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Search Results: 1 - 10 of 448372 matches for " Gloria I. Cárdenas-Jirón "
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AZA NITROGENS EFFECT ON THE ELECTRONIC PROPERTIES OF COBALT PORPHYRINE AND DERIVATIVES
Cárdenas-Jirón,Gloria I.;
Journal of the Chilean Chemical Society , 2004, DOI: 10.4067/S0717-97072004000100017
Abstract: a set of electronic properties calculated at the b3lyp/lacvp(d) level of theory for four cobalt macrocycles containing a ligand like porphyrin (cop) and a benzoporphyrin (cotbp) has been analyzed. the effect of aza nitrogen atoms (aza-n) present in the ligand (cotap, copc) on the electronic properties chosen has been studied. for the pair cop/cotap we found a notorious effect of the presence of aza-n atoms in each electronic property studied. however, for the pair cotbp/copc a different result was obtained. the dipole moment and the atomic charges, the latter evaluated on the cobalt atom and on the aza-n atoms, do not show the isolated effect of the aza nitrogen atoms and rather it appears to be mixed with the effect produced by the ligand size. on the contrary, electronic properties such as spin density and electrostatic potential evaluated on the cobalt atom clearly show the effect of the aza nitrogen atoms predicting that the latter present an electron withdrawing behavior in this kind of molecules
AZA NITROGENS EFFECT ON THE ELECTRONIC PROPERTIES OF COBALT PORPHYRINE AND DERIVATIVES
Gloria I. Cárdenas-Jirón
Journal of the Chilean Chemical Society , 2004,
Abstract: A set of electronic properties calculated at the B3LYP/LACVP(d) level of theory for four cobalt macrocycles containing a ligand like porphyrin (CoP) and a benzoporphyrin (CoTBP) has been analyzed. The effect of aza nitrogen atoms (aza-N) present in the ligand (CoTAP, CoPc) on the electronic properties chosen has been studied. For the pair CoP/CoTAP we found a notorious effect of the presence of aza-N atoms in each electronic property studied. However, for the pair CoTBP/CoPc a different result was obtained. The dipole moment and the atomic charges, the latter evaluated on the cobalt atom and on the aza-N atoms, do not show the isolated effect of the aza nitrogen atoms and rather it appears to be mixed with the effect produced by the ligand size. On the contrary, electronic properties such as spin density and electrostatic potential evaluated on the cobalt atom clearly show the effect of the aza nitrogen atoms predicting that the latter present an electron withdrawing behavior in this kind of molecules
Enfoques metodologicos de la planificación urbana y del transporte. 1980 - 1999
Luz Alicia Cárdenas Jirón
Urbano , 2005,
Abstract:
La "capacidad vial" del plan regulador chileno, es lo suficientemente buena para dar forma a un entorno edificado sostenible?/ The "road capacity" of the chilean master plan is it good enough for shaping a sustainable built environment?
Cárdenas Jirón, Luz Alicia
Revista de Urbanismo , 2000, DOI: doi: 10.5354/0717-5051.2000.12310
Abstract: The "road capacity" of the Chilean Master Plan is a tool developed to measure the capacity of streets in terms of supporting the size of vehicle flow. This tool considers topics such as land use, population density and street width. The purpose of this technique is to incorporate it to the Master Plan, as a town planning instrument, so as to cope with traffic forecasting and congestion. However, the technique does not embrace any sustainability concept, this is due to a disregard of any district ′s social or environmental needs. Therefore a sustainable urban development would doubtfully be reached. It is argued that some other approaches are required for shaping a sustainable built environment in which it is understood that the streets are a public space for people rather than a platform for moving vehicles only. This means, to promote accessibility as well as mobility. In this paper the author reviews borrowed concepts such as "carrying capacity" and "environmental capacity" from bioregionalist and ecological disciplines using a case study in outskirts of Santiago′s metro area./La "capacidad vial" del Plan Regulador chileno es una herramienta desarrollada para medir la capacidad de las calles en términos de apoyar el tama o del flujo de vehículos. Esta herramienta considera temas como el uso de la tierra, la densidad de población y ancho de la calle. El propósito de esta técnica es su incorporación al Plan Maestro, como un instrumento de planificación de la ciudad, con el fin de hacer frente a la previsión del tráfico y la congestión. Sin embargo, la técnica no incluye ningún concepto de sostenibilidad. Por lo tanto un desarrollo urbano sostenible dudosamente sería alcanzado. Se argumenta que algunos otros enfoques son necesarios para dar forma a un medio ambiente sostenible integrado, en el que se entiende que las calles son un espacio público para las personas en lugar de una plataforma para mover los vehículos solamente. Esto significa, para promover la accesibilidad y la movilidad. En este trabajo la autora revisa conceptos prestados, tales como "la capacidad de carga" y "capacidad ambiental", desde el bioregionalist y disciplinas ecológicas mediante un estudio de caso en las afueras del área metropolitana de Santiago de Chile.
La forma urbana del medio ambiente construido: Hacia una propuesta de estructuración para el instrumento Plan Regulador Comunal. / The urban form of the built environment: towards a proposed structure for the instrument Communal Regulating Plan.
Cárdenas Jirón, Luz Alicia
Revista de Urbanismo , 2000, DOI: doi: 10.5354/0717-5051.2000.11776
Abstract: La forma urbana del medio ambiente construido es el elemento central de este artículo, abordado desde dos perspectivas: en primer lugar la crítica de la forma urbana resultante de un instrumento de planificación y en segundo lugar una propuesta de estructuración de la forma urbana para el Plan Regulador Comunal. Con este objeto, se presenta un modelo cartográfico para entregar una pauta metodológica de los aspectos relevantes a la forma urbana que debieran tomarse en cuenta al momento de planificar y gestionar la ciudad. /The urban form of the built environment is the core element of this article. Two approaches have been developed to deal with it, firstly, a criticism of the urban form as a result of the town planning instrument and secondly a proposal to structure the urban form for Plan Regulador Comunal. Given that a cartographic model is showed as an example to deal with relevant issues in relation to the urban form. The model tries to give a methodological guide to the urban planners and managers.
Definición de un marco teórico para comprender el concepto del desarrollo sustentable./Definition of a theoretical framework for understanding the concept of sustainable development.
Cárdenas Jirón; Luz Alicia
Revista de Urbanismo , 1999, DOI: doi: 10.5354/0717-5051.1999.11746
Abstract: Dado el actual requerimiento por comprender un concepto tan recurrente en el campo profesional, académico y político como es el Desarrollo Sustentable, es que ocurre la elaboración de este articulo. Por tanto lo que se pretende lograr es aclarar el significado conceptual del Desarrollo Sustentable, situarlo en un contexto, entender el proceso gestacional e ilustrar con algún ejemplo clásico Latinoamericano./It contributes to the understanding of the concept of sustainable development. First, referring to a global political context existing economic in the second half of this century. Then develops a theoretical framework for the meaning and the different approaches related to sustainable development. From this, it raises agendas to realize and move towards this type of development, which emphasize the local level as a solid starting point. Shows the case of the city of Curitiba, with proper planning and sustainable management recognized.
Urban form at the fringe of Metropolitan Santiago. A result of a normative or profitability plan?. / La forma urbana en la periferia del área metropolitana de Santiago. La consecuencia de una normativa o plan de rentabilidad?
Cárdenas Jirón, Luz Alicia,Mawromatis, Constantino
Revista de Urbanismo , 1999, DOI: doi: 10.5354/0717-5051.1999.11755
Abstract: Metropolitan Santiago is one of the many Latin American cities which has been developed according to a spread model of urbanisation. This pattern has caused at least two types of consequences: economic and physical ones. The former is shown in the speculation of land value at the rural fringe of the metropolitan area which has low prices, these have suddenly increased after the normative changes in the land use, from rural to urban. The later shows location of massive low-income housing and commercial malls regardless connection to the urban fabric and spatial shaping of the existing city. This results in a chaotic urban form resembling a "patchwork".This paper reviews the scope of a Chilean policy instrument called "Plan Regulador" used to control physical urban growth, particularly sprawled on the fringe of the city. It is believed that as a consequence of this Plan, normative procedures are not good enough for achieving its objectives. Conversely, urban form appears to be a result of a profitability plan made by private developers. Given the weakness of this instrument, some recommendations related to spatial models are suggested to incorporate to or complement the "Plan Regulador"./ El Plan Regulador Comunal es el instrumento normativo de planeación urbanística chilena, cuya formulación pretende regular en el ámbito comunal básicamente los siguientes aspectos: los usos de suelo, las condiciones de edificación y subdivisión del suelo, la red vial estructurante y los limites urbanos.Se cree que este instrumento es imperfecto toda vez que no incorpora en la normativa una dimensión clave del urbanismo: la morfología urbana, entendida como el sistema espacial tridimensional de la ciudad. Por el contrario, el análisis empírico demuestra que factores como la forma urbana son respuestas del libre juego de fuerzas económicas y sociales modeladoras del espacio. En consecuencia, lo que domina es un patrón de urbanización en vez de un proyecto de urbanismo; las cuales son modalidades muy distintas de hacer ciudad.Este articulo pretende demostrar que la forma urbana, derivada de la aplicación del instrumento normativo en una comuna perimetral metropolitana como es Maipú, es uno de los impactos no previstos por el Plan Regulador, pero que podría incorporarse en un nuevo instrumento de planificación urbana./
Acceso solar a las edificaciones. El eslabón pendiente en la norma urbanística chilena sobre la actividad proyectual. / Solar access to buildings. The unsolved link in Chile’s urban laws regarding architectural design activity.
Luz Alicia Cárdenas Jirón,Paula Uribe Araya
Revista de Urbanismo , 2012, DOI: doi: 10.5354/0717-5051.2012.20922
Abstract: Hoy en día las demandas energéticas y la búsqueda de fuentes renovables no contaminantes, tales como las Energías Renovables No Convencionales ERNC, son cada vez más acuciantes en el mundo. Entre ellas está la energía solar, cuya captación adquiere una importancia crucial en el medio urbano, debido a obstrucciones provenientes de las morfologías resultantes de la dinámica inmobiliaria. No obstante, se plantea que la vinculación entre morfología urbana y captación solar por edificaciones para sistemas activos, no ha sido abordada en el medio nacional. El objetivo de este artículo es reflexionar respecto a un concepto clave en estas materias: el acceso solar,porque se transforma en un bien muy preciado y necesario resguardar para el bien común. El enfoque adoptado analiza dos marcos normativos convergentes a la actividad proyectual energética solar: la Ordenanza General de Urbanismo y Construcciones (OGUC)) y la Ley del Net Metering (NM). Se analiza la aplicación de la normativa OGUC en un caso hipotético, sus implicancias en las sombras arrojadas sobre edificaciones, predios y espacios públicos. El resultado final es la contextualización espacial de un problema detectado entre forma urbana y energía solar, conducente a develar un eslabón pendiente en la normativa chilena sobre actividad proyectual./Nowadays energy demand and searching for renewable no polluted source such as Renewable Energy No Conventional (ERNC) has become crucial in the world. Solar energy is one of them whose insolation has a key importance in the built environment because obstructions comingfrom ending morphology of the real estate./ Although that it is stated that link between urban morphology and building insolation for active systems has not yet been tackled in the national legislation. The objective of the article is to think about a key concept: solar access because it is relevant for equity viewpoint. The paperfocus on two legislative frameworks embodied to solar urbanism design and power such as Ordenanza General de Urbanismo (OGUC) and Net Metering Law (NM). To demonstrate unlink a hypothetical case is studied for its implications on buildings, allotment and public space. Final result is putting on ground a spatial problem between urban form and solar energy leading to reveal unsolved link in the Chilean urbanism normative.
Globalización en Copiapó, Chile: aplicación de un modelo económico orientado a las exportaciones frutícolas/ Copiapó and its globalization: a fruit export-oriented model
Cárdenas Jirón, Luz Alicia,Carrasco Milla, Pablo
Revista de Urbanismo , 2008, DOI: doi: 10.5354/0717-5051.2008.237
Abstract: Este artículo da cuenta de una investigación que tiene por objeto evaluar cambios en la estructura urbana de ciudades de rango medio insertas en la economía global. Se escoge Copiapó por el espectacular crecimiento económico derivado del modelo orientado a las exportaciones frutícolas de uva de mesa, que constituyó la nueva base económica de una región tradicionalmente minera y semiárida del norte chileno. Luego de 30 a os de aplicación del modelo se analizan los cambios en la ciudad y el territorio empleando referentes conceptuales propios del proceso tales como: los “servicios de producción avanzada” y los “artefactos de globalización”./The current paper disseminates research results. Its purpose was to evaluate changes in urban structure of medium-size cities which are involved in the global economy. Copiapó was selected because of its spectacular economic growth supported by grapes table export-oriented model. Then grapes table become a new economic base in a traditional mining and semi-arid region in the Chilean northern. Changes on cities and territory were examined after 30 years of applying model. Conceptual references from globalization framework were applied such as “advanced production services” and “globalization artifacts”.
Thiol/Disulfide System Plays a Crucial Role in Redox Protection in the Acidophilic Iron-Oxidizing Bacterium Leptospirillum ferriphilum
Javiera Norambuena, Rodrigo Flores, Juan P. Cárdenas, Raquel Quatrini, Renato Chávez, Gloria Levicán
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044576
Abstract: Thiol/disulfide systems are involved in the maintenance of the redox status of proteins and other molecules that contain thiol/disulfide groups. Leptospirillum ferriphilum DSM14647, an acidophilic bacterium that uses Fe2+ as electron donor, and withstands very high concentrations of iron and other redox active metals, is a good model to study how acidophiles preserve the thiol/disulfide balance. We studied the composition of thiol/disulfide systems and their role in the oxidative stress response in this extremophile bacterium. Bioinformatic analysis using genomic data and enzymatic assays using protein extracts from cells grown under oxidative stress revealed that the major thiol/disulfide system from L. ferriphilum are a cytoplasmic thioredoxin system (composed by thioredoxins Trx and thioredoxin reductase TR), periplasmic thiol oxidation system (DsbA/DsbB) and a c-type cytochrome maturation system (DsbD/DsbE). Upon exposure of L. ferriphilum to reactive oxygen species (ROS)-generating compounds, transcriptional activation of the genes encoding Trxs and the TR enzyme, which results in an increase of the corresponding activity, was observed. Altogether these data suggest that the thioredoxin-based thiol/disulfide system plays an important role in redox protection of L. ferriphilum favoring the survival of this microorganism under extreme environmental oxidative conditions.
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