Search results for "wt"
showing 10 items of 5424 documents
La atención a la situación del mundo en la educación científica
2021
Protagonizamos en la actualidad una epoca de profundas y aceleradas transformaciones que, unida a una multiplicidad de problemas medioambientales y sociales cuyos efectos vienen agravandose a nivel planetario, ha convertido la "situacion del mundo" en objeto directo de preocupacion. En la Conferencia de las Naciones Unidas sobre Medio Ambiente y Desarrollo, celebrada en Rio de Janeiro en 1992 y conocida como Primera Cumbre de la Tierra, se reclamo una decidida accion de los educadores, de todas las areas, para que los ciudadanos y ciudadanas adquieran una correcta percepcion de cual es esa situacion y puedan participar en la toma de decisiones fundamentadas. Un primer proposito de esta inve…
Organization and expression of the chum salmon insulin-like growth factor II gene
1997
AbstractIGF-II plays an important role in growth and development of vertebrates. In the present study, the characterization of the first fish IGF-II gene, chum salmon IGF-II, is described. The sIGF-II gene consists of four exons, spanning a region of 9 kbp, that encode the 214 aa IGF-II precursor. While the amino acid sequences of fully processed IGF-II of salmon and mammalian species are very similar, the prepro-peptide sequence deviates extensively in the signal- and E-peptide domains. The transcription initiation site of the sIGF-II gene was localized within a 30 nt region employing RT-PCR. Using sIGF-II promoter-luciferase constructs it was demonstrated that the sIGF-II gene has a relat…
Assessment of Energy and Economic Effectiveness of Photovoltaic Systems Operating in a Dense Urban Context
2013
A methodology that permits testing the level of integration of the photovoltaic technology in urban areas is presented. The percentage of coverage of the electricity demand of grid-connected photovoltaic systems installed on the roofs of buildings were investigated in a district of the city of Palermo (Sicily). After classifying roofs according to their shape, orientation and pitch by means of satellite images provided by Google Earth, the ratio of the productivity of the PV systems and the consumption of electricity of the households was analysed. The results of the energy assessment have been screened considering the economic feasibility of grid-connected photovoltaic systems: the energy …
Externalités d'informations et évolution des villes
1999
Present-day city growth is chiefly the result of new tertiary activities such as financial and producer services, R&D, or business administration. These activities consume human capital, knowledge and high-tech capital, which are all rapidly changing inputs; they are based on complex decision-making processes; this renders them highly information-dependent. Inasmuch as these activities are the main key to understanding the city, information must play a leading role in understanding urban forms. The concentration of these activities in cities appears paradoxical in the era of information. They are agglomerated because of their need of proximity for exchanging information. But information can…
Effects of undergrowth removal and edge proximity on ground beetles and vascular plants in urban boreal forests
2019
From a Barrio Chino Urban Stigma to the Raval Cultural Brand: Urban Memory and Cultural Policies in the Renewal of Central Barcelona
2020
Barcelona, and especially, its historic center, has undergone a profound transformation from an industrial city to a global tourism and services center. Some authors insist on the destructive nature of the urban regeneration of the historic Barcelona district of Raval as a process of de-identification of the city center or as an intentional falsification of its identity to turn it into a tourist space. However, as we discuss in this article, urban branding and urban change projects should address not only the infrastructural issues of transformation, but also the development of new urban branding based on recreating a memory of the place. Thus, in the case of Raval, the urban and cultural …
Subversion of land-use plans and the housing bubble in Spain
2011
The exceptional rhythm of the construction of residential dwellings in Spain between 1997 and 2006 and its geographical contrasts are explained by a time of economic expansion, a political and social context favourable to unlimited growth and excessive and untempered municipal land-use plans with passive or complicit regional governments. The lack of effective land-use regional plans and the discrediting of municipal land-use plans are a manifestation of a deliberate subversion of public planning to subordinate the public interest to the developer's demands. This article concludes by presenting a panorama of the disturbing consequences of this urban development model.
On the emergence of the urban phenomenon. Part I
2001
In this paper we develop a relatively simple but general model describing the formation of urban agglomerations in a pre-industrial setting. Rural agglomeration on a local scale arises from the multiplication and specialization of intermediate goods and labor services, while dispersion is due to the commuting costs of agricultural workers. Urban agglomeration on a more global scale stems from the trade-off between increasing returns to scale and transport costs of goods. We derive a general equilibrium model of the formation of urban structures and show how population growth, strict indivisibilities and structural changes in the production sector can modify quantitatively and qualitatively …
Housing Affordability in Metropolitan Areas. The Application of a Combination of the Ratio Income and Residual Income Approaches to Two Case Studies …
2017
Housing affordability problems have become more serious over the course of the last few decades and are now also affecting the middle-class, despite the fall in prices on the housing market. This study proposes a methodology to assess threshold-income as an index for measuring housing affordability by applying a combination of the ratio income and residual income approaches. The methodology is applied to two particular areas of Sicily in Italy as case studies consisting of medium-size metropolitan areas located in a less developed European region. The areas have been chosen on the basis of their different territorial structure: a polarized area that comprises a high-density city centre and …
Giustizia ambientale e recupero delle aree verdi: il caso di Palermo
2021
L’urban shrinkage è diventata una questione centrale tanto nel dibattito scientifico quanto nell’agenda politica di diverse città europee. Secondo i dati EUROSTAT (2019), circa il 40% delle città europee con più di 200.000 abitanti stanno perdendo popolazione; una contrazione che si esplicita maggiormente, sotto il profilo spaziale, in una progressiva sottoutilizzazione del patrimonio edificato, così come nel contestuale incremento di aree e terreni in stato di abbandono. In questo quadro controverso di mutazione strutturale della città, così come l’abbiamo conosciuta, le politiche urbane alla prova in Europa tentano di declinare la decrescita quale occasione strategica di investimento sull…