169 research outputs found

    Phase statistics of the WMAP 7 year data

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    We performed a comprehensive statistical analysis using complex phases of the a_lm coefficients computed from the most recent data of the Wilkinson Microwave Anisotropy Probe (WMAP). Our aim was to confirm or constrain the presence of non-Gaussianities in the data. We found phase correlations - that suggest non-Gaussianity - at high-l in a_lm coefficients by applying various statistical tests. Most of all, we detected a non-Gaussian signal reaching a significance of 4.7 sigma using random walk statistics and simulations. However, our conclusion is that the non-Gaussian behavior is due to contamination from galactic foregrounds that show up in small scales only. When masked out the contaminated regions, we found no significant non-Gaussianity. Furthermore, we constrained the f_NL parameter using CMB simulations that mimic primordial non-Gaussianity. Our estimate is f_NL=40 +/- 200, in agreement with previous measurements and inflationary expectations.Comment: 4 pages, 4 figures, Accepted for Publication in A

    Synthesis of Shape-Tailored WO3 Micro-/Nanocrystals and the Photocatalytic Activity of WO3/TiO2 Composites

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    A traditional semiconductor (WO3) was synthesized from different precursors via hydrothermal crystallization targeting the achievement of three different crystal shapes (nanoplates, nanorods and nanostars). The obtained WO3 microcrystals were analyzed by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). These methods contributed to the detailed analysis of the crystal morphology and structural features. The synthesized bare WO3 photocatalysts were totally inactive, while the P25/WO3 composites were efficient under UV light radiation. Furthermore, the maximum achieved activity was even higher than the bare P25's photocatalytic performance. A correlation was established between the shape of the WO3 crystallites and the observed photocatalytic activity registered during the degradation of different substrates by using P25/WO3 composites

    Synthesis of Shape-Tailored WO3 Micro-/Nanocrystals and the Photocatalytic Activity of WO3/TiO2 Composites

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    A traditional semiconductor (WO3) was synthesized from different precursors via hydrothermal crystallization targeting the achievement of three different crystal shapes (nanoplates, nanorods and nanostars). The obtained WO3 microcrystals were analyzed by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). These methods contributed to the detailed analysis of the crystal morphology and structural features. The synthesized bare WO3 photocatalysts were totally inactive, while the P25/WO3 composites were efficient under UV light radiation. Furthermore, the maximum achieved activity was even higher than the bare P25's photocatalytic performance. A correlation was established between the shape of the WO3 crystallites and the observed photocatalytic activity registered during the degradation of different substrates by using P25/WO3 composites

    Szerkezeti topolĂłgia = Structural topology

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    Numerikus megoldásokat állítottunk elő a körpárok és körhármasok gömbön való legsűrűbb elhelyezésének problémájára, és szimmetria alapú vizsgálatokat végeztünk a gömbi körelhelyezés gráfjának Danzer-féle merevségére vonatkozóan. Egy általunk bevezetett gömbölyűségi kritérium alapján optimális, gömböt közelítő poliédereket konstruáltunk. A szakrális épületeken előforduló csillagpoliéderekre alakmeghatározást és számítógépes rekonstrukciót hajtottunk végre. Konvex testekre vonatkozóan több tételt bizonyítottunk. Meghatároztuk a gömbi és térbeli trivalens szálhálózatok megfeszíthetőségének feltételeit. Gömbi koordinátákban írtuk fel a gömbfelszínre illeszkedő csuklós rúdszerkezetek egyensúlyi és kompatibilitási egyenleteit, és állítottuk elő a szerkezet potenciálfüggvényét. Bebizonyítottuk, hogy egy túlhatározott, háromszorosan szimmetrikus Bricard-mechanizmus esetében bizonyos paraméter értékeknél előfordulhat a kompatibilitási út elágazása. A katasztrófaelméletet kompatibilitási utak elágazásának vizsgálatára alkalmaztuk. Az itt előforduló kettőscsúcs-katasztrófával kapcsolatban egy olyan modellcsaládot elemeztünk, amely a kettőscsúcs-katasztrófa négy alosztályán is keresztülhalad. | Numerical solutions are established to the problem of the densest packing of pairs and triplets of circles on a sphere, and symmetry extended analysis of the Danzerian rigidity of the packing graphs is executed. On the basis of a sphericity criterion introduced by us, polyhedra approximating the sphere are constructed. Shape determination and computer aided reconstruction is done for star polyhedra occurring on sacred buildings. A number of theorems are proved for convex bodies. Criteria of stressability of spherical and spatial trivalent fibre nets are determined. Equilibrium and compatibility equations as well as potential function of bar-and-joint assemblies lying on the surface of a sphere are written with spherical co-ordinates. It is proved that, for certain parameter values, there exists bifurcation of the compatibility path of an overconstrained, threefold symmetric Bricard linkage. Catastrophe theory is applied for investigation of bifurcation of compatibility paths. Concerning double cusp catastrophe, a family of models is analysed, which goes through four subclasses of the double cusp catastrophe

    ASSESSING THE POSSIBLE INTERACTION BETWEEN CARDUUS MARIANUS AND DIETARY DEOXYNIVALENOL ON CAECAL MICROBIOTA AND FERMENTATION OF GROWING RABBITS

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    Contamination of feed with mycotoxins is a common problem encountered in animal farming. Mycotoxin exposure can affect adversely the health of animals. In rabbits caecal fermentation is an essential digestive process being indication of physiological alterations. Deoxynivalenol (DON) is one of the most frequent contaminants of grains which affect the growth of monogastric animals. Data about dietary DON and its effect in rabbits are scarce. Medicinal plants are often used as feed additives to enhance the performance of the animals. Carduus marianus (milk thistle) is known for its hepatoprotective and antioxidant effects (among others) but no data are available about the effect on rabbit caecum. Considering the aforementioned, the aim of this study was to assess the possible interactive effect of Carduus marianus and DON on the caecum of growing rabbits. 75 Pannon White rabbits were reared for six weeks from 35 (after weaning) till 77 days of age. Rabbits received the following diets: control (C), control with DON (CT), control supplemented with C. marianus in 0,5% (H1), control supplemented with C. marianus in 0,5% and DON (H1T), control supplemented with C. marianus in 1% (H2) and control supplemented with C. marianus in 1% and DON (H2T). On slaughter, caecum was collected for the analysis of total volatile fatty acids (VFA) and the microbiota of the caecum, pH of the caecum was also recorded. There was no significant difference in total VFA concentration or individual VFA. Number of aerobic bacteria significantly differed among toxin and non-toxin groups. DON affected adversely the number of aerobic bacteria. An interactive effect of DON and Carduus marianus on E.coli number was observed. There was no effect on total or individual VFA amounts
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