1,721,015 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
The Impacts of Small and Medium Wind Turbines on Bats
No full textThis thesis examines the impacts of small and medium scale wind turbines upon bats.Global efforts to address climate change have recently introduced a new source of fatality risk to bats, from wind turbines. Bat fatalities have now been confirmed in varying magnitudes at wind energy facilities around the world. Research at large turbines and wind farms has started to produce a knowledge base regarding impacts upon bats, though many questions remain. Little, however, is known about risk levels at small and medium scale wind turbines. Equally, research regarding the impacts of turbines in the UK is limited.
This thesis examines the impacts of small and medium scale wind turbines upon bats. Planning records of wind turbines in Wales and south west (SW) England were reviewed. Approved planning applications for single and double turbine sites were found to greatly outnumber those for larger scale wind farms. The large majority of single and double turbine approvals were also for small turbines. The potential impacts of turbine presence and density on current bat roost populations and population changes were analysed, finding no impact. An estimate of bat fatality rates at small and medium turbines was calculated, using a trained search dog to locate carcasses. An average fatality rate between 0.81 and 15.15 turbine-1 year-1 was estimated. The higher rate accounted for uncertainty in the monitoring protocol. Only 3 bat carcasses were however observed across all monitored turbines, suggesting more stringent monitoring would likely confirm a lower maximum annual fatality rate. Bat activity levels were also compared between the turbine location and differing habitat types. A disturbance effect was consequently identified in proximity to turbines during high wind speeds. Finally moderating influences of environmental weather and habitat conditions upon bat activity were confirmed.
Social Network Analysis (SNA) methods were used to analyse bat movement networks within a small grid of bat detectors centred on each turbine. Associations were identified between bats’ movement routes and habitat structures present at sites, highlighting vulnerabilities to disruption. Furthermore bats actively used the turbine area, potentially for foraging purposes. Finally by assessing bats’ activity levels in response to a turbine noise playback experiment, small turbine noise was found to have no impact upon bat activity. Planning guidance regarding bats and small and medium turbines is highlighted as a priority for policy development.Natural Resources WalesNatural Environment Research Council (NERC
The effect of artificial lighting on bats in Britain
Get PDFArtificial light pollution is increasing on a global scale at an annual rate of 6 per cent. Recent advances in artificial lighting technology are being developed at a faster rate than the ongoing replacement of conventional street lighting. This new technology is consumer driven for a broad band light spectrum, suitable for human vision, but little research has been conducted on its ecological impacts. Although it is known that light pollution can have major adverse affects on a wide array of species and ecological systems, research into the extent of these impacts is in its infancy. The most likely species to be adversely affected are those adapted to dark environments. Due to this, the focus of this thesis is on bats, a common nocturnal taxa in the UK, and the affects of artificial lighting on contrasting species within the taxa.
In this thesis, two approaches were taken; a large scale observational landscape investigation of the impacts of artificial lights (street lights) under current environmental conditions; and a small scale experimental investigation of the responses of bats to three lighting treatments: dark, UV-LED lighting, and filtered UV-LED lighting. In the former investigation, the focus is on a generalist species; Pipistrellus pipistrellus and a specialist genera; Rhinolophus. In both investigations the activity of P. pipistrellus, the most common bat in the UK, did not differ significantly at dark compared to artificially light locations. However, in the landscape study, the rate of foraging was 35% higher in dark locations (0.03 passes per detector night ± SE 1.17) compared to at street lit locations (0.02 ± SE 1.29; P = 0.027). In contrast, the activity of Rhinolophus spp. was 79% higher at dark locations (0.21 ± SE 1.00) compared to at street lit locations (0.04 ± SE 1.00, P = 0.052). No significant effects were found in the experimental study, possibly due to the high variability of bat activity, insufficient replicates and insufficient differences between the light types.
The landscape study confirms that increased artificial lighting will have adverse effects on Rhinolophus spp., limiting the available habitat in the landscape for commuting and foraging. In contrast, P. pipistrellus activity was not affected by artificial lighting. However, reduced foraging was found in these locations, possibly due to altered insect composition at artificially lit locations, which may have negative indirect affects for this species. These results highlight the wider importance for all species of the ecological impacts of artificial lighting and contribute to the growing body of research in this area which discourages the continued trend for illuminating naturally dark environments
The Social Structure, Ecology and Pathogens of Bats in the UK
No full textThis thesis examines the ecology, parasites and pathogens of three insectivorous bat species in Wytham Woods, Oxfordshire; Myotis nattereri (Natterer’s bat), M. daubentonii (Daubenton’s bat) and Plecotus auritus (Brown long-eared bat).
The population structure was assessed by monitoring associations between ringed individuals, utilising recent advances in social network analysis. Populations of both M. daubentonii and M. nattereri were found to subdivide into tight-knit social groups roosting within small areas of a continuous woodland (average minimum roost home range of 0.23km2 and 0.17km2 respectively). If this population structure is a general attribute of these species it may make them more sensitive to small scale habitat change than previously thought and has implications for how diseases may spread through the population.
M. daubentonii had a strong preference for roosts close to water, away from woodland edge and in areas with an easterly aspect. The factors driving roost choice in M. nattereri and P. auritus remain elusive. The segregation of M. daubentonii into bachelor and nursery colonies was not a result of the exclusion of males from roosts close to water by females, or variation in microclimate preferences between the sexes, as was predicted. Body condition (weight/forearm length) was correlated with host characteristics including age and reproductive status, and weather variables.
Astroviruses and Coronaviruses, which have characteristics typical of zoonotic viruses, were identified in UK bat species for the first time. Coronaviruses identified formed species-specific clades while Astroviruses were highly diverse. Though not closely related to human viruses these are potential zoonotic diseases of the future. Models of Coronavirus and ectoparasite distribution suggest individual attributes (e.g. sex and age) and population structure (e.g. the formation of nursery and bachelor colonies) are important predictors of parasite and pathogen prevalence.
This study characterises a system that offers many opportunities for future research including studies of sociality, disease modelling and conservation management
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
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