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

Correlated growth of organic material tris (8-hydroxyquinoline) aluminum (Alq3) and its relation to optical properties

We report slow correlated growth mode in energetic cluster vapor deposited organic light emissive material tris(8-hydroxyquinoline) aluminum from 5 to 100 nm. Phase modulated atomic force microscopy shows very slow grain growth with thickness, with very small phase differences within the film.Fractal dimension calculated from correlation function shows growth process above 10 nm consistent with diffusion-limited aggregation. For low thickness (5 nm), photoluminescence measurement shows the emission peak is shifted by ∼0.4 eV toward lower wavelength