CCD Measurements of Double and Multiple Stars at NAO Rozhen. IV

Using the 2 m telescope of the Bulgarian National Astronomical Observatory at Rozhen observations of 30 double or multiple stars were carried out during two half nights on July 20and 21, 2009. This is the fourth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. In this paper we present the results for the position angle and separation for 23 double and 5 multiple stars (35 pairs) which could have been measured

Special Classes of Orthogonal Polynomials and Corresponding Quadratures of Gaussian Type

MSC 2010: 33C47, 42C05, 41A55, 65D30, 65D32In the first part of this survey paper we present a short account on some important properties of orthogonal polynomials on the real line, including computational methods for constructing coefficients in the fundamental three-term recurrence relation for orthogonal polynomials, and mention some basic facts on Gaussian quadrature rules. In the second part we discuss our Mathematica package Orthogonal Polynomials (see [2]) and show some applications to problems with strong nonclassical weights on (0;+1), including a conjecture for an oscillatory weight on [¡1; 1]. Finally, we give some new results on orthogonal polynomials on radial rays in the complex plane

The effect of lipophilicity on the antibacterial activity of some 1-benzylbenzimidazole derivatives

In the present paper, the antibacterial activity of some 1-benzylbenzimidazole derivatives were evaluated against the Gram-negative bacteria Escherichia coli. The minimum inhibitory concentration was determined for all the compounds. Quantitative structure–activity relationship (QSAR) was employed to study the effect of the lipophilicity parameters (log P) on the inhibitory activity. Log P values for the target compounds were experimentally determined by the “shake-flask” method and calculated by using eight different software products. Multiple linear regression was used to correlate the log P values and antibacterial activity of the studied benzimidazole derivatives. The results are discussed based on statistical data. The most acceptable QSAR models for the prediction of the antibacterial activity of the investigated series of benzimidazoles were developed. High agreement between the experimental and predicted inhibitory values was obtained. The results of this study indicate that the lipophilicity parameter has a significant effect on the antibacterial activity of this class of compounds, which simplifies the design of new biologically active molecules

YIELD AND YIELD COMPONENTS ON SOME WHEAT VARIETIES GROWN IN ALEKSINAC REGION

Yield and yield components of 5 wheat varieties (Kruna, Toplica, Zvezdana, Etida, Angelina) in Aleksinac region (Serbia) were analysed. The experiment was performed in randomized block design in 3 replications on the experimental field in area of Aleksinac city. The results showed relatively high yields in all varieties. The general average yield was 6140 kg ha-1. The highest average yield varied from 6858 kg ha-1 in cultivar Zvezdana to 5050 kg ha-1 in Toplica. The cultivar Kruna showed lowest number of productive stems per square meter – 572, and largest number in Zvezdana and Angelina, with an average of 658 and 641, respectively. Average longest spike was found in variety Angelina 12.4 cm, and shortest in Toplica (9.8 cm). The average number of spikelets per spike for all cultivars was 19.4. Cultivar Angelina showed biggest number (21.1), and Kruna smallest number (17.9). The biggest number of grains per spike was obtained in cultivar Etida (54.8), and lowest in Zvezdana (51.4). During the examination, the highest average value for hectoliter weight is obtained in variety Zvezdana (78.3 kg hl-1), and lowest in Toplica (75.4 kg hl-1). From the data on yield and yield components, it can be concluded that all tested varieties can be grown in the region of Aleksinac, with preference to varieties Zvezdana and Etida

Theory of Andreev reflection in a two-orbital model of iron-pnictide superconductors

A recently developed theory for the problem of Andreev reflection between a normal metal (N) and a multiband superconductor (MBS) assumes that the incident wave from the normal metal is coherently transmitted through several bands inside the superconductor. Such splitting of the probability amplitude into several channels is the analogue of a quantum waveguide. Thus, the appropriate matching conditions for the wave function at the N/MBS interface are derived from an extension of quantum waveguide theory. Interference effects between the transmitted waves inside the superconductor manifest themselves in the conductance. We provide results for a FeAs superconductor, in the framework of a recently proposed effective two-band model and two recently proposed gap symmetries: in the sign-reversed s-wave ($\Delta\cos(k_x)\cos(k_y)$) scenario resonant transmission through surface Andreev bound states (ABS) at nonzero energy is found as well as destructive interference effects that produce zeros in the conductance; in the extended s-wave ($\Delta[\cos(k_x)+\cos(k_y)]$) scenario no ABS at finite energy are found.Comment: 4 pages, 5 figure

A complete characterization of plateaued Boolean functions in terms of their Cayley graphs

In this paper we find a complete characterization of plateaued Boolean functions in terms of the associated Cayley graphs. Precisely, we show that a Boolean function $f$ is $s$-plateaued (of weight $=2^{(n+s-2)/2}$) if and only if the associated Cayley graph is a complete bipartite graph between the support of $f$ and its complement (hence the graph is strongly regular of parameters $e=0,d=2^{(n+s-2)/2}$). Moreover, a Boolean function $f$ is $s$-plateaued (of weight $\neq 2^{(n+s-2)/2}$) if and only if the associated Cayley graph is strongly $3$-walk-regular (and also strongly $\ell$-walk-regular, for all odd $\ell\geq 3$) with some explicitly given parameters.Comment: 7 pages, 1 figure, Proceedings of Africacrypt 201

Large-Scale MDO of a Small Satellite using a Novel Framework for the Solution of Coupled Systems and their Derivatives

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106515/1/AIAA2013-1599.pd

Quantum Graphs II: Some spectral properties of quantum and combinatorial graphs

The paper deals with some spectral properties of (mostly infinite) quantum and combinatorial graphs. Quantum graphs have been intensively studied lately due to their numerous applications to mesoscopic physics, nanotechnology, optics, and other areas. A Schnol type theorem is proven that allows one to detect that a point belongs to the spectrum when a generalized eigenfunction with an subexponential growth integral estimate is available. A theorem on spectral gap opening for ``decorated'' quantum graphs is established (its analog is known for the combinatorial case). It is also shown that if a periodic combinatorial or quantum graph has a point spectrum, it is generated by compactly supported eigenfunctions (``scars'').Comment: 4 eps figures, LATEX file, 21 pages Revised form: a cut-and-paste blooper fixe