The Pathmox approach for PLS path modeling: Discovering which constructs differentiate segments

The problem of heterogeneity represents a very important issue in the decision‐making process. Furthermore, it has become common practice in the context of marketing research to assume that different population parameters are possible depending on sociodemographic and psycho‐demographic variables such as age, gender, and social status. In recent decades, numerous approaches have been proposed with the aim of involving heterogeneity in the parameter estimation procedures. In partial least squares path modeling, the common practice consists of achieving a global measurement of the differences arising from heterogeneity. This leaves the analyst with the important task of detecting, a posteriori, which are the causal relationships (ie, path coefficients) that produce changes in the model. This is the case in Pathmox analysis, which solves the heterogeneity problem by building a binary tree to detect those segments of population that cause the heterogeneity. In this article, we propose extending the same Pathmox methodology to asses which particular endogenous equation of the structural model and which path coefficients are responsible of the difference.     

Existence of positive pseudo almost periodic solutions to a class of neutral integral equations

In this work, a new fixed point theorem in partially ordered Banach spaces is established, and then used to prove the existence of positive pseudo almost periodic solutions to a class of neutral integral equations. Our existence theorem extends some recent results due to [E. Ait Dads, P. Cieutat, L. Lhachimi, Positive pseudo almost periodic solutions for some nonlinear infinite delay integral equations, Mathematical and Computer Modelling 49 (2009) 721–739] to a more general class of integral equations.     

TPGS-750-M: a second-generation amphiphile for metal-catalyzed cross-couplings in water at room temperature

An environmentally benign surfactant (TPGS-750-M), a diester composed of racemic α-tocopherol, MPEG-750, and succinic acid, has been designed and readily prepared as an effective nanomicelle-forming species for general use in metal-catalyzed cross-coupling reactions in water. Several "name" reactions, including Heck, Suzuki-Miyaura, Sonogashira, and Negishi-like couplings, have been studied using this technology, as have aminations, C-H activations, and olefin metathesis reactions. Physical data in the form of DLS and cryo-TEM measurements suggest that particle size and shape are key elements in achieving high levels of conversion and, hence, good isolated yields of products. This new amphiphile will soon be commercially available.     

Vibrational properties of polyatomic molecules by quantum chemical methods

Force constants and dipole moment derivatives have been computed for the molecules CH₃ X(X=F, Cl, Br, I) using MO wavefunctions with pseudo-potentials for the interaction between the inner shell and valence electrons. The values obtained at the SCF approximation level from a set of gaussian valence orbitals contracted in double-zeta form and enriched with polarization functions compare well with experimental assignments of force and interaction constants, as well as integrated intensities from infrared data. The transferability of atomic force fields and polar tensors (second derivatives of total energies and first derivatives of dipole moments with respect to atomic displacements in cartesian coordinates) is discussed.     

Bioactive Pectin-Murta (Ugni molinae T.) Seed Extract Films Reinforced with Chitin Fibers

This study investigated the biocomposite pectin films enriched with murta (Ugni molinae T.) seed polyphenolic extract and reinforced by chitin nanofiber. The structural, morphological, mechanical, barrier, colorimetric, and antioxidant activity of films were evaluated. The obtained data clearly demonstrated that the addition of murta seed extract and the high load of chitin nanofibers (50%) provided more cohesive and dense morphology of films and improved the mechanical resistance and water vapor barrier in comparison to the control pectin film. The antioxidant activity ranged between 71% and 86%, depending on the film formulation and concentration of chitin nanofibers. The presented results highlight the potential use of chitin nanofibers and murta seed extract in the pectin matrix to be applied in functional food coatings and packaging, as a sustainable solution.     

Structure and stability of (CuNO) isomers

Quantum-mechanical calculations have been performed on various isomers of the (CuNO)⁺ system. A ²Π ground state is found for the linear CuNO⁺ and CuON⁺ isomers and a ²A′ state for the bent CuNO⁺ and CuON⁺ isomers. Energy calculations indicate that the linear CuNO⁺ structure is the most stable, the bent CuNO⁺ and CuON⁺ and the linear CuON⁺ structures are at 0.86 eV, 0.99 eV and 1.04 eV above this respectively. In the CuNO⁺ → CuON⁺ interconversion between the linear isomers, three transition states are involved, whereas the bent CuNO⁺ isomer is found to be an intermediate species. The isomerization barriers, dissociation energies, equilibrium geometries and vibration frequencies are given for all isomers in their ground and first excited states.     

On the structure of zero finders

Zero finders written in FORTRAN usually impose a false and inconvenient structure on the program. Desirable software and numerical features of a zero finder are discussed. A zero finder with a new structure is presented together with a number of examples that illustrate its flexibility.This work was supported by the Department of Communications, National Research Council and Defense Research Board of the government of Canada and by the University of Waterloo.     

Proprietes electroniques et electrogalvaniques du sulfure d'argent α domaine d'existence

The study of electronic and electrogalvanic properties of α silver sulphide has been performed on samples whose non-stoichiometry is controlled by annealing under sulphur pressure or by coulometric titration with the cell Ag/AgI/Ag_2+εS/Pt.The data obtained lead to the adoption of an electronic model according to which the Frenkel defects are completly ionised. The homogeneity range has been drawn between 193° and 550°C. It extends to both sides of the stoichiometric composition.     

An experimental and theoretical study of dipole moments of N-alkyl-1,3-bis-(p-chlorophenyl)triazenes and 1-(3,4-dimethyl-5-isoxazolyl)-3-aryltriazenes

The dielectric constants, densities, and the refractive indices of dilute benzene solutions have been used to obtain the experimental dipole moments of 1,3-diphenyltriazene (1a), 1,3-diphenyl-3-methyltriazene (Ib), 1,3-bis(p-chlorophenyl)triazene (IIa), its N-alkyi derivatives (IIb-IIg), and 1-(3,4-dimethyl-5-isoxazolyl)-3-phenyltriazene (IIIb) and its N-methyl derivative (IIIc). The results show that the dipole moment of IIa is increased by an increment of about 0.77 D (average value for methyl, ethyl, n-propyl, allyl, and benzyl) on N-alkyl substitution. The increment for the n-butyl group is Δμ = 1.19 D. Some of the experimental values are compared with those from PPP and CNDO/2 calculations.     

Proprietes electroniques et electrogalvaniques du tellurure d'argent α domaine d'existence

A study of the electronic and electrogalvanic properties of α silver telluride has been performed on samples whose non-stoiehiometry has been determined by coulometric titration with the cell Ag/AgI/Ag₂Te/Pt. The data lead to the adoption of a model of Frenkel defects on the silver sublattice that are fully ionised. The homogeneity range is reported from 162 to 508°C: it extends essentially on the tellurium side of the stoichiometric composition. The free energies of formation of the α and β forms of the tellurides whose compositions are near Ag_1,6Te, Ag_1,9Te and Ag_2,0Te have been determined between 23°C and 360°C.