Abstract. The sentences of deontic logic may be understood as describing what an agent ought to do when faced with a given set of norms. If these norms come into conflict, the best the agent can be expected to do is to follow a maximal subset of the norms. Intuitively, a priority ordering of the norms can be helpful in determining the relevant sets and resolve conflicts, but a formal resolution mechanism has been difficult to provide. In particular, reasoning about prioritized conditional imperatives is overshadowed by problems such as the 'order puzzle' that are not satisfactorily resolved by existing approaches. The paper provides a new proposal as to how these problems may be overcome.

Abstract. When a conflict of duties arises, a resolution is often sought by determining an ordering of priority or importance. This paper examines how such a conflict resolution works, compares mechanisms that have been proposed in the literature, and gives preference to one developed by Brewka and Nebel. I distinguish between two cases -that some conflicts may remain unresolved, and that a priority ordering can be determined that resolves all -and provide semantics and axiomatic systems for accordingly defined dyadic deontic operators.

Deviating from standard possible-worlds semantics, authors belonging to what might be called the 'imperative tradition' of deontic logic have proposed a semantics that directly represents norms (or imperatives). The paper examines possible definitions of (monadic) deontic operators in such a semantics and some properties of the resulting logical systems.

A new method for the preparation of wood samples for high-resolution reflected-light microscopy in combination with a species-specific image analysis system is introduced. The method is based on an ultraprecise single-point diamond flycutter equipped with air bearings and functions on the basis of a rotating diamond edge. Extensive and very smooth surfaces can be produced on increment cores as well as entire cross sections. Hence, this technique provides the prerequisites for a continuous microscopic analysis across large tree-ring sequences, or entire cross sections. Patching or sub-sectioning is not required. The high-resolution analysis of cell structures of spruce and oak presented here introduces new approaches for describing and predicting reactions of diameter growth to various environmental events.

Often a set of imperatives or norms seems satisfiable from the outset, but conflicts arise when ways to fulfill all are ruled out by unfortunate circumstances. Semantic methods to handle normative conflicts were devised by B. van Fraassen and J.F. Horty, but these are not sensitive to circumstances. The present paper extends these resolution mechanisms to circumstantial inputs, defines dyadic deontic operators accordingly, and provides a sound and (weakly) complete axiomatic system for such deontic semantics.