1,044 research outputs found
Fear Conditioning to Subliminal Fear Relevant and Non Fear Relevant Stimuli
A growing body of evidence suggests that conscious visual awareness is not a prerequisite for human fear learning. For instance, humans can learn to be fearful of subliminal fear relevant images – images depicting stimuli thought to have been fear relevant in our evolutionary context, such as snakes, spiders, and angry human faces. Such stimuli could have a privileged status in relation to manipulations used to suppress usually salient images from awareness, possibly due to the existence of a designated sub-cortical ‘fear module’. Here we assess this proposition, and find it wanting. We use binocular masking to suppress awareness of images of snakes and wallabies (particularly cute, non-threatening marsupials). We find that subliminal presentations of both classes of image can induce differential fear conditioning. These data show that learning, as indexed by fear conditioning, is neither contingent on conscious visual awareness nor on subliminal conditional stimuli being fear relevant
Radiation effects in glasses used for immobilization of high-level waste and plutonium disposition
This paper is a comprehensive review of the state-of-knowledge in the field of radiation effects in glasses that are to be used for the immobilization of high-level nuclear waste and plutonium disposition. The current status and issues in the area of radiation damage processes, defect generation, microstructure development, theoretical methods and experimental methods ase reviewed. Questions of fundamental and technological interest that offer opportunities for research are identified
Skyrmion Multi-Walls
Skyrmion walls are topologically-nontrivial solutions of the Skyrme system
which are periodic in two spatial directions. We report numerical
investigations which show that solutions representing parallel multi-walls
exist. The most stable configuration is that of the square -wall, which in
the limit becomes the cubically-symmetric Skyrme crystal. There is
also a solution resembling parallel hexagonal walls, but this is less stable.Comment: 7 pages, 1 figur
The complex response of Arctic aerosol to sea-ice retreat
Loss of summertime Arctic sea ice will lead to a large increase in the emission of aerosols and precursor gases from the ocean surface. It has been suggested that these enhanced emissions will exert substantial aerosol radiative forcings, dominated by the indirect effect of aerosol on clouds. Here, we investigate the potential for these indirect forcings using a global aerosol microphysics model evaluated against aerosol observations from the Arctic Summer Cloud Ocean Study (ASCOS) campaign to examine the response of Arctic cloud condensation nuclei (CCN) to sea-ice retreat. In response to a complete loss of summer ice, we find that north of 70° N emission fluxes of sea salt, marine primary organic aerosol (OA) and dimethyl sulfide increase by a factor of ~ 10, ~ 4 and ~ 15 respectively. However, the CCN response is weak, with negative changes over the central Arctic Ocean. The weak response is due to the efficient scavenging of aerosol by extensive drizzling stratocumulus clouds. In the scavenging-dominated Arctic environment, the production of condensable vapour from oxidation of dimethyl sulfide grows particles to sizes where they can be scavenged. This loss is not sufficiently compensated by new particle formation, due to the suppression of nucleation by the large condensation sink resulting from sea-salt and primary OA emissions. Thus, our results suggest that increased aerosol emissions will not cause a climate feedback through changes in cloud microphysical and radiative properties
Black holes in supergravity and integrability
Stationary black holes of massless supergravity theories are described by
certain geodesic curves on the target space that is obtained after dimensional
reduction over time. When the target space is a symmetric coset space we make
use of the group-theoretical structure to prove that the second order geodesic
equations are integrable in the sense of Liouville, by explicitly constructing
the correct amount of Hamiltonians in involution. This implies that the
Hamilton-Jacobi formalism can be applied, which proves that all such black hole
solutions, including non-extremal solutions, possess a description in terms of
a (fake) superpotential. Furthermore, we improve the existing integration
method by the construction of a Lax integration algorithm that integrates the
second order equations in one step instead of the usual two step procedure. We
illustrate this technology with a specific example.Comment: 44 pages, small typos correcte
Disfluency in dialogue:an intentional signal from the speaker?
Disfluency is a characteristic feature of spontaneous human speech, commonly seen as a consequence of problems with production. However, the question remains open as to why speakers are disfluent: Is it a mechanical by-product of planning difficulty, or do speakers use disfluency in dialogue to manage listeners' expectations? To address this question, we present two experiments investigating the production of disfluency in monologue and dialogue situations. Dialogue affected the linguistic choices made by participants, who aligned on referring expressions by choosing less frequent names for ambiguous images where those names had previously been mentioned. However, participants were no more disfluent in dialogue than in monologue situations, and the distribution of types of disfluency used remained constant. Our evidence rules out at least a straightforward interpretation of the view that disfluencies are an intentional signal in dialogue. © 2012 Psychonomic Society, Inc
On Poincare and logarithmic Sobolev inequalities for a class of singular Gibbs measures
This note, mostly expository, is devoted to Poincar{\'e} and log-Sobolev
inequalities for a class of Boltzmann-Gibbs measures with singular interaction.
Such measures allow to model one-dimensional particles with confinement and
singular pair interaction. The functional inequalities come from convexity. We
prove and characterize optimality in the case of quadratic confinement via a
factorization of the measure. This optimality phenomenon holds for all beta
Hermite ensembles including the Gaussian unitary ensemble, a famous exactly
solvable model of random matrix theory. We further explore exact solvability by
reviewing the relation to Dyson-Ornstein-Uhlenbeck diffusion dynamics admitting
the Hermite-Lassalle orthogonal polynomials as a complete set of
eigenfunctions. We also discuss the consequence of the log-Sobolev inequality
in terms of concentration of measure for Lipschitz functions such as maxima and
linear statistics.Comment: Minor improvements. To appear in Geometric Aspects of Functional
Analysis -- Israel Seminar (GAFA) 2017-2019", Lecture Notes in Mathematics
225
Constraints on chiral operators in N=2 SCFTs
Open Access, © The Authors. Article funded by SCOAP3.
This article is distributed under the terms of the Creative Commons
Attribution License (
CC-BY 4.0
), which permits any use, distribution and reproduction in
any medium, provided the original author(s) and source are credited
The influence of the accessory genome on bacterial pathogen evolution
Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens’ frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorise the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution
Baryon Washout, Electroweak Phase Transition, and Perturbation Theory
We analyze the conventional perturbative treatment of sphaleron-induced
baryon number washout relevant for electroweak baryogenesis and show that it is
not gauge-independent due to the failure of consistently implementing the
Nielsen identities order-by-order in perturbation theory. We provide a
gauge-independent criterion for baryon number preservation in place of the
conventional (gauge-dependent) criterion needed for successful electroweak
baryogenesis. We also review the arguments leading to the preservation
criterion and analyze several sources of theoretical uncertainties in obtaining
a numerical bound. In various beyond the standard model scenarios, a realistic
perturbative treatment will likely require knowledge of the complete two-loop
finite temperature effective potential and the one-loop sphaleron rate.Comment: 25 pages, 9 figures; v2 minor typos correcte
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