The polarization properties of Broad Absorption Line QSOs: observational results

Correlations between BAL QSO intrinsic properties and polarization have been searched for. Some results are summarized here, providing possible constraints on BAL outflow models.Comment: 4 pages, 5 figures; to appear in ``Mass Outflow in Active Galactic Nuclei: New Perspectives'' ASP Conference Series, eds. D.M. Crenshaw, S.B. Kraemer, and I.M. Georg

MIMAC-He3 : MIcro-tpc MAtrix of Chambers of He3

The project of a micro-TPC matrix of chambers of He3 for direct detection of non-baryonic dark matter is outlined. The privileged properties of He3 are highlighted. The double detection (ionization - projection of tracks) will assure the electron-recoil discrimination. The complementarity of MIMAC-He3 for supersymmetric dark matter search with respect to other experiments is illustrated. The modular character of the detector allows to have different gases to get A-dependence. The pressure degreee of freedom gives the possibility to work at high and low pressure. The low pressure regime gives the possibility to get the directionality of the tracks. The first measurements of ionization at very few keVs for He3 in He4 gas are described

Contingent attentional engagement: stimulus- and goal-driven capture have qualitatively different consequences

We examined whether shifting attention to a location necessarily entails extracting the features at that location, a process referred to as attentional engagement. In three spatial-cuing experiments ( N = 60), we found that an onset cue captured attention both when it shared the target's color and when it did not. Yet the effects of the match between the response associated with the cued object's identity and the response associated with the target (compatibility effects), which are diagnostic of attentional engagement, were observed only with relevant-color onset cues. These findings demonstrate that stimulus- and goal-driven capture have qualitatively different consequences: Before attention is reoriented to the target, it is engaged to the location of the critical distractor following goal-driven capture but not stimulus-driven capture. The reported dissociation between attentional shifts and attentional engagement suggests that attention is best described as a camera: One can align its zoom lens without pressing the shutter button

Attentional capture and engagement during the Attentional Blink: A “camera” metaphor of attention

Identification of a target is impaired when it follows a previous target within 500 ms, suggesting that our attentional system suffers from severe temporal limitations. Although control-disruption theories posit that such impairment, known as the attentional blink (AB), reflects a difficulty in matching incoming information with the current attentional set, disrupted-engagement theories propose that it reflects a delay in later processes leading to transient enhancement of potential targets. Here, we used a variant of the contingent-capture rapid serial visual presentation (RSVP) paradigm (Folk, Ester, & Troemel, 2009) to adjudicate these competing accounts. Our results show that a salient distractor that shares the target color captures attention to the same extent whether it appears within or outside the blink, thereby invalidating the notion that control over the attentional set is compromised during the blink. In addition, our results show that during the blink, not the attention-capturing object itself but the item immediately following it, is selected, indicating that the AB manifests as a delay between attentional capture and attentional engagement. We therefore conclude that attentional capture and attentional engagement can be dissociated as separate stages of attentional selection

Two Gap State Density in MgB2_{2}: A True Bulk Property or A Proximity Effect?

We report on the temperature dependence of the quasiparticle density of states (DOS) in the simple binary compound MgB2 directly measured using scanning tunneling microscope (STM). To achieve high quality tunneling conditions, a small crystal of MgB2 is used as a tip in the STM experiment. The ``sample'' is chosen to be a 2H-NbSe2 single crystal presenting an atomically flat surface. At low temperature the tunneling conductance spectra show a gap at the Fermi energy followed by two well-pronounced conductance peaks on each side. They appear at voltages V$_{S}\simeq \pm 3.8$ mV and V$_{L}\simeq \pm 7.8$ mV. With rising temperature both peaks disappear at the Tc of the bulk MgB2, a behavior consistent with the model of two-gap superconductivity. The explanation of the double-peak structure in terms of a particular proximity effect is also discussed.Comment: 4 pages, 3 figure