130,502 research outputs found
Rapid identification of Mycobacterium tubercolosis and Mycobacterium avium by Polymerase Chain Reaction and Restriction Enzyme Analysis within sigma factor region.
No full textMeSH 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
Naltrexone, beta-endorphins and immune system.
No full textNaltrexone, beta-endorphins and immune system. Evaluation of B-endorphin plasma levels in 40 patiens (40 heroin addicts, 32 of them seropositive for HIV
"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.
A Carbon-13 Nmr Study Of New 4-substituted Neostigmine Methyl Sulphates: Correlations Of Substituent-induced Chemical Shifts With Substituent Parameters
No full textThe Carbon-13 NMR spectra of six new neostigimine derivatives, the 4-substituted-3-[{N,N-dimethylamino)carbonyl}oxy]-N′,N′,N′-tri methylbenzen-amminium methyl sulphates (4-substituted neostigmine methyl sulphates), and of the parent compound were recorded, and unequivocal chemical shift assignments through the use of HETCOR and COLOC sequences were performed. Large intramolecular interaction chemical shifts (ICS) were observed for carbon C-3 (-8.3 to +3.1 ppm), attachment site of the OC(O)N(CH3)2 group, and moderate ICS values (-3.3 to +3.5 ppm) for the remaining ring carbons, similarly to the values which were found for C-1 (-9.3 to +3.4 ppm) and for C-2 to C-6 (-3.0 to +3.8 ppm) of the corresponding 2-substituted-5-N′,N′-dimethylaminophenyl-N,N-dimethylcarbamates. Correlation analyses for the substituent-induced chemical shifts (SCS) with several sets of substituent parameters were carried out, through SSP, DSP and DSP-NLR treatments, as well as through multiple regression analysis. Good correlations were found for all ring carbons (r>0.97) and for the carbonyl carbon (r 0.9797). Resonance contribution is predominant for C-1 and C-2, while the electronegativity or inductive parameter is significant or the prevailing component for all ring carbons. Negative r values were found for several correlations (reverse substituent effect).453X65Stedman, E., (1929) Biochem, 23, p. 17Aeschlimann, J.A., Reinert, M., (1931) J. Pharmacol.exp.ther., 43, p. 413Millner O.E., Jr., Stanley, J.W., Purcell, W.P., (1974) J. Med. Chem., 17, p. 13Hetnarski, B., O'Brien, R.D., (1975) J. Agric. Food Chem., 23, p. 709Yamagami, C., Takao, N., Nishioka, T., Fujita, T., Takeuchi, Y., (1984) Org. Magn. Res., 22, p. 439Yamagami, C., Sonoda, C., Takao, N., Tanaka, M., Yamada, J., Horisaka, K., Fujita, T., (1982) Chem. Pharm. Bull., 30, p. 4175Perjessy, A., Jones, R.G., McClair, S.L., Wilkins, M., (1983) J. Org. Chem., 48, p. 1266Rittner, R., Barbarini, J.E., Höehr, N.F., (2000), accepted by Pharmazie for publication in 06/09Höehr, N.F., (1993), Ph. D. Thesis, Universidade Estadual de Campinas(1985) Statgraphics, Statistical Graphics System, , STSC Inc., UtahJackman, L.M., Sternhell, S., (1969) Applications of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry, 2nd Ed., , Pergamon Press, OxfordRittner, R., Barbarini, J.E., Höehr, N.F., (1999) Can. J. Anal. Sci. Spectrosc., 44, p. 181Breitmaier, E., Voelter, W., (1987) Carbon-13 NMR Spectroscopy, 3rd Ed., , VCH, WeinheimRittner, R., Barbarini, J.E., (1998) Can. J. Anal. Sci. Spectrosc., 43, p. 14Duddeck, H., (1987) Top. Stereochem., 16, p. 219Yamagami, C., Sai, T., Takao, N., (1987) Aust. J. Chem., 40, p. 2005Bromilow, J., Brownlee, R.T.C., Craik, D.J., Sadek, M., Taft, R.W., (1980) J. Org. Chem., 45, p. 2429Exner, O., Dahn, H., Péchy, P., (1992) Magn. Reson. Chem., 30, p. 381Exner, O., (1988) Correlation Analysis of Chemical Data, , Plenum, New YorkBromilow, J., Brownlee, R.T.C., Craik, D.J., Fiske, P.R., Rowe, J.E., Sadek, M., (1981) J. Chem. Soc., Perkin Trans.2, p. 753Canto, E.L., (1996), Ph. D. Thesis, Universidade Estadual de Campina
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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