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Search Results: 1 - 10 of 22372 matches for " Roberto Hornero "
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Human exposition to non ionizing electromagnetic radiations. Legislation and base stations measurements Exposición humana a las radiaciones electromagnéticas no ionizantes. Legislación y medidas de estaciones base
Alonso Alonso Alonso,Ramón de la Rosa Steinz,Roberto Hornero Sánchez,Daniel Emilio Abásolo Baz
Revista de Salud Ambiental , 2004,
Abstract: This work deals about measurement procedures of non-ionizing radiations and their recorded levels in practice. The analyzed radiation sources cover the most common broadcasting media such as AM and FM transmissions and the GSM mobile telephony base stations. These sources currently radiate locations with high density of population. Spanish radiation level regulations are briefly described and some possible improvements are pointed out. The measurement results are discussed. Este trabajo trata sobre los procedimientos de medida de las radiaciones no ionizantes y sus niveles registrados en medidas reales. Las fuentes de radiación analizadas cubren los medios de radiodifusión más corrientes, tales como las transmisiones AM y FM y también las estaciones base de telefonía móvil GSM. Estas fuentes habitualmente radian sobre áreas con alta densidad de población. Se describe brevemente el marco legal que regula los niveles de radiación en Espa a y se se alan algunas posibles mejoras. Se valorarán los resultados encontrados en las medidas.
Reduced predictable information in brain signals in autism spectrum disorder
Carlos Gómez,Joseph T. Lizier,Michael Schaum,Patricia Wollstadt,Peter Uhlhaas,Christine M. Freitag,Roberto Hornero,Michael Wibral
Frontiers in Neuroinformatics , 2014, DOI: 10.3389/fninf.2014.00009
Abstract: Autism spectrum disorder (ASD) is a common developmental disorder characterized by communication difficulties and impaired social interaction. Recent results suggest altered brain dynamics as a potential cause of symptoms in ASD. Here, we aim to describe potential information-processing consequences of these alterations by measuring active information storage (AIS)—a key quantity in the theory of distributed computation in biological networks. AIS is defined as the mutual information between the past state of a process and its next measurement. It measures the amount of stored information that is used for computation of the next time step of a process. AIS is high for rich but predictable dynamics. We recorded magnetoencephalography (MEG) signals in 10 ASD patients and 14 matched control subjects in a visual task. After a beamformer source analysis, 12 task-relevant sources were obtained. For these sources, stationary baseline activity was analyzed using AIS. Our results showed a decrease of AIS values in the hippocampus of ASD patients in comparison with controls, meaning that brain signals in ASD were either less predictable, reduced in their dynamic richness or both. Our study suggests the usefulness of AIS to detect an abnormal type of dynamics in ASD. The observed changes in AIS are compatible with Bayesian theories of reduced use or precision of priors in ASD.
Assessment of Time and Frequency Domain Entropies to Detect Sleep Apnoea in Heart Rate Variability Recordings from Men and Women
Gonzalo C. Gutiérrez-Tobal,Daniel álvarez,Javier Gomez-Pilar,Félix del Campo,Roberto Hornero
Entropy , 2015, DOI: 10.3390/e17010123
Abstract: Heart rate variability (HRV) provides useful information about heart dynamics both under healthy and pathological conditions. Entropy measures have shown their utility to characterize these dynamics. In this paper, we assess the ability of spectral entropy (SE) and multiscale entropy (MsE) to characterize the sleep apnoea-hypopnea syndrome (SAHS) in HRV recordings from 188 subjects. Additionally, we evaluate eventual differences in these analyses depending on the gender. We found that the SE computed from the very low frequency band and the low frequency band showed ability to characterize SAHS regardless the gender; and that MsE features may be able to distinguish gender specificities. SE and MsE showed complementarity to detect SAHS, since several features from both analyses were automatically selected by the forward-selection backward-elimination algorithm. Finally, SAHS was modelled through logistic regression (LR) by using optimum sets of selected features. Modelling SAHS by genders reached significant higher performance than doing it in a jointly way. The highest diagnostic ability was reached by modelling SAHS in women. The LR classifier achieved 85.2% accuracy (Acc) and 0.951 area under the ROC curve (AROC). LR for men reached 77.6% Acc and 0.895 AROC, whereas LR for the whole set reached 72.3% Acc and 0.885 AROC. Our results show the usefulness of the SE and MsE analyses of HRV to detect SAHS, as well as suggest that, when using HRV, SAHS may be more accurately modelled if data are separated by gender.
Experiencia de ense?anza-aprendizaje: cambio de creencias y conductas en el manejo del agua de consumo
Rancich,Ana María; Ferrarini,Stella Ofelia; Palma,Néstor Hornero;
Revista de Saúde Pública , 1989, DOI: 10.1590/S0034-89101989000300002
Abstract: it was studied a change in the children's beliefs and behaviour with regard to their handling of drinking-water by using a teaching-learning experience by means of microscopic observation of polluted water. a structured pre-test and a post-test on problem-solving were administered to 63 6th and 7th grade elementary school children (28 boys and 35 girls). an of these children came from an underprivileged population in the north of buenos aires, argentina. their average age was of 12 years 8 months and sd = 1 year 1 month. each adequate aspect of their behaviour scored one point: hygiene and protection of containers for collection and storage, water treatment (boiling or the addition of chlorine) and the conservation period. the best beliefs ("to avoid the water contamination that produces illness") scored two points. the number of pupils that changed their beliefs and behaviour in the post-test was established and the significant difference was found by means of chi square test (x2). the children did not, in general, improve their behaviour or beliefs. they maintained adequate hygienic behaviour, but did not put into practice the protection of the containers used for the collection. behaviour regarding storage was still inadequate. the pupils did acquire correct behaviour as regards treatment by the boiling of water or the addition of chlorine (p < 0.01). however, the beliefs involved did not change. thirty percent of the pupils showed all the correct steps in the handling of drinking-water and 18% only failed to refer to the protection of the container in the post-test. the next educational actions must reinforce adequate hygienic behaviour and the addition of chlorine and change the inadequate behaviour regarding the protection of containers and the conservation period and sustain these procedures, with regard to contamination in general.
Bibliografía de revistas. Libros
Zamora, R.,Hidalgo, F. J.,Hornero, D.,Garrido Fernández, A.
Grasas y Aceites , 2003,
Abstract:
Prevalence and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus ST398 Resistant to Tetracycline at a Spanish Hospital over 12 Years
Mariana Camoez, Josep M. Sierra, Miquel Pujol, Ana Hornero, Rogélio Martin, M. Angeles Domínguez
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072828
Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) ST398, associated with livestock animals, was described in 2003 as a new lineage infecting or colonizing humans. We evaluated the prevalence and molecular characteristics of MRSA ST398 isolated in the Hospital Universitari de Bellvitge from January 2000 to June 2011. Tetracycline resistant (Tet-R) MRSA isolates from single patients (pts) were screened by SmaI-pulsed field gel electrophoresis (PFGE). Nontypable MRSA strains by SmaI (NTSmaI)-MRSA were further analysed by ApaI-PFGE, spa, SCCmec, agr, MLST typing, and by DNA microarray hybridization. Among 164 pts harboring Tet-R MRSA, NTSmaI-MRSA ST398-agrI was found in 33 pts (20%). Although the first pt was detected in 2003, 22/33 pts (67%) were registered in the 2010–2011 period. Ten pts (30%) were infected and cancer was the most frequent underlying disease. In one case, death was due to MRSA-ST398-related infection. Five pulsotypes (A–E) were detected using ApaI-PFGE, with type A accounting for 76% of the strains. The majority of the studied isolates presented spa type t011 (70%) and SCCmec type V (88%). One strain was spa negative both by PCR and microarray analysis. Forty-nine percent of the studied isolates showed resistance to 3 or more antibiotic classes, in addition to beta-lactams. Ciprofloxacin resistance was 67%. Tet-R was mediated by tet(M) and tet(K) in 26 isolates. All isolates lacked Panton-Valentine Leukocidin production, as well as other significant toxins. This study displays the molecular features of MRSA-ST398 clone and shows the increase in tetracycline resistance together with arise in MRSA-ST398 isolates infecting or colonizing patients in our clinical setting.
A Three-Dimensional Human Atrial Model with Fiber Orientation. Electrograms and Arrhythmic Activation Patterns Relationship
Catalina Tobón, Carlos A. Ruiz-Villa, Elvio Heidenreich, Lucia Romero, Fernando Hornero, Javier Saiz
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0050883
Abstract: The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block) and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: 1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, 2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, 3) double potentials related with wave fragmentations or blocking lines and 4) fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship between different atrial arrhythmic propagation patterns and the electrograms observed at more than 43000 points on the atrial surface.
Tratamiento digital de retinografías para detectar automáticamente lesiones asociadas con la retinopatía diabética
Sánchez Gutiérrez,CI; López Gálvez,MI; Hornero Sánchez,R; Poza Crespo,J;
Archivos de la Sociedad Espa?ola de Oftalmología , 2004, DOI: 10.4321/S0365-66912004001200009
Abstract: purpose: diabetic retinopathy is a leading cause of vision loss in developed countries. regular diabetic retinal eye screenings are needed to detect early signs of retinopathy, so that appropriate treatments can be rendered to prevent blindness. digital imaging is becoming available as a means of screening for diabetic retinopathy. however, with the large number of patients undergoing screenings, medical professionals require a tremendous amount of time and effort in order to analyse and diagnose the fundus photographs. our aim is to develop an automatic algorithm using digital image analysis for detecting these early lesions from retinal images. methods: an automatic method to detect hard exudates, a lesion associated with diabetic retinopathy, is proposed. the algorithm is based on their colour, using a statistical classification, and their sharp edges, applying an edge detector, to localise them. results: a sensitivity of 79.62% with a mean number of 3 false positives per image is obtained in a database of 20 retinal images with variable colour, brightness and quality. it can also be seen that the number of the false negative cases increases when the hard exudates were very close to the vessel tree. conclusion: the long term goal of the project is to automate the screening for diabetic retinopathy with retinal images. we have described the preliminary development of a tool to provide automatic analysis of digital fundus photographs to localise hard exudates. future work will address the issue of improving the obtained results and also will focus on detecting other lesions.
Universal multifractal description of an hourly rainfall time series from a location in southern Spain
GARCíA-MARíN, A. P;JIMéNEZ-HORNERO, F. J;AYUSO-MU?OZ, J. L;
Atmósfera , 2008,
Abstract: multifractal turbulence formalism has been used to perform an analysis for scales from 1 hour to almost 6 months of the time structure of the hourly rainfall series recorded during twenty-four years in córdoba, a location in southern spain. the parameters of the universal multifractal model were estimated and the theoretical moments scaling exponent function was obtained exhibiting an acceptable agreement with the empirical function for a range of moments. the universal multifractal model shown itself to be a suitable tool for describing the statistics of the rainfall series recorded in córdoba.
Tratamiento digital de retinografías para detectar automáticamente lesiones asociadas con la retinopatía diabética Retinal image analysis to detect lesions associated with diabetic retinopathy
CI Sánchez Gutiérrez,MI López Gálvez,R Hornero Sánchez,J Poza Crespo
Archivos de la Sociedad Espa?ola de Oftalmología , 2004,
Abstract: Objetivos: La retinopatía diabética es la causa más frecuente de ceguera en la población activa de los países industrializados. Para retrasar su evolución y evitar así la pérdida de visión, el mejor método de prevención es un seguimiento regular médico. Para ello, se utilizan las imágenes de fondo de ojo o retinografías. Sin embargo, debido al gran número de pacientes, se requiere mucho esfuerzo y tiempo para revisar todas las imágenes. El objetivo de este trabajo es desarrollar un método automático que ayude a detectar los primeros síntomas de la retinopatía diabética mediante un tratamiento digital de las retinografías. Métodos: El método expuesto en este artículo se centra exclusivamente en la detección de exudados duros, uno de los primeros síntomas de la retinopatía diabética. Su localización automática se basa en su color, usando clasificación estadística, y sus bordes definidos, mediante un filtro detector de bordes. Resultados: Aplicando el algoritmo propuesto a 20 retinografías de distinta calidad, iluminación y color, obtuvimos una sensibilidad de 79,62% con una media de 3 falsos positivos por imagen. El número de falso negativos aumentaba sobre todo cuando los exudados aparecían muy cerca de los vasos sanguíneos. Conclusión: El objetivo final de este proyecto es automatizar el seguimiento médico de la retinopatía diabética mediante el tratamiento digital de las retinografias de los pacientes. En esta primera etapa, se ha desarrollado una herramienta que permite la detección automática de una lesión asociada a esta enfermedad: los exudados duros. En futuros trabajos se pretende mejorar los resultados obtenidos y continuar con la localización de otras lesiones. Purpose: Diabetic retinopathy is a leading cause of vision loss in developed countries. Regular diabetic retinal eye screenings are needed to detect early signs of retinopathy, so that appropriate treatments can be rendered to prevent blindness. Digital imaging is becoming available as a means of screening for diabetic retinopathy. However, with the large number of patients undergoing screenings, medical professionals require a tremendous amount of time and effort in order to analyse and diagnose the fundus photographs. Our aim is to develop an automatic algorithm using digital image analysis for detecting these early lesions from retinal images. Methods: An automatic method to detect hard exudates, a lesion associated with diabetic retinopathy, is proposed. The algorithm is based on their colour, using a statistical classification, and their sharp edges, applying an edge detector, to lo
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