Digital Commons Network^™

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 …

Rental Harmony: Sperner's Lemma In Fair Division, Francis E. Su

All HMC Faculty Publications and Research

No abstract provided in this article.

Review: Daniel Belgrad, The Culture Of Spontaneity: Improvisation And The Arts In Postwar America (Chicago, 1998), Wendy Martin

CGU Faculty Publications and Research

Book review.

Recounting Fibonacci And Lucas Identities, Arthur T. Benjamin, Jennifer J. Quinn

All HMC Faculty Publications and Research

No abstract provided in this article.

Mla Interviews From The Candidiates Point Of View, Lee Joan Skinner

CMC Faculty Publications and Research

This article is based on Lee Skinner's presentation at the 1998 MLA convention in San Francisco, California.

Stability Of Self-Similar Solutions For Van Der Waals Driven Thin Film Rupture, Thomas P. Witelski, Andrew J. Bernoff

All HMC Faculty Publications and Research

Recent studies of pinch-off of filaments and rupture in thin films have found infinite sets of first-type similarity solutions. Of these, the dynamically stable similarity solutions produce observable rupture behavior as localized, finite-time singularities in the models of the flow. In this letter we describe a systematic technique for calculating such solutions and determining their linear stability. For the problem of axisymmetric van der Waals driven rupture (recently studied by Zhang and Lister), we identify the unique stable similarity solution for point rupture of a thin film and an alternative mode of singularity formation corresponding to annular “ring rupture.”

Almost Periodic Factorization Of Certain Block Triangular Matrix Functions, Ilya M. Spitkovsky, Darryl H. Yong

All HMC Faculty Publications and Research

Let

where , and . For rational such matrices are periodic, and their Wiener-Hopf factorization with respect to the real line always exists and can be constructed explicitly. For irrational , a certain modification (called an almost periodic factorization) can be considered instead. The case of invertible and commuting , was disposed of earlier-it was discovered that an almost periodic factorization of such matrices does not always exist, and a necessary and sufficient condition for its existence was found. This paper is devoted mostly to the situation when is not invertible but the commute pairwise (). The complete description is …

Black Holes And Five-Brane Thermodynamics, Emil Martinec, Vatche Sahakian

All HMC Faculty Publications and Research

The phase diagram for Dp-branes in M theory compactified on T⁴,T⁴/Z₂,T⁵, and T⁶ is constructed. As for the lower-dimensional tori considered in our previous work [E. Martinec and V. Sahakian, Phys. Rev. D 59, 124005 (1999)], the black brane phase at high entropy connects onto matrix theory at low entropy; we thus recover all known instances of matrix theory as consequences of the Maldacena conjecture. The difficulties that arise for T⁶ are reviewed. We also analyze the D1-D5 system on T⁵; we discuss its relation to matrix models …

Different Proctolin Neurons Elicit Distinct Motor Patterns From A Multifunctional Neuronal Network, Dawn M. Blitz, Andrew E. Christie, Melissa J. Coleman, Brian J. Norris, Eve Marder, Michael P. Nusbaum

WM Keck Science Faculty Papers

Distinct motor patterns are selected from a multifunctional neuronal network by activation of different modulatory projection neurons. Subsets of these projection neurons can contain the same neuromodulator(s), yet little is known about the relative influence of such neurons on network activity. We have addressed this issue in the stomatogastric nervous system of the crab Cancer borealis. Within this system, there is a neuronal network in the stomatogastric ganglion (STG) that produces many versions of the pyloric and gastric mill rhythms. These different rhythms result from activation of different projection neurons that innervate the STG from neighboring ganglia and modulate STG …

Why The Player Never Wins In The Long Run At La Blackjack, Arthur T. Benjamin, Michael Lauzon '00, Christopher Moore '00

All HMC Faculty Publications and Research

No abstract provided in this article.

Probing Nonequilibrium Electron Distributions In Gold By Use Of Second Harmonic Generation, K. L. Moore '99, Thomas D. Donnelly

All HMC Faculty Publications and Research

Second-harmonic radiation is generated at a gold surface by use of a laser pulse that is varied in duration from 14 to 29 fs and in intensity from 10⁹ to 10¹¹W/cm² . At laser intensities below 10¹⁰W/cm² , the second-harmonic signal has the expected quadratic dependence on pump-laser intensity; however, at higher intensities, the dependence is supraquadratic. This difference arises because the leading edge of the laser pulse interacts significantly with the gold electrons to create a nonequilibrium, photoexcited distribution. The second-harmonic generation process occurs before electron–electron or electron–phonon collisions can equilibrate the …

Some Intranational Evidence On Output-Inflation Trade-Offs, Gregory Hess, Kwanho Shin

CMC Faculty Publications and Research

In a seminal paper, Robert E. Lucas, Jr. provided the theoretical relationship between aggregate demand and real output based on relative price confusion at the individual market level. Subsequently, an alternative New Keynesian aggregate supply relationship was derived and it was demonstrated that the two theories can be distinguished on the basis of how both the rate of inflation and the volatility of relative prices affect its slope. By emphasizing the first implication of New Keynesian theory, strong evidence was obtained supporting this model using international data. We also concentrate on the second difference between the two theories. We derive …

Black Holes And The Sym Diagram. Ii, Emil Martinec, Vatche Sahakian

All HMC Faculty Publications and Research

The complete phase diagram of objects in M theory compactified on tori T^p,p=1,2,3, is elaborated. Phase transitions occur when the object localizes on cycle(s) (the Gregory-Laflamme transition), or when the area of the localized part of the horizon becomes one in string units (the Horowitz-Polchinski correspondence point). The low-energy, near-horizon geometry that governs a given phase can match onto a variety of asymptotic regimes. The analysis makes it clear that the matrix conjecture is a special case of the Maldacena conjecture.

Carnality In ‘El Matadero', Lee Joan Skinner

CMC Faculty Publications and Research

Esteban Echeverria's short story "El matadero" is generally acknowledged as a literary masterpiece in miniature. It is widely anthologized and has been called the inaugural work of Argentine short fiction, if not the first Latin American short story. Seymour Menton positions it as the first story in his influential anthology El cuento hispanoamericano and calls it "una verdadera obra de arte" (34); David William Foster refers to it as "the founding text of Argentine fiction" (Sexual Textualities 135). Although the story has been popularly and critically acclaimed, it also presents certain problems for its readers. Written by an avowed Romantic, …

Unevening The Odds Of "Even Up", Arthur T. Benjamin, Jennifer J. Quinn

All HMC Faculty Publications and Research

No abstract provided in this article.

The Best Way To Knock 'M Down, Arthur T. Benjamin, Matthew T. Fluet '99

All HMC Faculty Publications and Research

"Knock 'm Down" is a game of dice that is so easy to learn that it is being played in classrooms around the world. Although this game has been effective at developing students' intuition about probability [Fendel et al. 1997; Hunt 1998], we will show that lurking underneath this deceptively simple game are many surprising and highly unintuitive results.

Family Names, Gayle Greene

Scripps Faculty Publications and Research

I was ten when my mother changed our name from Greenberg to Greene. I had no idea why she did this, nor, presumably, did she. It had to do with the breakup of her marriage, that was clear-she no longer wanted his name. But why, I asked later, when I was old enough to wonder about such things, didn't she go back to her maiden name?

Field Station Under Threat, Paul Faulstich

Pitzer Faculty Publications and Research

As reported in the last issue of The Other Side, The Bernard Biological Field Station of the Colleges is slated to be the site of the Keck Graduate Institute, the newest (but yet unbuilt) addition to the Claremont Consortium. With Pitzer casting the sole dissenting vote, the Claremont Colleges approved construction of the Keck Institute on eleven acres of the 85 acre Field Station.

Land Development And Biotechnology At The Claremont Colleges, Paul Faulstich

Pitzer Faculty Publications and Research

Founded on the Oxford model of a cluster of institutions, the Claremont Colleges has periodically established a new school. In the Spring of 1997, the Board of Fellows of the Claremont University Center charged with policy-making for the consortium-voted to establish a seventh college; the Keck Graduate Institute of applied life sciences. or bioengineering. Despite other landholdings, including a golf course and a non-operational gravel quarry, the Board of Fellows voted to site the New Venture on a portion-approximately eleven acres--of the Bernard Biological Field Station. (Pitzer's vote was cast against building on the Field Station.)

Magic "Squares" Indeed, Arthur T. Benjamin, Kan Yasuda '97

All HMC Faculty Publications and Research

No abstract provided in this article.

Images Of/And The Postmodern. Review Of Spectacular Allegories: Postmodern American Writing And The Politics Of Seeing By Josh Cohen, Kathleen Fitzpatrick

Pomona Faculty Publications and Research

Josh Cohen, in his new book Spectacular Allegories: Postmodern American Writing and the Politics of Seeing, argues that postmodern American novelists ranging from Norman Mailer to Joan Didion, Robert Coover to James Ellroy, do not merely fall into accord with this critique -text good; image bad- but are in fact using the allegorical nature of their encounters with and representations of visual culture as a means of reintroducing the image to history, an attempt to construct a new critical politics of visuality. The possibility of a critical visual agency is raised for Cohen in these writers’ gendered representations of the …

Motivation And Culture, Claudia Strauss

Pitzer Faculty Publications and Research

Since the 1970s the cognitive sciences have offered multidisciplinary ways of understanding the mind and cognition. The MIT Encyclopedia of the Cognitive Sciences (MITECS) is a landmark, comprehensive reference work that represents the methodological and theoretical diversity of this changing field.

This particular work is one of 471 concise entries, from Acquisition and Adaptationism to Wundt and X-bar Theory. Each article, written by a leading researcher in the field, provides an accessible introduction to an important concept in the cognitive sciences, as well as references or further readings. Six extended essays, which collectively serve as a roadmap to the articles, …

Grazing Arizona: Public Land Management In The Southwest, Char Miller

Pomona Faculty Publications and Research

In February of 1999, the chief of the U.S. Forest Service, Michael Dombeck, placed a moratorium on road building on most roadless areas. In October, President Clinton put forth an initiative to prohibit road building on 40 million acres of roadless area. Such modifications in Forest Service land management decisions is not new as suggested by Char Miller in this look back at early grazing decisions by Pinchot. To be proactive and reactive at the same time in relation to changing social pressures and political realties may be the legacy of the agency.

A Note On Sexual Dimorphism In Nesophontes Edithae (Mammalia: Insectivora), An Extinct Island-Shrew From Puerto Rico, Donald A. Mcfarlane

WM Keck Science Faculty Papers

The island-shrew, Nesophontes edithae Anthony 1916, Mean is the only Puerto Rican representative of the monogeneric family Nesophontidae.

Bounds On A Bug, Arthur T. Benjamin, Matthew T. Fluet '99

All HMC Faculty Publications and Research

In the game of Cootie, players race to construct a "cootie bug" by rolling a die to collect component parts. Each cootie bug is composed of a body, a head, two eyes, one nose, two antennae, and six legs. Players must first acquire the body of the bug by rolling a 1. Next, they must roll a 2 to add the head to the body. Once the body and head are both in place, the remaining body parts can be obtained in any order by rolling two 3s for the eyes, one 4 for the nose, two 5s for the …

On The Number Of Radially Symmetric Solutions To Dirichlet Problems With Jumping Nonlinearities Of Superlinear Order, Alfonso Castro, Hendrik J. Kuiper

All HMC Faculty Publications and Research

This paper is concerned with the multiplicity of radially symmetric solutions u(x) to the Dirichlet problem

Δu+f(u)=h(x)+cφ(x)

on the unit ball Ω⊂R^N with boundary condition u=0 on ∂Ω. Here φ(x) is a positive function and f(u) is a function that is superlinear (but of subcritical growth) for large positive u, while for large negative u we have that f'(u)<μ, where μ is the smallest positive eigenvalue for Δψ+μψ=0 in Ω with ψ=0 on ∂Ω. It is shown that, given any integer k≥0, the value c may be chosen so large that there are 2k+1 solutions with k or less interior nodes. Existence of positive solutions is excluded for large enough values of c.

Model Updating By Adding Known Masses And Stiffnesses, Philip D. Cha, Lisette G. De Pillis

All HMC Faculty Publications and Research

New approaches are developed to update the analytical mass and stiffness matrices of a system. By adding known masses to the structure of interest, measuring the modes of vibration of this mass-modified system, and finally using this set of new data in conjunction with the initial modal survey, the mass matrix of the structure can be corrected. A similar approach can also be used to update the stiffness matrix of the system by attaching known stiffnesses. Manipulating the mass and stiffness correction matrices into vector forms, the connectivity information can be enforced, thereby preserving the physical configuration of the system, …

An Inverse Function Theorem, Alfonso Castro, J. W. Neuberger

All HMC Faculty Publications and Research

In this note we present a local surjectivity result which is applicable to differential equations for which full boundary conditions may not be known. Our method uses continuous steepest descent and Sobolev gradients.

Black Holes And The Sym Phase Diagram, Miao Li, Emil Martinec, Vatche Sahakian

All HMC Faculty Publications and Research

Making combined use of the matrix and Maldacena conjectures, the relation between various thermodynamic transitions in super Yang-Mills (SYM) theory and supergravity is clarified. The thermodynamic phase diagram of an object in DLCQ M theory in four and five non-compact space dimensions is constructed; matrix strings, matrix black holes, and black p-branes are among the various phases. Critical manifolds are characterized by the principles of correspondence and longitudinal localization, and a triple point is identified. The microscopic dynamics of the matrix string near two of the transitions is studied; we identify a signature of black hole formation from SYM physics.

A Theoretical Study Of The Electronic Coupling Element For Electron Transfer In Water, Newt E. Miller '99, Matthew C. Wander '97, Robert J. Cave

All HMC Faculty Publications and Research

The electronic coupling element for electron transfer between a donor and acceptor in water is examined using simulations combining molecular dynamics and semiempirical quantum mechanics. In the first phase of the simulations a model donor and acceptor are solvated in water, using realistic potentials. Following equilbration, molecular dynamics simulations are performed with the donor, acceptor, and water at approximately 300 K, under periodic boundary conditions. In the second phase of the simulation, the electronic coupling element between the donor and acceptor is calculated for a number of time slices, in the presence of the intervening water molecules (those having a …