The integration of preferences into answer set programming constitutes an important practical device for distinguishing certain preferred answer sets from non-preferred ones. To this end, we elaborate upon rule dependency graphs and their colorings for characterizing different preference handling strategies found in the literature. We start from a characterization of (three types of) preferred ...

In this paper, we study the birational geometry of the Hilbert scheme of points on a smooth, projective surface, with special emphasis on rational surfaces such as P2,P1 × P1 and F1. We discuss constructions of ample divisors and determine the ample cone for Hirzebruch surfaces and del Pezzo surfaces with K2 ≥ 2. As a corollary, we show that the Hilbert scheme of points on a Fano surface is a M...

The application of stable isotope analysis (SIA) has become a standard scientific approach in Agricultural and Ecological researches and, more in general, in several disciplines such as biology, botany, zoology, organic chemistry, climatology, and nutrition. The main objectives of this paper are (1) to provide a simple definition of stable isotopes and (2) to illustrate analytical measurement m...

passive solar systems such as solar chimneys need solar radiation in order to work. therefore, they cannot present stable natural ventilation when solar energy vanishes: to have a more robust and stable condition, solar energy should be stored during the day and released back during the night. phase change materials can save additional thermal energy during the day and release it during the nig...

This paper presents a design methodology for a class of behaviour-based control systems, arguing its potential for application to safety critical systems. We propose a formal basis for subsumption architecture design based on two extensions to Lyapunov stability theory, the Second Order Stability Theorems, and interpretations of system safety and liveness in Lyapunov stability terms. The subsum...

A new concept of stability, closely related to that of structural stability, is introduced and applied to the study of Cr endomorphisms with singularities. A map that is stable in this sense will be conjugated to each perturbation that is equivalent to it in a geometric sense. It will be shown that this kind of stability implies Axiom A, Omega-stability and that every critical point is wanderin...

Recent progress in the measurement of the bioconversion of dietary provitamin A carotenoids to vitamin A is reviewed in this article. Methods to assess the bioavailability and bioconversion of provitamin A carotenoids have advanced significantly in the past 10 y, specifically through the use of stable isotope methodology, which includes the use of labeled plant foods. The effects of the food ma...

Rats immunized with a semipurified preparation of the Escherichia coli heat-stable (ST) enterotoxin conjugated with a protein carrier were protected against challenge with semipurified or purified ST and viable organisms of multiple heterologous serotypes that produce only ST (LT-/ST+), but they were not protected against heal-labile (LT) toxin or viable strains which produce LT either alone (L...

The proposed CRP will contribute to a better understanding of the appropriate use of the stable isotope dilution technique to assess vitamin A status across the continuum from deficiency to toxicity in children under the age of 5 years. The findings will provide guidance for programme managers and public health nutrition policy makers to improve the evaluation of their vitamin A programmes, in ...