Blinded continuous monitoring in clinical trials with recurrent event endpoints

In studies with recurrent event endpoints, misspecified assumptions of event rates or dispersion can lead to underpowered trials or overexposure of patients. Specification of overdispersion is often a particular problem as it is usually not reported in clinical trial publications. Changing event rates over the years have been described for some diseases, adding to the uncertainty in planning. To mitigate the risks of inadequate sample sizes, internal pilot study designs have been proposed with a preference for blinded sample size reestimation procedures, as they generally do not affect the type I error rate and maintain trial integrity. Blinded sample size reestimation procedures are available for trials with recurrent events as endpoints. However, the variance in the reestimated sample size can be considerable in particular with early sample size reviews. Motivated by a randomized controlled trial in paediatric multiple sclerosis, a rare neurological condition in children, we apply the concept of blinded continuous monitoring of information, which is known to reduce the variance in the resulting sample size. Assuming negative binomial distributions for the counts of recurrent relapses, we derive information criteria and propose blinded continuous monitoring procedures. The operating characteristics of these are assessed in Monte Carlo trial simulations demonstrating favourable properties with regard to type I error rate, power, and stopping time, ie, sample size.     

Behavioral responses of rural and urban greater white-toothed shrews (Crocidura russula) to sound disturbance

Urban Ecosystems - The development of urban areas imposes challenges that wildlife must adapt to in order to persist in these new habitats. One of the greatest changes brought by urbanization has...     

What is educational entrepreneurship? Strategic action,temporality, and the expansion of US higher education

Theory and Society - The massive expansion of US higher education after World War II is a sociological puzzle: a spectacular feat of state capacity-building in a highly federated polity. Prior...     

Philippine NGOs and Multistakeholder Partnerships: Three Case Studies

This paper discusses an emerging role for Philippine NGOs—building and maintaining intersectoral cooperation among various sectors of society to tackle key issues like agricultural development, HIV/AIDS, and agrarian reform. The three case studies elaborated in the paper show that Philippine NGOs play important intermediary and bridging functions crucial for the success of multistakeholder partnerships. NGOs are well equipped for this because of their middle-class and professional nature and because of various characteristics like autonomy, flexibility, and the ability to mobilize resources.     

A class of symmetric bivariate uniform distributions

A class of symmetric bivariate uniform distributions is proposed for use in statistical modeling. The distributions may be constructed to be absolutely continuous with correlations as close to±1 as desired. Expressions for the correlations, regressions and copulas are found. An extension to three dimensions is proposed.     

Career Self‐Efficacy and Perceptions of Parent Support in Adolescent Career Development

The authors examined the relative contributions of both proximal and distal supports to the career interests and vocational self‐efficacy in a multiethnic sample (N = 139) of middle school adolescents. Consistent with Social Cognitive Career Theory, it was found that (a) vocational self‐efficacy and career planning/exploration efficacy consistently predicted young adolescents' career interests across Holland (J. L. Holland, D. R. Whitney, N. S. Cole, & J. M. Richards, 1969) themes; (b) gender and career gender‐typing predicted interests in Realistic, Investigative, and Social careers; and (c) perceived parent support accounted for 29% to 43% of the total unique variance in vocational self‐efficacy for all Holland theme careers.     

Expectations, Capital Gains, and Income

A theoretical framework for the measurement of income under uncertainty is developed that addresses some long-standing controversies about the treatment of capital gains. The consequences for economic analysis and policy making are potentially serious, because the treatment of capital gains can significantly affect some major macroeconomic aggregates, including national income and savings, balance of payments deficits, government deficits, and depreciation. (JEL O47 , P44 , Q32 )     

Campus attitudes toward alcohol and drugs in a deep southern university.

In our zeal to deal with alcohol and drug abuse, we may have a distorted picture of what the majority of college students actually think about alcohol and drug use. Students in this study done at a public university located in the Deep South report being generally intolerant of substance abuse.