Uncertainty, learning and growth

The paper extends Blackburn and Galindev's (Economics Letters, Vol. 79 (2003), pp. 417-421) stochastic growth model in which productivity growth entails both external and internal learning behaviour with a constant relative risk aversion utility function and productivity shocks. Consequently, the relationship between long-term growth and short-term volatility depends not only on the relative importance of each learning mechanism but also on a parameter measuring individuals' attitude towards risk.

Chase over the Nile: The Social Evolution of Riverine Landscape in Urban Egypt

Throughout its history, Cairo evolved as a regional metropolis that sprawls along the banks of the Nile accumulating narratives of evolving social landscape. Overlooking the Nile reflected a privileged social position and place for the urban elite. In spatial terms, the urban bourgeoisie tend to develop living havens in enclaves that are distant from the populace’s everyday life. Ironically, exclusive settlements only attract urban growth further in their direction. This chapter offers an analytical reading of the socio-spatial structure of Cairo following the emergence and decline of a series bourgeoisie quarters along the shores of the Nile. It reports urban narratives based on archival records, documents and investigation of historical texts and travelers’ accounts. This essay argues that cities are essentially social constructs in which hierarchy and connectivity are fundamental aspects of its economic and spatial logic. Through social ambition and desire for upgrade, middle class infiltrate into bourgeoisie havens and sometimes encircle it, seeking better living condition inscribed by social mobility and connectivity to centres of wealth and power. Being both natural barrier and cohesive spine, the Nile helped Cairo to develop successive nucleuses of highly crafted urban experiences that have left their imprints on the contemporary urban scene.

A Sensitivity Analysis of Cross-Country Growth Regressions: Is 1990-2010 Different?

Cet article étudie la sensibilité des estimations de certaines variables explicatives de la croissance économique dans des régressions en coupe transversale sur un ensemble de pays. Il applique un modèle modifié de l’analyse de sensibilité de Leamer (1983, 1985). Mes résultats confirment la conclusion de Levine and Renelt (1992), toutefois, je montre que plus de variables sont solidement corrélées à la croissance économique. Entre 1990-2010, je trouve que huit sur vingt cinq variables ont des coefficients significatifs et sont solidement corrélées à la croissance de long terme, notamment, les parts de l’investissement et des dépenses étatiques dans le PIB, la primauté du droit et une variable dichotomique pour les pays subsahariens. Je trouve aussi une preuve empirique solide de l'hypothèse de la convergence conditionnelle, ce qui est cohérent avec le modèle de croissance néoclassique.

Finding Spaces for Urban Food Production – Matching Spatial and Stakeholder Analysis with Urban Agriculture Approaches in the Urban Renewal Area of Dortmund-Hörde, Germany

Using the case of an economically declined neighbourhood in the post-industrial German Ruhr Area (sometimes characterized as Germany’s “Rust Belt”), we analyse, describe and conclude how urban agriculture can be used as a catalyst to stimulate and support urban renewal and regeneration, especially from a socio-cultural perspective. Using the methodological framework of participatory action research, and linking bottom-up and top-down planning approaches, a project path was developed to include the population affected and foster individual responsibility for their district, as well as to strengthen inhabitants and stakeholder groups in a permanent collective stewardship for the individual forms of urban agriculture developed and implemented. On a more abstract level, the research carried out can be characterized as a form of action research with an intended transgression of the boundaries between research, planning, design, and implementation. We conclude that by synchronously combining those four domains with intense feedback loops, synergies for the academic knowledge on the potential performance of urban agriculture in terms of sustainable development, as well as the benefits for the case-study area and the interests of individual urban gardeners can be achieved.

Advances and limitations in the attention to the problems of housing and urban land in Mexico. An approach from the legal-institutional frame

In this work we analyze the reforms carried out by the Mexican state in the nineties of the 20th century, in the items concerning the policies of housing and urban land, based on an exhaustive review of the main actions, programs and changes in the legal and institutional frame that applies for each of these fields. The nineties represent a "breaking point" in the way the State considers the satisfaction of the right to the housing and attends the offer of urbanized land for a tidy and sustainable urban development. In this period of time, the approach of direct intervention in developing and financing housing and creation of land reserves has changed into another one, ruled by the logic of the market. The balance to the first decade of the 21st century is ambiguous, as neither the housing policy has solved the housing shortage for low-income population, nor the land policy has eliminated the illegal urban growth.

Informal access to urban land. Housing policies devoted to vulnerable sectors implemented in Cordoba-Argentina

The urban growth in Latino American cities, in a neoliberal context, has led to several population groups to having no possibilities to the access to urban land. Informal and irregular urban settlements increase, requiring attention from local governments, with actions and strategies in order to achieve both the regularization of such situation and further prevention. In the city of Córdoba different informal and irregular operations have taken place promoted by different actors. Furthermore, policies focused on regularization which have been promoted, have few intervention mechanisms, a fact that becomes critical, especially for the urban problems it causes. The main aim of this article is to present a classification over different modes of urban land acquirement taking place out of both urban and civil legislations. Afterwards, different informal settlement typologies are described, as well as the policies focused on them, together with their respective effects and impacts.

La construcción de equipamientos híbridos en altura como respuesta a un modelo de ciudad denso y compacto: una propuesta para la UPZ N°71 Tibabuyes en la localidad de Suba en Bogotá.

El interés de este trabajo de grado consiste en proponer la construcción de un equipamiento híbrido en altura como alternativa de solución frente al crecimiento poblacional y la escasez de suelo presentes en la Unidad de Planeamiento Zonal- 71 Tibabuyes en la localidad de Suba. Se planea esta propuesta en el marco de un modelo de ocupación territorial denso y compacto contemplado en el Plan de Ordenamiento Territorial de Bogotá. Por tanto, el equipamiento híbrido en altura busca disminuir el déficit y mejorar el acceso a los equipamientos urbanos colectivos por parte de los habitantes de este territorio con el propósito de replantearse la manera de concebir las edificaciones tradicionales que brindan los servicios sociales.

La Costa Brava ante los nuevos retos del turismo

The first section of this paper summarises the most relevant charateristics of the contemporary tourist model, also called postfordist or postmodernist. In the second part the traditional tourist model developed in the Costa Brava in the past decades, is reviewed. Emphasising the saturation of tourist facilities on the coast line, expansive urban growth, thanks to a tolerant administration, poor complementary supply and concentrated demand in few markets and the proximity of Barcelona conurbation, stressed by second homes. In the third section, some strategies developed in recent years to readapt the Costa Brava to the new tendencies in tourism, are presented. Incorporation of the inland to the tourist product, new planning policics, lessening urban densities and height, and a change in mind in favour of protected natural areas, diversification of demand with new markets, specially form Eastern Europe (although this might be considered as a continuation of the traditional tourist model) and the emergence of local strategies oriented towards the creation of new tourist products based upon natural and cultural resources

Paisatge i models urbans contemporanis. Les comarques gironines (1979-2006): del "desarrollismo" a la globalització

This doctoral thesis offers a quantitative and qualitative analysis of the changes in the urban shape and landscape of the Girona Counties between 1979 and 2006. The theoretical part of the research lies within the framework of the dispersed city phenomenon, and is based on the hypothesis of convergence towards a global urban model. The empirical part demonstrates this proposition with a study of 522 zone development plans in the Girona Counties. The results point to the consolidation of the dispersed city phenomenon, as shown by the sudden increase in built-up space, the spread of urban development throughout the territory, and the emergence of a new, increasingly generic landscape comprising three major morphological types: urban extensions, low density residential estates and industrial zones. This reveals shortcomings of planning for urban growth, weakening of the city as a public project, and a certain degradation of the Mediterranean city model.

Evaluating the role of environmental quality in the sustainable rural economic development of England

The issue of the sustainable development of rural economies in England has recently received considerable attention. This is because many of the poorest areas in the country are rural, often of high environmental quality, but suffering from high unemployment and a lack of services and facilities. The rapid decline in agricultural incomes and in-migration of affluent urban workers since 1990 has exacerbated economic inequality in such areas. A number of factors have the potential to drive rural development and this paper applies, and considers, the feasibility of a method from the USA for combining economic and environmental variables in a regional growth model to examine the hypothesis that environmental quality is an important determinant of sustainable rural development in England. The model output suggests that, although environmental quality does play a role in sustainable rural development in England there are other, more important, factors driving development. These include business and communications infra-structure, the degree and opportunities for commuting and underlying employment prospects. The robustness and limitations of the method for combining economic and environmental variables is discussed in relation to the spatial interrelatedness of Local Authority Districts in England, and conclusions are drawn about areas for refinement and improvement of the method.

Modelling the uptake and growth kinetics of Penicillium glabrum in a tannic acid-containing solid-state fermentation for tannase production

A mathematical growth model for the batch solid-state fermentation process for fungal tannase production was developed and tested experimentally. The unstructured model describes the uptake and growth kinetics of Penicillium glabrum in an impregnated polyurethane foam substrate system. In general, good agreement between the experimental data and model simulations was obtained. Biomass, tannase and spore production are described by logistic kinetics with a time delay between biomass production and tannase and spore formation. Possible induction mechanisms for the latter are proposed. Hydrolysis of tannic acid, the main carbon source in the substrate system, is reasonably well described with Michaelis-Menten kinetics with time-varying enzyme concentration but a more complex reaction mechanism is suspected. The metabolism of gallic acid, a tannase-hydrolysis product of tannic acid, was shown to be growth limiting during the main growth phase. (c) 2004 Elsevier Ltd. All rights reserved.

Sea-breeze modification of the growth of a marine internal boundary layer

A numerical mesoscale model is used to make a high-resolution simulation of the marine boundary layer in the Persian Gulf, during conditions of offshore flow from Saudi Arabia. A marine internal boundary layer (MIBL) and a sea-breeze circulation (SBC) are found to co-exist. The sea breeze develops in the mid-afternoon, at which time its front is displaced several tens of kilometres offshore. Between the coast and the sea-breeze system, the MIBL that occurs is consistent with a picture described in the existing literature. However, the MIBL is perturbed by the SBC, the boundary layer deepening significantly seaward of the sea-breeze front. Our analysis suggests that this strong, localized deepening is not a direct consequence of frontal uplift, but rather that the immediate cause is the retardation of the prevailing, low-level offshore wind by the SBC. The simulated boundary-layer development can be accounted for by using a simple 1D Lagrangian model of growth driven by the surface heat flux. This model is obtained as a straightforward modification of an established MIBL analytic growth model.

High resolution simulation of the variability of surface energy balance fluxes across central London with urban zones for energy partitioning

The parameterization of surface heat-flux variability in urban areas relies on adequate representation of surface characteristics. Given the horizontal resolutions (e.g. ≈0.1–1km) currently used in numerical weather prediction (NWP) models, properties of the urban surface (e.g. vegetated/built surfaces, street-canyon geometries) often have large spatial variability. Here, a new approach based on Urban Zones to characterize Energy partitioning (UZE) is tested within a NWP model (Weather Research and Forecasting model;WRF v3.2.1) for Greater London. The urban land-surface scheme is the Noah/Single-Layer Urban Canopy Model (SLUCM). Detailed surface information (horizontal resolution 1 km)in central London shows that the UZE offers better characterization of surface properties and their variability compared to default WRF-SLUCM input parameters. In situ observations of the surface energy fluxes and near-surface meteorological variables are used to select the radiation and turbulence parameterization schemes and to evaluate the land-surface scheme

Research priorities in observing and modeling urban weather and climate

In 2007, the world reached the unprecedented milestone of half of its people living in cities, and that proportion is projected to be 60% in 2030. The combined effect of global climate change and rapid urban growth, accompanied by economic and industrial development, will likely make city residents more vulnerable to a number of urban environmental problems, including extreme weather and climate conditions, sea-level rise, poor public health and air quality, atmospheric transport of accidental or intentional releases of toxic material, and limited water resources. One fundamental aspect of predicting the future risks and defining mitigation strategies is to understand the weather and regional climate affected by cities. For this reason, dozens of researchers from many disciplines and nations attended the Urban Weather and Climate Workshop.1 Twenty-five students from Chinese universities and institutes also took part. The presentations by the workshop's participants span a wide range of topics, from the interaction between the urban climate and energy consumption in climate-change environments to the impact of urban areas on storms and local circulations, and from the impact of urbanization on the hydrological cycle to air quality and weather prediction.

The integrated WRF/urban modelling system: development, evaluation, and applications to urban environmental problems

To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National Center for Atmospheric Research, in collaboration with other agencies and research groups, has developed an integrated urban modelling system coupled to the weather research and forecasting (WRF) model as a community tool to address urban environmental issues. The core of this WRF/urban modelling system consists of the following: (1) three methods with different degrees of freedom to parameterize urban surface processes, ranging from a simple bulk parameterization to a sophisticated multi-layer urban canopy model with an indoor–outdoor exchange sub-model that directly interacts with the atmospheric boundary layer, (2) coupling to fine-scale computational fluid dynamic Reynolds-averaged Navier–Stokes and Large-Eddy simulation models for transport and dispersion (T&D) applications, (3) procedures to incorporate high-resolution urban land use, building morphology, and anthropogenic heating data using the National Urban Database and Access Portal Tool (NUDAPT), and (4) an urbanized high-resolution land data assimilation system. This paper provides an overview of this modelling system; addresses the daunting challenges of initializing the coupled WRF/urban model and of specifying the potentially vast number of parameters required to execute the WRF/urban model; explores the model sensitivity to these urban parameters; and evaluates the ability of WRF/urban to capture urban heat islands, complex boundary-layer structures aloft, and urban plume T&D for several major metropolitan regions. Recent applications of this modelling system illustrate its promising utility, as a regional climate-modelling tool, to investigate impacts of future urbanization on regional meteorological conditions and on air quality under future climate change scenarios. Copyright © 2010 Royal Meteorological Society