Optimized Trigger for Ultra-High-Energy Cosmic-Ray and Neutrino Observations with the Low Frequency Radio Array

When an ultra-high energy neutrino or cosmic ray strikes the Lunar surface a radio-frequency pulse is emitted. We plan to use the LOFAR radio telescope to detect these pulses. In this work we propose an efficient trigger implementation for LOFAR optimized for the observation of short radio pulses.Comment: Submitted to Nuclear Instruments and Methods in Physics Research Section

Free Energies and fluctuations for the unitary Brownian motion

We show that the Laplace transforms of traces of words in independent unitary Brownian motions converge towards an analytic function on a non trivial disc. These results allow one to study the asymptotic behavior of Wilson loops under the unitary Yang--Mills measure on the plane with a potential. The limiting objects obtained are shown to be characterized by equations analogue to Schwinger--Dyson's ones, named here after Makeenko and Migdal

Damage Spreading in ±J\pm J Asymmetric Ising Spin Glasses

Spin glasses in dimensions 2, 3, 4 and mean field are studied numerically as a function of the degree of asymmetry of the interactions between spins. Damage spreading data are used to assess the effects on the spin glass ordering of introducing asymmetry in the couplings. In all dimensions the critical temperature for damage spreading is rather insensitive to the asymmetry, but the spin glass ordering is strongly suppressed by any finite degree of asymmetry. We discuss the physical significance of the damage spreading parameter

Natural endocrine profiles of the group-living skunk anemonefish Amphiprion akallopisos in relation to their size-based dominance hierarchy

International audienceGroup-living animals commonly display differences in behaviour, physiology and endocrine profilesbetween conspecifics within the group, which are tightly linked to reproduction. Teleosts exhibit avariety of social systems, where social status, as well as sex, has been linked to different androgenand oestrogen profiles. Levels of gonadal androgen and oestrogen were investigated as a function ofsex and position in a social hierarchy in free-living individuals of the skunk anemonefish Amphiprionakallopisos, a protandrous pomacentrid fish with a size-based dominance hierarchical social system.Plasma levels of 11-ketotestosterone (11-KT), testosterone (T) and 17훽-oestradiol (E 2 ), as well asconversion ratios from T, were measured by ELISA from 111 individuals along a linear hierarchyfrom 38 social groups in the wild. Blood plasma levels of 11-KT and E 2 showed sex differences, beinghigher in males and females respectively as expected based on their role as the major androgen andoestrogen in fish reproduction. However, no sex differences were found for T, which may representits role in territorial defence or simply as a precursor for the synthesis of 11-KT and E 2 . In terms ofthe hierarchical social system within males, 11-KT levels decline as the hierarchy is descended, whichmay represent their decreasing reproductive opportunity, as well as the decreasing levels of aggressiontowards males lower in the hierarchy. In summary, the size-based dominance hierarchy is associatedwith distinct steroid levels of 11-KT and E 2 between individual free-living A. akallopisos that closelyresemble those of species in which breeding individuals suppress reproduction of conspecifics lowerin the hierarchy

The mid-infrared channel of the EChO mission

International audienceThe Exoplanet Characterisation Observatory, EChO, is a dedicated space mission to investigate the physics and chemistry of Exoplanet atmospheres. Using the differential spectroscopy by transit method, it will provide simultaneously a complete spectrum in a wide wavelength range between 0.4mum and 16mum of the atmosphere of exoplanets. It has been selected by ESA in its M3 Cosmic Vision program for a phase A study. The payload is subdivided into 6 channels. The mid-infrared channel covers the spectral range between 5mum and 11mum. In order to optimize the instrument response and the science objectives, the bandpass is split in two using an internal dichroic. We present the opto-mechanical concept of the MWIR channel and the on-going detector development that drives the thermal and mechanical designs of the channel. The estimated end-to-end performance will also be presented

The mid-infrared channel of the EChO mission

International audienceThe Exoplanet Characterisation Observatory, EChO, is a dedicated space mission to investigate the physics and chemistry of Exoplanet atmospheres. Using the differential spectroscopy by transit method, it will provide simultaneously a complete spectrum in a wide wavelength range between 0.4mum and 16mum of the atmosphere of exoplanets. It has been selected by ESA in its M3 Cosmic Vision program for a phase A study. The payload is subdivided into 6 channels. The mid-infrared channel covers the spectral range between 5mum and 11mum. In order to optimize the instrument response and the science objectives, the bandpass is split in two using an internal dichroic. We present the opto-mechanical concept of the MWIR channel and the on-going detector development that drives the thermal and mechanical designs of the channel. The estimated end-to-end performance will also be presented

Laser-induced breakdown spectroscopy acoustic testing of the Mars 2020 microphone

The SuperCam instrument suite onboard the Mars 2020 rover will include the Mars Microphone, an experiment designed to record the sounds of the SuperCam laser strikes on rocks and also aeolian noise. In order to record shock waves produced by the laser blasts, the Mars Microphone must be able to record audio signals from 100 Hz to 10 kHz on the surface of Mars, with a sensitivity sufficient to monitor a laser impact at distances up to 4 m. The Aarhus planetary simulator facility has been used to test the Mars 2020 rover microphone in a controlled Martian environment. The end-to-end tests performed in a 6 mbar CO2 atmosphere, with wind, and also with the microphone at −80° C have demonstrated that the SuperCam/Mars Microphone requirements are satisfied. Tests were also performed on Martian soil simulant targets showing that the variation of the acoustic energy of the shock wave depends on the level of compaction of the target