1,721,026 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
The 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
Genetic characterization of Dirofilaria repens and D. immitis by electrophoretic analysis of gene-enzyme systems.
A multilocus genetic analysis based on protein electrophoresis was carried out on 39 adult specimens of Dirofilaria repens and 31 of D. immitis. Seventeen enzymatic loci provided reliable electrophoretic patterns which were compared in the two species. All loci except one were monomorphic. Fixed alternative allozymes were found at 13 loci while only 3 loci shared apparently the same allozyme in the two species. The polymorphic locus, Pgm, also showed alternative allozymes. This remarkably high genetic divergence, which presumably reflects a very old speciation process, allows an easy characterization of D. repens and D. immitis and supports their classification in the subgenera Nochtiella and Dirofilaria, respectively
Genetic distance between two sibling species of the Aedes mariae complex (Diptera, Culicidae)
Uneven distribution of sandflies in areas with contrasting incidence of classic Kaposi's sarcoma.
Amylin given by central and peripheral routes inhibits acid gastric secretion
The effect of rat amylin on acid gastric secretion in the pylorus-ligated, unanesthetized rat system (Shay test) was examined. Amylin administered peripherally (2.5, 5, 10, 40, 100, or 160 micrograms/kg, SC) or intracerebroventricularly (1.5, 2.7, or 5 micrograms/rat, ICV) decreased acid gastric secretion in a dose-dependent manner. Central administration of amylin gave a stronger suppression of gastric secretion than peripheral injection. In addition, ICV-injected amylin inhibited insulin-stimulated acid gastric secretion and was effective in suppressing acid gastric secretion in rats depleted of somatostatin by pretreatment with cysteamine. This study suggests that amylin may participate in the central regulation of acid gastric secretion and indicates a possible biological function of amylin as a gastrointestinal peptide
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