31 research outputs found

    Super-Hubble de Sitter Fluctuations and the Dynamical RG

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    Perturbative corrections to correlation functions for interacting theories in de Sitter spacetime often grow secularly with time, due to the properties of fluctuations on super-Hubble scales. This growth can lead to a breakdown of perturbation theory at late times. We argue that Dynamical Renormalization Group (DRG) techniques provide a convenient framework for interpreting and resumming these secularly growing terms. In the case of a massless scalar field in de Sitter with quartic self-interaction, the resummed result is also less singular in the infrared, in precisely the manner expected if a dynamical mass is generated. We compare this improved infrared behavior with large-N expansions when applicable.Comment: 33 pages, 4 figure

    Extragalactic Inverse Compton Light from Dark Matter Annihilation and the Pamela Positron Excess

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    We calculate the extragalactic diffuse emission originating from the up-scattering of cosmic microwave photons by energetic electrons and positrons produced in particle dark matter annihilation events at all redshifts and in all halos. We outline the observational constraints on this emission and we study its dependence on both the particle dark matter model (including the particle mass and its dominant annihilation final state) and on assumptions on structure formation and on the density profile of halos. We find that for low-mass dark matter models, data in the X-ray band provide the most stringent constraints, while the gamma-ray energy range probes models featuring large masses and pair-annihilation rates, and a hard spectrum for the injected electrons and positrons. Specifically, we point out that the all-redshift, all-halo inverse Compton emission from many dark matter models that might provide an explanation to the anomalous positron fraction measured by the Pamela payload severely overproduces the observed extragalactic gamma-ray background.Comment: Version accepted for publication in JCAP, one new figure and text added; 19 pages, 5 figure

    Systematic Review of Medicine-Related Problems in Adult Patients with Atrial Fibrillation on Direct Oral Anticoagulants

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    New oral anticoagulant agents continue to emerge on the market and their safety requires assessment to provide evidence of their suitability for clinical use. There-fore, we searched standard databases to summarize the English language literature on medicine-related problems (MRPs) of direct oral anticoagulants DOACs (dabigtran, rivaroxban, apixban, and edoxban) in the treatment of adults with atri-al fibrillation. Electronic databases including Medline, Embase, International Pharmaceutical Abstract (IPA), Scopus, CINAHL, the Web of Science and Cochrane were searched from 2008 through 2016 for original articles. Studies pub-lished in English reporting MRPs of DOACs in adult patients with AF were in-cluded. Seventeen studies were identified using standardized protocols, and two reviewers serially abstracted data from each article. Most articles were inconclusive on major safety end points including major bleeding. Data on major safety end points were combined with efficacy. Most studies inconsistently reported adverse drug reactions and not adverse events or medication error, and no definitions were consistent across studies. Some harmful drug effects were not assessed in studies and may have been overlooked. Little evidence is provided on MRPs of DOACs in patients with AF and, therefore, further studies are needed to establish the safety of DOACs in real-life clinical practice

    Characterization of in- and near-body radio frequency transmission loss for biomedical implants

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    10.1166/jmihi.2013.1140Journal of Medical Imaging and Health Informatics31112-11

    Channel characterization of walking passerby's effects on 2.48-GHz wireless body area network

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    10.1109/TAP.2012.2230231IEEE Transactions on Antennas and Propagation6131495-1498IETP

    Phenotypic and genomic survey on organic acid utilization profile of Pseudomonas mendocina strain S5.2, a vineyard soil isolate

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    Root exudates are chemical compounds that are released from living plant roots and provide significant energy, carbon, nitrogen and phosphorus sources for microbes inhabiting the rhizosphere. The exudates shape the microflora associated with the plant, as well as influences the plant health and productivity. Therefore, a better understanding of the trophic link that is established between the plant and the associated bacteria is necessary. In this study, a comprehensive survey on the utilization of grapevine and rootstock related organic acids were conducted on a vineyard soil isolate which is Pseudomonas mendocina strain S5.2. Phenotype microarray analysis has demonstrated that this strain can utilize several organic acids including lactic acid, succinic acid, malic acid, citric acid and fumaric acid as sole growth substrates. Complete genome analysis using single molecule real-time technology revealed that the genome consists of a 5,120,146 bp circular chromosome and a 252,328 bp megaplasmid. A series of genetic determinants associated with the carbon utilization signature of the strain were subsequently identified in the chromosome. Of note, the coexistence of genes encoding several iron–sulfur cluster independent isoenzymes in the genome indicated the importance of these enzymes in the events of iron deficiency. Synteny and comparative analysis have also unraveled the unique features of d-lactate dehydrogenase of strain S5.2 in the study. Collective information of this work has provided insights on the metabolic role of this strain in vineyard soil rhizosphere
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