The metrology of spherical shells using synchrotron x ray microtomography

With recent advances in solid state imaging technology and the increasing availability of synchrotron x-ray radiation sources, synchrotron x-ray microtomography is emerging as a nondestructive technique for the evaluation of the structure and composition of small specimens with spatial resolution in the micron range. Synchrotron radiation offers the following advantages over conventional x-ray sources: high brightness, continuous emission which is tunable over a large energy range, faster data collection rates, and a highly collimated beam of large cross section permitting the illumination of large specimens. Synchrotron x-ray microtomography enables the structure of individual spheres to be evaluated in order to reveal the concentricity and sphericity of the internal void and the uniformity of the shell wall in the case of high quality spherical shells for Sandia National Laboratories' Inertial Confinement Fusion project

USING SATELLITE IMAGERY IN PREDICTING KANSAS FARMLAND VALUES

Can remotely sensed imagery improve hedonic land price models? A remotely sensed variable was added to a hedonic farmland value model as a proxy for land productivity. Land cover data were used to obtain urban and recreational effects as well. The urban and recreational effects were statistically significant but economically small. The remotely sensed productivity variable was statistically significant and economically large, indicating that knowing the "greenness" of the land increased the explanatory power of the hedonic price model. Thus, depending upon the cost of this information, including remotely sensed imagery in traditional hedonic land price models is economically beneficial.Land Economics/Use,

Differential localization of glutamate receptor subunits at the drosophila neuromuscular junction

The subunit composition of postsynaptic neurotransmitter receptors is a key determinant of synaptic physiology. Two glutamate receptor subunits, Drosophila glutamate receptor IIA (DGluRIIA) and DGluRIIB, are expressed at the Drosophila neuromuscular junction and are redundant for viability, yet differ in their physiological properties. We now identify a third glutamate receptor subunit at the Drosophila neuromuscular junction, DGluRIII, which is essential for viability. DGluRIII is required for the synaptic localization of DGluRIIA and DGluRIIB and for synaptic transmission. Either DGluRIIA or DGluRIIB, but not both, is required for the synaptic localization of DGluRIII. DGluRIIA and DGluRIIB compete with each other for access to DGluRIII and subsequent localization to the synapse. These results are consistent with a model of a multimeric receptor in which DGluRIII is an essential component. At single postsynaptic cells that receive innervation from multiple motoneurons, DGluRIII is abundant at all synapses. However, DGluRIIA and DGluRIIB are differentially localized at the postsynaptic density opposite distinct motoneurons. Hence, innervating motoneurons may regulate the subunit composition of their receptor fields within a shared postsynaptic cell. The capacity of presynaptic inputs to shape the subunit composition of postsynaptic receptors could be an important mechanism for synapse-specific regulation of synaptic function and plasticity

Adaptive management for ecosystem services

Management of natural resources for the production of ecosystem services, which are vital for human well-being, is necessary even when there is uncertainty regarding system response to management action. This uncertainty is the result of incomplete controllability, complex internal feedbacks, and nonlinearity that often interferes with desired management outcomes, and insufficient understanding of nature and people. Adaptive management was developed to reduce such uncertainty. We present a framework for the application of adaptive management for ecosystem services that explicitly accounts for cross-scale tradeoffs in the production of ecosystem services. Our framework focuses on identifying key spatiotemporal scales (plot, patch, ecosystem, landscape, and region) that encompass dominant structures and processes in the system, and includes within- and cross-scale dynamics, ecosystem service tradeoffs, and management controllability within and across scales. Resilience theory recognizes that a limited set of ecological processes in a given system regulate ecosystem services, yet our understanding of these processes is poorly understood. If management actions erode or remove these processes, the system may shift into an alternative state unlikely to support the production of desired services. Adaptive management provides a process to assess the underlying within and cross-scale tradeoffs associated with production of ecosystem services while proceeding with management designed to meet the demands of a growing human population

Ecosystem size predicts social-ecological dynamics

Recreational fisheries are complex adaptive systems that are inherently difficult to manage because of heterogeneous user groups (consumptive vs. nonconsumptive) that use patchily distributed resources on the landscape (lakes, rivers, coastlines). There is a need to identify which system components can effectively predict and be used to manage nonlinear and cross-scale dynamics within these systems. We examine how ecosystem size or water body size can be used to explain complicated and elusive angler-resource dynamics in recreational fisheries. Water body size determined angler behavior among 48 Nebraska, U.S.A. water bodies during an 11- year study. Angler behavior was often unique and nonlinear across water body sizes. For example, anglers spent more time fishing and harvested more fish at larger water bodies compared to smaller water bodies. Time fished increased across smaller water bodies, but reached a threshold at larger water bodies. The number of fish released increased as a function of water body size across smaller water bodies and then plateaued. Subtle changes in water body size caused abrupt changes in angler behavior, that is, water body size structures angler-resource dynamics in recreational fisheries. We believe that including water body size, a simple and easily measured metric, in fisheries management will increase effectiveness of cross-scale actions and minimize unintended consequences for recreational fisheries. Applying uniform management actions, e.g., harvest regulations, across small and large water bodies may elicit contrasting anglerresource responses. Water body size may also be useful for understanding angler typologies. Based on our findings, we expect that ecosystem size is a prominent and valuable system component that will determine and explain coupled user-resource dynamics in other complex adaptive systems

Adaptive management for ecosystem services

Management of natural resources for the production of ecosystem services, which are vital for human well-being, is necessary even when there is uncertainty regarding system response to management action. This uncertainty is the result of incomplete controllability, complex internal feedbacks, and nonlinearity that often interferes with desired management outcomes, and insufficient understanding of nature and people. Adaptive management was developed to reduce such uncertainty. We present a framework for the application of adaptive management for ecosystem services that explicitly accounts for cross-scale tradeoffs in the production of ecosystem services. Our framework focuses on identifying key spatiotemporal scales (plot, patch, ecosystem, landscape, and region) that encompass dominant structures and processes in the system, and includes within- and cross-scale dynamics, ecosystem service tradeoffs, and management controllability within and across scales. Resilience theory recognizes that a limited set of ecological processes in a given system regulate ecosystem services, yet our understanding of these processes is poorly understood. If management actions erode or remove these processes, the system may shift into an alternative state unlikely to support the production of desired services. Adaptive management provides a process to assess the underlying within and cross-scale tradeoffs associated with production of ecosystem services while proceeding with management designed to meet the demands of a growing human population

Water as a trophic currency in dryland food webs

Water is essential for life on Earth, yet little is known about how water acts as a trophic currency, a unit of value in determining species interactions in terrestrial food webs. We tested the relative importance of groundwater and surface water in riparian food webs by manipulating their availability in dryland floodplains. Primary consumers (crickets) increased in abundance in response to added surface water and groundwater (contained in moist leaves), and predators (spiders and lizards) increased in abundance in response to added surface water, in spite of the presence of a river, an abundant water source. Moreover, the relative magnitude of organism responses to added water was greatest at the most arid site and lowest at the least arid site, mirroring cricket recruitment, which was greatest at the least arid site and lowest at the most arid site. These results suggest that water may be a key currency in terrestrial dryland food webs, which has important implications for predicting ecosystem responses to human‐ and climate‐related changes in hydrology and precipitation

Magneto-optical spectra of closely spaced magnetite nanoparticles

The Faraday rotation spectrum of composites containing magnetite nanoparticles is found to be dependent on the interparticle spacing of the constituent nanoparticles. The composite materials are prepared by combining chemically synthesized Fe 3O4 smagnetited nanoparticles s8-nm diameterd and polysmethylmethacrylated . Composites are made containing a range of nanoparticle concentrations. The peak of the main spectral feature depends on nanoparticle concentration; this peak is observed to shift from approximately 470 nm for sdilute compositesd to 540 nm concentrated . We present a theory based on the discrete-dipole approximation which accounts for optical coupling between magnetite particles. Qualitative correlations between theoretical calculations and experimental data suggest that the shifts in spectral peak position depend on both interparticle distance and geometrical configuratio

Optical Emission Spectroscopy Diagnostics of Cold Plasmas for Food Sterilization

There is a growing need for economical, effective, and safe methods of sterilizing fresh produce. The most common method is a chlorine wash, which is expensive and may introduce carcinogens. High voltage cold atmospheric pressure plasmas are a promising solution that has demonstrated a germicidal effect; however, the responsible chemical mechanisms and reaction pathways are not fully understood. To elucidate this chemistry, we used optical emission spectroscopy to measure the species produced in the plasma generated by a 60 Hz pulsed dielectric barrier discharge in a plastic box containing various fill gases (He, N2, CO2, dry air, or humid air). In addition to estimating chemical species concentrations, we performed preliminary calculations of electronic, vibrational, rotational, and translational temperatures