1,720,965 research outputs found
Population genetic analysis of the endemic Centaurea spp. in Sardinia
Get PDFTyrrhenian Islands are one of Mediterranean hotspots. Within the Mediterranean basin the
Sardinian-Corsican system shows one of the highest densities of endemic plant species, therefore it
is so original in terms of vegetation cover. Limited information is available on the genetic structure
of endemic Mediterranean plant species. Several species are known as palaeo-endemics because the
island could have played a significant role during the last glacial maximum, and as schizo-endemics
because a great number of endemic species could be evolved after the actual separation of Sardinia
from the mainland and from Corsica, ended 20,000 years ago. On 347 endemic species 45.8% are
exclusive to Sardinia. Among these, five species of the Centaurea genus are present: C. horrida, C.
filiformis, C. corensis, C. ferulacea and C. magistrorum.
Microendemic vicariants is a term used for groups of endemic plants whose parentage is
obvious and which are specially rather than genetically isolated. In these plants, morphological
differentiation is usually weak and the groups are not widely separated geographically. Populations
have been fragmented into discrete units, and often the morphological differences between taxa,
although small, are constant. As some cases of microendemic, presumably schizo-endemic, species
are present within the Centaurea genus in western Mediterranean, we would here assess the genetic
variability of Sardinian endemic Centaurea species and their taxonomical relationships
Studi demografici e genetici su specie vegetali di interesse per la conservazione in Sardegna
Get PDFIl Bacino del Mediterraneo è uno deglihotspotsdi
biodiversità a livello globale (Myerset al., 2000),
infatti risulta terzo al mondo per l’abbondante presenza
di piante endemiche (circa 13.000 specie esclusive
che corrispondono al 4,3% di tutte le piante del
mondo). All’interno dell’area mediterranea sono
state individuate 10 aree cruciali per la conservazione
e gestione della biodiversità (Médail, Quézel,
1999), hotspots che rappresentano il 22% (circa
515.000 Km2) della superficie totale dell’area mediterranea,
includono circa 5.500 entità endemiche e
presentano una ricchezza floristica superiore a 2.000
specie/15.000 Km2(Médail, Quézel, 1999).In questo ambito il Dipartimento di Botanica ed
Ecologia vegetale dell’Università degli Studi di
Sassari ha intrapreso studi di tipo demografico e
genetico sulla dinamica e vitalità delle popolazioni di
entità incluse nell’All. II della Direttiva Habitat o che
identificano habitat comunitari ai sensi dell’All. I
della stessa Direttiva, finalizzati alla loro conservazione.
In questa sede si riportano dati preliminari suCentaurea horridaBadarò (Pisanu, Filigheddu,
2005; Mameliet al., 2006),Anchusa crispaViv. ed
entità congeneriche (Farriset al., 2006) eTaxus baccataL. (Farris, Filigheddu, 2005)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
