6,742 research outputs found
On Attitudes Toward Spanish Varieties: A Bilingual Perspective
This study explores the attitudes of 25 English-Spanish bilingual speakers from Tucson (Arizona) towards their own variety and compares them with their attitudes toward monolingual varieties of Mexican (from Hermosillo) and Peninsular Spanish (from Murcia and Madrid). Our analysis points to a clear influence of the standard language ideology (MILROY, 2001) on shaping these attitudes, escalated by a tendency among bilinguals in diglossic societies to feel insecure about their own variety as a minority language, or towards a feeling of linguistic self-hatred.
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Este estudo explora as atitudes de 25 falantes bilíngues de espanhol e inglês de Tucson (Arizona) com relação à sua própria variedade linguística, comparando essas atitudes em relação ao espanhol de Hermosillo (México) e a duas variedades peninsulares: a espanhola de Múrcia e a de Madrid. Nossa análise mostra uma clara influência da ideologia da língua padrão (MILROY, 2001) em determinar essas atitudes, agravada pela tendência de os falantes bilíngues de sociedades diglóssicas se sentirem inseguros quanto à sua própria variedade como uma língua minoritária, ou relacionada a um sentimento de auto-ódio linguístico
Schwarz alternating domain decomposition approach for the solution of mixed heat convection flow problems based on the method of approximate particular solutions
The incompressible two-dimensional Navier-Stokes equations including thermal
energy balance equation are solved by the recently developed Method of Approximate
Particular Solutions (MAPS). In a previous authors’ work this method was implemented
to solve the two-dimensional Stokes equations by employing the pressure and velocity particular
solutions obtained by Oseen’s decomposition with the Multiquadric (MQ) RBF
as non-homogeneous term. A pressure-velocity linkage strategy is not required since the
pressure particular solutions are obtained from the velocity ones. In the present contribution,
the Navier-Stokes equations with Boussinesq approximation are solved by linearizing
the convective term in a Picard iterative scheme. With the velocity values obtained at
each of the Picard iterations, the energy conservation equation is solved by the MAPS by
approximating temperature with the particular solutions of a Poisson problem with the
MQ as a forcing term. With the aim of improving the computational efficiency of the
global strategy, the two-dimensional domain is split into overlapped rectangular subdomains
where the Schwarz Alternating Algorithm is employed to find a solution by using
velocity and temperatures values from neighbouring zones as boundary conditions. The
mixed convection lid-driven cavity flow problem is solved for moderate Reynolds and low
Richardson numbers with the aim of validating the proposed method
Two dimensional solution of the advection-diffusion equation using two collocation methods with local upwinding RBF
The two-dimensional advection-diffusion equation is solved using two local
collocation methods with Multiquadric (MQ)Radial Basis Functions (RBFs). Although
both methods use upwinding, the first one, similar to the method of Kansa, approximates
the dependent variable with a linear combination of MQs. The nodes are grouped into
two types of stencil: cross-shaped stencil to approximate the Laplacian of the variable
and circular sector shape stencil to approximate the gradient components. The circular
sector opens in opposite to the flow direction and therefore the maximum number of nodes
and the shape parameter value are selected conveniently. The second method is based
on the Hermitian interpolation where the approximation function is a linear combination
of MQs and the resulting functions of applying partial differential equation (PDE) and
boundary operators to MQs, all of them centred at different points. The performance
of these methods is analysed by solving several test problems whose analytical solutions
are known. Solutions are obtained for different Peclet numbers, Pe, and several values
of the shape parameter. For high Peclet numbers the accuracy of the second method
is affected by the ill-conditioning of the interpolation matrix while the first interpolation method requires the introduction of additional nodes in the cross stencil. For low Pe both
methods yield accurate results. Moreover, the first method is employed to solve the twodimensional
Navier-Stokes equations in velocity-vorticity formulation for the lid-driven
cavity problem moderate Pe
Theoretical design of stable small aluminium-magnesium binary clusters
We explore in detail the potential energy surfaces of the AlxMgy (x, y = 1–4) systems as case studies to test the utility and limitations of simple rules based on electron counts and the phenomenological shell model (PSM) for bimetallic clusters. We find that it is feasible to design stable structures that are members of this set of small Al–Mg binary clusters, using simple electron count rules, including the classical 4n + 2 Hückel model, and the most recently proposed PSM. The thermodynamic stability of the title compounds has been evaluated using several different descriptors, including the fragmentation energies and the electronic structure of the systems. Three stable systems emerge from the analysis: the Al4Mg, Al2Mg2 and Al4Mg4 clusters. The relative stability of Al4Mg is explained by the stability of the Al42− subunit to which the Mg atom donates its electrons. Here the Mg2+ sits above the aromatic 10 π-electron Al42− planar ring. The Al2Mg2 and Al4Mg4 clusters present more complicated 3D structures, and their stabilities are rationalized as a consequence of their closed shell nature in the PSM, with 10 and 20 itinerant electrons, respectively
Co-Inoculation of Plant-Growth-Promoting Bacteria Modulates Physiological and Biochemical Responses of Perennial Ryegrass to Water Deficit
Perennial ryegrass is a forage commonly used in temperate regions for livestock feeding; however, its yield is affected by reduced biomass production under water deficit. In a previous study, three co-inoculations of beneficial bacteria were selected based on their ability to promote plant
growth under reduced water availability. The aim of this work was to elucidate some mechanisms by which the selected bacteria can help improve the response of perennial ryegrass to water deficit. Ryegrass plants were inoculated with each of the co-inoculations (Herbaspirillum sp. AP02 Herbaspirillum sp. AP21; Herbaspirillum sp. AP02–Pseudomonas sp. N7; Herbaspirillum sp. AP21–Azospirillum brasilense
D7) and subjected to water deficit for 10 days. Physiological and biochemical measurements were taken 10 days after stress and shortly after rehydration. The results showed that bacteria had a positive effect on shoot biomass production, dissipation of excess energy, and proline and chlorophyll
pigments during the days of water deficit (p < 0.05). The leaf water status of the inoculated plants was 12% higher than that of the uninoculated control after rehydration. Two Herbaspirillum strains showed greater potential for use as biofertilizers that help ameliorate the effects of water deficit
TALISMAN+: Intelligent System for Follow-Up and Promotion of Personal Autonomy
The TALISMAN+ project, financed by the Spanish Ministry of Science and Innovation, aims to research and demonstrate innovative solutions transferable to society which offer services and products based on information and communication technologies in order to promote personal autonomy in prevention and monitoring scenarios. It will solve critical interoperability problems among systems and emerging technologies in a context where heterogeneity brings about accessibility barriers not yet overcome and demanded by the scientific, technological or social-health settings
Solución bidimensional sin malla de la ecuación no lineal de convección-difusión-reacción mediante el método de Interpolación Local Hermítica
A meshless numerical scheme is developed for solving a generic version of the non-linear convection-diffusion-reaction equation in two-dimensional domains. The Local Hermitian Interpolation (LHI) method is employed for the spatial discretization and several strategies are implemented for the solution of the resulting non-linear equation system, among them the Picard iteration, the Newton Raphson method and a truncated version of the Homotopy Analysis Method (HAM). The LHI method is a local collocation strategy in which Radial Basis Functions (RBFs) are employed to build the interpolation function. Unlike the original Kansa’s Method, the LHI is applied locally and the boundary and governing equation differential operators are used to obtain the interpolation function, giving a symmetric and non-singular collocation matrix. Analytical and Numerical Jacobian matrices are tested for the Newton-Raphson method and the derivatives of the governing equation with respect to the homotopy parameter are obtained analytically. The numerical scheme is verified by comparing the obtained results to the one-dimensional Burgers’ and two-dimensional Richards’ analytical solutions. The same results are obtained for all the non-linear solvers tested, but better convergence rates are attained with the Newton Raphson method in a double iteration scheme.Se desarrolla un esquema numérico sin malla para resolver una versión genérica de la ecuación no lineal de convección-difusión-reacción en dominios bidimensionales. El método de Interpolación Hermitiana Local (LHI) se emplea para la discretización espacial y se implementan varias estrategias para la solución del sistema de ecuaciones no lineal resultante, entre ellas la iteración Picard, el método Newton Raphson y una versión truncada del Método de Análisis de Homotopía. (JAMÓN). El método LHI es una estrategia de colocación local en la que se utilizan funciones de base radial (RBF) para construir la función de interpolación. A diferencia del método original de Kansa, el LHI se aplica localmente y los operadores diferenciales de ecuación límite y gobernante se utilizan para obtener la función de interpolación, dando una matriz de colocación simétrica y no singular. Las matrices analíticas y numéricas jacobianas se prueban para el método de Newton-Raphson y las derivadas de la ecuación de gobierno con respecto al parámetro de homotopía se obtienen analíticamente. El esquema numérico se verifica comparando los resultados obtenidos con las soluciones analíticas unidimensionales de Burgers y Richards bidimensionales. Se obtienen los mismos resultados para todos los solucionadores no lineales probados, pero se obtienen mejores tasas de convergencia con el método Newton Raphson en un esquema de doble iteración
Three-Dimensional Handheld Scanning to Quantify Head-Shape Changes in Spring-Assisted Surgery for Sagittal Craniosynostosis
Three-dimensional (3D) imaging is an important tool for diagnostics, surgical planning, and evaluation of surgical outcomes in craniofacial procedures. Gold standard for acquiring 3D imaging is computed tomography that entails ionizing radiations and, in young children, a general anaesthesia. Three-dimensional photographic imaging is an alternative method to assess patients who have undergone calvarial reconstructive surgery. The aim of this study was to assess the utility of 3D handheld scanning photography in a cohort of patients who underwent spring-assisted correction surgery for scaphocephaly. Pre- and postoperative 3D scans acquired in theater and at the 3-week follow-up in clinic were postprocessed for 9 patients. Cephalic index (CI), head circumference, volume, sagittal length, and coronal width over the head at pre-op, post-op, and follow-up were measured from the 3D scans. Cephalic index from 3D scans was compared with measurements from planar x-rays. Statistical shape modeling (SSM) was used to calculate the 3D mean anatomical head shape of the 9 patients at the pre-op, post-op, and follow-up. No significant differences were observed in the CI between 3D and x-ray. Cephalic index, volume, and coronal width increased significantly over time. Mean shapes from SSM visualized the overall and regional 3D changes due to the expansion of the springs in situ. Three-dimensional handheld scanning followed by SSM proved to be an efficacious and practical method to evaluate 3D shape outcomes after spring-assisted cranioplasty in individual patients and the population
The Esthetic Perception of Morphological Severity in Scaphocephalic Patients is Correlated With Specific Head Geometrical Features
OBJECTIVE: To investigate the relationship between perception of craniofacial deformity, geometric head features, and 3D head shape analyzed by statistical shape modeling (SSM). PATIENTS: A total of 18 unoperated patients with scaphocephaly (age = 5.2 ± 1.1m)-6 were followed-up after spring-assisted cranioplasty (SAC) (age = 9.6 ± 1.5m)-and 6 controls (age = 6.7 ± 2.5m). MAIN OUTCOME MEASURES: 3D head shapes were retrieved from 3D scans or computed tomography (CTs). Various geometrical features were measured: anterior and posterior prominence, take-off angle, average anterior and posterior lateral and horizontal curvatures, cranial index (CI) (cranial width over length), and turricephaly index (TI) (cranial height over length). SSM and principal component analysis (PCA) described shape variability. All models were 3D printed; the perception of deformity was blindly scored by 9 surgeons and 1 radiologist in terms of frontal bossing (FB), occipital bulleting (OB), biparietal narrowing (BN), low posterior vertex (LPV), and overall head shape (OHS). RESULTS: A moderate correlation was found between FB and anterior prominence (r = 0.56, P < .01) and take-off angle (r = - 0.57, P < .01). OB correlated with average posterior lateral curvature (r = 0.43, P < 0.01) similarly to BPN (r = 0.55, P < .01) and LPV (r = 0.43, P < .01). OHS showed strong correlation with CI (r = - 0.68, P < .01) and TI (r = 0.63, P< .01). SSM Mode 1 correlated with OHS (r = 0.66, p < .01) while Mode 3 correlated with FB (r = - 0.58, P < .01). CONCLUSIONS: Esthetic cranial appearance in craniofacial patients is correlated to specific geometric parameters and could be estimated using automated methods such as SSM
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