La poesía de Harold Alvarado Tenorio: notas de situación.

Sin resume

Diseño de nanomateriales mediante procesos de molienda mecanoquímica para aplicaciones catalíticas y electroquímicas

The present doctoral thesis project deals with the design of nanomaterials with potential applications in two important fields: 1) the design of energy storage devices and 2) heterogeneous catalysis, in both cases for the development of more sustainable processes that contribute to ameliorate climate change. Today, most of the challenges humanity faces are related to energy and environment, including the scarcity of water and resources, energy requirements and the depletion of fossil fuel sources. In particular, energy demands, whether in the transport sector or for stationary applications, are priorities in all the scientific programs and agendas of the world. Hence, many investigations are currently aimed to find new materials with better electrochemical results for the development of a new generation of sustainable energy storage devices. In addition, the development of a more sustainable chemical industry requires high efficient processes and therefore the preparation of active and selective catalytic systems. Mechanochemical methods have been employed in this doctoral thesis for the design of nanomaterials, including various nanobioconjugates based on proteins and magnetic nanoparticles, as well as metal oxide nanoparticles supported on mesoporous supports and biomass-templated metal oxide nanomaterials. Mechanochemistry offers several advantages regarding its high reproducibility, versatility, simplicity and, specially, to its green character related to the possibility to avoid the use of solvents and additional reagents. Studies on mechanochemistry have greatly increased in the past two decades, nonetheless as an open research line, a lot of efforts still need to be devoted in order to take full advantages of its great potentialities. Biomass valorization has been one of the main issues covered in this thesis, towards both chemicals and materials. Biomass constitutes, together with CO2, one of the most abundant renewable carbon sources. Therefore, the use of biomass-derived platform molecules for the preparation of added-value chemicals, replacing the petro-based chemical industry, is a highly attractive option. In particular, along this thesis, biomass derived platform molecules such as levulinic acid and isoeugenol have been employed for the synthesis of Nheterocycles and vanillin, respectively. It is important to highlight that, through the valorisation of biomass, added value materials can be also obtained, representing an environmentally friendly methodology. In this regard,, several biomass residues, including spent coffee grounds, egg-white form expired eggs and orange peel have been treated by mechanochemical protocols for the preparation of nanostructured materials with controlled morphology and textural properties. In particular, through this work a mechanochemical synthetic strategy have been designed for the preparation of bioconjugates, minimizing reaction times and costs associated with the use of solvents and other reactants. As an alternative to inorganic materials, organic electroactive products, such as proteins have opened new opportunities for the design of innovative energy storage devices with a greater theoretical capacity, safety, sustainability and low cost. Rechargeable batteries and electrochemical supercapacitors (ECs) are among the most representative examples of energy storage devices. The construction of ECs with high energy density and high power has become a priority issue for the development of future devices. Research in this field has focused on the synthesis of active porous nanomaterials such as metal oxides, hydroxides, or carbonbased materials. These materials provide a high capacity, but have several disadvantages including high costs, manufacturing stages, difficult scalability, besides not being respectful with the environment. In order to overcome the inherent drawbacks of conventional inorganic materials, metalloproteins containing heme groups have recently been employed. However, the development of hybrid systems of hemoproteins and nanoparticles (NPs) for the design of sustainable supercapacitors has not yet been deeply investigated, being a highly innovative and relevant idea for the design of materials that could become a potentially applicable product. Therefore, this doctoral thesis also aimed to synthesize hybrid nanostructures of metalloproteins and nanoparticles through a mechanochemical methodology, as a cheap, sustainable, and versatile strategy, for the design of a new generation of electrochemical supercapacitors. Another potential application of these hybrid protein-nanoparticle systems is their use in biomimetic catalysis processes. Inspired by the in vivo synthesis of natural polymers, where enzymes play an important role as catalysts, in vitro enzymatic polymerization has been widely developed to design a wide range of advanced materials. In particular in this project, bioconjugates based on hemoproteins have been used for the preparation of fluorescent carbon-based nanoparticles following a bottom-up strategy. Similarly, carbon quantum dots with fluorescent behavior have been prepared by a top-down metholody from biomass residues and using an iron oxide containing material as catalyst. In summary, mechanochemistry, as a powerful tool, has been successfully employed to produce a wide range of nanomaterials, from bioconjugates to metal oxides, with applications in catalysis and energy storage. Taking into account the above mentioned premises, the objectives of the proposed work are very relevant for the development of a Sustainable Chemistry and to integrate the strategies of Green Chemistry and Engineering

De poetas venezolanas y del lector que soy (pliego de descargo)

After his essay, El barco de la luna (2005), the author proposes once more a reading of poetry written by women, neither feminin nor feminist, that he thinks these are very reductive terms. So, he offers some reasons as a reader to open a dialogue about the difference of attitude and disposition established by women in literature; in this case, poetesses from Venezuela. Finally, the author puts on focus some voices, better than writings, which are usually in the margin but from there they cause such an uneasiness in the poetry as an ordinary rule.Tras su ensayo El barco de la luna (2005), el autor insiste en la lectura de la poesía escrita por mujeres, fuera de esa reducción que imponen los términos femenino o feminista. Da sus razones de lector y abre diálogo en torno a esa diferencia -de actitud y de disposición que la mujer establece, ahora en las poetas venezolanas. Trae desde el margen al centro aquellas voces que considera crean desconcierto en la escritura poética habitual

Sobre la lectura de Cantos de vida y esperanza y otras cosas

Cantos de vida y esperanza unites life and song in a confrontation of two different concepts of time, through which life becomes part of the conflict of writing, leading to the question: is this an ephemeral problem? Is this radical duality not the basis of Spanish American identity, and for that reason was the exuberant imagery of Darío’s beginnings not a way of putting into literary practice this very existential and social conflict as a consequence of a reflection that the poet never eluded? And was it not, at the same time, a personal affirmation of self in the poetic worldview? The article rereads Cantos de vida y esperanza as the book in which experience strives to reveal itself in everyday reality, as a result of Modernism’s aspiration towards «rebellion» and of poetry as a search for being and saying.Cantos de vida y esperanza une la vida y el canto, confrontación de dos tiempos diferentes, y con ello la vida se incorpora al conflicto de la escritura, por ello la pregunta: ¿es cosa tan sólo de ese momento; no es ésa la doblez radical que determina la identidad hispanoamericana, y por eso fue también el imaginario desaforado del principio una forma de realizar literariamente el mismo conflicto existencial y social, como consecuencia de una reflexión nunca eludida; no era aquélla, además, una afirmación personal del ser en la visión poética del mundo? Volver a leerlo como el poemario en el que la experiencia se quiere desvelar en la realidad inmediata, consecuencia del objetivo del modernismo en tanto «rebeldía» y de la poesía como tentativa del ser y del decir

Jorge Eduardo Eielson: «Poesia Scritta».

Sin resume

Etapas del proceso pedagógico

Como resultado de varias investigaciones realizadas en el campo de acción de la Didáctica y de la propia experiencia docente en diversos niveles educacionales, se puede presentar una propuesta de sucesión de etapas para gestionar el aprendizaje, que deben ser tomadas en consideración para alcanzar resultados satisfactorios en el proceso pedagógico. Estas etapas son seis y se encuentran estrechamente interrelacionadas, su atención consciente en el desarrollo del proceso pedagógico permitirá el mejoramiento del aprendizaje en cualquier área del conocimiento

Respuesta al caso clínico del número anterior

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CARACTERISTICAS DEL CONSUMO DEL CAFÉ (Coffea sp.) MEXICANO DE ESPECIALIDAD EN TILBURG, PAÍSES BAJOS

The growing market of differentiated and specialty coffees is an alternative to the crisis of low aromatic prices. Aggregatevalue allows producers to venture into new markets and obtain better prices. Research was carried out about the factorsthat influence the consumption of specialty coffees and Mexican coffee in the city of Tilburg, the Netherlands, and ananalysis was carried out to identify the strategies applicable in Mexico to promote the consumption of high quality coffees.El creciente mercado de los cafés diferenciados y de especialidad está siendo una alternativa a la crisis de los bajosprecios del aromático. La agregación de valor permite a los productores incursionar en nuevos mercados y obtenermejores precios. Se realizó una investigación acerca de los factores que influyen en el consumo de cafés de especialidady café mexicano en la ciudad de Tilburg, Países Bajos y se efectuó un análisis para identificar las estrategias aplicables enMéxico para promover el consumo de cafés de mejores calidades