3,356 research outputs found
RDF-TR: Exploiting structural redundancies to boost RDF compression
The number and volume of semantic data have grown impressively over the last decade, promoting compression as an essential tool for RDF preservation, sharing and management. In contrast to universal compressors, RDF compression techniques are able to detect and exploit specific forms of redundancy in RDF data. Thus, state-of-the-art RDF compressors excel at exploiting syntactic and semantic redundancies, i.e., repetitions in the serialization format and information that can be inferred implicitly. However, little attention has been paid to the existence of structural patterns within the RDF dataset; i.e. structural redundancy. In this paper, we analyze structural regularities in real-world datasets, and show three schema-based sources of redundancies that underpin the schema-relaxed nature of RDF. Then, we propose RDF-Tr (RDF Triples Reorganizer), a preprocessing technique that discovers and removes this kind of redundancy before the RDF dataset is effectively compressed. In particular, RDF-Tr groups subjects that are described by the same predicates, and locally re-codes the objects related to these predicates. Finally, we integrate
RDF-Tr with two RDF compressors, HDT and k2-triples. Our experiments show that using RDF-Tr with these compressors improves by up to 2.3 times their original effectiveness, outperforming the most prominent state-of-the-art techniques
Global well-posedness of critical surface quasigeostrophic equation on the sphere
In this paper we prove global well-posedness of the critical
surface quasigeostrophic equation on the two dimensional sphere building
on some earlier work of the authors. The proof relies on an improving
of the previously known pointwise inequality for fractional laplacians as
in the work of Constantin and Vicol for the euclidean settingThis work has been partially supported by ICMAT Severo Ochoa project
SEV-2015-0554 and the MTM2011-2281 project of the MCINN (Spain
Uso de la placa Epiunión con injerto óseo en pseudoartrosis del cuello humeral
Las pseudoartrosis del cuello humeral son muy poco frecuentes. Cinco pacientes con esta patología fueron tratados mediante la placa Epiunion e injerto óseo. La consolidación de la fractura se consiguión en todos los casos. El tiempo medio de consolidación fue de 4,2 meses. El valor medio en el test de Constant fue de 95,4 puntos. La placa Epiunion con injerto óseo parece ser un buen método para el tratamiento de las pseudoartrosis del cuello humeral.Humeral neck nonunions are very uncommon. Five patients with humeral neck nonunion were treated using an Epiunion plate. A bone graft was added. Fracture healing was obtained in all cases. The mean healing time was 4,2 months. Le result was an average Constant store of 95,4 points. Epiunion plate with bone grafting appears to be a good method for the treatment of proximal humeral nonunions
Resultados a medio plazo del tratamiento quirúrgico de la rotura aguda del tendón de Aquiles
Se presenta un estudio descriptivo retrospectivo de 76 pacientes entre 21 y 75 años con rotura aguda del tendón de Aquiles, en el que se han valorado la epidemiología, el mecanismo lesional y los resultados del tratamiento mediante sutura término-terminal tipo Kessler e inmovilización rígida en yeso, comparándolo con los resultados de otras series de la literatura. Las principales conclusiones son que la rotura aguda del tendón de Aquiles es más frecuente en varones en la cuarta década de la vida y que el mecanismo lesional más frecuente es la práctica deportiva. El tratamiento mediante cirugía y posterior inmovilización con yeso ha dado buenos resultados. La edad, tiempo de descarga y la aparición de complicaciones se relacionan con peores resultados.Se presenta un estudio descriptivo retrospectivo de 76 pacientes entre 21 y 75 años con rotura aguda del tendón de Aquiles, en el que se han valorado la epidemiología, el mecanismo lesional y los resultados del tratamiento mediante sutura término-terminal tipo Kessler e inmovilización rígida en yeso, comparándolo con los resultados de otras series de la literatura. Las principales conclusiones son que la rotura aguda del tendón de Aquiles es más frecuente en varones en la cuarta década de la vida y que el mecanismo lesional más frecuente es la práctica deportiva. El tratamiento mediante cirugía y posterior inmovilización con yeso ha dado buenos resultados. La edad, tiempo de descarga y la aparición de complicaciones se relacionan con peores resultados
Spanish reference values for the Breastfeeding Self-Efficacy Scale-Short Form BSES-SF
Fundamento. Describir los valores de referencia para la versión española de la Escala de Autoeficacia para la Lactancia Materna en su versión reducida (BSES-SF), considerando las diferencias según la experiencia previa en lactancia y la paridad. Metodología. Estudio transversal realizado en cinco hospitales de Alicante y uno de la Región de Murcia, con una muestra accidental de 949 mujeres que ofrecieron lactancia materna en el posparto, sin problemas médicos, propios o del recién nacido, que dificultaran la lactancia. Se obtuvieron datos sociodemográficos, obstétricos y sobre autoeficacia materna para la lactancia mediante la escala BSES-SF. Se calcularon datos de tendencia central, dispersión y percentiles de las puntuaciones de la escala BSES-SF para generar valores de referencia para toda la muestra y según la paridad y experiencia previa. Resultados. El nivel de autoeficacia fue significativamente menor (p<0,001) entre las mujeres primíparas (media =47,67±11,03) o sin experiencia previa (media =47,30±11,18) que entre las multíparas (media =52,87±10,66) o con experiencia anterior (media =53,93±9,93). La puntuación de los percentiles P25 y P75 de la escala BSES-SF fue, respectivamente, para toda la muestra de 42 y 59; para las mujeres sin hijos o sin experiencia previos de 39 y 56; para madres con hijos de 46 y 61; y para las madres con experiencia previa de 47 y 62. Conclusión. Los percentiles específicos obtenidos, según la paridad o la experiencia previa, pueden considerarse como valores de referencia para comparar el nivel de autoeficacia de un caso dado, evaluar intervenciones educativas y planificar intervenciones de apoyo durante el posparto.Background. To describe the reference values for the Spanish version of the Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF), considering the differences according to parity and previous breastfeeding experience. Methods. Cross-sectional study in five hospitals in Alicante and one in Murcia, Spain, in a convenience sample of 949 in-hospital breastfeeding women, with no medical problems in the mothers or newborns hindering breastfeeding. Data on sociodemographic and obstetric variables, and on breastfeeding self-efficacy, using the BSES-SF, were collected. Central tendency, dispersion and percentile data were calculated to generate reference values for the entire sample, and by parity and previous experience. Results. The level of self-efficacy was significantly lower (p<0.001) among primiparous women (mean =47.67±11.03) or those without previous experience (mean =47.30±11.18) than among multiparas (mean =52.87±10.66) or women with previous experience (mean =53.93±9.93). The P25 and P75 percentiles for the BSES-SF were, respectively, 42 and 59 for the entire sample; 39 and 56 for women without children or without previous experience; 46 and 61 for mothers with children; and 47 and 62 for mothers with previous experience. Conclusions. The specific percentiles obtained by parity or previous experience should be considered the reference values for comparing the level of self-efficacy of a given case, and for evaluating educational interventions and planning postpartum support interventions.Este estudio recibió financiación del Ministerio de Ciencia e Innovación (nº de expediente PI09/90899)
Plántulas de Populus alba pretratadas con endófitos muestran una mayor tolerancia a Venturia tremulae
Algunos hongos endófitos parecen modular la respuesta de las plantas ante ataques de ciertos patógenos o insectos. En este trabajo se estudió la implicación de hongos endófitos de Populus alba en la tolerancia al patógeno necrotrofo Venturia tremulae, causante de la muerte de ramillos en especies de la sección Populus, siendo P. alba más tolerante que otras especies de la sección. Se evaluó in vitro el efecto de doce cepas de endófitos enfrentándolas al patógeno con el fin de seleccionar aquellas con mayor potencial de biocontrol. Se seleccionaron diez endófitos que fueron inoculados mediante solución esporal de una mezcla de todos ellos, de forma preventiva sobre plántulas de una savia de P. alba. Transcurridos 15 días, se inoculó al patógeno. Aunque en general los síntomas mostrados por las plantas fueron bajos, la mezcla de endófitos redujo la incidencia y severidad de los síntomas causados por el patógeno. Los resultados sugieren que los endófitos de P. alba limitarían los síntomas causados por el patógeno en este hospedante
A Compact Array Transducer for Full Calibration of Underwater Acoustic Detection Neutrino Telescopes
[EN] KM3NeT, the underwater neutrino telescope in the Mediterranean Sea, is a detector under construction. KM3NeT uses Digital Optical Modules (DOMs) to detect neutrinos but there will be a study about the viability to acoustic detection of neutrinos using mainly the acoustic sensors the telescope has for positioning purposes. For this, it is necessary to calibrate and test the acoustic response of the receivers in the detector to determine the sensitivity to detect the neutrino acoustic signal and discriminate it from the environmental background. In this work, the strategy for the calibration of the sensor system using a compact array using three steps (frequency, directivity and neutrino signal-like) is described. Moreover, some R&D activities and results about the second step (long parametric directive signals) are shown.Financial support of the Spanish Plan Estatal de Investigación, ref. PGC2018-096663-B-C43 (MICINN/FEDER)Ardid Ramírez, M.; Tortosa, DD.; Martínez Mora, JA. (2019). A Compact Array Transducer for Full Calibration of Underwater Acoustic Detection Neutrino Telescopes. IEEE. 591-595. https://doi.org/10.1109/IOTSMS48152.2019.8939244S59159
Configuración Software de la directividad de arrays lineales
A line array can be defined as a column of
loudspeakers that is designed so that these work together to achieve a higher directivity. This paper presents an application that enables a user to rotate the wavefront of uniform line arrays. Theoretical background and details of the
implementation are provided. The validity of the application is tested with measurements of the directivity that are also compared with simulations.Este trabajo ha sido financiado Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech y el grupo de investigación Aplicación de las Tecnologías de la Información y Comunicaciones (PAI TIC-208)
Effect of the end cross beams on the railway induced vibrations of short girder bridges
This work is devoted to the analysis of the railway-induced vertical vibrations of simplysupported double track bridges composed by pre-stressed concrete girder decks. Despite
the low torsional stiffness that this particular deck configuration exhibits, several structures of this type do exist in both conventional and high-speed railway lines in Spain.
Even though railway administrators recommend the construction of transverse or end
beams bracing the longitudinal girders at the supports in girder bridges, in several occasions these elements are not built in order to accelerate the construction process. The
aim of this study is to evaluate the beneficial effect of installing these transverse beams
on the vertical dynamic response of the aforementioned structures and to determine what
particular bridges are most affected by the presence of these elements. To this end, a
representative ensemble of girder bridges covering a range of span lengths L between 10
m and 25 m has been predimensioned and their dynamic behaviour has been predicted
by a finite element model that adopts common assumptions in engineering practice. Conclusions show that installing these elements is particularly relevant in the case of short
(10-12.5 m) oblique bridges with a low number of longitudinal girders for a particular
deck bending stiffness, leading to an important increase of the first torsion and first transverse bending natural frequencies and to a reduction of the structural response. Finally,
experimental measurements on a real bridge belonging to the Madrid-Sevilla high-speed
line are included in the final section to illustrate the theoretical derivations
Electromagnetic freezing: Effects of weak oscillating magnetic fields on crab sticks
Since the earlier 2000s, electromagnetic freezers have been sold all over the world. According to the manufacturers, the oscillating magnetic fields (OMFs) applied by these devices are capable of avoiding ice damage in frozen foods. To assess the effectiveness of OMFs in preserving food quality, we froze crab sticks in a commercial electromagnetic freezer, both with (<2 mT, 6-59 Hz) and without OMF application. Crab sticks were also frozen in a conventional freezer, both with static- and forced-air conditions, to compare electromagnetic freezing with conventional methods. After 24 h and 1, 3, 6, 9, and 12 months of storage, we did not find any effect of the OMFs on the drip loss, water-holding capacity, toughness, and whiteness of the crab sticks frozen in the electromagnetic device. Moreover, no advantage of electromagnetic freezing over air-blast freezing was detected at the conditions tested. More experiments at larger magnetic field strength and wider frequency ranges are needed to have a complete view of the potential effects of OMFs on food freezing.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project AGL2012-39756-C02-01. Antonio C. Rodríguez acknowledges the predoctoral contract BES-2013-065942 from MINECO, jointly financed by the European Social Fund, in the framework of the National Program for the Promotion of Talent and its Employability (National Sub-Program for Doctors Training).Peer reviewe
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