1,720,972 research outputs found
Investigación diagnóstica de abortos en ovinos de Uruguay
Full text linkA pesar de la importancia económica y sociocultural que posee la ovinocultura en Uruguay, las existencias ovinas han decrecido marcadamente en las últimas décadas. La eficiencia productiva y económica de los sistemas de producción ovina están determinadas en gran medida por la eficiencia reproductiva, que suele ser baja en las majadas uruguayas, dificultando el mantenimiento o incremento de las existencias ovinas. La eficiencia reproductiva se ve afectada negativamente por los abortos y la mortalidad perinatal, los cuales pueden tener diferentes etiologías, poco documentadas en Sudamérica. Gran parte de los problemas sanitarios que determinan abortos en pequeños rumiantes (ovinos, caprinos) son causados por patógenos zoonóticos, y algunos de ellos que han emergido en ciertas partes del mundo, son bacterias multirresistentes a antibióticos. Los objetivos de este trabajo fueron: 1) revisar la información existente sobre abortos de etiología infecciosa y parasitaria en ovinos (y caprinos) de Sudamérica; 2) determinar la frecuencia relativa de causas infecciosas (bacterianas, virales) y parasitarias (protozoos apicomplejos) de abortos mediante diagnóstico laboratorial para la detección directa de patógenos abortivos en ovinos de Uruguay; 3) determinar la susceptibilidad antimicrobiana de las bacterias aisladas de casos con diagnóstico etiológico de aborto bacteriano; y 4) estimar la seroprevalencia a cuatro patógenos con potencial de causar aborto en majadas con historia reciente de aborto. Para el primer objetivo se revisó la bibliografía publicada sobre abortos bacterianos, protozoarios y virales en ovinos (y caprinos) de Sudamérica y se evaluó si los reportes fueron concluyentes en demostrar la causalidad de los abortos usando un criterio preestablecido de clasificación (causa posible, probable o confirmada). En la actualidad, las causas confirmadas de abortos en ovinos en la región son Campylobacter fetus subesp. fetus, Campylobacter jejuni, Leptospira spp., Listeria ivanovii, Toxoplasma gondii, Neospora caninum y Sarcocystis spp. Por otro lado, Brucella ovis, Brucella melitensis, Bacillus licheniformis y el virus de la lengua azul, son probables causas de aborto en ovinos de la región ya que se han detectado en fetos abortados y/o se han asociado a abortos mediante estudios seroepidemiológicos. Existen otros agentes que están presentes en la región, que aunque no han sido asociados con abortos (Listeria monocytogenes, Yersinia spp., pestivirus, entre otros), deberían considerarse posibles casusas de aborto. Con respecto al segundo objetivo, se analizaron 100 casos de aborto (fetos y/o placentas) mediante técnicas patológicas, moleculares, bacteriológicas y serológicas. Se logró un diagnóstico causal en 46 casos, de los cuales 33 correspondieron a agentes infecciosos y 13 a distocia. Las causas infecciosas incluyeron a T. gondii (n=27), Campylobacter fetus subesp. fetus (n=5) y Campylobacter sp. (especie no identificada, n=1). Otros patógenos abortivos fueron identificados por métodos moleculares (virus de la diarrea viral bovina 1i y 2b, C. jejuni) o serológicos (Leptospira spp.) aunque no se cumplió con el criterio establecido para atribuir causalidad abortiva. No se identificaron ácidos nucleicos de otros protozoarios apicomplejos (N. caninum, Sarcocystis spp.), ni de Chlamydia spp., Coxiella burnetii, ni virus de la enfermedad de la frontera en ninguno de los abortos analizados. Para el tercer objetivo se evaluó la sensibilidad a ocho antimicrobianos en dos cepas de Campylobacter fetus subesp. fetus aislados de dos fetos abortados en distintos predios y en distintos años (únicos casos de aborto de etiología bacteriana identificados en el objetivo 2) y se encontró que ambas eran resistentes al ácido nalidíxico y sensibles a los otros siete antibióticos evaluados. Finalmente, el cuarto objetivo comprendió el análisis serológico de ovinos de 13 majadas mediante kits comerciales de ELISA para detección de IgG anti-T. gondii (n=364), anti-C. abortus (n=364), anti-C. burnetii (n=183) y anti-B. ovis (n=168). El porcentaje de seropositividad a nivel predial fue de 53,85% (7/13), 16,67% (2/12), 16,67% (2/12), y 0% (0/8) para T. gondii, C. abortus, C. burnetii y B. ovis, respectivamente. La seroprevalencia real general individual para T. gondii, C. abortus y C. burnetii fue 19,7% (IC95% 15,5 – 23,8), 1,3% (IC95% 0,12 – 2,42) y -5,42% (IC95% - 8,70 – -2,14), respectivamente. En conjunto, los resultados sugieren que la toxoplasmosis y la campilobacteriosis son importantes enfermedades causales de abortos en esta población de estudio, siendo además zoonóticas, mientras que la distocia es una importante causa no infecciosa de muerte fetal. A su vez, la toxoplasmosis presentó una prevalencia individual y predial relativamente alta. Son necesarios más estudios sobre la epidemiología, impacto económico, prevención y control de las enfermedades reproductivas ovinas. Asimismo, se destaca la necesidad de implementar programas de vigilancia de enfermedades zoonóticas de rumiantes en Uruguay
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
Bacterial, protozoal and viral abortions in sheep and goats in South America: A review.
Full text linkBacterial, protozoal and viral diseases are major causes of abortion in sheep and goats. These agents cause significant economic losses, and many are considered of concern for public health (zoonotic pathogens) and/or the international trade of livestock, such as those causing diseases notifiable to the World Organization of Animal Health (OIE). In South America, information about their occurrence, prevalence and economic impact is scarce. We review the available literature on bacterial, protozoal and viral abortifacients identified through laboratory testing in sheep and goats in South America and discuss whether the diagnostic investigations are conclusive in demonstrating abortion causality. We also compile information on diagnostic methods recommended by the OIE for the laboratory diagnosis of these abortifacients and on salient fetoplacental lesions induced by them. Campylobacteriosis (Campylobacter fetus subsp. fetus), listeriosis (Listeria ivanovii), chlamydiosis (Chlamydia abortus), toxoplasmosis, neosporosis and sarcocystiosis have been confirmed as small ruminant abortifacients in this region. Brucella ovis, Brucella melitensis, Campylobacter jejuni, Chlamydia pecorum, Coxiella burnetii, Leptospira spp., Bacillus licheniformis and bluetongue virus, are probable causes of abortion in the region since they have been detected in aborted fetuses and/or associated with abortions through seroepidemiologic studies. Listeria monocytogenes, Histophilus ovis, Actinobacillus seminis, Trueperella pyogenes, Yersinia spp., Trypanosoma vivax, caprine herpesvirus 1 and pestiviruses also infect small ruminants in the region and could thus be considered possible causes of abortion, although they have not been associated with abortion in South America (i.e., not detected in aborted fetuses nor associated with abortion through seroepidemiologic studies). Other agents such as Flexispira rappini, Francisella tularensis, Anaplasma phagocytophilum, Rift Valley fever virus, Wesselbron disease virus and bunyaviruses, known to be abortifacients for sheep and goats in other regions of the world, have not been documented in South America. While some of these agents could be exotic in this subcontinent, others may have been undiagnosed considering the limitations of active animal disease surveillance systems, which hamper the eventual detection of emerging, re-emerging, and communicable diseases in South America.EEA BalcarceFil: Dorsch, Matías A. Instituto Nacional de Investigación Agropecuaria (INIA). Estación Experimental La Estanzuela; Uruguay.Fil: Cantón, Germán José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Driemeier, David. Universidade Federal do Rio Grande do Sul; Brasil.Fil: Anderson, Mark. University of California; Estados Unidos.Fil: Moeller, Robert. University of California; Estados Unidos.Fil: Giannitti, Federico. Instituto Nacional de Investigación Agropecuaria (INIA). Estación Experimental La Estanzuela; Uruguay
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
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A review of cardiac blackleg in cattle, and report of 2 cases without skeletal muscle involvement in Argentina
Full text linkBlackleg is an infectious disease caused by Clostridium chauvoei. Cardiac blackleg has been reported in ruminants as an uncommon presentation of the disease; its pathogenesis is not understood completely. We include here a literature review of cardiac blackleg and a description of 2 cases in 12–15-mo-old feedlot steers in Argentina. Fourteen of 1,190 steers died suddenly over a period of 10 d. Postmortem examinations were performed on 5 of these animals. Grossly, severe, diffuse, fibrinous pericarditis and pleuritis, multifocal necrohemorrhagic myocarditis, diffuse pulmonary congestion, mild splenomegaly, and moderate congestion of meningeal vessels were observed. No significant gross lesions were observed in the skeletal muscles of any animal. Histology was performed on 2 of the steers. The main microscopic features were necrotizing myocarditis with myriad intralesional gram-positive rods with subterminal spores plus fibrinosuppurative pericarditis and pleuritis. C. chauvoei was detected by immunohistochemistry and PCR in the myocardium of both animals. These findings confirm a diagnosis of cardiac blackleg in these 2 steers and presumptively in the other affected animals.EEA BalcarceFil: Morrell, Eleonora Lidia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Odriozola, Ernesto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Dorsch, Matías A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Dorsch, Matías A. Instituto Nacional de Investigación Agropecuaria. La Estanzuela; Uruguay.Fil: Fiorentino, María Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Fiorentino, María Andrea. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Rivera, María E. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Poppenga, Robert.University of California. School of Veterinary Medicine; Estados Unidos.Fil: Navarro, Mauricio A. University of California. School of Veterinary Medicine. California Animal Health and Food Safety Laboratory System; Estados Unidos.Fil: Navarro, Mauricio A.Universidad Austral de Chile. Facultad de Ciencias Veterinarias. Instituto de Patología Animal; Chile.Fil: Uzal, Francisco A. University of California. School of Veterinary Medicine. California Animal Health and Food Safety Laboratory System; Estados Unidos.Fil: Cantón, Germán José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina
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