1,295 research outputs found

    Actividad físico-deportiva extraescolar en alumnos de primaria

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    En este estudio sociológico se plantea de forma imperiosa detectar las carencias en la actividad física extraescolar de la población escolar. En este sentido, nuestro estudio ahonda un poco más en la actividad físico-deportiva extraescolar en alumnos de Educación Primaria (6-12 años) de un distrito de Madrid (Carabanchel). Los resultados muestran como tan solo un 46,1% de las niñas realiza actividad físico-deportiva extraescolar. Estos porcentajes no son tan preocupantes en el caso de los niños (60,3%). Otro aspecto determinante en este trabajo ha sido el conocer el tiempo de práctica de los escolares que asisten a las actividades, siendo entre una y dos veces por semana el más determinante (92,1%). Teniendo en cuenta las modalidades deportivas y el tiempo de práctica aquí reflejados, padres y educadores debemos promover la práctica regular de ejercicio físico de nuestros niños, fomentando los efectos beneficiosos sobre la salud

    Sequences of purchases in credit card data reveal life styles in urban populations

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    Zipf-like distributions characterize a wide set of phenomena in physics, biology, economics and social sciences. In human activities, Zipf-laws describe for example the frequency of words appearance in a text or the purchases types in shopping patterns. In the latter, the uneven distribution of transaction types is bound with the temporal sequences of purchases of individual choices. In this work, we define a framework using a text compression technique on the sequences of credit card purchases to detect ubiquitous patterns of collective behavior. Clustering the consumers by their similarity in purchases sequences, we detect five consumer groups. Remarkably, post checking, individuals in each group are also similar in their age, total expenditure, gender, and the diversity of their social and mobility networks extracted by their mobile phone records. By properly deconstructing transaction data with Zipf-like distributions, this method uncovers sets of significant sequences that reveal insights on collective human behavior.Comment: 30 pages, 26 figure

    Un proyecto tutorado interdisciplinar en la formación de maestros. Resultados del proceso de evaluación formativa

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    En este documento presentamos el trabajo realizado en el curso actual con futuros maestros de Educación Primaria a través de una metodología activa, como son los proyectos tutorados. La experiencia docente aborda contenidos propios de la anatomía y fisiología del aparato digestivo en la asignatura Biología del Cuerpo Humano, así como las implicaciones en el aula de Educación Primaria como contenidos propios de la asignatura Ciencias Experimentales y su Didáctica. En la presente comunicación se expone la planificación y el desarrollo del proyecto tutorado diseñado, señalando algunos de los aspectos más relevantes como las competencias, los contenidos, el proceso y el sistema de evaluación. Finalmente se muestran los primeros resultados de su puesta en práctica

    Three-dimensional morphology and gene expression in the Drosophila blastoderm at cellular resolution II: dynamics.

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    BackgroundTo accurately describe gene expression and computationally model animal transcriptional networks, it is essential to determine the changing locations of cells in developing embryos.ResultsUsing automated image analysis methods, we provide the first quantitative description of temporal changes in morphology and gene expression at cellular resolution in whole embryos, using the Drosophila blastoderm as a model. Analyses based on both fixed and live embryos reveal complex, previously undetected three-dimensional changes in nuclear density patterns caused by nuclear movements prior to gastrulation. Gene expression patterns move, in part, with these changes in morphology, but additional spatial shifts in expression patterns are also seen, supporting a previously proposed model of pattern dynamics based on the induction and inhibition of gene expression. We show that mutations that disrupt either the anterior/posterior (a/p) or the dorsal/ventral (d/v) transcriptional cascades alter morphology and gene expression along both the a/p and d/v axes in a way suggesting that these two patterning systems interact via both transcriptional and morphological mechanisms.ConclusionOur work establishes a new strategy for measuring temporal changes in the locations of cells and gene expression patterns that uses fixed cell material and computational modeling. It also provides a coordinate framework for the blastoderm embryo that will allow increasingly accurate spatio-temporal modeling of both the transcriptional control network and morphogenesis

    Crowdsourcing malaria parasite quantification: an online game for analyzing images of infected thick blood smears

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    Background: There are 600,000 new malaria cases daily worldwide. The gold standard for estimating the parasite burden and the corresponding severity of the disease consists in manually counting the number of parasites in blood smears through a microscope, a process that can take more than 20 minutes of an expert microscopist’s time. Objective: This research tests the feasibility of a crowdsourced approach to malaria image analysis. In particular, we investigated whether anonymous volunteers with no prior experience would be able to count malaria parasites in digitized images of thick blood smears by playing a Web-based game. Methods: The experimental system consisted of a Web-based game where online volunteers were tasked with detecting parasites in digitized blood sample images coupled with a decision algorithm that combined the analyses from several players to produce an improved collective detection outcome. Data were collected through the MalariaSpot website. Random images of thick blood films containing Plasmodium falciparum at medium to low parasitemias, acquired by conventional optical microscopy, were presented to players. In the game, players had to find and tag as many parasites as possible in 1 minute. In the event that players found all the parasites present in the image, they were presented with a new image. In order to combine the choices of different players into a single crowd decision, we implemented an image processing pipeline and a quorum algorithm that judged a parasite tagged when a group of players agreed on its position. Results: Over 1 month, anonymous players from 95 countries played more than 12,000 games and generated a database of more than 270,000 clicks on the test images. Results revealed that combining 22 games from nonexpert players achieved a parasite counting accuracy higher than 99%. This performance could be obtained also by combining 13 games from players trained for 1 minute. Exhaustive computations measured the parasite counting accuracy for all players as a function of the number of games considered and the experience of the players. In addition, we propose a mathematical equation that accurately models the collective parasite counting performance. Conclusions: This research validates the online gaming approach for crowdsourced counting of malaria parasites in images of thick blood films. The findings support the conclusion that nonexperts are able to rapidly learn how to identify the typical features of malaria parasites in digitized thick blood samples and that combining the analyses of several users provides similar parasite counting accuracy rates as those of expert microscopists. This experiment illustrates the potential of the crowdsourced gaming approach for performing routine malaria parasite quantification, and more generally for solving biomedical image analysis problems, with future potential for telediagnosis related to global health challenges

    Precision Automation of Cell Type Classification and Sub-Cellular Fluorescence Quantification from Laser Scanning Confocal Images

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    While novel whole-plant phenotyping technologies have been successfully implemented into functional genomics and breeding programs, the potential of automated phenotyping with cellular resolution is largely unexploited. Laser scanning confocal microscopy has the potential to close this gap by providing spatially highly resolved images containing anatomic as well as chemical information on a subcellular basis. However, in the absence of automated methods, the assessment of the spatial patterns and abundance of fluorescent markers with subcellular resolution is still largely qualitative and time-consuming. Recent advances in image acquisition and analysis, coupled with improvements in microprocessor performance, have brought such automated methods within reach, so that information from thousands of cells per image for hundreds of images may be derived in an experimentally convenient time-frame. Here, we present a MATLAB-based analytical pipeline to 1) segment radial plant organs into individual cells, 2) classify cells into cell type categories based upon random forest classification, 3) divide each cell into sub-regions, and 4) quantify fluorescence intensity to a subcellular degree of precision for a separate fluorescence channel. In this research advance, we demonstrate the precision of this analytical process for the relatively complex tissues of Arabidopsis hypocotyls at various stages of development. High speed and robustness make our approach suitable for phenotyping of large collections of stem-like material and other tissue types

    Non-Amontons behavior of friction in single contacts

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    We report on the frictional properties of a single contact between a glassy polymer lens and a flat silica substrate covered either by a disordered or by a self-assembled alkylsilane monolayer. We find that, in contrast to common belief, the Amontons proportionality between frictional and normal stresses does not hold. Besides, we observe that the velocity dependence of the sliding stress is strongly sensitive to the structure of the silane layer. Analysis of the frictional rheology observed on both disordered and self-assembled monolayers suggests that dissipation is controlled by the plasticity of a glass-like interfacial layer in the former case, and by pinning of polymer chains on the substrate in the latter one.Comment: submitted to Eur. Phys. J.

    Atlas Toolkit: Fast registration of 3D morphological datasets in the absence of landmarks

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    Image registration is a gateway technology for Developmental Systems Biology, enabling computational analysis of related datasets within a shared coordinate system. Many registration tools rely on landmarks to ensure that datasets are correctly aligned; yet suitable landmarks are not present in many datasets. Atlas Toolkit is a Fiji/ImageJ plugin collection offering elastic group-wise registration of 3D morphological datasets, guided by segmentation of the interesting morphology. We demonstrate the method by combinatorial mapping of cell signalling events in the developing eyes of chick embryos, and use the integrated datasets to predictively enumerate Gene Regulatory Network states

    Osteochondroma of the mandibular condyle: Resection and reconstruction using vertical sliding osteotomy of the mandibular ramus

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    Osteochondroma is one of the most common benign bone tumours, although not in the craniofacial region. More than half of these appear in the coronoid process. It can appear on the mandibular condyle, especially in its medial half, and mainly affects women aged around forty years. We present the case of a 51-year-old woman with pain of several months? duration in the right temporomandibular joint (TMJ) and no other symptoms. Panoramic radiography showed an enlarged condyle with no subchondral cysts. Computed tomography showed a bony proliferation with benign signs and a scintigraphy revealed an increased uptake in the condyle. Due to the painful clinical symptoms, a surgical procedure using preauricular and retromandibular approaches was performed to excise the condyle. The resulting defect, which was 9 mm high, was reconstructed by means of a vertical sliding osteotomy of the mandibular ramus and two miniplates for osteosynthesis. Almost two years later, the patient is symptomfree and has a normal opening with no malocclusion or deviation in the opening pattern. We present and discuss different reconstruction options after condylectomy
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