Udmurt State University

About: Udmurt State University is a education organization based out in Izhevsk, Russia. It is known for research contribution in the topics: Nonholonomic system & Equations of motion. The organization has 751 authors who have published 1026 publications receiving 6558 citations.

Mitogenetic structure of brown bears (Ursus arctos L.) in northeastern Europe and a new time frame for the formation of European brown bear lineages.

Abstract: We estimated the phylogenetic relationships of brown bear maternal haplotypes from countries of northeastern Europe (Estonia, Finland and European Russia), using sequences of mitochondrial DNA (mtDNA) control region of 231 bears. Twenty-five mtDNA haplotypes were identified. The brown bear population in northeastern Europe can be divided into three haplogroups: one with bears from all three countries, one with bears from Finland and Russia, and the third composed almost exclusively of bears from European Russia. Four haplotypes from Finland and European Russia matched exactly with haplotypes from Slovakia, suggesting the significance of the current territory of Slovakia in ancient demographic processes of brown bears. Based on the results of this study and those from the recent literature, we hypothesize that the West Carpathian Mountains have served either as one of the northernmost refuge areas or as an important movement corridor for brown bears of the Eastern lineage towards northern Europe during or after the last ice age. Bayesian analyses were performed to investigate the temporal framework of brown bear lineages in Europe. The molecular clock was calibrated using Beringian brown bear sequences derived from radiocarbon-dated ancient samples, and the estimated mutation rate was 29.8% (13.3%− − − 47.6%) per million years. The whole European population and Western and Eastern lineages formed about 175 000, 70 000 and 25 000 years before present, respectively. Our approach to estimating the time frame of brown bear evolution demonstrates the importance of using an appropriate mutation rate, and this has implications for other studies of Pleistocene populations.

Local nonequilibrium effect on undercooling in rapid solidification of alloys

Abstract: A local nonequilibrium approach to rapid solidification of undercooled alloys is presented. Taking into account the finite speed of mass signals, a steady-state solution to the nonisothermal rapid solidification problem has been obtained. We have found that, if the solidification front moves at a velocity V equal to or higher than the diffusive speed ${\mathrm{V}}_{\mathrm{D}}^{\mathrm{L}g}$ in the liquid, a partitionless thermal-controlled situation takes place. The solidification mechanism changes at V=${\mathrm{V}}_{\mathrm{D}}^{\mathrm{L}g}$ and the constitutional undercooling is lacking ahead of the solidification front. Some comparisons with the known experimental and theoretical results are discussed.