Tree-ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary environmental...
Paleoclimate proxies based on the measurement of xylem cell anatomy have rarely been developed across the temperature range of a species or applied to wood predating the most recent millennium. Here we describe wood anatomy-based proxies for spring temperatures in central North America from modern bur oaks (Quercus macrocarpa Michx.)....
Rising atmospheric [CO₂], cₐ, is expected to affect stomatal regulation of leaf gas-exchange of woody plants, thus influencing energy fluxes as well as carbon (C), water, and nutrient cycling of forests. Researchers have proposed various strategies for stomatal regulation of leaf gas-exchange that include maintaining a constant leaf internal [CO₂],...
An adiabatic calorimeter operating over the range 5 to 300 K has
been automated. Instrumentation includes computer controlled data
acquisition, a low-thermal emf multiplexer for switching low-level dc
signals, and automatic analog shield controls. Temperature
measurements are made with platinum and germanium resistance
thermometers, and the thermometer resistances are determined...
Nanomaterials are expected to enable significant advances in several technological fields in coming years. Among them, electronics has emerged as one of the most likely benefactors from the ability to control matter on the nanometer-scale. For many electronic devices synthesized nanomaterials must be integrated into thin film structures. Vapor-based deposition...
The design, development, and utilization of a direct shear test
apparatus is presented in this thesis. The effectiveness of the
device for determining the friction angle stress state parameter is
studied. Two materials, alumina and uranium dioxide, were tested.
Alumina microspheres were employed in the initial experiments
to simulate the...
In this case, the student is a senior partner in Corporate Planning Group (CPG), a strategy-consulting firm. The principals of National Systems, Inc. (the company) have retained CPG to develop a 5-year strategic marketing program to (1) strengthen current markets and (2) develop new markets for the company’s line of...
Roots are considered to be the major production site of amino acids that appear in the xylem sap of conifers. The carbon skeleton of amino acids is derived from photosynthetically reduced carbon dioxide while the nitrogen is derived from the inorganic forms taken up by the roots. An experiment was...
This research assesses prescribed burning as a habitat management
technique in wetlands and associated upland communities of Malheur
National Wildlife Refuge, southeastern Oregon. Experimental burns
were conducted to evaluate fire behavior and effects in wetland and
upland habitats, and, fire effects on Cirsium arvense. Wetland plant
communities were monotypic stands...