5,018 research outputs found

    A global inter-country economic model based on linked input-output models

    Get PDF
    We present a new, flexible and extensible alternative to multi-regional input-output (MRIO) for modelling the global economy. The limited coefficient set of MRIO (technical coefficients only) is extended to include two new sets of coefficients, import ratios and import propensities. These new coefficient sets assist in the interaction of the new model with other social science models such as those of trade, migration, international security and development aid. The model uses input-output models as descriptions of the internal workings of countries’ economies, and couples these more loosely than in MRIO using trade data for commodities and services from the UN. The model is constructed using a minimal number of assumptions, seeks to be as parsimonious as possible in terms of the number of coefficients, and is based to a great extent on empirical observation. Two new metrics are introduced, measuring sectors’ economic significance and economic self-reliance per country. The Chinese vehicles sector is shown to be the world’s most significant, and self-reliance is shown to be strongly correlated with population. The new model is shown to be equivalent to an MRIO under an additional assumption, allowing existing analysis techniques to be applied

    Binary companions of nearby supernova remnants found with Gaia

    Get PDF
    © ESO, 2017. Aims. We search for runaway former companions of the progenitors of nearby Galactic core-collapse supernova remnants (SNRs) in the Tycho-Gaia astrometric solution (TGAS). Methods. We look for candidates among a sample of ten SNRs with distances 2kpc, taking astrometry and G magnitude from TGAS and B,V magnitudes from the AAVSO Photometric All-Sky Survey (APASS). A simple method of tracking back stars and finding the closest point to the SNR centre is shown to have several failings when ranking candidates. In particular, it neglects our expectation that massive stars preferentially have massive companions. We evolve a grid of binary stars to exploit these covariances in the distribution of runaway star properties in colour - magnitude - ejection velocity space. We construct an analytic model which predicts the properties of a runaway star, in which the model paramet ers are the location in the grid of progenitor binaries and the properties of the SNR. Using nested sampling we calculate the Bayesian evidence for each candidate to be the runaway and simultaneously constrain the properties of that runaway and of the SNR itself. Results. We identify four likely runaway companions of the Cygnus Loop (G074.0-08.5), HB 21 (G089.0+ 04.7), S147 (G180.0+ 01.7) and the Monoceros Loop (G205.5+ 00.5). HD 37424 has previously been suggested as the companion of S147, however the other three stars are new candidates. The favoured companion of HB 21 is the Be star BD+50 3188 whose emission-line features could be explained by pre-supernova mass transfer from the primary. There is a small probability that the 2M candidate runaway TYC 2688-1556-1 associated with the Cygnus Loop is a hypervelocity star. If the Monoceros Loop is related to the on-going star formation in the Mon OB2 association, the progenitor of the Monoceros Loop is required to be more massive than 40M which is in tension with the posterior for our candidate runaway star HD 261393.DPB is grateful to the Science and Technology Facilities Council (STFC) for providing Ph.D. funding. M.F. is supported by a Royal Society – Science Foundation Ireland University Research Fellowship. This work was partly supported by the European Union FP7 programme through ERC grant number 320360. RGI thanks the STFC for funding his Rutherford fellowship under grant ST/L003910/1 and Churchill College, Cambridge for his fellowship

    Property in insolvent estates – Edkins V registrar of deeds, Fourie V Edkins, and Motala V Moller

    Get PDF
    The question of the ownership of property which vests (by virtue of sections 20(1) and 21(1) respectively of the Insolvency Act 24 of 1936) in the Master and, upon appointment, in the trustee of the insolvent estate, has been the source of academic debate and conflicting court judgments over a lengthy period. It was thought that the question had been finally settled by the (then) Appellate Division in De Villiers v Delta Cables (Pty) Ltd 1992 1 SA 9 (A), which concerned property belonging to the solvent spouse (as defined in section 21(13)), where it was held that ownership passes to the Master and subsequently the trustee. This was accepted by the Constitutional Court for the purposes of its judgment in Harksen v Lane 1998 1 SA 300 (CC). However, recent judgments, in Edkins v Registrar of Deeds, Johannesburg 2012 6 SA 278 (GSJ) and, on appeal, Fourie v Edkins 2013 6 SA 576 (SCA), have seemingly again opened up the question for debate, particularly in view of the fact that the Supreme Court of Appeal in Fourie v Edkins ignored its own precedent on this issue. These two judgments concerned property registered in the name of the insolvent. In a third recent judgment, in Motala v Moller (GSJ) unreported case number 32654/11 (GSJ) of 11 September 2013 (copy on file with authors) concerning property which had belonged to the solvent spouse at the time of the sequestration of the estate of her husband, the court regarded section 25(4) of the Insolvency Act as countering the precedent established by De Villiers v Delta Cables. In this article, each of these three judgments is analysed and criticised. &nbsp

    Access to Principal Treatment Centres and survival rates for children and young people with cancer in Yorkshire, UK

    Get PDF
    Background: Principal Treatment Centres (PTC) were established to provide age-appropriate care as well as clinical expertise for children and young people with cancer. However, little is known about the effects of specialist treatment centres on survival outcomes especially for teenagers and young adults. This population-based study aimed to describe access to PTC and the associated trends in survival for 0–24 year olds accounting for stage of disease at presentation and treatment. Methods: Patients diagnosed from 1998–2009 aged 0–24 years were extracted from the Yorkshire Specialist Register of Cancer in Children and Young People, including information on all treating hospitals, followed-up until 31st December 2014. The six commonest cancer types were included: leukaemia (n = 684), lymphoma (n = 558), CNS tumours (n = 547), germ cell tumours (n = 364), soft tissue sarcomas (n = 171) and bone tumours (n = 163). Treatment was categorised into three groups: ‘all’, ‘some’ or ‘no’ treatment received at a PTC. Treatment at PTC was examined by diagnostic group and patient characteristics. Overall survival was modelled using Cox regression adjusting for case-mix including stage, treatment and other socio-demographic and clinical characteristics. Results: Overall 72% of patients received all their treatment at PTC whilst 13% had no treatment at PTC. This differed by diagnostic group and age at diagnosis. Leukaemia patients who received no treatment at PTC had an increased risk of death which was partially explained by differences in patient case-mix (adjusted Hazard Ratio (HR) = 1.73 (95%CI 0.98–3.04)). Soft tissue sarcoma patients who had some or no treatment at PTC had better survival outcomes, which remained after adjustment for patient case-mix (adjusted HR = 0.48 (95%CI 0.23–0.99)). There were no significant differences in outcomes for other diagnostic groups (lymphoma, CNS tumours, bone tumours and germ cell tumours). For leukaemia patients survival outcomes for low risk patients receiving no treatment at PTC were similar to high risk patients who received all treatment at PTC, implying a benefit for care at the PTC. Conclusion: This study demonstrates that for leukaemia patients receiving treatment at a PTC is associated with improved survival that may compensate for a poorer prognosis presentation. However, further information on risk factors is needed for all diagnostic groups in order to fully account for differences in patient case-mix

    Absence of renal hypoxia in the subacute phase of severe renal ischemia reperfusion injury

    Get PDF
     This is the author accepted manuscript. The final version is available from American Physiological Society via the DOI in this recordTissue hypoxia has been proposed as an important event in renal ischemia reperfusion injury (IRI) particularly during the period of ischemia and in the immediate hours following reperfusion. However, little is known about renal oxygenation during the subacute phase of IRI. We employed four different methods to assess the temporal and spatial changes in tissue oxygenation during the subacute phase (24 h and 5 days after reperfusion) of a severe form of renal IRI in rats. We hypothesized that the kidney is hypoxic 24 h and 5 days after an hour of bilateral renal ischemia, driven by a disturbed balance between renal oxygen delivery (DO2) and oxygen consumption (VO2). Renal DO2 was not significantly reduced in the subacute phase of IRI. In contrast, renal VO2 was 55% less 24 h, and 49% less 5 days after reperfusion than after sham-ischemia. Inner medullary tissue PO2, measured by radiotelemetry was 25 {plus minus} 12% greater 24 h after ischemia than after sham-ischemia. By 5 days after reperfusion, tissue PO2 was similar to that in rats subjected to sham-ischemia. Tissue PO2 measured by Clark electrode was consistently greater 24 h, but not 5 days, after ischemia than after sham-ischemia. Cellular hypoxia, assessed by pimonidazole adduct immunohistochemistry, was largely absent at both time-points and tissue levels of hypoxia inducible factors were downregulated following renal ischemia. Thus, in this model of severe IRI, tissue hypoxia does not appear to be an obligatory event during the subacute phase, likely due to the markedly reduced oxygen consumption.British Heart FoundationBritish Heart FoundationNational Health and Medical Research Council of AustraliaEuropean Union, Seventh Framework Programm

    Hypervelocity runaways from the Large Magellanic Cloud

    Get PDF
    We explore the possibility that the observed population of Galactic hypervelocity stars (HVSs) originate as runaway stars from the Large Magellanic Cloud (LMC). Pairing a binary evolution code with an N-body simulation of the interaction of the LMC with the Milky Way, we predict the spatial distribution and kinematics of an LMC runaway population. We find that runaway stars from the LMC can contribute Galactic HVSs at a rate of 3 × 10¯⁶ yr‾¹. This is composed of stars at different points of stellar evolution, ranging from the main sequence to those at the tip of the asymptotic giant branch. We find that the known B-type HVSs have kinematics that are consistent with an LMC origin. There is an additional population of hypervelocity white dwarfs whose progenitors were massive runaway stars. Runaways that are even more massive will themselves go supernova, producing a remnant whose velocity will be modulated by a supernova kick. This latter scenario has some exotic consequences, such as pulsars and supernovae far from star-forming regions, and a small rate of microlensing from compact sources around the halo of the LMC.DB is grateful to the Science and Technology Facilities Council (STFC) for providing PhD funding. DE acknowledges that research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no. 308024. RGI thanks the STFC for funding his Rutherford fellowship under grant ST/L003910/1 and Churchill College, Cambridge for his fellowship

    Parameterized Complexity of the k-anonymity Problem

    Full text link
    The problem of publishing personal data without giving up privacy is becoming increasingly important. An interesting formalization that has been recently proposed is the kk-anonymity. This approach requires that the rows of a table are partitioned in clusters of size at least kk and that all the rows in a cluster become the same tuple, after the suppression of some entries. The natural optimization problem, where the goal is to minimize the number of suppressed entries, is known to be APX-hard even when the records values are over a binary alphabet and k=3k=3, and when the records have length at most 8 and k=4k=4 . In this paper we study how the complexity of the problem is influenced by different parameters. In this paper we follow this direction of research, first showing that the problem is W[1]-hard when parameterized by the size of the solution (and the value kk). Then we exhibit a fixed parameter algorithm, when the problem is parameterized by the size of the alphabet and the number of columns. Finally, we investigate the computational (and approximation) complexity of the kk-anonymity problem, when restricting the instance to records having length bounded by 3 and k=3k=3. We show that such a restriction is APX-hard.Comment: 22 pages, 2 figure

    Extending the applicability of the dose addition model to the assessment of chemical mixtures of partial agonists by using a novel toxic unit extrapolation method

    Get PDF
    This article has been made available through the Brunel Open Access Publishing Fund.Dose addition, a commonly used concept in toxicology for the prediction of chemical mixture effects, cannot readily be applied to mixtures of partial agonists with differing maximal effects. Due to its mathematical features, effect levels that exceed the maximal effect of the least efficacious compound present in the mixture, cannot be calculated. This poses problems when dealing with mixtures likely to be encountered in realistic assessment situations where chemicals often show differing maximal effects. To overcome this limitation, we developed a pragmatic solution that extrapolates the toxic units of partial agonists to effect levels beyond their maximal efficacy. We extrapolated different additivity expectations that reflect theoretically possible extremes and validated this approach with a mixture of 21 estrogenic chemicals in the E-Screen. This assay measures the proliferation of human epithelial breast cancers. We found that the dose-response curves of the estrogenic agents exhibited widely varying shapes, slopes and maximal effects, which made it necessary to extrapolate mixture responses above 14% proliferation. Our toxic unit extrapolation approach predicted all mixture responses accurately. It extends the applicability of dose addition to combinations of agents with differing saturating effects and removes an important bottleneck that has severely hampered the use of dose addition in the past. © 2014 Scholze et al

    Long Term Implications of Climate Change on Crop Planning

    Get PDF
    The effects of climate change have been much speculated on in the past few years. Consequently, there has been intense interest in one of its key issues of food security into the future. This is particularly so given population increase, urban encroachment on arable land, and the degradation of the land itself. Recently, work has been done on predicting precipitation and temperature for the next few decades as well as developing optimisation models for crop planning. Combining these together, this paper examines the effects of climate change on a large food producing region in Australia, the Murrumbidgee Irrigation Area. For time periods between 1991 and 2071 for dry, average and wet years, an analysis is made about the way that crop mixes will need to change to adapt for the effects of climate change. It is found that sustainable crop choices will change into the future, and that large-scale irrigated agriculture may become unviable in the region in all but the wettest years
    corecore