2,750 research outputs found

    Tres arquitecturas neuronales implementadas en la detección y categorización de anomalías en paneles fotovoltaicos

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    Solar panels are useful and efficient tools. They need to be kept in excellent working condition, but as time goes by, they suffer from external failures manifested in the environment. Therefore, the need for effective monitoring of such systems is highlighted. Neural models are perfect candidates to perform physical damage recognition. In this case, we compare the performance of three artificial neural networks, the multilayer perceptron, the densely connected neural network, and the ResNet-50 network in this identification problem. What is intended to be obtained from this method is the practical demonstration of the use of neural networks to solve real problems.Los paneles solares son herramientas útiles y eficientes. Necesitan mantenerse en excelente estado de funcionamiento, pero a medida que pasa el tiempo, sufren fallos por externos manifestados en el ambiente. Por lo tanto, se resalta la necesidad de hacer un seguimiento efectivo de dichos sistemas. Los modelos neuronales son candidatos perfectos para realizar el reconocimiento de los daños físicos. En este caso, se compara el desempeño de tres redes neuronales artificiales, el perceptrón multicapa, la red neuronal densamente conectada y la red ResNet-50 en este problema de identificación. Lo que se pretende obtener de este método es la demostración práctica del uso de las redes neuronales para solucionar problemas reales

    A Case-Control Study of Cognitive Function in Patients with End-Stage Renal Disease Before and After Hemodialysis in Southern Spain

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    BACKGROUND: This single-center study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on modulation of thyroid hormone levels and cognition in the recovery stage of patients with cognitive dysfunction following stroke. MATERIAL AND METHODS: Seventy post-stroke patients who had cognitive impairment were randomly assigned to either the rTMS group or the control (sham) group. Both groups were administered basic treatment, with the rTMS group receiving rTMS (1 Hz, 90% MT, 1000 pulse/20 min, once a day for 5 days, for a total of 20 times), the stimulation site was the contralateral dorsolateral prefrontal cortex (DLPFC), and the sham group receiving sham stimulation which had the same stimulation parameters and site, except that the coil plane was placed perpendicular to the surface of the scalp. Cognitive function assessment and thyroid function tests were performed before and after 4 weeks of treatment. RESULTS: Serum levels of triiodothyronine (T3), free triiodothyronine (FT3), and thyroid stimulating hormone (TSH) showed a positive correlation with Montreal Cognitive Assessment (MoCA) scale score of stroke patients in the recovery phase. The post-treatment change in the scores of MoCA and Modified Barthel Index (MBI) and scores of 3 cognitive domains (visuospatial function, memory, and attention), as well as serum T3, FT3, and TSH levels, were improved more significantly in the rTMS group, and T3 and FT3 levels significantly affected the MoCA scores within the reference range. CONCLUSIONS: Serum T3, FT3, and TSH levels of stroke patients in the recovery phase were positively correlated with MoCA score. rTMS increased T3, FT3, and TSH levels and also improved MoCA and MBI of patients in the recovery phase of stroke

    Boosting Long-Term Stability of Pure Formamidinium Perovskite Solar Cells by Ambient Air Additive Assisted Fabrication

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    Due to the high industrial interest for perovskite-based photovoltaic devices, there is an urgent need to fabricate them under ambient atmosphere, not limited to low relative humidity (RH) conditions. The formamidinium lead iodide (FAPI) perovskite α-black phase is not stable at room temperature and is challenging to stabilize in an ambient environment. In this work, we show that pure FAPI perovskite solar cells (PSCs) have a dramatic increase of device long-term stability when prepared under ambient air compared to FAPI PSCs made under nitrogen, both fabricated with N-methylpyrrolidone (NMP). The T80 parameter, the time in which the efficiency drops to 80% of the initial value, increases from 21 (in N2) to 112 days (in ambient) to 145 days if PbS quantum dots (QDs) are introduced as additives in air-prepared FAPI PSCs. Furthermore, by adding methylammonium chloride (MACl) the power conversion efficiency (PCE) reaches 19.4% and devices maintain 100% of the original performance for at least 53 days. The presence of Pb–O bonds only in the FAPI films prepared in ambient conditions blocks the propagation of α- to δ-FAPI phase conversion. Thus, these results open the way to a new strategy for the stabilization in ambient air toward perovskite solar cells commercialization.Funding for open access charge: CRUE-Universitat Jaume

    Anticipated Discrimination, Choices, and Performance: Experimental Evidence

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.This paper studies experimentally whether potential perceived discrimination affects decisions in a labor-market setting with different stereotypes. Participants are assigned to a seven-person group and randomly allocated a role as a firm or worker. In each group, there are five workers and two firms. The only information firms have about each worker is a self-selected avatar (male, female or neutral) representing a worker's gender. Each firm then decides which worker to hire. Female workers react to potential discrimination when they know the task is math-related, but not otherwise. Men choose similar avatar patterns regardless of the task. Men do perform at much higher levels in the math-related task, but there is no difference in performance in the emotion-recognition task, where there is a strong female stereotype.American University of SharjahUniversity of Exete

    Desarrollo de la Red Aerobiológica de Castilla y León (RACYL)

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    XV lnternational A.P.L.E. Symposium of Palynolog

    Reflexión y transformación pedagógica. Reconocimiento a la otredad

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    Presentamos, desde una mirada crítica, algunas reflexiones y transformaciones construidas en el proceso de relatar y compartir narrativas de experiencias pedagógicas, relativas a la otredad y algunas conductas discriminatorias observadas en la cotidianidad universitaria, así como, posibles vías de transformación en las relaciones pedagógicas con los estudiantes. Analizamos diversos cuestionamientos de un grupo de profesores universitarios, tomados como referencia de análisis, para comprender la dialéctica en las escuelas o universidades, como escenarios que limitan y empoderan. Por un lado, describimos las reflexiones sobre las experiencias relatadas, en relación a prácticas o ideologías dominantes, en las que se producen y reproducen procesos estigmatizadores que desencadenan prejuicios y conductas discriminatorias en contra de ciertos estudiantes, y de igual forma narrativas de experiencias de profesores universitarios que intentan contrarrestar las narrativas dominantes, modificando discursos y prácticas, entre otros, al promover el reconocimiento a la diferencia y el respeto de la otredad, en todas sus acepciones. Finalmente presentamos algunos aprendizajes y transformaciones tanto personales como profesionales producto de las experiencias relatadas

    Diversity and abundance of rotifers during an annual cycle in the reservoir Valerio Trujano (Tepecoacuilco, Guerrero, Mexico)

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    We analyzed the diversity and density of monogonont rotifers collected from 10 sites, 5 in the littoral zone and 5 in the pelagic zone, during a 1-year period from March 2010 to April 2011 in the reservoir Valerio Trujano, altitude 820 m a.s.l. (Tepecoacuilco de Trujano, State of Guerrero, Mexico). We also measured physicochemical variables such as temperature, pH, hardness, nitrates, and phosphates. The rotifers were identified to species level and quantified using a Sedgwick-Rafter chamber. We found 62 species belonging to 28 genera and 19 families, representing 22% of total species reported for Mexico. The most abundant species were Brachionus caudatus, B. falcatus, Horaëlla thomassoni, Filinia longiseta, Conochilus dossuarius, and Keratella cochlearis. The highest rotifer densities were those of B. caudatus (around 300 ind. L-1) in June and July. The common phytoplankton genera were Pediastrum, Cosmarium, Closterium, Nitzschia, Suriella, Microcystis, Oscillatoria, and Merismopedia. The species diversity of Rotifera in the reservoir ranged from 1.3 to 3.2 in both the littoral and the pelagic regions. The saprobic index varied from 1.2 to 2 in the pelagic and 1.4 to 2.1 in the littoral region of the reservoir. Nutrient levels and indicator species (Brachionus and Trichocerca) showed that the reservoir, which was nitrogen rather than phosphorus limited, is eutrophic and moderately polluted by organic matter

    Surface-Parallel Sensor Orientation for Assessing Energy Balance Components on Mountain Slopes

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    The consistency of eddy-covariance measurements is often evaluated in terms of the degree of energy balance closure. Even over sloping terrain, instrumentation for measuring energy balance components is commonly installed horizontally, i.e. perpendicular to the geo-potential gradient. Subsequently, turbulent fluxes of sensible and latent heat are rotated perpendicular to the mean streamlines using tilt-correction algorithms. However, net radiation (Rn) and soil heat fluxes (G) are treated differently, and typically only Rn is corrected to account for slope. With an applied case study, we show and argue several advantages of installing sensors surface-parallel to measure surface-normal Rn and G. For a 17 % south-west-facing slope, our results show that horizontal installation results in hysteresis in the energy balance closure and errors of up to 25 %. Finally, we propose an approximation to estimate the surface-normal Rn, when only vertical Rn measurements are available.Andalusia Regional Government through projects P12RNM-2409Andalusia Regional Government through projects P10-RNM-6299Spanish Ministry of Economy and Competitiveness though projects CGL2010-18782, CGL2014-52838-C2-1-R (GEISpain) and CGL2013-45410-REuropean Community’s Seventh Framework Programme through INFRA-2010-1.1.16-262254 (ACTRIS),INFRA-2011-1-284274 (InGOS) and PEOPLE-2013-IOF-625988 (DIESEL) project

    Increasing the Performance and Stability of Red-Light-Emitting Diodes Using Guanidinium Mixed-Cation Perovskite Nanocrystals

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    Halide perovskite nanocrystals (PNCs) exhibit growing attention in optoelectronics due to their fascinating color purity and improved intrinsic properties. However, structural defects emerging in PNCs progressively hinder the radiative recombination and carrier transfer dynamics, limiting the performance of light-emitting devices. In this work, we explored the introduction of guanidinium (GA+) during the synthesis of high-quality Cs1–xGAxPbI3 PNCs as a promising approach for the fabrication of efficient bright-red light-emitting diodes (R-LEDs). The substitution of Cs by 10 mol % GA allows the preparation of mixed-cation PNCs with PLQY up to 100% and long-term stability for 180 days, stored under air atmosphere and refrigerated condition (4 °C). Here, GA+ cations fill/replace Cs+ positions into the PNCs, compensating intrinsic defect sites and suppressing the nonradiative recombination pathway. LEDs fabricated with this optimum material show an external quantum efficiency (EQE) near to 19%, at an operational voltage of 5 V (50–100 cd/m2) and an operational half-time (t50) increased 67% respect CsPbI3 R-LEDs. Our findings show the possibility to compensate the deficiency through A-site cation addition during the material synthesis, obtaining less defective PNCs for efficient and stable optoelectronic devices
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