1,720,955 research outputs found
Impact of recreational harvesting on assemblages in artificial rocky habitats
Get PDFMan-made structures have become ubiquitous features of coastal landscapes. These artificial habitats are popular recreation sites. Patterns and effects of recreational activities were investigated from 1999 to 2004 on coastal structures along 40 km of shoreline in the Emilia Romagna region (North Adriatic Sea, Italy). Four studies estimated the magnitude and frequency of exploitation by people, and established how human exploitation varied in space and time. A manipulative experiment involving the removal of mussels, mimicking the impact of human harvesting, was carried out to identify the effects of extensive mussel exploitation. Recreational exploitation was a major recurrent disturbance. Hundreds of people visited defence structures for recreational fishing and to harvest a variety of invertebrates to be used primarily as food. Human exploitation was most intense during the spring and summer but relatively unpredictable at scales of days and hours. Exploitation was homogeneous among..
Osservazioni sulla parassitofauna del tonno rosso (Thunnus thynnus).
No full textIl grande interesse commerciale rivestito dal tonno rosso (Thunnus thynnus) ha spinto negli
ultimi anni ad intraprendere in diverse aree del bacino mediterraneo attività di acquacoltura
volte all'ingrasso di soggetti selvatici in gabbie galleggianti. Lo sfruttamento zootecnico di
questa specie deve necessariamente essere corredato da un approfondimento delle conoscenze
sulle patologie che possono interferire negativamente con il successo produttivo e
parallelamente con la qualità e la salubrità del prodotto finale.
Nel corso del 2004 si è condotta un'indagine parassitologia su 55 soggetti di tonno rosso, di
cui 20 selvatici catturati in areali di pesca della Sicilia occidentale e 35 provenienti da
allevamenti in gabbia siti in Sicilia occidentale e nell'alto Adriatico. Su tutti i soggetti, di peso
compreso tra 2,6 e 120 kg, è stato possibile esaminare il pacchetto viscerale e le branchie.
L‟esame parassitologico è stato condotto a fresco mediante osservazione macroscopica degli
organi ed esame microscopico di raschiati e porzioni di tessuti. Su alcuni organi è stato inoltre
condotto esame istologico previa fissazione in formalina tamponata al 10%. I soggetti
selvatici sono risultati sempre negativi all'esame parassitologico, così come i soggetti
provenienti dall'allevamento della Sicilia occidentale. Nei soggetti provenienti
dall'allevamento dell‟alto Adriatico sono stati invece osservati diversi reperti parassitari. In
particolare a livello branchiale si sono riscontrate cisti parassitarie contenenti trematodi
digenei della famiglia Didymozoidae, morfologicamente riferibili al genere Didymocystis, già
descritto sia in tonni selvatici che d‟allevamento (Munday et al., 2003; Mladineo e Tudor,
2004). L'esame microscopico dei filamenti branchiali ha inoltre permesso di evidenziare,
soprattutto all‟interno dei capillari branchiali, numerose uova di trematodi digenei
Sanguinicolidae che, sulla base delle misure e della morfologia, sono state riferite al genere
Cardicola, potenzialmente patogeno per l'ospite in condizioni stressogene. L'esame
istologico ha confermato la presenza di queste uova all'interno dei vasi branchiali ed ha
inoltre rilevato la presenza di diverse cisti parassitarie di digenei Didymozoidae nella parete
dell'intestino. Istologicamente si sono inoltre reperiti, all'interno dei vasi epatici di un
esemplare, stadi di sviluppo ematici di parassiti Myxozoa, sebbene l'esame parassitologico a
fresco non avesse evidenziato spore di mixosporidi a livello degli organi esaminati. Infine, in
un unico soggetto sono state reperite nello spessore del mesentere larve di nematodi
Anisakidae, identificate morfologicamente come larve al terzo stadio di Anisakis sp., genere
parassitario potenzialmente patogeno per l'uomo in seguito ad ingestione di prodotti ittici
crudi o poco cotti. I risultati di questa ricerca hanno evidenziato l'assenza di agenti parassitari
nei tonni selvatici ed ingrassati negli areali della Sicilia occidentale, perlomeno per quanto
concerne gli organi esaminati, ed una maggiore diffusione di diverse specie di parassiti in
quelli allevati nel nord Adriatico, ad indice del ruolo fondamentale dell'ecosistema marino
nella dinamica delle infezioni sostenute da parassiti eteroxeni come quelli da noi riscontrati
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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