1,720,956 research outputs found
Modeling the extrinsic incubation of Dirofilaria immitis in South America based on monthly and continuous climatic data
No full textThe spread and recrudescence of dirofilariosis across several regions, either caused by Dirofilaria immitis or D. repens, responds to many factors. Building upon the temperature model by Slocombe et al. (1989), a number of studies have been performed to generate predictive models for dirofilariosis. These studies have demonstrated the length of transmission periods and the number of Dirofilaria generations supported throughout several regions of the world (either at large or at small-scale). The usual procedure have proved to be extremely time consuming, as it appears impractical when assessing potential transmission at large scale, such as at a country or large-scale level. Due to the increasing need to suggest standardized surveillance protocols and apply adequate preventive measures at national and regional levels, a model for calculation of Dirofilaria HDUs based on monthly data was adapted for large-scale regional use. The models proposed are based on both point data (meteorological stations) and interpolated climate data layers (WorldClim). Three different models (daily and monthly models based on point data, and monthly model based on continuous data) were developed and compared statistically. When compared with the results from the classical daily model, the monthly models proposed accurately predicted the locations were extrinsic incubation was possible. These models proved to be adequate for the regional analysis of the extrinsic incubation of D. immitis and, hence, the relative risk of transmission in South America. Further, these models confirm that favorable temperatures for heartworm transmission in South America are present in most of the countries. D. immitis extrinsic incubation follows a seasonal pattern in Argentina, Chile, Uruguay, eastern Paraguay and southeastern Brazil; while in northern half of South America (less than 25° S) transmission may occur year-round. Moreover, high risk areas suitable for dirofilariasis transmission are not geographically constant throughout the year. The validation procedures indicate that the predicted HDU and HG maps are good predictors of dirofilariosis potential distribution, but estimating dirofilariosis prevalences based on them might not be completely accurate. The resulting distribution and seasonal maps would be useful for heartworm prevention by chemoprophylaxis in different regions known to be endemic for canine dirofilariasis. The information here provided can be an important tool in veterinary public health, as well as a guide for future research
Analysis of climate and extrinsic incubation of Dirofilaria immitis in southern South America.
No full textDirofilariosis, caused by Dirofilaria immitis and D. repens, is spreading in several geographic regions. The deve -
lopment of infective larvae in the mosquito vector (extrinsic incubation) needs an accumulated total of 130 degree-days
above the 14 oC threshold, normally expressed as heartworm development units (HDUs). Based on this information, temperature-
based models have been developed and applied to evaluate the distribution and spread of Dirofilaria infections in
various countries and continents. Despite the confirmed presence of D. immitis in most South American countries, the available
information about its epidemiology remains scarce. We analysed the temporal and spatial extrinsic incubation of this
parasite in Argentina, Chile and Uruguay, taking into account daily temperatures from 49 meteorological stations during a
30-year period (1982-2012). The theoretically possible number of D. immitis generations was calculated based on the number
of meteorological stations that reached the 130-HDUs threshold. The resulting information was spatially interpolated
using the inverse weighted distance (IWD) model to produce thematic maps. The model shows that 41 of the meteorological
stations reach the threshold needed and that D. immitis transmission is markedly seasonal with a peak in late spring
(December), stable during summer (January to March) and declining in the autumn (April and May). Suitable temperatures
exist in Uruguay and most of Argentina, whereas D. immitis transmission in Chile is only possible in the north and in the
central inlands. The results suggest that the climatic impact on D. immitis transmission must have been minimal in the countries
investigated since the annual meteorological records did not change much during the 30-year period analysed
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
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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