Políticas urbanas de la Unión Europea desde la perspectiva de la planificación colaborativa: Las Iniciativas Comunitarias URBAN y URBAN II en España

Este trabajo lleva a cabo un análisis de la aportación que las políticas urbanas de la Unión Europea (UE), y en particular las dos fases de la Iniciativa Comunitaria URBAN2, han hecho a la práctica de la regeneración urbana en España desde la perspectiva de la Planificación Colaborativa. La adopción de la Planificación Colaborativa como marco conceptual ha provisto la base teórica, el punto de vista e hilo conductor desde el que se ha analizado la dimensión urbana de las políticas comunitarias, poniendo el foco específicamente en URBAN, a través de la realización de un estudio que ha profundizado en el contexto histórico y el debate teórico desde los que se pusieron las bases metodológicas de esta forma de incidir en la degradación urbana, propuesta por la Comisión Europea en 1994. Esto ha llevado a profundizar en el escenario británico de la regeneración urbana, en el que la investigación ha encontrado la referencia sobre la que en gran medida se gestó esta Iniciativa Comunitaria. El trabajo descrito ha permitido caracterizar URBAN como un instrumento de regeneración urbana que conlleva la asunción de un enfoque colaborativo, que en última instancia tiene como objetivo la transformación de la gobernanza. Asimismo, ha sentado las bases sobre las que se ha fundamentado el análisis de la materialización de la dimensión colaborativa de los programas URBAN y URBAN II implementados en España. Los resultados alcanzados por los programas, considerados a la luz de la profundización en la práctica de la regeneración urbana del país, han permitido llegar a conclusiones sobre la aportación que la dimensión colaborativa de URBAN ha hecho al contexto español y señalar un conjunto de líneas de investigación que suponen la continuación del camino emprendido por esta Tesis Doctoral. Summary This work analyses the contribution that the urban policy of the European Union (EU), and in particular the two rounds of the URBAN Community Initiative3, as its most especific instrument, have made to the urban regeneration practice in Spain from the perspective of Collaborative Planning. The adoption of Collaborative Planning as a conceptual framework has provided the theoretical base, the focus and the guiding principle from which to analyse the urban dimension of European policies, and particularly URBAN, through the development of a study that has delved into the historical context and the theoretical debate that laid the methodological foundations of this approach to fight urban degradation launched by the European Commission in 1994. This has included the study of the British scenario of urban regeneration, in which the research has found the reference point on which URBAN was largely conceived. The work described has allowed this Community Initiative to be characterised as a tool of urban regeneration which involved the adoption of a collaborative approach, whose ultimate aim was the transformation of governance. It has also laid the foundations on which the analysis of the implementation of the collaborative approach in the URBAN and URBAN II programmes developed in Spain has been based. The results attained by the programmes considered in light of the development of the practice of urban regeneration in the Spanish scenario, have led to conclusions about the contribution that the collaborative dimension of URBAN has made to the Spanish context and have resulted in the identification of a number of lines of research that represent the continuation of the path taken by this Thesis.

Climate and grazing control nurse effects in an Ecuadorian dry shrubby community

Positive plant interactions have strong effects on plant diversity at several spatial scales, expanding species distribution under stressful conditions. We evaluated the joint effect of climate and grazing on the nurse effect of Croton wagneri, by monitoring several community attributes at two spatial scales: microhabitat and plant community. Two very close locations that only differed in grazing intensity were surveyed in an Ecuadorian dry scrub ecosystem. At each location, two 30 × 30-m plots were established at four altitudinal levels (1500, 2630, 1959 and 2100 m asl) and 40 microsites were surveyed in each plot. Croton wagneri acted as community hubs, increasing species richness and plant cover at both scales. Beneath nurses mean richness and cover values were 3.4 and 21.9%, and in open areas 2.3 and 4.5%, respectively. Magnitude of nurse effect was dependent on climate and grazing conditions. In ungrazed locations, cover increased and diversity reduced with altitude, while grazed locations showed the opposite trend. In ungrazed plots the interactions shifted from positive to negative with altitude, in grazed locations interactions remained positive. We conclude that the nurse effect is a key mechanism regulating community properties not only at microsite but also at the entire community scale.

Bioaccessibility of metals and human health risk assessment in community urban gardens

Pseudo-total (i.e. aqua regia extractable) and gastric-bioaccessible (i.e. glycine + HCl extractable) concentrations of Ca, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in a total of 48 samples collected from six community urban gardens of different characteristics in the city of Madrid (Spain). Calcium carbonate appears to be the soil property that determines the bioaccessibility of a majority of those elements, and the lack of influence of organic matter, pH and texture can be explained by their low levels in the samples (organic matter) or their narrow range of variation (pH and texture). A conservative risk assessment with bioaccessible concentrations in two scenarios, i.e. adult urban farmers and children playing in urban gardens, revealed acceptable levels of risk, but with large differences between urban gardens depending on their history of land use and their proximity to busy areas in the city center. Only in a worst-case scenario in which children who use urban gardens as recreational areas also eat the produce grown in them would the risk exceed the limits of acceptability

Reversible Urban Entities. Improving public-to-private continuity.

The aim of this paper is to call into question those typologies conventionally used in developing the post-industrial urban fabric (streets, cityblocks, slabs, etc.), often catering to urban designs based on speculative interests and completely overlooking community interests. By defining the concepts of ?postpublic space? and ?reversible urban entities? and illustrating them with an exemplary case of Spanish residential architecture from the 1960s, we establish one possible way of tackling contemporary urban-residential projects. This alternative approach considers the relationship between residential systems and open space systems and promotes the continuity and/or alternation of scales between house and city in an effort to improve the urban quality of life for residents and external users.

Assessing urban mobility through participatory scenario building and combined utility-regret assessment

La planificación de la movilidad sostenible urbana es una tarea compleja que implica un alto grado de incertidumbre debido al horizonte de planificación a largo plazo, la amplia gama de paquetes de políticas posibles, la necesidad de una aplicación efectiva y eficiente, la gran escala geográfica, la necesidad de considerar objetivos económicos, sociales y ambientales, y la respuesta del viajero a los diferentes cursos de acción y su aceptabilidad política (Shiftan et al., 2003). Además, con las tendencias inevitables en motorización y urbanización, la demanda de terrenos y recursos de movilidad en las ciudades está aumentando dramáticamente. Como consecuencia de ello, los problemas de congestión de tráfico, deterioro ambiental, contaminación del aire, consumo de energía, desigualdades en la comunidad, etc. se hacen más y más críticos para la sociedad. Esta situación no es estable a largo plazo. Para enfrentarse a estos desafíos y conseguir un desarrollo sostenible, es necesario considerar una estrategia de planificación urbana a largo plazo, que aborde las necesarias implicaciones potencialmente importantes. Esta tesis contribuye a las herramientas de evaluación a largo plazo de la movilidad urbana estableciendo una metodología innovadora para el análisis y optimización de dos tipos de medidas de gestión de la demanda del transporte (TDM). La metodología nueva realizado se basa en la flexibilización de la toma de decisiones basadas en utilidad, integrando diversos mecanismos de decisión contrariedad‐anticipada y combinados utilidad‐contrariedad en un marco integral de planificación del transporte. La metodología propuesta incluye dos aspectos principales: 1) La construcción de escenarios con una o varias medidas TDM usando el método de encuesta que incorpora la teoría “regret”. La construcción de escenarios para este trabajo se hace para considerar específicamente la implementación de cada medida TDM en el marco temporal y marco espacial. Al final, se construyen 13 escenarios TDM en términos del más deseable, el más posible y el de menor grado de “regret” como resultado de una encuesta en dos rondas a expertos en el tema. 2) A continuación se procede al desarrollo de un marco de evaluación estratégica, basado en un Análisis Multicriterio de Toma de Decisiones (Multicriteria Decision Analysis, MCDA) y en un modelo “regret”. Este marco de evaluación se utiliza para comparar la contribución de los distintos escenarios TDM a la movilidad sostenible y para determinar el mejor escenario utilizando no sólo el valor objetivo de utilidad objetivo obtenido en el análisis orientado a utilidad MCDA, sino también el valor de “regret” que se calcula por medio del modelo “regret” MCDA. La función objetivo del MCDA se integra en un modelo de interacción de uso del suelo y transporte que se usa para optimizar y evaluar los impactos a largo plazo de los escenarios TDM previamente construidos. Un modelo de “regret”, llamado “referencedependent regret model (RDRM)” (modelo de contrariedad dependiente de referencias), se ha adaptado para analizar la contribución de cada escenario TDM desde un punto de vista subjetivo. La validación de la metodología se realiza mediante su aplicación a un caso de estudio en la provincia de Madrid. La metodología propuesta define pues un procedimiento técnico detallado para la evaluación de los impactos estratégicos de la aplicación de medidas de gestión de la demanda en el transporte, que se considera que constituye una herramienta de planificación útil, transparente y flexible, tanto para los planificadores como para los responsables de la gestión del transporte. Planning sustainable urban mobility is a complex task involving a high degree of uncertainty due to the long‐term planning horizon, the wide spectrum of potential policy packages, the need for effective and efficient implementation, the large geographical scale, the necessity to consider economic, social, and environmental goals, and the traveller’s response to the various action courses and their political acceptability (Shiftan et al., 2003). Moreover, with the inevitable trends on motorisation and urbanisation, the demand for land and mobility in cities is growing dramatically. Consequently, the problems of traffic congestion, environmental deterioration, air pollution, energy consumption, and community inequity etc., are becoming more and more critical for the society (EU, 2011). Certainly, this course is not sustainable in the long term. To address this challenge and achieve sustainable development, a long‐term perspective strategic urban plan, with its potentially important implications, should be established. This thesis contributes on assessing long‐term urban mobility by establishing an innovative methodology for optimizing and evaluating two types of transport demand management measures (TDM). The new methodology aims at relaxing the utility‐based decision‐making assumption by embedding anticipated‐regret and combined utilityregret decision mechanisms in an integrated transport planning framework. The proposed methodology includes two major aspects: 1) Construction of policy scenarios within a single measure or combined TDM policy‐packages using the survey method incorporating the regret theory. The purpose of building the TDM scenarios in this work is to address the specific implementation in terms of time frame and geographic scale for each TDM measure. Finally, 13 TDM scenarios are built in terms of the most desirable, the most expected and the least regret choice by means of the two‐round Delphi based survey. 2) Development of the combined utility‐regret analysis framework based on multicriteria decision analysis (MCDA). This assessment framework is used to compare the contribution of the TDM scenario towards sustainable mobility and to determine the best scenario considering not only the objective utility value obtained from the utilitybased MCDA, but also a regret value that is calculated via a regret‐based MCDA. The objective function of the utility‐based MCDA is integrated in a land use and transport interaction model and is used for optimizing and assessing the long term impacts of the constructed TDM scenarios. A regret based model, called referente dependent regret model (RDRM) is adapted to analyse the contribution of each TDM scenario in terms of a subjective point of view. The suggested methodology is implemented and validated in the case of Madrid. It defines a comprehensive technical procedure for assessing strategic effects of transport demand management measures, which can be useful, transparent and flexible planning tool both for planners and decision‐makers.

Bioaccessibility of heavy metals and risk assessment in urban gardens of Madrid

Human health problems and solutions. Urban gardening has spread worldwide in recent years as it enhances food security and selfsupply and promotes community integration. However urban soils are significantly enriched in trace elements relative to background levels. Exposure to the soil in urban gardens may therefore result in adverse health effects depending on the degree of contact during gardening, infant recreational activities and ingestion of vegetables grown in them. In order to evaluate this potential risk, 36 composite samples were collected from the top 20 cm of the soil of 6 urban gardens in Madrid. The aqua regia (pseudototal) and glycine-extractable (bioaccessible) concentrations of Co, Cr, Cu, Ni, Pb and Zn were determined by atomic absorption spectrophotometry. Additionally, pH, texture, Fe, Ca, and Mn concentrations, and organic matter and calcium carbonate contents were determined in all urban gardens and their influence on trace element bioaccessibility was analyzed.

Urbanism and dictatorship: perspectives of the field of urban studies

In 1933 public letter to Wilhelm Furtwängler, Joseph Goebbels synthesized the official understanding of the link between politics, art and society in the early steps of the Third Reich. By assuming the ethos of art, politics acquired a plastic agency to mold its objects —population and the state— as a unified entity in the form of a ‘national-popular community’ (Volksgemeinschaft); in turn, by infusing art with a political valence, it became part of a wider governmental apparatus that reshaped aesthetic discourses and practices. Similar remarks could be made about the ordering of cities and territories in this period. Dictatorial imaginations mobilized urbanism —including urban theory, urban design and planning— as a fundamental tool for social organization. Under their aegis the production of space became a moment in a wider production of society. Many authors suggest that this political-spatial nexus is intrinsic to modernity itself, beyond dictatorial regimes. In this light, I propose to use dictatorial urbanisms as an analytical opportunity to delve into some concealed features of modern urban design and planning. This chapter explores some of these aspects from a theoretical standpoint, focusing on the development of dictatorial planning mentalities and spatial rationalities and drawing links to other historical episodes in order to inscribe the former in a broader genealogy of urbanism. Needless to say, I don’t suggest that we use dictatorships as mere templates to understand modern productions of space. Instead, these cases provide a crude version of some fundamental drives in the operationalization of urbanism as an instrument of social regulation, showing how far the modern imagination of sociospatial orderings can go. Dictatorial urbanisms constituted a set of experiences where many dreams and aspirations of modern planning went to die. But not, as the conventional account would have it, because the former were the antithesis of the latter, but rather because they worked as the excess of a particular orientation of modern spatial governmentalities — namely, their focus on calculation, social engineering and disciplinary spatialities, and their attempt to subsume a wide range of everyday practices under institutional structuration by means of spatial mediations. In my opinion the interest of dictatorial urbanisms lies in their role as key regulatory episodes in a longer history of our urban present. They stand as a threshold between the advent of planning in the late 19th and early 20th century, and its final consolidation as a crucial state instrument after World War II. We need, therefore, to pay attention to these experiences vis-à-vis the alleged ‘normal’ development of the field in contemporary democratic countries in order to develop a full comprehension thereof.

Urban wind energy: empirical optimization of high-rise building roof shape for the wind energy exploitation

El programa Europeo HORIZON2020 en Futuras Ciudades Inteligentes establece como objetivo que el 20% de la energía eléctrica sea generada a partir de fuentes renovables. Este objetivo implica la necesidad de potenciar la generación de energía eólica en todos los ámbitos. La energía eólica reduce drásticamente las emisiones de gases de efecto invernadero y evita los riesgos geo-políticos asociados al suministro e infraestructuras energéticas, así como la dependencia energética de otras regiones. Además, la generación de energía distribuida (generación en el punto de consumo) presenta significativas ventajas en términos de elevada eficiencia energética y estimulación de la economía. El sector de la edificación representa el 40% del consumo energético total de la Unión Europea. La reducción del consumo energético en este área es, por tanto, una prioridad de acuerdo con los objetivos "20-20-20" en eficiencia energética. La Directiva 2010/31/EU del Parlamento Europeo y del Consejo de 19 de mayo de 2010 sobre el comportamiento energético de edificaciones contempla la instalación de sistemas de suministro energético a partir de fuentes renovables en las edificaciones de nuevo diseño. Actualmente existe una escasez de conocimiento científico y tecnológico acerca de la geometría óptima de las edificaciones para la explotación de la energía eólica en entornos urbanos. El campo tecnológico de estudio de la presente Tesis Doctoral es la generación de energía eólica en entornos urbanos. Específicamente, la optimization de la geometría de las cubiertas de edificaciones desde el punto de vista de la explotación del recurso energético eólico. Debido a que el flujo del viento alrededor de las edificaciones es exhaustivamente investigado en esta Tesis empleando herramientas de simulación numérica, la mecánica de fluidos computacional (CFD en inglés) y la aerodinámica de edificaciones son los campos científicos de estudio. El objetivo central de esta Tesis Doctoral es obtener una geometría de altas prestaciones (u óptima) para la explotación de la energía eólica en cubiertas de edificaciones de gran altura. Este objetivo es alcanzado mediante un análisis exhaustivo de la influencia de la forma de la cubierta del edificio en el flujo del viento desde el punto de vista de la explotación energética del recurso eólico empleando herramientas de simulación numérica (CFD). Adicionalmente, la geometría de la edificación convencional (edificio prismático) es estudiada, y el posicionamiento adecuado para los diferentes tipos de aerogeneradores es propuesto. La compatibilidad entre el aprovechamiento de las energías solar fotovoltaica y eólica también es analizado en este tipo de edificaciones. La investigación prosigue con la optimización de la geometría de la cubierta. La metodología con la que se obtiene la geometría óptima consta de las siguientes etapas: - Verificación de los resultados de las geometrías previamente estudiadas en la literatura. Las geometrías básicas que se someten a examen son: cubierta plana, a dos aguas, inclinada, abovedada y esférica. - Análisis de la influencia de la forma de las aristas de la cubierta sobre el flujo del viento. Esta tarea se lleva a cabo mediante la comparación de los resultados obtenidos para la arista convencional (esquina sencilla) con un parapeto, un voladizo y una esquina curva. - Análisis del acoplamiento entre la cubierta y los cerramientos verticales (paredes) mediante la comparación entre diferentes variaciones de una cubierta esférica en una edificación de gran altura: cubierta esférica estudiada en la literatura, cubierta esférica integrada geométricamente con las paredes (planta cuadrada en el suelo) y una cubierta esférica acoplada a una pared cilindrica. El comportamiento del flujo sobre la cubierta es estudiado también considerando la posibilidad de la variación en la dirección del viento incidente. - Análisis del efecto de las proporciones geométricas del edificio sobre el flujo en la cubierta. - Análisis del efecto de la presencia de edificaciones circundantes sobre el flujo del viento en la cubierta del edificio objetivo. Las contribuciones de la presente Tesis Doctoral pueden resumirse en: - Se demuestra que los modelos de turbulencia RANS obtienen mejores resultados para la simulación del viento alrededor de edificaciones empleando los coeficientes propuestos por Crespo y los propuestos por Bechmann y Sórensen que empleando los coeficientes estándar. - Se demuestra que la estimación de la energía cinética turbulenta del flujo empleando modelos de turbulencia RANS puede ser validada manteniendo el enfoque en la cubierta de la edificación. - Se presenta una nueva modificación del modelo de turbulencia Durbin k — e que reproduce mejor la distancia de recirculación del flujo de acuerdo con los resultados experimentales. - Se demuestra una relación lineal entre la distancia de recirculación en una cubierta plana y el factor constante involucrado en el cálculo de la escala de tiempo de la velocidad turbulenta. Este resultado puede ser empleado por la comunidad científica para la mejora del modelado de la turbulencia en diversas herramientas computacionales (OpenFOAM, Fluent, CFX, etc.). - La compatibilidad entre las energías solar fotovoltaica y eólica en cubiertas de edificaciones es analizada. Se demuestra que la presencia de los módulos solares provoca un descenso en la intensidad de turbulencia. - Se demuestran conflictos en el cambio de escala entre simulaciones de edificaciones a escala real y simulaciones de modelos a escala reducida (túnel de viento). Se demuestra que para respetar las limitaciones de similitud (número de Reynolds) son necesarias mediciones en edificaciones a escala real o experimentos en túneles de viento empleando agua como fluido, especialmente cuando se trata con geometrías complejas, como es el caso de los módulos solares. - Se determina el posicionamiento más adecuado para los diferentes tipos de aerogeneradores tomando en consideración la velocidad e intensidad de turbulencia del flujo. El posicionamiento de aerogeneradores es investigado en las geometrías de cubierta más habituales (plana, a dos aguas, inclinada, abovedada y esférica). - Las formas de aristas más habituales (esquina, parapeto, voladizo y curva) son analizadas, así como su efecto sobre el flujo del viento en la cubierta de un edificio de gran altura desde el punto de vista del aprovechamiento eólico. - Se propone una geometría óptima (o de altas prestaciones) para el aprovechamiento de la energía eólica urbana. Esta optimización incluye: verificación de las geometrías estudiadas en el estado del arte, análisis de la influencia de las aristas de la cubierta en el flujo del viento, estudio del acoplamiento entre la cubierta y las paredes, análisis de sensibilidad del grosor de la cubierta, exploración de la influencia de las proporciones geométricas de la cubierta y el edificio, e investigación del efecto de las edificaciones circundantes (considerando diferentes alturas de los alrededores) sobre el flujo del viento en la cubierta del edificio objetivo. Las investigaciones comprenden el análisis de la velocidad, la energía cinética turbulenta y la intensidad de turbulencia en todos los casos. ABSTRACT The HORIZON2020 European program in Future Smart Cities aims to have 20% of electricity produced by renewable sources. This goal implies the necessity to enhance the wind energy generation, both with large and small wind turbines. Wind energy drastically reduces carbon emissions and avoids geo-political risks associated with supply and infrastructure constraints, as well as energy dependence from other regions. Additionally, distributed energy generation (generation at the consumption site) offers significant benefits in terms of high energy efficiency and stimulation of the economy. The buildings sector represents 40% of the European Union total energy consumption. Reducing energy consumption in this area is therefore a priority under the "20-20-20" objectives on energy efficiency. The Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings aims to consider the installation of renewable energy supply systems in new designed buildings. Nowadays, there is a lack of knowledge about the optimum building shape for urban wind energy exploitation. The technological field of study of the present Thesis is the wind energy generation in urban environments. Specifically, the improvement of the building-roof shape with a focus on the wind energy resource exploitation. Since the wind flow around buildings is exhaustively investigated in this Thesis using numerical simulation tools, both computational fluid dynamics (CFD) and building aerodynamics are the scientific fields of study. The main objective of this Thesis is to obtain an improved (or optimum) shape of a high-rise building for the wind energy exploitation on the roof. To achieve this objective, an analysis of the influence of the building shape on the behaviour of the wind flow on the roof from the point of view of the wind energy exploitation is carried out using numerical simulation tools (CFD). Additionally, the conventional building shape (prismatic) is analysed, and the adequate positions for different kinds of wind turbines are proposed. The compatibility of both photovoltaic-solar and wind energies is also analysed for this kind of buildings. The investigation continues with the buildingroof optimization. The methodology for obtaining the optimum high-rise building roof shape involves the following stages: - Verification of the results of previous building-roof shapes studied in the literature. The basic shapes that are compared are: flat, pitched, shed, vaulted and spheric. - Analysis of the influence of the roof-edge shape on the wind flow. This task is carried out by comparing the results obtained for the conventional edge shape (simple corner) with a railing, a cantilever and a curved edge. - Analysis of the roof-wall coupling by testing different variations of a spherical roof on a high-rise building: spherical roof studied in the litera ture, spherical roof geometrically integrated with the walls (squared-plant) and spherical roof with a cylindrical wall. The flow behaviour on the roof according to the variation of the incident wind direction is commented. - Analysis of the effect of the building aspect ratio on the flow. - Analysis of the surrounding buildings effect on the wind flow on the target building roof. The contributions of the present Thesis can be summarized as follows: - It is demonstrated that RANS turbulence models obtain better results for the wind flow around buildings using the coefficients proposed by Crespo and those proposed by Bechmann and S0rensen than by using the standard ones. - It is demonstrated that RANS turbulence models can be validated for turbulent kinetic energy focusing on building roofs. - A new modification of the Durbin k — e turbulence model is proposed in order to obtain a better agreement of the recirculation distance between CFD simulations and experimental results. - A linear relationship between the recirculation distance on a flat roof and the constant factor involved in the calculation of the turbulence velocity time scale is demonstrated. This discovery can be used by the research community in order to improve the turbulence modeling in different solvers (OpenFOAM, Fluent, CFX, etc.). - The compatibility of both photovoltaic-solar and wind energies on building roofs is demonstrated. A decrease of turbulence intensity due to the presence of the solar panels is demonstrated. - Scaling issues are demonstrated between full-scale buildings and windtunnel reduced-scale models. The necessity of respecting the similitude constraints is demonstrated. Either full-scale measurements or wind-tunnel experiments using water as a medium are needed in order to accurately reproduce the wind flow around buildings, specially when dealing with complex shapes (as solar panels, etc.). - The most adequate position (most adequate roof region) for the different kinds of wind turbines is highlighted attending to both velocity and turbulence intensity. The wind turbine positioning was investigated for the most habitual kind of building-roof shapes (flat, pitched, shed, vaulted and spherical). - The most habitual roof-edge shapes (simple edge, railing, cantilever and curved) were investigated, and their effect on the wind flow on a highrise building roof were analysed from the point of view of the wind energy exploitation. - An optimum building-roof shape is proposed for the urban wind energy exploitation. Such optimization includes: state-of-the-art roof shapes test, analysis of the influence of the roof-edge shape on the wind flow, study of the roof-wall coupling, sensitivity analysis of the roof width, exploration of the aspect ratio of the building-roof shape and investigation of the effect of the neighbouring buildings (considering different surrounding heights) on the wind now on the target building roof. The investigations comprise analysis of velocity, turbulent kinetic energy and turbulence intensity for all the cases.

Del plan a la realidad: gobernanza y toma de decisiones en los procesos de regeneración urbana. El caso de Boston = From plan to reality: governance and decision-making in urban regeneration processes in Boston

En las últimas tres décadas, las dinámicas de restructuración económica a nivel global han redefinido radicalmente el papel de las ciudades. La transición del keynesianismo al neoliberalismo ha provocado un cambio en las políticas urbanas de los gobiernos municipales, que han abandonado progresivamente las tareas de regulación y redistribución para centrarse en la promoción del crecimiento económico y la competitividad. En este contexto, muchas voces críticas han señalado que la regeneración urbana se ha convertido en un vehículo de extracción de valor de la ciudad y está provocando la expulsión de los ciudadanos más vulnerables. Sin embargo, la regeneración de áreas consolidadas supone también una oportunidad de mejora de las condiciones de vida de la población residente, y es una política necesaria para controlar la expansión de la ciudad y reducir las necesidades de desplazamiento, promoviendo así ciudades más sostenibles. Partiendo de la hipótesis de que la gobernanza de los procesos de regeneración urbana es clave en el resultado final de las operaciones y determina el modelo de ciudad resultante, el objetivo de esta investigación es verificar si la regeneración urbana es necesariamente un mecanismo de extracción de valor o si puede mejorar la calidad de vida en las ciudades a través de la participación de los ciudadanos. Para ello, propone un marco de análisis del proceso de toma de decisiones en los planes de regeneración urbana y su impacto en los resultados de los planes, tomando como caso de estudio la ciudad de Boston, que desde los años 1990 trata de convertirse en una “ciudad de los barrios”, fomentando la participación ciudadana al tiempo que se posiciona en la escena económica global. El análisis se centra en dos operaciones de regeneración iniciadas a finales de los años 1990. Por un lado, el caso de Jackson Square nos permite comprender el papel de la sociedad civil y el tercer sector en la regeneración de los barrios más desfavorecidos, en un claro ejemplo de urbanismo “desde abajo” (bottom-up planning). Por otro, la reconversión del frente marítimo de South Boston para la construcción del Distrito de Innovación nos acerca a las grandes operaciones de regeneración urbana con fines de estímulo económico, tradicionalmente vinculadas a los centros financieros (downtown) y dirigidas por las élites gubernamentales y económicas (la growth machine) a través de procesos más tecnocráticos (top-down planning). La metodología utilizada consiste en el análisis cualitativo de los procesos de toma de decisiones y la relación entre los agentes implicados, así como de la evaluación de la implementación de dichas decisiones y su influencia en el modelo urbano resultante. El análisis de los casos permite afirmar que la gobernanza de los procesos de regeneración urbana influye decisivamente en el resultado final de las intervenciones; sin embargo, la participación de la comunidad local en la toma de decisiones no es suficiente para que el resultado de la regeneración urbana contrarreste los efectos de la neoliberalización, especialmente si se limita a la fase de planeamiento y no se extiende a la fase de ejecución, y si no está apoyada por una movilización política de mayor alcance que asegure una acción pública redistributiva. Asimismo, puede afirmarse que los procesos de regeneración urbana suponen una redefinición del modelo de ciudad, dado que la elección de los espacios de intervención tiene consecuencias sobre el equilibrio territorial de la ciudad. Los resultados de esta investigación tienen implicaciones para la disciplina del planeamiento urbano. Por una parte, se confirma la vigencia del paradigma del “urbanismo negociado”, si bien bajo discursos de liderazgo público y sin apelación al protagonismo del sector privado. Por otra parte, la planificación colaborativa en un contexto de “responsabilización” de las organizaciones comunitarias puede desactivar la potencia política de la participación ciudadana y servir como “amortiguador” hacia el gobierno local. Asimismo, la sustitución del planeamiento general como instrumento de definición de la ciudad futura por una planificación oportunista basada en la actuación en áreas estratégicas que tiren del resto de la ciudad, no permite definir un modelo coherente y consensuado de la ciudad que se desea colectivamente, ni permite utilizar el planeamiento como mecanismo de redistribución. ABSTRACT In the past three decades, the dynamics of global economic restructuring have radically redefined the role of cities. The transition from keynesianism to neoliberalism has caused a shift in local governments’ urban policies, which have progressively abandoned the tasks of regulation and redistribution to focus on promoting economic growth and competitiveness. In this context, many critics have pointed out that urban regeneration has become a vehicle for extracting value from the city and is causing the expulsion of the most vulnerable citizens. However, regeneration of consolidated areas is also an opportunity to improve the living conditions of the resident population, and is a necessary policy to control the expansion of the city and reduce the need for transportation, thus promoting more sustainable cities. Assuming that the governance of urban regeneration processes is key to the final outcome of the plans and determines the resulting city model, the goal of this research is to verify whether urban regeneration is necessarily a value extraction mechanism or if it can improve the quality of life in cities through citizens’ participation. It proposes a framework for analysis of decision-making in urban regeneration processes and their impact on the results of the plans, taking as a case study the city of Boston, which since the 1990s is trying to become a "city of neighborhoods", encouraging citizen participation, while seeking to position itself in the global economic scene. The analysis focuses on two redevelopment plans initiated in the late 1990s. The Jackson Square case allows us to understand the role of civil society and the third sector in the regeneration of disadvantaged neighborhoods, in a clear example of bottom-up planning. On the contrary, the conversion of the South Boston waterfront to build the Innovation District takes us to the big redevelopment efforts with economic stimulus’ goals, traditionally linked to downtowns and led by government and economic elites (the local “growth machine”) through more technocratic processes (top-down planning). The research is based on a qualitative analysis of the processes of decision making and the relationship between those involved, as well as the evaluation of the implementation of those decisions and their influence on the resulting urban model. The analysis suggests that the governance of urban regeneration processes decisively influences the outcome of interventions; however, community engagement in the decision-making process is not enough for the result of the urban regeneration to counteract the effects of neoliberalization, especially if it is limited to the planning phase and does not extend to the implementation of the projects, and if it is not supported by a broader political mobilization to ensure a redistributive public action. Moreover, urban regeneration processes redefine the urban model, since the choice of intervention areas has important consequences for the territorial balance of the city. The results of this study have implications for the discipline of urban planning. On the one hand, it confirms the validity of the "negotiated planning" paradigm, albeit under public leadership discourse and without a direct appeal to the leadership role of the private sector. On the other hand, collaborative planning in a context of "responsibilization" of community based organizations can deactivate the political power of citizen participation and serve as a "buffer" towards the local government. Furthermore, the replacement of comprehensive planning, as a tool for defining the city's future, by an opportunistic planning based on intervention in strategic areas that are supposed to induce change in the rest of the city, does not allow a coherent and consensual urban model that is collectively desired, nor it allows to use planning as a redistribution mechanism.

Location of bioelectricity plants in the Madrid Community based on triticale crop: a multicriteria methodology

This paper presents a work whose objective is, first, to quantify the potential of the triticale biomass existing in each of the agricultural regions in the Madrid Community through a crop simulation model based on regression techniques and multiple correlation. Second, a methodology for defining which area has the best conditions for the installation of electricity plants from biomass has been described and applied. The study used a methodology based on compromise programming in a discrete multicriteria decision method (MDM) context. To make a ranking, the following criteria were taken into account: biomass potential, electric power infrastructure, road networks, protected spaces, and urban nuclei surfaces. The results indicate that, in the case of the Madrid Community, the Campiña region is the most suitable for setting up plants powered by biomass. A minimum of 17,339.9 tons of triticale will be needed to satisfy the requirements of a 2.2 MW power plant. The minimum range of action for obtaining the biomass necessary in Campiña region would be 6.6 km around the municipality of Algete, based on Geographic Information Systems. The total biomass which could be made available in considering this range in this region would be 18,430.68 t.

Instruments for analysing urban conflicts in the Global South: The case of urban transformation processes in Dakar

Physical and social transformation processes that take place in urban contexts with strong spatial growth and hardly any economic development frequently have significant adverse impacts for the affected people, which tend to be made invisible. This paper presents an analytical framework to explore different ways to approach urban transformation processes (supply side), their impacts on the set of needs of the community (demand side) and their consequences on the urban environment as a whole (context). The proposed method has been used to assess three actions related to the physical and social transformation of the largest self-made settlement in the city of Dakar, Senegal, during the 2005–2012 period. Research findings show how exogenous interests are privileged over the common good when the affected citizens are not effectively involved in decision-making processes.

The anatomy of urban social networks and its implications in the searchability problem

The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure.

Arsenic, antimony and selenium in urban soils: potential risks for human health in urban gardening

The benefits of urban agriculture are many and well documented, ranging from health improvement to community betterment, more sustainable urban development and environment protection. On the negative side, urban soils are commonly enriched in toxic trace elements that have accumulated over time through the deposition of atmospheric particles (generated by automotive traffic, heating systems, historical industrial activities and resuspended street dust), and the uncontrolled disposal of domestic, commercial and industrial wastes. This in turn has given rise to concerns about the level of exposure of urban farmers to these elements and the potential health hazards associated with this exposure. Research efforts in this field have started relatively recently and have almost systematically omitted the influence of Sb and Se, and to a lesser extent of As, although all three have proven toxic effects.