1,721,121 research outputs found
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
Collective decision-making in homing pigeon navigation
Full text linkThis thesis focuses on conflict resolution and collective decision-making in co-navigating pigeons, Columba livia. These birds have a remarkable homing ability and frequently fly in flocks. Group navigation demands that group members reach consensus on which path to follow, but the mechanisms by which they do so remain largely unexplored. Pigeons are particularly suitable for studying these mechanisms, due to their sociality and the fact that their possession of information can easily be altered and quantified. I present the results of a series of experiments that manipulated the experience of homing pigeons in various ways so as to observe the effect of information they had previously gathered on their group behaviour. Key findings were: Previous navigational experience contributes to the establishment of leader-follower relationships. The larger the difference in experience between two co-navigating pigeons, the higher the likelihood the more experienced bird will emerge as leader. Shared homing experience through repeated joint flights can allow two pigeons to develop into a “behavioural unit”. They form spatial sub-groups when flying with less familiar birds, and perform a similar transition between compromise- and leadership-dominated flights as single birds, although they are more likely to accept compromise routes. Such previous association histories between birds can thus affect collective decision-making in larger flocks. There is a trade-off between the amount of spatial information handled and the efficiency with which such information can be applied during homing. Leading/following behaviour is influenced by the recency of the route memories. Leadership hierarchies in pigeon flocks appear resistant to changes in the navigational knowledge of a subset of their members, at least when these changes are relatively small in magnitude. The stability of the hierarchical structure might be beneficial during decision-making. Mathematical modelling suggests that underlying hierarchical social structures can increase navigational accuracy. Hierarchically organised groups with the smallest number of strong connections achieve highest accuracy. Group leader-follower dynamics resemble the underlying social structure
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
Consequences and mechanisms of leadership in pigeon flocks
Full text linkThis thesis investigates how collective decisions in bird flocks arise from simple rules, the factors that give some birds more influence over a flock's direction, and how travelling as a flock affects spatial learning. I used GPS loggers to track pigeons homing alone and in flocks, and applied mathematical modelling to explore the mechanisms underlying group decisions. Across several experiments, the key results were as follows: Flying home with a more experienced individual not only gave a pigeon an immediate advantage in terms of taking a more direct route, but the followers also learned homing routes just as accurately as pigeons flying alone. This shows that using social cues did not interfere with learning about the landscape during a series of paired flights. Pigeons that were faster during solo homing flights also tended to fly at the front of flocks, where they had more influence over the direction taken. Analysis of momentary interactions during paired flights and simulations of pair trajectories support the conclusion that speed increases the likelihood of leading. A pigeon's solo homing efficiency before flock flights did not correlate with leadership in flocks of ten, but leaders did have more efficient solo tracks when tested after a series of flock flights. A possible explanation is that leaders attended more to the landscape and therefore learned faster. Flocks took straighter routes than pigeons flying alone, as would be expected if they effectively pooled information. In addition, pigeons responded more strongly to the direction of several neighbours, during flock flights, than to a single neighbour during paired flights. This behaviour makes sense adaptively because social information will be more reliable when following several conspecifics compared to one. Through a combination of high-resolution tracking and mathematical modelling, this thesis sheds light on the mechanisms of flocking and its navigational consequences
Chimpanzee culture in Cantanhez National Park, Guinea-Bissau
Full text linkThe existence of non-human animal (hereafter animal) culture, i.e., behaviours that are group-typical and shared by members of a community through social learning, is now generally accepted. Its presence has been identified in many vertebrate, and even invertebrate, species. Much like in humans, culture is present in the most diverse aspects of an animal’s life, from complex material culture, communication, and social behaviours, to foraging, travel, and migratory routes. Importantly, culture can be a source of adaptive behaviour whereby individuals can more readily discover the solution to a problem if they attend to or copy the behaviour of other individuals facing the same problem, allowing individuals to better exploit their natural and social environment. Of all animal species, chimpanzees (Pan troglodytes) have the largest known cultural repertoire. However, despite several long-term field studies, large gaps remain in our knowledge of the behavioural repertoire of and behavioural variation across the majority of Africa’s chimpanzees. Furthermore, few studies have compared the behaviour of neighbouring chimpanzee communities, despite such comparisons promising to provide the strongest evidence for culture, and few have studied communities inhabiting anthropogenic landscapes, although their culture is in the most imminent danger of disappearing.
The aim of this thesis was to study behavioural variation across four unhabituated neighbouring chimpanzee (Pan troglodytes verus) communities, inhabiting an agroforest habitat matrix in Cantanhez National Park (CNP), Guinea-Bissau. As these critically endangered chimpanzees regularly encounter local people and a loss of fear of humans might drive aggressive interactions, habituation was never a possibility. Therefore, a combination of direct opportunist observations, but mostly indirect methods of data collection (e.g., camera traps, abandoned tools, nests) were employed. Additionally, a combination of data analysis methodologies – automated behavioural annotation, primate archaeology techniques, and stable isotope analysis – were used to tackle the large data set collected, which included 4197 chimpanzee videos, 1747 indirect chimpanzee traces, 125 chimpanzee hair samples, and 390 plant samples.
In Chapter 2 I compile a list of 18 putative cultural behaviours for CNP’s chimpanzees, some of which had never been described for Guinea-Bissau, or even the rest of tropical Africa, and describe evidence of inter-community variation that spans tool use, communication, and social behaviour. In Chapter 3 I focus on a subset of these cultural behaviours – honey dipping – and describe inter-community variation as well as variation in tools used to collect the honey from different insect species. Employing primate archaeological techniques, I assign putative functions to the collected tools and suggest that different tools are used as part of a tool set. In Chapter 4, with the aid of an automated, machine learning based drumming annotation software, I examine a chimpanzee ‘universal’ – buttress drumming – and identify inter-community variation in drumming duration. Through exploring the contexts in which drumming occurs, I further suggest that the duration of a drumming bout might be part of community-specific signalling in particular contexts, such as travel. Finally, in Chapter 5 I use stable isotope analysis and find significant inter-community variation in the diets of these neighbouring chimpanzees, that point towards previously unknown differences in feeding behaviour.
Overall, this thesis presents the first long-term study focussed on chimpanzee behavioural variation in CNP, highlighting the importance and feasibility of simultaneously studying multiple neighbouring communities, without the need for habituation. Technological advances have not only changed the way we collect data but also the type and amount of data we can collect and analyse, allowing us to closely examine many aspects of an animal’s life. Finally, this study underlines how different communities facing similar environmental pressures can adopt different adaptations, even at a local scale. Given the rate of habitat destruction and climate change that wild species are facing, there has never been a more relevant time to study how different communities behave and adapt to life in the Anthropocene
- …
