220 research outputs found

    RDF-TR: Exploiting structural redundancies to boost RDF compression

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    The number and volume of semantic data have grown impressively over the last decade, promoting compression as an essential tool for RDF preservation, sharing and management. In contrast to universal compressors, RDF compression techniques are able to detect and exploit specific forms of redundancy in RDF data. Thus, state-of-the-art RDF compressors excel at exploiting syntactic and semantic redundancies, i.e., repetitions in the serialization format and information that can be inferred implicitly. However, little attention has been paid to the existence of structural patterns within the RDF dataset; i.e. structural redundancy. In this paper, we analyze structural regularities in real-world datasets, and show three schema-based sources of redundancies that underpin the schema-relaxed nature of RDF. Then, we propose RDF-Tr (RDF Triples Reorganizer), a preprocessing technique that discovers and removes this kind of redundancy before the RDF dataset is effectively compressed. In particular, RDF-Tr groups subjects that are described by the same predicates, and locally re-codes the objects related to these predicates. Finally, we integrate RDF-Tr with two RDF compressors, HDT and k2-triples. Our experiments show that using RDF-Tr with these compressors improves by up to 2.3 times their original effectiveness, outperforming the most prominent state-of-the-art techniques

    Prevalence and genetic diversity of Avipoxvirus in house sparrows in Spain

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    Avipoxvirus (APV) is a fairly common virus affecting birds that causes morbidity and mortality in wild and captive birds. We studied the prevalence of pox-like lesions and genetic diversity of APV in house sparrows (Passer domesticus) in natural, agricultural and urban areas in southern Spain in 2013 and 2014 and in central Spain for 8 months (2012±2013). Overall, 3.2% of 2,341 house sparrows visually examined in southern Spain had cutaneous lesions consistent with avian pox. A similar prevalence (3%) was found in 338 birds from central Spain. Prevalence was higher in hatch-year birds than in adults. We did not detect any clear spatial or temporal patterns of APV distribution. Molecular analyses of poxvirus-like lesions revealed that 63% of the samples were positive. Molecular and phylogenetic analyses of 29 DNA sequences from the fpv167 gene, detected two strains belonging to the canarypox clade (subclades B1 and B2) previously found in Spain. One of them appears predominant in Iberia and North Africa and shares 70% similarity to fowlpox and canarypox virus. This APV strain has been identified in a limited number of species in the Iberian Peninsula, Morocco and Hungary. The second one has a global distribution and has been found in numerous wild bird species around the world. To our knowledge, this represents the largest study of avian poxvirus disease in the broadly distributed house sparrow and strongly supports the findings that Avipox prevalence in this species in South and central Spain is moderate and the genetic diversity low.This study was funded by the Spanish Ministry of Science and Innovation (Project CGL2010-15734/BOS), the Spanish Ministry of Economy and Competitiveness (Project CGL2013-41642-P/BOS) and the Innovation and Development Agency of Andalusia (Spain) (P11-RNM-7038). Grants were awarded to JMP (Juan de la Cierva- JCI-2012-11868) and MAJM (FPIBES-2011-047609), Spanish Ministry of Economy and Competitiveness; RAJW (CEI-PICATA2012), CEI Campus of International Excellence; MM (FPU12/0568), Spanish Ministry of Education, Culture and Sports. RAJW was supported by the Craaford Foundation (grant 20160971) during the writing of this publication. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    A Transfer Hamiltonian Model for Devices Based on Quantum Dot Arrays

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    We present a model of electron transport through a random distribution of interacting quantum dots embedded in a dielectric matrix to simulate realistic devices. The method underlying the model depends only on fundamental parameters of the system and it is based on the Transfer Hamiltonian approach. A set of noncoherent rate equations can be written and the interaction between the quantum dots and between the quantum dots and the electrodes is introduced by transition rates and capacitive couplings. A realistic modelization of the capacitive couplings, the transmission coefficients, the electron/hole tunneling currents, and the density of states of each quantum dot have been taken into account. The effects of the local potential are computed within the self-consistent field regime. While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide

    Phase response analyses support a relaxation oscillator model of locomotor rhythm generation in Caenorhabditis elegans

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    Los circuitos neuronales se coordinan con los músculos y la retroalimentación sensorial para generar comportamientos motores adecuados al entorno de un animal. En C. elegans, los mecanismos por los cuales el circuito motor genera ondulaciones y las modula en función del entorno son en gran parte desconocidos. Analizamos cuantitativamente la locomoción de C. elegans durante el movimiento libre y durante la inhibición transitoria optogenética de los músculos. Los movimientos ondulatorios fueron altamente asimétricos con respecto a la duración de la flexión y desflexión durante cada ciclo. Las curvas de respuesta en fase inducidas por la breve inhibición optogenética de los músculos de la cabeza mostraron aumentos graduales y disminuciones rápidas en función de la fase en la que se aplicó la perturbación. Se desarrolló un modelo de oscilador de relajación basado en umbrales propioceptivos que cambian el momento del músculo activo, y se demostró que concuerda cuantitativamente con los datos del movimiento libre, las respuestas en fase y los resultados previos para la adaptación de la marcha a cargas mecánicas. Nuestros resultados sugieren un mecanismo neuromuscular subyacente a la generación del patrón motor de C. elegans dentro de un circuito compacto.Neural circuits coordinate with muscles and sensory feedback to generate motor behaviors appropriate to an animal's environment. In C. elegans, the mechanisms by which the motor circuit generates undulations and modulates them based on the environment are largely unclear. We quantitatively analyzed C. elegans locomotion during free movement and during transient optogenetic muscle inhibition. Undulatory movements were highly asymmetrical with respect to the duration of bending and unbending during each cycle. Phase response curves induced by brief optogenetic inhibition of head muscles showed gradual increases and rapid decreases as a function of phase at which the perturbation was applied. A relaxation oscillator model based on proprioceptive thresholds that switch the active muscle moment was developed and is shown to quantitatively agree with data from free movement, phase responses, and previous results for gait adaptation to mechanical loadings. Our results suggest a neuromuscular mechanism underlying C. elegans motor pattern generation within a compact circuit

    A Transfer Hamiltonian Model for Devices Based on Quantum Dot Arrays

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    We present a model of electron transport through a random distribution of interacting quantum dots embedded in a dielectric matrix to simulate realistic devices. The method underlying the model depends only on fundamental parameters of the system and it is based on the Transfer Hamiltonian approach. A set of noncoherent rate equations can be written and the interaction between the quantum dots and between the quantum dots and the electrodes is introduced by transition rates and capacitive couplings. A realistic modelization of the capacitive couplings, the transmission coefficients, the electron/hole tunneling currents, and the density of states of each quantum dot have been taken into account. The effects of the local potential are computed within the selfconsistent field regime. While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide

    Population-specific association of Clock gene polymorphism with annual cycle timing in stonechats

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    Timing is essential for survival and reproduction of organisms across the tree of life. The core circadian clock gene Clk has been implicated in annual timing and shows highly conserved sequence homology across vertebrates except for one variable region of poly Glutamine repeats. Clk genotype varies in some species with latitude, seasonal timing and migration. However, findings are inconsistent, difficult to disentangle from environmental responses, and biased towards high latitudes. Here we combine field data with a common-garden set up to study associations of Clk with latitude, migration and annual-cycle timing within the stonechat species complex with trans-equatorial distribution range. Including 950 individuals from nine populations with diverse migratory strategies. Gene diversity was lowest in resident African and Canary Island populations and increased with latitude, independently of migration distance. Repeat length and annual-cycle timing was linked in a population-specific way. Specifically, equatorial African stonechats showed delayed timing with longer repeat length for all annual-cycle stages. Our data suggest that at low latitudes with constant photoperiod, Clk genotype might orchestrate a range of consistent, individual chronotypes. In contrast, the influence of Clk on annual-cycle timing at higher latitudes might be mediated by its interactions with genes involved in (circadian) photoperiodic pathways

    Needle phobia: How to improve the child\u27s experience during blood drawing

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    Pediatric diseases, pain and hospitalization have an important impact on children and their families. This is especially significant when considering common invasive procedures, such as blood drawing. The objectives of the study were to assess the experience of children and families during the blood drawing procedure and suggest methods for improvement. The study was conducted in a children’s hospital in Barcelona, Spain, between 2018 and 2020. A mix-method design or combination of qualitative and quantitative methodologies was developed. We carried out a search of the literature, a design thinking approach, and a survey. Results from the qualitative approach identified areas for improvement, such as, the lack of information about the process of blood collection before testing, management of fear or pain, and characteristics of the physical space, among others. Regarding the quantitative approach, 277 persons (patients and families) were interviewed. And, although there were high levels of satisfaction among them about the blood drawing procedure, they also stressed the importance of the information received prior the test, the distraction techniques, and the physical space. From these results, we made different actions like information leaflets and fact sheets, distraction elements in the waiting room (wall vinyl, therapeutic dogs and clowns), and modification of the cabins. Although these results cannot be generalized to the population, they serve as an example of how to improve patient and family experience and include them in the decision-making process. In the current pandemic, further research should be done to adapt these results to the “new normal.” Experience Framework This article is associated with the Quality & Clinical Excellence lens of The Beryl Institute Experience Framework (https://www.theberylinstitute.org/ExperienceFramework). Access other PXJ articles related to this lens. Access other resources related to this lens
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