1,720,956 research outputs found
The genomics of plant response to elevated atmospheric CO2 –elucidating plastic and adaptive mechanisms
No full textThe increase of carbon dioxide concentration ([CO2]) is the main factor in global climate change, and the atmospheric [CO2] has risen from 280 parts per million (ppm) during the pre-industrial period to the most recently estimated figure of 400 ?mol mol-1 due to human activities. The increase of [CO2] could potentially have a morphological, genetic and ecological effect on vegetation. Populus is considered as a model tree to study the autumnal senescence in response to different [CO2] for several reasons. Previous studies have identified elevated [CO2] (e[CO2]) could cause delayed natural autumnal senescence on plants such as poplar and soybean. This report studied two microarrays on two Populus species– Populus. x euramericana and Populus tremuloides grown under ambient and elevated [CO2] (360ppm and 550 560ppm) from POP/EUROFACE and AspenFACE and identified that e[CO2] significantly increased the antioxidative enzyme and products (anthocyanin), thus prevented oxidative stress and therefore caused delayed natural senescence. Further study of e[CO2] effect on an evolutionary level was applied on Plantago lanceolata, a common grass species which has grown in a naturally high-CO2 spring for hundreds of years. The plants from inside and outside of the spring were collected and exposed to either ambient or elevated [CO2] (380ppm and 700ppm) for a seasonal cycle. The morphological study indicated that plant biomass traits were influenced by long term [CO2] (original site), whereas epidermal cells and stomatal traits showed more adaptation to short-term [CO2] change (elevated/ambient [CO2]). The following transcriptome sequencing on the plants from inside and outside spring supported the morphological data and identified an in-sufficient Calvin cycle in spring plants’ response to high [CO2]. However, the significant genetic evolutionary adaption to high [CO2] failed to be detected in this experiment. Furthermore research on the genetic and genomic level was required to understand whether long-term growth in different [CO2] has a selection effect on plants. This will allow the prediction of vegetation behaviour in future atmospheric [CO2]
Plant acclimation and adaptation to a high CO2 world
No full textPlant adaptation to elevated atmospheric carbon dioxide (CO2) is of great interest, as the concentration of this gas in the atmosphere has risen by more than 30% to 388 µmol mol-1 since the industrial revolution. On average there has been a rise of 3 ppm per year. Plant fossil samples suggest that atmospheric CO2 may be acting as a selective agent driving evolution, but limited evidence is available to support this idea that plants subjected to future predicted concentrations of carbon dioxide may adapt. In contrast, much evidence is available on plant acclimation mechanisms and phenotypinc plasticity in future high CO2 concentrations. Studying evolutionary responses to this aspect of environmental change is difficult, but here we use a CO2 spring site where plants have been exposed for multiple generations to concentrations of CO2 predicted for 2050. From this, detailed phenotyping data were collected, including data for stomatal patterning, photosynthetic performance and growth. Considerable evidence exists to show that stomatal numbers have declined across geological time and that this is linked to CO2 concentration, but few CO2-sensitive stomatal patterning genes have ever been identified. When grown under elevated CO2 concentrations P. lanceolata (the narrow leaf plantain), seeds collected from the spring site showed a counter-intuitive increase in stomatal index and density. Here, in this non-model plant we have investigated the gene expression changes underlying this stomatal patterning response to elevated CO2.RNA-Seq allowed for in-depth analysis in P. lanceolata with no previous information required, enabling rapid evaluation of any of novel plant acclimation and adaption mechanisms. Using this approach we have identified a set of novel genes for stomatal patterning in high CO2 and confirmed previously observed acclimation responses
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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