Marmots do not consistently use their left eye to respond to an approaching threat but those that did fled sooner.

In many vertebrates, the brain's right hemisphere which is connected to the left visual field specializes in the processing of information about threats while the left hemisphere which is connected to the right visual field specializes in the processing of information about conspecifics. This is referred to as hemispheric lateralization. But individuals that are too predictable in their response to predators could have reduced survival and we may expect selection for somewhat unpredictable responses. We studied hemispheric lateralization in yellow-bellied marmots Marmota flaviventer, a social rodent that falls prey to a variety of terrestrial and aerial predators. We first asked if they have lateralized responses to a predatory threat. We then asked if the eye that they used to assess risk influenced their perceptions of risk. We recorded the direction marmots were initially looking and then walked toward them until they fled. We recorded the distance that they responded to our experimental approach by looking, the eye with which they looked at us, and the distance at which they fled (i.e., flight initiation distance; FID). We found that marmots had no eye preference with which they looked at an approaching threat. Furthermore, the population was not comprised of individuals that responded in consistent ways. However, we found that marmots that looked at the approaching person with their left eye had larger FIDs suggesting that risk assessment was influenced by the eye used to monitor the threat. These findings are consistent with selection to make prey less predictable for their predators, despite underlying lateralization

A mid-IR study of Hickson Compact Groups II. Multi-wavelength analysis of the complete GALEX-Spitzer Sample

We present a comprehensive study on the impact of the environment of compact galaxy groups on the evolution of their members using a multi-wavelength analysis, from the UV to the infrared, for a sample of 32 Hickson compact groups (HCGs) containing 135 galaxies. Fitting the SEDs of all galaxies with the state-of-the-art model of da Cunha (2008) we can accurately calculate their mass, SFR, and extinction, as well as estimate their infrared luminosity and dust content. We compare our findings with samples of field galaxies, early-stage interacting pairs, and cluster galaxies with similar data. We find that classifying the groups as dynamically "old" or "young", depending on whether or not at least one quarter of their members are early-type systems, is physical and consistent with past classifications of HCGs based on their atomic gas content. [...ABRIDGED...] We also examine their SF properties, UV-optical and mid-IR colors, and we conclude that all the evidence point to an evolutionary scenario in which the effects of the group environment and the properties of the galaxy members are not instantaneous. Early on, the influence of close companions to group galaxies is similar to the one of galaxy pairs in the field. However, as the time progresses, the effects of tidal torques and minor merging, shape the morphology and star formation history of the group galaxies, leading to an increase of the fraction of early-type members and a rapid built up of the stellar mass in the remaining late-type galaxies.Comment: Accepted for publication in A&A. Figure resolution degraded for arXiv limits, full resolution paper available at http://www.physics.uoc.gr/~bitsakis/paperII_bitsakis.pd

Disentangling the dynamical origin of P11 Nucleon Resonances

We show that two almost degenerate poles near the $\pi\Delta$ threshold and the next higher mass pole in the $P_{11}$ partial wave of $\pi N$ scattering evolve from a single bare state through its coupling with $\pi N$, $\eta N$ and $\pi\pi N$ reaction channels. This finding provides new information on understanding the dynamical origins of the Roper $N^*(1440)$ and $N^*(1710)$ resonances listed by Particle Data Group. Our results for the resonance poles in other $\pi N$ partial waves are also presented.Comment: Improved version, accepted Phys. Rev. Let

Nuclear gas core propulsion research program

Viewgraphs on the nuclear gas core propulsion research program are presented. The objectives of this research are to develop models and experiments, systems, and fuel elements for advanced nuclear thermal propulsion rockets. The fuel elements under investigation are suitable for gas/vapor and multiphase fuel reactors. Topics covered include advanced nuclear propulsion studies, nuclear vapor thermal rocket (NVTR) studies, and ultrahigh temperature nuclear fuels and materials studies

Coupled channel study of K+ΛK^+\Lambda photoproduction

A coupled channel model with $\gamma N$, $KY$ and $\pi N$ channels has been used to analyze the recent data of $\gamma p \to K^+ \Lambda$. The non-resonant interactions within the subspace $KY \oplus \pi N$ are derived from effective Lagrangians using a unitary transformation method. The direct photoproduction reaction is obtained from a chiral constituent quark model with $SU(6)\otimes O(3)$ breaking. Missing baryon resonances issues are briefly discussed.Comment: Part of the proceedings of the International Workshop on the Physics of Excited Baryons NSTAR05, 12-15 October 2005, Tallahassee, Florida, US