Verified software: theories, tools and experiments

The importance of verification for software products is being increasingly appreciated in industry, although still not to the level to make it a standard approach to high quality software in industry. Since 2005, a global initiative has been underway, started by eminent researchers in both industry and academia, with the aim of establishing and disseminating a culture of software verification from first principles by means of theories, tools and experiments. This special section contains a selection of contributions originally presented at the 2008 Workshop on Tools at VSTTE 2008, the conference on Verified Software: Theories, Tools and Experiments, in Toronto. The VSTTE series of conferences and workshops focuses on the challenge of verifying software systems. Within VSTTE, the scope of the Tools workshop are implementations and enabling techniques for program verifiers, which are important ingredients for the dissemination of principles and techniques among industrial practitioners. This special section complements a sister special section of the Journal on Formal Aspects of computing, Springer. While the FACJ papers address more foundational aspects of tool-based verification and tool construction, the present section presents two toolsets, reflections on usability for verification tools and a novel abstraction technique.     

A unified methodology for the evaluation of accessibility and usability of mobile applications

This article reports a unified methodology developed to evaluate the accessibility and usability of mobile computing applications, which is intended to guarantee universal access as far as possible. As a basis for the methodology, this paper presents an analysis of the accessibility guidelines, conducted to take into account the specificity of mobile systems, as well as a set of usability heuristics, specifically devised for mobile computing. Finally, it presents the results of the application of the proposed methodology to applications that have been semi-automatically developed by the MAIS Designer, a new design tool that provides applications suited to different mobile devices.     

Computational and experimental approaches assess the interactions between bovine beta-lactoglobulin and synthetic compounds of pharmacological interest

Extending a previous investigation, the ability of binding to the model calycin beta-lactoglobulin (BLG) was evaluated both in silico and in vitro for several fluorine-containing (semi-)synthetic molecules of pharmacological and pharmaceutical interest (antibiotics, vastatins, steroid drugs). Simulation procedures included molecular docking according to a Montecarlo-simulated annealing protocol and molecular dynamics; heteronuclear NMR and denaturant gradient gel electrophoresis were the selected experimental techniques. For the tested drugs, ranking of the binding affinity was consistently assessed by computation and by experiment. The affinity for BLG increased in the sequence: 5-fluorosalycilic acid相似文献   

Impact on the water column biogeochemistry of a Mediterranean mussel and fish farm

We investigated and compared the impact of organic loads due to the biodeposition of mussel and fish farms on the water column of a coastal area of the Tyrrhenian Sea (Western Mediterranean). Physico-chemical data (including oxygen, nutrients. DOC and particulate organic matter), microbial variables (picoplankton and picophytoplankton density and biomass) and phytoplankton biomass (as chlorophyll-a) were determined on a monthly basis from March 1997 to February 1998. The results of this study indicate that both fish farm and mussel culture did not alter significantly dissolved inorganic phosphorus and chlorophyll-a values, while inorganic nitrogen concentrations were higher in mussel farm area. However, waters overlying the fish farm presented significantly higher DOC concentrations. In contrast, no significant differences were observed comparing particulate matter concentrations. The increased DOC concentrations determined a response of the heterotrophic fraction of picoplankton, while picophytoplankton, likewise phytoplankton. did not display differences among fish or mussel farms and control site. From the analysis of the different microbial components, it is possible to conclude that the impact of fish farms is evident only for the heterotrophic components. The comparative analysis of the mussel biodeposition and fish-farm impact revealed that mussel farms induced a considerably lower disturbance, apparently limited to an increased density and biomass of microbial assemblages beneath the mussel cultures.     

The sleep inducing factor oleamide is produced by mouse neuroblastoma cells

Cis-9,10-octadecenoamide (oleamide) was isolated from the cerebrospinal fluid of sleep-deprived mammals and shown to induce sleep in rats. The enzyme catalyzing the hydrolysis of the amide bond of oleamide as well as of anandamide, the putative endogenous ligand of cannabinoid receptors, was purified from rat liver, cloned, shown to be expressed also in brain and named fatty acid amide hydrolase (FAAH). The enzymatic synthesis of oleamide from oleic acid and ammonia by rat brain microsomes has been also described. However, no evidence has been reported so far on the neuronal origin of oleamide, necessary in order to postulate for this compound a role as a neuromodulator. Here we show for the first time that oleamide is produced by a neuronal cell type and that its biosynthesis in intact neurons is not likely to occur through the direct condensation of oleic acid and ammonia. A lipid metabolite was extracted and purified from mouse neuroblastoma N18TG2 cells through a sequence of chromatographic steps and characterized as oleamide by means of gas chromatography/electron impact mass spectrometry (GC/EIMS). The amount of oleamide, as estimated by GC analyses carried out in comparison with known amounts of synthetic oleamide, was 55.0+/-09.5 pmols/10(7) cells, compared to less than 0.7 pmol/10(7) cells for anandamide in the same cells. When N18TG2 cells were prelabeled with [14C]oleic acid and the lipids extracted and purified, a radioactive component with the same chromatographic behavior as oleamide was found whose levels: (1) were not significantly influenced by stimulation with ionomycin; (2) were slightly increased by incubation with FAAH inhibitor phenyl-methyl-sulphonyl-fluoride (PMSF); (3) appeared to correlate with [14C]oleic acid incorporation into phospholipids but not with free [14C]oleic acid levels. N18TG2 cell membranes were shown to contain an enzymatic activity catalyzing the synthesis of oleamide from oleic acid and ammonia. This activity was inhibited by FAAH selective inhibitors arachidonoyltrifluoromethylketone and methylarachidonoylfluorophosphonate, as well as by an excess of anandamide, and by PMSF at the same concentration which increased oleamide formation in intact cells. These data suggest that a FAAH-like enzyme working "in reverse" may be responsible for the formation of oleamide in cell-free preparations but not in whole cells.     

Tools and algorithms for the construction and analysis of systems: a special issue for TACAS 2017

International Journal on Software Tools for Technology Transfer - This special issue of Software Tools for Technology Transfer presents extended versions of two selected papers from the 23rd...     

On the accessibility of Moodle 2 by visually impaired users,with a focus on mathematical content

In this paper we study the accessibility by visually impaired people of the learning management system (LMS) Moodle 2. The study is conducted by testing four different visually impaired subjects, with different degrees of disability and performing different tasks connected to different roles in the LMS. A peculiar focus is given to the accessibility of content involving mathematics. At the end of the paper, some recommendations to improve the accessibility of Moodle 2 are given.     

Solubility of supercritical gases in organic liquids

Chrastil (1982) [6] demonstrated that the solubility of a substance in a supercritical fluid (SCF) can be correlated with the density of the pure supercritical gas. Therefore, Chrastil's equation permits calculation of the supercritical phase composition of binary SCF + substance mixture based on the knowledge of the supercritical gas density and avoiding the use of equation of state based models.In this work, it is demonstrated that the supercritical fluid density also defines the liquid phase composition of binary systems; a density-dependent relationship is presented to calculate the solubility of supercritical gases in organic liquids. The isothermal solubility of several gases commonly employed in supercritical processing, such as carbon dioxide, methane, and ethane, in different organic liquids, including alkanes, alkenes, alcohols, acids, ketones, esters, terpenes and aromatic compounds, was successfully correlated as a function solely of the pure supercritical fluid density. As an application, pressure vs. composition phase diagrams of binary SCF + substance mixtures were obtained circumventing the use of equation of state models.