Unimodular metagravity vs. General Relativity with a scalar field

The unimodular metagravity, with the graviscalar as a dark matter, is compared with General Relativity (GR) in the presence of a scalar field. The effect of the graviscalar on the static spherically symmetric metric is studied. An exact limit solution representing a new cosmic object, the (harmonic) graviscalar black hole, is given. The relation with the black hole in the environment of a scalar field in GR is discussed.Comment: 7 pages. Report presented at the RAS Conference "Physics of Fundamental Interactions", Protvino, December 22-25, 200

Markov Process of Muscle Motors

We study a Markov random process describing a muscle molecular motor behavior. Every motor is either bound up with a thin filament or unbound. In the bound state the motor creates a force proportional to its displacement from the neutral position. In both states the motor spend an exponential time depending on the state. The thin filament moves at its velocity proportional to average of all displacements of all motors. We assume that the time which a motor stays at the bound state does not depend on its displacement. Then one can find an exact solution of a non-linear equation appearing in the limit of infinite number of the motors.Comment: 10 page

A Search for Small-Scale Clumpiness in Dense Cores of Molecular Clouds

We have analyzed HCN(1-0) and CS(2-1) line profiles obtained with high signal-to-noise ratios toward distinct positions in three selected objects in order to search for small-scale structure in molecular cloud cores associated with regions of high-mass star formation. In some cases, ripples were detected in the line profiles, which could be due to the presence of a large number of unresolved small clumps in the telescope beam. The number of clumps for regions with linear scales of ~0.2-0.5 pc is determined using an analytical model and detailed calculations for a clumpy cloud model; this number varies in the range: ~2 10^4-3 10^5, depending on the source. The clump densities range from ~3 10^5-10^6 cm^{-3}, and the sizes and volume filling factors of the clumps are ~(1-3) 10^{-3} pc and ~0.03-0.12. The clumps are surrounded by inter-clump gas with densities not lower than ~(2-7) 10^4 cm^{-3}. The internal thermal energy of the gas in the model clumps is much higher than their gravitational energy. Their mean lifetimes can depend on the inter-clump collisional rates, and vary in the range ~10^4-10^5 yr. These structures are probably connected with density fluctuations due to turbulence in high-mass star-forming regions.Comment: 23 pages including 4 figures and 4 table

A new approach to the relativistic treatment of the fermion-boson system, based on the extension of the SL(2,C) group

A new technique for constructing the relativistic wave equation for the two-body system composed of the spin-1/2 and spin-0 particles is proposed. The method is based on the extension of the SL(2,C) group to the Sp(4,C) one. The obtained equation includes the interaction potentials, having both the Lorentz-vector and Lorentz-tensor structure, exactly describes the relativistic kinematics and possesses the correct one-particle limits. The comparison with results of other approaches to this problem is discussed.Comment: v3: revised version (to appear in Mod. Phys. Lett. A

Sodium-23 Magnetic Resonance Imaging

23Na MRI provides additional biochemical information to 1H MRI in terms of cell integrity and tissue viability. We aimed at determining the sensitivity of 23Na MRS, MRI and MR relaxometry methods available on 7T MR scanner Bruker Biospec 70/30 USR and developing of an optimal MRI protocol for small animal 23Na in vivo visualization. The outcomes include 23Na MR spectra, 23Na MR images with SNRs, and T1 and T2 values of 23Na. It is shown that single-pulse 23Na MR spectroscopy can discriminate different 23Na concentrations, and 3D FLASH pulse sequence adapted for 23Na data acquisition may provide the acceptable quality images. Keywords: Sodium MRI, Sodium MRS, 3D FLASH, MR relaxometr

Magnetism of ordered and disordered alloys of R2Fe14B (R = Nd, Er) type

Magnetic susceptibility, magnetization and neutron diffraction measurements have been performed to study structure and magnetic states of crystalline and amorphous Nd2Fe14B and Er2Fe14B alloys. In the crystalline state there exists a large (about 20%) anisotropy of Er-sublattice magnetization. Values of the magnetic anisotropy constant of Er ions and the Er-Fe exchange-coupling parameter were estimated using temperature dependence of the Er-and Fe-sublattice magnetizations. Amorphous state of the samples was obtained by irradiation of fast (Eeff≥1MeV) neutrons with a fluence up to the 1.2 Ч 1020 n/cm-2 at 340 K. It is shown that antiferromagnetic coupling between the rare-earth and iron spins is kept in the amorphous state. Amorphization of the samples is found to result in reduction of the Curie temperature (TC) by about 200 K and almost total absence of coercivity. We suggest that the strong decrease of TC is a consequence of enhancement of negative Fe-Fe interactions as a result of dispersion of interatomic distances, which is a characteristic feature of the amorphous state. © 2013 Elsevier B.V. All rights reserved

Lorentz gauge theory as a model of emergent gravity

We consider a class of Lorentz gauge gravity theories within Riemann-Cartan geometry which admits a topological phase in the gravitational sector. The dynamic content of such theories is determined only by the contortion part of the Lorentz gauge connection. We demonstrate that there is a unique Lagrangian that admits propagating spin one mode in correspondence with gauge theories of other fundamental interactions. Remarkably, despite the R^2 type of the Lagrangian and non-compact structure of the Lorentz gauge group, the model possesses rather a positive-definite Hamiltonian. This has been proved in the lowest order of perturbation theory. This implies further consistent quantization and leads to renormalizable quantum theory. It is assumed that the proposed model describes possible mechanism of emergent Einstein gravity at very early stages of the Universe due to quantum dynamics of contortion.Comment: 11 pages, final version, minor correction

Unimodular bimode gravity and the coherent scalar-graviton field as galaxy dark matter

The explicit violation of the general gauge invariance/relativity is adopted as the origin of dark matter and dark energy of the gravitational nature. The violation of the local scale invariance alone, with the residual unimodular one, is considered. Besides the four-volume preserving deformation mode -- the transverse-tensor graviton -- the metric comprises a compression mode -- the scalar graviton, or the systolon. A unimodular invariant and general covariant metric theory of the bimode/scalar-tensor gravity is consistently worked out. To reduce the primordial ambiguity of the theory a dynamical global symmetry is imposed, with its subsequent spontaneous breaking revealed. The static spherically symmetric case in the empty, but possibly for the origin, space is studied. A three-parameter solution describing a new static space structure -- the dark lacuna -- is constructed. It enjoys the property of gravitational confinement, with the logarithmic potential of gravitational attraction at the periphery, and results in the asymptotically flat rotation curves. Comprising a super-massive dark fracture (a scalar-modified black hole) at the origin surrounded by a cored dark halo, the dark lacunas are proposed as a prototype model of galaxies, implying an ultimate account for the distributed non-gravitational matter and a putative asphericity or rotation.Comment: 38 pages, 10 figures; exposition improved, remarks added, accepted for publicatio

Macrophage phenotype after human refluxate exposure, esophageal dysmotility and their correlation with gastroesophageal reflux disease

Aim of the study. To investigate the esophageal dysmotility, changes in the esophageal mucosa and the immune response depending on the type of refluxate in gastroesophageal reflux disease (GERD) patients.Material and methods. 68 patients with GERD were recruited: 28 (14 men; mean age, 45.74 ± 2.23 years) nonerosive reflux disease (NERD), 22 (15 men; mean age, 45.0 ± 3.24 years) erosive reflux disease (EE), 18 (13 men; mean age, 47.22 ± 2.95) Barrett’s Esophagus (BE). GERD patients underwent esophageal high-resolution manometry (HRM) with a 22-channel water-perfused catheter and Solar GI system (Medical Measurements Systems, Enschede, the Netherlands), 24-hour impedance and pH monitoring using the Ohmega Ambulatory Impedance pH Recorder (Medical Measurements Systems). We analyzed receptor characteristics of monocyte-derived macrophages in all groups of patients.Results. On HRM examination, we showed that DCI (distal contractile integral) in NERD patients was higher than in EE (p = 0.088) and BE (p = 0.076), also LES RP (lower esophageal sphincter resting pressure) in NERD patients was higher than in EE (p = 0.039) and BE (p = 0.012). The analysis of reflux characteristics showed that the total reflux time with pH < 4 for BE patients was longer than that for NERD and EE patients. An analysis of receptor characteristics of monocyte-derived macrophages showed the prevalence of CD25 and CD80 expression in all groups of patients.Conclusion. An analysis of the phenotype of macrophages derived from blood monocytes of GERD patients revealed a prevalence of М1 macrophages that was typical for the Th1 type of immune response. The degree of esophageal dysmotility was correlated with GERD severity and type