No abstract

105he concept of engagement was developed to explain what traditional studies of work motivation overlookednamely, that employees offer up different degrees and dimensions of themselves according to some internal calculus that they consciously and unconsciously compute (Kahn, 1990). Traditional motivation studies implicitly assumed that workers were either on or off; that is, on the basis of external rewards and intrinsic factors, they were either motivated to work or not, and this was a relatively steady state that they inhabited (e.g., Taylor, 1911;Vroom, 1964). The engagement concept is framed on the premise that workers are more complicated than this. Like actors, they make choices about how much of their real selves they would bring into and use to inform their role performances (Kahn, 1990). They might truly express themselves, to the extent the role allows, or they might not, with varying degrees of expression in between. Rather than label workers as motivated or not, these personal movements

The redox budget during subduction is tied to the evolution of oxygen and biogeochemical cycles on Earth's surface over time. The sulphide-sulphate couple in subducted crust has significant potential for redox and control on extraction of chalcophile metals from the arc mantle. We derive oxygen buffers for sulphide-sulphate stability ('SSO buffers') using mineral assemblages in subducted crust within the eclogite facies, and examine their disposition relative to the fO 2 in the arc mantle along various P-T trajectories for subduction. The fO 2 required for sulfide stability in subducted crust passing beneath an arc is shifted by variations in the bulk Ca/(Ca+Mg+Fe) of the subducting crust alone. Hotter slabs and more Fe-rich sediments stabilize sulphide and favour chalcophile sequestration deep into the mantle, whereas colder slabs and calcic sediment will stabilize anhydrite, in some cases at depths of melt generation in the arc mantle (< 130 km). The released sulfate on melting potentially increases the fO 2 of the arc mantle. We performed melting experiments on three subducted sediment compositions varying in bulk Ca/(Ca+Mg+Fe) from 0.3 to 0.6 at 2.5 GPa and 900-1100°C to confirm how anhydrite stability can change by orders of magnitude the S, Cu, As, Zn, Mo, Pb, and Sb contents of sediment melts, and their subsequent liberation to the arc mantle. Using Cu/Sc as a proxy for the behavior of S, the effect of variable

ZusammenfassungDie gewonnen geologischen, geomorphologischen und geotechnischen Grundlagenerkenntnisse an der im Kristallin weltweit gewaltigsten und einzigartigen Großmassenbewegung des Tsergo Ri im Langthangtal des zentralen Nepal Himalaya entschlüsselten nicht nur den chronologischen Ablauf der Paläo-Ereignisse vor Ort, sondern können auch direkt auf eine Einstufung des rezenten Gefahrenpotentials dieser Gegend und ähnlich geotektonisch-lithologisch positionierter Bereiche des Himalaya und der Erde angewendet werden. Dies konnte vorerst am Beispiel weiterer, kleinerer Bergstürze im Langthangtal selbst, im Kristallin des Annapurna Massivs und mit einem Vergleich zu einer Felslawine in Zentralchina bestätigt werden.