Exact quantum master equation for a molecular aggregate coupled to a harmonic bath

We consider a molecular aggregate consisting of $N$ identical monomers. Each monomer comprises two electronic levels and a single harmonic mode. The monomers interact with each other via dipole-dipole forces. The monomer vibrational modes are bilinearly coupled to a bath of harmonic oscillators. This is a prototypical model for the description of coherent exciton transport, from quantum dots to photosynthetic antennae. We derive an exact quantum master equation for such systems. Computationally, the master equation may be useful for the testing of various approximations employed in theories of quantum transport. Physically, it offers a plausible explanation of the origins of long-lived coherent optical responses of molecular aggregates in dissipative environments

Extrapolation of the principles of the quality management for the organization of the system of housing and communal services

В статье рассмотрена возможность применения принципов менеджмента качества в сфере жилищно-коммунального хозяйства. Их внедрение в управляющих компаниях является предпосылкой для разработки системы менеджмента качества, что позволит управляющим компаниям выйти на уровень управления качеством услуг для потребителей, соответствующий международным стандартамIn the article the possibility of application of quality management principles in the sphere of hous-ing and communal services. Their implementation in management companies is a prerequisite for the development of a quality management system that will allow management companies to reach the level of quality management services for consumers that meets international standard

Azimuthal modulation of the event rate of cosmic ray extensive air showers by the geomagnetic field

The Earth's magnetic field effect on the azimuthal distribution of extensive air showers (EAS) of cosmic rays has been evaluated using a bulk of the Yakutsk array data. The uniform azimuthal distribution of the EAS event rate is rejected at the significance level 10^(-14). Amplitude of the first harmonics of observed distribution depends on zenith angle as A1=0.2*sin^2(theta) and is almost independent of the primary energy; the phase coincides with the magnetic meridian. Basing upon the value of measured effect, the correction factor has been derived for the particle density depending on a geomagnetic parameter of a shower.Comment: 4 pages, 3 figures in ps file

Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape

We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064 nm pulsed beams propagate from wider (122 µm) into smaller (37 µm) diameter. In the passive mode, increasing the input beam peak power above 20 kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600 nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length

Dependence of the Energy Spectrum of UHE Cosmic Rays on the Latitude of an Extensive Air Shower Array

Several energy spectra of cosmic rays with energies E_0 \geq 10^17 eV measured at the Yakutsk EAS, AGASA, Haverah Park, HiRes, Auger, and SUGAR arrays are considered. It is shown that the fairly good mutual agreement of the spectrum shapes can be achieved if the energy of each spectrum is multiplied by a factor K specific for each spectrum. These factors exhibit a pronounced dependence on the latitude of the above-mentioned arrays.Comment: 4 pages, 4 figure

The 1986?1989 ENSO cycle in a chemical climate model

International audienceA pronounced ENSO cycle occurred from 1986 to 1989, accompanied by distinct dynamical and chemical anomalies in the global troposphere and stratosphere. Reproducing these effects with current climate models not only provides a model test but also contributes to our still limited understanding of ENSO's effect on stratosphere-troposphere coupling. We performed several sets of ensemble simulations with a chemical climate model (SOCOL) forced with global sea surface temperatures. Results were compared with observations and with large-ensemble simulations performed with an atmospheric general circulation model (MRF9). We focus our analysis on the extratropical stratosphere and its coupling with the troposphere. In this context, the circulation over the North Atlantic sector is particularly important. Observed differences between the El Niño winter 1987 and the La Niña winter 1989 include a negative North Atlantic Oscillation index with corresponding changes in temperature and precipitation patterns, a weak polar vortex, a warm Arctic middle stratosphere, negative and positive total ozone anomalies in the tropics and at middle to high latitudes, respectively, as well as anomalous upward and poleward Eliassen-Palm (EP) flux in the midlatitude lower stratosphere. Most of the tropospheric features are well reproduced in the ensemble means in both models, though the amplitudes are underestimated. In the stratosphere, the SOCOL simulations compare well with observations with respect to zonal wind, temperature, EP flux, and ozone, but magnitudes are underestimated in the middle stratosphere. The polar vortex strength is well reproduced, but within-ensemble variability is too large for obtaining a significant signal in Arctic temperature and ozone. With respect to the mechanisms relating ENSO to stratospheric circulation, the results suggest that both, upward and poleward components of anomalous EP flux are important for obtaining the stratospheric signal and that an increase in strength of the Brewer-Dobson circulation is part of that signal

Stem cells application for the treatment of traumatic brain injury

Traumatic brain injury (TBI) is a global medical and socio-economic problem. Traumatic injuries of the skull and brain make up 30-40 % of all traumas and are the first in terms of mortality and disability among people of working age. High expectations for the treatment of TBI and its consequences are due to the use of stem cell (SCs) therapy. The present review examines the pathogenetic prerequisites for SCs application in TBI effects treatment: generalizes information about the primary and secondary changes in nerve tissue after TBI (cellular, tissue, organ, systemic level) and functional neurological disorders (physical, motor, cognitive, behavioral symptoms); emphasizes the impossibility of restoring neurological functions without restoring brain structures and functions. The paper proposes the main directions of application of SCs for the TBI effects treatment - stimulation of endogenous SCs, transplantation of exogenous SCs and a combination of these approaches. The sources and types of SCs considered for the restoration of the damaged organ and its functional parameters are characterized in detail: embryonic (ESCs), neurogenic (NSC/NPCs), stromal (SCs of bone marrow, adipose tissue, including mesenchymal (MSCs), hematopoietic (HSCs), umbilical cord blood SCs, induced pluripotent SCs (iPSCs). The results of preclinical studies of the different SCs types used in animals with TBI experimental models are summarized. The actual information regarding clinical trials on the safety and efficacy of the SCs application in the TBI effects treatment in the directions of endogenous SCs stimulation (drug administration, physical methods) and exogenous SCs transplantation (autologous SCs (bone marrow, adipose tissue) and allogeneic SCs (MSCs, bone marrow SCs, umbilical cord blood SCs) is analyzed. The gradual accumulation of clinical trial results will allow future meta-analytic studies and the development of certified standardized protocols for the treatment of TBI consequences using the benefits of SCs