1,720,967 research outputs found
Water use efficiency : what are the implications for plantation forestry? : evidence for sustainable plantation forestry
No full textWater use efficiency (WUE) is the ratio of some measure of growth or carbon assimilation to water utilization. It can be considered at the level of the leaf, whole plant or stand, and can be expressed in terms of total plant biomass or that of harvestable stems. It is a ratio and will be influenced by changes in either or both of the components. WUE is extremely variable with climatic and local weather conditions, soil type and plant age. Increases in yield of harvestable stem would increase WUE, but breeding practices have probably already maximised stem yield. Reductions in transpiration are considered unlikely to be achievable in plants growing in well-watered soils, and any such reductions would probably also bring about reductions in productivity. 'Water conservation' strategies are also unlikely in plants in water-limited soils, as competing neighbours would utilise the conserved water. It is not known whether there are differences among genotypes in intrinsic WUE, but if there are, these are more likely to become apparent under conditions of low, rather than high water availability. However, high WUE may not be a good selection criterion for plants suitable for water-limited conditions; the ability to acquire water and the ability to survive periods without water may be more important than the efficiency with which water is utilised.
Southern African Forestry Journal No.195 2002: 73-7
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
Developmental rates and morphological properties of fibres in two eucalypt clones at sites differing in water availability
No full textOne of the ways in which the global forestry industry can remain competitive is to improve the predictability of properties of fibres produced, particularly in plantations. Since the properties of the fibres are determined by growth and developmental processes, it is of importance to understand these processes and how they are affected by changing environmental conditions. Using two Eucalyptus spp. clones growing at sites contrasting in available water, this study measured the rates of fibre production, fibre transverse radial enlargement and fibre secondary thickening and the duration of the cell cycle, as well as the duration for which the processes of fibre enlargement and wall thickening continued. Samples were taken from the cambial zone in late summer (February–March) and in winter(May–June). The study found that season had the greatest effects on characteristics of the developmental zones as well as on developmental rates and durations, although there were significant effects of both site and clone. This was complicated by significant interactions that occur between genotype, sitetype and short-term variations in environmental conditions. It was found, however, that dry sites, where trees are experiencing comparatively high levels of environmental stress, can be expected to experience greater extremes in developmental processes between seasons, or over relatively short periods, generally, than wetter sites. These sorts of fluctuations will also translate into greater wood quality variation, and hence different site-types should be managed accordingly. Results from this work will contribute to the development of models of xylogenesis which are currently in development.Southern Hemisphere Forestry Journal 2007, 69(2): 71–7
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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