963 research outputs found
Aging with Elevated Autistic Traits: Cognitive Functioning Among Older Adults with the Broad Autism Phenotype
Background: Little is known about the impact of aging with autism spectrum disorder (ASD) on cognition. As a first step in addressing this gap in our knowledge, the current study examined cognitive functioning among older adults with elevated, but subclinical levels of autistic traits (i.e., the Broad Autism Phenotype; BAP) compared to older adults without the BAP.
Method: Forty older adults (aged 60-91, M=73 years) were recruited and classified as meeting criteria for the BAP (n=20) or not (control older adults, COA; n=20). Different components of executive function as well as episodic memory were measured using standardized performance-based neuropsychological assessments in addition to a self-report questionnaire of executive function difficulties.
Results: Despite no differences in age, sex ratio, educational history or IQ, the BAP group demonstrated poorer performance on measures of executive function and episodic memory compared to the COA group. The BAP group also self-reported more executive function difficulties in everyday settings. Moreover, differences in working memory and attentional shifting were maintained after accounting for the influences of IQ and both depression and anxiety symptoms.
Conclusions: These findings suggest that aging with the BAP confers additional risk to cognitive function for older adults. As the BAP forms a bridge in the continuum from typical to atypical levels of autistic traits, these findings suggest that individuals with ASD might also incur cognitive costs as they age into older adulthood
Gauss-Bonnet Black Holes and Heavy Fermion Metals
We consider charged black holes in Einstein-Gauss-Bonnet Gravity with
Lifshitz boundary conditions. We find that this class of models can reproduce
the anomalous specific heat of condensed matter systems exhibiting
non-Fermi-liquid behaviour at low temperatures. We find that the temperature
dependence of the Sommerfeld ratio is sensitive to the choice of Gauss-Bonnet
coupling parameter for a given value of the Lifshitz scaling parameter. We
propose that this class of models is dual to a class of models of
non-Fermi-liquid systems proposed by Castro-Neto et.al.Comment: 17 pages, 6 figures, pdfLatex; small corrections to figure 10 in this
versio
Effects of temperature on thick branes and the fermion (quasi-)localization
Following Campos's work [Phys. Rev. Lett. 88, 141602 (2002)], we investigate
the effects of temperature on flat, de Sitter (dS), and anti-de Following
Campos's work [Phys. Rev. Lett. \textbf{88}, 141602 (2002)], we investigate the
effects of temperature on flat, de Sitter (dS), and anti-de Sitter (AdS) thick
branes in five-dimensional (5D) warped spacetime, and on the fermion
(quasi-)localization. First, in the case of flat brane, when the critical
temperature reaches, the solution of the background scalar field and the warp
factor is not unique. So the thickness of the flat thick brane is uncertain at
the critical value of the temperature parameter, which is found to be lower
than the one in flat 5D spacetime. The mass spectra of the fermion Kaluza-Klein
(KK) modes are continuous, and there is a series of fermion resonances. The
number and lifetime of the resonances are finite and increase with the
temperature parameter, but the mass of the resonances decreases with the
temperature parameter. Second, in the case of dS brane, we do not find such a
critical value of the temperature parameter. The mass spectra of the fermion KK
modes are also continuous, and there is a series of fermion resonances. The
effects of temperature on resonance number, lifetime, and mass are the same
with the case of flat brane. Last, in the case of AdS brane, {the critical
value of the temperature parameter can less or greater than the one in the flat
5D spacetime.} The spectra of fermion KK modes are discrete, and the mass of
fermion KK modes does not decrease monotonically with increasing temperature
parameter.Comment: 24 pages, 15 figures, published versio
Ion beam irradiation of ABO4 compounds with the fergusonite, monazite, scheelite, and zircon structures
Lessons from the decoupling limit of Horava gravity
We consider the so-called "healthy" extension of Horava gravity in the limit
where the Stuckelberg field decouples from the graviton. We verify the alleged
strong coupling problem in this limit, under the assumption that no large
dimensionless parameters are put in by hand. This follows from the fact that
the dispersion relation for the Stuckelberg field does not have the desired z =
3 anisotropic scaling in the UV. To get the desired scaling and avoid strong
coupling one has to introduce a low scale of Lorentz violation and retain some
coupling between the graviton and the Stuckelberg field. We also make use of
the foliation preserving symmetry to show how the Stuckelberg field couples to
some violation of energy conservation. We source the Stuckelberg field using a
point particle with a slowly varying mass and show that two such particles feel
a constant attractive force. In this particular example, we see no Vainshtein
effect, and violations of the Equivalence Principle. The latter is probably
generic to other types of source and could potentially be used to place lower
bounds on the scale of Lorentz violation.Comment: 18 pages, 1 figure. Version to appear in JHEP. Conclusions with
respect to strong coupling modified - our strong coupling analysis does not
apply to a low scale of Lorentz violation. Expanded Equivalence Principle
violation discussion, noting it presents a challenge to low scale Lorentz
violation, exactly the scenario designed to cure strong coupling. Other minor
corrections and references adde
Smooth tensionful higher-codimensional brane worlds with bulk and brane form fields
Completely regular tensionful codimension-n brane world solutions are
discussed, where the core of the brane is chosen to be a thin codimension-(n-1)
shell in an infinite volume flat bulk, and an Einstein-Hilbert term localized
on the brane is included (Dvali-Gabadadze-Porrati models). In order to support
such localized sources we enrich the vacuum structure of the brane by the
inclusion of localized form fields. We find that phenomenological constraints
on the size of the internal core seem to impose an upper bound to the brane
tension. Finite transverse-volume smooth solutions are also discussed.Comment: 1+14 pages, 2 figures; section 2.3 improved, typos corrected and
references added. Published versio
Emergent gravity in spaces of constant curvature
In physical theories where the energy (action) is localized near a
submanifold of a constant curvature space, there is a universal expression for
the energy (or the action). We derive a multipole expansion for the energy that
has a finite number of terms, and depends on intrinsic geometric invariants of
the submanifold and extrinsic invariants of the embedding of the submanifold.
This is the second of a pair of articles in which we try to develop a theory of
emergent gravity arising from the embedding of a submanifold into an ambient
space equipped with a quantum field theory. Our theoretical method requires a
generalization of a formula due to by Hermann Weyl. While the first paper
discussed the framework in Euclidean (Minkowski) space, here we discuss how
this framework generalizes to spaces of constant sectional curvature. We focus
primarily on anti de Sitter space. We then discuss how such a theory can give
rise to a cosmological constant and Planck mass that are within reasonable
bounds of the experimental values.Comment: 20 pages, 3 figure
Gain and Loss Learning Differentially Contribute to Life Financial Outcomes
Emerging findings imply that distinct neurobehavioral systems process gains and losses. This study investigated whether individual differences in gain learning and loss learning might contribute to different life financial outcomes (i.e., assets versus debt). In a community sample of healthy adults (n = 75), rapid learners had smaller debt-to-asset ratios overall. More specific analyses, however, revealed that those who learned rapidly about gains had more assets, while those who learned rapidly about losses had less debt. These distinct associations remained strong even after controlling for potential cognitive (e.g., intelligence, memory, and risk preferences) and socioeconomic (e.g., age, sex, ethnicity, income, education) confounds. Self-reported measures of assets and debt were additionally validated with credit report data in a subset of subjects. These findings support the notion that different gain and loss learning systems may exert a cumulative influence on distinct life financial outcomes
Nonlinear Dynamics of 3D Massive Gravity
We explore the nonlinear classical dynamics of the three-dimensional theory
of "New Massive Gravity" proposed by Bergshoeff, Hohm and Townsend. We find
that the theory passes remarkably highly nontrivial consistency checks at the
nonlinear level. In particular, we show that: (1) In the decoupling limit of
the theory, the interactions of the helicity-0 mode are described by a single
cubic term -- the so-called cubic Galileon -- previously found in the context
of the DGP model and in certain 4D massive gravities. (2) The conformal mode of
the metric coincides with the helicity-0 mode in the decoupling limit. Away
from this limit the nonlinear dynamics of the former is described by a certain
generalization of Galileon interactions, which like the Galileons themselves
have a well-posed Cauchy problem. (3) We give a non-perturbative argument based
on the presence of additional symmetries that the full theory does not lead to
any extra degrees of freedom, suggesting that a 3D analog of the 4D
Boulware-Deser ghost is not present in this theory. Last but not least, we
generalize "New Massive Gravity" and construct a class of 3D cubic order
massive models that retain the above properties.Comment: 21 page
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