4,074 research outputs found

    Impact of surface roughness in nanogap plasmonic systems

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    Recent results have shown unprecedented control over separation distances between two metallic elements hundreds of nanometers in size, underlying the effects of free-electron nonlocal response also at mid-infrared wavelengths. Most of metallic systems however, still suffer from some degree of inhomogeneity due to fabrication-induced surface roughness. Nanoscale roughness in such systems might hinder the understanding of the role of microscopic interactions. Here we investigate the effect of surface roughness in coaxial nanoapertures resonating at mid-infrared frequencies. We show that although random roughness shifts the resonances in an unpredictable way, the impact of nonlocal effects can still be clearly observed. Roughness-induced perturbation on the peak resonance of the system shows a strong correlation with the effective gap size of the individual samples. Fluctuations due to fabrication imperfections then can be suppressed by performing measurements on structure ensembles in which averaging over a large number of samples provides a precise measure of the ideal system's optical properties

    FIC/FEM formulation with matrix stabilizing terms for incompressible flows at low and high Reynolds numbers

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s00466-006-0060-yWe present a general formulation for incompressible fluid flow analysis using the finite element method. The necessary stabilization for dealing with convective effects and the incompressibility condition are introduced via the Finite Calculus method using a matrix form of the stabilization parameters. This allows to model a wide range of fluid flow problems for low and high Reynolds numbers flows without introducing a turbulence model. Examples of application to the analysis of incompressible flows with moderate and large Reynolds numbers are presented.Peer ReviewedPostprint (author's final draft

    Social segregation of indigenous migrants in Mexico: An overview from Monterrey

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    In Mexico, rural to urban migration is a clearly noticeable phenomenon. During the last few years, there has been spontaneous growth in the migration of indigenous people towards the northern cities of Mexico, especially to Monterrey, in search of employment. Once the migrants arrive in this metropolis, they face difficulties adjusting and adapting to the city environment because of hidden discrimination. The main argument and hypothesis of this paper is that indigenous people isolate themselves and segregate themselves socially due to fear of (cultural and racial) discrimination and violence. For this study, data were obtained from fieldwork carried out during 2009 and 2010 in Monterrey, Mexico, where we interviewed 350 indigenous people that had moved there from different parts of the country

    Sustainable landscape in arid zones : useful ornamental xeric species

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    Se analiza el valor económico, ecológico y paisajístico de especies vegetales, pertenecientes a la flora espontánea de Mendoza (Argentina), resistentes a la sequía y que pueden alcanzar porte arbóreo. Su empleo ahorra agua de riego en espacios verdes ornamentales y de protección ambiental. Se sugiere medidas de conservación de las especies espontáneas más útiles paisajísticamente, así como normas generales sobre métodos de plantación y mantenimiento. Se recomiendan especies leñosas espontáneas de la provincia, de bajo requerimiento hídrico, utilizables paisajísticamente.This paper analyzes the economic, ecological and landscape value of drought resistant species from the spontaneous flora of Mendoza (Argentina). Some of such species could reach tree size and its use might save the irrigation water used for ornamental and environmental protection areas. Actions to protect the most useful spontaneous species, as well as general rules for plantation and maintenance are suggested. Spontaneous wooden species of low water requirements, to use in different landscape objectives, are recommended.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Manzano, Enrique R.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Carrieri, Sergio A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Fioretti, Sonia B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuari

    The Remarkable Be Star HD110432

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    HD110432 has gained considerable attention because it is a hard, variable X-ray source similar to gamma Cas. From time-serial echelle data obtained over two weeks during 2005 January and February, we find several remarkable characteristics in the star's optical spectrum. The line profiles show rapid variations on some nights which can be most likely be attributed to irregularly occurring and short-lived migrating subfeatures. Such features have only been observed to date in gamma Cas and AB Dor, two stars for which it is believed magnetic fields force circumstellar clouds to corotate over the stellar surface. The star's optical spectrum also exhibits a number of mainly FeII and HeI emission features with profiles typical of an optically thin disk viewed edge-on. Using spectral synthesis techniques, we find that its temperature is 9800K +/-300K, that its projected area is a remarkably large 100 stellar areas, and its emitting volume resides at a distance of 1 AU from the star. We also find that the star's absorption profiles extend to +/-1000 km/s, a fact which we cannot explain. Otherwise, HD110432 and gamma Cas share similarly peculiar X-ray and optical characteristics such as high X-ray temperature, erratic X-ray variability on timescales of a few hours, optical emission lines, and submigrating features in optical line profiles. Because of these similarities, we suggest that this star is a new member of a select class of "gamma Cas analogs."Comment: 31 pages, 9 figures, accepted by ApJ (3/20/06

    Approximation of the two-fluid flow problem for viscoelastic fluids using the level set method and pressure enriched finite element shape functions

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    The numerical simulation of complex flows has been a subject of intense research in the last years with important industrial applications in many fields. In this paper we present a finite element method to solve the two immiscible fluid flow problems using the level set method. When the interface between both fluids cuts an element, the discontinuity in the material properties leads to discontinuities in the gradients of the unknowns which cannot be captured using a standard finite element interpolation. The method presented in this work features a local enrichment for the pressure unknowns which allows one to capture pressure gradient discontinuities in fluids presenting different density values. The method is tested on two problems: the first example consists of a sloshing case that involves the interaction of a Giesekus and a Newtonian fluid. This example shows that the enriched pressure functions permit the exact resolution of the hydrostatic rest state. The second example is the classical jet buckling problem used to validate our method. To permit the use of equal interpolation between the variables, we use a variational multiscale formulation proposed recently by Castillo and Codina (2014) [21], that has shown very good stability properties, permitting also the resolution of the jet buckling flow problem in the the range of Weissenberg number 0 < We < 100, using the Oldroyd-B model without any sign of numerical instability. Additional features of the work are the inclusion of a discontinuity capturing technique for the constitutive equation and some comparisons between a monolithic resolution and a fractional step approach to solve the viscoelastic fluid flow problem from the point of view of computational requirements. (C) 2015 Elsevier B.V. All rights reserved.Postprint (author's final draft

    Environmental value calculus of the frontal urban gardens. : Mendoza (Argentina)

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    Los espacios verdes y, en general, la vegetación que cumple funciones estéticas y de protección ambiental son valorados, medidos y calculados por el área destinada al cultivo, en lugar de basar los cálculos en los elementos vegetales constitutivos. Esto significa una simplificación excesiva de la valoración de la vegetación (actual o proyectada) que no aporta criterios de cuantificación valorativa necesarios, actualmente, tanto para preservar vegetación existente como para políticas de desarrollo urbano y proyectos de ingeniería del mejoramiento ambiental. En el presente trabajo se propone aplicar a la valoración de los jardines frontales urbanos de la ciudad de Mendoza una metodología cuantitativa desarrollada por R. Codina et al., que se apoya en un concepto nuevo que es su influencia como mejoradores ambientales. La ecuación de cálculo se integra con índices de valoración como el Índice de Vegetación Ambientalmente Activa y el Índice Ambiental Urbanístico, que permiten cuantificar la importancia urbanística y ambiental de la vegetación. También se propone una base para implementar una política de incentivo de los jardines frontales mediante la disminución del avalúo valor terreno del impuesto inmobiliario, en una escala progresiva según el Índice Ambiental Urbanístico de cada propiedad, tendiente a la transformación de la ciudad en una ciudad-jardín, mejorando la calidad de vida y el atractivo turístico urbano.The green spaces and in general, the vegetation used for aesthetics and environmental protection are valuated, measured and calculated through the area destinated to the cultivation instead of calculus based in the component vegetal elements. This means an excessive simplification in the vegetal valoration (current or projected) that not contribute with cuantitative valoration criterion, which are needed today in preservation of existent vegetation, urban development policies and in engineering projects of environmental improvement. This work proposes the application to the frontal urbans gardens in Mendoza city, of a cuantitative metodology developed by R. Codina et al., which is based in a new concept, it influences as environmental improvement. The calculus equation is to be composed of valoration indexes as the Environmental Active Vegetation Index and the Urbanistic Environmental Index, that allow the cuantification of the urbanistic and environmental importance of vegetation. Also is proposed a base for the implementation of an incentive policy of the frontals urban gardens through the diminution of the real estate tax land appraisal, in a progressive scale according the Urbanistic Environmental Index of each property, tending to transformation the city in a garden-city, to improve the life´s quality and the urban touristic charm.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Passera, Carlos B.. Universidad Autónoma de Nuevo León (México). Facultad de Ciencias BiológicasFil: Naranjo, Gabriela. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Carrieri, Sergio A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Fioretti, Sonia B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Manzano, Enrique R.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuari

    Photometric Observations of Three High Mass X-Ray Binaries and a Search for Variations Induced by Orbital Motion

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    We searched for long period variation in V-band, Ic-band and RXTE X-ray light curves of the High Mass X-ray Binaries (HMXBs) LS 1698 / RX J1037.5-5647, HD 110432 / 1H 1249-637 and HD 161103 / RX J1744.7-2713 in an attempt to discover orbitally induced variation. Data were obtained primarily from the ASAS database and were supplemented by shorter term observations made with the 24- and 40-inch ANU telescopes and one of the robotic PROMPT telescopes. Fourier periodograms suggested the existence of long period variation in the V-band light curves of all three HMXBs, however folding the data at those periods did not reveal convincing periodic variation. At this point we cannot rule out the existence of long term V-band variation for these three sources and hints of longer term variation may be seen in the higher precision PROMPT data. Long term V-band observations, on the order of several years, taken at a frequency of at least once per week and with a precision of 0.01 mag, therefore still have a chance of revealing long term variation in these three HMXBs.Comment: Accepted, RAA, May, 201

    The visual resourses in the territorial arrangement : I- Potrerillos (Mendoza, Argentina)

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    Se presenta la primera etapa del relevamiento de los recursos paisajísticos de la provincia de Mendoza, con el ajuste metodológico efectuado mediante una prueba piloto desarrollada sobre la Ruta Nac. N° 7, desde el Acceso sur en Luján de Cuyo (límite este) hasta Potrerillos inclusive (límite oeste). Los límites norte y sur están abarcados por el horizonte observable desde la ruta que atraviesa el área en sentido este-oeste. Se seleccionaron los puntos representativos mediante dos tipos de muestreo: sistemático y discrecional. En base a la catalogación de los recursos visuales se diseña una zonificación referencial general con miras al ordenamiento territorial y uso del suelo en distintas actividades de desarrollo futuro: turístico, reservas, residencial, agrícola, industrial. Se valora la calidad estética del paisaje aplicando, además, índices valorativos de la vulnerabilidad de los espacios a las actividades humanas (Índice de Naturalidad e Índice de Fragilidad), para obtener valores de la Calidad Visual Vulnerable del paisaje. Estos valores se grafican en planos que representan las distintas calidades alcanzadas y se complementa con una descripción de los puntos analizados, recomendaciones para el mejoramiento paisajístico a través de introducción o conducción de vegetación y fotografías documentales de las vistas analizadas.This paper presents the first stage of the inventory of visual or landscape resources of the province of Mendoza. The metodological adjustment was done in an area of the high basin of Mendoza river, along the route n° 7, from the South Access in Luján of Cuyo, to Potrerillos, as limits east and west. The observable horizons from the route crossing the area in east-west direction, are the nort and south limits. Representative points were chosen across these limits by means of sistematic and discretional sampling. By the cataloguing of the visual resources, a general reference zonification is designed for territorial arrangement and use of land in future development and activities such as touristic, reserves, residencial, agricultural, industrial. The landscape aesthetic quality is evaluated, applying in addition, vulnerability valoration indexes of the spaces to the human activities (Naturalness index and Fragility index) to achieve Landscape Vulnerable Visual Quality values. These values are plotted in charts that represents the different achieved qualities and are complemented with a description of analized points, recomendations for the lanscape improvements through vegetable introduction and management, and documental pictures of analized views.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Manzano, Enrique R.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Day, Mario.Fil: Passera, Carlos B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Fioretti, Sonia B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Carrieri, Sergio A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Cappe, Osvaldo Emilio. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ingeniería Agrícol

    Social deprivation and exposure to health promotion. A study of the distribution of health promotion resources to schools in England

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    This article has been made available through the Brunel Open Access Publishing Fund and is available from the specified link - Copyright @ 2010 Chivu and ReidpathBACKGROUND: Area deprivation is a known determinant of health. It is also known that area deprivation is associated with lower impact health promotion. It is less well known, however, whether deprived areas are less responsive to health promotion, or whether they are less exposed. Using data from a national, school-based campaign to promote vaccination against the human papilloma virus (HPV), the relationship between area deprivation and exposure was examined. METHODS: Taking advantage of a health promotion campaign to provide information to schools about HPV vaccination, a cross sectional study was conducted to examine the relationship between area level, social deprivation, and take-up of (i.e., exposure to) available health promotion material. The sample was 4,750 schools across England, including government maintained and independent schools. The relationship between area deprivation and exposure was examined using bi- and multivariate logistic regression. RESULTS: It was found that schools in the least deprived quintile had 1.32 times the odds of requesting health promotion materials than schools in the most deprived areas (p = .01). This effect was independent of the school size, the type of school, and the geographic region. Conclusion The relationship between area deprivation and the impact of health promotion may be due, at least in part, to differential levels of exposure. The study was limited in scope, pointing to the need for more research, but also points to potentially important policy implications
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