Body support testing and rating

The REF, C, and score are a means to give quantitative values for product performance. Other product variables defined as humidity control factor, shear control factor, differential temperature control factor, product life factor, and cost factor were not addressed as part of this study. Additional variables include delivery, maintenance, and warranties. These components can be added to the score in some weighted manner as they become clinically founded. Interface pressures and shears were not measured for beds that are gatched. Each product tested will have characteristics pertinent to its own design that must be addressed to minimize sacral and coccyx skin breakdown when subjects are in this posture because some pneumatic pads bottom out to give excessive sacral and coccyx pressure while others wrinkle when used in this position. This is of major concern when one considers that the coccyx is more susceptible to pressure than any other bony prominence. There may be some aversion to labeling support product performance because it will allow the purchaser to know what is being bought. This initial study indicates the feasibility of quantitating what all patients require: a valid interface support surface for each specific need. The user can be adequately informed before the purchase as to a product's merits without being influenced by the results of inadequate testing, referrals, or sales media influences. Although cushions, shoes, or other prosthetic/orthotic devices were not part of this study, it is appropriate to rate all these devices in a similar manner by simply comparing pressure relief attained to that desired, expressing the result as a percentage of the worst case, and then labeling the product accordingly. Those subjects with sensation can rate comfort as part of the overall score. For cushions, ischial tuberosity pressure relief can be expressed as a percentage of the maximum attainable relief. Metatarsal head relief during gait as well as during static testing can be measured, and claims can be made for shoes and sneakers. Where impact loads and shear forces are paramount, the score must comprise appropriate parameters. Similarly, amputee distal stump relief as a percentage of worst case could be specified by the fitter. Iliac crest relief as a percentage of worst case can also be specified by the fitter. In all instances the score is not a subjective rating but one that can be measured correctly. All body support products can be given an REF, C value, and score as well as other qualifying values where appropriate instrumentation and sufficient subject sampling is used.     

Yes, the market can curb health costs

Memo to Clinton's transition team: forget those tough expenditure ceilings you're considering. Look instead at what managed competition is already accomplishing.     

Preliminary test estimators of the parameters of simple linear model with measurement error

In this paper, we discuss the properties of preliminary test estimators (PTE) of the parameters of simple linear model with measurement error (ME model) when the slope of the linear model is suspected to be zero. Expressions of the bias, MSE and efficiencies are obtained under conditional as well as unconditional situations with known reliability coefficient. Conditional model results are compared to the standard model without measurement error. We also provide the unconditional model analysis in finite samples. Asymptotic theory under local alternatives is developed when the variance of measurement error or the ratio of the variance of the model error relative to the variance of the measurement error is known. Asymptotic expressions of bias and MSE of the estimators along with their efficiencies are obtained. In every case, it is shown that the measurement error tend to increase the variability of the estimators compared to the estimators without measurement error. Graphs and tables are provided to see these results and to determine optimum level of significance for minimum guaranteed efficiency. Received October 2001 RID="*" ID="*"  A. K. Md. E. Saleh is a Distinguished Research Professor and H. M. Kim is a Ph.D. candidate in the School of Mathematics and Statistics, Carleton University, Ottawa. Acknowledgment. The authors gratefully acknowledge the constructive suggestion of the referees to improve the paper. The research is supported by NSERC grant A3088.     

Local and National Impacts from Landing North Sea Gas in Western Norway

A bstract . A simple framework is presented for the analysis of the local employment, income, sales , and local government impacts of landing North Sea gas at either of two Norwegian kommunes (municipalities). These impacts indicate the different forms of economic change arising from a major economic development event. The average annual net change in these economic measures is estimated for the operational phase of a gas terminal. The analysis indicated substantial differences in local and regional net gains. Both sites yielded positive neteconomic gains, which means noneconomic and national considerations become key decision determinates. These national issues provide the setting to judge the local/regional net gains. The unresolved questions include the national benefits and costs of the landing decision given the small scale of the Norwegian economy, potential future gas finds, and a fully employed economy.     

An effective step-down algorithm for the construction and the identification of nonisomorphic orthogonal arrays

In this paper we present an effective algorithm for the construction and the identification of two-level nonisomorphic orthogonal arrays. Using this algorithm, we identify and list a full catalogue of nonisomorphic orthogonal arrays with parameters OA(24,7,2,t), OA(28,6,2,t) and OA(32,6,2,t), t ≥ 2. Some statistical properties of these designs are also considered.     

The long-run relationship between private and public savings: An empirical note

This empirical note extends the recent work by Holmes (2006) in examining the long-run relationship between private and public savings in the U.S. over the post-World War II period. Standard Engle-Granger cointegration tests fail to reject the null hypothesis of no cointegration; however, once allowance is made for an endogenous break in the cointegrating relationship, the weak form of the Ricardian equivalence proposition is supported.     

Flexibility at different stages in the life cycle of projects: An empirical illustration of the “freedom to maneuver”

Many textbooks on project management present illustrations concerning the relative size of project attributes during different project phases. The derived models all have attributes in common, such as uncertainty, significance of decisions, and degree of freedom to maneuver, that are typically high in the beginning of the project and low in the end. At the same time, variables such as the accumulated cost and available information begin at low levels and end up at a high level at the end of the project. Based on empirical data from projects, this paper illustrates and quantifies one of these attributes, the freedom to maneuver, in different project phases.     

Property taxes and the timing of urban land development

This paper develops an optimal timing model which extends our understanding of the effects which property taxes have on the timing of land development. Comparative static effects of changes in property tax rates are investigated and policy rules are developed for the use of differential pre- and post-development tax rates to affect the timing of development. Changes in the property tax rate are found to be non-neutral with respect to the timing of development in most cases, accelerating or delaying development depending upon specific market conditions.