10,032 research outputs found

    Characterization of the Torsional Piezoelectric-like Response of Tantalum Trisulfide Associated with Charge-Density-Wave Depinning

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    We have studied the frequency and voltage dependence of voltage-induced torsional strains in orthorhombic TaS3 [V. Ya. Pokrovskii, et al, Phys. Rev. Lett. 98, 206404 (2007)] by measuring the modulation of the resonant frequency of an RF cavity containing the sample. The strain has an onset voltage below the charge-density-wave (CDW) threshold voltages associated with changes in shear compliance and resistance, suggesting that the strain is associated with polarization of the CDW rather than CDW current. Measurements with square-wave voltages show that the strain is very sluggish, not even reaching its dc value at a frequency of 0.1 Hz, but the dynamics appear to be very sample dependent. By applying oscillating torque while biasing the sample with a dc current, we have also looked for strain induced voltage in the sample; none is observed at the low biases where the voltage-induced strains first occur, but an induced voltage is observed at higher biases, probably associated with strain-dependent CDW conductance.Comment: 11 pages, including 3 figures, to be published in Phys. Rev. B (Rapid Comm.

    A Consumer Test of Citrus Drinks made from Comminuted Whole Citrus Fruit

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    Consumer, Citrus, Whole Citrus Fruit, Citrus Fruit, Consumer Test, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

    A Consumer Test of Canned Seasoned Salad Tomatoes

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    Consumer, Canned Tomatoes, Salad Tomatoes, Seasoned Tomatoes, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

    Equivalences between spin models induced by defects

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    The spectrum of integrable spin chains are shown to be independent of the ordering of their spins. As an application we introduce defects (local spin inhomogeneities in homogenous chains) in two-boundary spin systems and, by changing their locations, we show the spectral equivalence of different boundary conditions. In particular we relate certain nondiagonal boundary conditions to diagonal ones.Comment: 14 pages, 16 figures, LaTeX, Extended versio

    Structure of the two-boundary XXZ model with non-diagonal boundary terms

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    We study the integrable XXZ model with general non-diagonal boundary terms at both ends. The Hamiltonian is considered in terms of a two boundary extension of the Temperley-Lieb algebra. We use a basis that diagonalizes a conserved charge in the one-boundary case. The action of the second boundary generator on this space is computed. For the L-site chain and generic values of the parameters we have an irreducible space of dimension 2^L. However at certain critical points there exists a smaller irreducible subspace that is invariant under the action of all the bulk and boundary generators. These are precisely the points at which Bethe Ansatz equations have been formulated. We compute the dimension of the invariant subspace at each critical point and show that it agrees with the splitting of eigenvalues, found numerically, between the two Bethe Ansatz equations.Comment: 9 pages Latex. Minor correction

    Generalized T-Q relations and the open spin-s XXZ chain with nondiagonal boundary terms

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    We consider the open spin-s XXZ quantum spin chain with nondiagonal boundary terms. By exploiting certain functional relations at roots of unity, we derive a generalized form of T-Q relation involving more than one independent Q(u), which we use to propose the Bethe-ansatz-type expressions for the eigenvalues of the transfer matrix. At most two of the boundary parameters are set to be arbitrary and the bulk anisotropy parameter has values \eta = i\pi/2, i\pi/4,... We also provide numerical evidence for the completeness of the Bethe-ansatz-type solutions derived, using s = 1 case as an example.Comment: 23 pages. arXiv admin note: substantial text overlap with arXiv:0901.3558; v2: published versio

    Oxidative stress in relation to diet and physical activity among premenopausal women

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    Abstract Higher levels of oxidative stress, as measured by F 2 -isoprostanes, have been associated with chronic diseases such as CVD and some cancers. Improvements in diet and physical activity may help reduce oxidative stress; however, previous studies regarding associations between lifestyle factors and F 2 -isoprostane concentrations have been inconsistent. The aim of this cross-sectional study was to investigate whether physical activity and intakes of fruits/vegetables, antioxidant nutrients, dietary fat subgroups and alcohol are associated with concentrations of F 2 -isoprostane and the major F 2 -isoprostane metabolite. Urinary F 2 -isoprostane and its metabolite were measured in urine samples collected at enrolment from 912 premenopausal women (aged 35–54 years) participating in the Sister Study. Physical activity, alcohol consumption and dietary intakes were self-reported via questionnaires. With adjustment for potential confounders, the geometric means of F 2 -isoprostane and its metabolite were calculated according to quartiles of dietary intakes, alcohol consumption and physical activity, and linear regression models were used to evaluate trends. Significant inverse associations were found between F 2 -isoprostane and/or its metabolite and physical activity, vegetables, fruits, vitamin C, α -carotene, vitamin E, β -carotene, vitamin A, Se, lutein+zeaxanthin and long-chain n -3 fatty acids. Although trans fats were positively associated with both F 2 -isoprostane and its metabolite, other dietary fat subgroups including SFA, n -6 fatty acids, n -3 fatty acids, MUFA, PUFA, short-chain n -3 fatty acids, long-chain n -3 fatty acids and total fat were not associated with either F 2 -isoprostane or its metabolite. Our findings suggest that lower intake of antioxidant nutrients and higher intake of trans fats may be associated with greater oxidative stress among premenopausal women

    Microdosing psychedelics: More questions than answers? An overview and suggestions for future research

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    Background: In the past few years, the issue of \u2018microdosing\u2019 psychedelics has been openly discussed in the public arena where claims have been made about their positive effect on mood state and cognitive processes such as concentration. However, there are very few scientific studies that have specifically addressed this issue, and there is no agreed scientific consensus on what microdosing is. Aim: This critique paper is designed to address questions that need to be answered by future scientific studies and to offer guidelines for these studies. Approach: Owing to its proximity for a possible approval in clinical use and short-lasting pharmacokinetics, our focus is predominantly on psilocybin. Psilocybin is allegedly, next to lysergic acid diethylamide (LSD), one of the two most frequently used psychedelics to microdose. Where relevant and available, data for other psychedelic drugs are also mentioned. Conclusion: It is concluded that while most anecdotal reports focus on the positive experiences with microdosing, future research should also focus on potential risks of (multiple) administrations of a psychedelic in low doses. To that end, (pre)clinical studies including biological (e.g. heart rate, receptor turnover and occupancy) as well as cognitive (e.g. memory, attention) parameters have to be conducted and will shed light on the potential negative consequences microdosing could have
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