Disposal in 4- to 5-km-deep boreholes offers a safe, secure, environmentally sound, and potentially economic solution for high-level radioactive wastes, including spent fuel and fissile materials. ...Three versions of such disposals are under investigation: two variants of low-temperature disposal for low-heat-generating wastes and a high-temperature one for wastes generating sufficient heat to partly melt the host rock. A numerical model for the conductive transfer of heat is used to calculate the spatial and temporal distribution of temperature in and around these disposals. Sample solutions are given for two cases of each of the disposal versions, and the outcomes are discussed in the context of their significance for the safety and viability of the disposal. It is concluded that one or other of the three versions of deep borehole disposal could accommodate almost any type of high-level waste.
Precise refinement of synaptic connectivity is the result of activity-dependent mechanisms in which coincidence-dependent calcium signaling by NMDA receptors (NMDARs) under control of the ...voltage-dependent Mg2+ block might play a special role. In the developing rodent trigeminal system, the pattern of synaptic connections between whisker-specific inputs and their target cells in the brainstem is refined to form functionally and morphologically distinct units (barrelettes). To test the role of NMDA receptor signaling in this process, we introduced the N598R mutation into the native NR1 gene. This leads to the expression of functional NMDARs that are Mg2+ insensitive and Ca2+ impermeable. Newborn mice expressing exclusively NR1 N598R-containing NMDARs do not show any whisker-related patterning in the brainstem, whereas the topographic projection of trigeminal afferents and gross brain morphology appear normal. Furthermore, the NR1 N598R mutation does not affect expression levels of NMDAR subunits and other important neurotransmitter receptors. Our results show that coincidence detection by, and/or Ca2+ permeability of, NMDARs is necessary for the development of somatotopic maps in the brainstem and suggest that highly specific signaling underlies synaptic refinement.
The Shiant Isles Main Sill of the British Tertiary Igneous Province is a classic example of a sifferentiated, alkaline basic sill. Four separate intrusions, each emplaced internally in rapid ...succession, form a 165-m-thick sill hosted by Lower Jurassic sedimentary rocks.
The objective of this paper is to demonstrate how the experience and knowledge of construction workers can be utilised to encourage healthy ageing and facilitate healthy working behaviours. The ...population is ageing globally leading to an increasingly ageing workforce and with the abolishment of an official retirement age working into later life is becoming commonplace. Natural age-related declines such as reduced vision, hearing and muscle strength make it difficult to remain in industries such as construction where heavy manual labour is commonplace. A previous study by the authors found that construction workers have good ideas for both maintaining and improving their health and well-being at work. Workers suggested solutions which could facilitate healthy ageing such as improving facilities and personal protective equipment and wanting better knowledge transfer systems such as more apprentices to pass their knowledge on to. This paper discusses how these findings could be used in the construction industry to improve health, well-being and healthy ageing. Focus groups with industry stakeholders presented them with these ideas; they were asked about their perceptions of older workers and how they thought the ideas suggested by their workforce could be used to improve health, well-being and ageing. Barriers and opportunities to change were investigated and stakeholders were encouraged to consider how they could encourage involvement of their workers using participatory ergonomics techniques. Stakeholders were positive about the older workforce and were keen to promote change within their companies. This research forms part of a larger study, sponsored by Age UK's Research into Ageing Fund, which aims to produce a resource for dissemination across the industry, encouraging engagement of the workforce to facilitate healthy working behaviours. It is essential that ideas from workers are harnessed and utilised to ensure that all workers can age healthily at work.
Successful deployment of the facilities management (FM) function for any major development will depend upon the ability to identify, communicate, and manage opportunities to help support an ...organization's business objectives at the earliest possible time. This implies a more holistic view for the FM function as reflected by strategic facilities management, and also the ability to address its requirements at an early enough stage of the development process. The paper presents a case from a major hospital development where considerations of such an early role for FM was applied at the design stage and discusses some of the impacts of this approach. Essentially, a shift in the consideration of major developments as construction projects to FM services provision. This orientation makes the development of the scheme one of designing for FM.
Despite recent changes in legislation and advances towards an integrated project-wide approach, health and safety management in the construction industry is still a major problem, involving a ...substantial cost to business, society and individuals. A prerequisite to improving the situation and developing an effective management strategy is monitoring, providing a detailed understanding of the effectiveness of different approaches to intervention. This paper describes a feasibility study using in-depth interviews with senior managers to explore the quality of accident and health data of nine large, high profile companies from the engineering construction sector. The interview dialogue comprised a series of questions and issues to be explored on the organization's accident reporting systems (e.g. what is reported, analysis performed, computerization), unsafe act and near miss auditing (e.g. definition, validity), failure type indicators (e.g. auditing, quantification) and safety culture indicators (e.g. commitment, health). Although safety was a priority for companies, health (i.e. medicals and monitoring systems) had not been given the same consideration, especially with regard to subcontracted labour. This study shows that the validity of accident statistics as a measure of safety remains a limitation, and that there is a requirement for a consistent and integrated approach to the measurement of health and safety performance.
Standardization and pre-assembly (S&P) are not new, but their application and their drivers, pragmatism and perception, need to be considered in the light of current technology and management ...practice. There are lessons to be learned from a historical review, but there are also numerous myths that must be dispelled: houses are not cars; maximum standardization is not always the answer; and, S&P do not have to cost more. Steven Groák worked with the author on the research project 'Adding value to construction projects through standardisation and pre-assembly' funded by CIRIA (Construction Industry Research and Information Association). The CIRIA project, which forms the basis of this paper, aimed to produce a review of the subject and guidance for clients and project teams through a comprehensive literature review, expert work5 shops and case study research. The paper defines S&P, discusses past, present and future applications (providing case study evidence) and presents the key benefits and implications of the optimized use of standardization and pre-assembly.
Summary Background Co-trimoxazole prophylaxis can reduce mortality from untreated HIV infection in Africa; whether benefits occur alongside combination antiretroviral therapy (ART) is unclear. We ...estimated the effect of prophylaxis after ART initiation in adults. Methods Participants in our observational analysis were from the DART randomised trial of management strategies in HIV-infected, symptomatic, previously untreated African adults starting triple-drug ART with CD4 counts lower than 200 cells per μL. Co-trimoxazole prophylaxis was not routinely used or randomly allocated, but was variably prescribed by clinicians. We estimated effects on clinical outcomes, CD4 cell count, and body-mass index (BMI) using marginal structural models to adjust for time-dependent confounding by indication. DART was registered, number ISRCTN13968779. Findings 3179 participants contributed 14 214 years of follow-up (8128 57% person-years on co-trimoxazole). Time-dependent predictors of co-trimoxazole use were current CD4 cell count, haemoglobin concentration, BMI, and previous WHO stage 3 or 4 events on ART. Present prophylaxis significantly reduced mortality (odds ratio 0·65, 95% CI 0·50–0·85; p=0·001). Mortality risk reduction on ART was substantial to 12 weeks (0·41, 0·27–0·65), sustained from 12–72 weeks (0·56, 0·37–0·86), but not evident subsequently (0·96, 0·63–1·45; heterogeneity p=0·02). Variation in mortality reduction was not accounted for by time on co-trimoxazole or current CD4 cell count. Prophylaxis reduced frequency of malaria (0·74, 0·63–0·88; p=0·0005), an effect that was maintained with time, but we observed no effect on new WHO stage 4 events (0·86, 0·69–1·07; p=0·17), CD4 cell count (difference vs non-users, −3 cells per μL −12 to 6; p=0·50), or BMI (difference vs non-users, −0·04 kg/m2 −0·20 to 0·13); p=0·68. Interpretation Our results reinforce WHO guidelines and provide strong motivation for provision of co-trimoxazole prophylaxis for at least 72 weeks for all adults starting combination ART in Africa. Funding UK Medical Research Council, the UK Department for International Development, the Rockefeller Foundation, GlaxoSmithKline, Gilead Sciences, Boehringer-Ingelheim, and Abbott Laboratories.
The manual handling of concrete highway kerbs remains commonplace in the construction industry despite obvious risks to operatives. This study was undertaken to find out why kerb installation still ...includes manual handling, to identify the alternatives that exist and to consider how the organisation of the work affects exposure to risk. Focus groups were held with industry professionals to discuss kerb design, installation and the training of operatives, with site visits and interviews undertaken to place the focus group findings in context. The focus group discussions highlighted manufacturer's ‘myopia’, a lack of installation knowledge of designers and shortfalls in training for installation work. It was concluded that risks to the health of construction workers remain as they are not considered in the design of the product, design of the work or ameliorated by adequate risk assessment. Recommendations from the research are that a pro-active approach to health needs to be adopted by the manufacturers of heavy construction products. Designers of work requiring the use of heavy products need to have more experience of site operations, and education and training in manual handling is desirable at all levels in construction organisations.
Purpose - Offsite is one of the main innovative techniques employed in the contemporary UK construction sector. Building maintenance accounts for over 5 percent of the UK's gross domestic product of ...which bathrooms are regarded as a critical area, with potential high risks and defects. However, the importance of its maintenance has been largely underestimated and research into this area appears to be limited. This paper aims to address this knowledge gap by investigating the maintenance performance of offsite and in situ bathrooms for student accommodation.Design methodology approach - The paper examines 732 maintenance records over three years of 216 precast concrete modules, 84 Glass Reinforced Polyester (GRP) modules and 96 traditionally-built in situ bathrooms.Findings - The research found that offsite modules outperformed in situ bathrooms in terms of maintenance. GRP modules created the least maintenance problems, compared to precast modules and in situ bathrooms. The maintenance of in situ bathrooms was more complex than offsite modules, and involved more diverse problematic areas. The main causes of the problems included inappropriate design; poor build workmanship, lack of quality of component materials and improper usage by occupants. This supports a parallel study that found that the costs associated with maintenance were significantly higher for in situ bathrooms than for the equivalent offsite solutions.Research limitations implications - The paper contributes to understanding the problems of offsite bathroom modules requiring maintenance in comparison with in situ bathrooms and their possible causes. Key aspects of offsite bathrooms including drainage, toilets, vents and sinks should be improved. Quality of component materials used for in situ bathrooms should be ensured. These improvements can only be achieved through better design for maintenance with clients' aspiration embodied. The findings should assist in design decision making of selecting bathrooms for residential buildings. However, a balanced approach, taking into account other factors for such selection, is open for future investigation.Originality value - The framework of strategies developed should improve the innovative design of bathrooms manufactured offsite and help maintain them for better lifecycle performance.
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