We correlate the X-ray luminosity and the X-ray hardness of the central object with the crystalline mass fraction of the circumstellar dust and find a significant anti-correlation for 20 objects within an age range of approx. Since the sample includes objects with disks of various evolutionary stages, we further confine the target selection, using the age of the objects as a selection parameter.

The dust crystallinity is measured for 42 class II T Tauri stars in the Taurus star-forming region using a decomposition fit of the 10 micron silicate feature, measured with the Spitzer IRS instrument. In this paper, we present a study on the possible influence of the stellar irradiation, indicated by X-ray emission, on the crystalline structure of the circumstellar dust. High-energy irradiation of the circumstellar material might impact the structure and the composition of a protoplanetary disk and hence the process of planet formation. Turning to the Spanish economy, the low level of energy RD&D, the limited openness to trade resulting from an economic structure strongly based on the Tourism and the Construction sector, the small average size of the industrial companies and the low energy prices explain an important part of the poor performance of energy efficiency after 1992. This paper finds evidence of a significant impact of the next variables on energy efficiency: Energy prices, Energy research, development and demonstration, Openness to trade of the country, Average firm size and Initial level of energy efficiency in the country. The second block explores the underlying causes that have driven the evolution of energy intensity across the OECD economies and further analyses the evolution of those variables affecting energy efficiency in the Spanish economy. This analysis shows two clearly marked trends on the evolution of energy efficiency in the Spanish economy: a strong increase at a faster pace than the OECD average during the subperiod 1980-1995 and a rapid decline during the subperiod 1995-2005. This paper consists of two main blocks: the first analyzes the evolution of energy intensity (or energy efficiency) across a broad group of OECD countries for the period 1980-2005 with a high level of sectoral resolution, focusing the analysis on the Spanish economy.

High resolution smith chart pdf