Generalized Approximate Survey Propagation for High-Dimensional Estimation

In Generalized Linear Estimation (GLE) problems, we seek to estimate a signal that is observed through a linear transform followed by a component-wise, possibly nonlinear and noisy, channel. In the Bayesian optimal setting, Generalized Approximate Message Passing (GAMP) is known to achieve optimal performance for GLE. However, its performance can significantly degrade whenever there is a mismatch between the assumed and the true generative model, a situation frequently encountered in practice. In this paper, we propose a new algorithm, named Generalized Approximate Survey Propagation (GASP), for solving GLE in the presence of prior or model mis-specifications. As a prototypical example, we consider the phase retrieval problem, where we show that GASP outperforms the corresponding GAMP, reducing the reconstruction threshold and, for certain choices of its parameters, approaching Bayesian optimal performance. Furthermore, we present a set of State Evolution equations that exactly characterize the dynamics of GASP in the high-dimensional limit

The psychosocial impact of assistive device scale: Italian validation in a cohort of nonambulant people with neuromotor disorders

The importance of adaptive seating system on body structure and function is widely accepted, but its impact on psychosocial aspects needs more consideration by health professionals. This article describes the Italian validation of the Psychosocial Impact of Assistive Device Scale (IT-PIADS) for non-ambulant people with neuromotor disorders. Once agreement has been given by the original authors, the scale was translated and adapted to the Italian culture. The IT-PIADS was administered to different wheelchairs users with heterogeneous diagnosis. The internal consistency and test-retest reliability were examined. Its concurrent validity was evaluated with the Italian version of the WheelCon-M-SF. The IT-PIADS was administered to 87 subjects. Cronbach's α was 0.92 (p < 0.05), and the testretest reliability (ICC) for competence, adaptability and self-esteem subscales were 0.96, 0.90, 0.93 respectively. The Pearson correlation coefficient of the IT-PIADS with the WheelCon-M-I-SF scores showed significant data for competence and adaptability subscales. Psychosocial perception on assistive devices can be reliably measure. The IT-PIADS showed good psychometric properties and it is possible to confirm its validity for clinical and research purposes. Nevertheless, before using this measure with greater confidence, further psychometric properties tests of the IT-PIADS are recommended

Finite size corrections to disordered systems on Erd\"{o}s-R\'enyi random graphs

We study the finite size corrections to the free energy density in disorder spin systems on sparse random graphs, using both replica theory and cavity method. We derive an analytical expressions for the $O(1/N)$ corrections in the replica symmetric phase as a linear combination of the free energies of open and closed chains. We perform a numerical check of the formulae on the Random Field Ising Model at zero temperature, by computing finite size corrections to the ground state energy density.Comment: Submitted to PR

The Random Fractional Matching Problem

We consider two formulations of the random-link fractional matching problem, a relaxed version of the more standard random-link (integer) matching problem. In one formulation, we allow each node to be linked to itself in the optimal matching configuration. In the other one, on the contrary, such a link is forbidden. Both problems have the same asymptotic average optimal cost of the random-link matching problem on the complete graph. Using a replica approach and previous results of W\"{a}stlund [Acta Mathematica 204, 91-150 (2010)], we analytically derive the finite-size corrections to the asymptotic optimal cost. We compare our results with numerical simulations and we discuss the main differences between random-link fractional matching problems and the random-link matching problem.Comment: 24 pages, 3 figure

Materia primordiale e Growing Design

Il particolare momento di crisi economica che il mondo occidentale sta attraversando, ha generato nel design alcune tendenze “autarchiche” che si sviluppano prevalentemente intorno a materie primordiali, basiche e naturalmente disponibili. Materiali al grado “zero” capaci di crescere, trasformarsi e rigenerarsi anche in vitro; materiali biologici e vivi dalle straordinarie potenzialità espressive e performative; materiali etici, sinceri e democratici perché realizzati con materia edibile o di scarto. E così, sotto il comune denominatore di una estetica del “primitivo” e dell’”imperfetto”, assistiamo ad un processo inversamente proporzionale in cui ad un maggior grado di sofisticazione tecnologica corrisponde paradossalmente un minor livello di ricercatezza estetico-formale.The economic crisis currently sweeping the western world has generated several “autarchic” trends primarily involving primordial, basic and naturally available materials. These “zero” degree materials can grow, transform and regenerate themselves even in vitro. They are live, biological materials with amazing expressive and performance potential, as well as being ethical, genuine and democratic because they are made with edible or waste material. Concealed behind this common denominator of “primitive” and “imperfect” aesthetics is an inversely proportional process; greater technological sophistication paradoxically corresponds to less aesthetic and formal refinement

The star-shaped space of solutions of the spherical negative perceptron

Empirical studies on the landscape of neural networks have shown that low-energy configurations are often found in complex connected structures, where zero-energy paths between pairs of distant solutions can be constructed. Here we consider the spherical negative perceptron, a prototypical non-convex neural network model framed as a continuous constraint satisfaction problem. We introduce a general analytical method for computing energy barriers in the simplex with vertex configurations sampled from the equilibrium. We find that in the over-parameterized regime the solution manifold displays simple connectivity properties. There exists a large geodesically convex component that is attractive for a wide range of optimization dynamics. Inside this region we identify a subset of atypical high-margin solutions that are geodesically connected with most other solutions, giving rise to a star-shaped geometry. We analytically characterize the organization of the connected space of solutions and show numerical evidence of a transition, at larger constraint densities, where the aforementioned simple geodesic connectivity breaks down.Comment: 27 pages, 16 figures, comments are welcom

Nerve growth factor is an autocrine survival factor for memory B lymphocytes

AbstractProduction of nerve growth factor (NGF) was assessed in cultures of human T and B lymphocytes and macrophages. NGF was constitutively produced by B cells only, which also expressed surface p140trk-A and p75NGFR molecules and hence efficiently bound and internalized the cytokine. Neutralization of endogenous NGF caused disappearance of Bcl-2 protein and apoptotic death of resting lymphocytes bearing surface IgG or IgA, a population comprising memory cells, while surface IgM/IgD “virgin” B lymphocytes were not affected. In vivo administration of neutralizing anti-NGF antibodies caused strong reduction in the titer of specific IgG in mice immunized with tetanus toxoid, nitrophenol, or arsonate and reduced numbers of surface IgG or IgA B lymphocytes. Thus, NGF is an autocrine survival factor for memory B lymphocytes

Near-field microwave techniques for micro – and nano - scale characterization in materials science

In this paper, the basic principles of Near-Field Microscopy will be reviewed with focus on the micro- and nano-scale resolution configurations for material science measurements. Results on doping profile, dielectric and magnetic properties will be presented, with details on the calibration protocols needed for quantitative estimation of the dielectric constant and of the permeability

Age and baseline values predict 12 and 24-month functional changes in type 2 SMA

The aim of this retrospective study was to establish the range of functional changes at 12 and 24-month in 267 type 2 Spinal Muscular Atrophy (SMA) patients with multiple assessments. We included 652 Hammersmith Functional Motor Scale Expanded (HFMSE) assessments at 12 month- and 305 at 24 month- intervals. The cohort was subdivided by functional level, Survival of Motor Neuron copy number and age. Stable scores (± 2 points) were found in 68% at 12 months and in 55% at 24 months. A decrease ≥2 points was found in 21% at 12 months and in 35% at 24 months. An increase ≥2 points was found in 11% at 12 months and 9.5% at 24 months. The risk of losing ≥2 points increased with age and HFMSE score at baseline both at 12 and 24-month. For each additional HFMSE point at baseline, the relative risk of a >2 point decline at 12 months increases by 5% before age 5 years (p = 0.023), by 8% between 5 and 13 (p<0.001) and by 26% after 13 years (p = 0.003). The combination of age and HFMSE scores at baseline increased the ability to predict progression in type 2 SMA