1,721,046 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
Taxonomy and life history of the zebra seabream, Diplodus cervinus (Perciformes: Sparidae), in southern Angola
Get PDFThe zebra sea bream, Diplodus cervinus (Sparidae) is an inshore fish comprised of two boreal
subspecies from the Gulf of Oman and the Mediterranean / north eastern Atlantic and one
austral subspecies from South Africa and southern Angola. The assumption of a single austral
subspecies has, however, been questioned due to mounting molecular and morphological
evidence suggesting that the cool Benguela current is a vicariant barrier that has separated
many synonymous inshore fish species between South Africa and southern Angola. The aims
of this thesis are to conduct a comparative morphological analysis of Diplodus cervinus in
southern Angola and South Africa in order to classify the southern Angolan population and
then to conduct a life history assessment to assess the life history impact of allopatry on this
species between the two regions.
Results of the morphological findings of the present study (ANOSIM, p < 0.05, Rmeristic = 0.42)
and (Rmorphometric = 0.30) along with a concurrent molecular study (FST = 0.4 – 0.6), identified
significant divergence between specimens from South Africa (n = 25) and southern Angola (n
= 37) and supported stock separation and possibly sub-speciation, depending on the
classification criteria utilised. While samples from the two boreal subspecies were not available
for the comparative morphological or molecular analysis, comparisons of the colouration
patterns between the three subspecies, suggested similarity between the southern Angola and
the northern Atlantic / Mediterranean populations. In contrast, the colouration patterns between
the southern Angolan and South African specimens differed substantially, further supporting
the morphological and molecular results.
The distinct morphological divergence between the southern Angolan and South African
populations was not reflected within the life history traits of both populations. A combination
of methods, including length/age frequency analyses, adult sex ratios and histological analysis
was used to determine that this species is a rudimentary hermaphrodite in southern Angola.
Peak spawning season was observed between June and July. The overall sex ratio (M: F) was
1:1.52 with females dominating smaller younger size classes and 50% maturity was attained at
210 mm FL and 4.6 years. Females [L(t) = 287.5(1-e⁻°·¹⁸⁽t⁻²·⁸⁴⁾)] grew significantly faster (LRT,
p < 0.05) than males [L(t) = 380.19(1-e⁻°·°⁶⁽t⁻⁷·¹²⁾)]. The higher maximum age of the southern
Angolan population of D. cervinus (43 years) was older than that of South African individuals
sampled in the tsitsikamma national park. The similarities in the life history of the two austral populations are probably a consequence of similar selective pressures in the similar warmtemperate
habitats.
Evidence to support the above comments was found in the feeding study which showed that
the South African and Angolan populations were almost identical, with both populations
feeding primarily on amphipods and polychaete worms throughout ontogeny. In contrast, the
diet of their boreal conspecifics from the Mediterranean was different, where larger individuals
tended to select larger, and more robust, prey items.
The life history differences observed between the boreal and austral populations can be
attributed to either sampling bias or environmental factors. Sampling biases included the use
of different age and growth estimation techniques, while the environmental factors would
include differential selective pressures most likely driven by different resource availability and
exploitation.
The present study provides crucial baseline life history information of a potentially exploitable
species off southern Angola as well as information on the life history plasticity of the species.
Unfortunately, the current lack of uniformity in the methods used to estimate life history
parameters between studies conducted on the boreal and austral populations have complicated
our understanding of the evolution of various life history trends in sparid fish. From a
management perspective however, the results from the present study can be used to propose
management strategies for an emerging trap fishery in southern Angola. Using a balanced
exploitation fishery approach (harvesting up to the size-at-100% maturity), the size of the fish
traps entrance was calculated based the morphological information from this and other small
sparid species that are targeted and was estimated to be 62 mm
Business Papers (MS 80-0003)
No full textLetter from Ernest A. Mantzel to Warren Potts asking who gave him permission to use one of his buildings
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
The taxonomy, life-history and population dynamics of blacktail, Diplodus Capensis (Perciformes: Sparidae), in southern Angola
Get PDFThe blacktail, Diplodus capensis, is an inshore sparid fish distributed from Mozambique to
Angola. This species forms an important component of coastal fisheries within its
distribution, one being the subsistence handline fishery in southern Angola. With this fishery
being critically important to the livelihoods of local communities, a biological study and
stock assessment was conducted to provide information for the management of this species in
southern Angola. However, with molecular evidence suggesting that the Benguela current
may have separated the southern African populations of many inshore fish species over two
million years ago, a morphological, taxonomic analysis was considered necessary to first
investigate whether there was evidence for allopatry in this species.
A total of 46 morphometric measurements and 18 counts were carried out on specimens
collected from various locations in southern Angola and South Africa. Results were analysed
using multi-dimensional scaling (MDS) and the significance of clusters was tested using
analysis of similarities (ANOSIM). Biological samples of D. capensis were collected
monthly from an unexploited area from April 2008 to March 2009. Additional biological
samples were collected from the subsistence fishers in an exploited area during May, June
and December 2009. Standard biological laboratory techniques were employed for the lifehistory
comparison between the exploited and unexploited area. A per-recruit analysis was
conducted using the life-history parameters from both areas in order to assess the current
status of the subsistence fishery and to investigate the potential short-falls of the per-recruit
assessment approach.
The morphometric comparison showed that there was not sufficient evidence for speciation
between the southern Angolan and South African populations of D. capensis. There was,
however, sufficient morphological evidence to suggest that these populations are separate
stocks. This indicated that the existing reference points on which the management of the
South African population is based are unsuitable for the Angolan population. Diplodus
capensis in southern Angola is omnivorous, feeding predominantly on algae, barnacles and
mussels. An ontogenetic shift from algae to barnacles and mussels was correlated with
allometric growth patterns in their feeding apparatus. This species is a rudimentary
hermaphrodite in southern Angola with peak spawning in June and July. The overall sex ratio (M: F) was 1: 4.7 in the unexploited area and 50% maturity was attained at 149.5mm FL and
five years. Diplodus capensis in southern Angola exhibits very slow growth with the
maximum age observed being 31 years (validated using mark recapture of chemically
injected fish). Females [L(t) = 419.5(1-e⁻°·°⁴⁵⁽t⁻³·⁴ ⁾)] grew significantly faster (LRT, p < 0.05)
than males [L(t) = 297.4(1-e⁻°·°⁷⁷⁽t⁻²·⁷⁾)], and females dominated the larger size classes and
older age classes. In the exploited area, the length and age frequencies were severely
truncated, the maximum observed age was greatly reduced (17 years) and the sex ratio was
less female biased at 1: 2.2. Although there was no evidence for a physiological response to
exploitation through alterations in growth or size/age at sexual maturity between the two
areas, there was an increase in the proportion of small females in the exploited area, which
may have been a compensatory response for the loss of large females. A combination of an
underestimate of longevity, different estimates of the Von Bertalanffy growth parameters and
overestimates of the natural mortality rate in the exploited population resulted in a 92%
underestimate of the pristine spawner biomass-per-recruit (SBR) value. An assessment based
on the actual pristine SBR estimate from the unexploited area revealed that the subsistence
fishery had actually reduced D. capensis to 20% of its pristine SBR levels and highlighted the
value of pre-exploitation life-history information for the application of per-recruit models.
This study has shown that D. capensis in southern Angola displays life-history characteristics
that render it susceptible to overexploitation, even at low levels of fishing pressure. The
current lack of infrastructure and enforcement capacity in the fisheries department of Angola
renders traditional linefish regulatory tools, such as size limits, bag limits and closed seasons,
inappropriate. Therefore, suitably designed marine protected areas are recommended as the
best management option for this species
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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