1,358 research outputs found
The responses of people to virtual humans in an immersive virtual environment
This paper presents an experiment investigating the impact of behavior and responsiveness
on social responses to virtual humans in an immersive virtual environment
(IVE). A number of responses are investigated, including presence, copresence, and
two physiological responsesâheart rate and electrodermal activity (EDA). Our
findings suggest that increasing agentsâ responsiveness even on a simple level can
have a significant impact on certain aspects of peopleâs social responses to humanoid
agents.
Despite being aware that the agents were computer-generated, participants with
higher levels of social anxiety were significantly more likely to avoid âdisturbingâ
them. This suggests that on some level people can respond to virtual humans as
social actors even in the absence of complex interaction.
Responses appear to be shaped both by the agentsâ behaviors and by peopleâs expectations
of the technology. Participants experienced a significantly higher sense of
personal contact when the agents were visually responsive to them, as opposed to
static or simply moving. However, this effect diminished with experienced computer
users. Our preliminary analysis of objective heart-rate data reveals an identical pattern
of responses
High energy neutrinos from a slow jet model of core collapse supernovae
It has been hypothesized recently that core collapse supernovae are triggered
by mildly relativistic jets following observations of radio properties of these
explosions. Association of a jet, similar to a gamma-ray burst jet but only
slower, allows shock acceleration of particles to high energy and non-thermal
neutrino emission from a supernova. Detection of these high energy neutrinos in
upcoming kilometer scale Cherenkov detectors may be the only direct way to
probe inside these astrophysical phenomena as electromagnetic radiation is
thermal and contains little information. Calculation of high energy neutrino
signal from a simple and slow jet model buried inside the pre-supernova star is
reviewed here. The detection prospect of these neutrinos in water or ice
detector is also discussed in this brief review. Jetted core collapse
supernovae in nearby galaxies may provide the strongest high energy neutrino
signal from point sources.Comment: 17 pages, 5 figures, invited brief revie
Addendum to "Coherent radio pulses from GEANT generated electromagnetic showers in ice"
We reevaluate our published calculations of electromagnetic showers generated
by GEANT 3.21 and the radio frequency pulses they produce in ice. We are
prompted by a recent report showing that GEANT 3.21-modeled showers are
sensitive to internal settings in the electron tracking subroutine. We report
the shower and pulse characteristics obtained with different settings of GEANT
3.21 and with GEANT 4. The default setting of electron tracking in GEANT 3.21
we used in previous work speeds up the shower simulation at the cost of
information near the end of the tracks. We find that settings tracking electron
and positron to lower energy yield a more accurate calculation, a more intense
shower, and proportionately stronger radio pulses at low frequencies. At high
frequencies the relation between shower tracking algorithm and pulse spectrum
is more complex. We obtain radial distributions of shower particles and phase
distributions of pulses from 100 GeV showers that are consistent with our
published results.Comment: 4 pages, 3 figure
Signatures of photon and axion-like particle mixing in the gamma-ray burst jet
Photons couple to Axion-Like Particles (ALPs) or more generally to any pseudo
Nambu-Goldstone boson in the presence of an external electromagnetic field.
Mixing between photons and ALPs in the strong magnetic field of a Gamma-Ray
Burst (GRB) jet during the prompt emission phase can leave observable imprints
on the gamma-ray polarization and spectrum. Mixing in the intergalactic medium
is not expected to modify these signatures for ALP mass > 10^(-14) eV and/or
for < nG magnetic field. We show that the depletion of photons due to
conversion to ALPs changes the linear degree of polarization from the values
predicted by the synchrotron model of gamma ray emission. We also show that
when the magnetic field orientation in the propagation region is perpendicular
to the field orientation in the production region, the observed synchrotron
spectrum becomes steeper than the theoretical prediction and as detected in a
sizable fraction of GRB sample. Detection of the correlated polarization and
spectral signatures from these steep-spectrum GRBs by gamma-ray polarimeters
can be a very powerful probe to discover ALPs. Measurement of gamma-ray
polarization from GRBs in general, with high statistics, can also be useful to
search for ALPs.Comment: 17 pages, 3 figures. Accepted for publication in JCAP with minor
change
Neutrino mass hierarchy extraction using atmospheric neutrinos in ice
We show that the measurements of 10 GeV atmospheric neutrinos by an upcoming
array of densely packed phototubes buried deep inside the IceCube detector at
the South Pole can be used to determine the neutrino mass hierarchy for values
of sin^2(2theta13) close to the present bound, if the hierarchy is normal.
These results are obtained for an exposure of 100 Mton years and systematic
uncertainties up to 10%.Comment: Phys.Rev.D accepted version. Minor changes and 1 new figure (11
pages, 8 figures
Flavor conversion of cosmic neutrinos from hidden jets
High energy cosmic neutrino fluxes can be produced inside relativistic jets
under the envelopes of collapsing stars. In the energy range E ~ (0.3 - 1e5)
GeV, flavor conversion of these neutrinos is modified by various matter effects
inside the star and the Earth. We present a comprehensive (both analytic and
numerical) description of the flavor conversion of these neutrinos which
includes: (i) oscillations inside jets, (ii) flavor-to-mass state transitions
in an envelope, (iii) loss of coherence on the way to observer, and (iv)
oscillations of the mass states inside the Earth. We show that conversion has
several new features which are not realized in other objects, in particular
interference effects ("L- and H- wiggles") induced by the adiabaticity
violation. The neutrino-neutrino scattering inside jet and inelastic neutrino
interactions in the envelope may produce some additional features at E > 1e4
GeV. We study dependence of the probabilities and flavor ratios in the
matter-affected region on angles theta13 and theta23, on the CP-phase delta, as
well as on the initial flavor content and density profile of the star. We show
that measurements of the energy dependence of the flavor ratios will, in
principle, allow to determine independently the neutrino and astrophysical
parameters.Comment: 56 pages, 19 figures. Minor changes. Accepted by JHEP
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