Relaxation of Chemical Reactions to Stationary States in the Chemical Affinities Space

Using the mass balance equations for chemical reactions, we show how the system relaxes towards a steady state in and out of the Onsager region. In the chemical affinities space, after fast transients, the relaxation process is a straight line when operating in the Onsager region, while out of this regime, the evolution of the system is such that the projections of the evolution equations for the forces and the shortest path on the flows coincide. For spatially-extended systems, similar results are valid for the evolution of the thermodynamic mode (i.e., the mode with wave-number k = 0). These results allow us to obtain the expression for the affine connection of the space covered by the thermodynamic forces, close to the steady states. Through the affine connection, the nonlinear closure equations are derived.Comment: 23 pages

A large-N approximated field theory for multipartite entanglement

We study the characterization of multipartite entanglement for the random states of an $n$-qbit system. Unable to solve the problem exactly we generalize it, changing complex numbers into real vectors with $N_c$ components (the original problem is recovered for $N_c=2$). Studying the leading diagrams in the large-$N_c$ approximation, we unearth the presence of a phase transition and, in an explicit example, show that the so-called entanglement frustration disappears in the large-$N_c$ limit.Comment: 12 pages, 15 figure

Preeminent role of the Van Hove singularity in the strong-coupling analysis of scanning tunneling spectroscopy for two-dimensional cuprates

In two dimensions the non-interacting density of states displays a Van Hove singularity (VHS) which introduces an intrinsic electron-hole asymmetry, absent in three dimensions. We show that due to this VHS the strong-coupling analysis of tunneling spectra in high-$T_c$ superconductors must be reconsidered. Based on a microscopic model which reproduces the experimental data with great accuracy, we elucidate the peculiar role played by the VHS in shaping the tunneling spectra, and show that more conventional analyses of strong-coupling effects can lead to severe errors.Comment: 5 pages, 4 figure

Two new intermediate polars with a soft X-ray component

Aims. We analyze the first X-ray observations with XMM-Newton of 1RXS J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as intermediate polars. Methods. For both objects, we performed a timing analysis of the X-ray and UV/optical light curves to detect the white dwarf spin pulsations and study their energy dependence. For 1RXS 180340.0+401214 we also analyzed optical spectroscopic data to determine the orbital period. X-ray spectra were analyzed in the 0.2–10.0 keV range to characterize the emission properties of both sources. Results. We find that the X-ray light curves of both systems are energy dependent and are dominated, below 3–5 keV, by strong pulsations at the white dwarf rotational periods (480 s for 1RXS J070407.9+262501 and 1520.5 s for 1RXS 180340.0+401214). In 1RXS 180340.0+401214 we also detect an X-ray beat variability at 1697 s which, together with our new optical spectroscopy, favours an orbital period of 4.4 h that is longer than previously estimated. Both systems show complex spectra with a hard (temperature up to 40 keV) optically thin and a soft (kT ∼ 85–100 eV) optically thick components heavily absorbed by material partially covering the X-ray sources. Conclusions. Our observations confirm the two systems as intermediate polars and also add them as new members of the growing group of “soft” systems which show the presence of a soft X-ray blackbody component. Differences in the temperatures of the blackbodies are qualitatively explained in terms of reprocessing over different sizes of the white dwarf spot. We suggest that systems showing cooler soft X-ray blackbody components also possess white dwarfs irradiated by cyclotron radiation

From rods to helices: evidence of a screw-like nematic phase

Evidence of a special chiral nematic phase is provided using numerical simulation and Onsager theory for systems of hard helical particles. This phase appears at the high density end of the nematic phase, when helices are well aligned, and is characterized by the C$_2$ symmetry axes of the helices spiraling around the nematic director with periodicity equal to the particle pitch. This coupling between translational and rotational degrees of freedom allows a more efficient packing and hence an increase of translational entropy. Suitable order parameters and correlation functions are introduced to identify this screw-like phase, whose main features are then studied as a function of radius and pitch of the helical particles. Our study highlights the physical mechanism underlying a similar ordering observed in colloidal helical flagella [E. Barry et al. \textit{Phys. Rev. Lett.} \textbf{96}, 018305 (2006)] and raises the question of whether it could be observed in other helical particle systems, such as DNA, at sufficiently high densities.Comment: List of authors correcte

Efficacy of vitamin E in the conservative treatment of Peyronie's disease: legend or reality? A controlled study of 70 cases

The medical treatment is indicated in the development stage of Peyronie’s disease (PD) for at least 1 year after diagnosis and whenever in case of penile pain. This research was conducted to demonstrate the possible effectiveness of vitamin E in PD treatment, whereas in the scientific literature this topic is much discussed. A total of 70 patients (age:26–69 years, mean: 54.1 ± 9.71) diagnosed with PD were enrolled in a conservative treatment. In addition to medical histories and physical examinations all patients underwent the following tests: International Index of Erectile Function (IIEF) questionnaire, penile ultrasound and photographic documentation, pain evaluation by a conventional 10-point pain scale Visual analogue pain scale (VAS). All 70 patients were divided into two different treatment groups: A and B, with different combinations of drugs: A = vitamin E + verapamil (injection + iontophoresis) + blueberries + propolis + topical diclofenac; B = verapamil (injection + iontophoresis) + blueberries + propolis + topical diclofenac. All patients were treated for 6 months after which they underwent the same follow-up tests as performed prior to the treatment. Intergroup analysis revealed statistically significant differences: in the vitamin E group the effective plaque size reduction was 50.2% whereas in the control group the reduction was 35.8% (p = 0.027). In group A the improvement of curvature occurred in 96.6% of the cases whereas in the control group B this occurred in 48.4% (p = 0.0001), moreover, the mean curvature decrease was respectively 12.25° and 6.73° (p = 0.01). IIEF score was significantly improved in group A patients with comorbidities and erectile dysfunction (p = 0.025). Increase in plaque size occurred only in the control group (17.1%) (p = 0.032). We can affirm that vitamin E can help to prevent the progression of PD. This study strongly supports the recommendation that the best approach for treating PD is multimodal therapy

Equilibrium and off-equilibrium simulations of the 4d Gaussian spin glass

In this paper we study the on and off-equilibrium properties of the four dimensional Gaussian spin glass. In the static case we determine with more precision that in previous simulations both the critical temperature as well as the critical exponents. In the off-equilibrium case we settle the general form of the autocorrelation function, and show that is possible to obtain dynamically, for the first time, a value for the order parameter.Comment: 16 pages and 13 figures, uses epsfig.sty and rotate.sty. Some minor grammatical changes. Also available at http://chimera.roma1.infn.it/index_papers_complex.htm

The Glassy Potts Model

We introduce a Potts model with quenched, frustrated disorder, that enjoys of a gauge symmetry that forbids spontaneous magnetization, and allows the glassy phase to extend from $T_c$ down to T=0. We study numerical the 4 dimensional model with $q=4$ states. We show the existence of a glassy phase, and we characterize it by studying the probability distributions of an order parameter, the binder cumulant and the divergence of the overlap susceptibility. We show that the dynamical behavior of the system is characterized by aging.Comment: 4 pages including 4 (color) ps figures (all on page 4

Uses and gratifications of multiscreen news consumption among Spanish youth

This paper aims to describe how Spanish youth use multiscreen in a news search context, and what are the gratifications they obtain through this multichannel model. A survey was responded by a panel of 441 individuals representative of the national population in an 18-35 age range. Five gratifications were found: the desire to obtain “information in real time,” “social interaction,” “comprehension,” “leisure,” and “habit.” The desire to obtain “information in real time” predicts multiscreen use behavior when searching for news. Moreover, three factors are relevant when predicting the duration of multiscreen use: “information in real time,” “social interaction,” and “leisure.”Este artículo tiene como objetivo describir cómo los jóvenes españoles utilizan la multipantalla en un contexto de búsqueda de noticias y cuáles son las gratificaciones que obtienen a través de este modelo multicanal. Se realizó una encuesta que fue respondida por un panel de 441 individuos representativos de la población nacional en un rango de edad de 18 a 35 años. Se encontraron cinco gratificaciones: el deseo de obtener “información en tiempo real”, “interacción social”, “comprensión”, “ocio” y “hábito”. El deseo de obtener “información en tiempo real” predice el comportamiento de uso de múltiples pantallas en la búsqueda de noticias. Además, tres factores son relevantes al predecir la duración del uso de múltiples pantallas: “información en tiempo real”, “interacción social” y “ocio”