Joint modeling of lithosphere and mantle dynamics: Evaluation of constraints from global tomography models

With the advances in technology, seismological theory, and data acquisition, a number of high-resolution seismic tomography models have been published. However, discrepancies between tomography models often arise from different theoretical treatments of seismic wave propagation, different inversion strategies, and different data sets. Using a fixed velocity-to-density scaling and a fixed radial viscosity profile, we compute global mantle flow models associated with the different tomography models and test the impact of these for explaining surface geophysical observations (geoid, dynamic topography, stress, and strain rates). We use the joint modeling of lithosphere and mantle dynamics approach of Ghosh and Holt (2012) to compute the full lithosphere stresses, except that we use HC for the mantle circulation model, which accounts for the primary flow-coupling features associated with density-driven mantle flow. Our results show that the seismic tomography models of S40RTS and SAW642AN provide a better match with surface observables on a global scale than other models tested. Both of these tomography models have important similarities, including upwellings located in Pacific, Eastern Africa, Iceland, and mid-ocean ridges in the Atlantic and Indian Ocean and downwelling flows mainly located beneath the Andes, the Middle East, and central and Southeast Asia.

Simulated long-term climate response to idealized solar geoengineering

Solar geoengineering has been proposed as a potential means to counteract anthropogenic climate change, yet it is unknown how such climate intervention might affect the Earth's climate on the millennial time scale. Here we use the HadCM3L model to conduct a 1000year sunshade geoengineering simulation in which solar irradiance is uniformly reduced by 4% to approximately offset global mean warming from an abrupt quadrupling of atmospheric CO2. During the 1000year period, modeled global climate, including temperature, hydrological cycle, and ocean circulation of the high-CO2 simulation departs substantially from that of the control preindustrial simulation, whereas the climate of the geoengineering simulation remains much closer to that of the preindustrial state with little drift. The results of our study do not support the hypothesis that nonlinearities in the climate system would cause substantial drift in the climate system if solar geoengineering was to be deployed on the timescale of a millennium.

Large Eddy Simulation of Complex Turbulent Flows: Physical Aspects and Research Trends

In the current paper, we have primarily addressed one powerful simulation tool developed during the last decades-Large Eddy Simulation (LES), which is most suitable for unsteady three-dimensional complex turbulent flows in industry and natural environment. The main point in LES is that the large-scale motion is resolved while the small-scale motion is modeled or, in geophysical terminology, parameterized. With a view to devising a subgrid-scale(SGS) model of high quality, we have highlighted analyzing physical aspects in scale interaction and-energy transfer such as dissipation, backscatter, local and non-local interaction, anisotropy and resolution requirement. They are the factors responsible for where the advantages and disadvantages in existing SGS models come from. A case study on LES of turbulence in vegetative canopy is presented to illustrate that LES model is more based on physical arguments. Then, varieties of challenging complex turbulent flows in both industry and geophysical fields in the near future-are presented. In conclusion; we may say with confidence that new century shall see the flourish in the research of turbulence with the aid of LES combined with other approaches.

Proto-alphabetic inscriptions from the Wadi Arabah

Abstract: Three early West Semitic inscriptions from the Arabah valley are studied here, all of them apparently connected with the Egyptian copper-mining activity in the region, notably at Timna, in the period of the Ramessides. The most striking detail in these texts is a sign corresponding to an Egyptian hieroglyph (N6B ) which depicts two serpents guarding the sun-disc, and another with one serpent (N6 , ); these never appear on conventional tables of early alphabetic letters; this leads to a critical reappraisal of current identifications of the original picture-signs, and elaboration of a new system of interpreting early Canaanite inscriptions, involving recognition that the signs could sometimes stand for whole words and could also be used as rebuses.

Rendimiento y calidad de las interacciones sociocognitivas en díadas que trabajan colaborativamente en forma presencial y por chat

Resumen: En este trabajo se examina el rendimiento de estudiantes universitarios en razonamiento formal con y sin interacción social. La muestra N = 83 estuvo conformada por alumnos provenientes de dos universidades (UNMDP y UAA) quienes fueron asignados a dos condiciones: experimental con interacción (n = 40) y grupo control sin interacción (n = 43). El reactivo empleado consistió en una serie de pruebas del Test de Matrices Progresivas escala general y avanzada. Todos los participantes debieron resolver dichas tareas durante varias semanas: primero en forma individual (pretest), luego en forma colectiva presencial y por chat (díadas, condición experimental) y en forma individual (grupo control), y finalmente en forma individual (postest). Se registraron las interacciones que llevaron a cabo los participantes mediante videofilmación y logs del Chat. El rendimiento fue evaluado según la condición asignada: individual o grupal y en los últimos mediante una evaluación interjueces se estableció la calidad de las interacciones. Los resultados corroboran la superioridad de las díadas por sobre la performance individual; la reiteración en la fase de postest de aquellos ítems incorrectamente resueltos en el pretest más el agregado de nuevos ejercicios pusieron de relieve dos zonas de avance o de internalización de los progresos. En cuanto a la calidad de las interacciones, las mismas son coincidentes. Estos resultados abren nuevos interrogantes acerca del conflicto sociocognitivo y su papel para el avance grupal – individual.

Redes neuronales artificiales aplicadas al análisis de datos en ingeniería ambiental e impacto ambiental

Resumen: Se realiza una revisión sobre los antecedentes de las Redes Neuronales Artificiales (RNA) como método de análisis de bases de datos medioambientales, aplicado en las diversas áreas de la Ingeniería Ambiental en general y de Impacto Ambiental en particular. Se describe como ejemplo, la aplicación de RNA en los algoritmos de inversión de datos obtenidos por sensado remoto satelital, para la medición de variables geofísicas

Herramientas y métodos para la caracterización de la sostenibilidad socio, productivo, ambiental en áreas representativas de la cuenca del río Carcarañá, en el sur de la provincia de Santa Fe

Resumen: El presente trabajo aborda la caracterización socio-ambiental de un tramo de la cuenca del Río Carcarañá que atraviesa el sur de la Provincia de Santa Fe, en Argentina. El sector de interés ha sido especialmente afectado por el desarrollo de la agricultura extensiva que, si bien ha sido un elemento determinante del crecimiento económico y de la expansión tanto de las áreas de uso agropecuario, como del medio urbano y recreacional hacia el rural, ha sido sometido a un uso extensivo que requiere analizar la vulnerabilidad ambiental de la cuenca por pérdida de bienes y servicios ecosistémicos, evaluar el soporte ambiental, el uso de los recursos y la sostenibilidad ambiental. Para lograr este objetivo se propone el empleo de La metodologia multimodal, para generar un marco de evaluaciones tanto sociales como biofísicas y energéticas y además bosquejar modelos empíricos y/o teóricos que permitan interpretar la dinámica de los diferentes contaminantes en la cuenca, así como las preocupaciones de la población con relación a estos temas.

Rossby Waves With Linear Topography In Barotropic Fluids

Rossby waves are the most important waves in the atmosphere and ocean, and are parts of a large-scale system in fluid. The theory and observation show that, they satisfy quasi-geostrophic and quasi-static equilibrium approximations. In this paper, solitary Rossby waves induced by linear topography in barotropic fluids with a shear flow are studied. In order to simplify the problem, the topography is taken as a linear function of latitude variable y, then employing a weakly nonlinear method and a perturbation method, a KdV (Korteweg-de Vries) equation describing evolution of the amplitude of solitary Rossby waves induced by linear topography is derived. The results show that the variation of linear topography can induce the solitary Rossby waves in barotropic fluids with a shear flow, and extend the classical geophysical theory of fluid dynamics.

Limiting States Of Internal Wave Rays

Existing models of baroclinic tides are based upon the "traditional approximation'', i. e., neglect of the horizontal component of the Earth's rotation, leading to a well- known conclusion that no freely propagating internal waves can exist beyond the critical latitude and the wave rays are symmetric to the vertical. However, recent studies have contended that the situation may change if both the vertical and horizontal components of the Earth's rotation are taken into account. With the full account of the Coriolis force, characteristics of the internal wavefield generated by tidal flow over uneven topography are investigated. It is found that "nontraditional effects'' profoundly change not only the dynamics of internal waves but also the rate at which the barotropic tidal energy is fed into the internal wavefield. Discarding the traditional approximation, internal waves are proved to be able to generate poleward of the critical latitude, rays of which are no longer symmetric and the limiting values of ray angles become greater or less than 90 degrees, depending on the local latitude and the direction of ray. More importantly, in contrast to the predictions of models based upon the traditional approximation, a substantial conversion occurs in the situations when stratification is so weak that the buoyancy frequency is below the tidal one.

Del Noce y el tomismo

Resumen: Augusto Del Noce es un reconocido intérprete filosófico del siglo XX. Sin embargo, su método de filosofar a través de la historia y su diálogo con distintas corrientes del pensamiento han dificultado la tarea de los estudiosos a la hora de ubicar su filosofía. El estudio que aquí ofrecemos acerca de la relación del pensamiento de Del Noce con el tomismo es un aporte para comprender mejor cuáles son los supuestos metafísicos de este autor, cuál es el fundamento último de su propuesta de interpretación de la historia y de la modernidad en general. Frente a quienes entienden que Del Noce no toma suficiente distancia respecto del pensamiento idealista e inmanentista, y frente a quienes cuestionan la solidez de sus fundamentos metafísicos, sostenemos aquí que se trata de un autor que adhiere profunda y coherentemente a la metafísica del ser, y lo hace con referencias explícitas al tomismo. Para llegar a esta conclusión reconstruiremos su período de formación, su relación filosófica con el tomista Gilson y su idea de filosofía cristiana.

Shallow Water Model On Cubed-Sphere By Multi-Moment Finite Volume Method

A global numerical model for shallow water flows on the cubed-sphere grid is proposed in this paper. The model is constructed by using the constrained interpolation profile/multi-moment finite volume method (CIP/MM FVM). Two kinds of moments, i.e. the point value (PV) and the volume-integrated average (VIA) are defined and independently updated in the present model by different numerical formulations. The Lax-Friedrichs upwind splitting is used to update the PV moment in terms of a derivative Riemann problem, and a finite volume formulation derived by integrating the governing equations over each mesh element is used to predict the VIA moment. The cubed-sphere grid is applied to get around the polar singularity and to obtain uniform grid spacing for a spherical geometry. Highly localized reconstruction in CIP/MM FVM is well suited for the cubed-sphere grid, especially in dealing with the discontinuity in the coordinates between different patches. The mass conservation is completely achieved over the whole globe. The numerical model has been verified by Williamson's standard test set for shallow water equation model on sphere. The results reveal that the present model is competitive to most existing ones. (C) 2008 Elsevier Inc. All rights reserved.

En torno a la traducción en la España Medieval: el caso de la Divina Commedia

Integran este número de la revista ponencias presentadas en Studia Hispanica Medievalia VIII: Actas de las IX Jornadas Internacionales de Literatura Española Medieval, 2008, y de Homenaje al Quinto Centenario de Amadis de Gaula.

Statistical analysis of synthetic earthquake catalogs generated by models with various levels of fault zone disorder

The stress release model, a stochastic version of the elastic rebound theory, is applied to the large events from four synthetic earthquake catalogs generated by models with various levels of disorder in distribution of fault zone strength (Ben-Zion, 1996) They include models with uniform properties (U), a Parkfield-type asperity (A), fractal brittle properties (F), and multi-size-scale heterogeneities (M). The results show that the degree of regularity or predictability in the assumed fault properties, based on both the Akaike information criterion and simulations, follows the order U, F, A, and M, which is in good agreement with that obtained by pattern recognition techniques applied to the full set of synthetic data. Data simulated from the best fitting stress release models reproduce, both visually and in distributional terms, the main features of the original catalogs. The differences in character and the quality of prediction between the four cases are shown to be dependent on two main aspects: the parameter controlling the sensitivity to departures from the mean stress level and the frequency-magnitude distribution, which differs substantially between the four cases. In particular, it is shown that the predictability of the data is strongly affected by the form of frequency-magnitude distribution, being greatly reduced if a pure Gutenburg-Richter form is assumed to hold out to high magnitudes.

Razón y mística

Resumen: En este artículo intento relacionar la mística con la razón, mostrando que hay una razón de la mística. Es un logos analógico, un ana-logos, ya que la analogía es el recurso que han usado los místicos para conocer y expresar el misterio. Ya que se requiere una comprensión y una explicación, se usa la hermenéutica, para interpretar la experiencia mística y el lenguaje de los místicos. Pero tiene que ser una hermenéutica analógica, para que sea acorde con el instrumento conceptualizador que utilizan: la metáfora, la parábola y demás recursos cognoscitivos y expresivos que brinda la rica noción de analogía.

High-speed streams from coronal holes and the accelerating mechanism of the solar-wind

In this paper, the general Mach number equation is derived, and the influence of typical energy forms in the solar wind is analysed in detail. It shows that the accelerating process of the solar wind is influenced critically by the form of heating in the corona, and that the transonic mechanism is mainly the result of the adjustment of the variation of the crosssection of flowing tubes and the heat source term.The accelerating mechanism for both the high-speed stream from the coronal hole and the normal solar wind is similar. But, the temperature is low in the lower level of the coronal hole and more heat energy supply in the outside is required, hence the high speed of the solar wind; while the case with the ordinary coronal region is just the opposite, and the velocity of the solar wind is therefore lower. The accelerating process for various typical parameters is calculated, and it is found that the high-speed stream may reach 800 km/sec.