1,720,996 research outputs found
Mathy P. (1997). Donner du sens au cours de sciences. Bruxelles-Paris, De Boeck Université
No full textDarley Bernard. Mathy P. (1997). Donner du sens au cours de sciences. Bruxelles-Paris, De Boeck Université. In: Didaskalia, n°14, 1999. Enseigner les sciences et les techniques à l'université. pp. 154-156
Secondary effects of photochemical oxidants on cereals: alterations in susceptibility to fungal leaf diseases
No full textIn a nine-day fumigation experiment with 60–80 ppb ozone and 6–8 ppb PAN (peroxyacetyl-nitrate) predisposition of wheat and barley towards necrotrophic leaf pathogens was enhanced although leaves were not visibly injured by the treatment. Particularly, spot blotch (Drechslera sorokiniana) and tan spot (D. tritici-repentis) on wheat and spot blotch on barley were favoured by either of the two pollutants. The pollutant mixture exerted a highly synergistic action on plant susceptibility. In another experiment, wheat leaf attack by Septoria nodorum was highly correlated with increasing levels of ozone (0, 60, 90 and 120 ppb; 7 days; 7 h per day), applied before inoculation. Net blotch of barley (D. teres) was favoured especially at the lower ozone concentrations and on the older leaves. Results are discussed with respect to the increase of leaf diseases in cereal production since about two decades
Sulfur containing air pollutants and their effects on plant metabolism
No full textH2S and SO2 affected plant yield at relative low levels without causing visible injury. In general H2S was more toxic than SO2. Short-term exposure (24 to 48 h) of plants to the pollutants affected sulfur, nitrogen and energy metabolism. Both exposure of plants to H2S and SO2 resulted in an accumulation of glutathione in the leaves; this accumulation was higher in H2S than in SO2 exposed plants. SO2 exposure resulted in a rapid accumulation of sulfate, which was absent in H2S exposed plants. Amino acid metabolism in spinach leaves was strongly affected by short-term H2S exposure. Besides a strong increase in the cysteine content, there was a substantial decrease in the serine content. The content of most other amino acids and ammonia increased upon exposure, which indicated an overall effect of H2S on amino acid/protein metabolism. In vivo nitrate reductase activity measured under aerobic conditions was increased in H2S exposed spinach leaves. Leaf respiration was not affected by H2S exposure. NADH oxidation by other cytosolic enzymes was inhibited in H2S exposed plants, and the level of inhibition correlated with the reduction in relative growth rate by H2S
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
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
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