1,720,990 research outputs found
Feeding strategy of the Sacoglossan Opisthobranch Oxynoe olivacea on the tropical green alga Caulerpa taxifolia
No full textInfestazione da Plerocercoidi di Pterobothrium sp. (Cestoda, Pterobothriidae) in Xyrichthys novacula
No full textAspects of reproductive biology of Mediterranean amberjack (Seriola dumerilii Risso, 1810): gonadal development.
No full textWild Seriola dumerilii juveniles (77.3 +_ 23 g total body weight, 17.4 f 1.8 cm standard length; 2-3 months of age), were caught in the Eolian Island and reared in floating cages for a 14 months period. Gonads were collected routineously and submitted to histological and histochemical analysis to study the type and timing of gonadal differentiation and development. The histological examination shows that sex differentiation is clearly expressed in juveniles 23-25.5 cm long, 4-5 months old. A "differentiated" development was detected, as sexes early differentiate into female or male. In both sexes, anatomical and cytological differentiation proceed in parallel. Gonadal differentiation is completely achieved by the end of the first year of age. Within this period also cytological differentiation was completed in reared males, whereas females do not show the secondary growth phase oocytes. These findings agree with the previous data on wild S. dumerilii caught in natural environment. Comparing data reported by other Authors, gonadal development seems to be linked to fish size more than to age. Gonadal development in cage-reared fish was continuous and no pathological or degenerative signs were histologically observed. From an aquaculture perspective cage rearing conditions, being similar to the natural ones, seem to be suitable to correctly develop and manage broodstock in captivit
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
Aspects of reproductive biology of the Mediterranean amberjack (Seriola dumerilii Risso) during the spawning period
No full textWild Seriola dumerilii were collected in the South Mediterranean Sea during the 1990, 1991 and 1992 spawning seasons. Macroscopic and cytological characteristics of ovary and testis were analysed. Depending on the presence and the number of oocytes at different stages, a five point maturity scale was proposed for ovarian maturity. Nine maturity stages of the oocytes are described. Oocyte size-frequency distribution has shown a group synchronous ovarian development type. The testes have a typical lobular-type structure. Depending on lobules and sperm duct development and on the abundance of germ cells, testis maturity was classified in four stages. Maturity rate according to age and size was also determined. 100% of 1-year-old fish show immature gonads. The proportion of females with mature ovaries was 0, 12.5, 84.6 and 100% at the age of 2, 3, 4 and 5 years respectively. The proportion of males with mature testes was 14.3, 40, 80 and 100 at the same age. The median standard length at which 50% of the fish attained maturity is 109 and 113 cm SL in males and females respectively
Biology and fisheries of little tunny Euthynnus alletteratus, (Rafinesque, 1910) along Sicilian coasts.
No full textBiology and fisheries of bluefish Pomatomus saltatrix (Linneus, 1776) along Sicilian coasts.
No full textA study on bill fish (Pomatomus saltatrix) fischery has been carried out between 1994 and 1995 in the Southern Tyrrhenian sea and in the Sicilian Strait area. The species growth, feeding, habit and reproductive biology have been studies too. The study aims at assessing importance of the bill fish for the commercial fishery and at proposing resource exploitation strategy
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