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2011

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Field-Based Constraints On The Origin Of The Benton Uplift, Ouachita Mountains, Rachel Victoria Keng Dec 2011

Field-Based Constraints On The Origin Of The Benton Uplift, Ouachita Mountains, Rachel Victoria Keng

Graduate Theses and Dissertations

The Ouachita Mountains are an east-west trending fold-and-thrust belt exposed in west central Arkansas and southeastern Oklahoma. The Mississippian-Pennsylvanian Ouachita orogeny occurred when the Sabine arc terrane collided during south-facing subduction, during closure of the Cambrian passive margin of the North American plate. Deep-water Paleozoic strata were incorporated into an accretionary wedge as the Sabine terrane approached the North American plate. Folds and thrust faults in the Ouachita Mountains generally verge north due to tectonic transport of an accretionary wedge from south to north. Structures in the Benton and Broken Bow Uplifts (located in the core of the wedge) locally …


Hear My Voice: An Examination Of The Views Of Parents Who Are Raising Children Of African American Descent, Chavez Maurice Phelps Dec 2011

Hear My Voice: An Examination Of The Views Of Parents Who Are Raising Children Of African American Descent, Chavez Maurice Phelps

All-Inclusive List of Electronic Theses and Dissertations

Researchers have demonstrated that children who attend early childhood education programs benefit academically and socially (National Institute for Early Education Research, 2003). However, other researchers have shown that African American students may still lag behind their counterparts when they enter school (National Center for Education Statistics ([NCES], 2004). To explain this phenomenon, scholars and practitioners have relied on deficit theories, such as Ruby Payne’s (2005) culture of poverty theory or John Ogbu’s (1992) oppositional culture identity theory, which shift the blame solely on the child or their parents. However, there are other researchers who have stressed the importance of examining …


Localization Of Objects Using Cross-Correlation Of Shadow Fading Noise And Copulas, Mohammed Rana Basheer, Sarangapani Jagannathan Dec 2011

Localization Of Objects Using Cross-Correlation Of Shadow Fading Noise And Copulas, Mohammed Rana Basheer, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

While fading, in general, is detrimental to accurately localizing a target, fading correlation between adjacent receivers may be exploited to improve localization accuracy. Therefore, this paper presents a novel wireless localization scheme that employs a combination of cross-correlation between shadow fading noise and copula technique to recursively estimate the location of a transmitter. a stochastic filter that models multipath fading as an Ornstein-Uhlenbeck process followed by a Generalized Auto Regressive Conditional Heteroskedasticity (GARCH) filtering is proposed to extract shadow fading residuals from measured RSSI values. Subsequently, Student-t Copula function is used to create the log likelihood function, which acts as …


Contingency Constrained Economic Dispatch In Smart Grids With Correlated Demands, Yiyu Shi, Jinjun Xiong Dec 2011

Contingency Constrained Economic Dispatch In Smart Grids With Correlated Demands, Yiyu Shi, Jinjun Xiong

Electrical and Computer Engineering Faculty Research & Creative Works

Contingency constrained economic dispatch has been an extensively studied research topic. However, most existing works assume that the load demands at all buses are given. Such an assumption works well for conventional power grids, where the load demands are relatively easy to predict. We can select a few representative demand profiles and perform economic dispatch over them. However, such a practice will no longer work in smart grids, where the load demands fluctuate dramatically. We will need a huge number of demand profiles to cover all possible scenarios, which is computationally expensive. to address the problem, we propose a parameterized …


Eigenvalue Distributions Of Mimo Rayleigh-Product Channels With Arbitrary-Power Co-Channel Interference And Noise, Yongpeng Wu, Shi Jin, Xiqi Gao, Chengshan Xiao, Matthew R. Mckay Dec 2011

Eigenvalue Distributions Of Mimo Rayleigh-Product Channels With Arbitrary-Power Co-Channel Interference And Noise, Yongpeng Wu, Shi Jin, Xiqi Gao, Chengshan Xiao, Matthew R. Mckay

Electrical and Computer Engineering Faculty Research & Creative Works

This paper studies the eigenvalue distributions of multiple-input multiple-output (MIMO) Rayleigh-product channels in the presence of both co-channel interference and thermal noise. We first present exact expressions for the marginal ordered eigenvalue distributions of the channel Gram matrix when multichannel beamforming is employed, from which we obtain exact results of the outage probability on each eigenmode. Our results apply to a wide class of multichannel systems which transmit on the eigenmodes of the MIMO channel, allowing for transmission on any numbers of eigen subchannels, with any numbers of antennas, any numbers of scatterers in the environment, and any numbers of …


On The Preconditioner Of Conjugate Gradient Method A Power Grid Simulation Perspective, Chung Han Chou, Nien Yu Tsai, Hao Yu, Che Rung Lee, Yiyu Shi, Shih Chieh Chang Dec 2011

On The Preconditioner Of Conjugate Gradient Method A Power Grid Simulation Perspective, Chung Han Chou, Nien Yu Tsai, Hao Yu, Che Rung Lee, Yiyu Shi, Shih Chieh Chang

Electrical and Computer Engineering Faculty Research & Creative Works

Preconditioned Conjugate Gradient (PCG) method has been demonstrated to be effective in solving large-scale linear systems for sparse and symmetric positive definite matrices. One critical problem in PCG is to design a good preconditioner, which can significantly reduce the runtime while keeping memory usage efficient. Universal preconditioners are simple and easy to construct, but their effectiveness is highly problem dependent. on the other hand, domain-specific preconditioners that explore the underlying physical meaning of the matrices usually work better but are difficult to design. in this paper, we study the problem in the context of power grid simulation, and develop a …


Method Development And Validation Of The Quantitation Of 19 Antipsychotics Using Deuterated Internal Standards, Anthony S. Epps Dec 2011

Method Development And Validation Of The Quantitation Of 19 Antipsychotics Using Deuterated Internal Standards, Anthony S. Epps

Chemistry Theses

Antipsychotic drugs or neuroleptics are used primarily for psychiatric disorders such as schizophrenia, psychosis, and bipolar disorder. In forensic science antipsychotics are drugs of considerable interest because of their potential abuse, involvement in suicides, and they are frequently associated with sudden death investigations. Well-characterized and fully validated analytical data is necessary to generate reproducible and reliable results. As a result, data can be correctly interpreted and objectively demonstrate in its applicability for the intended use. This research has developed and validated a method that is selective, sensitive and accurate using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the simultaneous determination of …


Econometric Analysis Of Erie County, Ny Schools: The Effects Of Poverty On Our Schools And Evaluating Possible Solutions, Ryan B. Keem Dec 2011

Econometric Analysis Of Erie County, Ny Schools: The Effects Of Poverty On Our Schools And Evaluating Possible Solutions, Ryan B. Keem

Multidisciplinary Studies Theses

School districts in the Buffalo Metropolitan Area are very segregated by socioeconomic status which has resulted in very different educational outcomes for the region's students as measured by New York State assessment results at the 4th grade and 8th grade level in English Language Arts and Math. This study measured the correlation between average test score results for each school building in Erie County and the rate of low-income students in those schools. The multiple regression analysis performed controlled for race, percentage of students that had a disability, class size, and per-pupil expenditures by the district.

The study …


Keeping It Real: Teaching And Learning In The Harry Potter Series, Mary E. N. Vaughn Dec 2011

Keeping It Real: Teaching And Learning In The Harry Potter Series, Mary E. N. Vaughn

Honors Theses

Scholars have noted that embedded in the plot of J. K. Rowling’s Harry Potter series are representations of teaching and learning in and outside of the classroom. In fact, much study has been dedicated to analyzing pedagogical techniques present in the series, some of which studies I will be discussing below. The novels also reflect real problems and issues in the classroom. How people react to the educational process depicted in the text grows out of popularized conceptions or misconceptions of real-world education. Considering that Rowling was an educator before becoming established as a writer, she probably has some ideas …


Directional Limits On Persistent Gravitational Waves Using Ligo S5 Science Data, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2011

Directional Limits On Persistent Gravitational Waves Using Ligo S5 Science Data, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2 - 20 x 10-50 strain2 Hz-1 and 5 - 35 x 10-49 strain2Hz-1sr-1 for pointlike and extended sources, respectively. The latter result is the …


Visualizing The Spatial Localization Of Active Matrix Metalloproteinases (Mmps) Using Maldi Imaging Ms, Sasirekha Muruganantham Dec 2011

Visualizing The Spatial Localization Of Active Matrix Metalloproteinases (Mmps) Using Maldi Imaging Ms, Sasirekha Muruganantham

Graduate Theses and Dissertations

Biomaterial implantation induces the foreign body response (FBR). Development of longer-term implants relies on the thorough understanding of the FBR. The progression of the FBR is regulated by a number of biomolecules including cytokines, chemokines, and matrix metalloproteinases (MMPs). The nature of the FBR requires the spatial and temporal regulation of these mediators. MMPs are an extremely large and diverse group of enzymes that play key roles in regulating the FBR. Precise spatiotemporal regulation of MMPs defines their proteolytic activities. The aim of this project is to develop a new bioanalytical method to visualize the localization of active MMPs at …


Teachers' Perceptions Toward The Secondary Physical Education Program In The State Of Kuwait, Khaled A. Al-Kandari Dec 2011

Teachers' Perceptions Toward The Secondary Physical Education Program In The State Of Kuwait, Khaled A. Al-Kandari

Graduate Theses and Dissertations

The purpose of this research was to determine the perceptions of physical education teachers and supervisors toward the secondary physical education program in eight domains in the State of Kuwait. Stratified and cluster sampling were used to select two schools of female teachers and two schools of male teachers from each district (6 districts); therefore, 24 schools were selected randomly. One hundred thirty-eight physical education teachers were selected and 66 supervisors were selected. A four-point rating scale (i.e., strongly disagree to strongly agree) and open-ended questions were included in the survey. Cronbach's alpha reliability, descriptive statistics, and independent sample t …


Application Of The Empirical Mode Decomposition On The Characterization And Forecasting Of The Arrival Data Of An Enterprise Cluster, Linh Bao Ngo Dec 2011

Application Of The Empirical Mode Decomposition On The Characterization And Forecasting Of The Arrival Data Of An Enterprise Cluster, Linh Bao Ngo

Graduate Theses and Dissertations

Characterization and forecasting are two important processes in capacity planning. While they are closely related, their approaches have been different. In this research, a decomposition method called Empirical Mode Decomposition (EMD) has been applied as a preprocessing tool in order to bridge the input of both characterization and forecasting processes of the job arrivals of an enterprise cluster. Based on the facts that an enterprise cluster follows a standard preset working schedule and that EMD has the capability to extract hidden patterns within a data stream, we have developed a set of procedures that can preprocess the data for characterization …


The Design, Synthesis And Application Of A Novel Class Of N-Heterocyclic Carbene Catalysts, Abigail Lynn Hubbard Dec 2011

The Design, Synthesis And Application Of A Novel Class Of N-Heterocyclic Carbene Catalysts, Abigail Lynn Hubbard

Graduate Theses and Dissertations

A copper carbenoid representative of a novel class of N-heterocyclic carbene (NHC) catalysts has been synthesized. This compound was characterized by X-ray crystallography and was found to confirm the rationale of our synthetic design: The C2-symmetric structure places four stereocenters in close proximity (<5Å) to the reactive site of the carbene via a trans-annular gearing effect. The copper carbenoid was found to catalyze the hydrosilylation of prochiral ketones with superb selectivity in high yield.


Improvements On Just-About-Right (Jar) Scales As Product Optimization Tools Using Kano Modeling Concepts, Bangde Li Dec 2011

Improvements On Just-About-Right (Jar) Scales As Product Optimization Tools Using Kano Modeling Concepts, Bangde Li

Graduate Theses and Dissertations

Attribute Kano characteristics are useful in product design to prioritize development efforts. However, attribute Kano characteristics have not been discussed and applied to product optimization when using Just-About-Right (JAR) scales. Product optimizations without identifying attributes Kano characteristics can be misleading. The two objectives in this research were: 1. Determine attribute Kano categories using a modified classic Kano classification methodology. 2. Propose a method to measure attribute performance and identify attribute Kano characteristics to direct product optimization. Two methodologies of attribute Kano classification were investigated. In experiment one, a modified classic Kano methodology was employed to determine attribute Kano categories through …


High Performance Geospatial Analysis On Emerging Parallel Architectures, Seth Warn Dec 2011

High Performance Geospatial Analysis On Emerging Parallel Architectures, Seth Warn

Graduate Theses and Dissertations

Geographic information systems (GIS) are performing increasingly sophisticated analyses on growing data sets. These analyses demand high performance. At the same time, modern computing platforms increasingly derive their performance from several forms of parallelism. This dissertation explores the available parallelism in several GIS-applied algorithms: viewshed calculation, image feature transform, and feature analysis. It presents implementations of these algorithms that exploit parallel processing to reduce execution time, and analyzes the effectiveness of the implementations in their use of parallel processing.


Analyzing Spring Freeze Impacts On Deciduous Forest Productivity Using Modis Satellite Imagery, Karl Lintvedt Dec 2011

Analyzing Spring Freeze Impacts On Deciduous Forest Productivity Using Modis Satellite Imagery, Karl Lintvedt

Graduate Theses and Dissertations

The impacts of an April 2007 spring freeze event on the productivity of deciduous broadleaf forest were analyzed using geographic information system (GIS) tools. Forest productivity was modeled using the Enhanced Vegetation Index (EVI), as recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor. Measures of spatial autocorrelation were used to quantify the degree of spatial congruence between a map depicting the severity of the freeze event, and maps modeling forest productivity throughout the year. The results show a geographic correlation between the unseasonably low minimum temperatures sustained during the freeze and the unusually low forest productivity that followed. …


Factors Influencing Teaching Efficacy Among Kansas Career And Technical Education Faculty, Douglas Lee Younger Dec 2011

Factors Influencing Teaching Efficacy Among Kansas Career And Technical Education Faculty, Douglas Lee Younger

Graduate Theses and Dissertations

The purpose of this study was to examine the levels of teaching efficacy among postsecondary career and technical education faculty at Kansas technical and community colleges. Postsecondary career and technical education faculty at Kansas technical and community colleges were asked to complete an instrument designed to measure their levels of teaching efficacy based upon a modified version of the Teachers' Sense of Efficacy Scale, originally developed by Woolfolk and Hoy (1998). The entire population of postsecondary career and technical education faculty from Kansas technical and community colleges (N=726) were surveyed and a total of n=181 (24.9%) completed the instrument. Data …


Exploring First Generation African American Graduate Students: Motivating Factors For Pursuing A Doctoral Degree, Stephanie G. Adams Dec 2011

Exploring First Generation African American Graduate Students: Motivating Factors For Pursuing A Doctoral Degree, Stephanie G. Adams

Graduate Theses and Dissertations

The purpose for conducting the study was to examine the factors that motivate African-American first-generation students to pursue doctoral education at a four-year public university. There has been little research on the influence academic or non-academic factors have on first-generation graduate student motivation. Similarly, little research exists that explored how factors might vary by ethnicity. Based on the projected increase of post-baccalaureate enrollment each year (Aud, Hussar, Planty, Snyder, Bianco, Fox, Frohlich, Kemp, Drake, 2010), first-generation African-Americans will become more interested in attending graduate school. It is important to gain a better understanding of the factors and influences that impact …


Dynamics And Catalytic Resolution Of Selected Chiral Organolithiums, Timothy Kum Beng Dec 2011

Dynamics And Catalytic Resolution Of Selected Chiral Organolithiums, Timothy Kum Beng

Graduate Theses and Dissertations

One of the most important developments of the last decade has been the emergence of new methods to dynamically resolve racemic organolithiums using stoichiometric amounts of the chiral ligand. When this concept is implemented successfully, it obviates the need for covalently attached chiral auxiliary based methods, asymmetric deprotonation, and asymmetric synthesis of a precursor stannane as ways to access enantioenriched organolithium compounds for use in asymmetric synthesis. Since certain electrophiles consume the chiral ligand, it is desirable to render this process catalytic in the chiral ligand.

As part of a larger study on the amenability of chiral organolithiums to a …


Subcritical Water Hydrolysis Of Whey Proteins, Ashley Dawn Espinoza Dec 2011

Subcritical Water Hydrolysis Of Whey Proteins, Ashley Dawn Espinoza

Graduate Theses and Dissertations

Hydrolyzing food by-products is a unique approach to potentially increase by-product value and reduce waste. An abundant by-product of cheese production, whey, contains all essential amino acids and some distinctive peptides with functional and nutraceutical properties. Typically, proteins from whey are tailored for specific uses by chemical or enzymatic hydrolysis; however, subcritical water hydrolysis is a novel alternative used successfully to hydrolyze various substrates. Nevertheless, minimal research exists on: (1) the hydrolysis of whey protein; (2) the incorporation of additives; (3) the hydrolysis of whole whey; and (4) the production of volatiles when using subcritical water hydrolysis.

Therefore, whey protein …


Sublime Beauty & Horrible Fucking Things - The Finer Worlds Of Warren Ellis, William James Allred Dec 2011

Sublime Beauty & Horrible Fucking Things - The Finer Worlds Of Warren Ellis, William James Allred

Graduate Theses and Dissertations

This work constitutes an in-depth discussion of the muted postmodern characteristics of contemporary comics writer and novelist Warren Ellis, highlighting his major long-form works within comics, Planetary, Transmetropolitan, StormWatch, and The Authority, as well as several shorter works such as Ocean, Orbiter, and Global Frequency. In addition, Ellis is situated within the British science fiction tradition, specifically, the British Boom movement which contains other comics writers such as Neil Gaiman and Alan Moore.


Nitrogen Retention And Denitrification In Reservoirs, Erin Grantz Dec 2011

Nitrogen Retention And Denitrification In Reservoirs, Erin Grantz

Graduate Theses and Dissertations

Studies coupling direct measurements of micro-scale nitrogen (N) cycle processes with ecosystem-scale flux estimates are needed to determine N retention hotspots within river networks, where up to 50% of terrestrial loading to aquatic systems is retained. This study examined the role of denitrification, a microbially-mediated reactive N removal pathway, in ecosystem-scale N retention in 3 small (< 1 km2), shallow flood-control reservoirs. Annual reservoir N retention was estimated through mass balance modeling of system inputs and outputs. Annual denitrification rates were estimated by combining multiple measurements of seasonal, habitat-specific dinitrogen gas (N2) fluxes. Annual reservoir N retention ranged from 14 - 19 g m-2 in the reservoirs, while reactive N removal through denitrification was 13 - 25 g m-2. Denitrification efficiency, or the portion of the retained N load that was denitrified, was high relative to other lentic systems and was > 100% at 2 sites. Previous lentic denitrification studies may have underestimated denitrification efficiency by not considering water column denitrification, which was 50% of total denitrification at one study reservoir. However, not all potential inputs, most importantly biological N2 fixation, were included in this …


Mathematically Gifted Students' Experiences Of Challenge With Cognitively Guided Instruction, Kim Krusen Mccomas Dec 2011

Mathematically Gifted Students' Experiences Of Challenge With Cognitively Guided Instruction, Kim Krusen Mccomas

Graduate Theses and Dissertations

This study examined to what extent and in what ways mathematically gifted students were challenged in two elementary classrooms taught by exemplary teachers using the principles of Cognitively Guided Instruction (CGI). The two case studies included a third grade class and a fourth/fifth split grade class, with five mathematically advanced participants from each grade. A top tier and a second tier of mathematically advanced students were identified, with the top tier of five students identified as mathematically gifted. Classroom observations of CGI math lessons, interviews with students and teachers, and analysis of students' problem-solving strategies were conducted over a five …


Modeling Of Sic P-Channel Insulated Gate Bipolar Transistors (Igbts), Mahmood Saadeh Dec 2011

Modeling Of Sic P-Channel Insulated Gate Bipolar Transistors (Igbts), Mahmood Saadeh

Graduate Theses and Dissertations

A new physics-based IGBT compact model has been developed for circuit simulation of silicon (Si) or silicon carbide (SiC) devices. The model accurately predicts the steady-state output, transfer and switching characteristics of the IGBT under a variety of different conditions. This is the first IGBT model to predict the behavior of p-channel SiC IGBTs. Previous work on IGBT models has focused on Si n-channel IGBTs [1-3]. This unified model is not limited to SiC p-channel IGBTs; the user has the option to select between Si or SiC, and n-channel or p-channel, making it the first IGBT model that captures the …


Geospatial Tools And Techniques For Watershed Management Using Swat 2009, Naresh Pai Dec 2011

Geospatial Tools And Techniques For Watershed Management Using Swat 2009, Naresh Pai

Graduate Theses and Dissertations

In this study, geospatial tools and techniques were developed to support specific aspects of watershed pollution management, such as quantifying land-use change (LUC) impacts, prioritizing subwatersheds, and communicating field-scale impacts, using the soil and water assessment tool 2009 (SWAT 2009) model.

For the land-use change objective, a geospatial tool titled SWAT2009_LUC was developed that enables SWAT modelers to prepare specific input files for simulating concurrent land-use changes during the SWAT 2009 model simulations. Testing of the tool for the Illinois River Drainage Area in Arkansas (IRDAA) watershed showed that the tool accurately represented temporal land-uses within the model. Model simulations …


Modeling And Characterization Of P-Type Silicon Carbide Gate Turn Off Thyristors, Osama Shihadeh Saadeh Dec 2011

Modeling And Characterization Of P-Type Silicon Carbide Gate Turn Off Thyristors, Osama Shihadeh Saadeh

Graduate Theses and Dissertations

Silicon carbide (SiC) power semiconductor devices have emerged in the past decade as the most promising technology for next generation power electronic applications ranging for electric vehicles to grid-connected power routing and conversion interfaces. Several devices have been developed, and even some have been released commercially, including diodes, MOSFETs, JFETs, thyristors, gate turn-off thyristors, and IGBTs. The model development, characterization and experimental validation of SiC p-type Gate Turn-off Thyristors (GTO) is presented in this work. The GTO device in this work is being used as part of a SiC-based solid-state fault current limiter under development at the University of Arkansas' …


Defining, Executing And Visualizing Representative Workflows In A Retail Domain, May Zeineldin Dec 2011

Defining, Executing And Visualizing Representative Workflows In A Retail Domain, May Zeineldin

Graduate Theses and Dissertations

Our lives are filled with routine activities that we do more or less on auto-pilot such as driving to work and cooking. This thesis explores a workflow representation as a way to represent such activities of daily living. The domain of a retail store environment is used. Workflows are initially expressed in a structured English representation, then translated into a Petri net notation and implemented in mix of Petri nets, Lua, and C so that the resulting workflows can be displayed as the actions of collections of avatarbots (avatars controlled by programs) in a 3D virtual world, Second Life. One …


Teaching In Educational Leadership Using Web 2.0 Applications: Perspectives On What Works, E. J. Shinsky, Hans A. Stevens Dec 2011

Teaching In Educational Leadership Using Web 2.0 Applications: Perspectives On What Works, E. J. Shinsky, Hans A. Stevens

Peer Reviewed Articles

To prepare 21st Century school leaders, educational leadership professors need to learn and teach the utilization of increasingly sophisticated technologies in their courses. The co-authors, a professor and an educational specialist degree candidate, describe how the use of advanced technologies — such as Wikis, Google Docs, Wimba Classroom, and Discussion Board — have served as a catalyst for learning among educational leadership students. Details regarding how technology has been used in one course are described, demonstrating how various apps and software applications can easily be applied in other courses.


Does Responding On Progressive Ratio Schedule Of Reinforcement Vary As A Function Of Phase In Estrous Cycle?, Armandina M. Sanchez Dec 2011

Does Responding On Progressive Ratio Schedule Of Reinforcement Vary As A Function Of Phase In Estrous Cycle?, Armandina M. Sanchez

Theses and Dissertations - UTB/UTPA

Hormonal fluctuations across the menstrual and estrous cycle have been found to influence a variety of behavioral and physical responses in humans and animals, respectively. Impulsive behavior has been associated with the luteal phase of the cycle. Progressive ratio schedule of reinforcement has been widely used to assess the strength of reinforcers. In the present study, a comparison was made between the rate of motor activity, lever pressing, of early and late estrous groups. Differences between the groups were not statistically significant. Further analysis explored subjects individually. Visual examination of the data reveal extreme variability in responding, which coupled with …