The F-signature and strong F-regularity

We show that the F-signature of a local ring of characteristic p, defined by Huneke and Leuschke, is positive if and only if the ring is strongly F-regular.Comment: revised version, incorporating referee's comments. 6 page

Electricity network scenarios for 2020

This report presents a set of scenarios for the development of the electricity supply industry in Great Britain in the years to 2020. These scenarios illustrate the varied sets of background circumstances which may influence the industry over the coming years – including political and regulatory factors, the strength of the economy and the level to which environmentally-driven restrictions and opportunities influence policy and investment decisions. Previous work by the authors (Elders et al, 2006) has resulted in a set of six scenarios illustrating possible developments in the electricity industry in the period up to 2050. While such scenarios are valuable in gauging the long-term direction of the electricity industry and its economic and environmental consequences, shorter-range scenarios are useful in assessing the steps necessary to achieve these long-range destinations, and to determine their relationship to current trends, policies and targets. In this chapter, a set of medium-range scenarios focused on the year 2020 is developed and described. These scenarios are designed to be consistent both with the current state of the electricity supply industry in Great Britain, and with the achievement of the ultimate electricity generation, supply and utilisation infrastructure and patterns described in each of the 2050 scenarios. The consequences of these scenarios in terms of the emissions of carbon dioxide are evaluated and compared with other predictions. The SuperGen 2020 scenarios described in this report were developed as a collaborative effort between the SuperGen project team and the ITI-Energy Networks Project team both based at the University of Strathclyde

Application of Additive Manufacturing to the Digital Restoration of Archaeological Artifacts

AbstractThis paper reports a substantial body of work that has been done in this area, which has been used to determine how Additive Manufacturing (AM) and subsequent processes should be optimally applied, and introduces a series of process maps that have been generated to guide future practical work with a combination of questionnaires and expert interviews for validating the process maps. The outputs from the research should prove to be valuable to anyone working in this field. The main contribution to knowledge is the characterisation of archaeological artefacts and the resultant process maps derived from this characterization

On the extent of genetic variation for transpiration efficiency in sorghum

A glasshouse study examined 49 diverse sorghum lines for variation in transpiration efficiency. Three of the 49 lines grown were Sorghum spp. native to Australia; one was the major weed Johnson grass (Sorghum halepense), and the remaining 45 lines were cultivars of Sorghum bicolor. All plants were grown under non-limiting water and nutrient conditions using a semi-automatic pot watering system designed to facilitate accurate measurement of water use. Plants were harvested 56–58 days after sowing and dry weights of plant parts were determined. Transpiration efficiency differed signficantly among cultivars. The 3 Australian native sorghums had much lower transpiration efficiency than the other 46 cultivars, which ranged from 7·7 to 6·0 g/kg. For the 46 diverse cultivars, the ratio of range in transpiration efficiency to its l.s.d. was 2·0, which was similar to that found among more adapted cultivars in a previous study. This is a significant finding as it suggests that there is likely to be little pay-off from pursuing screening of unadapted material for increased variation in transpiration efficiency. It is necessary, however, also to examine absolute levels of transpiration efficiency to determine whether increased levels have been found. The cultivar with greatest transpiration efficiency in this study (IS9710) had a value 9% greater (P < 0·05) than the accepted standard for adapted sorghum cultivars. The potential impact of such an increase in transpiration efficiency warrants continued effort to capture it. Transpiration efficiency has been related theoretically and experimentally to the degree of carbon isotope discrimination in leaf tissue in sorghum, which thus offers a relatively simple selection index. In this study, the variation in transpiration efficiency was not related simply to carbon isotope discrimination. Significant associations of transpiration efficiency with ash content and indices of photosynthetic capacity were found. However, the associations were not strong. These results suggest that a simple screening technique could not be based on any of the measures or indices analysed in this study. A better understanding of the physiological basis of the observed genetic differences in transpiration efficiency may assist in developing reliable selection indices. It was concluded that the potential value of the improvement in transpiration efficiency over the accepted standard and the degree of genetic variation found warrant further study on this subject. It was suggested that screening for genetic variation under water-limiting conditions may provide useful insights and should be pursued

An Arabidopsis mutant disrupted in valine catabolism is also compromised in peroxisomal fatty acid β-oxidation

AbstractCharacterisation of the Arabidopsis dbr5 mutant, which was isolated on the basis of 2,4-dichlorophenoxybutyric acid (2,4-DB) resistance, revealed that it is disrupted in the CHY1 gene. CHY1 encodes a peroxisomal protein that is 43% identical to the mammalian β-hydroxyisobutryl-CoA hydrolase of valine catabolism. We show that 2,4-DB resistance and the associated sucrose dependent seedling growth are due to a large activity decrease of 3-ketoacyl-CoA thiolase, which is involved in peroxisomal fatty acid β-oxidation. 14C-feeding studies demonstrate that dbr5 and chy1 seedlings are reduced in valine catabolism. These data support the hypothesis that CHY1 plays a key role in peroxisomal valine catabolism and that disruption of this enzyme results in accumulation of a toxic intermediate, methacrylyl-CoA, that inhibits 3-ketoacyl-CoA thiolase activity and thus blocks peroxisomal β-oxidation. We also show that CHY1 is repressed in seedlings grown on sugars, which suggests that branched chain amino acid catabolism is transcriptionally regulated by nutritional status

Book Reviews

The following publications have been reviewed by the authors;Design and Technology in Process: Survival - reviewed by Ian McLintockStained Glass Made Easy - reviewed by Mel MarsIT in Emergencies Pack - reviewed by Dominic ClareA Taste of Quality Pack McDonalds - reviewed by Jonty CrockatHands on CAD - reviewed by Phillip BrownriggSchool Science and Technology: Some Issues and Perspectives - reviewed by  J. ComptonManaging Health and Safety in School Workshops - reviewed by  Faith Graha

Combining GAL4 GFP enhancer trap with split luciferase to measure spatiotemporal promoter activity in Arabidopsis.

In multicellular organisms different types of tissues have distinct gene expression profiles associated with specific function or structure of the cell. Quantification of gene expression in whole organs or whole organisms can give misleading information about levels or dynamics of expression in specific cell types. Tissue- or cell-specific analysis of gene expression has potential to enhance our understanding of gene regulation and interactions of cell signalling networks. The Arabidopsis circadian oscillator is a gene network which orchestrates rhythmic expression across the day/night cycle. There is heterogeneity between cell and tissue types of the composition and behaviour of the oscillator. In order to better understand the spatial and temporal patterns of gene expression, flexible tools are required. By combining a Gateway®-compatible split luciferase construct with a GAL4 GFP enhancer trap system, we describe a tissue-specific split luciferase assay for non-invasive detection of spatiotemporal gene expression in Arabidopsis. We demonstrate the utility of this enhancer trap-compatible split luciferase assay (ETSLA) system to investigate tissue-specific dynamics of circadian gene expression. We confirm spatial heterogeneity of circadian gene expression in Arabidopsis leaves and describe the resources available to investigate any gene of interest