1,720,992 research outputs found
Octopus vulgaris (Mollusca, Cephalopoda) as a model in behavioral pharmacology: A test of handling effects
No full textDespite the great interest of Cephalopods in learning studies, behavioral pharmacological experiments using these animals are scanty. The purpose of this study was to find an appropriate method of injection of substances for studying their effects on the behavior of octopuses. We injected into the branchial heart a known volume of seawater to test the effect of cold anaesthesia and of different types of manipulation on the predatory performance of Octopus vulgaris. An injection procedure that is simple, reliable, and does not require anaesthesia is proposed. The article also addresses ethical and manipulation requirements of modem behavioral pharmacology
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
Simultaneous hydrolysis of tri and tetrasaccharides by industrial mixtures of glucoamylase and alpha-amylase: kinetics and thermodynamics
No full textThe present paper deals with the study of the kinetics and thermodynamics of batch enzymic hydrolysis of multisubstrate media in the presence of more than one glucanase
In vivo investigation of the arm nerve cord morphology of the Octopus vulgaris, using ultrasound techniques
No full textVariations 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
Behavioural and immunological responses to an immune-challenge in Octopus vulgaris
No full textBehavioural and immunological changes consequent to stress and infection are largely unexplored in cephalopods, despite the wide employment of species such as Octopus vulgaris in studies that require their manipulation and prolonged maintenance in captivity. Here we explore O. vulgaris behavioural and immunological (i.e. haemocyte number and serumlysozyme activity) responses to an in vivo immune challengewith Escherichia coli lipopolysaccharides (LPS). Behavioural changes of immune-treated and sham-injected animals were observed in both sightallowed and isolated conditions, i.e. visually interacting or not with a conspecific. Immune stimulation primarily caused a significant increase in the number of circulating haemocytes 4 h after the treatment, while serum lysozyme activity showed a less clear response. However, the effect of LPS on the circulating haemocytes begins to vanish 24 h after injection. Our observations indicate a significant change in behaviour consequent to LPS administration, with treated octopuses exhibiting a decrease of general activity pattern when kept in the isolated condition. A similar decrease was not observed in the sight-allowed condition, where we noticed a specific significant reduction only in the time spent to visually interact with the conspecific. Overall, significant, but lower, behavioural and immunological effects of injection were detected also in sham-injected animals, suggesting a non-trivial susceptibility to manipulation and haemolymph sampling. Our results gain importance in light of changes of the regulations for the use of cephalopods in scientific procedures that call for the prompt development of guidelines, covering many aspects of cephalopod provision, maintenance and welfare
Noninvasive study of the Octopus vulgaris arm morphology using ultrasound
No full textOctopus arms are extremely dexterous structures. The special arrangements of the muscular fibers and nerve cord allow a rich variety of complex and fine movements under neural control. The arm structure has been historically investigated using traditional comparative morphological ex-vivo analysis. Here we employed ultrasound imaging, for the first time, to explore in vivo the arms of the cephalopod mollusc Octopus vulgaris.
Sonographic examination (linear transducer, 18 MHz) was carried out in anesthetized animals along the three anatomical planes: transversal, sagittal and horizontal. Images of the arm were comparable to the corresponding histological sections. We were able, in a non-invasive way, to measure dimensions of the arm and its internal structures such as muscle bundles and neural components. In addition, we evaluated echo intensity signals as an expression of the difference in the muscular organization of the tissues considered (i.e. transverse versus longitudinal muscles), 38 finding different reflectivity based on different arrangement of fibers and their intimate relationship with other tissues.
In contrast to classical preparative procedures, ultrasound imaging can provide rapid, destruction-free access to morphological data from numerous specimens, thus extending the range of techniques available for comparative studies of invertebrate morphology
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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