Mining wheat germplasm collections for yield enhancing traits

The material in genebanks includes valuable traditional varieties and landraces, non-domesticated species, advanced and obsolete cultivars, breeding lines and genetic stock. It is the wide variety of potentially useful genetic diversity that makes collections valuable. While most of the yield increases to date have resulted from manipulation of a few major traits (such as height, photoperiodism, and vernalization), meeting future demand for increased yields will require exploitation of novel genetic resources. Many traits have been reported to have potential to enhance yield, and high expression of these can be found in germplasm collections. To boost yield in irrigated situations, spike fertility must be improved simultaneously with photosynthetic capacity. CIMMYT's Wheat Genetic Resources program has identified a source of multi-ovary florets, with up to 6 kernels per floret. Lines from landrace collections have been identified that have very high chlorophyll concentration, which may increase leaf photosynthetic rate. High chlorophyll concentration and high stomatal conductance are associated with heat tolerance. Recent studies, through augmented use of seed multiplication nurseries, identified high expression of these traits in bank accessions, and both traits were heritable. Searches are underway for drought tolerance traits related to remobilization of stem fructans, awn photosynthesis, osmotic adjustment, and pubescence. Genetic diversity from wild relatives through the production of synthetic wheats has produced novel genetic diversity.

The City as Territory: Aerial Photography and the Everyday

For most of us, the modern city is somewhat unintelligible, both in terms of its structure and its significance. As an urbanised population, the city should be our natural territory, but the pace and scope of its change leads to an illegibility of its form and character. There is infinite, seemingly significant, activity - demolition, building and makeover - but there is little sense of the city as a site of meaning.

The design of hazard risk assessment matrices for ranking occupational health risks and their application in mining and minerals processing

Two hazard risk assessment matrices for the ranking of occupational health risks are described. The qualitative matrix uses qualitative measures of probability and consequence to determine risk assessment codes for hazard-disease combinations. A walk-through survey of an underground metalliferous mine and concentrator is used to demonstrate how the qualitative matrix can be applied to determine priorities for the control of occupational health hazards. The semi-quantitative matrix uses attributable risk as a quantitative measure of probability and uses qualitative measures of consequence. A practical application of this matrix is the determination of occupational health priorities using existing epidemiological studies. Calculated attributable risks from epidemiological studies of hazard-disease combinations in mining and minerals processing are used as examples. These historic response data do not reflect the risks associated with current exposures. A method using current exposure data, known exposure-response relationships and the semi-quantitative matrix is proposed for more accurate and current risk rankings.

City profile - Colombo

Rooted in a history that dates back 1500 years, the concentration of economic activity and infrastructure in Colombo represents an extreme case of urban primacy within the national context of Sri Lanka. Located on the West Coast of the country, the Colombo metropolitan area accommodates a quarter of the country's 18.6 million population, and is the economic and political core of the country. However, Colombo is a city of extremes. Its modem and well-serviced core stands in stark contrast to the circumstances of more than half of its population, who live in poorly serviced shack and shanty settlements. The proportion of the population living in these areas continues to expand, notwithstanding a history of innovative and participatory approaches to development planning and management. Complicating these development challenges, the potential of the city is undermined by a civil war that has been under way since the early 1980s, taking an immense toll in loss of life, political polarization, and economic opportunity costs. This paper traces Colombo's historical development, provides a description of contemporary characteristics and challenges faced by the city, and examines the evolution of plans and programmes designed to improve the conditions of low-income settlements in the city. (C) 2002 Elsevier Science Ltd. All rights reserved.

New arsenite-oxidizing bacteria isolated from Australian gold mining environments - Phylogenetic relationships

Nine novel arsenite-oxidizing bacteria have been isolated from two different gold mine environments in Australia. Four of these organisms grow chemolithoautotrophically with oxygen as the terminal electron acceptor, arsenite as the electron donor, and carbon dioxide-bicarbonate as the sole carbon source. Five heterotrophic arsenite-oxidizing bacteria were also isolated, one of which was found to be both phylogenetically and physiologically identical to the previously described heterotrophic arsenite oxidizer misidentified as Alcaligenes faecalis. The results showed that this strain belongs to the genus Achromobacter. Phylogenetically, the arsenite-oxidizing bacteria fall within two separate subdivisions of the Proteobacteria. Interestingly, the chemolithoautotrophic arsenite oxidizers belong to the alpha-Proteobacteria, whereas the heterotrophic arsenite oxidizers belong to the beta-Proteobacteria.

Communities of the postindustrial city

The authors discern the community structure of the postindustrial city, with reference to Australia. They focus empirically on three major types of Australian urban center: urban regions. metropolitan areas that are not part of urban regions, and other major cities. These three account for almost three-quarters of the Australian population. The authors draw on a conceptualization formulated by Marcuse and van Kempen to guide the analysis, with a combination of cluster analysis and discriminant analysis being applied to aggregate (essentially census) data to identify the communities. Nine major Australian urban communities are identified-four are affluent. four are disadvantaged. and one is a working-class community. The communities found, however, differed greatly from those cited in the Marcuse and van Kempen schema.