90 research outputs found

    Fully Automatic Method for the Visual Acuity Estimation Using OCT Angiographies

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    [Abstract] In this work we propose the automatic estimation of the visual acuity of patients with retinal vein occlusion using Optical Coherence Tomography by Angiography (OCTA) images. To do this, we first extract the most relevant biomarkers in this imaging modality—area of the foveal avascular zone and vascular densities in different regions of the OCTA image. Then, we use a support vector machine to estimate the visual acuity. We obtained a mean absolute error of 0.1713 between the manual visual acuity measurement and the estimated, being considered satisfactory results.Centro de Investigación de Galicia; ED431G 2019/01Xunta de Galicia; DTS18/00136Ministerio de Ciencia, Innovación y Universidades; RTI2018-095894-B-I0

    Automatic Wide Field Registration and Mosaicking of OCTA Images Using Vascularity Information

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    [Abstract] Optical Coherence Tomography Angiography (OCTA) constitutes a novel ophthalmological image modality that is characterized for being a non-invasive capture technique that allows a profound analysis of the vascular characteristics of the eye fundus. Given the restricted field of view of the eye fundus that offers each scan, the specialists frequently capture several complementary images that may be simultaneously analyzed to offer a complete and accurate diagnosis of the patient. In this work, we propose a fully automatic method to register complementary OCTA images and provide compositions for the same patient, generating a wide field of representation that allows a simpler and more direct analysis than the traditional tedious manual procedures. To achieve this, we based our proposal in a robust combination of representative features that are filtered by an accurate identification of the main retinal vasculature. This way, given the characteristic high irregularity in the fundus of the OCTA images, we avoid many variable areas that may interfere in the registration process, restricting the analysis to the most representative and stable structure of this image modality, the main retinal vasculature. In particular, we use Speeded-Up Robust Features (SURF) algorithm to extract representative features in the main vascular region that is extracted using a method that combines the analysis of the Hessian matrix followed by an hysteresis threshold process. Then, using a K-NN model, we perform the registration of the resulting features from the different OCTA images to be analyzed. Finally, the Random sample consensus (RANSAC) method is exploited to produce the final target mosaic. The proposed method presented satisfactory results in the validation experiments, with accurate values for the MSE index of 1.2566 and 1.6725 pixels for the registration of paired images an mosaics, respectively.Xunta de Galicia; ED431G/01Xunta de Galicia; ED431C 2016-047This work is supported by the Instituto de Salud Carlos III, Government of Spain and FEDER funds of the European Union through the DTS18/00136 research projects and by the Ministerio de Economía y Competitividad, Government of Spain through the DPI2015-69948-R research project. Also, this work has received financial support from the European Union (European Regional Development Fund - ERDF) and the Xunta de Galicia, Centro singular de investigación de Galicia accreditation 2016-2019, Ref. ED431G/01; and Grupos de Referencia Competitiva, Ref. ED431C 2016-047

    The effects of teaching and assessment methods on academic performance: a study of an Operations Management course

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    Whether the use of more active teaching–learning methods has a positive impact on academic performance remains unanswered. This article seeks to contribute to the issue by conducting a study of an Operations Management course with almost 1000 students per year over three consecutive academic years. The study compares three scenarios with differing degrees of student involvement and Information Technology usage. The findings show no differences in terms of exam grades, but there is an increase in the percentage of passes in the most active scenario analysed, in which continuous assessment tests are used. Notwithstanding, student involvement in the optional assessable activities was found to be a significant factor for predicting the likelihood of passing the subject, especially when continuous assessment tests are used, since their grades show a higher correlation with exam grades

    Diabetic Macular Edema Characterization and Visualization Using Optical Coherence Tomography Images

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    [Abstract] Diabetic Retinopathy and Diabetic Macular Edema (DME) represent one of the main causes of blindness in developed countries. They are characterized by fluid deposits in the retinal layers, causing a progressive vision loss over the time. The clinical literature defines three DME types according to the texture and disposition of the fluid accumulations: Cystoid Macular Edema (CME), Diffuse Retinal Thickening (DRT) and Serous Retinal Detachment (SRD). Detecting each one is essential as, depending on their presence, the expert will decide on the adequate treatment of the pathology. In this work, we propose a robust detection and visualization methodology based on the analysis of independent image regions. We study a complete and heterogeneous library of 375 texture and intensity features in a dataset of 356 labeled images from two of the most used capture devices in the clinical domain: a CIRRUSTM HD-OCT 500 Carl Zeiss Meditec and 179 OCT images from a modular HRA + OCT SPECTRALIS® from Heidelberg Engineering, Inc. We extracted 33,810 samples for each type of DME for the feature analysis and incremental training of four different classifier paradigms. This way, we achieved an 84.04% average accuracy for CME, 78.44% average accuracy for DRT and 95.40% average accuracy for SRD. These models are used to generate an intuitive visualization of the fluid regions. We use an image sampling and voting strategy, resulting in a system capable of detecting and characterizing the three types of DME presenting them in an intuitive and repeatable way.Xunta de Galicia; ED431G 2019/01This research was funded by Instituto de Salud Carlos III, Government of Spain, DTS18/00136 research project; Ministerio de Ciencia, Innovación y Universidades, Government of Spain, RTI2018-095894-B-I00 research project, Ayudas para la formación de profesorado universitario (FPU), grant ref. FPU18/02271; CITIC, Centro de Investigación de Galicia ref. ED431G 2019/01, receives financial support from Consellería de Educación, Universidade e Formación Profesional, Xunta de Galicia, through the ERDF (80%) and Secretaría Xeral de Universidades (20%)

    A versatile approach to access trimetallic complexes based on trisphosphinite ligands

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    A straightforward method for the preparation of trisphosphinite ligands in one step, using only commercially available reagents (1,1,1-tris(4-hydroxyphenyl)ethane and chlorophosphines) is described. We have made use of this approach to prepare a small family of four trisphosphinite ligands of formula [CH3C{(C6H4OR2)3], where R stands for Ph (1a), Xyl (1b, Xyl = 2,6-Me2-C6H3), iPr (1c), and Cy (1d). These polyfunctional phosphinites allowed us to investigate their coordination chemistry towards a range of late transition metal precursors. As such, we report here the isolation and full characterization of a number of Au(I), Ag(I), Cu(I), Ir(III), Rh(III) and Ru(II) homotrimetallic complexes, including the structural characterization by X-ray diffraction studies of six of these compounds. We have observed that the flexibility of these trisphosphinites enables a variety of conformations for the different trimetallic species.European Research Council 756575Ministerio de Ciencia, Innovación y Universidades CTQ2017-92622-EX

    A Novel Automatic Method to Estimate Visual Acuity and Analyze the Retinal Vasculature in Retinal Vein Occlusion Using Swept Source Optical Coherence Tomography Angiography

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    [Abstract] The assessment of vascular biomarkers and their correlation with visual acuity is one of the most important issues in the diagnosis and follow-up of retinal vein occlusions (RVOs). The high workloads of clinical practice make it necessary to have a fast, objective, and automatic method to analyze image features and correlate them with visual function. The aim of this study is to propose a fully automatic system which is capable of estimating visual acuity (VA) in RVO eyes, based only on information obtained from macular optical coherence tomography angiography (OCTA) images. We also propose an automatic methodology to rapidly measure the foveal avascular zone (FAZ) area and the vascular density (VD) in the superficial and deep capillary plexuses in swept-source OCTA images centered on the fovea. The proposed methodology is validated using a representative sample of 133 visits of 50 RVO patients. Our methodology estimates VA with very high precision and is even more accurate when we integrate depth information, providing a high correlation index of 0.869 with the real VA, which outperforms the correlation index of 0.855 obtained when estimating VA from the data obtained by the semiautomatic existing method. In conclusion, the proposed method is the first computational system able to estimate VA in RVO, with the additional benefits of being automatic, less time-consuming, objective and more accurate. Furthermore, the proposed method is able to integrate depth information, a feature which is lacking in the existing method.Mutua Madrileña; 2017/365

    La influencia de la docencia en inglés en la movilidad académica y la proyección internacional del centro

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    El EEES, con la Declaración de Bolonia, tiene entre sus objetivos armonizar los distintos sistemas educativos de la UE y proporcionar una forma eficaz de intercambio entre sus estudiantes. La docencia en inglés en los centros de educación superior es un instrumento relevante para la movilidad de los estudiantes y la internacionalización de las universidades europeas. En este capítulo, desde la experiencia de la Subdirección de Relaciones Internacionales, se ponen de manifiesto los beneficios que la docencia en inglés proporciona a nuestros alumnos, profesores, y personal de administración, así como a la propia EUEE como Centro de Enseñanza de Educación Superior

    Las termas y el Suburbium marítimo de Baelo Claudia. Avance de un reciente descubrimiento

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    Entre los años 2010 y 2012, la Universidad de Cádiz y la Junta de Andalucía han desarrollado investigaciones arqueológicas en la zona extramuros de la ciudad hispanorromana, en el marco del Proyecto General de Investigación “La economía marítima y las actividades haliéuticas en Baelo Claudia”. Se presentan en esta sede los primeros resultados, que han permitido identificar la existencia de un suburbium occidental en la ciudad, entre el cauce del arroyo de las Villas, la playa y la necrópolis oeste, cuya existencia se ha podido confirmar por datos geofísicos y arqueológicos. En él han podido ser excavadas parcialmente unas estructuras que se han identificado con unas termas suburbanas, activas entre el s. II y el V d.C., habiéndose excavado una piscina del frigidarium y algunas estancias calefactadas, con hallazgos muy significativos como parte de la decoración marmórea y escultórica del complejo, que en época tardorromana fue amortizado intencionalmente por motivos posiblemente religiosos. Estos hallazgos son de gran interés, pues además de verificar la existencia de un segundo complejo balneario público en la ciudad plantean la importancia del poblamiento periurbano, una línea de investigación totalmente inédita hasta la fechaBetween the year 2010 and 2012, the University of Cadiz and the Regional Government (Junta de Andalucía) have developed archaeological activities in the zone outside the hispano-roman city, in the frame of the General Project of Research titled “The maritime economy and the halieutic activities in Baelo Claudia”. We are presenting in this paper the first results, which have allowed to identify the existence of a western suburbium outside the city, between the riverbed of the so called “arroyo de las Villas”, the beach and the western necropolis, whose remains have been confirmed by geophysical and archaeological techniques. Inside this area a few structures have been excavated, identified as a Roman baths complex, active from the 2nd up to the 5th century a.D. A big pool, part of the frigidarium and some heated rooms have been unearthed, with very significant findings as part of the marmoreal and sculptural decoration of the complex, which in late roman times was intentionally broken into pieces possibly by religious motives. These findings are of great interest, since beside confirming the existence of the second public thermae of the city they raise the importance of the peri-urban buildings, a new line of research up to dat

    Stability of breeding characters related with bread wheat quality in Southern Spain

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    In 1998 CIMMYT and Agrovegetal SA signed an agreement aimed at developing new wheat varieties adapted to agroclimatic conditions of Southern Spain. To select bread wheat cultivars appropriate for Andalusian market is important to meet high protein and bread making quality requirements. The stability of several characters related with bread quality of a set of five new varieties ('Escacena', 'Ecija', 'Olvera', 'Jerezano' and 'Vejer'), and three checks ('Yecora', 'Cartaya' and 'Pinzon') has been tested in samples collected from trials in quadrate lattice with three replicates in five locations of Andalusia during the 2000-2001 and 2001-2002 crop seasons. The quality testing and statistical analysis of the data were conducted at the Genetics Department of the University of Cordoba, showing that in these typical Mediterranean conditions the main part of quality parameters were highly influenced by the environment. The distribution of phenotypic variance showed that the three quality traits in which the genotype was the main factor of variation in the two-year analysis were SDSsedimentation, falling number, and alveograph-W. For the rest of traits the environment or the genotype x environment interaction explained, in at least one year, more than 50% of the observed variance
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