2,617 research outputs found
A new modelling framework for statistical cumulus dynamics
We propose a new modelling framework suitable for the description of atmospheric convective systems as a collection of distinct plumes. The literature contains many examples of models for collections of plumes in which strong simplifying assumptions are made, a diagnostic dependence of convection on the large-scale environment and the limit of many plumes often being imposed from the outset. Some recent studies have sought to remove one or the other of those assumptions. The proposed framework removes both, and is explicitly time-dependent and stochastic in its basic character. The statistical dynamics of the plume collection are defined through simple probabilistic rules applied at the level of individual plumes, and van Kampen's system size expansion is then used to construct the macroscopic limit of the microscopic model. Through suitable choices of the microscopic rules, the model is shown to encompass previous studies in the appropriate limits, and to allow their natural extensions beyond those limits
The Dutch DAPP-BQ: improvements, lower- and higher-order dimensions, and relationship with the 5DPT.
Jackson, 2002), the present DAPP-BQ scales (with or without Self-Harm included) were subjected to a principal components analysis with oblimin or varimax rotation in a general population sample of 478 subjects, retaining four factors. All four (higherorder) factors (Emotional Dysregulation, Dissocial, Inhibition, and Compulsivity) proved identical to the factors originally derived in Canada, with Tucker coefficients of factor similarity approaching unity. Particularly the (unexpected) finding that the present Dutch version of the DAPP-BQ also resulted in an Inhibition factor (and not, like the former Dutch version, in an Intimacy Problems factor) was considered positive. In addition, a principal components analysis with oblimin rotation was conducted on the 282 items contained in the 18 DAPP-BQ scales, investigating the lower-order structure of the DAPP-BQ; in this case, 18 factors were retained. Although the structure originally derived by Livesley and colleagues could not be recovered completely, the degree of similarity was of such a magnitude that the 18 DAPP-BQ scales were considered to give a dependable account of the “true” lower-order structure of disordered personality. Moreover, based on the finding that the 18 scales are sufficiently reliable (Cronbach's alpha) and correlate as predicted in a subsample of 284 subjects with the normal personality scales of Van Kampen's 5DPT (or, Five-Dimensional Personality Test), the DAPP-BQ appears to be a valuable instrument
Genetic and Environmental Influences on Pre-schizophrenic personality: MAXCOV-HITMAX and LISREL Analyses.
Postulating that the predisposition to illness in Claridge's disease model of schizophrenia can be equated with the personality dimensions S or Insensitivity, (low) E or Extraversion, and N or Neuroticism, as measured by Van Kampen's 3DPT, and assuming that the mode of transmission of schizophrenia is basically polygenic, the genetic and environmental etiology of S, E, and N was assessed in a sample of 52 MZ and 76 DZ twin pairs and their parents by means of LISREL. Besides, in a sample of 2118 subjects MAXCOV–HITMAX analyses were conducted for these factors as well as for the personality dimension G or Orderliness, but now assessed by the 4DPT, in order to find out whether a discrete or quasi-discrete variable might also underlie these dimensions, giving support to the possibility of dominance or epistasis. The results obtained in these investigations favoured a model for all three dimensions, allowing for both additive and non-additive genetic effects in combination with non-shared environmental influences. It was not possible to choose between a model involving dominance and a model involving epistatic genetic effects. With the use of scores corrected for sex and age, which were converted to normal scores, the proportion of variance explained by additive genetic factors was 20% for S, 40–41% for E, and 26–29% for N. Dominance or multiple-gene epistasis accounted for 37–38% (S), 19–20% (E), and 30–31% (N), and unshared environmental influences for 42–43% (S), 41% (E), and 42–43% (N) respectively
The 5-Dimensional Personality Test (5DPT): Relationships with Two Lexically Based Instruments and the Validation of the Absorption Scale
Although intended to assess vulnerability factors associated with psychopathology, the 5-Dimensional Personality Test (5DPT) shows at least a superficial similarity to instruments that adhere to the lexical tradition in personality psychology. To investigate to which extent this similarity goes, this article compares the 5DPT with 2 lexically based measures, the NEO-Five Factor Inventory and the HEXACO-Personality Inventory-Revised. Moreover, as the NEO Openness to Experience construct demonstrates little relationship with maladaptive personality, whereas the 5DPT Absorption factor was hypothesized to underlie the emergence of positive schizotypic symptoms and related phenomena, the 5DPT was also correlated with the Schizotypic Syndrome Questionnaire (SSQ), the Creative Experiences Questionnaire, Thalbourne's Transliminality Scale, the Launay-Slade Hallucination Scale, and the OLIFE-Unusual Experiences scale. On examining the correlations between the various instruments, it was ascertained (a) that there is no need to extend the theory-informed 5DPT with a 6th dimension similar to the HEXACO factor Honesty-Humility, (b) that the 5DPT dimensions were found on average to share only a moderate amount of variance with the Five-factor model/Big Five factors, and (c) that the 5DPT Absorption scale turned out as anticipated to correlate with the positive symptom scales of the SSQ, as well as with the remaining criterion scales that measure similar constructs. © 2012 Copyright Taylor and Francis Group, LLC
Analytical results for a Fokker-Planck equation in the small noise limit
We present analytical results for the lowest cumulants of a stochastic
process described by a Fokker-Planck equation with nonlinear drift. We show
that, in the limit of small fluctuations, the mean, the variance and the
covariance of the process can be expressed in compact form with the help of the
Lambert W function. As an application, we discuss the interplay of noise and
nonlinearity far from equilibrium.Comment: 5 pages, 4 figure
Slow transport by continuous time quantum walks
Continuous time quantum walks (CTQW) do not necessarily perform better than
their classical counterparts, the continuous time random walks (CTRW). For one
special graph, where a recent analysis showed that in a particular direction of
propagation the penetration of the graph is faster by CTQWs than by CTRWs, we
demonstrate that in another direction of propagation the opposite is true; In
this case a CTQW initially localized at one site displays a slow transport. We
furthermore show that when the CTQW's initial condition is a totally symmetric
superposition of states of equivalent sites, the transport gets to be much more
rapid.Comment: 5 pages, 7 figures, accepted for publication in Phys. Rev.
Anderson localization as a parametric instability of the linear kicked oscillator
We rigorously analyse the correspondence between the one-dimensional standard
Anderson model and a related classical system, the `kicked oscillator' with
noisy frequency. We show that the Anderson localization corresponds to a
parametric instability of the oscillator, with the localization length
determined by an increment of the exponential growth of the energy. Analytical
expression for a weak disorder is obtained, which is valid both inside the
energy band and at the band edge.Comment: 7 pages, Revtex, no figures, submitted to Phys. Rev.
Compaction and tensile forces determine the accuracy of folding landscape parameters from single molecule pulling experiments
We establish a framework for assessing whether the transition state location
of a biopolymer, which can be inferred from single molecule pulling
experiments, corresponds to the ensemble of structures that have equal
probability of reaching either the folded or unfolded states (Pfold = 0.5).
Using results for the forced-unfolding of a RNA hairpin, an exactly soluble
model and an analytic theory, we show that Pfold is solely determined by s, an
experimentally measurable molecular tensegrity parameter, which is a ratio of
the tensile force and a compaction force that stabilizes the folded state.
Applications to folding landscapes of DNA hairpins and leucine zipper with two
barriers provide a structural interpretation of single molecule experimental
data. Our theory can be used to assess whether molecular extension is a good
reaction coordinate using measured free energy profiles.Comment: 6 pages, 4 figures, Phys. Rev. Lett. (in press
The Hexaco and 5DPT models of personality: a comparison and their relationships with psychopathy, egoism, pretentiousness, immorality and machaivallianism.
This study describes and tests two models of personality: the HEXACO model of personality, which is derived from the lexical tradition and which is rooted In "normal" psychology, and the 5DPT model of personality, which is derived from a theoretical approach and which is rooted in clinical psychology. The HEXACO and 5DPT models are compared In the prediction of antisocial and self-benefiting personality traits in a large-scale community sample study. Relative weight analyses show that HEXACO Honesty-Humility explains most of the variance in SRP-III Psychopathy, Egoism, and IPIP Pretentiousness, Immorality, and Machiavellianism. Additionally, Honesty-Humility is able to Increment the amount of variance explained by the 5DPT scales in these antisocial and self-benefiting personality scales. Consequences for the 5DPT and for the choice of a dimensional axis-II personality model in the run-up of the DSM-V are discussed. © 2010 The Guilford Press
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