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Size at sexual maturity of the spider crab Anamathia Rissoana (Roux, 1828) (Decapoda: Majoidea) from the Sardinian sea
No full textThis study relates to the size at morphological and physiological sexual maturity of the deep sea crab Anamathia rissoana. Between August 1997 to July 2000, 469 specimens were collected at depths of between 400 and 620 in off the western coast of Sardinia (Mediterranean Sea). On the basis of cheliped morphology, the males were classified into three demographic categories: immature, adolescent, or adult. In addition, a discriminant function analysis was performed in order to classify the males (post hoc prediction) using the biometric data relating to the four distal segments of the endopod of the right cheliped. For the females, only two demographic categories were detected: juvenile females with flat abdomen and adult females with domed abdomen. Morphological maturity was estimated from the allometric relationships between carapace width and propodus length in males or maximum abdomen width in females. For both sexes, allometric relationships were established in the specimens of each of the demographic categories. Physiological maturity was determined by observing testes or ovary size, colour, morphology, and development. Functional maturity was presumed to be the minimum size at which each sex was morphologically and physiologically able to reproduce. In males, the size at physiological maturity was clearly earlier than the size at morphological maturity, unlike in females where such values were similar
Reproduction strategy of the deep-sea hermit crabs Pagurus alatus and Pagurus excavatus of the Central-Western Mediterranean Sea
No full textSome aspects of the reproductive biology of two hermit crabs Pagurus alatus (Fabricius, 1775) and P. excavatus (Herbst, 1791) were studied. Specimens were collected monthly from April 2000 to March 2001 on the continental shelf and the upper-middle slope off the Southwestern coasts of Sardinia, in the central-western Mediterranean Sea. Crab size (minimum and maximum shield length) was 1.7 and 9.5 mm for 1150 females of P. alatus; 4.0 and 10.4 mm for 347 females of P. excavatus, respectively. Females of P. alatus with ripe ovaries were only found in February-April and ovigerous females were observed throughout the year except in March, with the highest incidence in summer. Females of P. excavatus with fully developed ovaries were collected during all months of the year reaching a peak from April to June. Ovigerous females of P. excavatus occurred throughout the year and the main spawning period occurred in March and April. Fecundity of both species was calculated to assess seasonal variation of reproductive intensity and was positively correlated with the size of the individuals. Monthly fecundity did not reveal significant differences in P. alatus ovigerous females, whereas P. excavatus exhibited significant differences in monthly fecundity depending on the time of year. Difference in fecundity among P. alatus and P. excavatus can be related to the size of the ovigerous females and species of hermit crab, but their different reproductive strategies suggest that they are specifically related to different environmental conditions
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
Introduction and distribution of alien freshwater fishes on the island of Sardinia (Italy): an assessment on the basis of existing data sources
No full textData on the occurrence and distribution of alien freshwater fishes in Sardinia are provided based on historical data and recent reports. A total of 14 introduced fish species are established in Sardinian fresh waters. These species comprise members of the Cyprinidae (carp, Cyprinus carpio; tench, Tinca tinca; goldfish, Carassius auratus; rudd, Scardinius erythrophthalmus; bleak, Alburnus alburnus alborella), Centrarchidae (pumpkinseed, Lepomis gibbosus; largemouth bass, Micropterus salmoides), Salmonidae (rainbow trout, Oncorhynchus mykiss; brown trout, Salmo trutta), Cobitidae (spined loach, Cobitis taenia), Ictaluridae (black bullhead, Ameiurus melas), Percidae (European perch, Perca fluviatilis), and Poeciliidae (mosquitofish, Gambusia holbrooki). The species most recently introduced into Sardinia is the topmouth gudgeon, Pseudorasbora parva (Cyprinidae). The majority of alien fishes documented here match those that have already established self-maintaining populations elsewhere in Mediterranean-type eco-regions. Since the late nineteenth century, fish identified as potential sources of food have been introduced for aquaculture and stock enhancement purposes. Other introductions have subsequently occurred for the purposes of biological control, ornamental use or sport fishing activities. Some species are notably widespread and common (e.g. mosquitofish and tench), whereas the presence of others seems to be more restricted and may still be confined to a few hydrographic regions (e.g. bleak, rudd, pumpkinseed and topmouth gudgeon
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
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