134,979 research outputs found
Vitamin D deficiency: A potential risk factor for Clostridium difficile infection
No full textDima Youssef,1 William B Grant,2 Alan N Peiris3,41Department of Internal Medicine, Division of Infectious Diseases, 2Sunlight, Nutrition and Health Research Center, San Francisco, CA USA; 3Department of Medicine, Mountain Home VAMC, 4Department of Medicine, East Tennessee State University, Johnson City, Tennessee, USAIn the July 3, 2012 issue of the journal of Risk Management and Healthcare Policy, Martinez et al present a nice review on Clostridium difficile (C. difficile) infections.1 The different manifestations of this challenging disease along with the high cost and burden on the health care system were discussed. While the authors did an admirable job in discussing traditional risk factors, they do not mention vitamin D deficiency.View original paper by Martinez and colleagues
A simple quadratic nodal model for hexagonal geometry
No full textThesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1992.Includes bibliographical references (leaves 99-102).by Youssef A. Shatilla.Sc.D
Analysis of deep excavations in clay
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1992.Includes bibliographical references.by Youssef M.A. Hashash.Ph.D
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
Going 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.
R&D in Cleaner Technology and International Trade
No full textWe consider a dynamic three-stage game played by two regulator-firm hierarchies to capture the scale and technological effects of opening markets to international trade. Each firm produces one good sold on the market. Firms can invest in R&D in order to lower their fixed emission/output ratio and are regulated with costly public funds. We take the context of sufficiently high market sizes and investment cost parameters. Opening markets to international trade yields more investment in R&D, more production and a lower emission ratio. When the market size is low enough and the investment cost parameter is high enough, pollution in common market is higher than in autarky. International trade reduces the social welfare.R&D, Cleaner technology, Common market, Social welfare
Transboundary Pollution, R&D Spillovers and International Trade
No full textWe consider a symmetric three-stage game played by a pair of regulator-firm hierarchies to capture the scale and technology effects. Each firm produces one good sold on the market. The production process generates pollution characterized by a fixed emission/output ratio, and cross-borders. Firms can invest in R&D in order to lower their emission/output ratio, and this activity is characterized by positive R&D spillovers. We show that R&D spillovers and the competition of firms on the common market help non-cooperating countries to internalize transboundary pollution more efficiently. Consequently, in most cases, when the positive externality increases, the levels of R&D and production increase while pollution decreases, implying an increase of the social welfare. However, in some other cases, pollution under common market increases with the R&D externality implying a decrease of the social welfare. Opening markets to the international trade leads to more investment in R&D and more production. In most cases, pollution under common market is lower than under autarky, implying a greater social welfare. Nevertheless, in some other cases, pollution under common market is higher than under autarky implying that opening markets deteriorates social welfare.Transboundary pollution, R&D spillovers, common market, social welfare
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