Physical Acoustics

Contains reports on seven research projects.Office of Naval Research (Contract Nonr-1841(42

Identity and belonging in social learning groups : the importance of distinguishing social, operational and knowledge-related identity congruence

Collaborative learning has much to offer but not all learners participate fully and peer groups can be exclusive. The paper examines how belonging or 'congruence' in learning groups is related to identities of gender, age, ethnicity and socio-economic status. A study of student experiences of collaborative learning on three different blended learning courses illustrated how learners negotiate identity congruence with peer groups to belong and engage. An analytical framework that distinguishes social, operational and knowledge-related identity congruence has emerged. Contrary to received wisdom, the social aspect appears least important for learner engagement while knowledge-related identity congruence is fundamental. Some of the consequences of identity incongruence, particularly concerning gender and maturity, are discussed and the paper points towards the pedagogies which might enable identities of group members to shift so that collaborative learning can flourish

Sixteen years of severe Tiger snake (Notechis) envenoming in Perth, Western Australia

We aimed to describe the characteristics, clinical course, management and outcome of patients presenting to Perth teaching hospitals after envenoming by Tiger snakes. We undertook a chart review from six Perth teaching hospitals over a 16 year period from 1990 to 2005. Data were collected by a trained investigator using a preformatted data abstraction tool. We included patients bitten in the appropriate geographical area, with defibrination coagulopathy and positive Venom Detection Kit result for Tiger snake or response to specific antivenom. Of 381 charts reviewed, 23 patients were envenomed by a Tiger snake. The mean age was 36 years, 83% were male and all were bitten on a limb. First aid was applied poorly and all patients were symptomatic on presentation. Six patients developed rhabdomyolysis, one renal failure, four clinical bleeding, three neurotoxicity, one non-fatal respiratory arrest and one fatal cardiac arrest. All patients received antivenom, 13 received adrenaline premedication, with two mild allergic reactions developing in non-premedicated patients. The average dose of antivenom was four ampoules. Mean hospital stay was 2.6 days. This is the largest series of Tiger snake envenoming reported in Australia. Only one patient of 23 (4%) died, despite all patients being significantly envenomed. With rapid antivenom treatment and modern emergency and intensive care management, most patients envenomed by Tiger snakes survive

Variations de l'efficacité productive dans les coopératives françaises de travailleurs

In this study, we explore the distribution of productive efficiency among workers’ cooperatives operating in each of four sectors of French manufacturing. We use stochastic frontier panel data techniques to estimate production relationships in each sector, and to decompose output variation into input variation, variation in the effects of two indicators of the degree of worker participation in management, variation in productive efficiency, and an unexplained residual. In all four sectors we find that conventionally measured capital and labor inputs make a significant contribution to productivity. In only one sector do participation indicators contribute significantly. Variation in productive efficiency contributes significantly in all four sectors