1,720,957 research outputs found
Photosynthetic performance and water use efficiency of the fern Cheilanthes persica
No full textMorphological, anatomical and physiological frond traits of Cheilanthes persica (Bory) Mett. ex Kuhn were studied to analyze its adaptive strategy. Mean frond life span is about 340 d. Mature fronds are characterized by 91 g m(-2) areal dry mass (ADM) and 217 g m(-2) succulence. The reduction of frond water content in July (dehydration phase) caused a 51 % decrease in frond surface area (SA). Fronds were dry in August (desiccation phase); nevertheless, in September they showed an increased SA (rehydration phase). Chlorophyll (Chl) a/b ratio, above 3, and the well developed palisade parenchyma (two layers, total thickness of 103.9 mu m) are typical for sun leaves. Chi and carotenoid contents and net photosynthetic rate (P-N) increased during frond development until the highest values in April-May (maturity phase). When mean air temperature reached 31.3 degrees C, stomatal conductance (g(s)) decreased by 34 % and P-N by 33 %. The high pigment contents can dissipate the excess of radiant energy, particularly under unfavourable conditions, when P-N is low. Rather high P-N was found during the rehydration stage. The pronounced decline of mesophyll activity during the declining phase was confirmed by the lowest P-N
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
Morphological, anatomical and physiological leaf trait plasticity of Sesleria nitida (Poaceae) in open vs shaded conditions
No full textAn expression of plants response to light availability is their shade tolerance which refers to the capacity of a given plant to tolerate low light levels. Survival in a shaded environment can determine phenotypic consequences at morphological and/or physiological levels and such changes may be crucial to survive in heterogeneous and variable conditions. However, the potential plastic response of a given plant trait may be large but the observed plasticity may be lowered by resource limitations or environmental stress factors. In this context, the aim of this research was to analyze morphological, anatomical and physiological leaf traits variations of Sesleria nitida Ten, growing in different light conditions. In particular, plants growing in open (PO) and shade (PU) conditions were analyzed. The results show a 35% higher specific leaf area (SLA) in PU than in PO due to a 94% larger leaf area (LA). The higher height and width of the central and the major lateral vascular bundle in PO than in PU contribute to a higher net photosynthesis (P-N) in sun than in shade conditions. Moreover, the 33% higher ratio between respiration (R-D) and PN (R-D/P-N) in PU than in PO highlights the greater proportion of the carbon consumed by R-D in the shade population requiring a greater metabolic effort for growth and maintenance. S. nitida in the shaded environment might be favored by the soil pH being a neutro-basophilous species and the larger soil water content (SWC) and mineral content contributing to maintain a positive carbon balance in this limiting condition. The plasticity analysis for open vs. the understory plants (mean plasticity index = 0.32) highlights the leaf trait variations useful to maintain a positive carbon balance where light availability is the main limiting factor. Knowledge of the capacity of S. nitida to first colonize and then modify its phenotype in response to the shade condition can contribute to a better understanding of its ecology
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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