1,241 research outputs found

    Cooking with Roots: How Older Adults Strengthen Connection with Younger Generations Through Recipe Sharing

    Get PDF
    This research investigates how older adults experience sharing recipes with younger generations, and examines conditions that contribute to the expression of generativity within the context of intergenerational recipe sharing. In Study 1, semi-structured interviews centered on experiences with intergenerational recipe sharing will be conducted with 30 older adults (age 65+). Participants will complete a survey of generative concern before and after engaging in a basic recipe sharing task. In line with previous research on generative art activities, responses will highlight feelings of autonomy as well as desires to teach others and leave a legacy. It is also hypothesized that generative concern will increase as a consequence of the recipe sharing task. Following preliminary research, Study 2 will examine how recipe type (special occasion vs. everyday-style recipe), mode of sharing (oral vs. written), and identity of recipe recipient (relative vs. stranger) influence generative concern in 792 older adults. Participants will complete the same survey described in Study 1 before being randomly assigned to one of eight recipe sharing tasks. After three sharing sessions, participants will be re-tested for present and future-oriented generativity. While all groups will show an increase in generativity over time, participants who share recipes with a younger relative and those who share recipes orally will benefit more from the intervention than their counterparts. Results will suggest that generativity is dependent on factors of recipe type, mode of sharing, and recipe recipient when recipes are passed from one generation to another. Implications and further directions are discussed, including intergenerational learning, well-being, and ego integrity in late life

    Intermediate inflation and the slow-roll approximation

    Full text link
    It is shown that spatially homogeneous solutions of the Einstein equations coupled to a nonlinear scalar field and other matter exhibit accelerated expansion at late times for a wide variety of potentials VV. These potentials are strictly positive but tend to zero at infinity. They satisfy restrictions on V/VV'/V and V/VV''/V' related to the slow-roll approximation. These results generalize Wald's theorem for spacetimes with positive cosmological constant to those with accelerated expansion driven by potentials belonging to a large class.Comment: 19 pages, results unchanged, additional backgroun

    Cosmology with positive and negative exponential potentials

    Get PDF
    We present a phase-plane analysis of cosmologies containing a scalar field ϕ\phi with an exponential potential Vexp(λκϕ)V \propto \exp(-\lambda \kappa \phi) where κ2=8πG\kappa^2 = 8\pi G and VV may be positive or negative. We show that power-law kinetic-potential scaling solutions only exist for sufficiently flat (λ26\lambda^26) negative potentials. The latter correspond to a class of ever-expanding cosmologies with negative potential. However we show that these expanding solutions with a negative potential are to unstable in the presence of ordinary matter, spatial curvature or anisotropic shear, and generic solutions always recollapse to a singularity. Power-law kinetic-potential scaling solutions are the late-time attractor in a collapsing universe for steep negative potentials (the ekpyrotic scenario) and stable against matter, curvature or shear perturbations. Otherwise kinetic-dominated solutions are the attractor during collapse (the pre big bang scenario) and are only marginally stable with respect to anisotropic shear.Comment: 8 pages, latex with revtex, 9 figure

    Closed cosmologies with a perfect fluid and a scalar field

    Get PDF
    Closed, spatially homogeneous cosmological models with a perfect fluid and a scalar field with exponential potential are investigated, using dynamical systems methods. First, we consider the closed Friedmann-Robertson-Walker models, discussing the global dynamics in detail. Next, we investigate Kantowski-Sachs models, for which the future and past attractors are determined. The global asymptotic behaviour of both the Friedmann-Robertson-Walker and the Kantowski-Sachs models is that they either expand from an initial singularity, reach a maximum expansion and thereafter recollapse to a final singularity (for all values of the potential parameter kappa), or else they expand forever towards a flat power-law inflationary solution (when kappa^2<2). As an illustration of the intermediate dynamical behaviour of the Kantowski-Sachs models, we examine the cases of no barotropic fluid, and of a massless scalar field in detail. We also briefly discuss Bianchi type IX models.Comment: 15 pages, 10 figure

    Accelerated cosmological expansion due to a scalar field whose potential has a positive lower bound

    Full text link
    In many cases a nonlinear scalar field with potential VV can lead to accelerated expansion in cosmological models. This paper contains mathematical results on this subject for homogeneous spacetimes. It is shown that, under the assumption that VV has a strictly positive minimum, Wald's theorem on spacetimes with positive cosmological constant can be generalized to a wide class of potentials. In some cases detailed information on late-time asymptotics is obtained. Results on the behaviour in the past time direction are also presented.Comment: 16 page

    Scaling Solutions in Robertson-Walker Spacetimes

    Full text link
    We investigate the stability of cosmological scaling solutions describing a barotropic fluid with p=(γ1)ρp=(\gamma-1)\rho and a non-interacting scalar field ϕ\phi with an exponential potential V(\phi)=V_0\e^{-\kappa\phi}. We study homogeneous and isotropic spacetimes with non-zero spatial curvature and find three possible asymptotic future attractors in an ever-expanding universe. One is the zero-curvature power-law inflation solution where Ωϕ=1\Omega_\phi=1 (γ2/3,κ2<2\gamma2/3,\kappa^2<2). Another is the zero-curvature scaling solution, first identified by Wetterich, where the energy density of the scalar field is proportional to that of matter with Ωϕ=3γ/κ2\Omega_\phi=3\gamma/\kappa^2 (γ3γ\gamma3\gamma). We find that this matter scaling solution is unstable to curvature perturbations for γ>2/3\gamma>2/3. The third possible future asymptotic attractor is a solution with negative spatial curvature where the scalar field energy density remains proportional to the curvature with Ωϕ=2/κ2\Omega_\phi=2/\kappa^2 (γ>2/3,κ2>2\gamma>2/3,\kappa^2>2). We find that solutions with Ωϕ=0\Omega_\phi=0 are never late-time attractors.Comment: 8 pages, no figures, latex with revte

    Anisotropic Power-law Inflation

    Full text link
    We study an inflationary scenario in supergravity model with a gauge kinetic function. We find exact anisotropic power-law inflationary solutions when both the potential function for an inflaton and the gauge kinetic function are exponential type. The dynamical system analysis tells us that the anisotropic power-law inflation is an attractor for a large parameter region.Comment: 14 pages, 1 figure. References added, minor corrections include
    corecore