359 research outputs found

    Banco de tiempo con oferta y demanda de servicios en una red P2P

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    La tecnología P2P desde su inicio ha vivido etapas de proliferación y otras en las que su avance se ha visto frenado. Las primeras redes P2P surgieron a finales del siglo XX y principalmente tenían como propósito el intercambio de ficheros entre diferentes puntos de la red. Aprovechando esta facilidad en los intercambios, los usuarios de estas aplicaciones las usaban para compartir de manera gratuita contenido sujeto a copyright, por ejemplo ficheros mp3, por lo que las entidades encargadas de defender la propiedad intelectual siempre han luchado por el cierre de estas redes. Por este motivo siempre se ha relacionado el concepto de piratería con la tecnología P2P, lo que ha provocado que en los últimos años no se hayan conseguido grandes avances en este campo para poder sacar provecho de los beneficios que una solución descentralizada ofrece. Lo que el presente documento pretende es promover la investigación de soluciones descentralizadas para aplicaciones de utilidad social, no destinadas al intercambio de contenido, mediante el análisis, diseño e implementación prototípica de un banco de tiempo sobre una red P2P. Se quieren buscar alternativas viables para esta aplicación escogida que se puedan trasladar a otras aplicaciones de otros ámbitos pero también sobre tecnología P2P. El presente proyecto es una continuación de otro TFG [1], el cual consistió en la construcción de un banco de tiempo P2P pero dejó unas partes incompletas e incluso algo incoherentes, y otras partes completamente sin desarrollar. Las correcciones aquí realizadas han mejorado el análisis y diseño de la parte de las transacciones de la aplicación respecto al proyecto previo, y como continuación de su desarrollo se ha realizado el análisis, diseño y una primera implementación del subsistema de oferta y demanda de servicios del banco de tiempo, permitiendo a potenciales consumidores de un servicio encontrar a proveedores del mismo. Para esta nueva parte de la aplicación, la cual no estaba previamente definida, se ha realizado un estudio amplio en el que se ha visto la necesidad de emplear una ontología dinámica, algo que es novedoso, para la cual se ha realizado casi todo el análisis y diseño de su uso en el banco de tiempo

    Analysis of segmentation ontology reveals the similarities and differences in connectivity onto L2/3 neurons in mouse V1

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    Quantitatively comparing brain-wide connectivity of different types of neuron is of vital importance in understanding the function of the mammalian cortex. Here we have designed an analytical approach to examine and compare datasets from hierarchical segmentation ontologies, and applied it to long-range presynaptic connectivity onto excitatory and inhibitory neurons, mainly located in layer 2/3 (L2/3), of mouse primary visual cortex (V1). We find that the origins of long-range connections onto these two general cell classes-as well as their proportions-are quite similar, in contrast to the inputs on to a cell type in L6. These anatomical data suggest that distal inputs received by the general excitatory and inhibitory classes of neuron in L2/3 overlap considerably

    Compact coplanar waveguide bandpass filter based on coupled S-shaped split ring resonators

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    This letter is focused on the application of coupled single-layer S-shaped split ring resonators (S-SRRs) to the design of highly compact bandpass filters in coplanar waveguide (CPW) technology. S-SRRs have been previously demonstrated as miniaturized resonators, particularly suited for applications in conjunction with coplanar line geometries. However, size reduction of CPW filters based on impedance inverters and S-SRRs is limited by the inverters. Therefore, this letter proposes an alternative geometry of CPW bandpass filters employing S-SRRs in a configuration based on the theory of coupled resonators. A highly compact third-order bandpass filter is designed using this principle, and the proposed approach is validated through experiment, demonstrating competitive filter performance achieved in an extremely small area

    Histologic and histomorphometric evaluation of a new bioactive liquid bbl on implant surface: a preclinical study in foxhound dogs

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    Background: bioactive chemical surface modifications improve the wettability and osse-ointegration properties of titanium implants in both animals and humans. The objective of this animal study was to investigate and compare the bioreactivity characteristics of titanium implants (BLT) pre‐treated with a novel bone bioactive liquid (BBL) and the commercially available BLT‐SLA active. Methods: forty BLT‐SLA titanium implants were placed in in four foxhound dogs. Animals were divided into two groups (n = 20): test (BLT‐SLA pre‐treated with BBL) and control (BLT‐SLA active) implants. The implants were inserted in the post extraction sockets. After 8 and 12 weeks, the animals were sacrificed, and mandibles were extracted, containing the implants and the surrounding soft and hard tissues. Bone‐to‐implant contact (BIC), inter‐thread bone area percentage (ITBA), soft tissue, and crestal bone loss were evaluated by histology and histomorphometry. Results: all animals were healthy with no implant loss or inflammation symptoms. All implants were clinically and histologically osseo‐integrated. Relative to control groups, test implants demon-strated a significant 1.5‐ and 1.7‐fold increase in BIC and ITBA values, respectively, at both assessment intervals. Crestal bone loss was also significantly reduced in the test group, as compared with controls, at week 8 in both the buccal crests (0.47 ± 0.32 vs 0.98 ± 0.51 mm, p < 0.05) and lingual crests (0.39* ± 0.3 vs. 0.89 ± 0.41 mm, p < 0.05). At week 12, a pronounced crestal bone loss improvement was observed in the test group (buccal, 0.41 ± 0.29 mm and lingual, 0.54 ± 0.23 mm). Tissue thickness showed comparable values at both the buccal and lingual regions and was significantly improved in the studied groups (0.82–0.92 mm vs. 33–48 mm in the control group). Conclusions: Relative to the commercially available BLT‐SLA active implants, BLT‐SLA pre‐treated with BBL showed improved histological and histomorphometric characteristics indicating a reduced titanium surface roughness and improved wettability, promoting healing and soft and hard tissue regeneration at the implant site.This research was funded by: Biointelligent Technology Systems SL, Barcelona, Spain

    Chemically defined conditions mediate an efficient induction of dental pulp pluripotent-like stem cells into hepatocyte-like cells

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    Liver diseases are major causes of morbidity and mortality. Dental pulp pluripotent-like stem cells (DPPSCs) are of a considerable promise in tissue engineering and regenerative medicine as a new source of tissue-specific cells; therefore, this study is aimed at demonstrating their ability to generate functional hepatocyte-like cells in vitro. Cells were differentiated on a collagen scaffold in serum-free media supplemented with growth factors and cytokines to recapitulate liver development. At day 5, the differentiated DPPSC cells expressed the endodermal markers FOXA1 and FOXA2. Then, the cells were derived into the hepatic lineage generating hepatocyte-like cells. In addition to the associated morphological changes, the cells expressed the hepatic genes HNF6 and AFP. The terminally differentiated hepatocyte-like cells expressed the liver functional proteins albumin and CYP3A4. In this study, we report an efficient serum-free protocol to differentiate DPPSCs into functional hepatocyte-like cells. Our approach promotes the use of DPPSCs as a new source of adult stem cells for prospective use in liver regenerative medicine.This study was funded by the Universitat Internacional de Catalunya (UIC), the Agència de Gestió d’Ajuts Universitaris i de Recerca, Generalitat de Catalunya project number (SGR 1060 for MA), the Kuwait Foundation for the Advancement of Sciences (KFAS), and the Dasman Diabetes Institute under project number (RA-2013-009 for AAM). CGR, EMS, and RNT were funded by the predoctoral grant Junior Faculty award from the Obra Social, 'la Caixa' Foundation, and UIC

    Accurate determination of marker location within whole-brain microscopy images

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    High-resolution whole-brain microscopy provides a means for post hoc determination of the location of implanted devices and labelled cell populations that are necessary to interpret in vivo experiments designed to understand brain function. Here we have developed two plugins (brainreg and brainreg-segment) for the Python-based image viewer napari, to accurately map any object in a common coordinate space. We analysed the position of dye-labelled electrode tracks and two-photon imaged cell populations expressing fluorescent proteins. The precise location of probes and cells were physiologically interrogated and revealed accurate segmentation with near-cellular resolution

    Dialogic literacy: Talking, reading and writing among primary school children

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    This study investigates the interplay between talk, reading and writing as 6th grade Mexican primary school children worked together, in small groups, on a psycholinguistic task that required them to read three related texts and then write an integrative summary. The study was conducted in the context of an educational program called ‘Learning Together’ (LT), which uses collaborative learning to enhance the development of children's oracy and literacy. Analyses of children's dialogues using the Ethnography of Communication in combination with a novel ‘Scheme for Educational Dialogue Analysis (SEDA)’ (Hennessy et al., 2016), revealed important improvements in effective oral communication - and specifically a shift towards the use of dialogic styles of interaction - between the children who participated in the LT program (as compared to those who did not). These improvements were accompanied by significantly higher quality integrative summaries, not only when children worked in small groups but also individually. The latter results indicate appropriation of sophisticated literacy abilities by the children. Further analyses of the relations among talk, reading and writing suggest that these processes are interwoven through subtle intertextual relations and support each other in a dynamic and iterative manner. We discuss the theoretical, methodological and practical relevance of the study.The work reported in this paper was supported by the Dirección General de Asuntos del Personal Académico of the National Autonomous University of Mexico (UNAM) (DGAPA-UNAM) (PAPIIT Project Number: IN303716). Professor Rojas-Drummond would like to thank the Faculty of Education at the University of Cambridge, UK for hosting her as Visiting Scholar while part of this manuscript was being prepared. Her visiting Scholarship was funded by the National Council of Science and Technology in Mexico (CONACYT Project Number: 160873). In addition, some of the methodological tools used in the study reported derived from a collaborative work carried out for a project entitled ‘A Tool for Analysing Dialogic Interactions in Classrooms’ (http://tinyurl.com/BAdialogue) funded through the British Academy International Partnership and Mobility Scheme (ref. RG66509), between January 2013–December 2015
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