1,171 research outputs found
Square vortex solitons with a large angular momentum
We show the existence of square shaped optical vortices with a large value of
the angular momentum hosted in finite size laser beams which propagate in
nonlinear media with a cubic-quintic nonlinearity. The light profiles take the
form of rings with sharp boundaries and variable sizes depending on the power
carried. Our stability analysis shows that these light distributions remain
stable when propagate, probably for unlimited values of the angular momentum,
provided the hosting beam is wide enough. This happens if the peak amplitude
approaches a critical value which only depends on the nonlinear refractive
index of the material. A variational approach allows us to calculate the main
parameters involved. Our results add extra support to the concept of surface
tension of light beams that can be considered as a trace of the existence of a
liquid of light.Comment: 6 pages, 6 figures, submitted to Phys. Rev.
Electron detachment from negative ions in bichromatic laser field
Negative ion detachment in two-colour laser field is considered within the
recent modification of Keldysh model which makes it quantitatively reliable.
The general approach is illustrated by calculation of angular differential
detachment rates, partial rates for particular ATD (Above Threshold Detachment)
channels and total detachment rates for H ion in bichromatic field with 1:2
frequency ratio. Both perturbative and strong field regimes are examined. Polar
asymmetry and phase effects are quantitatively characterized with some new
features revealed. Phase effects are found to result in a huge anisotropy
factor in the electron angular distribution in the perturbative
regime.Comment: 13 pages, 8 figures in separate files which are not incorporated in
the latex file of the pape
90TH ANNIVERSARY OF THE UNION OF PEDIATRICIANS OF RUSSIA
The article is dedicated to the 90th anniversary of the Union of Pediatricians of Russia. Studying the results of academic research, reports, and resolutions of congresses and conferences of Pediatrician Societies, it was observed that discussions organized on pediatric forums which brought up actual problems occurring in pediatrics and clinical practice play an important role in decreasing the rate of child mortality and morbidity, saving millions of child lives in the USSR and modern Russia
Creation, doubling, and splitting, of vortices in intracavity second harmonic generation
We demonstrate generation and frequency doubling of unit charge vortices in a
linear astigmatic resonator. Topological instability of the double charge
harmonic vortices leads to well separated vortex cores that are shown to
rotate, and become anisotropic, as the resonator is tuned across resonance
Solution to the Informatization Problem of Geographical Education in Schools on the Basis of Electronic Cartographical Training Manuals
Розглянуто електронні навчальні картографічні посібники як сучасні моделі представлення знань, сучасні технології розробки та функціональні можливості, проаналізовано новітні технічні досягнення у навчальному процесі. Розкрито основні вимоги до цього виду навчальної картографічної продукції, а також інноваційні педагогічні методи та прийоми, що забезпечують електронні картографічні посібники.
Electronic cartographic
training manuals are considered as modern model of knowledge representation, technology of their design and features is researched, the latest technological advances in the educational process are reviewed. Disclosure of the basic requirements for this type of training cartographic products, as well as new teaching methods and techniques that provide electronic cartographic materials.Роботу виконано на кафедрі геодезії, землевпорядкування і кадастру ВНУ ім. Лесі Українки та кафедрі геодезії і картографії КНУ ім. Т. Шевченк
Evolutionarily new sequences expressed in tumors
BACKGROUND: Earlier we suggested the concept of the positive evolutionary role of tumors. According to this concept, tumors provide conditions for the expression of evolutionarily new and/or sleeping genes in their cells. Thus, tumors are considered as evolutionary proving ground or reservoir of expression. To support this concept we have previously characterized in silico and experimentally a new class of human tumor-related transcribed sequences. RESULTS: In this article we describe results of further studies of previously described tumor-related sequences. The results of molecular phylogeny studies, Southern hybridization experiments and computational comparison with genomes of other species are presented. CONCLUSION: These results suggest that these previously described tumor-related human transcripts are also relatively evolutionarily new
Laser in the axial electric field as a tool to search for P-, T- invariance violation
We consider rotation of polarization plane of the laser light when a gas
laser is placed in a longitudinal electric field (10~kV/cm). It is shown that
residual anisotropy of the laser cavity 10^{-6} and the sensitivity to the
angle of polarization plane rotation about 10^{-11} -10^{-12} rad allows one to
measure an electron EDM with the sensitivity about 10^{-30} e cm.Comment: 12 page
Lithologic-facies and paleogeographic features of Mid-Upper Jurassic oil-gas bearing sediments in Nurolsk depression (Western Siberia)
Bathonian-Callovian-Oxfordian sedimentation environment reconstruction in SE Nurolsk depression, Western Siberia has been described. Paleogeographic and litho-geochemical features of sediments, numerous plant remains and ichnofossils indicated the fact that this territory during the Naunaksk suite formation was the transition in-situ sedimentogenesis. Based on the integrated research data, the potential litho-facies were identified in the Mid-Upper sediments within Nurolsk depression, Western Siberia
- …