Interval Slopes as Numerical Abstract Domain for Floating-Point Variables

The design of embedded control systems is mainly done with model-based tools such as Matlab/Simulink. Numerical simulation is the central technique of development and verification of such tools. Floating-point arithmetic, that is well-known to only provide approximated results, is omnipresent in this activity. In order to validate the behaviors of numerical simulations using abstract interpretation-based static analysis, we present, theoretically and with experiments, a new partially relational abstract domain dedicated to floating-point variables. It comes from interval expansion of non-linear functions using slopes and it is able to mimic all the behaviors of the floating-point arithmetic. Hence it is adapted to prove the absence of run-time errors or to analyze the numerical precision of embedded control systems

Transjugular Intrahepatic Portosystemic Shunts With Covered Stents Increase Transplant-Free Survival of Patients With Cirrhosis and Recurrent Ascites

BACKGROUND & AIMS: There is controversy over the ability of transjugular intrahepatic portosystemic shunts (TIPS) to increase survival times of patients with cirrhosis and refractory ascites. The high rate of shunt dysfunction with the use of uncovered stents counteracts the benefits of TIPS. We performed a randomized controlled trial to determine the effects of TIPS with stents covered with polytetrafluoroethylene in these patients. METHODS: We performed a prospective study of 62 patients with cirrhosis and at least 2 large-volume paracenteses within a period of at least 3 weeks; the study was performed at 4 tertiary care centers in France from August 2005 through December 2012. Patients were randomly assigned to groups that received covered TIPS (n = 29) or large-volume paracenteses and albumin as necessary (LVP+A, n = 33). All patients maintained a low-salt diet and were examined at 1 month after the procedure then every 3 months until 1 year. At each visit, liver disease-related complications, treatment modifications, and clinical and biochemical variables needed to calculate Child-Pugh and Model for End-Stage Liver Disease scores were recorded. Doppler ultrasonography was performed at the start of the study and then at 6 and 12 months after the procedure. The primary study end point was survival without a liver transplant for 1 year after the procedure. RESULTS: A higher proportion of patients in the TIPS group (93%) met the primary end point than in the LVP+A group (52%) (P = .003). The total number of paracenteses was 32 in the TIPS group vs 320 in the LVP+A group. Higher proportions of patients in the LVP+A group had portal hypertension-related bleeding (18% vs 0%; P = .01) or hernia-related complications (18% vs 0%; P = .01) than in the TIPS group. Patients in LVP+A group had twice as many days of hospitalization (35 days) as the TIPS group (17 days) (P = .04). The 1-year probability of remaining free of encephalopathy was 65% for each group. CONCLUSIONS: In a randomized trial, we found covered stents for TIPS to increase the proportion of patients with cirrhosis and recurrent ascites who survive transplantation-free for 1 year, compared with patients given repeated LVP+A. These findings support TIPS as the first-line intervention in such patients. ClinicalTrials.gov ID: NCT00222014

Géographie et cultures n° 2

Lieu de confrontation d'idées et d'expériences, Géographie et cultures répond à l'intérêt renouvelé de la géographie pour les faits de civilisation, et des sciences sociales pour l'environ­nement. Quel est le rôle de l'espace géographique dans la structuration d'une culture ? Comment se perçoit l'influence d'une civilisation dans l'organisation par les hommes de leur espace et de leur milieu ? Un domaine fécond et encore peu exploré s'ouvre à l'analyse, lorsqu'on observe les relations entre phénomènes géographiques (espace, milieu, territoire, paysage, régions...) et phénomènes culturels (identité, valeur, mémoire, repré­sentations...). Cette revue de géographie culturelle et d'ethnogéographie s'adresse à tous ceux qui s'interrogent sur les interactions entre espace et culture, sous toutes les latitudes et à toutes les échelles : historiens, ethnologues, sociologues, psychologues, géographes ou écrivains

An Abstract Domain to Infer Octagonal Constraints with Absolute Value

International audienceThe octagon abstract domain, devoted to discovering octagonal constraints (also called Unit Two Variable Per Inequality or UTVPI constraints) of a program, is one of the most commonly used numerical abstractions in practice, due to its quadratic memory complexity and cubic time complexity. However, the octagon domain itself is restricted to express convex sets and has limitations in handling non-convex properties which are sometimes required for proving some numerical properties in a program. In this paper, we intend to extend the octagon abstract domain with absolute value, to infer certain non-convex properties by exploiting the absolute value function. More precisely, the new domain can infer relations of the form {±X ± Y ≤ c, ±X ± |Y| ≤ d, ±|X| ± |Y| ≤ e}. We provide algorithms for domain operations such that the new domain still enjoys the same asymptotic complexity as the octagon domain. Moreover, we present an approach to support strict inequalities over rational or real-valued variables in this domain, which also fits for the octagon domain. Experimental results of our prototype are encouraging; The new domain is scalable and able to find non-convex invariants of interest in practice but without too much overhead (compared with that using octagons)

Sequential Nature of (p,3p) Two-Proton Knockout from Neutron-Rich Nuclei

7 pags., 4 figs.Twenty-one two-proton knockout (p,3p) cross sections were measured from neutron-rich nuclei at ∼250 MeV/nucleon in inverse kinematics. The angular distribution of the three emitted protons was determined for the first time, demonstrating that the (p,3p) kinematics are consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p,3p) over (p,2p) inclusive cross sections follow the trend of other many-nucleon removal reactions, further reinforcing the sequential nature of (p,3p) in neutron-rich nuclei.We thank the RIBF and BigRIPS teams for providing a stable beam and optimum settings over the two experimental campaigns. A. F. acknowledges support from the DFG under Grant No. SFB1245. M. G.-R. acknowledges support from the Alexander von Humboldt foundation. A. O. thanks the European Research Council for its support through ERC Grant No. MINOS-258567, the JSPS Japanese Society for the Promotion of Science for the long-term fellowship L-13520, the German DFG for its support from the SFB Grant No. 1245, and the Alexander von Humboldt Foundation for its support. K. Mo. acknowledges support from German BMBF Grant No. 05P15PKFNA. M. L. C., M. L., and V. W. acknowledge support from German BMBF Grants No. 05P15RDFN1, and No. 05P19RDFN1, as well as DFG Grant No. SFB 1245. L. X. C. and B. D. L. are supported by the Vietnam MOST through Physics Development Program Grant No. Ð TÐ LCN.25/18 and acknowledge the Radioactive Isotope Physics Laboratory of the RIKEN Nishina Center for supporting their stay during the experiment. A. J. and V. V. acknowledge support from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2- P. U.K. participants acknowledge support from the Science and Technology Facilities Council (STFC). Collaborators from I. M. P. were supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences. R. T. was supported by the JSPS Grant-in-Aid for JSPS Research Fellows JP14J08718. Zs. D., Z. K., and Zs. V. acknowledge the support from Projects No. OTKA K128947 and No. GINOP-2.3.3-15-2016-00034. C. Santamaria acknowledges support by the IPA program at the RIKEN Nishina Center