4,087 research outputs found

    Graph Element Networks: adaptive, structured computation and memory

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    We explore the use of graph neural networks (GNNs) to model spatial processes in which there is no a priori graphical structure. Similar to finite element analysis, we assign nodes of a GNN to spatial locations and use a computational process defined on the graph to model the relationship between an initial function defined over a space and a resulting function in the same space. We use GNNs as a computational substrate, and show that the locations of the nodes in space as well as their connectivity can be optimized to focus on the most complex parts of the space. Moreover, this representational strategy allows the learned input-output relationship to generalize over the size of the underlying space and run the same model at different levels of precision, trading computation for accuracy. We demonstrate this method on a traditional PDE problem, a physical prediction problem from robotics, and learning to predict scene images from novel viewpoints.Comment: Accepted to ICML 201

    Microblog retrieval challenges and opportunities

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    In recent years microblogging services have changed the way we communicate. Microblogs are a reduced version of web-blogs which are characterised by being just a few characters long. In the case of Twitter, messages known as \textit{tweets} are only 140 characters long, and are broadcasted from followees to followers organised as a social network. Microblogs such as tweets, are used to communicate up to the second information about any topic. Traffic updates, natural disaster reports, self-promotion, or product marketing are only a small portion of the type of information we can find across microblogging services. Most importantly, it has become a platform that has democratised the communication channels and empowered people into voicing their opinions. In fact, it is a very well known fact that the use Twitter amongst other social media services tilted the balance in favour of ex-president Obama when he was elected president of the USA in 2012. However, whilst the widespread use of microblogs has undoubtedly changed and shaped our current society, it is still very hard to effectively perform simple searches on such datasets due to the particular morphology of its documents. The limited character count and the ineffectiveness of state of the art retrieval models in producing relevant documents for queries, thus prompted TREC organisers to unite the research community into addressing these issues in 2011 during the first Microblog 2011 Track. This doctoral work is one of such efforts, and its focused on improving the access to microblog documents through ad-hoc searches. The first part of our work individually studies the behaviour of the state of the art retrieval models when utilised for microblog ad-hoc retrieval. First we contribute with the best configurations for each of the models studied. But more importantly, we discover how query term frequency and document length relates to the relevance of microblogs. As a result, we propose a microblog specific retrieval model, namely MBRM, which significantly outperforms the state of the art retrieval models described in this work. Furthermore we define an informativeness hypothesis in order to better understand the relevance of microblogs in terms of the presence of their inherent features or dimensions. We significantly improve the behaviour of a state of the art retrieval model by taking into consideration these dimensions as features into a linear combination re-ranking approach. Additionally we investigate the role that structure plays in determining the relevance of a microblog, by encoding the structure of relevant and non-relevant documents into two separate state machines. We then devise an approach to measure the similarity of an unobserved document towards each of these state machines, to then produce a score which is utilised for ranking. Our evaluation results demonstrate how the structure of microblogs plays a role in further differentiating relevant and non-relevant documents when ranking, by showing significantly improved results over a state of the art baseline. Subsequently we study the query performance prediction (QPP) task in terms of microblog ad-hoc retrieval. QPP represents the prediction of how well a query will be satisfied by a particular retrieval system. We study the performance of predictors in the context of microblogs and propose a number of microblog specific predictors. Finally our experimental evaluation demonstrates how our predictors outperform those in the literature in the microblog context. Finally, we address the ``vocabulary mismatch'' problem by studying the effect of utilising scores produced retrieval models as an ingredient in automatic query expansion (AQE) approaches based on pseudo relevance feedback . To this end we propose alternative approaches which do not rely directly on such scores and demonstrate higher stability when determining the most optimal terms for query expansion. In addition we propose an approach to estimate the quality of a term for query expansion. To this end we employ a classifier to determine whether a prospective query expansion term falls into a low, medium or high value category. The predictions performed by the classifier are then utilised to determine a boosting factor for such terms within an AQE approach. Then we conclude by proving that it is possible to predict the quality of terms by providing statistically enhanced results over an AQE baseline

    Validation of a Real-Time Capable Multibody Vehicle Dynamics Formulation for Automotive Testing Frameworks Based on Simulation

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    The growing functionalities implemented on vehicles have increased the importance of simulation in the design process. This complexity is mainly driven by the introduction of electrified powertrains, Advanced Driver Assistance Systems (ADAS) and Automated Driving Systems (ADS). Additionally, the automotive industry must reduce development times and cost, while keeping flexible development capabilities and fulfilling demanding regulation standards for safety-critical systems. Existing testing frameworks based on simulation implement typically analytical models to ensure real-time performance, and provide limited flexibility to perform Hardware in the Loop (HiL) setup based tests. In this work a vehicle modelling approach which guarantees high accuracy and real-time capabilities is proposed. Moreover, the proposed approach is validated firstly with real vehicle data, demonstrating that it can fairly reproduce the behaviour of the vehicle tested; and secondly, in a HiL setup to demonstrate the real-time execution capabilities of the approach

    Clinicopathological Parameters Related to Malignant Transformation of Oral Leukoplakia: A Meta-Analysis

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    Objective. To assess the clinical-pathological factors related to the malignant transformation of oral leukoplakia. Materials and Methods. A search for articles on malignant transformation factors related to oral leukoplakia was conducted in the following electronic databases: PubMed (MEDLINE, Cochrane Library), Web of Science (WoS) and Google Scholar. Thirty-seven articles with a low-moderate risk of bias according to the Newcastle-Ottawa methodological quality scale were included in this meta-analysis. The data were analyzed using the statistical programs RevMan 5.4 (The Cochrane Collaboration, Oxford, UK) and MedCalc Statistical Software version 16.4.3 (MedCalc Software Ltd. Ostend, Belgium) programs. The estimated prevalence was calculated according to DerSimonian and Laird random method. For dichotomous outcomes, the estimates of effects of an intervention were expressed as odds ratios (OR) using the Mantel-Haenszel (M-H) method with 95% confidence intervals. Results. The estimated global prevalence of malignant transformation of oral leukoplakia was 9.15%. The factors with the highest malignant transformation risk of oral leukoplakia were: non-homogeneous clinical types (OR: 5.41; p<0.001); leukoplakias with moderate-severe dysplasia (OR: 3.43; p<0.001); lesions located on the tongue and/or the floor of the mouth (OR: 3.19; p<0.001); leukoplakias in non-smokers (OR: 2.08; p<0.001) and lesions in women (OR: 1.73; p<0.001). In contrast, older age or regular alcohol intake were factors without significant influence (p>0.05).Conclusions. Non-homogenous oral leukoplakias and with moderate-severe dysplasia are those with the highest probability of malignant transformation

    Diseño sismorresistente de una vivienda multifamiliar empleando albañilería confinada con ladrillos ecológicos

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    La presente investigación cuyo objetivo fue determinar cómo influye el uso del ladrillo ecológico usando el sistema de albañilería confinada en el diseño sismorresistente de una vivienda multifamiliar obtuvo resultados favorables dado que los ensayos a los que se sometieron a estos ladrillos con residuos plásticos se obtuvieron valores de resistencia a la comprensión de 140.80 kg/cm2 , 148.1 kg/cm2, 146.8 kg/cm2 y 139.3 kg/cm2 en las proporciones del 0%, 10%, 20%, 30% resultados que lo ubican como un ladrillo del tipo I según la norma E070 de albañilería, valores que se lo ubican con excelente resistencia mecánica para la elaboración de muros estructural de albañilería confinada, desde el esquema de contribuir a la conservación del medio ambiente, la problemática del que hacer con los residuos plásticos y de los recursos no renovables el uso de este material ecológico contribuye a esos fines pues con el uso de este ladrillo ecológico se puede aminorar el impacto sobre el medio ambiente

    Spondyloarthropathies in autoimmune diseases and vice versa

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    Polyautoimmunity is one of the major clinical characteristics of autoimmune diseases (ADs). The aim of this study was to investigate the prevalence of ADs in spondyloarthropathies (SpAs) and vice versa. This was a two-phase cross-sectional study. First, we examined the presence of ADs in a cohort of patients with SpAs (). Second, we searched for the presence of SpAs in a well-defined group of patients with ADs () including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Sjögren’s syndrome (SS). Among patients with SpAs, ankylosing spondylitis was observed in the majority of them (55.6%). There were two patients presenting with SS in the SpA group (1.4%) and 5 patients with autoimmune thyroiditis (3.5%). The global prevalence of ADs in SpAs was 4.86%. In the ADs group, there were 5 patients with SpAs (0.46%). Our results suggest a lack of association between SpAs and ADs. Accordingly, SpAs might correspond more to autoinflammatory diseases rather than to ADs

    Factors Associated With Within-Herd Transmission of Serotype A Foot-and-Mouth Disease Virus in Cattle, During the 2001 Outbreak in Argentina: A Protective Effect of Vaccination

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    Argentina suffered an extensive foot-and-mouth disease (FMD) epidemic between July 2000 and January 2002, 3months after obtaining the official FMD-free without vaccination status conferred by the World Organization for Animal Health. This is one of the largest FMD epidemics controlled by implementation of a systematic mass vaccination campaign in an FMD-free country. In 2000, 124 herds were reported as FMD positive, 2394 herds in 2001 and one in January 2002; the total number of cattle herds in the country at that time was approximately 230000. Estimates of FMD transmission are important to understand the dynamics of disease spread and for estimating the value for the parameterization of disease transmission models, with the ultimate goals of predicting its spread, assessing and designing control strategies, conducting economic analyses and supporting the decision-making process. In this study, the within-herd coefficient of transmission, β, was computed for herds affected in the 2001 FMD epidemic and categorized as low or high based on the median value of β. A logistic regression model was fitted to identify factors significantly associated with high values of β. Results suggested that the odds of having a high within-herd transmission were significantly associated with time from initial herd infection to disease detection, date of report, vaccination, and time from initial herd infection to herd vaccination. Results presented in this study demonstrate, in quantifiable terms, the protective impact of vaccination in reducing FMD transmission in infected herds. These results will be useful for the parameterization of epidemiological models aimed at quantifying the impact of vaccination and for the design and implementation of FMD emergency vaccination strategies in face of an epidemic.Fil: Brito, B. P.. University of California at Davis; Estados Unidos. Universidad Nacional de Rosario; ArgentinaFil: Perez, Andres Maximiliano. University of California at Davis; Estados Unidos. Universidad Nacional de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cosentino, B.. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Rodriguez, L. L.. No especifíca;Fil: König, Guido Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentin

    EGF-Coupled Gold Nanoparticles Increase the Expression of CNPase and the Myelin-Associated Proteins MAG, MOG, and MBP in the Septal Nucleus Demyelinated by Cuprizone

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    ARTICULO DE ACCESO ABIERTOCurrent pharmacological therapies against demyelinating diseases are not quite satisfactory to promote remyelination. Epidermal growth factor (EGF) can expand the population of oligodendrocyte precursor cells (OPCs) that may help with the remyelination process, but its delivery into the injured tissue is still a biomedical challenge. Gold nanoparticles (GNPs) may be a useful tool for drug delivery into the brain. To evaluate remyelination in the septal nucleus, we administered intracerebral GNPs coupled with EGF (EGF–GNPs). C57BL6/J mice were demyelinated with 0.4% cuprizone (CPZ) and divided into several groups: Sham, Ctrl, GNPs, EGF, and EGF–GNPs. We evaluated the remyelination process at two time-points: 2 weeks and 3 weeks post-injection (WPI) of each treatment. We used the rotarod for evaluating motor coordination. Then, we did a Western blot analysis myelin-associated proteins: CNPase, MAG, MOG, and MBP. EGF–GNPs increase the expression of CNPase, MAG, and MOG at 2 WPI. At 3 WPI, we found that the EGF–GNPs treatment improves motor coordination and increases MAG, MOG, and MBP. EGF–GNPs enhance the expression of myelin-associated proteins and improve the motor coordination in mice. Thus, EGF-associated GNPs may be a promising pharmacological vehicle for delivering long-lasting drugs into the brain.S/

    Las NIIF como factor determinante para la globalización del mercado colombiano

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    — La globalización ha incidido de forma importante para la construcción de un nuevo mundo. Desde finales del siglo XX, la misma se ha encargado de romper paradigmas como lo era la hegemonía de los Estados en la regulación económica y las relaciones internacionales. La entrada en rigor de las Normas Internacionales de Información Financiera (NIIF), dieron paso a que nuevos actores como organismos internacionales, empresas e inversores, comenzaran a tener un rol más protagónico, gracias a la facilidad que brindaron al momento de garantizar la transparencia y libre información de los Estados que las adoptaron y pusieron en funcionamiento. El presente artículo busca identificar cuál es la incidencia que tienen las NIIF como un factor importante para la integración de Colombia en el proceso de globalización, en especial a partir de su ingreso a la Organización para la Cooperación y el Desarrollo Económico en el año 2020. Para cumplir dicho objetivo, se implementa una investigación con un método cualitativo, aplicando un procedimiento de tratamiento de información de segunda mano, que se sustenta en una constitución previa de las fuentes y su respectiva transcripción. Dicho proceso, permite vislumbrar las carencias que se presentan en Colombia frente a la debida aplicación de estas normas, que incidan directamente en la inmersión dentro del mercado mundial.Universidad Libre Seccional Pereira -- Facultad de Ciencias Económicas, Administrativas y Contables -- Contaduría PúblicaGlobalization has had an important impact on the construction of a new world. Since the late twentieth century, it has been responsible for breaking paradigms such as the hegemony of States in economic regulation and international relations. The entry into force of the International Financial Reporting Standards (IFRS), gave way to new actors such as international organizations, companies and investors, began to have a more leading role, thanks to the ease they provided when guaranteeing transparency and free information of the States that adopted and put them into operation. This article seeks to identify the impact of IFRS as an important factor for Colombia's integration into the globalization process, especially since its entry into the Organization for Economic Cooperation and Development in 2020. To meet this objective, an investigation is implemented with a qualitative method, applying a second-hand information processing procedure, which is based on a prior constitution of the sources and their respective transcription. This process allows us to glimpse the shortcomings that arise in Colombia in the face of the proper application of these standards, which directly affect the immersion within the world market
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