Geotaxis baseline data for Drosophila

Geotaxis profiles for 20 Drosophila species and semispecies at different ages have been examined using a calibrated, adjustable slant board device. Measurements were taken at 5 deg intervals ranging from 0 deg to 85 deg. Clear strain and species differences are observed, with some groups tending to move upward (- geotaxis) with increasing angles, while others move downward (+ geotaxis). Geotactic responses change with age in some, but not all experimental groups. Sample geotaxis profiles are presented and their application to ecological and aging studies are discussed. Data provide a baseline for future evaluations of the biological effects of microgravity

Theory of Luminescent Emission in Nanocrystal ZnS:Mn with an Extra Electron

We consider the effect of an extra electron injected into a doped quantum dot $ZnS:Mn^{2+}$. The Coulomb interaction and the exchange interaction between the extra electron and the states of the Mn ion will mix the wavefunctions, split the impurity energy levels, break the previous selection rules and change the transition probabilities. Using this model of an extra electron in the doped quantum dot, we calculated the energy and the wavefunctions, the luminescence probability and the transition lifetime and compare with the experiments. Our calculation shows that two orders of magnitudes of lifetime shortening can occur in the transition $^4T_1-^6A_1$ when an extra electron is present.Comment: 15 pages, 2 Figs No change in Fig

Numerical Computation of Flow and Heat Transfer from an Enclosed Rotating Disk with Suction and Injection

The Newton Raphson technique has been employed to solve the set of non-linear equations governing the problem of flow and heat transfer from an enclosed rotating disc. /The disc called rotor is subjected to uniform injection while the top of the housing called stator, to an equal suction. The results for small Reynold numbers are found in good agreement to that obtained earlier by series solution. The radial and transverse velocity profiles for large Reynolds have been plotted in the regions of no recirculation. The effect of net radial inflow and outflow on temperature in the no-recirculation region has also been studied. The method is significant in this respect that it yields satisfactory results for large Reynolds numbers