Due to weather-related travel delays Dr. McCarthy was unable to present his scheduled paper. In his absence, however, Dr. K. Yokoyama, Chairman of the International Earth Rotation Service (IERS), reported on the status of the revision of the IERS Standards carried out by McCarthy who provided the following precis.These standards are meant to be used in the reduction of observations contributed to the IERS and by those who require IERS estimates of polar motion, Universal Time and nutation to establish the most precise celestial and terrestrial reference systems. The goal of the IERS is to publish the document, an update of the previous version (McCarthy, 1989), in the beginning of 1992.

S U M M A R YHistorical sources of polar motion are analysed together with modern data in order to compile a set of coordinates of the mean pole in a reference system consistent with that of the International Earth Rotation Service. The trend and quasi-periodic motion of the pole are investigated, and we find that the rotational pole appears to be moving at the rate of 0.333 arcsec century-' in the direction of 75.0" west longitude. Modern data also appear to be consistent with the possible existence of very low-frequency periodic motion (Markowitz wobble).

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The HiPAC project is investigating active, time-constrained database managment. An active DBMS is one which automatically executes specified actions when speciifed conditions arise. HiPAC has proposed Event-Condition-Action (ECA) rules as a formalism for active database capabilities. We have also developed an execution model that speicifes how these rules are processed in the context of database transactions. The additional functionality provided by ECA rules makes new demands on the design of an active DBMS. In this paper we propose an architecture for an active DBMS that supports ECA rules. This architecture provides new forms of interaction, in support of ECA rules, between application programs and thDBMS.This leads to a new paradigm for constructing database applications.