What are expert systems and how can they contribute to Planning?

The possible role of computer‐based expert systems in town and country planning has yet to be formalised and many planners are not aware of the potential and limitations of software developments in this area. This paper defines expert systems for planners, explains their operation and outlines a possible area, within the development control process, where such systems could provide a beneficial contribution to planning.     

Supporting major new nickel developments: can Western Australia do it again?

As with several other metals, the recession of the early 1990s combined with events in the former Soviet Union, placed major strains on the world nickel market and made the operation of several established mines uneconomic. The subsequent world economic recovery, combined with the emergence of new mining and processing technologies, seems at face value to have opened the way for new and expanded nickel mines in Western Australia to expand their share of world production. Against the background of an established oligopolistic market structure and major nickel finds elsewhere, this study assesses the likelihood of major new nickel developments taking place.     

Characterisation of Acid Mine Drainage Using a Combination of Hydrometric, Chemical and Isotopic Analyses, Mary Murphy Mine, Colorado

The legacy of mining continues to affect stream water quality throughout the western United States. Traditional remediation, involving treatment of acid mine drainage from portals, is not feasible for the thousands of abandoned mines in the West as it is difficult and expensive. Thus, the development of new methods to address acid mine drainage is critical. The purpose of this study was two fold; to identify and test new tools to identify sources of metal pollution within a mine and to identify low-cost treatment alternatives through the use of these tools. Research was conducted at the Mary Murphy Mine in Colorado, a multiple-level underground mine which produced gold, silver, copper, lead and zinc from 1870 to 1951. Source waters and flowpaths within the mine were characterised using analysis of hydrogen and oxygen isotopes of water (water isotopes) in combination with solute analysis and hydrometric techniques. Hydrometric measurements showed that while discharge from a central level portal increased by a factor of 10 during snowmelt runoff (from 0.7 to 7.2 Ls^–1), Zn concentrations increased by a factor of 9 (from 3,100 to 28320gL^–1). Water isotopes were used as conservative tracers to represent of baseflow and snowmelt inputs in a hydrologic mixing model analysis. The results showed that less than 7% of peak discharge was from snowmelt. Within the mine, approximately 71% of the high-flow Zn loading was caused by a single internal stream characterised by extremely high Zn concentrations (270600gL^–1) and low pH (3.4). Somewhat surprisingly, hydrologic mixing models using water isotopes showed that new water contributed up to 79% of flow in this high-Zn source during the melt season. Diversion of this high-Zn source within the mine resulted in a decrease in Zn concentrations at the portal by 91% to 2,510gL^–1, which is lower than the base-flow Zn concentration. The results suggest that in some mines remediation efforts can be concentrated on specific areas within the mine itself. Using the characterisation techniques demonstrated in this study, problem areas can be identified and contaminated flows diverted or isolated. The results also suggest that it may be possible to dewater contamination areas, greatly reducing costs of remediation.     

Settlement of larval blacklip abalone, Haliotis rubra, in response to green and red macroalgae

Surfaces from the habitat of adult Haliotis rubra were tested as inducers of larval settlement to determine the cues that larvae may respond to in the field. Settlement was high on the green algal species Ulva australis and Ulva compressa (Chlorophyta), the articulated coralline algae Amphiroa anceps and Corallina officinalis, and encrusting coralline algae (Rhodophyta). Biofilmed abiotic surfaces such as rocks, sand and shells did not induce settlement. Ulvella lens was also included as a control. Treatment of U. australis, A. anceps and C. officinalis with antibiotics to reduce bacterial films on the surface did not reduce the settlement response of H. rubra larvae. Similarly, treatment of these species and encrusting coralline algae with germanium dioxide to reduce diatom growth did not significantly reduce larval settlement. These results suggest that macroalgae, particularly green algal species, may play an important role in the recruitment of H. rubra larvae in the field and can be used to induce larval settlement in hatchery culture.     

Increased persistence of antifouling paint biocides when associated with paint particles

Current regulatory risk assessment procedures only assess the impact of antifouling paint biocides that are released through leaching from a painted surface. Hull cleaning activities can lead to particles of antifouling paint containing biocides to enter the environment. Comparative pseudo-first order anaerobic degradation rate constants and half-lives were determined for a selection of common antifouling paint booster biocides, their degradation products, and associated with paint particles. Anaerobic half-lives of <0.5 days were calculated for chlorothalonil, dichlofluanid, and SeaNine 211, between 1 and 3 days for DCPMU and DCPU, between 14 and 35 days for diuron and CPDU, and over 226 days for GS26575 and Irgarol 1051. Increased persistence was observed when the compounds were introduced to sediments associated with antifouling paint particles. When present as antifouling paint particles, an increased half-life of 9.9 days for SeaNine 211 and 1.4 days was calculated for dichlofluanid, no significant degradation was observed for diuron. It is suspected that this is due to much of the biocide being initially bound within the matrix of the paint particle that is slowly released through dissolution processes into the sediment pore water prior to degradation. The release of booster biocides associated with paint particles into marinas has the potential to lead to their accumulation unless activities such as hull cleaning are strictly regulated.     

Relationship between different size classes of particulate matter and meteorology in three European cities

Evidence on the correlation between particle mass and (ultrafine) particle number concentrations is limited. Winter- and spring-time measurements of urban background air pollution were performed in Amsterdam (The Netherlands), Erfurt (Germany) and Helsinki (Finland), within the framework of the EU funded ULTRA study. Daily average concentrations of ambient particulate matter with a 50% cut off of 2.5 microm (PM2.5), total particle number concentrations and particle number concentrations in different size classes were collected at fixed monitoring sites. The aim of this paper is to assess differences in particle concentrations in several size classes across cities, the correlation between different particle fractions and to assess the differential impact of meteorological factors on their concentrations. The medians of ultrafine particle number concentrations were similar across the three cities (range 15.1 x 10(3)-18.3 x 10(3) counts cm(-3)). Within the ultrafine particle fraction, the sub fraction (10-30 nm) made a higher contribution to particle number concentrations in Erfurt than in Helsinki and Amsterdam. Larger differences across the cities were found for PM2.5(range 11-17 microg m(-3)). PM2.5 and ultrafine particle concentrations were weakly (Amsterdam, Helsinki) to moderately (Erfurt) correlated. The inconsistent correlation for PM2.5 and ultrafine particle concentrations between the three cities was partly explained by the larger impact of more local sources from the city on ultrafine particle concentrations than on PM2.5, suggesting that the upwind or downwind location of the measuring site in regard to potential particle sources has to be considered. Also, relationship with wind direction and meteorological data differed, suggesting that particle number and particle mass are two separate indicators of airborne particulate matter. Both decreased with increasing wind speed, but ultrafine particle number counts consistently decreased with increasing relative humidity, whereas PM2.5 increased with increasing barometric pressure. Within the ultrafine particle mode, nucleation mode (10-30 nm) and Aitken mode (30-100 nm) had distinctly different relationships with accumulation mode particles and weather conditions. Since the composition of these particle fractions also differs, it is of interest to test in future epidemiological studies whether they have different health effects.     

Differentiating work autonomy facets in a non‐Western context

Work autonomy is one important component of job design theory which in recent decades has been elaborated upon by a number of researchers who have argued that it may be disaggregated into separate work method, work schedule and work criterion autonomy facets. Breaugh (1985) developed the Work Autonomy Scales as measures of each of these. This article reports the results of two studies carried out in Egypt that explored the validity of Breaugh's scales in relation to job design theory. In Study 1, in which Breaugh's scales were administered to 534 employees in two large Egyptian organizations, the Work Autonomy Scales' three‐factor structure was verified using exploratory and confirmatory factor analyses. In Study 2, using a sample of 120 managers from four organizations, the associations between the three facets of work autonomy and other variables with which they would be expected to correlate, along with their relationships with a number of outcome variables, were explored. Statistically significant correlations were observed between certain of the work autonomy scales and task interdependence, Hackman and Oldham's autonomy scale and job complexity. In terms of outcomes, work schedule autonomy was associated with job commitment, while work criterion autonomy was associated with job satisfaction. The results are discussed in the light of previous findings and some suggestions for future research are offered. Copyright © 2003 John Wiley & Sons, Ltd.     

Land application of carbonatic lake-dredged materials: effects on soil quality and forage productivity

The ability to reuse carbonatic lake-dredged materials (CLDM) for agricultural purposes is important because it reduces offshore disposal and provides an alternative to disposal of the materials in landfills that are already overtaxed. A four-year (2001 to 2005) study on land application of CLDM as an option for disposal was conducted on a beef cattle pasture in south central Florida. The objectives of this study were (i) to assess CLDM as a soil amendment to improve quality of sandy soils in most subtropical beef cattle pastures and (ii) to determine the effect of CLDM on productivity and nutritive values of bahiagrass (BG, Paspalum notatum Flügge) in subtropical beef cattle pasture. The five treatment combinations arranged in randomized complete block design were represented by plots with different ratios (R) of natural soil (NS) to CLDM: R1 (1000 g kg(-1):0 g kg(-1)); R2 (750 g kg(-1):250 g kg(-1)); R3 (500 g kg(-1):500 g kg(-1)); R4 (250 g kg(-1):750 g kg(-1)); and R5 (0 g kg(-1):1000 g kg(-1)). Addition of CLDM had significant (p < or = 0.001) effects on soil quality and favorable influence on forage establishment and nutritive values. Compared with the control plots (0 g kg(-1)), the soils in plots amended with CLDM exhibited (i) lower penetration resistance, (ii) an increase in soil pH and exchangeable cations (Ca and Mg), and (iii) decrease in the levels of soil trace metals (Mn, Cu, Fe, Zn, and Si). Results disclosed consistently and significantly (p < or = 0.001) higher BG biomass production (forage yield = -106.3x(2) + 1015.8x - 39.2; R(2) = 0.99**) and crude protein content (CP = 1.24x + 6.48; R(2) = 0.94**) from plots amended with CLDM than those of BG planted on plots with no CLDM treatment.