Aggregation and aging in silica gel

Aggregation and aging of silica gels, prepared by controlled addition of water glass to hydrochloric acid, and the transformation of an aged gel to a crystalline phase have been studied in-situ using high-brilliance synchrotron radiation. Small angle X-ray scattering (SAXS) has proved to be very informative in readily detecting transformations in the silica gels which can be described using the concepts of mass and surface fractality. The interpretation of SAXS spectra of aged silica gels has been accompanied by computer simulations of aggregation and aging based on a model for the aging mechanism and the calculation of the corresponding structure-factor patterns. Comparison with experimental spectra of aged silica highlights the important role of particle growth on the fractal dimension. Gel transformations during the transition from an amorphous gel to the crystalline phase of silicalite have been successfully monitored, in-situ, both for heterogeneous and for homogeneous preparations, using the combination of small and wide angle X-ray scattering (SAXS-WAXS

Peri-articular histiocytic sarcoma in Bernese Mountain Dogs : a retrospective investigation of the prevalence of this tumour in association with previously diseases joints

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Systematic investigation of the elastic proton-deuteron differential cross section at intermediate energies

To investigate the importance of three-nucleon forces (3NF) systematically over a broad range of intermediate energies, the differential cross sections of elastic proton-deuteron scattering have been measured at proton bombarding energies of 108, 120, 135, 150, 170 and 190 MeV at center-of-mass angles between $30^\circ$ and $170^\circ$. Comparisons with Faddeev calculations show unambiguously the shortcomings of calculations employing only two-body forces and the necessity of including 3NF. They also show the limitations of the latest few-nucleon calculations at backward angles, especially at higher beam energies. Some of these discrepancies could be partially due to relativistic effects. Data at lowest energy are also compared with a recent calculation based on \chipt

Proton-deuteron radiative capture cross sections at intermediate energies

Differential cross sections of the reaction $p(d,^3{\rm He})\gamma$ have been measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were obtained with a coincidence setup measuring both the outgoing $^3$He and the photon. The data are compared with modern calculations including all possible meson-exchange currents and two- and three- nucleon forces in the potential. The data clearly show a preference for one of the models, although the shape of the angular distribution cannot be reproduced by any of the presented models.Comment: 6 pages, 6 figures, accepted for publication in EPJ

Wages in high-tech start-ups - do academic spin-offs pay a wage premium?

Due to their origin from universities, academic spin‐offs operate at the forefront of the technological development. Therefore, spin‐offs exhibit a skill‐biased labour demand, i.e. spin‐offs have a high demand for employees with cutting edge knowledge and technical skills. In order to accommodate this demand, spin‐offs may have to pay a relative wage premium compared to other high‐tech start‐ups. However, neither a comprehensive theoretical assessment nor the empirical literature on wages in start‐ups unambiguously predicts the existence and the direction of wage differentials between spin‐offs and non‐spin‐offs. This paper addresses this research gap and examines empirically whether or not spin‐offs pay their employees a wage premium. Using a unique linked employer‐employee data set of German high‐tech start‐ups, we estimate Mincer‐type wage regressions applying the Hausman‐Taylor panel estimator. Our results show that spin‐offs do not pay a wage premium in general. However, a notable exception from this general result is that spin‐offs that commercialise new scientific results or methods provide higher wages to employees with linkages to the university sector – either as university graduates or as student workers