The STACEE-32 Ground Based Gamma-ray Detector

We describe the design and performance of the Solar Tower Atmospheric Cherenkov Effect Experiment detector in its initial configuration (STACEE-32). STACEE is a new ground-based gamma ray detector using the atmospheric Cherenkov technique. In STACEE, the heliostats of a solar energy research array are used to collect and focus the Cherenkov photons produced in gamma-ray induced air showers. The large Cherenkov photon collection area of STACEE results in a gamma-ray energy threshold below that of previous detectors.Comment: 45 pages, 25 figures, Accepted for publication in Nuclear Instruments and Methods

Quantitative importance of staminodes for female reproductive success in Parnassia palustris under contrasting environmental conditions.

The five sterile stamens, or staminodes, in Parnassia palustris act both as false and as true nectaries. They attract pollinators with their conspicuous, but non-rewarding tips, and also produce nectar at the base. We removed staminodes experimentally and compared pollinator visitation rate and duration and seed set in flowers with and without staminodes in two different populations. We also examined the relative importance of the staminode size to other plant traits. Finally, we bagged, emasculated, and supplementary cross-pollinated flowers to determine the pollination strategy and whether reproduction was limited by pollen availability. Flowers in both populations were highly dependent on pollinator visitation for maximum seed set. In one population pollinators primarily cross-pollinated flowers, whereas in the other the pollinators facilitated self-pollination. The staminodes caused increased pollinator visitation rate and duration to flowers in both populations. The staminodes increased female reproductive success, but only when pollen availability constrained female reproduction. Simple linear regression indicated a strong selection on staminode size, multiple regression suggested that selection on staminode size was mainly caused by correlation with other traits that affected female fitness. [ABSTRACT FROM AUTHOR

Learned liking versus inborn delight. Can sweetness give sensual pleasure or is it just motivating?

In this study, we separated for the first time the learned liking for a particular level of sweetness in a familiar drink from the infantile delight in sweetness as such (“the sweeter, the better”). It is widely assumed that sensing a liked food or drink evokes a pleasurable experience, but the only psychological evidence for this assumption has been tongue movements that are elicited specifically by sweet taste in animals and human neonates. We found that adults felt such movements in response to drinking juice at both their personally preferred level of sweetness and levels they deemed so sweet as to be undrinkable. Yet only the intolerably strong level of sweetness elicited enjoyment of the experienced movements, elevation of mood, and a sense of smiling. Hence, the pleasure that adults experience during ingestion could be exclusively linked with the congenital sweetness reflex that sends mother’s milk down an infant’s throat