Supplementing fructose-based block supplements to forage-fed cattle increases capacity for lactic acid metabolism

Acidosis is one of the more important maladies afflicting cattle fed significant amounts of grain and has enormous economic impact for feedlots, dairies, and producers of seed stock. The highest incidence of acidosis occurs when animals are being transitioned from high-roughage diets to diets containing high levels of concentrates. When grain-based diets are consumed in excess, consumed too quickly, or fed without proper adaptation, digestive end products (organic acids) can accumulate within the rumen, resulting in acidosis. Lactic acid is one of the key organic compounds that accumulates under these conditions. Coupled with the animal’s limited ability to metabolize lactate, accumulation of lactic acid in the rumen lowers ruminal pH and subsequently depresses feed intake. One means of preventing acidosis is to directly populate the rumen with lactate-utilizing bacteria. Alternatively, exposure to low levels of lactate (i.e., levels insufficient to harm the animal) may stimulate development of a population of lactate-utilizing bacteria. The objective of our study was to determine if supplementing low-moisture blocks made of high fructose corn syrup could increase ruminal lactate concentrations and subsequently stimulate growth of lactate-metabolizing bacteria. If successful, this could prove useful for adapting forage-fed cattle to grain-based diets

Bound states of Θ+\Theta^+ in nuclei

We study the binding energy and the width of the $\Theta^+$ in nuclei, associated to the $K N$ and $K \pi N$ components. The first one leads to negligible contributions while the second one leads to a sizeable attraction, enough to bind the $\Theta^+$ in nuclei. Pauli blocking and binding effects on the $K N$ decay reduce considerably the $\Theta^+$ decay width in nuclei and medium effects associated to the $K \pi N$ component also lead to a very small width, as a consequence of which one finds separation between the bound levels considerably larger than the width of the states.Comment: Presentation in the 10th International Baryon Conference BARYON0

Scale-invariant moving finite elements for nonlinear partial differential equations in two dimensions

A scale-invariant moving finite element method is proposed for the adaptive solution of nonlinear partial differential equations. The mesh movement is based on a finite element discretisation of a scale-invariant conservation principle incorporating a monitor function, while the time discretisation of the resulting system of ordinary differential equations is carried out using a scale-invariant time-stepping which yields uniform local accuracy in time. The accuracy and reliability of the algorithm are successfully tested against exact self-similar solutions where available, and otherwise against a state-of-the-art h-refinement scheme for solutions of a two-dimensional porous medium equation problem with a moving boundary. The monitor functions used are the dependent variable and a monitor related to the surface area of the solution manifold

Using stable isotopes to detect responses to environmental change in parapatric ctenomyid rodents

Understanding how interspecific differences in a community play out in response to historical environmental changes provides a useful foundation for predicting the evolutionary and conservation outcomes of future changes in environmental conditions. Ecological studies have increasingly utilized stable isotopes to gain insights into the diets, and hence, the floristic composition that historical populations of mammals utilized. Here, we report on the use of stable isotope analyses of rodent teeth to explore the potential role that interspecific differences in response to past environmental changes have played in shaping observed differences in genetic structure between two parapatric species of ctenomyid rodents.Fil: Takenaka, R.. University of California at Berkeley; Estados UnidosFil: Miller, M.J.. University of California at Berkeley; Estados UnidosFil: Tammone, Mauro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Lacey, E. A.. University of California at Berkeley; Estados UnidosFil: Dawson,T. E.. University of California at Berkeley; Estados Unidos96th Annual Meeting of the American Society of MammalogistsMinneapolisEstados UnidosAmerican Society of MammalogistsUniversity of Minnesot

Understanding the generation of methanol synthesis and water gas shift activity over copper-based catalysts – A spatially resolved experimental kinetic study using steady and non-steady state operation under CO/CO₂/H₂ feeds

AbstractUnderstanding the mechanism and generation of activity for methanol synthesis and the water gas shift reactions over copper-based catalysts remains a significant area of study in heterogeneous catalysis. In this work, steady and non-steady state experimental and kinetic modelling methods are presented to demonstrate changes in functionality of a Cu/ZnO/Al2O3 catalyst based on gas composition.Steady-state testing of a Cu/ZnO/Al2O3 catalyst, using experimental spatial discretisation approaches with fixed-bed, integral-operation micro reactors, has generated performance data over a range of PCO/PCO2 ratios (1–10). The data showed a mixture of observations where forward or reverse water gas shift was kinetically favourable, and also where the reaction was significantly limited by thermodynamic equilibrium. A steady state Langmuir–Hinshelwood model based on micro kinetics was most appropriate which includes kinetic descriptions of both directions of the water gas shift reaction. Using this method, the entire dataset could be predicted and an internal consistency within the kinetic model of the key adsorption constants was demonstrated.Non-steady state, ‘reactor start-up’, testing of a Cu/ZnO/Al2O3 catalyst marked a novel approach to further understanding the functionality of the catalyst. Initial changes in surface carbon and oxygen populations were quantified and linked to subsequent dynamic changes in methanol synthesis and water gas shift activity. Cu/ZnO and Cu/Al2O3 formulations were also evaluated and tested using kinetic models, permitting a structural and compositional comparison with Cu/ZnO/Al2O3