Parent-offspring conflict and the genetic trade-offs shaping parental investment

The genetic conflict between parents and their offspring is a cornerstone of kin selection theory and the gene-centred view of evolution, but whether it actually occurs in natural systems remains an open question. Conflict operates only if parenting is driven by genetic trade-offs between offspring performance and the parent's ability to raise additional offspring, and its expression critically depends on the shape of these trade-offs. Here we investigate the occurrence and nature of genetic conflict in an insect with maternal care, the earwig Forficula auricularia. Specifically, we test for a direct response to experimental selection on female future reproduction and correlated responses in current offspring survival, developmental rate and growth. The results demonstrate genetic trade-offs that differ in shape before and after hatching. Our study not only provides direct evidence for parent-offspring conflict but also highlights that conflict is not inevitable and critically depends on the genetic trade-offs shaping parental investment.Peer reviewe

Towards a Fast Parallel Sparse Matrix-Vector Multiplication

this paper. We would also like to thank Rolf Strebel for explanatory discussions on the subject of software pipelining

The Chebyshev iteration revisited

Compared to Krylov space methods based on orthogonal or oblique projection, the Chebyshev iteration does not require inner products and is therefore particularly suited for massively parallel computers with high communication cost. We compare six different algorithms that implement this methods and compare them with respect to roundoff effects, in particular, the ultimately achievable accuracy. Two of these algorithms replace the three-term recurrences by more accurate coupled two-term recurrences and seem to be new. But we also show that, for real data, the classical three-term Chebyshev iteration is never seriously affected by roundoff, in contrast to the corresponding version of the conjugate gradient method. Even for complex data, strong roundoff effects are seen to be limited to very special situations where convergence is anyway slow. The Chebyshev iteration is applicable to symmetric definite linear systems and to nonsymmetric matrices whose eigenvalues are known to be confined to an elliptic domain that does not include the origin. We also consider a corresponding stationary 2-step method, which has the same asymptotic convergence behavior and is additionally suitable for mildly nonlinear problems

Variations of Zhang’s Lanczos-type product method

Abstract Among the Lanczos-type product methods, which are characterized by residual polynomials p n t n that are the product of the Lanczos polynomial p n and another polynomial t n of exact degree n with t n (0) = 1, Zhang's algorithm GPBICG has the feature that the polynomials t n are implicitly built up by a pair of coupled two-term recurrences whose coefficients are chosen so that the new residual is minimized in a 2-dimensional space. There are several ways to achieve this. We discuss here alternative algorithms that are mathematically equivalent (that is, produce in exact arithmetic the same results). The goal is to find one where the ultimate accuracy of the iterates x n is guaranteed to be high and the cost is at most slightly increased. 2001 IMACS. Published by Elsevier Science B.V. All rights reserved

2002, Recent advances in sparse linear solver technology for semiconductor device simulation matrices

Abstract-This paper discusses recent advances in the development of robust direct and iterative sparse linear solvers for general unsymmetric linear systems of equations. The primary focus is on robust methods for semiconductor device simulations matrices, but all methods presented are solely based on the structure of the matrices and can be applied to other application areas e.g. circuit simulation. Reliability, a low memory-footprint, and a short solution time are important demands for the linear solver. Currently, no black-box solver exists that can satisfy all criteria. The linear systems from semiconductor device simulations can be highly ill-conditioned and therefore quite challenging for direct and preconditioned iterative solver. In this paper, it is shown that nonsymmetric permutations and scalings aimed at placing large entries on the diagonal greatly enhance the reliability of direct and iterative methods. The numerical experiments indicate that the overall solution strategy is both reliable and very cost effective. The paper also compares the performance of some common software packages for solving general sparse systems

The Chebyshev iteration revisited

Compared to Krylov space methods based on orthogonal or oblique projection, the Chebyshev iteration does not require inner products and is therefore particularly suited for massively parallel computers with high communication cost. Here, six dierent algorithms that implement this method are presented and compared with respect to roundo eects, in particular, the ultimately achievable accuracy. Two of these algorithms replace the three-term recurrences by more accurate coupled two-term recurrences and seem to be new. It is also shown that, for real data, the classical three-term Chebyshev iteration is never seriously aected by roundo, in contrast to the corresponding version of the conjugate gradient method. Even for complex data, strong roundo eects are seen to be limited to very special situations where convergence is anyway slow. The Chebyshev iteration is applicable to symmetric denite linear systems and to nonsymmetric matrices whose eigenvalues are known to be conned to an elliptic domain that does not include the origin. Also considered is a corresponding stationary 2-step method, which has the same asymptotic convergence behavior and is additionally suitable for mildly nonlinear problems. Key words: sparse linear systems, Chebyshev iteration, second order Richarson iteration, coupled two-term recurrences, roundo error analysis 1991 MSC: 65F10, 65G05, 65H10 1 Email: [email protected], URL: http://www.sam.math.ethz.ch/mhg 2 Email: [email protected] Preprint submitted to Elsevier Science 24 July 2001

Sensitivity of DF-ICP-MS, PERALS and alpha-spectrometry for the determination of actinides: A comparison

We applied three techniques (DF-ICP-MS, PERALS and alpha-spectrometry) for the determination of minor actinides at environmental levels. For each method the limit of detection and the resolution were estimated in order to study the content and isotopic composition of the actinides. Two international reference materials, IAEA-135 (Irish Sea Sediment) and IAEA-300 (Baltic Sea sediment) were analyzed for activity concentrations of 238Pu, 239Pu, 240Pu, 241Pu and 241Am. The sensitivities of the three determination techniques were compared