1,721,303 research outputs found
Storie della modernità. Spazi mediterranei e prospettive globali. Studi in onore di Mirella Vera Mafrici
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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
Cambiando pelle
No full textIntroduzione a un volume dedicato all'analisi della rinascita come tema letterario nella tradizione italiana dalle origini al Novecento
ADULT SOD1 G93R ZEBRAFISH MODEL DEVELOPS HALLMARK FEATURES OF ALS AND DISPLAYS NEUROMUSCULAR JUNCTIONS DEFECTS AND SPINAL NEURONS HYPEREXCITABILITY AT EARLY DEVELOPMENTAL STAGES
Full text linkAmyotrophic Lateral Sclerosis (ALS) is an adult-onset neurodegenerative disease characterized by selective and progressive loss of motor neurons in the spinal cord, brain stem and motor cortex. Approximately 12% of familial and 1% of sporadic cases of ALS are associated to mutations in the gene coding for the antioxidant enzyme Cu-Zn Superoxide Dismutase type 1 (SOD1).
Zebrafish is emerging as a powerful experimental model for the study of disorders affecting the nervous system and here we characterized the disease phenotype in adult zebrafish overexpressing the Sod1 ALS-linked mutation G93R (mSod1) and the wild-type Sod1 (wtSod1).
Adult zebrafish expressing mutant Sod1 develop most of the main pathological features occurring in ALS: locomotor impairments, motor neurons degeneration, spinal cord and muscle atrophy, neuromuscular junctions loss, astrogliosis and inflammation. Interestingly, as it was reported in mice models of the disease, also in this model the overexpression of the wild-type form of Sod1 is associated to the development of mild alterations.
Having completed the characterization of the pathological phenotype in the adult, we searched for precocious ALS hallmarks in zebrafish embryos and larvae. The optical transparency of zebrafish at early developmental stages allowed us to perform whole-mount fluorescence staining from which we studied the effects of the overexpression of wild-type or mutant Sod1 on spinal motor neurons development and neuromuscular junctions maturation. Mutant zebrafish embryos display precocious motor nerves branching defects while larvae present neuromuscular junctions maturation impairments and muscle fibers atrophy. The expression of mutant Sod1 is associated to precocious behavioral alterations in spontaneous tail coilings at 20 hpf, in touched evoked tail coiling responses at 48 hpf and in burst swimming responses at 96 hpf.
In Sod1 G93R expressing embryos we detected spinal neurons hyperexcitability associated to the increased activity of the persistent sodium current INaP, and by the administration of riluzole, directly into the embryo water, we managed to pharmacologically modulate the spinal neurons electrical activity, the behavioral phenotype and the motor axons length.
These results are extremely relevant since several studies demonstrated that ALS patients exhibit cortical hyperexcitability before any clinical sign of ALS and electrophysiological experiments performed in cultured mice embryonic and neonatal dissociated spinal motor neurons expressing mutant SOD1 G93A demonstrated neuronal hyperexcitability associated to the increased activity of the persistent sodium current INaP.
This work demonstrates that the Sod1 G93R zebrafish model not only represents a valuable complement to other animal model for the study of ALS but also that it is a powerful model on its own to investigate ALS mainly thanks to the possibility to study locomotor circuits and potential pathogenetic mechanisms occurring at the very early stages of disease pathogenesis
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
BIORES - Resistenza e resilienza della biodiversità costiera agli effetti sinergici di cambiamenti ambientali su scala locale e globale
No full textScopo principale del presente progetto è lo studio integrato dell'effetto del disturbo tra scale (globale vs locale) e sistemi (marini vs terrestri). Affronteremo questa
tematica svolgendo un esperimento in ambienti di duna costiera con lo stesso approccio logico ed un disegno sperimentale analogo all'esperimento nella fascia
subtidale superficiale illustrato nel modulo B dell'unità di Pisa. L'esperimento analizzerà se i popolamenti vegetali costieri terrestri rispondano in maniera analoga ai
popolamenti macroalgali marini quando sottoposti a fattori di disturbo ambientali. Verranno manipolati due fattori considerati importanti per l'ecologia delle specie
vegetali delle dune costiere, l'aerosol marino (spettro "rosso" di variabilità spaziale) ed il pascolamento di erbivori (spettro "bianco" di variabilità spaziale).
L'esperimento verrà realizzato in tre siti (Foce Bevano, Marina di Pisa, e Carovigno) in stretta collaborazione tra le tre unità di ricerca coordinate dall'Unità di
Ravenna. Il raffronto tra i risultati dei due esperimenti permetterà di confrontare la resistenza e resilienza di due sistemi all'interfaccia tra mare e terra all'effetto
sinergico dei fattori di stress globali e locali, e di identificare le relazioni tra scale di impatto e risposte in ciascun sistema
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