Imaginación y reacción en los Campamentos de refugiados saharauis : construcción de la cotidianeidad e identidad frente al otro extranjero (nasrani) en el contexto de la diáspora

Los Campamentos de refugiados son una parte dramática de la historia del pueblo saharaui con poca referencia bibliográfica. Esta situación ha impuesto una serie de límites ante los cuales la imaginación de la sociedad civil ha reaccionado y ha generado un espacio alternativo donde vivir. La revolución contra el colonialismo es además una lucha por cambiar el propio pasado y algunos hábitos culturales. Y desde el refugio y el exilio se han abierto nuevas alternativas que ha aprovechado la educación como pilar fundamental de la revolución. Desde ella se prepara a las nuevas generaciones para la libertad y a través de ella se recupera y enseña la identidad nacional saharaui. Este trabajo muestra la labor y las dificultades que rodean al mundo de la educación en el refugio y la importancia que tiene la memoria histórica.Saharawi refugee camps, with little references, are part of the recent tragic history. This situation has imposed a series of limits to which the imagination of civil society has reacted and has generated an alternative space in which to live. The revolution against colonialism was also a struggle to change the past and some cultural habits. And the refuge and the exile have opened new alternatives which have taken education as a fundamental pillar of the revolution. Since it prepares future generations for freedom and through it to recover and teach the Saharawi national identity. This paper shows the work and the difficulties surrounding the world of education at the shelter and the importance of historical memory

Transforming Teenagers: Integrating Social Justice into Catholic Youth Ministry or Catholic Education

This article investigates transforming teenagers through the process on integrating and implementing social justice concepts and principles into Catholic youth ministry and Catholic secondary and higher education. The essay addresses four aspects concerning social justice and Catholic young people: (1) it briefly studies the ecclesial documents concerning social justice and young people, (2) it looks at integrating Christian social justice concepts and principles into Catholic ministry and academia, (3) it examines the benefits of social justicelearning initiatives, and (4) it discusses two types of social justice-learning initiatives that work well in Catholic youth ministry and Catholic education-- praxis-based education and immersion trips. “I believe that unarmed truth and unconditional love will have the final word in reality. That is why right temporarily defeated is stronger than evil triumphant.”i Martin Luther King, Jr. Nobel Prize for Peace Acceptance Speech December 10, 196

Estimación de Tres Índices de Concentración Económica: Una Aplicación al Sector Bancario en Nicaragua

El artículo presenta tres indicadores para estimar el grado de concentración económica del sector bancario en Nicaragua. Utilizando datos anuales del periodo 2007 al 2015 del Banco Central de Nicaragua. Los indicadores calculados son el índice de Herfindahl-Hirschman (en adelante IHH), el índice de Ojiva (en adelante OJV) y el índice de Dominancia (en adelante ID). Estos índices se calcularán para los activos, créditos y depósitos totales de la banca privada nacional, de modo que se tendrán tres valores respecto a cada índice de concentración: uno en relación con las cuentas de activos, créditos y finalmente depósitos. Se concluye que el sector bancario en Nicaragua es altamente concentrado, para cuentas de activos, depósitos y créditos. Los índices IHH, OJV e ID, presentan una trayectoria creciente a futuro en el nivel de concentración de esta industria en Nicaragua

Influence of Nb-doping on the structural and electrical properties of lanthanum molybdates, La5.4MoO11.1

Nowadays, hydrogen is receiving a great deal of attention as an energy carrier. Commonly, it is obtained by hydrocarbons reforming, such as natural gas, coal and biomass. However, the resulting hydrogen needs to be purified to remove by-products and impurities, increasing the production costs. An alternative for hydrogen production is proton-conducting ceramics, where hydrogen separation takes place via a chemical potential gradient across the membrane.1, 2 In this work, Nb-doped La6MoO12--based compounds have been investigated as part of a new family of materials very competitive as SOFC electrolyte and hydrogen separation membranes.3 These materials, La5.4Mo1-xNbxO11.1-x/2 (x = 0.05, 0.10, 0.15 y 0.20) were synthesized by the freeze-drying precursor method and calcination conditions have been optimized to obtain single phases. A complete characterization has been carried out using X-Ray powder diffraction and scanning and transmission electron microscopy. The total conductivity was determined by complex impedance spectroscopy at different atmospheres. Different polymorphs are obtained as a function of the cooling rate and the dopant amount. The samples cooled by quenching are cubic with a fluorite-type structure (Fm3 ̅m) and the ones cooled at 50 y 0.5 ºC•min-1 are rhombohedral (R1 and R2 polymorphs). For niobium contents higher than x = 0.10 the R1 polymorph is stabilised at cooling rates equal or inferior to 50 ºC•min-1. For all three series, the incorporation of niobium into La5.4MoO11.1 increases the conductivity, reaching the best values for x=0.10 and the sample obtained by quenching.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Incorporation of trajectory behaviors in the vicinities of different planetary moons using Finite-Time Lyapunov Exponent Maps

There is an increasing interest in future space missions devoted to the exploration of key moons in the Solar system. These many different missions may involve libration point orbits as well as trajectories that satisfy different endgames in the vicinities of the moons. To this end, an efficient design strategy to produce low-energy transfers between the vicinities of adjacent moons of a planetary system is introduced that leverages the dynamics in these multi-body systems. Such a design strategy is denoted as the moon-to-moon analytical transfer (MMAT) method. It consists of a general methodology for transfer design between the vicinities of the moons in any given system within the context of the circular restricted three-body problem, useful regardless of the orbital planes in which the moons reside. A simplified model enables analytical constraints to efficiently determine the feasibility of a transfer between two different moons moving in the vicinity of a common planet. Additionally, Finite-Time Lyapunov Exponent (FTLE) maps within the context of the MMAT scheme are incorporated to enable direct transfers between moons that offer a wide variety of trajectory patterns and endgames, such as temporary captures, transits, takeoffs and landings. The resulting technique is demonstrated to be applicable to several mission scenarios

Orbit and Attitude Coupling in the Full Higher-Fidelity Ephemeris Model within the context of the Geometric Mechanics Framework

Predicting the orientation of spacecraft traveling within the Cislunar (Earth-Moon) region is necessary to ensure the success of future missions planned within that realm of space. This research looks to consider the coupling between translational and rotational motion to not only improve trajectory accuracy, but to also introduce the prediction of attitude in mission planning. Trajectories computed in the circular restricted full three-body problem (CRF3BP), previously proposed by the authors, allow for the spacecraft to be modeled as a rigid-body rather than a point mass. These trajectories are utilized as initial guesses for a full ephemeris model, where the gravitational field of perturbing bodies and the eccentricity of the Moon\u27s orbit alter these trajectories within this more complex dynamical environment. It has been shown through this research that attitude can be predicted in a full ephemeris model by the CRF3BP, a novel contribution to the field of astrodynamics research

Study of Earth-Moon trajectories with solar sail propulsion

The computation of Earth-to-Moon trajectories constitutes an important and interesting chapter of spacecraft trajectory design. The traditional techniques based on Hohmann maneuvers and patched conics allowed the fast transfer of the Apollo’s to our natural satellite in less than four days, and proved to be the only option for manned missions. However, we are now in an epoch in which robotic missions dominate the exploration of our planetary system and in particular in a historical and economical moment in which in many situations "cost-efficient" is preferred to "time-efficient". Many alternative solutions to the Earth-to-Moon transfer problem have been proposed based on dynamical models and assumptions that imply long flight times: it is the case, for example, of the low-energy transfers in the circular restricted three-body problem, where the gravitational influence of the Sun is taken into account by letting the s/c travel as far as the equilibrium points of the Sun-Earth system before flying back to the Earth-Moon system and getting captured by the gravity field of the Moon. In this work we investigate the design of Earth-to-Moon trajectories propelled by the action of solar radiation pressure on a sail. Solar sails have been demonstrated in orbit and are undergoing such a rapid technological development that they are being applied also to the class of nanosatellites with off-the-shelf hardware components. We formulate the trajectory design problem as an optimal control problem. Optimal control is based on the theory of calculus of variations and on the Pontryagin minimum principle. It is an indirect optimization method whose formulation is especially suitable to problems where a control is present (in this case the acceleration produced by the momentum exchange between the solar radiation and the sail), and a cost function (such as the transfer time) is to be minimized in the presence of end-point constraints (such as the conditions for capture at the Moon). Therefore, this work shows how to solve an Earth-to-Moon trajectory with solar sail propulsion applying the optimal control theor

Accurate Analytic Mass-Scale Relations for Dark Matter Haloes of all Masses and Redshifts

CUSP is a powerful formalism that recovers, from first principles and with no free parameter, all the macroscopic properties of dark matter haloes found in cosmological N-body simulations and unveils the origin of their characteristic features. Since it is not restricted by the limitations of simulations, it covers the whole mass and redshift ranges. In the present Paper we use CUSP to calculate the mass-scale relations holding for halo density profiles fitted to the usual NFW and Einasto functions in the most relevant cosmologies and for the most usual mass definitions. We clarify the origin of these relations and provide accurate analytic expressions holding for all masses and redshifts. The performance of those expressions is compared to that of previous models and to the mass-concentration relation spanning more than 20 orders of magnitude in mass at $z=0$ obtained in recent simulations of a 100 GeV WIMP universe.Comment: 16 pages, 14 figures, accepted for publication in MNRA

Transfers between moons with escape and capture patterns via Lyapunov exponent maps

This contribution focuses on the design of low-energy transfers between planetary moons and presents an efficient technique to compute trajectories characterized by desirable behaviors in the vicinities of the departure and destination bodies. The method utilizes finite-time Lyapunov exponent maps in combination with the Moon-to-Moon Analytical Transfer (MMAT) method previously proposed by the authors. The integration of these two components facilitates the design of direct transfers between moons within the context of the circular restricted three-body problem, and allows the inclusion of a variety of trajectory patterns, such as captures, landings, transits and takeoffs, at the two ends of a transfer. The foundations and properties of the technique are illustrated through an application based on impulsive direct transfers between Ganymede and Europa. However, the methodology can be employed to assist in the design of more complex mission scenarios, such as moon tours

Revisión sistemática de diferentes métodos de fitorremediación en suelos contaminados con metales pesados

La fitorremediación se encuentra entre las opciones usadas para minimizar la cantidad de metales pesados en suelos contaminados por ser una técnica económica, la cual consiste en emplear cierto tipo de plantas con la capacidad de acumular metales en tallos, hojas y raíces con el fin de removerlos del suelo. Estas tecnologías tienen muchas ventajas, sobre todo en términos de limpieza y economía, no obstante, solo proporcionan resultados a mediano y largo plazo porque precisan de múltiples ciclos. Debido a ello, esta revisión sistemática bibliográfica se plantea identificar y caracterizar las principales técnicas de fitorremediación empleadas en suelos contaminados por metales pesados; con el fin de encontrar coincidencias entre todas ellas y así pueda contribuir como proyecto para dar soluciones alternativas. El método adoptado fue realizar una revisión bibliográfica sistemática usando palabras claves en la búsqueda de bases de datos indexados con acceso libre Scielo, Redalyc Académico, Open Journal Systems, Microsoft Academic, Web of Science, y Google Analytics Academy. Se analizaron más de 60 artículos correspondientes al periodo 2011– 2020. De acuerdo a ello, este estudio se plantea con la finalidad de recopilar los estudios de métodos de fitorremediación empleados en la remediación de suelos contaminados con metales pesados para establecer una relación entre la especie vegetal utilizada y la técnica empleada, con lo cual permitirá identificar necesidades futuras de investigación en cuanto a este asunto. En tal sentido, el estudio realizado muestra que de todas las técnicas analizadas la que tuvo más efectividad fue la fitoextracción y las especies vegetales más concurrentes fueron: las de la familia Fabaceae y las de la familia Brassicaceae, las cuales alcanzaron remociones de cobre (Cu), cinc (Zn), arsénico (As), plomo (Pb) y cadmio (Cd) con máximos de 50% y 60% respectivamente