Evaluation of artificial reforestation efforts in the ribbon forest zone of Altai Krai

The ribbon forest zone of Altai Krai is located in the Kulunda Steppe and on the Priobskoye Plateau. The climate of this region is characterized by extreme aridity. Due to the harsh climate and the importance of the ribbon forests for the environmental sustainability of the region, artificial reforestation is an integral part of the regional forest management. Forest stands of artificial origin currently occupy a large area within the ribbon forest zone, as evidenced by forest inventory data. However, due to the fact that surveys are not conducted simultaneously on the whole territory of Altai Krai, and that they miss some of the forest management units, forest inventory data do not provide an up-to-date assessment of artificial reforestation efforts. Our project attempted to update the existing data of forest resource assessments and evaluate the results of artificial reforestation efforts in the ribbon forest zone of Altai Krai. This article presents data on the distribution of the artificially reforested area by predominant species and type of growing conditions, and the distribution of the growing stock of the artificially established stands by age and type of forest growing conditions. © 2019 IOP Publishing Ltd. All rights reserved

Compilation and analysis of charge asymmetry measurements from electron and positron scattering on nucleon and nuclei

World data on the lepton-charge asymmetry in the elastic and inelastic lepton scattering off the proton and nuclei are compiled and discussed. After reviewing the published results, we compare the elastic data to a model calculation of the two-photon exchange mechanism. We show that the existing data do not provide any evidence for the two-photon contribution. At significance level 0.05 the data allow to exclude the two-photon exchange as an explanation for the difference between Rosenbluth and polarization measurements of proton electromagnetic form factors.Comment: 20 pages, 7 figures 2 table

The surface electrical heterogeneity of the membranes with the different degree of cation-exchanger dispersity

The work is supported by the grant of the President of the Russian Federation MK-925.2018.3. The authors are grateful to the «MEGA» a.s. company (Czech Republic) and its owner Mr. L. Novak for providing experimental samples of the Ralex CM Pes sulfocation-exchange membranes. Microphotographs of the membranes surface were obtained at the CCUSE of VSU

Azimuthal expansion of high-latitude auroral arcs

International audienceWe used the TV auroral observations in Barentsburg (78.05° N 14.12° E) in Spitsbergen archipelago, together with the data of the CUTLASS HF radars and the POLAR satellite images to study azimuthal (in the east-west direction) expansion of the high-latitude auroral arcs. It is shown that the east or west edge of the arc moved in the same direction as the convection flow, westward in the pre-midnight sector and eastward in the post-midnight sector. The velocity of arc expansion was of the order of 2.5 km/s, which is 2?3 times larger than the convection velocity measured in the arc vicinity and 2?3 times smaller than the velocity of the bright patches propagating along the arc. The arc expanded from the active auroras seen from the POLAR satellite around midnight as a region of enhanced luminosity, which might be the auroral bulge or WTS. The pole- or equatorward drift of the arcs occurred at the velocity of the order of 100 m/s that was close to the convection velocity in the same direction. These experimental results can be well explained in terms of the interchange (or flute) instability

Comparative productivity of artificial and natural forest stands in the belt pine forests of Altay

Using the indicator of the initial density G:H, tables of the growth course of natural and artificial self-tinning pine stands growing in conditions such as dry pine forest of gentle hills type were compiled. It was found that the productivity of self-thinning artificial stands is higher than natural ones only up to III-IV age classes, after which their productivity is equal or less than the productivity on natural stands. The most productive artificial stands are those with average density, however, the largest average diameter is possessed by rare tree stands. In the artificial pine forests in the belt pine stands of the Altai Territory, it is necessary to carry out thinning in a timely manner by using a grass-root method. This will get rid of oppressed trees and increase the growth of trees in diameter, that in turn will increase the yield of commercial timber at the ripeness age. © Published under licence by IOP Publishing Ltd

Global Analysis of Data on the Proton Structure Function g1 and Extraction of its Moments

Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g1 in the range 0.17 < Q2 < 30 (GeV/c)**2. We compute for the first time low-order moments of g1 and study their evolution from small to large values of Q2. The analysis includes the latest data on both the unpolarized inclusive cross sections and the ratio R = sigmaL / sigmaT from Jefferson Lab, as well as a new model for the transverse asymmetry A2 in the resonance region. The contributions of both leading and higher twists are extracted, taking into account effects from radiative corrections beyond the next-to-leading order by means of soft-gluon resummation techniques. The leading twist is determined with remarkably good accuracy and is compared with the predictions obtained using various polarized parton distribution sets available in the literature. The contribution of higher twists to the g1 moments is found to be significantly larger than in the case of the unpolarized structure function F2.Comment: 18 pages, 13 figures, to appear in Phys. Rev.

РORTABLE GENERATOR OF SYNCHRONIZING PULSES

A portable digital generator of synchronizing (delayed) pulses has been developed. This device is compact and battery powered, which simplifies the tuning of experimental setups and allows them to be used outside the laboratory

Application of Resonant Converters for Charging Capacitive Energy Storages by the Example of the High Voltage Pulse Generator «RADAN 303»

The article discusses aspects of the operation of the resonant converter and the applied circuitry solutions to improve the stability of work of a powerful pulse generator «RADAN 303»

Interaction of solar neutrinos with 98,100^{98,100}Mo isotopes and the influence of nuclear resonances

The process of neutrino interaction with $^{98}$Mo and $^{100}$Mo isotopes is studied taking into consideration the effect of charge-exchange resonances. The experimental data on the strength functions $S(E)$ obtained in charge-exchange reactions $(p; n)$ and $(^3\mathrm{He}, t)$ and the strength functions $S(E)$ calculated within the theory of finite Fermi systems were used. We studied the effect of the resonance structure of $S(E)$ on the cross sections for solar-neutrino. We investigated the contribution of each high-lying resonance to the capture cross section $\sigma(E_{\nu})$. The contributions of all components of the solar neutrino spectrum are calculated. We estimate the contribution of different components of solar neutrinos as the background for the double-beta decay experiments on $^{100}$Mo.Comment: 17 pages, 7 figure

The HPS electromagnetic calorimeter

The Heavy Photon Search experiment (HPS) is searching for a new gauge boson, the so-called “heavy photon.” Through its kinetic mixing with the Standard Model photon, this particle could decay into an electron-positron pair. It would then be detectable as a narrow peak in the invariant mass spectrum of such pairs, or, depending on its lifetime, by a decay downstream of the production target. The HPS experiment is installed in Hall-B of Jefferson Lab. This article presents the design and performance of one of the two detectors of the experiment, the electromagnetic calorimeter, during the runs performed in 2015–2016. The calorimeter's main purpose is to provide a fast trigger and reduce the copious background from electromagnetic processes through matching with a tracking detector. The detector is a homogeneous calorimeter, made of 442 lead-tungstate (PbWO4) scintillating crystals, each read out by an avalanche photodiode coupled to a custom trans-impedance amplifier