Characterisation of hidden defects using the near-field ultrasonic enhancement of Lamb waves.

Defects that propagate from the inside of a structure can be difficult to detect by traditional non-destructive inspection methods. A non-contact inspection method is presented here that uses the near-field interactions of ultrasonic Lamb waves to detect defects propagating into a 1.5 mm thick aluminium sheet from the opposite side to that which is inspected. Near-field interactions of the S0 Lamb waves with the defects are shown to give rise to a characteristic increase in the wave magnitude, which is used to position and characterise these hidden defects. It is shown that such defects are difficult to detect from a study of their influence on ultrasonic transmission alone. Single defects of different depths, and systems of multiple defects with varying separations and relative depths, are successfully detected in both experimental trials and FEM simulations. Reliable single defect detection is achieved for defects with a minimum depth of 30% of the plate thickness, and resolution of multiple defects is achieved for defect separations of 5mm.

Kava use, dyslipidaemia and biomarkers of dietary quality in Aboriginal people in Arnhem Land in the Northern Territory (NT), Australia.

Heavy kava use has been associated with sudden death in Aboriginal Australians in Arnhem Land (Northern Territory, Australia) where poor diets and a high incidence of premature coronary heart disease are known. Heavy kava users may suffer additional risk if further malnourished. Among 98 people (62 males, 36 females) in one community, 36 never used kava, 26 were past users, and 36 were continuing users. Across kava-using groups skinfold thickness, body mass index and body fat decreased. Total- and LDL-cholesterol were elevated in kava users compared to both former users and never users. HDL-cholesterol was higher in current users vs never users. Across kava-using groups, triglycerides, homocysteine and diet-derived antioxidant vitamins alpha-tocopherol and retinol, did not vary. Plasma carotenoid levels (indicative of vegetable and fruit intake) were very low, but when adjusted for plasma cholesterol, did not vary between kava-using groups. An obsession for kava drinking may mediate kava's direct effects on nutritional status.

Case-control study of the association between kava use and pneumonia in eastern Arnhem and Aboriginal communities (Northern Territory, Australia).

Pneumonia causes significant morbidity and mortality in Aboriginal populations in Australia's Northern Territory (NT). Kava, consumed in Arnhem Land since 1982, may be a risk factor for infectious disease including pneumonia. A case-control study (n = 115 cases; n = 415 controls) was conducted in 7001 Aboriginal people (4217 over 15 years). Odds ratios (OR) were calculated by conditional logistic regression with substance use and social factors as confounders. Pneumonia was not associated with kava use. Crude OR = 1.26 (0.74-2.14, P = 0.386), increased after controlling for confounders (OR = 1.98, 0.63-6.23, P = 0.237) but was not significant. Adjusted OR for pneumonia cases involving kava and alcohol users was 1.19 (0.39-3.62, P = 0.756). In communities with longer kava-using histories, adjusted OR was 2.19 (0.67-7.14, P = 0.187). There was no kava dose-response relationship. Crude ORs for associations between pneumonia and cannabis use (OR = 2.27, 1 18-4.37, P = 0.014) and alcohol use (OR = 1.95, 1.07-3.53, P = 0.026) were statistically significant and approached significance for petrol sniffing (OR = 1.98, 0.99-3.95, P = 0.056).

Health effects of kava use in an eastern Arnhem Land Aboriginal community.

BACKGROUND: Heavy kava use in Aboriginal communities has been linked to various health effects, including anecdotes of sudden cardiac deaths. AIMS: To examine associations between kava use and potential health effects. METHODS: A cross-sectional study was carried out within a kava-using east Arnhem Land Aboriginal community in tropical northern Australia. One-hundred-and-one adults who were current, recent or non-users of kava were enrolled in March 2000. Main outcome measures were physical, anthropometric, biochemical, haematological, immunological and neurocognitive assessments. RESULTS: Kava users more frequently showed a characteristic dermopathy (P<0.001). They had increased levels of gamma-glutamyl transferase and alkaline phosphatase (P<0.001). Lymphocyte counts were significantly lower in kava users (P<0.001). Fibrinogen, plasminogen activator inhibitor-1 and neurocognitive tests were not different between kava use categories. IgE and IgG antibodies were elevated across the whole group, as were C-reactive protein and homocysteine. CONCLUSIONS: Kava use was associated with dermopathy, liver function abnormalities and decreased lymphocytes. If kava continues to be used by Aboriginal populations, monitoring should focus on the health consequences of these findings, including a possible increase in serious infections. The interaction between kava, alcohol and other substances requires further study. Although markers of cardiovascular risk are increased across the population, these were not higher in kava users, and this increase may be linked to the large infectious pathogen burden reflective of the socioeconomic disadvantage seen in many remote Aboriginal communities.

Resource requirements to develop a large, remote aboriginal health service: whose responsibility?

In 1994 the Commonwealth funded studies to establish and develop Aboriginal health services. One such study was undertaken in 1995 at Maningrida, Northern Territory: to identify the health-service needs of the population and consider community management structures; to identify Northern Territory expenditure for primary health care; and to provide a three- to five-year development budget. Approximately 2100 Aboriginal residents in the region used the service, including 750 living on 24 outstations within 75 km. Nearly 40 per cent were aged under 15 years. Childhood morbidity was high, with children under two averaging 1.4 hospital admissions per year. The age pyramid reflected premature adult mortality from the third decade of life. Service providers identified inadequate staffing and infrastructure as barriers to service development. Community consultations emphasised the need for resident doctors, improved outstation services and aged and respite care, local training for Aboriginal health workers and housing for staff. These developments would require per capita primary health care expenditure ($872) to be doubled. Aboriginal people in remote areas are disadvantaged through Commonwealth Grants Commission funding formulae and lack of Medicare access. As the sole funding source, the Northern Territory spends over $1.83 million per year providing health services at Maningrida. Additionally, the study proposed that the Commonwealth spend $1.96 million a year over five years on staffing and infrastructure. Local Aboriginal organisations also agreed to allocate resources for health service development. Ineffective implementation, lack of clarification of government responsibilities and funding shortfalls remain barriers to developing remote Aboriginal health services.