Invariant assertions play an important role in the analysis and documentation of while loops of imperative programs. Invariant functions and invariant relations are alternative analysis tools that are distinct from invariant assertions but are related to them. In this paper we discuss these three concepts and analyze their relationships. The study of invariant functions and invariant relations ...

While cannabis is the most frequently found illegal drug in drivers killed or injured in motor vehicle collisions, little is know about driving under the influence of cannabis (DUIC) in the general population. We report information on the incidence of DUIC in a representative sample of the Ontario adult population. Among all drivers, 1.9% reported DUIC in the previous 12 months. Several factors...

AIM An unprecedented decline in alcohol consumption and road mortality has been observed recently in France, but it is still unclear whether or not these changes affected driving while alcohol-intoxicated (DWI). The objective of the study was to estimate prospectively trends of excessive speed on the roads, alcohol consumption and DWI between 2001 and 2007 in a large cohort of experienced drive...

The extent and nature of the use of medicinal drugs by drivers who had undergone a blood test on suspicion of driving under the influence of alcohol was ascertained by analysing some 40,000 case records in which the suspect had been questioned about the use of drugs. No chemical analyses were performed. 9.7% of the road users indicated that they used drugs in combination with alcohol, and more ...

This paper gives an analysis of the connective while and the way it functions in context, based on a study of a set of while-clauses in two di erent text types. I propose to view while as one connective with a basic meaning and a number of di erent surface realizations. I show that di erent interpretations of while are subject to constraints coming from di erent directions, and that in determin...

AIM In February 2000, a trial started with Saturday opening of alcohol retail shops in certain parts of Sweden (phase I), and in July 2001, Saturday opening was extended to the whole country (phase II). The aim of this study is to assess the impact of phase II, and to probe previous results regarding phase I. DESIGN Prior to February 2000, all alcohol monopoly outlets were closed on Saturdays...

BACKGROUND Alcohol-impaired driving is a major public health problem. National studies indicate that about 25% of college students have driven while intoxicated in the past month and an even greater percentage drive after drinking any alcohol and/or ride with an intoxicated driver. The purpose of this investigation was to examine the change in these various alcohol-related traffic risk behavior...