Digital Commons Network^™

Is Empathy Gendered And If So, Why? An Approach From Feminist Psychological Anthropology, Claudia Strauss

Pitzer Faculty Publications and Research

Difference feminists have argued that women have special virtues. One such virtue would seem to be empathy, which has three main components: imaginative projection, awareness of the other's emotions, and concern. Empathy is closely related to identification. Psychological research and the author's own study of women's and men's talk about poverty and welfare use in the United States demonstrate women's greater empathic concern. However, some cross-cultural research shows greater sex differences in empathy in the United States than elsewhere. This combination of findings (women tend to demonstrate greater empathic concern, but this typical difference varies cross-culturally) requires a complex biocultural …

Newton, Maclaurin, And The Authority Of Mathematics, Judith V. Grabiner

Pitzer Faculty Publications and Research

Sir Isaac Newton revolutionized physics and astronomy in his Principia. How did he do it? Would his method work on any area of inquiry, not only in science, but also about society and religion? We look at how some Newtonians, most notably Colin Maclaurin, combined sophisticated mathematical modeling and empirical data in what has come to be called the "Newtonian Style." We argue that this style was responsible not only for Maclaurin’s scientific success but for his ability to solve problems ranging from taxation to insurance to theology. We show how Maclaurin’s work strengthened the prestige of Newtonianism and …

Respiratory Symptoms In Relation To Residential Coal Burning And Environmental Tobacco Smoke Among Early Adolescents In Wuhan, China: A Cross-Sectional Study, C. Anderson Johnson, Jiang Xia, Päivi M. Salo, Yan Li, Grace E. Kissling, Edward L. Avol, Chunhong Liu, Stephanie J. London

CGU Faculty Publications and Research

Background

Cigarette smoking and coal burning are the primary sources of indoor air pollution in Chinese households. However, effects of these exposures on Chinese children's respiratory health are not well characterized.

Methods

Seventh grade students (N = 5051) from 22 randomly selected schools in the greater metropolitan area of Wuhan, China, completed an in-class self-administered questionnaire on their respiratory health and home environment.

Results

Coal burning for cooking and/or heating increased odds of wheezing with colds [odds ratio (OR) = 1.57, 95% confidence interval (CI): 1.07–2.29] and without colds (OR = 1.44, 95% CI: 1.05–1.97). For smoking in the home, …

Diversity And Homogeneity In American Culture: Teaching And Theory, Claudia Strauss

Pitzer Faculty Publications and Research

In teaching, as in any kind of cultural production, you can look at content, or you can look at reception. Here I want to talk about both: the content of what to say about diversity and sharing in U.S. culture, and how that may be received.

A (Not So) Complex Solution To A² + B² = Cⁿ, Arnold M. Adelberg, Arthur T. Benjamin, David I. Rudel '99

All HMC Faculty Publications and Research

No abstract provided in this article.

Random Walks On The Torus With Several Generators, Timothy Prescott '02, Francis E. Su

All HMC Faculty Publications and Research

Given n vectors {_i} ∈ [0, 1)^d, consider a random walk on the d-dimensional torus ^d = ℝ^d/ℤ^d generated by these vectors by successive addition and subtraction. For certain sets of vectors, this walk converges to Haar (uniform) measure on the torus. We show that the discrepancy distance D(Q*^k) between the kth step distribution of the walk and Haar measure is bounded below by D(Q*^k) ≥ C₁k^−n/2, where C₁ = C(n, d) is …

On The Polarization Of Closed Strings By Ramond-Ramond Fluxes, Vatche Sahakian

All HMC Faculty Publications and Research

In the Green-Schwarz formalism, the closed string worldsheet of the IIB theory couples to Ramond-Ramond (RR) fluxes through spinor bilinears. We study the effect of such fluxes by analyzing the supersymmetry transformation of the worldsheet in general backgrounds. We show that, in the presence RR fields, the closed string can get `polarized', as the spinors acquire non-zero vevs in directions correlating with the orientation of close-by D-branes. Reversing the argument, this may allow for worldsheet configurations—with non-trivial spinor structure—that source RR moments.

Heights And Diophantine Problems, Lenny Fukshansky

CMC Faculty Publications and Research

Lecture given at Rice University, September 2004.

Improved Phase Modulation For An En-Face Scanning Three-Dimensional Optical Coherence Microscope, Barbara M. Hoeling, Mary E. Peter, Daniel C. Petersen, Richard C. Haskell

All HMC Faculty Publications and Research

We have previously described an inexpensive method for modulating the interferometer of an en-face scanning, focus-tracking, three-dimensional optical coherence microscope (OCM). In this OCM design, a reference mirror is mounted on a piezoelectric stack driven at a resonance frequency of about 100 kHz. We perform a partial discrete Fourier transform of the digitally sampled output fringe signal. In the original design, we obtained the amplitude of the backscattered light by summing the powers in the fundamental (1ω) and first harmonic (2ω) of the modulation frequency. We used the particular piezoamplitude that eliminates the effects of interferometer phase drift. However, as …

Human Stick Balancing: Tuning Lèvy Flights To Improve Balance Control, Juan Luis Cabrera, John Milton

WM Keck Science Faculty Papers

State-dependent, or parametric, noise is an essential component of the neural control mechanism for stick balancing at the fingertip. High-speed motion analysis in three dimensions demonstrates that the controlling movements made by the fingertip during stick balancing can be described by a Lévy flight. The Lévy index, , is approximately 0.9; a value close to optimal for a random search. With increased skill, the index does not change. However, the tails of the Lévy distribution become broader. These observations suggest a Lévy flight that is truncated by the properties of the nervous and musculoskeletal system; the truncation decreasing as skill …

Immunogold Labeling To Enhance Contrast In Optical Coherence Microscopy Of Tissue Engineered Corneal Constructs, Chris B. Raub, Elizabeth J. Orwin, Richard C. Haskell

All HMC Faculty Publications and Research

Our lab has used an optical coherence microscope (OCM) to assess both the structure of tissue-engineered corneal constructs and their transparency. Currently, we are not able to resolve cells versus collagen matrix material in the images produced. We would like to distinguish cells in order to determine if they are viable while growing in culture and also if they are significantly contributing to the light scattering in the tissue. In order to do this, we are currently investigating the use of immunogold labeling. Gold nanoparticles are high scatterers and can create contrast in images. We have conjugated gold nanoparticles to …

Putnam, Pizza & Problem Solving, Andrew J. Bernoff, Francis E. Su

All HMC Faculty Publications and Research

Ok, here's a difficult question for you.. How can you get roughly 10% of the student body at your college to get up early on a Saturday and spend six hours working on an incredibly difficult exam for which many will get a score of zero?

Visualizing Early Frog Development With Motion-Sensitive 3-D Optical Coherence Microscopy, Richard C. Haskell, Mary E. Williams, Daniel C. Petersen, Barbara M. Hoeling, Andrew J. Schile, J. D. Pennington, M. G. Seetin, J. M. Castelaz, Scott E. Fraser, Cyrus Papan, Hongwu Ren, Johannes F. De Boer, Zhongping Chen

All HMC Faculty Publications and Research

A motion-sensitive en-face-scanning 3-D optical coherence microscope (OCM) has been designed and constructed to study critical events in the early development of plants and animals. We describe the OCM instrument and present time-lapse movies of frog gastrulation, an early developmental event in which three distinct tissue layers are established that later give rise to all major organ systems. OCM images constructed with fringe-amplitude data show the mesendoderm migrating up along the blastocoel roof, thus forming the inner two tissue layers. Motion-sigma data, measuring the random motion of scatterers, is used to construct complementary images that indicate the presence of Brownian …

Synaptic Transformations Underlying Highly Selective Auditory Representations Of Learned Birdsong, Melissa J. Coleman, Richard Mooney

WM Keck Science Faculty Papers

Stimulus-specific neuronal responses are a striking characteristic of several sensory systems, although the synaptic mechanisms underlying their generation are not well understood. The songbird nucleus HVC (used here as a proper name) contains projection neurons (PNs) that fire temporally sparse bursts of action potentials to playback of the bird's own song (BOS) but are essentially silent when presented with other acoustical stimuli. To understand how such remarkable stimulus specificity emerges, it is necessary to compare the auditory-evoked responsiveness of the afferents of HVC with synaptic responses in identified HVC neurons. We found that inactivating the interfacial nucleus of the nidopallium …

Femtosecond Spectrotemporal Magneto-Optics, J.-Y. Bigot, L. Guidoni, E. Beaurepaire, Peter N. Saeta

All HMC Faculty Publications and Research

A new method to measure and analyze the time and spectrally resolved polarimetric response of magnetic materials is presented. It allows us to study the ultrafast magnetization dynamics of a CoPt₃ ferromagnetic film. The analysis of the pump-induced rotation and ellipticity detected by a broad spectrum probe beam shows that magneto-optical signals predominantly reflect the spin dynamics in ferromagnets.

A Liouville-Gelfand Equation For K-Hessian Operators, Jon T. Jacobsen

All HMC Faculty Publications and Research

In this paper we establish existence and multiplicity results for a class of fully nonlinear elliptic equations of k-Hessian type with exponential nonlinearity. In particular, we characterize the precise dependence of the multiplicity of solutions with respect to both the space dimension and the value of k. The choice of exponential nonlinearity is motivated by the classical Liouville-Gelfand problem from combustible gas dynamics and prescribed curvature problems.

La Belle Rêve, Nancy Macko

Scripps Faculty Publications and Research

Artist and academic Nancy Macko discusses her sabbatical residency in Brittany, France.

An Experimental Study Of Micron-Scale Droplet Aerosols Produced Via Ultrasonic Atomization, Thomas D. Donnelly, J. Hogan '03, A. Mugler '04, N. Schommer '04, M. Schubmehl '02, Andrew J. Bernoff, B. Forrest '02

All HMC Faculty Publications and Research

In the last 10 years, laser-driven fusion experiments performed on atomic clusters of deuterium have shown a surprisingly high neutron yield per joule of input laser energy. Results indicate that the optimal cluster size for maximizing fusion events should be in the 0.01–μm diameter range, but an appropriate source of droplets of this size does not exist. In an attempt to meet this need, we use ultrasonic atomization to generate micron-scale droplet aerosols of high average density, and we have developed and refined a reliable droplet sizing technique based on Mie scattering. Harmonic excitation of the fluid in …

Book Review: "Yet With A Steady Beat: Contemporary U.S. Afrocentric Biblical Interpretation" By Randall C. Bailey, Vincent L. Wimbush

CGU Faculty Publications and Research

Written at different times for different purposes and occasions, by African American scholars who are differently oriented and differently situated, eight essays have been collected and edited by biblical scholar Randall C. Bailey with a particular focus and purpose in mind. Such focus and purpose are not elaborated upon in the editor's slim introduction. Aside from the issue of the quality of the essays - of uneven quality, as is the case, as everyone knows, with almost all collected essays - what is at stake in this volume, and all volumes that are collections of essays by different authors, is …

Patterning Polymer Thin Films: Lithographically Induced Self Assembly And Spinodal Dewetting, Regina C. Carns

Pomona Senior Theses

In an age in which the microchip is ubiquitous, the rewards for novel methods of microfabrification are great, and the vast possibilities of nanotechnology lie just a little ahead. Various methods of microlithography offer differing benefits, and even as older techniques such as optical lithography are being refined beyond what were once considered their upper limits of resolution, new techniques show great promise for going even further once they reach their technological maturity. Recent developments in optical lithography may allow it to break the 100-nm limit even without resorting to x-rays.

Representation Theoretical Methods In Image Processing, William Chang

HMC Senior Theses

Image processing refers to the various operations performed on pictures that are digitally stored as an aggregate of pixels. One can enhance or degrade the quality of an image, artistically transform the image, or even find or recognize objects within the image. This paper is concerned with image processing, but in a very mathematical perspective, involving representation theory. The approach traces back to Cooley and Tukey’s seminal paper on the Fast Fourier Transform (FFT) algorithm (1965). Recently, there has been a resurgence in investigating algebraic generalizations of this original algorithm with respect to different symmetry groups. My approach in the …

Representation Theoretical Approach To N-Candidate Voting, Grant Clifford

HMC Senior Theses

Voting theory as been explored mathematically since the 1780’s. Many people have tackled parts of it using various tools, and now we shall look at it through the eyes of a representation theorist. Each vote can be thought of as a permutation of the symmetric group, Sn, and a poll is similar to a linear combination of these elements. Specifically, we will focus on translating and generalizing the works of Donald Saari into more algebraic terms to discover not just one space, but a whole isotypic component essential to positional voting.

Alexander Polynomials Of Tunnel Number One Knots, Robert Gaebler

HMC Senior Theses

Every two-bridge knot or link is characterized by a rational number p/q, and has a fundamental group which has a simple presentation with only two generators and one relator. The relator has a form that gives rise to a formula for the Alexander polynomial of the knot or link in terms of p and q [15]. Every two-bridge knot or link also has a corresponding “up down” graph in terms of p and q. This graph is analyzed combinatorially to prove several properties of the Alexander polynomial. The number of two-bridge knots and links of a given crossing number are …

Toeplitz Operators On Locally Compact Abelian Groups, David Gaebler

HMC Senior Theses

Given a function (more generally, a measure) on a locally compact Abelian group, one can define the Toeplitz operators as certain integral transforms of functions on the dual group, where the kernel is the Fourier transform of the original function or measure. In the case of the unit circle, this corresponds to forming a matrix out of the Fourier coefficients in a particular way. We will study the asymptotic eigenvalue distributions of these Toeplitz operators.

Modeling Cancer Cell Response To Immunotherapy, Eric Harley

HMC Senior Theses

Significant work has been done modeling cancerous tumor growth and response to therapy under certain simplifying assumptions, specifically, the assumption of spatial homogeneity. We have chosen a spatially heterogenous model for cancer cell growth using a hybrid Lattice-Gas Cellular Automata method. Cell mitosis, apoptosis, and necrosis are explicitly modeled along with the diffusion of nutrients and a necrotic signal. The model implementation is verified qualitatively and is modified to execute on a parallel computer.

Behavior Of Coupled Automata, Reuben Gann, Jessica Venable, Eric J. Friedman, Adam S. Landsberg

WM Keck Science Faculty Papers

We study the nature of statistical correlations that develop between systems of interacting self-organized critical automata (sandpiles). Numerical and analytical findings are presented describing the emergence of "synchronization" between sandpiles and the dependency of this synchronization on factors such as variations in coupling strength, toppling rule probabilities, symmetric versus asymmetric coupling rules, and numbers of sandpiles.

Cultural Standing In Expression Of Opinion, Claudia Strauss

Pitzer Faculty Publications and Research

This article explores an underappreciated pragmatic constraint on the expression of opinions: When expressing an opinion on a topic that has been previously discussed, a speaker should correctly indicate the cultural standing of that view in the relevant opinion community. This Bakhtinian approach to discourse analysis is contrasted with conversation analysis, politeness theory (Brown & Levinson, 1987), and analysis of epistemic modality. Finally, indicators of four points on the cultural standing continuum (highly controversial, debatable, common opinion, and taken for granted) are illustrated with examples from American English usage.

Review: Pamela O. Long, Openness, Secrecy, Authorship: Technical Arts And The Culture Of Knowledge From Antiquity To The Renaissance (Baltimore And London, 2001), Andre Wakefield

Pitzer Faculty Publications and Research

Reviewed work: Pamela O. Long. Openness, Secrecy, Authorship: Technical Arts and the Culture of Knowledge from Antiquity to the Renaissance. Baltimore: Johns Hopkins University Press, 2001. Pp. xii+364. $55.

Closed Strings In Ramond-Ramond Backgrounds, Vatche Sahakian

All HMC Faculty Publications and Research

We write the IIB Green-Schwarz action in certain general classes of curved backgrounds threaded with Ramond-Ramond fluxes. The fixing of the kappa symmetry in the light-cone gauge and the use of supergravity Bianchi identities simplify the task. We find an expression that truncates to quartic order in the spacetime spinors and relays interesting information about the vacuum structure of the worldsheet theory. The results are particularly useful in exploring integrable string dynamics in the context of the holographic duality.

Double Excitations Within Time-Dependent Density Functional Theory Linear Response, Neepa T. Maitra, Fan Zhang, Robert J. Cave, Kieron Burke

All HMC Faculty Publications and Research

Within the adiabatic approximation, time-dependent density functional theory yields only single excitations. Near states of double excitation character, the exact exchange–correlation kernel has a strong dependence on frequency. We derive the exact frequency-dependent kernel when a double excitation mixes with a single excitation, well separated from the other excitations, in the limit that the electron–electron interaction is weak. Building on this, we construct a nonempirical approximation for the general case, and illustrate our results on a simple model.