The use of phospholipid fatty acid analysis to measure impact of acid rock drainage on microbial communities in sediments

The impact of acid rock drainage (ARD) and eutrophication on microbial communities in stream sediments above and below an abandoned mine site in the Adelaide Hills, South Australia, was quantified by PLFA analysis. Multivariate analysis of water quality parameters, including anions, soluble heavy metals, pH, and conductivity, as well as total extractable metal concentrations in sediments, produced clustering of sample sites into three distinct groups. These groups corresponded with levels of nutrient enrichment and/or concentration of pollutants associated with ARD. Total PLFA concentration, which is indicative of microbial biomass, was reduced by >70% at sites along the stream between the mine site and as far as 18 km downstream. Further downstream, however, recovery of the microbial abundance was apparent, possibly reflecting dilution effect by downstream tributaries. Total PLFA was >40% higher at, and immediately below, the mine site (0-0.1 km), compared with sites further downstream (2.5-18 km), even after accounting for differences in specific surface area of different sediment samples. The increased microbial population in the proximity of the mine source may be associated with the presence of a thriving iron-oxidizing bacteria community as a consequence of optimal conditions for these organisms while the lower microbial population further downstream corresponded with greater sediments' metal concentrations. PCA of relative abundance revealed a number of PLFAs which were most influential in discriminating between ARD-polluted sites and the rest of the sites. These PLFA included the hydroxy fatty acids: 2OH12:0, 3OH12:0, 2OH16:0; the fungal marker: 18:2ω6; the sulfate-reducing bacteria marker 10Me16:1ω7; and the saturated fatty acids 12:0, 16:0, 18:0. Partial constrained ordination revealed that the environmental parameters with the greatest bearing on the PLFA profiles included pH, soluble aluminum, total extractable iron, and zinc. The study demonstrated the successful application of PLFA analysis to rapidly assess the toxicity of ARD-affected waters and sediments and to differentiate this response from the effects of other pollutants, such as increased nutrients and salinity.

Impact of a change in tillage and crop residue management practice on soil chemical and microbiological properties in a cereal-producing red duplex soil in NSW, Australia

The effect of a change of tillage and crop residue management practice on the chemical and micro-biological properties of a cereal-producing red duplex soil was investigated by superimposing each of three management practices (CC: conventional cultivation, stubble burnt, crop conventionally sown; DD: direct-drilling, stubble retained, no cultivation, crop direct-drilled; SI: stubble incorporated with a single cultivation, crop conventionally sown), for a 3-year period on plots previously managed with each of the same three practices for 14 years. A change from DD to CC or SI practice resulted in a significant decline, in the top 0-5 cm of soil, in organic C, total N, electrical conductivity, NH4-N, NO3-N, soil moisture holding capacity, microbial biomass and CO2 respiration as well as a decline in the microbial quotient (the ratio of microbial biomass C to organic C; P <0.05). In contrast, a change from SI to DD or CC practice or a change from CC to DD or SI practice had only negligible impact on soil chemical properties (P >0.05). However, there was a significant increase in microbial biomass and the microbial quotient in the top 0-5 cm of soil following the change from CC to DD or SI practice and with the change from SI to DD practice (P <0.05). Analysis of ester-linked fatty acid methyl esters (EL-FAMEs) extracted from the 0- to 5-cm and 5- to 10-cm layers of the soils of the various treatments detected changes in the FAME profiles following a change in tillage practice. A change from DD practice to SI or CC practice was associated with a significant decline in the ratio of fungal to bacterial fatty acids in the 0- to 5-cm soil (P <0.05). The results show that a change in tillage practice, particularly the cultivation of a previously minimum-tilled (direct-drilled) soil, will result in significant changes in soil chemical and microbiological properties within a 3-year period. They also show that soil microbiological properties are sensitive indicators of a change in tillage practice.

Cultural impact on e-service use in Saudi Arabia : the need for service oriented culture

This paper reports the results of a mixed method approach to answer: To what extent do cultural values impact on e-service use in Saudi Arabia, and if so how? This paper will firstly, introduce the importance of culture and define the aspects of Saudi culture with focus on our scope: the need for Service Oriented Culture. It will then, briefly, describe the method used and present the qualitative and quantitative findings related to the need for Service Oriented Culture. This research aims to cover a gap in the literature by investigating to what extent the presence of Service Oriented Culture, as one of Saudi Arabia’s cultural values, impacts on e-service use in Saudi Arabia. Surprisingly, the tested hypothesis was rejected: the presence of Service Oriented Culture is not a positive predictor of Intention to Use e-services in Saudi Arabia. It is evidenced that consideration of the impact of the cultural values will mainly contribute to the enhancement of ICTs implementation and use.

The impact of users' characteristics on their ability to detect phishing emails

We investigate how email users' characteristics influence their response to phishing emails. A user generally goes through three stages of behaviour upon receiving a phishing email: suspicion of the legitimacy of the email, confirmation of its legitimacy and response by either performing the action requested in the phishing email or not. Using a mixed method approach combining experiments, surveys and semi-structured interviews, we found that a user's behaviour at each stage varies with their personal characteristics such as personality traits and ability to perceive information in an email beyond its content. We found, for example, that users who are submissive, extraverted or open tend to be less suspicious of phishing emails while users who can identify cues such as inconsistent IP address, can avoid falling victim to phishing emails. Our findings enable us to draw practical implications for educating and potentially reducing the incidence of phishing emails victimisation.

Wet tropics reef rescue impact report 2009

The Wet Tropics region has a unique water asset and is also considered a priority region for the improvement of water quality entering the Great Barrier Reef due to a combination of high rainfall, intensive agricultural use, urban areas and the proximity of valuable reef assets to the coast. Agricultural activities are one of many identified threats to water quality and water flows in the Wet Tropics in terms of sediment and pollutant-related water quality decline. Information describing the current state of agricultural management practices across the region is patchy at best. Based on the best available information on agricultural management practices in the Wet Tropics in 2008, it is clear that opportunities exist to improve nutrient, sediment and pesticide management practice to reduce the impact on the water asset and the Great Barrier Reef. Based on current understandings of practices and the relationship between practices and reef water quality, the greatest opportunities for improved water quality are as follows: · nutrients – correct rate and the placement of fertilisers; · pesticides – improve weed control planning, herbicide rates and calibration practice; and · soil and sediment – implement new farming system practices. The 2008-09 Reef Rescue program sought to accelerate the rate of adoption of improved management practices and through Terrain invested $6.8M in the 2008-09 year for: · landholder water quality improvement incentive payments; · cross regional catchment repair of wetlands and riparian lands in areas of high sediment or nutrient loss; and · partnerships in the region to lever resources and support for on-ground practice change. The program delivered $3,021,999 in onground incentives to landholders in the Wet Tropics to improve farm practices from D or C level to B or A level. The landholder Water Quality Incentives Grants program received 300 individual applications for funding and funded 143 individual landholders to implement practice change across 36,098 ha of farm land. It is estimated that the Reef Rescue program facilitated practice change across 21% of the cane industry, and 20% of the banana industry. The program levered an additional $2,441,166 in landholder cash contributions and a further $907,653 in non-cash in-kind contributions bringing the total project value of the landholder grants program in the Wet Tropics to $6,370,819. Most funded projects targeted multiple water quality objectives with a focus on nutrient and sediment reduction. Of the 143 projects funded, 115 projects addressed nutrient management either as the primary focus or in combination with strategies that targeted other water quality objectives. Overall, 82 projects addressed two or more water quality targets. Forty-five percent of incentive funds were allocated to new farming system practices (direct drill legumes, zonal tillage equipment, permanent beds, min till planting equipment, GPS units, laser levelling), followed by 24% allocated to subsurface fertiliser applicators (subsurface application of fertiliser using a stool splitter or beside the stool, at the correct Six Easy Steps rate). As a result, Terrain estimates that the incentive grants achieved considerable reductions in nitrogen, phosphorus, sediment and pesticide loads. The program supported nutrient management training of 167 growers managing farms covering over 20% of the area harvested in 2008, and 18 industry advisors and resellers. This resulted in 115 growers (155 farms) developing nutrient management plans. The program also supported Integrated Weed Management training of 80 growers managing farms covering 8% of the area harvested in 2008, and 6 industry advisors and resellers. This report, which draws on the best available Reef Rescue Management Monitoring, Evaluation, Reporting, and Improvement (MERI) information to evaluate program performance and impact on water quality outcomes, is the first in a series of annual reports that will assess and evaluate the impact of the Reef Rescue program on agricultural practices and water quality outcomes. The assessment is predominantly focused on the cane industry because of data availability. In the next stage, efforts will expand to: · improve practice data for the banana and grazing industry; · gain a better understanding of the water quality trends and the factors influencing them in the Wet Tropics; in particular work will focus on linking the results of the Paddock to Reef monitoring program and practice change data to assess program impact; · enhance estimations of the impact of practice change on pollutant loads from agricultural land use; · gain a better understanding of the extent of ancillary practice (change not directly funded) resulting from Reef Rescue training/ education/communication programs; and · provide a better understanding of the economic cost of practice change across the Wet Tropics region. From an ecological perspective, water quality trends and the factors that may be contributing to change, require further investigation. There is a critical need to work towards an enhanced understanding of the link between catchment land management practice change and reef water quality, so that reduced nutrient, sediment, and pesticide discharge to the Great Barrier Reef can be quantified. This will also assist with future prioritisation of grants money to agricultural industries, catchments and sub catchments. From a social perspective, the program has delivered significant water quality benefits from landholder education and training. It is believed that these activities are giving landholders the information and tools to implement further lasting change in their production systems and in doing so, creating a change in attitude that is supportive and inclusive of Natural Resource Management (NRM). The program in the Wet Tropics has also considerably strengthened institutional partnerships for NRM, particularly between NRM and industry and extension organisations. As a result of the Reef Rescue program, all institutions are actively working together to collectively improve water quality. The Reef Rescue program is improving water quality entering the Great Barrier Reef Lagoon by catalysing substantial activity in the Wet Tropics region to improve land management practices and reduce the water quality impact of agricultural landscapes. The solid institutional partnerships between the regional body, industry, catchment and government organisations have been fundamental to the successful delivery of the landholder grant and catchment rehabilitation programs. Landholders have generally had a positive perception and reaction to the program, its intent, and the practical, focused nature of grant-based support. Demand in the program was extremely high in 2008-09 and is expected to increase in 2009-2010.

The impact of flood and post-flood cleaning on airborne microbiological and particle contamination in residential houses

In January 2011, Brisbane, Australia, experienced a major river flooding event. We aimed to investigate its effects on air quality and assess the role of prompt cleaning activities in reducing the airborne exposure risk. A comprehensive, multi-parameter indoor and outdoor measurement campaign was conducted in 41 residential houses, 2 and 6 months after the flood. The median indoor air concentrations of supermicrometer particle number (PN), PM10, fungi and bacteria 2 months after the flood were comparable to those previously measured in Brisbane. These were 2.88 p cm-3, 15 µg m-3, 804 cfu m-3 and 177 cfu m-3 for flood-affected houses (AFH), and 2.74 p cm-3, 15 µg m-3, 547 cfu m-3 and 167 cfu m-3 for non-affected houses (NFH), respectively. The I/O (indoor/outdoor) ratios of these pollutants were 1.08, 1.38, 0.74 and 1.76 for AFH and 1.03, 1.32, 0.83 and 2.17 for NFH, respectively. The average of total elements (together with transition metals) in indoor dust was 2296 ± 1328 µg m-2 for AFH and 1454 ± 678 µg m-2 for NFH, respectively. In general, the differences between AFH and NFH were not statistically significant, implying the absence of a measureable effect on air quality from the flood. We postulate that this was due to the very swift and effective cleaning of the flooded houses by 60,000 volunteers. Among the various cleaning methods, the use of both detergent and bleach was the most efficient at controlling indoor bacteria. All cleaning methods were equally effective for indoor fungi. This study provides quantitative evidence of the significant impact of immediate post-flood cleaning on mitigating the effects of flooding on indoor bioaerosol contamination and other pollutants.

Bike share's impact on car use : evidence from the United States, Great Britain, and Australia

There are currently more than 700 cities operating bike share programs. Purported benefits of bike share include flexible mobility, physical activity, reduced congestion, emissions and fuel use. Implicit or explicit in the calculation of program benefits are assumptions regarding the modes of travel replaced by bike share journeys. This paper examines the degree to which car trips are replaced by bike share, through an examination of survey and trip data from bike share programs in Melbourne, Brisbane, Washington, D.C., London, and Minneapolis/St. Paul. A secondary and unique component of this analysis examines motor vehicle support services required for bike share fleet rebalancing and maintenance. These two components are then combined to estimate bike share’s overall contribution to changes in vehicle kilometers traveled. The results indicate an estimated reduction in motor vehicle use due to bike share of approx. 90,000 km per annum in Melbourne and Minneapolis/St. Paul and 243,291 km for Washington, D.C. London’s bike share program however recorded an additional 766,341 km in motor vehicle use. This was largely due to a low car mode substitution rate and substantial truck use for rebalancing of bicycles. As bike share programs mature, evaluation of their effectiveness in reducing car use may become increasingly important. Researchers can adapt the analytical approach proposed in this paper to assist in the evaluation of current and future bike share programs.

A framework to analyze the impact of sustainable infrastructure on human productivity

The built environment has a profound impact on our natural environment, economy, health and productivity. As the majority of the people spent most of their time inside buildings, the environment in which they perform their daily activities will have an impact on their health and productivity. Studies have been conducted about the negative impacts of presence of non-favorable conditions to human health and well being. The term "Sick Building Syndrome" (SBS) is used to describe situations in which building occupants experience acute health and comfort problems that appear to be linked to their time spent in a building. Sustainable infrastructure rating systems have requirements intended to improve occupant productivity and health.While the impact of Sustainable Infrastructure in energy consumption and waste/water reduction can be measured using available tools, the impact on productivity remained as an assumption that is not clearly measured. The purpose of this research is to develop a framework to assess whether the impacts of the incorporation of features intended to improve occupants’ performance and health such as: increased ventilation, lightning and thermal comfort serve their intended purpose.

Ion impact distribution over plasma exposed nanocone arrays

The effect of an ordered array of nanocones on a conducting substrate immersed in the plasma on the transport of the plasma ions is investigated. The real conical shape of the cones is rigorously incorporated into the model. The movement of 10^5 CH3+ ions in the plasma sheath modified by the nanocone array is simulated. The ions are driven by the electric fields produced by the sheath and the nanostructures. The surface charge density and the total charge on the nanotips with different aspect ratios are computed. The ion transport simulation provides important characteristics of the displacement and velocity of the ions. The relative ion distribution along the lateral surfaces of the carbon nanotips is computed as well. It is shown that a rigorous account of the realistic nanostructure shape leads to very different distribution of the ion fluxes on the nanostructured surfaces compared to the previously reported works. The ion flux distribution is a critical factor in the nucleation process on the substrate and determines the nanostructure growth patterns.

Pulsed dc- and sine-wave-excited cold atmospheric plasma plumes: A comparative analysis

Cold atmospheric-pressure plasma plumes are generated in the ambient air by a single-electrode plasma jet device powered by pulsed dc and ac sine-wave excitation sources. Comprehensive comparisons of the plasma characteristics, including electrical properties, optical emission spectra, gas temperatures, plasma dynamics, and bacterial inactivation ability of the two plasmas are carried out. It is shown that the dc pulse excited plasma features a much larger discharge current and stronger optical emission than the sine-wave excited plasma. The gas temperature in the former discharge remains very close to the room temperature across the entire plume length; the sine-wave driven discharge also shows a uniform temperature profile, which is 20-30 degrees higher than the room temperature. The dc pulse excited plasma also shows a better performance in the inactivation of gram-positive staphylococcus aureus bacteria. These results suggest that the pulsed dc electric field is more effective for the generation of nonequilibrium atmospheric pressure plasma plumes for advanced plasma health care applications.

A model of a large-area planar plasma producer based on surface wave propagation in a plasma-metal structure with a dielectric sheath

A theoretical model of a large-area planar plasma producer based on surface wave (SW) propagation in a plasma-metal structure with a dielectric sheath is presented. The SW which produces and sustains the microwave gas discharge in the planar structure propagates along an external magnetic field and possesses an eigenfrequency within the range between electron cyclotron and electron plasma frequencies. The spatial distributions of the produced plasma density, electromagnetic fields, energy flow density, phase velocity and reverse skin depth of the SW are obtained analytically and numerically.

The effect of near-sheath dusts on a surface-wave-sustained gas discharge

The effect of near-sheath dusts on the rf power loss in a surface-wave-sustained gas discharge is studied. The planar plasma is bounded by a dielectric and consists of an inhomogeneous near-wall transition layer (sheath), a dusty plasma layer and an outer dust-free plasma. The discharge is maintained by high-frequency axially symmetrical surface waves. The surface-wave power loss from the most relevant dissipative mechanisms in typical discharge plasmas is analysed.

Nonresonant power transfer in plasma-surface interactions via two-surface wave decay

The excitation of pairs of electron surface waves via nonresonant decay of plasma waves incident onto a solid surface is studied in the context of controlling the interaction of pulsed electromagnetic radiation with plasma-exposed solid surfaces. The role of the plasma-exposed surfaces in nonlinear heating of the plasma edge and related power transfer is discussed. It is shown that the maximum efficiency of the power transfer at solid surfaces with dielectric permittivity εd <3 corresponds to the resonant two-surface wave decay. On the other hand, for solids with εd >3 the maximum power transfer efficiency is achieved through nonresonant excitation of the quasistatic surface waves. In this case the plasma waves generated by external radiation dissipate their energy into the plasma periphery most effectively.

Parameters and equilibrium profiles for large-area surface-wave sustained plasmas

The equilibrium profiles of the plasma parameters of large-area if discharges in a finite-length metal-shielded dielectric cylinder are computed using a two-dimensional fluid code. The rf power is coupled to the plasma through edge-localized surface waves traveling in the azimuthal direction along the plasma edge. It is shown that self-consistent accounting for axial plasma diffusion and radial nonuniformity of the electron temperature can explain the frequently reported deviations of experimentally measured radial density profiles from that of the conventional linear diffusion models. The simulation results are in a good agreement with existing experimental data obtained from surface-wave sustained large-diameter plasmas. © 2002 The American Physical Society.