1,720,976 research outputs found
Understanding communities in complex agroforestry systems: methodological advances and ecological implications
Full text linkAgroforestry, the practice of growing crops beneath a canopy of shade trees, is common in tropical regions, and has the potential to provide habitat for wildlife whilst maintaining agricultural production. However, the increasing demand for commodity crops is driving intensification of agriculture in the tropics, which results in the conversion of agroforestry systems into monocultures. This conversion to monocultures drives declines in biodiversity in these habitats, which may in turn cause a drop-off in yields due to loss of ecosystem services. However, the effects of agricultural management on animal communities and the downstream effects on productivity are poorly understood, especially in the Afrotropics.
This project aimed to study the influence of farm management on wildlife communities, and the potential implications for productivity, in African cocoa agroforestry. My research was based on data of bird and arthropod communities in 28 cocoa farms in southern Cameroon. The study farms varied in their shade cover (a proxy for management intensity), from 20% to 100% cover. In these farms we surveyed arthropods using visual surveys, sweep-netting and malaise traps, and birds using mist-netting and acoustic recorders. I investigated trends in bird and arthropod community composition using several statistical methods, including data integration, hierarchical modelling and community modelling.
My results show that the shade cover of farms had a strong influence on animal community composition. Shady (low-intensity) cocoa farms supported higher densities of vulnerable rainforest bird species such as ant-followers and forest specialists. Shady farms also contained higher densities of potential pollinators and natural enemies, and lower densities of pest insects. I investigated the interplay between shade management and interspecific interactions, and found that both these factors were important in shaping communities in these complex agricultural habitats.
Overall, my results indicate that low-intensity management of agroforestry may be beneficial for both biodiversity conservation and productivity, as it favours populations of vulnerable species and ecosystem services providers, whilst reducing pest burdens. These findings shed light on the risks associated to the current push towards intensification of agriculture in the tropics
Birds and bats enhance yields in Afrotropical cacao agroforests only under high tree-level shade cover
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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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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