On some auxiliary mappings generated by nonexpansive and strictly pseudo-contractive mappings

Starting by a finite family of mappings, we define the concept of procedure with Lipschitzian dependence of the coefficients. We give seven concrete examples of such procedures and prove the strong convergence of two viscosity methods.     

Benders decomposition, Lagrangean relaxation and metaheuristic design

Large part of combinatorial optimization research has been devoted to the study of exact methods leading to a number of very diversified solution approaches. Some of those older frameworks can now be revisited in a metaheuristic perspective, as they are quite general frameworks for dealing with optimization problems. In this work, we propose to investigate the possibility of reinterpreting decompositions, with special emphasis on the related Benders and Lagrangean relaxation techniques. We show how these techniques, whose heuristic effectiveness is already testified by a wide literature, can be framed as a “master process that guides and modifies the operations of subordinate heuristics”, i.e., as metaheuristics. Obvious advantages arise from these approaches, first of all the runtime evolution of both upper and lower bounds to the optimal solution cost, thus yielding both a high-quality heuristic solution and a runtime quality certificate of that same solution.     

Testing the structure of multistage stochastic programs

A fixed topology of stages and/or a fixed branching scheme are common assumptions for applications and numerical solution of scenario based multistage stochastic programs. Using contamination technique to test this structure, we extend the results of Dupačová (Contamination for multistage stochastic programs. In: Hušková M, Janžura M (eds) Prague stochastics. Matfyzpress, Praha, pp 91–101, 2006a) to stochastic programs with multistage polyhedral risk objectives. The ideas are exemplified by bond portfolio management problems and complemented by illustrative numerical results.     

Numerical Analysis of Structural Systems Subjected to Non-Gaussian Random Fields

This paper deals with the stochastic response of structures loaded by non-Gaussian random fields. A finite element model is used to describe a cantilever beam assuming both linear and non-linear behavior. The cross-correlated stochastic field is generated by a numerical procedure based on the translation processes theory. The marginal distribution of the load is assumed to be lognormal and the correlation structure is based on the second-order Markov process. The statistical analysis of the results highlights the effects of the involved non-linearity and non-Gaussianity properties on the structures response.     

Clifford Fields and the Relativistic Equation of the Nucleon

A relativistic equation for free fields whichtake their values in the Clifford algebra associatedwith the Minkowski metric is shown to be interpretableas the equation of the nucleon. The internal symmetry group SU(2) arises naturally from theassociative algebra structure of the representationspace. The latter structure can be used to constructcoupling terms consistent with the transformationproperties of the interacting fields; in particular, itallows the familiar couplings of the nucleon field withthe electromagnetic field and with the -mesonfield.     

A critical analysis of the hand and Othmer-Tobias correlations

Carniti, P., Cori, L. and Ragaini, V., 1978. A Critical Analysis of the Hand and Othmer-Tobias Correlations. Fluid Phase Equilibria, 2: 39–47.The Hand (H) and Othmer-Tobias (OT) correlations are extensively analyzed on 83 aqueous and 26 non-aqueous ternary systems. Twenty solutropic systems are also included. 65% and 58% of the systems give a linear correlation coefficient greater than 0.99 for H and OT respectively.An analysis of the sensitivity to systematic or random errors demonstrates the H correlation to be highly insensitive. A remarkable insensitivity, although not completly for some systematic errors, is also demonstrated for the OT correlation. However there is sufficient proof that they are both unsuitable as a check of experimental data, even though they are used for this purpose.The relation, not necessarily linear, derived from the H correlation, log(x₃₂/x₂₂) vs. log(x₃₁/x₁₁) is useful in locating the plait point.     

Thermodynamics of alcohols and monosaccharides in aqueous solutions of biuret at 25°C

The excess enthalpies of ternary aqueous solutions of biuret with four aliphatic alcohols or four isomeric pentoses have been determined by flow microcalorimetry at 25°C. The coefficients of the virial expansion of the excess enthalpies have been evaluated and compared with those already reported for urea and thiourea with the same alcohols and pentoses used here. For biuret-alcohol systems, the cross coefficients are positive and depend on the length and branching of the alkyl chain of the alcohols. On the contrary, they are negative for biuret-pentose systems. Hence, biuret, as urea and thioura, is able to differentiate the behavior of families of solutes characterized by the same functional groups. The results are interpreted in terms of the relative stabilities of the hydration cospheres of predominantly hydrophobic or predominantly hydrophilic cosolutes. However, hypotheses about the hydration cospheres of the saccharides, which are more complex than those used previously, seem to be necessary to rationalize their complete behavior in water.     

Search of ligands for the amyloidogenic protein beta2-microglobulin by capillary electrophoresis and other techniques

Beta2-microglobulin (beta2-m) is a small amyloidogenic protein normally present on the surface of most nucleated cells and responsible for dialysis-related amyloidosis, which represents a severe complication of long-term hemodialysis. A therapeutic approach for this amyloidosis could be based on the stabilization of beta2-m through the binding to a small molecule, and consequent inhibition of protein misfolding and amyloid fibril formation. A few compounds have been described to weakly bind beta2-m, including the drug suramin. The lack of a binding site for nonpolypeptidic ligands on the beta2-m structure makes it difficult for both the identification of functional groups responsible for the binding and the search of hits to be optimized. The characterization of the binding properties of suramin for beta2-m by using three different techniques (surface plasmon resonance, affinity CE (ACE), ultrafiltration) is here described and the results obtained are compared. The common features of the chemical structures of the compounds known to bind the protein led us to select 200 sulfonated/suramin-like molecules from a wider chemical library on the basis of similarity rules, so as to possibly single out some interesting hits and to gain more information on the functional groups involved in the binding. The development of screening methods to test the compounds by using ultrafiltration and ACE is described.     

One-pot preparation and uranyl adsorption properties of hierarchically porous zirconium titanium oxide beads using phase separation processes to vary macropore morphology

A simple and engineering friendly one-step process has been used to prepare zirconium titanium mixed oxide beads with porosity on multiple length scales. In this facile synthesis, the bead diameter and the macroporosity can be conveniently controlled through minor alterations in the synthesis conditions. The precursor solution consisted of poly(acrylonitrile) dissolved in dimethyl sulfoxide to which was added block copolymer Pluronic F127 and metal alkoxides. The millimeter-sized spheres were fabricated with differing macropore dimensions and morphology through dropwise addition of the precursor solution into a gelation bath consisting of water (H(2)O beads) or liquid nitrogen (LN(2) beads). The inorganic beads obtained after calcination (550 °C in air) had surface areas of 140 and 128 m(2) g(-1), respectively, and had varied pore architectures. The H(2)O-derived beads had much larger macropores (5.7 μm) and smaller mesopores (6.3 nm) compared with the LN(2)-derived beads (0.8 μm and 24 nm, respectively). Pluronic F127 was an important addition to the precursor solution, as it resulted in increased surface area, pore volume, and compressive yield point. From nonambient XRD analysis, it was concluded that the zirconium and titanium were homogeneously mixed within the oxide. The beads were analyzed for surface accessibility and adsorption rate by monitoring the uptake of uranyl species from solution. The macropore diameter and morphology greatly impacted surface accessibility. Beads with larger macropores reached adsorption equilibrium much faster than the beads with a more tortuous macropore network.