461 research outputs found
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 ăW⧠ă ⌠(Da/Ï)1/4, where Da is the effective diffusivity and Ï 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 Ï 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 (nâ=â85) and BED obese (nâ=â30). 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 (Pâ<â0.001), waist circumference (Pâ<â0.01), fat mass (Pâ<â0.001), and a lower lean mass (Pâ<â0.001) 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 (Pâ<â0.05), and higher levels of glycated hemoglobin (Pâ<â0.01), uric acid (Pâ<â0.05), erythrocyte sedimentation rate (Pâ<â0.001), high-sensitive C-reactive protein (Pâ<â0.01), and white blood cell counts (Pâ<â0.01). Higher fasting insulin (Pâ<â0.01) and higher insulin resistance (Pâ<â0.01), assessed by homeostasis model assessment index and visceral adiposity index (Pâ<â0.001), 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 Peyronieâs disease. Our experience on 47 cases.
BACKGROUND: Peyronieâs 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 Peyronieâs 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 . 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 âethical foodâ 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 animalsâ 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 ÂŽÂŽright to knowÂŽÂŽ 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)
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