4,041 research outputs found

    Large Scale Reasoning Using Allen's Interval Algebra

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    This paper proposes and evaluates a distributed, parallel approach for reasoning over large scale datasets using Allen's Interval Algebra (IA). We have developed and implemented algorithms that reason over IA networks using the Spark distributed processing framework. Experiments have been conducted by deploying the algorithms on computer clusters using synthetic datasets with various characteristics. We show that reasoning over datasets consisting of millions of interval relations is feasible and that our implementation scales effectively. The size of the IA networks we are able to reason over is far greater than those found in previously published works

    Whither Capitalism? Financial externalities and crisis

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    As with global warming, so with financial crises – externalities have a lot to answer for. We look at three of them. First the financial accelerator due to ‘fire sales’ of collateral assets -- a form of pecuniary externality that leads to liquidity being undervalued. Second the ‘risk- shifting’ behaviour of highly-levered financial institutions who keep the upside of risky investment while passing the downside to others thanks to limited liability. Finally, the network externality where the structure of the financial industry helps propagate shocks around the system unless this is checked by some form of circuit breaker, or ‘ring-fence’. The contrast between crisis-induced Great Recession and its aftermath of slow growth in the West and the rapid - and (so far) sustained - growth in the East suggests that successful economic progress may depend on how well these externalities are managed

    The impact of distance and a shifting temperature gradient on genetic connectivity across a heterogeneous landscape

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    <p>Abstract</p> <p>Background</p> <p>Inter-population distance and differences in breeding times are barriers to reproduction that can contribute to genotypic differentiation between populations. Temporal changes in environmental conditions and local selective processes can further contribute to the establishment of reproductive barriers. <it>Telopea speciosissima </it>(Proteaceae) is an excellent subject for studying the effect of geographic, edaphic and phenological heterogeneity on genotypic differentiation because previous studies show that these factors are correlated with morphological variation. Molecular, morphological and environmental datasets were combined to characterise the relative influence of these factors on inter-population differentiation, and Bayesian analyses were used to investigate current levels of admixture between differentiated genomes.</p> <p>Results</p> <p>A landscape genetic approach involving molecular and morphological analyses identified three endpoints of differentiated population groups: coastal, upland and southern. The southern populations, isolated from the other populations by an edaphic barrier, show low migration and no evidence of admixture with other populations. Amongst the northern populations, coastal and upland populations are connected along a skewed altitudinal gradient by genetically intermediate populations. The strong association between temperature and flowering time in <it>Telopea speciosissima </it>was shown to maintain a temporally unstable reproductive barrier between coastal and upland populations.</p> <p>Conclusions</p> <p>Substrate-mediated allopatry appears to be responsible for long-term genetic isolation of the southern populations. However, the temperature-dependent reproductive barrier between upland and coastal populations bears the genetic signature of temporal adjustments. The extreme climatic events of the last glacial maximum are likely to have caused more complete allochronic isolation between upland and coastal populations, as well as exerting increased selective pressure upon local genomes. However, at intermediate altitudes, current climatic conditions allow for the incorporation of alleles from previously distinct genomes, generating new, intermediate genomic assemblages and possibly increasing overall adaptive potential.</p

    Searching (the) FIRST radio arcs near ACO clusters

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    Gravitational lensing (GL) of distant radio sources by galaxy clusters should produce radio arc(let)s. We extracted radio sources from the FIRST survey near Abell cluster cores and found their radio position angles to be uniformly distributed with respect to the cluster centres. This result holds even when we restrict the sample to the richest or most centrally condensed clusters, and to sources with high S/N and large axial ratio. Our failure to detect GL with statistical methods may be due to poor cluster centre positions. We did not find convincing candidates for arcs either. Our result agrees with theoretical estimates predicting that surveys much deeper than FIRST are required to detect the effect. This is in apparent conflict with the detection of such an effect claimed by Bagchi & Kapahi (1995).Comment: 6 pages; 8 figures and 1 style file are included; to appear in Proc. "Observational Cosmology with the New Radio Surveys", eds. M. Bremer, N. Jackson & I. Perez-Fournon, Kluwer Acad. Pres

    Lekner summations and Ewald summations for quasi-two dimensional systems

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    Using the specific model of a bilayer of classical charged particles (bilayer Wigner crystal), we compare the predictions for energies and pair distribution functions obtained by Monte Carlo simulations using three different methods available to treat the long range Coulomb interactions in systems periodic in two directions but bound in the third one. The three methods compared are: the Ewald method for quasi-two dimensional systems [D.E. Parry, Surf. Sci. 49\bm{49}, 433 (1975); \it{ibid.}, 54\bm{54}, 195 (1976)], the Hautman-Klein method [J. Hautman and M.L. Klein, Mol. Phys. 75\bm{75}, 379 (1992)] and the Lekner summations method [J. Lekner, Physica A176\bm{176}, 485 (1991)]. All of the three method studied in this paper may be applied to any quasi-two dimensional systems, including those having not the specific symmetry of slab systems. For the particular system used in this work, the Ewald method for quasi-two dimensional systems is exact and may be implemented with efficiency; results obtained with the other two methods are systematically compared to results found with the Ewald method. General recommendations to implement with accuracy, but not always with efficiency, the Lekner summations technique in Monte Carlo algorithms are given.Comment: 50 pages, 9 figures, 4 table

    Pain education for adolescents and young adults living beyond cancer: An interdisciplinary meeting report

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    © Copyright 2019, Mary Ann Liebert, Inc., publishers 2019. Pain is an understudied and undertreated consequence of cancer survival. Pain education is now a recommended treatment approach for persistent non-cancer pain, yet it has not been well applied to the context of adolescent and young adult (AYA) cancer survival. In March 2018, an interdisciplinary meeting was held in Adelaide, South Australia to set a research agenda for pain education in AYA cancer survivors. We identified that AYAs with persistent pain and those with heightened pain-related fear have the potential to benefit from pain education. We identified a number of unique challenges of engaging AYA survivors in pain education, and point towards future research directions

    Anesthesia for intra-articular corticosteroid injections in juvenile idiopathic arthritis: A survey of pediatric rheumatologists

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    <p>Abstract</p> <p>Objective</p> <p>To determine the methods of anesthesia currently being used by pediatric rheumatologists when performing intra-articular corticosteroid injections (IACI).</p> <p>Study design</p> <p>A questionnaire was emailed to all members of the Childhood Arthritis & Rheumatology Research Alliance, a pediatric rheumatology research network in North America. The questionnaire consisted of 11 questions ranging from procedure technique, treatments prescribed for topical anesthesia and oral analgesia, and factors that might affect procedural pain.</p> <p>Results</p> <p>Seventy-four of 161 physicians (46%) responded to the questionnaire. On average, each physician injected 33 children (median 25, range 1-160) and 43 joints (median 30, range 1-150) yearly. Local anesthesia was used in children on average ≥ 8 years (range 2-16 years), with general anesthesia being more frequently used for younger children. All respondents used local anesthesia. The most commonly used methods of local anesthesia were EMLA<sup>® </sup>cream plus subcutaneous lidocaine (58.8%), ethyl chloride spray only (39.7%), EMLA<sup>® </sup>cream only (33.8%), subcutaneous lidocaine only (25%), and lidocaine iontophoresis only (11.8%). Buffering of the lidocaine was routinely done only 7.4% of the time.</p> <p>Conclusion</p> <p>Although pediatric rheumatologists in North America perform IACI on a large number of patients each year, a wide variety of methods are used to deliver local anesthesia with no accepted standard of care. More studies are needed to determine the optimal method of local anesthesia delivery to minimize pain associated with IACI.</p

    Loneliness, social support and cardiovascular reactivity to laboratory stress

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    Self-reported or explicit loneliness and social support have been inconsistently associated with cardiovascular reactivity (CVR) to stress. The present study aimed to adapt an implicit measure of loneliness, and use it alongside the measures of explicit loneliness and social support, to investigate their correlations with CVR to laboratory stress. Twenty-five female volunteers aged between 18 and 39 years completed self-reported measures of loneliness and social support, and an Implicit Association Test (IAT) of loneliness. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) reactivity indices were measured in response to psychosocial stress induced in the laboratory. Functional support indices of social support were significantly correlated with CVR reactivity to stress. Interestingly, implicit, but not explicit, loneliness was significantly correlated with DBP reactivity after one of the stressors. No associations were found between structural support and CVR indices. Results are discussed in terms of validity of implicit versus explicit measures and possible factors that affect physiological outcomes

    Comets, historical records and vedic literature

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    A verse in book I of Rigveda mentions a cosmic tree with rope-like aerial roots held up in the sky. Such an imagery might have ensued from the appearance of a comet having `tree stem' like tail, with branched out portions resembling aerial roots. Interestingly enough, a comet referred to as `heavenly tree' was seen in 162 BC, as reported by old Chinese records. Because of weak surface gravity, cometary appendages may possibly assume strange shapes depending on factors like rotation, structure and composition of the comet as well as solar wind pattern. Varahamihira and Ballala Sena listed several comets having strange forms as reported originally by ancient seers such as Parashara, Vriddha Garga, Narada and Garga. Mahabharata speaks of a mortal king Nahusha who ruled the heavens when Indra, king of gods, went into hiding. Nahusha became luminous and egoistic after absorbing radiance from gods and seers. When he kicked Agastya (southern star Canopus), the latter cursed him to become a serpent and fall from the sky. We posit arguments to surmise that this Mahabharata lore is a mythical recounting of a cometary event wherein a comet crossed Ursa Major, moved southwards with an elongated tail in the direction of Canopus and eventually went out of sight. In order to check whether such a conjecture is feasible, a preliminary list of comets (that could have or did come close to Canopus) drawn from various historical records is presented and discussed.Comment: This work was presented in the International Conference on Oriental Astronomy held at IISER, Pune (India) during November, 201
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