Theory of pattern-formation of metallic microparticles in poorly conducting liquid

We develop continuum theory of self-assembly and pattern formation in metallic microparticles immersed in a poorly conducting liquid in DC electric field. The theory is formulated in terms of two conservation laws for the densities of immobile particles (precipitate) and bouncing particles (gas) coupled to the Navier-Stokes equation for the liquid. This theory successfully reproduces correct topology of the phase diagram and primary patterns observed in the experiment [Sapozhnikov et al, Phys. Rev. Lett. v. 90, 114301 (2003)]: static crystals and honeycombs and dynamic pulsating rings and rotating multi-petal vortices.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

Swelling-collapse transition of self-attracting walks

We study the structural properties of self-attracting walks in d dimensions using scaling arguments and Monte Carlo simulations. We find evidence for a transition analogous to the \Theta transition of polymers. Above a critical attractive interaction u_c, the walk collapses and the exponents \nu and k, characterising the scaling with time t of the mean square end-to-end distance ~ t^{2 \nu} and the average number of visited sites ~ t^k, are universal and given by \nu=1/(d+1) and k=d/(d+1). Below u_c, the walk swells and the exponents are as with no interaction, i.e. \nu=1/2 for all d, k=1/2 for d=1 and k=1 for d >= 2. At u_c, the exponents are found to be in a different universality class.Comment: 6 pages, 5 postscript figure

The efficiency of Profort additive in feeding cows during the period of increasing the milk yield

The article provides data on the use of Profort feed probiotic additive containing strains of Enterococcus faecium and Bacillus subtilis bacteria in feeding cows during the period of increasing the milk yield. The research was conducted in 2019 on the basis of Agricultural Production Cooperative Collective farm "Iskra", Kirov region. Two groups of highly productive black-and-white motley cows with the average milk yield of 7500 kg for a lactation of 20 animals each were formed for the experiment. The morphological composition and immuno-biochemical parameters of blood of the experimental animals as well as milk productivity and quality indicators of milk were studied, the economic efficiency of Profort probiotic additive use was calculated. It has been established that the inclusion of Profort additive into the animal diet at a dose of 30 g per head per day during 80 days of the period of increasing the milk yield contributes to the normalization of metabolic processes in their bodies, increasing the average daily milk yield by 9.04 – 12.86% (P<0.05), an increase in the percentage of fat and protein in milk by 0.03-0.10%, respectively, compared with the similar indicators of animals in the control group. When using Profort, from the cows of the experimental group in the first three months of lactation 72785.08 kg of milk in a basic fat content of 3.4% were ob-tained, that was 10580.37 kg of milk more as compared with the milk yield of animals from the control group for the same period (62204.71 kg). It allowed to increase the revenue from the sale of milk by 17.01%, to reduce the cost of production of 1 kg of milk by 2 rubles or 11.76% and to get 6.04 rubles of additional profit for each ruble of additional costs. The increase in profit and reduction in the cost of milk production contributed to an increase in profitability by 18.01%

Self-Attracting Walk on Lattices

We have studied a model of self-attracting walk proposed by Sapozhnikov using Monte Carlo method. The mean square displacement $\sim t^{2\nu}$ and the mean number of visited sites $\sim t^{k}$ are calculated for one-, two- and three-dimensional lattice. In one dimension, the walk shows diffusive behaviour with $\nu=k=1/2$. However, in two and three dimension, we observed a non-universal behaviour, i.e., the exponent $\nu$ varies continuously with the strength of the attracting interaction.Comment: 6 pages, latex, 6 postscript figures, Submitted J.Phys.

Interacting circular nanomagnets

Regular 2D rectangular lattices of permalloy nanoparticles (40 nm in diameter) were prepared by the method of the electron lithography. The magnetization curves were studied by Hall magnetometry with the compensation technique for different external field orientations at 4.2K and 77K. The shape of hysteresis curves indicates that there is magnetostatic interaction between the particles. The main peculiarity is the existence of remanent magnetization perpendicular to easy plain. By numerical simulation it is shown, that the character of the magnetization reversal is a result of the interplay of the interparticle interaction and the magnetization distribution within the particles (vortex or uniform).Comment: 16 pages, 8 figure

Unified approach to photo and electro-production of mesons with arbitrary spins

A new approach to identify the independent amplitudes along with their partial wave multipole expansions, for photo and electro-production is suggested,which is generally applicable to mesons with arbitrary spin-parity. These amplitudes facilitate direct identification of different resonance contributions.Comment: 11 page

New data on OZI rule violation in bar{p}p annihilation at rest

The results of a measurement of the ratio R = Y(phi pi+ pi-) / Y(omega pi+ pi-) for antiproton annihilation at rest in a gaseous and in a liquid hydrogen target are presented. It was found that the value of this ratio increases with the decreasing of the dipion mass, which demonstrates the difference in the phi and omega production mechanisms. An indication on the momentum transfer dependence of the apparent OZI rule violation for phi production from the 3S1 initial state was found.Comment: 11 pages, 3 PostScript figures, submitted to Physics Letter

Measurements of the reaction pˉp→ϕη\bar{p}p \to \phi \eta of antiproton annihilation at rest at three hydrogen target densities

The proton-antiproton annihilation at rest into the $\phi\eta$ final state was measured for three different target densities: liquid hydrogen, gaseous hydrogen at NTP and at a low pressure of 5 mbar. The yield of this reaction in the liquid hydrogen target is smaller than in the low-pressure gas target. The branching ratios of the $\phi\eta$ channel were calculated on the basis of simultaneous analysis of the three data samples. The branching ratio for annihilation into $\phi\eta$ from the $^3S_1$ protonium state turns out to be about ten times smaller as compared to the one from the $^1P_1$ state.Comment: 10 pages, 3 Postscript figures. Accepted by Physics Letters

First Measurement of the Transverse Spin Asymmetries of the Deuteron in Semi-Inclusive Deep Inelastic Scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6-LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.Comment: 6 pages, 2 figure

The Polarised Valence Quark Distribution from semi-inclusive DIS

The semi-inclusive difference asymmetry A^{h^{+}-h^{-}} for hadrons of opposite charge has been measured by the COMPASS experiment at CERN. The data were collected in the years 2002-2004 using a 160 GeV polarised muon beam scattered off a large polarised ^6LiD target and cover the range 0.006 < x < 0.7 and 1 < Q^2 < 100 (GeV/c)^2. In leading order QCD (LO) the asymmetry A_d^{h^{+}-h^{-}} measures the valence quark polarisation and provides an evaluation of the first moment of Delta u_v + Delta d_v which is found to be equal to 0.40 +- 0.07 (stat.) +- 0.05 (syst.) over the measured range of x at Q^2 = 10 (GeV/c)^2. When combined with the first moment of g_1^d previously measured on the same data, this result favours a non-symmetric polarisation of light quarks Delta u-bar = - Delta d-bar at a confidence level of two standard deviations, in contrast to the often assumed symmetric scenario Delta u-bar = Delta d-bar = Delta s-bar = Delta s.Comment: 7 pages, 3 figures, COMPASS, revised: details added, author list update