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Genetic differentiation and introgression in the Ochthebius quadricollis complex (Coleptera, Hydraenidae)
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Evoluzione dell'isolamento riproduttivo nel complesso Ochthebius quadricollis (Coleoptera, Hydraenidae)
No full textPopulation structure of Aedes albopictus (Skuse): the mosquito which is colonizing Mediterranean countries
No full textMultilocus electrophoresis analysis has been used to study the genetic structure of 18 populations of Aedes albopictus newly introduced to Italy, in comparison with two populations in the United States, four in Japan, and four in Indonesia. Allozyme analysis revealed that 15 out of the 18 studied loci were polymorphic among the 28 populations. No significant deviations from Hardy-Weinberg equilibrium were found at polymorphic loci. High genetic affinity was observed between the Italian populations and those from the United States and Japan. The analysis of variance in allele frequencies showed that variance among subpopulations accounted for most of the total variance, suggesting that isolation of the Italian populations is not related to distance. Analysis of linkage disequilibrium using Ohta's method shows that the variance in the frequency of allele combinations could be explained by the action of the genetic drift which accompanies the establishment of new populations. The colonization process of Ae. albopictus in Italy is following a trend similar to that previously observed in the U.S.A., probably because both infestations derive from several successive introductions, each with large numbers of individuals
Electrophoretic analytical technique for the identification of mycorrhizal fungi of the genus Tuber and their mycelium and mycorrhiza
No full textTruffles are ectomycorrhizic hypogean fungi of the Ascomycotina (Order Tuberales). They are particularly known for their edible fruitbodies (ascocarps) where the reproductive structures are localized. The life cycle starts with a mycelium germinating from spores or conidia in the soil, and when a host plant is present a second stage can follow with an ectomycorrhiza developing on the roots of plants. If the environmental conditions are suitable a final stage is the development of a fruitbody
Reproductive isolation and introgression between beetles of the Ochthebius quadricollis complex (Coleptera, Hydraenidae)
No full textMolecular re-examination of the taxonomy of Ochthebius (Coleoptera:Hydraenidae) from the Mediterranean and Macaronesian regions.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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