A note on the concentrations and bioavailability of selected metals in sediments of Richards Bay Harbour, South Africa

Sediments are considered to be the ultimate sink for most contaminants and therefore pose the highest risk to these aquatic environments. This paper presents the levels of metals in sediments from Richards Bay Harbour, 20 years after the construction of the harbour and studied spatial and temporal, as well as the proportion of the bioavailable metal fraction. Sediment samples were collected from nine sites in Richards Bay Harbour. Sequential extractions of metals were carried out and samples were analysed for aluminium, chromium, copper, iron, manganese and zinc. Metal concentrations in sediment samples varied only slightly between seasons but showed significant spatial variation, which was significantly correlated to sediment particle size composition. Highest metal concentrations were found in sites with substrata dominated by fine mud. Manganese and Zn had more than 50% of this concentrated in the easily reducible fractions. Zinc concentrations were not elevated when compared to historic data. More than 70% of Cr was concentrated in the inert fractions nevertheless concentrations recorded at some sites were still above action levels when considering only the bioavailable fractions. Keywords: sediments, metals, bioavailability, sediment composition, Richards Bay Harbour Water SA Vol. 31(4) 2005: 589-59

My Phone and Me: Understanding People's Receptivity to Mobile Notifications

Notifications are extremely beneficial to users, but they often demand their attention at inappropriate moments. In this paper we present an in-situ study of mobile interruptibility focusing on the effect of cognitive and physical factors on the response time and the disruption perceived from a notification. Through a mixed method of automated smartphone logging and experience sampling we collected 10372 in-the-wild notifications and 474 questionnaire responses on notification perception from 20 users. We found that the response time and the perceived disruption from a notification can be influenced by its presentation, alert type, sender-recipient relationship as well as the type, completion level and complexity of the task in which the user is engaged. We found that even a notification that contains important or useful content can cause disruption. Finally, we observe the substantial role of the psychological traits of the individuals on the response time and the disruption perceived from a notification

Functional health state description and valuation by people aged 65 and over:a pilot study

Abstract Background Assessing quality of life among the elderly is a complex and multifaceted issue. Elderly people might find valuing and describing their personal experience of quality of life (QoL) demanding and cumbersome. This study therefore sought to determine the feasibility of administering two questionnaires in two samples of elderly people. Methods A preference-based instrument (EQ-5D + C) and a currently achieved functioning questionnaire (CAF) were utilized. Two pilot studies were performed. The first was performed in South Africa (n = 30), designed to test whether elderly respondents could complete and understand the two questionnaires and also to indicate which valuation method, visual analogue scale or time trade off they preferred. A second pilot study was performed in the Netherlands (n = 30), designed to investigate the use of both questionnaires in determining quality of life and health state valuations in a Dutch sample of elderly. Results Seventy percent of the South African respondents indicated that they preferred the visual analogue scale (VAS) method, when compared to the time trade-off (TTO). In both the South African and the Dutch pilot studies, the respondents, with different dependency levels, were able to use both questionnaires to determine health state descriptions and valuations. When ranking the profiles from fewer to more problems, the EQ-5D + C exhibits a gradual downwards trend, with a maximum of 100 and minimum VAS value of 41. The CAF also exhibits a gradual downwards trend, with a maximum of 1.00 and minimum VAS value of 36. Conclusions The results indicate that individuals from different parts of the world are able to complete, describe, and value the questionnaires. It is our recommendation that a comprehensive study should be done, which includes both the EQ-5D + C questionnaire and the CAF questionnaire, since the two questionnaires have proven to be feasible in providing information on quality of life and well-being of elderly people

How do incumbent firms innovate their business models for the circular economy? Identifying micro‐foundations of dynamic capabilities

The circular economy is promoted as a contributor to sustainable development; however, the process of circular business model innovation remains under-explored to date, hindering its implementation. Dynamic capabilities research provides a theoretical perspective to explore how incumbent firms can innovate in rapidly changing environments. An abductive qualitative research is done through an exploratory multiple case study on 10 incumbents that implemented a circular business model innovation. We identify 26 practices, aggregated in 12 micro-foundations of the dynamic capabilities of sensing, seizing, and reconfiguring. By integrating the few empirical studies characterizing dynamic capabilities for sustainability-oriented business model innovation, we offer a comprehensive framework of 33 practices. This study proposes that the most relevant practices for circular business model innovation processes are adopting a lifecycle perspective, employing sustainability-oriented instruments, ideating sustainable value propositions, developing a sustainability strategy and culture, and engaging and coordinating stakeholders in the business ecosystem. We also suggest seven particularly relevant practices for long-term business model transformations (e.g., top management commitment), four for innovations focused on short and medium loops of the circular economy (e.g., early customer engagement), and four for long loops (e.g., business ecosystem coordination). This study corroborates and expands recent research on dynamic capabilities for sustainability-oriented innovation and provides practitioners with a set of 33 skills, processes, procedures, and activities to be prioritized to successfully innovate their business models for the circular economy

Ultimate producer responsibility for e-waste management–A proposal for just transition in the circular economy based on the case of used European electronic equipment exported to Nigeria

Used European electric and electronic equipment (UEEE) has multiple use cycles in various countries, including Nigeria. Although the EU-Nigeria e-waste trade is illegal under EU and Nigerian law, previous research shows that some imported equipment is only fit for disposal. Imported UEEE has a short lifespan. Such European e-waste exports imported to Nigeria have sustainability and circularity implications for both places and raise questions about justice and equity. Using a transdisciplinary approach, we identify existing practices and challenges in Nigeria and co-create actionable solutions towards a sustainable, circular and fairness-driven UEEE and e-waste value chain. We find current extended producer responsibility (EPR) does not focus on the entire global value chain, is linear, and lacks transparency, accountability, and consideration for spatial equity. To overcome these shortcomings, we propose ultimate producer responsibility (UPR). UPR aids sustainability and circularity transition while paying attention to justice and equity. The research adds global and social dimensions to the European circular economy (CE), otherwise primarily focused on national material cycles

Developing and improving quality efficiency in the South Africa energy industry

Businesses today need to be more effective and efficient in order to design the best products and provide outstanding services to their customers. The purpose of this research is to develop and improve quality efficiency while sustaining continuous improvement at a South African Energy provider's Mpumalanga plant, which is one of the nine regions in South Africa. Accomplishing quality efficiency is challenging, as customers expect quality of service at all times. In general an organisation's or a business's success depends on the reliability of delivering electricity. Therefore the South African Energy provider should be able and capable to deliver electricity at all times. Current research results revealed that: (1) organisations need to do more to raise quality awareness and inform other employees about the quality unit, (2) organisations should go the extra mile in planning, monitoring and evaluating quality, (3) departmental quality objectives and goals should involve employees in formulating the goals and objectives, eliminating misunderstanding and mistakes committed by the workforce where quality is concerned, (4) management should be committed and involved in accomplishing quality efficiency in any capacity and making sure that continuous improvement is sustained, (5) commitment by management and employee recognition will improve capability, performance and innovation. The research study accordingly has a realistic and methodological significance in terms of achieving and improving quality efficiency and sustaining continuous improvement in providing energy in South Africa

Multi-band optical micro-variability observations of BL Lacertae

We have observed BL Lacertae in the B, R and I bands for 2 nights in July, 1999, and 3 nights in July, 2001. The observations resulted in almost evenly sampled light curves, with an average sampling interval of ~5 min. The source is significantly variable in all bands. On average, the variability amplitude increases from ~5% in the I band, to ~5.5% in the R and ~6.5% in the B band light curves. The rising and decaying time scales are comparable within each band, but they increase from the B, to R and I band light curves. The optical power spectrum shows a red noise component with a slope of ~ -2. Cross-correlation analysis shows that in most cases the delay between the variations in the B and I band light curves is less than ~ 0.4 hrs. The cross-correlation functions are asymmetric, implying complex delays of the I band variations with respect to the B band variations. Furthermore, in one case we find that the I band variations are significantly delayed (by ~0.2 hrs) with respect to the B band variations. We also detect significant spectral variations: the spectrum becomes steeper as the flux increases, and the flattest spectral index corresponds to the maximum B band flux. Our results imply that the fast, intra-night variations of the source correspond to perturbations of different regions in the jet which cause localized injections of relativistic particles on time scales much sorter that the average sampling interval of the light curves. The variations are controlled by the cooling and light crossing time scales, which are probably comparable.Comment: Accepted for publication in A&

General and natural gas geology of the California quadrangle Washington County, Pennsylvania

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