Water security through scarcity pricing and reverse osmosis: a system dynamics approach

Water supply and demand planning is often conducted independently of social and economic strategies. There are presently no comprehensive life-cycle approaches to modelling urban water balances that incorporate economic feedbacks, such as tariff adjustment, which can in turn create a financing capacity for investment responses to low reservoir levels. This paper addresses this gap, and presents a system dynamics model that augments the usual water utility representation of the physical linkages of water grids, by adding inter-connected feedback loops in tariff structures, demand levels and financing capacity. The model, applied in the south-east Queensland region in Australia, enables simulation of alternatives and analysis of stocks and flows around a grid or portfolio of bulk supplies including an increasing proportion of rain-independent desalination plants. Such rain-independent water production plants complement the rain-dependent sources in the region and can potentially offer indefinite water security at a price. The study also shows how an alternative temporary drought pricing regime not only defers costly bulk supply infrastructure but actually generates greater price stability than traditional pricing approaches. The model has implications for water supply planners seeking to pro-actively plan, justify and finance portfolios of rain-dependent and rain-independent bulk water supply infrastructure. Interestingly, the modelling showed that a temporary drought pricing regime not only lowers the frequency and severity of water insecurity events but also reduces the long-run marginal cost of water supply for the region when compared to traditional reactive planning approaches that focus on restrictions to affect demand in scarcity periods.

Resistance and resilience: Can the abrupt end of extreme drought reverse avifaunal collapse?

Aim: Climate change is expected to increase the frequency and intensity of extreme climatic events, such as severe droughts and intense rainfall periods. We explored how the avifauna of a highly modified region responded to a 13-year drought (the 'Big Dry'), followed by a two-year period of substantially higher than average rainfall (the 'Big Wet'). Location: Temperate woodlands in north central Victoria, Australia. Methods: We used two spatially extensive, long-term survey programmes, each of which was repeated three times: early and late in the Big Dry, and in the Big Wet. We compared species-specific changes in reporting rates between periods in both programmes to explore the resistance (the ability to persist during drought) and resilience (extent of recovery post-drought) of species to climate extremes. Results: There was a substantial decline in the reporting rates of 42-62% (depending on programme) of species between surveys conducted early and late in the Big Dry. In the Big Wet, there was some recovery, with 21-29% of species increasing substantially. However, more than half of species did not recover and 14-27% of species continued to decline in reporting rate compared with early on in the Big Dry. Species' responses were not strongly related to ecological traits. Species resistance to the drought was inversely related to resilience in the Big Wet for 20-35% of the species, while 76-78% of species with low resistance showed an overall decline across the study period. Conclusions: As declines occurred largely irrespective of ecological traits, this suggests a widespread mechanism is responsible. Species that declined the most during the Big Dry did not necessarily show the greatest recoveries. In already much modified regions, climate extremes such as extended drought will induce on-going changes in the biota. © 2014 John Wiley & Sons Ltd.

Does reverse causality explain the relationship between diet and depression?

BACKGROUND: Observational studies have repeatedly demonstrated relationships between habitual diet quality and depression. However, whilst reverse causality has not been the identified mechanism for these associations in prospective studies, the relationship between diet and depression is likely complex and bidirectional. Thus explicit investigation of the reverse causality hypothesis is warranted. METHODS: Data were drawn from the Personality and Total Health (PATH) Through Life Study, a longitudinal community survey following three age cohorts from Australia. Analyses evaluated the relationships between past depression and treatment, current depressive symptoms and dietary patterns. RESULTS: Individuals with current depression had lower scores on a healthy dietary pattern; however, those who had been previously depressed and sought treatment had higher scores on the healthy dietary pattern at the later baseline assessment. Moreover, those who had reported prior, but not current, depression also had lower scores on the western dietary pattern than those without prior depression, regardless of whether they had been previously treated for their symptoms. LIMITATIONS: Self-report data and possible recall bias limit our conclusions. CONCLUSIONS: In this study, prior depression was associated with better quality diets at the later time point. Thus, while current depression is associated with poorer dietary habits, a history of depression may prompt healthier dietary behaviours in the long term. Given the demonstrated relationships between diet quality and depressive illness, clinicians should advocate dietary improvement for their patients with depression and should not be pessimistic about the likelihood of adherence to such recommendations.

Integration of design for reverse logistics and harvesting of information: a research agenda

The literature is replete with treatises advocating the immense benefits of reverse logistics (RL) systems for organisations in terms of alleviating environmental concerns and enhancing the level of productivity. Nevertheless, implementing RL in organisations is fraught with complications with its success largely riding on fulfilling the requirements prescribed by the critical success factors (CSFs) of RL. Despite the voluminous body of knowledge on RL in the extant literature, operational aspects of RL have overshadowed some central strategic prerequisites for the success of RL systems. Drawing upon an integrative literature review, this paper provides an insight into different aspects of the implementation of RL practices. The central role of the integration of design for reverse logistics (DfRL) and harvesting of information (HoI) in the effective implementation of RL systems is then established and clarified through developing a conceptual framework. The paper concludes by putting forward an agenda for research.

Cancer risk among people with type 1 and type 2 diabetes: disentangling true associations, detection bias, and reverse causation

 OBJECTIVE: Evidence indicates an increased risk of certain cancers among people with type 2 diabetes. Evidence for rarer cancers and for type 1 diabetes is limited. We explored the excess risk of site-specific cancer incidence and mortality among people with type 1 and type 2 diabetes, compared with the general Australian population. RESEARCH DESIGN AND METHODS: Registrants of a national diabetes registry (953,382) between 1997 and 2008 were linked to national death and cancer registries. Standardized incidence and mortality ratios (SIRs/SMRs) are reported. RESULTS: For type 1 diabetes, significant elevated SIRs were observed for pancreas, liver, esophagus, colon and rectum (females only [F]), stomach (F), thyroid (F), brain (F), lung (F), endometrium, and ovary, and decreased SIRs were observed for prostate in males. Significantly increased SMRs were observed for pancreas, liver, and kidney (males only), non-Hodgkin's lymphoma, brain (F), and endometrium. For type 2 diabetes, significant SIRs were observed for almost all site-specific cancers, with highest SIRs observed for liver and pancreas, and decreased risks for prostate and melanoma. Significant SMRs were observed for liver, pancreas, kidney, Hodgkin's lymphoma, gallbladder (F), stomach (F), and non-Hodgkin's lymphoma (F). Cancer risk was significantly elevated throughout follow-up time but was higher in the first 3 months postregistration, suggesting the presence of detection bias and/or reverse causation. CONCLUSIONS: Type 1 and type 2 diabetes are associated with an excess risk of incidence and mortality for overall and a number of site-specific cancers, and this is only partially explained by bias. We suggest that screening for cancers in diabetic patients is important.

Reverse logistics in the construction industry

Reverse logistics in construction refers to the movement of products and materials from salvaged buildings to a new construction site. While there is a plethora of studies looking at various aspects of the reverse logistics chain, there is no systematic review of literature on this important subject as applied to the construction industry. Therefore, the objective of this study is to integrate the fragmented body of knowledge on reverse logistics in construction, with the aim of promoting the concept among industry stakeholders and the wider construction community. Through a qualitative meta-analysis, the study synthesises the findings of previous studies and presents some actions needed by industry stakeholders to promote this concept within the real-life context. First, the trend of research and terminology related with reverse logistics is introduced. Second, it unearths the main advantages and barriers of reverse logistics in construction while providing some suggestions to harness the advantages and mitigate these barriers. Finally, it provides a future research direction based on the review.

Culture shock and reverse culture shock: the moderating role of cultural intelligence in international students' adaptation

This study extends previous research by examining the role of cultural intelligence (CQ) in both culture shock and reverse culture shock. Specifically, this study asserts that CQ acts as a moderating mechanism that lessens the negative effects of both culture shock and reverse culture shock on psychological and sociocultural adaptation among international students. Two studies were conducted in Australia to test these assertions. Study 1 (n = 189) was participated in by new international students. An online survey was set up and disseminated. Results indicated that culture shock is significantly but negatively related to both psychological and sociocultural adaptation. In addition, results demonstrated that CQ moderates the relationship by lessening the impact of culture shock on students’ psychological and sociocultural adaptation. Study 2 (n = 123) was participated in by international students who had recently graduated and returned to their home countries. An online survey was also set up and disseminated. Results indicated that reverse culture shock is significantly but negatively related to both psychological and sociocultural adaptation. CQ also served as a moderator in lessening the impact of reverse culture shock on both forms of adaptation.

Barriers to implementing reverse logistics in South Australian construction organisations

Purpose - This paper aims to present a survey of the perceptions of the barriers to implementing reverse logistics (RL) practices in South Australian (SA) construction organisations. Despite the extensive research on forward logistics and RL, there is a paucity of studies that examine the barriers to implementing RL particularly within the Australian construction industry. This study builds on the ongoing research being undertaken by the authors, entitled “Designing for reverse logistics (DfRL) within the building life cycle: practices, drivers and barriers”, which is examining the best practices and drivers that could be used as a “road map” for developing appropriate solutions for the successful implementation of RL. Design/methodology/approach - Data were collected by utilising a triangulated data collection approach, a literature review and 49 questionnaires. The review of the literature identified 16 barriers to implementing RL. The quantitative survey data were subjected to descriptive and inferential statistics with correlation analysis to examine the relationships between different pairs of variables comprising RL’s critical barriers. Findings - The following barriers were indicated as most significant: lack of incorporation of salvaged materials by designers; regulation restrictions to usage of recovered materials and components; potential legal liabilities; higher costs; and longer-time association with deconstructing buildings. The least ranked barriers were mostly drawn from the operational and industrial categories as being: organisational lack of support for deconstruction due to incompatible design; lack of organisational support for deconstructing buildings due to higher health and safety risks; and inadequate skills and experience for deconstruction (operational). The industrial barrier was related to “higher costs of salvaged materials in comparison to virgin products”. Research limitations/implications - First, the reported findings are focussed on one study that used questionnaire surveys within the construction industry; therefore, the results may not be generalisable to other contexts. Further, studies should be conducted and extended to other industrial sectors beyond the construction industry. Second, the quantitative study (n 49) used a smaller sample, and the survey items were based on the review of the literature. Practical implications - The identified barriers could be used as a “road map” for the development of appropriate solutions for the successful implementation of RL, and to improve the environment-related decision-making processes of contractors. Originality/value - This study makes a contribution to the body of knowledge on the subject of RL within a previously unexplored SA context. In addition, the study provides some insights on the contributory effects of the barriers to the implementation of RL. It is the first work undertaken to determine the barriers to the adoption of RL within the SA construction industry.

Analysis of reverse logistics implementation practices by South Australian construction organisations

Purpose – A large number of benefits have been reported when reverse logistics (RL) is fully implemented in the construction industry. However, RL is yet to become common place in the construction sector, particularly in Australia. The particular sub-sector in which RL operates is small and weak and the remainder of the sector must embrace and accommodate it comfortably. Research is lacking on how to promoting RL in the construction industry. Very little has been done to identify the current practices that have the potential to promote RL industry-wide. The purpose of this paper is to identify the practices that work well in the sector, a strategy could be mapped out to promote RL to all stakeholders. Design/methodology/approach – In order to fill the above gap, the present study used a mixed method approach to gather and evaluate current practices and their potential to promote RL in South Australia’s construction industry. Practices that were identified using a comprehensive literature review were evaluated with a questionnaire survey and series of interviews involving construction professionals. Findings – The findings are that practices facilitating deconstruction is the most important, followed by practices facilitating the use of salvaged materials in new construction to promote RL in South Australia. Awareness of deconstruction benefits, challenges and procedures at the organisation level and facilities and services at industry level were associated with RL implementation. Availability of salvaged materials in the market was found to influence its use in new construction and as a consequence its demand. Designing for reverse logistics is another practice that could facilitate deconstruction and the onus of its promotion lies mainly with the designers. Research limitations/implications – This research was confined to one state in Australia. As such the generalisation to other states and other countries should be treated cautiously. Practical implications – The findings of this study can help inform the industry and its stakeholders on areas that they need to concentrate more on to make the South Australian construction industry a fully RL integrated one. To that end the authors propose some recommendations arising from the findings reported here. Originality/value – This study makes a contribution to the body of knowledge on reserve logistics within a previously unexplored South Australian context. In addition, the study provides valuable insights into the contribution of RL practices to the construction industry.

Hybrid threshold adaptable quantum secret sharing scheme with reverse Huffman-Fibonacci-tree coding

With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m-bonacci sequences to detect eavesdropping. Meanwhile, we encode m-bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications.

Drivers for adopting reverse logistics in the construction industry : a qualitative study

Purpose - The purpose of this paper is to investigate and analyse the perceptions of South Australian construction practitioners on drivers affecting the implementation of reverse logistics (RL). In this context, RL is defined as the process of moving goods from their typical final destination for the purpose of capturing value or ensuring proper disposal.

Design/methodology/approach - Semi-structured interviews were conducted with eight practitioners to collect data and the interview transcripts were analysed using the NVivo (version 10) package. Cluster analysis was used to cross-validate the findings and provide an in-depth insight into the findings.

Findings - The findings indicate that most of the drivers identified in earlier research are relevant for the construction industry. In addition, the study identified some new drivers that are categorised as "targeted demands by an exclusive clientele". These drivers were found to be complementary to the economic, environmental and social drivers as previously conceptualised. In addition, a set of factors affecting the strength of drivers that had been overlooked in previous studies emanated from the interview analysis. These include the type of project and the attributes of clients, both of which strongly affect the drivers of RL implementation in construction.

Research limitations/implications - The major limitations are the relatively small size of the sample of interviewees and having interviewees from one geographic area with specific socio-economic characteristics.

Practical implications - The identified drivers and the clustering of RL themes could be used by practitioners as a "road map" for the development of appropriate solutions to successfully promote RL within the construction industry. Organisational energies could thus be channelled towards the drivers that need the most improvement.

Originality/value - The study contributes to this research sphere by employing cluster analysis to customise and contextualise the drivers that were previously identified. The study goes beyond the extant literature by discovering the prominent effects of these drivers on the impact of targeted demands by an exclusive clientele. This could be of great value in terms of creating avenues for future investigations on the topic.

Silica fouling in high salinity waters in reverse osmosis desalination (sodium-silica system)

Silica fouling patterns in a sodium–silica system and the effect of pH on residual dissolved silica concentrations are reported. The unique chemical affinity between sodium and silica (SO4) prevented silica scale deposition on the membrane surface during reverse osmosis (RO) desalination. It was found that high concentrations of sodium in solutions depressed silica solubility to 81–84 mg L−1 for a maximum NaCl salinity of 60–65 g L−1. Using a range of membrane examination techniques, it was found that no silica scale formed on the RO membrane surfaces from NaCl solutions free from cations such as Ca, Al and Fe. This was considered to be the result of sodium ions acting as a barrier between polymeric silica and the membrane surface.

A qualitative examination of major barriers in implementation of reverse logistics within the South Australian construction sector

Despite extensive research on the benefits of reverse logistics (RL), it has yet to become commonplace in the construction industry. Furthermore, the uptake and number of studies on RL remains very limited within the Australian context and particularly related to the construction industry. This paper is aimed at filling that knowledge gap by employing an exploratory approach to examine the critical barriers faced by South Australian construction organizations in implementing RL practices. Semi-structured interviews and a ranking approach facilitated the treatment of qualitative data through quantitative coding using cloud-based applications. The research identified 12 barriers to RL implementation, four of them very significant according to the responses of the interviewees: the regulatory environment, additional costs involved, lack of recognition in the construction supply chain, and extra effort required. The study also explored their inter-relationships through the Co-occurrence Index. The study proposes some remedial measures for RL implementation in South Australia based on the barriers identified.

A dynamic pricing reverse auction-based resource allocation mechanism in cloud workflow systems

Market-oriented reverse auction is an efficient and cost-effective method for resource allocation in cloud workflow systems since it can dynamically allocate resources depending on the supply-demand relationship of the cloud market. However, during the auction the price of cloud resource is usually fixed, and the current resource allocation mechanisms cannot adapt to the changeable market properly which results in the low efficiency of resource utilization. To address such a problem, a dynamic pricing reverse auction-based resource allocation mechanism is proposed. During the auction, resource providers can change prices according to the trading situation so that our novel mechanism can increase the chances of making a deal and improve efficiency of resource utilization. In addition, resource providers can improve their competitiveness in the market by lowering prices, and thus users can obtain cheaper resources in shorter time which would decrease monetary cost and completion time for workflow execution. Experiments with different situations and problem sizes are conducted for dynamic pricing-based allocation mechanism (DPAM) on resource utilization and the measurement of Time∗Cost (TC). The results show that our DPAM can outperform its representative in resource utilization, monetary cost, and completion time and also obtain the optimal price reduction rates.