1,721,011 research outputs found
Freschi (L.) — Le Haut Adige — Tyrol du Sud : Autonomie et développement.
No full textFreschi (L.) — Le Haut Adige — Tyrol du Sud : Autonomie et développement. . In: Revue de géographie alpine, tome 76, n°3, 1988. pp. 312-314
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
Androgens and the brain
No full textSteroids arriving from the gonads via the circulation modulate brain function, affecting gender differentiation and sexually differentiated behavioral responses, but also the ability of the brain to process, store and retrieve sensory information. Androgens play a pivotal neuroactive role during the "organizational/developmental" phase, mainly in the fetal-neonatal period, when participated to the formation of neuronal circuits, as well as during the aging process when it has been demonstrated to directly affect hippocampal spine synapse density, suggesting a physiopathological role for androgen in the modulation cognitive function and development of neurodegenerative disease. The present short review will focus on the neuroactive effect of androgen with particular regard to the Delta4 and Delta5 androgen replacement therapy
Outside the box: the role of B-BOX proteins (BBX) in tomato fruit ripening
No full textTocopherols, lipid-soluble antioxidants compounds exclusively synthesized in the chloroplast of photosynthetic organisms, are essential for the maintenance of the integrity of thylakoids membranes and, consequently, of photosynthesis. The tocopherol capability of inhibiting the propagation of lipid peroxidation and scavenge oxygen singlet is not only important for the plant physiology, but is also beneficial for human health. Thus, understanding the tocopherol metabolism is interesting for plant breeding with economic and nutritional implications. For tocopherol synthesis, a chromanol ring, produced by shikimic acid pathway, is condensed to phytyl diphosphate (PDP). The latter is originated by de novo synthesis via the methyl erythritol 4-phosphate (MEP) pathway or provided by the recycling of chlorophyll-derived phytol after a two-step phosphorylation sequentially catalysed by PHYTOL KINASE (VTE5) and PHYTYL-PHOSPATE KINASE (VTE6), respectively. During the ripening of tomato fruit, Solanum lycopersicum, chloroplasts turns into chromoplast, what is marked by an intense MEP activity and chlorophyll degradation, turning the tomato an interesting model for the study of tocopherol accumulation. The PDP availability has been identified as a limiting factor for tocopherol synthesis in tomato fruits. While in the green stages of fruit development PDP can be obtained by de novo synthesis via MEP and by the phytol recycling, ripe fruits rely only in the latter pathway, as during ripening the MEP is diverted towards carotenoid accumulation by the downregulation of the GERANYLGERANYL DIPHOSPHATE REDUTASE (SlGGDR). Aiming the improvement of tocopherol accumulation in tomato fruits, two approaches were taken to increase PDP availability: the enhancement of the de novo synthesis and the phytol recycling. For the first, either 1-DEOXY-D-XYLULOSE-5-PHOSPHATE SYNTHASE (DXS), the enzyme involved in the first step of the MEP pathway, or GGDR were targeted; while for the latter, VTE5 or VTE6 were targeted. In all four cases, the ortholog from Arabidopsis thaliana were overexpressed under the control of a fruit specific promoter. The results from the phenotypic chararcterization of the obtained transgenic lines, including the content of chlorophylls, carotenoids and tocopherols, will be presented. The data will bring tools for the development of breeding strategies aiming to enhance the content of an important nutraceutical in tomato edible fruit
Tocopherol metabolism engineering: manipulation of phytol recycling in tomato fruits
No full textTocopherols are liposoluble compounds that are essential for the maintenance of thylakoid membrane integrity due to their high antioxidant capacity. Moreover, these compounds are also important for human health due to their vitamin E activity, particularly α-tocopherol. As only plants can synthesise these metabolites, unravelling the mechanisms that control their accumulation is of interest for biotechnological purposes. In the past few years, it was revealed the importance of the chlorophyll-derived phytol recycling from tocopherol biosynthesis. This process consists in a two-step phosphorylation sequentially catalysed by the PHYTOL KINASE (VTE5) and the PHYTYL-PHOSPATE KINASE (VTE6) rendering phytyl diphosphate. This molecule not only can be used for the synthesis of new chlorophyll molecules, but also for tocopherols, when condensed with homogentic acid. In this context, the tomato (Solanum lycopersicum) fruit is an interesting model for the study of tocopherol manipulation as, along fruit ripening, chlorophyll is massively degraded and tocopherol accumulates. In order to increase the phytol recycling, transgenic tomato plants overexpressing AtVTE5 or AtVTE6 under the control of a fruit-specific promoter were generated. The content of chlorophylls, carotenoids and tocopherols were addressed at the pedicellar (where chloroplasts are fully developed) and at the stylar (which lacks developed chloroplasts) portion of the fruits. While these metabolites in the latter were almost unaffected, when fully developed chloroplast were presented the scenario was different. The pedicellar portion of immature green fruits had more chlorophylls and carotenoids in both overexpressions, however, only in the case of AtVTE6, this led to an increase in tocopherols as fruits ripen. These results hints that increased phytol recycling increases chlorophyll turnover in green fruits, which in turn increased the photosystem-related carotenoids, leading to an increase in the tocopherol content in the edible fruits
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
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