1,720,959 research outputs found
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
Ecological systems in space: From islands to contiguous landscapes
Get PDFDispersal and interaction networks underlie many ecological systems, often dictating spatio-temporal dynamics as well as emergent patterns. Dispersal has implications for establishment for distinct subpopulations of individual species as well as for the emergence of universal spatial patterns and varied community level structures. Such implications and the search for mechanisms that drive them are the central themes of this thesis. The accompanying manuscripts discuss two very different approaches of analysing ecological systems. The less complex of the two systems consists of sites along a coastal landscape that harbours the seagrass Halodule uninervis. The task is to partition the entire population into subpopulations that have very little dispersal across them. We use an algorithm to aggregates sites that are more strongly connected in the same subpopulation for a range of dispersal scenarios. These scenarios are useful since the dispersal processes and life-spans of the seagrass are not well-understood. In subsequent work, the idea of complexity is more precise. We analyse ecosystems whose complexity is captured by the strength of interactions between species and the fraction of interaction links realized out of all possible ones. On one hand we study how ecological communities on islands are assembled from a large pool of species that can also immigrate from the mainland source, and if it can provide mechanisms to explain the scaling of species richness with island areas – namely the species-area relationship. A drastically different setting is large contiguous landscapes. We posit that species interactions vary across space, which helps characterize habitat patches that would be connected by high dispersal of species. This simplified picture provides a range of situations to understand how habitat heterogeneity affects species richness.An overarching theme in investigating these complex ecological systems is to first analyze the fully random case without assuming any structure. This null case admits description in terms of a few statistics that greatly simplify the study of system level properties and processes. One can then ask if there are parameter regimes where these properties break down. The difficulty in finding such regimes might indicate universal properties but even the sudden disappearance might unravel phase transitions or unexplored new properties
Ecological systems in space: From islands to contiguous landscapes [Elektronisk resurs]
No full textDispersal and interaction networks underlie many ecological systems, often dictating spatio-temporal dynamics as well as emergent patterns. Dispersal has implications for establishment for distinct subpopulations of individual species as well as for the emergence of universal spatial patterns and varied community level structures. Such implications and the search for mechanisms that drive them are the central themes of this thesis. The accompanying manuscripts discuss two very different approaches of analysing ecological systems. The less complex of the two systems consists of sites along a coastal landscape that harbours the seagrass Halodule uninervis . The task is to partition the entire population into subpopulations that have very little dispersal across them. We use an algorithm to aggregates sites that are more strongly connected in the same subpopulation for a range of dispersal scenarios. These scenarios are useful since the dispersal processes and life-spans of the seagrass are not well-understood. In subsequent work, the idea of complexity is more precise. We analyse ecosystems whose complexity is captured by the strength of interactions between species and the fraction of interaction links realized out of all possible ones. On one hand we study how ecological communities on islands are assembled from a large pool of species that can also immigrate from the mainland source, and if it can provide mechanisms to explain the scaling of species richness with island areas – namely the species-area relationship. A drastically different setting is large contiguous landscapes. We posit that species interactions vary across space, which helps characterize habitat patches that would be connected by high dispersal of species. This simplified picture provides a range of situations to understand how habitat heterogeneity affects species richness. An overarching theme in investigating these complex ecological systems is to first analyze the fully random case without assuming any structure. This null case admits description in terms of a few statistics that greatly simplify the study of system level properties and processes. One can then ask if there are parameter regimes where these properties break down. The difficulty in finding such regimes might indicate universal properties but even the sudden disappearance might unravel phase transitions or unexplored new properties
Structure, stability and macroecology of populations and ecosystems [Elektronisk resurs]
No full textDispersal and interaction networks underlie many ecological systems, often dictating spatio-temporal dynamics as well as emergent patterns. The mode and time scales of dispersal can vary considerably depending on whether ecosystems exist in contiguous landscapes or in island-like configurations. In particular, island systems have been extensively studied for many ecological processes, in part because of the simplicity in representing processes such as immigration of organisms from outside. This representation has also been used in many other habitats, such as mountain tops which can also be considered island-like because of their isolation and similar properties of immigration. Immigration could result from species that already exist on the islands or those that are novel. This distinction connects to the concept of species invasions which are driven by new species not present in an ecosystem before. Invasions can be seen as an important part of how ecosystems are assembled. Invasive species can also have disruptive impacts on systems like islands, which for example can introduce novel species like predators. Invasions serve as a useful representation of various means and ends of biological processes, and hence their study has extended way beyond their initial scope. Dispersal, interactions and invasions have implications ranging from establishment of distinct subpopulations of individual species to large scale spatial patterns that define ecosystems. Such implications and frameworks to explain them are the central themes of this thesis. One of the systems we study consists of sites along a coastal landscape that harbours the seagrass Halodule uninervis. The task is to partition the entire population into subpopulations that have very little dispersal across them. We use an algorithm to aggregates sites that are more strongly connected in the same subpopulation for a range of dispersal scenarios. These scenarios are useful since the dispersal processes and life-spans of the seagrass are not well-understood. The other articles focus on ecological communities with a range of interaction types between species. We study how ecological communities on islands are assembled from a large pool of species that can also immigrate from the mainland source, and if it can provide mechanisms to explain the scaling of species richness with island areas -- namely the species-area relationship. A drastically different setting is large contiguous landscapes. We posit that species interactions vary across space, which helps characterize habitat patches that would be connected by high dispersal of species. This simplified picture provides a range of situations to understand how habitat heterogeneity affects species richness. We also address the problem of how ecosystems with many interacting species can still be stable. We do this by deriving a very general mathematical bound on stability which is expressed in terms of ecologically realistic constraints. Species identities are important with respect to biological invasions for the risk of replacement of resident species. We developed a framework to predict the structure of invasion outcomes, i.e., what set of species survive following an invasion event. This method is applicable in a range of cases characterized by high initial abundance of invaders and imperfect knowledge of interactions. An overarching theme in investigating these complex ecological systems is to first analyze the fully random case without assuming any structure. This null case admits description in terms of a few statistics that greatly simplify the study of system level properties and processes. One can then ask if there are parameter regimes where these properties break down. The difficulty in finding such regimes might indicate universal properties but even the sudden disappearance might unravel phase transitions or unexplored new properties
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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