Negative Recurrent Thinking as a Moderator of the Relationship Between Perceived Stress and Depressive Symptoms

Both perceived stress and negative recurrent thinking (rumination and worry) have been associated with depressive symptoms. However, no research to date has investigated the association between perceived stress and negative recurrent thinking. In the present study we aimed to explore whether perceived stress and negative recurrent thinking are associated and whether negative recurrent thinking moderates the relationship between perceived stress and depressive symptoms. A convenience sample of 273 undergraduate students completed the Perceived Stress Scale, the Ruminative Responses Scale-10, the Penn State Worry Questionnaire and the Hospital Anxiety and Depression Scale 2 weeks prior to sitting mid-year examinations. Correlation analyses showed that perceived stress, rumination and worry were positively and significantly associated with depressive symptoms and that perceived stress was positively and significantly associated with rumination and worry. A moderation analysis confirmed that negative recurrent thinking moderated the relationship between perceived stress and depressive symptoms. The implications of these findings are discussed.     

Sexting as a predictor of sexual behavior in a sample of Czech adolescents

The purpose of this longitudinal study is to examine the relationship between teen sexting and offline sexual behavior. Using a sample of 1134 Czech adolescents aged 10–18 (M_age = 13.84, SD = 1.94, girls = 58.8%) from 55 schools, the latent growth model of offline sexual behavior with sexting as a time-varying covariate was employed. Participants differed at baseline for offline sexual behavior at both individual and school levels, and they varied in the growth rate of offline sexual behavior at the individual level. Only age and sensation seeking explained the variability at baseline of offline sexual behavior. The positive association between sexting and offline sexual behavior was not constant across time. However, sexting at baseline predicted offline sexual behavior a half year and one year later. Sexting may be treated as a precursor of offline sexual behavior.     

Variation with density of the transport properties of YBaCuO superconductors

Abstract

The dependence of the normal-state resistivity, resistive superconducting transition (T _c, ΔT _c), and of the upper critical-field slope (dH _c2/dT|T=T_c) on density has been investigated for several YBa₂Cu₃O_9-x(x?2.1) samples. The resistivity decreases rapidly with increasing density, whereas T _c and ΔT _c are rather insensitive to a change in density. dH _c2/dT|T_c depends sensitively on the preparation conditions. The implications of these results both for the evaluation of the parameters relevant to the understanding of the nature of superconductivity and for the technological applications of granular superconductors are briefly discussed.     

A Note on Bisimulation and Modal Equivalence in Provability Logic and Interpretability Logic

Provability logic is a modal logic for studying properties of provability predicates, and Interpretability logic for studying interpretability between logical theories. Their natural models are GL-models and Veltman models, for which the accessibility relation is well-founded. That’s why the usual counterexample showing the necessity of finite image property in Hennessy-Milner theorem (see [1]) doesn’t exist for them. However, we show that the analogous condition must still hold, by constructing two GL-models with worlds in them that are modally equivalent but not bisimilar, and showing how these GL-models can be converted to Veltman models with the same properties. In the process we develop some useful constructions: games on Veltman models, chains, and general method of transformation from GL-models/frames to Veltman ones.     

The Self-Knowledge Gambit

If we hold that perceiving is sufficient for knowing, we can raise a powerful objection to dreaming skepticism: Skeptics assume the implausible KK-principle, because they hold that if we don’t know whether we are dreaming or perceiving p, we don’t know whether p. The rejection of the KK-principle thus suggests an anti-skeptical strategy: We can sacrifice some of our self-knowledge—our second-order knowledge—and thereby save our knowledge of the external world. I call this strategy the Self-Knowledge Gambit. I argue that the Self-Knowledge Gambit is not satisfactory, because the dreaming skeptic can avail herself of a normative counterpart to the KK-principle: When we lack second-order knowledge, we should suspend our first-order beliefs and thereby give up any first-order knowledge we might have had. The skeptical challenge is essentially a normative challenge, and one can raise it even if one rejects the KK-Principle.     

Visual image retention does not contribute to modulation of event-related potentials by mental rotation

Rotation of a visual image in mind is associated with a slow posterior negative deflection of the event-related potential (ERP), termed rotation-related negativity (RRN). Retention of a visual image in short-term memory is also associated with a slow posterior negative ERP, termed negative slow wave (NSW). We tested whether short-term memory retention, indexed by the NSW, contributes to the RRN. ERPs were recorded in the same subjects in two tasks, a mental rotation task, eliciting the RRN, and a visual short-term memory task, eliciting the NSW. Over both right and left parietal scalp, no association was found between the NSW and the RRN amplitudes. Furthermore, adjusting for the effect of the NSW had no influence on a significant association between the RRN amplitude and response time, an index of mental rotation performance. Our data indicate that the RRN reflects manipulation of a visual image but not its retention in short-term memory.     

Exact solution of the one-dimensional Potts bridge model with competing interactions

Abstract

The exact solution of the q-state Potts bridge model with competing ferromagnetic and antiferromagnetic interactions is obtained and corresponding regular and critical behaviour studied.