experimental evaluation of numerical domains for inferring ranges

Abstract Among the numerical abstract domains for detecting linear relationships between program variables, the polyhedra domain is, from a purely theoretical point of view, the most precise one. Other domains, such as intervals, octagons and parallelotopes, are less expressive but generally more efficient. We focus our attention on interval constraints and, using a suite of benchmarks, we experimentally show that, in practice, polyhedra may often compute results less precise than the other domains, due to the use of the widening operator

Concentrated suspensions of Brownian beads in water: dynamic heterogeneities trough a simple experimental technique

Concentrated suspensions of Brownian hard-spheres in water are an epitome for understanding the glassy dynamics of both soft materials and supercooled molecular liquids. From an experimental point of view, such systems are especially suited to perform particle tracking easily, and, therefore, are a benchmark for novel optical techniques, applicable when primary particles cannot be resolved. Differential Variance Analysis (DVA) is one such novel technique that simplifies significantly the characterization of structural relaxation processes of soft glassy materials, since it is directly applicable to digital image sequences of the sample. DVA succeeds in monitoring not only the average dynamics, but also its spatio-temporal fluctuations, known as dynamic heterogeneities. In this work, we study the dynamics of dense suspensions of Brownian beads in water, imaged through digital video-microscopy, by using both DVA and single-particle tracking. We focus on two commonly used signatures of dynamic heterogeneities: the dynamic susceptibility, $\chi_4$, and the non-Gaussian parameter, $\alpha_2$. By direct comparison of these two quantities, we are able to highlight similarities and differences. We do confirm that $\chi_4$ and $\alpha_2$ provide qualitatively similar information, but we find quantitative discrepancies in the scalings of characteristic time and length scale on approaching the glass transition.Comment: The original publication is available at http://www.scichina.com and http://www.springerlink.com http://engine.scichina.com/publisher/scp/journal/SCPMA/doi/10.1007/s11433-019-9401-x?slug=abstrac

Brownian regime of finite- N corrections to particle motion in the XY Hamiltonian mean field model

International audienceWe study the dynamics of the N-particle system evolving in the XY hamiltonian mean field (HMF) model for a repulsive potential, when no phase transition occurs. Starting from a homogeneous distribution, particles evolve in a mean field created by the interaction with all others. This interaction does not change the homogeneous state of the system, and particle motion is approximately ballistic with small corrections. For initial particle data approaching a waterbag, it is explicitly proved that corrections to the ballistic velocities are in the form of independent brownian noises over a time scale diverging not slower than N^(2/5) as N → ∞, which proves the propagation of molecular chaos. Molecular dynamics simulations of the XY-HMF model confirm our analytical findings

Revaluation of the clinical and metabolic behavior of children with isolated growth hormone deficiency during GH treatment according to newly proposed note 39 of the Italian Medicines Agency (AIFA).

Purpose To evaluate the clinical and metabolic behavior of children with isolated growth hormone (GH)-deficiency (GHD), grouped according to the new AIFA criteria for the appropriateness of use and reimbursement of GH treatment in children. Methods The clinical and metabolic data of 310 prepubertal children (220 M, 90 F; mean age 10.8 years) grouped, according to new AIFA note 39, into group A (No 181 with a peak of GH 10 µg/L) were retrospectively analyzed. Group A and B, diagnosed as having GHD, were treated with GH for at least 24 months, while group C was analyzed only at baseline. Results At baseline, group A showed higher waist circumference than B (p=0.031) and C (p=0.041), while no difference in metabolic parameters was found between the 3 groups. After 12 and 24 months of treatment, group B showed lower height velocity (p<0.001 and p=0.049, respectively) than group A. As regards the metabolic parameters, both after 12 and 24 months of treatment, in group B we found higher fasting glucose (p<0.001 and p=0.020), insulin (p=0.002 and p=0.011), Homa-β (p=0.020 and p=0.015) and Homa-IR (both p=0.001) than group A, with concomitant lower QUICKI (both p<0.001) and HDL cholesterol (p=0.020 and p=0.011), without difference in other lipid parameters. The HbA1c levels, although always within the normal range, was found higher in group B than group A after 12 months (p=0.015). Conclusions Accordingly with the new AIFA criteria, the reduction of GH cut-off for GHD diagnosis can be supported by auxological and metabolic data. The real benefits from GH therapy in children with higher stimulated GH levels at diagnosis remains to better understand

Visceral Adiposity Index Is Associated with Insulin Sensitivity and Adipocytokine Levels in Newly Diagnosed Acromegalic Patients.

Context: The visceral adiposity index (VAI) has proved to be a marker of visceral adipose dysfunction, strongly associated with insulin sensitivity in both the general and specific populations of patients at metabolic risk. Objective: The objective of the study was to test VAI as a useful tool to assess early metabolic risk in acromegaly. Patients: Twenty-four newly diagnosed acromegalic patients (11 women and 13 men, aged 54.9 ± 13.6 yr) were grouped into those with normal (group A, n = 13, 54.2%) and those with high VAI (group B, n = 11, 45.8%). Outcome Measures: Glucose, hemoglobin A1c, nadir and area under the curve (AUC) of GH (AUCGH) during the oral glucose tolerance test, AUCCpeptide during a mixed-meal tolerance test, M value during euglycemic-hyperinsulinemic clamp, oral dispositional index (DIo), each component of the metabolic syndrome, leptin, adiponectin, TNF-α, and IL-6. Results: The VAI value was positively correlated with the age of patients (ρ = 0.408; P = 0.048), tumor volume (ρ = 0.638; P = 0.001), basal GH (ρ = 0.622; P = 0.001), nadir GH (ρ = 0.534; P = 0.007), AUCGH (ρ = 0.603; P = 0.002), IGF-I (ρ = 0.618; P = 0.001), TNF-α (ρ = 0.512; P = 0.010), and AUCCpeptide (ρ = 0.715; p<0.001) and negatively with adiponectin (ρ = −0.766; P < 0.001), M value (ρ = −0.818; P < 0.001), and DIo (ρ = −0.512; P = 0.011). Patients with high VAI showed significantly higher basal GH levels (P = 0.018), AUCGH (P = 0.047), IGF-I (P = 0.047), AUCCpeptide (P = 0.018), lower M value (P < 0.001), DIo (P = 0.006), and adiponectin levels (P < 0.001), despite the absence of a significantly higher prevalence in the overt metabolic syndrome and glucose tolerance abnormalities. AUCGH proved to be the main independent factor influencing VAI. Conclusions: In acromegaly, VAI appears to be associated with disease activity, adiponectin levels, and insulin sensitivity and secretion and is influenced independently by GH levels. VAI could therefore be used as an easy and useful new tool in daily clinical practice for the assessment of early metabolic risk associated with active acromegal