Watershed Vulnerability To Herbicide Transport in Northern Missouri and Southern Iowa Streams

Herbicide contamination of streams has been well documented, but little is currently known about the specific factors affecting watershed vulnerability to herbicide transport. The primary objectives of this study were (1) to document herbicide occurrence and transport from watersheds in the northern Missouri/ southern Iowa region; (2) to quantify watershed vulnerability to herbicide transport and relate vulnerability to soil properties; and (3) to compute the contribution of this region to the herbicide load of the Missouri and Mississippi Rivers. Grab samples were collected under baseflow and runoff conditions at 21 hydrologic monitoring stations between April 15 and July 15 from 1996 to 1999. Samples were analyzed for commonly used soil-applied herbicides (atrazine, cyanazine, acetochlor, alachlor, metolachlor, and metribuzin) and four triazine metabolites (deisopropylatrazine, deethylatrazine, hydroxyatrazine, and cyanazine amide). Estimates of herbicide load and relative losses were computed for each watershed. Median parent herbicide losses, as a percentage of applied, ranged from 0.33 to 3.9%; loss rates that were considerably higher than other areas of the United States. Watershed vulnerability to herbicide transport, measured as herbicide load per treated area, showed that the runoff potential of soils was a critical factor affecting herbicide transport. Herbicide transport from these watersheds contributed a disproportionately high amount of the herbicide load to both the Missouri and Mississippi Rivers. Based on these results, this region of the Corn Belt is highly vulnerable to transport of herbicides from fields to streams, and it should be targeted for implementation of management practices designed to reduce herbicide losses in surface runoff

Hierarchy of the Selberg zeta functions

We introduce a Selberg type zeta function of two variables which interpolates several higher Selberg zeta functions. The analytic continuation, the functional equation and the determinant expression of this function via the Laplacian on a Riemann surface are obtained.Comment: 14 page

Functional renormalization group in the broken symmetry phase: momentum dependence and two-parameter scaling of the self-energy

We include spontaneous symmetry breaking into the functional renormalization group (RG) equations for the irreducible vertices of Ginzburg-Landau theories by augmenting these equations by a flow equation for the order parameter, which is determined from the requirement that at each RG step the vertex with one external leg vanishes identically. Using this strategy, we propose a simple truncation of the coupled RG flow equations for the vertices in the broken symmetry phase of the Ising universality class in D dimensions. Our truncation yields the full momentum dependence of the self-energy Sigma (k) and interpolates between lowest order perturbation theory at large momenta k and the critical scaling regime for small k. Close to the critical point, our method yields the self-energy in the scaling form Sigma (k) = k_c^2 sigma^{-} (k | xi, k / k_c), where xi is the order parameter correlation length, k_c is the Ginzburg scale, and sigma^{-} (x, y) is a dimensionless two-parameter scaling function for the broken symmetry phase which we explicitly calculate within our truncation.Comment: 9 pages, 4 figures, puplished versio

Stream bank erosion rates of small Missouri streams

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.Sedimentation of surface waters in the United States is a significant environmental concern. Investigating land use impacts on stream bank erosion rates is intended to lead to the development of improved management practices and provide the basis for targeting the placement of management practices to mitigate this problem. The overall objective of this research was to determine the effect of stream order, adjacent land use, and season on stream bank erosion rates. Study sites were established in 2007 and 2008 within Crooked and Otter Creek watersheds, two claypan watersheds located in northeast Missouri. Detailed site information was recorded, including eroded stream bank length, soil descriptions, gullies, debris dams, cattle access areas, and point bars. A factorial experimental design was implemented with four land uses (cropped, forest, pasture, and riparian forest) and three stream orders (1st, 2nd, 3rd). Each treatment was replicated three times for each stream order, except for the cropped 3rd order treatment as only one suitable treatment could be found. Erosion pins were installed based on bank height and length at each site to measure bank erosion/deposition rates. The effect of different seasons was assessed by measuring the length of the exposed pins three times per year (March, July, and November). Statistical analyses were performed to determine the effect of stream order, land use, and season on erosion rates. The results showed that the seasonal effect was highly significant, with much greater erosion rates in the winter of 2008 compared to the other seasons. Land use was significant when low magnitude deposition was observed and was not significant in any of the seasons in which erosion occurred.C.C. Willett (1), S.A. Berges (2), R.N. Lerch (3), and R.C. Schultz (2) ; 1. Department of Soil, Environmental and Atmospheric Sciences, University of Missouri. 2. Department of Natural Resource, Ecology and Management, Iowa State University. 3. USDA-Agricultural Research Service, Cropping Systems and Water Quality Research Unit, Columbia, MO.Includes bibliographical references

Controlling swine odor with windbreaks

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.Emissions of malodor from swine facilities are an increasing environmental concern for the swine producers and nearby local communities. Use of natural windbreaks for odor abatement is recent and the science in support of using windbreaks for this purpose is limited. To provide sound science to the study of windbreaks and odor control, the University of Missouri Center for Agroforestry initiated a study in 2007 to evaluate the effects of windbreaks on transport of odors. A 3-row windbreak configuration was implemented consisting of pitch-loblolly pine (Pinus rigida_P. taeda), a conifer, on the inside row closest to the farrowing house; red maple (Acer rubrum) alternating with pin oak (Quercus palustris) a deciduous hardwood species that retains many of its leaves throughout much of the winter, as the middle row and; Viburnum 'Allegheny' (Viburnum rhytidophyllum X V. lantana), a semi-evergreen shrub that quickly reaches heights of 10 to 15 feet, as the outside row. Before the windbreak takes effect, air samples are being taken at varying distances from the facility (up to a mile radius) to monitor the baseline background concentrations of odorous gasses including ammonia (NH3), hydrogen sulfide (H2S), major volatile organic compounds (VOCs) and particulates. The spatial distribution and temporal variation in concentrations of these malodorous compounds have been characterized and mapped. This baseline information will be used for evaluating the impact of the windbreak on odor concentrations and movement over time.Chung-Ho Lin (1), Dusty D. Walter (1), Harold E. Garrett (1) and Robert N. Lerch (2). 1. Center for Agroforestry, University of Missouri, Columbia, MO 65211. 2. U.S. Department of Agriculture-Agricultural Research Service, Cropping Systems and Water Quality Research Unit, Columbia, Missouri 65211.Includes bibliographical references

The Tumor Suppressor HHEX Inhibits Axon Growth when Prematurely Expressed in Developing Central Nervous System Neurons

Neurons in the embryonic and peripheral nervoussystem respond to injury by activating transcriptional programs supportive of axon growth, ultimately resulting in functional recovery. In contrast, neurons in the adult central nervous system (CNS) possess a limited capacity to regenerate axons after injury, fundamentally constraining repair. Activating pro-regenerative gene expression in CNS neurons is a promising therapeutic approach, but progress is hampered by incomplete knowledge of the relevant transcription factors. An emerging hypothesis is that factors implicated in cellular growth and motility outside the nervous system may also control axon growth in neurons. We therefore tested sixty-nine transcription factors, previously identified as possessing tumor suppressive or oncogenic properties in non-neuronal cells, in assays of neurite outgrowth. This screen identified YAP1 and E2F1 as enhancers of neurite outgrowth, and PITX1, RBM14, ZBTB16, and HHEX as inhibitors. Follow-up experiments are focused on the tumor suppressor HHEX, one of the strongest growth inhibitors. HHEX is widely expressed in adult CNS neurons, including corticospinal tract neurons after spinal injury, but is present only in trace amounts in immature cortical neurons and adult peripheral neurons. HHEX overexpression in early postnatal cortical neurons reduced both initial axonogenesis and the rate of axon elongation, and domain deletion analysis strongly implicated transcriptional repression as the underlying mechanism. These findings suggest a role for HHEX in restricting axon growth in the developing CNS, and substantiate the hypothesis that previously identified oncogenes and tumor suppressors can play conserved roles in axon extension

Verification of Experimental Techniques for Flow Surface Determination

The concept of a yield surface is central to the mathematical formulation of a classical plasticity theory. However, at elevated temperatures, material response can be highly time-dependent, which is beyond the realm of classical plasticity. Viscoplastic theories have been developed for just such conditions. In viscoplastic theories, the flow law is given in terms of inelastic strain rate rather than the inelastic strain increment used in time-independent plasticity. Thus, surfaces of constant inelastic strain rate or flow surfaces are to viscoplastic theories what yield surfaces are to classical plasticity. The purpose of the work reported herein was to validate experimental procedures for determining flow surfaces at elevated temperatures. Since experimental procedures for determining yield surfaces in axial/torsional stress space are well established, they were employed -- except inelastic strain rates were used rather than total inelastic strains. In yield-surface determinations, the use of small-offset definitions of yield minimizes the change of material state and allows multiple loadings to be applied to a single specimen. The key to the experiments reported here was precise, decoupled measurement of axial and torsional strain. With this requirement in mind, the performance of a high-temperature multi-axial extensometer was evaluated by comparing its results with strain gauge results at room temperature. Both the extensometer and strain gauges gave nearly identical yield surfaces (both initial and subsequent) for type 316 stainless steel (316 SS). The extensometer also successfully determined flow surfaces for 316 SS at 650 C. Furthermore, to judge the applicability of the technique for composite materials, yield surfaces were determined for unidirectional tungsten/Kanthal (Fe-Cr-Al)

Remember the past: a comparison of time-adaptive training schemes for non-homogeneous regression

Non-homogeneous regression is a frequently used post-processing method for increasing the predictive skill of probabilistic ensemble weather forecasts. To adjust for seasonally varying error characteristics between ensemble forecasts and corresponding observations, different timeadaptive training schemes, including the classical sliding training window, have been developed for non-homogeneous regression. This study compares three such training approaches with the sliding-window approach for the application of post-processing near-surface air temperature forecasts across central Europe. The predictive performance is evaluated conditional on three different groups of stations located in plains, in mountain foreland, and within mountainous terrain, as well as on a specific change in the ensemble forecast system of the European Centre for Medium-Range Weather Forecasts (ECMWF) used as input for the post-processing. The results show that time-adaptive training schemes using data over multiple years stabilize the temporal evolution of the coefficient estimates, yielding an increased predictive performance for all station types tested compared to the classical sliding-window approach based on the most recent days only. While this may not be surprising under fully stable model conditions, it is shown that “remembering the past” from multiple years of training data is typically also superior to the classical sliding-window approach when the ensemble prediction system is affected by certain model changes. Thus, reducing the variance of the non-homogeneous regression estimates due to increased training data appears to be more important than reducing its bias by adapting rapidly to the most current training data only

Effects of combined conservation practices on soil and water quality in the Central Mississippi River Basin

Conventional cultivation of claypan soils leads to soil and water quality degradation because of high runoff and associated soil erosion. The Goodwater Creek Experimental Watershed, which is part of the USDA Agricultural Research Service Benchmark Conservation Effects Assessment Project, Watershed Assessment Studies, was established to address these issues. Plot studies have highlighted trade-offs between erosion control and herbicide or nutrient runoff. There is a need for long-term field-scale evaluation of combined practices that reduce sediment, nutrient, and herbicide losses by runoff. A 36 ha field located in Missouri was under a conventional corn (Zea mays L.)-soybean (Glycine max L.) system from 1993 to 2003 with fertilizer application and tillage prior to planting in the spring. A precision agriculture system defined by two main management zones was implemented from 2004 to 2014: Wheat (Triticum aestivum L.) and soybean in 60% of the field, and corn and soybean in the remaining 40%. The system included no-till, cover crops, atrazine split-applications based on weed pressure, variable rates of nitrogen (N), and variable rates of fall-applied phosphorus (P). The objective of this study was to compare runoff water quality from the two management systems, based on flow and load duration curves, cumulative distribution functions, and conclusions from replicated plot studies. The precision agriculture system did not affect annual runoff, but it did increase the frequency of low flows. Sediment losses were reduced by 87% as a result of no-till and cover crops. Atrazine and P losses were lower than expected, despite the lack of incorporation into the soil. Atrazine losses were possibly lower because of the wheat area acting as a buffer, greater atrazine adsorption and retention in the field, and faster decay. Dissolved P losses as a fraction of applied remained the same, likely because of greater adsorption and lower runoff risk when applying P. Finally, nitrate-N (NO3-N) losses decreased and resulted in an overall decrease of N losses despite a slight increase of ammonium-N (NH4-N) losses. Explanations includeincluded a greater soil water content, a different timing of N applications, and N uptake by cover crops. Building on these successes, an aspirational management system is proposed to further improve on the performance and practicality of the precision agriculture system