Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
58
result(s) for
"Gerrard, Jon"
Sort by:
In Memoriam: Gary Bortolotti, 1954–2011
On the one hand I saw myself as an intruder, an unwelcome tourist in a foreign land. Later, Gary and his students conducted research on American Kestrels, building and placing about 375 kestrel nest boxes near Besnard Lake.
Journal Article
Histamine is an Intracellular Messenger Mediating Platelet Aggregation
Inhibition of human platelet aggregation by N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine-HCl (DPPE), a novel antagonist of histamine binding, suggested that histamine might serve a critical role in cell function. Phorbol-12-myristate-13-acetate (PMA) or collagen was found to increase platelet histamine content in parallel with promotion of aggregation. Inhibitors of histidine decarboxylase (HDC) suppressed both aggregation and the elevation of histamine content, whereas DPPE inhibited aggregation only. In saponin-permeabilized platelets, added histamine reversed the inhibition by DPPE or HDC inhibitors on aggregation induced by PMA or collagen. The results indicate a role for histamine as an intracellular messenger, which in platelets promotes aggregation.
Journal Article
Estimating Closed Population Size and Number of Marked Animals from Sighting Data
We describe a new estimator of population size that can be formed when independent sightings are made of marked and unmarked animals in a closed population where a subset of the population is individually marked. Each marked animal must bear a unique mark but the number of marked animals alive in the population is unknown. The estimate can be used when no recaptures or removals of animals are possible during the experiment. An example is estimating the number of immature bald eagles (Haliaeetus leucocephalus) on a lake some years after banding of nestlings. We derive the maximum likelihood estimates for population size and number of marks, and we show how to develop confidence intervals and perform goodness-of-fit tests. Criteria are developed for determining the number of sightings required to yield satisfactory estimates.
Journal Article
Factors Influencing Bald Eagle Densities in Northcentral Saskatchewan
Bald eagle (Haliaeetus leucocephalus) densities vary throughout North America, but reasons for these differences are poorly understood and may be important for directing management practices. Thus, we evaluated the influence of forest nesting habitat and food abundance on the densities of bald eagles on 2 lakes in northcentral Saskatchewan, Canada. We found no evidence that nest-site availability influenced the number of eagles on either lake. Differences in the food supply were investigated both directly by netting fish, and indirectly, through information obtained from biological surveys at Besnard and Nemeiben Lakes. Cisco (Coregonus artedii), a key prey species for eagles, were more common and larger (P < 0.05) in Besnard Lake. Evidence from mineral content, plankton, benthic fauna biomass, and abundance of fish, support the contention that food abundance was the most important factor contributing to density differences of bald eagles between Besnard and Nemeiben Lakes. Food supply should be an integral part of any management plan aimed at protecting or enhancing bald eagle habitat.
Journal Article
Science Policy in Canada
In an editorial, Gerrard explains how Canada's 1998 budget reversed a trend of three years of funding cuts to its three research granting councils and provided a turnaround for basic science. A clear plan and funding approach is needed next for international science participation.
Journal Article