1,721,010 research outputs found
Citometria dei neuroni sopramidollari: il caso di Solea ocellata
No full textNel midollo spinale di Solea ocellata è stata rilevata la presenza di circa 70 neuroni sopramidollari, distribuiti a gruppetti di 2-3-4, nella prima metà del midollo. La forma dei neuroni è variabile, mentre il nucleo è generalmente rotondeggiante o subellittico.Sono presenti numerosi vacuoli citoèplasmatici e capillari endocellulari. I dati citometrici hanno messo in evidenza un'estrema variabilità e un ampio range dimensionale di cellule e nuclei. la determinazione citofluorimetrica su preparati trattati con bromuro d'etidio ha rivelato un contenuto di DNA da 6C a 100C. nel complesso questi risultati indicano che i neuroni sopramidolalri di S. ocellata hanno caratteristiche intermedie tra quelli "allineati" e quelli "clusterizzati"
CYTOMETRY OF SUPRAMEDULLARY NEURONS IN SOLEA OCELLATA
No full textThe supramedullary neurons (SN) are a noradrenergic autonomic system of giant cells, dorsally grouped in a cluster at the boundary between medulla oblongata and spinal cord in some orders of fish, and aligned one by one along the spinal cord in others. Morphology, number and size are peculiar for each species. The axons of SN terminate in the epidermal layer near the mucous glands. Because of the role of aspecific defence of skin mucous cells in fish, the SN system may act in protection from predaction or prevent infection. In this view the study of SNS is very interesting in species fishing of considerable market price.The SN of Solea ocellata, about 70, are distributed in small groups of 2-4 along the cord. The unique nucleolus is intensely basophilic. Vacuoles and endocellular capillaries are present in the cytoplasm, as in SN clustered. The cytometry showed a large variability and a wide range of cells and nuclei size. On the contrary, the nucleoli showed an almost uniform size. The nuclei showed an intense Feulgen-positivity. The cytofluorimetric evaluation revealed a DNA content ranging from 6C in the smaller neurons to 100C in the larger ones, indicating that the peculiar phenomenon of DNA amplification is present also in the SN of S. ocellata, as so far known in those clustered only. Thus, the SN of S. ocellata have characteristics between those clustered and those aligned. The case of S. ocellata suggests that the parting of SN in “aligned” and “clustered” should not be interpreted in absolute way, because this neuronal system shows in different species a wide morphological variability, which reflects functional differences, probably related to environment and behaviour
I peptidi regolativi del tratto digerente nello sviluppo di Dicentrarchus labrax (L.).
No full textIn this study we present tje occurrence of gut regulatory peptides (Substance P, CCK and some POMC-derived molecules) during the first larval phases in Dicentrarchus labrax (Osteichtyes). The immunohistochemical tests were carried out in specimens of 2, 4 and 18 days from hatching
Use of cytometry for the "reproductive model" assessment of the shrimp Palaemon serratus (Pennant, 1777).
No full textThe reproductive biology of the shrimp Palaemon serratus (Crustacea, Decapoda), fisheries resources, has been scarcely studied, especially in the marine habitats of Italian waters. For this purpose, in the present study, monthly samples were taken in brackish waters of the Po River Delta in the North Adriatic Sea. The annual maturative cycle of the ovary was assessed both qualitative, on the basis of histological findings, and quantitative terms, by cytometry. The ovaries feature a proliferative centre from which maturing oocytes branch out in a centrifugal direction. The reproductive period falls between March and June. During the non-reproductive period oocyte diameter ranged from 24 to 153 m, whilst during the reproductive period ranged from 24 to 733 m. The oviposition pattern may be described as “fractioned”, since it is recurrent. In fact, histological and cytometric findings of the Spring catch revealed that the females had both issued eggs that were still attached to the abdomen, as well as oocytes in all stages of vitellogenesis. The size at first maturity was around 51 mm of length.In conclusion, the histo-cytological approach applied throughout the ovary maturation cycle is a good “reproductive model” assessment and an environmental test because the gonadal maturation is closely dependent on enviromental conditions
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
Monitoreo genético no invasivo de una población de nutrias silvestres en los Países Bajos.
No full textAppropriate 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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