356 research outputs found

    Azimuthal patterns in planetesimal circumstellar disks

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    Ways of formation of azimuthal resonant patterns in circumstellar planetesimal disks with planets are considered. Our analytical estimates and massive numerical experiments show that the disk particles that initially reside in zones of low-order mean-motion resonances with the planet may eventually concentrate into potentially observable azimuthal patterns. The structuring process is rapid, usually taking ~100 orbital periods of the planet. It is found that the relative number of particles that retain their resonant position increases with decreasing the mass parameter μ\mu (the ratio of masses of the perturbing planet and the parent star), but a significant fraction of the particle population is always removed from the disk due to accretion of the particles onto the star and planet, as well as due to their transition to highly elongated and hyperbolic orbits. Expected radio images of azimuthally structured disks are constructed. In the considered models, azimuthal patterns associated with the 2:1 and 3:2 resonances are most clearly manifested; observational manifestations of the 1:2 and 2:3 resonances are also possible.Comment: 24 pages, 8 figures. Accepted for publication in Astronomy Letter

    Minimization of Fungicidal Applications Against Potato Late Blight in the North Caucasian Region: Use of the “Agrodozor” System

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    Late blight is considered to be the most devastating potato disease, which control requires application of fungicides able to significantly contaminate the environment and accumulate in agricultural products. Pesticide load on potato fields can be reduced via optimization of the scheme of protective treatments. Such optimization can be performed using a mathematical simulator describing the dependence of late blight-caused yield losses on the weather data and an “Agrodozor” decision support system (DSS). The performed analysis of a situation in the regions of the North Caucasus allowed us to determine three zones differing in the disease harmfulness and characterized by potential yield losses at the level of <10, 10-20, and >20 % and the probability of disease appearance in field during 30, 77, and 90 % of seasons, respectively. Using the “Agrodozor” DSS, we calculated the optimum dates of fungicidal treatments for these zones and showed that, comparing to the commonly used routine scheme of treatments, the use of this DSS provides a significant reduction of the number of such treatments and, therefore, the corresponding costs for their arrangement, as well as reduction of the total toxicity index of the required protective measures

    Actinic reticuloid: case report

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    This article is about the case of actinic reticuloid — the rare dermatosis which clinical presentation is similar to atopic dermatitis, T-cell lymphoma. Good treatment effect was obtained by long cycles (2 cycles for 3 months) of hydroxychloroquine and sun protective therapy included sunscreens SPF 50, nicotinic acid, sun-safe clothes which blocked ultraviolet radiation without any glucocorticosteroid drugs and cytostatic treatment

    The first result of the neutrino magnetic moment measurement in the GEMMA experiment

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    The first result of the neutrino magnetic moment measurement at the Kalininskaya Nuclear Power Plant (KNPP) with the GEMMA spectrometer is presented. An antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed 13.9 m away from the 3 GW reactor core is used in the spectrometer. The antineutrino flux is 2.73×1013νe/cm2/s2.73\times 10^{13} \nu_e / cm^2 / s. The differential method is used to extract the ν\nu-e electromagnetic scattering events. The scattered electron spectra taken in 6200 and 2064 hours for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment μν<5.8×1011\mu_\nu < 5.8\times 10^{-11} Bohr magnetons at 90{%} CL is derived from the data processing.Comment: 9 pages, 10 figures, 2 table
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