5,800 research outputs found

    TONUITY: A NOVEL INDIVIDUAL-ORIENTED RETIREMENT PLAN

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    For insurance companies in Europe, the introduction of Solvency II leads to a tightening of rules for solvency capital provision. In life insurance, this especially affects retirement products that contain a significant portion of longevity risk (e.g., conventional annuities). Insurance companies might react by price increases for those products, and, at the same time, might think of alternatives that shift longevity risk (at least partially) to policyholders. In the extreme case, this leads to so-called tontine products where the insurance company’s role is merely administrative and longevity risk is shared within a pool of policyholders. From the policyholder’s viewpoint, such products are, however, not desirable as they lead to a high uncertainty of retirement income at old ages. In this article, we alternatively suggest a so-called tonuity that combines the appealing features of tontine and conventional annuity. Until some fixed age (the switching time), a tonuity’s payoff is tontine-like, afterwards the policyholder receives a secure payment of a (deferred) annuity. A tonuity is attractive for both the retiree (who benefits from a secure income at old ages) and the insurance company (whose capital requirements are reduced compared to conventional annuities). The tonuity is a possibility to offer tailor-made retirement products: using risk capital charges linked to Solvency II, we show that retirees with very low or very high risk aversion prefer a tontine or conventional annuity, respectively. Retirees with medium risk aversion, however, prefer a tonuity. In a utility-based framework, we therefore determine the optimal tonuity characterized by the critical switching time that maximizes the policyholder’s lifetime utility.</jats:p&gt

    Differences in glucose control, insulin sensitivity, and body composition between metabolically healthy and unhealthy people with obesity

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    Poster presented at the 2017 Health Sciences Research Day which was organized and sponsored by the University of Missouri School of Medicine Research Council and held on November 9, 2017.Obesity is a significant risk factor for cardiometabolic complications, including type 2 diabetes and cardiovascular disease. However, approximately 25% of individuals with obesity are seemingly protected from these complications (Wildman et al. Arch Intern Med, 168, 1617-24, 2008). The purpose of this study was to provide a careful characterization of body composition and metabolic function in people who are: (i) lean and metabolically normal (MNL); (ii) obese and metabolically-normal (MN)); and (iii) obese and metabolically-abnormal (MAO). (Introduction & study aims) Although the glycemic responses of MNL individuals demonstrate a "metabolically healthy" state, more rigorous measures of insulin sensitivity show insulin resistance in this population, demonstrating people with MNO are insulin-resistant with respect to glucose metabolism but are able to maintain normal glycemic control by increased insulin secretion. Adipose tissue distribution is a marker of metabolic health in people with obesity, as greater intra-abdominal adipose tissue volume and intrahepatic triglyceride content are associated with metabolic dysfunction

    Consequences of the peculiar intrinsic properties of MgB2 on its macroscopic current flow

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    The influence of two important features of magnesium diboride on the macroscopic transport properties of polycrystalline MgB2 is discussed in the framework of a percolation model. While two band superconductivity does not have significant consequences in the field and temperature range of possible power applications, the opposite is true for the anisotropy of the upper critical field. The field dependence of the critical current densities strongly increases and the macroscopic supercurrents disappear well below the apparent upper critical field. The common scaling laws for the field dependence of the volume pinning force are altered and Kramer's plot is no longer linear, although grain boundary pinning dominates in nearly all polycrystalline MgB2 conductors. In contrast to the conventional superconductors NbTi and Nb3Sn, a significant critical current anisotropy can be induced by the preparation technique of MgB2 tapes

    Eomesodermin, a target gene of Pou4f2, is required for retinal ganglion cell and optic nerve development in the mouse.

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    The mechanisms regulating retinal ganglion cell (RGC) development are crucial for retinogenesis and for the establishment of normal vision. However, these mechanisms are only vaguely understood. RGCs are the first neuronal lineage to segregate from pluripotent progenitors in the developing retina. As output neurons, RGCs display developmental features very distinct from those of the other retinal cell types. To better understand RGC development, we have previously constructed a gene regulatory network featuring a hierarchical cascade of transcription factors that ultimately controls the expression of downstream effector genes. This has revealed the existence of a Pou domain transcription factor, Pou4f2, that occupies a key node in the RGC gene regulatory network and that is essential for RGC differentiation. However, little is known about the genes that connect upstream regulatory genes, such as Pou4f2 with downstream effector genes responsible for RGC differentiation. The purpose of this study was to characterize the retinal function of eomesodermin (Eomes), a T-box transcription factor with previously unsuspected roles in retinogenesis. We show that Eomes is expressed in developing RGCs and is a mediator of Pou4f2 function. Pou4f2 directly regulates Eomes expression through a cis-regulatory element within a conserved retinal enhancer. Deleting Eomes in the developing retina causes defects reminiscent of those in Pou4f2(-/-) retinas. Moreover, myelin ensheathment in the optic nerves of Eomes(-/-) embryos is severely impaired, suggesting that Eomes regulates this process. We conclude that Eomes is a crucial regulator positioned immediately downstream of Pou4f2 and is required for RGC differentiation and optic nerve development

    Regional astrocyte IFN signaling restricts pathogenesis during neurotropic viral infection

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    Type I IFNs promote cellular responses to viruses, and IFN receptor (IFNAR) signaling regulates the responses of endothelial cells of the blood-brain barrier (BBB) during neurotropic viral infection. However, the role of astrocytes in innate immune responses of the BBB during viral infection of the CNS remains to be fully elucidated. Here, we have demonstrated that type I IFNAR signaling in astrocytes regulates BBB permeability and protects the cerebellum from infection and immunopathology. Mice with astrocyte-specific loss of IFNAR signaling showed decreased survival after West Nile virus infection. Accelerated mortality was not due to expanded viral tropism or increased replication. Rather, viral entry increased specifically in the hindbrain of IFNAR-deficient mice, suggesting that IFNAR signaling critically regulates BBB permeability in this brain region. Pattern recognition receptors and IFN-stimulated genes had higher basal and IFN-induced expression in human and mouse cerebellar astrocytes than did cerebral cortical astrocytes, suggesting that IFNAR signaling has brain region–specific roles in CNS immune responses. Taken together, our data identify cerebellar astrocytes as key responders to viral infection and highlight the existence of distinct innate immune programs in astrocytes from evolutionarily disparate regions of the CNS

    Coherent long-range transfer of angular momentum between magnon Kittel modes by phonons

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    We report ferromagnetic resonance in the normal configuration of an electrically insulating magnetic bilayer consisting of two yttrium iron garnet (YIG) films epitaxially grown on both sides of a 0.5-mm-thick nonmagnetic gadolinium gallium garnet (GGG) slab. An interference pattern is observed and it is explained as the strong coupling of the magnetization dynamics of the two YIG layers either in phase or out of phase by the standing transverse sound waves, which are excited through a magnetoelastic interaction. This coherent mediation of angular momentum by circularly polarized phonons through a nonmagnetic material over macroscopic distances can be useful for future information technologies

    Can we (control) Engineer the degree learning process?

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    This paper investigates how control theory could be applied to learning processes in engineering education. The initial point for the analysis is White’s Double Loop learning model of human automation control modified for the education process where a set of governing principals is chosen, probably by the course designer. After initial training the student decides unknowingly on a mental map or model. After observing how the real world is behaving, a strategy to achieve the governing variables is chosen and a set of actions chosen. This may not be a conscious operation, it maybe completely instinctive. These actions will cause some consequences but not until a certain time delay. The current model is compared with the work of Hollenbeck on goal setting, Nelson’s model of self-regulation and that of Abdulwahed, Nagy and Blanchard at Loughborough who investigated control methods applied to the learning process

    de Haas-van Alphen effect investigations of the electronic structure of pure and aluminum-doped MgB_2

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    Understanding the superconducting properties of MgB_2 is based strongly on knowledge of its electronic structure. In this paper we review experimental measurements of the Fermi surface parameters of pure and Al-doped MgB_2 using the de Haas-van Alphen (dHvA) effect. In general, the measurements are in excellent agreement with the theoretical predictions of the electronic structure, including the strength of the electron-phonon coupling on each Fermi surface sheet. For the Al doped samples, we are able to measure how the band structure changes with doping and again these are in excellent agreement with calculations based on the virtual crystal approximation. We also review work on the dHvA effect in the superconducting state.Comment: Contribution to the special issue of Physica C "Superconductivity in MgB2: Physics and Applications" (10 Pages with figures

    Outcomes and Cost-Effectiveness of Two Nicotine Replacement Treatment Delivery Models for a Tobacco Quitline

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    Many tobacco cessation quitlines provide nicotine replacement therapy (NRT) in the U.S. but consensus is lacking regarding the best shipping protocol or NRT amounts. We evaluated the impact of the Minnesota QUITPLAN® Helpline’s shift from distributing NRT using a single eight-week shipment to a two-shipment protocol. For this observational study, the eight week single-shipment cohort (n = 247) received eight weeks of NRT (patches or gum) at once, while the split-shipment cohort (n = 160) received five weeks of NRT (n = 94), followed by an additional three weeks of NRT if callers continued with counseling (n = 66). Patient satisfaction, retention, quit rates, and cost associated with the three groups were compared. A higher proportion of those receiving eight weeks of NRT, whether in one or two shipments, reported that the helpline was “very helpful” (77.2% of the single-shipment group; 81.1% of the two-shipment group) than those receiving five weeks of NRT (57.8% of the one-shipment group) (p = 0.004). Callers in the eight week two-shipment group completed significantly more calls (3.0) than callers in the five week one-shipment group (2.4) or eight week single-shipment group (1.7) (p < 0.001). Using both responder and intent-to-treat calculations, there were no significant differences in 30-day point prevalence abstinence at seven months among the three protocol groups even when controlling for demographic and tobacco use characteristics, and treatment group protocol. The mean cost per caller was greater for the single-shipment phase than the split-shipment phase (350vs.350 vs. 326) due to the savings associated with not sending a second shipment to some participants. Assuming no difference in abstinence rates resulting from the protocol change, cost-per-quit was lowest for the five week one-shipment group (1,155),andlowerforthecombinedsplitshipmentcohort(1,155), and lower for the combined split-shipment cohort (1,242) than for the single-shipment cohort ($1,350). Results of this evaluation indicate that while satisfaction rates increase among those receiving more counseling and NRT, quit rates do not, even when controlling for demographic and tobacco use characteristics

    Effects of C, Cu and Be substitutions in superconducting MgB2

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    Density functional calculations are used to investigate the effects of partial substitutional alloying of the B site in MgB2 with C and Be alone and combined with alloying of the Mg site with Cu. The effect of such substitutions on the electronic structure, electron phonon coupling and superconductivity are discussed. We find that Be substitution for B is unfavorable for superconductivity as it leads to a softer lattice and weaker electron-phonon couplings. Replacement of Mg by Cu leads to an increase in the stiffness and doping level at the same time, while the carrier concentration can be controlled by partial replacement of B by C. We estimate that with full replacement of Mg by Cu and fractional substitution of B by C, Tc values of 50K may be attainable.Comment: 5 pages, 4 figure
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