2,697 research outputs found

    In defense of Bacillus thuringiensis, the safest and most successful microbial insecticide available to humanity – a response to EFSA

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    This is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this record.The Bacillus cereus group contains vertebrate pathogens such as Bacillus anthracis and Bacillus cereus and the invertebrate pathogen Bacillus thuringiensis. Microbial biopesticides based on B. thuringiensis (Bt) are widely recognized as being among the safest and least environmentally damaging insecticidal products available. Nevertheless, a recent food poisoning incident prompted a European Food Safety Authority review which argued that B. thuringiensis poses a health risk equivalent to B. cereus, a causative agent of diarrhoea. However, a critical examination of available data, and this latest incident, provide no solid evidence that B. thuringiensis causes diarrhoea. Although relatively high levels of B. cereus-like spores can occur in foods, genotyping demonstrates that these are predominantly naturally-occurring strains rather than biopesticides. Moreover, MLST genotyping of >2000 isolates show that biopesticidegenotypes have never been isolated from any clinical infection. MLST data demonstratethat Bacillus cereus group is heterogeneous and formed of distinct clades withsubstantial differences in biology, ecology and host association. The group posing the greatest risk (the anthracis clade) is distantly related to the clade containing allbiopesticides. These recent data support the long-held view that B. thuringiensis, andespecially the strains used in Bt biopesticides, are very safe for humans.BR has received support from NERC, BBSRC and the Leverhulme Trust for funding his research on Bt

    Non Relational Models for the Management of Large Amount of Astronomical Data

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    The objective of this paper is the comparison between two different database typologies: the relational and the nonrelational architecture, in the context of the applications related to the use and distribution of astronomical data. The specific context is focused to problems quite different from those related to administrative and managerial environments within which were developed the leading technologies on which are based the modern systems of massive storage of data. The data provided by astronomical instrumentation are usually filtered out by the front-end system (trigger, anticoincidence, DSP etc.), so they do not require special controls of congruence. Moreover, the related storage systems must be able to ensure an easy growth, minimizing human systemistic interventions and automating the related actions. The use of a non-relational architecture (NoSQL), offers great advantages during the insertion of informations within a data base, while the response speed of the queries is mainly tied to their type and complexity

    Three-dimensional carrier-dynamics simulation of terahertz emission from photoconductive switches

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    A semi-classical Monte Carlo model for studying three-dimensional carrier dynamics in photoconductive switches is presented. The model was used to simulate the process of photoexcitation in GaAs-based photoconductive antennas illuminated with pulses typical of mode-locked Ti:Sapphire lasers. We analyzed the power and frequency bandwidth of THz radiation emitted from these devices as a function of bias voltage, pump pulse duration and pump pulse location. We show that the mechanisms limiting the THz power emitted from photoconductive switches fall into two regimes: when illuminated with short duration (<40 fs) laser pulses the energy distribution of the Gaussian pulses constrains the emitted power, while for long (>40 fs) pulses, screening is the primary power-limiting mechanism. A discussion of the dynamics of bias field screening in the gap region is presented. The emitted terahertz power was found to be enhanced when the exciting laser pulse was in close proximity to the anode of the photoconductive emitter, in agreement with experimental results. We show that this enhancement arises from the electric field distribution within the emitter combined with a difference in the mobilities of electrons and holes.Comment: 7 pages, 7 figure

    Superradiance from BEC vortices: a numerical study

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    The scattering of sound wave perturbations from vortex excitations of Bose-Einstein condensates(BEC) is investigated by numerical integration of the associated Klein-Gordon equation. It is found that, at sufficiently high angular speeds, sound wave-packets can extract a sizeable fraction of the vortex energy through a mechanism of superradiant scattering. It is conjectured that this superradiant regime may be detectable in BEC experiments.Comment: 4 pages, 4 figure

    Brachial Artery Constriction during Brachial Artery Reactivity Testing Predicts Major Adverse Clinical Outcomes in Women with Suspected Myocardial Ischemia: Results from the NHLBI-Sponsored Women's Ischemia Syndrome Evaluation (WISE) Study

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    Background:Limited brachial artery (BA) flow-mediated dilation during brachial artery reactivity testing (BART) has been linked to increased cardiovascular risk. We report on the phenomenon of BA constriction (BAC) following hyperemia.Objectives:To determine whether BAC predicts adverse CV outcomes and/or mortality in the women's ischemic Syndrome Evaluation Study (WISE). Further, as a secondary objective we sought to determine the risk factors associated with BAC.Methods:We performed BART on 377 women with chest pain referred for coronary angiography and followed for a median of 9.5 years. Forearm ischemia was induced with 4 minutes occlusion by a cuff placed distal to the BA and inflated to 40mm Hg > systolic pressure. BAC was defined as >4.8% artery constriction following release of the cuff. The main outcome was major adverse events (MACE) including all-cause mortality, non-fatal MI, non-fatal stroke, or hospitalization for heart failure.Results:BA diameter change ranged from -20.6% to +44.9%, and 41 (11%) women experienced BAC. Obstructive CAD and traditional CAD risk factors were not predictive of BAC. Overall, 39% of women with BAC experienced MACE vs. 22% without BAC (p=0.004). In multivariate Cox proportional hazards regression, BAC was a significant independent predictor of MACE (p=0.018) when adjusting for obstructive CAD and traditional risk factors.Conclusions:BAC predicts almost double the risk for major adverse events compared to patients without BAC. This risk was not accounted for by CAD or traditional risk factors. The novel risk marker of BAC requires further investigation in women. © 2013 Sedlak et al

    LANDSLIDE SUSCEPTIBILITY ASSESSMENT: SOIL MOISTURE MONITORING DATA PROCESSED BY AN AUTOMATIC PROCEDURE IN GIS FOR 3D DESCRIPTION OF THE SOIL SHEAR STRENGTH

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    Abstract. Slope stability is strongly influenced by soil hydraulic conditions. Considering rain-triggered shallow landslides, the stability can be markedly influenced by the propagation of the saturation front inside the unsaturated zone. Soil shear strength varies in the vadose zone depending on the type of soil and the variations of soil moisture. Monitoring of the unsaturated zone can be done by measuring volumetric water content using low-cost instrumentation, such as capacitive sensors that are easy to manage and provide data in near-real time. For a proper soil moisture assessment a laboratory soil-specific calibration of the sensors is recommended. Knowing the soil water content, the suction parameter can be estimated by a Water Retention Curve (WRC), and consequently the soil shear strength in unsaturated conditions is evaluated. Several models are already proposed for shallow landslide susceptibility evaluation, also in FOSS GIS environment. However, these models do not usually consider the soil shear strength in unsaturated conditions, even if it is crucial, especially in the case of shallow landslides. A procedure that allows the estimate of the soil shear strength starting from soil moisture monitoring data (from sensor networks or satellite-derived map) is here presented. Moreover, preliminary results relative to a case study (i.e. the landslide of Ceriana-Mainardo in Italy) are shown. The proposed procedure could be integrated into existing models for landslide susceptibility assessment and also for the emergency management

    Monitoring of Rain-Induced Landslides for the Territory Protection: The AD-VITAM Project

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    The authors refer in this paper some of the analyses already done and the planned activities in developing the AD-VITAM Project (InterReg V-A France \u2013 Italy \u2013 E.U. ALCOTRA), which aims to assess the most suitable techniques to obtain a reliable forecasting of rain-induced landslides, in order to enhance the territorial resilience when subject to such a risk. The authors refers about the procedure called LAMP (Landslides Monitoring and Predicting), consisting in an Integrated Hydrological/Geotechnical numerical model (IHG) fed by site-specific installed sensor-network, to help in the start-up calibration of some of the relevant parameters used by the model. The tuned-up simulation models is used to assess the landslide susceptibility to measured/predicted rainfall histories. The implementation of the numerical geotechnical/hydrological models on a GIS platform with regard to some of the selected sites, and the preliminary tests performed on the sensors to be installed on-site in order to monitor the real-time response to rainfalls are briefly described. Thanks to the effective cooperation with the local technicians and the project partners, the final achievements of AD-VITAM could furnish a real support to a better protection of both the natural and the urbanized environments, allowing site-specific warnings and a better hydro-geological risk management capacity

    SEA WATER TURBIDITY ANALYSIS FROM SENTINEL-2 IMAGES: ATMOSPHERIC CORRECTION AND BANDS CORRELATION

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    Turbidity is a visual property of water, related to the presence of suspended particles in waters. This parameter is measured in different water quality monitoring programmes as it can determine negative environmental effects both on the biotic and abiotic marine ecosystem. Traditional methods, e.g., in situ monitoring, offer high accuracy but provide sparse information in space and time. On the other hand, Earth Observation (EO) techniques have the potential to provide a comprehensive, fast and inexpensive monitoring system to observe the biophysical and biochemical conditions of water bodies. In the present work, a method for seawater turbidity retrieval from Sentinel-2 multispectral optical images, freely available within the EU Copernicus programme, is presented. The study explores different atmospheric correction methods available in open source software (QGIS, GRASS GIS and SNAP), in order to convert Level-1C (L1C) Top-Of-Atmosphere (TOA) images to Level-2A (L2A) Bottom-Of-Atmosphere (BOA), when the latter is not directly available. Once the proper method for atmospheric correction was identified and applied, the correlation between the in situ dataset and the individual bands known to be most sensitive to water turbidity, i.e., blue (B2), green (B3), red (B4) and near infrared (B8 and B8A) bands, were investigated and a linear regression model between selected band values and turbidity was identified

    Oscillation of water table due to rainfall: an experience of modeling in GIS

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    A physically-based Integrated Hydrological-Geotechnical model (IHG) able to assess the rainfallinduced landslide susceptibility was developed, refined and applied in GIS environment along the past years (Passalacqua, 2002; Federici et al., 2014; Bovolenta et al., 2016), showing its reliability. It is a useful instrument to landslide susceptibility evaluations and land-use planning over wide areas. The present paper focuses on the modeling of water table oscillation due to rainfall, comparing different hydrological models
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