Hypotheses Testing for Error-in-Variables Models

In this paper, hypotheses testing based on a corrected score function are considered. Five different testing statistics are proposed and their asymptotic distributions are investigated. It is shown that the statistics are asymptotically distributed according to the chisquare distribution or can be written as a linear combination of chisquare random variables with one degree of freedom. A small scale numerical Monte Carlo study is presented in order to compare the empirical size and power of the proposed tests. A comparative calibration example is used to illustrate the results obtained.     

Immobilized ruthenium complexes and aspects of their reactivity

Methodologies for the immobilization and characterization of ruthenium complexes into/onto functionalized silica gel, zeolites, polymers, dendrimers, sol–gel, nano and microparticles are described. The corresponding spectroscopic, electrochemical, and photochemical properties as well as chemical reactivities are used for their characterization and study. Comparison between the reactivities of immobilized and in solution species is presented. Some biological applications are also described.     

Unbounded solutions of BVP for second order ODE with p-Laplacian on the half line

By applying the Leggett-Williams fixed point theorem in a suitably constructed cone, we obtain the existence of at least three unbounded positive solutions for a boundary value problem on the half line. Our result improves and complements some of the work in the literature.     

Antimony as a traffic-related element in size-fractionated road dust samples collected in Buenos Aires

The growing interest of public opinion in environmental problems conducted us to investigate the levels of a toxic traffic-related element such antimony in 19 size-fractionated street dust samples. Samples were collected in the megacity of Buenos Aires during two months at 19 sites with different urban characteristics and traffic profile. Samples were sieved in four fractions (F1 < 37 µm, F2: 37-55 µm, F3: 55-75 µm and F4: 55-100 µm) before elemental analysis. A mixture of aqua regia and hydrofluoric acid was used to digest all samples. Antimony concentrations were quantified by inductively coupled plasma optical emission spectrometry (ICP OES) or flow injection hydride generation-atomic absorption spectrometry (FI-HG-AAS).Twenty four out of 73 sub-samples analyzed showed Sb levels < 0.05 µg g^− 1; in the rest of the samples mean Sb concentrations varied from 1.4 to 20.4 µg g^− 1. Maximum and minimum concentrations (in µg g^− 1) found in individual samples in the four fractions were: Fraction 1, < 0.05-20.4; Fraction 2, < 0.05-18.4; Fraction 3, < 0.05-6.3; Fraction 4, < 0.05-7.7.Antimony was found to be enriched in the smallest size fraction of road dust, with mean enrichment factors varying between 27 (F3) and 272 (F1). Concentrations of Sb were correlated with those of other traffic-related elements such as Cu and Pb and higher levels were found in areas with medium and high traffic densities.