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Articles 1861 - 1890 of 2640

Full-Text Articles in Physical Sciences and Mathematics

Special Section: On The Publication Of The 26th Issue Of The Humanistic Mathematics Network Journal, Sandra Z. Keith Jun 2002

Special Section: On The Publication Of The 26th Issue Of The Humanistic Mathematics Network Journal, Sandra Z. Keith

Humanistic Mathematics Network Journal

No abstract provided.


Does A Mathematical/Scientific Worldview Lead To A Clearer Or More Distorted View Of Reality?: Purposive Musings Inspired From Readings In The Urantia Book, The Cosmic Family, Volume I, And Elsewhere, Jeru Jun 2002

Does A Mathematical/Scientific Worldview Lead To A Clearer Or More Distorted View Of Reality?: Purposive Musings Inspired From Readings In The Urantia Book, The Cosmic Family, Volume I, And Elsewhere, Jeru

Humanistic Mathematics Network Journal

No abstract provided.


Teaching As Though Students Mattered: A Biography Of Alvin White As Told To Sandra Keith, Alvin White, Sandra Z. Keith Jun 2002

Teaching As Though Students Mattered: A Biography Of Alvin White As Told To Sandra Keith, Alvin White, Sandra Z. Keith

Humanistic Mathematics Network Journal

No abstract provided.


Humanistic Mathematics: Personal Evolution And Excavations, Stephen I. Brown Jun 2002

Humanistic Mathematics: Personal Evolution And Excavations, Stephen I. Brown

Humanistic Mathematics Network Journal

No abstract provided.


Letters And Comments, Issue 26, 2002, Dick Tahta Jun 2002

Letters And Comments, Issue 26, 2002, Dick Tahta

Humanistic Mathematics Network Journal

No abstract provided.


Nonlinear Dynamics Of Mode-Locking Optical Fiber Ring Lasers, Kristin M. Spaulding, Darryl H. Yong, Arnold D. Kim, J Nathan Kutz May 2002

Nonlinear Dynamics Of Mode-Locking Optical Fiber Ring Lasers, Kristin M. Spaulding, Darryl H. Yong, Arnold D. Kim, J Nathan Kutz

All HMC Faculty Publications and Research

We consider a model of a mode-locked fiber ring laser for which the evolution of a propagating pulse in a birefringent optical fiber is periodically perturbed by rotation of the polarization state owing to the presence of a passive polarizer. The stable modes of operation of this laser that correspond to pulse trains with uniform amplitudes are fully classified. Four parameters, i.e., polarization, phase, amplitude, and chirp, are essential for an understanding of the resultant pulse-train uniformity. A reduced set of four coupled nonlinear differential equations that describe the leading-order pulse dynamics is found by use of the variational nature …


A Stirling Encounter With Harmonic Numbers, Arthur T. Benjamin, Gregory O. Preston '01, Jennifer J. Quinn Apr 2002

A Stirling Encounter With Harmonic Numbers, Arthur T. Benjamin, Gregory O. Preston '01, Jennifer J. Quinn

All HMC Faculty Publications and Research

No abstract provided in this article.


Four-Person Envy-Free Chore Division, Elisha Peterson '00, Francis E. Su Apr 2002

Four-Person Envy-Free Chore Division, Elisha Peterson '00, Francis E. Su

All HMC Faculty Publications and Research

No abstract provided in this article


Mixed Partial Derivatives And Fubini's Theorem, Asuman Güven Aksoy, Mario Martelli Mar 2002

Mixed Partial Derivatives And Fubini's Theorem, Asuman Güven Aksoy, Mario Martelli

CMC Faculty Publications and Research

A most fascinating aspect of calculus is its power to surprise even an experienced mathemat ician. Just when it appears that all ideas, results and connections have been discovered and thorough ly analyzed, the horizon suddenly broadens and somebody cries the familiar "eureka". The reason could be either a new result, a simpler way to prove an existing theorem, or a previously missed connection between different ideas. This potential for enrichment is second to none, and it reaffirms the unparalleled educational value of this area of mathematics.


Observation Of Anomalous Spin-State Segregation In A Trapped Ultracold Vapor, Dwight L. Whitaker, H. J. Lewandowski, D. M. Harber, E. A. Cornell Jan 2002

Observation Of Anomalous Spin-State Segregation In A Trapped Ultracold Vapor, Dwight L. Whitaker, H. J. Lewandowski, D. M. Harber, E. A. Cornell

Pomona Faculty Publications and Research

We observe counterintuitive spin segregation in an inhomogeneous sample of ultracold, noncondensed rubidium atoms in a magnetic trap. We use spatially selective microwave spectroscopy to verify a model that accounts for the differential forces on two internal spin states. In any simple understanding of the cloud dynamics, the forces are far too small to account for the dramatic transient spin polarizations observed. The underlying mechanism remains to be elucidated.


A New Megalonychid Sloth From The Late Wisconsinan Of The Dominican Republic, Elizabeth Rega, Donald A. Mcfarlane, Joyce Lundberg, Keith Christenson Jan 2002

A New Megalonychid Sloth From The Late Wisconsinan Of The Dominican Republic, Elizabeth Rega, Donald A. Mcfarlane, Joyce Lundberg, Keith Christenson

WM Keck Science Faculty Papers

An unusually well preserved skull, mandible, and indisputably associated post-cranial elements of new sloth, Acratocnus (Miocnus), were recovered from a cave in Jaragua National Park, Dominican Republic. The animal died lying in a rimstone pool and was rapidly coated with a thin calcite patina. We have documented a late Wisconsinan age for this specimen by inorganic 14C radiometric dating of the patina, with supporting data on the carbon systematics of the speleothems in this cave. This sloth is described as a new species on the basis of the distinctive morphology and relative size of cranial and mandibular features. We consider …


A Middle Pleistocene Age And Biogeography For The Extinct Rodent Megalomys Curazensis From Curaçao, Netherlands Antilles, Donald A. Mcfarlane, Joyce Lundberg Jan 2002

A Middle Pleistocene Age And Biogeography For The Extinct Rodent Megalomys Curazensis From Curaçao, Netherlands Antilles, Donald A. Mcfarlane, Joyce Lundberg

WM Keck Science Faculty Papers

The extinct oryzomyine rodent Megalomys curazensis has been known from abundant but fragmentary remains on the island of Curaçao since 1959. Here we demonstrate an age of 130 000 to 400 000 years before present based on geomorphological context, and propose a biogeographical model for the genus.


A Late Quaternary Paleoecological Record From Caves Of Southern Jamaica, West Indies, Donald A. Mcfarlane, Joyce Lundberg, A.G. Fincham Jan 2002

A Late Quaternary Paleoecological Record From Caves Of Southern Jamaica, West Indies, Donald A. Mcfarlane, Joyce Lundberg, A.G. Fincham

WM Keck Science Faculty Papers

Studies of an unusual and diverse system of caves in coastal southern Jamaica have yielded a paleoclimatic record associated with a fossil vertebrate record that provides useful insights into the poorly documented paleoecology of latest Wisconsinan and Holocene Jamaica. Episodes of significantly increased precipitation during the Holocene have left characteristic deposits of speleothems, and have supported both faunal and archaeological communities that were dependent on these mesic conditions. Deposits of fossil bat guano preserved in the caves provide a δ¹³C record of alternating mesic and xeric climatic episodes that supports the interpretation of the faunal and archaeological record.


Theoretical Investigation Of The Ground And Excited States Of Coumarin 151 And Coumarin 120, Robert J. Cave, Kieron Burke, Edward W. Castner Jr. Jan 2002

Theoretical Investigation Of The Ground And Excited States Of Coumarin 151 And Coumarin 120, Robert J. Cave, Kieron Burke, Edward W. Castner Jr.

All HMC Faculty Publications and Research

We present calculations of various properties of the ground and excited states of Coumarins 151 and 120. These and related coumarins are important in investigating ultrafast solvation processes in liquids and complex solutions as well as being important acceptors in model electron-transfer systems. We calculate the following:  (1) the electronic excitation energies to several low-lying singlet states, (2) ground and excited-state dipole moments, (3) solvation effects on excitation energies, and (4) the properties of single Coumarin 151-water complexes. We test our Time-Dependent Density Functional Theory (TDDFT) calculations against CASSCF, CASPT2 (both single and multistate versions), CIS, and ZINDO. Using TDDFT, …


Multistate Effects In Calculations Of The Electronic Coupling Element For Electron Transfer Using The Generalized Mulliken−Hush Method, Michael Rust '01, Jason Lappe '00, Robert J. Cave Jan 2002

Multistate Effects In Calculations Of The Electronic Coupling Element For Electron Transfer Using The Generalized Mulliken−Hush Method, Michael Rust '01, Jason Lappe '00, Robert J. Cave

All HMC Faculty Publications and Research

A simple diagnostic is developed for the purpose of determining when a third state must be considered to calculate the electronic coupling element for a given pair of diabatic states within the context of the generalized Mulliken−Hush approach (Chem. Phys. Lett. 1996, 275, 15−19). The diagnostic is formulated on the basis of Löwdin partitioning theory. In addition, an effective 2-state GMH expression is derived for the coupling as it is modified by the presence of the third state. Results are presented for (i) a model system involving charge transfer from ethylene to methaniminium cation, (ii) a …


Enumeration Of Matchings In The Incidence Graphs Of Complete And Complete Bipartite Graphs, Nicholas Pippenger Jan 2002

Enumeration Of Matchings In The Incidence Graphs Of Complete And Complete Bipartite Graphs, Nicholas Pippenger

All HMC Faculty Publications and Research

If G = (V, E) is a graph, the incidence graphI(G) is the graph with vertices I E and an edge joining vV and eE when and only when v is incident with e in G. For G equal to Kn (the complete graph on n vertices) or Kn,n (the complete bipartite graph on n + n vertices), we enumerate the matchings (sets of edges, no two having a vertex in common) in I(G), both exactly (in terms of generating …


Women In Physics In The United States, Megan Urry, Sheila Tobias, Kim Budil, Howard Georgi, Kristine Lang, Dongqi Li, Laurie Mcneil, Peter N. Saeta, Jennifer Sokoloski, Sharon Stephenson, Aparna Venkatesan, Yevgeniya Zastavker Jan 2002

Women In Physics In The United States, Megan Urry, Sheila Tobias, Kim Budil, Howard Georgi, Kristine Lang, Dongqi Li, Laurie Mcneil, Peter N. Saeta, Jennifer Sokoloski, Sharon Stephenson, Aparna Venkatesan, Yevgeniya Zastavker

All HMC Faculty Publications and Research

Presents an overview of the status of women in physics in the U.S. Under-representation of women; Highlights of the report 'Women in Physics, 2000'; Efforts to increase the number of women in the profession; Issues for women activists.


The Large M Limit Of Non-Commutative Open Strings At Strong Coupling, Vatche Sahakian Jan 2002

The Large M Limit Of Non-Commutative Open Strings At Strong Coupling, Vatche Sahakian

All HMC Faculty Publications and Research

Two-dimensional Non-Commutative Open String (NCOS) theory, well-defined perturbatively, may also be studied at strong coupling and for large D-string charge by making use of the Holographic duality. We analyze the zero mode dynamics of a closed string in the appropriate background geometry and map the results onto a sector of strongly coupled NCOS dynamics. We find an elaborate classical picture that shares qualitative similarities with the SL(2,R) WZW model. In the quantum problem, we compute propagators and part of the energy spectrum of the theory; the latter involves interesting variations in the density of states as a function …


Article Are Hydrogen Bonds Unique Among Weak Interactions In Their Ability To Mediate Electronic Coupling?, Emily Cukier '03, Sarah Daniels '02, Eric Vinson '01, Robert J. Cave Jan 2002

Article Are Hydrogen Bonds Unique Among Weak Interactions In Their Ability To Mediate Electronic Coupling?, Emily Cukier '03, Sarah Daniels '02, Eric Vinson '01, Robert J. Cave

All HMC Faculty Publications and Research

Superexchange effects on the electronic coupling element for electron transfer are investigated using water dimers and atomic donors and acceptors. We compare the electronic coupling elements obtained with H-bonded dimers to those obtained for other water dimer geometries at given donor−acceptor and oxygen−oxygen distances. The H-bonded orientation does not yield significantly different coupling elements from non-H-bonded orientations at a given oxygen−oxygen distance. In addition, the distance dependence of the coupling mediated by H-bonds is not significantly different from that for other dimer geometries. It is found that protonation of the intervening waters has a significant effect on coupling elements for …


Time-Dependent Density Functional Theory Investigation Of The Ground And Excited States Of Coumarins 102, 152, 153, And 343, Robert J. Cave, Edward W. Castner Jr. Jan 2002

Time-Dependent Density Functional Theory Investigation Of The Ground And Excited States Of Coumarins 102, 152, 153, And 343, Robert J. Cave, Edward W. Castner Jr.

All HMC Faculty Publications and Research

We present calculations of various properties of the ground and excited electronic states of coumarins 102, 152, 153, and 343. Using density functional theory (DFT) and time-dependent density functional theory (TDDFT), we examine the excitation energies to the S1 and S2 states, the ground and excited-state dipole moments, and the lowest ionization potentials of these coumarins. In the case of C153, we locate two distinct S0 minima due to differing conformations of the julolidyl ring structure and compare properties for the syn and anti conformers. For C343, we examine the possibility of proton transfers in the ground …


A Minimal Regular Ring Extension Of C(X), Melvin Henriksen, Robert M. Raphael, R. G. Woods Jan 2002

A Minimal Regular Ring Extension Of C(X), Melvin Henriksen, Robert M. Raphael, R. G. Woods

All HMC Faculty Publications and Research

Let G(X) denote the smallest (von Neumann) regular ring of real-valued functions with domain X that contains C(X), the ring of continuous real-valued functions on a Tikhonov topological space (X,Τ). We investigate when G(X) coincides with the ring C(X,Τδ) of continuous real-valued functions on the space (X,Τδ), where Τδ is the smallest Tikhonov topology on X for which tau subset of or equal to tau(delta) and C(X,Τδ) is von Neumann regular. The compact and metric spaces for which G(X) = C(X,Τδ) are characterized. Necessary, and different sufficient, conditions for the equality …


An Interactive Tutorial For Teaching Statistical Power, Christopher L. Aberson '99, Dale E. Berger, Michael R. Healy '04, Victoria L. Romero '07 Jan 2002

An Interactive Tutorial For Teaching Statistical Power, Christopher L. Aberson '99, Dale E. Berger, Michael R. Healy '04, Victoria L. Romero '07

CGU Faculty Publications and Research

This paper describes an interactive Web-based tutorial that supplements instruction on statistical power. This freely available tutorial provides several interactive exercises that guide students as they draw multiple samples from various populations and compare results for populations with differing parameters (for example, small standard deviation versus large standard deviation). The tutorial assignment includes diagnostic multiple-choice questions with feedback addressing misconceptions, and follow-up questions suitable for grading. The sampling exercises utilize an interactive Java applet that graphically demonstrates relationships between statistical power and effect size, null and alternative populations and sampling distributions, and Type I and II error rates. The applet …


Medtextus: An Ontology-Enhanced Medical Portal, Gondy Leroy, Hsinchun Chen Jan 2002

Medtextus: An Ontology-Enhanced Medical Portal, Gondy Leroy, Hsinchun Chen

CGU Faculty Publications and Research

In this paper we describe MedTextus, an online medical search portal with dynamic search and browse tools. To search for information, MedTextus lets users request synonyms and related terms specifically tailored to their query. A mapping algorithm dynamically builds the query context based on the UMLS ontology and then selects thesaurus terms that fit this context. Users can add these terms to their query and meta-search five medical databases. To facilitate browsing, the search results can be reviewed as a list of documents per database, as a set of folders into which all the documents are automatically categorized based on …


Evaluating Java Applets For Teaching On The Internet, Michael R. Healy '04, Dale E. Berger, Victoria L. Romero '07, Christopher L. Aberson '99, Amanda Saw '11 Jan 2002

Evaluating Java Applets For Teaching On The Internet, Michael R. Healy '04, Dale E. Berger, Victoria L. Romero '07, Christopher L. Aberson '99, Amanda Saw '11

CGU Faculty Publications and Research

The Web Interface for Statistics Education (http://wise.cgu.edu) is a website built around interactive tutorials designed to teach introductory and advanced statistical concepts. The tutorials use Java applets that dynamically illustrate the statistical concepts being taught. By using Java applets, we teach statistics in a manner not possible in a traditional classroom environment. In this paper, we provide examples of the applets, illustrate how students use them, and we report the outcome of a study that examined tutorial effectiveness as a learning tool.


Filling Preposition-Based Templates To Capture Information From Medical Abstracts, Gondy Leroy, Hsinchun Chen Jan 2002

Filling Preposition-Based Templates To Capture Information From Medical Abstracts, Gondy Leroy, Hsinchun Chen

CGU Faculty Publications and Research

Due to the recent explosion of information in the biomedical field, it is hard for a single researcher to review the complex network involving genes, proteins, and interactions. We are currently building GeneScene, a toolkit that will assist researchers in reviewing existing literature, and report on the first phase in our development effort: extracting the relevant information from medical abstracts. We are developing a medical parser that extracts information, fills basic prepositional-based templates, and combines the templates to capture the underlying sentence logic. We tested our parser on 50 unseen abstracts and found that it extracted 246 templates with a …


Intrinsic Knotting And Linking Of Complete Graphs, Erica Flapan Jan 2002

Intrinsic Knotting And Linking Of Complete Graphs, Erica Flapan

Pomona Faculty Publications and Research

We show that for every m∈N, there exists an n∈N such that every embedding of the complete graph Kn in R3 contains a link of two components whose linking number is at least m. Furthermore, there exists an r∈N such that every embedding of Kr in R3 contains a knot Q with |a2(Q)| ≥ m, where a2(Q) denotes the second coefficient of the Conway polynomial of Q.


Asymmetric Two-Colourings Of Graphs In S³, Erica Flapan, David Linnan Li Jan 2002

Asymmetric Two-Colourings Of Graphs In S³, Erica Flapan, David Linnan Li

Pomona Faculty Publications and Research

We prove that for any non-planar graph H, we can choose a two-colouring G of H such that G is intrinsically chiral, and if H is 3-connected and is not K3,3 or K5, then G is intrinsically asymmetric. No such asymmetric two-colouring is possible for K3,3 or K5.


Scroll Waves In The Presence Of Slowly Varying Anisotropy With Application To The Heart, S. Setayeshgar, Andrew J. Bernoff Dec 2001

Scroll Waves In The Presence Of Slowly Varying Anisotropy With Application To The Heart, S. Setayeshgar, Andrew J. Bernoff

All HMC Faculty Publications and Research

We consider the dynamics of scroll waves in the presence of rotating anisotropy, a model of the left ventricle of the heart in which the orientation of fibers in successive layers of tissue rotates. By choosing a coordinate system aligned with the fiber rotation and studying the phase dynamics of a straight but twisted scroll wave, we derive a Burgers’ equation with forcing associated with the fiber rotation rate. We present asymptotic solutions for scroll twist, verified by numerics, using a realistic fiber distribution profile. We make connection with earlier numerical and analytical work on scroll dynamics.


A Local Inversion Principle Of The Nash-Moser Type, Alfonso Castro, J. W. Neuberger Dec 2001

A Local Inversion Principle Of The Nash-Moser Type, Alfonso Castro, J. W. Neuberger

All HMC Faculty Publications and Research

We prove an inverse function theorem of the Nash-Moser type. The main difference between our method and that of [J. Moser, Proc. Nat. Acad. Sci. USA, 47 (1961), pp. 1824-1831] is that we use continuous steepest descent while Moser uses a combination of Newton-type iterations and approximate inverses. We bypass the loss of derivatives problem by working on finite dimensional subspaces of infinitely differentiable functions.


Meeting Medical Terminology Needs: The Ontology-Enhanced Medical Concept Mapper, Gondy Leroy, Hsinchun Chen Dec 2001

Meeting Medical Terminology Needs: The Ontology-Enhanced Medical Concept Mapper, Gondy Leroy, Hsinchun Chen

CGU Faculty Publications and Research

This paper describes the development and testing of the Medical Concept Mapper, a tool designed to facilitate access to online medical information sources by providing users with appropriate medical search terms for their personal queries. Our system is valuable for patients whose knowledge of medical vocabularies is inadequate to find the desired information, and for medical experts who search for information outside their field of expertise. The Medical Concept Mapper maps synonyms and semantically related concepts to a user's query. The system is unique because it integrates our natural language processing tool, i.e., the Arizona (AZ) Noun Phraser, with human-created …