1,721,119 research outputs found
Role of the circadian clock in fine-tuning the process of leaf senescence in plants
Full text linkLeaf senescence is a developmental process and a critical evolutionary strategy for fitness in plants, involving highly organized regulatory mechanisms. Many environmental signals as well as internal developmental aging trigger leaf senescence. Circadian clocks provide timing information for the adaptation of organisms to changing environmental conditions via dynamic metabolic and physiological regulatory networks. Interactions between aging and circadian clock have been well characterized in animals. In plants, recent studies reveal similar interactions between leaf
senescence and circadian clock, supporting the evolutionary conservation of these interactions in both animal and plant kingdoms. In this review, we discuss the major clock components and senescence regulators that connect these two regulatory mechanisms, and the significance of this relationship in the plant life history. © 2019 KeAi Communications Co
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
Combinatory actions of CP29 phosphorylation by STN7 and stability regulate leaf age-dependent disassembly of photosynthetic complexes
Full text link© 2020, The Author(s). A predominant physiological change that occurs during leaf senescence is a decrease in photosynthetic
efciency. An optimal organization of photosynthesis complexes in plant leaves is critical for efcient
photosynthesis. However, molecular mechanisms for regulating photosynthesis complexes during leaf
senescence remain largely unknown. Here we tracked photosynthesis complexes alterations during
leaf senescence in Arabidopsis thaliana. Grana stack is signifcantly thickened and photosynthesis
complexes were disassembled in senescing leaves. Defects in STN7 and CP29 led to an altered
chloroplast ultrastructure and a malformation of photosynthesis complex organization in stroma
lamella. Both CP29 phosphorylation by STN7 and CP29 fragmentation are highly associated with the
photosynthesis complex disassembly. In turn, CP29 functions as a molecular glue to facilitate protein
complex formation leading phosphorylation cascade and to maintain photosynthetic efciency during
leaf senescence. These data suggest a novel molecular mechanism to modulate leaf senescence via
CP29 phosphorylation and fragmentation, serving as an efcient strategy to control photosynthesis
complexes.11Nsciescopu
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
Subcellular Localization of GIGANTEA Regulates the Timing of Leaf Senescence and Flowering in Arabidopsis
Full text link© 2020 Kim et al. Plants undergo several important developmental transitions including flowering and senescence during their life cycle. Timing these transitions according to the environmental conditions increases plant fitness and productivity. The circadian clock senses various environmental cycles, including photoperiod, and synchronizes plant physiological processes to maximize plant fitness. Here, we propose that the cellular localization of GIGANTEA (GI), a key clock component, regulates leaf senescence and flowering in Arabidopsis thaliana. We show that GI, which connects the circadian clock with photoperiod-regulated flowering, induces leaf senescence depending on its subcellular localization. Overexpression of GI in the gi mutant rescued its delayed senescence phenotype but only when the GI protein was targeted to the nucleus, not when it was targeted to the cytosol. In the nucleus, EARLY FLOWERING 4 (ELF4) inhibited the binding of GI to ORESARA 1 (ORE1) promoter to regulate leaf senescence. GI also positively regulated the day-peak of ORE1 expression. These results indicate that like flowering, leaf senescence is also controlled by the location of GI in the cell. Taken together, our results suggest that ELF4 and GI act together to control flowering and senescence in Arabidopsis.11Nsciescopu
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