13,293 research outputs found
Mechanisms for Lasing with Cold Atoms as the Gain Medium
We realize a laser with a cloud of cold rubidium atoms as gain medium, placed
in a low-finesse cavity. Three different regimes of laser emission are observed
corresponding respectively to Mollow, Raman and Four Wave Mixing mechanisms. We
measure an output power of up to 300 W and present the main properties of
these different lasers in each regime
Tunable Oscillations in the Purkinje Neuron
In this paper, we study the dynamics of slow oscillations in Purkinje neurons
in vitro, and derive a strong association with a forced parametric oscillator
model. We demonstrate the precise rhythmicity of the oscillations in Purkinje
neurons, as well as a dynamic tunability of this oscillation using a
photo-switchable compound. We show that this slow oscillation can be induced in
every Purkinje neuron, having periods ranging between 10-25 seconds. Starting
from a Hodgkin-Huxley model, we also demonstrate that this oscillation can be
externally modulated, and that the neurons will return to their intrinsic
firing frequency after the forced oscillation is concluded. These results
signify an additional functional role of tunable oscillations within the
cerebellum, as well as a dynamic control of a time scale in the brain in the
range of seconds.Comment: 12 pages, 5 figure
How groups react to disloyalty in the context of intergroup competition: Evaluations of group deserters and defectors
Groups strongly value loyalty, especially in the context of intergroup competition. However, research has yet to investigate how groups respond to members who leave the group or join a competing outgroup. Three studies investigated groups' reactions to defectors (Experiment 1) and deserting members (Experiments 2 and 3). Experiment 1 used a minimal group paradigm to demonstrate that defectors trigger a stronger derogation of ingroup deviants than outgroup deviants vis-Ã -vis normative members. Experiments 2 and 3 compared group members' responses to defection versus desertion from minimal and self-assigned groups, respectively. Experiment 3 also explored an explanation for the evaluations of disloyalty. Across studies, participants evaluated normative ingroup members more positively than defectors and deserters. Outgroup deserting and defecting members were evaluated similarly. Derogation of ingroup as compared to outgroup targets emerged only for defectors. In addition, Experiment 3 demonstrated that negativity toward the outgroup was related to stronger derogation of disloyal targets. Negative outgroup attitudes trigger stricter criteria for responding to disloyalty. Directions for future research are discussed
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