1,721,074 research outputs found
Prface to Eurokarst 2024
No full textIn June 2024, for the first time, the Eurokarst conference, the largest event on karst hydrogeology and carbonate terrains in Europe, was hosted in Rome, Italy. The fourth edition of Eurokarst attracted more than 200 researchers coming from 31 countries distributed in Europe, Africa, North and South America, and Asia.
With the support of the previous hosting organizations, including Universities of Málaga (Spain), Neuchâtel (Switzerland), and Besançon (France), and with the active collaboration of the Karst Commission of the International Association of Hydrogeologists (IAH) and of the IAH Italian Chapter, the goal of the conference was to share and to spread the more recent advances in research on karst and carbonate reservoirs. The response of participants was outstanding, both in terms of participation and of scientific content, helping the karst scientific community to better understand the processes and the human impact on karst aquifers domains all around the world
Variation of male reproductive apparatus in relation to fertilization modalities in the catfish families Auchenipteridae and Callichthyidae (Teleostei: Siluriformes).
No full textTo investigate the relationship between fertilization modalities and the morphology of male
reproductive apparatus, two species of Auchenipteridae, Auchenipterus nuchalis and Tatia
intermedia, and six species of Callichthyidae, Callichthys callichthys, Corydoras aeneus,
Corydoras bondi, Corydoras ehrhardti, Corydoras potaroensis and Hoplosternum littorale were
studied. The species analysed show either internal or external fertilization, the latter including
the so called ‘sperm drinking’ type of mating. An anal fin modified as an intromittent organ,
a pair of seminal vesicles, and the release of sperm in the form of discrete bundles (spermatozeugmata)
characterize the male reproductive apparatus of the internal fertilizer A. nuchalis.
Seminal vesicles are present also in C. aeneus, C. bondi, C. ehrhardti, C. potaroensis and H.
littorale, species performing ‘sperm drinking’ spawning. In contrast, regardless of the family,
species showing the more classic type of external fertilization lack specialized accessory organs.
Where occurring, the major function of seminal vesicles is the secretion of mucins. The role of
these mucosubstances, in relation to spermatozeugmata formation, in internal fertilizers, or the
protection of sperm passing through the female gut, in the ‘sperm-drinking’ species, is discussed.
Variation, between families, in the shape of testis and accessory structures, as well as in the type
of spermatogenesis was found. Neither the reproductive modalities nor the phylogenetic
relationships, however, appear to fully account for these differences
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
Un sistema automatico di misura per la programmazione ed il monitoraggio dell’espansione cutanea.
No full textChanges along the male reproductive axis in response to social context in a gonochoristic gobiid, Zosterisessor ophiocephalus (Teleostei, Gobiidae), with alternative mating tactics
No full textSexual selection has given rise, in several taxa, to intrasexual variation in male phenotype. While evolutionary studies have provided
explanations of the adaptive function of this dramatic male phenotypic diversity, the proximate control of its expression has still to be
completely understood. Several observations, primarily from sex-changing species, indicated a major role of social interactions in
reproductive axis regulation and consequently in the expression of alternative male phenotypes. Here we documented changes along the male
reproductive axis in response to social context in a gonochoristic species, the grass goby Zosterisessor ophiocephalus, where fully functional
alternative male mating tactics appear to be expressed as an ontogenetic gradient. In the grass goby, larger and older males dig a nest and
perform parental care, while smaller males sneak fertilization during territorial male spawning. Territorial males are characterized by a higher
number of gonadotropin-releasing hormone (GnRH) neurons in forebrain preoptic area, smaller testes, larger seminal vesicles, and viscous
ejaculates that last longer and contain fewer sperm than those of sneakers. To experimentally investigate the role of social factors in inducing
changes along the male reproductive axis, sneakers were tested in two different situations: nesting alone or with ripe females. Sneakers that
mated and performed parental care showed dramatic changes in brain, reproductive apparatus morphology, and ejaculate traits. GnRHimmunoreactive
cells in forebrain preoptic area increased in number, reaching values typical of wild-caught parental males. Testes size
decreased while seminal vesicle size increased and ejaculates showed lower sperm densities. These results were discussed within the
framework of the social transduction hypothesis, which predicts that social experience should mediate, through a cascade of internal
processes, shifts between morphs throughout life
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