The consequences of land use change on nutrient exports: a regional scale assessment in south-west Victoria, Australia

Estimation of nutrient load production based on multi-temporal remotely sensed land use data for the Glenelg-Hopkins region in south-west Victoria, Australia, is discussed. Changes in land use were mapped using archived Landsat data and computerised classification techniques. Land use change has been rapid in recent history with 16% of the region transformed in the last 22 years. Total nitrogen and phosphorus loads were estimated using an export coefficient model. The analysis demonstrates an increase in modelled nitrogen and phosphorus loadings from 1980 to 2002. Whilst such increases were suspected from past anecdotal and ad-hoc evidence, our modelling estimated the magnitude of such increases and thus demonstrated the enormous potential of using remote sensing and GIS for monitoring regional scale environmental processes.     

Methylmercury exposure and health effects in humans: a worldwide concern

The paper builds on existing literature, highlighting current understanding and identifying unresolved issues about MeHg exposure, health effects, and risk assessment, and concludes with a consensus statement. Methylmercury is a potent toxin, bioaccumulated and concentrated through the aquatic food chain, placing at risk people, throughout the globe and across the socioeconomic spectrum, who consume predatory fish or for whom fish is a dietary mainstay. Methylmercury developmental neurotoxicity has constituted the basis for risk assessments and public health policies. Despite gaps in our knowledge on new bioindicators of exposure, factors that influence MeHg uptake and toxicity, toxicokinetics, neurologic and cardiovascular effects in adult populations, and the nutritional benefits and risks from the large number of marine and freshwater fish and fish-eating species, the panel concluded that to preserve human health, all efforts need to be made to reduce and eliminate sources of exposure.     

Age of licensure and monitoring teenagers' driving: survey of parents of novice teenage drivers

OBJECTIVE: To assess parental decision making regarding the timing of teenagers initiating driving and monitoring teenagers' driving after licensure. METHODS: About 300 parents were interviewed during spring 2006 in Minnesota, North Carolina, and Rhode Island, states with varying licensing provisions, while teenagers took their first on-road driving tests. RESULTS: States' differences in ages of obtaining learner's permits and licenses reflected different licensing laws, but most teenagers obtained permits and took road tests within the first few months after they became eligible. Common reasons for delaying obtaining permits were fulfilling driver education requirements and lack of readiness/immaturity. Insufficient practice driving most often delayed licensure. Among the parents interviewed, 33-49% believed the minimum licensure age should be 17 or older. Almost all parents planned to supervise teenagers' driving after licensure, and most wanted to know about speeding or distractions. When asked about in-vehicle devices to monitor teenagers' driving, 37-59% of parents had heard of them. Parents were least interested in using video cameras and about equally interested in computer chips and cell-phone-based GPS systems. Disinterest in monitoring devices most often was attributed to trusting teenagers or respecting their privacy. CONCLUSIONS: Licensing laws influence ages of initiating driving. Although many parents support licensing at 17 or older - higher than in all but one state - most teenagers initiate driving soon after reaching the minimum age. Parents plan to supervise teenagers' driving, and many say they are open to using in-vehicle monitoring devices. IMPACT ON INDUSTRY: Many parents support a minimum licensing age of 17 or older and would consider in-vehicle devices to extend their supervision of teenager's driving.     

Rational decision processes and sex discrimination: Testing ‘rational’ bias theory

The extent to which sex discrimination is likely to occur as a consequence of manager-client relationships was examined in this test of rational bias theory. Results were gathered by means of a computerized survey technique. Findings indicated that discrimination is more likely to occur in relationships in which the client is relatively important to the manager, but less likely to occur, or be reversed, in the presence of conditions signaling that the client disapproves of discrimination. The findings partly supported the prediction that managers in relatively weaker positions more readily discriminate. The analysis offers theoretical and policy implications for future consideration.     

Landscape planning and the estate landscape

The country estate has a particular place in the English countryside and its contribution to the landscape scene is distinct and valuable. The paper describes an approach to planning a large country estate of parkland, woodland and estate villages in Cheshire. A Reconnaissance Survey led to the Outline Strategy for six ‘landscape types’ discovered on the estate. The Landscape Conservation Plan is described and the crucial importance of conservation measures is emphasised.     

Cooperative breeding in purple gallinules: the role of helpers in feeding chicks

Summary The participation of breeders and helpers in the feeding of 21 broods of chicks was studied in a population of cooperatively breeding purple gallinules (Porphyrula martinica). In the breeding group, all birds over the age of 2 months fed chicks. Female breeders fed chicks at the highest rate, followed by male breeders and adult helpers, old juvenile helpers, and young juvenile helpers. The amount of food breeders fed chicks was independent of the number of helpers in the breeding group. However, breeders made fewer feeding visits when they had helpers. Male and female breeders spent similar amounts of time feeding chicks. Helpers spent significantly less time feeding chicks than did breeders. As helpers grew older they fed chicks at a faster rate, made more feeding visits and spent more time feeding chicks. Analysis of variance was used to determine which variables explained the variation in the brood feeding rate (amount of food delivered to an entire brood during one observation). Age of chicks had a significant nonlinear effect, and size of brood and number of helpers had significant linear effects on the brood feeding rate. Chicks in groups with helpers received more food and were accompanied for longer periods of time than chicks in groups without helpers; either or both of these factors may have led to increased chick survival.