Nutrient Mitigation Capacity of Low-Grade Weirs in Agricultural Drainage Ditches

Installation of low-grade weirs in agricultural drainage ditches is being evaluated as an innovative, and cost effective, management practice that decreases nutrient concentrations and loads by increasing water volume and hydraulic residence time of the ditch. Results revealed that weirs significantly increased (P = 0.029) hydraulic residence time (HRT) and ditch water volumes, leading to considerable reductions in outflow water volumes (61%). Furthermore, ditches with weirs achieved greater (P = 0.09) cumulative outflow load reductions (96%) and greater (P = 0.029) concentration reductions during the biogeochemical reduction phase of the experiment. Similarly, field research from Terrace Ditch in Yazoo County, MS yielded significant percentage concentration reductions for baseflow (53%), stormflow (63%), and load (65%). Results from the experimental approach and field scale research offer promising insight into the future of low-grade weir’s establishment as an additional best management practice in agricultural landscapes

Cascading Failures and Fundamental Uncertainty: Divergence in Financial Risk Assessment

By applying common financial risk assessment models to the network economy formalized in Delli Gatti et al. (2006), and by contextualizing both in the broader literature on complexity in economic systems, the question of convergence in economic models is addressed. Critically, a formal state condition is identified which can contribute to the emergence of periods of extreme divergence from expected conditions even in a model characterized by restrictive assumptions regarding agent choice and market structure. The strength of the impact of this state condition, here the topology of a credit network, on the dynamics of the economic system is furthermore shown to be highly dependent upon the structure of the market. The existence of such state conditions has fundamental implications for the evaluation of risk and institutional design in economic system

Graduate Recital:Kent Alexander Krause, Euphonium

Kemp Recital Hall Saturday Evening March 31, 2007 7:00p.m

Getting to the Point? Rethinking Arrows on Maps

Introduction. Maps help to form public opinion and build public morale. When the war is over, they will contribute to shaping the thought and action of those responsible for the reconstruction of a shattered world. Hence it is important in these times that the nature of the information they set forth should be well understood (Wright, 1942: 527)