802 research outputs found

    Assessment of β-D-Glucosidase Activity from Two Typical Strains of the Lactic Acid Bacteria, Oenococcus oeni, in China

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    β-D-glucosidase (βG) is one of the most interesting glycosidases for the hydrolysis of glycoconjugatedprecursors to release active aromatic compounds in musts and wines. Oenococcus oeni strains SD-2a and31MBR are widely used in Chinese wines to reduce the acidity. In the present study, the βG activity of thetwo strains was localised and partially characterised using synthetic substrate. The activity occurred inwhole cells, sonication supernatants and debris, but not in the culture supernatants for both strains. Wholecells of strain SD-2a possessed greater βG activity, while strain 31MBR showed higher enzyme activity inthe sonication supernatants. Strain 31MBR exhibited higher total enzyme activity than strain SD-2a. Theoptimum temperatures for βG from the two strains were 40ºС at pH 3.5 and 50ºС at pH 5.0, respectively.Ethanol at low concentrations had a positive effect on βG activity in both strains, while a wine-like pH (3.5)decreased the enzyme activity to a great extent. Whole cells of strain SD-2a showed the highest activityamong all samples tested under wine-like conditions. Thus, strain SD-2a proved to have potential foraroma improvement in winemaking

    Passenger transmission and productiveness of transit lines with high loads

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    Deterministic transit capacity analysis applies to planning, design and operational management of urban transit systems. The Transit Capacity and Quality of Service Manual (1) and Vuchic (2, 3) enable transit performance to be quantified and assessed using transit capacity and productive capacity. This paper further defines important productive performance measures of an individual transit service and transit line. Transit work (p-km) captures the transit task performed over distance. Passenger transmission (p-km/h) captures the passenger task delivered by service at speed. Transit productiveness (p-km/h) captures transit work performed over time. These measures are useful to operators in understanding their services’ or systems’ capabilities and passenger quality of service. This paper accounts for variability in utilized demand by passengers along a line and high passenger load conditions where passenger pass-up delay occurs. A hypothetical case study of an individual bus service’s operation demonstrates the usefulness of passenger transmission in comparing existing and growth scenarios. A hypothetical case study of a bus line’s operation during a peak hour window demonstrates the theory’s usefulness in examining the contribution of individual services to line productive performance. Scenarios may be assessed using this theory to benchmark or compare lines and segments, conditions, or consider improvements

    Magnetization Plateaux in Bethe Ansatz Solvable Spin-S Ladders

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    We examine the properties of the Bethe Ansatz solvable two- and three-leg spin-SS ladders. These models include Heisenberg rung interactions of arbitrary strength and thus capture the physics of the spin-SS Heisenberg ladders for strong rung coupling. The discrete values derived for the magnetization plateaux are seen to fit with the general prediction based on the Lieb-Schultz- Mattis theorem. We examine the magnetic phase diagram of the spin-1 ladder in detail and find an extended magnetization plateau at the fractional value =1/2 = {1/2} in agreement with the experimental observation for the spin-1 ladder compound BIP-TENO.Comment: 11 pages, 1 figur

    Polarization of AGN in UV Spectral Range

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    We present the review of some new problems in cosmology and physics of stars in connection with future launching of WSO. We discuss three problems. UV observations of distant z > 6 quasars allow to obtain information on the soft < 1 KeV X-ray radiation of the accretion disk around a supermassive black hole because of its cosmological redshift. Really the region of X-ray radiation is insufficiently investigated because of high galactic absorption. In a result one will get important information on the reionization zone of the Universe. Astronomers from ESO revealed the effect of alignment of electric vectors of polarized QSOs. One of the probable mechanism of such alignment is the conversion of QSO radiation into low mass pseudoscalar particles (axions) in the extragalactic magnetic field. These boson like particles have been predicted by new SUSY particle physics theory. Since the probability of such conversion is increasing namely in UV spectral range one can expect the strong correlation between UV spectral energy distribution of QSO radiation and polarimetric data in the optical range. In the stellar physics one of the interesting problems is the origin of the X-ray sources with super Eddington luminosities. The results of UV observations of these X-ray sources will allow to find the origin of these sources as accreting intermediate mass black holes.Comment: 6 pages, 3 figure

    Stability and metastability of skyrmions in thin lamellae of Cu2OSeO3

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    We report small-angle x-ray scattering measurements of the skyrmion lattice in two 200-nm-thick Cu2OSeO3 lamellae aligned with the applied magnetic field parallel to the out of plane [110] or [100] crystallographic directions. Our measurements show that the equilibrium skyrmion phase in both samples is expanded significantly compared to bulk crystals, existing between approximately 30 and 50 K over a wide region of magnetic field. This skyrmion state is elliptically distorted at low fields for the [110] sample, and symmetric for the [100] sample, possibly due to crystalline anisotropy becoming more important at this sample thickness than it is in bulk samples. Furthermore, we find that a metastable skyrmion state can be observed at low temperature by field cooling through the equilibrium skyrmion pocket in both samples. In contrast to the behavior in bulk samples, the volume fraction of metastable skyrmions does not significantly depend on cooling rate. We show that a possible explanation for this is the change in the lowest temperature of the skyrmion state in this lamellae compared to bulk, without requiring different energetics of the skyrmion state

    Rms-flux relation in the optical fast variability data of BL Lacertae object S5 0716+714

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    The possibility that BL Lac S5 0716+714 exhibits a linear root mean square (rms)-flux relation in its IntraDay Variability (IDV) is analysed. The results may be used as an argument in the existing debate regarding the source of optical IDV in Active Galactic Nuclei. 63 time series in different optical bands were used. A linear rms-flux relation at a confidence level higher than 65% was recovered for less than 8% of the cases. We were able to check if the magnitude is log-normally distributed for eight timeseries and found, with a confidence > 95%, that this is not the case.Comment: Accepted by Astrophysics and Space Scienc

    Exact diagonalization of the generalized supersymmetric t-J model with boundaries

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    We study the generalized supersymmetric tJt-J model with boundaries in three different gradings: FFB, BFF and FBF. Starting from the trigonometric R-matrix, and in the framework of the graded quantum inverse scattering method (QISM), we solve the eigenvalue problems for the supersymmetric tJt-J model. A detailed calculations are presented to obtain the eigenvalues and Bethe ansatz equations of the supersymmetric tJt-J model with boundaries in three different backgrounds.Comment: Latex file, 32 page

    Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data

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    We investigate how the divergence-free property of magnetic fields can be exploited to resolve the azimuthal ambiguity present in solar vector magnetogram data, by using line-of-sight and horizontal heliographic derivative information as approximated from discrete measurements. Using synthetic data we test several methods that each make different assumptions about how the divergence-free property can be used to resolve the ambiguity. We find that the most robust algorithm involves the minimisation of the absolute value of the divergence summed over the entire field of view. Away from disk centre this method requires the sign and magnitude of the line-of-sight derivatives of all three components of the magnetic field vector.Comment: Solar Physics, in press, 20 pages, 11 figure

    Solutions of the reflection equation for face and vertex models associated with An(1),Bn(1),Cn(1),Dn(1)A_n^{(1)},B_n^{(1)},C_n^{(1)},D_n^{(1)} and An(2)A_n^{(2)}

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    We present new diagonal solutions of the reflection equation for elliptic solutions of the star-triangle relation. The models considered are related to the affine Lie algebras An(1),Bn(1),Cn(1),Dn(1)A_n^{(1)},B_n^{(1)},C_n^{(1)},D_n^{(1)} and An(2)A_n^{(2)}. We recover all known diagonal solutions associated with these algebras and find how these solutions are related in the elliptic regime. Furthermore, new solutions of the reflection equation follow for the associated vertex models in the trigonometric limit.Comment: 10 pages, LaTeX, no figure
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