Microsatellite genotyping clarified conspicuous accumulation of Candida parapsilosis at a cardiothoracic surgery intensive care unit.

Contains fulltext : 124291.pdf (publisher's version ) (Open Access)Candida parapsilosis has become a significant cause of invasive fungal infections in seriously ill patients. Nosocomial outbreaks through direct and indirect contact have been described. The aim of this study was the molecular characterization of what appeared to be an ongoing C. parapsilosis outbreak at the cardiothoracic intensive care unit of the University Hospital of Vienna between January 2007 and December 2008. Using two different molecular typing methods-automated repetitive sequence-based PCR (DiversiLab; bioMerieux) and microsatellite genotyping-we investigated the genetic relationship of 99 C. parapsilosis isolates. Eighty-three isolates originated from the cardiothoracic intensive care unit, while 16 isolates were random control isolates from other intensive care units and a different Austrian hospital. The 99 C. parapsilosis isolates analyzed by repetitive-element PCR all showed identical genotypes, suggesting an ongoing outbreak. In contrast, microsatellite genotyping showed a total of 56 different genotypes. Two major genotypes were observed in 10 and 15 isolates, respectively, whereas another 13 genotypes were observed in 2 to 4 isolates each. Forty-one genotypes were observed only once. Closely related genotypes that differed in only a single microsatellite marker were grouped into clonal complexes. When it comes to C. parapsilosis, microsatellite genotyping is a more discriminative method than repetitive-element PCR genotyping to investigate outbreaks.1 november 201

A different perspective on canonicity

One of the most interesting aspects of Conceptual Structures Theory is the notion of canonicity. It is also one of the most neglected: Sowa seems to have abandoned it in the new version of the theory, and most of what has been written on canonicity focuses on the generalization hierarchy of conceptual graphs induced by the canonical formation rules. Although there is a common intuition that a graph is canonical if it is "meaningful'', the original theory is somewhat unclear about what that actually means, in particular how canonicity is related to logic. This paper argues that canonicity should be kept a first-class notion of Conceptual Structures Theory, provides a detailed analysis of work done so far, and proposes new definitions of the conformity relation and the canonical formation rules that allow a clear separation between canonicity and truth

Neuronal activation for semantically reversible sentences

Semantically reversible sentences are prone to misinterpretation and take longer for typically developing children and adults to comprehend; they are also particularly problematic for those with language difficulties such as aphasia or Specific Language Impairment. In our study, we used fMRI to compare the processing of semantically reversible and nonreversible sentences in 41 healthy participants to identify how semantic reversibility influences neuronal activation. By including several linguistic and nonlinguistic conditions within our paradigm, we were also able to test whether the processing of semantically reversible sentences places additional load on sentence-specific processing, such as syntactic processing and syntactic-semantic integration, or on phonological working memory. Our results identified increased activation for reversible sentences in a region on the left temporal–parietal boundary, which was also activated when the same group of participants carried out an articulation task which involved saying “one, three” repeatedly. We conclude that the processing of semantically reversible sentences places additional demands on the subarticulation component of phonological working memory

Evaluating models of working memory: FMRI and behavioral evidence on the effects of concurrent irrelevant information

FMRI and behavioral methods were used to examine working memory impairments resulting from articulatory suppression, irrelevant speech, and irrelevant nonspeech. While the deleterious effects of these three irrelevant information types are well established in the behavioral literature, theoretical models provide conflicting accounts of the origins of these effects. To adjudicate between these accounts, two experiments were conducted. Experiment 1 examined fMRI signal changes in a delayed probed recall task with articulatory suppression, irrelevant speech, or irrelevant nonspeech imposed during the encoding and delay periods. Within the principally frontal and left-lateralized network of brain regions engaged by the task, articulatory suppression caused a relative increase in activity early in the trial, while both irrelevant speech and nonspeech conditions caused relative reductions in regional activity later in the trial. In a subsequent behavioral experiment (Experiment 2), the specific timing of interference was manipulated to further explore apparent differences in the temporal specificity of the effects. Subjects performed a delayed serial recall task while irrelevant information was imposed during specific trial stages: encoding, delay, or recall. Articulatory suppression was found to be most effectual when it coincided with item encoding, while both irrelevant speech and irrelevant nonspeech were most effectual when presented during the post-presentation delay. Taken together, these experiments provide convergent evidence for a dissociation of articulatory suppression from the two irrelevant sound conditions, but suggest that the effects of irrelevant speech and irrelevant nonspeech are functionally equivalent. This pattern of dissociation is predicted by the Embedded-Processes model (Cowan, 1995), but proves challenging to explain in the context of alternative theories

Space Efficient Breadth-First and Level Traversals of Consistent Global States of Parallel Programs

Enumerating consistent global states of a computation is a fundamental problem in parallel computing with applications to debug- ging, testing and runtime verification of parallel programs. Breadth-first search (BFS) enumeration is especially useful for these applications as it finds an erroneous consistent global state with the least number of events possible. The total number of executed events in a global state is called its rank. BFS also allows enumeration of all global states of a given rank or within a range of ranks. If a computation on n processes has m events per process on average, then the traditional BFS (Cooper-Marzullo and its variants) requires $\mathcal{O}(\frac{m^{n-1}}{n})$ space in the worst case, whereas ou r algorithm performs the BFS requires $\mathcal{O}(m^2n^2)$ space. Thus, we reduce the space complexity for BFS enumeration of consistent global states exponentially. and give the first polynomial space algorithm for this task. In our experimental evaluation of seven benchmarks, traditional BFS fails in many cases by exhausting the 2 GB heap space allowed to the JVM. In contrast, our implementation uses less than 60 MB memory and is also faster in many cases

NLC-2 graph recognition and isomorphism

NLC-width is a variant of clique-width with many application in graph algorithmic. This paper is devoted to graphs of NLC-width two. After giving new structural properties of the class, we propose a $O(n^2 m)$-time algorithm, improving Johansson's algorithm \cite{Johansson00}. Moreover, our alogrithm is simple to understand. The above properties and algorithm allow us to propose a robust $O(n^2 m)$-time isomorphism algorithm for NLC-2 graphs. As far as we know, it is the first polynomial-time algorithm.Comment: soumis \`{a} WG 2007; 12

Basic conceptual structures theory

Although the theory of Conceptual Structures is over 10 years old, basic notions (like canonical graphs) are far from settled and are subject to constant extensions and reformulations. However, most of these are done in an informal way, which doesn't help in clarifying the issues involved. It is our hope that this paper will provide a first step towards the complete and rigorous account of Conceptual Structures (CS) Theory, which is needed for ongoing standardization and implementation efforts. Towards that goal, we present formal definitions of some of the central notions of CS theory (type, referent, concept, relation, conceptual graph, canonical formation rules, canon, and canonical graph) in its simplest form, i.e. no contexts nor coreference links are allowed and referents must be individuals. We thereby introduce higher-order types in order to enable the use of conceptual graphs at the metalevel, the restriction operation of the canonical formation rules is extended to make use of the relation hierarchy, we show the relationship between denotation and conformity relation, and we give a rigorous meaning to the canonical basis, among other things

RDF to Conceptual Graphs Translations

International audienceIn this paper we will discuss two different translations between RDF (Resource Description Format) and Conceptual Graphs (CGs). These translations will allow tools like Cogui and Cogitant to be able to import and export RDF(S) documents. The first translation is sound and complete from a reasoning view point but is not visual nor a representation in the spirit of Conceptual Graphs (CGs). The second translation has the advantage of being natural and fully exploiting the CG features, but, on the other hand it does not apply to the whole RDF(S). We aim this paper as a preliminary report of ongoing work looking in detail at different pro and the cons of each approach

Representing First-Order Logic Using Graphs

Abstract. We show how edge-labelled graphs can be used to represent first-order logic formulae. This gives rise to recursively nested structures, in which each level of nesting corresponds to the negation of a set of existentials. The model is a direct generalisation of the negative application conditions used in graph rewriting, which count a single level of nesting and are thereby shown to correspond to the fragment ∃¬∃ of first-order logic. Vice versa, this generalisation may be used to strengthen the notion of application conditions. We then proceed to show how these nested models may be flattened to (sets of) plain graphs, by allowing some structure on the labels. The resulting formulae-as-graphs may form the basis of a unification of the theories of graph transformation and predicate transformation