Investigating the stability of the LBM-BGK through an extended von Neumann analysis

International audienc

Investigating the stability of the LBM-BGK through an extended von Neumann analysis

International audienc

A N'Dama cattle resource population for research on trypanotolerance

The genetic components of trypanotolerance measurements must be determined in well controlled on going production systems where the necessary identification and/or quantification of environment and genetic effects are possible. A resource population has been established in the Mushie District Bandundu Province, Democratic Republic of Congo, within a commercial ranch situated in one of the highest available tsetse/trypanosomosis challenge areas having cattle. Cattle are grade N'Dama selected from an original group imported into R.D. Congo 75 years ago. Breeding cows are maintained in multi-sire herds. Parentage (sire) determination in the experimental population is done through molecular genetic markers (micro-satellites). In order to evaluate the genetic diversity within the experimental population, 50 unrelated bulls were genotyped for 33 bovine microsatellites, mapping 19 chromosomes. It was concluded that the variability of and polymorphism of, the markers in the resource population is substantial and will allow accurate parentage determination. More importantly for the relevance of the research on the within-breed genetic variation of trypanotolerance measurements, it was concluded that the resource population was one of the purest N'Dama cattle population available for research, exposed to high level of natural trypanosomosis risk, as indicated by the likely absence of introgression of Zebu type genes

IDEAS: A tool for improved evaluation and utilization of animal genetic resources

Discusses the potential of IDEAS - ILCA's Data entry and Analysis system, key for success including accuracy, rapidity & simplicity, and examines the impact of IDEAS in Africa

Microsatellite variation between an African and five European taurine breeds results in a geographical phylogenetic tree with a bison outgroup

The genetic relationship between five Belgian breeds (Belgian Blue, Black Pied, Red Pied, White and Red of East Flanders, Red of West Flanders), an African taurine N'Dama breed and a captive American bison herd was studied by means of 31 microsatellite loci. On the basis of the allele frequencies of the 31 scored loci, Nei's modified genetic distance was calculated between the populations. The neighbour joining clustering algorithm was used to construct a possible phylogenetic tree. Herein American bison served as an outgrouThe dendrogram displays a geographical topology with three major lineages as expected, but is unclear in clustering the local breeds

A unified hybrid lattice-Boltzmann method for compressible flows: Bridging between pressure-based and density-based methods

International audienceA unified expression for high-speed compressible segregated consistent lattice Boltzmann methods, namely, pressure-based and improved density-based methods, is given. It is theoretically proved that in the absence of forcing terms, these approaches are strictly identical and can be recast in a unique form. An important result is that the difference with classical density-based methods lies in the addition of fourth-order term in the equilibrium function. It is also shown that forcing terms used to balance numerical errors in both original pressure-based and improved density-based methods can be written in a generalized way. A hybrid segregated efficient lattice-Boltzmann for compressible flow based on this unified model, equipped with a recursive regularization kernel, is proposed and successfully assessed on a wide set of test cases with and without shock waves