The double competition number of some triangle-free graphs

AbstractThe competition graph of a digraph was introduced by Joel Cohen in 1968 in the study of ecological niches. It was generalized by Debra Scott in 1985 to the competition-common enemy graph. In this paper, we study some triangle-free competition-common enemy graphs

Two centuries of trend following

We establish the existence of anomalous excess returns based on trend following strategies across four asset classes (commodities, currencies, stock indices, bonds) and over very long time scales. We use for our studies both futures time series, that exist since 1960, and spot time series that allow us to go back to 1800 on commodities and indices. The overall t-stat of the excess returns is $\approx 5$ since 1960 and $\approx 10$ since 1800, after accounting for the overall upward drift of these markets. The effect is very stable, both across time and asset classes. It makes the existence of trends one of the most statistically significant anomalies in financial markets. When analyzing the trend following signal further, we find a clear saturation effect for large signals, suggesting that fundamentalist traders do not attempt to resist "weak trends", but step in when their own signal becomes strong enough. Finally, we study the performance of trend following in the recent period. We find no sign of a statistical degradation of long trends, whereas shorter trends have significantly withered.Comment: 17 pages, 9 figures, 9 table

Changing Face of the Extrasolar Giant Planet, HD 209458b

High-resolution atmospheric flow simulations of the tidally-locked extrasolar giant planet, HD 209458b, show large-scale spatio-temporal variability. This is in contrast to the simple, permanent day/night (i.e., hot/cold) picture. The planet's global circulation is characterized by a polar vortex in motion around each pole and a banded structure corresponding to ~3 broad zonal (east-west) jets. For very strong jets, the circulation-induced temperature difference between moving hot and cold regions can reach up to ~1000 K, suggesting that atmospheric variability could be observed in the planet's spectral and photometric signatures.Comment: 6 pages, 1 ps figure, 2 low-res color figures (JPEG). Figure 3 updated. Contact authors for hi-res versions of color figures. Accepted for publication in ApJ

Gender differences in the association between attachment style and adulthood relationship satisfaction (brief report)

In general, the quality of the caregiver-child attachment formed in early childhood will influence the quality of relationships in adulthood. Our survey of 217 adults aimed to assess to what extent relationship satisfaction in adults is accounted for by attachment style. After controlling for demographic variables, we found that an increase in attachment problems predicted a reduction in adulthood relationship satisfaction. The effect of attachment on adulthood relationships was stronger in women than men for avoidant attachment (β = -5.67, p < .00000005, and β = -4.60, p <.001 respectively), and weaker for women than men for anxious attachment (β = -2.21, p < .05, and β = -4.33, p <.01 respectively). Implications for child rearing and adult therapy are discussed

The Male Psychology Conference, University College London, June 2014

The Male Psychology conference is taking place at University College, London, on June 20th 2014. This article describes the context of the conference, for example, the reasons why it is necessary and the types of challenges facing men and boys today. Conference presentations will span the topics of: suicide and male help-seeking behaviour, improving therapy for men, steroid use, empathy, emotional intelligence, and the perennial topic of masculinity. Abstracts of the presentations are in the appendix of this article. The conference will have keynote speeches from highly respected speakers on the subjects of government policy on men’s psychological needs (David Wilkins), sexual misconduct (Professor Andrew Samuels), and getting beyond notions like ‘manning up’ (Glen Poole). There will also be poetry readings straight from the heart of Rob Mackerill, and posters on subjects ranging from male asylum seekers to The Sopranos. It is hoped that this conference – the first Male Psychology conference – will improve awareness of the importance of this area to psychologists and others. Full details of the conference can be found here http://www.malepsychology.org.uk/index.html

Binning is sinning: morphological light-curve distortions due to finite integration time

We explore how finite integration times or equivalently temporal binning induces morphological distortions to the transit light-curve. These distortions, if uncorrected for, lead to the retrieval of erroneous system parameters and may even lead to some planetary candidates being rejected as ostensibly unphysical. We provide analytic expressions for estimating the disturbance to the various light-curve parameters as a function of the integration time. These effects are particularly crucial in light of the long-cadence photometry often used for discovering new exoplanets by, for example, Convection Rotation and Planetary Transits (COROT) and the Kepler Mission (8.5 and 30 min). One of the dominant effects of long integration times is a systematic underestimation of the light-curve-derived stellar density, which has significant ramifications for transit surveys. We present a discussion of numerical integration techniques to compensate for the effects and produce expressions to quickly estimate the errors of such techniques, as a function of integration time and numerical resolution. This allows for an economic choice of resolution before attempting fits of long-cadence light-curves. We provide a comparison of the short- and long-cadence light-curves of TrES-2b and show that the retrieved transit parameters are consistent using the techniques discussed here.Comment: Long delayed upload of the MNRAS accepted version, 10 pages, 3 figure

Gender-Related Schemas and Suicidality: Validation of the Male and Female Traditional Gender Scripts Questionnaires

Background: The issue of whether gender-related attitudes underlie the sex difference in suicide has been relatively unexplored. This study sought to validate questionnaires measuring traditional male and female gender scripts in order to test the hypothesis that scores on these questionnaires predict suicidality. Methods: The responses of 348 women and 170 men were analysed using factor analysis and hierarchical multiple regression. Results: After controlling for other variables, two male gender subscales predicted risk of suicidality (Fight & Win, P<.001; Mastery & Control, P<.042), and one female gender subscale predicted reduced risk of suicidality (Family Harmony, P<.003). Conclusions: These novel findings have implications for understanding and predicting suicidality in men and women, and may be valuable in the clinical context

Are clinical psychologists, psychotherapists and counsellors overlooking the needs of their male clients?

Around 75 per cent of suicides are male, yet men seek therapy less than women do. Is talking about feelings unappealing to men? Our interviews with 20 experienced therapists identified ways in which therapy might be made more male-friendly