Rational representations and robust stabilization in the behavioral framework

In this paper, we study the problem of robust stabilization for linear differential systems in the behavioral framework. We study the existence of controllers that regularly stabilize all plants in a given neighborhood around a certain nominal plant. We call such controllers robustly stabilizing controllers. This problem was studied in the behavioral framework by Trentelman, H.L et al. In contrast to their work, however, in the present paper, we study the problem considering neighborhoods that are defined entirely representation free. These neighborhoods are induced by different kinds of concepts of distance between behaviors. As one of our main results we obtain that a given controller regularly stabilizes all plants in one of these neighborhoods if and only if it regularly stabilizes all plants in all of the other neighborhoods. Copyright © 2014 John Wiley & Sons, Ltd.     

Aging does not affect gray matter asymmetry.

Previous research has shown that asymmetry of brain activity is decreased in older adults. This study investigates whether cortical gray matter asymmetry also shows age-related differences, and whether gray matter asymmetry differs between cognitively stable persons and persons who have shown profound age-related declines in cognitive functioning. In addition, we have examined whether prodromal dementia affects the study outcome. The gray matter volumes of seven prefrontal and temporal regions of interest were delineated on T1-weighted MRI scans in 70 adults aged between 52 and 84 years. Statistical analyses were conducted with and without participants who developed dementia within 6 years after the MRI scan session. It was found that asymmetry did not differ over the age range of 52–84 years of age. This result did not change when data from participants who were diagnosed with dementia within 6 years after MRI assessment were excluded from the analysis. In addition, no gray matter asymmetry differences were found between cognitively stable participants and participants who showed cognitive decline. We conclude that alterations in gray matter asymmetry may not be part of the healthy aging process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Occupational stress in Canadian universities: A national survey.

Stress surveys in U.K. and Australian universities demonstrated high occupational stress levels among faculty. This study investigated whether the same occupational stressors and stress outcomes applied at Canadian universities. Randomly selected staff (n = 1440) from 56 universities completed a Web-based questionnaire. The response rate 27%, was similar to those in the U.K. and Australian studies, as were most of the results. With respect to strain, 13% of the respondents reported high psychological distress and 22% reported elevated physical health symptoms. Less secure employment status and work-life imbalance strongly predicted job dissatisfaction; work-life imbalance strongly predicted increased psychological distress. Overall study participants were satisfied with their jobs and emotionally committed to their institutions. These results warrant consideration of contemporary academic work by both academic staff associations and university administrations with respect to the implementation of changes in policies and procedures that might lead to reductions in work-related stress and strain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantifying Microwear on Experimental Mistassini Quartzite Scrapers: Preliminary Results of Exploratory Research Using LSCM and Scale‐Sensitive Fractal Analysis

Although previous use‐wear studies involving quartz and quartzite have been undertaken by archaeologists, these are comparatively few in number. Moreover, there has been relatively little effort to quantify use‐wear on stone tools made from quartzite. The purpose of this article is to determine the effectiveness of a measurement system, laser scanning confocal microscopy (LSCM), to document the surface roughness or texture of experimental Mistassini quartzite scrapers used on two different contact materials (fresh and dry deer hide). As in previous studies using LSCM on chert, flint, and obsidian, this exploratory study incorporates a mathematical algorithm that permits the discrimination of surface roughness based on comparisons at multiple scales. Specifically, we employ measures of relative area (RelA) coupled with the F‐test to discriminate used from unused stone tool surfaces, as well as surfaces of quartzite scrapers used on dry and fresh deer hide. Our results further demonstrate the effect of raw material variation on use‐wear formation and its documentation using LSCM and RelA. SCANNING 35:28‐39, 2013. © 2012 Wiley Periodicals, Inc.     

Global Trends in Computing Accreditation

As computing accreditation increases, three trends are emerging: clarified definitions of disciplines, a unified approach to accreditation, and a focus on graduates' long-term competencies.     

Non‐stoichiometry in Oxide Thin Films: A Chemical Capacitance Study of the Praseodymium‐Cerium Oxide System

While the properties of functional oxide thin films often depend strongly on their oxygen stoichiometry, there have been few ways to extract this information reliably and in situ. In this work, the derivation of the oxygen non‐stoichiometry of dense Pr_0.1Ce_0.9O_2?δ thin films from an analysis of chemical capacitance obtained by impedance spectroscopy is described. Measurements are performed on electrochemical cells of the form Pr_0.1Ce_0.9O_2?δ/Y_0.16Zr_0.84O_1.92/Pr_0.1Ce_0.9O_2?δ over the temperature range of 450 to 800 °C and oxygen partial pressure range of 10^?5 to 1 atm O₂. With the aid of a defect equilibria model, approximations relate chemical capacitance directly to non‐stoichiometry, without need for fitting parameters. The calculated non‐stoichiometry allows extraction of the thermodynamic constants defining defect generation. General agreement of these constants with bulk values derived by thermogravimetric analysis is found, thereby confirming the suitability of this technique for measuring oxygen non‐stoichiometry of thin oxide films. Potential sources of error observed in earlier chemical capacitance studies on perovskite structured oxide films are also discussed.     

Trifluoropropyl Halophenyl Substituted Silicone Copolymers—A New Class of Wide Temperature Range Lubricants

Chlorophenyl substituted silicones have better lubricating properties than lightly phenylated methyl silicones with similar physical properties. The best load-carrying and anti-wear properties are obtained with fluorosilicones at some loss in low-temperature properties. This paper describes a new class of silicone copolymers containing both trifluoropropyl and halophenyl substitution which can cover a temperature span of ?100 F to 650 F. Data are included showing that this combination improves both low and heavy load anti-wear properties for steel. Physical, friction and wear, and stability data are given describing these properties as a function of the type, and amount of halogen on the phenyl as well as with varying ratios of trifluoropropyl to halophenyl substitution. Differences in lubricating performances and mechanisms for various halogenated groups are discussed to explain the improvements noted for the combination of halophenyl with trifluoropropyl groups. Final formulation of a potential wide temperature range hydraulic fluid is described.