1,721,103 research outputs found
Phylogeography link between Sicilian and Corso-Sardinian Testudo h. hermanni confirmed
Full text linkOur study confirms that Sicilian and Corso-Sardinian Testudo h. hermanni share a certain mtDNA haplotype, while tortoises from peninsular Italy harbour
slightly different haplotypes. When the fossil record is considered, this striking pattern
agrees well with the idea of local extinction in Corsica and Sardinia and later replacement by tortoises originating elsewhere, either by natural oversea dispersal or translocation by man
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
The profitability of Biodiesel with different organizations
No full textThe dir 30/2003 by fìxing the 5,75% target of biofuel incorporation to fossil fuel for vehiclei for 2010 has increased the interest for a further development of thè agro-energies in the EU and generated a virtuous competition among the Member States. Purpose of this paper is to analyze the dimension and profltability of the ìntegrated biodiesel chain wìth different organizations to evaluate their effectiveness in different industrial organization contest. Possible improvement of the economic performance is related with the constitution of local biofuel districts where clusters of farms producing oil seed are integrated with processors to reduce production-processin transport costs: evidences of the last 15 years suggest a decline up to 20% in current €. The 0ptimal size of plants with an higher level of exploitation of theìr capacity within an integrate organization is an important part of the cost-reducing process. This paper examines the theoretical plant size rules for a conventional processing business integrated in producer/processin enterprise, based on different forms of integration and the spatial dimension of the oilseed input market is examined for its consequences for the scale economies of biodiesel processing facilities. The analysis drives to the following conclusions: i)theoptimal size may grow further but the constrain is given by the supply of feedstock at farm level; ii) investment profitability measured with the return on capitai is convenient if the dimension of the supply area is appropriate to the processing capacity of the plant; ìii) the integrated cooperative network is improved to gain effìciency by reducing transaction costs; iv) the total producer plus processor profìts and sharing among partners change according with the type of organization used in the integrated chain
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Variation of Sicilian pond turtles, Emys trinacris – What makes a species cryptic?
No full textAbstract. Variation of the Sicilian pond turtle, Emys trinacris, is described, based on morphological data of more than 200 adult and immature turtles and mtDNA sequences of 31 new known-locality specimens. Emys trinacris is morphologically more variable than thought before. There exist pronounced population-specific differences. Adults are barely distinguishable from Emys orbicularis galloitalica. Hatchlings of E. trinacris are, however, significantly different patterned, allowing immediate species determination. Moreover, hatchlings of E. trinacris seem to be on average smaller and lighter than in E. orbicularis. This could be related with different reproductive strategies. Coloration polymorphism of adult Sicilian pond turtles comprises fair part of variation known in E. orbicularis. Thus, adult E. trinacris might have preserved the whole array of variation of the last common ancestor with E. orbicularis.We hypothesize that similarity of certain southern E. orbicularis subspecies and E. trinacris on one hand and pronounced differences in size, coloration and pattern of northern E. orbicularis
subspecies on the other result from stabilising selection in the north. While dark coloration and large body-size seem to be beneficial in the north, light coloration and small size could be simply not disadvantageous in the south, allowing coloration polymorphisms in E. trinacris and southern E. orbicularis subspecies. Further, the term ‘cryptic species’ and its meaning in regard to species concepts and bar-coding is discussed. It is concluded that species delineation based on mtDNA barcoding
requires application of a Phylogenetic Species Concept. Under the Biological Species Concept, animal mtDNA is not always an ideal tool for delineating species boundaries because taxa with monophyletic mitochondrial gene trees are neither
necessarily genetically isolated nor must represent the same Biological Species. Cryptic species are nothing special in nature because difficulties with their identification are due to deficits in cognitive abilities of man. This is illustrated by the fact that distinct live stages of ‘cryptic species’ may differ to various degrees from similar species, as is the case in hatchlings and adults of E. trinacris and E. o. galloitalica
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Diversità genetica e pattern filogeografici in Meuremys leprosa (Testudines, Geoemydidae)
No full textPreliminary data on distribution, morphometric and genetic characterization of Hermann’ tortoise in Sicily
No full textStand out from the crowd: Small-scale genetic structuring in the endemic sicilian pond turtle
Full text linkThe geographical pattern of genetic diversity was investigated in the endemic Sicilian pond turtle Emys trinacris across its entire distribution range, using 16 microsatellite loci. Overall, 245 specimens of E. trinacris were studied, showing high polymorphic microsatellite loci, with allele numbers ranging from 7 to 30. STRUCTURE and GENELAND analyses showed a noteworthy, geographically based structuring of the studied populations in five well-characterized clusters, supported by a moderate degree of genetic diversity (FST values between 0.075 and 0.160). Possible explanations for the genetic fragmentation observed are provided, where both natural and human-mediated habitat fragmentation of the Sicilian wetlands played a major role in this process. Finally, some conservation and management suggestions aimed at preventing the loss of genetic variability of the species are briefly reported, stressing the importance of considering the five detected clusters as independent Management Units
- …
