CI)] = 1.20 [1.01-1.43] and for small cell lung cancer (OR [95%CI] = 1.52 [1.15-2.00]) for each standard deviation (SD) increase in BMI [4.6 kg/m2]), but not for adenocarcinoma (OR [95%CI] = 0.93 [0.79-1.08]) (Pheterogeneity = 4.3x10-3). Additional analysis using a genetic instrument for BMI showed that each SD increase in BMI increased cigarette consumption by 1.27 cigarettes per day (P = 2.1x10-3), providing novel evidence that a genetic susceptibility to obesity influences smoking patterns. There was also evidence that low-density lipoprotein cholesterol was inversely associated with lung cancer overall risk (OR [95%CI] = 0.90 [0.84-0.97] per SD of 38 mg/dl), while fasting insulin was positively associated (OR [95%CI] = 1.63 [1.25-2.13] per SD of 44.4 pmol/l). Sensitivity analyses including a weighted-median approach and MR-Egger test did not detect other pleiotropic effects biasing the main results.
CONCLUSIONS: Our results are consistent with a causal role of fasting insulin and low-density lipoprotein cholesterol in lung cancer etiology, as well as for BMI in squamous cell and small cell carcinoma. The latter relation may be mediated by a previously unrecognized effect of obesity on smoking behavior
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