Reliability achievement in high technology space systems

The production of failure-free hardware is discussed. The elements required to achieve such hardware are: technical expertise to design, analyze, and fully understand the design; use of high reliability parts and materials control in the manufacturing process; and testing to understand the system and weed out defects. The durability of the Hughes family of satellites is highlighted

Noncommutative Solitons: Moduli Spaces, Quantization, Finite Theta Effects and Stability

We find the N-soliton solution at infinite theta, as well as the metric on the moduli space corresponding to spatial displacements of the solitons. We use a perturbative expansion to incorporate the leading 1/theta corrections, and find an effective short range attraction between solitons. We study the stability of various solutions. We discuss the finite theta corrections to scattering, and find metastable orbits. Upon quantization of the two-soliton moduli space, for any finite theta, we find an s-wave bound state.Comment: Second revision: Discussions of translation zero-modes in section 4 and scales in section 5 improved; web addresses of movies changed. First revision: Section 6 is rewritten (thanks to M. Headrick for pointing out a mistake in the original version); some references and acknowledgements added. 21 pages, JHEP style, Hypertex, 1 figure, 3 MPEG's at: http://www.physto.se/~unge/traj1.mpg http://www.physto.se/~unge/traj2.mpg http://www.physto.se/~unge/traj3.mp

“Not Being Able to Talk Was Horrid”: A Descriptive, Correlational Study of Communication During Mechanical Ventilation

Objectives: The purpose of this study was to describe the patient experience of communication during mechanical ventilation. Research methodology: This descriptive study is a secondary analysis of data collected to study the relationship between sedation and the MV patients’ recall of the ICU. Interviews, conducted after extubation, included the Intensive Care Experience Questionnaire. Data were analysed with Spearman correlation coefficients (rs) and content analysis. Setting: Participants were recruited from a medical-surgical intensive care unit in the Midwest United States. Results: Participants (n = 31) with a mean age of 65 ± 11.9 were on the ventilator a median of 5 days. Inability to communicate needs was associated with helplessness (rs = .43). While perceived lack of information received was associated with not feeling in control (rs = 41) and helplessness (rs = 41). Ineffective communication impacted negatively on satisfaction with care. Participants expressed frustration with failed communication and a lack of information received. They believed receipt of information helped them cope and desired a better system of communication during mechanical ventilation. Conclusion: Communication effectiveness impacts patients’ sense of safety and well-being during mechanical ventilation. Greater emphasis needs to be placed on the development and integration of communication strategies into critical care nursing practice

Ownership Change, Productivity, and Human Capital: New Evidence from Matched Employer-Employee Data in Swedish Manufacturing

Empirical studies of the impact of changes in ownership of manufacturing plants on productivity (e.g., Lichtenberg and Siegel (1987, 1990a, 1990b), McGuckin and Nguyen (1995, 2001), and Maksimovic and Phillips (2001)) have provided limited evidence on how such transactions affect investment in human capital and have been based strictly on U.S. and U.K. data. We attempt to fill these gaps, based on an analysis of matched employer-employee data from over 19,000 Swedish manufacturing plants for the years 1985-1998. The sample covers virtually the entire population of manufacturing plants with 20 or more employees and a probability-based sample of smaller plants. We assess whether there are differential effects on productivity and human capital for different types of ownership changes, such as partial and full acquisitions and divestitures, and related and unrelated acquisitions. Our results suggest that ownership change results in an increase in relative productivity. We also find that plants involved in these transactions experience increases in average employee age, experience, and the percentage of employees with a college education. Ownership change also leads to an increase in wages and a reduction in the percentage of female workers. All of these patterns emerge most strongly for full acquisitions and divestitures and unrelated acquisitions.

Electrolysis of simulated lunar melts

Electrolysis of molten lunar soil or rock is examined as an attractive means of wresting useful raw materials from lunar rocks. It requires only hat to melt the soil or rock and electricity to electrolyze it, and both can be developed from solar power. The conductivities of the simple silicate diopside, Mg CaSi2O6 were measured. Iron oxide was added to determine the effect on conductivity. The iron brought about substantial electronic conduction. The conductivities of simulated lunar lavas were measured. The simulated basalt had an AC conductivity nearly a fctor of two higher than that of diopside, reflecting the basalt's slightly higher total concentration of the 2+ ions Ca, Mg, and Fe that are the dominant charge carriers. Electrolysis was shown to be about 30% efficient for the basalt composition

Pre-service teachers engaged in noticing aspects of learner written work

The study reported on here focused on pre-service teachers noticing learner thinking in the context of written work. The results show how pre-service teachers engaged in noticing learner thinking and on which aspects of learner thinking they focused. These results and related discussion broaden our conceptualisation of teacher noticing learner thinking as involving both disciplinary and non-disciplinary-specific aspects and provides related pedagogical implications for those who educate teachers. Keywords: learner thinking; mathematics education; teacher education; teacher noticin

The Moduli Space of Noncommutative Vortices

The abelian Higgs model on the noncommutative plane admits both BPS vortices and non-BPS fluxons. After reviewing the properties of these solitons, we discuss several new aspects of the former. We solve the Bogomoln'yi equations perturbatively, to all orders in the inverse noncommutivity parameter, and show that the metric on the moduli space of k vortices reduces to the computation of the trace of a k-dimensional matrix. In the limit of large noncommutivity, we present an explicit expression for this metric.Comment: Invited contribution to special issue of J.Math.Phys. on "Integrability, Topological Solitons and Beyond"; 10 Pages, 1 Figure. v2: revision of history in introductio