Institute for Transuranium Elements Activity Report 2002.

Abstract not availableJRC.E-Institute for Transuranium Elements (Karlsruhe

The Milky Way halo as a QSO absorption-line system. New results from an HST/STIS absorption-line catalogue of Galactic high-velocity clouds

We use archival UV absorption-line data from HST/STIS to statistically analyse the absorption characteristics of the high-velocity clouds (HVCs) in the Galactic halo towards more than 40 extragalactic background sources. We determine absorption covering fractions of low- and intermediate ions (OI, CII, SiIII, MgII, FeII, SiIII, CIV, and SiIV) in the range fc = 0.20 - 0.70. For detailed analysis we concentrate on SiII absorption components in HVCs, for which we investigate the distribution of column densities, b-values, and radial velocities. Combining information for SiII and MgII, and using a geometrical HVC model we investigate the contribution of HVCs to the absorption cross section of strong MgII absorbers in the local Universe. We estimate that the Galactic HVCs would contribute on average ~52 % to the total strong MgII cross section of the Milky Way, if our Galaxy were to be observed from an exterior vantage point. We further estimate that the mean projected covering fraction of strong MgII absorption in the Milky Way halo and disc from an exterior vantage point is fc(sMgII) = 0.31 for a halo radius of R = 61 kpc. These numbers, together with the observed number density of strong MgII absorbers at low redshift, indicate that the contribution of infalling gas clouds (i.e., HVC analogues) in the halos of Milky Way-type galaxies to the cross section of strong MgII absorbers is <34 %. These findings are in line with the idea that outflowing gas (e.g., produced by galactic winds) in the halos of more actively star-forming galaxies dominate the absorption-cross section of strong MgII absorbers in the local Universe

Synthesis and characterization of biodegradable lignin nanoparticles with tunable surface properties

Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and Organosolv (high-purity lignin). The green synthesis process is based on flash precipitation of dissolved lignin polymer, which enabled the formation of nanoparticles in the size range of 45–250 nm. The size evolution of the two types of lignin particles is fitted on the basis of modified diffusive growth kinetics and mass balance dependencies. The surface properties of the nanoparticles are fine-tuned by coating them with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride). We analyze how the colloidal stability and dispersion properties of these two types of nanoparticles vary as a function of pH and salinities. The data show that the properties of the nanoparticles are governed by the type of lignin used and the presence of polyelectrolyte surface coating. The coating allows the control of the nanoparticles’ surface charge and the extension of their stability into strongly basic regimes, facilitating their potential application at extreme pH conditions

Do sojourn effects on personality trait changes last? A five-year longitudinal study

Richter J, Zimmermann J, Neyer FJ, Kandler C. Do sojourn effects on personality trait changes last? A five-year longitudinal study. European Journal of Personality. 2020;35(3):358-382.This study examined sojourners’ long-term personality trait changes over five years, extending previous research on immediate sojourn effects. A sample of German students (N = 1,095) was surveyed thrice (T1-T3) over the course of an academic year. Sojourners (n = 498) lived abroad shortly after T1 for one or two semesters, stayers (n = 597) remained in their home country. Five years after T1, we surveyed the same participants (n = 441, 40.3%) again (T4). Beyond substantial selection effects, latent neighbor-change models revealed that small differences between sojourners’ and stayers’ openness, agreeableness, and neuroticism changes occurred early after sojourn-induced contextual change. Model estimates suggested sustained sojourn effects on openness and neuroticism changes thereafter, and a reversed effect on agreeableness change after return. Due to reduced power and low accuracy at T4, these estimates were not statistically significant. Based on model comparison analyses, however, we could rule out reversed effects for openness and accentuated effects for agreeableness and neuroticism as least likely. Moreover, separating short-term and long-term sojourners revealed no substantial differences, but recurring sojourn experiences tended to play a role in sustaining differences. We discuss implications for future studies on patterns of sojourn effects on personality trait changes