A solution to the problems of cusps and rotation curves in dark matter halos in the cosmological standard model

We discuss various aspects of the inner structure formation in virialized dark matter (DM) halos that form as primordial density inhomogeneities evolve in the cosmological standard model. The main focus is on the study of central cusps/cores and of the profiles of DM halo rotation curves, problems that reveal disagreements among the theory, numerical simulations, and observations. A method that was developed by the authors to describe equilibrium DM systems is presented, which allows investigating these complex nonlinear structures analytically and relating density distribution profiles within a halo both to the parameters of the initial small-scale inhomogeneity field and to the nonlinear relaxation characteristics of gravitationally compressed matter. It is shown that cosmological random motions of matter `heat up' the DM particles in collapsing halos, suppressing cusp-like density profiles within developing halos, facilitating the formation of DM cores in galaxies, and providing an explanation for the difference between observed and simulated galactic rotation curves. The analytic conclusions obtained within this approach can be confirmed by the N-body model simulation once improved spatial resolution is achieved for central halo regions.Comment: 44 pages, 16 figures, 1 tabl

Current-induced highly dissipative domains in high Tc thin films

We have investigated the resistive response of high Tc thin films submitted to a high density of current. For this purpose, current pulses were applied into bridges made of Nd(1.15)Ba(1.85)Cu3O7 and Bi2Sr2CaCu2O8. By recording the time dependent voltage, we observe that at a certain critical current j*, a highly dissipative domain develops somewhere along the bridge. The successive formation of these domains produces stepped I-V characteristics. We present evidences that these domains are not regions with a temperature above Tc, as for hot spots. In fact this phenomenon appears to be analog to the nucleation of phase-slip centers observed in conventional superconductors near Tc, but here in contrast they appear in a wide temperature range. Under some conditions, these domains will propagate and destroy the superconductivity within the whole sample. We have measured the temperature dependence of j* and found a similar behavior in the two investigated compounds. This temperature dependence is just the one expected for the depairing current, but the amplitude is about 100 times smaller.Comment: 9 pages, 9 figures, Revtex, to appear in Phys. Rev.

Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere

Mitral insufficiency: systematization, conservative and surgical treatment

The article concerns mechanisms, clinical features, diagnostics, possible complications and treatment of mitral insufficiency. Much attention is given to modern diagnostic methods, principles for case management and indications for surgical treatment

On the theory of Lamb wave excitation in metals by pulsed laser radiation

The problem of pulsed photoacoustic transformation is solved for ferromagnetic metal plates. The effect of the temperature dependence of the thermal coefficient of linear expansion on the spectrum of Lamb waves excited by pulsed laser is revealed. © 2011 Pleiades Publishing, Ltd

Experimental determination of parameters of laser-generated Lamb waves

The process of laser generation of Lamb wave pulses in a ferromagnet by the evaporation mechanism has been studied experimentally. The results can be recommended for developing methods and tools for testing thin-wall metal items. © Pleiades Publishing, Ltd., 2010

Studying the temperature dependences of the parameters of laser-generated lamb waves

The process of laser generation of pulses of symmetrical and antisymmetrical Lamb waves in a ferromagnetic plate due to the thermoelastic effect was experimentally studied. The temperature dependences of the shape, amplitude, duration, and vibration frequency of acoustic pulses and the velocities of their propagation in the plate were investigated. © 2011 Pleiades Publishing, Ltd

Influence of the properties of a ferromagnetic metal on the spectrum of Rayleigh waves excited by pulsed laser radiation

A solution to the problem of laser generation of Rayleigh wave pulses in ferromagnetic metals is theoretically studied. The spectra of acoustic pulses are determined in the thermoelastic approximation taking into account a finite value of the heat-flux relaxation time, the metal absorption coefficient, and a change in the thermal linear expansion coefficient. An estimate is obtained for the maximum excess temperature in a half-space upon absorption of an optical pulse. © Pleiades Publishing, Ltd., 2010