Many insects exploit skylight polarization for visual compass orientation or course control. As found in crickets, the peripheral visual system (optic lobe) contains three types of polarization-sensitive neurons (POL neurons), which are tuned to different (about 60° diverging) e-vector orientations. Thus, each e-vector orientation elicits a specific combination of activities among the POL neuro...

The magnetic compass sense of animals is currently thought to be based on light-dependent processes like the proposed radical pair mechanism. In accordance, many animals show orientation responses that depend on light. However, the orientation responses depend on the wavelength and irradiance of monochromatic light in rather complex ways that cannot be explained directly by the radical pair mec...

By directional training, young domestic chickens have been shown to use a magnetic compass; the same method has now been used to analyse the functional characteristics and the physical principles underlying the chickens' magnetic compass. Tests in magnetic fields with different intensities revealed a functional window around the intensity of the local geomagnetic field, with this window extendi...

Recent research has focused on the different types of compass cues available to ball-rolling beetles for orientation, but little is known about the relative precision of each of these cues and how they interact. In this study, we find that the absolute orientation error of the celestial compass of the day-active dung beetle Scarabaeus lamarcki doubles from 16° at solar elevations below 60° to a...

Recently we proposed a novel method of alignment-alignment comparison, COMPASS (the tool for COmparison of Multiple Protein Alignments with Assessment of Statistical Significance). Here we present several examples of the relations between PFAM protein families that were detected by COMPASS and that lead to the predictions of presently unresolved protein structures. We discuss relatively straigh...

Animals that use astronomical cues to orientate must make continuous adjustment to account for temporal changes in azimuth caused by Earth's rotation. For example, the Monarch butterfly possesses a time-compensated sun compass dependent upon a circadian clock in the antennae. The amphipod Talitrus saltator possesses both a sun compass and a moon compass. We reasoned that the time-compensated co...

We present in this paper a method to incrementally estimate the heading of a robot using panoramic images grabbed while the robot moves in its environment. We present results that show a performance similar to a magnetic compass, if not better in some cases. In particular, the heading measured by the visual compass does not drift as normal odometry does, provided the robot turns roughly by the ...

Abstract. In general, eight target transverse spin-dependent azimuthal modulations are allowed in semi inclusive deep inelastic scattering of polarized leptons on a transversely polarized target. In the QCD parton model four of these asymmetries can be interpreted within the leading order approach. Two of them, namely Collins and Sivers effects were already measured by HERMES and COMPASS experi...