Existence of Self-sustained Oscillations in an Ocean Circulation Box Model with Turbulent Fluxes

Box-models are important for qualitative description of thermohaline circulation. Their bifurcation analysis helps to understand possible mechanisms for the loss of stability. So far, bifurcations in box-models have been studied numerically, except for the saddle-node bifurcation in the Stommel type models. We consider a box-model with turbulent fluxes. We prove that a rapid growth of the transfer function can lead to existence of a limit cycle. This limit cycle collapses to a steady state as the transfer function approaches the step function

Structural, Dimensional and Thermoelectric Properties of Melt Spun p-Bi0,5Sb1,5Te3

Thermoelectric melt spun p-Bi0,5Sb1,5Te3 powders were obtained and their structural properties were studied. It was established that the crystallites constituting the powder particles are nanofragmented. Powders were compacted by vacuum hot pressing and spark plasma sintering. Thermoelectric characteris-tics of obtained samples were investigated in 100 K-700 K temperature range. The samples prepared by above methods posses low thermal conductivity while retaining values of the Seebeck coefficient and elec-trical conductivity comparable to conventional crystallized materials, thereby thermoelectric efficiency ZT reaches 1.05-1.15 at 330-350 K. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3636

On quantization of singular varieties and applications to D-branes

We calculate the ring of differential operators on some singular affine varieties (intersecting stacks, a point on a singular curve or an orbifold). Our results support the proposed connection of the ring of differential operators with geometry of D-branes in (bosonic) string theory. In particular, the answer does know about the resolution of singularities in accordance with the string theory predictions.Comment: LaTeX2e, 17 pages, misprints correcte

Developing of modern cultivation technology of organic potatoes

Medium term field experiment demonstrates the effectiveness of biological ways to increase potatoes yield on the sod-podzolic, light loamy soil. The effects of the following two groups of factors were studied: 1. The level of mineral nutrition provided by compost; 2. Microbiological pant protection product (bio preparations): Flavobacterin which has N fixer attribute and Vitaplan and Kartofen, which have bio fungicide features. Potatoes varieties ‘Nevsky’ and ‘Udacha’ were cultivated. The compost was applied in the dose range from 0 to 160 kg N ha-1 . Treatment with bio-preparations was carried out by potato tubers during planting and leaves during the growing season. Weeds were removed mechanically. Weather conditions had a significant impact on the formation of the crop. The average yield of standard potato tubers for 2017–2018 ranged from 14.1 to 29.3 t ha-1 . The use of both microbiological preparations and compost gave approximately the same effect and increased yields by 35–37% compared to the control. The use of compost together with bio-preparations provided an output of 27.6–29.3 t ha-1of potatoes. In 2019, the joint use of compost and biopreparations allowed to reach a yield of 40 tons ha-1 of marketable potatoes. On the basis of the obtained data, the mathematical dependences of the yield of potatoes on the dose of compost, the type of biological preparation and the complex indicator of the year conditions were determined

Top quark threshold production in γγ\gamma\gamma collision in the next-to-leading order

The total cross section of the top quark-antiquark pair production near threshold in $\gamma\gamma$ collision is computed analytically up to the next-to-leading order in perturbative and nonrelativistic expansion for general photon helicity. The approximation includes the first order corrections in the strong coupling constant and the heavy quark velocity to the nonrelativistic Coulomb approximation.Comment: 27 pages Latex, misprints correcte

Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer

Aim:To assess the frequency and spectrum of chromosome aberrations and micronuclei in peripheral blood lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer during the course of neutron therapy. Materials and Methods: Samples of peripheral blood were obtained from 9 patients with parotid salivary gland tumors (T3N0–3M0) and 8 patients with relapse of breast cancer before, after first fraction and at the end of neutron therapy. The treatment course specified 5.5–8.4 Gy (equivalent to 23–44 Gy of photon irradiation) with 1.3–2.2 Gy per fraction for patients with parotid salivary gland tumors and 4,8–8.0 Gy (equivalent to 30–40 Gy of photon irradiation) with 1.6 Gy per fraction for patients with relapse of breast cancer. Control group established for conventional cytogenetic analysis consisted of 15 healthy persons. Assessment of chromosome aberrations frequency was performed on routinely stained metaphase plates. Lymphocytes from the same patients were analyzed by micronucleus test in combination with fluorescent in situ hybridization (FISH) using pancentromeric DNA probe. Results: Level of chromosome aberrations and micronuclei significantly increased in lymphocytes of patients from both groups during neutron therapy (P < 0.05). This increase was mainly due to chromosome-type aberrations and centromere-negative micronuclei. The prevalent types of aberrations are in agreement with theoretical mechanisms of neutron effects on cells. Conclusion: Cytogenetic effects of fast neutron therapy in lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer were observed. A positive dynamics of radiation-induced chromosomal damages formation during the course was denoted in lymphocytes of cancer patients in both groups

M(Bc∗)−M(Bc)M(B^*_c)-M(B_c) Splitting from Nonrelativistic Renormalization Group

We compute the hyperfine splitting in a heavy quarkonium composed of different flavors in next-to-leading logarithmic approximation using the nonrelativistic renormalization group. We predict the mass difference of the vector and pseudoscalar charm-bottom mesons to be $M(B^*_c)-M(B_c)=46 \pm 15 {(\rm th)} {}^{+13}_{-11} (\delta\alpha_s)$ MeV.Comment: Eq.(22) and Appendix corrected, numerical results slightly changed. arXiv admin note: text overlap with arXiv:hep-ph/031208

Modeling Cavitation in ICE Pistons Made with Isothermal Forging

Possible causes for cavitations in parts made with an Al-Si eutectic alloy AK12D (AlSi12) were explored with mathematical and physical modeling with involved acoustic emission. Pores were formed from micro-cracks, which appear during the early stages of a deformation process, with the help of micro-stresses appearing at phase boundaries (Al/Si interface) due to thermal expansion. At the design stage of isothermal forgings of such products it is recommended to provide a scheme of the deformed shape, which is under uniform compression, to compensate for the inter-phase stresses

Ultrasoft contribution to quarkonium production and annihilation

We compute the third-order correction to electromagnetic S-wave quarkonium production and annihilation rates due to the emission and absorption of an ultrasoft gluon. Our result completes the analysis of the non-relativistic quarkonium bound-state dynamics in the next-to-next-to-next-to-leading order. The impact of the ultrasoft correction on the Upsilon(1S) leptonic width and the top quark-antiquark threshold production cross section is estimated.Comment: 10 page