Quantification of Pollutants in Surface Runoff From Agricultural Lands in Brookings County, South Dakota

Surface runoff from snowmelt and rainfall was measured 1n eastern South Dakota from seven sites (7.18 to 18.69 acres) during 1971 and 1972. All sites had single crops which included corn, oats, pasture and hayland. All land was farmed under normal farming conditions. Samples were taken periodically throughout each runoff event, and a single composite sample was made from the individual samples for a particular site. The composite sample represented the entire runoff event. The amount of rainfall and the runoff flow were measured. Determinations on the composite sample included total coliform, fecal coliform, fecal streptococcus, soluble pesticides, specific conductance, raw and soluble chemical oxygen demand, raw and soluble total kjeldahl nitrogen, raw and soluble total phosphorus, suspended solids, total residue and nitrates. In addition, ammonia-nitrogen was determined for some samples; and when possible, pesticide determinations were made on mud samples. Runoff samples from 91 snowmelt events and 32 rainfall events were collected over the two year period. The first year represented a season of below normal precipitation and the second year was a year of above average precipitation. Sediment losses were considerably below losses predicted by the universal soil-loss equation. This was attributed to differences in runoff plot size and local hydrologic conditions. Most of the sediment lost was from the cultivated fields and only small amounts washed off fields in permanent grass. Host of the soil-loss happened. during short duration, highly intense summer rainstorms. Coliform and fecal coliform levels were consistently greater than accepted surface water quality criteria. The fecal coliform to fecal streptococcus ratio appears to indicate contamination from a nonhuman source, as expected. Pesticide concentrations were low in both water and sediment samples. Analyses generally showed levels below the analytical test limits. Nutrient losses ranged from 0.03 to 3.0 lb/acre/yr of nitrogen and from 0.01 to 0.72 lb/acre/yr of phosphorus. Considerable amounts of nutrients were found to be soluble and/or associated with snowmelt runoff

Selection of Executive Secretary for IAS Committee Report

For a number of years the Iowa Academy has felt a growing need for more effective promotion of science and science education in the state of Iowa. The establishment of a permanent office with a salaried executive secretary is envisioned as a major step toward the accomplishment of this goal. This committee report indicates recommended procedures for making such a move by September, 1967

The role of gender in entrepreneur-investor relationships : A signaling theory approach

Author's accepted version (postprint).Available from 11/01/2018.This is the peer reviewed version of the following article: Alsos, G. A. & Ljunggren, E. (2016). The role of gender in entrepreneur-investor relationships: A signaling theory approach. Entrepreneurship: Theory & Practice, which has been published in final form at http://dx.doi.org/10.1111/etap.12226. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving (http://olabout.wiley.com/WileyCDA/Section/id-820227.html).This study adopts a gender perspective to analyze funding decisions made by an investment fund that invests equity stakes in new ventures. Prior research has indicated that there is gender skewness in risk capital investments resulting from a combination of demand- and supply-side issues. We apply signaling theory to examine the interface between demand and supply to understand gender biases related to risk capital investments. In-depth analyses of decision documents from four investment cases show that gender plays a role in the signals that are communicated in the prefunding entrepreneur–investor relationship

Nonlinear mediation in clustered data : a nonlinear multilevel mediation model

textMediational analysis quantifies proposed causal mechanisms through which treatments act on outcomes. In the presence of clustered data, conventional multiple regression mediational methods break down, requiring the use of hierarchical linear modeling techniques. As an additional consideration, nonlinear relationships in multilevel mediation models require unique specifications that are ignored if modeled linearly. Improper specification of nonlinear relationships can lead to a consistently overestimated mediated effect. This has direct implications for inferences regarding intervention causality and efficacy. The current investigation proposes a nonlinear multilevel mediation model to account for nonlinear relationships in clustered data. A simulation study is proposed to compare the statistical performance of the proposed nonlinear multilevel mediation model with that of conventional methods.Educational Psycholog

Nonlinear mediation in clustered data : a nonlinear multilevel mediation model

textMediational analysis quantifies proposed causal mechanisms through which treatments act on outcomes. In the presence of clustered data, conventional multiple regression mediational methods break down, requiring the use of hierarchical linear modeling techniques. As an additional consideration, nonlinear relationships in multilevel mediation models require unique specifications that are ignored if modeled linearly. Improper specification of nonlinear relationships can lead to a consistently overestimated mediated effect. This has direct implications for inferences regarding intervention causality and efficacy. The current investigation examined a specific nonlinear multilevel mediation model parameterization to account for nonlinear relationships in clustered data. A simulation study was conducted to compare linear and nonlinear model specifications in the presence of truly nonlinear data. MacKinnon et al.’s (2007a) empirical-M based PRODCLIN method for estimating the confidence interval surrounding the instantaneous indirect effect was used to compare confidence interval coverage rates surrounding both the linear and nonlinear models’ estimates. Overall, the nonlinear model’s estimates were less biased, more efficient, and produced higher coverage rates than the linear model specification. For conditions containing a true value of zero for the instantaneous indirect effect, bias, efficiency, and coverage rate values were similar for the linear and nonlinear estimators. For conditions with a non-zero value for the instantaneous indirect effect, both the linear and nonlinear models were substantially biased. However, the nonlinear model was always less biased and always produced higher coverage rates than the linear model. The nonlinear model was more efficient than the linear model for all but two design conditions.Educational Psycholog

Tolls: Efficiency and Equity Issues for Inland Waterways

Transportation requires large amounts of capital in fixed facilities such as roads, tracks, or canals. Inland waterway transport is unique among modes, since it neither owns its right-of-way nor pays taxes to support its construction and maintenance. Although user charges are widely employed to recover the costs of publicly provided investments, proper theoretical foundation has not been made for their application to inland waterway transport. In this paper we shall provide this foundation focusing on efficiency of allocation of resources, on equity of taxation, and on administration simplicity of each toll scheme. Section 1 of this paper presents the criteria to be used in evaluating waterway user charges. Section 2 appraises possible alternative tolls and estimates the rates that would be needed to recover current expenditures. A combination of toll schemes (segment tolls, locking fees, and congestion tolls) are argued to be economically and politically feasible and to dominate fuel taxes and license fees. The Appendix presents an example of the benefits and costs of waterway expansion and a test of the predictive power of the queueing model.

Cost Functions for Inland Waterways Transport in the United States

Rightly or wrongly government plays an important role in the investment and operating decisions of transport firms. The Interstate Commerce Commission oversees a complicated structure of rates and a point-to-point system of operating licenses. For inland waterway transport, additional complications stem from the fact that the construction and maintenance of navigable waterways are controlled by Congress through the Army Corps of Engineers. It is necessary for Congress, the ICC, and the Army Corps of Engineers to cooperate and to pursue the national interest rather than the interest of any particular industry or company. These agencies therefore require knowledge of the underlying cost and demand functions. This paper is designed to provide some information on waterway cost functions.</p

A study of high-speed milling : final report, part II. The high-speed milling of titanium alloys : final report

http://deepblue.lib.umich.edu/bitstream/2027.42/4388/5/bab3710.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/4388/4/bab3710.0001.001.tx

A feasibility study on measuring the sharpness of surgical scalpels : final report

http://deepblue.lib.umich.edu/bitstream/2027.42/4372/5/bab4734.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/4372/4/bab4734.0001.001.tx

Optimal Capacity of Port Loading Facilities

Route changes and delays owing to such factors as adverse weather make it difficult to predict the exact arrival of ships or barges in a port. In choosing the capacity of loading facilities in a port, one must consider that there will be many times when the facilities will be unused and many times when cargo vessels must wait a substantial time before they are serviced. The choice of capacity of port facilities when arrival and service times are random is considered here. Queuing theory can be applied to determine the average waiting time for an individual cargo vessel as a function of the arrival and service distributions, the capacity of the terminal facility, and the arrival rate. To save waiting time for a vessel, the terminal capacity must be expanded. The optimal capacity of a loading facility is determined by trading off the additional capital cost of a dock against the value of the vessel time saved. Estimates are made of costs and savings incurred by investing in new facilities. The effects of seasonality in traffic and speeding the service rate are also considered.</p