The connected components of the space of Alexandrov surfaces

Denote by $\mathcal{A}(\kappa)$ the set of all compact Alexandrov surfaces with curvature bounded below by $\kappa$ without boundary, endowed with the topology induced by the Gromov-Hausdorff metric. We determine the connected components of $\mathcal{A}(\kappa)$ and of its closure

Simulations of magnetic and magnetoelastic properties of Tb2Ti2O7 in paramagnetic phase

Magnetic and magnetoelastic properties of terbium titanate pyrochlore in paramagnetic phase are simulated. The magnetic field and temperature dependences of magnetization and forced magnetostriction in Tb2Ti2O7 single crystals and polycrystalline samples are calculated in the framework of exchange charge model of crystal field theory and a mean field approximation. The set of electron-deformation coupling constants has been determined. Variations of elastic constants with temperature and applied magnetic field are discussed. Additional strong softening of the crystal lattice at liquid helium temperatures in the magnetic field directed along the rhombic symmetry axis is predicted.Comment: 13 pages, 4 figures, 2 table

Nucleon polarizabilities in the perturbative chiral quark model

The nucleon polarizabilities alpha(E) and beta(M) are studied in the context of the perturbative chiral quark model. We demonstrate that meson cloud effects are sufficient to explain the electric polarizability of nucleon. Contributions of excite quark states to the paramagnetic polarizability are dominant and cancel the diamagnetic polarizability arising from the chiral field. The obtained results are compared to data and other theoretical predictions.Comment: 25 pages, 18 figures, 2 table

Scaling law of the plasma turbulence with non conservative fluxes

It is shown that in the presence of anisotropic kinetic dissipation existence of scale invariant power law spectrum of plasma turbulence is possible. Obtained scale invariant spectrum is not associated with the constant flux of any physical quantity. Application of the model to the high frequency part of the solar wind turbulence is discussed.Comment: Phys Rev E, accepte

Optical measurements of spin noise as a high resolution spectroscopic tool

The intrinsic fluctuations of electron spins in semiconductors and atomic vapors generate a small, randomly-varying "spin noise" that can be detected by sensitive optical methods such as Faraday rotation. Recent studies have demonstrated that the frequency, linewidth, and lineshape of this spin noise directly reveals dynamical spin properties such as dephasing times, relaxation mechanisms and g-factors without perturbing the spins away from equilibrium. Here we demonstrate that spin noise measurements using wavelength-tunable probe light forms the basis of a powerful and novel spectroscopic tool to provide unique information that is fundamentally inaccessible via conventional linear optics. In particular, the wavelength dependence of the detected spin noise power can reveal homogeneous linewidths buried within inhomogeneously-broadened optical spectra, and can resolve overlapping optical transitions belonging to different spin systems. These new possibilities are explored both theoretically and via experiments on spin systems in opposite limits of inhomogeneous broadening (alkali atom vapors and semiconductor quantum dots).Comment: 4 pages, 4 figure

A Low-Noise High-Density Alkali Metal Scalar Magnetometer

We present an experimental and theoretical study of a scalar atomic magnetometer using an oscillating field-driven Zeeman resonance in a high-density optically-pumped potassium vapor. We describe an experimental implementation of an atomic gradiometer with a noise level below 10 fT/Hz^{1/2}, fractional field sensitivity below 10^{-9}/Hz^{1/2}, and an active measurement volume of about 1.5 cm^3. We show that the fundamental field sensitivity of a scalar magnetometer is determined by the rate of alkali-metal spin-exchange collisions even though the resonance linewidth can be made much smaller than the spin-exchange rate by pumping most atoms into a stretched spin state.Comment: 10 pages, 7 figures. Version 2 is longer, with more complete description of theoretical analysis and comparison between analytical and experimental result

Вплив харчової добавки "магнетофуд" на структурно-механічні властивості формового желейного мармеладу з різними структуроутворювачами

Development of resource- and energy-saving technologies for the production of high-quality jelly and pastille products with an extended shelf life is one of the most urgent challenges of the modern confectionery industry. It is proposed to use the "Magnetofood" mineral food supplement, which holds a high functional and technological potential and may independently form the structural and mechanical properties of jelly pastes, and also affect the gelling agents, entering into chemical and electrostatic interactions therewith. Therefore, the "Magnetofood" food supplement may influence several technological properties in the food jelly system at once: acting as a stabilizer, a thickener, a gelling agent, while improving the quality, consumer properties and extending the shelf life of molded fruit jelly products. The aim of the study is to improve the structural and mechanical properties of molded fruit jelly products by introducing the "Magnetofood" food supplement. Standard and generally accepted methods were used in the course of structural and mechanical studies (viscosity and thixotropic characteristics on the Reotest-2 rotation viscometer, strength characteristics on the AR-4/1 penetrometers). It has been established that the introduction of the "Magnetofood" food supplement into jelly pastes in the amount of 0.15 % of the total weight of raw material improves the consistency, structure, strength and form: the degree of structuring and viscosity of the jelly pastes increases over the entire shear stress range (1.5-40 s⁻¹) 2.9 times for pastes on agar and 1.85 times for pastes on pectin; the temperature effect on the effective viscosity of jelly pastes is slowed down by (50-75) Pa · s on average, destruction processes are also slowed down 1.1 times, and the recovery processes of the jelly structure after the mechanical effect ceases are accelerated by 3.8%, increasing its thixotropic ability by 7.5% in jelly pastes on agar and by 6.0% in jelly pastes on pectin; jelly strength on agar increases by (10-12)%, and by (7-9) % on pectin; the speed of structurization of jelly pastes on agar increases by a factor of 1.3-1.7, and by a factor of 1.1-1.6 on pectin.Однією з актуальних проблем сучасної кондитерської промисловості є розробка ресурсо- і енергозберігаючих технологій виробництва високоякісних мармеладо-пастильних виробів зі збільшеним терміном придатності. Пропонується використання мінеральної харчової добавки "Магнетофуд", яка володіє високим функціонально-технологічним потенціалом і може як самостійно формувати структурно-механічні властивості желейних мас, так і впливати на гелеутворювач, вступаючи з ним в хімічні і електростатичні взаємодії. Тому, харчова добавка "Магнетофуд" може впливати відразу на кілька технологічних властивостей в харчовій желейної системі: бути стабілізатором, загусником, драглеутворювачем, при цьому покращуючи якість, споживчі властивості і продовжуючи терміни зберігання формового желейного мармеладу. Метою дослідження є покращення структурно-механічних властивостей формового желейного мармеладу шляхом введення харчової добавки "Магнетофуд". Під час проведення структурно-механічних (в’язкостних і тиксотропних характеристик на ротаційному віскозиметрі Реотест-2, міцності на пенетрометри АР-4/1) досліджень були використані загальноприйняті та стандартні методики

The Role of Vascular Endothelial Growth Factor and Antithrombin III In The Pathogenesis of the Ovarian Hyperstimulation Syndrome

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of controlled ovarian hyperstimulation (COH). Its pathogenesis is not clarified yet. In the recent years a number of studies focused on the vascular endothelial growth factor (VEGF) and antihtrombin III (AT III) indicators. VEGF is homodimeric, heparin-binding glycoprotein, stimulating vascular permeability. Antithrombin III is protease inhibitor of activated clotting factors. This study aimed at examining the VEGF-A165 and AT III indicators with two OHSS patients. Two methods were used for the determination of the indicators of VEGF-A165 and AT III: ELISA for VEGF and chromogenic assay for ATT III. Kits of R/D Systems and American Diagnostica Inc. were used to estimate VEGF and AT III indicators in serum and plasma. There were higher indicators of VEGF-A165 (180pg/ml) and reduction of AT III indicators (48%) in the patient with a severe form of OHSS than in the control group while these indicators were normal in the patient with a moderate form of OHSS. Our results confirmed some published data concerning the importance of VEGF and AT III in the genesis of OHSS. This study should include a larger group of patients in order tofollow-up statistically and authentically the variations of the indicators of both factors and their importance for OHSS