A benign juvenile environment reduces the strength of antagonistic pleiotropy and genetic variation in the rate of senescence

The environment can play an important role in the evolution of senescence because the optimal allocation between somatic maintenance and reproduction depends on external factors influencing life expectancy. The aims of this study were to experimentally test whether environmental conditions during early life can shape senescence schedules, and if so, to examine whether variation among individuals or genotypes with respect to the degree of ageing differs across environments. We tested life-history plasticity and quantified genetic effects on the pattern of senescence across different environments within a reaction norm framework by using an experiment on the three-spined stickleback (Gasterosteus aculeatus, Linnaeus) in which F1 families originating from a wild annual population experienced different temperature regimes. Male sticklebacks that had experienced a more benign environment earlier in life subsequently reduced their investment in carotenoid-based sexual signals early in the breeding season, and consequently senesced at a slower rate later in the season, compared to those that had developed under harsher conditions. This plasticity of ageing was genetically determined. Both antagonistic pleiotropy and genetic variation in the rate of senescence were evident only in the individuals raised in the harsher environment. The experimental demonstration of genotype-by-environment interactions influencing the rate of reproductive senescence provides interesting insights into the role of the environment in the evolution of life histories. The results suggest that benign conditions weaken the scope for senescence to evolve and that the dependence on the environment may maintain genetic variation under selection

The homotopy fixed point theorem and the Quillen-Lichtenbaum conjecture in hermitian K-theory

Let X be a noetherian scheme of finite Krull dimension, having 2 invertible in its ring of regular functions, an ample family of line bundles, and a global bound on the virtual mod-2 cohomological dimensions of its residue fields. We prove that the comparison map from the hermitian K-theory of X to the homotopy fixed points of K-theory under the natural Z/2-action is a 2-adic equivalence in general, and an integral equivalence when X has no formally real residue field. We also show that the comparison map between the higher Grothendieck-Witt (hermitian K-) theory of X and its \'etale version is an isomorphism on homotopy groups in the same range as for the Quillen-Lichtenbaum conjecture in K-theory. Applications compute higher Grothendieck-Witt groups of complex algebraic varieties and rings of 2-integers in number fields, and hence values of Dedekind zeta-functions.Comment: 17 pages, to appear in Adv. Mat

Quantification of coarse-graining error in Langevin and overdamped Langevin dynamics

In molecular dynamics and sampling of high dimensional Gibbs measures coarse-graining is an important technique to reduce the dimensionality of the problem. We will study and quantify the coarse-graining error between the coarse-grained dynamics and an effective dynamics. The effective dynamics is a Markov process on the coarse-grained state space obtained by a closure procedure from the coarse-grained coefficients. We obtain error estimates both in relative entropy and Wasserstein distance, for both Langevin and overdamped Langevin dynamics. The approach allows for vectorial coarse-graining maps. Hereby, the quality of the chosen coarse-graining is measured by certain functional inequalities encoding the scale separation of the Gibbs measure. The method is based on error estimates between solutions of (kinetic) Fokker-Planck equations in terms of large-deviation rate functionals

Note: Minnesota’s Proposed Same-sex Marriage Amendment: A Flamingly Unconstitutional Violation of Full Faith and Credit, Due Process, and Equal Protection

This note examines the constitutionality of Minnesota’s proposed marriage amendment. The note begins with a description of the recent national events leading up to the amendment’s proposal, followed by a discussion of the history of marriage in Minnesota, including passage of the Defense of Marriage Act in May 1997. Next, the note examines the language of Minnesota’s proposed marriage amendment and briefly addresses the process of amending state constitutional provisions. It then analyzes the proposed amendment’s constitutionality under the Full Faith and Credit Clause, the Due Process Clause, and the Equal Protection Clause of the United States Constitution. Finally, the note discusses Congress’s proposal of a Marriage Protection Act and the implications this would have on federal courts’ ability to review same-sex marriage controversies

Formation of Kuiper Belt Binaries

The discovery that a substantial fraction of Kuiper Belt objects (KBOs) exists in binaries with wide separations and roughly equal masses, has motivated a variety of new theories explaining their formation. Goldreich et al. (2002) proposed two formation scenarios: In the first, a transient binary is formed, which becomes bound with the aid of dynamical friction from the sea of small bodies (L^2s mechanism); in the second, a binary is formed by three body gravitational deflection (L^3 mechanism). Here, we accurately calculate the L^2s and L^3 formation rates for sub-Hill velocities. While the L^2s formation rate is close to previous order of magnitude estimates, the L^3 formation rate is about a factor of 4 smaller. For sub-Hill KBO velocities (v << v_H) the ratio of the L^3 to the L^2s formation rate is 0.05 (v/v_H) independent of the small bodies' velocity dispersion, their surface density or their mutual collisions. For Super-Hill velocities (v >> v_H) the L^3 mechanism dominates over the L^2s mechanism. Binary formation via the L^3 mechanism competes with binary destruction by passing bodies. Given sufficient time, a statistical equilibrium abundance of binaries forms. We show that the frequency of long-lived transient binaries drops exponentially with the system's lifetime and that such transient binaries are not important for binary formation via the L^3 mechanism, contrary to Lee et al. (2007). For the L^2s mechanism we find that the typical time, transient binaries must last, to form Kuiper Belt binaries (KBBs) for a given strength of dynamical friction, D, increases only logarithmically with D. Longevity of transient binaries only becomes important for very weak dynamical friction (i.e. D \lesssim 0.002) and is most likely not crucial for KBB formation.Comment: 20 pages, 3 figures, Accepted for publication in ApJ, correction of minor typo