Testing quantum contextuality of continuous-variable states

We investigate the violation of noncontextuality by a class of continuous-variable states, including variations of entangled coherent states and a two-mode continuous superposition of coherent states. We generalize the Kochen-Specker (KS) inequality discussed by Cabello [A. Cabello, Phys. Rev. Lett. 101, 210401 (2008)] by using effective bidimensional observables implemented through physical operations acting on continuous-variable states, in a way similar to an approach to the falsification of Bell-Clauser-Horne-Shimony-Holt inequalities put forward recently. We test for state-independent violation of KS inequalities under variable degrees of state entanglement and mixedness. We then demonstrate theoretically the violation of a KS inequality for any two-mode state by using pseudospin observables and a generalized quasiprobability function.

Rotating massive main-sequence stars II. Simulating a population of LMC early B-type stars as a test of rotational mixing

Context. Rotational mixing in massive stars is a widely applied concept, with far-reaching consequences for stellar evolution, nucleosynthesis, and stellar explosions.

Tripartite nonlocality and continuous-variable entanglement in thermal states of trapped ions

We study a system of three trapped ions in an anisotropic bidimensional trap. By focusing on the transverse modes of the ions, we show that the mutual ion-ion Coulomb interactions set entanglement of a genuine tripartite nature, to some extent persistent to the thermal nature of the vibronic modes. We tackle this issue by addressing a nonlocality test in the phase space of the ionic system and quantifying the genuine residual tripartite entanglement in the continuous variable state of the transverse modes.

Stable breeding despite variable feeding in two sympatric auk species

Capsule Despite substantial inter-annual and inter-specific variance in the composition of chick diet, the breeding success of Guillemots (Common Murres) Uria aalge and Razorbills Alca torda remained constant from 2008 to 2010.
Aims To examine inter-specific and inter-annual differences in breeding success, chick provisioning behaviour and predation between two sympatric auk species.
Methods Focal observations of breeding auks at Rathlin Island, Northern Ireland, during 2008, 2009 and 2010 recorded reproductive success, reasons for breeding failure, prey composition and quality and chick provisioning rates.
Results Breeding success of both species was stable over the three years, despite significant variance in the composition and quality of the diet provided to chicks. Razorbills experienced greater rates of failure than Guillemots owing to chick loss and had lower overall breeding success.
Conclusion Guillemot and Razorbill breeding success was independent of the composition and quality of prey items delivered to chicks. Inter-specific differences in reproductive success may have been attributed to greater rates of predation at Razorbill rather than Guillemot nests.

SuperWASP observations of pulsating Am stars

We have studied over 1600 Am stars at a photometric precision of 1 mmag with SuperWASP photometric data. Contrary to previous belief, we find that around 200 Am stars are pulsating d Sct and ? Dor stars, with low amplitudes that have been missed in previous, less extensive studies. While the amplitudes are generally low, the presence of pulsation in Am stars places a strong constraint on atmospheric convection, and may require the pulsation to be laminar. While some pulsating Am stars have been previously found to be d Sct stars, the vast majority of Am stars known to pulsate are presented in this paper. They will form the basis of future statistical studies of pulsation in the presence of atomic diffusion. An extended version of Table 1 containing all the detected frequencies and amplitudes is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/535/A3

A search for line intensity enhancements in the far-UV spectra of active late-type stars arising from opacity

Context. Radiative transfer calculations have predicted intensity enhancements for optically thick emission lines, as opposed to the normal intensity reductions, for astrophysical plasmas under certain conditions. In particular, the results are predicted to be dependent both on the geometry of the emitting plasma and the orientation of the observer. Hence in principle the detection of intensity enhancement may provide a way of determining the geometry of an unresolved astronomical source.
Aims. To investigate such enhancements we have analysed a sample of active late-type stars observed in the far ultraviolet spectral region.
Methods. Emission lines of O vi in the FUSE satellite spectra of ϵ Eri, II Peg and Prox Cen were searched for intensity enhancements due to opacity.
Results. We have found strong evidence for line intensity enhancements due to opacity during active or flare-like activity for all three stars. The O vi 1032/1038 line intensity ratios, predicted to have a value of 2.0 in the optically thin case, are found to be up to ~30% larger during several orbital phases.
Conclusions. Our measurements, combined with radiative transfer models, allow us to constrain both the geometry of the O vi emitting regions in our stellar sources and the orientation of the observer. A spherical emitting plasma can be ruled out, as this would lead to no intensity enhancement. In addition, the theory tells us that the line-of-sight to the plasma must be close to perpendicular to its surface, as observations at small angles to the surface lead to either no intensity enhancement or the usual line intensity decrease over the optically thin value. For the future, we outline a laboratory experiment, that could be undertaken with current facilities, which would provide an unequivocal test of predictions of line intensity enhancement due to opacity, in particular the dependence on plasma geometry.

The VLT-FLAMES survey of massive stars: Nitrogen abundances for Be-type stars in the Magellanic Clouds

Aims. We compare the predictions of evolutionary models for early-type stars with atmospheric parameters, projected rotational velocities and nitrogen abundances estimated for a sample of Be-type stars. Our targets are located in 4 fields centred on the Large Magellanic Cloud cluster: NGC 2004 and the N 11 region as well as the Small Magellanic Cloud clusters: NGC 330 and NGC 346.

Progenitors of Core-Collapse Supernovae

Knowledge of the progenitors of core-collapse supernovae is a fundamental component in understanding the explosions. The recent progress in finding such stars is reviewed. The minimum initial mass that can produce a supernova (SN) has converged to 8 +/- 1 M-circle dot from direct detections of red supergiant progenitors of II-P SNe and the most massive white dwarf progenitors, although this value is model dependent. It appears that most type Ibc SNe arise from moderate mass interacting binaries. The highly energetic, broad-lined Ic SNe are likely produced by massive, Wolf-Rayet progenitors. There is some evidence to suggest that the majority of massive stars above similar to 20 M-circle dot may collapse quietly to black holes and that the explosions remain undetected. The recent discovery of a class of ultrabright type H SNe and the direct detection of some progenitor stars bearing luminous blue variable characteristics suggest some very massive stars do produce highly energetic explosions. The physical mechanism is under debate, and these SNe pose a challenge to stellar evolutionary theory.

DISPERSION IN THE WOOD MOUSE, APODEMUS-SYLVATICUS - VARIABLE RESOURCES IN TIME AND SPACE

(1) The abundance and dispersion of a population of Apodemus sylvaticus was investigated with respect to tree seed availability and vegetative structure over three harvests.