2,416 research outputs found

    Exact quantum states of a general time-dependent quadratic system from classical action

    Full text link
    A generalization of driven harmonic oscillator with time-dependent mass and frequency, by adding total time-derivative terms to the Lagrangian, is considered. The generalization which gives a general quadratic Hamiltonian system does not change the classical equation of motion. Based on the observation by Feynman and Hibbs, the propagators (kernels) of the systems are calculated from the classical action, in terms of solutions of the classical equation of motion: two homogeneous and one particular solutions. The kernels are then used to find wave functions which satisfy the Schr\"{o}dinger equation. One of the wave functions is shown to be that of a Gaussian pure state. In every case considered, we prove that the kernel does not depend on the way of choosing the classical solutions, while the wave functions depend on the choice. The generalization which gives a rather complicated quadratic Hamiltonian is simply interpreted as acting an unitary transformation to the driven harmonic oscillator system in the Hamiltonian formulation.Comment: Submitted to Phys. Rev.

    Spectral density analysis of time correlation functions in lattice QCD using the maximum entropy method

    Get PDF
    We study various aspects of extracting spectral information from time correlation functions of lattice QCD by means of Bayesian inference with an entropic prior, the maximum entropy method (MEM). Correlator functions of a heavy-light meson-meson system serve as a repository for lattice data with diverse statistical quality. Attention is given to spectral mass density functions, inferred from the data, and their dependence on the parameters of the MEM. We propose to employ simulated annealing, or cooling, to solve the Bayesian inference problem, and discuss practical issues of the approach.Comment: 11 pages, 30 figure files (eps), some references added and updated, requires REVTeX 4.0 and prerequisites (AMS-LaTeX 2.0, graphicx, dcolumn, bm) see http://publish.aps.org/revtex4

    The Liquid-Gas Phase Transitions in a Multicomponent Nuclear System with Coulomb and Surface Effects

    Get PDF
    The liquid-gas phase transition is studied in a multi-component nuclear system using a local Skyrme interaction with Coulomb and surface effects. Some features are qualitatively the same as the results of Muller and Serot which uses relativistic mean field without Coulomb and surface effects. Surface tension brings the coexistance binodal surface to lower pressure. The Coulomb interaction makes the binodal surface smaller and cause another pair of binodal points at low pressure and large proton fraction with less protons in liquid phase and more protons in gas phase.Comment: 20 pages including 7 postscript figure

    Sources of dietary iodines bread, cows' milk, and infant formula in the Boston area

    No full text
    Dietary iodine is essential for thyroid hormone production. Although U.S. dietary iodine is generally adequate, some groups, especially women of childbearing age, are at risk for mild iodine deficiency. Children's average urinary iodine is higher than that of adults. U.S. dietary iodine sources have not been assessed recently. A survey of iodine content in 20 brands of bread, 18 brands of cows' milk, and eight infant formulae was performed between 2001 and 2002. Three bread varieties contained more than 300 μg iodine per slice. Iodine content in other brands was far lower (mean ± SD, 10.1 ± 13.2 μg iodine/ slice). All cows' milk samples had at least 88 μg iodine/250 ml, ranging from 88-168 μg (116.0 ± 22.1 μg/250 ml). Infant formulae values ranged from 16.2 to 56.8 μg iodine/5 oz (23.5 ± 13.78 μg/5 oz). The public should be aware of the need for adequate dietary iodine intake and should be aware that ingredient lists do not reflect the iodine content of foods

    Dose-Response Relationships Following Oral Administration of DuP 753 to Normal Humans

    Get PDF
    We assessed the inhibitory effect of DuP 753, an orally active angiotensin II receptor antagonist, on the pressor action of exogenous angiotensin I and II in healthy volunteers. In a single dose study, doses of 2.5, 5, 10, 20, and 40 mg of DuP 753 or placebo were tested serially at one week intervals. In the multiple dose study, the administration of placebo or DuP 753 (5, 10, 20, or 40 mg, per os once daily) for eight consecutive days was evaluated. The blood pressure response to angiotensin I and II was inhibited in a dose-dependent fashion with a blocking effect still present 24 h post drug. DuP 753 also induced a dose-dependent compensatory rise in plasma renin. This new compound was well tolerated by these normal volunteers. Thus, DuP 753 appears to be a well tolerated, orally active, potent and long-lasting antagonist of angiotensin II in humans. Am J Hypertens 1991;4:350S-354

    Coping with and self-management of chronic painful chemotherapy-induced peripheral neuropathy:A qualitative study among cancer survivors

    Get PDF
    PurposePatients with chronic painful chemotherapy-induced peripheral neuropathy (CIPN) may experience a negative impact of CIPN on daily life. They can use various coping (i.e., dealing with symptoms and resulting impairments in general) and self-management (i.e., practical actions to reduce symptoms) strategies to live with their limitations. This paper aimed to examine experienced helpful coping and self-management strategies of patients with chronic painful CIPN.MethodsSemi-structured interviews were conducted with twelve patients with chronic painful CIPN. We applied a hybrid deductive-inductive coding approach. ATLAS.ti was used for coding.ResultsGenerated from the data were two themes and nine codes for coping and four themes and 31 codes for self-management strategies. Coping of patients often included active strategies like planning, seeking social support, and acceptance. Additionally, patients often used passive strategies such as focusing on and venting emotions and suppressing competing activities. The most common self-management strategies were mostly passive (i.e., medication, deliberate choice of shoes, resting, sitting, and consulting healthcare professionals) but also active (i.e., exercising) strategies.ConclusionPatients exhibit a great variety of coping and self-management strategies that they perceive as helpful to deal with chronic painful CIPN. However, research has shown that certain strategies are not that helpful or even come with aversive effects. More research into the effectiveness and implementation of psychosocial interventions is needed since it may help patients adopting helping strategies. In addition, healthcare professionals need to refer patients with CIPN in a timely manner to physical therapists, occupational therapists, or rehabilitation teams to reduce or prevent (further) impairments.Implications for Cancer SurvivorsPatients can consult one of their healthcare providers in case of problems in dealing with their symptoms, to get proper guidance and possible referral.<br/

    X-ray microdiffraction studies of an integrated laser-modulator system

    Full text link
    The authors report the use of a spatially resolved x-ray microdiffraction technique for the structural study of an integrated laser-modulator system. The monochromatic (11 keV) x-ray beam microfocused to less than 1 {micro}m in the vertical direction was obtained using a phase zone plate. The photon flux at the focal spot exceeded 3 {times} 10{sup 10} photons/s/0.01% bw/{micro}m{sup 2}. The intense flux density and high spatial resolution of the focused beam was used to study the structure of a laser-modulator system, which is a 1-{micro}m-wide and 1-mm-long multi-quantum well structure on an InP substrate. The superlattice d-spacing and the strain field in the direction normal to the diffracting planes were mapped as a function of position along the length of the device

    STT-MRAM for real-time embedded systems: performance and WCET implications

    Get PDF
    STT-MRAM is an emerging non-volatile memory quickly approaching DRAM in terms of capacity, frequency and device size. Intensified efforts in STT-MRAM research by the memory manufacturers may indicate a revolution with STT-MRAM memory technology is imminent, and therefore it is essential to perform system level research to explore use-cases and identify computing domains that could benefit from this technology. Special STT-MRAM features such as intrinsic radiation hardness, non-volatility, zero stand-by power and capability to function in extreme temperatures makes it particularly suitable for aerospace, avionics and automotive applications. Such applications often have real-time requirements --- that is, certain tasks must complete within a strict deadline. Analyzing whether this deadline is met requires Worst Case Execution Time (WCET) Analysis, which is a fundamental part of evaluating any real-time system. In this study, we investigate the feasibility of using STT-MRAM in real-time embedded systems by analyzing average system performance impact and WCET implications.This work was supported by BSC, Spanish Government through Programa Severo Ochoa (SEV-2015-0493), by the Spanish Ministry of Science and Technology through TIN2015-65316-P project and by the Generalitat de Catalunya (contracts 2014-SGR-1051 and 2014-SGR-1272). This work has also received funding from the European Union’s Horizon 2020 research and innovation programme under ExaNoDe project (grant agreement No 671578). Jaume Abella was partially supported by the Ministry of Economy and Competitive-ness under Ramon y Cajal postdoctoral fellowship RYC-2013-14717.Peer ReviewedPostprint (author's final draft

    The application of Raman and anti-stokes Raman spectroscopy for in-situ monitoring of structural changes in laser irradiated titanium dioxide materials.

    Get PDF
    The use of Raman and anti-stokes Raman spectroscopy to investigate the effect of exposure to high power laser radiation on the crystalline phases of TiO 2 has been investigated. Measurement of the changes, over several time integrals, in the Raman and anti-stokes Raman of TiO 2 spectra with exposure to laser radiation is reported. Raman and anti-stokes Raman provide detail on both the structure and the kinetic process of changes in crystalline phases in the titania material. The effect of laser exposure resulted in the generation of increasing amounts of the rutile crystalline phase from the anatase crystalline phase during exposure. The Raman spectra displayed bands at 144 cm -1 (A1g), 197 cm -1 (Eg), 398 cm -1 (B1g), 515 cm -1 (A1g), and 640 cm -1 (Eg) assigned to anatase which were replaced by bands at 143 cm -1 (B1g), 235 cm -1 (2 phonon process), 448 cm -1 (Eg) and 612 cm -1 (A1g) which were assigned to rutile. This indicated that laser irradiation of TiO 2 changes the crystalline phase from anatase to rutile. Raman and anti-stokes Raman are highly sensitive to the crystalline forms of TiO 2 and allow characterisation of the effect of laser irradiation upon TiO 2 . This technique would also be applicable as an in situ method for monitoring changes during the laser irradiation process

    Infrared Behavior of the Gluon Propagator on a Large Volume Lattice

    Get PDF
    The first calculation of the gluon propagator using an order a^2 improved action with the corresponding order a^2 improved Landau gauge fixing condition is presented. The gluon propagator obtained from the improved action and improved Landau gauge condition is compared with earlier unimproved results on similar physical lattice volumes of 3.2^3 \times 6.4 fm^4. We find agreement between the improved propagator calculated on a coarse lattice with lattice spacing a = 0.35 fm and the unimproved propagator calculated on a fine lattice with spacing a = 0.10 fm. This motivates us to calculate the gluon propagator on a coarse large-volume lattice 5.6^3 \times 11.2 fm^4. The infrared behavior of previous studies is confirmed in this work. The gluon propagator is enhanced at intermediate momenta and suppressed at infrared momenta. Therefore the observed infrared suppression of the Landau gauge gluon propagator is not a finite volume effect.Comment: 8 pages, 4 figures, minor typos corrected and repsonse to referees comment
    • …
    corecore