Portable machine welding head automatically controls arc

Portable weld tool makes weld repairs out-of-station and on the side opposite the original weld. It provides full automatic control of the arc voltage, current, wire feed, and electrode travel speed in all welding attitudes. The device is readily adaptable to commercially available straight polarity dc weld packs

Modelling of AlAs/GaAs interfacial structures using high-angle annular dark field (HAADF) image simulations

High angle annular dark field (HAADF) image simulations were performed on a series of AlAs/GaAsinterfacial models using the frozen-phonon multislice method. Three general types of models were considered—perfect, vicinal/sawtooth and diffusion. These were chosen to demonstrate how HAADFimage measurements are influenced by different interfacialstructures in the technologically important III–V semiconductor system. For each model, interfacial sharpness was calculated as a function of depth and compared to aberration-corrected HAADF experiments of two types of AlAs/GaAs interfaces. The results show that the sharpness measured from HAADF imaging changes in a complicated manner with thickness for complex interfacialstructures. For vicinal structures, it was revealed that the type of material that the probe projects through first of all has a significant effect on the measured sharpness. An increase in the vicinal angle was also shown to generate a wider interface in the random step model. The Moison diffusion model produced an increase in the interface width with depth which closely matched the experimental results of the AlAs-on-GaAs interface. In contrast, the interface width decreased as a function of depth in the linear diffusion model. Only in the case of the perfect model was it possible to ascertain the underlying structure directly from HAADFimage analysis

The Economic Legacy of Divorced and Separated Women in Old Age

Although progress has been made over the last 20 years, the burden of a low income in old age is still carried by unattached women. Few researchers, however, have examined exactly where the burden of poverty falls within the category of unattached older women or the nature of this poverty. Like any other group of older Canadians, unattached women are not a homogenous population. The category of 'unattached' includes the separated, divorced, widowed and ever single, all of whom face different circumstances in old age because of differences over the life course. Using SLID data we examine income and sources of income from 1993 to 1999 to identify differences among these groups. The findings indicate that the separated and divorced are the poorest of all older unattached women in Canada. A key source of the difference is the growth in private pension incomes.low income; old age; unattached women; SLID

The Economic Legacy of Divorced and Separated Women in Old Age

Although progress has been made over the last 20 years, the burden of a low income in old age is still carried by unattached women. Few researchers, however, have examined exactly where the burden of poverty falls within the category of unattached older women or the nature of this poverty. Like any other group of older Canadians, unattached women are not a homogenous population. The category of "unattached" includes the separated, divorced, widowed and ever single, all of whom face different circumstances in old age because of differences over the life course. Using SLID data we examine income and sources of income from 1993 to 1999 to identify differences among these groups. The findings indicate that the separated and divorced are the poorest of all older unattached women in Canada. A key source of the difference is the growth in private pension incomes.low income; old age; unattached women; SLID

What impact do questionnaire length and monetary incentives have on mailed health psychology survey response?

Objectives: Response rates to health-related surveys are declining. This study tested two strategies to improve the response rate to a health psychology survey mailed through English general practices: (1) sending a shortened questionnaire and (2) offering a monetary incentive to return a completed questionnaire. Design: Randomized controlled trial. Methods: Adults (n = 4,241) aged 45–59 years, from four General Practices in South-East England, were mailed a survey on attitudes towards bowel cancer screening. Using a 2 × 4 factorial design, participants were randomized to receive a ‘short’ (four A4 pages) or a ‘long’ (seven A4 pages) questionnaire, and one of four monetary incentives to return a completed questionnaire – (1) no monetary incentive, (2) £2.50 shop voucher, (3) £5.00 shop voucher, and (4) inclusion in a £250 shop voucher prize draw. Age, gender, and area-level deprivation were obtained from the General Practices. Results: The overall response rate was 41% (n = 1,589). Response to the ‘short’ questionnaire (42%) was not significantly different from the ‘long’ questionnaire (40%). The £2.50 incentive (43%) significantly improved response rates in univariate analyses, and remained significant after controlling for age, gender, area-level deprivation, and questionnaire length. The £5.00 (42%) and £250 prize draw (41%) incentives had no significant impact on response rates compared to no incentive (38%). Conclusions: A small monetary incentive (£2.50) may slightly increase response to a mailed health psychology survey. The length of the questionnaire (four pages vs. seven pages) did not influence response. Although frequently used, entry into a prize draw did not increase response. Achieving representative samples remains a challenge for health psychology

A note on Dolby and Gull on radar time and the twin "paradox"

Recently a suggestion has been made that standard textbook representations of hypersurfaces of simultaneity for the travelling twin in the twin "paradox" are incorrect. This suggestion is false: the standard textbooks are in agreement with a proper understanding of the relativity of simultaneity.Comment: LaTeX, 3 pages, 2 figures. Update: added new section V and updated reference

Persistence and Academic Success in University

We use a unique set of linked administrative data sets to explore the determinants of persistence and academic success in university. The explanatory power of high school grades greatly dominates that of other variables such as university program, gender, and neighbourhood and high school characteristics. Indeed, high school and neighbourhood characteristics, such as average standardized test scores for a high school or average neighbourhood income, have weak links with success in university.university success, high school, neighbourhood.

Willingness-to-Pay for Improved Air Quality in Hamilton-Wentworth: A Choice Experiment

Prepared for Hamilton-Wentworth Air Quality Initiative pursuant to a memorandum of understanding among McMaster University, the Ontario Ministry of Environment and Energy and the Regional Municipality of Hamilton-Wentworth, dated November 5, 1996.

Persistence and Academic Success in University

We use a unique set of linked administrative data sets to explore the determinants of persistence and academic success in university. The explanatory power of high school grades greatly dominates that of other variables such as university program, gender, and neighbourhood and high school characteristics. Indeed, high school and neighbourhood characteristics, such as average standardized test scores for a high school or average neighbourhood income, have weak links with success in university.University Success, High School, Neighbourhood