Physical Sciences and Mathematics Commons^™

Prioritization Of Scientific Sources Of Water Information: The Effect Knowledge, Beliefs, And Political Identity, Sadie Hundemer

Journal of Applied Communications

Scientists are reported to be more trusted than other information sources; yet, on essential water facts, people sometimes reject what they perceive water scientists to believe in favor of other belief determinants. This study examines the factors that affect the difference in people's stated willingness to reconsider their water beliefs in response to information provided by scientists relative to information provided by other sources. Regression analysis of responses provided by 806 Florida and Georgia residents found water science knowledge to be a consistently strong influencer of the gap in reliance on scientific information providers relative to other sources. This result …

Soils Laboratory Manual: K-State Edition, Version 2.0, Colby J. Moorberg, David A. Crouse

NPP eBooks

The Soils Laboratory Manual, K-State Edition is designed for students in undergraduate, introductory soil science courses. The manual highlights the multidisciplinary aspects of soil science with laboratories focused on soil formation, classification, and mapping; soil physics, soil biology; soil chemistry; and soil fertility and management. The lab manual includes 16 different laboratories, each one starting with an introduction and pre-lab assignment, followed by in-lab activities, and complimented by a post-lab assignment. In-lab activities involve field trips, experiments, observation stations, or problem sets. Post-lab assignments include online quizzes, problem sets, or laboratory summary reports.

Version 2 of the lab manual exhibits …

Soil And Water Conservation: An Annotated Bibliography, Colby J. Moorberg

NPP eBooks

Soil and Water Conservation: An Annotated Bibliography highlights freely-available online resources covering various aspects of soil and water conservation, and is designed to be a resource for conservation students and practitioners. The thirteen chapters in the annotated bibliography are grouped into four sections, including History and Fundamentals, Conservation Practices, Conservation Implementation, and Careers. Types of cited resources include extension bulletins, USDA NRCS conservation practice standards, and other government reports and resources. Cited resources are generally concise, easily read, and meant for general audiences. Annotations and images are used to provide context for each resource. Many contributors made Soil and Water …

Preface, Weixing Song

Conference on Applied Statistics in Agriculture

Preface

Exploring Multi-Year Soybean Yield Trial Data In South Dakota Environments, Jixiang Wu, Jianli Qi, Jonathan Kleinjan

Conference on Applied Statistics in Agriculture

Crop performance test (CPT) is a common practice to evaluate yield performance and adaptability of each cultivar. In this study, we combined 16 years of soybean CPT data, which included six representative locations, three major maturity groups, and over 1000 cultivars, to determine some patterns associated with yield production. As expected, the repeatability for these cultivars in trial over years was very low. Thus, the data processing in this study was focused on descriptive statistics regarding time, location, and seed supplier and several linear model analyses. The results will be presented during the conference.

Modeling Potato Psyllid Occurrence Using Sticky Trap Data For The Management Of Zebra Chip Disease, William J. Price, Erik J. Wenninger, Bahman Shafii Ph.D.

Conference on Applied Statistics in Agriculture

Zebra chip disease (ZC) is a disease of potato which produces striped necrotic patterns that become pronounced when fried, making potato products such as chips and fries unmarketable. The disease is associated with a bacterium Candidatus Liberibacter solanacearum (Lso) and is transmitted by the potato psyllid, Bactericera cockerelli. An important aspect in managing this disease is the modeling and prediction of potato psyllid occurrence. In this study, potato psyllid numbers were monitored regularly across the southern Idaho region. This unique data set encompasses psyllid counts, collected by multiple sticky traps, set up at 98 growing sites over the growing …

Evaluating Adaptions Of Soft Red Winter Wheat In Eastern Region Of Usa, Dilmini Alahakoon, Anne Fennell, Jixiang Wu

Conference on Applied Statistics in Agriculture

Identification of winter wheat cultivars that are highly adapted to a wide range of environmental conditions is one of the most important wheat research objectives. Multi-environment crop trials under diverse environments is a commonly used practice to evaluate yield stability. For example, uniform eastern and southern red soft winter wheat nursery trials are conducted annually. However, locations and cultivars may vary from year to year and may cause yield stability analysis to be statistically challenging. In this study, we evaluated cultivars that were widely adapted to eastern production areas and those that were specifically adapted to other environments. We used …

Simulation Comparison Of Methods To Estimate Confidence Intervals Of The Mitigated Fraction, Kenneth W. Wakeland, Brian Fergen

Conference on Applied Statistics in Agriculture

In the area of veterinary medicine, efficacy studies are conducted to support licensure of vaccines. Such studies are typically designed to assess a vaccine's ability to prevent or mitigate clinical disease. For example, reduction of duration/severity of clinical signs or the severity of lung lesions are often considered as primary or secondary criteria of success. Studies designed to measure efficacy typically utilize two or more treatment groups and often use blocking structures to accommodate animal housing or litter related effects. When the criteria of interest are continuous or ordinal variables, as is the case with the above measurements, the mitigated …

Statistical Methods For Assessing Individual Oocyte Viability Through Gene Expression Profiles, Michael O. Bishop, John R. Stevens, S. Clay Isom

Conference on Applied Statistics in Agriculture

In vivo derived oocytes are held as the gold standard for viability, other known origination methods are sub-par by comparison. Due to the low-viability of oocytes originating from these alternate methods, research was conducted to determine and quantify the validity of these alternate origination methods. However, the larger question of viability is on the individual oocyte level. We propose and compare methods of measurement based on gene expression profiles (GEPs) in order to assess oocyte viability, independent of oocyte origin. The first is based on a previously published wRMSD quantification of GEP differences. We also consider three novel methods: a …

Simulation Comparison Of Statistical Methods Used In Assessing Vaccine Efficacy In Veterinary Biologics, Kenny Wakeland, Brian Fergen

Conference on Applied Statistics in Agriculture

In veterinary biologics, clinical studies conducted to support the licensure of a vaccine generally include a demonstration of efficacy in the species of interest. Typically, these studies are designed to assess a vaccine’s ability to prevent or mitigate clinical disease. Study designs utilize two or more treatment groups, and often incorporate blocking structure restrictions to accommodate animal housing or litter-related effects. When assessing a vaccine’s ability to prevent clinical disease, the prevented fraction (PF), a function of the group proportions of affected animals, is often utilized. Typically the sample size per treatment group is limited, and each block is represented …

Topological Methods For The Quantification And Analysis Of Complex Phenotypes, Patrick S. Medina, Rebecca W. Doerge

Conference on Applied Statistics in Agriculture

Quantitative Trait Locus (QTL) mapping of complex traits, such as leaf venation or root structures, require the phenotyping and genotyping of large populations. Sufficient genotyping is accomplished with cost effective high-throughput assays, however labor costs often makes sufficient phenotyping prohibitively limited. In order to develop efficient high-throughput phenotyping platforms for complex traits algorithms and methods for quantifying these traits are needed. It is often desirable to study the spatial organization of these phenotypes from the images generated by high-throughput platforms. With the goal of quantifying the traits, many approaches try to identify several core traits useful in describing the phenotypic …

Bayesian Estimation Of Stability Indices Of Sorghum Variety Trials, Siraj Osman Omer, Abdel Wahab Hassan Abdalla, Mohammed Hamza Mohammed, International Center For Agricultural Research In The Dry Areas (Icarda), Amman, Jordan

Conference on Applied Statistics in Agriculture

Multiple–environmental trials are routinely conducted by crop improvement programs for developing desired genotypes. Over a long run, these programs gather information on genotypic performance and variability. Bayesian approach can be used to utilize prior information to identify genotypes for high and stable yield. A set of 18 sorghum genotypes were evaluated in randomized complete block designs (RCBD) with four replications during three seasons, 2009-2012 at diverse locations, North-Gedarif and South-Gedarif, in Sudan. Data on grain yield was analyzed. The aim of this paper was to estimate stability indices such as regression coefficient, coefficient of variation (CV %) and coefficient of …

Strategies For Reducing Control Group Size In Experiments Using Live Animals, Matthew Kramer, Enrique Font

Conference on Applied Statistics in Agriculture

Reducing the number of animal subjects used in biomedical experiments is desirable for both ethical and practical reasons. Previous suggestions for reducing sample sizes in these experiments have focused on improving experimental designs and methods of statistical analysis; reducing the number of controls (thus, the number of overall animals used) is rarely mentioned. We discuss how the number of current control animals can be reduced, without loss of statistical power, by incorporating information from historical controls, i.e. animals used as controls in similar previous experiments. Using example data from the literature, we describe how to incorporate information from historical controls …

Alternative Estimation Techniques For Correlated Discrete Data, William J. Price Ph.D., Bahman Shafii Ph.D.

Conference on Applied Statistics in Agriculture

Binary or multinomial data often occur in agricultural and biological research. Advancements in measurement and video technologies now allow such data to be sequentially recorded through time or space. These data sets, however, can exhibit a serial correlation structure, which in turn, can bias and influence point estimates as well as inferences made regarding the data. Statistical methods using generalized mixed models and probability distributions such as the beta-binomial and correlated binomial have been proposed as potential solutions for estimating the parameters of interest in these cases. In this paper, we will explore the properties of these techniques through simulation …

Developing Prediction Equations For Fat Free Lean In The Presence Of An Unknown Amount Of Proportional Measurement Error, Zachary J. Hass, Bruce A. Craig, Allan Schinckel

Conference on Applied Statistics in Agriculture

Published prediction equations for fat-free lean mass are widely used by producers for carcass evaluation. These regression equations are commonly derived under the assumption that the predictors are measured without error. In practice, however, it is known that some predictors, such as backfat and loin muscle depth, are measured imperfectly with variance that is proportional to the mean. Failure to account for these measurement errors will cause bias in the estimated equation. In this paper, we describe an empirical Bayes approach, using technical replicates, to accurately estimate the regression relationship in the presence of proportional measurement error. We demonstrate, via …

Paired Competition Analysis Using Mixed Models, Patrick Gallagher, Bruce A. Craig, Tim Luttermoser, Grzegorz Buczkowski

Conference on Applied Statistics in Agriculture

Urban and rural colonies of odorous house ants (Tapinoma sessile) have very different social structures. Urban colonies are very large with hundreds of cohabiting queens, while rural colonies are small with only one queen. To investigate whether worker ant aggressiveness varies across these two colony types, an experiment was performed using an aggression assay, in which 50 ants from each of two colonies were placed in a petri dish and allowed to fight. The response was the total number of dead ants within 24 hours. Because the ants were all the same species and not marked by colony, …

Irrigated And Rainfed Crops Zea Mays L. (Maize) And Glycine Max (Soybean) Acting As A Source Or Sink For Atmospheric Warming At Mead, Nebraska, Jane A. Okalebo Dr., Kenneth G. Hubbard, Andy Suyker

Conference on Applied Statistics in Agriculture

Land Use and Land Cover Change (LULCC) influence the climate at a global and local scale. Using long term microclimate data (2002-2009, 2011-2012) from the Carbon Sequestration Project (CSP), Mead, NE, this study examines how crop selection and water management can mitigate heat in the atmosphere. Mitigation of global warming is dependent on the management of crop lands, and the amount and timing of rainfall during the growing season. Rainfed crops were found to heat the passing air. The irrigated maize crop was able to mitigate 20 to 62% of the sensible heat (H) compared to the rainfed maize counterpart, …

Should Blocks Be Fixed Or Random?, Philip Dixon

Conference on Applied Statistics in Agriculture

Many studies include some form of blocking in the study design. Block effects are rarely of intrinsic interest; instead they are included in a model so that that model reflects the study design. I consider the question of how these block effects should be modeled: as fixed effects or as random effects. I discuss the consequences of the choice, including the recovery of inter-block information when available, give a simple example to illustrate the connection between recovery of inter-block information and pooling two estimators of a treatment effect, and give an example where fitting a model with random block effects …

Comparing Linear Mixed Models For Preliminary Yield Trials That Follow Augmented Experimental Designs, Sudha Neupane Adhikari, Jixiang Wu, Melanie Caffe

Conference on Applied Statistics in Agriculture

COMPARING LINEAR MIXED MODELS FOR PRELIMINARY YIELD TRIALS THAT FOLLOW AUGMENTED EXPERIMENTAL DESIGNS

Sudha Neupane Adhikari, Jixiang Wu, and Melanie Caffe-Treml

Agronomy, Horticulture, and Plant Science Department,

South Dakota State University, Brookings, SD 57007

Abstract

Ineffective control of spatial variation when analyzing field trials data may lead to biased conclusions, which in turn could impact selection efficiency in plant breeding programs. In this study, a group of 78 oats breeding lines were evaluated in preliminary yield trials at four locations in South Dakota in 2015. Four linear mixed models (with and without row and column effects) were compared regarding reduction …

A Bayesian Gwas Method Utilizing Haplotype Clusters For A Composite Breed Population, Danielle F. Wilson-Wells, Stephen D. Kachman

Conference on Applied Statistics in Agriculture

Commercial beef cattle are often composites of multiple breeds. Current methods used to produce genomic predictors are based on the underlying assumption of animals being sampled from a homogeneous population. As a result, the predictors can perform poorly when used to predict the relative genetic merit of animals whose breed composition are different. In part, this is due to the changes in linkage disequilibrium between the markers and the quantitative trait loci as we move from one breed to the next. An alternative model based on breed specific haplotype clusters was developed to allow for differences in linkage disequilibrium across …

Editor's Preface And Table Of Contents, Perla Reyes

Conference on Applied Statistics in Agriculture

2016 Conference on Applied Statistics in Agriculture Proceedings

Using A Generalized Linear Mixed Model Framework To Account For Spatial Variability In A Comparison Of Orchard Sprayer Efficacy, William J. Price, Bahman Shafii, Don Morishita

Conference on Applied Statistics in Agriculture

Uniform application of pesticides in vineyard and orchard systems can be difficult to achieve due to variability in the density and structure of the crop canopy. Depending on the equipment used and environmental conditions, applications can result in poor spray coverage, spray drift, and wasted spray which, in turn, are manifested as a combination of poor pesticide efficacy, economic losses and potential environmental problems for the grower. A study was therefore designed and carried out to test new sprayer equipment aimed at addressing these issues. Statistically, the study presented a unique replicated three dimensional spatial design which captured response variability …

Statistical Methods In Topological Data Analysis For Complex, High-Dimensional Data, Patrick S. Medina, R W. Doerge

Conference on Applied Statistics in Agriculture

The utilization of statistical methods an their applications within the new field of study known as Topological Data Analysis has has tremendous potential for broadening our exploration and understanding of complex, high-dimensional data spaces. This paper provides an introductory overview of the mathematical underpinnings of Topological Data Analysis, the workflow to convert samples of data to topological summary statistics, and some of the statistical methods developed for performing inference on these topological summary statistics. The intention of this non-technical overview is to motivate statisticians who are interested in learning more about the subject.

Best Linear Unbiased Prediction: An Illustration Based On, But Not Limited To, Shelf Life Estimation, Maryna Ptukhina, Walter Stroup

Conference on Applied Statistics in Agriculture

Shelf life estimation procedures, following ICH guidelines, use multiple batch regression with fixed batch effects. This guidance specifically mandates estimates based on at least 3 batches. Technically, the fixed-batch model limits inference to the batches actually observed, whereas ICH requires resulting estimates to apply to all future batches stored under similar conditions. This creates a conflict between the model used and the inference space the model is intended to address. Quinlan, et al. (2013) and Schwenke (2010) studied the small sample behavior of this procedure. Both studies revealed large sampling variation associated with the ICH procedure, producing a substantial proportion …

Shiga Toxin-Producing Escherichia Coli In Meat: A Preliminary Simulation Study On Detection Capabilities For Three Sampling Methods, Julie Couton, David Marx, John Luchaansky, Randall Phebus, Anna Porto-Fett, Nicholas Sevart, Manpreet Singh, Harshavardhan Thippareddi

Conference on Applied Statistics in Agriculture

Contamination by Shiga Toxin-producing Escherichia coli (STEC) is a continuing concern for meat production facility management throughout the United States. Several methods have been used to detect STEC during meat processing, however the excessive experimental cost of determining the optimal method is rarely feasible. The objective of this preliminary simulation study is to determine which sampling method (Cozzini core sampler, core drill shaving, and N-60 surface excision) will better detect STEC at varying levels of contamination present in the meat. 1000 simulated experiments were studied using a binary model for rare occurrences to find the optimal method. We found that …

Differential Methylation Methods In Multi-Context Organisms, Douglas Baumann, Yuqing Su, Iranga Mendis, Gayla R. Olbricht

Conference on Applied Statistics in Agriculture

DNA methylation is an epigenetic modification that has the ability to alter gene expression without any change in the DNA sequence. DNA methylation occurs when a methyl chemical group attaches to cytosine bases on the DNA sequence. In mammals, DNA methylation primarily occurs at CG sites, when a cytosine is followed by a guanine in the DNA sequence. In plants, DNA methylation can also occur in other cytosine sequences, such as when a cytosine is not followed directly by a guanine. Many of the statistical methods that have been developed to estimate methylation levels and test differential methylation in whole-genome …

On Fixed Effects Estimation In Spline-Based Semiparametric Regression For Spatial Data, Guilherme Ludwig, Jun Zhu, Chun-Shu Chen

Conference on Applied Statistics in Agriculture

Spline surfaces are often used to capture spatial variability sources in linear mixed-effects models, without imposing a parametric covariance structure on the random effects. However, including a spline component in a semiparametric model may change the estimated regression coefficients, a problem analogous to spatial confounding in spatially correlated random effects. Our research aims to investigate such effects in spline-based semiparametric regression for spatial data. We discuss estimators' behavior under the traditional spatial linear regression, how the estimates change in spatial confounding-like situations, and how selecting a proper tuning parameter for the spline can help reduce bias.

Small Sample Properties Of The Two Independent Sample Test For Means From Beta Distributions, Edward E. Gbur, Kevin Thompson

Conference on Applied Statistics in Agriculture

Researchers often collect proportion data that cannot be interpreted as arising from a set of Bernoulli trials. Analyses based on the beta distribution may be appropriate for such data. The SAS® GLIMMIX procedure provides a tool for these analyses using a likelihood based approach within the larger context of generalized linear mixed models (GLMM). The small sample behavior of likelihood based tests to compare the means from two independently sampled beta distributions were studied via simulation when the null hypothesis of equal means holds. Two simulation scenarios were defined by equal and unequal sample sizes and equal scale parameters. A …

Modeling The Occurrence Of Four Cereal Crop Aphid Species In Idaho, John W. Merickel, Bahman Shafii, Sanford D. Eigenbrode, Christopher J. Williams, William J. Price

Conference on Applied Statistics in Agriculture

Idaho is ranked 5^th in the United States in overall wheat production and makes over $500 million in profit annually from wheat. Many pests have detrimental effects on wheat; some of the most predominant ones are aphids. Four species of aphids having economic effects on wheat crops in Idaho are: Diuraphis noxia, Metopolophium dirhodum, Rhopalosiphum padi, Sitobion avenae. Predictive regression models could be useful for better understanding of the occurrence of these aphid species. Count data for the four species were collected over 17 years via suction traps at 12 locations in wheat fields throughout …

Editor's Preface And Table Of Contents, Perla E. Reyes

Conference on Applied Statistics in Agriculture

These proceedings contain papers presented at the twenty-seventh annual Kansas State University Conference on Applied Statistics in Agriculture, held in Manhattan, Kansas, April 26 - April 28, 2015