160 research outputs found
Real-time detection, location, and measurement of geoeffective stellar flares from Global Navigation Satellite System Data: new technique and case studies
An alternative approach to detect solar flares and quantify the associated extreme ultraviolet (EUV) solar flux rate was introduced in this journal by the authors: Global Navigation Satellite Systems Solar FLAre Indicator (GSFLAI) was founded on the dependence of the sudden electron content increase of the Earth ionosphere versus the angle regarding the flare source, the Sun, given by a simple but accurate first-principles-based model. Such overionization is directly measured from the dual-frequency phase measurements gathered from hundreds of worldwide permanent receivers of the Global Navigation Satellite Systems, GNSS (like the Global Positioning System GPS), working many of them in real time. In this work we generalize GSFLAI for the very challenging scenario of stellar superflares, with a much weaker expected geoeffectiveness on the Earth ionosphere, making it difficult to distinguish its potential footprint regarding conventional ionospheric variability sources. Indeed, we will show that, unlike GSFLAI for solar flares, the new algorithm presented here (Blind GNSS search of Extraterrestrial EUV Sources [BGEES]) is able to detect EUV flares without the previous knowledge of the position of the source, which is also simultaneously estimated, providing an additional quality check of the detection. It will be first assessed with several case studies of solar flares of different intensities analyzed previously with GSFLAI. Finally, by focusing on the night hemisphere to avoid the Sun's larger effect on the ionosphere, the detection and location with BGEES of two recent stellar superflares, Proxima Centauri (18 March 2016, 08:32UT) and NGTS J121939.5-355557 (1 February 2016, 04:00UT), are presented, strongly suggesting the extension and applicability of the new technique, also in real time.Peer ReviewedPostprint (published version
Assessment and risk prediction of frailty using texture-based muscle ultrasound image analysis and machine learning techniques
[EN] The purpose of this study was to evaluate texture-based muscle ultrasound image analysis for the assessment and risk prediction of frailty phenotype. This retrospective study of prospectively acquired data included 101 participants who underwent ultrasound scanning of the anterior thigh. Participants were subdivided according to frailty phenotype and were followed up for two years. Primary and secondary outcome measures were death and comorbidity, respectively. Forty-three texture features were computed from the rectus femoris and the vastus intermedius muscles using statistical methods. Model performance was evaluated by computing the area under the receiver operating characteristic curve (AUC) while outcome prediction was evaluated using regression analysis. Models developed achieved a moderate to good AUC (0.67 <= AUC <= 0.79) for categorizing frailty. The stepwise multiple logistic regression analysis demonstrated that they correctly classified 70-87% of the cases. The models were associated with increased comorbidity (0.01 <= p <= 0.18) and were predictive of death for pre-frail and frail participants (0.001 <= p <= 0.016). In conclusion, texture analysis can be useful to identify frailty and assess risk prediction (i.e. mortality) using texture features extracted from muscle ultrasound images in combination with a machine learning approach.This work was supported by the following grants: Grant PID2020-113839RB-I00 funded by MCIN/AEI/10.13039/501100011033 to C.B. DM acknowledges financial support from the Conselleria d ' Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana (grants AEST/2018/021 and AEST/2019/037) .Mirón-Mombiela, R.; Ruiz-España, S.; Moratal, D.; Borrás, C. (2023). Assessment and risk prediction of frailty using texture-based muscle ultrasound image analysis and machine learning techniques. Mechanisms of Ageing and Development. 215. https://doi.org/10.1016/j.mad.2023.11186021
Segunda campaña de excavación en el asentamiento ibérico final de la Casa de la Cabeza (Requena, València)
Second report about the excavations in Casa de la Cabeza, an iberian rural settlement (IInd century BC)
Stiffness variation of porous titanium developed using space holder method
The excellent properties of Ti have resulted in its generalised use for bone implants. However, Ti is very stiff in comparison with human cortical bone, and this creates problems of bone weakening and loosening of the implant. This article discusses the mechanical properties (flexural and compressive strength, and stiffness) of porous Ti-6Al-4V specimens developed using the space holder method. These properties are examined relative to the production process parameters: compacting pressure and sintering time, as well as temperature, and the addition of spacer and its particle size. It is seen that when spacer is added, compressive strength decreases with the application of compacting pressure and that these are the most influential parameters. The developed pieces show a closed and unconnected porosity. Small additions of spacer (25 vol.-%) reduce stiffness to around half of that shown by the solid material, and the resulting pieces are strong enough to be used as bone substitute. © 2011 Institute of Materials, Minerals and Mining.The authors wish to thank the Spanish Ministry of Science and Innovation for the support received under project no. PET2008_0158_02. The translation of this article was funded by the Universidad Politecnica de Valencia.Reig Cerdá, L.; Amigó Borrás, V.; Busquets Mataix, DJ.; Calero, JA. (2011). Stiffness variation of porous titanium developed using space holder method. Powder Metallurgy. 54(3):389-392. https://doi.org/10.1179/003258910X12707304455068S389392543RYAN, G., PANDIT, A., & APATSIDIS, D. (2006). Fabrication methods of porous metals for use in orthopaedic applications. Biomaterials, 27(13), 2651-2670. doi:10.1016/j.biomaterials.2005.12.002in ‘ASM handbook’, Vol. 2, ‘Properties and selection: nonferrous alloys and special-purpose materials’, 1170; 1990, Materials Park, OH, ASM International.Asaoka, K., & Kon, M. (2003). Sintered Porous Titanium and Titanium Alloys as Advanced Biomaterials. Materials Science Forum, 426-432, 3079-3084. doi:10.4028/www.scientific.net/msf.426-432.3079Niinomi, M. (2008). Mechanical biocompatibilities of titanium alloys for biomedical applications. Journal of the Mechanical Behavior of Biomedical Materials, 1(1), 30-42. doi:10.1016/j.jmbbm.2007.07.001Rack, H. J., & Qazi, J. I. (2006). Titanium alloys for biomedical applications. Materials Science and Engineering: C, 26(8), 1269-1277. doi:10.1016/j.msec.2005.08.032Köhl M, Bram M, Buckremer HP, Stöver D: Proc. Conf. Euro PM2007, Toulouse, France, October 2007, European Powder Metallurgy Association, 129–134.Bram M, Bogdanski SH, Koller M, Buchkremer HP, Stover D: Proc. Conf. Euro PM2005, Prague, Czech Republic, October 2005, European Powder Metallurgy Association, 517–522.Reig L, Amigó V, Busquets D, Salvador MD, Calero JA: Proc. Conf. Sintering 2008, La Jolla, CA, USA, November 2008, American Ceramic Society. 273–282.Degischer, H., & Kriszt, B. (Eds.). (2002). Handbook of Cellular Metals. doi:10.1002/3527600558ComÃn M, Peris JL, Prat JM, Decoz JR, Vera PM, JV: Hoyos: ‘Biomecánica de la fractura ósea y técnicas de reparación’, 66–69; 1999, Valencia, Publicaciones UPV.Gibson LJ, Ashby MF: ‘Cellular solids: structure and properties’, 175–231; 1999, Cambridge, Cambridge University Press.Making metal foams. (2000). Metal Foams, 6-23. doi:10.1016/b978-075067219-1/50004-0Esen, Z., & Bor, Åž. (2007). Processing of titanium foams using magnesium spacer particles. Scripta Materialia, 56(5), 341-344. doi:10.1016/j.scriptamat.2006.11.010Leyens, C., & Peters, M. (Eds.). (2003). Titanium and Titanium Alloys. doi:10.1002/3527602119Lütjering G, Williams JC: ‘Titanium’, 2nd edn, 13–51; 2007, Berlin, Springer, Engineering Materials and Processes
Tercera campaña de excavación en el asentamiento ibérico final de La Casa de la Cabeza (Requena, València)
Preliminary report
Analysis of the corner kicks in the World Cup Korea and Japan 2002. Differences between the corner kicks in the first or in the second half of the match
El objetivo del presente trabajo es valorar si existen diferencias
entre los corners lanzados en la primera o en la segunda parte de
un partido. Se analizaron 486 corners en 50 partidos del Mundial
de Corea y Japón 2002. La modalidad de corner más utilizada es
a pie cambiado, con rosca interna y al centro. Con relación a la
eficacia, tan sólo el 21,81% de los lanzamientos finalizan con tiro
a puerta, de los cuales el 12,96% finalizan con un remate fuera
de la porterÃa y el 8,85% con un tiro entre los tres palos y tan
sólo el 2,47% finalizan en gol. No se aprecian diferencias significativas
entre los lanzamientos analizados en la primera y la segunda
parte.Actividad FÃsica y Deport
Rethinking the Xylella fastidiosa scenario in the Balearic Islands: what epidemiological, phylogenetic and dendrochronological data tell us
Trabajo presentado en la 2nd European conference on Xylella fastidiosa (how research can support solutions), celebrada en Ajaccio el 29 y 30 de octubre de 2019.The emergence of Xylella fastidiosa(Xf) in Europe has been dealt as relatively recent introductions from the American continent. While this seems accurate for highly virulent genotypes such as thestrain currently causing the quick olive decline syndrome in Apulia since ca. 2013, less virulent Xf genotypes might have gone undetected for a long time, being confused with drought or fungal disease symptoms under Mediterranean climatic conditions. Indeed, the current widespread incidence and severity of the Pierce’s disease (PD) and Almond Leaf Scorch Disease (ALSD) in Mallorca Island can only be understood in this context of a 20-year introduction scenario. Our current epidemiological, phylogenetic anddendrochronological data onXf strains belonging to subsp. fastidiosaST1, and Xf subsp. multiplexST81, causing Pierce’s disease (PD) and ALSD, respectively, strongly suggest that they were overlooked for decades. Both subspecies were very likely transported from California to Mallorca with infected almond scions around 1995 and subsequently spread throughout the island by the local vector Philaenus spumarius. Our phylogenetic analysis based on WGS of isolates of both subspecies from Mallorca supports their Californian origin. Congruent with this, Xf DNA was consistently detected in the growing rings of infected almond trees from 2006 to the present and occasionally as far back as 1998. In the main focus in Son Carrió more than 50% of the almond trees diedand 90% of trees showed symptoms compatible with ALSD in 2012, but the aetiology of this problem was attributed to fungal trunk diseases, drought or field abandonment. We hypothesise that during the last 20 years, Xf subsp. multiplexST81 isolates have adapted to wild olive trees, widespread on the island, causing a mild dieback, and later on reaching the island of Menorca very likely on infected P. spumariustransported as a hitchhiker on ships moving between the islands.This research was funded by project E-RTA2017-00004-C06 from AEI-INIA Spain and FEDER and received financial support from the Ministry of Agriculture, Fishery and Food (Dirección General de la Sanidad de la Producción Agrà ria) of Spain and from ‘Govern de les Illes Balears’
A Sequentially Consistent Multiprocessor Architecture for Out-of-Order Retirement of Instructions
Out-of-order retirement of instructions has been shown to be an effective technique to increase the number of in-flight instructions. This form of runtime scheduling can reduce pipeline stalls caused by head-of-line blocking effects in the reorder buffer (ROB). Expanding the width of the instruction window can be highly beneficial to multiprocessors that implement a strict memory model, especially when both loads and stores encounter long latencies due to cache misses, and whose stalls must be overlapped with instruction execution to overcome the memory latencies. Based on the Validation Buffer (VB) architecture (a previously proposed out- of-order retirement, checkpoint-free architecture for single processors), this paper proposes a cost-effective, scalable, out-of-order retirement multiprocessor, capable of enforcing sequential consistency without impacting the design of the memory hierarchy or interconnect. Our simulation results indicate that utilizing a VB can speed up both relaxed and sequentially consistent in-order retirement in future multiprocessor systems by between 3 and 20 percent, depending on the ROB size.Ubal Tena, R.; Sahuquillo Borrás, J.; Petit MartÃ, SV.; López RodrÃguez, PJ.; Kaeli, D. (2012). A Sequentially Consistent Multiprocessor Architecture for Out-of-Order Retirement of Instructions. IEEE Transactions on Parallel and Distributed Systems. 23(8):1361-1368. doi:10.1109/TPDS.2011.255S1361136823
Development of a biocomposite based on green polyethylene biopolymer and eggshell
In this investigation a fully biobased composite material has been obtained using a biobased polyethylene obtained from sugar cane as matrix and eggshell (ES) as filler. ES was studied in order to replace mineral carbonate calcium as polymer filler, which is commonly used. In order to do this the ES has been chemically modified and then its potential for the development of a biocomposite was evaluated. The filler adhesion to the polymer matrix has been improved using titanate particle treatment which has been chosen between silane and zirconate. The use of titanate as coupling agent enlarges the range of operating temperatures and also improves the interfacial bonding as it is displayed in impact fracture surface. Mechanical, thermal and rheological analysis were carried out in order to analyze the effect of the modified ES loading percentage. Thermal analysis showed a proportional effect of the filler load over the degradation temperature and an inversely effect over the enthalpy. Effect of the modified ES content on mechanical properties of PE/ES was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical properties of bio PE, improving stiffness, hardness, flexural and tensile modulus. The amount of filler increases the viscosity, this fact specially hinders the processing processes which work with low shear rates. (C) 2014 Elsevier Ltd. All rights reserved.This study has been funded by the "Conselleria d'Educacio, Cultura i Esport" - Generalitat Valenciana (Reference number: GV/2014/008). The authors wish to thank to "Confiteria El Tunel" and to "Dulces Hispania" to collaborate in providing the eggshell.Boronat Vitoria, T.; Fombuena Borrás, V.; GarcÃa Sanoguera, D.; Sánchez Nacher, L.; Balart Gimeno, RA. (2015). Development of a biocomposite based on green polyethylene biopolymer and eggshell. Materials and Design. 68:177-185. doi:10.1016/j.matdes.2014.12.027S1771856
Transformation of the mathematics teacher's knowledge about argumentation tasks : an own analysis exercise.
En este documento presentamos el reporte de una investigación cuyo propósito es caracterizar la transformación del conocimiento didáctico – matemático de los dos autores de esta tesis, respecto al diseño de tareas de argumentación, cuando desarrollan acciones tendientes a indagar sobre el conocimiento que soporta su quehacer docente. La misma la desarrollamos como requisito para optar por el tÃtulo de Magister en Docencia de la Matemática de la MaestrÃa en Docencia de la Matemática de la Universidad Pedagógica Nacional. Adicionalmente, estuvo vinculada a una propuesta de formación liderada por el grupo de investigación Aprendizaje y Enseñanza de la GeometrÃa que busca que los profesores-estudiantes indaguen, describan y transformen su conocimiento acerca del diseño de tareas de argumentación apoyadas con Entornos de GeometrÃa Dinámica.Magister en Docencia de la MatemáticaMaestrÃaIn this document we present the report of an investigation whose purpose is to characterize the transformation of the didactic - mathematical knowledge of the two authors of this thesis, regarding the design of argumentation tasks, when they develop actions tending to inquire about the knowledge that supports their teaching work. We developed it as a requirement to opt for the Master's degree in Mathematics Teaching of the Master's Degree in Mathematics Teaching of the Universidad Pedagógica Nacional. Additionally, it was linked to a training proposal led by the Learning and Teaching of Geometry research group that seeks for teacher-students to investigate, describe and transform their knowledge about the design of argumentation tasks supported with Geometry Environments. Dynamics
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