The Systems Approach in an Information Society: A Reconsideration

An information society is one in which informational (or interactional) as opposed to material entities represent the dominant form of social and economic transaction. This paper argues that in such an information-rich environment, the conventional view of the systems approach may no longer be relevant, and may in fact be a serious barrier to the development and implementation of creative management technologies. We present an alternative perspective on the systems approach that emphasizes the primacy of informational concepts as opposed to the primacy of matter/energy concepts. This alternative focuses on interactions, on the logic of change, on circular causality, and on multiple concepts of time. There are important implications for organizational design, managerial control and information systems.     

Lifting,superadditivity, mixed integer rounding and single node flow sets revisited

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure combining mixed integer rounding with lifting for the development of strong valid inequalities for knapsack and single node flow sets. Our hope is that the latter can be used in practice to generate cutting planes for mixed integer programs. The survey contains essentially two parts. In the first we present lifting in a very general way, emphasizing superadditive lifting which allows one to lift simultaneously different sets of variables. In the second, our procedure for generating strong valid inequalities consists of reduction to a knapsack set with a single continuous variable, construction of a mixed integer rounding inequality, and superadditive lifting. It is applied to several generalizations of the 0–1 single node flow set. This paper appeared in 4OR, 1, 173–208 (2003). The first author is supported by the FNRS as a chercheur qualifié. This paper presents research results of the Belgian Program on Interuniversity Poles of Attraction initiated by the Belgian State, Prime Minister’s Office, Science Policy Programming. The scientific responsibility is assumed by the authors.     

The 0-1 Knapsack problem with a single continuous variable

Specifically we investigate the polyhedral structure of the knapsack problem with a single continuous variable, called the mixed 0-1 knapsack problem. First different classes of facet-defining inequalities are derived based on restriction and lifting. The order of lifting, particularly of the continuous variable, plays an important role. Secondly we show that the flow cover inequalities derived for the single node flow set, consisting of arc flows into and out of a single node with binary variable lower and upper bounds on each arc, can be obtained from valid inequalities for the mixed 0-1 knapsack problem. Thus the separation heuristic we derive for mixed knapsack sets can also be used to derive cuts for more general mixed 0-1 constraints. Initial computational results on a variety of problems are presented. Received May 22, 1997 / Revised version received December 22, 1997 Published online November 24, 1998     

Characterization of magnetic labels for bioassays

Magnetic nanoparticles differing by their size have been synthesized to use them for multiparametric testing, based on their differing magnetic properties. The nanoparticle has two essential roles: to act as a probe owing to its specific magnetic properties and to carry on its surface precursor groups for the covalent coupling of biological recognition molecules, such as antibodies, nucleic acids. A totally unique, newly patented, method has been used to characterize magnetic signatures using the MIAplex technology. The MIAplex reader, developed by Magnisense, measures the non-linear response of the magnetic labels when they are exposed to a multi-frequency alternating magnetic field. This specific signature based on d²B(H)/dH² was correlated to other more conventional magnetic detection methods (superconducting quantum interference devices (SQUID) and Mössbauer).     

Intrinsic aging and effective viscosity in the slow dynamics of a soft glass with tunable elasticity

We investigate by rheology and light scattering the influence of the elastic modulus, G0, on the slow dynamics and the aging of a soft glass. We show that the slow dynamics and the aging can be entirely described by the evolution of an effective viscosity, eta(eff), defined as the characteristic time measured in a stress relaxation experiment times G0. At all times, eta(eff) is found to be independent of G0, of elastic perturbations, and of the rate at which the sample is quenched in the glassy phase. We propose a simple model that links eta(eff) to the internal stress built up at the fluid-to-solid transition.     

Synthesis of (Ca,Ce,Ce)2Ti2O7: a pyrochlore with mixed-valence cerium

Pyrochlore with mixed-valence Ce was synthesized by firing and annealing Ce(NO₃)₄, TiO₂, and Ca(OH)₂ with a stoichiometry of CaCeTi₂O₇ at 1300 °C. The product contains Ce-pyrochlore, Ce-rich perovskite, CeO₂ (cerianite), and minor CaO. Electron energy-loss spectroscopy (EELS) revealed both Ce⁴⁺ and Ce³⁺ in the Ce-pyrochlore with a Ce⁴⁺ to total Ce (Ce⁴⁺/ΣCe) of 0.80 giving . Cerium in the perovskite and cerianite is dominated by Ce³⁺ and Ce⁴⁺, respectively. High-resolution transmission electron microscope (HRTEM) images show that the boundary between Ce-pyrochlore and Ce-rich perovskite is semi-coherently bonded. The orientational relationship between the neighboring Ce-pyrochlore and Ce-rich perovskite is not random. Ce-pyrochlore (CaCeTi₂O₇) is a chemical analogue for CaPuTi₂O₇, which is a proposed ceramic waste form for deposition of excess weapons-usable Pu in geological repositories. It is postulated, based on the presence of Ce³⁺ in the Ce-pyrochlore, that neutron poisons such as Gd can be incorporated into the CaPuTi₂O₇ phase.     

The electrooxidation of methanol and related compounds at ruthenium dioxide-coated electrodes

The underlying metal was observed to corrode when a ruthenium dioxide-coated titanium electrode was anodized in an aqueous methanol solution. With a similarly coated platinum electrode peaks were observed on the voltammogram below 1.0 V which were attributed to methanol oxidation on the underlying metal. This effect was more pronounced when the electrode was subjected during cycling to potentials close to 0 V. Rapid oxidation of methanol on RuO₂ was observed at potentials above 1.0 V, the rate at a given potential increasing in an approximately linear manner with increasing alcohol concentration. The rate of reaction also increased with increasing temperature and increasing surface roughness. Tafel slope values were rather high (>100 mV decade^?1) and a mechanism involving anodically generated species such as OH_ads was proposed to account for these results. The variation of activity with pH was similar to that reported earlier for oxygen evolution at these anodes and this was again explained in terms of partial deactivation of the surface due to a combination of proton loss and phosphate ion adsorption at intermediate pH values. The release of carbon dioxide from aqueous solutions of higher alcohols at 25°C confirmed the high oxidizing power of RuO₂ anodes.     

Coordination Compounds of Schiff-Base Ligands Derived from Diaminomaleonitrile (DMN): Mononuclear, Dinuclear, and Macrocyclic Derivatives

Copper(II) and V(IV)O complexes of an open chain (1:2) Schiff-base ligand (H(2)L1), derived by the template condensation of diaminomaleonitrile (DMN) and salicylaldehyde, and dicopper(II) complexes of (2:2) macrocyclic Schiff-base ligands derived by template condensation of diformylphenols and diaminomaleonitrile, have been synthesized and studied. Structures have been established for the first time for mononuclear Cu(II) and V(IV)O derivatives of the open chain ligand H(2)L1 (1:2), a dinuclear macrocyclic Cu(II) complex derived from a 2:2 macrocyclic ligand (H(2)M1), and the half-condensed 1:1 salicylaldehyde ligand (H(2)L2). [Cu(L1)] (1) (L1 = C(18)H(10)N(4)O(2)) crystallized in the monoclinic system, space group P2(1)/n (No. 14), with a = 11.753(6) ?, b = 7.708(5) ?, c = 16.820(1) ?, and Z = 4. [VO(L1)(DMSO] (2) crystallized in the orthorhombic system, space group Pbca (No. 61), with a = 22.534(9) ?, b = 23.31(1) ?, c = 7.694(5) ?, and Z = 8. H(2)L2 (C(18)H(8)N(4)O) (3) crystallized in the monoclinic system, space group P2(1)/c (No. 14), with a = 13.004(6) ?, b = 11.441(7) ?, c = 7.030(4) ?, and Z = 4. [Cu(2)(M3)](CH(3)COCH(3)) (4) (M3 = C(32)H(24)N(8)O(4)) crystallized in the monoclinic system, space group C2/c (No. 15), with a = 38.33(2) ?, b = 8.059(4) ?, c = 22.67(2) ?, and Z = 8. [Cu(L3)(DMSO)] (5) (L3 = C(20)H(14)N(2)O(4)) crystallized in the triclinic system, space group P&onemacr; (No. 2), with a = 10.236(4) ?, b = 13.514(4) ?, c = 9.655(4) ?, and Z = 2. 4 results from the unique addition of two acetone molecules to two imine sites in [Cu(2)(M1)](ClO(4))(2) (M1 = 2:2 macrocyclic ligand derived from template condensation of DMN and 2,6-diformyl-4-methylphenol). 4 has extremely small Cu-OPh-Cu bridge angles (92.0, 92.8 degrees ), well below the expected lower limit for antiferromagnetic behavior, but is still antiferromagnetically coupled (-2J = 25.2 cm(-)(1)). This behavior is associated with a possible antiferromagnetic exchange term that involves the conjugated framework of the macrocyclic ligand itself. The ligand L3 in 5 results from hydrolysis of M1 on recrystallization of [Cu(2)(M1)](ClO(4))(2) from undried dimethyl sulfoxide.     

Synthesis of macrocyclic ligands containing the indole ring system

2,7-Diformyl-3-methyl-4,6-dimethoxyindole (6) has been synthesized and converted by metal template reactions into the macrocyclic complexes (10–12).