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

An anti-social personality for an anti-social habit? The relationship between multi-dimensional schizotypy, "normal" personality, and cigarette smoking

The association between psychoticism (asocial-schizotypy) and cigarette smoking appears to be well established in the literature. However, findings from research examining the relationship between smoking and positive-schizotypy is less consistent, with some studies reporting higher positive-schizotypy in smokers, and other studies reporting no differences. This may be somewhat surprising given that individuals diagnosed with schizophrenia are known to smoke considerably more cigarettes than is typical of the general population, and that positive-schizotypy is phenotypically more closely linked to schizophrenia than asocial-schizotypy. This paper describes necessary further analysis into the relationship between cigarette smoking and multi-dimensional schizotypy (as measured by the Oxford-Liverpool Inventory of Feelings and Experiences), with the additional benefit of “normal” personality data included in the analysis. Personality (both schizotypal and normal) and cigarette smoking data from 182 participants were collated and analysed. Results found that the personality variables associated with asocial-schizotypy were the only reliable predictors of smoking status

Kamin blocking is not disrupted by amphetamine in human subjects.

The effect of oral amphetamine administration on the Kamin-blocking effect in healthy volunteer subjects was investigated. Against predictions, Kamin blocking was not disrupted by either a high or low oral dose of D-amphetamine under conditions which have, in previous studies, led to disruption of a related learning phenomenon (latent inhibition). This lack of effect of amphetamine administration upon Kamin blocking weakens hypotheses that this cognitive process is mediated by the same changes in dopaminergic activity which affect latent inhibition. Currently, the only data which show strong comparative associations between Kamin blocking and latent inhibition are when they are applied to schizophrenic populations. These results may suggest that Kamin blocking and latent inhibition may be measuring different aspects of schizophrenic cognitive dysfunction