One of the principal models of magnetic sensing in migratory birds rests on the quantum spin dynamics of transient radical pairs created photochemically in ocular cryptochrome proteins. We consider here the role of electron spin entanglement and coherence in determining the sensitivity of a radical pair-based geomagnetic compass and the origins of the directional response. It emerges that the a...

In the years 2002-2004 COMPASS has collected data with the LiD target polarization oriented transversely with respect to the muon beam direction for about 20% of the running time, to measure transverse spin effects in semi-inclusive deep inelastic scattering, one of the main objectives of the COMPASS spin program. In 2007, COMPASS has used for the first time a proton NH3 target with the data ta...

In this paper, an overview of the concept mapping learning environment COMPASS is given. The most important features of COMPASS are the support of students in working out various concept mapping activities, the analysis of students’ concept maps, the qualitative and quantitative estimation of their knowledge, the provision of different forms of feedback and feedback components, the adaptive fun...

Following the seminal work of Unger et al. based on building mesh-like structures on top of a P2P network, we introduced an improved version of Compass a routing and load balancing algorithm based on direction-scopes for message delivery in such kind of networks. In this paper we evaluate and compare the performance of this scope-based Compass against the self-balanced and self-adaptive routing...

COMPASS is an on-axis 2.6 meter telescope coupled to a correlation polarimeter. The entire instrument was built specifically for CMB polarization studies. Careful attention was given to receiver and optics design, stability of the pointing platform, avoidance of systematic offsets, and development of data analysis techniques. Here we describe the experiment, its strengths and weaknesses, and th...

1 ∆G from high p T events at SMC and high p T analysis at COMPASS Measurements of the longitudinal spin cross section asymmetry for deep inelastic muon-nucleon interactions with two high transverse momentum hadrons (p T > 0.7 GeV) in the final state are presented for SMC data for polarized proton and deuteron and for data on polarized deuteron from COMPASS taken in 2002 and 2003. The muon asymm...

We investigate the origin of the cos 2φ azimuthal asymmetry in unpolarized semiinclusive DIS. The contributions to this asymmetry arising from the intrinsic transverse motion of quarks are explicitly evaluated, and predictions for the HERMES and COMPASS kinematic regimes are presented. We show that the effect of the leading-twist Boer-Mulders function h1 (x,k 2 T ), which describes a correlatio...

While the role of magnetic cues for compass orientation has been confirmed in numerous animals, the mechanism of detection is still debated. Two hypotheses have been proposed, one based on a light dependent mechanism, apparently used by birds and another based on a "compass organelle" containing the iron oxide particles magnetite (Fe(3)O(4)). Bats have recently been shown to use magnetic cues f...

To test if migratory monarch butterflies use polarized light patterns as part of their time-compensated sun compass, we recorded their virtual flight paths in a flight simulator while the butterflies were exposed to patches of naturally polarized blue sky, artificial polarizers or a sunny sky. In addition, we tested butterflies with and without the polarized light detectors of their compound ey...

ABSTRACT The star compass of birds, like the sun compass, is not innate. To possess either them, birds have to observe rotating sky and determine its centre rotation (in case compass) or sun's movement (for compass). Young are believed learn how use before their first migration, even though evidence this lacking. Here, we tested whether hand-raised Pied flycatchers (Ficedula hypoleuca) that had...