Quaking aspen (Populus tremuloides) sustainability is a topic of intense interest in forest ecology.
Reports range from declines to persisting or increasing coverage in some areas. Moreover, there is little
agreement on ultimate factors driving changes. Low aspen recruitment has been attributed to climate
patterns, past management, herbivore increases, competitive...
Like most ecological communities, aspen (Populus tremuloides) forests are influenced by a synergy of bottom-up (resources-driven) and top-down (predator-driven) processes. Since the 1920s, ecologists have observed the decline of many aspen communities throughout the Intermountain West. The extent and possible drivers of this decline are topics of much recent scientific...
The relationship between nitrogen (N) availability and the growth of macroalgae in a seasonal upwelling region (Yaquina Head, Oregon, USA) was investigated. Water column nutrient concentrations were relatively high and stable during the winter, decreased in early spring, and were highly variable in the summer and early fall. Periods of...
Zebrafish are a powerful model organism to study disease. Like other animal models, Danio rerio colonies are at risk of pathogenic infection. Microsporidia, a group of intracellular fungus-like parasites, are one potential threat. Microsporidian spores germinate and spread causing pathological changes in the central nervous system, skeletal muscle, and other...
Plant species in the family Solanaceae are the usual hosts of potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Psylloidea: Triozidae). However, the psyllid has also been shown to develop on some species of Convolvulaceae (bindweeds and morning glories). Developmental success on Convolvulaceae is surprising given the rarity of psyllid species worldwide...
The formation of hydrogen peroxide (H₂O₂) by the FAD-dependent α-glycerophosphate oxidase (GlpO), is important for the pathogenesis of Streptococcus pneumoniae and Mycoplasma pneumoniae. The structurally known GlpO from Streptococcus sp. (SspGlpO) is similar to the pneumococcal protein (SpGlpO) and provides a guide for drug design against that target. However, M....
This study presents a methods evaluation and intercalibration of active fluorescence-based measurements of the quantum yield (ϕ'ₚₛᵢᵢ) and absorption coefficient (aₚₛᵢᵢ) of photosystem II (PSII) photochemistry. Measurements of ϕ'ₚₛᵢᵢ, aₚₛᵢᵢ, and irradiance (E) can be scaled to derive photosynthetic electron transport rates (Pₑ), the process that fuels phytoplankton carbon fixation...
Background A novel equine parvovirus (EqPV-H) was recently discovered in the equine liver with Theiler's disease. Objectives To determine the prevalence of EqPV-H infection in naturally occurring Theiler's disease cases and in-contact horses in the absence of historical equine biologic product administration. Animals Ten cases of Theiler's disease from 6...
Aldo Leopold, perhaps best known for his revolutionary and poignant essays about nature, was also an eloquent advocate during the 1930s and 1940s
of the need to maintain wolves and other large carnivores in forest and range ecosystems.He indicated that their loss set the stage for ungulate irruptions
and ecosystem...
Gray wolves (Canis lupus) were reintroduced into Yellowstone National Park in 1995-96, thus completing the park’s large predator guild. In the fall of 2010, approximately 15 years after wolf reintroduction, we sampled ten genera/species of berry-producing shrubs within 97 aspen (Populus tremuloides) stands in the park’s northern ungulate winter range....