D-optimal design for a quadratic log contrast model for experiments with mixtures

A practical method is suggested for solving complicated D-optimal design problems analytically. Using this method the author has solved the problem for a quadratic log contrast model for experiments with mixtures introduced by J. Aitchison and J. Bacon-Shone. It is found that for a symmetric subspace of the finite dimensional simplex, the vertices and the centroid of this subspace are the only possible support points for a D-optimal design. The weights that must be assigned to these support points contain irrational numbers and are constrained by a system of three simultaneous linear equations, except for the special cases of 1- and 2-dimensional simplexes where the situation is much simpler. Numerical values for the solution are given up to the 19-dimensional simplex     

A New Model of Trend Inflation

This article introduces a new model of trend inflation. In contrast to many earlier approaches, which allow for trend inflation to evolve according to a random walk, ours is a bounded model which ensures that trend inflation is constrained to lie in an interval. The bounds of this interval can either be fixed or estimated from the data. Our model also allows for a time-varying degree of persistence in the transitory component of inflation. In an empirical exercise with CPI inflation, we find the model to work well, yielding more sensible measures of trend inflation and forecasting better than popular alternatives such as the unobserved components stochastic volatility model. This article has supplementary materials online.     

Time Series Modeling of Degradation Due to Outdoor Weathering

Environmental variables have an important effect on the reliability of many products such as coatings and polymeric composites. Long-term prediction of the performance or service life of such products must take into account the probabilistic/stochastic nature of the outdoor weather. In this article, we propose a time series modeling procedure to model the time series data of daily accumulated degradation. Daily accumulated degradation is the total amount of degradation accrued within one day and can be obtained by using a degradation rate model for the product and the weather data. The fitted model of the time series can then be used to estimate the future distribution of cumulative degradation over a period of time, and to compute reliability measures such as the probability of failure. The modeling technique and estimation method are illustrated using the degradation of a solar reflector material. We also provide a method to construct approximate confidence intervals for the probability of failure.     

Occupational rehabilitation services provided by a community workers health centre in Hong Kong: a case study

Ergonomics is commonly known as "the scientific study of human work" [14, p. 3] and "the application of scientific information concerning human beings to the design of objects, systems, and environments" (p. 4). The American Occupational Therapy Association defines occupational therapy as "skilled treatment that helps individuals achieve independence in all facets of their lives. It gives people the 'skills for the job of living' necessary for independent and satisfying lives [1]." Both professions share common backgrounds. Occupational therapy has been involved in health care and ergonomics is looking for its place in the health care field.     

Living arrangements of older malaysians: Who coresides with their adult children?

More than two-thirds of Malaysians age 60 or older coreside with an adult child. Data from the Senior sample of the Second Malaysian Family Life Survey (MFLS-2) are used to investigate which “seniors” (persons age 60 or older) live in this way. The analysis generally supports the notion that coresidence is influenced by the benefits, costs, opportunities, and preferences for coresidence versus separate living arrangements. For example, married seniors are more likely to coreside with adult children when housing costs are greater in their area or when the husband or wife is in poor health. This finding suggests that married parents and children live together to economize on living costs or to receive help with household services. Unmarried seniors who are better off economically are less likely to live with adult children, presumably because they use their higher incomes to “purchase privacy.”     

Comorbid mood and adjustment disorders among pathological gamblers seeking treatment in Hong Kong

Research findings on comorbidity and pathological gambling are non–existent in Chinese communities. The objectives of this study were to: (a) determine the prevalence of comorbid mood and adjustment disorders among pathological gamblers seeking treatment in Hong Kong; (b) compare demographic profiles and clinical features in pathological gamblers with and without comorbid mood and adjustment disorders; and (c) explore the association and temporal relationship between pathological gambling and comorbid mood and adjustment disorders. Assessment instruments included demographic data, BSI, SCID-I, ASI and LIFE-RIFT. Results showed that about two-thirds (63.7%; n = 128) of 201 participants reported lifetime comorbid psychiatric disorders. Most common comorbid disorders were mood disorders (29.4%; n = 59) and adjustment disorders (20.9%; n = 42). Pathological gamblers with comorbid mood or adjustment disorders showed more severe levels of psychopathology, impairment in psychosocial functioning and gambling problems. This study is important because it is the first scientific comorbidity study among pathological gamblers in a Chinese context.     

The Role of Behavioral Responses in the Total Economic Consequences of Terrorist Attacks on U.S. Air Travel Targets

U.S. airports and airliners are prime terrorist targets. Not only do the facilities and equipment represent high‐value assets, but the fear and dread that is spread by such attacks can have tremendous effects on the U.S. economy. This article presents the methodology, data, and estimates of the macroeconomic impacts stemming from behavioral responses to a simulated terrorist attack on a U.S. airport and on a domestic airliner. The analysis is based on risk‐perception surveys of these two scenarios. The responses relate to reduced demand for airline travel, shifts to other modes, spending on nontravel items, and savings of potential travel expenditures by U.S. resident passengers considering flying domestic routes. We translate these responses to individual spending categories and feed these direct impact results into a computable general equilibrium (CGE) model of the U.S. economy to ascertain the indirect and total impacts on both the airline industry and the economy as a whole. Overall, the estimated impacts on GDP of both types of attacks exceed $10B. We find that the behavioral economic impacts are almost an order of magnitude higher than the ordinary business interruption impacts for the airliner attack and nearly two orders of magnitude higher for the airport attack. The results are robust to sensitivity tests on the travel behavior of U.S. residents in response to terrorism.     

Developing From Tranditional Microscale Chemistry to Microscale Green Chemistry

Microscale chemistry is appealing to all levels of education.In contrast to conventional macroscale chemistry,only minute amount of chemicals are required to undertaking a chemical investigation.     

赫胥黎在近代科学教育普及和发展中的作用

赫胥黎的科学教育思想引领了英国皇家矿业学院的发展,推动了实验室教学的普及,奠定了科学在学校教育体系中的合法地位,促进了科学教育重心的转移,在一定程度上协调了科学教育和自由教育的关系,深刻影响了19世纪中期以后英国乃至欧美其他国家教育的改革和发展,对于我们当今的科学教育工作仍具有十分重要的启示和借鉴意义。