Evidence for Non-Anadromous Behaviour of Arctic Charr (Salvelinus alpinus) from Lake Hazen, Ellesmere Island, Northwest Territories, Canada, Based on Scanning Proton Microprobe Analysis of Otolith Strontium Distribution

Scanning proton microprobe analysis was used to determine the distribution of strontium (Sr) in otoliths from arctic charr (Salvelinus alpinus) of known non-anadromous, known anadromous, and unknown life histories. Strontium concentration patterns in otoliths of known non-anadromous charr were low and relatively flat (with little variation) from the core area to the outermost edge of the otolith, while patterns for known anadromous charr were characterized by a similar low, flat region for the first several years of life, followed by marked oscillatory increases and decreases in Sr content for the duration of the fish's life. Small and large forms of Lake Hazen charr of unknown life histories exhibited Sr profiles that were similar to those of the known non-anadromous charr, which strongly suggest that Lake Hazen charr are non-anadromous. These results indicate that Lake Hazen is a "closed" system with energy cycling primarily within the system; this conclusion suggests that a conservative approach would be appropriate for the management of the Lake Hazen charr population.À l'aide d'une sonde protonique à balayage, on a procédé à une analyse afin de déterminer la répartition du strontium (Sr) dans des otolithes prélevés sur des ombles chevaliers (Salvelinus alpinus) ayant eu soit un cycle biologique non anadrome connu, soit un cycle anadrome connu ou un cycle inconnu. Les courbes de concentration en strontium dans les otolithes d'ombles reconnus comme non anadromes étaient faibles et relativement uniformes (montrant peu de fluctuations) en allant du centre de l'otolithe vers la périphérie, tandis que les courbes relatives aux ombles reconnus comme anadromes se caractérisaient par une zone de concentrations faibles et uniformes pour plusieurs des premières années de vie, suivie par des oscillations à la hausse et à la baisse très nettes quant au contenu en Sr pour la durée de vie du poisson. De gros et de petits spécimens d'ombles au cycle biologique inconnu, trouvés dans le lac Hazen, affichaient des profils de Sr semblables à ceux des ombles reconnus comme non anadromes, ce qui suggère fortement que l'omble du lac Hazen est non anadrome. Ces résultats révèlent que le lac Hazen est un système où l'énergie circule surtout en circuit «fermé». Cette conclusion suggère qu'il faudrait adopter une approche prudente quant à la gestion de la population d'ombles du lac Hazen

Narcissism and prosocial behavior

There are many motivations for prosocial behavior, some more altruistic and some more egoistic. We posit that more narcissistic people may perform prosocial acts strategically, for example, to improve their reputations or to receive something in return

Working Memory Training Using Mental Calculation Impacts Regional Gray Matter of the Frontal and Parietal Regions

Training working memory (WM) improves performance on untrained cognitive tasks and alters functional activity. However, WM training's effects on gray matter morphology and a wide range of cognitive tasks are still unknown. We investigated this issue using voxel-based morphometry (VBM), various psychological measures, such as non-trained WM tasks and a creativity task, and intensive adaptive training of WM using mental calculations (IATWMMC), all of which are typical WM tasks. IATWMMC was associated with reduced regional gray matter volume in the bilateral fronto-parietal regions and the left superior temporal gyrus. It improved verbal letter span and complex arithmetic ability, but deteriorated creativity. These results confirm the training-induced plasticity in psychological mechanisms and the plasticity of gray matter structures in regions that have been assumed to be under strong genetic control

The BIOSCI electronic newsgroup network for the biological sciences. Final report, October 1, 1992--June 30, 1996

This is the final report for a DOE funded project on BIOSCI Electronic Newsgroup Network for the biological sciences. A usable network for scientific discussion, major announcements, problem solving, etc. has been created