1,721,037 research outputs found
A Multidimensional Framework for Assessing the Direct and Indirect Effects of Urbanization on Avian Breeding Fitness: Integrating Environmental Factors, Food Resources, and Citizen Science for Species Conservation in Urban Landscapes
No full textUrbanization is one of the defining issues of the Anthropocene, leading to dramatic transformation of land-cover patterns all around the Earth. This transformation has detrimental effects on global biodiversity and threatens the carrying capacity of our ecosystems. Three key environmental issues are associated with urbanization. First, urbanization affects ecosystem functioning and, particularly where it becomes more intense, it often results in reduced species richness and abundance. Second, the urban heat-island effect (UHI) and sensory pollutants such as noise pollution and artificial light at night (ALAN) cause detrimental effects on wildlife by advancing breeding dates, impairing communication and reducing breeding fitness. Third, urbanization can also imply a reduction in available food resources that is commonly perceived as the main constraint to breeding fitness for urban organisms — usually referred to as the food limitation hypothesis. The overall aims of this study were therefore to investigate how these different factors directly and indirectly interact, and their relative importance in shaping the fitness of wild organisms. The Barn Swallow Hirundo rustica is a perfect model species to study these questions. This human commensal is one of the few species that has coexisted with humans for thousands of years, and in China it is regarded as a symbol of good luck. It is also an aerial insectivore that benefits farmlands and croplands and controls urban pest populations, and its diet overlaps with many other insectivores, making the results applicable to a wide range of urban species. Moreover, Barn Swallow populations and other aerial insectivores are experiencing steep declines all around the world. Investigating the current status of Barn Swallow rural and urban populations, its interactions with humans, and deepening our understanding on the consequences of increased urbanization, are thus top research priorities. Here, I first developed a multidimensional framework to act as a theoretical foundation for understanding how different facets of the urban ecosystem interact to affect bird breeding fitness. In my first field project, I collected Barn Swallow breeding data regarding laying dates, clutch size, number of hatchling and fledgling, hatching and fledging success, and insect biomass at the colony level, quantifying environmental variables and dietary composition for active nests (N=53) at the nest and colony level. The results showed that urbanization and laying behavior were directly related to insect abundance, phenological mismatch and diet of Barn Swallows while UHI was indirectly related to phenological mismatch and diet. Finally, direct negative effects of insect diets (e.g., flies) on fledging success of Barn Swallows, and indirect positive effects on fledging success of later laying date were recorded. In the second field project, I used Barn Swallow nesting locations from a nationwide citizen science as well as associated environmental variables at the site and landscape levels. This study revealed that UHI effects at the site scale, and ALAN and road simplicity at the landscape scale were positively associated with Barn Swallow nest abundance while building year had a negative impact on Barn Swallow nests. Overall, results suggest Barn Swallow can respond to these mixed effects at multiple spatial scales and efficiently adapt to various environmental conditions across the urbanized landscape. The studies presented in this thesis demonstrated that adopting a multidimensional framework in urban ecology can lead to a comprehensive understanding of both direct and indirect, as well as positive and negative effects of urbanization and environmental factors on species’ habitat selection and breeding parameters. Utilizing a multidimensional framework also enables us to plan and design urban environments in order to minimize the adverse impacts of urbanization for both biodiversity and people
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
Seasonal changes in mixed-species bird flocks and anti-predator information
No full textAnimals acquire information produced by other species to reduce uncertainty and avoid predators. Mixed-species flocks (MSFs) of birds are ubiquitous in forest ecosystems and structured, in part, around interspecific information transfer, with 'nuclear' species providing information that other species eavesdrop on. We hypothesized that in a seasonal tropical forest, the amount of information produced by birds about predation would be dynamic, and particularly would decrease inside MSFs when the nuclear species leave MSFs to breed. We obtained baseline information on MSF encounter rate and species composition along established sampling routes over nine months near the Sino-Vietnamese border. We also conducted three experiments to quantify information produced by different species in response to typical predator encounters, including a moving predator stimulus presented inside of MSFs, and a stationary predator model presented both inside and outside of MSFs. MSFs were much less frequent in the breeding season with fewer individuals of the nuclear species, David's Fulvetta (Alcippe davidi), participating, though the diversity of other species remained stable. Fulvettas were the dominant producer of alarm-related information both to the moving and stationary stimuli in MSFs, and were also among the most active mobbers to stimuli presented outside of MSFs. In the breeding season they tended to call less to the moving stimulus, and substantially fewer individuals responded to the in-flock stationary stimulus. Other species increased their own information production at stationary predator stimuli (inside and outside of MSFs) during the breeding season, perhaps due to their increased investment in offspring during this time. Yet even during the breeding season, David's Fulvetta remained the highest producer of information about predators in MSFs. Hence, while we show that information production in MSFs can be somewhat dynamic, we describe a continually asymmetric communication system, in which a nuclear species is important to the whole community.Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 31560119Funding provided by: Innovation Project of Guangxi Graduate Education*Crossref Funder Registry ID: Award Number: YCBZ2018011Funding provided by: Innovation Project of Guangxi Graduate EducationCrossref Funder Registry ID: Award Number: YCBZ2018011Please see the manuscript. Abbreviations for bird species are in Table 2
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