Physical Sciences and Mathematics Commons^™

Growth Of Nanotubes For Probe Microscopy Tips, Jason H. Hafner, Chin Li Cheung, Charles M. Lieber

Barry Chin Li Cheung Publications

Carbon nanotubes, which have intrinsically small diameters and high aspect ratios and which buckle reversibly, make potentially ideal structures for use as tips in scanning probe microscopies, such as atomic force microscopy (AFM)^{1, 2, 3, 4}. However, the present method of mechanically attaching nanotube bundles for tip fabrication is time consuming and selects against the smallest nanotubes, limiting the quality of tips. We have developed a technique for growing individual carbon nanotube probe tips directly, with control over the orientation, by chemical vapor deposition (CVD) from the ends of silicon tips. Tips grown in this way may become …

Phase Control Of X-Ray–Atom Scattering In The Presence Of A Bichromatic Laser Field, Dejan B. Miloševíc, Anthony F. Starace

Anthony F. Starace Publications

We consider the scattering of 50 eV x-rays by hydrogen atoms in the presence of a bichromatic, linearly polarized laser field with frequencies ω and rω, where r = 2, 3, ω = 1.17 eV, and with relative phase &#; between the bichromatic laser field components. Numerical results for the differential cross-section (DCS) as a function of the number n, where nω is the energy exchanged with the laser field, are presented. For either a monochromatic laser field or a bichromatic laser field with the frequencies ω and 3ω, the integer n can only be even, while for a bichromatic …

A Short Proof That ‘Proper = Unit’, Kenneth P. Bogart, Douglas B. West

Dartmouth Scholarship

A short proof is given that the graphs with proper interval representations are the same as the graphs with unit interval representations.

The Influence Of Surface Terminal Layer And Surface Defects On The Electronic Structure Of Cmr Perovskites: La0.65A0.35Mno3 (A = Ca, Sr, Ba), Jaewu Choi, Hani Dulli, Sy-Hwang Liou, Peter A. Dowben, Marjorie Langell

Peter Dowben Publications

The electronic structure near to the Fermi level of the colossal magnetoresistance (CMR) perovskite manganite materials, La_0.65A_0.35MnO₃ (A = Ca, Sr, Ba), has been studied using both photoemission and inverse photoemission spectroscopy. The electronic structure for all three materials is very similar and consistent with an Mn–O terminal layer regardless of dopant. Small differences in the electronic structure among the materials are, however, observed. The observed band gap is not significant for La_0.65A_0.35MnO₃ and La_0.65A_0.35MnO₃ while there is a gap, about 1.5 eV, for La …

Design And Implementation Of A Natural Resource Curriculum Guide Incorporating Selected Standards Of Learning At The Elementary Level, Martha Elizabeth Thompson

Theses & Honors Papers

The state Standards of Learning tests were given in 1998 and the results showed a 37% failure rate for science at the third grade level. This thesis project was meant to develop a way to improve these scores. An internship was completed at Holiday Lake 4-H Educational Center where a natural resource curriculum guide was developed. The guide was developed using activities tested at the 4-H Center. Activities were chosen that met selected Standards of Learning. A copy of the activities has been placed in the Longwood College Library for use by both pre-service and classroom teachers.

Designing An Integrated Environment For Artificial Intelligence, Andrew B. Ritger '99

Honors Projects

The SHELLEY RESEARCH GROUP (part of the Illinois Wesleyan Intelligence Network on Knowledge -IWINK) has been in existence for several years, and has benefited immensely from various student contributors who have added such components as robotic arm control, cross platform networking, an artificially intelligent tic-tac-toe player, and an interactive teaching tool demonstrating the functionality of artificial neural networks. What is lacking, however, amidst these undergraduate contributions to the SHELLEY Project, is an effective means of integrating existing components into a single cohesive functional unit, let alone any easy means of making further contributions within a simple unified context. The focus …

The Power Of Structured Designs And Mixed Models In A Real World Experiment, J. C. Galland, G. A. Milliken, D. R. Hyatt, M. Hornback, K. Cudjoe

Conference on Applied Statistics in Agriculture

Justifications usually given for adopting an automated system pertain to a reduction in labor and an improvement in quality control. A manufacturer of a prototype instrument that automated some of the steps for culturing bacteria wanted to compare the automated system to the manual system. The manufacturer wanted to compare the two systems in 1) Total time needed to isolate the target bacteria, 2) Ability to isolate the target bacteria, 3) Amount of interference from background (non-target) bacterial growth, and 1) Extent of cross (sample to sample) contamination.

This paper presents the experimental design used to make these comparisons and …

Investigating Power Of Analysis Of Covariance Methods, James R. Schwenke, J. Mark Donovan

Conference on Applied Statistics in Agriculture

Analysis of covariance is a well-utilized statistical methodology. The procedure involves a series of statistical tests to first construct a most significant analysis model to characterize the effect of the covariate on response. Pairwise comparisons among treatments are then based on the finalized model.

For traditional Normal error assumptions, each step of the process is based on exact statistical tests. However, the series of statistical tests defines a conditional probability scheme with possible multiplicity issues. The question then becomes if the analysis of covariance methodology considered in entirety is able to maintain a nominal level of significance with good power. …

Starting Values For Proc Mixed With Repeated Measures Data, J. C. Recknor, W. W. Stroup

Conference on Applied Statistics in Agriculture

A major advantage of PROC MIXED for repeated measures data is that one could choose from many different correlated error models. However, MIXED uses default starting values that may cause difficulty obtaining REML estimates of the covariance parameters for several of the models available. This can take the form of excessively long run times or even failure to converge. We have written a program to obtain initial covariance parameter estimates that result in greatly improved performance of the REML algorithm. We will use two covariance models frequently of interest in animal health experiments, the first-order ante-dependence model [ANTE(l)] and the …

Analysis Of Genotype-By-Environment Interaction With Ammi Models Using Sas Proc Mixed, Raul E. Macchiavelli, James S. Beaver

Conference on Applied Statistics in Agriculture

Genotype-by-environment (GE) interaction can be analyzed using different approaches. Among these, the additive main effects and multiplicative interaction model yields useful interpretations and can be applied successfully to plant breeding programs. In this paper we review fitting strategies for this model and show how to combine the capabilities of the Mixed and IML procedures in SAS to fit this model. This permits straightforward use of likelihood-based inference in standard and non standard situations like complex experimental designs. The proposed procedures were applied to data from red mottled bean variety trials conducted in the Dominican Republic and Puerto Rico in 9 …

The Analysis Of Count Data In A One-Way Layout, Yuhua Wang, Dallas E. Johnson, Linda J . Young

Conference on Applied Statistics in Agriculture

An efficient score statistic for testing the equality of the means of several groups of count data in the presence of a common dispersion parameter is introduced and a new approximation to its distribution is given. The performance of the efficient score statistic using this approximation, the original efficient score statistic approximated by X ² (t -1), the likelihood ratio statistic and four more ANOVA methods based on raw data or transformed data are compared in terms of size and power by using Monte Carlo simulations. The efficient score statistic with its new approximation is recommended. An application is given.

Hydrological Normalization Of Nutrient Deliveries From Agricultural Catchments, Per Stalnacke, Anders Grimvall

Conference on Applied Statistics in Agriculture

Nutrient deliveries from agricultural catchments are strongly influenced by natural fluctuations in water discharge. Hydrological normalization of such data may therefore facilitate estimation of human impact on the environment. In the present study, we compared conventional statistical normalization techniques with a recently proposed, semi-parametric regression technique, which can accommodate time-dependent relationships between nutrient deliveries and water discharge. Case studies of agricultural catchments in Sweden and Norway demonstrated that all of the tested normalization techniques were able to remove a substantial fraction of the interannual variation in nitrogen deliveries, whereas normalization of phosphorus loads was problematic. Semi-parametric regression models were found …

A Computationally Efficient Method For Determining Significance In Interval Mapping Of Quantitative Trait Loci, Dan Nettleton

Conference on Applied Statistics in Agriculture

This paper provides a brief introduction to the mapping of quantitative trait loci (QTL). An example on mapping QTL for root thickness in rice is presented to illustrate popular statistical methods used in QTL mapping. Interval mapping is used in conjunction with permutation testing techniques to detect significant associations between genetic positions and quantitative traits while controlling overall type I error rate. A review of a recent technique that can greatly reduce the computational expense of permutation testing in QTL mapping is discussed. Theory is provided for an extension of recent results that may lead to more powerful methods of …

An Improved Estimator For Assessing The Measure Of Agreement With A Gold Standard, Brent D. Burch, Ian R. Harris, Roy T. St. Laurent

Conference on Applied Statistics in Agriculture

St. Laurent (1998, Biometrics 54, 537-545) developed a measure of agreement for method comparison studies in which an approximate method of measurement is compared to a gold standard method of measurement. The measure of agreement proposed was shown to be related to a population intraclass correlation coefficient. This paper develops a family of estimators for the measure of agreement based on pivotal quantities. A blend of two particular members of the family is suggested as an estimator itself. In general, this estimator outperforms the maximum likelihood estimator in terms of bias and mean-squared error.

Nonlinear Models For Multi-Factor Plant Nutrition Experiments, R. D. Landes, W. W. Stroup, E. T. Paparozzi, M. E. Conley

Conference on Applied Statistics in Agriculture

Plant scientists are interested in measuring plant response to quantitative treatment factors, e.g. amount of nutrient applied. Response surface methods are often used for experiments with multiple quantitative factors. However, in many plant nutrition studies, second-order response surface models result in unacceptable lack of fit. This paper explores multi-factor nonlinear models as an alternative. We have developed multi-factor extensions of Mitscherlich and Gompertz models, and fit them to data from experiments conducted at the University of Nebraska-Lincoln Horticulture department. These data are typical of experiments for which conventional response surface models perform poorly. We propose design selection strategies to facilitate …

Using Isotonic Regression To Improve Estimation In Factorial Experiments With Ordered Factor Levels, Matt Strand, Jim Higgins

Conference on Applied Statistics in Agriculture

In many designed experiments in agriculture and the life sciences, a researcher can anticipate the direction that responses will take when treatments are varied. For example, in a 2-way factorial, a researcher may know that increasing the levels of nitrogen and phosphorus will increase yields of a crop. Classical analysis of variance does not take into account a known ordering among population means. However, it can be shown that by restricting the estimates of means to have the same ordering as the anticipated ordering of population means, a reduction in mean-squared errors of estimators will likely occur, often by more …

Characterizing The Statistical Distribution Of Organic Carbon And Extractable Phosphorus At A Regional Scale, John J. Brejda, David W. Meek, Douglas L. Karlen

Conference on Applied Statistics in Agriculture

Greater awareness of potential environmental problems has created the need to monitor total organic carbon (TOC) and extractable phosphorus (P) concentrations at a regional scale. The probability distribution of these soil properties can have a significant effect on the power of statistical tests and the quality of inferences applied to these properties. The objectives of this study were to: (1) evaluate the probability distribution of TOC and extractable P at the regional scale in three Major Land Resource Areas (MLRA), and (2) identify appropriate transformations that will result in a normal distribution. Both TOC and extractable P were non-normally distributed …

Analysis Of Nuclei Fluorescence Histograms Using Non-Linear Functions Or Wavelets, Susanne Aref, Maria Kocherginsky, Carrie A. Northcott, Lane A. Rayburn

Conference on Applied Statistics in Agriculture

Histograms based on 5,000 nuclei from cells (Chinese hamster ovary cells, bone marrow cells) are used to determine the coefficient of variation (CV) of observations surrounding the highest peak. The cells are subjected to various treatments, for example exposure to herbicides. By eyeballing the histogram, an interval under the highest peak is determined. The CV calculated from the histogram on the eyeballed interval is the response variable in an ANOVA. To avoid the subjectivity of eyeballing the histogram, non-linear functions such as the Gaussian density function can be used to model the histogram. The CV may then be determined from …

On Using Proc Mixed For Longitudinal Data, Walter W. Stroup

Conference on Applied Statistics in Agriculture

PROC MIXED has become a standard tool for analyzing repeated measures data. Its popularity results from a wide choice of correlated error models compared to other software, e.g. PROC GLM. However, PROC MIXED's versatility comes at a price. Users must take care. Problems may result from MIXED defaults. These include: questionable criteria for selecting correlated error models; starting values that may impede REML estimation of covariance components; and biased standard errors and test statistics. Problems may be induced by inadequate design. This paper is a survey of current knowledge about mixed model methods for repeated measures. Examples are presented using …

Modeling The Fate Of Toxic Chemicals In Soils, Anabayan Kessavalou, Anne M. Parkhurst

Conference on Applied Statistics in Agriculture

Studies on the fate of toxic chemicals in soils are often reported with a minimum of descriptive statistics. Use of modeling techniques to describe the kinetics of chemical degradation provides a better understanding of the fate of chemicals in soil systems. When modeling nonlinear systems, assumptions made about the error term greatly influence the parameter estimation. Inappropriate use of linearization and failure to account for autocorrelated errors may result in inaccurate models. Information is also needed about the effects of the magnitude of autocorrelation on parameter estimation. The exponential decay function was chosen to fit the data obtained from a …

Estimating The Likelihood Of Yellow Starthistle Occurrence Using An Empirically Derived Nonlinear Regression Model, Bahman Shafii, William J. Price, Lawrence W. Lass, Donn C. Thill

Conference on Applied Statistics in Agriculture

Yellow starthistle is a noxious weed common in the semiarid climate of Central Idaho and other western states. Early detection of yellow starthistle and predicting its infestation potential have important scientific and managerial implications. Weed detection and delineation are often carried out by visual observation or survey techniques. However, such methods may be ineffective in detecting sparse infestations. The distribution of yellow starthistle over a large region may be affected by various exogenous variables such as elevation, slope and aspect. These landscape variables can be used to develop prediction models to estimate the potential invasion of yellow starthistle into new …

Statistics In The New Millennium: Some Personal Views, Bryan F.J. Manly

Conference on Applied Statistics in Agriculture

In this paper I discuss three topics that I believe are relevant to the subject of statistics in the new millennium: (a) the impact of computers, and the state of computer-intensive methods as far as practical applications of statistics are concerned; (b) methods for the analysis of the extremely large data sets that are now becoming available; and (c) the use of statistics by scientists in general. For the first topic I suggest that the main advantage of computer-intensive methods is that they can under certain circumstances give simple and believable answers to questions when other methods fail. However, I …

Editor's Preface And Table Of Contents, George A. Milliken

Conference on Applied Statistics in Agriculture

These proceedings contain papers presented in the eleventh annual Kansas State University Conference on Applied Statistics in Agriculture, held in Manhattan, Kansas, April 25-27, 1999.

How Proteins Fold, Flex, And Bind Other Molecules, Leslie A. Kuhn, Volker Schnecke, Michael L. Raymer, Paul C. Sanschagrin

Kno.e.sis Publications

No abstract provided.

111th Session Iowa Academy Of Science Awards Luncheon, April 23, 1999, Iowa Academy Of Science

Iowa Academy of Science Documents

Program:

--- Introductions - James Christiansen, President
--- Recognition of students participating in various statewide activities - Ed Rezabek, Chair, Student Programs Committee
--- Presentation of scholarship winners and 2000 AJAS representiatives - Brenda Jordan, Interim Director, Iowa Junior Academy of Science
--- Presentation of Excellence in Science Teaching Awards - Peg Steffen, Director, ESTA Program

Program Abstracts, 111th Session, Iowa Academy Of Science, April 23-24, 1999, Iowa Academy Of Science

Iowa Academy of Science Documents

Presentation abstracts from the annual meeting of the Iowa Academy of Science

Iowa Academy Of Science President's Banquet [111th Session], Iowa Academy Of Science

Iowa Academy of Science Documents

Program:

Introductions
Awards:
Distinguished Iowa Science Teaching: Somnath Sarkar
Distinguished Iowa Scientist: Steve Feller
Distinguished Service: Daryl Smith
President's Address - James Christiansen
Response - Neil Bernstein, President-Elect
General Sessions II - Dr. Charles M. Tipton, "The Iowa Wrestling Studies: From Athens to Iowa City"

Shout With The Largest Mob : Toward A Model For Primitive Communication In Mobile Automata, Rebecca A. Weber

Honors Theses

We consider the problem of simulating communication between independent, autonomous agents, or machines, using only local rules with no global control over the agents' behavior. First, we construct an algorithm by which the machines will avoid collisions with each other and with boundaries or obstacles. Noting that collision avoidance alone will not result in higher-level behavior, and with the goal of creating agents which would self-organize, we begin to develop a signalling system by which agents can communicate. This leads to a new method for modeling agent motion in the plane. Throughout, we are motivated by possible linkages between our …

Collaborative Decision-Support And The Human-Machine Relationship, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Human beings are inquisitive creatures who seek explanations for all that they observe and experience in their living environment. While this quest for understanding is central to our success in adapting to a changing environment, it is also a major cause of our willingness to accept partial understandings and superficial explanations when the degree of complexity of the problem situation confounds our current cognitive capabilities. In other words, a superficial or partial explanation is considered better than no explanation at all. As flawed as this approach may be, it has helped us to solve difficult problems in stages. By first …

Proceedings Of The 1999 Onr Decision-Support Workshop Series: A Decision-Making Tools Workshop, Collaborative Agent Design Research Center

Collaborative Agent Design (CAD) Research Center

The rationale of the Workshop rests on some very simple observations. It is well known that every situation encountered by individuals and organizations demands an appropriate response. The choice of such a response from among a multitude of options is the decision-making process. Simple situations that give rise to a small number of options allow the decision maker to decide on a course of action without great effort. This state of affairs changes dramatically when the situations are complex and involve a large number of factors. In this case, an extensive field of options is engendered that makes it impossible …