1,518 research outputs found

    Inclusión de un índice de estimación de incertidumbre, distribución y cohesión de datos en el modelamiento borroso

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    Este trabajo presenta una propuesta de estimación de la incertidumbre y la calidad de agrupamiento producidos en la identificación de modelos mediante Sistemas de Inferencia Bor r osa del tipo Takagi-Sugeno (SIB TS). Además, propone la integración de tales medidas como criterios evaluador es del modelo con base en la incertidumbre y la partición borrosa generados durante su obtención. Tal estimación hará que el modelo obtenido sea el de menor incremento en la incertidumbre frente a los datos originales del proceso. Además, permite evaluar la distribución y densidad de los datos en los conjuntos bor r osos obtenidos durante el modelamiento usando SIB TS. Los valor es de tal índice pueden ser usados como complemento al modelo final cuando este es usado en cualquier tarea basada en modelo (diseño, optimización, control, etc.). Esas tareas suponen un modelo con incertidumbre uniforme del modelo (que se asume baja), en todo el espacio del modelo. Usando el índice pr opuesto, se puede calcular un valor más realista de la incertidumbre del modelo en cualquier punto del espacio del modelo

    Removal of the hormones 17β-estradiol and 17α-ethinylestradiol from aqueous solutions employing a decomposed peat as adsorbent material

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    REMOVAL OF THE HORMONES 17b-ESTRADIOL AND 17a-ETHINYLESTRADIOL FROM AQUEOUS SOLUTIONS EMPLOYING A DECOMPOSED PEAT AS ADSORBENT MATERIAL. This paper describes the adsorption of 17b-estradiol (E2) and 17a-ethinylestradiol (EE2) from aqueous solution by decomposed peat. The peat presented a good adsorption process, close to 76.2% for E2 removal and approximately 55.0% for EE2. Moreover, the results indicated a probable multi-layered process. Adsorption isotherms were well fitted by Freundlich model. The data were evaluated considering the pseudo-first-order and pseudo-second-order approaches, being the second more significant mechanism in the rate-controlling step. Thermodynamic data revealed that hormones adsorption onto peat is spontaneous under the employed experimental conditions. The results confirmed the potential of this adsorbent to be employed for effluents treatment

    Diagnosis of solid waste management in the petrochemical-plastic sector of Cartagena de indias, Northern Colombia

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    In the production of most petrochemical products there is a generation of associated solid waste. The objective is to diagnose solid waste management in a company in the petrochemical-plastic sector. The methodology initially consisted in the identification of the different operational areas and type of waste under the NTC GTC 24, in the second instance the solid waste classification was carried out taking into account the simple method of analysis of CEPIS and finally the quantification of The waste taking as a reference what Ruiz (2012)[1] did. It is evident that there is an increase (10.2%) in the generation of solid waste generated, from 545,750 kg in 2013 to 601,492 kg in 2014. The activities with the largest generation of solid waste (cardboard, plastic, wood) Are those of the reception and storage processes and the packaging process in each of the plants

    Evaluation of Physical Interaction during Walker-Assisted Gait with the AGoRA Walker: Strategies Based on Virtual Mechanical Stiffness

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    Smart walkers are commonly used as potential gait assistance devices, to provide physical and cognitive assistance within rehabilitation and clinical scenarios. To understand such rehabilitation processes, several biomechanical studies have been conducted to assess human gait with passive and active walkers. Several sessions were conducted with 11 healthy volunteers to assess three interaction strategies based on passive, low and high mechanical stiffness values on the AGoRA Smart Walker. The trials were carried out in a motion analysis laboratory. Kinematic data were also collected from the smart walker sensory interface. The interaction force between users and the device was recorded. The force required under passive and low stiffness modes was 56.66% and 67.48% smaller than the high stiffness mode, respectively. An increase of 17.03% for the hip range of motion, as well as the highest trunk’s inclination, were obtained under the resistive mode, suggesting a compensating motion to exert a higher impulse force on the device. Kinematic and physical interaction data suggested that the high stiffness mode significantly affected the users’ gait pattern. Results suggested that users compensated their kinematics, tilting their trunk and lower limbs to exert higher impulse forces on the device

    Towards a global understanding of vegetation-climate dynamics at multiple timescales

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    Funding Information: Acknowledgements. This paper has been realized within the Earth System Data Lab project funded by the European Space Agency. The authors acknowledge Lina Fürst for initiation of the preliminary study laying the foundation for this project. The authors acknowledge support from Ulrich Weber for data management and preprocessing. Lina M. Estupinan-Suarez acknowledges the support of the DAAD and its Graduate School Scholarship Programme (57395813). Nora Linscheid acknowledges the support of the TUM Graduate School. Lina M. Estupinan-Suarez and Nora Linscheid acknowledge the continuous support of the International Max Planck Research School for Global Biogeochemical Cycles. Felix Cre-mer acknowledges the support of the German Research Foundation project HyperSense (grant no. TH 1435/4-1). Publisher Copyright: © Author(s) 2020. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Climate variables carry signatures of variability at multiple timescales. How these modes of variability are reflected in the state of the terrestrial biosphere is still not quantified or discussed at the global scale. Here, we set out to gain a global understanding of the relevance of different modes of variability in vegetation greenness and its covariability with climate. We used > 30 years of remote sensing records of the normalized difference vegetation index (NDVI) to characterize biosphere variability across timescales from submonthly oscillations to decadal trends using discrete Fourier decomposition. Climate data of air temperature (Tair) and precipitation (Prec) were used to characterize atmosphere-biosphere covariability at each timescale. Our results show that short-term (intra-annual) and longerterm (interannual and longer) modes of variability make regionally highly important contributions to NDVI variability: short-term oscillations focus in the tropics where they shape 27% of NDVI variability. Longer-term oscillations shape 9% of NDVI variability, dominantly in semiarid shrublands. Assessing dominant timescales of vegetation-climate covariation, a natural surface classification emerges which captures patterns not represented by conventional classifications, especially in the tropics. Finally, we find that correlations between variables can differ and even invert signs across timescales. For southern Africa for example, correlation between NDVI and Tair is positive for the seasonal signal but negative for short-term and longer-term oscillations, indicating that both short- and long-term temperature anomalies can induce stress on vegetation dynamics. Such contrasting correlations between timescales exist for 15% of vegetated areas for NDVI with Tair and 27% with Prec, indicating global relevance of scale-specific climate sensitivities. Our analysis provides a detailed picture of vegetation-climate covariability globally, characterizing ecosystems by their intrinsic modes of temporal variability. We find that (i) correlations of NDVI with climate can differ between scales, (ii) nondominant subsignals in climate variables may dominate the biospheric response, and (iii) possible links may exist between short-term and longer-term scales. These heterogeneous ecosystem responses on different timescales may depend on climate zone and vegetation type, and they are to date not well understood and do not always correspond to transitions in dominant vegetation types. These scale dependencies can be a benchmark for vegetation model evaluation and for comparing remote sensing products.publishersversionpublishe

    Production of scaffolds using chitosan extracted from crustaceans

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    El quitosano está presente en el caparazón de los crustáceos, y desde hace algún tiempo ha sido utilizado en el campo de la medicina y la ingeniería de tejidos para la fabricación de matrices de crecimiento celular. En este estudio se extrajo quitosano de caparazón de crustáceos y se propuso un método sencillo para fabricar matrices con microestructura controlada. Las matrices fueron preparadas por congelación y liofilización de soluciones de quitosano y luego fueron caracterizadas por microscopía electrónica de barrido. La difracción de rayos X del quitosano extraído mostró un espectro acorde con una fuente comercial del material, evidenciando la efectividad del protocolo de extracción. La microscopía mostró poros ovalados y circulares distribuidos en todo el volumen de las muestras, con diámetros de poros entre 100 μm y 150 μm. Lo anterior demuestra que el método de producción propuesto proporciona un punto de partida para la fabricación de matrices de crecimiento celular.Chitosan is present in crustacean shells and it has been used in the fields of medicine and tissue engineering for the construction of scaffolds that support cell growth. In this study, chitosan was extracted from crustacean shells and processed into scaffolds with controlled microstructure using a simple processing method presented herein. The scaffolds were prepared by freezing and lyophilization of chitosan solutions and were characterized by scanning electron microscopy. The results showed a chitosan with an X-ray diffraction spectrum similar to that of a commercial chitosan, thus demonstrating the effectiveness of the extraction protocol. Microscopy showed oval and circular pores distributed on the bulk sample, with pore diameters between 100 μm and 150 μm. This shows that the proposed fabrication method provides a starting point for the construction of porous scaffolds that may support cell growth

    Domain Wall Junction in N=2 Supersymmetric QED in four dimensions

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    An exact solution of domain wall junction is obtained in N=2 supersymmetric (SUSY) QED with three massive hypermultiplets. The junction preserves two out of eight SUSY. Both a (magnetic) Fayet-Iliopoulos (FI) term and complex masses for hypermultiplets are needed to obtain the junction solution. There are zero modes corresponding to spontaneously broken translation, SUSY, and U(1). All broken and unbroken SUSY charges are explicitly worked out in the Wess-Zumino gauge in N=1 superfields as well as in components. The relation to models in five dimensions is also clarified.Comment: 27 pages, 6 figures, comments on zero modes added, a few references adde

    Reconstructing Neutrino Properties from Collider Experiments in a Higgs Triplet Neutrino Mass Model

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    We extend the minimal supersymmetric standard model with bilinear R-parity violation to include a pair of Higgs triplet superfields. The neutral components of the Higgs triplets develop small vacuum expectation values (VEVs) quadratic in the bilinear R-parity breaking parameters. In this scheme the atmospheric neutrino mass scale arises from bilinear R-parity breaking while for reasonable values of parameters the solar neutrino mass scale is generated from the small Higgs triplet VEVs. We calculate neutrino masses and mixing angles in this model and show how the model can be tested at future colliders. The branching ratios of the doubly charged triplet decays are related to the solar neutrino angle via a simple formula.Comment: 19 pages, 4 figures; one formula corrected, two author's names corrected; some explanatory comments adde
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