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Cundinamarca, Colombia

The University of Cundinamarca , is a public, departmental, coeducational university located primarily in the city of Fusagasugá in Cundinamarca, Colombia. The university has satellite campuses across the department in the cities of Chía, Chocontá, Facatativá, Girardot, Soacha, Ubaté and Zipaquirá. Wikipedia.

Guerrero E.R.,University of Cundinamarca | Benavides G.M.,University of San Buenaventura
2014 IEEE Colombian Conference on Communications and Computing, COLCOM 2014 - Conference Proceedings | Year: 2014

Farming of Hass-variety-avocado has become an important economic activity in Colombian agriculture for covering local market requirements but also for exporting high quality fruits to foreign markets. Many processes still need to be improved in different regions of Colombia where Hass variety is cultivated in order to increase the efficiency during harvesting, transportation and storage. Human-performed classification of avocados takes time that could be used by farm's personnel to perform other activities aimed to achieve higher quality standards and production efficiency. Product price and target market depends to a large extent on classification stage. We propose a system based on image processing of avocados' pictures for their classification after they have been picked off the tree. The classifying algorithm runs on a computer which receives fruit's images wirelessly from a camera, the result is transmitted using IEEE 802.15.4 packets and avocados are placed in conveyor belt rails according to their categories. Matching percentage of the image processing algorithm for selecting avocados was of 88% compared to the test set classified by expert farmers. Confusion matrix showed 82.22% accuracy when classifying avocados. © 2014 IEEE. Source

Orjuela-Matta H.M.,University of Cundinamarca | Sanabria Y.R.,National University of Colombia | Camacho-Tamayo J.H.,National University of Colombia
Chilean Journal of Agricultural Research | Year: 2012

Studies that involve soil attributes variability help the analysis of the behavior of hydrophysical attributes in space, to support the decision-making process within the conception of precision agriculture. The aim of the present paper was to characterize the spatial variability of the surface infiltration and its relation to some soil physical attributes. The sampling was done with a rectangular mesh of 64 points with perpendicular distances of 52 m × 45 m between sampling points. The attributes studied were bulk density, contents of sand, silt and clay, soil moisture, cumulative infiltration, basic infiltration, sorptivity, and saturated hydraulic conductivity (Ks). Data were analyzed using descriptive statistics and geostatistics, identifying the relationship between attributes, using the Pearson correlation and cluster analysis. Results suggest a behavior of parameters close to normal, attributes related to soil water movement had greater variability, with low basic infiltration (1.46 cm h-1) and Ks (0.80 cm h-1), which together with high values of bulk density (1.87 g cm-3) show limitations by compaction. Cumulative infiltration and Ks attributes did not fit to models of spatial distribution, finding ranges of 150 m for the other attributes, distance to optimize future sampling for the study of spatial variability. Pearson correlation and cluster analysis allowed establishing relationships between soil attributes; spatial relationships were corroborated in contour maps, where we observed the influence of clay and sand content in the behavior of bulk density, and the influence of these attributes in processes of water infiltration into the soil. Source

Li G.,Chinese Academy of Agricultural Sciences | Li G.,Henan Academy of Agricultural science | Feng H.,Henan Academy of Agricultural science | Gao Y.,Chinese Academy of Agricultural Sciences | And 2 more authors.
Environmental Entomology | Year: 2010

Helicoverpa armigera Hbner (Lepidoptera: Noctuidae) is a key insect pest of cotton in Xinjiang cotton-planting region of northwest China. In this region, cotton is grown on average ∼1.65 million ha (1.53∼1.80 million ha) annually in largely monoculture agricultural landscapes, similarly to cropping systems in the United States or Australia. Under such cropping regimes, naturally occurring refuges (with non-Bt crops) may be insufficient to prevent H. armigera resistance development to Bt toxins. Therefore, we assessed frequency of alleles conferring resistance to Cry1Ac toxin of F1 and F2 offspring of H. armigera isofemale lines from two distinct localities in the region during 2005-2009. More specifically, a total of 224 isofemale lines was collected from Korla County (≈70% Bt cotton adoption) and 402 lines from Shache County (≈5% Bt cotton planting). Subsequent offspring was screened on Cry1Ac artificial diet. From 2005 to 2009, resistance gene frequency in Korla fluctuated between 0.0000 and 0.0040, while being 0.0000-0.0008 in individuals collected from Shache, and there were no significant increases in both counties from 2005 to 2009. Relative average development rates (RADRs) of larvae in F1 tests showed significant increases from Korla, but not in Shache. RADR of F1 larvae is significantly correlated with RADR of F2 offspring, indicating genetic variation in response to toxin in field H. armigera population. Although the occurrence of Cry1Ac resistance alleles was low in Xinjiang cotton-planting region of China, particular attention should be given to H. armigera resistance development in Korla County. © 2010 Entomological Society of America. Source

Acero A.,University of Cundinamarca | Muir J.P.,Texas AgriLife Research Center | Wolfe R.M.,Texas AgriLife Research Center
Journal of the Science of Food and Agriculture | Year: 2010

The role of condensed tannins (CT) in ruminant nutrition and health makes changes in leaf litter (LL) after abscission of interest. This study compared the effect of different drying methods of green leaves (GL) with that of natural drying of LL on CT, fibre, crude protein (CP) and phosphorus (P) concentrations in nine Texas browse species. Leaves harvested before autumn shedding were oven-dried (OD) or freeze-dried (FD). RESULTS: Where different (P < 0.05), extractable CT concentrations were higher while protein- and fibre-bound CT concentrations were lower in GL-FD than in LL. Drying method changed total CT concentration in three species. Where different, fibre fraction concentrations were greater in LL than in GL, regardless of drying method. In some species, CP and P concentrations were lower in LL than in GL, but in five species they did not change (P > 0.05) from GL to LL, with CP concentrations ranging from 63 to 151 g kg-1 in the latter. CONCLUSION: Browse LL had high nutritive value and CT concentrations, explaining why browsing ruminants utilise this feed resource. However, changes in nutrient and CT concentrations as leaves become litter in some species mean that information on one is not necessarily applicable to the other. © 2010 Society of Chemical Industry. Source

Hernandez-Fernandez J.,Jorge Tadeo Lozano University, Bogota | Ramirez L.,Jorge Tadeo Lozano University, Bogota | Ramirez N.,Jorge Tadeo Lozano University, Bogota | Fuentes L.S.,University of Cundinamarca | Jimenez J.,University of Cundinamarca
World Journal of Microbiology and Biotechnology | Year: 2011

Twenty-eight soil samples were obtained from open fields and greenhouses used for tomato cultivation in various regions of Colombia. For functional characterization, 99 Bacillus thuringiensis (Bt) strains were isolated and characterized by abundance and morphology of microscopic crystals, SDS-PAGE of protein extracts and M-PCR analyses of genes of the cry1 family, as well as for their insecticidal activity against Tuta absoluta second instar larvae. Native Bt strains had amorphous (5%), bi-pyramidal (27%), square (8%), spherical (38%) and triangular (22%) crystal forms. Based on the presence of 1-4 different crystal forms, 18 different profiles were established. The SDS-PAGE analyses of protein extracts established ten different strain groups based on their protein band weight and potential biological activity. The M-PCR technique identified 35 native Bt strains based on the presence of the 6 genes cry1Aa, cry1Ab, cry1Ac, cry1B, cry1C and cry1D, whose frequency of occurrence was 76, 26, 21, 35, 32 and 8.8%, respectively. Thirteen different PCR profiles were found in native Bt strains. Several gene combinations tended to co-occur with elevated frequency, such as the pairs cry1Ac/cry1C, cry1Ab/cry1Ac and cry1Ab/cry1B, for which Pearson correlation coefficients were 0.69, 0.52 and 0.54, respectively. Native strains ZBUJTL39 and ZCUJTL11 had up to three times higher biological activity against T. absoluta second instar larvae than the reference strain Bt var. kurstaki HD1, with an LD50 of 2.4 μg/ml (P<0.05) for native Bt strain ZCUJTL11. This study suggests a high biodiversity of native Bt strains from tomato growing regions in Colombia, which has important implications for designing biological control strategies for T. absoluta. © 2010 Springer Science+Business Media B.V. Source

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