Statistical Analysis for Decision Making

In this article we consider a generalization of the univariate g-and-h distribution to the multivariate situation with the aim of providing a flexible family of multivariate distributions that incorporate skewness and kurtosis. The approach is to modify the underlying random variables and their quantiles, directly giving rise to a family of distributions in which the quantiles rather than the densities are the foci of attention. Using the ideas of multivariate quantiles, we show how to fit multivariate data to our multivariate g-and-h distribution. This provides a more flexible family than the skew-normal and skew-elliptical distributions when quantiles are of principal interest. Unlike those families, the distribution of quadratic forms from the multivariate g-and-h distribution depends on the underlying skewness. We illustrate our methods on Australian athletes data, as well as on some wind speed data from the northwest Pacific.     

Wave interactions and wave-structure scattering in nonlinear patterned waveguides

The nonlinear interactions between discrete optical solitons that propagate in different regimes of diffraction, and the nonlinear scattering of dispersive waves by local optical potentials, were studied experimentally. It is well known in electromagnetism that when linear coherent waves meet they interfere without interactions. Linear waves also scatter through local optical structures without exchanging any power with guided and anti-guided modes of these structures. When a focusing Kerr nonlinearity is present, linearly inhibited phenomena, which break these rules, are shown to exist. Our studies were performed with Silica glass and semiconductor AlGaAs nonlinear planar modulated waveguides, excited by ultra-short pulses in the near infrared spectral regime.     

Fuel cell techno-personal milestones 1984–2006

This paper is based on my award acceptance talk on the occasion of receiving the Grove Medal for Fuel Cell Science and Technology, at the 2006 Grove meeting in Torino, Italy. I chose to name the talk: “Fuel Cell Techno-Personal Milestones 1984–2006”, trying to reflect on important milestones in the history of the science and technology of hydrogen/air and methanol/air polymer electrolyte fuel cells, in which I was fortunate to be involved for over 20 years.     

Effect of inorganic constituents on chemical oxygen demand—I. Bromides are unneutralizable by mercuric sulfate complexation

Chemical oxygen demand (COD) assays are widely used for the estimation of the organic carbon content of water and wastewater. The procedure is subject to interference by free halogen ions, the oxidation of which creates artificially high COD values. As part of an investigation of the interferences involved in the COD determination of chemical industries wastewaters, we found that mercuric sulfate complexation, the standard procedure for neutralizing the halogen effects, is suitable for chlorides but is not applicable to bromides. This observation is true both in the presence or absence of chloride or ammonia. Care should therefore be exercised in the interpretation of COD data for bromide-containing samples.     

Differentiating multiple relationships from multiple dimensions of involvement: Therapeutic space at the interface of client, therapist, and society.

This article focuses on redirecting current thinking from multiple relationships to the multiple dimensions of our involvements with clients. Given that people's readiness for human involvement is both desirable and unavoidable, recognizing and managing these multiple dimensions of involvement is at the heart of professional interactions. A triangular space, formed at the intersection of societal, therapist and client features, forms the framework in which therapeutic work occurs. In practice, a balance should be maintained within and among five principles of clinical and ethical practice. These are beneficence, respect for client autonomy, self-awareness, self-interest, and openness to objective input. An applied section considers the sources of imbalance in the proper management of the multiple dimensions of therapists' involvements in the psychotherapeutic relationship via a brief consideration of two case situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Peroxide Formation in a Zero-Gap Chlor-Alkali Cell with an Oxygen-Depolarized Cathode

The effects of various factors on the undesired generation of hydrogen peroxide in a zero-gap oxygen-depolarized chlor-alkali cell employing carbon-supported platinum catalysts were studied. The rate of peroxide generation was found to decrease with platinum loading and increase with current density. The quantity of peroxide generated also increased with electrolysis time, and reached a steady state value after a few 100 h of cell operation at 10 kA m⁻². The steady-state peroxide to hydroxide molar ratio was found to increase with brine concentration. This phenomenon is believed to originate from a decrease of water activity at the reaction site that accompanies the brine concentration increase. No correlation between chloride crossover and the concentration of peroxide generated was detected. It is postulated that carbon particles are predominantly responsible for the partial oxygen reduction and that their contribution increases with electrolysis time as a result of processes that render the carbon surface more hydrophilic.     

Phosphate solubility tests—interference of some accessory minerals

Solubilities of apatites isolated from random samples of Israeli phosphates were determined in citric acid, formic acid and neutral ammonium citrate. Minerals normally associated with the apatites in rock phosphates were then added and the solubility tests repeated. Calcite markedly reduced the apparent solubility in the three solvents but gypsum interfered only in the case of neutral ammonium citrate. The accepted solubility tests therefore favour phosphates containing inert accessory minerals such as quartz and do not reflect the solubility of apatite when it is associated with calcite. A method based on determining the solubility of apatite instead of rock phosphate is suggested.     

A panel of stress-responsive luminous bacteria for the detection of selected classes of toxicants

A panel of bacteria, each genetically engineered to respond by increased luminescence to a different type of environmental stress, is presented. Members of the panel were shown to be sensitive to several groups of chemicals including phenols, halomethanes and several oxidants. The increase in light emission depended upon toxicant concentration and could, thus, be used to calculate a characteristic value, EC₂₀₀, designating the sample concentration causing a two-fold luminescence induction. In almost all cases, EC₂₀₀ values were lower than the corresponding Microtox™ EC₅₀ values, indicating a generally higher sensitivity. One of the panel members, DPD2794, a designated DNA-damage sensor, responded within 2 h to the presence of genotoxicants, including metabolically activated nitropropane. It is suggested that these or similarly constructed strains can be used for the rapid and sensitive detection of potentially toxic and genotoxic pollutants and that the concept of genetically engineering a panel of microbial toxicity sensors can readily be implemented for environmental monitoring.     

Effect of inorganic constituents on chemical oxygen demand—II. Organic carbon to halogen ratios determine halogen interference

The dependency of free halogen ion oxidation in chemical oxygen demand (COD) assays on the organic content of the sample was investigated. Halogen interference was reduced at increasing glucose or potassium hydrogen phthalate concentration; in each case, a threshold ratio of organic matter to halogen existed, above which halogen oxidation was masked. This ratio depended upon the presence of mercuric sulfate in the case of chloride but not of bromide. It was also affected by the ease of oxidation of both the organic molecule and the halogen ion, as well as by their actual COD. Thus, bromide oxidation was more difficult to prevent than that of chloride, and phthalate exerted a stronger masking effect than glucose.