Professor Cacey Bester (Physics & Astronomy)
Tuesday, September 12, 2023
4:30pm, Scheuer Room
The Physics of Sand: How Granular Materials Creep, Jam, and Shear
Examples of granular materials exist in abundance, from rice and cereal to sand and rocks. These particulate systems seem simple; they consist of dry, rigid grains that interact by contact force. However, granular materials present many questions to address, such as how force distributes heterogeneously among grains and how flow behavior can readily change between solid-like and fluid-like. Our experimental lab uses an imaging technique to probe this behavior of granular materials at the scale of a single grain. In this talk, I will describe the use of this technique and our experiments to better understand the fundamental physics of granular materials.
Professor Amanda Luby (Mathematics & Statistics)
Thursday, October 12, 2023
4:30pm, Scheuer Room
Quantifying Variability in Forensic Decision-Making
Forensic science often involves the evaluation of crime-scene evidence, such as fingerprints or DNA, to determine whether it matches a known-source sample from a particular person. However, when given the same evidence, different forensic examiners may reach different opinions or use different criteria to arrive at their opinions. Any variability among examiners could have massive downstream impact: among Innocence Project exonerations, the misapplication of forensic science has contributed to more than half of known wrongful convictions. The current approach to characterizing uncertainty in forensic decision-making has largely centered around conducting error rate studies (in which examiners evaluate evidence from a known source) and calculating aggregated error rates. This approach is not ideal for comparing examiner performance, as decisions are not always unanimous and error frequency varies depending on the quality of the physical evidence. In this talk, I’ll discuss more sophisticated statistical models for quantifying types of variability in forensic decision making, outline challenges of applying these models in practice, and highlight the implications of these findings for the criminal justice system.
Professor Paloma Checa-Gismero (Art, Art History, Latinx & Latin American, Gender & Sexuality, & Environmental Studies)
Thursday, November 16, 2023
4:30 pm
Scheuer Room, Kohlberg Hall
Biennial Boom: Making Contemporary Art Global
In Biennial Boom, Paloma Checa-Gismero traces an archeology of art biennials and uncovers the processes that prompted these exhibitions to become the contemporary art world’s defining events at the end of the 20th century. Returning to the early post-Cold War years, Checa-Gismero examines the early iterations of three well-known biennials at the borders of North Atlantic liberalism: the Bienal de La Habana, inSITE, and Manifesta. This research draws on archival and oral history fieldwork in Cuba, Mexico, the US/Mexico borderlands, and the Netherlands, and shows how these biennials reflected a post-Cold War optimism for a pacified world by which artistic and knowledge production would help mend social, political, and cultural divisions. Checa-Gismero argues that biennials facilitated the conversion of subaltern aesthetic genealogies into forms that were legible to a nascent cosmopolitan global elite—all under the pretense of cultural exchange. By outlining how early biennials set the basis for what is now recognized as “global contemporary art,” Checa-Gismero intervenes in previous accounts of the contemporary art world in order to better understand how it became the exclusionary, rarified institution of today.
Professor Karen Chan (Biology)
Thursday, February 1, 2024
4:30pm, Scheuer Room
Growing up in a changing ocean
Climate change is posing significant threats to marine ecosystems. Many marine organisms have complex life histories and rely on a small, weakly swimming early life stage for dispersal. Our lab combines engineering techniques with biological experiments to investigate how marine organisms cope with a changing ocean. In particular, to adapt through natural selection, variability between individuals within a population is a key component. Parent legacy is one way through which variability in performance is instilled. Focusing on the extreme event, a marine heatwave, this talk will discuss how parental experience influences gamete qualities, and thus, fertilization kinetics.
Professor Ian Whitehead (Mathematics & Statistics)
Thursday, April 4, 2024
4:30pm, Scheuer Room
Circle Packings: A Field Guide
This talk is about the art and science of putting smaller circles inside bigger ones. I will give a typology of fractal circle packings: how they are constructed, what properties they have, and why they raise interesting questions for geometry and number theory. These circle packings originate with the ancient Greek mathematician Apollonius of Perga, but many of their features were discovered and proven by Swarthmore students in the last five years.
