The RISA Architecture is a novel reconfigurable hardware platform containing both hardware and software reconfigurable elements. This paper describes the architecture and the features that make it suitable for implementing biologically inspired systems such as the evolution of digital circuits. Some of the architecture’s capabilities are demonstrated with the results of evolving a simple combin...

Risa/Asir consists of the Risa engine for performing operations on mathematical objects and an interpreter for programs written in the Asir user language. In Risa/Asir, polynomials are represented in two different internal forms: the recursive representation and the distributed representation. Polynomial factorization and GCD are based on the former representation, and computations related to t...

The concentration of protein in the cerebrospinal fluid (CSF) is about 0.5 per cent that of plasma. This difference in concentration is generally considered (1) to be dependent upon the blood-CSF barrier. The normal concentration gradient of protein from a low level in the ventricles, 6 to 15 mg. per cent, to an intermediate level in the cisterna magna, 15 to 25 mg. per cent, to the highest lev...

Este texto evalúa las semejanzas y, sobre todo, diferencias entre «risa» animal y risa humana, reflexionando, a partir de la ciencia filosofía contemporáneas, una vieja tésis aristotélica: que el hombre es ríe.

We elaborate on the semantics of an enhanced object-oriented semantic network, where multiple instantiation, multiple specialization, and meta-classes are supported for both kinds of objects: entities and properties. By semantics of a semantic network, we mean the information (both explicit and derived) that the semantic network carries. Several data models use semantic networks to organize inf...

We elaborate on the semantics of an enhanced object oriented semantic network where multiple instantiation multiple specialization and meta classes are supported for both kinds of objects entities and properties By semantics of a semantic network we mean the information both explicit and derived that the semantic network carries Several data models use semantic networks to organize information ...

The impact of three different soil DNA extraction methods on bacterial diversity was evaluated using PCR-based 16S ribosomal DNA analysis. DNA extracted directly from three soils showing contrasting physicochemical properties was subjected to amplified ribosomal DNA restriction analysis and ribosomal intergenic spacer analysis (RISA). The obtained RISA patterns revealed clearly that both the ph...

Two major emerging bands (a 350-bp band and a 650-bp band) within the RISA (ribosomal intergenic spacer analysis) profile of a soil bacterial community spiked with Hg(II) were selected for further identification of the populations involved in the response of the community to the added metal. The bands were cut out from polyacrylamide gels, cloned, characterized by restriction analysis, and sequ...

Most studies concerning effects of neural stimuli on the cerebral circulation have focused on changes in cerebral blood flow (CBF). The purpose of this study was to examine effects of sympathetic nerves on permeability of the blood-brain barrier (BBB) to albumin, using a quantitative method, and to relate changes in blood flow to changes in permeability of the BBB. Permeability of the BBB was e...

Patterns of change in the structure of bacterial communities monitored by ribosomal intergenic spacer analysis (RISA) in oil contaminated sediments inhabited or not by the marine polychaete Nereis diversicolor were studied during 45 days under laboratory conditions. Results supported by principal component analysis showed a marked response of the bacterial communities to the oil contamination a...