11,920 research outputs found
Bayesian Inference of Social Norms as Shared Constraints on Behavior
People act upon their desires, but often, also act in adherence to implicit
social norms. How do people infer these unstated social norms from others'
behavior, especially in novel social contexts? We propose that laypeople have
intuitive theories of social norms as behavioral constraints shared across
different agents in the same social context. We formalize inference of norms
using a Bayesian Theory of Mind approach, and show that this computational
approach provides excellent predictions of how people infer norms in two
scenarios. Our results suggest that people separate the influence of norms and
individual desires on others' actions, and have implications for modelling
generalizations of hidden causes of behavior.Comment: 7 pages, 5 figures, to appear in CogSci 2019, code available at
https://github.com/ztangent/norms-cogsci1
Noise spectra of stochastic pulse sequences: application to large scale magnetization flips in the finite size 2D Ising model
We provide a general scheme to predict and derive the contribution to the
noise spectrum of a stochastic sequence of pulses from the distribution of
pulse parameters. An example is the magnetization noise spectra of a 2D Ising
system near its phase transition. At , the low frequency spectra is
dominated by magnetization flips of nearly the entire system. We find that both
the predicted and the analytically derived spectra fit those produced from
simulations. Subtracting this contribution leaves the high frequency spectra
which follow a power law set by the critical exponents.Comment: 4 pages, 5 figures. We improved text and included a predicted noise
curve in Figure 4. 2 examples from Figure 3 are remove
Spin-current Seebeck effect in quantum dot systems
We first bring up the concept of spin-current Seebeck effect based on a
recent experiment [Nat. Phys. {\bf 8}, 313 (2012)], and investigate the
spin-current Seebeck effect in quantum dot (QD) systems. Our results show that
the spin-current Seebeck coefficient is sensitive to different polarization
states of QD, and therefore can be used to detect the polarization state of QD
and monitor the transitions between different polarization states of QD. The
intradot Coulomb interaction can greatly enhance the due to the stronger
polarization of QD. By using the parameters for a typical QD, we demonstrate
that the maximum can be enhanced by a factor of 80. On the other hand, for
a QD whose Coulomb interaction is negligible, we show that one can still obtain
a large by applying an external magnetic field.Comment: 6 pages, 8 figure
Modulation of Neurally Mediated Vasodepression and Bradycardia by Electroacupuncture through Opioids in Nucleus Tractus Solitarius.
Stimulation of vagal afferent endings with intravenous phenylbiguanide (PBG) causes both bradycardia and vasodepression, simulating neurally mediated syncope. Activation of µ-opioid receptors in the nucleus tractus solitarius (NTS) increases blood pressure. Electroacupuncture (EA) stimulation of somatosensory nerves underneath acupoints P5-6, ST36-37, LI6-7 or G37-39 selectively but differentially modulates sympathoexcitatory responses. We therefore hypothesized that EA-stimulation at P5-6 or ST36-37, but not LI6-7 or G37-39 acupoints, inhibits the bradycardia and vasodepression through a µ-opioid receptor mechanism in the NTS. We observed that stimulation at acupoints P5-6 and ST36-37 overlying the deep somatosensory nerves and LI6-7 and G37-39 overlying cutaneous nerves differentially evoked NTS neural activity in anesthetized and ventilated animals. Thirty-min of EA-stimulation at P5-6 or ST36-37 reduced the depressor and bradycardia responses to PBG while EA at LI6-7 or G37-39 did not. Congruent with the hemodynamic responses, EA at P5-6 and ST36-37, but not at LI6-7 and G37-39, reduced vagally evoked activity of cardiovascular NTS cells. Finally, opioid receptor blockade in the NTS with naloxone or a specific μ-receptor antagonist reversed P5-6 EA-inhibition of the depressor, bradycardia and vagally evoked NTS activity. These data suggest that point specific EA stimulation inhibits PBG-induced vasodepression and bradycardia responses through a μ-opioid mechanism in the NTS
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Paraventricular Nucleus Modulates Excitatory Cardiovascular Reflexes during Electroacupuncture.
The paraventricular nucleus (PVN) regulates sympathetic outflow and blood pressure. Somatic afferent stimulation activates neurons in the hypothalamic PVN. Parvocellular PVN neurons project to sympathoexcitatory cardiovascular regions of the rostral ventrolateral medulla (rVLM). Electroacupuncture (EA) stimulates the median nerve (P5-P6) to modulate sympathoexcitatory responses. We hypothesized that the PVN and its projections to the rVLM participate in the EA-modulation of sympathoexcitatory cardiovascular responses. Cats were anesthetized and ventilated. Heart rate and mean blood pressure were monitored. Application of bradykinin every 10-min on the gallbladder induced consistent pressor reflex responses. Thirty-min of bilateral EA stimulation at acupoints P5-P6 reduced the pressor responses for at least 60-min. Inhibition of the PVN with naloxone reversed the EA-inhibition. Responses of cardiovascular barosensitive rVLM neurons evoked by splanchnic nerve stimulation were reduced by EA and then restored with opioid receptor blockade in the PVN. EA at P5-P6 decreased splanchnic evoked activity of cardiovascular barosensitive PVN neurons that also project directly to the rVLM. PVN neurons labeled with retrograde tracer from rVLM were co-labeled with μ-opioid receptors and juxtaposed to endorphinergic fibers. Thus, the PVN and its projection to rVLM are important in processing acupuncture modulation of elevated blood pressure responses through a PVN opioid mechanism
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