La incidencia de la calificación energética sobre los valores residenciales: un análisis para el mercado plurifamiliar en Barcelona
RESUMENEste artículo estudia de forma pionera en España la incidencia de la calificación energética sobre los valores residenciales. Para ello se analizan, mediante un modelo hedónico, datos de precios de venta de la Barcelona metropolitana. Los resultados sugieren que pasar de una calificación G a una A incrementa el valor en un 5,11 %, equivalente de media a 16,07 euros/m 2 /escalón (aunque existe un extra para las viviendas A). Este sobrevalor es, en términos relativos, muy inferior al de otras ciudades europeas y, en términos absolutos, menor que los sobrecostes relativos una mejora en la calificación energética reportados previamente. Además, la enorme ausencia de información energética en la comercialización parece responder a una estrategia para ocultar la pobre calificación del parque edificado y agravar la asimetría informativa. Todo junto ensombrece la eficacia de la Directiva Europea de Eficiencia Energética tal como ha sido transpuesta en nuestro país, y clama por su rediseño.
RESUMENLas ciudades además de ser centros de interacción social y económica, tienen unos atributos urbanos y arquitectónicos inherentes que las hacen atractivas para la concentración de personas y actividades económicas diversas. En este artículo se estudia para la Región Metropolitana de Barcelona cómo la proximidad física a los centros urbanos de mayor jerarquía constituye un elemento determinante para el crecimiento del empleo en los sectores económicos intensivos en conocimiento. Se estudian por ello los factores que están explicando la densidad y los cambios en la concentración del empleo en el periodo 1991-2001 en las áreas de funcionalidad económica de la Región. Los resultados muestran que es fundamentalmente la distancia al centro metropolitano el factor determinante del crecimiento de estos sectores económicos por los beneficios que la aglomeración y la proximidad geográfica tienen para su desempeño.Palabras clave: economía del conocimiento, centralidad urbana, proximidad geográfica.
ABSTRACTCities have some inherent urban and architectural attributes that make them attractive to the concentration of people and various economic activities. This article analyses how physical proximity to main urban centres of the Metropolitan Region of Barcelona is a determining factor for the growth of employment in the intensive economic activities based on knowledge. For this purpose we study the factors that explain employment density and changes in the concentration of employment during the period 1991-2001 on the functional economic areas of the Region. Results show that it is basically the distance to the metropolitan core the capital factor to the growth of the knowledge economy, due to the benefits that agglomeration and physical proximity have for its development.
<p><strong>Abstract.</strong> Diatoms tend to dominate the Arctic spring bloom, a key event in the ecosystem. Large sinking of diatoms is expected at the end of the bloom driven by deteriorated cell status associated to nutrients (silicon) depletion. However, there are few reports on the status of diatoms' health during Arctic blooms and its possible role on sedimentary fluxes. Here we quantify, using the Bottle-Net, Arctic diatom stocks below and above the photic layer and assess their cell health status. The communities were sampled around the Svalbard Islands and encompassed a broad diversity of conditions and bloom stages. About 1/4 (mean&#177;SE 24.2 &#177; 6.7&#8201;%) of the total water column (max. 415&#8201;m) diatom stock was found below the photic layer, indicating significant sinking of diatoms in the area. The fraction of living diatom cells in the photic layer averaged 59.4 &#177; 6.3&#8201;% but showed the highest percentages (72.0&#8201;%) in stations supporting active blooms. In contrast, populations below the photic layer were dominated by dead cells (20.8 &#177; 4.9&#8201;% living cells). The percentage of diatom&#8217;s stock found below the photic layer was negatively related to the percentage of living diatoms in the surface, indicating that healthy populations remained in the surface layer. An experiment on board in a tall (1.35&#8201;m) sedimentation column confirmed that dead diatom cells from the Arctic community sink faster that living ones. Also, diatoms cell mortality increased in darkness, showing an averaged half life of 1.025 &#177; 0.075&#8201;d<sup>&#8722;1</sup>. The results conform to a conceptual model where diatoms grow during the bloom until silicic acid stocks are depleted, and support a link between diatom cell health status and sedimentation fluxes in the Arctic. Healthy arctic phytoplankton communities remained at the photic layer, whereas dying communities exported a large fraction of the biomass to the aphotic zone, fuelling carbon sequestration and benthic ecosystems.</p>
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