1,721,243 research outputs found
GILL MORPHOLOGY AND ATPASE ACTIVITY IN THE GOLDFISH CARASSIUS-CARASSIUS VAR AURATUS EXPOSED TO EXPERIMENTAL LEAD-INTOXICATION
No full textThe effect of acute lead intoxication (5 mg l-1) on the structure and function of the gills in Carassius carassius var. auratus was studied. The gills absorbed Pb very quickly and the storage increased progressively in the longest treated specimens. Light and electron microscopy observations on gill filaments from unexposed fish showed in organization similar to that described for other teleosteans. Gill histological and cytological alterations induced by lead were detected after 24 h of treatment and became more evident after 48 h. The salient changes were the following: 1) free parts of secondary lamellae increased in length and had irregular outlines; 2) an increased number of mucocytes, prevalently distributed over the superficial layer of the primary epithelium; 3) chloride and epithelial cell ultrastructure were particularly damaged; the degenerating chloride cells were more numerous; 4) K+-NPPase activity was not particularly affected; on the contrary, Ca2+-ATPase increased particularly in chloride cells
Realizzazione e prova di celle complete da laboratorio. Definizione del design di cella
Full text linkIl presente rapporto illustra il design di cella sviluppato per la realizzazione (in scala di laboratorio) di celle complete litio-ione per applicazioni alle reti elettriche. Nel corso delle attività svolte nel periodo ottobre 2011 – settembre 2012 sono stati utilizzati due differenti design di cella. Il primo, denominato “tipo T”, è stato sviluppato nel precedente periodo di attività (ottobre 2010 - settembre 2011) ed è stato impiegato per la caratterizzazione elettrochimica dei materiali catodici e anodici (in elettrolita organico convenzionale) sviluppati e selezionati (nel periodo di attività ottobre 2011 - settembre 2012) nel corso delle attività relative agli Obiettivi A e B.
Il secondo design di cella è stato appositamente sviluppato per celle complete litio-ione che utilizzano un elettrolita poco volatile ed ininfiammabile (data la presenza di liquidi ionici). Quest’ultima tipologia ha permesso la realizzazione di celle sottili aventi spessore totale attorno 200 micrometri (inclusi i portacorrente elettrodici). Le celle sono alloggiate in contenitori “soffici” (denominati coffee-bag), impermeabili ad acqua ed aria e aventi bassa densità e, successivamente, sigillate sotto vuoto. La presente tipologia presenta numerosi vantaggi: i) elevata sicurezza (ininfiammabilità) della cella; ii) assenza di ossigeno (entro la cella) che, come noto, promuove fenomeni di riduzione dell’elettrolita; iii) nessuna possibilità di contaminazione con l’esterno; iv) adattabilità a diverse geometrie di cella; v) robustezza e flessibilità meccanica della cella; vi) aumento energia specifica della batteria dovuto alla diminuzione in peso del contenitore. I risultati ottenuti sono riferiti al periodo di attività ottobre 2011–settembre 2012
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
Radiosurgical treatment of cavernous sinus meningiomas: experience with 122 treated patients
No full textOBJECTIVE: To evaluate the efficacy of gamma knife (GK) radiosurgery, in terms of neurological improvement and tumor growth control (TGC), for a large series of patients with cavernous sinus meningiomas. METHODS: Between February 1993 and January 2002, 156 patients with cavernous sinus meningiomas (35 male and 121 female patients; mean age, 56.1 yr) were treated with GK radiosurgery in our department. GK radiosurgery was used as a first-choice treatment for 75 of 156 patients and as postoperative adjuvant therapy for 81 of 156 patients (all with Grade I meningiomas). Eligibility criteria for radiosurgery were as follows: symptomatic meningiomas and/or documented tumor progression on magnetic resonance imaging scans, conditions of high operative risk, patient refusal of microsurgery or reoperation, tumor volume of 4 yr), GK radiosurgery seems to be both safe (permanent morbidity rate, 1%) and effective (97% neurological improvement/stability, 97.5% overall TGC, and 96.5% actuarial TGC at 5 yr). GK radiosurgery might be considered a first-choice treatment for selected patients with cavernous sinus meningiomas
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