We give a presentation of Pure type systems where contexts need not be well-formed and show that this is equivalent to the usual one. The main motivation for that, when we extend with computation rules, like in logical framework Dedukti, want declare constants before rules are needed check well-typedness their type.

OBJECTIVE This article examines noncausal associations between high school seniors' alcohol and marijuana use status and rates of self-reported unsafe driving in the past 12 months. METHOD Analyses used data from 72,053 students collected through annual surveys of nationally representative cross-sectional samples of U.S. 12th-grade students from 1976 to 2011. Two aspects of past-12-month alco...

Volume 28, Number 4, December 2002 In Latin America and the Caribbean, more than 95% of induced abortions are performed illegally, often in unsafe conditions.*1 Unsafe abortions occur at a higher rate in this region than in any other region in the world: Each year, 30 of every 1,000 women of reproductive age in Latin America and the Caribbean have an unsafe abortion, compared with 27 per 1,000 ...

OBJECTIVE Since 1999, substantial efforts have been made by the international community to reduce the risks associated with unsafe injections, through ministries of health, international donors, the World Health Organization and the Safe Injection Global Network. The present study attempted to measure the progress, or lack thereof, made over the 2000-2010 decade in reducing unsafe injections in...

The precondition for safe execution of a procedure is useful for understanding, verifying and debugging programs. We have previously presented a cegar-based approach for inferring necessary and sufficient preconditions based on the iterative abstraction-refinement of the set of safe and unsafe states until they become disjoint. A drawback of that approach is that safe and unsafe traces are expl...