680 research outputs found

    On the Differential Geometry of GLq(11)GL_q(1| 1)

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    The differential calculus on the quantum supergroup GLq(11)_q(1| 1) was introduced by Schmidke {\it et al}. (1990 {\it Z. Phys. C} {\bf 48} 249). We construct a differential calculus on the quantum supergroup GLq(11)_q(1| 1) in a different way and we obtain its quantum superalgebra. The main structures are derived without an R-matrix. It is seen that the found results can be written with help of a matrix R^\hat{R}Comment: 14 page

    Determination of the antioxidant properties of ethanol and water extracts from different parts of Teucrium parviflorum Schreber

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    This study was designed to examine in vitro antioxidant of extracts of Teucrium parviflorum Schreber. The plants were extracted successively in ethanol and water using soxhlet-apparatus. They were screened for possible antioxidant activity using the ABTS• (2,2'-azino-bis-(3-ethylbenzothiazoline-6- sulphonic acid)) radical scavenging capacity, DPPH• (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity, superoxide anion radical scavenging capacity, hydrogen peroxide scavenging capacity, reducing power and metal chelating activities. These various antioxidant activities were compared with standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α- tocopherol. The extracts of T. parviflorum showed strong antioxidant activity and effective antioxidant assay. This antioxidant property depends on concentration and increase with increased amount of sample. In addition, total phenolic compounds in the extracts of T. parviflorum were determined as pyrocatecol equivalents. The results obtained in the present study indicated that T. parviflorum is a potential source of natural antioxidant.Keywords: Teucrium parviflorum, antioxidant activity, medicinal plants, extract, flower, leaves

    h-deformation of Gr(2)

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    The hh-deformation of functions on the Grassmann matrix group Gr(2)Gr(2) is presented via a contraction of Grq(2)Gr_q(2). As an interesting point, we have seen that, in the case of the hh-deformation, both R-matrices of GLh(2)GL_h(2) and Grh(2)Gr_h(2) are the same

    Variance reduction techniques: Experimental comparison and analysis for single systems

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    We provide a thorough analysis of the effectiveness of different Variance Reduction Techniques (VRTs). We consider both stand-alone and combined applications of two input techniques, Antithetic Variates (AV) and Latin Hypercube Sampling (LHS), and two output techniques, Control Variates (CV) and Poststratified Sampling (PS). Previous research in the area mainly focuses on asymptotic variance reduction. In this experimental study, we measure the performance of VRTs under finite simulation run lengths and analyze their effects. Our findings show that the asymptotic variance reduction results do not readily apply to finite-length simulations. We consider three different types of systems (M/M/1, serial production line and (s, S) inventory control systems) and compare the VRTs under various experimental conditions. We observe that a variance reduction cannot be guaranteed for every instance a VRT is applied. Our results also indicate that the output VRTs (CV, PS) are better than input VRTs (AV, LHS) on the average for the single systems considered in this study. More interestingly, the less-sophisticated techniques (AV, CV) often perform better than the relatively more-complex techniques (LHS, PS). A comprehensive bibliography is also provided

    A Multi-Mode Pattern Diverse Microstrip Patch Antenna Having a Constant Gain in the Elevation Plane

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    This study investigates a multi-mode pattern diverse microstrip patch antenna operating at 2.45 GHz. The study aims to have a flat top gain covering more than 900 in the elevation plane to provide equal service quality to everyone in the region of interest. In order to achieve such a crucial goal, the cavity model approach for the rectangular patches is employed. TM01 and TM02 modes are selected for the design since their corresponding radiation patterns are suitable for scanning a wide range. The superposition of boreside and conical (monopole-like) beams form a wide beam radiation pattern in elevation. Coupling between different modes is reduced by placing two radiators perpendicular to each other. In addition, the design aims to reduce both initial dimensions of the antenna by using fractalization, slotting, and perpendicular positioning techniques. These techniques reduce the original dimension of the design to less than its 60%. The simulation and experimental results reveal many similarities regarding the scattering parameters, radiation patterns, and gain. The scattering parameters, |S11| and |S22| at the operating frequency, are less than -10 dB, and the wide beam radiation pattern (more than 900) is obtained in the elevation plane

    Crystal structure and computational study of 3,4-dihydroxy-3-hydroxymethyl-9-methyl-6-methylidene-3a,4,5,6,6a,9,9a,9b-octahydroazuleno[4,5-b]furan-2,8(3H,7H)-dione

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    In the molecule of title compound, C15H20O6, also known as cynarinin A, the cyclopentane ring having twist conformation and a gamma-lactone ring assuming an envelope conformation are trans-and cis-fused, respectively, to a cycloheptane ring adopting a twist-chair conformation. In the crystal, O-H center dot center dot center dot O hydrogen bonds link neighbouring molecules, forming a three-dimensional network. Theoretical calculations of the molecular structure using the CNDO approximation and MOPAC PM3 geometry optimization are in satisfactory agreement with the results of the X-ray structure analysis
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