Bioremediation Kinetics of Crude Oil at 5°C

This bench scale experiment investigated the mineralization of crude oil at cold temperatures. Biodegradation rates of Alberta Sweet Mix crude oil at 5°C and at ambient temperatures (21°C) were compared. The experimental design consisted of 14 soil columns. Off-gas samples for each column were analyzed every second day using a gas chromatograph to determine CO2 production rates. The run lasted for 219 days, at which time the soil columns were sacrificed for analysis. Oil mineralization values were modeled by a number of methods, including CO2 production determination from GC measurements and gravimetrically determined hydrocarbon loss using soxhlet extraction. The results of the experiment suggested that temperature only affected the biodegradation rates of crude oil in the initial phase of the biodegradation process. After approximately 3 months, the degradation rates of crude oil at 5°C and 21°C were similar at about 11 mg hydrocarbon∕kg dry soil∕day. The conclusion of this study was that significant mineralization of Alberta Sweet Mix crude oil can occur at cold temperatures.     

Optimization of Pheromone Lure and Trap Characteristics for Currant Clearwing, <Emphasis Type="Italic">Synanthedon tipuliformis</Emphasis>

Currant clearwing Synanthedon tipuliformis (Sesiidae) has been a pioneering and successful target of mating disruption in New Zealand, with virtually universal black currant industry adoption since c. 1990. Recent unexplained control failures using mating disruption lead to questions about pheromone efficacy. In this study, we have investigated the possible reasons for reduced control from mating disruption, and report improvements in trap catch based on pheromone loading and trap color. No differences were found in electrophysiological responses to pheromone components from two New Zealand populations. Male moth catches in traps baited with synthetic lures were disrupted in the presence of mating disruption dispensers (> 99.99%) indicating no apparent barrier to efficacy from the pheromone formulation. Field behavioral observations confirmed this result. Male attraction to yellow delta traps was equivalent to green delta traps, but was greater than to red, black, blue, or white traps. Solid yellow delta traps were more attractive than black traps with yellow stripes, the latter designed to mimic the color pattern of the insect. Solid yellow funnel traps were less attractive than a composite of green, yellow, and white funnel traps. Trap catch increased as a function of pheromone loading and trap color. In another experiment conducted in Tasmania, there was no difference in catch with single component [(E,Z)-2,13-octadecadienyl acetate] or two component lures [97% (E,Z)-2,13-octadecadienyl acetate:3% (E,Z)-3,13-octadecadienyl acetate], refuting the suggestion of a different pheromone strain there.     

Adaptive classification of myocardial electrogram waveforms

The shape of myocardial electrogram complexes can change gradually in response to electrical and physiological transients. These changes could affect the reliability of morphologic-based electrogram classifiers proposed for use in implantable cardioverters. Here the authors present a method of detecting gradual changes in the shape of electrogram complexes and evaluate the method by incorporating it into a simple adaptive classification scheme. Of the six subjects recruited to take part in a previous comparative study of myocardial electrogram features, the authors observed extensive morphologic drift of normal sinus beats in two subjects. The results indicate that the adaptive classification scheme proposed here can reduce observed classification error rates compared to rates obtained without adaptation     

Characterization of a stable L-form of the fish pathogen Aeromonas salmonicida

In this experiment, the sensitivity of human osteosarcoma cells to various concentration gradients of HDMTX, VCR, CBP, MMC, VP16, PMB and their time-effect relationship were examined in vitro with MTT assay among 23 cases' fresh osteosarcoma (OS) tissues. It was found that OS was sensitive to MMC and PMB when the drug concentrations were equal to the calculated in vivo drug concentrations. When the concentrations were 5 times as high as those of the calculated in vivo concentrations, OS was sensitive to HDMTX, CBP, MMC and PMB. The positive rates of sensitivity were highest in 72 hours with an average of 55.1%.     

Optimal reactor size distribution with fixed terminal constraints

The method of Lagrange multipliers is applied to find the optimal size distributions of isothermal continuous stirred tank reactors (CSTR) with fixed terminal constraints, to carry out a simple reaction. The control variables minimizing the Lagrangian of the problem can be found by the well known first and second order gradient techniques, or simply by using a non-linear root finder computer program. The technique is also applicable to non- isothermal CSTR optimization.     

The Effect of Atmospheric Pheromone Concentrations on Behavior of Lightbrown Apple Moth in an Apple Orchard

A previously validated Lagrangian model was used to estimate the threshold of atmospheric pheromone concentration required to prevent trap catch and wing fanning in mating disruption plots in an apple orchard. Electroantennogram (EAG) traces of 10 min duration were recorded, along with supporting meteorological data needed for the model, to better define the conditions in which successful mating disruption will occur. Pheromone was released from polyethylene tubing dispensers into orchard blocks treated with 10, 100, 1000, and 2000 dispensers/ha. Predicted dusk concentrations of atmospheric pheromone at a height of 1.85 m varied nightly between 4 and 90 ng pheromone/m³ (in plots treated with 1000 dispensers/ha) over 11 weeks. Disruption of traps baited with 1000-g pheromone lures followed an asymptotic curve with predicted concentration, but they did not show a significant effect of trap height (1.5 and 3.0 m). Wing fanning was reduced by increasing the density of dispensers, but was not completely eliminated even at 1000 dispensers/ha. At this density, the concentrations were usually <16 ng pheromone/m³. Electroantennogram recordings of 10 min duration showed a higher frequency of pheromone pulses in plots treated with more point sources per hectare. There was also a positive correlation between the number of pulses recorded by the EAG and predicted concentration for plots treated with 1000 or 2000 dispensers/ha. These results give added support to our model of pheromone release and transport in treated apple orchards.     

Health and Safety Management within Small- and Medium-Sized Enterprises (SMEs) in Developing Countries: Study of Contextual Influences

Considerable attention has been focused on addressing construction health and safety risks in developed economies. Sadly, the same cannot be said of developing countries in Sub-Saharan Africa where accident figures are extremely high. The aim of this study is to examine the influence of the contextual environment within which Ghanaian construction small- and medium-sized enterprises (SMEs) manage occupational health and safety (OH&S). A questionnaire survey was administered to construction SMEs to better understand the health and safety management practices and associated problems followed up by field interviews to explore key issues identified by the survey. The results of the study highlight the institutional structure for implementing OH&S standards, prevailing economic climate, and extended family culture as challenges to the management of OH&S. The study identifies low literacy levels, low socioeconomic status of workers, owner/managers’ ignorance of their OH&S responsibilities, commitment to extended family obligations, and ineffective OH&S administration as key factors limiting the capacity of construction SMEs to manage OH&S effectively. The study concludes that effective institutional structure and an enabling socioeconomic environment are needed to enhance the OH&S performance of SMEs and advocates for more proactive OH&S management that take into consideration the work cultures of SMEs.     

High-density support matrices: Key to the deep borehole disposal of spent nuclear fuel

Deep (4-5 km) boreholes are emerging as a safe, secure, environmentally sound and potentially cost-effective option for disposal of high-level radioactive wastes, including plutonium. One reason this option has not been widely accepted for spent fuel is because stacking the containers in a borehole could create load stresses threatening their integrity with potential for releasing highly mobile radionuclides like ¹²⁹I before the borehole is filled and sealed. This problem can be overcome by using novel high-density support matrices deployed as fine metal shot along with the containers. Temperature distributions in and around the disposal are modelled to show how decay heat from the fuel can melt the shot within weeks of disposal to give a dense liquid in which the containers are almost weightless. Finally, within a few decades, this liquid will cool and solidify, entombing the waste containers in a base metal sarcophagus sealed into the host rock.     

Contributing factors in construction accidents

This overview paper draws together findings from previous focus group research and studies of 100 individual construction accidents. Pursuing issues raised by the focus groups, the accident studies collected qualitative information on the circumstances of each incident and the causal influences involved. Site based data collection entailed interviews with accident-involved personnel and their supervisor or manager, inspection of the accident location, and review of appropriate documentation. Relevant issues from the site investigations were then followed up with off-site stakeholders, including designers, manufacturers and suppliers. Levels of involvement of key factors in the accidents were: problems arising from workers or the work team (70% of accidents), workplace issues (49%), shortcomings with equipment (including PPE) (56%), problems with suitability and condition of materials (27%), and deficiencies with risk management (84%). Employing an ergonomics systems approach, a model is proposed, indicating the manner in which originating managerial, design and cultural factors shape the circumstances found in the work place, giving rise to the acts and conditions which, in turn, lead to accidents. It is argued that attention to the originating influences will be necessary for sustained improvement in construction safety to be achieved.