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San Carlos del Zulia, Venezuela

Bordera S.,University of Alicante | Mazon M.,National Experimental University of Sur del Lago | Mazon M.,University of Los Andes, Venezuela
Zootaxa | Year: 2015

The aim of this paper is to describe and illustrate a new species of Aclastus with dimorphic females and to provide the diagnostic characters to distinguish it from Holarctic species of the genus. In addition, we provide data on the habitat and phenology of the species. Copyright © 2015 Magnolia Press.

Gonzalez-Pedraza A.F.,National Experimental University of Sur del Lago | Gonzalez-Pedraza A.F.,Venezuelan Institute for Scientific Research | Dezzeo N.,Venezuelan Institute for Scientific Research
Scientific World Journal | Year: 2014

We evaluated changes of different soil nitrogen forms (total N, available ammonium and nitrate, total N in microbial biomass, and soil N mineralization) after conversion of semideciduous dry tropical forest in 5- and 18-year-old pastures (YP and OP, resp.) in the western Llanos of Venezuela. This evaluation was made at early rainy season, at end rainy season, and during dry season. With few exceptions, no significant differences were detected in the total N in the three study sites. Compared to forest soils, YP showed ammonium losses from 4.2 to 62.9% and nitrate losses from 20.0 to 77.8%, depending on the season of the year. In OP, the ammonium content increased from 50.0 to 69.0% at the end of the rainy season and decreased during the dry season between 25.0 and 55.5%, whereas the nitrate content increased significantly at early rainy season. The net mineralization and the potentially mineralizable N were significantly higher P < 0.05 in OP than in forest and YP, which would indicate a better quality of the substrate in OP for mineralization. The mineralization rate constant was higher in YP than in forest and OP. This could be associated with a reduced capacity of these soils to preserve the available nitrogen. © 2014 Ana Francisca González-Pedraza and Nelda Dezzeo.

Uzcategui D.,National Experimental University of Sur del Lago | Angulo-Cubillan F.,University of Zulia | Gil M.,University of Zulia | Ramirez A.,Technical University Territorial Of Maracaibo | And 3 more authors.
Revista Cientifica de la Facultad de Ciencias Veterinarias de la Universidad del Zulia | Year: 2014

Buffaloes (Bubalus bubalis) are animals of great importance in the production of animal-derived food in Venezuela. Despite their adaptability and relative resistance to diseases, there are a number of helminthes that could infect them. Moniezia spp. are the species of cestodes of greatest importance in buffaloes, affecting mainly young animals. A descriptive cross-sectional research was conducted to determine the prevalence of Moniezia spp. infection in buffaloes from Colon County of Zulia State. Five hundred and twelve feces samples from five farms (A, B, C, D, and E) were analyzed through the flotation method using a saturated sodium chloride solution. Animals were classified according to their age as follows • 3 months old (I); > three months old to a year old (II); > a year old to two years old (III), and > two years old (IV). Data were analyzed through the statistical analysis software SAS, using Chi-squared test. General prevalence for Moniezia spp. was 4.7%, and for Moniezia benedeni and Moniezia expansa, were 4.1 and 0.6%, respectively. Prevalences at farm level showed a statistically significant association (P<0.05), with 1.8, 6.7, 11.1, 0.5, and 8.6% at farm A, B, C, D, and E, respectively. M.expansa was only detected at farm C. As for age category, prevalences were 8.42, 6.42, 6.72, and 0% for categories I, II, III, and IV, respectively, showing a statistically significant association (P<0.05). In conclusion, Moniezia spp. are cestodes present in all assessed buffaloes farms, with a higher prevalence for M. benedeni. Buffaloes age affects the prevalence of the infection, being it higher in animals younger than three months old. Moniezia spp. eggs in feces from animals older than two years old were not observed.

Gonzalez-Pedraza A.F.,National Experimental University of Sur del Lago | Rey J.C.,Instituto Nacional Of Investigaciones Agricolas Inia | Atencio J.L.P.,National Experimental University of Sur del Lago
Revista de la Facultad de Agronomia | Year: 2014

A systematic sampling directed with geo-referenced points spaced every 100 m or so was used to evaluate the spatial variability of sand (%Sa), silt (%Si), clay (%C), organic matter (%OM), and pH in soils of the experimental unit The Glorieta for agricultural purposes. Classical statistics was applied to build semivariograms geo-statistical which were used by “Kriging” interpolation to characterize the variability of the sector. The spatial variation of the properties evaluated was from medium to low, with a spatial dependence between 347.3 and 469.7 m and a variance random between 0 and 77.83%. There was a strong spatial dependence in %L, pH and %OM, moderate to weak for %Sa and %C. The soil particle size showed greater variation from east to west, while pH and %OM varied more from north-south. These results provide a basis for experimental site location and selection of appropriate crops for the farm. © 2014, Universidad del Zulia. All rights reserved.

Gonzalez Y.G.H.,National Experimental University of Sur del Lago | Nino C.Y.P.,National Experimental University of Sur del Lago
Revista de la Facultad de Agronomia | Year: 2014

Gerbera is one of the most important flower crops in the world. Its propagation is done almost exclusively through the in vitro culture technique, microbial contamination being the first barrier to the reproduction of this species. For this reason, to establish an effective method of disinfecting gerbera 100 flower sections belonging to varieties Antibes and Ross Roills were washed with blue commercial soap blue and disinfectants twice for 10 min with NaOCl (20%). Then, 25 capitulum for each variety were dipped into HgCl2 (0.1% W/V) for 10 min (D1). The rest were dipped but again in NaClO for 5 min but at 10% V/V (D2). All explants were placed on solid medium (pH 5, 8) consisting of MS salts, 2 mg.L-1 BAP, adenine sulfate, 80 mg.L-1, 0,5 mg.L-1 of AIB, sucrose 30 g.L-1 and 20 ppm citric acid. The rooting of the shots was done using a medium with ½MS, 5 mg.L-1AIA, 20 g of sucrose and 0.5 g of activated charcoal. The variables studied were contaminated and oxidized explants, callus number, shoots and plant survival. The Antibes variety was the only one that did not present microbial contamination by 40% of the floral capitulum with the D1 method, generating white friable callus, shoots and normal plants. This method of disinfection could be considered as viable for in vitro propagation of Gerbera. © 2014, Universidad del Zulia. All rights reserved.

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