Archive of Talks
2006-07
2005-06
2004-05
2003-04
2002-03
2006-07
Date and Time:Tuesday, April 24, 2007 at 8:00PM in Science Center 101
The FFT - An Algorithm the Whole Family Can Use
Dr. Daniel Rockmore, Professor of Mathematics, Darthmouth College
The Fast Fourier Transform, or FFT, is one of the most ubiquitous
algorithms in all of computational mathematics. In this talk we'll
explore the FFT from its astronomical origins in the prediction of
celestial orbits, to its modern instantiation as the primary tool of
digital signal processing, and then move on to its generalizations as
a basic scheme for data analysis in the presence of symmetry - i.e.,
group theory. We'll see how this more general framework has proved
useful in a variety of areas including biology, robotics, and even
quantum computing.
Date and Time:Tuesday, January 30, 2007 at 8:00PM in Science Center 199
Strange Bits: Quantum Computing and the Search for New Quantum Algorithms
Dr. Lee Spector, Professor of Computer Science, School of Cognitive Science, Hampshire College
Quantum mechanics may provide the next major leap in computer power, allowing us to produce "quantum computers" that do things beyond the capabilities of even the fastest possible conventional computers. But the power of quantum computing is still poorly understood, emerging as it does from bizarre and counterintuitive features of the microscopic world. For example, quantum computers must be carefully isolated from their
environments lest they be observed in action, which would destroy their results. Even more strangely, quantum calculations that are not performed can have as much impact on the overall result of a computation as those that are. In this talk I will present one view of the fundamental source of this new computational power, and I will also describe ways in which software technologies based on Darwinian processes of random variation and selection can be used to automatically discover new quantum computing algorithms.
Date and Time:Tuesday, November 28, 2006 at 8:00PM in Science Center 101
Dr. William Bonnez and Dr. Robert Rose, Professors of Medicine, University of Rochester
Dr. Bonnez will provide a general overview of human papillomaviruses (HPV), the causative agents of uterine cervical cancer, genital warts, and other diseases. He will discuss the frequency and economic burden of these conditions, how the virus is transmitted, the natural history of infection, and current methods utilized for prevention and treatment. In the second half of the presentation, Dr. Bonnez's colleague and co-worker in the development of the vaccine, Dr. Rose, will describe the development, from the laboratory bench to the clinical world, of the recently approved HPV virus-like particle (VLP) vaccine that has demonstrated efficacy in preventing the precursor lesions of cervical cancer and other genital cancers, as well as genital warts, in women.
2005-06
Date and Time:Monday, May 22, 2006 at 7:00 PM in the Science Center, beginning with a reception in the Eldridge Commons, with the talk in room 101 at 8:00 PM
The annual, end-of-year Strawberry Festival: Astrophysics in the Laboratory
Prof. Michael Brown, Department of Physics and Astronomy, Swarthmore College
Modern laboratory techniques have recently enabled scientists to reproduce astrophysically relevant conditions in the laboratory. Intense laser pulses can reproduce conditions relevant in supernovae and astrophysical jets. High voltage, high current pulses of electricity can heat ionized gas (called plasma) to conditions found on the surface and corona of the sun. Typically, these conditions can only be reproduced in the laboratory for a short time (nanoseconds to microseconds) while conditions in astrophysical contexts can persist for millions of years.
I'll discuss several questions posed by solar physics and astrophysics and describe how these questions are being addressed in the laboratory. The questions include: How do stars burn so hot for so long? How do the sun and planets generate magnetic fields? Why is the sun's atmosphere (corona) 1000 times hotter than its surface (photosphere)? How do astrophysical objects generate energetic particles (cosmic rays)? How do astrophysical disks also generate extended magnetized jets sometimes a million light years long? These questions are related and are being addressed at a facility at Swarthmore College called the Swarthmore Spheromak Experiment (or SSX).
Date and Time: Thursday, February 23, 2006 at 8:00 PM in the Cunniff Lecture Hall (Science Center room 199)
Human Pheromones: What Do We Communicate About Ourselves by the Chemical Signals We Release?
Dr. George Preti, Member, Monell Chemical Senses Center, Philadelphia and Adjunct Professor, Department of Dermatology School of Medicine, University of Pennsylvania
and
Dr. Charles Wysocki, Member, Monell Chemical Senses Center, Philadelphia and Adjunct Professor, Department of Biology, School of Veterinary Medicine, University of Pennsylvania
Scientists are interested in human scent because a subset of the odors that we produce may convey significant information to other humans. These special odors, first identified in insects, are termed pheromones. Scores of invertebrate pheromones have been identified and some have been incorporated into commercially available products, such as pheromone traps for pest insects. A popular idea is that there are human pheromones, which have been incorporated into a plethora of products generally focused upon increasing one?s sexual prowess; however, the biomedical evidence to support this is lacking. Importantly, there is evidence that humans do produce pheromones, but they are not sex attractants as suggested by internet ads. Human chemosignals appear to affect menstrual cycle length and timing as well as mood and scent- recognition of kin; human body odors also contain information about gender and sexual orientation. These latter distinctions can be used to choose a potential mate by smelling an individual?s unique, genetically determined "odorprint." Our continuing research is examining the chemistry of human chemical communication and the effects that human body odors may have upon others.
For further information, see this article about Professor Preti and Wysocki's work.
Date and Time: Tuesday, November 29, 2005 at 8:00 PM in Science Center room 101
Causation and Discrimination: What Can We Learn From Statistics?
Prof. Stephen Fienberg, Carnegie Mellon University
Department of Statistics and the Center for Automated Learning and Discovery
Almost every public debate over policy or science has at its heart a question or conclusion about causation. Here are a few examples:
- Does Wal-Mart discriminate against its women employees?
- Was race at the root of FEMA's lack of responsiveness in New Orleans?
- Does smoking cause lung cancer and other diseases?
- Does Thimerisol in vaccines cause autism?
- Does the treatment of depression in teenagers with SSRIs lead to increased rates of suicide?
For over a century users of statistics were cautioned that "association isn't causation." Through a series of practical and current controversial issues, we will explore how statistics now formulates issues of causation and the extent to which it can contribute to the resolution of these questions. In particular, we will consider the measurement of discrimination from the perspective of statistical causation.
For further information, see Professor Fienberg's webpage.
Date and Time: Thursday, September 29, 2005 at 8:00 PM in Science Center room 101
The Nature of Learning and the Functional Architecture of the Brain
Prof. C. Randall Gallistel, Rutgers University
Department of Psychology
Two different conceptions of learning currently contend, the cognitive science conception and the neuroscience conception. In the first, learning is the extraction from experience of information about the world, which is carried forward in memory to inform subsequent behavior. In the second, learning is a remolding of a plastic brain by experience to make it better adapted to the experienced world. These conceptions imply different functional architectures for the brain. In the first, the brain has the architecture of a Turing machine; in the second, it has the architecture of a switching network. The latter architecture lacks elements essential to the realization of computation as we currently understand it. The lecture reviews simple behavioral evidence drawn from the rat, mouse and pigeon timing literature and the literature on insect navigation implying that the brain must have a Turing architecture. In particular it must have a memory that carries information forward in time and makes it accessible to computations not foreseen at the time the information was laid down. Our current ignorance about how such a memory might be neurobiologically implemented is a major contributor to the conceptual chasm between cognitive science and neuroscience.
For further information, see Professor Gallistel's webpage.
2004-05
Date and Time: Tuesday, May 24, 2005 at 8:00 PM in Science Center room 101 - reception with strawberries beginning at 7:00 PM in the Commons
How Guessing Can Tell You Where You Are
Prof. Bruce Maxwell, Swarthmore College
Department of Engineering
One of the major tasks in robotics is givng the robot the ability to build a map of the local environment and then place itself accurately on the map. This is one of the classic chicken and the egg problems: you can't make a map without knowing where you are, and you can't know where you are without a map. Recent work in robotics has shown us that a good way to simultaneously build maps and localize the robot is to guess intelligently. The hard parts are figuring out how to make an intelligent set of guesses and then deciding which guesses are best. In this talk I'll give a brief overview of a technique called particle filters and how we can apply them to the task of simultaneous mapping and localization on a mobile robot.
For further information, see Professor Maxwell's webpage.
Date and Time: Wednesday, March 16, 2005 at 4:30PM in Science Center room 101 - reception to follow
How Flies Fly
Michael Dickinson, California Institute of Technology
Zarem Professor of Bioengineering
Whether circling garbage cans or cruising through alpine meadows, flies impress us with their aerial agility. Rapid sensory processing, efficient muscles, novel aerodynamics, and a robust control system collectively make flies the most sophisticated flying machines on the planet. Recent advances in physics, engineering, and biology have increased greatly our understanding of these common, but under appreciated creatures. Flies search and explore their environment using a series of straight flight segments interspersed with stereotyped changes in heading termed saccades. Using a combination of methods, we have investigated both the sensory signals that trigger and control these rapid turns as well as the aerodynamic means by which the animals produce them. Results from these experiments provide insight into how brains control complex behavior and may even lead to the construction of a new class of miniature flying robots.
For further information, see Professor Dickinson's webpage.
Date and Time: Thursday, January 27, 2005 at 8PM in Science Center room 101
Bioterrorism: The Threat and Biodefense Challenges
Prof. Ronald M. Atlas, University of Louisville
Graduate Dean and Co-Director Center for Deterrence of Biowarfare and Bioterrorism
In the aftermath of the attacks of 9/11/2001 and the ensuing anthrax attacks, great attention has been focused on national security and biological research. Bioterrorism represents a significant threat. Within the United States there have been major changes in science policy aimed at enhancing protection against bioterrorism, ranging from greatly increased funding of biodefense research and revitalization of the Nation's public health infrastructure to restrictions on the conduct of life science research involving biothreat agents and constraints on communication of study results that could be misused by terrorists. This research must be conducted in a safe and ethical manner, which is particularly challenging given that biothreat agents, such as smallpox virus, are especially dangerous and can be used as weapons of mass terror. Complying with public policies, such as those engendered in the USA Patriot Act and the Biopreparedness Act, both of which contain provisions that restrict access to select biothreat agents, is challenging. The challenge of constraining dangerous information has been confronted in the physical sciences, resulting in a system of classified research. But the life sciences, for the most part, have remained open. Defining dangerous research in the life sciences and finding ways of preventing misuse is especially challenging - we must avoid censorship and restrictions that hinder biomedical advances while adding layers of protection demanded by the public.
For further information, see Professor Atlas's webpage.
Date and Time: Tuesday, November 9, at 8PM in the Scheuer Room in Kohlberg
Automatic Face Detection and Recognition: Technical Challenges and Societal Implications
Prof. Jim Rehg, Georgia Institute of Technology
Over the past fifteen years, the computer vision community has made rapid progress in the ability to automatically detect and recognize faces in images and video using computer algorithms. Within the vision research community, these successes have created renewed excitement for the prospect of using data-driven learning techniques to tackle difficult perceptual problems. Within society at large, these successes and others have fueled significant investment in biometric technologies, as well as significant concerns about their threat to privacy and civil liberties.
In this talk Prof. Rehg will review the current state of face detection and recognition technology, and discuss the limitations of existing methods. His presentation will include a live demo of a real-time face detection system. He will also discuss what is known about human performance at these tasks. He will use the context of this understanding of human and machine performance to frame the on-going debate over surveillance and privacy.
For further information, see Professor Rehg's biography and webpage.
2003-04
Date and Time: Tuesday, May 25, 2004, in the Science Center Lecture Hall (room 101) - our annual strawberry festival.
Prof. Amy Bug
Swarthmore College
Department of Physics
"Even the moon's frightened of me!" Science and Scientists in the Movies
Western literature, fact-based magazines, the movies, and in the minds of many nonscientists; scientists are portrayed in some rather interesting ways. Some of the stereotypes are (Haynes, 1994):
- alchemist
- absent-minded professor
- unfeeling loner
- hero
- helpless victim of science
- idealist
We'll view some images and some film clips from Hollywood classics. We will discuss as a group why these larger-than-life images, both glamorous and villainous, might be so persistent in our culture.
More about Prof. Bug and her research.
Date and Time: Wednesday, February 11, 2004, 8:00 PM in the Science Center Lecture Hall (rm. 101).
Prof. Max Tegmark
Department of Physics
University of Pennsylvania
"Parallel Universes"
The borderline between science and science fiction has gradually shifted to bring once controversial ideas like atoms and black holes into the realm of serious scientific research, and parallel universes may now be going the same way. I survey the latest theoretical and observational evidence for parallel universes, and discuss what they would be like to inhabit. I argue that there may even be a four-level hierarchy of multiverses. In the standard cosmological model where space is infinite, there should be an identical copy of you about ten to the power 100,000,000,000,000,000,000,000,000,000 yards from here.
You can read Prof. Tegmark's recent article on parallel universes in Scientific American and also view his multiverses webpage.
Date and Time: Thursday, October 30, 2003, 8:00 PM in the Science Center Lecture Hall (rm. 101).
Susan Marie Frontczak ('77)
StorySmith
"A Living History of Marie Curie"
Program Abstract:
This one-woman drama exposes the struggles and triumphs of Madame Marie Curie (nee Maria Sklodowska) - an academically impassioned, vehemently private, fervently Polish scientist, mother, and teacher. From the political oppression of her childhood, to scientific realization and fame, to the tragedy that forced her into single motherhood as well as further world prominence, Manya's story reveals a compelling journey.
This program honors a preeminent woman of science: discoverer of radium and radioactivity, first European woman to earn a doctorate in the sciences, first woman to lecture at the Sorbonne, and winner of two Nobel Prizes. Audiences re-live the extraordinary collaboration between husband and wife, Pierre and Marie, companion scientists, who worked with the medical community to establish the first successful treatments of cancer. This program honors the ethic of scientific altruism. The Curies declined to patent their methods, insisting that to profit from the discovery of radium would be contrary to the scientific spirit. And, this program honors Manya's Polish heritage - much neglected not only now, but in her own life, to her own dismay. Whether looking at Marie within her historical context or through the lens of a new millennium, this is a life that challenges our assumptions about what one person can achieve and the responsibilities of science.
You can view more information about Manya and the StorySmith website.
2002-03
Date and Time: Wednesday, May 28, 2003, 7:00 PM in the Science Center Lecture Hall, with a student poster session and refreshments in the Eldridge Commons.
Prof. Steve Wang
Swarthmore College
"The Good, the Bad, and the Ugly: Principles and Pitfalls of Displaying Data"
Prof. Wang's short talk, including his nomination for the worst graphic ever, is part of our chapter's annual year-end Strawberry Festival.
Date and Time: Monday, November 25, 2002, 8:00 PM in the Kirby Lecture Hall.
Prof. Bjarne Stroustrup
AT&T Labs and Texas A&M University
"Programming, Programming Languages, and Programmers"
Talk Abstract:
Programming seems easy, so why is it sometimes hard? What's hard about writing a program? why? and for whom? This presentation shows a few examples of programming tasks and discusses where the fundamental and practical difficulties lie. Among the topics considered are large systems (what's large?), embedded systems (what are those?), and student projects. My point of view is that of someone who has spent a lot of time seeing industrial and research projects succeed and fail while trying to address some of problems observed through programming language design, library design, tool building, improved techniques, and education. Don't expect simple or complete answers.
You can view the program, including the list of new inductees, for Prof. Stroustrup's talk. Also have a look at his webpage.
Date and Time: Wednesday, October 2, 2002, 8:00 PM in the Scheuer Room, Kohlberg.
Prof. Sonke Johnsen
Duke University, Dept. of Biology
"Hide and Seek in the Open Sea: the Ecology and Physiology of Transparent Organisms"
Talk Abstract:
Prof. Johnsen, Swarthore class of 1988, talked to us about his discovery and analysis of transparent sea creatures. In lieu of a traditional abstract, we posted a poem by John Updike, inspired by Johnsen's work.
View the announcement for Prof. Johnsen's talk. And read about Prof. Johnsen's research on transparent sea creatures in this Scientific American article and view photos on his website.