1,343 research outputs found
Post-learning Arousal Enhances Veridical Memory And Reduces False Memory In The Deese-Roediger-McDermott Paradigm
The Deese-Roediger-McDermott (DRM) paradigm examines false memory by introducing words associated with a non-presented ‘critical lure’ as memoranda, which typically causes the lures to be remembered as frequently as studied words. Our prior work has shown enhanced veridical memory and reduced misinformation effects when arousal is induced after learning (i.e., during memory consolidation). These effects have not been examined in the DRM task, or with signal detection analysis, which can elucidate the mechanisms underlying memory alterations. Thus, 130 subjects studied and then immediately recalled six DRM lists, one after another, and then watched a 3-min arousing (n = 61) or neutral (n = 69) video. Recognition tested 70 min later showed that arousal induced after learning led to better delayed discrimination of studied words from (a) critical lures, and (b) other non-presented ‘weak associates.’ Furthermore, arousal reduced liberal response bias (i.e., the tendency toward accepting dubious information) for studied words relative to all foils, including critical lures and ‘weak associates.’ Thus, arousal induced after learning effectively increased the distinction between signal and noise by enhancing access to verbatim information and reducing endorsement of dubious information. These findings provide important insights into the cognitive mechanisms by which arousal modulates early memory consolidation processes
Epoxy/ graphene nanocomposites – processing and properties: a review
Graphene has recently attracted significant academic and industrial interest because of its excellent performance in mechanical, electrical and thermal applications. Graphene can significantly improve physical properties of epoxy at extremely small loading when incorporated appropriately. Herein, the structure, preparation and properties of epoxy/graphene nanocomposites are reviewed in general, along with detailed examples drawn from the key scientific literature. The modification of graphene and the utilization of these materials in the fabrication of nanocomposites with different processing methods have been explored. This review has been focused on the processing methods and mechanical, electrical, thermal, and fire retardant properties of the nanocomposites. The synergic effects of graphene and other fillers in epoxy matrix have been summarised as well
A Review of Minority Stress as a Risk Factor for Cognitive Decline in Lesbian, Gay, Bisexual, and Transgender (LGBT) Elders
Lesbian, gay, bisexual, and transgender (LGBT) older adults comprise a unique and growing subset of the aging population. The historical context in which they came of age was imbued with victimization and discrimination. These experiences are subjectively stressful and collectively known as minority stress. Older LGBT adults continue to face stressors related to their gender and sexual identities in their daily lives. Importantly, chronic minority stress (CMS), like other forms of chronic stress, is harmful to health and well-being. CMS contributes to LGBT health disparities, including cardiovascular disease and depression, conditions that in turn increase risk for premature cognitive decline. Furthermore, long-term exposure to stress hormones is associated with accelerated brain aging. Yet, the cognitive functioning of LGBT elders and the influence of CMS on their cognition is all but unexplored. In this review, we examine the influences of CMS in LGBT elders and connect those influences to existing research on stress and cognitive aging. We propose a testable model describing how CMS in LGBT elders heightens risk for premature cognitive aging and how ameliorating factors may help protect from CMS risk. Research is desperately needed to calibrate this model toward improving LGBT quality of life and mental health practices
An exploratory aerodynamic and structural investigation of all-flexible parawings
Aerodynamic and structural aspects of all-flexible parawing
Disorder, spin-orbit, and interaction effects in dilute
We derive an effective Hamiltonian for in
the dilute limit, where can be described in
terms of spin polarons hopping between the {\rm Mn} sites and coupled
to the local {\rm Mn} spins. We determine the parameters of our model from
microscopic calculations using both a variational method and an exact
diagonalization within the so-called spherical approximation. Our approach
treats the extremely large Coulomb interaction in a non-perturbative way, and
captures the effects of strong spin-orbit coupling and Mn positional disorder.
We study the effective Hamiltonian in a mean field and variational calculation,
including the effects of interactions between the holes at both zero and finite
temperature. We study the resulting magnetic properties, such as the
magnetization and spin disorder manifest in the generically non-collinear
magnetic state. We find a well formed impurity band fairly well separated from
the valence band up to for which finite size
scaling studies of the participation ratios indicate a localization transition,
even in the presence of strong on-site interactions, where is the fraction of magnetically active Mn. We study the
localization transition as a function of hole concentration, Mn positional
disorder, and interaction strength between the holes.Comment: 15 pages, 12 figure
Positional Disorder, Spin-Orbit Coupling and Frustration in GaMnAs
We study the magnetic properties of metallic GaMnAs. We calculate the
effective RKKY interaction between Mn spins using several realistic models for
the valence band structure of GaAs. We also study the effect of positional
disorder of the Mn on the magnetic properties. We find that the interaction
between two Mn spins is anisotropic due to spin-orbit coupling within both the
so-called spherical approximation and in the more realistic six band model. The
spherical approximation strongly overestimates this anistropy, especially for
short distances between Mn ions. Using the obtained effective Hamiltonian we
carry out Monte Carlo simulations of finite and zero temperature magnetization
and find that, due to orientational frustration of the spins, non-collinear
states appear in both valence band approximations for disordered, uncorrelated
Mn impurities in the small concentration regime. Introducing correlations among
the substitutional Mn positions or increasing the Mn concentration leads to an
increase in the remnant magnetization at zero temperature and an almost fully
polarized ferromagnetic state.Comment: 17 Pages, 13 Figure
The Role of Alexithymia in Memory and Executive Functioning Across the Lifespan
Alexithymia is a personality trait characterised by difficulties identifying feelings (DIF), describing feelings (DDF), and externally oriented thinking (EOT). Alexithymia has been associated with poorer memory, at least for emotive materials, and recently, with executive and neural dysfunction. Aging is also accompanied by poorer memory and executive functioning (EF), neural dysfunction, and increasing alexithymia. Thus, the hypothesis of a general cognitive impairment in alexithymia, particularly in elders, needs investigation. Three large, independent, cross-sectional experiments (n = 296, 139 and 121, respectively) investigated memory and EF in healthy adults, ranging from young to old adulthood, with age, sex, and the three Toronto Alexithymia Scale-20 subscales (DIF, DDF, EOT) as predictors in hierarchical regressions. Across studies, alexithymia contributed to poorer memory (via EOT) and EF (via DIF), in younger and older adults. Additionally, these effects occurred in non-emotive contexts with neutral stimuli. Moreover, although memory was worse with greater age and poor EF contributed to poor memory, those who had both high EOT and poor EF had particularly poor memory. Thus, alexithymia (particularly via high DIF or high EOT) is a risk factor for age-related cognitive decline. Further research should clarify the direction and nature of these complex relationships
Orbits of quantum states and geometry of Bloch vectors for -level systems
Physical constraints such as positivity endow the set of quantum states with
a rich geometry if the system dimension is greater than two. To shed some light
on the complicated structure of the set of quantum states, we consider a
stratification with strata given by unitary orbit manifolds, which can be
identified with flag manifolds. The results are applied to study the geometry
of the coherence vector for n-level quantum systems. It is shown that the
unitary orbits can be naturally identified with spheres in R^{n^2-1} only for
n=2. In higher dimensions the coherence vector only defines a non-surjective
embedding into a closed ball. A detailed analysis of the three-level case is
presented. Finally, a refined stratification in terms of symplectic orbits is
considered.Comment: 15 pages LaTeX, 3 figures, reformatted, slightly modified version,
corrected eq.(3), to appear in J. Physics
Probabilistic abstract interpretation: From trace semantics to DTMC’s and linear regression
In order to perform probabilistic program analysis we need to consider probabilistic languages or languages with a probabilistic semantics, as well as a corresponding framework for the analysis which is able to accommodate probabilistic properties and properties of probabilistic computations. To this purpose we investigate the relationship between three different types of probabilistic semantics for a core imperative language, namely Kozen’s Fixpoint Semantics, our Linear Operator Semantics and probabilistic versions of Maximal Trace Semantics. We also discuss the relationship between Probabilistic Abstract Interpretation (PAI) and statistical or linear regression analysis. While classical Abstract Interpretation, based on Galois connection, allows only for worst-case analyses, the use of the Moore-Penrose pseudo inverse in PAI opens the possibility of exploiting statistical and noisy observations in order to analyse and identify various system properties
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