스페인의 외국인 근로자 정책

Nieves Ortega-Perez 한국노동연구원 2007 국제노동브리프 Vol.5 No.8

Nonlinear bending vibration of a prestressed thick plate

Francisco J. Nieves,Ana Bayón,Francisco Gascón,Rafael Medina,Félix Salazar 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

In this paper, the flexural vibration frequency in the antisymmetric mode of a thick plate as a function of the amplitude of the vibration and the axial force applied is investigated. With this aim, the theory of geometrically nonlinear deformation of second order and an optimized three-dimensional Ritz method are used. The plate is homogeneous, elastically linear, free from any constraints, and subjected to axial forces uniformly distributed on two of its opposite sides. Several approaches are discussed. First, the problem based on finite stress and infinitesimal strains is solved. Second, the deformation energy is assumed as the energy in the initial state plus the vibration energy of small or large amplitude. Third, without assumptions about the size of the deformation and of the vibration amplitude, the theory of nonlinear deformation is employed. Finally, numerical calculations for free vibration are compared with experimental results, including their systematic uncertainties.

Salient and Relevant Colors in Digital Images of Paintings

Juan Luis Nieves,Luis Gomez-Robledo,Javier Romero 한국색채학회 2017 AIC 2017 Jeju Vol.2017 No.10

The painters in their works not only try to faithfully shape a scene, but to submit this representation to the painter`s mind, according to his training and aesthetic taste. We find of great interest to characterize what we can understand as relevant information in a painting. Techniques for determining "salient" information in an image have recently been developed. It is a question of determining in an image the objects or areas in which an observer focus its attention. With these techniques we can establish which the fundamental colors of a painting are. We have applied the Graph-Based Visual Saliency algorithm (GBVS) to a set of digital images of six painters (Titian, El Greco, Rubens, Velázquez, Rembrandt and Vermeer). We have obtained the number of salient colors in each image after applying a method for counting discernible colors. We have taken a step further by applying thresholds at different levels to determine which the really relevant colors in a scene are, so that we approach the subjective judgments that would give an observer of the colors that stand out in a certain painting. When we evaluate the percentage of reduction of the number of discernible colors in the salient areas, this parameter is less for Rembrandt, Velázquez and Vermeer than for Titian, El Greco and Rubens. This can show a difference in the use of colors with the period that is with the evolution from the renaissance to baroque style. However, when we have evaluated the relevant colors, there is a slight variation in the average values obtained, 15 to 20. We could conclude that the number of relevant colors in the paintings do not change so significantly as the total number of discernible colors according to authors and according to paintings.

Proton conducting sulfonated polysulfone and polyphenylsulfone multiblock copolymers with improved performances for fuel cell applications

Sydonne Swaby,Nieves Ureña,María Teresa Pérez-Prior,Carmen del Río,Alejandro Várez,Jean-Yves Sanchez,Cristina Iojoiu,Belén Levenfeld 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

A series of proton exchange membranes based on sulfonated multiblock copolymers with three polysulfone(PSU) and polyphenylsulfone (PPSU) ratios (50/50, 60/40 and 75/25) are prepared following a synthesisstrategy that aims to achieve a microphase separation. A selective sulfonation of PSU blocks wasobserved in copolymers with a high proportion of PSU. The water uptake is higher in these materials(31% and 57% for SPES 50/50 and SPES 75/25, respectively at 60 C) while the tensile strength was lower(56.0 MPa and 40.6 MPa for SPES 50/50 and SPES 75/25 in the H+ form, respectively). Ionic conductivity ofSPES 75/25 membranes measured both ex situ and in situ at 80 C is 25 and 31 mScm1, respectively. Fuelcell tests reveal that SPES 75/25 shows the highest value for the maximum power density (670 mWcm2at 70 C and 100% of RH) which is higher than that achieved for SPES 50/50 (400 mWcm2). In addition,the high current density obtained for SPES 75/25 (1000 mAcm2 at 0.6 V and 70 C) compared withSPES50/50 (600 mAcm2) and Nafion 112 (450 mAcm2 at 75 C) shows its promising properties as solidelectrolyte in polymeric fuel cells.

Power Spectra and Spectral Signatures of Natural Images Under Varying Light Illuminations

Juan Ojeda,Juan Luis Nieves,Javier Romero 한국색채학회 2017 AIC 2017 Jeju Vol.2017 No.10

Although the power spectra of natural images has been extensively analyzed and studied, the influence of daylight in modeling other second order image statistics is not fully understood and has deserved little attention. The power spectra of natural images decreases as a function of frequency and it is well known that, on a log-log scale, amplitude as function of frequency lies on a straight lines. The aim of this work was to analyze the influence of daylight changes in the power spectra and signatures derived from 600 color images, which were rendered under 108 natural illuminants with Correlated Color Temperatures (CCT) from 2,735K to 25,889K. Our results suggest that the power spectra analyzed in terms of L*, a*, and b* components shows different behaviors. It seems that luminance information do not depend on the CCT as opposed to the analysis along chromatic a* and b* image components showing differences for different daylights. The spectral slope analysis of the corresponding power law shows local minima around 5,800K in the oblique orientation and are almost constant above 12,000K for all the orientations. The spectral signatures for the color Blue-Yellow and Red-Green components also show different areas and contours across daylights, being significant for the former. A reduction of the area that encloses power spectrum greater than 60% of its maximum value are found again around a CCT of 5,500K for the chromatic channels, with higher presence of vertical and horizontal frequencies in the b* component for that CCT.

Neonatal Administration of Memantine Enhances Social Cognition in Adult Rats Subjected to Early Maternal Deprivation

Eduardo Sánchez-Mendoza,Nayadoleni Nieves,Gustavo Merchor,Ezequiel Uribe 한국뇌신경과학회 2016 Experimental Neurobiology Vol.25 No.6

Schizophrenia is considered a neurodevelopmental disorder; however, all the available treatment options are used when the disease becomes clinically significant in adolescence or early adulthood. Using a developmental rat model of schizophrenia, we examined whether neonatal treatment with memantine, an NMDA receptor modulator, can improve schizophrenic-like symptoms in adulthood. Early maternal deprivation in rats produces deficits in social interaction behaviors in adulthood. In contrast, memantine administrated in neonatal rats subjected to early maternal deprivation significantly reduces deficits in social interaction behaviors in adulthood. These results raise the possibility that pharmacological treatment with memantine at the early developmental stage helps people with a risk to develop schizophrenic-like symptoms.

Colloidal Assembly Route for Responsive Colloidosomes with Tunable Permeability

Kim, J.-W.,Fernandez-Nieves, A.,Dan, N.,Utada, A. S.,Marquez, M.,Weitz, D. A. American Chemical Society 2007 NANO LETTERS Vol.7 No.9

Machine-learning-based Mechanical Properties Prediction in Foundry Production

Igor Santos,Javier Nieves,Yoseba K. Penya,Pablo G. Bringas 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

Ultimate tensile strength(UTS) is the force a material can resist untilit breaks. The only way to examine this mechanical property is the employment of destructive in spections with the subsequent cost increment. Modelling the foundry processas an expert knowledge cloud allows properly-trained machine-learning algorithms to foresee the value of UTS. Extending previous research that presented out standing results with a Bay esian-network-based approach, we have adapted an ANN and K-nearest-neighbour algorithm for the same objective. We compare the obtained results and show that artificial neural networks are more suitable than the rest of counter parts for the prediction of UTS.

ular Consumption of Concord Grape Juice Benefits Human Immunity

Cheryl A. Rowe,Meri P. Nantz,Carmelo Nieves Jr.,Robin L. West,Susan S. Percival 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.1

γδ T cells are important immune surveillance cells residing in epithelial layers lining the intestine, lung, and reproductive tract. The main objective of this study was to test the hypothesis that consumption of dietary compounds from grapes would modify γδ T-cell function. Other factors related to immune function after grape juice consumption were also tested. A randomized, double-blind, placebo-controlled, parallel intervention was conducted: 100% grape juice made from Concord grapes or a placebo beverage was consumed by 85 individuals daily for 9 weeks. Subjects were asked not to consume other red, blue, and purple fruits during the study. Blood samples, taken at the beginning and the end, were analyzed for γδ T-cell numbers and proliferation, vitamin C, antioxidant capacity, and the ability to protect DNA from strand breaks. Those consuming the grape juice had significantly greater numbers of circulating γδ T cells and higher serum vitamin C levels compared to the placebo by two-way repeated-measure analysis of variance (P<.05). Individuals consuming the placebo had lower serum antioxidant activity, less γδ T-cell proliferation, and increased DNA strand breaks when challenged with H2O2. Analysis of the data by structural equation modeling confirmed that 61% of the variance in biological functions at 9 weeks was due to grape juice consumption. Based on conventional statistical analyses, as well as on sophisticated modeling techniques, regular consumption of purple grape juice in the absence of other red, blue, or purple fruits benefited immunity in healthy, middle-aged human subjects.

COLOR APPEARANCE MAINTENANCE WITH CHANGE IN DAYLIGHT ILLUMINANTS

Javier Romero,Javier Hernandez-Andres,Juan l. Nieves,Jose A. 한국색채학회 2000 AIC MEETING SEOUL Vol.2000 No.11