1,720,963 research outputs found
Diversity of photoreceptor arrangements in nocturnal, cathemeral and diurnal Malagasy lemurs
No full textThe lemurs of Madagascar (Primates: Lemuriformes) are a monophyletic group that has lived in isolation from other primates for about 50 million years. Lemurs have diversified into species with diverse daily activity patterns and correspondingly different visual adaptations. We assessed the arrangements of retinal cone and rod photoreceptors in six nocturnal, three cathemeral and two diurnal lemur species and quantified different parameters in six of the species. The analysis revealed lower cone densities and higher rod densities in the nocturnal than in the cathemeral and diurnal species. The photoreceptor densities in the diurnal Propithecus verreauxi indicate a less “diurnal” retina than found in other diurnal primates. Immunolabeling for cone opsins showed the presence of both middle-to-longwave sensitive (M/L) and shortwave sensitive (S) cones in most species, indicating at least dichromatic color vision. S cones were absent in Allocebus trichotis and Cheirogaleus medius, indicating cone monochromacy. In the Microcebus species, the S cones had an inverse topography with very low densities in the central retina and highest densities in the peripheral retina. The S cones in the other species and the M/L cones in all species had a conventional topography with peak densities in the central area. With the exception of the cathemeral Eulemur species, the eyes of all studied taxa, including the diurnal Propithecus, possessed a tapetum lucidum, a feature only found among nocturnal and crepuscular mammal
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
Using environmental niche models to identify Malagasy bat biodiversity hotpots and conversation priorities in the face of climate and human land use changes.
Get PDFMaster of Science in Biological and Life science. University of KwaZulu-Natal, Durban, 2016.Madagascar represents a global hotspot of endemism, but it faces numerous threats to its biodiversity, including impacts of climate and human land use changes. In this study, suitable habitat space of 25 Malagasy bat species was modelled under past, current and future climate projections, asking three questions: (i) Do Malagasy bat richness hotspots change over different climatic projections and human land use in the past to present to future?; (ii) Do current and future hotspots fall within Madagascar’s current protected areas (PAs)?; and (iii) Can areas be included in the current protected areas to better protect the Malagasy bat hotspots? A decline in suitable habitat space for bat species was anticipated, and, hence, decreased hotspots under warmer (Last Inter-glacial (LIG) and future) climate scenarios, particularly in combination with human land use. It was also expected that changes in climate would influence bats similarly within functional groups (FGs) and differently across functional groups. Specifically, it was predicted that bats adapted to forage in vegetation (clutter FG) should be more affected than bats adapted to hunt insects near vegetation (clutter-edge FG) and high above vegetation (open-air FG). It was further predicted bat richness hotspots would have poor coverage by Madagascar’s PA network for current and future scenarios, due to broad distribution ranges of bats and limited area coverage of PAs across the island. Suitable habitat space was modelled for bat species using environmental niche models (ENMs), taking an ensemble modelling approach to identify the most suitable ENM for each species. Species richness was quantified by stacking suitable habitat maps of individual bat species. The results showed that richness hotspots shifted in size and geographic position under different climate change scenarios. Generally, changes from warm to cold climates decreased the potential suitable habitat space of clutter bats yet increased those of clutter-edge and open-air bat species. In contrast, changes from cold to warmer climates decreased the suitable habitats of clutter bats more than those of clutter-edge and open-air bats. Null model analyses showed that under both cold and warm climatic conditions, the observed overlap in suitable habitat between clutter and clutter-edge functional groups was lower than expected, whereas overlap in suitable habitat between clutter-edge and open-air functional groups was higher than expected by chance. Further, suitable habitat space of bat species was only partially covered by the PA system for climate change and human land use scenarios (range 2 – 20%). Although most of the bat richness hotspots are in PAs, this coverage will decrease with predicted future climate change. It is suggested that an additional 58,077 km should be added to the current protected areas to ensure adequate protection under future climate and land use
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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