Realistic Tunneling States for the Magnetic Effects in Non-Metallic Real Glasses

The discovery of magnetic and compositional effects in the low temperature properties of multi-component glasses has prompted the need to extend the standard two-level systems (2LSs) tunneling model. A possible extension \cite{Jug2004} assumes that a subset of tunneling quasi-particles is moving in a three-welled potential (TWP) associated with the ubiquitous inhomogeneities of the disordered atomic structure of the glass. We show that within an alternative, cellular description of the intermediate-range atomic structure of glasses the tunneling TWP can be fully justified. We then review how the experimentally discovered magnetic effects can be explained within the approach where only localized atomistic tunneling 2LSs and quasi-particles tunneling in TWPs are allowed. We discuss the origin of the magnetic effects in the heat capacity, dielectric constant (real and imaginary parts), polarization echo and SQUID magnetization in several glassy systems. We conclude by commenting on a strategy to reveal the mentioned tunneling states (2LSs and TWPs) by means of atomistic computer simulations and discuss the microscopic nature of the tunneling states in the context of the potential energy landscape of glass-forming systems.Comment: 48 pages, 27 figures; mini-review for the Proceedings of the XIV International Workshop on Complex Systems (Fai della Paganella, Trento, March 2015) (submitted to Phil.Mag.). arXiv admin note: text overlap with arXiv:cond-mat/0210221 by other author

Bernoulli substitution in the Ramsey model: Optimal trajectories under control constraints

We consider a neoclassical (economic) growth model. A nonlinear Ramsey equation, modeling capital dynamics, in the case of Cobb-Douglas production function is reduced to the linear differential equation via a Bernoulli substitution. This considerably facilitates the search for a solution to the optimal growth problem with logarithmic preferences. The study deals with solving the corresponding infinite horizon optimal control problem. We consider a vector field of the Hamiltonian system in the Pontryagin maximum principle, taking into account control constraints. We prove the existence of two alternative steady states, depending on the constraints. A proposed algorithm for constructing growth trajectories combines methods of open-loop control and closed-loop regulatory control. For some levels of constraints and initial conditions, a closed-form solution is obtained. We also demonstrate the impact of technological change on the economic equilibrium dynamics. Results are supported by computer calculations

Kisspeptin is Testosterone independent regulator of Sexual Motivation in Male Rats

Kisspeptin is the peptide product of the KISS-1 gene and endogenous agonist for the Kiss1 receptor. It is well known that kisspeptin acts centrally, and stimulates the secretion of gonadoliberin (GnRH). Further, Kisspeptin also interacts with other neuropeptides such as neurokinin B and dynorphin to regulate GnRH pulse generation and plays a key role in sexual behavior. This study aimed to evaluate the effect of kisspeptin on male rats' sexual motivation and its dependence on testosterone levels. In this study total of 50 copulation naive male Wistar rats were collected and divided into 5 groups (10 rats in each group), among these first group received only saline (control), the second group has been given 20μg buserelin acetate (GnRH analogue), the third group has been given intranasally kisspeptin-10 (3ng), the fourth has been received intraperitoneally kisspeptin-10 (30ng) and the fifth group has been given Yoquimbine 200 µg. Behavioral effects were registered in the open-field reward-proximity chamber with a female in the estrous phase of the cycle over the transparent perforated wall for 10 minutes in red light. Blood samples were collected from the tail vein after 30 minutes of the substance administration and in the collected blood samples, testosterone concentration was measured by the ELISA method. All animal groups were compared with each other by the ANOVA test and correspondent “post hoc” paired tests of Newman–Kruskall– Wallis test and Dunn’s test. Intranasal administration of buserelin acetate increased the concentration of testosterone but did not affect sexual motivation in rats. Further, intraperitoneal administration of Kisspeptin-10 enhances testosterone concentration and sexual motivation. While intranasal administration of kisspeptin-10 didn’t enhance testosterone level but increased sexual motivation. Results of this study showed some effects of kisspeptin along with the independent regulation of steroids

Application of Computer Simulation to Study the Features of the Austenite Isothermal Transformation in Steels

An algorithm was developed for the simulation of a phase transition in solid state which makes it possible to obtain the kinetic curves of transformation under different initial conditions (the number and arrangement of new phase nuclei, the distance between the nearest nuclei). The simulation results were analyzed using the KolmogorovJohnson-Mehl-Avrami equation and the corresponding coefficients were determined. The correlation between the simulation results and the experimental kinetics of the austenite isothermal transformation in alloyed steels was shown.     Keywords: computer simulation; modeling; phase transformation; kinetics; KJMA equation; logistic function; steel

Design of a gas cell for laser wakefield acceleration of electrons

Laser-wakefield acceleration of electrons in a gas cell is considered. The OpenFOAM package is used to study the influence of the parameters of the cell on the density profile. Particle-in-cell simulations of laser wakefield aсceleration are performed for a 150 TW laser pulse, accelerated electrons with energies above 1 GeV are observed. A two-stage gas cell is investigated.Розглянуто лазерно-плазмове прискорення електронів у газовій комірці. За допомогою пакета OpenFOAM досліджено вплив параметрів середовища на профіль густини. Проведено моделювання методом «частинок у комірці» лазерно-плазмового прискорення для лазерного імпульсу потужністю 150 ТВт, при цьому спостерігалися прискорені електрони з енергією більше 1 ГеВ. Досліджена двостадійна газова комірка.Рассмотрено лазерно-плазменное ускорение электронов в газовой ячейке. При помощи пакета OpenFOAM исследовано влияние параметров ячейки на профиль плотности. Проведено моделирование методом «частиц в ячейках» лазерно-плазменного ускорения для лазерного импульса мощностью 150 ТВт, при этом наблюдались ускоренные электроны с энергией более 1 ГэВ. Исследована двухстадийная газовая ячейка

Reversible reorganization of the chlorophyll-protein complexes of photosystem II in cyanobacterium cells in the dark ag

AbstractA new emission band at 673 nm was detected in the low-temperature fluorescence spectrum of dark-adapted cyanobacteria Gloeotrichia raciborski. The excitation spectrum of this band was close to the absorbance of the isolated reaction centre of photosystem II. The relative intensities of the bands of chlorophyll and pheophytin in this spectrum showed the relative concentrations of these pigments to be about 3:1. The intensity of the band increased with darkness (half-time about 2 h). Under illumination the band rapidly disappeared (half-time about 60 s). The appearance of a 673 nm band in the dark and its disappearance in the light were accompanied by a decrease, and, respectively, an increase in the fluorescence of the PS II band at 697 nm

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