A functional formalization of on chip communications

This paper presents a formal model and a systematic approach to the validation of communication architectures at a high level of abstraction. This model is described mathematically by a function, named GeNoC. The correctness of GeNoC is expressed as a theorem, which states that messages emitted on the architecture reach their expected destination without any modification of their content. The model identifies the key constituents common to all on chip communication architectures, and their essential properties from which the correctness theorem is deduced. Each constituent is represented by a function that has no explicit definition but is constrained to satisfy the essential properties. Thus, the validation of a particular architecture is reduced to the proof that its concrete definition satisfies the essential properties. In practice, the model has been defined in the logic of the ACL2 theorem proving system. We illustrate our approach on several architectures that constitute concrete instances of the generic GeNoC model. Some of these applications come from industrial designs, such as the AMBA AHB bus or the Octagon network from ST Microelectronics. C. Delgado Kloos     

Phase transitions in wetting films at the surface of Ga–Pb alloys

Surface phase transitions at Ga-rich liquid surfaces have been investigated in Ga–Pb alloys with low lead content. In the region of the liquid–liquid miscibility gap, the Pb-rich liquid phase completely wets the surface of the Ga-rich phase at coexistence. Observations have been made of demixing and solidification of the Pb-rich liquid film. Ga-rich alloys, which are single-phase below the monotectic temperature, can be undercooled below the liquidus, as far as the metastable binodal line where the Pb-rich wetting liquid film forms and solidifies into thin {111} Pb crystals. These films completely redissolve upon reheating to the liquidus temperature. Freezing occurs at surfaces because of complete wetting of the liquid rich in the high melting point component and the hysteretic character of the solidification transformation. Such “surface” experiments allow assessment of the stable and metastable liquidus lines of the Ga–Pb phase diagram in the vicinity of the monotectic temperature.     

Normes d’imagerie et de fréquence subjective pour 1 760 mots monosyllabiques de la langue fran?aise.

This study aimed at providing subjective frequency and imageability norms for a sample of 1,760 monosyllabic French words and thereby, increasing the pool of normative data available for research in cognitive science and language processing. The results indicate that the reliability of the estimates is high, with coefficients ranging between .93 and .99 for the frequency and imageability ratings. External validity was investigated by calculating correlations with ratings drawn from all similar studies and for which the number of shared items was sufficient. These coefficients vary between .73 and .88 for subjective frequency and between .64 and .97 for imageability. The correlation between subjective frequency and imageability in the present study was significant and relatively high (r = .64). The implications of these results for the selection of experimental stimuli for research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis, characterization and biocidal properties of epoxy resins containing quaternary ammonium salts

Summary Quaternary ammonium salts (QAS) were covalently-bound to epoxy resins of different DP in two steps: addition of a N,N-dialkylaminoethanethiol followed by the quaternization of the tertiary amine by an alkylbromide (C₈H₁₇Br to C₁₄H₂₉Br). The products were characterized by ¹H NMR spectroscopy. The QAS-containing oligomers were used as polyols to prepare polyurethane (PU) films by reaction with a triisocyanate. The films show a good bactericidal activity against Escherichia coli, which is preserved after 6 months of immersion in water. Received: 30 December 1999/Revised version: 23 March 2000/Accepted: 23 March 2000     

VEGF-R2/Caveolin-1 Pathway of Undifferentiated ARPE-19 Retina Cells: A Potential Target as Anti-VEGF-A Therapy in Wet AMD by Resvega,an Omega-3/Polyphenol Combination

Age-related macular degeneration (AMD) is one of the main causes of deterioration in vision in adults aged 55 and older. In spite of therapies, the progression of the disease is often observed without reverse vision quality. In the present study, we explored whether, in undifferentiated ARPE-19 retinal cells, a disruption of the VEGF receptors (VEGF-R)/caveolin-1 (Cav-1)/protein kinases pathway could be a target for counteracting VEGF secretion. We highlight that Resvega^®, a combination of omega-3 fatty acids with an antioxidant, resveratrol, inhibits VEGF-A secretion in vitro by disrupting the dissociation of the VEGF-R2/Cav-1 complex into rafts and subsequently preventing MAPK activation. Moreover, DNA ChIP analysis reveals that this combination prevents the interaction between AP-1 and vegf-a and vegf-r2 gene promoters. By these pathways, Resvega could present a potential interest as nutritional complementation against AMD.     

From compressibility to structural investigation of sodium dodecyl sulphate — Part 2: A singular behavior under pressure

Investigations were carried out to elucidate the compression behavior of a powdered surfactant, sodium dodecyl sulphate (SDS), based on a comparison with the main component of a detergent formulation, i.e. the chorine provider (DCCNa). The energetic analysis based on the compression cycles highlighted a lower compressibility of SDS compared with DCCNa, especially due to its worse packing ability, larger elasticity and bad cohesion ability. Also, it pointed out that the pycnometric density seemed to be overrun under pressure whereas a residual porosity had been evidenced in the expanded tablets. DSC/DTA analysis, Raman spectroscopy as well as powder X-ray diffraction refuted the hypothesis of a physico-chemical transformation of SDS under pressure. This was in accordance with the morphology of the SDS particles, quite unchanged after compression. The pycnometric density measurements have been improved; firstly, it allowed to properly express the compaction ratio of the ejected SDS tablets, and secondly, it led to conclude to a reversible intrinsic compressibility for pressures higher than 50 MPa, explained by the predominant elastic behavior of SDS.     

Effect of cations on corrosion of zinc and carbon steel covered with chloride deposits under atmospheric conditions

The effect of sodium, calcium, and magnesium chlorides deposited on zinc and carbon steel surfaces was studied under atmospheric conditions. The cations strongly affected the corrosion rate of zinc, whereas they had a significantly lower impact on the corrosion of carbon steel. The corrosivity of cations of chloride salts for zinc increased in order of Mg²⁺ < Ca²⁺ < Na⁺. The higher corrosion resistance of zinc treated with calcium and magnesium chlorides was connected to prevention of formation of hydrozincite during zinc exposure in wet air. It was observed that zinc weight loss and the carbonate to simonkolleite ratio in corrosion products were correlating. The principal protective effect of bivalent cations can be seen in the decrease of pH of the surface electrolyte, which was caused by hydrolysis of such cations and subsequent formation of simonkolleite that blocked the cathodic sites.     

3D Finite-Element Simulation of a Square Silo with Flexible Walls

Most of the studies that have been published to evaluate stresses on silo walls during filling or discharge stages are based on a rigid wall assumption. In a 2D approach, the wall flexibility can be approximately modeled by using a corrective factor applied to the whole pressure distribution. It has been shown that such models are in agreement with experimental measurements on circular silos. But in square or rectangular silos, the variation of the stiffness of the wall due to vertical or horizontal stiffeners produces nonuniform wall deformations that are not taken into account in the previous axisymmetric 2D model. The aim of this paper is to present a full 3D modeling of the filling and discharge stages using a nonlinear finite-element method. The bulk material behavior is based on an elastoplastic law. Contact elements using a Mohr-Coulomb criterion simulate the interaction between the wall and the bulk material, and the flexibility of the silo structure is modeled with beam and shell elements. A detailed analysis of the numerical results computed for a square silo filled with wheat and discharged through a central outlet is presented and discussed.     

The Safe-SADT method for aiding designers to choose and improve dependable architectures for complex automated systems

Dependability evaluation is crucial to controlling the risks associated with system failure, and for this reason, it is one of the fundamental steps in automated system design. However, the dependability evaluation methods that are currently exploited are not appropriate, given the level of complexity of such industrial systems. The ineffectiveness of the existing methods led us to develop and propose the Safe-SADT (structured analysis and design technique) method. Our method allows the explicit formalization of functional interactions, the identification of the characteristic values affecting the dependability of complex systems, the quantification of the reliability, availability, maintainability, and safety (RAMS) parameters of the system's operational architecture, and the validation of that operational architecture in terms of the dependability objectives and constraints set down in the functional requirement specifications (FRS). The results presented in this paper are limited to RAM quantification.     

Formation of Colony Odor in Ponerine Ant Pachycondyla apicalis

The mechanisms operating in the formation and maintenance of colony odor in the ponerine ant Pachycondyla apicalis were studied using radioactive tracers. Using [l-¹⁴C]acetate as a precursor, the de novo biosynthesis and distribution of pentane-extractable lipids within the ant's body were followed. Twenty-four hours after injection, newly synthesized alkanes, alkenes, as well as more polar lipids were found in the postpharyngeal gland, the epicuticle, and internally. Ants that had their mouths blocked with beeswax possessed significantly less radiolabeled lipids (all classes measured) in the postpharyngeal gland but had augmented levels in the internal pool and the epicuticle. Both hydrocarbons and more polar lipids were exchanged between the respective postpharyngeal glands and the epicuticle. The transfer to postpharyngeal glands was highest when both ants had an open mouth or when the recipient ant had an open mouth but the donor's mouth was blocked. This suggests that the transfer to the postpharyngeal gland in this species is by allogrooming and not by trophallaxis. Transfer to the cuticle was low and comparable in all treatments. Behavioral observations during the first 6 hr of the dyadic encounters and in intact colonies confirmed that the ants did not engage in trophallaxis. The level of transfer to the postpharyngeal gland in P. apicalis was significantly lower than in representatives of other Formicidae subfamilies studied so far. We attribute this difference to the evolution of trophallaxis in the higher Formicidae.