Monitoring genetic diversity in tropical trees with multilocus dominant markers

Since no universal codominant markers are currently available, dominant genetic markers, such as amplified fragment length polymorphism (AFLP), are valuable tools for assessing genetic diversity in tropical trees. However, the measurement of genetic diversity (H) with dominant markers depends on the frequency of null homozygotes (Q) and the fixation index (F) of populations. While Q can be estimated for AFLP loci, F is less accessible. Through a modelling approach, we show that the monolocus estimation of genetic diversity is strongly dependent on the value of F, but that the multilocus diversity estimate is surprisingly robust to variations in F. The robustness of the estimate is due to a mechanistic effect of compensation between negative and positive biases of H by different AFLP loci exhibiting contrasting frequency profiles of Q. The robustness was tested across contrasting theoretical frequency profiles of Q and verified for 10 neotropical species. Practical recommendations for the implementation of this analytical method are given for genetic surveys in tropical trees, where such markers are widely applied.

Diagnosis of autistic spectrum disorders in Queensland: Variations in practice

Objective: For both paediatricians and child psychiatrists, referrals to assess possible autistic spectrum disorders (ASD) are increasing. This study examines current practices of medical specialists in the assessment of these disorders. Methods: An anonymous, self-report questionnaire was sent to all Queensland paediatricians and child psychiatrists. The survey elicited frequencies of consultation for ASD, diagnostic method, advice provided and perceived adequacy of training for this work. Results: Responses were received from 79 (85%) eligible paediatricians and 26 (58%) eligible child psychiatrists. For one-third of all clinicians, new consultations for possible ASD occurred as often as 2-3 times per week. Most specialists approached the clinical diagnosis of ASD by considering history from different sources and professional assessments. Paediatricians (86%) were more likely than child psychiatrists (62%) to request genetic studies for children with severe autism (P = 0.01). Both general paediatricians and developmental paediatricians perceived level of training for possible ASD consultations was significantly worse than child psychiatrists (P < 0.001 and P = 0.02, respectively), but no difference was found between paediatric groups (P = 0.27). Perceived adequacy of specialist training was not associated with length of experience in clinical practice. Conclusion: Medical practice in Queensland around diagnosis of ASD is characterized by considerable variability. There is still a long way to go if we are to achieve consistency around medical issues of organic diagnosis and practices impacting on health as well as consideration of differential developmental diagnoses. The finding that recently trained paediatricians felt just as unprepared for this work as their older colleagues suggests that the graduate training response to this 'new morbidity' has not been adequate.

Optimal design of a regenerative dynamic dynamometer using genetic algorithms

This paper presents an approach for optimal design of a fully regenerative dynamic dynamometer using genetic algorithms. The proposed dynamometer system includes an energy storage mechanism to adaptively absorb the energy variations following the dynamometer transients. This allows the minimum power electronics requirement at the mains power supply grid to compensate for the losses. The overall dynamometer system is a dynamic complex system and design of the system is a multi-objective problem, which requires advanced optimisation techniques such as genetic algorithms. The case study of designing and simulation of the dynamometer system indicates that the genetic algorithm based approach is able to locate a best available solution in view of system performance and computational costs.