Fermentation Parameters of Kikuyu Grass (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) by \u3cem\u3ein Vitro\u3c/em\u3e Gas Production Technique (IVGPT)

Methane (CH4) is a byproduct of ruminal fermentation whose production is directly related to forage quality, which in turn is affected by a myriad of environmental factors. In general the quality of pastures in the tropics range from medium to poor due to a high content of lignocellulosic material of low digestibility and a low content of other components, such as soluble carbohydrates and protein (Correa et al, 2008). CH4 produced by enteric fermentation from cattle rumen represents a major source of greenhouse gases (GHG). By measuring these emissions the impact of dairy production systems on the climate change can be determine. In Colombia and in specifically in the Department of Antioquia, dairy herds are characterized by using diets based on kikuyu grass (Pennisetum clandestinum) supplemented with concentrates. Once in the rumen the forage /concentrate combination are used as substrate for ruminal fermentation to generate usable energy but also unusable one represented by methane production. The energy losses due to diets based on kikuyu are unknown. Thus, the measurement of its fermentation products has become an important necessity in order to achieve greater efficiencyin the livestock production systems which are also environmentally friendly and economically competitive. Despite some important progress in Colombia, the potential impact of livestock on global warming is still unknown so that measuring of CH4 emissions is a crucial imperative. In the dairy zone located in the northern part of Antioquia, where daily two millions liters of milk are produced, there are around 185,000 ha in kikuyu pasture. The overall objective of this research was to measure the parameters of fermentation and CH4 production of kikuyu pastures from dairy systems of Antioquia, using the in vitro gas production technique (IVGPT)

Effects of Different Feed Additives on Methane Emissions from Beef Cattle

The rate of accumulation of methane in the atmosphere from enteric fermentation in cattle has an important impact on the greenhouse effect and contributing to global warming. Additionally, methane emission reduces the energy efficiency of substrate fermention in the rumen. Under-standing the effect of the diet on enteric methane emissions could help to identify strategies to reduce emissions of this greenhouse gas. Therefore, the main objective of the present investigation was to determine the effect of nutritional additives such as monensin, fumaric acid, tannins of Acacia decurrens, and glycerol on methane production and other measures of fermentation characteristics using the in vitro rumen fermentation technique and ruminal fluid obtained from cattle fed with a base diet of Pennisetum clandestinum

Las ontologías en la ingeniería de software: un acercamiento de dos grandes áreas del conocimiento

Los conceptos ontológicos se suelen acercar más a la ingeniería del conocimiento, por lo que los ingenieros del software no los suelen aplicar para resolver problemas de su área. Es necesario que los ingenieros de software se apropien de las ontologías, pues éstas proporcionan un vocabulario común, que podría contribuir en la solución de problemas recurrentes en ingeniería del software, tales como la dificultad de la comunicación entre analista e interesado para definir los requisitos de un sistema, la baja reutilización de componentes y la escasa generación automática de código, entre otros. En este artículo se presenta un primer enlace entre las ontologías y la ingeniería de software mediante la recopilación y análisis de la literatura relativa a la utilización de las ontologías en las diferentes fases del ciclo de vida de un producto de software

Análisis competitivo del sector de las mipymes distribuidoras de calzado en la ciudad de Cartagena

Es evidente que la globalización ha impuesto cambios inexorables en la actividad económica y empresarial colombiana. En el contexto de la economía abierta, la expansión económica ha generado nuevos sectores y desestructuró otros que rápidamente se rezagan y pierden competitividad. Por tanto, en un contexto económico caracterizado por cambios rápidos y complejos, donde la competitividad y la calidad son un imperativo, las organizaciones cada vez tienen mayor necesidad de iniciar rápida y eficazmente cambios alterando sus estructuras empresariales vigentes, para facilitar la incorporación de esquemas de modernización organizativa, acordes con las exigencias del mercado. Con relación al sector comercial se puede hablar de un ambiente en donde las empresas ya han tomado la decisión de modernizarse o tienen claro un referente de modernización administrativa y tecnológica; sin embargo, estudios sobre la innovación en las organizaciones industriales de Colombia muestran que 1 , si bien los directivos expresan una fuerte convicción por la necesidad de cambio y dicen estar comprometidos con éste, los resultados indican que tal compromiso dista mucho de ser llevado a la práctica. Este es el caso de las empresas que conforman las Mipymes distribuidoras de calzado en la ciudad de Cartagena, que a pesar de ser considerado como un sector importante del comercio local, sus negocios todavía necesitan una gran dosis de innovación que les permita desenvolverse en un ambiente de competitividad, tecnología e información, si quieren permanecer siendo competitivas en el mercado. Esta necesidad se ha venido ventilando y concretando recientemente, pues dadas las nuevas reglas de juego en el ámbito nacional y mundial, los modelos tradicionales de competitividad diseñados para manejar la complejidad, no son una respuesta para producir el cambio que requieren

Treatment of tropical forages with exogenous fibrolytiic enzymes: effects on chemical composition and in vitro rumen fermentation

The effects of three treatments of fibrolytic enzymes (cellulase from Trichoderma longibrachiatum (CEL), xylanase from rumen micro-organisms (XYL) and a 1:1 mixture of CEL and XYL (MIX) on the in vitro fermentation of two samples of Pennisetum clandestinum (P1 and P2), two samples of Dichanthium aristatum (D1 and D2) and one sample of each Acacia decurrens and Acacia mangium (A1 and A2) were investigated. The first experiment compared the effects of two methods of applying the enzymes to forages, either at the time of incubation or 24 h before, on the in vitro gas production. In general, the 24 h pre-treatment resulted in higher values of gas production rate, and this application method was chosen for a second study investigating the effects of enzymes on chemical composition and in vitro fermentation of forages. The pre-treatment with CEL for 24 h reduced (p < 0.05) the content of neutral detergent fibre (NDF) of P1, P2, D1 and D2, and that of MIX reduced the NDF content of P1 and D1, but XYL had no effect on any forage. The CEL treatment increased (p < 0.05) total volatile fatty acid (VFA) production for all forages (ranging from 8.6% to 22.7%), but in general, no effects of MIX and XYL were observed. For both P. clandestinum samples, CEL treatment reduced (p < 0.05) the molar proportion of acetate and increased (p < 0.05) that of butyrate, but only subtle changes in VFA profile were observed for the rest of forages. Under the conditions of the present experiment, the treatment of tropical forages with CEL stimulated their in vitro ruminal fermentation, but XYL did not produce any positive effect. These results showed clearly that effectiveness of enzymes varied with the incubated forage and further study is warranted to investigate specific, optimal enzyme-substrate combinations

Digitally Continuous Multivalued Functions, Morphological Operations and Thinning Algorithms

In a recent paper (Escribano et al. in Discrete Geometry for Computer Imagery 2008. Lecture Notes in Computer Science, vol. 4992, pp. 81–92, 2008) we have introduced a notion of continuity in digital spaces which extends the usual notion of digital continuity. Our approach, which uses multivalued functions, provides a better framework to define topological notions, like retractions, in a far more realistic way than by using just single-valued digitally continuous functions. In this work we develop properties of this family of continuous functions, now concentrating on morphological operations and thinning algorithms. We show that our notion of continuity provides a suitable framework for the basic operations in mathematical morphology: erosion, dilation, closing, and opening. On the other hand, concerning thinning algorithms, we give conditions under which the existence of a retraction F:X⟶X∖D guarantees that D is deletable. The converse is not true, in general, although it is in certain particular important cases which are at the basis of many thinning algorithms

Quantum point contact conductance in NINS junctions

The effect of an insulating barrier located at a distance $a$ from a NS quantum point contact is analyzed in this work. The Bogoliubov de Gennes equations are solved for NINS junctions (S: anysotropic superconductor, I: insulator and N: normal metal), where the NIN region is a quantum wire. For $a\neq0$, bound states and resonances in the differential conductance are predicted. These resonances depend on the symmetry of the pair potential, the strength of the insulating barrier and $a$. Our results show that in a NINS quantum point contact the number of resonances vary with the symmetry of the order parameter. This is to be contrasted with the results for the NINS junction, in which only the position of the resonances changes with the symmetry.Comment: 5 pages, 5 Figures, RevTex