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1999

Physical Sciences and Mathematics

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17th International Herman F. Mark Symposium: Polypropylene - A Material Of The Future, Otto Vogl, Helga Roder Dec 1999

17th International Herman F. Mark Symposium: Polypropylene - A Material Of The Future, Otto Vogl, Helga Roder

Otto Vogl

No abstract provided.

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Dynamics Of A Gravitational Billiard With A Hyperbolic Lower Boundary, Matthew L. Ferguson, B. N. Miller, M. A. Thompson Dec 1999

Dynamics Of A Gravitational Billiard With A Hyperbolic Lower Boundary, Matthew L. Ferguson, B. N. Miller, M. A. Thompson

Matthew L. Ferguson

Gravitational billiards provide a simple method for the illustration of the dynamics of Hamiltonian systems. Here we examine a new billiard system with two parameters, which exhibits, in two limiting cases, the behaviors of two previously studied one-parameter systems, namely the wedge and parabolic billiard. The billiard consists of a point mass moving in two dimensions under the influence of a constant gravitational field with a hyperbolic lower boundary. An iterative mapping between successive collisions with the lower boundary is derived analytically. The behavior of the system during transformation from the wedge to the parabola is investigated for a few …

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Hopf Bifurcation In Models For Pertussis Epidemiology, Herbert W. Hethcote, Yi Li, Zhujun Jing Dec 1999

Hopf Bifurcation In Models For Pertussis Epidemiology, Herbert W. Hethcote, Yi Li, Zhujun Jing

Yi Li

Pertussis (whooping cough) incidence in the United States has oscillated with a period of about four years since data was first collected in 1922. An infection with pertussis confers immunity for several years, but then the immunity wanes, so that reinfection is possible. A pertussis reinfection is mild after partial loss of immunity, but the reinfection can be severe after complete loss of immunity. Three pertussis transmission models with waning of immunity are examined for periodic solutions. Equilibria and their stability are determined. Hopf bifurcation of periodic solutions around the endemic equilibrium can occur for some parameter values in two …

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Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole Dec 1999

Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole

UNLV Theses, Dissertations, Professional Papers, and Capstones

A 100 meter X 100 meter study site was chosen at White Rock Springs in Red Rock Canyon National Conservation Area, Nevada. To examine Syntrichia caninervis, a desert crustal moss, reciprocal transplantations (20 mm and 40 mm diameter cores) were performed between shaded to shaded, exposed to exposed, and shaded to exposed microsites to determine if it was possible to transplant the study organism with reasonable survivorship. Transplants were inspected following rain events for percent hydration, number of dead stems, and change in percent cover. Data indicated that there was a low mortality rate of S. caninervis stems, and few …

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Systemic Environmental Analysis Of The Legal Mechanisms For Controlling Air Pollution In The Las Vegas Valley, Richard Little Dec 1999

Systemic Environmental Analysis Of The Legal Mechanisms For Controlling Air Pollution In The Las Vegas Valley, Richard Little

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examines the air pollution control structure for the Las Vegas Valley. A System Dynamics computer model was created that represents the structure of the real world system for controlling air pollution, in order to examine how the current air pollution control system might behave in the future.

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Late Quaternary Fossil Mammals And Last Occurrence Dates From Caves At Barahona, Puerto Rico, Donald A. Mcfarlane Dec 1999

Late Quaternary Fossil Mammals And Last Occurrence Dates From Caves At Barahona, Puerto Rico, Donald A. Mcfarlane

WM Keck Science Faculty Papers

Puerto Rico supported at least five genera of endemic terrestrial mammals in the late Quaternary, all of which are extinct. Whether these animals died out in the late Pleistocene, the mid-Holocene, or in post-Columbian time has not been established. This paper is the first attempt at radiometrically dating the 'last occurrences' of these taxa, together with the first unambiguous descriptions of localities reported by previous workers. Last occurrence dates for Nesophontes, Elasmodontomys and Heteropsomys are shown to be mid-Holocene and overlap with Amerindian occupation of the island. Acratocnus is known only from the late Pleistocene. No Puerto Rican taxon has …

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Anneli Lax: In Memoriam, Elena Anne Corie Marchisotto Dec 1999

Anneli Lax: In Memoriam, Elena Anne Corie Marchisotto

Humanistic Mathematics Network Journal

No abstract provided.

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Teaching A Humanities Course: A Mathematician’S View, Bill Marion Dec 1999

Teaching A Humanities Course: A Mathematician’S View, Bill Marion

Humanistic Mathematics Network Journal

No abstract provided.

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Word Problems, Don Pfaff Dec 1999

Word Problems, Don Pfaff

Humanistic Mathematics Network Journal

No abstract provided.

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A Response To Dancis, Margaret Schaffer Dec 1999

A Response To Dancis, Margaret Schaffer

Humanistic Mathematics Network Journal

No abstract provided.

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Another Response To Dancis, Ted Eisenberg Dec 1999

Another Response To Dancis, Ted Eisenberg

Humanistic Mathematics Network Journal

No abstract provided.

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Evaluation In The Mathematics Classroom, Emam Hoosain, B. Naraine Dec 1999

Evaluation In The Mathematics Classroom, Emam Hoosain, B. Naraine

Humanistic Mathematics Network Journal

No abstract provided.

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What Is The Thing Called “Humanistic Mathematics?”, Tamar Apel Dec 1999

What Is The Thing Called “Humanistic Mathematics?”, Tamar Apel

Humanistic Mathematics Network Journal

No abstract provided.

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Mathematics Is An Art: The Story Of A One-Time Course, Paul Fjelstad Dec 1999

Mathematics Is An Art: The Story Of A One-Time Course, Paul Fjelstad

Humanistic Mathematics Network Journal

No abstract provided.

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A Reflection On The Word: Remembering The Word “Word” Is Reflexive, Paul Fjelstad, Ivan Ginchev Dec 1999

A Reflection On The Word: Remembering The Word “Word” Is Reflexive, Paul Fjelstad, Ivan Ginchev

Humanistic Mathematics Network Journal

No abstract provided.

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Calculus For The Liberal Arts: A Humanistic Approach, Kathleen Shannon Dec 1999

Calculus For The Liberal Arts: A Humanistic Approach, Kathleen Shannon

Humanistic Mathematics Network Journal

No abstract provided.

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Ode To Mathematics, Sandra Z. Keith Dec 1999

Ode To Mathematics, Sandra Z. Keith

Humanistic Mathematics Network Journal

No abstract provided.

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Excerpts From Ivan’S Commandments To Himself, Ivan Niven Dec 1999

Excerpts From Ivan’S Commandments To Himself, Ivan Niven

Humanistic Mathematics Network Journal

No abstract provided.

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Divisibility: A Problem Solving Approach Through Generalizing And Specializing, Rina Zazkis Dec 1999

Divisibility: A Problem Solving Approach Through Generalizing And Specializing, Rina Zazkis

Humanistic Mathematics Network Journal

No abstract provided.

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The Role Of Values In Mathematics Education, Murad Jurdak Dec 1999

The Role Of Values In Mathematics Education, Murad Jurdak

Humanistic Mathematics Network Journal

No abstract provided.

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Book Review: A Tour Of The Calculus By David Berlinski, Bernard Fleishman Dec 1999

Book Review: A Tour Of The Calculus By David Berlinski, Bernard Fleishman

Humanistic Mathematics Network Journal

No abstract provided.

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Book Review: Mathematical Reflections By Peter Hilton, Derek Holton And Jean Pedersen, Ladnor Geissinger Dec 1999

Book Review: Mathematical Reflections By Peter Hilton, Derek Holton And Jean Pedersen, Ladnor Geissinger

Humanistic Mathematics Network Journal

No abstract provided.

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Roots, Don Pfaff Dec 1999

Roots, Don Pfaff

Humanistic Mathematics Network Journal

No abstract provided.

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Tea Tasting And Pascal Triangles, Paul Alper, Yongzhi Yang Dec 1999

Tea Tasting And Pascal Triangles, Paul Alper, Yongzhi Yang

Humanistic Mathematics Network Journal

No abstract provided.

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Measurement Of TC Suppression In Tungsten Using Magnetic Impurities, Betty A. Young, T. Saab, Blas Cabrera, J. J. Cross, R. M. Clarke, R. A. Abusaidi Dec 1999

Measurement Of TC Suppression In Tungsten Using Magnetic Impurities, Betty A. Young, T. Saab, Blas Cabrera, J. J. Cross, R. M. Clarke, R. A. Abusaidi

Physics

We have measured the effects of dilute magnetic-atom doping on the superconducting transition temperature of tungsten thin films. Our “Tc tuning” technique is accurate, precise, and simple. Experiments were performed using dc-magnetron-sputtered tungsten films with undoped values of Tc in the range of 70–150 mK. The magnetic-atom doping was achieved using ion implantation. Specific Tc suppressions of between 5% and 65% were targeted and observed in this study. The transition width of each undoped sample was ≈1 mK and the transition widths remained sharp after implantation with 56Fe+ ions. Our data are in good agreement …

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Characterizations Of Classes Of Programs By Three-Valued Operators, Anthony K. Seda, Pascal Hitzler Dec 1999

Characterizations Of Classes Of Programs By Three-Valued Operators, Anthony K. Seda, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Several important classes of normal logic programs, including the classes of acyclic, acceptable, and locally hierarchical programs, have the property that every program in the class has a unique two-valued supported model. In this paper, we call such classes unique supported model classes. We analyse and characterize these classes by means of operators on three-valued logics. Our studies will motivate the definition of a larger unique supported model class which we call the class of Phi-accessible programs. Finally, we show that the class of Phi -accessible programs is computationally adequate in that every partial recursive function can be implemented by …

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Hopf Bifurcation In Models For Pertussis Epidemiology, Herbert W. Hethcote, Yi Li, Zhujun Jing Dec 1999

Hopf Bifurcation In Models For Pertussis Epidemiology, Herbert W. Hethcote, Yi Li, Zhujun Jing

Mathematics and Statistics Faculty Publications

Pertussis (whooping cough) incidence in the United States has oscillated with a period of about four years since data was first collected in 1922. An infection with pertussis confers immunity for several years, but then the immunity wanes, so that reinfection is possible. A pertussis reinfection is mild after partial loss of immunity, but the reinfection can be severe after complete loss of immunity. Three pertussis transmission models with waning of immunity are examined for periodic solutions. Equilibria and their stability are determined. Hopf bifurcation of periodic solutions around the endemic equilibrium can occur for some parameter values in two …

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Self-Consistency Algorithms, Thaddeus Tarpey Dec 1999

Self-Consistency Algorithms, Thaddeus Tarpey

Mathematics and Statistics Faculty Publications

The k-means algorithm and the principal curve algorithm are special cases of a self-consistency algorithm. A general self-consistency algorithm is described and results are provided describing the behavior of the algorithm for theoretical distributions, in particular elliptical distributions. The results are used to contrast the behavior of the algorithms when applied to a theoretical model and when applied to finite datasets from the model. The algorithm is also used to determine principal loops for the bivariate normal distribution.

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Year In Review - 1999, Annis Water Resources Institute Dec 1999

Year In Review - 1999, Annis Water Resources Institute

AWRI Reviews

No abstract provided.

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Towards The Evaluation Of Netcentric Scientific Applications, Shanhani Markus, Elias N. Houstis Dec 1999

Towards The Evaluation Of Netcentric Scientific Applications, Shanhani Markus, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

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