Hydrodynamic Modeling of Dielectric Response in Graphene and Carbon Nanotubes

This thesis studies two important carbon structures, graphene and carbon nanotubes, with the purpose of understanding how their three-dimensional electron density distribution affects the way fast ions interact with them. A brief introduction to research in pure carbon structures is made. We then use different models to calculate the equilibrium electron density distribution in graphene and carbon nanotubes. In the second part of the thesis we investigate fast ions moving parallel to a graphene sheet and experiencing forces due to the dynamic polarization of carbon valence electrons. Using the three-dimensional electron density distribution of graphene, we calculate the force directly opposing the ion's motion (stopping force), as well as the force which bends the ion's trajectory towards the sheet (image force). It is our purpose to compare these results with those based on a two-dimensional hydrodynamic model of graphene, which approximates the electron distribution of graphene by a charged fluid confined to the two-dimensional plane of the sheet. The results obtained for interactions of ions with a single graphene sheet should be useful for a further analysis of ion channeling through carbon nanostructures

Quantum Plasmonics: A first-principles investigation of metallic nanostructures and their optical properties

The electronic structure and optical properties of metallic nanoparticles are theoretically investigated front first principles. An efficient implementation of time-dependent density functional theory allows a fully quantum mechanical description of systems large enough to display collective electron oscillations and surface plasmon modes. The results are compared with traditional classical electrodynamical approaches. Different regimes of interest are identified, both where classical electrodynamical models yield accurate descriptions, and where quantum effects are indispensable for understanding plasmonic properties in nanostructures. The limits of validity of classical electrodynamics are clearly established for the study of a variety of relevant geometries

La Protección Jurídica de la Libertad Sexual en Cuba y España. Retos del Enfoque de Género en el Contexto de Reformas Penales

El modelo de justicia penal imperante en las sociedades contemporáneas, independientemente del sistema de Derecho al que responda, comparte rasgos comunes esencialmente patriarcales. En tal sentido, el presente artículo valora la protección jurídica de la libertad sexual en los contextos de reformas penales de Cuba y España desde la perspectiva de género. A tales fines, se emplearon los métodos de análisis jurídico-doctrinal, jurídico-sociológico y la comparación jurídica. Los resultados apuntan a la revisión de los Códigos Penales cubano y español en pos de una inminente reforma legal que proporcione una respuesta más adecuada a las realidades delictivas sufridas por las mujeres. Se analiza la configuración del delito de violación en Cuba y las figuras penales de abuso y agresión sexual en España, con especial referencia a la demostración del consentimiento de la víctima. La propuesta está encaminada a la introducción de la perspectiva de género y a la eliminación de los parámetros sexistas en el derecho punitivo, tanto en el ámbito legal como en los escenarios de interpretación judicial

La Protección Jurídica de la Libertad Sexual en Cuba y España. Retos del Enfoque de Género en el Contexto de Reformas Penales

El modelo de justicia penal imperante en las sociedades contemporáneas, independientemente del sistema de Derecho al que responda, comparte rasgos comunes esencialmente patriarcales. En tal sentido, el presente artículo valora la protección jurídica de la libertad sexual en los contextos de reformas penales de Cuba y España desde la perspectiva de género. A tales fines, se emplearon los métodos de análisis jurídico-doctrinal, jurídico-sociológico y la comparación jurídica. Los resultados apuntan a la revisión de los Códigos Penales cubano y español en pos de una inminente reforma legal que proporcione una respuesta más adecuada a las realidades delictivas sufridas por las mujeres. Se analiza la configuración del delito de violación en Cuba y las figuras penales de abuso y agresión sexual en España, con especial referencia a la demostración del consentimiento de la víctima. La propuesta está encaminada a la introducción de la perspectiva de género y a la eliminación de los parámetros sexistas en el derecho punitivo, tanto en el ámbito legal como en los escenarios de interpretación judicial

Contabilidad general: cuaderno de trabajo

Proporciona a los estudiantes un recurso de aprendizaje, donde se plantea diversos ejercicios/ casos por cada tema desarrollado en el curso, para que ellos los resuelvan gradualmente durante el ciclo, con la siguiente finalidad: Refuercen lo aprendido en clase y lo adquirido mediante lectura de los libros texto del curso. Igualmente, que Identifiquen oportunidades de mejora en su aprendizaje

Cartas al editor

Cartas al Doctor Álvaro Rodríguez Gama, Editor de la Revista de la Facultad de Medicin

Soluble iron nutrients in Saharan dust over the central Amazon rainforest

The intercontinental transport of aerosols from the Sahara desert plays a significant role in nutrient cycles in the Amazon rainforest, since it carries many types of minerals to these otherwise low-fertility lands. Iron is one of the micronutrients essential for plant growth, and its long-range transport might be an important source for the iron-limited Amazon rainforest. This study assesses the bioavailability of iron Fe(II) and Fe(III) in the particulate matter over the Amazon forest, which was transported from the Sahara desert (for the sake of our discussion, this term also includes the Sahel region). The sampling campaign was carried out above and below the forest canopy at the ATTO site (Amazon Tall Tower Observatory), a near-pristine area in the central Amazon Basin, from March to April 2015. Measurements reached peak concentrations for soluble Fe(III) (48 ng m−3), Fe(II) (16 ng m−3), Na (470 ng m−3), Ca (194 ng m−3), K (65 ng m−3), and Mg (89 ng m−3) during a time period of dust transport from the Sahara, as confirmed by ground-based and satellite remote sensing data and air mass backward trajectories. Dust sampled above the Amazon canopy included primary biological aerosols and other coarse particles up to 12 µm in diameter. Atmospheric transport of weathered Saharan dust, followed by surface deposition, resulted in substantial iron bioavailability across the rainforest canopy. The seasonal deposition of dust, rich in soluble iron, and other minerals is likely to assist both bacteria and fungi within the topsoil and on canopy surfaces, and especially benefit highly bioabsorbent species. In this scenario, Saharan dust can provide essential macronutrients and micronutrients to plant roots, and also directly to plant leaves. The influence of this input on the ecology of the forest canopy and topsoil is discussed, and we argue that this influence would likely be different from that of nutrients from the weathered Amazon bedrock, which otherwise provides the main source of soluble mineral nutrients

The Amazon Tall Tower Observatory (ATTO): Overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. In this paper, we discuss the scientific context of the ATTO observatory and present an overview of results from ecological, meteorological, and chemical pilot studies at the ATTO site. © Author(s) 2015

Hydrodynamic Modeling of Dielectric Response in Graphene and Carbon Nanotubes

presented to the University of Waterlo

La protección jurídica de la libertad sexual en Cuba y España. Retos del enfoque de género en el contexto de reformas penales

The criminal justice model prevailing in contemporary societies, regardless of the law system to which it responds, shares essentially patriarchal common features. In this regard, this article bases the challenges of legal protection of sexual freedom in the context of criminal reforms in Cuba and Spain from a gender perspective. For these purposes, the methods of legal-doctrinal, legal-sociological analysis and legal comparison were used. The results point to the revision of the Cuban and Spanish Criminal Codes in pursuit of an imminent reform that provides a more adequate response to the criminal realities suffered by women. The article analyzes the configuration of the crime of rape in Cuba and the criminal figures of sexual abuse and assault in Spain, with special reference to the demonstration of the victim's consent. The proposal is aimed at the introduction of the gender perspective and the elimination of sexist parameters in punitive law, both in the legal field and in the scenarios of judicial interpretation.El modelo de justicia penal imperante en las sociedades contemporáneas, independientemente del sistema de Derecho al que responda, comparte rasgos comunes esencialmente patriarcales. En tal sentido, el presente artículo valora la protección jurídica de la libertad sexual en los contextos de reformas penales de Cuba y España desde la perspectiva de género. A tales fines, se emplearon los métodos de análisis jurídico-doctrinal, jurídico-sociológico y la comparación jurídica. Los resultados apuntan a la revisión de los Códigos Penales cubano y español en pos de una inminente reforma legal que proporcione una respuesta más adecuada a las realidades delictivas sufridas por las mujeres. Se analiza la configuración del delito de violación en Cuba y las figuras penales de abuso y agresión sexual en España, con especial referencia a la demostración del consentimiento de la víctima. La propuesta está encaminada a la introducción de la perspectiva de género y a la eliminación de los parámetros sexistas en el derecho punitivo, tanto en el ámbito legal como en los escenarios de interpretación judicial