Biodiversity and Dynamics (Rate of Change) of Bacterial Communities Involved in the Biodegradation of Petroleum Refinery Sludge in Contaminated Soils

Aim: The study assessed the bio treatability of the petroleum refinery sludge in contaminated soils by indigenous bacterial communities and the effects of the sludge contamination and bio stimulants on the biodiversity and dynamics (rate of change) of the bacterial communities involved in the biodegradation of the sludge, using the molecular biology technique, Denaturing Gradient Gel Electrophoresis (DGGE). Study Design: The randomnized block design was used for the study. Place and duration of the Study: The research was conducted in the biology laboratory of Flinders University, Adelaide, South Australia. Methodology: The percentage of total petroleum hydrocarbons (TPH) degraded and the bacterial load in the test microcosms was assessed tri-weekly for 12 weeks. The percentage TPH was assessed using Gas chromatography, while the bacterial count was determined as gene copies using the culture independent molecular tool, quantitative real-time PCR (qRt-PCR) analysis. The effects of the experimental treatments on the biodiversity and dynamics (rate of change) of the bacterial communities involved in the biodegradation of the sludge in the soils was determined by the culture-independent molecular biology technique, DGGE. Moving Windows Analysis (MWA) and Shannon Weaver diversity index were used to determine the dynamics (rate of change) and biodiversity of the bacterial communities respectively. Results: Results obtained for the Moving Window Analysis (MWA) which is used to determine the dynamics (Dy), or rate of change of the bacterial communities, showed that, the 1% and 5% sludge contaminated soils biostimulated with compost, recorded the highest Dy of 86.0 ± 1.90% and 87.0 ± 2.20% respectively.NPK biostimilated soil microcosms however recorded a lower Dy of 33.75± 3.20 and 32.50 ± 4.68% for 1% and 5% sludge contamination respectively. The biodiversity of the bacterial communities expressed as Shannon -Weaver index (H1), recorded the highest value of 2.76 ±0.02 for the compost biostimulated microcosm in the 1% sludge treatment, while for the 5% sludge contamination, the treatment with NPK and surfactant enhanced the bacterial biodiversity most with a value of 2.76 ±0.07%. In the test soils with 1% sludge contamination, bio stimulation with NPK gave the highest % TPH degradation (78.25%) while the treatment with NPK and Triton-X 100 had the highest TPH degradation (46.55%) for the 5% sludge contaminated soils. There was insignificant difference in the % sludge degradation between the control and other treatments at P > 0.05 and F = 4.07 for the 1% sludge treated soils, while for the soils treated with 5% sludge there was significant difference between the control and other treatments at P < 0.05 and F= 4.07. Conclusion: Bacteria species identified in the sludge by molecular biology techniques included; Pseudomonas sp. ITRI77, Uncultured Thauera sp., Uncultured Pseudomonas sp., Flavobacterium sp., Bacillaceae bacterium, Uncultured soil bacterium, Clostridium sp., most of which are Gram negative. Biostimulation with compost enhanced a higher biodiversity (H i) and dynamics (Dy) of the bacterial communities involved in the biodegradation of the sludge. Though the NPK treated soils enhanced the biodegradation of the sludge most, degradation started declining by the 9th week while that of compost continued to rise steadily till the 12th week. Results obtained indicate that compost is as good as NPK in the biodegradation of petroleum sludge especially at 1% sludge contamination, since there was no statistical difference between the % TPH degraded and the use of compost is environmentally friendly and economically sustainable.

A Refined Technique to Calculate Finite Helical Axes From Rigid Body Trackers

Finite helical axes (FHAs) are a potentially effective tool for joint kinematic analysis. Unfortunately, no straightforward guidelines exist for calculating accurate FHAs using prepackaged six degree-of-freedom (6DOF) rigid body trackers. Thus, this study aimed to: (1) describe a protocol for calculating FHA parameters from 6DOF rigid body trackers using the screw matrix and (2) to maximize the number of accurate FHAs generated from a given data set using a moving window analysis. Four Optotrak® Smart Markers were used as the rigid body trackers, two moving and two fixed, at different distances from the hinge joint of a custom-machined jig. 6DOF pose information was generated from 51 static positions of the jig rotated and fixed in 0.5 deg increments up to 25 deg. Output metrics included the FHA direction cosines, the rotation about the FHA, the translation along the axis, and the intercept of the FHA with the plane normal to the jig's hinge joint. FHA metrics were calculated using the relative tracker rotation from the starting position, and using a moving window analysis to define a minimum acceptable rotational displacement between the moving tracker data points. Data analysis found all FHA rotations calculated from the starting position were within 0.15 deg of the prescribed jig rotation. FHA intercepts were most stable when determined using trackers closest to the hinge axis. Increasing the moving window size improved the FHA direction cosines and center of rotation accuracy. Window sizes larger than 2 deg had an intercept deviation of less than 1 mm. Furthermore, compared to the 0 deg window size, the 2 deg window had a 90% improvement in FHA intercept precision while generating almost an equivalent number of FHA axes. This work identified a solution to improve FHA calculations for biomechanical researchers looking to describe changes in 3D joint motion.

Normal Operating Range of Bacterial Communities in Soil Used for Potato Cropping

ABSTRACTIn this study, the impacts of six potato (Solanum tuberosum) cultivars with different tuber starch allocations (including one genetically modified [GM] line) on the bacterial communities in field soil were investigated across two growth seasons interspersed with 1 year of barley cultivation, using quantitative PCR, clone library, and PCR-denaturing gradient gel electrophoresis (DGGE) analyses. It was hypothesized that the modifications in the tuber starch contents of these plants, yielding changed root growth rates and exudation patterns, might have elicited altered bacterial communities in the soil. The data showed that bacterial abundances in the bulk soil varied over about 2 orders of magnitude across the 3 years. As expected, across all cultivars, positive potato rhizosphere effects on bacterial abundances were noted in the two potato years. The bulk soil bacterial community structures revealed progressive shifts across time, and moving-window analysis revealed a 60% change over the total experiment. Consistent with previous findings, the community structures in the potato rhizosphere compartments were mainly affected by the growth stage of the plants and, to a lesser extent, by plant cultivar type. The data from the soil under the non-GM potato lines were then taken to define the normal operating range (NOR) of the microbiota under potatoes. Interestingly, the bacterial communities under the GM potato line remained within this NOR. In regard to the bacterial community compositions, particular bacterial species in the soil appeared to be specific to (i) the plant species under investigation (barley versus potato) or, with respect to potatoes, (ii) the plant growth stage. Members of the generaArthrobacter,Streptomyces,Rhodanobacter, andDokdonellawere consistently found only at the flowering potato plants in both seasons, whereasRhodoplanesandSporosarcinawere observed only in the soil planted to barley.

Swiss tree lines - a GIS-based Approximation

Mountain timber lines are relevant in the context of land abandonment and climate change. For Switzerland, GIS-compliant delimitations of the tree line and the forest line are still lacking. Recent high-resolution landcover information offers new possibilities for GIS-based approaches. In a Swiss-wide study, an analysis based on slope zones was combined with a moving-window analysis to assess tree and forest line altitude, using topographic data. The tree and the forest lines were delimited at the upper altitude reached by a tree or closed forest respectively. The model delivered a fine-scaled delimitation sensitive to local conditions. The results indicate that earlier studies underestimated the tree line altitudes for the fringes of the Alps. Also the variability inside climatic and bio-geographical regions is larger than it was estimated up to now.

Wetland habitat selection by woodland caribou as characterized using the Alberta Wetland Inventory

We examined habitat selection by woodland caribou (Rangifer tarandus caribou) in northwestern Alberta based on a wetland classification system developed for the Alberta Vegetation Inventory. Our two objectives were to describe caribou habitat use, and to assess the utility of the wetland classification system in land-use planning on caribou range. We used a geographical information system to overlay the locations of radio-collared caribou on the habitat map. Using a "moving-window" analysis of habitat availability, we examined patterns of habitat selection by 16 individual female caribou during five seasons annually over two years. We did not detect significant differences in habitat selection patterns among seasons. Caribou showed significant preferences for both bogs and fens with low to moderate tree cover relative to marshes, uplands, heavily forested wetlands, water, and areas of human use. The wetland classification system appears to have value for broad-scale planning of industrial activity on caribou range. More-detailed descriptions of vegetation, especially understory species, are required to refine this system for operational-level forest harvest planning.

Determination of Modal Parameters in Complex Nonlinear Systems

This paper describes a methodology for evaluating the modal parameters of complex nonlinear systems. It combines four different tools: the Coleman post-processing, the partial Floquet analysis, the moving window analysis, and the signal synthesis algorithm. The approach provides a robust estimation of the linearized modal parameters and qualitative information about the nonlinear behavior of the system. It operates on one or multiple discrete time signals and is able to deal with both time-invariant and periodic systems. The method is computationally inexpensive and can be used with multiphysics computational tools, and in principle, with experimental data. The proposed approach is validated using a simple, four degree of freedom model of a wind turbine. The predictions for the linear system are validated against an exact solution of the problem. For the nonlinear system, it is demonstrated that qualitative information concerning the nonlinear behavior of the system is obtained using the proposed method. Finally, the nonlinear behavior of a realistic, three-bladed horizontal axis wind turbine model is investigated.

Identification of Regional Climatic Conditions Favorable for Development of European Canker of Apple

Months of the year with high risk of European canker (Neonectria galligena) development in areas of the United States, Chile, England, and Northern Ireland were determined from published data. Moving-window analysis of long-term climatic data was used to classify disease risk in these areas in relation to rainfall and temperature conditions using the degree of agreement statistic. Greatest agreement occurred when it both rained on >30% of days/month and there was an average of >8 h/day with temperature of 11 to 16°C. When these thresholds were applied in eight validation areas in New Zealand, Australia, the United States, The Netherlands, and Denmark, areas with reported higher risk of disease tended to be areas where the thresholds were exceeded more often and by greater amounts. Areas at higher latitudes (>52°) with frequent summer rainfall appeared to be most prone to European canker, including the fruit rot phase of the disease, probably because summer temperatures were more favorable than at lower latitudes. The climatic thresholds derived for European canker could be useful for studies of disease establishment risk, surveillance, eradication, climate change impact assessment, and, possibly, for disease risk forecasting. The methods used in this study allowed conditions favorable for disease development to be identified even though quantitative regional disease data were lacking, and they could be useful for similar geoclimatic studies of other diseases.