1,720,966 research outputs found
Water flow in the roots of crop species: The influence of root structure, aquaporin activity, and waterlogging
No full textCopyright © 2007 Elsevier Inc. All rights reserved.The hydraulic properties of plant roots depend on the morphology and anatomy of the root system, the length of the absorbing region and the influence of aquaporins (AQPs). These features change during development and in response to environmental stimuli, and alter the hydraulic conductivity of the root system (Lpr). AQPs are proteins that form water selective channels to facilitate water flow across membranes. A large proportion of AQP isoforms are predominantly expressed in roots and their localization indicates a putative role in the transport of water across the root. AQP activity can finely regulate the rate of water flow across the root by changes in abundance and opening/closing the water channels. Since water will flow by the pathway of least resistance, AQPs will only influence radial water flow if the hydraulic conductivity of the apoplast is relatively less than that of the cell-to-cell pathway. There is growing evidence that AQPs influence water flow through the roots of some, but not all, species. Waterlogging is a significant environmental constraint to crop growth, but its influence on Lpr is poorly understood. Depending on the tolerance of the species, waterlogging through oxygen deficiency reduces root growth and tends to reduce Lpr. Oxygen deficiency can directly or indirectly close AQPs or alter their abundance. Changes in AQP activity may be the key component which ultimately influences water transport through waterlogged roots. © 2007 Elsevier Inc. All rights reserved.H. Bramley, D.W. Turner, S.D. Tyerman and N.C. Turne
Differential fruitset between grapevine cultivars is related to differences in pollen viability and amine concentration in flowers
No full textVersion of Record online: 12 NOV 2015Background and Aims: Reproductive capacity among grapevine cultivars varies considerably and impacts yield. Bioactive amines are reported to be involved in many aspects of plant reproductive physiology. We aimed to examine the association between the reproductive performance of cultivars and the concentration of amines in the reproductive organs. Methods and Results: The reproductive performance of Shiraz, Merlot and Cabernet Sauvignon was assessed by determining fruitset, coulure index, millerandage index, pollen tube growth and stigma receptivity. Endogenous concentration of amines in flowers and berries was measured. Poor reproductive performance exhibited by Cabernet Sauvignon and Merlot compared with that of Shiraz was correlated with poor pollen viability. Amine profiles in the flowers and berries varied significantly among cultivars. A significantly higher concentration of diaminopropane was found in Merlot and Cabernet Sauvignon and correlated with a higher proportion of underdeveloped berries. An aromatic amine phenylethylamine was found to be the major free amine in the flowers of Merlot, a cultivar susceptible to poor fruitset. Conclusion: Variable reproductive performance exhibited by grapevine cultivars is related to differences in pollen viability and amine concentration in the reproductive organs. Significance of the Study: A better understanding of the association between reproductive performance and amines in the reproductive organs of grapevines has been achieved.T. Baby, M. Gilliham, S.D. Tyerman and C. Collin
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
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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