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1998

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Articles 4921 - 4950 of 6048

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Environmental Stress Effects On Vigor, Mortality, And Growth In Northern Hardwood Forests Along A Pollution-Climate Gradient, Neil W. Macdonald, John A. Witter, David R. Reed, Andrew J. Burton, Kurt S. Pregitzer, Hal O. Liechty Jan 1998

Environmental Stress Effects On Vigor, Mortality, And Growth In Northern Hardwood Forests Along A Pollution-Climate Gradient, Neil W. Macdonald, John A. Witter, David R. Reed, Andrew J. Burton, Kurt S. Pregitzer, Hal O. Liechty

Peer Reviewed Publications

Concern exists over the effects of interacting environmental stresses on the ecological integrity of temperate forests. Coincidence of sensitivity to drought, increasing occurrence of defoliation, and elevated pollutant deposition has produced speculation that northern hardwood forests may be susceptible to the increased climatic stresses projected for the Great Lakes region. The objective of our study was to examine relationships among environmental stress factors, vigor, mortality, and growth in northern hardwood forests located along a pollution-climate gradient in the Great Lakes region. Between 1987 and 1993, we quantified climatic variables, pollutant deposition, insect defoliation, and tree vigor and growth at five …

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Washington University Magazine And Alumni News, Summer 1998 Jan 1998

Washington University Magazine And Alumni News, Summer 1998

Washington University Magazine

No abstract provided.

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Salute To Faculty Scholarship 1998, Clark University Jan 1998

Salute To Faculty Scholarship 1998, Clark University

Faculty Works

No abstract provided.

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Development And Saw Device Implementation Of A New Weighted Stepped Chirp Code Signal For Direct Sequence Spread Spectrum Communications Systems, Scott Edward Carter Jan 1998

Development And Saw Device Implementation Of A New Weighted Stepped Chirp Code Signal For Direct Sequence Spread Spectrum Communications Systems, Scott Edward Carter

Retrospective Theses and Dissertations

This work introduces the new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudonoise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to possess improved compression ratio (CR), peak sidelobe level (PSL), integrated sidelobe level (ISL), and bit error rate (BER) when compared to a PN code of identical code length and …

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Crevasse Patterns And The Strain-Rate Tensor: A High-Resolution Comparison, Joel T. Harper, Neil Humphrey, W. Tad Pfeffer Jan 1998

Crevasse Patterns And The Strain-Rate Tensor: A High-Resolution Comparison, Joel T. Harper, Neil Humphrey, W. Tad Pfeffer

Geosciences Faculty Publications

Values of the strain-rate tensor represented at a 20 m length scale are found to explain the pattern and orientation of crevasses in a 0.13 km2 reach of Worthington Glacier, Alaska, U.S.A. The flow field of the reach is constructed from surveyed displacements of 110 markers spaced 20-30 m apart. A velocity gradient method is then used to calculate values of the principal strain-rate axes at the nodes of a 20 m x 20 m orthogonal grid. Crevasses in the study reach are of two types, splaying and transverse, and are everywhere normal to the trajectories of greatest (most …

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Frequency Modulated Excitation Of A Two-Level Atom, Michael W. Noel, W. M. Griffith, T. F. Gallagher Jan 1998

Frequency Modulated Excitation Of A Two-Level Atom, Michael W. Noel, W. M. Griffith, T. F. Gallagher

Physics Faculty Research and Scholarship

We present a detailed experimental study of the frequency-modulated excitation of a two-level atom, using a microwave field to drive transitions between two Rydberg Stark states of potassium. In the absence of a modulation the interaction is the standard model of the Rabi problem, producing sinusoidal oscillations of the population between the two states. In the presence of a frequency modulation of the interacting field, however, the time evolution of the system is significantly modified, producing square wave oscillations of the popula- tion, sinusoidal oscillations at a different frequency, or even sinusoidal oscillations built up in a series of stair …

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Phase And Risetime Dependence Using Rf Pulses In Multiphoton Processes, W. M. Griffith, Michael W. Noel, T. F. Gallagher Jan 1998

Phase And Risetime Dependence Using Rf Pulses In Multiphoton Processes, W. M. Griffith, Michael W. Noel, T. F. Gallagher

Physics Faculty Research and Scholarship

With this experiment we demonstrate that excitation of a two-state system with radio-frequency fields differing in phase by 90° produces nonintuitively different results, even for very long pulses. In addition, we show how the phase dependence of the transition probability of long pulses can be easily understood by using the single cycle time propagator. Finally, we have found surprising results for real pulses in the strong-field regime, i.e., pulses having appreciable rise and fall times.

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Correcting Turnover Correlations: A Critique, Chuck R. Williams, L. H. Peters Jan 1998

Correcting Turnover Correlations: A Critique, Chuck R. Williams, L. H. Peters

Scholarship and Professional Work - Business

In this article, the authors argue that turnover correlations do not need to be corrected. First, they maintain that correction formulas cannot correct for poor construct validity. Second, they discuss the original purposes of turnover correction formulas. Third, the authors describe the logical fallacies of correcting turnover correlations. Finally, they show why turnover correlations are not, as is widely believed, statistically limited to a maximum of .80.

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Recent Developments In Modern Finance, Subroto Roy Jan 1998

Recent Developments In Modern Finance, Subroto Roy

IIMB Management Review

While it has become commonplace to speak of whirlwind changes in global financial markets, the lay investor is often faced with mysterious new terms without being given an adequate description of the concepts behind them. An attempt has been made to demystify some of the myths and mysteries connected with these developments.

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A Longitudinal Study Of Engineering Student Performance And Retention. V. Comparisons With Traditionally-Taught Students, Richard M. Felder, Gary Felder, E. Jacquelin Dietz Jan 1998

A Longitudinal Study Of Engineering Student Performance And Retention. V. Comparisons With Traditionally-Taught Students, Richard M. Felder, Gary Felder, E. Jacquelin Dietz

Physics: Faculty Publications

In a longitudinal study at North Carolina State University, a cohort of students took five chemical engineering courses taught by the same instructor in five consecutive semesters. The courses made extensive use of active and cooperative learning and a variety of other techniques designed to address a broad spectrum of learning styles. Previous reports on the study summarized the instructional methods used in the experimental course sequence, described the performance of the cohort in the introductory chemical engineering course, and examined performance and attitude differences between students from rural and urban backgrounds and between male and female students.1–4 This paper …

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Stability And Weight Smoothing In Cmac Neural Networks, David Paul Campagna Jan 1998

Stability And Weight Smoothing In Cmac Neural Networks, David Paul Campagna

Doctoral Dissertations

Although the CMAC (Cerebellar Model Articulation Controller) neural network has been successfully used in control systems for many years, its property of local generalization, the availability of trained information for network responses at adjacent untrained locations, although responsible for the networks rapid learning and efficient implementation, results in network responses that is, when trained with sparse or widely spaced training data, spiky in nature even when the underlying function being learned is quite smooth. Since the derivative of such a network response can vary widely, the CMAC's usefulness for solving optimization problems as well as for certain other control system …

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Generalized Inverse Estimator And Comparison With Least Squares Estimator, S. Sakallıoğlu, F. Akdeniz Jan 1998

Generalized Inverse Estimator And Comparison With Least Squares Estimator, S. Sakallıoğlu, F. Akdeniz

Turkish Journal of Mathematics

Trenkler [13] described an iteration estimator. This estimator is defined as follows: for $0 < \gamma < 1/\lambda_i \max$ \[ \hat{\beta}_{m, \gamma} = \gamma \sum^m_{i=0} (1-\gamma X'X)^i X'y , \] where $\lambda_i$ are eigenvalues of $X'X$. In this paper a new estimator (generalized inverse estimator) is introduced based on the results of Tewarson [11]. A sufficient condition for the difference of mean square error matrices of least squares estimator and generalized inverse estimator to be positive definite (p.d.) is derived.

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The Acute Effects Of A Single Bout Of Resistance Training On Postural Control In The Elderly, Justin Brian Moore Jan 1998

The Acute Effects Of A Single Bout Of Resistance Training On Postural Control In The Elderly, Justin Brian Moore

Electronic Theses and Dissertations

No abstract provided.

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Holmes And The Romantic Mind, Anne Dailey Jan 1998

Holmes And The Romantic Mind, Anne Dailey

Faculty Articles and Papers

No abstract provided.

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Living Arrangements Of The Elderly In The United States: Comparing Whites, Blacks, Hispanics, And Asians' Households., Kiyomi Ando Jan 1998

Living Arrangements Of The Elderly In The United States: Comparing Whites, Blacks, Hispanics, And Asians' Households., Kiyomi Ando

LSU Historical Dissertations and Theses

My dissertation analyzed the living arrangements of the elderly, focusing on differences across gender and racial/ethnic lines. Drawing upon rational choice and family solidarity theoretical perspectives. I derived hypotheses dealing with the effects of individual resources, cultural characteristics, and geographic context on the elderly's living arrangements. These hypotheses were empirically tested using logistic regression models to estimate the odds of the elderly choosing from among three options of living arrangements--independent living, joint living, and dependent living. Separate models were applied to non-Hispanic white, African American, Hispanic, and Asian subsamples. Data were from the 1990 Census Public Use Sample (PUMS-L). The …

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Temporal Variation In Larval Fish Condition Indices., Michael John Burger Jan 1998

Temporal Variation In Larval Fish Condition Indices., Michael John Burger

LSU Historical Dissertations and Theses

A sensitive methodology for the determination of RNA and DNA concentrations was developed which allowed for the quantification of nanogram amounts of both DNA and RNA. The method uses a combination of thiazole orange, a non-specific nucleic acid stain, and the RNA degrading enzyme RNase. Thiazole orange had high fluorescence yield. The fluorescence was additive for combinations of RNA and DNA. The addition of proteinase-K increased the fluorescence of the tissue sample by 100%. Recovery of nucleic acid standards added to tissue extracts yielded $\sim$100% recovery. The method is compatible with assays for protein concentration and electron transport system (ETS) …

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Assessing Applicant "Fit" Within The Selection Process: Which Interviewer Perceptions Matter?, Dawn Ebe Haptonstahl Jan 1998

Assessing Applicant "Fit" Within The Selection Process: Which Interviewer Perceptions Matter?, Dawn Ebe Haptonstahl

LSU Historical Dissertations and Theses

The research literature has noted that organizations are moving beyond simply hiring individuals with the necessary knowledge, skills, and abilities (KSAs) that fulfill the requirements of the job--employers are also looking for people who can fit in with a particular work group or even an entire organization. This study tested an exploratory model that predicted recruiter selection decisions from their evaluations of applicants' person-job (P-J), person-group (P-G), and person-organization (P-O) fit. The model also postulated that P-G and P-O fit would be predicted by the perceived congruence (similarity) of work values between applicants and groups/organizations, Hypotheses were field-tested with 64 …

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The Clarity Of The Modern: Or, The Ambiguities Of Henry James And Wallace Stevens., Gregory Angelo Marks Jan 1998

The Clarity Of The Modern: Or, The Ambiguities Of Henry James And Wallace Stevens., Gregory Angelo Marks

LSU Historical Dissertations and Theses

Clarity, in all its various guises, was before the advent of Romanticism looked upon as an unquestioned focus of attention and irrefutable goal of human endeavor. Conversely, ambiguity was seen negatively: it was in language an obstacle to communication; in ethics, an indecisiveness failing action; and in ontology and aesthetics, a slovenly disorder. With Romanticism, this basic consensus regarding these terms ends. No longer an expression of censure, ambiguity is imagined as a liberatory force. Clarity, if attainable at all, is dismissed as mere rigidity. The works of Americans Henry James and Wallace Stevens embody and enact this tension and …

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The Socialization Of Indian Scientific Writers Into Western Scientific Discourse Communities., Sumita Roy Jan 1998

The Socialization Of Indian Scientific Writers Into Western Scientific Discourse Communities., Sumita Roy

LSU Historical Dissertations and Theses

This research studies the socialization of Indian science writers into western discourse communities. More specifically, it seeks to identify the writing problems that beginner Indian science writers face and the strategies that they adopt in overcoming them while writing dissertations or research articles. Primary information was gathered by interviewing 11 Indian graduate students and 17 faculty members from India (West Bengal) and the USA on the basis of a five-page questionnaire. Respondents were classified into three groups according to their places of training and writing skills. Three to five sets of rough drafts from each group were studied to note …

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Development Of A Quantitative Polymerase Chain Reaction Procedure For Analysis Of Cytokine Responses To Strongylus Vulgaris In Ponies., Cyprianna Ellen Swiderski Jan 1998

Development Of A Quantitative Polymerase Chain Reaction Procedure For Analysis Of Cytokine Responses To Strongylus Vulgaris In Ponies., Cyprianna Ellen Swiderski

LSU Historical Dissertations and Theses

The effect of oral vaccination with radiation-attenuated Strongylus vulgaris larvae on the cytokine responses of ponies to oral challenge with S. vulgaris was examined. Message was quantified using RT-PCR by interpolation against a plasmid-derived standard curve. PCR product was detected using the Perkin-Elmer QPCR System 5000. Standard curves were analyzed with a two parameter exponential rise to maximum fit of the data. By altering the cycling parameters to maintain $\beta$-actin amplification within its exponential phase, $\beta$-actin was used as a normalization factor. The assay resolves 2 fold changes in message, has a linear dynamic range on the order of 3 …

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On The Second Stiefel-Whitney Class Of Scaled Trace Forms Of Central Simple Algebras., Rosali Brusamarello Jan 1998

On The Second Stiefel-Whitney Class Of Scaled Trace Forms Of Central Simple Algebras., Rosali Brusamarello

LSU Historical Dissertations and Theses

In this work we compute the second Stiefel-Whitney class $w\sb2$ of the scaled trace form $Q\sb{A,a}(x)={\bf tr}\sb{A/k}(ax\sp2),$ where A is a central simple algebra over a perfect field k of characteristic different from two, $a\in A$ is a fixed element, and ${\bf tr}\sb{A/k}$ is the reduced trace. The first three chapters provide background material about quadratic forms, central simple algebras, group cohomology, and representations of linear algebraic groups. The fourth chapter presents two known results about the second Stiefel-Whitney class of trace forms: Serre's formula for the case of etale algebras and Saltman's formula for the case of central simple …

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Using Mathematical Modeling For The Prediction Of Success In Developmental Math., Kathy Rogers Autrey Jan 1998

Using Mathematical Modeling For The Prediction Of Success In Developmental Math., Kathy Rogers Autrey

LSU Historical Dissertations and Theses

This exploratory study was primarily designed to determine the possibility of developing a discriminant model to predict success in developmental mathematics. The sample included 402 students enrolled in a developmental math class at Northwestern State University, a small public school in North Louisiana, in the fall semester of 1996. Demographic, achievement and attitudinal variables were used in the development of the model. High school GPA, social enrichment scores from the College Student Inventory, and black were factors identified as significant in the model. Although limited in its predictive ability, the model does provide faculty and advisors with additional information to …

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Using Academic And Demographic Variables To Predict Success In The General Education Curriculum., Steven Giles Horton Jan 1998

Using Academic And Demographic Variables To Predict Success In The General Education Curriculum., Steven Giles Horton

LSU Historical Dissertations and Theses

Student success and attrition in all levels of education is becoming a more important issue in an age where education dollars are diminishing while various schools of higher learning are increasing. As a result, schools are reevaluating their current programs of study in an attempt to determine if both students and universities are fulfilling their respective goals. This process of reevaluation has several fundamental considerations, one of these which is addressed in this study--the effectiveness of prerequisite requirements and other demographic variables on predicting the success of students in courses in the general education curriculum. The purpose of this study, …

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Clinical Laboratory Science University Faculty Learning Types And The Use Of Information Technology In The Classroom., Cynthia Susan Handley Jan 1998

Clinical Laboratory Science University Faculty Learning Types And The Use Of Information Technology In The Classroom., Cynthia Susan Handley

LSU Historical Dissertations and Theses

This study was designed to explore the status of learning types of clinical laboratory science university faculty and their use of information technology in the classroom. Traditionally clinical laboratory science education has been lecture and lab sessions. However, with the advent of the information age, professors are moving from the role of lecturer to facilitator. Some professors are in tune with the new information tools while others are not interested at all. This research had a two-fold purpose: (1) to explore who was using technology in the classroom and identify what they were using, and (2) to search for a …

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Sample-Based Forest Landscape Diversity Indices., Bernard Ross Parresol Jan 1998

Sample-Based Forest Landscape Diversity Indices., Bernard Ross Parresol

LSU Historical Dissertations and Theses

Studies of spatial patterns of landscapes are useful to quantify human impact, predict wildlife effects, or describe various landscape features. A robust landscape index should quantify two distinct components of landscape diversity: composition and configuration. One category of landscape index is the contagion index. A generalized measure of contagion is defined as a function of concentration. From this definition two contagion indices, $\Gamma\sb1$ (a new index) and $\Gamma\sb2$ (an entropy formulation), are derived from expected values of geometric random variables. A widely used relative contagion index, $RC\sb2,$ is shown to be a scaled version of $\Gamma\sb2.$. Distributional properties of $\\Gamma\sb1,\ …

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The Current Status Of Four-Year Undergraduate Construction Education Programs In The United States., Lawrence Leslie Rosso Jan 1998

The Current Status Of Four-Year Undergraduate Construction Education Programs In The United States., Lawrence Leslie Rosso

LSU Historical Dissertations and Theses

The objectives of this study were to describe selected program, curriculum, student, and faculty characteristics, and to explore bivariate relationships between selected pairs of variables within these categories. The review of literature encompassed: general curriculum development and philosophy; American Council for Construction Education, Accreditation Board for Engineering and Technology, and National Association of Industrial Technology accreditation agencies program philosophies and criteria; and past studies related to programs, faculty, and graduates. The methodology included: a survey of 156 programs; a 26 item survey mailed questionnaire; two follow-up postcards and a follow-up telephone call to all non-respondents; and a facsimile to 25 …

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Autobiography From St. Augustine To David Antin: Examining The Construction Of The Self As Mutually Reflective Of Cultural Developments In Science And Technology, Art, And Literary Theory., Jessica Lynn Faust Jan 1998

Autobiography From St. Augustine To David Antin: Examining The Construction Of The Self As Mutually Reflective Of Cultural Developments In Science And Technology, Art, And Literary Theory., Jessica Lynn Faust

LSU Historical Dissertations and Theses

In this study, I look at the mutually reflective changes in society and autobiography in works definitive for their various periods: Augustine's The Confessions from antiquity; Rousseau's The Confessions from the eighteenth century; the autobiographical writings of Gertrude Stein, from the modernist period; and, most importantly here, the focus on the development of David Antin's work as representative of both postmodernism and current culture. Specifically, I consider the construction of the self in respect to art, literary theory, memory research, and science and technology. During the second half of the twentieth century, computers have permeated almost every facet of society. …

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A Study Of Pore Fluids And Barite Deposits From Hydrocarbon Seeps: Deepwater Gulf Of Mexico., Baoshun Fu Jan 1998

A Study Of Pore Fluids And Barite Deposits From Hydrocarbon Seeps: Deepwater Gulf Of Mexico., Baoshun Fu

LSU Historical Dissertations and Theses

The primary goals of this research were to (i) determine the factors controlling the chemical compositions of pore fluids in hydrocarbon seep sediments of the Gulf of Mexico, and (ii) delineate the nature, age and origin of barite deposits associated with seeps. Three types of pore fluids from seeps have been discerned: (i) sediment-trapped seawater; (ii) brines derived by seawater dissolution of subsurface salt diapirs; and (iii) deep-seated formation waters enriched in Ba and Ra. The Ra-enriched formation waters advecting to the seafloor may explain why 226Ra levels in the Gulf of Mexico water column are higher than in the …

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The Psychometric Characteristics Of The Adhd Rating Scale-Iv., George Walter Hebert Jan 1998

The Psychometric Characteristics Of The Adhd Rating Scale-Iv., George Walter Hebert

LSU Historical Dissertations and Theses

The ADHD Rating Scale-IV is a screening instrument designed to assess attention-deficit/hyperactivity disorder in children. It is comprised of 18 items and has both a home and school version for parents and teachers to complete, respectively. A sample consisting of 178 parent-teacher dyads of children aged 6-12 years of age participated in the study. Psychometric investigation of these scales revealed high internal consistency, adequate test-retest reliability, and appropriate correlations with other measures of ADHD. Principal components factor analysis revealed two factors for both scales: (1) Inattention-hyperactivity and (2) Impulsivity-hyperactivity. Discriminant function analyses and base rate analyses revealed that these scales …

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Spikes In Matroid Theory., Zhaoyang Wu Jan 1998

Spikes In Matroid Theory., Zhaoyang Wu

LSU Historical Dissertations and Theses

For an integer $n\ge 3,$ a rank-n matroid is called an n-spike if it consists of n three-point lines through a common point t such that, for all k in $(1, 2,\..., n - 1),$ the union of every set of k of these Lines has rank $k + 1.$ The point t is called the tip of the n-spike. Ding, Oporowski, Oxley, and Vertigan proved that, for all $n\ge 3,$ there is an integer $N(n)$ such that every 3-connected matroid with at least $N(n)$ elements has a minor isomorphic to a wheel or whirl of rank $n,\ M(K\sb{3,n})$ or …

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