An Epidemiologic Note on Verification Bias: Implications for Estimation of Rates

Two-stage designs offer several advantages for purposes of test validation and prevalence estimation. These include enhanced precision and increased cost-efficiency. Cost efficiency is obtained when the best available verification criterion is too expensive to employ in a large-scale epidemiologic study. The use of two-stage (or double-sampling) designs permit the same inferences from application to only a subset of those who were screened (with the less expensive criterion) during stage one. The retesting of only some of the first stage respondents introduces a bias, however, if these are sampled on the basis of first stage screening results. The form of this bias is described and solutions for correcting estimates are provided. These solutions are applied to the data reported by Abbott and Volberg (1996) in their study of the New Zealand general population. Corrected estimates of the sensitivity and specificity of the South Oaks Gambling Screen are obtained and used to adjust the reported lifetime and current prevalence estimates. The value of multi-stage designs for validity assessment and prevalence estimation are briefly described.     

Treatment of noncustodial fathers: Gender issues and clinical dilemmas

This article addresses issues involved in the treatment of fathers who do not have custody of their children. It reviews literature on demographic trends and discusses fathers' reactions to loss of child custody. Assessment and treatment guidelines are offered so that clinical practice may become more responsive to the needs of the population. Gender concerns, particularly as they relate to transference and countertransference, are also discussed.     

Utilization of Family Photos and Movies in Family Therapy

This article discusses a technique the authors have designated Family Photo Reconnaisance. They describe the rationale for and process of utilizatizing family photographs and movies in family therapy sessions to evoke past events and memories and to uncover feelings about these occurrences and the people involved in them. Through their utilization, how one has changed over time is vividly seen. Who is missing from the constellation and when they "dropped out of the family orbit becomes obvious as do distorted memories. Family members reexperiencing the past together around their photographs come to better appreciate one another's current feelings and behavior and often are enabled to gain mastery over unresolved conflicts.     

The effects of a continuous passive motion device on myoelectric activity of the erector spinae during prolonged sitting at a computer workstation

Continuous passive motion (CPM) has been proposed as a method to help individuals with low back pain cope with prolonged sitting. The purpose of this study was to investigate the effects that a commercially available CPM device had on lumbar and thoracic erector spinae (ES) muscle activation (using surface electromyography, "EMG"), and on subjective discomfort during prolonged seated computer work with and without the use of the CPM device. There were no significant differences in average ES muscle activation levels, amplitude probability distribution functions, and EMG gaps number and length when sitting with the CPM device was compared to sitting normally. Subjective ratings of discomfort were also not significantly different between the two sitting conditions. The results indicated that there were no clear mechanisms by which the CPM device may reduce ES muscle pain and fatigue for the tasks and pain-free individuals studied.     

斯伦贝谢对中国的兴趣

中国的 SIM 卡和银行卡的增长2001年有望分别达到25%和50%。“中国是一个大市场,是一个很有潜力的市场,只要合理,我们就不断会在中国投资。”     

Reporting Volunteer Labour at the Organizational Level: A Study of Canadian Nonprofits

Volunteer contributions in the production of services are an important resource internationally. However, few countries include volunteer contributions in their national accounts, even though many encourage their populations to engage in volunteering. At the organizational level, many nonprofit organizations using volunteers often limit their input to a footnote in annual reports acknowledging their contribution; few estimate their value in financial terms. As a result, their financial accounts lack information upon which to base decisions affecting the organizations and the communities they serve. Additional information is required to assess the impact of volunteers in individual nonprofits as well as the sector as a whole. This study focuses on Canada, one of the few countries that include volunteers in the national accounts, to examine to what extent nonprofit organizations estimate a financial value for these contributions and include this in their financial statements. This paper reports the results of an online survey of 661 nonprofits from across Canada. In order to understand why some organizations keep records for volunteer contributions and quantify them, two sets of explanatory factors are explored: organizational characteristics and the attitude of the executive director. We find larger organizations were more likely to engage in record keeping and estimating volunteer value, as were organizations with a relatively large group of volunteers and volunteer programs. The attitude of the executive director is important in determining which organizations engage in these practices.     

The selection of zero-non-zero patterned cointegrating vectors in error-correction modelling

An effective and efficient search algorithm has been developed to select from an 1(1) system zero-non-zero patterned cointegrating and loading vectors in a subset VECM, B^q(l)y(t-1) + B^q-1 (L)Ay(t) = ε( t ) , where the long term impact matrix Bq(l) contains zero entries. The algorithm can be applied to higher order integrated systems. The Finnish money-output model presented by Johansen and Juselius (1990) and the United States balanced growth model presented by King, Plosser, Stock and Watson (1991) are used to demonstrate the usefulness of this algorithm in examining the cointegrating relationships in vector time series.