Morphological effects on IR band profiles: Experimental spectroscopic analysis with application to observed spectra of oxygen-rich AGB stars

To trace the source of the unique 13, 19.5, and 28 $\mu$m emission features in the spectra of oxygen-rich circumstellar shells around AGB stars, we have compared dust extinction spectra obtained by aerosol measurements. We have measured the extinction spectra for 19 oxide powder samples of eight different types, such as Ti-compounds (TiO, TiO$_2$, Ti$_2$O$_3$, Ti$_3$O$_5$, Al$_2$TiO$_5$, CaTiO$_3$), $\alpha$-, $\gamma$-, $\chi$-$\delta$-$\kappa$-Al$_2$O$_3$, and MgAl$_2$O$_4$ in the infrared region (10 - 50 $\mu$m) paying special attention to the morphological (size, shape, and agglomeration) effects and the differences in crystal structure. Anatase (TiO$_2$) particles with rounded edges are the possible 13, 19.5 and 28 $\mu$m band carriers as the main contributor in the spectra of AGB stars, and spherically shaped nano-sized spinel and Al$_2$TiO$_5$ dust grains are possibly associated with the anatase, enhancing the prominence of the 13 $\mu$m feature and providing additional features at 28 $\mu$m. The extinction data sets obtained by the aerosol and CsI pellet measurements have been made available for public use at http://elbe.astro.uni-jena.deComment: 17 pages, 8 figures, Accepted 24 March 2009 for publication in A&

Parties and government: Incumbency and representation in parliamentary democracies

In spite of large electoral changes since the 1990s, party composition of government changes less and established parties stay longer in office than others regardless their electoral fortunes. This development is conducive to incongruence between the parties represented in parliament and those in government. It is argued that office-seeking behaviour tends to become more prominent, resulting in dominant (strongest parliamentary party) and central parties show a prolonged incumbency. If dominance and centrality occur simultaneously a pivot party emerges. This type of party is indeed characterized by prolonged incumbency of government that is often considered as political stability. This development is analysed for 16 West European democracies (before and after 1990). I contend that a representative bias has emerged that could signify a change in the representative quality of representative government in Western Europe. Stable government, when based upon less correspondence between party representation in parliament and party representation in government, may have come at a price for overall representative of democracy. © 2011 Macmillan Publishers Ltd