3,662 research outputs found
Preferences and Beliefs in a Sequential Social Dilemma: A Within-Subjects Analysis
Within-subject data from sequential social dilemma experiments reveal a correlation of first-and second-mover decisions for which two channels may be responsible, that our experiment allows to separate: i) a direct, preference-based channel that influences both first- and second-mover decisions; ii) an indirect channel, where second-mover decisions influence beliefs via a consensus effect, and the first-mover decision is a best response to these beliefs. We find strong evidence for the indirect channel: beliefs about second-mover cooperation are biased toward own second-mover behavior, and most subjects best respond to stated beliefs. But when first movers know the true probability of second-mover cooperation, subjects' own second moves still have predictive power regarding their first moves, suggesting that the direct channel also plays a role.experimental economics, consensus effect, social dilemmas
Cosmic ray spectral hardening due to dispersion in the source injection spectra
Recent cosmic ray (CR) experiments discovered that the CR spectra experience
a remarkable hardening for rigidity above several hundred GV. We propose that
this is caused by the superposition of the CR energy spectra of many sources
that have a dispersion in the injection spectral indices. Adopting similar
parameters as those of supernova remnants derived from the Fermi -ray
observations, we can reproduce the observational CR spectra of different
species well. This may be interpreted as evidence to support the supernova
remnant origin of CRs below the knee. We further propose that the same
mechanism may explain the "ankle" of the ultra high energy CR spectrum.Comment: 5 pages, 3 figures and 1 table. Updated with the diffusion
propagation model, accepted by Phys. Rev.
Possible "dawn" and "dusk" roles of light pulses shifting the phase of a circadian rhythm
A new automatic photoelectric method used in recording the eclosion rate of flies is described. The phase responses of the circadian rhythm of eclosion in Drosophila pseudoobscura to light pulses, of 1000 lx intensity and durations varying between 30 min and 12 h, were studied. The rhythm responds selectively either to the "on" or to the "off" transition of light pulses offered during the subjective night. The light pulses shift phase with the off transition during the first half of the night (dusk effect) and shift phase with the "on" transition during the second half of the night (dawn effect). The present findings are briefly discussed in the context of the work of other authors in this field
Interference Leakage Neutralization in Two-Hop Wiretap Channels with Partial CSI
In this paper, we analyze the four-node relay wiretap channel, where the relay performs amplify-and-forward. There is no direct link between transmitter and receiver available. The transmitter has multiple antennas, which assist in securing the transmission over both phases. In case of full channel state information (CSI), the transmitter can apply information leakage neutralization in order to prevent the eavesdropper from obtaining any information about the signal sent. This gets more challenging, if the transmitter has only an outdated estimate of the channel from the relay to the eavesdropper. For this case, we optimize the worst case secrecy rate by choosing intelligently the beamforming vectors and the power allocation at the transmitter and the relay
Blurring Borders: Innate Immunity with Adaptive Features
Adaptive immunity has often been considered the
penultimate of immune capacities. That system is now being
deconstructed to encompass less stringent rules that govern its
initiation, actual effector activity, and ambivalent results.
Expanding the repertoire of innate immunity found in all
invertebrates has greatly facilitated the relaxation of
convictions concerning what actually constitutes innate and
adaptive immunity. Two animal models, incidentally not on the line
of chordate evolution (C. elegans and
Drosophila), have contributed enormously to defining
homology. The characteristics of specificity and
memory and whether the antigen is pathogenic or nonpathogenic
reveal considerable information on homology, thus
deconstructing the more fundamentalist view. Senescence, cancer,
and immunosuppression often associated with mammals that possess
both innate and adaptive immunity also exist in invertebrates
that only possess innate immunity. Strict definitions become
blurred casting skepticism on the utility of creating rigid
definitions of what innate and adaptive immunity are without
considering overlaps
Cosmic-ray propagation properties for an origin in SNRs
We have studied the impact of cosmic-ray acceleration in SNR on the spectra
of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation
equation, which allows us to use analytical solutions for part of the problem
and an efficient numerical treatment of the remaining equations and thus
accurately describes the cosmic-ray propagation on small scales around their
sources in three spatial dimensions and time. We found strong variations of the
cosmic-ray nuclei flux by typically 20% with occasional spikes of much higher
amplitude, but only minor changes in the spectral distribution. The locally
measured spectra of primary cosmic rays fit well into the obtained range of
possible spectra. We further showed that the spectra of the secondary element
Boron show almost no variations, so that the above findings also imply
significant fluctuations of the Boron-to-Carbon ratio. Therefore the commonly
used method of determining CR propagation parameters by fitting
secondary-to-primary ratios appears flawed on account of the variations that
these ratios would show throughout the Galaxy.Comment: Accepted for publication in Ap
The Most Likely Sources of High Energy Cosmic-Ray Electrons in Supernova Remnants
Evidences of non-thermal X-ray emission and TeV gamma-rays from the supernova
remnants (SNRs) has strengthened the hypothesis that primary Galactic
cosmic-ray electrons are accelerated in SNRs. High energy electrons lose energy
via synchrotron and inverse Compton processes during propagation in the Galaxy.
Due to these radiative losses, TeV electrons liberated from SNRs at distances
larger than ~1 kpc, or times older than ~10^5 yr, cannot reach the solar
system. We investigated the cosmic-ray electron spectrum observed in the solar
system using an analytical method, and considered several candidate sources
among nearby SNRs which may contribute to the high energy electron flux.
Especially, we discuss the effects for the release time from SNRs after the
explosion, as well as the deviation of a source spectrum from a simple
power-law. From this calculation, we found that some nearby sources such as the
Vela, Cygnus Loop, or Monogem could leave unique signatures in the form of
identifiable structure in the energy spectrum of TeV electrons and show
anisotropies towards the sources, depending on when the electrons are liberated
from the remnant. This suggests that, in addition to providing information on
the mechanisms of acceleration and propagation of cosmic-rays, specific
cosmic-ray sources can be identified through the precise electron observation
in the TeV region.Comment: 32 pages, 6 figures, submitted to Ap
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