Industrial Growth and the Mining Industry

A RJE symposium paper on industrial development in the then Rhodesia. Paper presented at symposium on: Industry in Rhodesia, (Paper No.4 ).No country needs much incentive to develop its natural resources to the best advantage, but the present uncertain state of the world, both economically and otherwise, lends tremendous impetus to the effort to become more and more self-supporting. The question which should be exercising the minds of those entrusted with economic development is the direction of those efforts, and the priorities which should be established to ensure a proper and integrated development of the natural and human resources at their disposal. In Rhodesia minerals in the ground constitute one of the main sources of our national wealth and their proper exploitation lies at the roots of our economic development. We misuse these resources at our peril

Travel, sexual behaviour, and the risk of contracting sexually transmitted diseases

This study investigates sexual behaviour and the risk of contracting sexually transmitted diseases among travellers departing from Hong Kong, with an aim supporting the design of local intervention in continuing health promotion. Travellers were interviewed by five trained multilingual interviewers in the departure lounge at Kai Tak International Airport, Hong Kong, between May and June 1996, by using a structured, pretested questionnaire. Forty-four percent (168/383) of the respondents who travelled at least once within the previous year had had sex with strangers during their travel and 37% (139/376) of the respondents reportedly do not use condoms during sexual intercourse. Middle-aged and married travellers were more likely to be in the high-risk group. These findings reflect the urgent need to target travellers in any strategy that is designed to prevent the spread of sexually transmitted diseases in Hong Kong and Asia Pacific region.published_or_final_versio

Screening and mortality from cervical cancer. Study shows importance of centralised organisation in screening.

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Exploring a Cognitive Basis for Learning Spatial Relationships with Augmented Reality

Augmented reality (AR) is an emergent class of interface that presents compelling possibilities for advancing spatial visualization. We offer a brief overview of AR technology and current research with in the educational realm. AR interfaces appear to provide a unique combination of visual display properties, modes of user manipulation, and interaction with spatial information. Drawing upon aspects of proprioception and sensorimotor function, we discuss how AR may have a unique and powerful link to spatial knowledge acquisition through visuo-motor involvement in the processing of information. We identify key properties of AR interfaces and how they differ from conventional visualization interfaces, followed by a discussion of theoretical perspectives that make a case for learning spatial relationships using first person manipulative AR.Recent research provides evidence that this form of AR holds cognitive advantages for learning when compared with traditional desktop 2D interfaces. We review the visual-physical connections to learning using first person manipulative AR within educational contexts. We then provide some suggestions for building future research in this area and explore its significance in the realm of spatial knowledge acquisition

Short-term effects of deep ploughing on soil C stocks following renewal of a dairy pasture in New Zealand

In New Zealand’s high producing permanent pastures the topsoil constitutes a large reservoir of soil organic carbon (SOC), which shows a marked stratification with depth. As consequence, sub-surface layers can contain 10 times less carbon than the surface soil. In permanent pastures with high carbon inputs, the formation and decomposition of these surface SOC stocks are often at equilibrium and C storage shows little change over time. Pastoral based dairy systems utilising ryegrass plus clover cultivars require renewal every 7-10 years to avoid reversion to less productive grasses. This may involve spring cultivation (either no-till, shallow till or full cultivation), summer forage cropping and autumn re-grassing. It has been hypothesised that SOC stocks can be increased by inverting the soil profile at pasture renewal through infrequent (once in 25-30 years) deep mouldboard ploughing (up to 30 cm depth). Increased C sequestration occurs when the new grass quickly rebuilds SOC stocks in the new topsoil (exposed low C sub-soil) at a rate faster than the decomposition of SOC in the rich former topsoil transferred to depth (now below 15 cm). However, benefits form accelerated C storage may be offset if crop and pasture production is adversely affected by the ploughing event (e.g., as result of compaction or excessive drainage). Hence, the aim of this work was to assess the short-term effects of infrequent inversion tillage of long-term New Zealand pastoral-based dairy soils under summer crop management and autumn re-grassing. An imperfectly drained Typic Fragiaqualf under dairy grazing was deep ploughed (approx. 25 cm) and re-sown with turnip in October 2016; other treatments included were shallow (< 10 cm) cultivation and no-till. The site was core sampled (0-40 cm) before cultivation and after 5 months of turnip growth to assess changes in SOC. Plant growth, herbage quality, and nutrient leaching were monitored during the 5-month period; root growth was assessed at the end of the crop rotation. Full cultivation transferred SOC below 10 cm depth, as expected. Soil bulk density decreased whereas root mass increased (10-20 cm depth; P < 0.05) under deep cultivation only. Besides, losses of mineral N were attenuated under deep tillage, resulting in a relative increase in crop yield. The potential for infrequent inversion tillage increasing soil C sequestration as a greenhouse gas (GHG) mitigation tool is currently being tested at other sites in New Zealand