Cannabis is the world's most widely cultivated and consumed illicit drug, but there remain major gaps in our understanding of global cannabis markets. For example, it appears that premium sinsemilla cannabis, often produced indoors in consumer countries, has become more potent in recent years and that its market share is also growing in some areas. This may be leading to greater localization of...

This paper reviews the major health and pharmaceutical developments in developing countries for the past 25 years and suggest what may occur over the next 25 years. Major health, social, economic and development changes have occurred during this period. The Alma Ata declaration was pronounced in 1978 suggesting an approach to health and health services. An integral part of this approach was the...

Most existing formal models of goals [2, 3] assume that all goals are equally important and many only deal with achievement goals. Moreover, they do not guarantee that an agent’s goals will properly evolve when an action/event occurs, e.g. when the agent’s beliefs/knowledge changes or a goal is adopted or dropped. Also, most of these frameworks do not model the dependencies between goals and th...

In dynamic systems, state constraints are formulas that hold in every reachable state. It has been shown that state constraints can be used to greatly reduce the planning search space. They are also useful in program verification. In this paper, we propose a sound but incomplete method for automatic verification and discovery of ∀∗∃∗ state constraints for a class of action theories that include...

We have developed a syntactic approach to representing knowledge within the situation calculus using interval arithmetic. Knowledge was first incorporated into the situation calculus using a possible-worlds approach. Unfortunately, this previous approach is not amenable to easy implementation. This is because it is not clear how to specify the initial situation as the number of possible worlds ...

Sensing actions are important for planning with incomplete information. A solution for the frame problem for sensing actions was proposed by Scherl and Levesque. They adapt the possible world model of knowledge to situation calculus. In this paper we propose a high level language in the spirit of the language A, that allows sensing actions. We then present two approximation semantics of this la...