54,912 research outputs found

    P-parity of charmed particles from associative photoproduction of D and D^*-mesons

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    We suggest to measure the triple polarization correlations in the exclusive associative charm particle photoproduction, vector gamma + vector p --> vector Lambda_c^{++} bar{D^0} with linearly polarized photons, as a method to determine the P-parity of the charmed D-meson. The dependence of these correlations on the parity P(N Lambda_c D) can be predicted in model independent way. The t-dependence of the differential cross section for vector meson photoproduction, gamma + p --> Lambda_c^{++} bar{D^{*0}}, in a model based on D-exchange, is also sensitive to P(N Lambda_c D).Comment: 11 pages, 1 figur

    Diverse, remote and innovative - Prospects for a globally unique electricity network and market in Western Australia

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    WA’s electricity industry supply infrastructure comprises the South West Inter-connected System (SWIS), the North West Interconnected System (NWIS) and 29 regional noninterconnected power systems 1. WA exhibits a diversity of generation systems located in some of the most isolated regions of Australia, supplying a wide range of energy demand profiles. These characteristics and the unique networks that comprises WA’s electricity infrastructure makes WA a unique place to research, develop and integrate new technical options within a world-class industrialised electricity system

    Australian carbon biosequestration and bioenergy policy co-evolution: mechanisms, mitigation and convergence

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    The intricacies of international land-use change and forestry policy reflect the temporal, technical and political difficulty of integrating biological systems and climate change mitigation. The plethora of co-existing policies with varied technical rules, accreditation requirements, accounting methods, market registries, etc., disguise the unequal efficacies of each mechanism. This work explores the co-evolution and convergence of Australian voluntary and mandatory climate-related policies at the biosequestration-bioenergy interface. Currently, there are temporal differences between the fast-evolving and precise climate-change mechanisms, and the long-term 'permanence' sought from land use changes encouraged by biosequestration instruments. Policy convergence that favours the most efficient, appropriate and scientifically substantiated policy mechanisms is required. These policies must recognise the fundamental biological foundation of biosequestration, bioenergy, biomaterial industrial development and other areas such as food security and environmental concerns. Policy mechanisms that provide administrative simplicity, project longevity and market certainty are necessary for rural and regional Australians to cost-effectively harness the considerable climate change mitigation potential of biological systems

    Diverse, remote and innovative - Prospects for a globally unique electricity network and market in Western Australia

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    WA’s electricity industry supply infrastructure comprises the South West Inter-connected System (SWIS), the North West Interconnected System (NWIS) and 29 regional non-interconnected power systems 1. WA exhibits a diversity of generation systems located in some of the most isolated regions of Australia, supplying a wide range of energy demand profiles. These characteristics and the unique networks that comprises WA’s electricity infrastructure makes WA a unique place to research, develop and integrate new technical options within a world-class industrialised electricity system

    Small-scale (≤6 kWe) stand-alone and grid-connected photovoltaic, wind, hydroelectric, biodiesel, and wood gasification system's simulated technical, economic, and mitigation analyses for rural regions in Western Australia

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    This research develops models and simulations of technical performance, net emission reductions, and discounted market values of thirteen small-scale (≤6 kWe) renewable energy projects. The research uses a simple methodology suitable for small private entities and governments to compare alternative investment options for both climate change mitigation and adaptation in the southwest of Western Australia. The system simulation and modelling results indicate that privately-owned, small-scale, grid-connected renewable energy systems were not competitive options for private entities relative to sourcing electricity from electricity networks, despite subsidies. The total discounted capital and operating costs, combined with the minimal mitigation potentials of the small-scale renewable energy systems resulted in unnecessarily high electricity costs and equivalent carbon prices, relative to grid-connection and large-scale clean energy systems. In contrast, this research suggests that small-scale renewable energy systems are cost-effective for both private entities and governments and exhibit good mitigation potentials when installed in remote locations far from the electricity network, mostly displacing diesel capacity

    A technical, economic, and greenhouse gas emission analysis of a homestead-scale grid-connected and stand-alone photovoltaic and diesel systems, against electricity network extension

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    This research compares two generation components in grid-connected and stand-alone power supply (SPS) systems (6 kWp solar photovoltaic array, and a 6 kWp diesel generator), separately supplying a homestead's electricity load (12 kWh day-1 average, 10 kWp), against a 2 km underground electricity distribution line extension. The technical simulation intervals (15 min) included realistic peak demand and generation component outputs, based on actual load data collected from an existing homestead and local meteorological data in the southwest of Western Australia. The separate emission and economic calculations incorporated technical simulation data, were based on emission factors for the region, used 2010 market prices for capital and operational costs, all projected over 15 years. The economic model included an 8% real discount rate, and several assumptions customised for each scenario. The results suggest small-scale distributed electricity generation systems are currently unattractive economically when compared to medium distance network extension, and increased the cost of electricity for private individuals (or governments if subsidised) with small mitigation benefits. The scenario results and discussions illuminate the specific economic barriers for small-scale photovoltaic components in both stand-alone and grid-connected systems in areas proximal to electricity distribution networks in regional Western Australia

    A eubacterial origin for the human tRNA nucleotidyltransferase?

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    tRNA CCA-termini are generated and maintained by tRNA nucleotidyltransferases. Together with poly(A) polymerases and other enzymes they belong to the nucleotidyltransferase superfamily. However, sequence alignments within this family do not allow to distinguish between CCA-adding enzymes and poly(A) polymerases. Furthermore, due to the lack of sequence information about animal CCA-adding enzymes, identification of corresponding animal genes was not possible so far. Therefore, we looked for the human homolog using the baker's yeast tRNA nucleotidyltransferase as a query sequence in a BLAST search. This revealed that the human gene transcript CGI-47, (\#AF151805) deposited in GenBank is likely to encode such an enzyme. To identify the nature of this protein, the cDNA of the transcript was cloned and the recombinant protein biochemically characterized, indicating that CGI-47 encodes a bona fide CCA-adding enzyme and not a poly(A) polymerase. This confirmed animal CCA-adding enzyme allowed us to identify putative homologs from other animals. Calculation of a neighbor-joining tree, using an alignment of several CCA-adding enzymes, revealed that the animal enzymes resemble more eubacterial ones than eukaryotic plant and fungal tRNA nucleotidyltransferases, suggesting that the animal nuclear cca genes might have been derived from the endosymbiotic progenitor of mitochondria and are therefore of eubacterial origin

    Automated protein structure calculation from NMR data

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    Current software is almost at the stage to permit completely automatic structure determination of small proteins of < 15 kDa, from NMR spectra to structure validation with minimal user interaction. This goal is welcome, as it makes structure calculation more objective and therefore more easily validated, without any loss in the quality of the structures generated. Moreover, it releases expert spectroscopists to carry out research that cannot be automated. It should not take much further effort to extend automation to ca 20 kDa. However, there are technological barriers to further automation, of which the biggest are identified as: routines for peak picking; adoption and sharing of a common framework for structure calculation, including the assembly of an automated and trusted package for structure validation; and sample preparation, particularly for larger proteins. These barriers should be the main target for development of methodology for protein structure determination, particularly by structural genomics consortia

    The effect of systematic misperception of income on the subjective poverty line

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    Income Distribution;macroeconomics
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