535 research outputs found

    Earthquake hazard characterization by using entropy: application to northern Chilean earthquakes

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    The mechanical description of the seismic cycle has an energetic analogy in terms of statistical physics and the second law of thermodynamics. In this context, an earthquake can be considered a phase transition, where continuous reorganization of stresses and forces reflects an evolution from equilibrium to non-equilibrium states, and we can use this analogy to characterize the earthquake hazard of a region. In this study, we used 8 years (2007–2014) of high-quality Integrated Plate Boundary Observatory Chile (IPOC) seismic data for &gt; 100 000 earthquakes in northern Chile to test the theory that Shannon entropy, H, is an indicator of the equilibrium state of a seismically active region. We confirmed increasing H reflects the irreversible transition of a system and is linked to the occurrence of large earthquakes. Using variation in H, we could detect major earthquakes and their foreshocks and aftershocks, including the 2007 Mw 7.8 Tocopilla earthquake, the 2014 Mw 8.1 Iquique earthquake, and the 2010 and 2011 Calama earthquakes (Mw 6.6 and 6.8, respectively). Moreover, we identified possible periodic seismic behaviour between 80 and 160 km depth.</p

    Patterns of diversification in the high Andean Ponderacris grasshoppers (Orthoptera: Acrididae: Melanoplinae)

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    Fil: Pocco, Martina E.. División Entomología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Posadas, Paula. Laboratorio de Sistemática y Biología Evolutiva (LASBE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Lange, Carlos Ernesto. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Cigliano, María Marta. División Entomología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

    Patch Antenna Based on Metamaterials for a RFID Transponder

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    In this paper a self-diplexed antenna is proposed for a RFID transponder application. The development cycle is divided into two stages: antenna design and filters design. The antenna is based on a square microstrip patch filled with metamaterial structures. The inclusion of these structures allows simultaneous operation over several frequencies, which can be arbitrarily chosen. The antenna working frequencies are chosen to be 2.45 GHz (receiver) and 1.45 GHz (transmitter). In addition, the antenna is fed through two orthogonal coupled microstrip lines, what provides higher isolation between both ports. Some filters based on metamaterial particles are coupled or connected to the antenna feeding microstrip lines to avoid undesired interferences. This approach avoids using of an external filter or diplexer, providing larger size reduction and a compact self-diplexed antenna

    Advantages and disadvantages of competency education in the practical subjects of the Faculty of Veterinary Medicine and Animal Science, National Autonomous University of Mexico

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    Resúmenes IV Congreso VetDoc de Docencia Veterinaria, León 2017 (6-7 de Julio)[ES] Desde el año 2010 en la Facultad de Medicina Veterinaria y Zootecnia de la Universidad Nacional Autónoma de México (FMVZ-UNAM), se planteó la posibilidad de adecuar el plan de estudios a un modelo educativo basado en competencias, donde el propio alumno regule el aprendizaje y adquiera además de conocimientos teóricos, herramientas para solucionar problemas y formar un criterio propio, tratando de dejar de lado los modelos educativos del siglo XX, donde el docente era el único poseedor y transmisor de conocimientos

    Heart Rate Variability Analysis Guided by Respiration in Major Depressive Disorder

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    In this study a Heart Rate Variability (HRV) analysis guided by respiration to evaluate different patterns of Autonomic Nervous System (ANS) in response to a cognitive stressor between Major Depressive Disorder (MDD) and control (CT) subjects is presented. Cardiorespiratory Time Frequency Coherence (TFC) reveals the local coupling of HRV and respiration signal which is essential and usually not included in estimation of ANS measures derived by HRV. Parasympathetic activity of ANS is measured as the power at the frequencies where TFC between HRV and respiration is significant, whereas sympathetic dominance is measured as the normalized power in the low frequency band [0.04,0.15] Hz of HRV excluding the power of those frequencies related to respiration. Results showed significantly lower (p <; 0.05) sympathetic dominance in MDD with respect to CT subjects during stress, suggesting that ANS reactivity as response to stress stimuli is lower in MDD patients. The study of ANS reactivity to a stressor may serve as a biomarker useful for the early diagnosis and monitoring of MDD patients
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