10,229 research outputs found
Private-public opinion discrepancy
In many Western societies there are rising concerns about increasing polarization in public debate. However, statistics on private attitudes paint a different picture: the average attitudes in societies are more moderate and remain rather stable over time. The present paper presents an agent-based model of how such discrepancies between public opinion and private attitudes develop at the scale of micro-societies. Based on social psychological theorizing, the model distinguishes between two types of agents: a) those seeking to gain or maintain a good reputation and status, and b) those seeking to promote group harmony by reaching consensus. We characterized these different types of agents by different decision rules for either voicing their opinion or remaining silent, based on the behavior of their proximal network. Results of the model simulations show that even when the private attitudes of the agents are held constant, publicly expressed opinions can oscillate and (depending on the reputational concerns of individual actors) situations can occur in which minorities as well as majorities are silenced. We conclude that the macro-level consequences of micro-level decisions to either voice an opinion or remain silent provide a foundation for better understanding how public opinions are shaped. Moreover, we discuss the conditions under which public opinion could be considered a good representation of private attitudes in a society
Soft breaking of symmetry: Light neutrino spectrum and Leptogenesis
Continuous symmetry can generate quasi degenerate mass
spectrum for both left handed light and right handed heavy Majorana neutrinos
assuming that the symmetry preserving non zero parameters are nearly same.
There is an accidental exchange symmetry in the light and heavy
neutrino Majorana mass terms. This implies and
. In addition it generates another zero mixing angle
and one zero mass difference. We restrict ourselves to type-I See-Saw mechanism
for generation of light neutrino mass. We have found that under
symmetry cosmological lepton asymmetry vanishes. We break
such a way that the exchange symmetry preserves
in the neutrino sector. We have seen that light neutrino phenomenology can be
explained under soft breaking of this symmetry. We have observed that softness
of this symmetry breaking depends on the degeneracy of the light neutrino mass
spectrum. Quasi-degeneracy of right handed neutrino mass spectrum opens an
option for resonant leptogenesis. The degeneracy of the right handed neutrino
mass spectrum is restricted through light neutrino data. We observed that for
generation of right sized baryon asymmetry common neutrino mass scale
have to be of the order of and corresponding
right handed neutrino mass scale have to be nearly GeV. We also have
discussed the effect of RG evolution on light neutrino spectrum and also on
baryon asymmetry.Comment: 21 pages, no figure, Revised with the comments on RG effec
The quadrupole moment of slowly rotating fluid balls
In this paper we use the second order formalism of Hartle to study slowly and
rigidly rotating stars with focus on the quadrupole moment of the object. The
second order field equations for the interior fluid are solved numerically for
different classes of possible equations of state and these solutions are then
matched to a vacuum solution that includes the general asymptotically flat
axisymmetric metric to second order, using the Darmois-Israel procedure. For
these solutions we find that the quadrupole moment differs from that of the
Kerr metric, as has also been found for some equations of state in other
studies. Further we consider the post-Minkowskian limit analytically. In the
paper we also illustrate how the relativistic multipole moments can be
calculated from a complex gravitational potential.Comment: 13 pages, 5 figure
From Newton's Laws to the Wheeler-DeWitt Equation
This is a pedagogical paper which explains some ideas in cosmology at a level
accessible to undergraduate students. It does not use general relativity, but
uses the ideas of Newtonian cosmology worked out by Milne and McCrea. The
cosmological constant is also introduced within a Newtonian framework.
Following standard quantization procedures the Wheeler-DeWitt equation in the
minisuperspace approximation is derived for empty and non-empty universes.Comment: 13 pages, 1 figur
The European Food Safety Authority scientific opinion on a risk profile related to production and consumption of insects as food and feed
The increased attention to the use of farmed insects as a novel protein source has raised the question of the safety of insects as human food and as animal feed. This was the background for the European Union (EU) Commission to mandate the European Food Safety Authority (EFSA) to conduct a review of the current knowledge about biological, chemical and environmental risks associated with production and consumption of insects. National authorities in some EU member states (Belgium, the Netherlands and France) have conducted national assessments (ANSES, 2015; FASFC, 2014; NVWA, 2014). However, in the EU, existing regulations constitute legal barriers for marketing insects for human consumption and as protein in animal feed for food producing animals
Resonant ion-pair formation in electron recombination with HF^+
The cross section for resonant ion-pair formation in the collision of
low-energy electrons with HF^+ is calculated by the solution of the
time-dependent Schrodinger equation with multiple coupled states using a wave
packet method. A diabatization procedure is proposed to obtain the electronic
couplings between quasidiabatic potentials of ^1Sigma^+ symmetry for HF. By
including these couplings between the neutral states, the cross section for
ion-pair formation increases with about two orders of magnitude compared with
the cross section for direct dissociation. Qualitative agreement with the
measured cross section is obtained. The oscillations in the calculated cross
section are analyzed. The cross section for ion-pair formation in electron
recombination with DF^+ is calculated to determine the effect of isotopic
substitution.Comment: 12 pages, 12 figure
'Designer atoms' for quantum metrology
Entanglement is recognized as a key resource for quantum computation and
quantum cryptography. For quantum metrology, the use of entangled states has
been discussed and demonstrated as a means of improving the signal-to-noise
ratio. In addition, entangled states have been used in experiments for
efficient quantum state detection and for the measurement of scattering
lengths. In quantum information processing, manipulation of individual quantum
bits allows for the tailored design of specific states that are insensitive to
the detrimental influences of an environment. Such 'decoherence-free subspaces'
protect quantum information and yield significantly enhanced coherence times.
Here we use a decoherence-free subspace with specifically designed entangled
states to demonstrate precision spectroscopy of a pair of trapped Ca+ ions; we
obtain the electric quadrupole moment, which is of use for frequency standard
applications. We find that entangled states are not only useful for enhancing
the signal-to-noise ratio in frequency measurements - a suitably designed pair
of atoms also allows clock measurements in the presence of strong technical
noise. Our technique makes explicit use of non-locality as an entanglement
property and provides an approach for 'designed' quantum metrology
Observational Evidence of Accretion Disk-Caused Jet Precession in Galactic Nuclei
We show that the observational data of extragalactic radio sources tend to
support the theoretical relationship between the jet precession period and the
optical luminosity of the sources, as predicted by the model in which an
accretion disk causes the central black hole to precess.Comment: 13 pages, 1 figure, accepted for publication in ApJ Letter
Direct observation of the oxygen isotope effect on the in-plane magnetic field penetration depth in optimally doped YBaCuO
We report the first direct observation of the oxygen-isotope
(O/O) effect on the in-plane penetration depth in
a nearly optimally doped YBaCuO film using the novel
low-energy muon-spin rotation technique. Spin polarized low energy muons are
implanted in the film at a known depth beneath the surface and precess in
the local magnetic field . This feature allows us to measure directly the
profile of the magnetic field inside the superconducting film in the
Meissner state and to make a model independent determination of .
A substantial isotope shift % at 4 K is
observed, implying that the in-plane effective supercarrier mass
is oxygen-isotope dependent with .Comment: 4 pages, 2 figure
Treatment of hypophosphatemia in the intensive care unit: a review
Introduction: Currently no evidence-based guideline exists for the approach to hypophosphatemia in critically ill patients. Methods: We performed a narrative review of the medical literature to identify the incidence, symptoms, and treatment of hypophosphatemia in critically ill patients. Specifically, we searched for answers to the questions whether correction of hypophosphatemia is associated with improved outcome, and whether a certain treatment strategy is superior. Results: Incidence: hypophosphatemia is frequently encountered in the intensive care unit; and critically ill patients are at increased risk for developing hypophosphatemia due to the presence of multiple causal factors. Symptoms: hypophosphatemia may lead to a multitude of symptoms, including cardiac and respiratory failure. Treatment: hypophosphatemia is generally corrected when it is symptomatic or severe. However, although multiple studies confirm the efficacy and safety of intravenous phosphate administration, it remains uncertain when and how to correct hypophosphatemia. Outcome: in some studies, hypophosphatemia was associated with higher mortality; a paucity of randomized controlled evidence exists for whether correction of hypophosphatemia improves the outcome in critically ill patients. Conclusions: Additional studies addressing the current approach to hypophosphatemia in critically ill patients are required. Studies should focus on the association between hypophosphatemia and morbidity and/or mortality, as well as the effect of correction of this electrolyte disorde
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