Welcome back to Science Fair, Bwog’s weekly roundup of science events happening around campus. As always, email science@bwog.com if you want your event featured.

Forgotten Promise, Current Peril, & Future Potential of the Internet Trust Architecture

• Monday, May 1, 11 am to 12 pm.
• Online (register here) and in-person (Milstein LL018).
• “The Public Key Infrastructure (PKI) determines the code our computers install, the web sites we recognize as trustworthy, and what apps our phones will accept.   The reliability of the PKI ecosystem depends on the trustworthiness of the Certificate Authorities (CAs), the code, the cryptography, and the selection of keys.  It also depends on the governance structure and human factors. Who decides what roots of trust are shipped as part of browsers and phones, and in the future automobiles, toys, appliances, and airplane components?  How do certificates fail?  Beginning with a machine learning approach to identify failures, then moving to qualitative analyses. I argue for a more nuanced understanding of trust in the Internet ecosystem. The talk includes an overview of emerging standards, current state, and past practice in PKI.” More information here.

What Happened to the Kilogram?

• Monday, May 1, 12 to 1 pm.
• Davis Auditorium.
• “For 130 years, a cylinder made of a platinum-iridium alloy stored near Paris was the official definition of a kilogram, the basic unit of mass. This all changed on May 20, 2019. A kilogram is now defined by a fundamental constant of nature known as the Planck constant (h), which relates the energy of a photon to its frequency: h= 6.62607015 x 10^-34 kilograms times square meters per second.The definition of the kilogram is now connected to the definition of time, realized by atom clocks, and the speed of light. Sounds complicated? In this talk, Ketterle will provide the reasons for changing the definition of the kilogram, give simple explanations of what the new kilogram is conceptually, and explain how objects with exactly known masses can be realized using precision measurements and advanced quantum technology.” More information here.

Medicalizing and Criminalizing Mental Health

• Tuesday, May 2, 12 to 1 pm.
• Online event, register here.
• “Individuals experiencing difficulties while living with a mental health diagnosis are often picked up by law enforcement. They are then taken – as if by coin toss – either to jail or to a hospital. Recent policies in the United States have played a hand in deepening mental health stigma and widening the gap between care that is needed and imposed interventions. This session will explore the way mental illness has routinely been both medicalized and criminalized, the impact of incarceration on mental health at large, and what work is being done to promote harm reduction in New York City and beyond.” More information here.

Astronomy & Astrophysics Graduating Student Colloquium

• Wednesday, May 3, 4:05 to 5:05 pm.
• Pupin 1402.
• A collection of talks from the Spring 2023 Astronomy & Astrophysics graduating class, including “A Unified Survival Criterion for Cloud-Wind Interactions,” “Cosmological constraints from HSC survey first-year data using deep learning,” “An abrupt change in the stellar spin-down law at the fully convective boundary,” and “Electron Energization in Solar Wind Shocks.” Followed by wine and cheese! More information here.

Solving Global Grand Challenges with High Performance Data Analytics

• Friday, May 5, 11 am to 12 pm.
• Online (register here) and in-person (Milstein 111).
• “Emerging real-world graph problems include: detecting and preventing disease in human populations; revealing community structure in large social networks; protecting our elections from cyber-threats; and improving the resilience of the electric power grid. Unlike traditional applications in computational science and engineering, solving these problems at scale often raises new challenges because of the sparsity and lack of locality in the data, the need for additional research on scalable algorithms and development of frameworks for solving these problems on high performance computers, and the need for improved models that also capture the noise and bias inherent in the torrential data streams. In this talk, Bader will discuss the opportunities and challenges in massive data-intensive computing for applications in computational science and engineering.” More information here.

Motion Planning Around Obstacles with Graphs of Convex Sets

• Friday, May 5, 11 am to 12 pm.
• Lerner Hall, Satow Room.
• “In this talk, I’ll describe a new approach to planning that strongly leverages both continuous and discrete/combinatorial optimization. The framework is fairly general, but I will focus first on a particular application of the framework to planning continuous curves around obstacles. Traditionally, these sorts of motion planning problems have either been solved by trajectory optimization approaches, which suffer with local minima in the presence of obstacles, or by sampling-based motion planning algorithms, which can struggle with derivative constraints and sample-complexity in very high dimensions. In the proposed framework, called Graphs of Convex Sets (GCS), we can recast the trajectory optimization problem over a parametric class of continuous curves into a problem combining convex optimization formulations for graph search and for motion planning.” More information here.

Pushed to extremes: Probing protein and ligand conformations with biophysical perturbations

• Friday, May 5, 4 to 5:30 pm.
• Havemeyer 209.
• “Proteins do not adopt a single structure, but rather a fluctuating ensemble of conformations which collectively encode biological functions such as ligand binding, enzyme catalysis, and allosteric regulation.  However, it has been difficult to experimentally resolve alternative conformations of proteins and ligands at high resolution, limiting efforts to elucidate the fundamental connections between structural dynamics and function.  To help address this gap, my lab leverages a unique combination of avant-garde X-ray crystallography experiments and downstream computational modeling approaches to reveal distinct conformations of both proteins and bound small-molecule ligands.  Here, I will discuss two recent projects from our group in these areas.” More information here.

Long-term Perspectives on Deer Management in China

• Friday, May 5, 4:30 to 6:30 pm.
• Faculty House, register here.
• “For thousands of years, deer were one of the main sources of food, antler, and skins for people in North China, but the ecological significance of this remains unexplored. People in Neolithic and Early Bronze Age China modified landscapes in significant ways through earthworks, irrigation, and other agricultural practices. Particularly, people often used controlled fires to clear agricultural fields, abandoning fields after a few years and moving on to new land. Frequent shifting of farmed lands created a mosaic of vegetation types that is the ideal habitat for deer, and the faunal remains excavated at archaeological sites in China make clear that people hunted and ate a lot of deer. This paper examines zooarchaeological, textual, and paleoenvironmental evidence to explore the relationship between humans, deer, and the landscape. Ancient people were probably aware of what types of vegetation attracted deer and intentionally managed their landscapes to make them better deer habitat. However, after domesticated cattle, sheep, and goats arrived from Western Asia, people had less need for deer. As farming intensified, human impact on the landscape grew and deer were eliminated from people’s diets and from the landscape.” More information here.

Climate Imaginations Spring Festival

• Saturday, May 6, 2 to 6 pm.
• Lenfest Plaza, register here.
• “Responding to climate change requires us to act creatively in community: with hope, grounded in action. This festival is an invitation to build connections, engage with climate stories and art, and cultivate joy and strength: all critical ingredients in the journey that lies ahead. Enjoy films, panel discussions, meditations, workshops, displays, and installation art and get to know the Climate Imaginations community at Columbia and beyond.” More information here.

Header image via author