524 research outputs found

    Geometrical Expression of the Angular Resolution of a Network of Gravitational-Wave Detectors and Improved Localization Methods

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    We report for the first time a method-independent geometrical expression for the angular resolution of an arbitrary network of interferometric gravitational wave (GW) detectors when the arrival-time of a GW is unknown. We discuss the implications of our results on how to improve angular resolutions of a GW network and on improvements of localization methods. An example of an improvement to the null-stream localization method for GWs of unknown waveforms is demonstrated.Comment: Accepted for publication in JPCS, 2008, 7 page

    Spurious Shear in Weak Lensing with LSST

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    The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image \sim 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r27.5r\sim27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, \textit{additive} systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than 10\sim10' in the single short exposures, which propagates into a spurious shear correlation function at the 10410^{-4}--10310^{-3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.Comment: 22 pages, 12 figures, accepted by MNRA

    Neprilysin inhibition for pulmonary arterial hypertension: a randomized, double-blind, placebo-controlled, proof-of-concept trial

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    This is the peer reviewed version of the following article: Hobbs AJ, Moyes AJ, Baliga RS, et al. Neprilysin inhibition for pulmonary arterial hypertension: a randomized, double‐blind, placebo‐controlled, proof‐of‐concept trial. Br J Pharmacol. 2019. https://doi.org/10.1111/bph.14621, which has been published in final form at https://doi.org/10.1111/bph.14621. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThis work was supported by a British Heart Foundation Project Grant (PG/11/88/28992) and the National Institutes for Health Research, Comprehensive Biomedical Research Centre award to UC

    Rivaroxaban versus warfarin to treat patients with thrombotic antiphospholipid syndrome, with or without systemic lupus erythematosus (RAPS): a randomised, controlled, open-label, phase 2/3, non-inferiority trial.

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    BACKGROUND: Rivaroxaban is established for the treatment and secondary prevention of venous thromboembolism, but whether it is useful in patients with antiphospholipid syndrome is uncertain. METHODS: This randomised, controlled, open-label, phase 2/3, non-inferiority trial, done in two UK hospitals, included patients with antiphospholipid syndrome who were taking warfarin for previous venous thromboembolism, with a target international normalised ratio of 2·5. Patients were randomly assigned 1:1 to continue with warfarin or receive 20 mg oral rivaroxaban daily. Randomisation was done centrally, stratified by centre and patient type (with vs without systemic lupus erythematosus). The primary outcome was percentage change in endogenous thrombin potential (ETP) from randomisation to day 42, with non-inferiority set at less than 20% difference from warfarin in mean percentage change. Analysis was by modified intention to treat. Other thrombin generation parameters, thrombosis, and bleeding were also assessed. Treatment effect was measured as the ratio of rivaroxaban to warfarin for thrombin generation. This trial is registered with the ISRCTN registry, number ISRCTN68222801. FINDINGS: Of 116 patients randomised between June 5, 2013, and Nov 11, 2014, 54 who received rivaroxaban and 56 who received warfarin were assessed. At day 42, ETP was higher in the rivaroxaban than in the warfarin group (geometric mean 1086 nmol/L per min, 95% CI 957-1233 vs 548, 484-621, treatment effect 2·0, 95% CI 1·7-2·4, p<0·0001). Peak thrombin generation was lower in the rivaroxaban group (56 nmol/L, 95% CI 47-66 vs 86 nmol/L, 72-102, treatment effect 0·6, 95% CI 0·5-0·8, p=0·0006). No thrombosis or major bleeding were seen. Serious adverse events occurred in four patients in each group. INTERPRETATION: ETP for rivaroxaban did not reach the non-inferiority threshold, but as there was no increase in thrombotic risk compared with standard-intensity warfarin, this drug could be an effective and safe alternative in patients with antiphospholipid syndrome and previous venous thromboembolism

    Limits on Gravitational-Wave Emission from Selected Pulsars Using LIGO Data

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    We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multidetector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are the first direct upper limits for 26 of the 28 pulsars. We use coordinated radio observations for the first time to build radio-guided phase templates for the expected gravitational-wave signals. The unprecedented sensitivity of the detectors allows us to set strain upper limits as low as a few times 10^(-24). These strain limits translate into limits on the equatorial ellipticities of the pulsars, which are smaller than 10^(-5) for the four closest pulsars

    YwdL in Bacillus cereus: Its Role in Germination and Exosporium Structure

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    In members of the Bacillus cereus group the outermost layer of the spore is the exosporium, which interacts with hosts and the environment. Efforts have been made to identify proteins of the exosporium but only a few have so far been characterised and their role in determining spore architecture and spore function is still poorly understood. We have characterised the exosporium protein, YwdL. ΔywdL spores have a more fragile exosporium, subject to damage on repeated freeze-thawing, although there is no evidence of altered resistance properties, and coats appear intact. Immunogold labelling and Western blotting with anti-YwdL antibodies identified YwdL to be located exclusively on the inner surface of the exosporium of B. cereus and B. thuringiensis. We conclude that YwdL is important for formation of a robust exosporium but is not required to maintain the crystalline assembly within the basal layer or for attachment of the hairy nap structure. ΔywdL spores are unable to germinate in response to CaDPA, and have altered germination properties, a phenotype that confirms the expected defect in localization of the cortex lytic enzyme CwlJ in the coat

    Nanofabrication with Pulsed Lasers

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    An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics

    Atuação em ensino, pesquisa e extensão no Herbário do Instituto de Biologia da Universidade Federal do Rio de Janeiro

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    The Herbarium of the Department of Botany (RFA) of the Institute of Biology from the Federal University of Rio de Janeiro was created in 1954 by Professor Paulo Occhioni in oder to support teaching and research activities. The herbarium had its origin from collections gathered at the Medical School of Rio de Janeiro and it was represented by 794 exsiccates from the European Flora Collection by the botanist J.C. Ducommun. Subsequently, the collection has been expanded with samples from Flora of Rio de Janeiro acquired during periodic botanical expeditions. Currently, there are 45,260 specimens of plants and fungi in the herbarium. There are 118 nomenclatural types and two auxiliary collections, such as Carpotheque and Photo Library. RFA is a dynamic collection that focuses on scientific dissemination and other activities, such as teaching, extension and research, mainly because it is part of the University.El Herbario del Departamento de Botánica (RFA), del Instituto de Biología de la Universidade Federal do Rio de Janeiro (UFRJ), fue creado en 1954, por el profesor Paulo Occhioni, para servir en actividades de enseñanza e investigación. La colección comenzó a partir de colecciones recolectadas en la Facultad de Medicina de Río de Janeiro, representada por 794 exiccados de la Colección Europea de Flora por el botánico J.C. Ducommun. Posteriormente, la colección se incrementó con muestras de Flora de Río de Janeiro, resultado de excursiones botánicas periódicas. Actualmente hay 45,260 especímenes de todos los grupos de plantas y hongos en el herbario. Se destacan 118 tipos de nomenclatura y dos colecciones auxiliares, como Carpoteca y Fototeca. El RFA es una colección dinámica que se ocupa de la divulgación científica y las actividades que involucran la enseñanza, la extensión y la investigación, principalmente porque es parte de la universidad.L'Herbier du Département de botanique (RFA), de l'Institut de biologie de l' Universidade Federal do Rio de Janeiro (UFRJ), a été créé en 1954 par le professeur Paulo Occhioni, pour servir des activités d'enseignement et de recherche. La collection a commencé avec des collections collectées à la Faculté de médecine de Rio de Janeiro, représentées par 794 exsiccats de la Collection européenne de la flore par le botaniste J.C. Ducommun. Par la suite, la collection a été augmentée avec des échantillons de Flore de Rio de Janeiro, le résultat d'excursions botaniques périodiques. Actuellement, il y a 45,260 spécimens de tous les groupes de plantes et de champignons dans l'herbier. Il existe 118 types de nomenclature et deux collections auxiliaires, telles que Carpothèque et photothèque. RFA est une collection dynamique qui s'intéresse à la diffusion scientifique et aux activités qui impliquent l'enseignement, la vulgarisation et la recherche, principalement parce qu'elle fait partie de l'université.O Herbário do Departamento de Botânica (RFA), do Instituto de Biologia pertencente à Universidade Federal do Rio de Janeiro, foi criado em 1954, pelo professor Paulo Occhioni, para atender às atividades de ensino e pesquisa. A coleção teve início a partir das coletas resgatadas na Faculdade de Medicina do Rio de Janeiro, representadas por 794 exsicatas da Coleção da Flora Europeia do botânico J.C. Ducommun. Posteriormente, a coleção foi incrementada com amostras da Flora do Rio de Janeiro, resultado de excursões botânicas periódicas. Atualmente, constam no herbário 45.260 espécimes de todos os grupos vegetais e fungos. Destacam-se 118 tipos nomenclaturais e duas coleções auxiliares, como a Carpoteca e a Fototeca. O RFA é uma coleção dinâmica que se preocupa com a divulgação científica e com as atividades que envolvem o ensino, a extensão e a pesquisa, principalmente por ser parte da universidade

    First upper limits from LIGO on gravitational wave bursts

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    We report on a search for gravitational wave bursts using data from the first science run of the LIGO detectors. Our search focuses on bursts with durations ranging from 4 ms to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine-Gaussians) as a function of their root-sum-square strain h_{rss}; typical sensitivities lie in the range h_{rss} ~ 10^{-19} - 10^{-17} strain/rtHz, depending on waveform. We discuss improvements in the search method that will be applied to future science data from LIGO and other gravitational wave detectors.Comment: 21 pages, 15 figures, accepted by Phys Rev D. Fixed a few small typos and updated a few reference
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