1,721,013 research outputs found
Studio della variabilità genetica di specie animali autoctone della Sardegna
No full textThis work aimed to know the genetics state of four Sardinian autochthonous animal species: two
mammalian species, the mouflon (Ovis gmelini musimon) and the Sardinian hare (Lepus capensis
mediterraneus), and two birds, the European shag (Phalacrocorax aristotelis desmarestii) and the griffon
(Gyps fulvus), in order to supply a method to monitories their welfare and the anthropic impact on these
animal colonies and to manage to preserve their genetic diversity. Firstly we manage to construct a simple
and atraumatic system to determine the sex in birds that do not show sexual dimorphism, such as griffon
and European shag. We used DNA extracted from feather and blood and the polymerase chain reaction to
assess a polymorphism of the sexual chromosom located Cromo Helicase DNA Binding 1 (CHDB1) gene. We
evidenced a sex specific pattern in both bird species and evidenced a distorted sex ratio in the newborns of
european shag populations of the north east of Sardinia. This phenomenon was due to the egg sex
managements of European shag females induced by the high death of males during fishing near fishing
nets. We used a molecular assessment of microsatellite markers to study population genetics of these
species. Our results showed that in all studied species there are troubles due to inbreeding and genetic drift
caused by decrease of animal numbers in each population and to the habitat fragmentation due to their
interaction with human activities
Nuovi approcci per la valutazione della qualità dei gameti
Full text linkThe aim of our study was to use metabolomic and proteomic technologies to evaluate quality parameters of male and female gametes using ovine and equine as models. We evaluate 1) metabolomic factors in seminal plasma of subfertile rams pharmacologically treated with melatonin using capillary electrophoresis (CE) and mass spectrometry. We measured melatonin concentration in seminal plasma and evidenced its increase till 90 days after treatment. Parallelly to melatonin seminal plasma concentration it was affected carnitine and acetylcarnitine and some aminoacids that could be used as biomarkers of sperm quality; 2) Sperm quality and ATP concentration in stallions of different ages using capillary electrophoresys and UV determination. Our data did not evidence any difference between different experimental groups.3) Spermatozoa ATP concentration by CE with UV and seminal plasma proteomics using 2D-PAGE, in subfertile stallions carrying lower sperm viability and motility. Obtained data did not evidence differences in ATP concentration but it were showed differences in protein patterns; 3)ATP and protein patterns during maturation of ovine oocytes with different developmental competence using CE with LIF and 2D-PAGE respectively. ATP was showed a determining factor responsible to protein synthesis delay, meiotic cycle timing and embryo quality. Our study evidenced the reliable use of metabolomics and proteomics to determine male and female gametes quality
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
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
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
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