Non-Gaussian Fluctuations in Biased Resistor Networks: Size Effects versus Universal Behavior

We study the distribution of the resistance fluctuations of biased resistor networks in nonequilibrium steady states. The stationary conditions arise from the competition between two stochastic and biased processes of breaking and recovery of the elementary resistors. The fluctuations of the network resistance are calculated by Monte Carlo simulations which are performed for different values of the applied current, for networks of different size and shape and by considering different levels of intrinsic disorder. The distribution of the resistance fluctuations generally exhibits relevant deviations from Gaussianity, in particular when the current approaches the threshold of electrical breakdown. For two-dimensional systems we have shown that this non-Gaussianity is in general related to finite size effects, thus it vanishes in the thermodynamic limit, with the remarkable exception of highly disordered networks. For these systems, close to the critical point of the conductor-insulator transition, non-Gaussianity persists in the large size limit and it is well described by the universal Bramwell-Holdsworth-Pinton distribution. In particular, here we analyze the role of the shape of the network on the distribution of the resistance fluctuations. Precisely, we consider quasi-one-dimensional networks elongated along the direction of the applied current or trasversal to it. A significant anisotropy is found for the properties of the distribution. These results apply to conducting thin films or wires with granular structure stressed by high current densities.Comment: 8 pages, 4 figures. Invited talk at the 18-th International Conference on Noise and Fluctuations, 19-23 September 2005, Salamanc

Non-Gaussianity of resistance fluctuations near electrical breakdown

We study the resistance fluctuation distribution of a thin film near electrical breakdown. The film is modeled as a stationary resistor networkunder biased percolation. Depending on the value of the external current,on the system sizes and on the level of internal disorder, the fluctuation distribution can exhibit a non-Gaussian behavior. We analyze this non-Gaussianity in terms of the generalized Gumbel distribution recently introduced in the context of highly correlated systems near criticality. We find that when the average fraction of defects approaches the random percolation threshold, the resistance fluctuation distribution is well described by the universal behavior of the Bramwell-Holdsworth-Pinton distribution.Comment: 3 figures, accepted for publication on Semicond Sci Tec

Nonlinear supratransmission and bistability in the Fermi-Pasta-Ulam model

The recently discovered phenomenon of nonlinear supratransmission consists in a sudden increase of the amplitude of a transmitted wave triggered by the excitation of nonlinear localized modes of the medium. We examine this process for the Fermi-Pasta-Ulam chain, sinusoidally driven at one edge and damped at the other. The supratransmission regime occurs for driving frequencies above the upper band-edge and originates from direct moving discrete breather creation. We derive approximate analytical estimates of the supratransmission threshold, which are in excellent agreement with numerics. When analysing the long-time behavior, we discover that, below the supratransmission threshold, a conducting stationary state coexists with the insulating one. We explain the bistable nature of the energy flux in terms of the excitation of quasi-harmonic extended waves. This leads to the analytical calculation of a lower-transmission threshold which is also in reasonable agreement with numerical experiments.Comment: 8 pages, 9 figures. Phys. Rev. E (accepted

Energetics of critical oscillators in active bacterial baths

We investigate the nonequilibrium energetics near a critical point of a non-linear oscillator immersed in an active bacterial bath. At the critical point, we reveal a scaling exponent of the average power exerted by a constant non-conservative torque 〈W‧ 〉 ∼ (Da/τ)1/4, where Da is the effective diffusivity and τ the correlation time of the bacterial bath described by a Gaussian colored noise. Other features that we investigate are the average stationary power and the variance of the work both below and above the saddle-node bifurcation. Above the bifurcation, the average power attains an optimal, minimum value for finite τ that is below its zero-temperature limit. Furthermore, we reveal a finite-time uncertainty relation for active matter which leads to values of the Fano factor of the work that can be below 2kBTeff, with Teff the effective temperature of the oscillator in the bacterial bath. We analyze different Markovian approximations to describe the nonequilibrium stationary state of the system. Finally, we illustrate our results in the experimental context by considering the example of driven colloidal particles in periodic optical potentials within an E. Coli bacterial bath

Obese patients with a binge eating disorder have an unfavorable metabolic and inflammatory profile

To evaluate whether obese patients with a binge eating disorder (BED) have an altered metabolic and inflammatory profile related to their eating behaviors compared with non-BED obese.A total of 115 White obese patients consecutively recruited underwent biochemical, anthropometrical evaluation, and a 75-g oral glucose tolerance test. Patients answered the Binge Eating Scale and were interviewed by a psychiatrist. The patients were subsequently divided into 2 groups according to diagnosis: non-BED obese (n = 85) and BED obese (n = 30). Structural equation modeling analysis was performed to elucidate the relation between eating behaviors and metabolic and inflammatory profile.BED obese exhibited significantly higher percentages of altered eating behaviors, body mass index (P < 0.001), waist circumference (P < 0.01), fat mass (P < 0.001), and a lower lean mass (P < 0.001) when compared with non-BED obese. Binge eating disorder obese also had a worse metabolic and inflammatory profile, exhibiting significantly lower high-density lipoprotein cholesterol levels (P < 0.05), and higher levels of glycated hemoglobin (P < 0.01), uric acid (P < 0.05), erythrocyte sedimentation rate (P < 0.001), high-sensitive C-reactive protein (P < 0.01), and white blood cell counts (P < 0.01). Higher fasting insulin (P < 0.01) and higher insulin resistance (P < 0.01), assessed by homeostasis model assessment index and visceral adiposity index (P < 0.001), were observed among BED obese. All differences remained significant after adjusting for body mass index. No significant differences in fasting plasma glucose or 2-hour postchallenge plasma glucose were found. Structural equation modeling analysis confirmed the relation between the altered eating behaviors of BED and the metabolic and inflammatory profile.Binge eating disorder obese exhibited an unfavorable metabolic and inflammatory profile, which is related to their characteristic eating habits

Tunical plication in the management of penile curvature due La Peyronie’s disease. Our experience on 47 cases.

BACKGROUND: Peyronie’s disease is an acquired connective tissue disorder of the penile tunica albuginea with fibrosis and inflammation. The disease produces palpable plaques, penile curvature and pain during erections. Patients report negative effects in four major domains: physical appearance and self-image, sexual function and performance. These changes damage sexual life and compromise the quality of life. Our objective is to review the patient's sexual life after penile tunical plicature using the International Index of Erectile Function (IIEF) and the Sexual Encounter Profile (SEP) questionnaires. METHODS: A total of 47 patients with Peyronie's disease (PD) were enrolled at our urology department and they underwent correction of penile deviation between February 2009 and March 2010. Mean patient age was 56 years and mean follow-up was 24 months. Patients with painless PD plaque with no progression in angulation for at least 12 months were chosen for surgery. They underwent a penile tunical plication. IIEF and SEP questionnaire were administered to all patients. RESULTS: Of all treated patients, 94% were able to insert their penis in the partner's vagina (p<0.01; SEP question 2), compared with 62% preoperatively and 90% of them was satisfied overall with the sexual intercourse (p<0.01; SEP question 5) .Patients had a significantly higher endpoint and a greater change from baseline for the remaining SEP questions related to achievement of an erection, satisfaction of erection hardness (SEP questions 1 and 4; p < 0:001). We reported a significant improvement in the IIEF scores (from a baseline total score of 25.2 +/- 3.2 to a final score of 38.3 +/- 5.2; P<0.01). It resulted in significantly higher endpoint IIEF scores across all five IIEF domains: Erectile Function, Intercourse Satisfaction, Orgasmic Function, Sexual Desire and Overall Satisfaction. The main complaint was penile shortening (28 patients, 60%), feeling of the suture during flaccidity and tumescence (37 patients, 80%). CONCLUSION: Patient quality of life improved after surgery thanks to the improvement of their sexual life. The complications are unimportant and few bother symptoms are reported. The significant improvement in erectile function was also supported by IIEF and SEP questionnaire data. Nowadays tunical plication is a safe, advantageous and useful technique to treat patients suffering of Peyronie’s disease

Kinetic theory for non-equilibrium stationary states in long-range interacting systems

We study long-range interacting systems perturbed by external stochastic forces. Unlike the case of short-range systems, where stochastic forces usually act locally on each particle, here we consider perturbations by external stochastic fields. The system reaches stationary states where external forces balance dissipation on average. These states do not respect detailed balance and support non-vanishing fluxes of conserved quantities. We generalize the kinetic theory of isolated long-range systems to describe the dynamics of this non-equilibrium problem. The kinetic equation that we obtain applies to plasmas, self-gravitating systems, and to a broad class of other systems. Our theoretical results hold for homogeneous states, but may also be generalized to apply to inhomogeneous states. We obtain an excellent agreement between our theoretical predictions and numerical simulations. We discuss possible applications to describe non-equilibrium phase transitions.Comment: 11 pages, 2 figures; v2: small changes, close to the published versio

Supersonic Discrete Kink-Solitons and Sinusoidal Patterns with "Magic" wavenumber in Anharmonic Lattices

The sharp pulse method is applied to Fermi-Pasta-Ulam (FPU) and Lennard-Jones (LJ) anharmonic lattices. Numerical simulations reveal the presence of high energy strongly localized ``discrete'' kink-solitons (DK), which move with supersonic velocities that are proportional to kink amplitudes. For small amplitudes, the DK's of the FPU lattice reduce to the well-known ``continuous'' kink-soliton solutions of the modified Korteweg-de Vries equation. For high amplitudes, we obtain a consistent description of these DK's in terms of approximate solutions of the lattice equations that are obtained by restricting to a bounded support in space exact solutions with sinusoidal pattern characterized by the ``magic'' wavenumber $k=2\pi/3$. Relative displacement patterns, velocity versus amplitude, dispersion relation and exponential tails found in numerical simulations are shown to agree very well with analytical predictions, for both FPU and LJ lattices.Comment: Europhysics Letters (in print

New EU Regulations on pork labelling and their potential for improving a holistic food policy approach

The choice of food inevitably interferes on the nutritional and organic balance through the quality and the amount of certain nutrients. In addition, food contributes to the maintenance of cultural identities because food choices identify their fundamental aspects and has far-reaching implications on the availability of resources, with an inevitable impact on the fate of future generations. From this background comes the concept of “ethical food” that involves the understanding and awareness of food origin from a holistic point of view and therefore provides a useful tool to make responsible food choices. In the case of food of animal origin, this choice aims to ensure a farming animal welfare, the guarantee of human health and the environmental protection. In Europe, one of the tools to achieve this goal is the food labelling, whereby the information is clear, understandable and transparent, in accordance with specific Community rules. The Regulation (EU) No 1169/2011 set out the principles, the requirements and the responsibilities, to provide an accurate and understandable information about food. On April 1 2015 the Commission Regulation (EU) No 1337/2013 entered into force, laying down additional rules for the labelling of pork, with the goal to increase transparency by providing precise information on the origin of swine products. It will be compulsory for food business operators who will indicate, on the label of the marketed meat, the place of animals’ rearing and slaughtering. In case of meat from animals born, raised and slaughtered in the same country, the place of birth will instead appear on a voluntary basis. A full and transparent information is the first step of the ´´right to know´´ way, assumed as an awareness passage to consumers able to make free but responsible choices. This option is essential for a full guarantee food policy inside the protection of free trade and can be considered a transition from a single rules legislation (food legislation) to a regulation systematic approach (food law)