1,720,963 research outputs found
Schede per una Lista Rossa della Flora vascolare e crittogamica Italiana: Anchusa crispa Viv. subsp. crispa
No full textSeed germination, salt-stress tolerance, and the effect of nitrate on three Tyrrhenian coastal species of the Silene mollissima aggregate (Caryophyllaceae)
Full text linkThe Silene mollissima (L.) Pers. aggregate is part of section Siphonomorpha Otth. and currently comprises 11 narrow endemic species of the Western Mediterranean Basin. Three of these taxa (S. velutina Pourr. ex Loisel, S. ichnusae Brullo, De Marco & De Marco f., and S. badaroi Breistr.) have a distribution range centred in the northern Tyrrhenian area and occurring in coastal habitats. Inter- and intra-specific variability in the responses to light, constant (5–25 °C) and alternating temperatures (25/10 °C), salt (NaCl, 0–600 mmol/L), and levels of nitrate (KNO3, 20 mmol/L) under salt stress, as well as recovery of seed germination were evaluated for these species to more effectively support their in-situ and ex-situ conservation. Our results highlighted that the seeds of these three taxa were nondormant, and that light significantly improved their rate of germination, which was higher (>80%) at low temperatures (5–15 °C) and under the alternating temperature regime (25/10 °C), but decreased significantly at the highest temperature tested (25 °C). Seeds from Silene velutina and S. ichnusae germinated in up to 300 mmol/L NaCl, and S. badaroi germinated in up to 100 mmol/L. For all of the species except S. badaroi, salt did not affect seed viability, and recovery germination did not decrease with increasing salinity and temperature. Interpopulation variability, both in salt tolerance and recovery germination, was detected for S. velutina. The addition of KNO3 did not affect germination or recovery germination under salt conditions. The lack of effect from KNO3 suggests that nutrient availability is not a requirement for seed germination in these species. Our results show that all species experience an optimum period of germination during autumn–winter, which is when water availability is highest and soil salinity levels are minimal because of the Mediterranean rainfalls, but seeds from S. velutina and S. ichnusae will germinate up until spring
Schede per una Lista Rossa della Flora vascolare e crittogamica Italiana: Helicodiceros muscivorus (L.f.) Engl
No full textSchede per una Lista Rossa della Flora Vascolare e Crittogamica Italiana: Silene rosulata Soy.- Will. et Godr. subsp. sanctae-therasiae (Jeanm.) Jeanm
No full text
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
- …
