A person-centered approach to understanding negative reinforcement drinking among first year college students [post-print]

The current study used a person-centered approach (i.e. latent profile analysis) to identify distinct types of college student drinkers based on the predictions of motivational, social learning, and stress and coping theories of maladaptive drinking. A large sample (N = 844; 53% female) of first-year undergraduates from two institutions, public and private, who reported consuming one or more drinks in the last three months completed measures of depressive and anxiety symptoms, positive alcohol-outcome expectancies, negative life events, social support, drinking motives, drinking level and drinking-related problems. Latent profile analysis revealed a small subgroup of individuals (n = 81, 9%) who conformed to the anticipated high-risk profile; specifically, this group demonstrated high levels of negative affect, coping motives, drinks per week, and drinking-related problems. However, additional groups emerged that showed patterns inconsistent with the proposed vulnerability profile (e.g., high negative affect, positive expectancies, and negative life events, but relatively low drinking levels). Findings from our person-centered approach showing the presence of groups both consistent and inconsistent with the predictions of motivational, social learning, and stress and coping theories highlight the need to identify and target certain college students for prevention and intervention of negative affect-related drinking

Kohn–Sham energy decomposition for molecules in a magnetic field

We study the total molecular electronic energy and its Kohn–Sham components within the framework of magnetic-field density-functional theory (BDFT), an alternative to current-dependent density-functional theory (CDFT) for molecules in the presence of magnetic fields. For a selection of closed-shell dia- and paramagnetic molecules, we investigate the dependence of the total electronic energy and its Kohn–Sham components on the magnetic field. Results obtained from commonly used density-functional approximations are compared with those obtained from Lieb optimizations based on magnetic-field dependent relaxed coupled-cluster singles-and-doubles (CCSD) and second-order Møller–Plesset (MP2) densities. We show that popular approximate exchange–correlation functionals at the generalized-gradient-approximation (GGA), meta-GGA, and hybrid levels of theory provide a good qualitative description of the electronic energy and its Kohn–Sham components in a magnetic field—in particular, for the diamagnetic molecules. The performance of Hartree–Fock theory, MP2 theory, CCSD theory and BDFT with different exchange–correlation functionals is compared with coupled-cluster singles-doubles-perturbative-triples (CCSD(T)) theory for the perpendicular component of the magnetizability. Generalizations of the TPSS meta-GGA functional to systems in a magnetic field work well—the cTPSS functional, in particular, with a current-corrected kinetic-energy density, performs excellently, providing an accurate and balanced treatment of dia- and paramagnetic systems and outperforming MP2 theory

Sex differential in mortality trends of old-aged Danes: a nation wide study of age, period and cohort effects

Objective Over the last half century the mortality rates in Denmark for females above age 80 have declined dramatically whereas the decline for males have been modest, resulting in a change in sex-ratio for centenarians from 2 to 5. Here we investigate whether this mortality pattern is mainly explained by period effects, cohort effects or both. This can provide clues for where to search for causes behind the changes in sex differential in mortality seen in many Western countries during the last decades. Methods Age-period-cohort study of mortality for all Danish women and men aged 79–98 during the period 1949–2006. Outcome measures Relative risks for deaths and second order differences for exploration of the nonlinear variation. Results Both the overall trends in mortality differences and the fluctuations in mortality for both men and women were better explained by period effects than by cohort effects. The observed rates were better described by the age, period and cohort model than by other models. Conclusions Our results suggest that causes for both the overall increased difference in mortality and the short term fluctuations in mortality rates are primarily to be found in the period dimension. Cohort effects on the mortality of the oldest Danish women and men played a significant but minor role compared to period effects

Mouse Cognition-Related Behavior in the Open-Field: Emergence of Places of Attraction

Spatial memory is often studied in the Morris Water Maze, where the animal's spatial orientation has been shown to be mainly shaped by distal visual cues. Cognition-related behavior has also been described along “well-trodden paths”—spatial habits established by animals in the wild and in captivity reflecting a form of spatial memory. In the present study we combine the study of Open Field behavior with the study of behavior on well-trodden paths, revealing a form of locational memory that appears to correlate with spatial memory. The tracked path of the mouse is used to examine the dynamics of visiting behavior to locations. A visit is defined as either progressing through a location or stopping there, where progressing and stopping are computationally defined. We then estimate the probability of stopping at a location as a function of the number of previous visits to that location, i.e., we measure the effect of visiting history to a location on stopping in it. This can be regarded as an estimate of the familiarity of the mouse with locations. The recently wild-derived inbred strain CZECHII shows the highest effect of visiting history on stopping, C57 inbred mice show a lower effect, and DBA mice show no effect. We employ a rarely used, bottom-to-top computational approach, starting from simple kinematics of movement and gradually building our way up until we end with (emergent) locational memory. The effect of visiting history to a location on stopping in it can be regarded as an estimate of the familiarity of the mouse with locations, implying memory of these locations. We show that the magnitude of this estimate is strain-specific, implying a genetic influence. The dynamics of this process reveal that locations along the mouse's trodden path gradually become places of attraction, where the mouse stops habitually

Sexual dimorphism in cancer.

The incidence of many types of cancer arising in organs with non-reproductive functions is significantly higher in male populations than in female populations, with associated differences in survival. Occupational and/or behavioural factors are well-known underlying determinants. However, cellular and molecular differences between the two sexes are also likely to be important. In this Opinion article, we focus on the complex interplay that sex hormones and sex chromosomes can have in intrinsic control of cancer-initiating cell populations, the tumour microenvironment and systemic determinants of cancer development, such as the immune system and metabolism. A better appreciation of these differences between the two sexes could be of substantial value for cancer prevention as well as treatment

Helper Response to Experimentally Manipulated Predation Risk in the Cooperatively Breeding Cichlid Neolamprologus pulcher

Background We manipulated predation risk in a field experiment with the cooperatively breeding cichlid Neolamprologus pulcher by releasing no predator, a medium- or a large-sized fish predator inside underwater cages enclosing two to three natural groups. We assessed whether helpers changed their helping behaviour, and whether within-group conflict changed, depending on these treatments, testing three hypotheses: ‘pay-to-stay’ PS, ‘risk avoidance’ RA, or (future) reproductive benefits RB. We also assessed whether helper food intake was reduced under risk, because this might reduce investments in other behaviours to save energy. Methodology/Principal Findings Medium and large helpers fed less under predation risk. Despite this effect helpers invested more in territory defence, but not territory maintenance, under the risk of predation (supporting PS). Experimentally covering only the breeding shelter with sand induced more helper digging under predation risk compared to the control treatment (supporting PS). Aggression towards the introduced predator did not differ between the two predator treatments and increased with group member size and group size (supporting PS and RA). Large helpers increased their help ratio (helping effort/breeder aggression received, ‘punishment’ by the dominant pair in the group) in the predation treatments compared to the control treatment, suggesting they were more willing to PS. Medium helpers did not show such effects. Large helpers also showed a higher submission ratio (submission/ breeder aggression received) in all treatments, compared to the medium helpers (supporting PS). Conclusions/Significance We conclude that predation risk reduces helper food intake, but despite this effect, helpers were more willing to support the breeders, supporting PS. Effects of breeder punishment suggests that PS might be more important for large compared to the medium helpers. Evidence for RA was also detected. Finally, the results were inconsistent with RB