1,720,955 research outputs found
Micro-epidemiología molecular de las infecciones que contribuyen a mantener la transmisión de Plasmodium vivax en comunidades en vías de eliminación de la malaria en la Región Loreto
Get PDFLa transmisión de la malaria sigue siendo un problema de salud pública persistente en la Amazonía peruana, reflejada en la alta morbilidad de casos causados por Plasmodium vivax dentro de un contexto de malaria residual a nivel micro-epidemiológico. Ante esta situación, resulta imperativo emplear herramientas como la genética y la genómica poblacional para comprender mejor los factores que mantienen la transmisión residual de la malaria. El objetivo principal de este estudio fue caracterizar molecularmente la micro-epidemiología de las infecciones por P. vivax que contribuyen a perpetuar la transmisión en comunidades remotas que están en proceso de eliminación de la malaria. En el primer capítulo de esta tesis, los resultados destacan la presencia de un 40% de infecciones submicroscópicas y una alta diversidad genética (He = 0.70 ± 0.10), sin cambios significativos entre los períodos 2013 y 2015-2016 (p-valor > 0.05), así como en otras métricas de diversidad genética. Además, se detectaron parásitos clonales, linajes de diferentes orígenes y flujo genético (Fst > 0.5), evidenciado por la introducción de parásitos genéticamente distintos. Este hallazgo motivó el desarrollo del segundo capítulo, que evaluó a los viajeros infectados y caracterizó los patrones de movilización humana, además de analizar la diversidad genómica poblacional y las relaciones genéticas de los parásitos recolectados en las comunidades de Libertad y Urcomiraño. Se encontró un 21% de infecciones por Plasmodium en los viajeros, de las cuales el 89% eran submicroscópicas. La movilidad humana resultó ser heterogénea, con desplazamientos frecuentes hacia Mazán, Iquitos y varias quebradas. Por último, los parásitos recolectados presentaron baja diversidad genómica, con poblaciones clonales (IBD = 90%), la presencia de flujo genético (Fst = 0.15-0.25) entre Libertad y Urcomiraño, y linajes clonales que se mantuvieron a lo largo del tiempo, en función de la proximidad geográfica y el momento de la recolección. En conclusión, tanto las infecciones submicroscópicas como la movilización humana parecen desempeñar un papel clave en el mantenimiento de la transmisión de la malaria residual, revelando nuevos aspectos, a nivel de la genética de los parásitos, que contribuyen con la micro-epidemiología de la malaria en las comunidades estudiadas.Malaria transmission is a persistent public health problem in the Peruvian Amazon. This persistence is reflected in the increased morbidity of cases caused by P. vivax in a micro-epidemiological context of residual malaria within the Peruvian Amazon. For this reason, there is an urgent need to use tools such as population genetics and genomics to help explain the maintenance of residual malaria transmission at the micro- epidemiological level. The overall objective of this study was to molecularly characterize the micro-epidemiology of P. vivax infections that contribute to the maintenance of transmission in remote communities undergoing malaria elimination. The results in Chapter 1 of this thesis highlight the presence of 40% submicroscopic infections, with high genetic diversity (He=0.70 ± 0.10) with no significant changes (p-value>0.05) between 2013 and 2015-2016 and the other metrics of genetic diversity. Clonal parasites and lineages with different origins were also found, plus the presence of gene flow (Fst>0.5) evidenced by the entry of new genetically unrelated parasites. Due to this last finding, Chapter 2 of this thesis was developed, where the infected travelers were evaluated and the mobilization and human mobilization were characterized, and the population genomic diversity and genetic relationships of the parasites collected in Libertad and Urcomiraño were also evaluated. We found 21.0% of Plasmodium spp. infections in travelers, 89% of these infections were submicroscopic. Human mobilization was heterogeneous with frequent trips to Mazan, Iquitos and creeks. Finally, the parasites collected showed low genomic diversity, with clonal populations (IBD=90%), presence of gene flow (Fst=0.15-0.25) between Libertad and Urcomiraño, plus clonal lineages that have been maintained according to the time of collection and the geographic proximity to the collection site. In conclusion, submicroscopic infections as well as human mobilization are having a role in maintaining residual malaria transmission, at level of parasite genetics, that contributes with the malaria micro-epidemiology in the communities included in this study
Estrategias de control basado en la detección de infecciones por PCR en tiempo real y su efecto en la diversidad genética y la reproducción de Plasmodium vivax en las cuencas Mazan y Napo
Get PDFEste trabajo tuvo como objetivo general evaluar el efecto de estrategias de control en las métricas de diversidad genética y la reproducción de Plasmodium vivax en las cuencas del Mazán y Napo. Se genotipificaron 92 muestras con al menos 75% con perfil completo (mayor a 10 locis) con 16 marcadores microsatélites. Al inicio de la implementación de las tres estrategias (Mes 0) se encontró, una moderada a alta diferenciación poblacional, con bajo flujo genético (Fst> 1.3). Durante la implementación de las tres estrategias, solo la estrategia 1 produjo una disminución significativa (p-valor 0.05) en las métricas genético poblaciones a través del tiempo. Análisis complementarios, mostraron que en Libertad (donde se implementó la estrategia 3) se encontraron infecciones recurrentes y una reducción de casi dos veces más de haplotipos relacionados con respecto al año 2015. No se encontró un efecto reciente cuello de botella en la población parasitaria por cada estrategia. En conclusión, las tres estrategias de control no mostraron cambios en las métricas genético poblaciones, evidenciando la vulnerabilidad al ingreso de haplotipos genéticamente no relacionados
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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