Design of an analog/digital truly random number generator

An analog-digital system is presented for the generation of truly random (aperiodic) digital sequences. This model is based on a very simple piecewise-linear discrete map which is suitable for implementation using monolithic analog sampled-data techniques. Simulation results are given illustrating the optimum choice of the model parameters. Circuit implementations are reported for the discrete map using both switched-capacitor (SC) and switched-current (SI) techniques. The layout of a SI prototype in a 3-μm n-well double-polysilicon double-metal technology is included

Loop Corrections and Naturalness in a Chiral Effective Field Theory

The loop expansion is applied to a chiral effective hadronic lagrangian; with the techniques of Infrared Regularization, it is possible to separate out the short-range contributions and to write them as local products of fields that are already present in our lagrangian. (The appropriate field variables must be re-defined at each order in loops.) The corresponding parameters implicitly include short-range effects to all orders in the interaction, so these effects need not be calculated explicitly. The remaining (long-range) contributions that must be calculated are nonlocal and resemble those in conventional nuclear-structure calculations. Nonlinear isoscalar scalar $(\sigma)$ and vector $(\omega)$ meson interactions are included, which incorporate many-nucleon forces and nucleon substructure. Calculations are carried out at the two-loop level to illustrate these techniques at finite nuclear densities and to verify that the coupling parameters remain natural when fitted to the empirical properties of equilibrium nuclear matter. Contributions from the $\omega N$ tensor coupling are also discussed.Comment: 22 pages, 6 figure

Proximity effect gaps in S/N/FI structures

We study the proximity effect in hybrid structures consisting of superconductor and ferromagnetic insulator separated by a normal diffusive metal (S/N/FI structures). These stuctures were proposed to realize the absolute spin-valve effect. We pay special attention to the gaps in the density of states of the normal part. We show that the effect of the ferromagnet is twofold: It not only shifts the density of states but also provides suppression of the gap. The mechanism of this suppression is remarkably similar to that due to magnetic impurities. Our results are obtained from the solution of one-dimensional Usadel equation supplemented with boundary conditions for matrix current at both interfaces.Comment: Published in The European Physical Journal

A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images. I Method description

We present a new non-parametric method to quantify morphologies of galaxies based on a particular family of learning machines called support vector machines. The method, that can be seen as a generalization of the classical CAS classification but with an unlimited number of dimensions and non-linear boundaries between decision regions, is fully automated and thus particularly well adapted to large cosmological surveys. The source code is available for download at http://www.lesia.obspm.fr/~huertas/galsvm.html To test the method, we use a seeing limited near-infrared ($K_s$ band, $2,16\mu m$) sample observed with WIRCam at CFHT at a median redshift of $z\sim0.8$. The machine is trained with a simulated sample built from a local visually classified sample from the SDSS chosen in the high-redshift sample's rest-frame (i band, $0.77\mu m$) and artificially redshifted to match the observing conditions. We use a 12-dimensional volume, including 5 morphological parameters and other caracteristics of galaxies such as luminosity and redshift. We show that a qualitative separation in two main morphological types (late type and early type) can be obtained with an error lower than 20% up to the completeness limit of the sample ($KAB\sim 22$) which is more than 2 times better that what would be obtained with a classical C/A classification on the same sample and indeed comparable to space data. The method is optimized to solve a specific problem, offering an objective and automated estimate of errors that enables a straightforward comparison with other surveys.Comment: 11 pages, 7 figures, 3 tables. Submitted to A&A. High resolution images are available on reques

Wave energy in Europe: Views on experiences and progress to date

publisher: Elsevier articletitle: Wave energy in Europe: Views on experiences and progress to date journaltitle: International Journal of Marine Energy articlelink: http://dx.doi.org/10.1016/j.ijome.2015.09.001 content_type: article copyright: © 2015 Elsevier Ltd. All rights reserved

UBQLN4 Represses Homologous Recombination and Is Overexpressed in Aggressive Tumors

Genomic instability can be a hallmark of both human genetic disease and cancer. We identify a deleterious UBQLN4 mutation in families with an autosomal recessive syndrome reminiscent of genome instability disorders. UBQLN4 deficiency leads to increased sensitivity to genotoxic stress and delayed DNA double-strand break (DSB) repair. The proteasomal shuttle factor UBQLN4 is phosphorylated by ATM and interacts with ubiquitylated MRE11 to mediate early steps of homologous recombination-mediated DSB repair (HRR). Loss of UBQLN4 leads to chromatin retention of MRE11, promoting non-physiological HRR activity in vitro and in vivo. Conversely, UBQLN4 overexpression represses HRR and favors non-homologous end joining. Moreover, we find UBQLN4 overexpressed in aggressive tumors. In line with an HRR defect in these tumors, UBQLN4 overexpression is associated with PARP1 inhibitor sensitivity. UBQLN4 therefore curtails HRR activity through removal of MRE11 from damaged chromatin and thus offers a therapeutic window for PARP1 inhibitor treatment in UBQLN4-overexpressing tumors

Proximity effect-assisted absorption of spin currents in superconductors

The injection of pure spin current into superconductors by the dynamics of a ferromagnetic contact is studied theoretically. Taking into account suppression of the order parameter at the interfaces (inverse proximity effect) and the energy-dependence of spin-flip scattering, we determine the temperature-dependent ferromagnetic resonance linewidth broadening. Our results agree with recent experiments in Nb|permalloy bilayers [C. Bell et al., arXiv:cond-mat/0702461].Comment: 4 page

A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images. II. Quantifying morphological k-correction in the COSMOS field at 1<z<2: Ks band vs. I band

We quantify the effects of \emph{morphological k-correction} at $1<z<2$ by comparing morphologies measured in the K and I-bands in the COSMOS area. Ks-band data have indeed the advantage of probing old stellar populations for $z<2$, enabling a determination of galaxy morphological types unaffected by recent star formation. In paper I we presented a new non-parametric method to quantify morphologies of galaxies on seeing limited images based on support vector machines. Here we use this method to classify $\sim$$50 000$ $Ks$ selected galaxies in the COSMOS area observed with WIRCam at CFHT. The obtained classification is used to investigate the redshift distributions and number counts per morphological type up to $z\sim2$ and to compare to the results obtained with HST/ACS in the I-band on the same objects from other works. We associate to every galaxy with $Ks<21.5$ and $z<2$ a probability between 0 and 1 of being late-type or early-type. The classification is found to be reliable up to $z\sim2$. The mean probability is $p\sim0.8$. It decreases with redshift and with size, especially for the early-type population but remains above $p\sim0.7$. The classification is globally in good agreement with the one obtained using HST/ACS for $z<1$. Above $z\sim1$, the I-band classification tends to find less early-type galaxies than the Ks-band one by a factor $\sim$1.5 which might be a consequence of morphological k-correction effects. We argue therefore that studies based on I-band HST/ACS classifications at $z>1$ could be underestimating the elliptical population. [abridged]Comment: accepted for publication in A&A, updated with referee comments, 12 pages, 10 figure

Dynamic exchange coupling and Gilbert damping in magnetic multilayers

We theoretically study dynamic properties of thin ferromagnetic films in contact with normal metals. Moving magnetizations cause a flow of spins into adjacent conductors, which relax by spin flip, scatter back into the ferromagnet, or are absorbed by another ferromagnet. Relaxation of spins outside the moving magnetization enhances the overall damping of the magnetization dynamics in accordance with the Gilbert phenomenology. Transfer of spins between different ferromagnets by these nonequilibrium spin currents leads to a long-ranged dynamic exchange interaction and novel collective excitation modes. Our predictions agree well with recent ferromagnetic-resonance experiments on ultrathin magnetic films.Comment: 15 pages, 3 figures, for MMM'02 proceeding

Intense Physical Exercise Reduces Overt Attentional Capture

The abrupt onset of a visual stimulus typically results in overt attentional capture, which can be quantified by saccadic eye movements. Here, we tested whether attentional capture following onset of task-irrelevant visual stimuli (new object) is reduced after a bout of intense physical exercise. A group of participants performed a visual search task in two different activity conditions: Rest - without any prior effort; Effort - immediately after an acute bout of intense exercise. The results showed that participants exhibited: 1) slower reaction time of the first saccade toward the target when a new object was simultaneously presented in the visual field, but only in the rest activity condition; 2) more saccades to the new object in the rest activity condition than in the effort activity condition. We suggest that immediately after an acute bout of effort, participants improved their ability to inhibit irrelevant (distracting) stimuli. Key words: Acute exercise, effort, eye movements, attention, exogenous attention, physical activity