Self-adjoint symmetry operators connected with the magnetic Heisenberg ring

We consider symmetry operators a from the group ring C[S_N] which act on the Hilbert space H of the 1D spin-1/2 Heisenberg magnetic ring with N sites. We investigate such symmetry operators a which are self-adjoint (in a sence defined in the paper) and which yield consequently observables of the Heisenberg model. We prove the following results: (i) One can construct a self-adjoint idempotent symmetry operator from every irreducible character of every subgroup of S_N. This leads to a big manifold of observables. In particular every commutation symmetry yields such an idempotent. (ii) The set of all generating idempotents of a minimal right ideal R of C[S_N] contains one and only one idempotent which ist self-adjoint. (iii) Every self-adjoint idempotent e can be decomposed into primitive idempotents e = f_1 + ... + f_k which are also self-adjoint and pairwise orthogonal. We give a computer algorithm for the calculation of such decompositions. Furthermore we present 3 additional algorithms which are helpful for the calculation of self-adjoint operators by means of discrete Fourier transforms of S_N. In our investigations we use computer calculations by means of our Mathematica packages PERMS and HRing.Comment: 13 page

Investigation of inner contact and friction conditions of a spherical roller bearing using multi-body simulation

At the Institute of Machine Elements, Gears, and Transmission (MEGT, University of Kaiserslautern) a spherical roller bearing has been modeled in an multi body system (MBS) environment. The use of the commercial MBS (multi-body system) software (MSC ADAMS) allows the development of user-written subroutines for contact recognition and the calculation of contact forces. Those subroutines can help understanding the principles of friction phenomena inside spherical roller bearings, while the measurement of those effects is difficult.Measurements on a friction torque test rig for roller bearings are used to validate the MBS models. Since the sum of all contact forces equals the friction of the bearing, this test stand provides a way for validation of the contact and friction calculations

«Графічне оформлення схем електричних принципових» методичні вказівки до практичних занять для студентів напрямів підготовки 0501 інформатика та обчислювальна техніка; 0502 автоматика та управління; 0507 електротехніка та електромеханіка; 0509 радіотехніка, радіоелектронні апарати та зв’язок; 0510 метрологія, вимірювальна техніка та інформаційно-вимірювальні технології та 1701 інформаційна безпека.

ЗМІСТ ВСТУП ............................................................................................................................................... 1 1. ЗАГАЛЬНІ ПОНЯТТЯ ПРО СХЕМИ ТА ЇХНЮ КЛАСИФІКАЦІЮ ...................................... 1 2. ВИМОГИ І ПРАВИЛА ВИКОНАННЯ ЕЛЕКТРИЧНИХ ПРИНЦИПОВИХ СХЕМ ............. 1 2.1. ЗАГАЛЬНІ ВИМОГИ ДО ВИКОНАННЯ СХЕМ ................................................................................. 1 2.2. ВИМОГИ ДО ГРАФІЧНОГО ОФОРМЛЕННЯ СХЕМ ......................................................................... 2 2.3. УМОВНІ ГРАФІЧНІ ПОЗНАЧЕННЯ ЕЛЕМЕНТІВ НА ЕЛЕКТРИЧНИХ СХЕМАХ ................................. 4 2.4. ПОЗИЦІЙНІ ЛІТЕРНО-ЦИФРОВІ ПОЗНАЧЕННЯ В ЕЛЕКТРИЧНИХ СХЕМАХ.................................. 12 2.5. ПЕРЕЛІК ЕЛЕМЕНТІВ ................................................................................................................ 16 3. ВКАЗІВКИ ДО ВИКОНАННЯ ЗАВДАННЯ ............................................................................ 18 ЗАПИТАННЯ ДЛЯ САМОКОНТРОЛЮ ...................................................................................... 23 4. ПОРЯДОК ВИКОНАННЯ СХЕМИ ЕЛЕКТРИЧНОЇ ПРИНЦИПОВОЇ В AUTOCAD . ...... 26 ЗАПИТАННЯ ДЛЯ САМОКОНТРОЛЮ ...................................................................................... 31 ЛІТЕРАТУРА .................................................................................................................................. 31Розглянуті загальні вимоги до графічного оформлення схем електричних принципових, систематизовані основні положення державних стандартів зображення і оформлення електричних схем, наведені умовні графічні позначення електричних елементів схем

Serotype- and strain- dependent contribution of the sensor kinase CovS of the CovRS two-component system to Streptococcus pyogenes pathogenesis

<p>Abstract</p> <p>Background</p> <p>The <it>Streptococcus pyogenes </it>(group A streptococci, GAS) two-component signal transduction system CovRS has been described to be important for pathogenesis of this exclusively human bacterial species. If this system acts uniquely in all serotypes is currently unclear. Presence of serotype- or strain-dependent regulatory circuits and polarity is an emerging scheme in <it>Streptococcus pyogenes </it>pathogenesis. Thus, the contribution of the sensor kinase (CovS) of the global regulatory two-component signal transduction system CovRS on pathogenesis of several M serotypes was investigated.</p> <p>Results</p> <p>CovS mutation uniformly repressed capsule expression and hampered keratinocyte adherence in all tested serotypes. However, a serotype- and even strain-dependent contribution on survival in whole human blood and biofilm formation was noted, respectively.</p> <p>Conclusions</p> <p>These data provide new information on the action of the CovS sensor kinase and revealed that its activity on capsule expression and keratinocyte adherence is uniform across serotypes, whereas the influence on biofilm formation and blood survival is serotype or even strain dependent. This adds the CovRS system to a growing list of serotype-specific acting regulatory loci in <it>S. pyogenes</it>.</p

The colonic mucosa-associated microbiome in SIV infection: shift towards Bacteroidetes coincides with mucosal CD4(+) T cell depletion and enterocyte damage

Allers K, Stahl-Hennig C, Fiedler T, et al. The colonic mucosa-associated microbiome in SIV infection: shift towards Bacteroidetes coincides with mucosal CD4(+) T cell depletion and enterocyte damage. SCIENTIFIC REPORTS. 2020;10(1).The intesinal microbiome is considered important in human immunodeficiency virus (HIV) pathogenesis and therefore represents a potential therapeutic target to improve the patients' health status. Longitudinal alterations in the colonic mucosa-associated microbiome during simian immunodeficiency virus (SIV) infection were investigated using a 16S rRNA amplicon approach on the Illumina sequencing platform and bioinformatics analyses. Following SIV infection of six animals, no alterations in microbial composition were observed before the viral load peaked in the colon. At the time of acute mucosal SIV replication, the phylum Bacteroidetes including the Bacteroidia class as well as the phylum Firmicutes and its families Ruminococcaceae and Eubacteriaceae became more abundant. Enrichment of Bacteroidetes was maintained until the chronic phase of SIV infection. The shift towards Bacteroidetes in the mucosa-associated microbiome was associated with the extent of SIV infection-induced mucosal CD4(+) T cell depletion and correlated with increasing rates of enterocyte damage. These observations suggest that Bacteroidetes strains increase during virus-induced mucosal immune destruction. As Bacteroidetes belong to the lipopolysaccharide- and short chain fatty acids-producing bacteria, their rapid enrichment may contribute to inflammatory tissue damage and metabolic alterations in SIV/HIV infection. These aspects should be considered in future studies on therapeutic interventions