Physical Sciences and Mathematics Commons^™

The Nebraska Natural Heritage Program: Two Year Progress Report, Mary Clausen, Mike Fritz, Gerry Steinauer

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

Since European settlement, human activities have totally eliminated the natural vegetation from approximately 50 percent of Nebraska’s landscape, and of that remaining most has been heavily impacted. As a result, numerous plants and animals have been extirpated from the state and many others are threatened.

The destruction of Nebraska’s natural diversity resulted in both public and private conservation groups recognizing the need for a centralized and accessible biological database for the state’s rare species and natural community types. Toward this end, the Nebraska Natural Heritage Program (NENHP) was established in August, 1987 through a cooperative effort between The Nature Conservancy …

Hypoxia In The Lower Rappahannock Estuary, Albert Y. Kuo, Mohamed Z. Moustafa

Reports

There are several objectives to this study. The immediate objective is to collect a comprehensive and consistent set of field observations to better describe the hypoxic condition in the Rappahannock River. Other objectives can be classified as short and long term goals.

Long term: (1) Identify and quantify the processes contributing to the dissolved oxygen budget in deep waters, and explain the variabilities among the three Virginia major tributary estuaries. (2) Provide information for resource management so that the James River can be protected from hypoxic problems and, perhaps, the problems in the York and Rappahannock Rivers can be alleviated. …

Microbial Competition In The Biodegradation Of Phenol, Mary Ellen Frank

Theses

Three phenol degraders were isolated from the mixed liquor of the Livingston, NJ municipal treatment plant. Shaker flask experiments using one of the degraders (a Pseudomonas sp.) resulted in the determination of its kinetic rate constants. The second phenol degrader (a Xanthamonas) lost its phenol degrading ability while being stored, and its kinetic rate constants could not be determined. The third phenol degrader (a Pseudomonas cepacia) formed flocs which interfered with the spectrophotometric determination of biomass and therefore its kinetic rate constants also could not be determined.

Mixed culture experiments were carried out using a the Pseudomonas sp. and a …

Thermal Desorption Of Hazardous And Toxic Organic Compounds, Manuel S. Nolau

Theses

The purpose of this thesis is to study the thermal desorption behavior of toxic organic compounds, specifically o-xylene, p-xylene, ethyl benzene, p-chlorotoluene, and anthracene, from soil with respect to temperature and time, and to develop a mathematical model that will describe this desorption behavior. The model will allow prediction of the concentration of an organic contaminant in commercial soil desorption system over time given a known set of parameters of the specific chemical as well as flow rate and temperature. For this purpose, two sets of experiments were done: These are identified as 1. Thermal desorption and 2. plug flow …

Study Of An Analytical Method For Benzo(A)Pyrene Metabolites In Human Urine, Zheng Ouyang

Theses

A method developed by Becher and Bjorseth for analysis of PAH metabolites in urine was employed to investigate human exposure to benzo(a)pyrene (BaP) - an ubiquitous environmental carcinogen. Preliminary results are presented showing the relationship between exposure to BaP and urinary elimination. Although the correlation between the two variables is not statistically significant, there appears to be a positive association with selected exposure varibles such as smoking. The identification of an association may establish urinary BaP as a marker of exposure.

However, detailed study of the analytical procedure indicated that recoveries with this method were as low as 3-8% for …

Toxicokinetics And Toxicodynamics Of Pyrethroid Insecticides In Fish, Steven P. Bradbury, Joel R. Coats

Steven P. Bradbury

The pyrethroid insecticides are extremely toxic to fish, with 96—h LC50 values generally below 10 μg/L and i.p. and i.v. LD50 values below 20 mg/kg. Corresponding LD50 values in mammals and birds are in the range of several hundred to several thousand milligrams per kilogram. This review examines pyrethroid toxicokinetics and toxicodynamics in fish as critical factors associated with species selectivity. Studies with permethrin, cypermethrin and fenvalerate have established that rates of metabolism and elimination in rainbow trout are significantly lower than those reported for birds and mammals. Comparatively low lethal brain pyrethroid concentrations and nonneural aspects of pyrethroid intoxication …

The Prairie Naturalist Volume 21, No.2 June 1989

The Prairie Naturalist

THE MISSISSIPPI KITE IN THE ENVIRONMENTAL HISTORY OF THE SOUTHERN GREAT PLAINS ▪ E. G. Bolen and D. L. Flores

TAPE-RECORDED CHICK CALLS TO LOCATE GRAY PARTRIDGE NESTS ▪ J. P. Carroll

BORROW DISTRIBUTION OF THE THIRTEEN-LINED GROUND SQUIRREL IN GRAZED MIXED-GRASS PRAIRIE: EFFECT OF ARTIFICIAL HABITAT STRUCTURE ▪ D. W. Kaufman and G. A. Kaufman

PIPING PLOVERS NESTING AT NELSON RESERVOIR, MONTANA ▪ D. W. Prellwitz, T. A. Prellwitz, K. L. Stutzman, and J. W. Stutzman

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA - 1988 ▪ R. N. Randall

CHANGING HABITATS IN THE PLATTE RIVER VALLEY OF NEBRASKA ▪ J. …

Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Root exploitation of enriched soil microsites was examined for the tussock grasses Agropyron desertorum and Agropyron spicatum and the shrub Artemisia tridentata. Two mechanisms of exploitation of the microsites were examined: root proliferation and changes in nutrient uptake capacity. One day after nutrient solution was applied to small soil patches, the mean relative growth rate of Agropyron desertorum roots in enriched patches was two to four times greater than for roots of the same plants in soil patches treated with distilled water. This rapid and striking root proliferation occurred in response to N-P-K enrichment as well as to P or …

Management, Foraging Behavior, Diet Composition And Forage Quality Of Free-Ranging But Herded Camels In Ceeldheer District, Central Somalia, Ahmed A. Elmi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In Somalia, camel (Camelus dromedarius) survivability and milk production has been higher than for other domestic livestock and contributes substantially to the subsistence of Somali pastoralists. The objective of this research was to study management, foraging behavior and nutrition of camels in their natural habitat to determine how production continues under seasonal nutritional stress.

Management systems of Ceeldheer pastoralists are based on available natural pasture and water. The natural rotation grazing system maintained an ecological equilibrium in the District.

Pastoralists manipulate their herds to suit existing environmental conditions, family needs and labor availability for herding. In herd management, …

A Study Of Denitrosation Of N-Nitroso Compounds By Irradiation With Long-Wavelength Uv Light, Zhenyu J. Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

N-Nitrosamines and N-nitrosamides have been reported to be mutagenic. N-Nitrosamides are direct mutagens that need no activation to be mutagenic, whereas N-nitrosamines need to be enzymatically activated to exert their mutagenicity. Oxidative demethylation of nitrosamines is a commonly accepted activation mechanism. Another pathway of nitroso compounds, denitrosation, has recently been proposed. The mechanism of denitrosation, however, is still unknown.

The purpose of this study was to use a photo -reaction model to explore the possible denitrosation mechanism of N-nitroso compounds. An N-nitrosamine, N-nitrosomorpholi ne (NMOR), and an N-nitrosamide, N-methyl-N'-nitrosoguanidine (MMNG), were irradiated with long-wavelength UV light in the presence of …

Determination Of Marina Buffer Zones Using Simple Mixing And Transport Models : A Report To The Virginia State Dept. Of Health, Bureau Of Shellfish Sanitation As Part Of The Chesapeake Bay Initiatives Marine Pollution Abatement Initiative, John M. Hamrick, Bruce J. Neilson

Reports

This report describes the rationale, development and application of simple mixing and transport models for the determination of marina buffer zones and buffer zones for other point source discharges. Included in the report are two computer programs for implementation of the most general two dimensional transport model.

Modeling Forest Dynamics Based On Stand Level Resource Allocation, Geoffrey Candler Poole

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An ecologically based model of forest succession is presented. In the model, trees compete for a share of limited growth resources available from their environment. Competition is reflected by each tree's effect on the resource pool and is not explicitly modeled. Model parameters were fit to field data from subalpine forests of the Rocky Mountains. A technique for estimating model parameters from understory-tolerance rankings and silvical characteristics of each species is also presented. The model's output was consistent with our current understanding of forest dynamics. Emergent properties of the model also mimicked natural processes such as self-thinning, release, and maximum …

Using Computer Imaging To Assess Visual Impacts Of Forest Insect And Disease Pests, Daniel Rabin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest insect and disease pests alter the appearance of trees, thereby impacting visual resources. Because of the complexity of most forest landscapes, the degree of visual impact of pest-infested forest stands is difficult to quantify.

This paper describes a method of measuring visual impacts of pest-infested forest stands. Photographs of healthy Ponderosa pine trees were entered into a computer video-image-processing system. Using this system, images of trees were altered to simulate different degrees of infestation by limb rust, a forest pathogen.

The altered and unaltered images were shown to groups of observers who rated the scenes in terms of "scenic …

Using Interaction In Two-Way Data Tables, Hugh G. Gauch Jr., Richard W. Zobel

Conference on Applied Statistics in Agriculture

Agronomists and breeders frequently collect yield data for a number of genotypes in a number of environments (site-years), resulting in a two-way data table. The Additive Main effects and Multiplicative Interaction (AMMI) model combines regular analysis of variance (ANOVA) for additive main effects with principal components analysis (PCA) for multiplicative structure within the interaction (that is, within the residual from ANOVA). AMMI is effective for (1) understanding genotype-environment interaction, (2) improving the accuracy of yield estimates, (3) increasing the probability of successfully selecting genotypes with the highest yields, (4) imputing missing data, and (5) increasing the flexibility and efficiency of …

The Analysis Of The Additive Mixed Model For Classes Of Non Orthogonal Designs, Christine A. Stidley

Conference on Applied Statistics in Agriculture

Tests for fixed and random effects can be difficult to derive for nonorthogonal designs with mixed models. However, extensions of the intrablock and inter-block analyses of Balanced Incomplete Block Designs can often be obtained. Here we derive the extensions for the broad class of Group Divisible Designs. Decompositions of the design space are used to develop exact tests for fixed and random effects in the additive mixed model with random block effects. Conditions on the design which permit the standard use of the intra-block and inter-block test statistics are given. Important subclasses of Group Divisible Designs include Equireplicate Variance Balanced …

A Combined Analysis Of Experiments When Treatments Differ Among Experiments, Paul N. Hinz, Mario R. Pareja

Conference on Applied Statistics in Agriculture

The advantages of repeating experiments in several locations and years are discussed and standard methods of analysis are reviewed. The methods assume that the same treatments are used in each experiment. This paper discusses a method used for a combined analysis when the treatments represent levels of a quantitative factor but differ among experiments. The method makes use of multiple regression analysis in which a continuous variable represents treatment levels, classification variables represent experiments, and products of the continuous and classification variables represent differences among experiments. The method is illustrated on data from a series of experiments designed to study …

Evaluating The Effect Of Commodity Donation Programs Using The Truncated Normal Distribution, J. William Levedahl

Conference on Applied Statistics in Agriculture

The magnitude of both the displacement of commercial sales and the increase in consumption associated with a commodity distribution program are characterized using the truncated normal distribution. This method is easier to implement and requires less data than previous methods. It is applied to data from the 1986 Survey of TEFAP Recipients and is quite accurate.

Forecasting Corn Ear Weight Using Surface Area And Volume Measurements: A Preliminary Report, Fatu Bigsby

Conference on Applied Statistics in Agriculture

Data from the Corn Ear Weight Study were used to analyze the forecast performance of models estimated using surface area and volune measurements to predict corn ear weight. Two models based on research measurements were compared to models estimated using the operational procedures from the Corn Objective Yield Survey. Research and operational models were estimated both within and across years using data from the 1986 and 1987 Michigan Corn Ear Weight Study. Results show that research models based on surface area and volune measurements have mean square errors that are 32 to 52 percent lower than models estimated using the …

Forecasting Corn Ear Weights From Daily Weather Data, Fred B. Warren

Conference on Applied Statistics in Agriculture

Statistical models were developed to predict the State average grain weight per ear using daily temperature and precipitation data, recorded from May 1 through late July. The required daily weather data was successfully obtained in an operational test of these models for ten major corn producing States in 1988. Relative forecast errors of ear weight averaged almost one-third smaller than those from a regular survey. Additional refinements of the models to make them more responsive to abnormally early adverse weather, as in 1988, are underway.

Kansas Wheat Objective Yield Survey, Eldon J. Thiessen

Conference on Applied Statistics in Agriculture

In response to farmers, millers, and government needs, the USDA began research on objective measurements of wheat yields in 1938. USDA's current objective yield program providing monthly pre-harvest forecasts of wheat production beginning on May 1 now includes 18 states and accounted for 87 percent of the U.S. wheat production in 1988 .

The Wheat Objective Yield Survey is a systematic subsample of the March Agricultural Survey conducted by Kansas Agricultural Statistics as part of the Quarterly Agricultural Survey program of the National Agricultural Statistics Service (NASS). The fields and sample plots within the fields are selected following very carefully …

Model Building To Measure Impact Of Weather On Crop Yields, Arlin M. Feyerherm, Gary M. Paulsen

Conference on Applied Statistics in Agriculture

The object of this research was to identify and evaluate alternatives when building mathematical models to measure the impact of weather on crop yields. Alternatives exist relative to selection of: (1) observational units with attention to size and coverage (areal and temporal), (2) observational periods for defining weather variables, and (3) mathematical forms and types of weather variables to measure impacts of moisture and temperature. The study involved an analysis of four weather-yield functions for winter wheat. The functions represented combinations of levels of two factors: (1) size and coverage of the observational units (plot yields from a multi-state area …

Teaching Statistical Methods To Graduate Students In Colleges Of Agriculture, D. F. Cox

Conference on Applied Statistics in Agriculture

One method of judging the effectiveness of the teaching of statistical methods is to rate the quality of their use in the research journals of the agricultural sciences. A conclusion that improvement is possible is easily supported by such a review. Basic concepts such as the meaning of replication, the definition of an experimental unit and the nature of experimental error are misunderstood, and this leads to faulty analyses and incorrect conclusions. Changes in teaching that would improve the product are not specified easily because research on the topic is difficult. Perhaps more emphasis on the basic concepts of experimental …

Evaluation Of Presentation Graphics For The Agricultural Sciences, Kathy Shelley

Conference on Applied Statistics in Agriculture

Professional-looking text and graphic slides enable an audience to comprehend the main ideas of a presentation more quickly. With the advent of easy-to-use graphic software packages and the affordability of personal computer hardware to run this software, researchers may now prepare their own slides or transparencies. This paper describes basic graphic software design and offers criteria for selection of an appropriate software package for scientific research presentations. Comparisons between two prototype graphics packages, Harvard Graphics and SAS/Graph, are made on the basis of the following selection criteria: (1) basic software design, (2) available hardware, (3) output device drivers, (4) available …

The 2-Sprt As An Alternative To Wald's Sprt When Testing Hypotheses Concerning Insect Populations, Linda J. Young, Jerry H. Young

Conference on Applied Statistics in Agriculture

Exact and Wald's approximations for the operating characteristic and average sample number functions are compared for a sequential probability ratio (SPRT) test commonly used in cotton integrated pest management (IPM) programs in southwestern Oklahoma. The 95th percentile of the sample size is also given. For the same set of hypotheses and stated error probabilities, the exact operating characteristic and average sample number functions and the 95th percentile of sample size are compared for the SPRT and 2-SPRT.

Multiple Regression Analysis Of Soil Properties On Eroded And Native Deep Loess Missouri Soils, S. J. Indorante, J. M. Maatta, R. D. Hammer, J. R. Brown

Conference on Applied Statistics in Agriculture

Researchers have described the difficulty of studying the effects of cultivation on soil properties unless native (uncultivated) areas can be used as a baseline for comparison. Even when suitable areas are located the problems of quantifying and comparing the horizontal and vertical distributions of soil properties remain. Areal distributions of soil surface, subsurface, and upper subsoil properties were compared in cultivated and forested deep loess soils on similar geomorphic surfaces and hillslope positions in two counties adjacent to the Missouri River. A 3-dimensional grid was used to sample selected soils from the summit to the lower backs lope on 3 …

Evaluation Of The Three Plantain (Musa Aab) Cultivars For Agronomic Characteristics, Ahmad R. Rafie, Carlos Medina

Conference on Applied Statistics in Agriculture

Plantains (Musa AAB) are widely used as a source of carbohydrate in Latin America and Africa. The most commonly grown plantain cultivar, "Horn plantain" is tall which makes it susceptible to losses by wind. Recently, two dwarf mutants of "Horn plantain" were selected. A randomized complete block design experiment with four replications was conducted to compare the agronomic characteristics of the dwarf mutants with those of the traditional cultivar. The data was analyzed as if the experiment was strip-plot design with cultivar as the horizontal factor and harvest as the vertical factor. "Analysis of variance" and "Least significant difference" test …

Comparison Of Hop Downy Mildew Epidemics Using Spatial Analysis, J. Richard Alldredge, Dennis A. Johnson, Rochelle Allwine

Conference on Applied Statistics in Agriculture

Methods of spatial analysis including distribution fitting, variance-to-mean ratios, Morisita's index, doublet and runs analyses, Greig-Smith analysis and variography were used to investigate the spatial pattern of hop downy mildew. Use of these methods allowed examination of the spatial structure of hop downy mildew at three spatial scales: within hop hills, between nearby hop hills, and for hop hills more separated in space. The results obtained were in general agreement for methods of analysis which assessed spatial structure at the same spatial scale with the exception of Morisita's index of clumping which did not identify clumps of diseased hills of …

The Use Of Near Infrared Reflectance For Evaluating Cotton Fineness And Maturity, Vicki A. Lancaster, Steven M. Buco, Joseph G. Montalvo Jr.

Conference on Applied Statistics in Agriculture

The U.S. Department of Agriculture has proposed to develop Ii new high speed, high volume technique to assess cotton quality. This goal has led us to investigate the feasibility of near infrared reflectance spectroscopy as a technique for evaluating cotton fiber perimeter size and wall thickness, two of the physical characteristics used in the evaluation of cotton fineness and maturity.

In order to isolate the effects of perimeter size and wall thickness, nineteen cotton samples were selected on the basis of their having a nonsignificant correlation between these 2 measurements. The reflectance spectra from 1100 to 2500 nanometers was recorded …

Statistical Design And Analysis Of Dairy Nutrition Experiments To Improve Detection Of Milk Response Differences, Stephen R. Lowry

Conference on Applied Statistics in Agriculture

The objective of many dairy nutrition experiments is to determine the effect of certain dietary treatments on milk production and quality responses. However, milk responses are quite variable and cows (experimental units) are expensive and have substantial maintenance costs. This manuscript reviews principles for planning to obtain good data relevant to the hypothesis, experimental design to control inherent variation, and interpreted analyses to facilitate understanding of dairy relationships. Emphasis is placed on assurance that milk response differences due to dietary treatments will have a high probability of being detected as significant. Guidelines addressing these principles along with suggested computer programs …

Statistical Models For Analysis Of Dose-Response Data, Karan P. Singh

Conference on Applied Statistics in Agriculture

In this paper we propose three families of functional models for analysis of dose-response data. The first family is for modeling data which have a steep sloping line for an ascending portion of the response curve and a plateau representing maximum response or a sloping line representing little response at higher application levels. The second family is for modeling data which represent a steep sloping line on the ascending portion of the response curve and a declining curvature for declining response at higher application levels. The third family is for fitting data which show an initial plateau followed by increased …