Mentoring students and professionals with disabilities.

Mentoring can have a significant positive impact on the lives of individuals. People with disabilities seeking to locate mentors face a variety of potential challenges and benefits. This article addresses mentoring-related issues faced by professionals with disabilities. The article presents a model of mentoring and discusses the difficulties faced by individuals with disabilities in locating mentors. It describes the negative impact of the lack of available mentors upon the educational and vocational development of people with disabilities. It offers effective strategies aimed at enhancing mentoring relationships with people with disabilities, including macrofocused strategies capable of enhancing the effectiveness of disability-related mentoring programs and microfocused strategies useful in developing quality mentoring relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Further Developments in the Photography of Two-Phase Gas-Liquid Flow

Equipment and techniques for photography of two-phase flow are described. The application of photography to the determination of flow patterns, to the study of climbing and falling liquid film systems and to the study of two-phase flow accompanied by vapour generation, is discussed. The work has included the use of X-radiography, the use of microscopic techniques in studying the interface of a falling film, the use of axially directed photography in evaluating climbing film flow and the use of photography in studying droplet mass transfer.     

On multivariate order statistics. Application to ranked set sampling

Two new concepts of order statistics for multivariate samples are introduced. In one of the versions it turns out that not every multivariate order statistic is present in every sample. These order statistics have application in multivariate ranked set sampling and can be used to generate broad classes of multivariate densities in the sense of Jones. In this case the likelihood for the sample values and their corresponding ranks can be calculated based on the conditional density of a multivariate order statistics given its sample value, and such that its integral gives the probability for the multivariate order statistics under discussion to be observed. An alternative version of multivariate order statistics is also introduced, for which multivariate order statistics are always well defined and expressions for their marginal densities are derived. Since these multivariate order statistics are tailor made for multivariate ranked set sampling, their densities allow for parameter inference based on ranked set sampling. Some simulations show that both multivariate order statistics densities can be used with advantage with respect to simple random sampling.     

Conference Reviews

Abstract

The desire to teach in a way that acknowledges our position in the world as global citizens faces several challenges, many of which are global in nature. We identify three of these. First, there is the split between “modern” and “traditional” that can be found in a wide range of institutional and historical practices the world over. Second, there is the problem of language which has embedded within it certain historical presumptions. Third, there is the hesitancy in studio teaching to address issues that allow students to see themselves as actors in global history. What we advocate is a global critique of anti-global practices.     

Extraction and characterisation of protein fractions from five insect species

Tenebrio molitor, Zophobas morio, Alphitobius diaperinus, Acheta domesticus and Blaptica dubia were evaluated for their potential as a future protein source. Crude protein content ranged from 19% to 22% (Dumas analysis). Essential amino acid levels in all insect species were comparable with soybean proteins, but lower than for casein. After aqueous extraction, next to a fat fraction, a supernatant, pellet, and residue were obtained, containing 17–23%, 33–39%, 31–47% of total protein, respectively. At 3% (w/v), supernatant fractions did not form stable foams and gels at pH 3, 5, 7, and 10, except for gelation for A. domesticus at pH 7. At 30% w/v, gels at pH 7 and pH 10 were formed, but not at pH 3 and pH 5. In conclusion, the insect species studied have potential to be used in foods due to: (1) absolute protein levels; (2) protein quality; (3) ability to form gels.     

Work stressors, role-based performance, and the moderating influence of organizational support.

As a test of the 2-dimensional model of work stressors, the present study proposed differential relationships between challenge stressors and hindrance stressors and role-based performance, which were expected to be moderated by organizational support. In a sample of 215 employees across 61 offices of a state agency, the authors obtained a positive relationship between challenge stressors and role-based performance and a negative relationship between hindrance stressors and role-based performance. In addition, organizational support moderated the relationship between challenge stressors and role-based performance but did not moderate the relationship between hindrance stressors and role-based performance. This suggests that organizations would benefit from increasing challenges in the workplace as long as they are supportive of employees and removing hindrances. Further implications for organizational theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polymerization of epoxy resins initiated by metal complexes

BACKGROUND: Processing parameters and material properties of epoxy resins can be vastly influenced by choice of curing agent. In this work, metal complexes were investigated as initiators for anionic and cationic epoxide polymerization. Systems for thermally induced and electron beam‐induced curing are described. RESULTS: Zinc or cobalt imidazole complexes of the type [M(imidazole)₂(anion)₂] are efficient initiators for anionic polymerization of glycidyl‐based epoxy resins. The complexes can be employed to prepare tailored resin systems ranging from fast curing systems at slightly elevated temperatures to systems with very high thermal latencies curable at temperatures far above 150 °C. Silver complexes [Ag(L)_n]SbF₆ (L = crown ether or alkene) are highly efficient initiators for cationic curing and low initiator contents of around 1% are sufficient to reach high degrees of crosslinking. The complexes are excellent initiators for both thermally induced and electron beam‐induced polymerizations. CONCLUSION: Metal complexes are powerful initiators for the homopolymerization of epoxy resins and can be designed not only for anionic and cationic polymerization but also for thermal and radiation curing. Based on this study and additional work, a library can be compiled which allows retrieval of optimized metal–ligand–anion combinations and adjustment of the initiators to the respective processing and material demands. Copyright © 2009 Society of Chemical Industry     

Reductive dechlorination of 1,1,2,2-tetrachloroethane

Products of the transformation of organic pollutants in the environment are often predicted based on the structure of the parent compounds. In some cases, however, multiple products may result from the same reaction pathway. In this study, the reduction of 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) is investigated both experimentally and computationally. Experimental results and data available in the literature reveal that the ratio of Z-1,2-dichloroethylene (Z-DCE) to E-1,2-dichloroethylene (E-DCE) produced from the reductive beta-elimination of 1,1,2,2-TeCA is approximately 2:1, and this ratio is independent of the reductant used. The exception is iron metal, which results in a ratio of 4.5:1. Computational results reveal that the 1,2,2-trichloroethyl radicals (1,1,2-TCA*) formed upon the transfer of the first electron are nearly isoenergetic and are in rapid equilibrium. Thus, the conformer population of the 1,1,2,2-TeCA does not dictate the product distribution. Using Marcus theory, it is demonstrated that the Z:E ratio of 2:1 reflects the relative rates of the two possible electron transfer steps to the two radical conformers. Further analysis of the thermochemistry of the reaction reveals that this ratio of rate constants should be essentially independent of the thermodynamic driving force, which is consistent with the experimental results. The different observed product distribution when iron metal is the reductant is hypothesized to result from an organometallic intermediate. The reduction of the 1,1,2,2-TeCA is an overall two-electron process, but the fact that the radicals equilibrate at a rate more rapid than the transfer of the second electron suggests that reductants employed act as decoupled single electron-transfer agents.     

An integrated microfabricated cell sorter

We have developed an integrated microfabricated cell sorter using multilayer soft lithography. This integrated cell sorter is incorporated with various microfluidic functionalities, including peristaltic pumps, dampers, switch valves, and input and output wells, to perform cell sorting in a coordinated and automated fashion. The active volume of an actuated valve on this integrated cell sorter can be as small as 1 pL, and the volume of optical interrogation is approximately 100 fL. Different algorithms of cell manipulation, including cell trapping, were implemented in these devices. We have also demonstrated sorting and recovery of Escherichia coli cells on the chip.     

Phase-stepping interferometry: methods for reducing errors caused by camera nonlinearities

Phase errors that arise in phase-stepping interferometry are discussed. Investigations were performed by use of a Twyman-Green interferometer equipped with a compensation plate with a variable and servo-controlled tilt angle. With this instrument, phase-stepping errors can be reduced to a negligible level. There are, however, phase errors that are caused by camera nonlinearities. Two methods for minimizing these errors are presented. The first method is based on the simple idea that the interference intensity at the output of a two-beam interferometer has an exact cosine shape. The camera signals were monitored as a function of the tilt angle of the compensation plate, and the deviation from the cosine form was used to produce a correction. The second method is based on the idea that, under specific conditions, errors of an average of two phase measurements may compensate for each other. Numerical calculations were performed and give evidence of this hypothesis. Each method, the signal-correction and the averaging method, drastically reduces errors in evaluation of phases. The combination of both methods is a powerful tool that allows precise phase data to be obtained with an uncertainty, in the range lambda/2000 approximately 0.3 nm, that is caused mainly by signal noise.