Double-crop grain sorghum after winter wheat harvest is a common cropping system in the southern plains region. Palmer amaranth is a troublesome weed in double-crop grain sorghum in Kansas. Populations resistant to various herbicides (e.g., atrazine, glyphosate, metsulfuron, pyrasulfotole) have made Palmer amaranth management even more difficult for producers. To evaluate control of atrazine-resistant and atrazine-susceptible Palmer amaranth in double-crop grain sorghum, we assessed 14 herbicide programs, of which 8 were PRE only and 6 were PRE followed by (fb) POST applications. Visible ratings of Palmer amaranth control were taken at 3 and 8 wk after planting (WAP) grain sorghum. PRE treatments containing very-long-chain fatty acid (VLCFA)–inhibiting herbicides provided 91% control of atrazine-resistant Palmer amaranth 3 WAP, and reduced weed density 8 WAP compared to atrazine-only PRE treatments. PRE fb POST treatments, especially those that included VLCFA-inhibiting herbicides, provided greater control (71% to 93%) of both atrazine-resistant and atrazine-susceptible Palmer amaranth, respectively, at 8 WAP compared to PRE treatments alone (59% to 79%). These results demonstrated the utility of VLCFA-inhibiting herbicides applied PRE and in a layered PRE fb POST approach in controlling atrazine-resistant Palmer amaranth, as well as the importance of an effective POST application following residual PRE herbicides for controlling both atrazine-resistant and atrazine-susceptible Palmer amaranth in double-crop grain sorghum.

Synchrotron X-ray diffraction was used to monitor the hydrothermal precipitation of akaganeite (β-FeOOH) and its transformation to hematite (Fe2O3) in situ. Akaganeite was the first phase to form and hematite was the final phase in our experiments with temperatures between 150 and 200 °C. Akaganeite was the only phase that formed at 100 °C. Rietveld analyses revealed that the akaganeite unit-cell volume contracted until the onset of dissolution, and subsequently expanded. This reversal at the onset of dissolution was associated with a substantial and rapid increase in occupancy of the Cl site, perhaps by OH− or Fe3+. Rietveld analyses supported the incipient formation of an OH-rich, Fe-deficient hematite phase in experiments between 150 and 200 °C. The inferred H concentrations of the first crystals were consistent with “hydrohematite.” With continued crystal growth, the Fe occupancies increased. Contraction in both a- and c-axes signaled the loss of hydroxyl groups and formation of a nearly stoichiometric hematite.

A voluntary program is developed to achieve environmental goals through the self-interested choices of farmers under environmental risk and asymmetric information. Farmers behave to maximize expected net returns, and environmental quality standards are formulated through chance constraints. Because the government may not know each farmer's soil type, policy options must be self-selecting. The model is applied empirically to nitrate leaching and runoff from corn production in three New York regions. Asymmetric information between producers and the government would impose additional cost burdens on society, but these costs are modest in the context of other farm programs.

Because of the decline of the Ogallala Aquifer, water districts, regional water managers, and state water officers are becoming increasingly interested in conservation policies. This study evaluates both short-term and long-term water rights buyout policies. This research develops dynamic production functions for the major crops in the Texas Panhandle. The production functions are incorporated into optimal temporal allocation models that project annual producer behavior, crop choices, water use, and aquifer declines over 60 years. Results suggest that long-term buyouts may be more economically efficient than short-term buyouts.

This research analyzes two groundwater conservation policies in the Kansas High Plains located within the Ogallala aquifer: 1) cost-share assistance to increase irrigation efficiency; and 2) incentive payments to convert irrigated crop production to dryland crop production. To compare the cost-effectiveness of these two policies, a dynamic model simulated a representative irrigator's optimal technology choice, crop selection, and irrigation water use over time. The results suggest that the overall water-saving effectiveness can be improved when different policy tools are considered under different conditions. High prevailing crop prices greatly reduce irrigators' incentive to give up irrigation and therefore cause low enrollment and ineffectiveness of the incentive payment program. In areas with low aquifer-saturated thickness, the incentive payment program is more effective, whereas in areas with relatively higher water availability, the cost-share program could be a better choice.

This paper develops a framework for analysing intergovernmental relationships around greenhouse gas (GHG) mitigation policies along a cooperation-conflict spectrum that affects the probability of their enactment. Cooperative policies, such as federal fiscal transfers to sub-national governments, facilitate enactment. Coordination policies, including enabling and funding mechanisms, promote interdependence between jurisdictions. Competitive policies, such as federal performance standards and price mechanisms, increase political conflict over authority. We categorise 23 policies developed by over 1,500 state stakeholders into the cooperation/coordination/conflict taxonomy. If scaled to the national level, these policies could reduce GHG emissions by over 3 billion tonnes by 2020 and generate nearly 2.2 million jobs (1.19 per cent above baseline projections). Nearly two-thirds of the job gains are from coordinated and cooperative policy options that are unlikely to occur under the status quo policy process. We recommend a national climate action planning process to reduce GHG emissions while increasing aggregate economic efficiency.

We have developed a 350 μm radiometer to perform automated site testing in remote regions of Antarctica. In summer 2000–2001 the instrument operated at Concordia, a new station under construction at Dome C on the Antarctic Plateau. We present the results, and compare them with the atmospheric opacity measured at the South Pole in the same five-week period. During these five weeks, observing conditions at Dome C were, on average, substantially better than those at the South Pole.

We report an experimental study of photocarrier lifetime, transport, and excitation spectra in silicon-on-insulator doped with sulfur far above thermodynamic saturation. The spectral dependence of photocurrent in coplanar structures is consistent with photocarrier generation throughout the hyperdoped and undoped sub-layers, limited by collection of holes transported along the undoped layer. Holes photoexcited in the hyperdoped layer are able to diffuse to the undoped layer, implying (μτ)h ∼ 5 × 10−9 cm2/V. Although high absorptance of hyperdoped silicon is observed from 1200 to 2000 nm in transmission experiments, the number of collected electrons per absorbed photon is 10−4 of the above-bandgap response of the device, consistent with (μτ)e < 1 × 10−7cm2/V.

There are many reasons for seeking to create a global database with which to record the outcomes of therapy for congenital heart disease. Such a database can function as a tool to support a variety of purposes: