12,143 research outputs found

    X-chromosome inactivation mosaicism in the three germ layers and the germ line of the mouse embryo

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    Electrophoretic variant forms of the X-linked enzyme phosphoglycerate kinase (PGK-1, E.C.2, 7, 2, 3) have been used to examine X-chromosome mosaicism in tissues from 121/2-day post coitum heterozygous female mouse embryos. Samples of yolk-sac endoderm, neural ectoderm, heart (mesoderm), liver (endoderm) and germ cells were analysed from each embryo. In all tissues except yolk-sac endoderm, both PGK-1 isozymes were expressed. The extent of covariance among tissues with respect to the PGK-1 isozyme contribution is consistent with all tissues being derived from the same pool of cells after X-inactivation. The covariance among tissues gives an estimate of the size of this pool (47 cells) and places the earliest time of X-inactivation in epiblast cells between 41/2 and 51/2 days post coitum. From the independent variance among tissues within an individual, the average primordial precursor pool size for the three germ layers and the germ line itself was estimated as 193 cells

    Australian Organic Market Report 2008

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    Being four years since the publication of a similar research document, the Australian Organic Market Report (AOMR) 2008 is a landmark report for the organic industry. The report will be invaluable for monitoring and planning the industry development during a period of high growth. Delivering consistent data for benchmarking growth across the various sectors of the industry, it will be a key tool for decision making by organic producers and marketers, along with interested parties such as government and media, in assisting in understanding the nature, size and development of the organic industry in Australia. Supply chain development has been hindered over many years by a lack of basic information about volumes, seasonality, continuity and quality, not only making it difficult for potentially new members of industry to feel confident about investing in organic, however also likely to cause overseas buyers to look for other countries with more comprehensive industry information. The report is an important base research document required by any growing industry. It has been commissioned by Biological Farmers of Australia (BFA), and has been carried out independently by the University of New England’s Organic Research Group. The report has the financial support of major sponsor Westpac Bank, all State Governments in Australia as well as many dedicated industry businesses

    Pattern formation in spatially heterogeneous Turing reaction-diffusion models

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    The Turing reaction–diffusion model [Phil. Trans. R. Soc. 237 (1952) 37–72] for self-organised spatial pattern formation has been the subject of a great deal of study for the case of spatially homogeneous parameters. The case of parameters which vary spatially has received less attention. Here, we show that a simple step function heterogeneity in a kinetic parameter can lead to spatial pattern formation outside the classical Turing space parameter regime for patterning. This reduces the constraints on the model parameters, extending possible applications. Furthermore, it highlights the potential importance of boundaries during pattern formation

    Australian Organic Market Report 2010

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    This is the second report the Biological Farmers of Australia has commissioned to help industry bench mark the growth and health of its sectors. This report - another significant milestone in the two decade plus history of the rapidly developing Australian certified organic sector - builds the information base for industry to benchmark production and market value against past and current claims and estimates and will enable monitoring of future growth of the certified organic market in Australia and its farming and production base. In an industry characterised by operational diversity, this report allows for performance assessment by sector. The next publication in this series is planned in 2012 (biennial since the inaugural report in 2008) as a means of providing the wider industry with invaluable and realistic market information

    Risk Pooling and the Market Crash: Lessons From Canada's Pension Plan

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    Defined contribution plans are now the nation’s primary private retirement income program and repository of retirement savings. About two thirds of the assets held in such plans are invested in equities, as is the case in the defined benefit plans they largely replaced. Equities can dramatically reduce the cost of providing retirement incomes, given their high expected returns. But, as illustrated by the recent market crash, equities are also risky. The resulting losses (and gains) in retirement income are also distributed very unevenly in the nation’s 401(k)-IRA system. The crash hardly affected the retirement prospects of the young: the bulk of the retirement income they will draw from 401(k)s and IRAs will come from future contributions and future returns. Those at the cusp of retirement, by contrast, are heavily exposed: retirement savings are then at their peak and there is little time to adjust work, saving, and retirement plans in response to the market crash. This concentration of risk is highly troubling, as the 401(k)-IRA system has become the nation’s primary private retirement income program, and has led to calls to reform. The challenge is to capture the higher expected returns equities offer in a way that provides reasonably secure and reliable incomes in retirement. One approach would make individual retirement accounts more secure and reliable through the use of mandates, defaults, guarantees, or risk-sharing arrangements. This brief offers a different approach, examining the Canada Pension Plan (CPP) and how it manages the risk that comes with investing retirement savings in equities...

    Observing a Light CP-Violating Higgs Boson in Diffraction

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    Light CP-violating Higgs bosons with mass lower than 70 GeV might have escaped detection in direct searches at the LEP collider. They may remain undetected in conventional search channels at the Tevatron and LHC. In this Letter we show that exclusive diffractive reactions may be able to probe for the existence of these otherwise elusive Higgs particles. As a prototype example, we calculate diffractive production cross-sections of the lightest Higgs boson within the framework of the Minimal Supersymmetric Standard Model with explicit CP violation. Our analysis shows that the challenging regions of parameter space corresponding to a light CP-violating Higgs boson might be accessible at the LHC provided suitable proton tagging detectors are installed.Comment: 9 pages, LaTeX, 2 figures, version as to appear in Phys. Rev.

    HepData and JetWeb: HEP data archiving and model validation

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    The CEDAR collaboration is extending and combining the JetWeb and HepData systems to provide a single service for tuning and validating models of high-energy physics processes. The centrepiece of this activity is the fitting by JetWeb of observables computed from Monte Carlo event generator events against their experimentally determined distributions, as stored in HepData. Caching the results of the JetWeb simulation and comparison stages provides a single cumulative database of event generator tunings, fitted against a wide range of experimental quantities. An important feature of this integration is a family of XML data formats, called HepML.Comment: 4 pages, 0 figures. To be published in proceedings of CHEP0

    Chasing the Chatbots: Directions for Interaction and Design Research

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    Big tech-players have been successful in pushing the chatbots forward. Investments in the technology are growing fast, as well as the number of users and applications available. Instead of driving investments towards a successful diffusion of the technology, user-centred studies are currently chasing the popularity of chatbots. A literature analysis evidences how recent this research topic is, and the predominance of technical challenges rather than understanding users’ perceptions, expectations and contexts of use. Looking for answers to interaction and design questions raised in 2007, when the presence of clever computers in everyday life had been predicted for the year 2020, this paper presents a panorama of the recent literature, revealing gaps and pointing directions for further user-centred research
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