257 research outputs found

    Balancing the book: Is it necessary and sufficient?

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    The solvency of bookmakers has only recently been placed in the spotlight even if it is a multibillion dollar sector. It is industry knowledge that bookmakers attempt to 'balance the book' by adjusting odds in relation to wagers made. This paper proves that the only way that profits are known with certainty is if and only if wagers are in proportion to probabilities implied by odds

    Additively manufactured CuCrZr alloy: improvement of mechanical properties by heat treatment

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    CuCrZr alloy plays a fundamental role for the production of critical components because it is characterized by good thermal and electrical conductivity and by high mechanical strength after precipitation hardening treatment. In the framework of a wider research on the mechanical behaviour of additively manufactured CuCrZr alloy, this study focuses on the effects of heat treatment parameters on the alloy strength. The additive manufacturing process, characterized by very high cooling rates, determines the formation, in the as-built condition, of a supersaturated solid solution. The results obtained reveal that aging temperature and time are critical parameters for improving the mechanical behaviour of CuCrZr alloy which behaves differently than the alloy produced through the use of traditional techniques

    A nonlinear random walk approach to concentration-dependent contaminant transport in porous media

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    We propose a nonlinear random walk model to describe the dynamics of dense contaminant plumes in porous media. A coupling between concentration and velocity fields is found, so that transport displays non-Fickian features. The qualitative behavior of the pollutant spatial profiles and moments is explored with the help of Monte Carlo simulation, within a Continuous Time Random Walk approach. Model outcomes are then compared with experimental measurements of variable-density contaminant transport in homogeneous and saturated vertical columns.Comment: 8 pages, 9 figure

    Changes in growth hormone receptor gene expression during therapy in children with juvenile idiopathic arthritis.

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    Background: High levels of cytokines in juvenile idiopathic arthritis (JIA) can alter target cell sensitivity to growth hormone (GH) leading to short stature in adulthood. We hypothesized that the down-regulation of GH receptor (GHR) gene expression could be involved in growth failure of children with JIA. Methods: In 18 (12 F and 6 M) prepubertal JIA patients and 13 age- and sex-matched healthy children, we evaluated serum growth-promoting factors and inflammatory indexes. We also measured GHR gene expression, by real-time PCR, in lymphocytes of patients and controls. All parameters were evaluated in patients before and after treatment of JIA. Results: The most interesting (p = 0.007) result was the increase in GHR mRNA expression in all JIA patients. Moreover, we observed a significant (p = 0.0156) decrease in IL-6 levels in JIA patients after 2 years of therapy (19.37 +/- 41.01) with respect to basal values (90.84 +/- 124.71). On the contrary, IGF-I significantly (p = 0.0005) increased to a mean SDS value of 0 (range -1.69 to +1.70 SDS) with respect to values at disease onset (-0.64 SDS). Conclusions: Our preliminary data suggest that the restoration of both GHR gene expression and IGF-I secretion correlate with inactive disease in JIA children

    An efficient and locking-free material point method for three dimensional analysis with simplex elements

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    The Material Point Method is a relative newcomer to the world of solid mechanicsmodelling. Its key advantage is the ability to model problems having large defor-mations while being relatively close to standard nite element methods, howeverits use for realistic engineering applications will happen only if the material pointcan be shown to be both ecient and accurate (compared to standard nite elementmethods), when modelling complex geometries with a range of material models. Inthis paper we present developments of the standard material point method aimed atrealising these goals. The key contribution provided here is the development of amaterial point method that avoids volumetric locking (arising from elastic or elasto-plastic material behaviour) whilst using low order tetrahedral nite elements forthe background computational mesh, hence allowing unstructured background gridsto be used for complex geometries. We also show that these developments can beeectively parallelised to improve computational ecienc
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