Reed canarygrass (Phalaris arundinacea L.) is a desirable pasture
grass on wet areas in the Northern United States and Southern Canada,
but it is a serious and troublesome ditchbank weed in the Pacific Northwest
and Rocky Mountain States. The purpose of this study was to learn
more about the development,...
Background: Early childhood is filled with incredible growth in all areas of development and offers a critical period for optimal learning (Lerner, 2002). During this critical period both motor skills (Bouffard, Watkinson, Thompson, Causgrove Dunn, & Romanow, 1996; Clark & Metcalfe, 2002; Lubans, Morgan, Cliff, Barnett, & Okely, 2010; Stodden...
Turbulence resulting from Kelvin–Helmholtz instability in layers of localized stratification and shear is studied by means of direct numerical simulation. Our objective is to present a comprehensive description of the turbulence evolution in terms of simple, conceptual pictures of shear–buoyancy interaction that have been developed previously based on assumptions of...
The energetics of large amplitude, high-frequency nonlinear internal waves (NLIWs) observed over the New Jersey continental shelf are summarized from ship and mooring data acquired in August 2006. NLIW energy was typically on the order of 10⁵ Jm⁻¹, and the wave dissipative loss was near 50 W m⁻¹. However, wave...
Direct numerical simulations are used to compare turbulent diffusivities of heat and salt during the growth and collapse of Kelvin–Helmholtz billows. The ratio of diffusivities is obtained as a function of buoyancy Reynolds number Re[subscript]b and of the density ratio R[subscript]ρ (the ratio of the contributions of heat and salt...
The scale dependence of velocity variances is studied using data collected from a grassland site, a heather site, and four forested sites. The dependence of velocity variances on averaging time, used to define the fluctuation quantities, is modeled. The crosswind velocity variance is emphasized, because it is more difficult to...
Nitrogen fertilization of seedling legumes is a controversial practice intended to provide N to the plant during periods when seed N, soil N, and N₂ fixation may not meet plant requirements; eg. prenodulation, postharvest, or in the event of an inoculation failure. Field experiments were conducted in 3 consecutive years...
Nutrient limitation constrains tree growth in many managed forests. Nitrogen (N) is the most common limiting nutrient, but high N supply can shift limitation to other nutrients, particularly phosphorus (P) and the base cations calcium (Ca), magnesium (Mg), and potassium (K). As different soil minerals have different capacities to supply...
Despite a large and multifaceted effort to understand the vast landscape of phenotypic data, their current form inhibits productive data analysis. The lack of a community-wide, consensus-based, human- and machine-interpretable language for describing phenotypes and their genomic and environmental contexts is perhaps the most pressing scientific bottleneck to integration across...
Centuries of continuous grain cropping in northern Africa have
reduced N levels in soils to a degree such that agricultural production
is now largely dependent upon nitrogen fertilizer. Through the
identification of highly effective legume and Rhizobium strain combinations,
the production of protein-rich livestock forage and green
manure can be...