1,833 research outputs found

    Review: Janna Thompson: Intergenerational Justice

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    Book Review Janna Thompson (2009): Intergenerational Justice. Rights and Responsibilities in an Intergenerational Polity. New York: Routledge. 191 pages. ISBN: 0415996287. Price £80.75

    Review: Ed Howker and Shiv Malik: The Jilted Generation

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    Book Review Ed Howker and Shiv Malik (2010): Jilted Generation. How Britain Has Bankrupted its Youth. London: Icon Books Ltd. 256 pages. ISBN: 1848311982. Price £8.99

    An experimental investigation of budget rejection authority placement in three-tier hierarchies

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    In a participative budgeting setting, this paper examines the relative merits of different choices regarding to whom to assign budget rejection authority in a hierarchical firm. While the participative budgeting literature has traditionally examined dyadic firms (i.e. firms consisting of only an owner and a worker), many firms exist as taller hierarchies. In such firms, the question of where to locate an important budgetary control – rejection authority – in order to promote improved budgetary reporting becomes meaningful. It is hypothesized that delegating budget rejection authority to the manager leads to increased slack consumption by the agent in comparison to the situation in which the principal retains such authority. Research questions address whether the agents report more accurately when both the manager and the principal have rejection authority by comparison to the arrangement in which only one of these individuals hold such power. Results generally suggest that delegating rejection authority to the manager does not entail agency related costs. Further, agent slack capture is least when the control is duplicated but this benefit comes at a substantial decrease in the amount of surplus the firm can capture

    Moored acoustic travel time (ATT) current meters : evolution, performance, and future designs

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    New laboratory measurements and numeric model studies show the present folded-path ATT current meters are stable and sensitive, but are not well suited for mean flow observations in surface gravity waves. Alternate designs which reduce unwanted wake effects are proposed. ATT flowmeter history, principles of acoustic flow sensors, mean flow near cylinders, and the need for linear flow sensors are reviewed.Prepared for the Office of Naval Research under Contract Number N00014-76-C-0197; NR083-400 to the Woods Hole Oceanographic Institution

    A quantitative screen for metabolic enzyme structures reveals patterns of assembly across the yeast metabolic network.

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    Despite the proliferation of proteins that can form filaments or phase-separated condensates, it remains unclear how this behavior is distributed over biological networks. We have found that 60 of the 440 yeast metabolic enzymes robustly form structures, including 10 that assemble within mitochondria. Additionally, the ability to assemble is enriched at branch points on several metabolic pathways. The assembly of enzymes at the first branch point in de novo purine biosynthesis is coordinated, hierarchical, and based on their position within the pathway, while the enzymes at the second branch point are recruited to RNA stress granules. Consistent with distinct classes of structures being deployed at different control points in a pathway, we find that the first enzyme in the pathway, PRPP synthetase, forms evolutionarily conserved filaments that are sequestered in the nucleus in higher eukaryotes. These findings provide a roadmap for identifying additional conserved features of metabolic regulation by condensates/filaments

    Observations Supporting the Role of Magnetoconvection in Energy Supply to the Quiescent Solar Atmosphere

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    Identifying the two physical mechanisms behind the production and sustenance of the quiescent solar corona and solar wind poses two of the outstanding problems in solar physics today. We present analysis of spectroscopic observations from the Solar and Heliospheric Observatory that are consistent with a single physical mechanism being responsible for a significant portion of the heat supplied to the lower solar corona and the initial acceleration of the solar wind; the ubiquitous action of magnetoconvection-driven reprocessing and exchange reconnection of the Sun's magnetic field on the supergranular scale. We deduce that while the net magnetic flux on the scale of a supergranule controls the injection rate of mass and energy into the transition region plasma it is the global magnetic topology of the plasma that dictates whether the released ejecta provides thermal input to the quiet solar corona or becomes a tributary that feeds the solar wind.Comment: 34 pages, 13 figures - In press Astrophysical Journal (Jan 1 2007

    IPv6 and IPsec Tests of a Space-Based Asset, the Cisco Router in Low Earth Orbit (CLEO)

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    This report documents the design of network infrastructure to support testing and demonstrating network-centric operations and command and control of space-based assets, using IPv6 and IPsec. These tests were performed using the Cisco router in Low Earth Orbit (CLEO), an experimental payload onboard the United Kingdom--Disaster Monitoring Constellation (UK-DMC) satellite built and operated by Surrey Satellite Technology Ltd (SSTL). On Thursday, 29 March 2007, NASA Glenn Research Center, Cisco Systems and SSTL performed the first configuration and demonstration of IPsec and IPv6 onboard a satellite in low Earth orbit. IPv6 is the next generation of the Internet Protocol (IP), designed to improve on the popular IPv4 that built the Internet, while IPsec is the protocol used to secure communication across IP networks. This demonstration was made possible in part by NASA s Earth Science Technology Office (ESTO) and shows that new commercial technologies such as mobile networking, IPv6 and IPsec can be used for commercial, military and government space applications. This has direct application to NASA s Vision for Space Exploration. The success of CLEO has paved the way for new spacebased Internet technologies, such as the planned Internet Routing In Space (IRIS) payload at geostationary orbit, which will be a U.S. Department of Defense Joint Capability Technology Demonstration. This is a sanitized report for public distribution. All real addressing has been changed to psueco addressing

    Arabidopsis transcript profiling on Affymetrix GeneChip arrays

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    DNA microarrays are becoming a frequently used research tool. Whilst several studies have confirmed the reproducibility of analysing the same RNA samples on duplicate arrays, there is little analysis of the reproducibility of the results of transcript profiling between microarrays carrying different probes to a common set of genes. To address this question, we compared the performance and reproducibility of two microarrays commonly used in plant research, the Affymetrix Arabidopsis AG array containing more than 8000 probe sets and the Affymetrix Arabidopsis ATH1 array containing more than 22 000 redesigned probe sets. A total of 21 different RNA samples were labelled and hybridized in parallel to the two microarray types. Focusing on the overlap of more than 7300 targets detected with both arrays, we found a high degree of reproducibility. Despite the use of different probe sets, both signal and signal log ratio were very similar for most genes. However, genes that were called absent or not changed by Affymetrix' statistical algorithm implemented in MAS5.0 showed considerably less conservation of expression patterns. Moreover, we identified about 300 genes that yielded strongly different measurements with the two microarrays, emphasizing that RNA profiling data need careful interpretation. Overall, this study shows that results obtained with ATH1 and AG arrays are very comparable and hence that the analysis is largely independent of probe sets. However, the result emphasize the need for appropriate filtering schemes such as those based on the present and change calls provided by MAS5.0 rather than reliance solely on signal value

    Re-expression of IGF-II is important for beta cell regeneration in adult mice

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    Background The key factors which support re-expansion of beta cell numbers after injury are largely unknown. Insulin-like growth factor II (IGF-II) plays a critical role in supporting cell division and differentiation during ontogeny but its role in the adult is not known. In this study we investigated the effect of IGF-II on beta cell regeneration. Methodology/Principal Findings We employed an in vivo model of ‘switchable’ c-Myc-induced beta cell ablation, pIns-c-MycERTAM, in which 90% of beta cells are lost following 11 days of c-Myc (Myc) activation in vivo. Importantly, such ablation is normally followed by beta cell regeneration once Myc is deactivated, enabling functional studies of beta cell regeneration in vivo. IGF-II was shown to be re-expressed in the adult pancreas of pIns-c-MycERTAM/IGF-II+/+ (MIG) mice, following beta cell injury. As expected in the presence of IGF-II beta cell mass and numbers recover rapidly after ablation. In contrast, in pIns-c-MycERTAM/IGF-II+/− (MIGKO) mice, which express no IGF-II, recovery of beta cell mass and numbers were delayed and impaired. Despite failure of beta cell number increase, MIGKO mice recovered from hyperglycaemia, although this was delayed. Conclusions/Significance Our results demonstrate that beta cell regeneration in adult mice depends on re-expression of IGF-II, and supports the utility of using such ablation-recovery models for identifying other potential factors critical for underpinning successful beta cell regeneration in vivo. The potential therapeutic benefits of manipulating the IGF-II signaling systems merit further exploration
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