Expressiveness of Temporal Query Languages: On the Modelling of Intervals, Interval Relationships and States

Storing and retrieving time-related information are important, or even critical, tasks on many areas of Computer Science (CS) and in particular for Artificial Intelligence (AI). The expressive power of temporal databases/query languages has been studied from different perspectives, but the kind of temporal information they are able to store and retrieve is not always conveniently addressed. Here we assess a number of temporal query languages with respect to the modelling of time intervals, interval relationships and states, which can be thought of as the building blocks to represent and reason about a large and important class of historic information. To survey the facilities and issues which are particular to certain temporal query languages not only gives an idea about how useful they can be in particular contexts, but also gives an interesting insight in how these issues are, in many cases, ultimately inherent to the database paradigm. While in the area of AI declarative languages are usually the preferred choice, other areas of CS heavily rely on the extended relational paradigm. This paper, then, will be concerned with the representation of historic information in two well known temporal query languages: it Templog in the context of temporal deductive databases, and it TSQL2 in the context of temporal relational databases. We hope the results highlighted here will increase cross-fertilisation between different communities. This article can be related to recent publications drawing the attention towards the different approaches followed by the Databases and AI communities when using time-related concepts

Measurement of the 2s 2p2^{2}(4^{4}P) 3s 3^{3}P2_{2} lifetime in N II by beam-foil-laser spectroscopy

An accurate value for the radiative lifetime of the 2s 2p$^{2}$($^4$P) 3s $^3$P$_{2}$ level in N II has been obtained using the beam-foil-laser spectroscopy method. The results $(\tau = 0.456\pm 0.020$ ns) is shorter than the beam-foil lifetime values reported previously for the 3s$'$ $^3$P term. No theoretical value for the lifetime of this term is available at the present time.Nous avons mesuré avec précision la durée de vie radiative du niveau 2s 2p$^{2}$($^4$P) 3s $^3$P$_{2}$ de N II par la méthode de spectroscopie faisceau-lame-laser. La durée de vie obtenue $(\tau = 0.456\pm 0.020$ ns) est plus courte que celles mesurées précédemment, par spectroscopie faisceau-lame, pour le terme 3s$'$ $^3$P de N II. Aucune valeur théorique de la durée de vie de ce terme n'est actuellement disponible

Psycho-Oncol

Videoconference-based group interventions aim to facilitate access to the supportive care. Very little data are available on the interactional specificities that this recent device could imply. This article describes the exploratory research process used to build an observation grid in order to study this relational question from collective thematic workshops in cancer patients