Theoretically optimal forms for very long-span bridges under gravity loading.

Long-span bridges have traditionally employed suspension or cable-stayed forms, comprising vertical pylons and networks of cables supporting a bridge deck. However, the optimality of such forms over very long spans appears never to have been rigorously assessed, and the theoretically optimal form for a given span carrying gravity loading has remained unknown. To address this we here describe a new numerical layout optimization procedure capable of intrinsically modelling the self-weight of the constituent structural elements, and use this to identify the form requiring the minimum volume of material for a given span. The bridge forms identified are complex and differ markedly to traditional suspension and cable-stayed bridge forms. Simplified variants incorporating split pylons are also presented. Although these would still be challenging to construct in practice, a benefit is that they are capable of spanning much greater distances for a given volume of material than traditional suspension and cable-stayed forms employing vertical pylons, particularly when very long spans (e.g. over 2 km) are involved.

Musical key perception in relation to color.

A link between musical keys and colors is common among musicians, although there has never been any agreement about which color matches which key. This study tested two alternative key-color associations: E is red and Eb is green, or vice versa. 21 participants (10 men, 11 women; M age = 20 yr., SD = 3.3) with absolute pitch listened to melodies beginning with an anacrusis and a perfect cadence which were played through in C major. Then the melodies began in another key, while four or two colored squares were displayed (in Experiments 1 and 2, respectively). Participants were asked to chose the color which best matched the quality of the new key. The results showed strong support for the E red / Eb green linkage.

The predictors of distress in parents of children with autism spectrum disorder.

BACKGROUND: It is well recognised that parents of children with autism spectrum disorder (ASD) often experience clinically significant levels of stress and depression. This study examined which ASD characteristic best predicted parental distress. METHOD: Parents of 109 children aged between 4 and 12 (M age = 7.89, SD = 2.43) completed self-report measures of anxiety, depression, stress, and parenting-specific stress. They also completed rating scales regarding their child's ASD characteristics. RESULTS: This study found that the child's behavioural and emotional impairments predicted the parents' overall levels of distress (i.e., stress/tension, anxiety, and depression), but not the stress associated with parenting. Instead, the child's social impairment severity was found to predict parenting-specific stress. CONCLUSION: This study highlights the pervasive influence of ASD symptomatology on the mental wellbeing of the parents and the importance of assisting parents to cope with the behavioural and social impairments of their child.

Survival following whole brain radiation treatment for cerebral metastases: an audit of 474 patients.

BACKGROUND AND PURPOSE: To report the outcome of patients with brain metastases from solid tumors treated with whole brain radiotherapy (WBRT) in a single institution. Given the high proportion of melanoma patients, a secondary aim was to compare our outcomes for patients with melanoma to those with other cancers. PATIENTS AND METHODS: A retrospective audit identified 474 patients treated between January 1983 and December 1999. Survival was calculated using the Kaplan-Meier method. Cox regression modeling was used for multivariate analysis. RESULTS: Four hundred and fifty nine patients have died from their disease. The median survival was 4.1 months for the whole group and 3.6 months for the 42% of patients with melanoma. The 1 and 2 year survival was 15 and 5%. Six patients lived beyond 5 years. 105 of 186 patients with a single brain metastasis underwent surgery plus WBRT, and 81 received WBRT alone. Median survival was 8 and 4 months, respectively, (P<0.0001). 30 Gy in 10 fractions was used more commonly in the early part of the study compared to 20 Gy in 5 fractions more recently. There was no difference in survival by time period. CONCLUSIONS: The survival in this series was comparable to other studies. Performance status, resection, dose, and the presence of extracranial disease appeared to be significant prognostic factors. The survival for the large number of patients with melanoma did not differ from the rest of the cohort.