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Full-Text Articles in Biology
Trophic Cascades, Nutrients, And Lake Productivity: Whole-Lake Experiments, Stephen R. Carpenter, Jonathan J. Cole, James R. Hodgson, James F. Kitchell, Michael L. Pace, Darren Bade, Kathryn L. Cottingham
Trophic Cascades, Nutrients, And Lake Productivity: Whole-Lake Experiments, Stephen R. Carpenter, Jonathan J. Cole, James R. Hodgson, James F. Kitchell, Michael L. Pace, Darren Bade, Kathryn L. Cottingham
Dartmouth Scholarship
Responses of zooplankton, pelagic primary producers, planktonic bacteria, and CO2 exchange with the atmosphere were measured in four lakes with contrasting food webs under a range of nutrient enrichments during a seven-year period. Prior to enrichment, food webs were manipulated to create contrasts between piscivore dominance and planktivore dominance. Nutrient enrichments of inorganic nitrogen and phosphorus exhibited ratios of N:P > 17:1, by atoms, to maintain P limitation. An unmanipulated reference lake, Paul Lake, revealed baseline variability but showed no trends that could confound the interpretation of changes in the nearby manipulated lakes. Herbivorous zooplankton of West Long Lake (piscivorous fishes) …
Chromosome Movement In Mitosis Requires Microtubule Anchorage At Spindle Poles, Michael B. Gordon, Louisa Howard, Duane A. Compton
Chromosome Movement In Mitosis Requires Microtubule Anchorage At Spindle Poles, Michael B. Gordon, Louisa Howard, Duane A. Compton
Dartmouth Scholarship
Anchorage of microtubule minus ends at spindle poles has been proposed to bear the load of poleward forces exerted by kinetochore-associated motors so that chromosomes move toward the poles rather than the poles toward the chromosomes. To test this hypothesis, we monitored chromosome movement during mitosis after perturbation of nuclear mitotic apparatus protein (NuMA) and the human homologue of the KIN C motor family (HSET), two noncentrosomal proteins involved in spindle pole organization in animal cells. Perturbation of NuMA alone disrupts spindle pole organization and delays anaphase onset, but does not alter the velocity of oscillatory chromosome movement in prometaphase. …
Genes, Categories, And Species: The Evolutionary And Cognitive Causes Of The Species Problem, Michael Dietrich
Genes, Categories, And Species: The Evolutionary And Cognitive Causes Of The Species Problem, Michael Dietrich
Dartmouth Scholarship
Review of Genes, Categories, and Species: The Evolutionary and Cognitive Causes of the Species Problem by Jody Hey.
Firefly Flashing Is Controlled By Gating Oxygen To Light-Emitting Cells, G. S. Timmins, F. J. Robb, C. M. Wilmot, S. K. Jackson, H. M. Swartz
Firefly Flashing Is Controlled By Gating Oxygen To Light-Emitting Cells, G. S. Timmins, F. J. Robb, C. M. Wilmot, S. K. Jackson, H. M. Swartz
Dartmouth Scholarship
Although many aspects of firefly bioluminescence are understood, the mechanism by which adult fireflies produce light as discrete rapid flashes is not. Here we examine the most postulated theory, that flashing is controlled by gating oxygen access to the light-emitting cells (photocytes). According to this theory, the dark state represents repression of bioluminescence by limiting oxygen, which is required for bioluminescence; relief from this repression by transiently allowing oxygen access to the photocytes allows the flash. We show that normobaric hyperoxia releases the repression of light emission in the dark state of both spontaneously flashing and non-flashing fireflies, causing continual …