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Dynamics of the ruminal microbial ecosystem, and inhibition of methanogenesis and propiogenesis in response to nitrate feeding to Holstein calves

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Animal Nutrition 2021年第4期7卷 1205-1218页

作者： abimael ortiz-chura Jose Gere Gisela Marcoppido Gustavo Depetris Silvio Cravero Claudia Faverin Cesar Pinares-Patino Angel Cataldi d Maria E.Ceron-Cucchi Institute of Pathobiology CICVyA National Institute of Agricultural TechnologyIPVetUEDD INTA-CONICETHurlinghamC1686Argentina Engineering Research and Development Division National Technological University(UTN)National Scientific and Technical Research Council(CONICET)Buenos AiresC1179Argentina Agricultural Experimental Station of Balcarce National Institute of Agricultural Technology(INTA)BalcarceB7620Argentina Institute of Agrobiotechnology and Molecular Biology IABIMONational Institute of Agricultural Technology(INTA)National Scientific and Technical Research Council(CONICET)HurlinghamC1686Argentina The Agribusiness Group Lincoln UniversityPO Box 85016Lincoln7674New Zealand

It is known that nitrate inhibits ruminal methanogenesis,mainly through competition with hydrogenotrophic methanogens for available hydrogen(H2)and also through toxic effects on the ***,there is limited knowledge about its effects on the others members of ruminal microbiota and their *** this study,we investigated the effects of dietary nitrate inclusion on enteric methane(CH4)emission,temporal changes in ruminal microbiota,and fermentation in Holstein *** animals were maintained in individual pens for 45 *** were randomly allocated to either a control(CTR)or nitrate(NIT,containing 15 g of calcium nitrate/kg dry matter)*** emissions were estimated using the sulfur hexafluoride(SF6)tracer *** microbiota changes and ruminal fermentation were evaluated at 0,4,and 8 h *** this study,feed dry matter intake(DMI)did not differ between dietary treatments(P>0.05).Diets containing NIT reduced CH4 emissions by 27%(g/d)and yield by 21%(g/kg DMI)compared to the CTR(P0.05)but differed with time,and post-feeding(P<0.05).Increases in the concentrations of ruminal ammonia nitrogen(NH3-N)and acetate were observed,whereas propionate decreased at 4 h post-feeding with the NIT diet(P<0.05).Feeding the NIT diet reduced the populations of total bacteria,total methanogens,Ruminococcus albus and Ruminococcus flavefaciens,and the abundance of Succiniclasticum,Coprococcus,Treponema,Shuttlewortia,Succinivibrio,Sharpea,Pseudobutyrivibrio,and Selenomona(P<0.05);whereas,the population of total fungi,protozoa,Fibrobacter succinogenes,Atopobium and Erysipelotrichaceae L7 AE11 increased(P<0.05).In conclusion,feeding nitrate reduces enteric CH4 emissions and the methanogens population,whereas it decreases the propionate concentration and the abundance of bacteria involved in the succinate and acrylate pathways.D

关键词： Methane emission Nitrate Microbiota Ruminal fermentation

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Weighted Interior Penalty Methodwith Semi-Implicit Integration Factor Method for Non-Equilibrium Radiation Diffusion Equation

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Communications in Computational Physics 2013年第10期14卷 1287-1303页

作者： Rongpei Zhang Xijun Yu Jiang Zhu abimael F.D.Loula Xia Cui School of Sciences Liaoning ShiHua UniversityFushun 113001China Laboratory of Computational Physics Institute of Applied Physics and ComputationalMathematicsBeijing 100088China Laborat´orio Nacional de Computa¸cao Cient´ıfica MCTIAvenida Get´ulio Vargas33325651-075 Petr´opolisRJBrazil

Weighted interior penalty discontinuous Galerkin method is developed to solve the two-dimensional non-equilibrium radiation diffusion equation on unstructured *** are three weights including the arithmetic,the harmonic,and the geometric weight in the weighted discontinuous Galerkin *** the time discretization,we treat the nonlinear diffusion coefficients explicitly,and apply the semiimplicit integration factormethod to the nonlinear ordinary differential equations arising from discontinuous Galerkin spatial *** semi-implicit integration factor method can not only avoid severe timestep limits,but also takes advantage of the local property of DG methods by which small sized nonlinear algebraic systems are solved element by element with the exact Newton iteration *** results are presented to demonstrate the validity of discontinuous Galerkin method for high nonlinear and tightly coupled radiation diffusion equation.

关键词： Discontinuous Galerkin weighted interior penalty semi-implicit integration factor non-equilibrium radiation diffusion

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Dam Breach Analysis Using HEC-RAS and HEC-GeoRAS: The Case of Kesem Kebena Dam

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Open Journal of Modern Hydrology 2019年第4期9卷 113-142页

作者： abimael Leoul Nebiyou Kassahun Hydraulic Engineering Department Institute of Technology College Debre Markos University Debre Markos Ethiopia

Ethiopia has been booming with active construction of dams within the past few decades for different infrastructural needs, but has never experienced demolition or failure of dams in its history;hence little attention is being given to possible breach scenarios of dams and the resulting floodings. This paper makes analysis of the possible breach of kesem dam and the resulting flood inundation. In this study, the dam has been checked for both overtopping and piping failure modes using one dimensional river analysis model called HEC-RAS. Empirical equations were used to predict dam breach parameters of the two failure modes for use in this model. PMF inflow with a peak 9237.77 m3/s is used as an input to the reservoir to check if overtopping failure was possible. The spill way has proven to have adequate capacity for the flood due to the PMF. Therefore, breaching of the embankment was not possible. Piping failure was also simulated in HEC-RAS and the resulting breach due to piping failure, was analyzed and flood hydrograph was obtained at different cross sections along the river. These are flood hydrographs at 20 km, 40 km and 60 km at the downstream. The resulting flood plain was also mapped using HEC-GeoRas to show the extent of flooding.

关键词： Dam Breach Analysis Flood Mapping HEC-RAS HEC-GeoRAS

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A FINITE ELEMENT SOLVER FOR NAVIER-STOKES EQUATIONS VIA VORTICITY AND VELOCITY

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Transactions of Nanjing University of Aeronautics and Astronautics 2001年第Z1期18卷 115-118页

作者： Zhu Jiang abimael F D Loula Laboratório Nacional de Computaco Científica, MCT,Av Getúlio Vargas 333, 25651 070 Petrópolis, RJ, Brazil Laboratório Nacional de Computacao Cientifica MCTAy Getulio Vargas 333 25651-070 Petrópolis R J Brazil

The incompressible Navier Stokes equations are solved via variables of vorticity and velocity. Firstly, a rigorous variational framework with the equivalence between the velocity pressure and the vorticity velocity formulations is presented in a Lipschitz domain. Next, a class of Galerkin finite element approximations of the corresponding variational form is introduced, and a convergence analysis is given for the Stokes problem. Finally, an iterative finite element solver for the Navier Stokes problem is proposed.

关键词： incompressible Navier-Stokes equations vorticity-velocity formulation finite element approximations convergence analysis

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