65 research outputs found

    Self-synchronized duty-cycling for sensor networks with energy harvesting capabilities: Implementation in Wiselib

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    In this work we present a protocol for a self- synchronized duty-cycling mechanism in wireless sensor net- works with energy harvesting capabilities. The protocol is im- plemented in Wiselib, a library of generic algorithms for sensor networks. Simulations are conducted with the sensor network simulator Shawn. They are based on the specifications of real hardware known as iSense sensor nodes. The experimental results show that the proposed mechanism is able to adapt to changing energy availabilities. Moreover, it is shown that the system is very robust against packet loss.Postprint (published version

    Sex-specific association of cardiovascular drug doses with adverse outcomes in atrial fibrillation.

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    OBJECTIVES Sex differences occur in atrial fibrillation (AF), including age at first manifestation, pathophysiology, treatment allocation, complication rates and quality of life. However, optimal doses of cardiovascular pharmacotherapy used in women with AF with or without heart failure (HF) are unclear. We investigated sex-specific associations of beta-blocker and renin-angiotensin system (RAS) inhibitor doses with cardiovascular outcomes in patients with AF or AF with concomitant HF. METHODS We used data from the prospective Basel Atrial Fibrillation and Swiss Atrial Fibrillation cohorts on patients with AF. The outcome was major adverse cardiovascular events (MACEs), including death, myocardial infarction, stroke, systemic embolisation and HF-related hospitalisation. Predictors of interest were spline (primary analysis) or quartiles (secondary analysis) of beta-blocker or RAS inhibitor dose in per cent of the maximum dose (reference), in interaction with sex. Cox models were adjusted for demographics, comorbidities and comedication. RESULTS Among 3961 patients (28% women), MACEs occurred in 1113 (28%) patients over a 5-year median follow-up. Distributions of RAS inhibitor and beta-blocker doses were similar in women and men. Cox models revealed no association between beta-blocker dose or RAS inhibitor dose and MACE. In a subgroup of patients with AF and HF, the lowest hazard of MACE was observed in women prescribed 100% of the RAS inhibitor dose. However, there was no association between RAS dose quartiles and MACE. CONCLUSIONS In this study of patients with AF, doses of beta-blockers and RAS inhibitors did not differ by sex and were not associated with MACE overall

    Public opinion and environmental policy output: a cross-national analysis of energy policies in Europe

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    This article studies how public opinion is associated with the introduction of renewable energy policies in Europe. While research increasingly seeks to model the link between public opinion and environmental policies, the empirical evidence is largely based on a single case: the US. This limits the generalizability of findings and we argue accordingly for a systematic, quantitative study of how public opinion drives environmental policies in another context. Theoretically, we combine arguments behind the political survival of democratic leaders with electoral success and environmental politics. Ultimately, we suggest that office-seeking leaders introduce policies that seem favorable to the domestic audience; if the public prefers environmental protection, the government introduces such policies in turn. The main contribution of this research is the cross-country empirical analysis, where we combine data on the public's environmental attitudes and renewable energy policy outputs in a European context between 1974 and 2015. We show that as public opinion shifts towards prioritizing the environment, there is a significant and positive effect on the rate of renewable energy policy outputs by governments in Europe. To our knowledge, this is the first systematic, quantitative study of public opinion and environmental policies across a large set of countries, and we demonstrate that the mechanisms behind the introduction of renewable energy policies follow major trends across European states

    Millennial changes in North American wildfire and soil activity over the last glacial cycle

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    Climate changes in the North Atlantic region during the last glacial cycle were dominated by the slow waxing and waning of the North American ice sheet as well as by intermittent Dansgaard-­‐Oeschger (DO) events. However prior to the last deglaciation, little is known about the response of North American vegetation to such rapid climate changes and especially about the response of biomass burning, an important factor for regional changes in radiative forcing. Here we use continuous, high-­‐resolution ammonium (NH4+) records derived from the NGRIP and GRIP ice cores to document both North American NH4+ background emissions from soils and wildfire frequency over the last 110,000 yr. Soil emissions increased on orbital timescales with warmer climate, related to the northward expansion of vegetation due to reduced ice-­‐covered areas. During Marine Isotope Stage (MIS) 3 DO warm events, a higher fire recurrence rate is recorded, while NH4+ soil emissions rose only slowly during longer interstadial warm periods, in line with slow ice sheet shrinkage and delayed ecosystem changes. Our results indicate that sudden warming events had little impact on NH4+ soil emissions and NH4+ aerosol transport to Greenland during the glacial but triggered a significant increase in the frequency of fire occurrence.This paper has greatly benefitted from the Sir Nicholas Shackleton fellowship, Clare Hall, University of Cambridge, U.K., awarded to HF in 2014. The Division for Climate and Environmental Physics, Physics Institute, University of Bern acknowledges the long-­‐term financial support of ice core research by the Swiss National Science Foundation (SNSF) and the Oeschger Centre for Climate Change Research. EW is supported by a Royal Society professorship. NGRIP is directed and organized by the Department of Geophysics at the Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen. It is supported by funding agencies in Denmark (SNF), Belgium (FNRS-­‐CFB), France (IPEV and INSU/CNRS), Germany (AWI), Iceland (RannIs), Japan (MEXT), Sweden (SPRS), Switzerland (SNSF) and the USA (NSF, Office of Polar Programs).This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ngeo249

    The Private Equity Premium Puzzle Revisited: New Evidence on the Role of Heterogeneous Risk Attitudes

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    The empirical finding that entrepreneurs tend to invest a large share of their wealth in their own firms despite comparably low returns and high risk has become known as the private equity premium puzzle. This paper provides evidence supporting the hypothesis that lower risk aversion of entrepreneurs, and not necessarily credit constraints, may explain this puzzle. The analysis is based on a large, representative panel data set for Germany, which provides information on asset portfolios and experimentally validated risk attitudes. The results show that both the ownership probability and the conditional portfolio share of private business equity significantly increase with higher risk tolerance

    Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

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    Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

    GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

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    Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment
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