438 research outputs found

    Generalizing Refinement Operators to Learn Prenex Conjunctive Normal Forms

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    Inductive Logic Programming considers almost exclusively universally quantied theories. To add expressiveness, prenex conjunctive normal forms (PCNF) with existential variables should also be considered. ILP mostly uses learning with refinement operators. To extend refinement operators to PCNF, we should first do so with substitutions. However, applying a classic substitution to a PCNF with existential variables, one often obtains a generalization rather than a specialization. In this article we define substitutions that specialize a given PCNF and a weakly complete downward refinement operator. Moreover, we analyze the complexities of this operator in different types of languages and search spaces. In this way we lay a foundation for learning systems on PCNF. Based on this operator, we have implemented a simple learning system PCL on some type of PCNF.learning;PCNF;completeness;refinement;substitutions

    The Extended Transportation-Imagery Model: A Meta-Analysis of the Antecedents and Consequences of Consumers’ Narrative Transportation

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    Stories, and their ability to transport their audience, constitute a central part of human life and consumption experience. Integrating previous literature derived from fields as diverse as anthropology, marketing, psychology, communication, consumer, and literary studies, this article offers a review of two decades’ worth of research on narrative transportation, the phenomenon in which consumers mentally enter a world that a story evokes. Despite the relevance of narrative transportation for storytelling and narrative persuasion, extant contributions seem to lack systematization. The authors conceive the extended transportation-imagery model (ETIM), which provides not only a comprehensive model that includes the antecedents and consequences of narrative transportation but also a multidisciplinary framework in which cognitive psychology and consumer culture theory cross-fertilize this field of inquiry. The authors test the model using a quantitative meta-analysis of 132 effect sizes of narrative transportation from 76 published and unpublished articles and identify fruitful directions for further research

    Generalizing Refinement Operators to Learn Prenex Conjunctive Normal Forms

    Get PDF
    Inductive Logic Programming considers almost exclusively universally quantied theories. To add expressiveness, prenex conjunctive normal forms (PCNF) with existential variables should also be considered. ILP mostly uses learning with refinement operators. To extend refinement operators to PCNF, we should first do so with substitutions. However, applying a classic substitution to a PCNF with existential variables, one often obtains a generalization rather than a specialization. In this article we define substitutions that specialize a given PCNF and a weakly complete downward refinement operator. Moreover, we analyze the complexities of this operator in different types of languages and search spaces. In this way we lay a foundation for learning systems on PCNF. Based on this operator, we have implemented a simple learning system PCL on some type of PCNF

    Novel deletions causing pseudoxanthoma elasticum underscore the genomic instability of the ABCC6 region

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    Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a heritable disease that affects elastic fibers. Thus far, >200 mutations have been characterized by various PCR-based techniques (primarily direct sequencing), identifying up to 90% of PXE-causing alleles. This study wanted to assess the importance of deletions and insertions in the ABCC6 genomic region, which is known to have a high recombinational potential. To detect ABCC6 deletions/insertions, which can be missed by direct sequencing, multiplex ligation-dependent probe amplification (MLPA) was applied in PXE patients with an incomplete genotype. MLPA was performed in 35 PXE patients with at least one unidentified mutant allele after exonic sequencing and exclusion of the recurrent exon 23-29 deletion. Six multi-exon deletions and four single-exon deletions were detected. Using MLPA in addition to sequencing, we expanded the ABCC6 mutation spectrum with 9 novel deletions and characterized 25% of unidentified disease alleles. Our results further illustrate the instability of the ABCC6 genomic region and stress the importance of screening for deletions in the molecular diagnosis of PXE. Journal of Human Genetics (2010) 55, 112-117; doi: 10.1038/jhg.2009.132; published online 15 January 201
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