127 research outputs found

    The K Group Nearest-Neighbor Query on Non-indexed RAM-Resident Data

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    Data sets that are used for answering a single query only once (or just a few times) before they are replaced by new data sets appear frequently in practical applications. The cost of buiding indexes to accelerate query processing would not be repaid for such data sets. We consider an extension of the popular (K) Nearest-Neighbor Query, called the (K) Group Nearest Neighbor Query (GNNQ). This query discovers the (K) nearest neighbor(s) to a group of query points (considering the sum of distances to all the members of the query group) and has been studied during recent years, considering data sets indexed by efficient spatial data structures. We study (K) GNNQs, considering non-indexed RAM-resident data sets and present an existing algorithm adapted to such data sets and two Plane-Sweep algorithms, that apply optimizations emerging from the geometric properties of the problem. By extensive experimentation, using real and synthetic data sets, we highlight the most efficient algorithm

    Surface display of an anti-DEC-205 single chain Fv fragment in Lactobacillus plantarum increases internalization and plasmid transfer to dendritic cells in vitro and in vivo

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    BACKGROUND: Lactic acid bacteria (LAB) are promising vehicles for delivery of a variety of medicinal compounds, including antigens and cytokines. It has also been established that LAB are able to deliver cDNA to host cells. To increase the efficiency of LAB-driven DNA delivery we have constructed Lactobacillus plantarum strains targeting DEC-205, which is a receptor located at the surface of dendritic cells (DCs). The purpose was to increase uptake of bacterial cells, which could lead to improved cDNA delivery to immune cells. RESULTS: Anti-DEC-205 antibody (aDec) was displayed at the surface of L. plantarum using three different anchoring strategies: (1) covalent anchoring of aDec to the cell membrane (Lipobox domain, Lip); (2) covalent anchoring to the cell wall (LPXTG domain, CWA); (3) non-covalent anchoring to the cell wall (LysM domain, LysM). aDec was successfully expressed in all three strains, but surface location of the antibody could only be demonstrated for the two strains with cell wall anchors (CWA and LysM). Co-incubation of the engineered strains and DCs showed increased uptake when anchoring aDec using the CWA or LysM anchors. In a competition assay, free anti-DEC abolished the increased uptake, showing that the internalization is due to specific interactions between the DEC-205 receptor and aDec. To test plasmid transfer, a plasmid for expression of GFP under control of an eukaryotic promoter was transformed into the aDec expressing strains and GFP expression in DCs was indeed increased when using the strains producing cell-wall anchored aDec. Plasmid transfer to DCs in the gastro intestinal tract was also detected using a mouse model. Surprisingly, in mice the highest expression of GFP was observed for the strain in which aDec was coupled to the cell membrane. CONCLUSION: The results show that surface expression of aDec leads to increased internalization of L. plantarum and plasmid transfer in DCs and that efficiency depends on the type of anchor used. Interestingly, in vitro data indicates that cell wall anchoring is more effective, whereas in vivo data seem to indicate that anchoring to the cell membrane is preferable. It is likely that the more embedded localization of aDec in the latter case is favorable when cells are exposed to the harsh conditions of the gastro-intestinal tract

    Exploring the Use of Cytochrome Oxidase c Subunit 1 (COI) for DNA Barcoding of Free-Living Marine Nematodes

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    BackgroundThe identification of free-living marine nematodes is difficult because of the paucity of easily scorable diagnostic morphological characters. Consequently, molecular identification tools could solve this problem. Unfortunately, hitherto most of these tools relied on 18S rDNA and 28S rDNA sequences, which often lack sufficient resolution at the species level. In contrast, only a few mitochondrial COI data are available for free-living marine nematodes. Therefore, we investigate the amplification and sequencing success of two partitions of the COI gene, the M1-M6 barcoding region and the I3-M11 partition.MethodologyBoth partitions were analysed in 41 nematode species from a wide phylogenetic range. The taxon specific primers for the I3-M11 partition outperformed the universal M1-M6 primers in terms of amplification success (87.8% vs. 65.8%, respectively) and produced a higher number of bidirectional COI sequences (65.8% vs 39.0%, respectively). A threshold value of 5% K2P genetic divergence marked a clear DNA barcoding gap separating intra- and interspecific distances: 99.3% of all interspecific comparisons were >0.05, while 99.5% of all intraspecific comparisons were <0.05 K2P distance.ConclusionThe I3-M11 partition reliably identifies a wide range of marine nematodes, and our data show the need for a strict scrutiny of the obtained sequences, since contamination, nuclear pseudogenes and endosymbionts may confuse nematode species identification by COI sequence

    Live Coding, Live Notation, Live Performance

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    This paper/demonstration explores relationships between code, notation including representation, visualisation and performance. Performative aspects of live coding activities are increasingly being investigated as the live coding movement continues to grow and develop. Although live instrumental performance is sometimes included as an accompaniment to live coding, it is often not a fully integrated part of the performance, relying on improvisation and/or basic indicative forms of notation with varying levels of sophistication and universality. Technologies are developing which enable the use of fully explicit music notations as well as more graphic ones, allowing more fully integrated systems of code in and as performance which can also include notations of arbitrary complexity. This itself allows the full skills of instrumental musicians to be utilised and synchronised in the process. This presentation/demonstration presents work and performances already undertaken with these technologies, including technologies for body sensing and data acquisition in the translation of the movements of dancers and musicians into synchronously performable notation, integrated by live and prepared coding. The author together with clarinetist Ian Mitchell present a short live performance utilising these techniques, discuss methods for the dissemination and interpretation of live generated notations and investigate how they take advantage of instrumental musicians’ training-related neuroplasticity skills

    Enhancing Ueff in oxime-bridged [MnIII 6LnIII 2] hexagonal prisms

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    El pdf del artículo es la versión post-print.-- et al.The first 3d-4f clusters built using derivatised salicylaldoximes (R-saoH2) describe unusual hexagonal prisms. Replacement of the paramagnetic Gd(iii) ions with diamagnetic Ln(iii) ions allows for a more thorough understanding of the magnetic properties, whilst replacement with Tb(iii) doubles Ueff. © 2011 The Royal Society of Chemistry.This work was supported by the Leverhulme Trust (EKB) and the Spanish MICINN for contracts MAT2009-13977-C03 and CSD2007-00010 (ME).Peer Reviewe

    Utilisation des dispositifs à transfert de charges en traitement analogique du signal

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    Les dispositifs à transfert de charges (DTC) sont des dispositifs analogiques. Qu'ils soient analysés sous forme de ligne à retards ou de registre à décalage, ils constituent une mémoire analogique où sont stockés autant d'échantillons d'un signal, qu'ils comportent d'étages. Leur comportement est à caractériser autant par les concepts classiques analogiques : niveaux de signal et de bruit, distortion, bande passante ; que ceux caractéristiques des mémoires : durée de mémorisation et fréquence de sortie. La technologie de leur réalisation est entièrement compatible avec celle des circuits à transistors MOS. Les circuits que nous présentons, associent DTC et circuits périphériques analogiques. Les résultats obtenus sur cette génération de circuits peuvent se résumé à : . dynamique 60dB . distortion 1/100 . fréquence de transfert maximale 200KHz . bande passante 20KHz . impédance de sortie 10 KΩ. Ces circuits sont des véhicules de test, tant en ce qui concerne le fonctionnement analogique du UTC que de son association avec une circuiterie analogique MOS. A partir de ces résultats préliminaires, nous commençons l'analyse de l'impact de ces concepts de fonctionnement, sur ce que serait le calcul d'une transformée de Fourier, d'un produit de convolution, d'une fonction de corrélation au moyen de dispositifs entièrement intégrés mettant en oeuvre DTC et circuits périphériques à transistors MOS
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