Physical Sciences and Mathematics Commons^™

Epistemological Pluralism: Styles And Voices Within The Computer Culture, Sherry Turkle, Seymour Papert

Humanistic Mathematics Network Journal

No abstract provided.

What Is Mathematics And Why Don't They Know That?, Harald M. Ness

Humanistic Mathematics Network Journal

No abstract provided.

Mathematics From An English Major's Point Of View, Elizabeth Miller, Kathleen M. Shannon

Humanistic Mathematics Network Journal

No abstract provided.

Intervalley Scattering In Gaas And Inp Probed By Pulsed Far‐Infrared Transmission Spectroscopy, Peter N. Saeta, John F. Federici, Benjamin I. Greene, Douglas R. Dykaar

All HMC Faculty Publications and Research

The dynamics of photoexcited electrons in GaAs and InP were studied using the transmission of 200‐fs pulses of far‐infrared radiation in the spectral range 15–100 cm⁻¹. Kinetic traces of the infrared transmission as a function of delay between optical excitation and infrared probe show a probe‐limited decrease in transmission followed by a more gradual (0.7–2 ps) drop to a steady value, consistent with the slow return of electrons from high‐mass satellite valleys. Infrared transmission spectra, analyzed in the context of a Drude model, reveal density‐dependent electron mobilities 3–4 times below equilibrium n‐doped values. Electron‐hole collisions likely account …

A Theoretical Investigation Of The Ground And Low‐Lying Excited States Of Butadiene Radical Cation, Robert J. Cave, Michael G. Perrott '90

All HMC Faculty Publications and Research

Results are presented from ab initio calculations on the ground and several low‐lying excited states of the butadiene radical cation. In particular, we have calculated geometries for the ground and several excited states at the multiconfiguration self‐consistent field level and characterized the planar stationary points. The vertical ionization potentials from the neutral molecule ground state and vertical excitation energies at the computed equilibrium geometry of the cation were also examined. A variety of methods were tested for the calculation of ionization potentials and excitation energies, including multiconfiguration self‐consistent field, multireference singles and doubles configuration interaction (with and without size‐consistency correction), …

Nitrogen And Carbon Isotope Studies Of A Bat Guano Core From Eagle Creek Cave, Arizona, Usa, Hiroshi Mizutani, Donald A. Mcfarlane, Yuko Kabaya

WM Keck Science Faculty Papers

Nitrogen and carbon isotope ratios were studied in a stratified deposit of guano of Mexican Free-tailed bats in Eagle Creek Cave, Arizona, U.S.A. Little diagenetic change was observed over the 25-year time span of the guano deposit. High aridity and reduced circulation of air in the cave are hypothesized to have slowed the normally rapid decomposition of the excreta and the subsequent escape of resultant ammonia. The results suggest the high dependency of the speed of diagenetic change on specific physical and other conditions of the caves and indicate that great care need be exercised in the interpretation of the …

Carbon And Nitrogen Isotopic Signatures Of Bat Guanos As A Record Of Past Environments, Hiroshi Mizutani, Donald A. Mcfarlane, Yuko Kabaya

WM Keck Science Faculty Papers

Carbon and nitrogen isotope ratios were measured for various ecogeochemical samples relevant to bat guano ecosystems. In particular, ca. 800-year-old subfossil guano from Jackson's Bay Cave Compex, Jamaica, yielded ratios similar to the modern guano from other Jamaican bat caves but quite different from modern guano of the same area. Diagenetic change and differences in bat food habits were unlikely explanations for the observation. Instead, insects that feed on C4 and CAM plants were the main prey for the bats in present Jackson's Bay area, while the ultimate source of organic matter for bats in other Jamaican caves and for …

Optical Rectification At Semiconductor Surfaces, Shun Lien Chuang, Stefan Schmitt-Rink, Benjamin I. Greene, Peter N. Saeta, Anthony F. J. Levi

All HMC Faculty Publications and Research

We show that far-infrared radiation can be generated in the depletion field near semiconductor surfaces via the inverse Franz-Keldysh effect or electric-field-induced optical rectification. This mechanism is conceptually different from those previously proposed and accounts for many recent experimental observations.

Intrinsic Chirality Of Complete Graphs, Erica Flapan, Nikolai Weaver

Pomona Faculty Publications and Research

A graph is said to be intrinsically chiral if no embedding of the graph in 3-space is respected by any ambient orientation-reversing homeomorphism. In this note, we characterize those complete graphs that are intrinsically chiral.

A Casscf Study Of Various Rotamers Of The Hexatriene Radical Cation, Robert J. Cave, Jenifer L. Johnson

All HMC Faculty Publications and Research

Results are presented from ab initio calculations on the ground and two low-lying excited states of the hexatriene radical cation in a variety of stable conformations of the electronic ground state of the molecule. We have performed Hartree-Fock geometry optimizations using the STO-3G and 6-31g basis sets and have performed vibrational analyses for all stable conformers in the 6-31G basis. In addition, we have performed geometry optimizations in both basis sets using CASSCF wave functions where the five π electrons are correlated. No new geometrical information is obtained at this level of treatment. Excitation energies to the two lowest-lying doublet …

Ultrafast Electronic Disordering During Femtosecond Laser Melting Of Gaas, Peter N. Saeta, J.-K. Wang, Y. Siegal, N. Bloembergen, E. Mazur

All HMC Faculty Publications and Research

We have observed an ultrarapid electronic phase transformation to a centrosymmetric electronic state during laser excitation of GaAs with intense femtosecond pulses. Reflection second-harmonic intensity from the upper 90 atomic layers vanishes within 100 fs; reflectivity rises within 0.5 ps to a steady value characteristic of a metallic molten phase, long before phonon emission can heat the lattice to the melting temperature.

The Calculus Virgin, Louis Leithold

Humanistic Mathematics Network Journal

No abstract provided.

Leibniz — Beyond The Calculus, Hardy Grant

Humanistic Mathematics Network Journal

No abstract provided.

Student Seminars On "Famous Equations", Richard G. Montgomery

Humanistic Mathematics Network Journal

No abstract provided.

The Human/Computer Interface: Their Side Or Ours?, R. S.D. Thomas

Humanistic Mathematics Network Journal

No abstract provided.

An Historical Approach To Precalculus And Calculus, Victor J. Katz

Humanistic Mathematics Network Journal

No abstract provided.

Ethics In Mathematics: A Request For Information, Robert P. Webber

Humanistic Mathematics Network Journal

No abstract provided.

An Alternative Approach To The History Of Mathematics, Claudia Henrion

Humanistic Mathematics Network Journal

No abstract provided.

Mathematics And Philosophy: The Story Of A Misunderstanding, Gian-Carlo Rota

Humanistic Mathematics Network Journal

No abstract provided.

The Hermeneutics Of Mathematical Modeling, David Tudor

Humanistic Mathematics Network Journal

No abstract provided.

Ultimately, Mathematics Is Poetry, Alfred Warrinnier

Humanistic Mathematics Network Journal

No abstract provided.

Mathematics, Truth And Integrity, Peter Hilton, Jean Pedersen

Humanistic Mathematics Network Journal

No abstract provided.

Mathematics: Contributions By Women, Jacqueline M. Dewar

Humanistic Mathematics Network Journal

No abstract provided.

Augsburg's Humanistic Curriculum Project, Larry Copes, Beverly Stratton

Humanistic Mathematics Network Journal

No abstract provided.

How Mathematics Teachers Use "Writing To Learn", Susan Hunter

Humanistic Mathematics Network Journal

No abstract provided.

Mathematics And Poetry : Isolated Or Integrated?, Joanne S. Growney

Humanistic Mathematics Network Journal

No abstract provided.

On Teaching In The Mathematical Sciences, James M. Cargal

Humanistic Mathematics Network Journal

No abstract provided.

Mathematics For Life And Society, Miriam Lipschutz-Yevick

Humanistic Mathematics Network Journal

No abstract provided.

On A Lower Bound For The Redundancy Of Reliable Networks With Noisy Gates, Nicholas Pippenger

All HMC Faculty Publications and Research

A proof is provided that a logarithmic redundancy factor is necessary for the reliable computation of the parity function by means of a network with noisy gates. This result was first stated by R.L. Dobrushin and S.I. Ortyukov (1977). However, the authors believe that the analysis given by Dobrushin and Ortyukov is not entirely correct. The authors establish the result by following the same steps and by replacing the questionable part of their analysis with entirely new arguments.

Disjoint Covers In Replicated Heterogeneous Arrays, P.K. Mckinley, N. Hasan, Ran Libeskind-Hadas, C.L. Liu

All HMC Faculty Publications and Research

Reconfigurable chips are fabricated with redundant elements that can be used to replace the faulty elements. The fault cover problem consists of finding an assignment of redundant elements to the faulty elements such that all of the faults are repaired. In reconfigurable chips that consist of arrays of elements, redundant elements are configured as spare rows and spare columns.

This paper considers the problem in which a chip contains several replicates of a heterogeneous array, one or more sets of spare rows, and one or more sets of spare columns. Each set of spare rows is identical to the set …