On the reliability of linear band structure methods

We discuss an efficiency of various band structure algorithms in determining the Fermi surface (FS) of the paramagnetic ErGa3. The linear muffin-tin orbital (LMTO) in the atomic sphere approximation (ASA) method and three full potential (FP) codes: FP-LMTO, FP linear augmented plane wave (FLAPW), and FP local orbitals (FPLO) methods are employed. Results are compared with electron-positron (e-p) momentum densities reconstructed from two dimensional angular correlation of annihilation radiation (2D ACAR). Unexpectedly, none of used modern FP codes is able to give satisfying description of the experimental data that are in perfect agreement with LMTO-ASA results. We suspect that it can be connected with a different choice of the linearization energy.Comment: 6 pages, 2 figure

Advanced Training of CNC Machine Operators as a Factor of Production Modernization

В представленной статье изучается вопрос о нехватке квалифицированных кадров на производстве, в условиях модернизации оборудования.This article examines the issue of the shortage of qualifi ed personnel in production, in the conditions of modernization of equipment

«Having lost his homeland, he gained recognition in a foreign land...». Life and fate of the russian military engineer Vladimir Apollonovich Antonov

Introduction. The article examines the trajectory of the life of a representative of the officer corps of the Russian Imperial Army, military engineer Vladimir Apollonovich Antonov. This choice is explained by the fact that recently the issues of studying the biographies of representatives of Russian emigration have become very relevant.Materials and methods. The authors of the article conducted a microhistoric study of the fate of one of these representatives, which demonstrated both typical and special episodes from his life. The basis of the work was the data of Address calendars and Commemorative books of the Vyatka and Tambov provinces, materials of the State Archive of the Tambov region and the Russian State Military Historical Archive.Results. As a result of studying various sources, it was possible to compile a description of our hero's youthful years during his studies in Tambov. Consider the nuances associated with obtaining a military education, starting service, acquiring the first combat experience and completing training at the military academy. Having studied the documents of the period of the First World War, the authors were able to trace the combat path of Vladimir Apollonovich, who was awarded several awards. During the "troubled" period of the Civil War, it was possible to find out the fact of his participation in the ranks of the white movement and emigration. The apotheosis of the research was the fate of V.A. Antonov abroad, where he was able to realize his vocation and enter the history of the city of Kumanovo. In addition, the result of the work was the clarification of some inaccuracies and errors made earlier in the works of some researchers.Conclusion. Conducting such studies allows us to give an objective assessment of the multifaceted fate of the Russian military emigration, which represented an impressive layer of our compatriots who found themselves in the Kingdom of Serbs, Croats and Slovenes

Pressure effect on the Fermi surface and electronic structure of LuGa₃ and TmGa₃

The Fermi surfaces and cyclotron masses of LuGa₃ and TmGa₃ compounds are studied by means of the de Haas—van Alphen effect technique under pressure. The highly anisotropic pressure dependences of the de Haas—van Alphen frequencies and cyclotron masses have been observed in both compounds. Concurrently, the ab initio calculations of the volume-dependent band structures have been carried out for these compounds, including ferromagnetic configuration phase of TmGa₃, by employing a relativistic version of the full-potential linear muffin-tin orbital method within the local spin-density approximation. The experimental data have been analysed on the basis of the calculated volume-dependent band structures and compared with the corresponding pressure effects in the isostructural compound ErGa₃

Gene-history correlation and population structure

Correlation of gene histories in the human genome determines the patterns of genetic variation (haplotype structure) and is crucial to understanding genetic factors in common diseases. We derive closed analytical expressions for the correlation of gene histories in established demographic models for genetic evolution and show how to extend the analysis to more realistic (but more complicated) models of demographic structure. We identify two contributions to the correlation of gene histories in divergent populations: linkage disequilibrium, and differences in the demographic history of individuals in the sample. These two factors contribute to correlations at different length scales: the former at small, and the latter at large scales. We show that recent mixing events in divergent populations limit the range of correlations and compare our findings to empirical results on the correlation of gene histories in the human genome.Comment: Revised and extended version: 26 pages, 5 figures, 1 tabl

Familial twinning and fertility in Dutch mothers of twins.

We studied twinning and fertility indices in mothers with spontaneous monozygotic (MZ) and dizygotic (DZ) twins and in mothers who conceived their twins after the use of assisted reproduction techniques (ART). Participants in this study consisted of 8,222 and 5,505 women with spontaneous DZ and MZ offspring and 4,164 and 250 women with ART DZ and MZ twin pairs, respectively. Women were compared with respect to the number of sibs and offspring, the presence of other relatives with twins and the time it took to conceive the twins. We also compared familial twinning between a younger and an older age group. Women with spontaneous DZ twins more often reported female relatives with twins than those with spontaneous MZ twins. The proportion of DZ versus MZ twin offspring in relatives was also larger in women with spontaneous DZ offspring than in women with MZ offspring. The first group of women reported a shorter time to conceive. Women with ART twins had fewer sibs and offspring and less often reported relatives with twins. We did not observe that DZ twinning was more familial in women who had their twins before age 36 years compared to older women. Familial DZ twinning is clearly present in mothers of spontaneous DZ twins. The mechanisms underlying spontaneous and non-spontaneous DZ twinning are different and fertility treatment should be taken into account in any study of twinning. Twinning is not more familial in women who have their twins at a younger age

Genome-wide association and meta-analysis in populations from Starr County, Texas, and Mexico City identify type 2 diabetes susceptibility loci and enrichment for expression quantitative trait loci in top signals

AIMS/HYPOTHESIS: We conducted genome-wide association studies (GWASs) and expression quantitative trait loci (eQTL) analyses to identify and characterise risk loci for type 2 diabetes in Mexican-Americans from Starr County, TX, USA. METHOD: Using 1.8 million directly interrogated and imputed genotypes in 837 unrelated type 2 diabetes cases and 436 normoglycaemic controls, we conducted Armitage trend tests. To improve power in this population with high disease rates, we also performed ordinal regression including an intermediate class with impaired fasting glucose and/or glucose tolerance. These analyses were followed by meta-analysis with a study of 967 type 2 diabetes cases and 343 normoglycaemic controls from Mexico City, Mexico. RESULT: The top signals (unadjusted p value <1×10(−5)) included 49 single nucleotide polymorphisms (SNPs) in eight gene regions (PER3, PARD3B, EPHA4, TOMM7, PTPRD, HNT [also known as RREB1], LOC729993 and IL34) and six intergenic regions. Among these was a missense polymorphism (rs10462020; Gly639Val) in the clock gene PER3, a system recently implicated in diabetes. We also report a second signal (minimum p value 1.52× 10(−6)) within PTPRD, independent of the previously implicated SNP, in a population of Han Chinese. Top meta-analysis signals included known regions HNF1A and KCNQ1. Annotation of top association signals in both studies revealed a marked excess of trans-acting eQTL in both adipose and muscle tissues. CONCLUSIONS/INTERPRETATION: In the largest study of type 2 diabetes in Mexican populations to date, we identified modest associations of novel and previously reported SNPs. In addition, in our top signals we report significant excess of SNPs that predict transcript levels in muscle and adipose tissues

Population History and Natural Selection Shape Patterns of Genetic Variation in 132 Genes

Identifying regions of the human genome that have been targets of natural selection will provide important insights into human evolutionary history and may facilitate the identification of complex disease genes. Although the signature that natural selection imparts on DNA sequence variation is difficult to disentangle from the effects of neutral processes such as population demographic history, selective and demographic forces can be distinguished by analyzing multiple loci dispersed throughout the genome. We studied the molecular evolution of 132 genes by comprehensively resequencing them in 24 African-Americans and 23 European-Americans. We developed a rigorous computational approach for taking into account multiple hypothesis tests and demographic history and found that while many apparent selective events can instead be explained by demography, there is also strong evidence for positive or balancing selection at eight genes in the European-American population, but none in the African-American population. Our results suggest that the migration of modern humans out of Africa into new environments was accompanied by genetic adaptations to emergent selective forces. In addition, a region containing four contiguous genes on Chromosome 7 showed striking evidence of a recent selective sweep in European-Americans. More generally, our results have important implications for mapping genes underlying complex human diseases