Semen variables of sheep (Ovis aries) experimentally infected with Toxoplasma gondii

The influence of Toxoplasma gondii on semen variables and sperm morphology of sheep was evaluated in eight reproductive males distributed into three experimental groups: GI, three sheep inoculated with 2.0 × 105 of P strain oocytes; GII, three sheep infected with 1.0 × 106 of RH strain tachyzoites and; GIII two control sheep. Clinical (rectal temperature, cardiac and respiratory frequencies), parasite and serology exams (IIF) were realized. Sperm variables (volume, motility, vigor and concentration) and semen morphology for each sheep were also evaluated. Thus, semen and blood collections were assessed on post-inoculation days (PIDs)-1,3,5,7,11,14 and weekly thereafter up to PID 70. Clinical alterations were observed (hypothermia and anorexia) in infected sheep from groups GI and GII. Parasitic outbreaks were detected in five sheep. All the infected sheep produced antibodies against T. gondii from PID 5 onwards, reaching a peak of 4096 and 8192 for group GI and GII sheep, respectively. Differences (P < 0.05) were observed regarding the ejaculate volume between the inoculated groups (oocytes and tachyzoites) and control. Even though experimental toxoplasmic infection resulted in clinical symptomology in the inoculated sheep, the minimal alterations in sperm pathologies could not be directly attributed to T. gondii. © 2008 Elsevier B.V. All rights reserved.

Actualizar las variables de la integración latinoamericana

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Climatic variables and altitude as predictors of anuran species richness and number of reproductive modes in Brazil

Because anuran species are highly dependent on environmental variables, we hypothesized that anuran species richness and the number of reproductive modes from different Brazilian localities vary according to climatic and altitudinal variables. Published data were compiled from 36 Brazilian localities and climatic and altitudinal data were extracted from an available database. A partial redundancy analysis (pRDA) showed that 23.5% of the data set's variation was explained by climatic and altitudinal data, while the remaining 76.5% remained unexplained. This analysis suggests that other factors not analysed herein may also be important for predicting anuran species richness and the number of reproductive modes in Brazil. Altitude and total annual rainfall were positively correlated with anuran species richness and the number of reproductive modes, and total annual rainfall was strongly associated with these two biotic variables in the triplot of pRDA. The positive association of total annual rainfall and the negative association of the concentration of annual rainfall were already expected based on physiological and reproductive requirements of anurans. On the other hand, temperature was not associated with richness or the number of reproductive modes. Copyright © 2010 Cambridge University Press.

La influencia de las variables financieras sobre las exportaciones bajo un régimen de racionamiento de crédito: una aproximación teórica y su aplicación al caso chileno

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Variables extrapedagógicas y equidad en la educación media: hogar, subjetividad y cultura escolar

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Actualizar las variables de la integración latinoamericana

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América Latina: las variables económicas de los censos de población de la ronda del 2000

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Estimación de población en áreas menores mediante variables sintomáticas: una aplicación para los departamentos de la República Argentina, 1991 y 1996

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Panamá: la mortalidad infantil según variables socioeconómicas y geográficas 1966-1976

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Influence of some intermediate variables in the level and differentials of urban and rural fertility in Latin America

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Influencia de algunas variables intermedias en el nivel y en las diferenciales de fecundidad urbana y rural de América Latina

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America Latina: analisis preliminar de la vinculacion entre algunas variables economicas y aspectos de la poblacion, 1950-1960

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Participacion de la mujer en las actividades economicas en Chile (1960): un analisis de las variables demograficas, en particular la fecundidad

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