1,720,979 research outputs found
Analisi cromatica e analisi all'infrarosso: tecniche a confronto per la documentazione, il monitoraggio e la diagnosi del patrimonio artistico
No full textDoes Hermetia illucens recognize sibling mates to avoid inbreeding depression?
No full textManagement of genetic diversity in Hermetia illucens L. (Diptera: Stratiomyidae) commercial colonies is a key problem. Inbreeding depression can affect the maintenance and sustainability of insect farming, in particular small-scale mass-rearing, by reducing population fitness or causing colony collapse. In animals, kin recognition could play a role avoiding inbreeding and mating with sibling. To determine inbreeding impact in a H. illucens laboratory strain, the courtship and mating behaviour occurring between unrelated or full-sibling mates were compared in controlled crosses. Furthermore, selected lifetime parameters, including egg laying and fertility, developmental time, total fecundity, and sex ratio, were compared. Inbreeding depression can be observed by second generation of full-sibling mating, with a severe reduction of produced progeny (emerged adults per female, No-Sib: 234.9 ± 38.0 vs. Sib2: 64.3 ± 16.7). No differences attributable to kin recognition were noted in the pre-copula and post-copula behavioural sequences. However, copulation was prolonged in inbred mates (No-Sib:
35.5 ± 2.8 min vs. Sib2: 52.2 ± 6.4 min), probably due to the physiological characteristics of the mates. Nevertheless, a valuable restoring impact of backcross on several life-time parameters was also observed, mitigating the impact of inbreeding depression.
This research provides valuable information about inbreeding and mate selection to avoid population depression in H. illucens. Further studies are needed to investigate the occurrence of other selection mechanisms in this species, as well as the possible impact of outbreeding on population fitness
Interaction between ants and the Mediterranean fruit fly: New insights for biological control
No full textDuring recent years, the positive role of ants as biological control agents in agro-ecosystems has gained growing interest. We investigated the predatory relationship between Ceratitis capitata (Wiedemann) and the ant Tapinoma nigerrimum (Nylander), commonly widespread in the Mediterranean area. Additionally we investigated some bio-ethological aspects of C. capitata larvae that could be relevant timing factors for predation. Field observations highlighted that C. capitata larvae were preyed on by ants, and laboratory assays suggested that movement of medfly larvae, as well as olfactory cues, affected prey location by T. nigerrimum. Further observations on the circadian activity of C. capitata suggest that mature larvae leave the fruit to pupate in the soil mainly in the early morning, and they can bury faster in moistened soil. These ecological aspects are discussed in the context of sustainable agriculture
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
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
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