Removal of toxic arsenic and antimony from groundwater Spiro Tunnel Bulkhead in Park City Utah using colloidal iron hydroxide : comparison with reverse ssmosis

Verification testing of two model technologies in pilot scale to remove arsenic and antimony based on reverse osmosis and chemical coagulation/filtration systems was conducted in Spiro Tunnel Water Filtration Plant located in Park City, Utah, US. The source water was groundwater in abandoned silver mine, naturally contaminated by 60-80 ppb of arsenic and antimony below 10 ppb. This water represents one of the sources of drinking water for Park City and constitutes about 44% of the water supply. The failure to remove antimony efficiently by coagulation/filtration (only 4.4% removal rate) under design conditions is discussed in terms of the chemistry differences between Sb (III, V) and As (III, V). Removal of Sb(V) at pH > 7, using coagulation/filtration technology, requires much higher (50 to 80 times) concentration of iron (III) than As. The stronger adsorption of arsenate over a wider pH range can be explained by the fact that arsenic acid is tri-protic, whereas antimonic acid is monoprotic. This difference in properties of As(V) and Sb(V) makes antimony (V) more difficult to be efficiently removed in low concentrations of iron hydroxide and alkaline pH waters, especially in concentration of Sb < 10 ppb.

Relative entropy rate based design for linear hybrid system models

Hybrid system representations have been applied to many challenging modeling situations. In these hybrid system representations, a mixture of continuous and discrete states is used to capture the dominating behavioural features of a nonlinear, possible uncertain, model under approximation. Unfortunately, the problem of how to best design a suitable hybrid system model has not yet been fully addressed. This paper proposes a new joint state measurement relative entropy rate based approach for this design purpose. Design examples and simulation studies are presented which highlight the benefits of our proposed design approaches.

Interest rate caps : protection or paternalism

In a context where over-indebtedness and financial exclusion have been recognised as problems in Australia, it is undesirable that those who can least afford it, pay a high cost for short-term consumer credit. Evidence points to an increase in consumer debt in Australia and consequential over-indebtedness which has been shown to lead to a wide range of social problems.2 There is also evidence of financial exclusion, where consumers suffer a lack of access to mainstream financial services, and in Australia this is particularly the case with regard to access to safe and affordable credit.3 Financial exclusion can only exacerbate over-indebtedness, given that financially excluded, predominantly low income consumers , have been shown to turn to high cost credit to meet their short term credit needs. This is a problem that has been explored most recently in the Victorian Consumer Credit Review...

Is the contemporary era behind us?

The advent of new technologies, like personal computers and networking platforms, represents a series of events that have impacted on society as a whole as well as challenging the artworld to reconsider what is 'contemporary'.

An economic evaluation of the Safe Motherhood programme in Guangxi, China

Maternal and infant mortality is a global health issue with a significant social and economic impact. Each year, over half a million women worldwide die due to complications related to pregnancy or childbirth, four million infants die in the first 28 days of life, and eight million infants die in the first year. Ninety-nine percent of maternal and infant deaths are in developing countries. Reducing maternal and infant mortality is among the key international development goals. In China, the national maternal mortality ratio and infant mortality rate were reduced greatly in the past two decades, yet a large discrepancy remains between urban and rural areas. To address this problem, a large-scale Safe Motherhood Programme was initiated in 2000. The programme was implemented in Guangxi in 2003. Interventions in the programme included both demand-side and supply side-interventions focusing on increasing health service use and improving birth outcomes. Little is known about the effects and economic outcomes of the Safe Motherhood Programme in Guangxi, although it has been implemented for seven years. The aim of this research is to estimate the effectiveness and cost-effectiveness of the interventions in the Safe Motherhood Programme in Guangxi, China. The objectives of this research include: 1. To evaluate whether the changes of health service use and birth outcomes are associated with the interventions in the Safe Motherhood Programme. 2. To estimate the cost-effectiveness of the interventions in the Safe Motherhood Programme and quantify the uncertainty surrounding the decision. 3. To assess the expected value of perfect information associated with both the whole decision and individual parameters, and interpret the findings to inform priority setting in further research and policy making in this area. A quasi-experimental study design was used in this research to assess the effectiveness of the programme in increasing health service use and improving birth outcomes. The study subjects were 51 intervention counties and 30 control counties. Data on the health service use, birth outcomes and socio-economic factors from 2001 to 2007 were collected from the programme database and statistical yearbooks. Based on the profile plots of the data, general linear mixed models were used to evaluate the effectiveness of the programme while controlling for the effects of baseline levels of the response variables, change of socio-economic factors over time and correlations among repeated measurements from the same county. Redundant multicollinear variables were deleted from the mixed model using the results of the multicollinearity diagnoses. For each response variable, the best covariance structure was selected from 15 alternatives according to the fit statistics including Akaike information criterion, Finite-population corrected Akaike information criterion, and Schwarz.s Bayesian information criterion. Residual diagnostics were used to validate the model assumptions. Statistical inferences were made to show the effect of the programme on health service use and birth outcomes. A decision analytic model was developed to evaluate the cost-effectiveness of the programme, quantify the decision uncertainty, and estimate the expected value of perfect information associated with the decision. The model was used to describe the transitions between health states for women and infants and reflect the change of both costs and health benefits associated with implementing the programme. Result gained from the mixed models and other relevant evidence identified were synthesised appropriately to inform the input parameters of the model. Incremental cost-effectiveness ratios of the programme were calculated for the two groups of intervention counties over time. Uncertainty surrounding the parameters was dealt with using probabilistic sensitivity analysis, and uncertainty relating to model assumptions was handled using scenario analysis. Finally the expected value of perfect information for both the whole model and individual parameters in the model were estimated to inform priority setting in further research in this area.The annual change rates of the antenatal care rate and the institutionalised delivery rate were improved significantly in the intervention counties after the programme was implemented. Significant improvements were also found in the annual change rates of the maternal mortality ratio, the infant mortality rate, the incidence rate of neonatal tetanus and the mortality rate of neonatal tetanus in the intervention counties after the implementation of the programme. The annual change rate of the neonatal mortality rate was also improved, although the improvement was only close to statistical significance. The influences of the socio-economic factors on the health service use indicators and birth outcomes were identified. The rural income per capita had a significant positive impact on the health service use indicators, and a significant negative impact on the birth outcomes. The number of beds in healthcare institutions per 1,000 population and the number of rural telephone subscribers per 1,000 were found to be positively significantly related to the institutionalised delivery rate. The length of highway per square kilometre negatively influenced the maternal mortality ratio. The percentage of employed persons in the primary industry had a significant negative impact on the institutionalised delivery rate, and a significant positive impact on the infant mortality rate and neonatal mortality rate. The incremental costs of implementing the programme over the existing practice were US $11.1 million from the societal perspective, and US $13.8 million from the perspective of the Ministry of Health. Overall, 28,711 life years were generated by the programme, producing an overall incremental cost-effectiveness ratio of US $386 from the societal perspective, and US $480 from the perspective of the Ministry of Health, both of which were below the threshold willingness-to-pay ratio of US $675. The expected net monetary benefit generated by the programme was US $8.3 million from the societal perspective, and US $5.5 million from the perspective of the Ministry of Health. The overall probability that the programme was cost-effective was 0.93 and 0.89 from the two perspectives, respectively. The incremental cost-effectiveness ratio of the programme was insensitive to the different estimates of the three parameters relating to the model assumptions. Further research could be conducted to reduce the uncertainty surrounding the decision, in which the upper limit of investment was US $0.6 million from the societal perspective, and US $1.3 million from the perspective of the Ministry of Health. It is also worthwhile to get a more precise estimate of the improvement of infant mortality rate. The population expected value of perfect information for individual parameters associated with this parameter was US $0.99 million from the societal perspective, and US $1.14 million from the perspective of the Ministry of Health. The findings from this study have shown that the interventions in the Safe Motherhood Programme were both effective and cost-effective in increasing health service use and improving birth outcomes in rural areas of Guangxi, China. Therefore, the programme represents a good public health investment and should be adopted and further expanded to an even broader area if possible. This research provides economic evidence to inform efficient decision making in improving maternal and infant health in developing countries.

The effect of ocular surface conditions on blink rate and completeness

A healthy human would be expected to show periodic blinks, making a brief closure of the eyelids. Most blinks are spontaneous, occurring regularly with no external stimulus. However a reflex blink can occur in response to external stimuli such as a bright light, a sudden loud noise, or an object approaching toward the eyes. A voluntary or forced blink is another type of blink in which the person deliberately closes the eyes and the lower eyelid raises to meet the upper eyelid. A complete blink, in which the upper eyelid touches the lower eyelid, contributes to the health of ocular surface by providing a fresh layer of tears as well as maintaining optical integrity by providing a smooth tear film over the cornea. The rate of blinking and its completeness vary depending on the task undertaken during blink assessment, the direction of gaze, the emotional state of the subjects and the method under which the blink was measured. It is also well known that wearing contact lenses (both rigid and soft lenses) can induce significant changes in blink rate and completeness. It is been established that efficient blinking plays an important role in ocular surface health during contact lens wear and for improving contact lens performance and comfort. Inefficient blinking during contact lens wear may be related to a low blink rate or incomplete blinking and can often be a reason for dry eye symptoms or ocular surface staining. It has previously been shown that upward gaze can affect blink rate, causing it to become faster. In the first experiment, it was decided to expand on previous studies in this area by examining the effect of various gaze directions (i.e. upward gaze, primary gaze, downward gaze and lateral gaze) as well as head angle (recumbent position) on normal subjects’ blink rate and completeness through the use of filming with a high-speed camera. The results of this experiment showed that as the open palpebral aperture (and exposed ocular surface area) increased from downward gaze to upward gaze, the number of blinks significantly increased (p<0.04). Also, the size of closed palpebral aperture significantly increased from downward gaze to upward gaze (p<0.005). A weak positive correlation (R² = 0.18) between the blink rate and ocular surface area was found in this study. Also, it was found that the subjects showed 81% complete blinks, 19% incomplete blinks and 2% of twitch blinks in primary gaze, consistent with previous studies. The difference in the percentage of incomplete blinks between upward gaze and downward gaze was significant (p<0.004), showing more incomplete blinks in upward gaze. The findings of this experiment suggest that while blink rate becomes slower in downward gaze, the completeness of blinking is typically better, thereby potentially reducing the risk of tear instability. On the other hand, in upward gaze while the completeness of blinking becomes worse, this is potentially offset by increased blink frequency. In addition, blink rate and completeness were not affected by lateral gaze or head angle, possibly because these conditions have similar size of the open palpebral aperture compared with primary gaze. In the second experiment, an investigation into the changes in blink rate and completeness was carried out in primary gaze and downward gaze with soft and rigid contact lenses in unadapted wearers. Not surprisingly, rigid lens wear caused a significant increase in the blink rate in both primary (p<0.001) and downward gaze (p<0.02). After fitting rigid contact lenses, the closed palpebral aperture (blink completeness) did not show any changes but the open palpebral aperture showed a significant narrowing (p<0.04). This might occur from the subjects’ attempt to avoid interaction between the upper eyelid and the edge of the lens to minimize discomfort. After applying topical anaesthetic eye drops in the eye fitted with rigid lenses, the increased blink rate dropped to values similar to that before lens insertion and the open palpebral aperture returned to baseline values, suggesting that corneal and/or lid margin sensitivity was mediating the increased blink rate and narrowed palpebral aperture. We also investigated the changes in the blink rate and completeness with soft contact lenses including a soft sphere, double slab-off toric design and periballast toric design. Soft contact lenses did not cause any significant changes in the blink rate, closed palpebral aperture, open palpebral aperture and the percentage of incomplete blinks in either primary gaze or downward gaze. After applying anaesthetic eye drops, the blink rate reduced in both primary gaze and downward gaze, however this difference was not statistically significant. The size of the closed palpebral aperture and open palpebral aperture did not show any significant changes after applying anaesthetic eye drops. However it should be noted that the effects of rigid and soft contact lenses that we observed in these studies were only the immediate reaction to contact lenses and in the longer term, it is likely that these responses will vary as the eye adapts to the presence of the lenses.

Oxygen delivery through high-flow nasal cannulae increase end-expiratory lung volume and reduce respiratory rate in post-cardiac surgical patients

Background: High-flow nasal cannulae (HFNC) create positive oropharyngeal airway pressure but it is unclear how their use affects lung volume. Electrical impedance tomography (EIT) allows assessment of changes in lung volume by measuring changes in lung impedance. Primary objectives were to investigate the effects of HFNC on airway pressure (Paw) and end-expiratory lung volume (EELV), and to identify any correlation between the two. Secondary objectives were to investigate the effects of HFNC on respiratory rate (RR), dyspnoea, tidal volume and oxygenation; and the interaction between body mass index (BMI) and EELV. Methods: Twenty patients prescribed HFNC post-cardiac surgery were investigated. Impedance measures, Paw, PaO2/FiO2 ratio, RR and modified Borg scores were recorded first on low flow oxygen (nasal cannula or Hudson face mask) and then on HFNC. Results: A strong and significant correlation existed between Paw and end-expiratory lung impedance (EELI) (r=0.7, p<0.001). Compared with low flow oxygen, HFNC significantly increased EELI by 25.6% (95% CI 24.3, 26.9) and Paw by 3.0 cmH2O (95% CI 2.4, 3.7). RR reduced by 3.4 breaths per minute (95% CI 1.7, 5.2) with HFNC use, tidal impedance variation increased by 10.5% (95% CI 6.1, 18.3) and PaO2/FiO2 ratio improved by 30.6 mmHg (95% CI 17.9, 43.3). HFNC improved subjective dyspnoea scoring (p=0.023). Increases in EELI were significantly influenced by BMI, with larger increases associated with higher BMIs (p<0.001). Conclusions: This study suggests that HFNC improve dyspnoea and oxygenation by increasing both EELV and tidal volume, and are most beneficial in patients with higher BMIs.

Inferior field loss increases rate of falls in older adults with glaucoma

PURPOSE: To examine the visual predictors of falls and injurious falls among older adults with glaucoma. METHODS: Prospective falls data were collected for 71 community-dwelling adults with primary open-angle glaucoma, mean age 73.9 ± 5.7 years, for one year using monthly falls diaries. Baseline assessment of central visual function included high-contrast visual acuity and Pelli-Robson contrast sensitivity. Binocular integrated visual fields were derived from monocular Humphrey Field Analyser plots. Rate ratios (RR) for falls and injurious falls with 95% confidence intervals (CIs) were based on negative binomial regression models. RESULTS: During the one year follow-up, 31 (44%) participants experienced at least one fall and 22 (31%) experienced falls that resulted in an injury. Greater visual impairment was associated with increased falls rate, independent of age and gender. In a multivariate model, more extensive field loss in the inferior region was associated with higher rate of falls (RR 1.57, 95%CI 1.06, 2.32) and falls with injury (RR 1.80, 95%CI 1.12, 2.98), adjusted for all other vision measures and potential confounding factors. Visual acuity, contrast sensitivity, and superior field loss were not associated with the rate of falls; topical beta-blocker use was also not associated with increased falls risk. CONCLUSIONS: Falls are common among older adults with glaucoma and occur more frequently in those with greater visual impairment, particularly in the inferior field region. This finding highlights the importance of the inferior visual field region in falls risk and assists in identifying older adults with glaucoma at risk of future falls, for whom potential interventions should be targeted. KEY WORDS: glaucoma, visual field, visual impairment, falls, injury

An evaluation of the sustainability of agreements reached through mediations conducted by the dispute resolution centres of the Department of Justice and Attorney General, Queensland between 1999 to 2003

In 1990 the Dispute Resolution Centres Act, 1990 (Qld) (the Act) was passed by the Queensland Parliament. In the second reading speech for the Dispute Resolution Centres Bill on May 1990 the Hon Dean Wells stated that the proposed legislation would make mediation services available “in a non-coercive, voluntary forum where, with the help of trained mediators, the disputants will be assisted towards their own solutions to their disputes, thereby ensuring that the result is acceptable to the parties” (Hansard, 1990, 1718). It was recognised at that time that a method for resolving disputes was necessary for which “the conventional court system is not always equipped to provide lasting resolution” (Hansard, 1990, 1717). In particular, the lasting resolution of “disputes between people in continuing relationships” was seen as made possible through the new legislation; for example, “domestic disputes, disputes between employees, and neighbourhood disputes relating to such issues as overhanging tree branches, dividing fences, barking dogs, smoke, noise and other nuisances are occurring continually in the community” (Hansard, 1990, 1717). The key features of the proposed form of mediation in the Act were articulated as follows: “attendance of both parties at mediation sessions is voluntary; a party may withdraw at any time; mediation sessions will be conducted with as little formality and technicality as possible; the rules of evidence will not apply; any agreement reached is not enforceable in any court; although it could be made so if the parties chose to proceed that way; and the provisions of the Act do not affect any rights or remedies that a party to a dispute has apart from the Act” (Hansard, 1990, 1718). Since the introduction of the Act, the Alternative Dispute Resolution Branch of the Queensland Department of Justice and Attorney General has offered mediation services through, first the Community Justice Program (CJP), and then the Dispute Resolution Centres (DRCs) for a range of family, neighbourhood, workplace and community disputes. These services have mirrored those available through similar government agencies in other states such as the Community Justice Centres of NSW and the Victorian Dispute Resolution Centres. Since 1990, mediation has become one of the fastest growing forms of alternative dispute resolution (ADR). Sourdin has commented that "In addition to the growth in court-based and community-based dispute resolution schemes, ADR has been institutionalised and has grown within Australia and overseas” (2005, 14). In Australia, in particular, the development of ADR service provision “has been assisted by the creation and growth of professional organisations such as the Leading Edge Alternative Dispute Resolvers (LEADR), the Australian Commercial Dispute Centres (ACDC), Australian Disputes Resolution Association (ADRA), Conflict Resolution Network, and the Institute of Arbitrators and Mediators Australia (IAMA)” (Sourdin, 2005, 14). The increased emphasis on the use of ADR within education contexts (particularly secondary and tertiary contexts) has “also led to an increasing acceptance and understanding of (ADR) processes” (Sourdin, 2005, 14). Proponents of the mediation process, in particular, argue that much of its success derives from the inherent flexibility and creativity of the agreements reached through the mediation process and that it is a relatively low cost option in many cases (Menkel-Meadow, 1997, 417). It is also accepted that one of the main reasons for the success of mediation can be attributed to the high level of participation by the parties involved and thus creating a sense of ownership of, and commitment to, the terms of the agreement (Boulle, 2005, 65). These characteristics are associated with some of the core values of mediation, particularly as practised in community-based models as found at the DRCs. These core values include voluntary participation, party self-determination and party empowerment (Boulle, 2005, 65). For this reason mediation is argued as being an effective approach to resolving disputes, that creates a lasting resolution of the issues. Evaluation of the mediation process, particularly in the context of the growth of ADR, has been an important aspect of the development of the process (Sourdin, 2008). Writing in 2005 for example, Boulle, states that “although there is a constant refrain for more research into mediation practice, there has been a not insignificant amount of mediation measurement, both in Australia and overseas” (Boulle, 2005, 575). The positive claims of mediation have been supported to a significant degree by evaluations of the efficiency and effectiveness of the process. A common indicator of the effectiveness of mediation is the settlement rate achieved. High settlement rates for mediated disputes have been found for Australia (Altobelli, 2003) and internationally (Alexander, 2003). Boulle notes that mediation agreement rates claimed by service providers range from 55% to 92% (Boulle, 2005, 590). The annual reports for the Alternative Dispute Resolution Branch of the Queensland Department of Justice and Attorney-General considered prior to the commencement of this study indicated generally achievement of an approximate settlement figure of 86% by the Queensland Dispute Resolution Centres. More recently, the 2008-2009 annual report states that of the 2291 civil dispute mediated in 2007-2008, 86% reached an agreement. Further, of the 2693 civil disputes mediated in 2008-2009, 73% reached an agreement. These results are noted in the report as indicating “the effectiveness of mediation in resolving disputes” and as reflecting “the high level of agreement achieved for voluntary mediations” (Annual Report, 2008-2009, online). Whilst the settlement rates for the DRCs are strong, parties are rarely contacted for long term follow-up to assess whether agreements reached during mediation lasted to the satisfaction of each party. It has certainly been the case that the Dispute Resolution Centres of Queensland have not been resourced to conduct long-term follow-up assessments of mediation agreements. As Wade notes, "it is very difficult to compare "success" rates” and whilst “politicians want the comparison studies (they) usually do not want the delay and expense of accurate studies" (1998, 114). To date, therefore, it is fair to say that the efficiency of the mediation process has been evaluated but not necessarily its effectiveness. Rather, the practice at the Queensland DRCs has been to evaluate the quality of mediation service provision and of the practice of the mediation process. This has occurred, for example, through follow-up surveys of parties' satisfaction rates with the mediation service. In most other respects it is fair to say that the Centres have relied on the high settlement rates of the mediation process as a sign of the effectiveness of mediation (Annual Reports 1991 - 2010). Research of the mediation literature conducted for the purpose of this thesis has also indicated that there is little evaluative literature that provides an in-depth analysis and assessment of the longevity of mediated agreements. Instead evaluative studies of mediation tend to assess how mediation is conducted, or compare mediation with other conflict resolution options, or assess the agreement rate of mediations, including parties' levels of satisfaction with the service provision of the dispute resolution service provider (Boulle, 2005, Chapter 16).

Digital reflections on learning : a monograph by students of Digital Pedagogies, Semester 2, 2011

Learning a digital tool is often a hidden process. We tend to learn new tools in a bewildering range of ways. Formal, informal, structured, random, conscious, unconscious, individual, group strategies, may all play a part, but are often lost to us in the complex and demanding processes of learning. But when we reflect carefully on the experience, some patterns and surprising techniques emerge. This monograph presents the thinking of four students in MDN642, Digital Pedagogies, where they have deliberately reflected on the mental processes at work as they learnt a digital technology of their choice.