Words make people think, ... but pictures make people feel: The effect negative vs. positive images on charitable behavior

We ran an experiment where the subjects initially played a four-round dictator game, after which each subject was shown either a set of positive images or a set of negative images. Finally the subjects played another four-round dictator game.
The effect of the sign of images shown is clear on the players’ behaviors: positive images have moderate effects on charitable behavior while negative images dramatically increase charity.
We could therefore infer from our experimental results that showing negative images of the Haitian and Chilean catastrophes to the international public would have significant positive impacts on international donations to the victims and the rebuilding programs in both countries

Anti-Miscegenation Laws in the United States

Still another thesis on Rubik’s cube? Is there still something new to write on that puzzle? In this document, we approach the cube with a rather unusual question: “how would you solve the cube if, instead of using the 6 classical rotations, you were restricted to a set of arbitrary moves?” To answer that question, we will dive into group theory. Inspired by some previous work on the factorization of the symmetric group, we have developed an algorithm that answers our initial question. However, being able to solve the cube with any set of moves has a trade-off: while some algorithms solve the cube in 20 moves, ours requires several thousands. One could go further than this thesis by: improving our algorithm, providing rigourous bounds on its complexity, or generalizing the algorithm to the n × n × n cube.

Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction

Ordinary ferroelectrics exhibit a second order phase transition that is characterized by a sharp peak in the dielectric permittivity at a frequency-independent temperature. Furthermore, these materials show a low temperature dielectric relaxation that appears to be a common behavior of perovskite systems. Tetragonal lead zirconate titanate is used here as a model system in order to explore the origin of such an anomaly, since there is no consensus about the physical phenomenon involved in it. Crystallographic and domain structure studies are performed from temperature dependent synchrotron x-ray diffraction measurement. Results indicate that the dielectric relaxation cannot be associated with crystallographic or domain configuration changes. The relaxation process is then parameterized by using the Vogel–Fulcher–Tammann phenomenological equation. Results allow us to hypothesize that the observed phenomenon is due to changes in the dynamic behavior of the ferroelectric domains related to the fluctuation of the local polarization.Postprint (author's final draft

Focal Spot, Fall/Winter 1992

https://digitalcommons.wustl.edu/focal_spot_archives/1062/thumbnail.jp

Focal Spot, Fall/Winter 1989

https://digitalcommons.wustl.edu/focal_spot_archives/1053/thumbnail.jp

Low-density PMMA/MAM nanocellular polymers using low MAM contents: Production and characterization

Low-density nanocellular polymers are required to take advantage of the full potential of these materials as high efficient thermal insulators. However, their production is still a challenging task. One promising approach is the use of nanostructured polymer blends of poly(methyl methacrylate) (PMMA) and a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM), which are useful for promoting nucleation but seem to present a severe drawback, as apparently avoid low relative densities. In this work, new strategies to overcome this limitation and produce low-density nanocellular materials based on these blends are investigated. First, the effect of very low amounts of the MAM copolymer is analysed. It is detected that nanostructuration can be prevented using low copolymer contents, but nucleation is still enhanced as a result of the copolymer molecules with high CO2 affinity dispersed in the matrix, so nanocellular polymers are obtained using very low percentages of the copolymer. Second, the influence of the foaming temperature is studied. Results show that for systems in which there is not a clear nanostructuration, cells can grow more freely and smaller relative densities can be achieved. For these studies, blends of PMMA with MAM with copolymer contents from 10 wt% and as low as 0.1 wt% are used. For the first time, the production strategies proposed in this work have allowed obtaining low density (relative density 0.23) nanocellular polymers based on PMMA/MAM blends. Graphical abstrac

Focal Spot, Fall/Winter 1990

https://digitalcommons.wustl.edu/focal_spot_archives/1056/thumbnail.jp

Reading “Women Don’t Riot” After the Riot: Creating a University-Prison Collaboration

We examine a case study of a collaboration between a University and a Women’s Correctional Institution: an Inside Out college course that brings together incarcerated and traditional students. We analyze the creation of a class in the aftermath of a riot in the region and in the ongoing context of internal and external reforms. We provide specific examples of mistakes, lessons learned, and the impact of our pedagogical values and techniques, and provide links to our class materials. We emphasize communication between the institutions, from the students to instructors, among the instructors, and from instructors to students. In the classroom, we exploit our expertise and our non-expertise as learners together to break down perceived barriers. We also emphasize the value of self-care and recognition of all students as agentic. We conclude with a call for future research that attends to student agency and that examines who benefits from prison-university partnerships