Digital Commons Network^™

Vegetation And Climate Change On The Bolivian Altiplano Between 108,000 And 18,000 Years Ago, Alex Chepstow-Lusty, Mark B. Bush, Michael R. Frogley, Paul A. Baker, Sherilyn C. Fritz, James Aronson

Department of Earth and Atmospheric Sciences: Faculty Publications

A 90,000-yr record of environmental change before 18,000 cal yr B.P. has been constructed using pollen analyses from a sediment core obtained from Salar de Uyuni (3653 m above sea level) on the Bolivian Altiplano. The sequence consists of alternating mud and salt, which reflect shifts between wet and dry periods. Low abundances of aquatic species between 108,000 and 50,000 yr ago (such as Myriophyllum and Isoëtes) and marked fluctuations in Pediastrum suggest generally dry conditions dominated by saltpans. Between 50,000 yr ago and 36,000 cal yr B.P., lacustrine sediments become increasingly dominant. The transition to the formation of …

Vertical Movement Of Water In A High Plains Aquifer Induced By A Pumping Well, Xunhong Chen, Yanfeng Yin, James W. Goeke, Robert F. Diffendal Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

Field observation and numerical simulations were carried out to evaluate the hydraulic relationship between the shallow and deep aquifer of a High Plains Aquifer system, in which shallow and deep aquifers are separated by an aquitard. Pumping from the lower aquifer resulted in a small drawdown in the upper aquifer and a larger drawdown in the aquitard; pumping from the shallow aquifer caused a small drawdown in the aquitard and the deep aquifer. Analysis of pumping test data gives the values of the hydraulic conductivity of the aquitard and the deep aquifer. Long-term observation of groundwater levels in the shallow …

Discovering Work Relationships And Their Effect On Job Satisfaction : An Exploratory Study Of A Small Organization In The Upper Midwest, Heather Brooke Berglove

Theses and Dissertations

No abstract provided.

Finite Element Analysis Of Bjork-Shiley Convexo-Concave Heart Valve, Sumit Agrawal

Theses and Dissertations

No abstract provided.

Doing Water Quality Credit Trading Right, Alexandra Dapolito Dunn

Elisabeth Haub School of Law Faculty Publications

No abstract provided.

Do Maps Guide The Way To Npd Success? Theoretical And Practical Aspects Of Knowledge Mapping In Product Development, Antonie J, Jetter

Engineering and Technology Management Faculty Publications and Presentations

New product development success largely depends on the ability to combine newly acquired information on customer demands and technological options with knowledge that exists within the company. Project organization and high employee turnover, however, make it difficult to be informed about what knowledge is available within the company and to access it successfully. Knowledge maps, a popular concept in present knowledge management, offer a possible solution by ?guiding the way to knowledge?. Their purpose, structure and content varies greatly, as does their ability to capture different aspects of knowledge. This paper investigates the theoretical basis of different types of knowledge …

Social Indicators In Cleveland's Ward 17, Mark Salling, Sharon Bliss, Joseph Ahern

All Maxine Goodman Levin School of Urban Affairs Publications

No abstract provided.

Fast Algorithms For Layered Media, Weng Cho Chew, Bin Hu, Y. C. Pan, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper gives an overview of computational electromagnetics for simulating complex structures with a large number of unknowns using integral equation method. First, it discusses the pros and cons of differential equation solvers versus integral equation solvers. Then it gives an overview of different fast algorithms for solving integral equations. It also discusses the difficulty of solving electromagnetic problems in the "twilight zone" between static and full-wave electromagnetics. Finally, it discusses various methods for fast solutions of scattering and coupling problems involving layered media both for statics and dynamic problems, and presents some numerical results. © 2005 Académie des sciences. …

Rcu Semantics: A First Attempt, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

There is not yet a formal statement of RCU (read-copy update) semantics. While this lack has thus far not been an impediment to adoption and use of RCU, it is quite possible that formal semantics would point the way towards tools that automatically validate uses of RCU or that permit RCU algorithms to be automatically generated by a parallel compiler. This paper is a first attempt to supply a formal definition of RCU. Or at least a semi-formal definition: although RCU does not yet wear a tux (though it does run in Linux), at least it might yet wear some …

Incompressible Finite Elements Via Hybridization. Part Ii: The Stokes System In Three Space Dimensions, Bernardo Cockburn, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

We introduce a method that gives exactly incompressible velocity approximations to Stokes ow in three space dimensions. The method is designed by extending the ideas in Part I (http://archives.pdx.edu/ds/psu/10914) of this series, where the Stokes system in two space dimensions was considered. Thus we hybridize a vorticity-velocity formulation to obtain a new mixed method coupling approximations of tangential velocity and pressure on mesh faces. Once this relatively small tangential velocity-pressure system is solved, it is possible to recover a globally divergence-free numerical approximation of the fluid velocity, an approximation of the vorticity whose tangential component is continuous across …

Incompressible Finite Elements Via Hybridization. Part I: The Stokes System In Two Space Dimensions, Bernardo Cockburn, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

In this paper, we introduce a new and efficient way to compute exactly divergence-free velocity approximations for the Stokes equations in two space dimensions. We begin by considering a mixed method that provides an exactly divergence-free approximation of the velocity and a continuous approximation of the vorticity. We then rewrite this method solely in terms of the tangential fluid velocity and the pressure on mesh edges by means of a new hybridization technique. This novel formulation bypasses the difficult task of constructing an exactly divergence-free basis for velocity approximations. Moreover, the discrete system resulting from our method has fewer degrees …

Monitoring Spatial And Temporal Water Quality Changes In Iowa Lakes Using Airborne Hyperspectral Imagery, Nathan Robert Green

Dissertations and Theses @ UNI

The U.S. Environmental Protection Agency (US EPA) has identified more than 20,000 water bodies across America as polluted mainly due to agricultural non-point source pollution. Current techniques for monitoring and assessing the quality of waters in streams, reservoirs, lakes, and estuaries involve on site measurements and/or the collection of water samples for subsequent laboratory analyses. While this approach yields accurate measurements for a point in time and space, it is expensive, laborious, and cannot provide a temporal or spatial overview of water-quality trends. To overcome this liability, state and local agencies are seeking alternative and more cost effective methods. A …

Sticks, Stones, & Stigmas: A Social-Cognitive Account Of Stereotype Threat Mechanisms, Michael C. Philipp

Dissertations and Theses @ UNI

Stereotype threat effects have been a popular domain of much psychological inquiry over the past decade. A number of psychological dispositions (e.g., high levels of stigma consciousness, high levels of social dominance orientation, and high levels of domain identification), situational factors (e.g., out-group presence and task difficulty), and physiological characteristics ( e.g., levels of circulating testosterone) have been identified as factors that determine one's susceptibility to the performance debilitating effects of negative stereotype activation. Although each of these variables has been found to be important in eliciting underperformance under threat, no attempts have yet investigated the relationships between these variables. …

Using Office Referral Data To Help Understand School-Wide Discipline, Sarah Remakel-Henkels

Dissertations and Theses @ UNI

Some schools looking to create and maintain a safe and supportive learning environment implement Positive Behavior Supports (PBS). Maintaining a safe and supportive school requires a solid sense of the current school climate and a continuous improvement process for measuring progress and making appropriate corrections. Schools need to be keeping track of whether a safe, supportive learning community is being provided to all students all of the time through key indicator data.

Due to the increased amount of accountability being placed upon schools and states through NCLB, there is also an increased amount of academic data collection required. One school …

Achievement Goal Theory: A Preliminary Study Examining Educators' Motivational Beliefs And Practices, Marc Groen

Dissertations and Theses @ UNI

Achievement goal theory has become one of the most promising motivational theories examining both student motivation and achievement. The purpose of this study was to expand the current body of research on achievement goal theory by exploring educators' motivational beliefs and instructional practices. Data was collected from two Eastern Iowa school districts using an online survey. Results from this preliminary study provide important information about the practical nature of motivational problems from the perspective of elementary and middle school educators. The author explores the implications of the findings for educators, school psychologists, and future research.

Amyotrophic Lateral Sclerosis Case-Control Study: Past Chemical Exposures And The Measurement Of The Red Blood Cell Acetylcholinesterase Reactivity In Vitro When Challenged At Various Dosages By Chlorpyrifos-Oxon, Naomi J. Bienfang

Dissertations and Theses @ UNI

The purpose of this study was to analyze the red blood cell acetylcholinesterase (RBC AChE) reactivity levels among persons with amyothropic lateral sclerosis (PALS) (cases) and their controls when challenged with the oxon form of the organophosphate insecticide chlorpyrifos. The ultimate objective was to determine if a correlation exists between the RBC AChE reactivity level and the participants' disease status and/or exposure to toxins through occupations and hobbies.

Cases in this study were individuals diagnosed by a neurologist with sporadic ALS. Controls were individuals who were not genetically related to the PALS and were neuromuscular disease free. Controls were a …

Agricultural Pollution Of Ground Water Near Gilbertville, Iowa, Paula Frost Even

Dissertations and Theses @ UNI

The transport of nutrients and contaminants from farm fields to the aquifer surrounding Gilbertville, Iowa, was monitored over a six-month period. The Gilbertville city water supply is obtained from the Silurian-Devonian aquifer, which has been determined to be highly susceptible to contamination because of the hydraulic characteristics of the aquifer and the overlying materials that allow contaminants to move to the aquifer fairly quickly. Monthly water samples were collected from April through September of 2004 from 26 private wells and 8 surface water sites within the source water protection area of the town's three wells. Each sample was tested for …

Extraction Of Transportation Infrastructure From Hyperspectral Remote Sensing Data, James Paul Gerjevic

Dissertations and Theses @ UNI

The goal of this study was to extract transportation infrastructure features from hyper-spectral imagery using data from the high resolution Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). A "Minimum Noise Fraction" (MNF) and a classification and regression tree (CART) were used to reduce the number of spectral dimensions to be analyzed. Then, hyperspectral classifiers such as the Spectral Angle Mapper (SAM), Mixture-tuned matched filtering (MTMF) and mixture-tuned matched filtering combined with classification and regression tree (MTMF-CART) were used to extract the transportation infrastructures from the image using different image processing software such as ENVI and ERDAS IMAGINE. Finally, WinTopo software was used …

Synthesis And Characterization Of Rhodium And Iridium Complexes With The Bis(Dimethylsilylcyclopentadienyl) Ligand, Gordon J. Hunter

Dissertations and Theses @ UNI

The synthesis of transition-metal complexes ( n5 -C5H3SiMe2)2[Rh(CO)2]2 and ( n5- -C5H3SiMe2)2[Rh(CO)2]2, both featuring the bis( dimethylsilylcyclopentadienyl) ligand, is reported. Preparation of the rhodium complex yielded a cis:trans ratio of 1 :2, while the iridium analogue generated a 2: 1 ratio. Thermal reaction of cis-( n5- - C5H3SiMe2)2[Rh(CO)2]2 yields cis-( n5 -C5H3SiMe2)2Rh2(CO)3, which features an asymmetrically bridging carbonyl ligand. Reaction of I2with cis-( n5- - C5H3SiMe2)2[Ir(CO)2]2 yields cis-( n5 -C5H3SiMe2)2[Ir(CO)I2]2 Synthesis of ( n5- - C5H3SiMe2)2[Ir(cyclooctadiene)h in a cis:trans ratio of 1 :2.5 is also reported.

A Web-Based Intelligent Spatial Decision Support System For Planning Snow Removal Operations, Shriram Ilavajhala

Dissertations and Theses @ UNI

Providing speedy and cost-effective snow removal management during winter months proves to be an overwhelming task for the local and government personnel. Considering the importance and the massive costs involved in snow removal operations, it is essential that the snowplowing operations be carefully and efficiently planned, so as to minimize the costs and provide a quick response. However, the existing methods for snowplowing planning operations are mostly handled manually. For example, the resource allocation and management is done manually without using any analytical tool for optimization, and the routing is done often times without considering the least costly route to …

The Efficacy Of Writing Course Placement At An Iowa Community College, Kristine D. Owens

Dissertations and Theses @ UNI

The purpose of this study was to investigate the efficacy of writing course placement at an Iowa community college. The following questions were addressed: What indicators, separately or in combination, resulted in an appropriate or inappropriate student writing placement? (a) To what extent did the COMPASS test result in an appropriate placement? (b) To what extent did the self-directed essay result in an appropriate placement? (c) To what extent did a student's preference result in an appropriate placement?

This study was important to understand how the “directed self-placement” model, adapted from Royer and Gilles (1998, p. 1), impacted the institution's …

Inventory Simulation And Optimization Using System Dynamics, Structural Modeling Equations And Genetic Algorithms In The Drivetrain Division Of An Automotive Manufacturer, Marco Sisfontes-Monge

Dissertations and Theses @ UNI

Strategic planning and control are among the most critical activities that modern enterprises require to succeed in the global economy. This research is an original study that investigated the combination of tools and methodologies in order to apply them to a midwestern tractor manufacturer. The current study identified the constraints applicable to a polishing line in the Drivetrain Division of a major tractor manufacturer interested in exploring alternative techniques to improve its worldwide manufacturing operations.

The specific questions that this project tried to respond are stated as follows:

1. What were the most important variables that affected inventory levels of an …