Snow and Thunder

William Apel, professor of religion, shares his thoughts and observations about the Global Baptist Peace Conference he attended in Rome

Test of hadronic interaction models with air shower data

The description of high-energy hadronic interactions plays an important role in the (astrophysical) interpretation of air shower data. The parameter space important for the development of air showers (energy and kinematical range) extends well beyond todays accelerator capabilities. Therefore, accurate measurements of air showers are used to constrain modern models to describe high-energy hadronic interactions. The results obtained are complementary to information gained at accelerators and add to our understanding of high-energy hadronic interactions.Comment: Invited talk at the 13th International Conference on Elastic & Diffractive Scattering, CERN, 200

Exploring January Term

An inside look at three courses offered on the McMinnville Campus during January Term: Monks and Mystics, Scriptwriting, and Physics of Art and Music

The aerocrew mission : training space Session at Ny Aalesund Arctic base

The Aerocrew mission has been realized in December 2007, in the frame of the International Polar Year, and in cooperation with the Polar Institut Paul-Émile Victor. The team has realized an original5 days training experience at Ny-Aalesund Arctic Base (79°N) the. The 11 crew members constituted a space crew, including physicians, aerospace crew trainers and engineers, and were implied in a seminar with 4 sessions, dealing with the training capabilities of Arctic Bases. The goal was on one hand to show that this kind of base constitutes a pertinent and affordable facility for space and aerospace teams, and on the other hand that the specific aerospace crew training techniques, could be fruitful for the scientists in artcic bases (glaciologists, geologists, specialists of the atmosphere). The 4 sessions, given by professionals of aerospace, robotics and medicine, covered the training methods for crews, robotics for outdoor and indoor activities, engineering of embedded systems, and the internal arrangement of crafts. The experience has shown the efficiency of a transverse visiting multidisciplinary team for training, and possible synergies with the resident scientists. In addition, the sessions were enriched by demonstrations such as mini-robot for observation, micro-helicopter for special sites, and also the comparison between EVA Russian glove and Polar Suits. After this mission, it was possible to conclude that this kind of cooperation could certainly open perspectives with crossed benefits either for space training and arctic research

Landau level splitting due to graphene superlattices

The Landau level spectrum of graphene superlattices is studied using a tight-binding approach. We consider non-interacting particles moving on a hexagonal lattice with an additional one-dimensional superlattice made up of periodic square potential barriers, which are oriented along the zig-zag or along the arm-chair directions of graphene. In the presence of a perpendicular magnetic field, such systems can be described by a set of one-dimensional tight-binding equations, the Harper equations. The qualitative behavior of the energy spectrum with respect to the strength of the superlattice potential depends on the relation between the superlattice period and the magnetic length. When the potential barriers are oriented along the arm-chair direction of graphene, we find for strong magnetic fields that the zeroth Landau level of graphene splits into two well separated sublevels, if the width of the barriers is smaller than the magnetic length. In this situation, which persists even in the presence of disorder, a plateau with zero Hall conductivity can be observed around the Dirac point. This Landau level splitting is a true lattice effect that cannot be obtained from the generally used continuum Dirac-fermion model.Comment: 12 pages, 9 figure