1,721,016 research outputs found
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
Studio dei sistemi di captazione del ferro in germi del genere Vibrio.
No full textVibrio genus includes bacterial species pathological both for different acquatic organisms and for man, and considering their wide diffusion in acquatic environment, the study of such germs concerns the interactions between them and environment, considered as abiotic elements, i.e. water, and as biotic resources like natural or breeding species, as well as man. The results of interactions germs-environment can be identified in the result of competition for micro- and macro-nourishments, in wich iron element becomes very important. The present research deals with the characterization of isolated Vibrio genus starting from Adriatic sea fish samples, and successive evidence of their iron trasmission systems. 64 bacterial strains have been isolated from seventy fish products samples including cods, mullets, soles, prawns, crabs and clams. The isolated ones have been characterized in a biochemistry way; then 22 have been considered bacteriums belonging to Vibrio genus (n°3 V. cholerae, n°9 V. alginolyticus and n°10 V. parahaemolyticus). These have been tested according to the resistence to an antibiotics range and to the haemolytic power by Kanagawa test made on Wagatsuma agar. Moreover on the examinated bacteriums have been valued the ability to produce siderophores, compounds with low molecular weight, able to bind iron and to represent growth, germination or virulence factors. The production of siderophores has been noticed by bacteriums growth on CAS agar, continuing then in their qualitative valuation by spectrophotometry assay. Moreover, the study of induction of Iron-Regulated Outer Membrane Proteins has been carried out; three different bacterial strains, belonging Vibrio genus, have been cultivated in iron-deficient and iron-enrichment conditions, through M9 Minimal Medium (MM9) with addition of EDDA and ferric chloride, respectively. The outer membrane proteins extracted have been separated in SDS-PAGE and strains grown in iron-deficient media have showed the induction of proteins of 78 kDa for V. alginolyticus and V. parahaemolyticus,77 kDa for V. cholerae. This research represents, relatively to Vibrio genus, a possible starting point in the approach of themes concerning the behaviour of microbic population and the pathogenesis of infections that could negatively affect fish productions and man’s health for fish consumption and for acquarium fish possible zoonosis risks. [...
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
Livelli di contaminazione da policlorobifenili in specie ittiche del mare adriatico: indagine preliminare
No full textMUSSELS STRESS MARKERS: USEFUL TOOLS TO MONITORING THE PRODUCT QUALITY?
No full textThe stress represents a disruption of the physiological steady state of the organism, known as homeostasis, and severalmorphological and physiological markers have been investigated as useful tools to measuring the effects of a variouskind of stressors on the homeostasis condition. The marine bivalve molluscs play a key role as sentinel organisms in theenvironmental monitoring for their sedentary and filter-feeding characteristics. In addition, they have an important role aseconomic source in many countries and in the widespread food consumption.The molluscs can suffer the environmental stress due to the growing areas conditions (temperature, dissolved oxygen,salinity, pollutants, etc.) and the homeostasis disruption could take to deleterious effects for natural beds or shellfishfarming, in terms of natural mortality or increased susceptibility to pathogens.Furthermore, bearing in mind the molluscs intended for immediate human consumption must comply with the possessionof visual characteristics associated with freshness and viability, stress conditions linked to the successive processing stageslocated before the placing on the market (harvesting, transportation, relaying, depuration, handling, storage, etc.) couldstraight affect the product quality.The mussels play an important economic role in the worldwide shellfish farming and various morphological or functionalmarkers have been proposed for monitoring the negative impact of the stressors on the mussel homeostasis.In particular, the invertebrate immune system represents a suitable model for understanding the stress effects. In fact, thestress can modulate the properties of the phagocytic cells, known as hemocytes, in terms of pseudopodia emission andreactive oxygen species (ROS) synthesis. In this sense, the cell behaviour computerized analysis, the flow cytometry andspecific micromethod assays could represent innovative methods for measuring the hemocyte spreading, phagocytosisactivities and their modulation linked to the stress.Furthermore, among the several proteins implied in the assessment of the stress response, the heat shock proteins (HSPs70 kDa) represent a class of highly conserved proteins and various field and experimental studies have confirmed theirinduced protective role following exposure to different kind of stressors. The possibility to develop genetic probes, specificmonoclonal antibodies and useful tools starting from the purified protein could supply more accurate information aboutthe stress response.In conclusion, the stress parameters in bivalve molluscs could represent useful tools applied not only to the environmentalmonitoring, but also in the management of the shellfish farming and food quality assessment.[...
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