2,002 research outputs found
CHERNOV-LÜDERS BANDS STUDY IN LOW-CARBON PIPE STEELS
Get PDFВ работе исследованы образцы низкоуглеродистых трубных сталей. Проведена оценка распределения деформаций во время испытаний на растяжение и анализ полос Чернова – Людерса с применением метода цифровой корреляции изображений.The object of the study were the samples of low-carbon pipe steels. The estimation of the strain distribution during the tensile tests and the analysis of Chernov–Lüders bands were done by using the method of digital images correlation
Multilevel ensemble Kalman filtering for spatio-temporal processes
No full textThe ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of the classical Monte Carlo method, which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this talk I will present ideas on combining MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite and infinite dimensional state spaces. Theoretical results and numerical studies of the performance gain of MLEnKF over EnKF will also be presented.
(Joint work with Alexey Chernov, Kody J. H. Law, Fabio Nobile, and Raul Tempone.)
References:
[1] H. Hoel, K. Law, and R. lTempone(2016). Multilevelensemble Kalman filtering. SIAM J. Numer. Anal. 54(3), 1813–1839.
[2] A. Chernov, H. Hoel, K. Law, F. Nobile, and R. Tempone (2016). Multilevel ensemble Kalman filtering for spatially extended models. ArXiv e-prints. arXiv: 1608.08558 [math.NA].KAUST CRG4 Award Ref:2584
Role of deep brain stimulation in management of psychiatric disorders
No full textNowadays, most of patients affected by psychiatric disorders are successfully treated with con-
servative therapies. Still, a variable percentage of them demonstrate resistance to conventional
treatments, and alternative methods can then be considered. During the last 20 years, there is a
progressive interest in use of deep brain stimulation (DBS) in mental illnesses. It has become
clear nowadays, that this modality may be effectively applied under specific indications in
some patients with major depressive disorder, obsessive-compulsive disorder, anorexia ner-
vosa and other eating disorders, Tourette syndrome, schizophrenia, substance use disorder,
and even pathologically aggressive behavior. Despite the fact that the efficacy of neuromodu-
lation with DBS, as well as of various lesional interventions, in cases of mental illnesses is still
not fully established, there are several premises for wider applications of such “unclassical”
psychiatric treatments in the future. Novel technologies of DBS, developments in non-invasive
lesioning using stereotactic radiosurgery and transcranial magnetic resonance–guided focused
ultrasound, and advances of neurophysiological and neuroimaging modalities may bolster fur-
ther clinical applications of psychiatric neurosurgery, improve its results, and allow for indi-
vidually selected treatment strategies tailored to specific needs of the patient
Support for the Socialist Revolutionary Party during 1917, with a case study of events in Nizhegorodskaia guberniia.
Get PDFResearch data supporting "Surface plasmons on Pd(110): An ab initio calculation"
No full textWe provide supporting dataset corresponding to the paper “Surface plasmon on Pd(110): an ab initio calculation”, by U. Muniain, R. Esteban, I. P. Chernov, J. Aizpurua and V. M. Silkin, published in Physical Review B (DOI: 10.1103/PhysRevB.103.045407). The dataset is organized in 12 binary files to extract the imaginary part of the noninteracting response function Xi0_{GG’}(q,w) (as determined by Eq. (3) in the article), for three particular q vectors in the Gamma-X direction: q = 0.0168 1/Å, q = 0.0840 1/Å and q = 0.4032 1/Å. For q = 0.0168 1/Å, the full set of data is divided into four files “Pd110_01_Ax”, where x = 1, 2, 3 and 4. We also include a FORTRAN program “Reading_Xi0_IM_01.f” that reads the response function from those four files for a range of energies, as determined in the FORTRAN program. This FORTRAN program can be used to handle the data, as stated in the program itself. For the other two q vectors, the data (four files) and the reading FORTRAN program are organized in the same way, where the number “01” in the files of the example above is replaced by “05” for q = 0.0840 1/Å and by “24” for q = 0.4032 1/Å.Peer reviewe
Assemblages of herb-dwelling spiders (Araneae) of various steppe types in Ukraine and the Central Chernozem region of Russia
No full textA total of 107 spider species from 15 families were recorded in the herbaceous vegetation of the steppe ecosystems of Ukraine and the Central Chernozem region of Russia. Araneidae, Thomisidae, Salticidae and Theridiidae were the most species-rich. The species composition depended on the steppe type; adjacent forest habitats influenced steppe fauna in the forest-steppe and northern part of the steppe natural zone. The number of generalist, forest and wetland dwelling species in the steppe vegetation showed a tendency to decrease towards the south. Dominance of herb-dwelling spiders was specific to each steppe type; no single species was found to predominate in all the steppe habitats
Polymorphisms of drug-metabolizing enzymes CYP2C9, CYP2C19, CYP2D6, CYP1A1, NAT2 and of P-glycoprotein in a Russian population
No full textObjective. The frequency of functionally important mutations and alleles of genes coding for xenobiotic metabolizing enzymes shows a wide ethnic variation. However, little is known of the frequency distribution of the major allelic variants in the Russian population. Methods. Using polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) genotyping assays and the real-time PCR with fluorescent probes, the frequencies of functionally important variants of the cytochromes P-450 (CYP) 2C9, 2C19, 2D6, 1A1 as well as arylamine N-acetyltransferase 2 (NAT2) and P-glycoprotein (MDR1) were determined in a sample of 290 Russian volunteers derived from Voronezh area. Results. CYP2C9 2 and 3 alleles were found with allelic frequencies of 10.5% and 6.7%, respectively. The novel intron-2 T>C mutation at exon 2 +73 bp occurred in 24.8% of alleles. CYP2C19 2 and 3 alleles occurred in 11.4% and 0.3%, respectively. Six persons (2.1%) carried two of these CYP2C19 alleles responsible for poor metabolizing activity. Of all subjects, 5.9% were CYP2D6 poor metabolizers, whereas 3.4% were addressed to ultra-rapid metabolizers (CYP2D6 1x2/ 1). The CYP1A1 2A allele was found in 4.7%, 2B in 5.0%, 4 in 2.6%, and the 5'-mutations -3219C>T, -3229G>A, and the novel -4335G>A in 6.0%, 2.9% and 26.0% of alleles, respectively. Genotyping of eight different single nucleotide polymorphisms in the NAT2 gene provided in 58.0% a genotype associated with slow acetylation. The MDR1 triple variants G2677T and G2677A in exon 21 had an allelic frequency of 41.9% and 3.3%, respectively, and the variant C3435T in exon 26 one of 54.3%. Frequencies of functionally important haplotypes were calculated. Conclusion. The overview of allele distribution of important xenobiotic-metabolizing enzymes among a Russian population shows similarity to other Caucasians. The data will be useful for clinical pharmacokinetic investigations and for drug dosage recommendations in the Russian population
Pod systems : an equivariant ordinary differential equation approach to dynamical systems on a spatial domain
Get PDFWe present a class of systems of ordinary differential equations (ODEs), which we call 'pod systems', that offers a new perspective on dynamical systems defined on a spatial domain. Such systems are typically studied as partial differential equations, but pod systems bring the analytic techniques of ODE theory to bear on the problems, and are thus able to study behaviours and bifurcations that are not easily accessible to the standard methods. In particular, pod systems are specifically designed to study spatial dynamical systems that exhibit multi-modal solutions.
A pod system is essentially a linear combination of parametrized functions in which the coefficients and parameters are variables whose dynamics are specified by a system of ODEs. That is, pod systems are concerned with the dynamics of functions of the form psi(s, t) = y(1)(t)phi(s; x(1)(t)) + ... + y(N)(t)phi(s; x(N)(t)), where s is an element of R-n is the spatial variable and phi: R-n x R-d -> R. The parameters x(i) is an element of R-d and coefficients y(i) is an element of R are dynamic variables which evolve according to some system of ODEs,. x(i) = G(i)(x, y) and y(i) = H-i(x, y), for i = 1,..., N. The dynamics of psi in function space can then be studied through the dynamics of the x and y in finite dimensions.
A vital feature of pod systems is that the ODEs that specify the dynamics of the x and y variables are not arbitrary; restrictions on G(i) and H-i are required to guarantee that the dynamics of psi in function space are well defined (that is, that trajectories are unique). One important restriction is symmetry in the ODEs which arises because psi is invariant under permutations of the indices of the (x(i), y(i)) pairs. However, this is not the whole story, and the primary goal of this paper is to determine the necessary structure of the ODEs explicitly to guarantee that the dynamics of psi are well defined
Competitiveness of the enterprise on the market when developing new production
Get PDFThe purposes of the study are to analyse competitiveness and develop recommendations for improving it when mastering production of new products. When reviewing well-known works where competitiveness has been studied, the author has examined the impact of changes at the macro level on the processes of developing new products by enterprises. In the article, the author has analysed various approaches to determining competitiveness. The influence of unilateral sanctions on competitiveness in the development of new products has been considered. At the same time, it is noted that sanctions as a tool of forceful pressure cannot be used as a tool for increasing success of enterprises in a fair competitive market. Therefore, the author highlights that the classical theory of competitive and non-competitive markets is not fully applicable in the current situation. In the works of some scientists, the competitiveness of an enterprise in the market that does not correspond to present realities has been analysed, and accordingly, such studies are not applicable in the conditions of a necessary fair competitive market. The author has suggested ways to determine both current competitiveness and its indicators in past and future periods. It is proposed to restructure the domestic technology transfer to the international one with friendly countries, moving from simple trade and exchange of goods to joint product development. Conditions are also needed within the country for scaling ideas and new designs. In an uncompetitive market, merging or associating companies for research, development and mastery the production of new products may be one of the ways to circumvent sanctions. Thus, the method is more applicable to technologies with a high level of digital and technological protection in the know-how mode
Cauchy surfaces and diffeomorphism types of globally hyperbolic spacetimes
No full textChernov–Nemirovski observed that the existence of a globally hyperbolic Lorentzian metric on a -spacetime pins down a smooth structure on the underlying four-manifold. In this paper, we point out that the diffeomorphism type of a globally hyperbolic -spacetime is determined by the h-cobordism class of its Cauchy surface, hence extending Chernov–Nemirovskiʼs observation to arbitrary dimensions. © 2014 IOP Publishing Ltd
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