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New Faculty in the Eberly College of Science

Stephon Alexander, assistant professor of physics

Stephon Alexander has research interests that include investigations at the interface between cosmology and such fundamental areas of physics as string theory—which attempts to merge quantum mechanics with Albert Einstein’s general theory of relativity as a description of fundamental physics—and quantum gravity—which attempts to merge two theories that describe the four fundamental forces of nature into a unified “theory of everything.” He also is working on ways to use gravitational waves to probe the connection between inflationary theory—which describes the epoch in the universes’ past when it rapidly expanded from a microscopic size to the size that we observe today—and the origin of matter in the universe. Alexander’s research also includes efforts to use quantum gravity in order to understanding the cosmological constant—also known as dark energy.

In 2006, Alexander was named one of eight National Geographic Emerging Explorers. His work also has been recognized with a Particle Physics and Astronomy Research Council (PPARC) postdoctoral fellowship in 2000, a Graduate Assistance in Areas of National Need (GANN) Fellowship in 1998, and a National Aeronautics and Space Administration (NASA) fellowship in 1997. He was selected as a New England Board of Higher Education Scholar in 1994, and won a Hansiker Award from Haverford College Department of Mathematics in 1990.

In addition to his published scientific papers, Alexander has presented invited talks at universities and institutes across the United States and in Canada, Switzerland, the United Kingdom, Greece, Jamaica, and Brazil. He also has participated in scientific conferences and workshops in Brazil, France, Germany, Greece, Italy, Morocco, the U.K., and the U.S.

Prior to joining Penn State during the fall semester of 2005, Alexander was a postdoctoral researcher at Stanford University from 2002 to 2005. He had been a postdoctoral researcher at Imperial College in the United Kingdom from 2000 to 2002 and was a visiting postdoctoral researcher at Columbia University from 2001 to 2002. He also conducted research in structural biophysics at Harvard University from 1994 to 1995.

Alexander earned his bachelor’s degree in physics at Haverford College in 1993. At Brown University, he earned master’s degrees in physics in 1995, a master’s degree in electrical engineering in 1996, and a doctoral degree in physics in 2000.

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John Asbury, assistant professor of chemistry

John Asbury studies the chemical and structural changes associated with degradation of such emerging solid-state, electro-active materials as organic photovoltaics used to generate solar power; organic diodes used in energy-efficient lighting; organic dielectrics used in artificial muscles; and organic semiconductors used in disposable, electronic, anti-theft tags in consumer electronics.

Scientists have identified state-of-the-art materials that perform well and can be made economically in high volumes, but they quickly degrade. “There are viable candidates selected for the next-generation materials for each application, but each one has too short of an operational lifetime,” explains Asbury.

Asbury’s research focus is to identify the chemical reactions that lead to degradation of those materials. He uses ultra-fast, multidimensional, infrared-vibrational spectroscopy to resolve the duration of chemical reactions and identify the molecular structures involved in the reactions that lead to the breakdown of the material.

The Femtosecond lasers that Asbury uses in his research operate at time scales of less than a millionth of a millionth of a second. With this time resolution, Asbury’s group is able to capture molecules in the act of reacting in order to understand how to develop new materials that are less susceptible to degradation. The long-range goal of Asbury’s research is to explore the nature of chemical reactions in solid-state materials, and to learn how the quasi-rigid environment of solids affects the progress of reactions in contrast to similar processes in liquids.

Asbury was awarded the Camille and Henry Dreyfus New Faculty Award in 2005. He received an Achievement Rewards for College Scientists Scholar Award for excellence in graduate studies in 2000 and 2001 and an Osborne R. Quayle Fellowship for excellence in graduate studies in 1999. He has authored or co-authored over forty research papers in scientific journals.

Prior to joining Penn State in 2005, Asbury was a postdoctoral fellow at Stanford University from 2001 to 2005. He received a bachelor’s degree from the University of Tennessee in 1996, graduating at the top of the chemistry class, and was named the Hoeschst-Celanese Best Junior Chemistry Major in 1995. He received his doctoral degree from Emory University in 2001.

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Martin Bojowald, assistant professor of physics

Martin Bojowald studies quantum gravity and cosmology, using a loop-quantization approach developed primarily at Penn State. His research in loop quantum cosmology has suggested several candidates for observations of indirect effects of quantum gravity. He focuses on developing detailed calculational tools for comparing predictions with collected data, such as that anticipated from the Planck satellite expected to be launched in 2007 by the European Space Agency. “Cosmological models give insights into our understanding of the nature of space-time on small scales,” explains Bojowald. “Loop quantum cosmology allows us to develop well-defined models of the emergence of our universe, again revealing possible observable implications.”

Martin also is interested in areas of mathematical physics, such as the theory of effective equations, dynamical coherent states for quantum systems, field theory, and Poisson geometry and its applications in gravity.

Bojowald received first prize in the Gravity Research Foundation’s Essay Competition in 2003. In addition to his published scientific papers, he has presented invited talks at universities and institutions in Austria, France, Germany, India, Mexico, The Netherlands, Poland, South Africa, Switzerland, the United Kingdom, and the United States.

Bojowald has served on the editorial board for General Relativity and Gravitation since January 2006. He was a member of the board for the Gravity Section of the German Physical Society from 2004 to 2006. He was on the local organization committee for the Annual International Meeting on Non-Perturbative/Background-Independent Quantum Gravity in Potsdam, Germany, in 2005 and is co-organizing a workshop that will take place at the Kavli Institute for Theoretical Physics at the University of California at Santa Barbara in January 2007.

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Derek Fox, associate professor of astronomy and astrophysics

Derek B. Fox studies the physics of gamma-ray-burst explosions, the nature of short-duration gamma-ray bursts, and the application of gamma-ray-burst afterglows to the understanding of problems in galaxy formation and cosmology. He also is interested in using white-dwarf stars, neutron stars, and black holes as physical laboratories. He studies multiwavelength follow-up observations of gamma-ray bursts in collaboration with the Swift Satellite Team at Penn State.

In his first year at Penn State, Fox led a team that solved the 35-year-old mystery of the origin of powerful, split-second flashes of light known as short-duration gamma-ray bursts by tracing the location of one such burst to a blue dwarf galaxy two billion light-years from Earth and by observing its fading afterglow for almost a month with the Hubble Space Telescope. He later coauthored a paper making use of these results to calculate, for the first time, the expected rate of gravity-wave detections from short bursts for the newly-operational Laser Interferometer Gravitational-Wave Observatory.

In his previous work, Fox adapted the Oschin 48-inch and Oscar Meyer 60-inch telescopes at the Palomar Observatory in order to make rapid-response observations of gamma-ray bursts and used these telescopes to discover three very “young” burst afterglows. By moving quickly to observe and analyze the data from these and other facilities, Fox discovered the afterglows of more than a dozen gamma-ray bursts and, with colleagues at the California Institute of Technology, found the first three afterglows of X-ray Flashes and also made the first measurements of the distance to an X-ray Flash.
Fox has published several scientific papers about his research. He was a panelist in 2003 and 2005 for NASA press conferences that resulted from his research articles published in the
journal Nature.

Fox is a member of the American Astronomical Society, the American Physical Society, and the scientific research society Sigma Xi. Prior to joining Penn State for the fall semester of 2005, Fox was a postdoctoral scholar and project scientist at the California Institute of Technology from 2001 to 2005. At the Massachusetts Institute of Technology, he held a National Science Foundation Graduate Fellowship from 1993 to 1996 and a Karl Taylor Compton Fellowship from 1993 to 1995. He earned his doctoral degree in physics at the Massachusetts Institute of Technology in 2000 and earned his bachelor’s degree in physics at Princeton University in 1993.

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John Fricks, assistant professor of statistics

John Fricks is
interested in stochastic processes, including numerical methods and statistical inference, especially involving stochastic models in molecular biology, including molecular motors such as dynein and kinesin. These motors convert chemical energy into physical forces at the subcellular level, enabling a number of important biological processes.

One focus of his research has been to rigorously define and mathematically explore certain types of these models proposed by biologists and biophysicists, especially the Brownian ratchet. The Brownian ratchet model describes the movement of molecular-scale particles that can pass freely through barriers in one direction and are stopped from passing through from the other direction.

Another focus of his research is the development of efficient numerical methods that can provide qualitative comparisons between stochastic models and the observed behavior of biological systems. He also has been developing statistical methods to allow a quantitative link between abstract models and new types of data being collected by experimentalists.

Fricks is a member of the Institute of Mathematical Statistics, the Society for Industrial and Applied Mathematics (SIAM), and the Society for Mathematical Biology. His research accomplishments have been recognized with a National Science Foundation Mathematical Sciences Postdoctoral Fellowship in 2004 and a Kenan Fellowship from the University of North Carolina in 1999.

In addition to publishing research papers in scientific journals, he has participated in scientific conferences including the SIAM Annual Meeting in 2005 and the Society for Mathematical Biology Annual Meeting in Scotland in 2003, and has given presentations at several workshops.

Prior to joining Penn State in the fall semester of 2005, Fricks was at the University of North Carolina as a research assistant professor of mathematics from 2004 to 2005 and as a research assistant and teaching assistant between 2000 to 2004. He was an instructor at Hopkinsville Community College in 1999 and was a teaching assistant at Western Kentucky University between 1996 and 1999.

Fricks earned his bachelor’s degree in economics and music performance, specilizing in classical guitar, at Western Kentucky University in 1994. He pursued post-baccalaureate studies in mathematics at the University of Louisville in 1994 and 1995 and in computer science at Indiana University in 1995. He earned a master’s degree in mathematics at Western Kentucky University in 1999. At the University of North Carolina, he earned master’s and doctoral degrees in statistics in 2003 and 2004, respectively.

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Helge Kristian Jenssen, assistant professor of mathematics

Helge K. Jenssen is a mathematician who studies the properties of nonlinear partial differential equations, a research area of fundamental importance in modern pure and applied mathematics. His research focuses on equations that describe evolutionary processes, such as wave propagation and fluid flow. His studies of these evolutionary equations include questions about the existence, uniqueness, and qualitative properties of solutions. Of particular interest to Jenssen are equations describing gas dynamics and combustion phenomena.

Jenssen’s research accomplishments have been recognized with a Career award from the National Science Foundation in 2005 and with an ESSO Award for the Best Doctoral Thesis in Fundamental Research from the Norwegian University of Science and Technology in 1998. He is a member of the Society for Industrial and Applied Mathematics (SIAM) and the American Mathematical Society.

Jenssen has scientific papers in several scientific journals and six articles in refereed proceedings and reports. He has served as a reviewer for Mathematical Reviews since 2005, and has been a reviewer of proposals for the U.S. Civilian Research and Development Foundation since June of 2006. He has been a referee for several scientific journals, including AMS Contemporary Mathematics, the Archive for Rational Mechanics and Analysis, Computers and Fluids, the Journal of Computational and Applied Mathematics, the Journal of Hyperbolic Differential Equations, the Journal of Mathematical Analysis and Applications, the SIAM Journal of Mathematical Analysis, the SIAM Journal of Applied Mathematics, and Transactions of the American Mathematical Society.

He has presented invited talks at professional conferences such as the SIAM Conference on Analysis of Partial Differential Equations in 2006 and the American Institute of Mathematical Sciences International Conference on Dynamical Systems, Differential Equations, and Applications in 2004 and 2006. He was chair of a session on “Initial Boundary Value Problems” at the 11th International Conference on Hyperbolic Problems in France in 2006. He co-organized a workshop on “Recent Advances in Nonlinear Partial Differential Equations” at the University of Oslo in Norway. He also co-organized three mini symposia at the SIAM Conference on Analysis of Partial Differential Equations in Houston, Texas, in 2004.

Prior to joining Penn State during the fall semester of 2005, Jenssen was an assistant professor of mathematics at North Carolina State University from 2003 to 2005. He was the Zorn Visiting Assistant Professor of Mathematics at Indiana University from 2000 to 2003. He also had been a postdoctoral researcher at the International School for Advanced Studies (SISSA) in Italy from 1998 to 2000. He held visiting professorships at the Mittag-Leffler Institute in Sweden in 1997 and 2005 and at the International School for Advanced Studies in Trieste, Italy, at various times between 1998 and 2003. From 1994 to 1995, he served in the Norwegian military in the Department of Underwater Acoustics at the Norwegian Defense Research Establishment.

Jenssen earned his master’s degreein mathematics at the University of Oslo, Norway, in 1994 and earned his doctoral degree in mathematics at the Norwegian University of Science and Technology in 1998.

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Andrey Krasilnikov, assistant professor of biochemistry and molecular biology

Andrey Krasilnikov studies the spatial organization of highly structured RNA molecules and the complexes of such molecules with RNA-binding proteins. Krasilnikov uses X-ray crystallography to achieve an atomic-resolution level of detail. “Using a combination of crystallographic and biochemical studies we can answer a very broad variety of fundamental questions,” explains Krasilnikov. “Questions range from the mechanisms of substrate recognition and catalysis to the structural and functional roles of individual parts of the molecule or complex.”

Despite the fact that only four basic building blocks make up RNA molecules, RNA is a very flexible molecule that can form intricate networks of various intramolecular interactions, explains Krasilnikov. This flexibility allows RNA to fold into complicated, three-dimensional structures and to play advanced roles, including substrate recognition and catalysis. “RNA used to be considered a simple disposable copy of DNA serving as a template to make proteins,” says Krasilnikov. “However, recent discoveries show that highly structured RNA molecules play a crucial role in regulation of gene expression and are capable of catalyzing chemical reactions, just like the proteins do.”

Krasilnikov’s lab is particularly interested in several key RNA molecules and RNA-protein complexes including Ribonuclease MRP, an ubiquitous enzyme found in eukaryotic, or nucleus-containing, cells consisting of a large RNA component and several proteins. Ribonuclease MRP plays a role in DNA replication in mitochondria, maturation of ribosomal RNA, and regulation of the cell cycle in yeast. In humans, some mutations of Ribonuclease MRP can cause a form of short-limbed dwarfism causing abnormal skeletal growth and Cartilage-Hair Hypoplasia, also known as McKusick-type metaphyseal chondrodysplasia, a rare syndrome affecting the immune system.

This year, Krasilnikov received a Beckman Young Investigator Award, which recognizes the most promising young faculty members in chemical and life sciences. He was awarded a National Research Service Award for his research from 2002-2004 by the National Institutes of Health.
Krasilnikov is a reviewer for scientific journals such as Nucleic Acids Research, RNA, and Biochemistry. He presented his study on crystal structures of bacterial Rribonuclease P in 2004 at the Ninth Annual International Meeting of the RNA Society. He has presented seven other invited talks about his research since 2004 and has published several research papers in scientific journals.

Prior to joining Penn State in 2005, Krasilnikov was a postdoctoral fellow in Biochemistry, Molecular Biology, and Cell Biology at Northwestern University from 2000 to 2005. He was a postdoctoral fellow in Molecular Genetics at the University of Illinois at Chicago from 1996 to 1999 and a scientist at the Institute of Molecular Genetics at the Russian Academy of Sciences from 1995 to 1996.

Krasilnikov received his master’s degree in physics, cum laude, from the Moscow Institute of Physics and Technology in 1991. He received his doctoral degree in 1995 from the Institute of Chemical Physics at the Russian Academy of Sciences.

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Xiantao Li, assistant professor of mathematics

Xiantao Li has focused his research program on the modeling of crystalline materials, which are solids whose structure consists of a repeating pattern of atoms, ions, or molecules. Li’s research involves modeling these materials at a variety of length scales. The principal objectives of his research are to extract the properties of materials from models of their atomic structure; to understand the energetics and dynamics of defects in the structure of materials; to design novel methods to model the behavior of materials across different scales; and to develop effective continuum models, which are used widely in a variety of engineering applications.

Li’s research accomplishments have been recognized with a John Nohel Prize from the University of Wisconsin-Madison in 2001 and a travel award from the Society for Industrial and Applied Mathematics (SIAM) in 2002. He also has published several papers in scientific journals.

Prior to joining Penn State in the fall semester of 2005, Li was a postdoctoral fellow at the University of Minnesota from 2004 to 2005 and was a research associate at Princeton University from 2002 to 2004. He had been a teaching assistant at the University of Wisconsin-Madison from 2000 to 2002 and at the Georgia Institute of Technology from 1998 to 2000.

Li earned his bachelor’s degree in mathematics at Peking University in Beijing, China, in 1998. He earned his doctoral degree in mathematics at the University of Wisconsin-Madison in 2002.

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Aimin Liu, assistant professor of biology

Aimin Liu studies the role of cilia during signal transduction and mammalian embryonic development. His work explores the relationship between a group of proteins instrumental to the formation of cilia and to Hedgehog signaling, two processes that are essential to the early development of many vertebrate organisms.

Liu’s recent research indicates these proteins, called intraflagellar transport proteins, play a critical role in the development of mouse embryos and in the regulation of Hedgehog signaling. Cilia are microtubule-based organelles found on the surface of nearly all types of cells in animals. Cells rely on cilia to sense stimuli like motion, light, hormones, and odor. Disruption of cilia function is responsible for many human birth defects.

Liu’s lab focuses, in particular, on the relationship between the intraflagellar transport proteins and the two Hedgehog-signaling pathway components: Sufu and Gli. He also examines the relationship between cilia formation, cell-skeleton organization, and cell polarity. Liu’s lab recently discovered that a chemically induced mouse mutant with extra digits in its limbs has a mutation that replaces one amino acid with another in a protein involved in cell polarity and cell-skeleton organization.

Liu received a National Research Service Award in 2004-2005 to support his analysis of Flexo, a novel regulator of Hedgehog signaling. In 1999, he received prizes for poster-presentations of his research at scientific meetings: one at the Society for Developmental Biology annual meeting; one at the SDB Northeast regional annual meeting; and one, the Lennart Philipson Poster Prize, at the Skirball Institute Annual Retreat. The Beijing Society for Genetics honored Liu in 1992 with the Outstanding Research Article by a Young Scientist Award. Liu has authored or co-authored a number of research papers published in scientific journals.

Prior to joining Penn State in 2006, Liu was a postdoctorate fellow from 2004 to 2005 at the University of Colorado Health Sciences Center. He was a research fellow at the Howard Hughes Medical Institute and Memorial Sloan-Kettering Cancer Center in New York from 2001 to 2004, and was a lecturer at Peking University in Beijing from 1994 to 1995. Liu received his bachelor’s and master’s degrees in biology from Beijing University in 1989 and 1992, respectively, and his doctoral degree in 2000 from New York University’s School of Medicine.

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Kevin Luhman, associate professor of astronomy and astrophysics

Kevin L. Luhman studies the formation of stars, brown dwarfs, and planets through optical and infrared observations with ground-based and space-based telescopes, including the Keck Observatory in Hawaii, the Gemini Observatories in Hawaii and Chile, the Magellan Telescopes in Chile, the Hubble Space Telescope, the Spitzer Space Telescope, and Penn State’s Hobby-Eberly Telescope in Texas. One of his primary projects has involved measuring the number of low-mass stars and brown dwarfs as a function of mass to test a wide range of theories about their formation. Through deep photometric and spectroscopic surveys of nearby star-forming regions, he has searched for brown dwarfs down to masses of 0.01 solar masses (about 10 Jupiter masses) and has compared the resulting data to predictions made by theoretical models for the formation of stars and brown dwarfs. To continue to test these theories more critically, he hopes to extend his measurements down to the mass of Jupiter in order to determine the lowest mass at which star-like bodies can form.

Luhman recently has begun a long-term program to characterize the process of planet formation around low-mass stars and brown dwarfs by using current observatories, as well as observatories expected to be in service in the near future. In an early result from this work, he and his collaborators have used the Spitzer Infrared-Array Camera to discover the two least-massive brown dwarfs known to have circumstellar disks. The presence of disks around these extremely low-mass objects (8 and 15 Jupiter masses) demonstrates that the formation of free-floating bodies via disks extends down to planetary masses and raises the possibility of planet formation around objects that themselves have planetary-scale masses.

Luhman’s research accomplishments were recognized in 2006 with a Faculty Early Career Development Award from the National Science Foundation. He is a member of the American Astronomical Society and has published 50 scientific papers about his research. He has served on the NASA origins of the Solar System Review Panel from 2000 to 2002, the NASA IRTF Telescope Allocation Committee from 2001 to 2004, the NASA Hubble Space Telescope Review Panel in 2005, the NASA Spitzer Space Telescope Review Panel in 2005, the NOAO Telescope Allocation Committee in 2005, the NSF Division of Astronomical Sciences Review Panel in 2006, and the NSF AURA Management Review Panel in 2006.

Prior to joining Penn State in 2005, Luhman worked at the Harvard-Smithsonian Center for Astrophysics as an astrophysicist from 2002 to 2005 and as a postdoctoral fellow from 1998 to 2002. While completing his doctoral studies at the University of Arizona, he also was a teaching and research assistant.

Luhman earned bachelor’s degrees in in astronomy and physics at the University of Texas in 1993 and attended the Vatican Observatory Summer School in Castel Gandolfo, Italy, that summer. He earned a doctoral degree in astronomy at the University of Arizona in 1998.

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Kathleen Postle, professor of biochemistry and molecular biology

Kathleen Postle uses the bacterium Escherichia coli as a model system to learn how signals are transduced between the two concentric membranes surrounding Gram-negative bacteria, many species of which can cause disease. Postle studies the mechanism by which a protein called TonB delivers energy to transporters in the bacterium’s outer membrane, triggering delivery of essential iron to the bacteria. Understanding this mechanism may lead to development of new, effective treatments for the diseases these bacteria cause. During a bacterial infection, Gram-negative bacteria can feed off iron in the human body. If unable to get iron, they cannot grow and reproduce.

“The TonB system presents an attractive target for development of novel antibiotics that could interfere with bacterial iron nutrition,” explains Postle. “Understanding the molecular mechanism of TonB-dependent energy transduction also will provide unique and important insights into the signal-transduction processes, in general.”

Postle has delivered many invited talks to academic researchers, including three addresses at national meetings of the American Society of Microbiology, and has presented papers or posters at a number of conferences. She also has published a number of scientific papers about her research, which has been funded by the National Institutes of Health and the National Science Foundation.

Postle served on grant-review panels for the National Science Foundation for Cell Biology from 1990 to 1997, and for the National Institute of Health for microbial physiology from 1998 to 2001. She has served on the editorial board of the Journal of Bacteriology since 1998.

The National Science Foundation honored Postle in 1991 with a Career Advancement Award for Women. She also was awarded an American Society for Microbiology Foundation Lectureship from 1991 to 1992.

Prior to joining Penn State in 2005, Postle was a professor in the School of Molecular Biosciences at Washington State University from 1994 to 2005. She was an associate professor at Washington State from 1986 to 1994, and an assistant research professor at the University of California at Irvine from 1982 to 1986. From 1978 to 1981, she was a postdoctoral fellow at the University of Washington and the University of California at Irvine, respectively.

Postle received her bachelor’s degree in chemistry, magna cum laude, from Wittenberg University in Springfield, Ohio, in 1972, where she was recognized as Outstanding Senior Chemistry Major, and received her doctoral degree in biochemistry from the University of Wisconsin-Madison in 1978.

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Paul Sommers, professor of physics

Paul Sommers has been an active participant in the design and construction of the Pierre Auger Cosmic Observatory, an array of cosmic-ray detectors located in a remote part of Argentina. The Auger Observatory was built to decipher the messages carried by the highest-energy cosmic rays. The messages arrive as particles from space with energies 100 million times greater than can be achieved on Earth, even in the best superconducting particle accelerators. These ultrahigh-energy cosmic rays offer a new window for observing extreme processes at work in the universe. Sommers is the co-chair of the Auger Collaboration Board.

The Auger Observatory detectors are spread across a large area, the size of Rhode Island, because the highest-energy rays are very rare. Several detections per year are expected over the observatory’s 1200 square miles. Each energetic particle interacts with an atomic nucleus high in our atmosphere and produces roughly 100 secondary energetic particles. Each secondary particle collides and produces additional particles. This cascade grows until billions of secondary particles are spread over several square miles at ground level. The Auger Observatory samples the density of those secondary particles using 1600 water particle detectors that are deployed in a regular array over the Argentine pampa. The recorded signal amplitudes and arrival times allow researchers to determine the energy and the arrival direction of the ultrahigh-energy cosmic ray.

Sommers was an early advocate of combining air-fluorescence detectors with the giant surface-detector array. He led the team that developed the fluorescence detectors during the design and prototype phases of the observatory.

The Auger Observatory is an international collaboration of 16 partner countries. The site in Argentina is expected to be completed near the end of 2006, and a northern-hemisphere site in Colorado is planned to provide exposure to sources that lie in the northern half of the sky. “We are opening new windows to the universe that complement traditional astronomy,” says Sommers. “The Auger Observatory, the IceCube neutrino detector, and the Laser Interferometer Gravitational Wave Observatory (LIGO) are now poised to make important astrophysical observations.”

He is a member of the American Physical Society and an associate member of the Kavli Institute for Cosmological Physics. In addition to publishing several papers in scientific journals, he has made presentations at several professional conferences. He also has authored or co-authored many technical notes for the Pierre Auger Observatory.

Prior to joining Penn State during the summer of 2005, Sommers was at the University of Utah where he was a research professor of physics from 1993 to 2005 and a scientific research staff specialist from 1982 to 1992. He was an assistant professor of mathematics at North Carolina State University from 1977 to 1980, and was the Bahnson Postdoctoral Research Fellow at the University of North Carolina from 1975 to 1977. He also was a NATO postdoctoral fellow at Oxford University from 1973 to 1975.

Sommers earned a bachelor’s degree in physics at the University of California at Berkeley in 1968 and a master’s degree in physics at the University of California at San Diego in 1969. He earned a doctoral degree in relativity at the University of Texas in 1973.

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Yanming Wang, assistant professor of biochemistry and molecular biology

Yanming Wang conducts research on the molecular mechanisms within a cell that control the function of chromatin, the material in the nucleus that forms chromosomes and contains genes. These mechanisms control the cell’s growth, proliferation and differentiation as well as the maintenace of stem cells. The overproliferation of stem cells or the failure of cell differentiation can produce a large amount of undifferentiated cells, leading to cancer, while balanced stem-cell differentiation and division keeps a break on the development of tumors. Wang’s research concerning these processes has the potential to benefit human health.

Wang recently received the Johnson & Johnson/Penn State Innovative Technology Research Seed Grant to support his research in studying the role of the PAD4 enzyme in cell differentiation and cancer. He has published a number of research papers in prestigious scientific journals and has given invited seminars and presentations at scientific meetings and at other research universities.

Prior to joining Penn State in 2005, Wang was a postdoctoral research associate at Rockefeller University from 2003 to 2005 and a postdoctoral research associate at the University of Virginia from 2001 to 2003.

Wang received his bachelor’s degree in Biochemistry from Shan-Dong University in China in 1994, his master’s degree diploma in Developmental Biology from the Chinese Academy of Science in 1997, and his doctoral degree in Molecular, Cellular, and Developmental Biology from Iowa State University in 2001.

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Jun Zhu, assistant professor of physics

Jun Zhu is leading investigations into the electronic properties of solid-state materials that are so small they are measured in nanometers. Among the materials of particular interest to Zhu is a new two-dimensional electron system in a sheet of bonded carbon atoms known as graphene, which physicists speculate could be used to build new kinds of nanosensors and nanocircuits. Graphene’s unusual electronic properties also are of fundamental interest to physicists, including Zhu, as a possible route to the discovery of new physical phenomena. Zhu also is interested in exploring the behavior of electrons in one-dimensional systems such as carbon nanotubes. Her research methods include the use of atomic-force microscopes and resistivity measurements at very low temperatures.

Zhu is a member of the American Physical Society. In addition to her published scientific papers, she has presented invited talks at universities and institutions in Canada, Italy, and across the United States, and has participated in scientific conferences, including the 15th International Conference on Electronic Properties of Two-Dimensional Systems in 2003 and the 13th International Conference on Scanning Tunneling Microscopy/Spectroscopy and Related Techniques in 2005, both held in Japan.

Prior to joining Penn State in January 2006, Zhu was a postdoctoral scientist at Cornell University from 2003 to 2005. She received her bachelor’s degree in physics from the University of Science and Technology of China in 1996. She later studied in the United States at Columbia University, where she received a master’s degree in physics in 1999 and a doctoral degree in physics in 2003.

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