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Claremont Colleges

2006

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Modified Control Software For Imaging Ultracold Atomic Clouds, Dwight L. Whitaker, A. Sharma, J. M. Brown Dec 2006

Modified Control Software For Imaging Ultracold Atomic Clouds, Dwight L. Whitaker, A. Sharma, J. M. Brown

Pomona Faculty Publications and Research

A charge-coupled device (CCD) camera capable of taking high-quality images of ultracold atomic samples can often represent a significant portion of the equipment costs in atom trapping experiment. We have modified the commercial control software of a CCD camera designed for astronomical imaging to take absorption images of ultracold rubidium clouds. This camera is sensitive at 780 nm and has been modified to take three successive 16-bit images at full resolution. The control software can be integrated into a Matlab graphical user interface with fitting routines written as Matlab functions. This camera is capable of recording high-quality images at a …

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Teaching Time Savers: Some Advice On Giving Advice, Michael E. Orrison Jr. Dec 2006

Teaching Time Savers: Some Advice On Giving Advice, Michael E. Orrison Jr.

All HMC Faculty Publications and Research

There are always a lot of questions that need to be answered at the beginning of a course. When are office hours? What are the grading policies? How many exams will there be? Will late homework be accepted? We have all seen the answers to these sorts of questions form the bulk of a standard course syllabus, and most of us feel an obligation (and rightly so) to provide such information.

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The Qingdao Twin Registry: A Focus On Chronic Disease Research, C. Anderson Johnson, Zengchang Pang, Feng Ning, Jennifer B. Unger, Shaojie Wang, Qian Guo, Weihua Cao, Liming Lee Dec 2006

The Qingdao Twin Registry: A Focus On Chronic Disease Research, C. Anderson Johnson, Zengchang Pang, Feng Ning, Jennifer B. Unger, Shaojie Wang, Qian Guo, Weihua Cao, Liming Lee

CGU Faculty Publications and Research

With the changing patterns of morbidity and mortality in China, noncommunicable chronic diseases have become the major threats to the health of the Chinese population. The causes of chronic diseases include genetic factors and behavioral risk factors such as the use of tobacco, alcohol, and other drugs, unhealthy dietary behaviors, and lack of physical activity. Twin studies offer a unique opportunity to disentangle the genetic and environmental risk and protective factors for chronic disease. The Qingdao Twin Registry (QTR) was initiated in 1998 as part of the National Chinese Twin Registry. Over 11,000 pairs of twins and multiples of all …

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Testing Tenure: Let The Market Decide, Michael Shermer Dec 2006

Testing Tenure: Let The Market Decide, Michael Shermer

CGU Faculty Publications and Research

Tenure debates and disputes are often irresolvable because of the complex and multivariate nature of contractual relationships between faculty and administration, and the nuanced and varying beliefs about tenure held by the professoriate. The Ceci et al. study leads this commentator to suggest a simple solution - allow individual institutions to define the parameters of tenure according to their unique core values.

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Strings, Chains, And Ropes, Darryl H. Yong Nov 2006

Strings, Chains, And Ropes, Darryl H. Yong

All HMC Faculty Publications and Research

Following Antman [Amer. Math. Mon., 87 (1980), pp. 359–370], we advocate a more physically realistic and systematic derivation of the wave equation suitable for a typical undergraduate course in partial differential equations. To demonstrate the utility of this derivation, three applications that follow naturally are described: strings, hanging chains, and jump ropes.

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Emergence Of The Fuzzy Horizon Through Gravitational Collapse, Anand Murugan '07, Vatche Sahakian Nov 2006

Emergence Of The Fuzzy Horizon Through Gravitational Collapse, Anand Murugan '07, Vatche Sahakian

All HMC Faculty Publications and Research

For a large enough Schwarzschild black hole, the horizon is a region of space where gravitational forces are weak; yet it is also a region leading to numerous puzzles connected to stringy physics. In this work, we analyze the process of gravitational collapse and black hole formation in the context of light-cone M-theory. We find that, as a shell of matter contracts and is about to reveal a black hole horizon, it undergoes a thermodynamic phase transition. This involves the binding of D0 branes into D2’s, and the new phase leads to large membranes of the size of the horizon. …

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Summing Cubes By Counting Rectangles, Arthur T. Benjamin, Jennifer J. Quinn, Calyssa Wurtz Nov 2006

Summing Cubes By Counting Rectangles, Arthur T. Benjamin, Jennifer J. Quinn, Calyssa Wurtz

All HMC Faculty Publications and Research

No abstract provided in this article.

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Self-Avoiding Walks And Fibonacci Numbers, Arthur T. Benjamin Nov 2006

Self-Avoiding Walks And Fibonacci Numbers, Arthur T. Benjamin

All HMC Faculty Publications and Research

By combinatorial arguments, we prove that the number of self-avoiding walks on the strip {0, 1} × Z is 8Fn − 4 when n is odd and is 8Fn − n when n is even. Also, when backwards moves are prohibited, we derive simple expressions for the number of length n self-avoiding walks on {0, 1} × Z, Z × Z, the triangular lattice, and the cubic lattice.

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How Effective Is Security Screening Of Airline Passengers?, Susan E. Martonosi, Arnold Barnett Nov 2006

How Effective Is Security Screening Of Airline Passengers?, Susan E. Martonosi, Arnold Barnett

All HMC Faculty Publications and Research

With a simple mathematical model, we explored the antiterrorist effectiveness of airport passenger prescreening systems. Supporters of these systems often emphasize the need to identify the most suspicious passengers, but they ignore the point that such identification does little good unless dangerous items can actually be detected. Critics often focus on terrorists' ability to probe the system and thereby thwart it, but ignore the possibility that the very act of probing can deter attempts at sabotage that would have succeeded. Using the model to make some preliminary assessments about security policy, we find that an improved baseline level of screening …

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How Much Does Violence Tax Trade?, S. Brock Blomberg, Gregory Hess Nov 2006

How Much Does Violence Tax Trade?, S. Brock Blomberg, Gregory Hess

CMC Faculty Publications and Research

We investigate the empirical effect of violence, as compared to other trade impediments, on trade flows. Our analysis is based on a panel data set with annual observations on 177 countries from 1968 to 1999, which brings together information from the Rose data set, the iterate data set for terrorist events, and data sets of external and internal conflict. We explore these data with traditional and theoretical gravity models. We calculate that, for a given country year, the presence of terrorism together with internal and external conflict is equivalent to as much as a 30% tariff on trade. This is …

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Certifications Offered By Cost Estimating Organizations, Donald S. Remer, Karen M. Ahle, Kevin J. Alley, John Silny, Karen Hsin Oct 2006

Certifications Offered By Cost Estimating Organizations, Donald S. Remer, Karen M. Ahle, Kevin J. Alley, John Silny, Karen Hsin

All HMC Faculty Publications and Research

There has been an increasing trend in professional and engineering circles to place greater emphasis on official credentials. These credentials commonly come in the form of certificates – documented recognition by a professional body that an engineer or other professional has the qualifications and technical knowledge to be a practitioner in that field. These certificates are somewhat analogous to merit badges in scouting – the certification is evidence that the holder has a certain minimum level of competence in the subject area. This review will help you decide what certifications are applicable to you and the requirements to obtain a …

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In Situ Muscle Power Differs Without Varying In Vitro Mechanical Properties In Two Insect Leg Muscles Innervated By The Same Motor Neuron, Anna N. Ahn, Kenneth Meijer, Robert J. Full Sep 2006

In Situ Muscle Power Differs Without Varying In Vitro Mechanical Properties In Two Insect Leg Muscles Innervated By The Same Motor Neuron, Anna N. Ahn, Kenneth Meijer, Robert J. Full

All HMC Faculty Publications and Research

The mechanical behavior of muscle during locomotion is often predicted by its anatomy, kinematics, activation pattern and contractile properties. The neuromuscular design of the cockroach leg provides a model system to examine these assumptions, because a single motor neuron innervates two extensor muscles operating at a single joint. Comparisons of the in situ measurements under in vivo running conditions of muscle 178 to a previously examined muscle (179) demonstrate that the same inputs (e.g. neural signal and kinematics) can result in different mechanical outputs. The same neural signal and kinematics, as determined during running, can result in different mechanical functions, …

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Teaching Time Savers: Style Points, Michael E. Orrison Jr. Aug 2006

Teaching Time Savers: Style Points, Michael E. Orrison Jr.

All HMC Faculty Publications and Research

When I began as an assistant professor, I had a pretty good sense of how much time it would take for me to prepare for each class. After a few conversations with my new colleagues, I even had a good sense of how much time I should devote to tasks like office hours and committee work. Somewhere in the middle of grading my first exam, though, it became painfully clear that I had underestimated the amount of time I would need to grade exams!

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Introducing Mediacommons, Kathleen Fitzpatrick Jul 2006

Introducing Mediacommons, Kathleen Fitzpatrick

Pomona Faculty Publications and Research

At the moment, we imagine MediaCommons as a wide-ranging network with a relatively static point of entry that brings the participant into the MediaCommons community and makes apparent the wealth of different resources at his or her disposal. On this front page will be different modules highlighting what's happening in various nodes ("today in the blogs"; active forum topics; "just posted" texts from journals; featured projects). One module on this front page might be made customizable ("My MediaCommons"), such that participants can in some fashion design their own interfaces with the network, tracking the conversations and texts in which they …

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Mean Field Effects For Counterpropagating Traveling Wave Solutions Of Reaction-Diffusion Systems, Andrew J. Bernoff, R. Kuske, B. J. Matkowsky, V. Volpert Jul 2006

Mean Field Effects For Counterpropagating Traveling Wave Solutions Of Reaction-Diffusion Systems, Andrew J. Bernoff, R. Kuske, B. J. Matkowsky, V. Volpert

All HMC Faculty Publications and Research

In many problems, e.g., in combustion or solidification, one observes traveling waves that propagate with constant velocity and shape in the x direction, say, are independent of y and z and describe transitions between two equilibrium states, e.g., the burned and the unburned reactants. As parameters of the system are varied, these traveling waves can become unstable and give rise to waves having additional structure, such as traveling waves in the y and z directions, which can themselves be subject to instabilities as parameters are further varied. To investigate this scenario we consider a system of reaction-diffusion equations with a …

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Perception Precedes Computation: Can Familiarity Preferences Explain Apparent Calculation By Human Babies?, David S. Moore, Laura A. Cocas Jul 2006

Perception Precedes Computation: Can Familiarity Preferences Explain Apparent Calculation By Human Babies?, David S. Moore, Laura A. Cocas

Pitzer Faculty Publications and Research

Two studies of 5-month-old infants explored whether a phenomenon reported by K. Wynn (1992) reflects a familiarity preference instead of a mathematical competence. Experiment 1 was a conceptual replication of Wynn's study. When data were analyzed with the relatively liberal statistical approach used by Wynn, the original phenomenon was replicated. However, an analysis of variance revealed that girls and boys behaved in different ways, and that boys did not behave as Wynn would have predicted. Experiment 2 was identical to Experiment 1, with one exception that should not have influenced computation: Infants in this study were completely familiarized with the …

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Quadratic Forms And Height Functions, Lenny Fukshansky Jun 2006

Quadratic Forms And Height Functions, Lenny Fukshansky

CMC Faculty Publications and Research

The effective study of quadratic forms originated with a paper of Cassels in 1955, in which he proved that if an integral quadratic form is isotropic, then it has non-trivial zeros of bounded height. Here height stands for a certain measure of arithmetic complexity, which we will make precise. This theorem has since been generalized and extended in a number of different ways. We will discuss some of such generalizations for quadratic spaces over a fixed number field as well as over the field of algebraic numbers. Specifically, let K be either a number field or its algebraic closure, and …

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On The Future Of Peer Review In Electronic Scholarly Publishing, Kathleen Fitzpatrick Jun 2006

On The Future Of Peer Review In Electronic Scholarly Publishing, Kathleen Fitzpatrick

Pomona Faculty Publications and Research

Over the last several months, as I've met with the folks from if:book and with the quite impressive group of academics we pulled together to discuss the possibility of starting an all-electronic scholarly press, I've spent an awful lot of time thinking and talking about peer review-how it currently functions, why we need it, and how it might be improved. Peer review is extremely important-I want to acknowledge that right up front-but it threatens to become the axle around which all conversations about the future of publishing get wrapped, like Isadora Duncan's scarf, strangling any possible innovations in scholarly communication …

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Hole Dynamics In Polymer Langmuir Films, James C. Alexander, Andrew J. Bernoff, Elizabeth K. Mann, J. Adin Mann Jr., Lu Zou Jun 2006

Hole Dynamics In Polymer Langmuir Films, James C. Alexander, Andrew J. Bernoff, Elizabeth K. Mann, J. Adin Mann Jr., Lu Zou

All HMC Faculty Publications and Research

This article develops a model for the closing of a gaseous hole in a liquid domain within a two-dimensional fluid layer coupled to a Stokesian subfluid substrate, and compares this model to experiments following hole dynamics in a polymer Langmuir monolayer. Closure of such a hole in a fluid layer is driven by the line tension at the hole boundary and the difference in surface pressure within the hole and far outside it. The observed rate of hole closing is close to that predicted by our model using estimates of the line tension obtained by other means, assuming that the …

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Role Of Beat Noise In Limiting The Sensitivity Of Optical Coherence Tomography, Richard C. Haskell, David Liao, Adam E. Pivonka, Tera L. Bell, Brendan R. Haberle, Barbara M. Hoeling, Daniel C. Petersen Jun 2006

Role Of Beat Noise In Limiting The Sensitivity Of Optical Coherence Tomography, Richard C. Haskell, David Liao, Adam E. Pivonka, Tera L. Bell, Brendan R. Haberle, Barbara M. Hoeling, Daniel C. Petersen

All HMC Faculty Publications and Research

The sensitivity and dynamic range of optical coherence tomography (OCT) are calculated for instruments utilizing two common interferometer configurations and detection schemes. Previous researchers recognized that the performance of dual-balanced OCT instruments is severely limited by beat noise, which is generated by incoherent light backscattered from the sample. However, beat noise has been ignored in previous calculations of Michelson OCT performance. Our measurements of instrument noise confirm the presence of beat noise even in a simple Michelson interferometer configuration with a single photodetector. Including this noise, we calculate the dynamic range as a function of OCT light source power, and …

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Review: Hubert Steinke, Irritating Experiments: Haller’S Concept And The European Controversy On Irritability And Sensibility, 1750-90 (Amsterdam And New York, 2005), Andre Wakefield Jun 2006

Review: Hubert Steinke, Irritating Experiments: Haller’S Concept And The European Controversy On Irritability And Sensibility, 1750-90 (Amsterdam And New York, 2005), Andre Wakefield

Pitzer Faculty Publications and Research

Reviewed work: Hubert Steinke. Irritating Experiments: Haller's Concept and the European Controversy on Irritability and Sensibility, 1750-90. Amsterdam and New York: Rodopi, 2005. 354 pp. $97.00 (cloth), ISBN 978-90-420-1852-5.

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Niche To Mainstream In Sustainable Urban Food Systems: The Case Of Food Distribution In Portland, Oregon, Bowen Close May 2006

Niche To Mainstream In Sustainable Urban Food Systems: The Case Of Food Distribution In Portland, Oregon, Bowen Close

Pomona Senior Theses

To address the negative environmental, political, and social consequences of the dominant, industrialized global food system, communities around the world have developed goals and values underlying a sustainable food system. Conceptualizing food production, distribution, and consumption as systems helps clarify the ways food affects social and natural environments, with the distribution element as the critical juncture where the product reaches the consumer. Urban food systems are a particularly important environment in which to study movements toward sustainability. This paper focuses on the movement for a sustainable food system in Portland, Oregon, with particular focus on the city’s markets for …

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A Fast Fourier Transform For The Symmetric Group, Tristan Brand May 2006

A Fast Fourier Transform For The Symmetric Group, Tristan Brand

HMC Senior Theses

A discrete Fourier transform, or DFT, is an isomorphism from a group algebra to a direct sum of matrix algebras. An algorithm that efficiently applies a DFT is called a fast Fourier transform, or FFT. The concept of a DFT will be introduced and examined from both a general and algebraic perspective. We will then present and analyze a specific FFT for the symmetric group.

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The Negs And Regs Of Continued Fractions, Alexander Eustis May 2006

The Negs And Regs Of Continued Fractions, Alexander Eustis

HMC Senior Theses

There are two main aims of this thesis. The first is to further develop and demonstrate applications of the combinatorial interpretation of continued fractions introduced in [Benjamin and Quinn, 2003]. The second is to investigate the theory of negative continued fractions, a relatively unresearched topic. That is, discuss the ways in which they are similar to and different from the regular class, describe how to convert between the two forms, and show that the central theorems concerning regular continued fractions also apply to the negative ones.

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Teaching Time Savers: A Recommendation For Recommendations, Michael E. Orrison Jr. May 2006

Teaching Time Savers: A Recommendation For Recommendations, Michael E. Orrison Jr.

All HMC Faculty Publications and Research

I admit it — I enjoy writing recommendation letters for my students. I like
learning about their hopes and dreams, where they have been and where they want to go. A recommendation letter is an opportunity to remind myself how much my students can grow while they are in college, and how much I have grown as an instructor, advisor, and mentor.

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Foraging Fruit Flies: Lagrangian And Eulerian Descriptions Of Insect Swarming, Joesph Majkut May 2006

Foraging Fruit Flies: Lagrangian And Eulerian Descriptions Of Insect Swarming, Joesph Majkut

HMC Senior Theses

In this work, I seek to model swarms of fruit flies, drosophila melanogaster, whose flights are characterized by straight flight segments interrupted by rapid turns called saccades. These flights are reminiscent of Levy-distributed random walks which are known to lead to efficient search behavior. I build two types of model for swarms of foraging fruit flies, whose behavior depends on swarm density and chemoattractant concentration, using rules inspired by experimentally observed flight patterns. First I will present a Lagrangian model where the path of each individual fly is tracked. I will also consider an Eulerian model where the fruit fly …

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Turing Pattern Dynamics For Spatiotemporal Models With Growth And Curvature, Julijana Gjorgjieva May 2006

Turing Pattern Dynamics For Spatiotemporal Models With Growth And Curvature, Julijana Gjorgjieva

HMC Senior Theses

Turing theory plays an important role in real biological pattern formation problems, such as solid tumor growth and animal coat patterns. To understand how patterns form and develop over time due to growth, we consider spatiotemporal patterns, in particular Turing patterns, for reaction diffusion systems on growing surfaces with curvature. Of particular interest is isotropic growth of the sphere, where growth of the domain occurs in the same proportion in all directions. Applying a modified linear stability analysis and a separation of timescales argument, we derive the necessary and sufficient conditions for a diffusion driven instability of the steady state …

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Matrix Representation Of Knot And Link Groups, Jessica May May 2006

Matrix Representation Of Knot And Link Groups, Jessica May

HMC Senior Theses

In the 1960s French mathematician George de Rham found a relationship between two invariants of knots. He found that there exist representations of the fundamental group of a knot into a group G of upper right triangular matrices in C with determinant one that is described exactly by the roots of the Alexander polynomial. I extended this result to find that the representations of the fundamental group of a link into G are described by the multivariable Alexander polynomial of the link.

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The Singular Values Of The Exponientiated Adjacency Matrixes Of Broom-Tree Graphs, Tracy Powell May 2006

The Singular Values Of The Exponientiated Adjacency Matrixes Of Broom-Tree Graphs, Tracy Powell

HMC Senior Theses

In this paper, we explore the singular values of adjacency matrices {An} for a particular family {Gn} of graphs, known as broom trees. The singular values of a matrix M are defined to be the square roots of the eigenvalues of the symmetrized matrix MTM. The matrices we are interested in are the symmetrized adjacency matrices AnTAn and the symmetrized exponentiated adjacency matrices BnTBn = (eAn − I)T(eAn − I) of the graphs Gn. The application of these matrices in the HITS algorithm for Internet searches suggests that we study whether the largest two eigenvalues of AnTAn (or those of …

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Optimal Control Of A Building During An Earthquake, Kenneth Maples May 2006

Optimal Control Of A Building During An Earthquake, Kenneth Maples

HMC Senior Theses

In this thesis I develop a mathematical model for an apartment building during an earthquake. The movement of the building is restricted to a plane and twisting motions have been assumed negligible. A control system for the building is developed using optimal control techniques. For a quadratic objective functional, the existence of an optimal control is determined and numerical results are generated that show that the controller significantly lowers the chaotic oscillations in the building. The numerical work was done with the Miser3 package for Matlab. Relaxation of different constraints are considered, including multiple controls, varying stories, and different objective …

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