Engineered ecosystem for sustainable on-site wastewater treatment

A Pilot-Scale Engineered Ecosystem (PSEE) operated for over two years in sub-tropical conditions, produced an effluent with COD (median 38 mg/L) and TSS (median 3 mg/L) levels comparable to that required by the AS/NZS 1547:2000 Onsite Domestic Wastewater Management standard. Only partial nitrification was achieved as dissimilatory nitrate reduction to ammonia occurred; however the level of NH4-N was reduced by 75% and total inorganic nitrogen by 53%. Phosphorus was not removed by the system due to the lack of regular sludge removal. Mass balances around the system showed that bacteria removed 36% of the influent nitrogen and 76% of the influent COD. Algae and plants were shown to remove 5% of the influent nitrogen, and 6% of the influent phosphorus. Challenges in developing a sustainable on-site wastewater treatment system were largely met by minimising chemical, energy and labour inputs, eliminating the need for frequent sludge handling, and creating an effluent quality suitable for re-use in non-potable applications. However, the sludge removal from the system needs to be adequately managed to avoid excessive accumulation as this can cause a range of negative impacts.

Impact of on-site testing for maternal syphilis on treatment delays, treatment rates, and perinatal mortality in rural South Africa: a randomised controlled trial

Background: Syphilis remains a significant cause of preventable perinatal death in developing countries with many women remaining untested and thus untreated. Syphilis testing in the clinic (on-site testing) may be a useful strategy to overcome this. We studied the impact of on-site syphilis testing on treatment delays and rates, and perinatal mortality. Methods: We conducted a cluster randomised controlled trial among seven pairs of primary healthcare clinics in rural South Africa, comparing on-site testing complemented by laboratory confirmation versus laboratory testing alone. Intervention clinics used the on-site test conducted by primary care nurses, with results and treatment available within an hour. Control clinics sent blood samples to the provincial laboratory, with results returned 2 weeks later. Results: Of 7134 women seeking antenatal care with available test results, 793 (11.1%) tested positive for syphilis. Women at intervention clinics completed treatment 16 days sooner on average (95% confidence interval: 11 to 21), though there was no significant difference in the proportion receiving adequate treatment at intervention (64%) and control (69%) clinics. There was also no significant difference in the proportion experiencing perinatal loss (3.3% v 5.1%; adjusted risk difference: -0.9%; 95% Cl -4.4 to 2.7). Conclusions: Despite reducing treatment delays, the addition of on-site syphilis testing to existing laboratory testing services did not lead to higher treatment rates or reduce perinatal mortality. However on-site testing for syphilis may remain an important option for improving antenatal care in settings where laboratory facilities are not available.

Ferromagnetism, paramagnetism, and a Curie-Weiss metal in an electron-doped Hubbard model on a triangular lattice

Motivated by the unconventional properties and rich phase diagram of NaxCoO2 we consider the electronic and magnetic properties of a two-dimensional Hubbard model on an isotropic triangular lattice doped with electrons away from half-filling. Dynamical mean-field theory (DMFT) calculations predict that for negative intersite hopping amplitudes (t < 0) and an on-site Coulomb repulsion, U, comparable to the bandwidth, the system displays properties typical of a weakly correlated metal. In contrast, for t > 0 a large enhancement of the effective mass, itinerant ferromagnetism, and a metallic phase with a Curie-Weiss magnetic susceptibility are found in a broad electron doping range. The different behavior encountered is a consequence of the larger noninteracting density of states (DOS) at the Fermi level for t > 0 than for t < 0, which effectively enhances the mass and the scattering amplitude of the quasiparticles. The shape of the DOS is crucial for the occurrence of ferromagnetism as for t > 0 the energy cost of polarizing the system is much smaller than for t < 0. Our observation of Nagaoka ferromagnetism is consistent with the A-type antiferromagnetism (i.e., ferromagnetic layers stacked antiferromagnetically) observed in neutron scattering experiments on NaxCoO2. The transport and magnetic properties measured in NaxCoO2 are consistent with DMFT predictions of a metal close to the Mott insulator and we discuss the role of Na ordering in driving the system towards the Mott transition. We propose that the Curie-Weiss metal phase observed in NaxCoO2 is a consequence of the crossover from a bad metal with incoherent quasiparticles at temperatures T > T-* and Fermi liquid behavior with enhanced parameters below T-*, where T-* is a low energy coherence scale induced by strong local Coulomb electron correlations. Our analysis also shows that the one band Hubbard model on a triangular lattice is not enough to describe the unusual properties of NaxCoO2 and is used to identify the simplest relevant model that captures the essential physics in NaxCoO2. We propose a model which allows for the Na ordering phenomena observed in the system which, we propose, drives the system close to the Mott insulating phase even at large dopings.

A cohort study of early neurological consultation by telemedicine on the care of neurological inpatients

Objectives: To find out the effect of early neurological consultation using a real time video link on the care of patients with neurological symptoms admitted to hospitals without neurologists on site. Methods: A cohort study was performed in two small rural hospitals: Tyrone County Hospital (TCH), Omagh, and Erne Hospital, Enniskillen. All patients over 12 years of age who had been admitted because of neurological symptoms, over a 24 week period, to either hospital were studied. Patients admitted to TCH, in addition to receiving usual care, were offered a neurological consultation with a neurologist 120 km away at the Neurology Department of the Royal Victoria Hospital, Belfast, using a real time video link. The main outcome measure was length of hospital stay; change of diagnosis, mortality at 3 months, inpatient investigation, and transfer rate and use of healthcare resources within 3 months of admission were also studied. Results: Hospital stay was significantly shorter for those admitted to TCH (hazard ratio 1.13; approximate 95% Cl 1.003 to 1.282; p = 0.045). No patients diagnosed by the neurologist using the video link subsequently had their diagnosis changed at follow up. There was no difference in overall mortality between the groups. There were no differences in the use of inpatient hospital resources and medical services in the follow up period between TCH and Erne patients. Conclusions: Early neurological assessment reduces hospital stay for patients with neurological conditions outside of neurological centres. This can be achieved safely at a distance using a real time video link.

The Environment and the Selection of Aquaculture Species and Systems: An Economic Analysis

Environmental conditions play a significant role in the economic success of aquaculture. This article classifies environmental factors in a way that facilitates economic analysis of their implications for the selection of aquaculture species and systems. The implication of on-farm as on-site environmental conditions for this selection are considered first using profit-possibility frontiers and taking into account the biological law of environmental tolerance. However, in selecting, recommending and developing aquaculture species and systems, it is often unrealistic to assume the degree of managerial efficiency implied by the profit-possibility function. It is appropriate to take account of the degree of managerial inefficiency that actually exists, not all of which may be capable of being eliminated. Furthermore, experimental R&D should be geared to on-farm conditions, and the variability of these conditions needs to be taken into account. Particularly in shared water bodies, environmental spillovers between aquaculturalists can be important and as shown theoretically, can influence the socially optimal selection of aquaculture species and systems. Similarly, aquaculture can have environmental consequences for the rest of the community. The social economic implications of this for the selection of aquaculture species and systems are analyzed. Some paradoxical results are obtained. For example, if the quality of social governance of aquaculture is poor, aquaculture species and systems that cause a slow rate of environmental deterioration may be socially less satisfactory than those that cause a rapid rate of such deterioration. Socially optimal choice of aquaculture species and systems depends not only on their biophysical characteristics and market conditions but also on the prevailing state of governance of aquaculture. Failure to consider the last aspect can result in the introduction of new aquaculture species (and systems) doing more social harm than good.

Wildlife-based tourism & increased support for nature conservation financially and otherwise: evidence from sea-turtle ecotourism at Mon Repos

The arguments of most conservationists supporting ecotourism have been based on the view that it is environmentally friendly as a resource-use and that receipts from it can counter demands to use the natural resources involved for more extractive economic purposes. But wildlife-based ecotourism can also have positive impacts in itself on the willingness of tourists to pay for wildlife conservation, strengthen the pro-conservation attitudes of tourists, and foster personal actions by them that contribute to wildlife conservation. These aspects are explored in this article on the basis of a survey of tourists visiting Mon Repos Beach near Bundaberg, Queensland, for the purpose of watching marine turtles. The results enable several of the conservation impacts of this experience on tourists to be quantified, and highlight important relationships between specific socio-economic variables and the willingness of tourists to pay for the protection of sea turtles. Furthermore, it is shown that the on-site experiences of ecotourists have positive impacts on the willingness of tourists to pay for the conservation of wildlife, and that willingness to pay is sensitive to whether or not wildlife is seen. It is suggested that in situ ecotourism is likely to be a more powerful force for fostering pro-conservation attitudes and actions among visitors than ex situ wildlife-based tourism in aquaria and zoos.

A cross-sectional study of the association between Heberden's nodes, radiographic osteoarthritis of the hands, grip strength, disability and pain

Objective: To describe the associations between hand osteoarthritis (OA), pain and disability in males and females and to further validate the Australian/Canadian CA hand index (AUSCAN LK3.0). Design: Cross-sectional study of 522 subjects from 101 Tasmanian families (males N=174, females N=348). Hand OA was assessed by two observers using the Altman atlas for joint space narrowing and osteophytes at distal interphalangeal and first carpometacarpal joints as well as a score for Heberden's nodes based on hand photography. Hand pain and function were assessed by the AUSCAN LK3.0 and grip strength by dynamometry in both hands on two occasions. Results: The prevalence of hand CA was high in this sample at 44-71% (depending on site). Pain and dysfunction increased with age while grip strength decreased (all P <0.001). All three measures were markedly worse in women, even after taking the severity of arthritis into account. Hand CA explained 5.7-10% of the variation in function, grip strength and pain scores, even after adjustment for age and sex. Further adjustment suggested that the osteoarthritic associations with function and grip strength were largely mediated by pain. Severity of disease was more strongly associated with these scores than presence or absence. Lastly, the AUSCAN LK3.0 showed a comparable association to grip strength with structural damage providing further evidence of index validity. Conclusions: Hand CA at these two sites makes substantial contributions to hand function, strength and pain. The associations with function and strength measures appear mediated by pain. Gender differences in all three measures persist after adjustment for variation in age and CA severity indicating that factors apart from radiographic disease are responsible. (C) 2001 OsteoArthritis Research Society International.

The treatment of domestic wastewater using small-scale vermicompost filter beds

The aim of this study is to quantity the effect of filter bed depth and solid waste inputs on the performance of small-scale vermicompost filter beds that treat the soluble contaminants within domestic wastewater. The study also aims to identify environmental conditions within the filters by quantifying the oxygen content and pH of wastewater held within it. Vermicompost is being utilised within commercially available on-site domestic waste treatment systems however, there are few reported studies that have examined this medium for the purpose of wastewater treatment. Three replicate small-scale reactors were designed to enable wastewater sampling at five reactor depths in 10-cm intervals. The surface of each reactor received household solid organic waste and 1301 m(-2) per day of raw domestic wastewater. The solid waste at the filter bed surface leached oxygen demand into the wastewater flowing through it. The oxygen demand was subsequently removed in lower reactor sections. Both nitrification and denitrification occurred in the bed. The extent of denitrification was a function of BOD leached from the solid waste. The environmental conditions measured within the bed were found to be suitable for earthworms living within them. The study identified factors that will affect the performance and application of the vermicompost filtration technology. (C) 2004 Elsevier B.V. All rights reserved.

Multisite, quality-improvement collaboration to optimise cardiac care in Queensland public hospitals

Objective: To evaluate changes in quality of in-hospital care of patients with either acute coronary syndromes (ACS) or congestive heart failure (CHF) admitted to hospitals participating in a multisite quality improvement collaboration. Design: Before-and-after study of changes in quality indicators measured on representative patient samples between June 2001 and January 2003. Setting: Nine public hospitals in Queensland. Study populations: Consecutive or randomly selected patients admitted to study hospitals during the baseline period (June 2001 to January 2002; n = 807 for ACS, n = 357 for CHF) and post-intervention period (July 2002 to January 2003; n = 717 for ACS, n = 220 for CHF). Intervention: Provision of comparative baseline feedback at a facilitative workshop combined with hospital-specific quality-improvement interventions supported by on-site quality officers and a central program management group. Main outcome measure: Changes in process-of-care indicators between baseline and post-intervention periods. Results: Compared with baseline, more patients with ACS in the post-intervention period received therapeutic heparin regimens (84% v 72%; P < 0.001), angiotensin-converting enzyme inhibitors (64% v 56%; P = 0.02), lipid-lowering agents (72% v 62%; P < 0.001), early use of coronary angiography (52% v 39%; P < 0.001), in-hospital cardiac counselling (65% v 43%; P < 0.001), and referral to cardiac rehabilitation (15% v 5%; P < 0.001). The numbers of patients with CHF receiving β-blockers also increased (52% v 34%; P < 0.001), with fewer patients receiving deleterious agents (13% v 23%; P = 0.04). Same-cause 30-day readmission rate decreased from 7.2% to 2.4% (P = 0.02) in patients with CHF. Conclusion: Quality-improvement interventions conducted as multisite collaborations may improve in-hospital care of acute cardiac conditions within relatively short time frames.

Characterizing the physical and chemical properties of a vermicompost filter bed

Vermicompost filtration is a new on-site waste treatment system. Consequently, little is known about the filter medium properties. The aim of this preliminary study was to quantify physical and compositional properties of vermicompost filter beds that had been used to treat domestic solid organic waste and wastewater. This paper presents the trials performed on pilot-scale reactors filled with vermicompost from a full-scale vermicompost filtration system. Household solid organic waste and raw wastewater at the rate of 130 L/m(2)/d was applied to the reactor bed surface over a four-month period. It was found that fresh casts laid on the bed surface had a BOD of 1290 mg/g VS while casts buried to a depth of 10 cm had a BOD of 605 mg/g VS. Below this depth there was little further biodegradation of earthworm casts despite cast ages of up to five years. Solid material in the reactor accounted for only 7-10% of the reactor volume. The total voidage comprised of large free-draining pores, which accounted for 15-20% of the reactor volume and 60-70% micropores, able to hold up water against gravity. It was shown that water could flow through the medium micropores and macropores following a wastewater application. The wastewater flow characteristics were modeled by a two-region model based on the Richards Equation, an equation used to describe porous spatially heterogeneous materials.

Process, performance, and pollution potential: A review of septic tank-soil absorption systems

On-site wastewater treatment and dispersal systems (OWTS) are used in non-sewered populated areas in Australia to treat and dispose of household wastewater. The most common OWTS in Australia is the septic tank-soil absorption system (SAS) - which relies on the soil to treat and disperse effluent. The mechanisms governing purification and hydraulic performance of a SAS are complex and have been shown to be highly influenced by the biological zone (biomat) which develops on the soil surface within the trench or bed. Studies suggest that removal mechanisms in the biomat zone, primarily adsorption and filtering, are important processes in the overall purification abilities of a SAS. There is growing concern that poorly functioning OWTS are impacting upon the environment, although to date, only a few investigations have been able to demonstrate pollution of waterways by on-site systems. In this paper we review some key hydrological and biogeochemical mechanisms in SAS, and the processes leading to hydraulic failure. The nutrient and pathogen removal efficiencies in soil absorption systems are also reviewed, and a critical discussion of the evidence of failure and environmental and public health impacts arising from SAS operation is presented. Future research areas identified from the review include the interactions between hydraulic and treatment mechanisms, and the biomat and sub-biomat zone gas composition and its role in effluent treatment.

Minimal disease activity for rheumatoid arthritis: A preliminary definition

Agreement on response criteria in rheumatoid arthritis (RA) has allowed better standardization and interpretation of clinical trial reports. With recent advances in therapy, the proportion of patients achieving a satisfactory state of minimal disease activity (MDA) is becoming a more important measure with which to compare different treatment strategies. The threshold for MDA is between high disease activity and remission and, by definition, anyone in remission will also be in MDA. True remission is still rare in RA; in addition, the American College of Rheumatology definition is difficult to apply in the context of trials. Participants at OMERACT 6 in 2002 agreed on a conceptual definition of minimal disease activity (MDA): "that state of disease activity deemed a useful target of treatment by both the patient and the physician, given current treatment possibilities and limitations." To prepare for a preliminary operational definition of MDA for use in clinical trials, we asked rheumatologists to assess 60 patient profiles describing real RA patients seen in routine clinical practice. Based on their responses, several candidate definitions for MDA were designed and discussed at the OMERACT 7 in 2004. Feedback from participants and additional on-site analyses in a cross-sectional database allowed the formulation of 2 preliminary, equivalent definitions of MDA: one based on the Disease Activity Score 28 (DAS28) index, and one based on meeting cutpoints in 5 out the 7 WHO/ILAR core set measures. Researchers applying these definitions first need to choose whether to use the DAS28 or the core set definition, because although each selects a similar proportion in a population, these are not always the same patients. In both MDA definitions, an initial decision node places all patients in MDA who have a tender joint count of 0 and a swollen joint count of 0, and an erythrocyte sedimentation rate (ESR) no greater than 10 mm. If this condition is not met: center dot The DAS28 definition places patients in MDA when DAS28

Efffluent flux prediction in variably saturated soil zones within a septic tank-soil absorption trench

The treatment and hydraulic mechanisms in a septic tank-soil absorption system ( SAS) are highly influenced by the clogging layer or biomat zone which develops on bottom and lower sidewall surfaces within the trench. Flow rates through the biomat and sub-biomat zones are governed largely by the biomat hydraulic properties (resistance and hydraulic conductivity) and the unsaturated hydraulic conductivity of the underlying soil. One- and 2-dimensional models were used to investigate the relative importance of sidewall and vertical flow rates and pathways in SAS. Results of 1-dimensional modelling show that several orders of magnitude variation in saturated hydraulic conductivity (Ks) reduce to a 1 order of magnitude variation in long-term flow rates. To increase the reliability of prediction of septic trench hydrology, HYDRUS-2D was used to model 2-dimensional flow. In the permeable soils, under high trench loading, effluent preferentially flowed in the upper region of the trench where no resistant biomat was present (the exfiltration zone). By comparison, flow was more evenly partitioned between the biomat zones and the exfiltration zones of the low permeability soil. An increase in effluent infiltration corresponded with a greater availability of exfiltration zone, rather than a lower resistance of biomat. Results of modelling simulations demonstrated the important role that a permeable A horizon may play in limiting surface surcharge of effluent under high trench hydraulic loading.

Fostering professional development through integrating work and formal learning

The Undergraduate Site Learning Program (USLP) is an innovative work-based learning program that addresses the call to develop a broader set ofattributes in engineering graduates. Unlike cooperative education programs, site learning can give students full academic credit for their placement without extending the duration of the degree through the use of an innovative learning alignment model. A cenrralpart ofthis program is a unique course entitled Professional Development in which students articulate and reflect upon the lessons they leom while on placement in industry. Students spend the bulk ofa semester on-site often in remote locations, which requires a flexible approach to course operation and fosters independent learning. Thus the USLP challenges both staff and students and produces outcomes that bofh the alumni and industry value.