9,444 research outputs found
Motor action and emotional memory
Can simple motor actions affect how efficiently people retrieve emotional memories, and influence what they choose to remember? In Experiment 1, participants were prompted to retell autobiographical memories with either positive or negative valence, while moving marbles either upward or downward. They retrieved memories faster when the direction of movement was congruent with the valence of the memory (upward for positive, downward for negative memories). Given neutral-valence prompts in Experiment 2, participants retrieved more positive memories when instructed to move marbles up, and more negative memories when instructed to move them down, demonstrating a causal link from motion to emotion. Results suggest that positive and negative life experiences are implicitly associated with schematic representations of upward and downward motion, consistent with theories of metaphorical mental representation. Beyond influencing the efficiency of memory retrieval, the direction of irrelevant, repetitive motor actions can also partly determine the emotional content of the memories people retrieve: moving marbles upward (an ostensibly meaningless action) can cause people to think more positive thoughts
On the relation between adjacent inviscid cell type solutions to the rotating-disk equations
Over a large range of the axial coordinate a typical higher-branch solution of the rotating-disk equations consists of a chain of inviscid cells separated from each other by viscous interlayers. In this paper the leading-order relation between two adjacent cells will be established by matched asymptotic expansions for general values of the parameter appearing in the equations. It is found that the relation between the solutions in the two cells crucially depends on the behaviour of the tangential velocity in the viscous interlayer. The results of the theory are compared with accurate numerical solutions and good agreement is obtained
Mixing the stimulus list in bilingual lexical decision turns cognate facilitation effects into mirrored inhibition effects
To test the BIA+ and Multilink modelsâ accounts of how bilinguals process words with different degrees of cross-linguistic orthographic and semantic overlap, we conducted two experiments manipulating stimulus list composition. Dutch-English late bilinguals performed two English lexical decision tasks including the same set of cognates, interlingual homographs, English control words, and pseudowords. In one task, half of the pseudowords were replaced with Dutch words, requiring a ânoâ response. This change from pure to mixed language list context was found to turn cognate facilitation effects into inhibition. Relative to control words, larger effects were found for cognate pairs with an increasing cross-linguistic form overlap. Identical cognates produced considerably larger effects than non-identical cognates, supporting their special status in the bilingual lexicon. Response patterns for different item types are accounted for in terms of the itemsâ lexical representation and their binding to âyesâ and ânoâ responses in pure vs mixed lexical decision
Stabilizing the Hexagonal Close Packed Structure of Hard Spheres with Polymers : Phase diagram, Structure, and Dynamics
We study the phase behaviour of a binary mixture of colloidal hard spheres
and freely-jointed chains of beads using Monte Carlo simulations. Recently
Panagiotopoulos and coworkers predicted [Nat. Commun. 5, 4472 (2014)] that the
hexagonal close packed (HCP) structure of hard spheres can be stabilized in
such a mixture due to the interplay between polymer and the void structure in
the crystal phase. Their predictions were based on estimates of the free-energy
penalty for adding a single hard polymer chain in the HCP and the competing
face centered cubic (FCC) phase. Here we calculate the phase diagram using
free-energy calculations of the full binary mixture and find a broad
fluid-solid coexistence region and a metastable gas-liquid coexistence region.
For the colloid-monomer size ratio considered in this work, we find that the
HCP phase is only stable in a small window at relatively high polymer reservoir
packing fractions, where the coexisting HCP phase is nearly close packed.
Additionally we investigate the structure and dynamic behaviour of these
mixtures.Comment: 8 pages, 5 figure
A continued fraction expansion for a generalization of Dawson's integral
A continued fraction expansion for a generalization of Dawson's integral is presented. An exact formula for the truncation error in terms of the confluent hypergeometric function is derived. The expansion is shown to have good convergence properties for both small and large values of the argument
Dynamical Heterogeneities and Cooperative Motion in Smectic Liquid Crystals
Using simulations of hard rods in smectic-A states, we find non-gaussian
diffusion and heterogeneous dynamics due to the equilibrium periodic smectic
density profiles, which give rise to permanent barriers for layer-to-layer
diffusion. This relaxation behavior is surprisingly similar to that of
non-equilibrium supercooled liquids, although there the particles are trapped
in transient (instead of permanent) cages. Interestingly, we also find
stringlike clusters of up to 10 inter-layer rods exhibiting dynamic
cooperativity in this equilibrium state.Comment: 10 pages, 4 figure
Heterogeneous Dynamics in Columnar Liquid Crystals of Parallel Hard Rods
In the wake of previous studies on the rattling-and-jumping diffusion in
smectic liquid crystal phases of colloidal rods, we analyze here for the first
time the heterogeneous dynamics in columnar phases. More specifically, we
perform computer simulations to investigate the relaxation dynamics of a binary
mixture of perfectly aligned hard spherocylinders. We detect that the columnar
arrangement of the system produces free-energy barriers the particles should
overcome to jump from one column to another, thus determining a hopping-type
diffusion. This phenomenon accounts for the non-Gaussian inter-column diffusion
and shows a two-step structural relaxation which is remarkably analogous to
that of out-of-equilibrium glass-forming systems and gels. Surprisingly enough,
slight deviations from the behavior of simple liquids due to transient cages is
also observed in the direction perpendicular to this plane, where the system is
usually referred to as liquid-like.Comment: accepted by J Chem Phys; 10 pages, 10 figure
Ruelle-Pollicott Resonances of Stochastic Systems in Reduced State Space. Part II: Stochastic Hopf Bifurcation
The spectrum of the generator (Kolmogorov operator) of a diffusion process,
referred to as the Ruelle-Pollicott (RP) spectrum, provides a detailed
characterization of correlation functions and power spectra of stochastic
systems via decomposition formulas in terms of RP resonances. Stochastic
analysis techniques relying on the theory of Markov semigroups for the study of
the RP spectrum and a rigorous reduction method is presented in Part I. This
framework is here applied to study a stochastic Hopf bifurcation in view of
characterizing the statistical properties of nonlinear oscillators perturbed by
noise, depending on their stability. In light of the H\"ormander theorem, it is
first shown that the geometry of the unperturbed limit cycle, in particular its
isochrons, is essential to understand the effect of noise and the phenomenon of
phase diffusion. In addition, it is shown that the spectrum has a spectral gap,
even at the bifurcation point, and that correlations decay exponentially fast.
Explicit small-noise expansions of the RP eigenvalues and eigenfunctions are
then obtained, away from the bifurcation point, based on the knowledge of the
linearized deterministic dynamics and the characteristics of the noise. These
formulas allow one to understand how the interaction of the noise with the
deterministic dynamics affect the decay of correlations. Numerical results
complement the study of the RP spectrum at the bifurcation, revealing useful
scaling laws. The analysis of the Markov semigroup for stochastic bifurcations
is thus promising in providing a complementary approach to the more geometric
random dynamical system approach. This approach is not limited to
low-dimensional systems and the reduction method presented in part I is applied
to a stochastic model relevant to climate dynamics in part III
Calculations on the current density and the voltage-current relation under a.c. conditions of filaments
Technical applications of multifilamentary wires indicate that filaments are used in complex magnetic fields (a combination of non-parallel a.c./d.c. transverse and rotating fields) carrying an a.c./d.c. transport current of various frequency. Furthermore, due to technical manufacturing processes the filaments are heavily distorted. Therefore, a numerical model is developed to compute the current density of a filament of arbitrary shape in any external transverse field carrying an a.c./d.c. transport current. The great flexibility of the model is shown in several examples
Towards agent-based crowd simulation in airports using games technology
We adapt popular video games technology for an agent-based crowd simulation in an airport terminal. To achieve this, we investigate the unique traits of airports and implement a virtual crowd by exploiting a scalable layered intelligence technique in combination with physics middleware and a socialforces approach. Our experiments show that the framework runs at interactive frame-rate and evaluate the scalability with increasing number of agents demonstrating
navigation behaviour
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