43 research outputs found

    Alternating hemiplegia of childhood or familial hemiplegic migraine?: A novel ATP1A2 mutation

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    Alternating hemiplegia of childhood (AHC) is typically distinguished from familial hemiplegic migraine (FHM) by infantile onset of the characteristic symptoms and high prevalence of associated neurological deficits that become increasingly obvious with age. Expansion of the clinical spectrum in FHM recently has begun to blur the distinction between these disorders. We report a novel ATP1A2 mutation in a kindred with features that bridge the phenotypic spectrum between AHC and FHM syndromes, supporting a possible common pathogenesis in a subset of such cases. Mutation analysis in classic sporadic AHC patients and in an additional five kindreds in which linkage to the A TP1A2 locus could not be excluded failed to identify additional mutations

    Optimal Insurance Design Under a Value-at-Risk Framework

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    This study designs an optimal insurance policy form endogenously, assuming the objective of the insured is to maximize expected final wealth under the Value-at-Risk (VaR) constraint. The optimal insurance policy can be replicated using three options, including a long call option with a small strike price, a short call option with a large strike price, and a short cash-or-nothing call option. Additionally, this study also calculates the optimal insurance levels for these models when we restrict the indemnity to be one of three common forms: a deductible policy, an upper-limit policy, or a policy with proportional coinsurance. Copyright Springer Science + Business Media, Inc. 2005value at risk, optimal insurance, deductible, policy limit, coinsurance,

    GRACES observations of young [α/Fe]-rich stars

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    We measure chemical abundance ratios and radial velocities in four massive (i.e. young) [α/Fe]-rich red giant stars using high-resolution high-S/N spectra from ESPaDOnS fed by Gemini-GRACES. Our differential analysis ensures that our chemical abundances are on the same scale as the Alves-Brito et al. (2010) study of bulge, thin, and thick disc red giants. We confirm that the program stars have enhanced [α/Fe] ratios and are slightly metal poor. Aside from lithium enrichment in one object, the program stars exhibit no chemical abundance anomalies when compared to giant stars of similar metallicity throughout the Galaxy. This includes the elements Li, O, Si, Ca, Ti, Cr, Ni, Cu, Ba, La, and Eu. Therefore, there are no obvious chemical signatures that can help to reveal the origin of these unusual stars. While our new observations show that only one star (not the Li-rich object) exhibits a radial velocity variation, simulations indicate that we cannot exclude the possibility that all four could be binaries. In addition, we find that two (possibly three) stars show evidence for an infrared excess, indicative of a debris disc. This is consistent with these young [α/Fe]-rich stars being evolved blue stragglers, suggesting their apparent young age is a consequence of a merger or mass transfer. We would expect a binary fraction of ∼50 per cent or greater for the entire sample of these stars, but the signs of the circumbinary disc may have been lost since these features can have short time-scales. Radial velocity monitoring is needed to confirm the blue straggler origin
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