B-type supergiants in the Small Magellanic Cloud: rotational velocities and implications for evolutionary models

High-resolution spectra for 24 SMC and Galactic B-type supergiants have been analysed to estimate the contributions of both macroturbulence and rotation to the broadening of their metal lines. Two different methodologies are considered, viz. goodness-of-fit comparisons between observed and theoretical line profiles and identifying zeros in the Fourier transforms of the observed profiles. The advantages and limitations of the two methods are briefly discussed with the latter techniques being adopted for estimating projected rotational velocities ( v sin i) but the former being used to estimate macroturbulent velocities. The projected rotational velocity estimates range from approximately 20 to 60 kms(-1), apart from one SMC supergiant, Sk 191, with a v sin i similar or equal to 90 km s(-1). Apart from Sk 191, the distribution of projected rotational velocities as a function of spectral type are similar in both our Galactic and SMC samples with larger values being found at earlier spectral types. There is marginal evidence for the projected rotational velocities in the SMC being higher than those in the Galactic targets but any differences are only of the order of 5 - 10 km s(-1), whilst evolutionary models predict differences in this effective temperature range of typically 20 to 70 km s(-1). The combined sample is consistent with a linear variation of projected rotational velocity with effective temperature, which would imply rotational velocities for supergiants of 70 kms(-1) at an effective temperature of 28 000 K ( approximately B0 spectral type) decreasing to 32 km s(-1) at 12 000 K (B8 spectral type). For all targets, the macroturbulent broadening would appear to be consistent with a Gaussian distribution ( although other distributions cannot be discounted) with an 1/e half-width varying from approximately 20 km s(-1) at B8 to 60 km s(-1) at B0 spectral types.

Epipolar geometry estimation based on evolutionary agents

This paper presents a novel approach based on the use of evolutionary agents for epipolar geometry estimation. In contrast to conventional nonlinear optimization methods, the proposed technique employs each agent to denote a minimal subset to compute the fundamental matrix, and considers the data set of correspondences as a 1D cellular environment, in which the agents inhabit and evolve. The agents execute some evolutionary behavior, and evolve autonomously in a vast solution space to reach the optimal (or near optima) result. Then three different techniques are proposed in order to improve the searching ability and computational efficiency of the original agents. Subset template enables agents to collaborate more efficiently with each other, and inherit accurate information from the whole agent set. Competitive evolutionary agent (CEA) and finite multiple evolutionary agent (FMEA) apply a better evolutionary strategy or decision rule, and focus on different aspects of the evolutionary process. Experimental results with both synthetic data and real images show that the proposed agent-based approaches perform better than other typical methods in terms of accuracy and speed, and are more robust to noise and outliers.

The structure of the Statistics Anxiety Rating Scale: A confirmatory factor analysis using UK psychology students

This study aimed to examine the structure of the statistics anxiety rating scale. Responses from 650 undergraduate psychology students throughout the UK were collected through an on-line study. Based on previous research three different models were specified and estimated using confirmatory factor analysis. Fit indices were used to determine if the model fitted the data and a likelihood ratio difference test was used to determine the best fitting model. The original six factor model was the best explanation of the data. All six subscales were intercorrelated and internally consistent. It was concluded that the statistics anxiety rating scale was found to measure the six subscales it was designed to assess in a UK population.

Common psychology problems in cerebral palsy

Cerebral palsy (CP) refers to a collection of motor impairments which result in abnormal posture and movement following an insult or damage to the developing brain. Psychological adjustment in children with CP is under researched with little population-based or longitudinal data, but there is sufficient evidence to suggest that children with CP are at increased risk for psychological problems. The types of difficulties they experience include emotional, hyperactivity and peer problems with conduct disorder being more prevalent in mildly affected children. The origins of psychological problems in this group are complex but include ‘disease’ and ‘psychosocial’ factors related to having a brain-based disability in the family, as well as other factors that influence adjustment in all children. There are no intervention studies in children with CP aimed at preventing psychological problems or promoting mental wellbeing. However, evidence from other work suggests it is possible to work with the child and family to develop skills, manage symptoms, and build confidence and resilience. Acting as early as possible has been found to be beneficial for bonding, child development and reducing parental anxiety.

On the evolutionary status of short-period cataclysmic variables

We present high-speed, three-colour photometry of seven short-period (Porb

Once a Criminal, Always a Criminal?: ‘Redeemability’ and the Psychology of Punitive Public Attitudes

Several studies have sought to link punitive public attitudes to attribution style and/or lay theories of crime. This research finds that those who believe criminal acts are the result of freely chosen and willful behavior are more likely to be punitive than those who feel crime is the result of external circumstances and constraints. These analyses focus on only one dimension of attributions: locus of control (internal/external). In this analysis, we include a second dimension, thought to be a better predictor of attitudes in social psychological research: stability/instability. In addition to measuring lay theories of crime causation, we also test for “belief in redeemability” (or beliefs about the ability of deviants to change their ways). Our hypothesis is that this other dimension of personal attributions (stability/instability) may be as critical in explaining support for highly punitive criminal justice policies as beliefs about criminal responsibility. We find evidence supportive of this model in an analysis of data from postal survey of residents of six areas in England.