1,720,954 research outputs found
New records of sponges associated with siliquariid molluscs from the Indo-Pacific Ocean
No full textSiliquariidae family represents a small group of Caenogastropoda molluscs that can be found fixed on hard substrates or, as in the genus Tenagodus Guettard, 1770, obligatorily dwelling within the body of sponges of the class Demospongiae.
Despite this obligatory interaction, references to symbiosis in literature are relatively scarce, due to the rarity and elusiveness of these partnerships. The association does not appear to be strictly species-specific, although only a limited number of sponge families are known to host these molluscs.
Pansini et al. (1999) and Bieler (2004) are the only two authors who accurately described the details of this symbiosis. Both highlighted the perfect connection between the sponge’s aquiferous system and the filter-feeding apparatus of Siliquariids. This allows the mollusc to convey and discharge self-drained water into the sponge incurrent canal system.
The aim of this work was to investigate the association, with a particular focus on the involved sponge's characterization.
A total of 29 samples from the Philippines and New Caledonia, collected between 1978 and 1993 at depths ranging from 90 m to 550 m, were analyzed. Sponge morphological characterization was carried out using the standard method.
We reported the presence of Demospongiae belonging to 5 genera: Topsentia Berg, 1899; Spongosorites Topsent, 1896; Erylus Gray, 1867; Penares Gray, 1867 and Discodermia du Bocage, 1869. These genera align with those already reported by Pansini, while Bieler also mentions Siliquariaspongia Hoshino, 1981 and Thrombus Sollas, 1886, not present in our samples. Such sponges are mainly encrusting or with a massive habit, nearly completely covering the shell. As far as porifera are concerned, symbiosis is not obligatory and, in fact, all sponge species involved can also lead to a free-living existence.
Additionally, a literature analysis suggests that the growth form and color of sponges may be strongly influenced by the presence of Siliquariids
Characterization of Iophon spp. (Porifera, Demospongiae) in association with the brittle stars genus Ophioplinthus (Echinodermata, Ophiuroidea) in the Southern Ocean
No full textSponges represent one of the most important components of the Antarctic zoobenthos, with over 350 known species found on hard and soft substrata, where they increase habitat heterogeneity. Due to hard substrates scarcity in the Antarctic sea bottom, sponges often show peculiar morpho-functional adaptations required to thrive on soft bottoms or to colonize biotic secondary substrates. In these cases, the associations are referred to as ectosymbioses. Symbiotic interactions represent important ecological and evolutionary drivers, often promoting speciation through host shift. Extensive investigations into benthic biodiversity in the Southern Ocean and the ecological role of symbiotic interactions has been recently re-evaluated.
In this context, particularly intriguing is the ectosymbiontic relationships established between brittle-stars of the genus Ophioplinthus Lyman, 1878 and the demosponge genus Iophon Gray, 1867. Even though this interaction is widely reported in the Antarctic scientific literature, detailed information regarding the partners is still limited. In this work we analysed the samples available at the Italian National Antarctic Museum (MNA, Section of Genoa) to classify the partners of the association at the finest possible level. Thanks to these new materials we report the first record of I. flabellodigitatum Kirkpatrick, 1907 on O. brevirima (Mortensen, 1936) and of I. unicorne Topsent, 1907 on O. gelida (Koehler, 1901). Out of the 166 Ophioplinthus specimens examined in this work, the significant proportion of 57.8% were found to be engaged in symbiotic associations, highlighting the importance of this interactions within the Antarctic brittle star population. In the specimens studied, the presence of Iophon has different degrees of development but numerous specimens of O. gelida did not exhibit this association, while all the O. brevirima specimens present the symbiosis. Our analysis also reported a difference between the external morphology of the two Iophon sponge compared to the original description by Kirkpatrick of 1907
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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