Comment on "Secure direct communication with a quantum one-time pad"

In the paper [Phys. Rev. A \textbf{69}, 052319 (2004)], a quantum direct communication protocol is proposed which is claimed to be unconditionally secure even for the case of a noisy channel. We show that this is not the case by giving an undetectable attack scheme

A novel method for subjective picture quality assessment and further studies of HDTV formats

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ IEEE 2008.This paper proposes a novel method for the assessment of picture quality, called triple stimulus continuous evaluation scale (TSCES), to allow the direct comparison of different HDTV formats. The method uses an upper picture quality anchor and a lower picture quality anchor with defined impairments. The HDTV format under test is evaluated in a subjective comparison with the upper and lower anchors. The method utilizes three displays in a particular vertical arrangement. In an initial series of tests with the novel method, the HDTV formats 1080p/50,1080i/25, and 720p/50 were compared at various bit-rates and with seven different content types on three identical 1920 times 1080 pixel displays. It was found that the new method provided stable and consistent results. The method was tested with 1080p/50,1080i/25, and 720p/50 HDTV images that had been coded with H.264/AVC High profile. The result of the assessment was that the progressive HDTV formats found higher appreciation by the assessors than the interlaced HDTV format. A system chain proposal is given for future media production and delivery to take advantage of this outcome. Recommendations for future research conclude the paper

The state space of short-range Ising spin glasses: the density of states

The state space of finite square and cubic Ising spin glass models is analysed in terms of the global and the local density of states. Systems with uniform and gaussian probability distribution of interactions are compared. Different measures for the local state density are presented and discussed. In particular the question whether the local density of states grows exponentially or not is considered. The direct comparison of global and local densities leads to consequences for the structure of the state space.Comment: 18 pages (including 6 figures); submitted to Z.f.Physik

Studies on the bit rate requirements for a HDTV format with 1920 timestimes 1080 pixel resolution, progressive scanning at 50 Hz frame rate targeting large flat panel displays

This paper considers the potential for an HDTV delivery format with 1920 times 1080 pixels progressive scanning and 50 frames per second in broadcast applications. The paper discusses the difficulties in characterizing the display to be assumed for reception. It elaborates on the required bit rate of the 1080p/50 format when critical content is coded in MPEG-4 H.264 AVC Part 10 and subjectively viewed on a large, flat panel display with 1920 times 1080 pixel resolution. The paper describes the initial subjective quality evaluations that have been made in these conditions. The results of these initial tests suggest that the required bit-rate for a 1080p/50 HDTV signal in emission could be kept equal or lower than that of 2nd generation HDTV formats, to achieve equal or better image qualit

Resonance structure in low-energy electron scattering from OCS

Energy-dependent absolute angle-differential cross sections (θ = 135°) for elastic and vibrationally inelastic electron scattering from OCS molecules have been investigated at high resolution (13 meV). The elastic cross section, reported over the range E= 0.06–20 eV, exhibits a deep Ramsauer–Townsend minimum near 0.55 eV and the π*(1.2 eV) and σ*(3.8 eV) resonances known from earlier experimental and theoretical work. The excitation functions for vibrational excitation (VE) of the fundamental CS stretch (1 0 0), the CO stretch (0 0 1) as well as for the fundamental and harmonics of the bending (0 n 0) mode are reported from threshold up to E = 8 eV. VE is mediated—in part in a mode-selective way—by threshold peaks and the higher lying resonances. The selectivity in the threshold region can be rationalized in terms of symmetry arguments where the ²Σ virtual state excites preferentially the σ vibrational states with even quanta of bending vibration over the π vibrational states with odd quanta of bending vibration. The σ*CS resonance is essentially inactive in VE of the CO stretch and the bending mode

Enhancement of perfluorooctanoate and perfluorooctanesulfonate activity at acoustic cavitation bubble interfaces

Acoustic cavitation driven by ultrasonic irradiation decomposes and mineralizes the recalcitrant perfluorinated surfactants perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA). Pyrolytic cleavage of the ionic headgroup is the rate-determining step. In this study, we examine the sonochemical adsorption of PFOX, where X = S for PFOS and A for PFOA, by determining kinetic order and absolute rates over an initial PFOX concentration range of 20 nM to 200 μM. Sonochemical PFOX kinetics transition from pseudo-first-order at low initial concentrations, [PFOX]_i 40 μM, as the bubble interface sites are saturated. At PFOX concentrations below 100 μM, concentration-dependent rates were modeled with Langmuir−Hinshelwood (LH) kinetics. Empirically determined rate maximums, V_(Max)^(−PFOA) = 2230 ± 560 nM min^−1 and V_(Max)^(−PFOS) = 230 ± 60 nM min^−1, were used in the LH model, and sonochemical surface activities were estimated to be K_(Sono)^(PFOS) = 120000 M^−1 and K_(Sono)^(PFOA) = 28500 M^−1, 60 and 80 times greater than equilibrium surface activities, K_(Eq)^(PFOS) and K_(Eq)^(PFOA). These results suggest enhanced sonochemical degradation rates for PFOX when the bubble interface is undersaturated. The present results are compared to previously reported sonochemical kinetics of nonvolatile surfactants

Einstein-Born-Infeld on Taub-NUT Spacetime in 2k+2 Dimensions

We wish to construct solutions of Taub-NUT spacetime in Einstein-Born-Infeld gravity in even dimensions. Since Born-Infeld theory is a nonlinear electrodynamics theory, in leads to nonlinear differential equations. However a proper analytical solution was not obtain, we try to solve it numerically (by the Runge-Kotta method) with initial conditions coinciding with those of our previous work in Einstein-Maxwell gravity. We solve equations for 4, 6 and 8 dimensions and do data fitting by the least-squares method. For N=l=b=1, the metric turns to the NUT solution only in 8 dimensions, but in 4 and 6 dimensions the spacetime does not have any Nut solution.Comment: 8 pages, 5 figure