965 resultados para Boolean Functions, Nonlinearity, Evolutionary Computation, Equivalence Classes
Resumo:
L'àmbit d'aquest treball és la generació automàtica de les restriccions d'integritat (claus primàries, alternatives i comprovacions), tant per a les bases de dades relacionals com per a les orientades a objectes.
Resumo:
This article studies the diffusion of the main institutional feature of regulatory capitalism, namely, independent regulatory agencies. While only a few such authorities existed in Europe in the early 1980s, by the end of the twentieth century they had spread impressively across countries and sectors. The analysis finds that three classes of factors (bottom-up, top-down, and horizontal) explain this trend. First, the establishment of independent regulatory agencies was an attempt to improve credible commitment capacity when liberalizing and privatizing utilities and to alleviate the political uncertainty problem, namely, the risk to a government that its policies will be changed when it loses power. Second, Europeanization favored the creation of independent regulators. Third, individual decisions were interdependent, as governments were influenced by the decisions of others in an emulation process where the symbolic properties of independent regulators mattered more than the functions they performed.
Resumo:
C(4) photosynthesis is an adaptation over the classical C(3) pathway that has evolved multiple times independently. These convergences are accompanied by strong variations among the independent C(4) lineages. The decarboxylating enzyme used to release CO(2) around Rubisco particularly differs between C(4) species, a criterion used to distinguish three distinct biochemical C(4) subtypes. The phosphoenolpyruvate carboxykinase (PCK) serves as a primary decarboxylase in a minority of C(4) species. This enzyme is also present in C(3) plants, where it is responsible for nonphotosynthetic functions. The genetic changes responsible for the evolution of C(4)-specific PCK are still unidentified. Using phylogenetic analyses on PCK sequences isolated from C(3) and C(4) grasses, this study aimed at resolving the evolutionary history of C(4)-specific PCK enzymes. Four independent evolutions of C(4)-PCK were shown to be driven by positive selection, and nine C(4)-adaptive sites underwent parallel genetic changes in different C(4) lineages. C(4)-adaptive residues were also observed in C(4) species from the nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME) subtype and particularly in all taxa where a PCK shuttle was previously suggested to complement the NADP-ME pathway. Acquisitions of C(4)-specific PCKs were mapped on a species tree, which revealed that the PCK subtype probably appeared at the base of the Chloridoideae subfamily and was then recurrently lost and secondarily reacquired at least three times. Linking the genotype to subtype phenotype shed new lights on the evolutionary transitions between the different C(4) subtypes.
Transnational study of roles/functions and associated ICT competencies for Higher Education teachers
Resumo:
Aquest estudi forma part del projecte eLene-TLC1 Virtual Campus (2007-2008) recolzat pel programa eLearning de la Comissió Europea. L'objectiu d'aquest projecte és que els professors i els estudiants facin el millor ús possible de les TIC en l'educació superior, preparant als professors per als estudiants de la generació xarxa, permetent als estudiants a la transferència de coneixements i pràctiques de la vida quotidiana per al seu aprenentatge i estimular tant la integració plena de pràctiques innovadores d'ensenyament i d'aprenentatge possibilitades per un entorn tecnològic en constant evolució. Per tal de cobrir part d'aquest objectiu general, es va concebre un estudi per examinar les competències en TIC professors d'Educació Superior en entorns d'aprenentatge en línia.