1,655 research outputs found
Recalibrating valence weighting biases to promote changes in rejection sensitivity and risk-taking
Past research has found that modifying individuals' valence weighting tendencies by recalibrating them to weight positive and negative valence in a more balanced manner influenced a variety of judgments. The current research examines the utility of the recalibration procedure as a targeted intervention. In Experiment 1, we recruited participants high in rejection sensitivity (who are known to exhibit a negative weighting bias) and in Experiment 2, we recruited participants with high risk tendencies (who are known to exhibit a positive weighting bias). In both experiments, participants first played BeanFest, in which they were presented with beans varying in shape and speckles and learned which increased or decreased points. They later classified the game beans, as well as novel ones varying in their resemblance to the known positives or known negatives, as good or bad. In the recalibration condition, participants were told if they classified each bean correctly, thus receiving feedback regarding the appropriate weighting of resemblance to a known positive versus a negative. The controls, who received no feedback, were less accurate at classifying the novel the beans than the recalibration participants. Furthermore, in Experiment 1, the recalibration condition subsequently exhibited lower sensitivity to rejection than the control condition, with this reduction being stronger for individuals initially higher in rejection sensitivity. This effect was still present a week later. In Experiment 2, the recalibration condition reported diminished risk-tendencies, again with this effect being stronger for individuals with initially higher riskiness, and persisting for a week. Even more importantly, recalibration participants also engaged in less risky behavior on a laboratory task
A Model for QCD at High Density and Large Quark Mass
We study the high density region of QCD within an effective model obtained in
the frame of the hopping parameter expansion and choosing Polyakov type of
loops as the main dynamical variables representing the fermionic matter. To get
a first idea of the phase structure, the model is analyzed in strong coupling
expansion and using a mean field approximation. In numerical simulations, the
model still shows the so-called sign problem, a difficulty peculiar to non-zero
chemical potential, but it permits the development of algorithms which ensure a
good overlap of the Monte Carlo ensemble with the true one. We review the main
features of the model and present calculations concerning the dependence of
various observables on the chemical potential and on the temperature, in
particular of the charge density and the diquark susceptibility, which may be
used to characterize the various phases expected at high baryonic density. We
obtain in this way information about the phase structure of the model and the
corresponding phase transitions and cross over regions, which can be considered
as hints for the behaviour of non-zero density QCD.Comment: 21 pages, 29 figure
The weighting of positive vs. negative valence and its impact on the formation of social relationships
Forming social relationships is an integral aspect of our lives and a topic fundamental to social psychology. Using a performance-based measure of individual differences in valence weighting, we demonstrate that the extent to which first-year college students weight positive versus negative valence when engaged in attitude generalization predicts how many peer relationships they develop during the subsequent two months (Study 1). Furthermore, we show that individuals strategically recruited for their high sensitivity to interpersonal rejection benefit from an intervention that recalibrates their valence-weighting tendencies from an overweighting of negative valence to a more balanced weighting of positive and negative valence (Study 2). Recalibration led to extended decreases in participants' rejection sensitivity and, most importantly, led them to develop more social relationships over a subsequent two-week period. These findings demonstrate that the weighting of positive versus negative valence is a fundamental process that influences complex social outcomes and that such valence weighting tendencies can be recalibrated so as to benefit individuals
Group Field Theory: An overview
We give a brief overview of the properties of a higher dimensional
generalization of matrix model which arises naturally in the context of a
background independent approach to quantum gravity, the so called group field
theory. We show that this theory leads to a natural proposal for the physical
scalar product of quantum gravity. We also show in which sense this theory
provides a third quantization point of view on quantum gravity.Comment: 10 page
A spin foam model for pure gauge theory coupled to quantum gravity
We propose a spin foam model for pure gauge fields coupled to Riemannian
quantum gravity in four dimensions. The model is formulated for the
triangulation of a four-manifold which is given merely combinatorially. The
Riemannian Barrett--Crane model provides the gravity sector of our model and
dynamically assigns geometric data to the given combinatorial triangulation.
The gauge theory sector is a lattice gauge theory living on the same
triangulation and obtains from the gravity sector the geometric information
which is required to calculate the Yang--Mills action. The model is designed so
that one obtains a continuum approximation of the gauge theory sector at an
effective level, similarly to the continuum limit of lattice gauge theory, when
the typical length scale of gravity is much smaller than the Yang--Mills scale.Comment: 18 pages, LaTeX, 1 figure, v2: details clarified, references adde
A new Eocene species of presbyornithid (Aves, Anseriformes) from Murgon, Australia
The taxa found in an Eocene deposit, near Murgon, Queensland, the only pre-Oligocene Paleogene site recording a terrestrial vertebrate fauna from Australia, are very significant for the insight they provide concerning the evolution of the Australian biota. Here we resolve the identity of fossils previously referred to the Graculavidae, waterbirds of then unresolved affinities. We taxonomically describe the first bird to be named from this fauna, Murgonornis archeri gen. et sp. nov., Presbyornithidae. Our findings reveal that presbyornithids were widespread globally in the earliest Eocene, and that this family had a history on Australia from at least 55 Ma until ca. 24 Ma, when they disappear from the fossil record
so(4) Plebanski Action and Relativistic Spin Foam Model
In this note we study the correspondence between the ``relativistic spin
foam'' model introduced by Barrett, Crane and Baez and the so(4) Plebanski
action. We argue that the Plebanski model is the continuum analog of
the relativistic spin foam model. We prove that the Plebanski action possess
four phases, one of which is gravity and outline the discrepancy between this
model and the model of Euclidean gravity. We also show that the Plebanski model
possess another natural dicretisation and can be associate with another, new,
spin foam model that appear to be the counterpart of the spin foam
model describing the self dual formulation of gravity.Comment: 12 pages, REVTeX using AMS fonts. Some minor corrections and
improvement
Exact and semiclassical approach to a class of singular integral operators arising in fluid mechanics and quantum field theory
A class of singular integral operators, encompassing two physically relevant
cases arising in perturbative QCD and in classical fluid dynamics, is presented
and analyzed. It is shown that three special values of the parameters allow for
an exact eigenfunction expansion; these can be associated to Riemannian
symmetric spaces of rank one with positive, negative or vanishing curvature.
For all other cases an accurate semiclassical approximation is derived, based
on the identification of the operators with a peculiar Schroedinger-like
operator.Comment: 12 pages, 1 figure, amslatex, bibtex (added missing label eq.11
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