130,470 research outputs found
An evaluation of the use of 4-methylumbelliferyl-beta-D-glucuronide (MUG) in different solid media for the detection and enumeration of Escherichia coli in foods
No full textAbstract: The use of 4-methylumbelliferyl-beta-D-glucuronide (MUG) in different solid media for the detection and enumeration of Escherichia roll in foods was evaluated by; testing the effects of different substrate concentrations (50 or 100 mu g ml(-1)), incubation temperatures (37 or 41.5 degrees C) and incubation times (8, 12, 24 and 48 h). Different kinds of foods, both naturally and artificially contaminated, were analysed. The use of selective media without differential substances and an incubation time of 24 h Seem to be worthy of recommendation. In this case an incubation temperature of 37 degrees C would be preferred and the MUG concentration could be reduced to 50 mu g ml(-1). Incubation times: shorter than 24 h, which may cause a loss of sensitivity, require higher incubation temperatures (41.5 degrees C) and MUG concentration (100 mu g ml(-1))
Masonry differential settlements analysis including the soil
No full textIn the present paper, a novel approach is proposed to investigate the effects of differential settlements on masonry structures modelling the construction as a no-tension material, and, more importantly, directly considering the soil-structure interaction with an explicit modelling of the unilateral contact between soil and structure. The soil behaviour is included by a boundary integral approach, thus avoiding mesh discretisation issues. Some numerical examples will be shown to demonstrate the efficiency of the procedure
A survey of SiC power MOSFETs short-circuit robustness and failure mode analysis
No full textThe aim of this paper is to provide an extensive overview about the state-of-art commercially available SiC power MOSFET, focusing on their short-circuit ruggedness. A detailed literature investigation has been carried out, in order to collect and understand the latest research contribution within this topic and create a survey of the present scenario of SiC MOSFETs reliability evaluation and failure mode analysis, pointing out the evolution and improvements as well as the future challenges in this promising device technology
Robustness of MW-Level IGBT modules against gate oscillations under short circuit events
No full textThe susceptibility of MW-level IGBT power modules to critical gate voltage oscillations during short circuit events has been evidenced experimentally. This paper proposes a sensitivity analysis method to better understand the oscillating behavior dependence on different operating conditions (i.e., collector-emitter voltage, gate-emitter voltage and temperature). A study case on 1.7 kV/1 kA IGBT power modules is presented. The proposed study helps to understand the oscillation mechanism by revealing its relationship with different working conditions. Moreover, the study can be helpful to understand the oscillation phenomenon, as well as to further improve the device performance during short circuit
Association of Vitamin D deficiency with peripheral arterial disease: a meta-analysis of literature studies
No full textVitamin D deficiency patients have an increased cardiovascular (CV) morbidity and mortality. Contrasting data are available about the association between peripheral arterial disease (PAD) and Vitamin D status
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
An evaluation of the use of 4-methylumbelliferyl-beta-D-glucuronide (MUG) in different solid media for the detection and enumeration of Escherichia coli in foods
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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