Analysing admittance of obstacles in evanescent waveguide using the Imaginary Smith Chart

We present a technique, using the Imaginary Smith Chart, for determining the admittance of obstacles introduced into evanescent waveguide. The admittance of an inductive iris, capacitive iris, capacitive post, variable width strip and length of evanescent waveuide are investigated. © 2012 IEEE.

Increased Bandwidth Evanescent Open-Ended Waveguide Antenna Design Using the Imaginary Smith Chart

We present a novel antenna matching technique that uses the Imaginary Smith Chart to permit wideband matching of an evanescent open-ended waveguide antenna using a dielectric sheet air-spaced from the aperture. The fabricated antenna design is demonstrated to have a measured bandwidth of 24%, from 2.13–2.7 GHz, for reflection coefficient $qquad{<} -!!10~{rm dB}$ , with 2.725 GHz waveguide cutoff. The antenna's maximum aperture dimension is ${< 0.5}lambda_{0}$ at the upper frequency in the bandwidth and so it is suitable for use in a wide angle scanning phased array

Prevalence, phenomenology, aetiology and predictors of challenging behaviour in Smith-Magenis syndrome

Background

The prevalence, phenomenology aetiology and correlates of four forms of challenging behaviour in 32 children and adults with Smith-Magenis syndrome (SMS) were investigated.

Methods

Cognitive assessments, questionnaires and semi-structured interviews were used to gather data on intellectual disability, verbal and physical aggression, destructive behaviour and self-injury and on characteristics known to be associated with aggression.

Results

Aggression in SMS was more prevalent (87%), but not more severe than aggression in contrast groups. Aggressive behaviour was more frequently associated with environmental contingencies (e.g. attention, escape and access to tangibles) than self-injury and destructive behaviours. Severity of challenging behaviours was associated with high impulsivity.

Conclusion

Aggression is seen in the majority of people with SMS. Results suggest that behavioural disinhibition and operant social reinforcement are associated with the manifestation of aggression.

Causal Models of Clinically Significant Behaviors in Angelman, Cornelia de Lange, Prader-Willi and Smith-Magenis Syndromes

The operant learning theory account of behaviors of clinical significance in people with intellectual disability (ID) has dominated the field for nearly 50 years. However, in the last two decades, there has been a substantial increase in published research that describes the behavioral phenotypes of genetic disorders and shows that behaviors such as self-injury and aggression are more common in some syndromes than might be expected given group characteristics. These cross-syndrome differences in prevalence warrant explanation, not least because this observation challenges an exclusively operant learning theory account. To explore this possible conflict between theoretical account and empirical observation, we describe the genetic cause and physical, social, cognitive and behavioral phenotypes of four disorders associated with ID (Angleman, Cornelia de Lange, Prader-Willi and Smith-Magenis syndromes) and focus on the behaviors of clinical significance in each syndrome. For each syndrome we then describe a model of the interactions between physical characteristics, cognitive and motivational endophenotypes and environmental factors (including operant reinforcement) to account for the resultant behavioral phenotype. In each syndrome it is possible to identify pathways from gene to physical phenotype to cognitive or motivational endophenotype to behavior to environment and back to behavior. We identify the implications of these models for responsive and early intervention and the challenges for research in this area. We identify a pressing need for meaningful dialog between different disciplines to construct better informed models that can incorporate all relevant and robust empirical evidence.

Finding revelation in anthropology: Alexander Winchell, William Robertson Smith and the heretical imperative

Anthropological inquiry has often been considered an agent of intellectual secularization. Not least is this so in the sphere of religion, where anthropological accounts have often been taken to represent the triumph of naturalism. This metanarrative however fails to recognise that naturalistic explanations could sometimes be espoused for religious purposes and in defence of confessional creeds. This essay examines two late nineteenth-century figures – Alexander Winchell in the United States, and William Robertson Smith in Britain – who found in anthropological analysis resources to bolster rather than undermine faith. In both cases these individuals found themselves on the receiving end of ecclesiastical censure and were dismissed from their positions at church-governed institutions. But their motivation was to vindicate divine revelation, in Winchell’s case from the physical anthropology of human origins and in Smith’s from the cultural anthropology of Semitic ritual.