Twice Chosen: Spouse Matching and Earnings Among Women in First and Second Marriages

This study examines spousal matching for females in second-order marriages. It is based on detailed data from longitudinal Swedish population data registers. We aim to follow women who marry, divorce, and subsequently remarry compared with females who marry and stay married over the course of the study interval. The earnings of both groups are modeled through regression analysis in the year prior to their marriages along with the earnings of each husband. The residuals from the regressions represent unobservables in the process of earnings generation. From the regressions we obtain spouse-to-be pairs of earnings residuals and we measure the correlation of residuals for each marital regime. Overall, we find significant positive correlations for all three of the marital partitions. The correlation tends to be smaller for the first of a sequence of marriages for women who divorce than for women who marry and stay so. For the second of the successive marriages, however, the correlation of the residuals is larger than that for women who marry but once. We also find evidence of “matching” between successive husbands. Women who marry men with unmeasured positive earnings capacities, in the event of divorce, tend to select and match in a similar fashion the second time around.Marital matching; Remarriage; Assortative mating; Earnings

Roughening of a propagating planar crack front

A numerical model of the front of a planar crack propagating between two connected elastic plates is investigated. The plates are modeled as square lattices of elastic beams. The plates are connected by similar but breakable beams with a randomly varying stiffness. The crack is driven by pulling both plates at one end in Mode I at a constant rate. We find ζ=1/3, z=4/3, and β=1/4 for the roughness, dynamical, and growth exponents, respectively, that describe the front behavior. This is similar to continuum limit analyses based on a perturbative stress-intensity treatment of the front [H. Gao and J. R. Rice, J. Appl. Mech. 56, 828 (1989)]. We discuss the differences to recent experiments.Peer reviewe

Consumer perception of food products involving genetic modification: Results from a qualitative study in four Nordic countries

1. The present study addresses consumer acceptance of food products involving the use of different applications of genetic modification in four Nordic countries. Three food products were used as examples: hard cheese, hard candy, and salmon. Three types of applications of genetic modification were investigated: modification of the raw material, use of genetic modification in enzyme production, and direct use of genetically modified microorganisms. In addition, three levels of presence of the genetically modified material in the final product were investigated: not present, present, and present and living/able to function. 2. The results from consumer samples in Denmark, Finland, Norway and Sweden are remarkably similar, showing a strong stability in consumer reactions to the use of genetic modification in food production in these four countries. 3. Consumer perception is characterised by a basic dichotomy of GM and non-GM products. Being non-GM is regarded as a major benefit in itself. When a product involves genetic modification, this elicits numerous negative assocations, of which the strongest ones are ‘unhealthy’ and ‘uncertainty.’ 4. The level of presence of the genetically modified material in the final product has a clear impact on consumer acceptance. When the GM material is present and viable/able to function, acceptance is lowest. 5. The type of application of genetic modification has an impact on consumer acceptance as well, but it differs across products. Still, there is a clear tendency that acceptance of salmon products where the salmon itself was genetically modified was lowest among all products tested. 6. The consumer benefits which the application of GM brings about (e.g., improved taste, functional benefits, environmental benefits) are largely perceived, but cannot overcompensate for the negative associations to GM. In some cases, a supposed benefit (e.g., faster growth of salmon, leading to reduced energy costs) was actually perceived as a disadvantage. Benefits combining personal tangible benefits with societal relevance (e.g., a low calorie candy which can be consumed by people suffering from diabetes) may have most positive impact on consumer acceptance.Consumer behaviour; Buying behaviour; Food; Denmark; Norway; Sweden; Finland

Kramers-Kronig, Bode, and the meaning of zero

The implications of causality, as captured by the Kramers-Kronig relations between the real and imaginary parts of a linear response function, are familiar parts of the physics curriculum. In 1937, Bode derived a similar relation between the magnitude (response gain) and phase. Although the Kramers-Kronig relations are an equality, Bode's relation is effectively an inequality. This perhaps-surprising difference is explained using elementary examples and ultimately traces back to delays in the flow of information within the system formed by the physical object and measurement apparatus.Comment: 8 pages; American Journal of Physics, to appea

Non-universality of elastic exponents in random bond-bending networks

We numerically investigate the rigidity percolation transition in two-dimensional flexible, random rod networks with freely rotating cross-links. Near the transition, networks are dominated by bending modes and the elastic modulii vanish with an exponent f=3.0\pm0.2, in contrast with central force percolation which shares the same geometric exponents. This indicates that universality for geometric quantities does not imply universality for elastic ones. The implications of this result for actin-fiber networks is discussed.Comment: 4 pages, 3 figures, minor clarifications and amendments. To appear in PRE Rap. Com

Elasticity of Poissonian fiber networks

An effective-medium model is introduced for the elasticity of two-dimensional random fiber networks. These networks are commonly used as basic models of heterogeneous fibrous structures such as paper. Using the exact Poissonian statistics to describe the microscopic geometry of the network, the tensile modulus can be expressed by a single-parameter function. This parameter depends on the network density and fiber dimensions, which relate the macroscopic modulus to the relative importance of axial and bending deformations of the fibers. The model agrees well with simulation results and experimental findings. We also discuss the possible generalizations of the model.Peer reviewe

Robust tuning of a generalized predictor-based controller for integrating and unstable systems with long time-delay

In this work, a general structure to control long time-delay plants is proposed and an easy methodology to tune the control parameters is outlined. All the sensitivity transfer functions are delay free. The proposed scheme is equivalent to the Smith predictor but able to cope with any kind of systems, including nonminimum phase, unstable and integrating plants. The controllers are designed based on the delay free model. Contrary to other approaches, other than for the digital implementation, no delay approximation is used. A tuning parameter is provided in order to reach an intuitive tradeoff between performance and robust stability. A comparative analysis with respect to recently successful proposals shows a substantial improvement in the performance/robustness tradeoff as well as in the tuning process.This work has been partially granted by the Spanish Ministry of Education research Grants DPI2011-28507-C02-01 and PAID-06-12. The authors are also grateful to the Associate Editor and anonymous reviewers for their valuable feedback and comments.García Gil, PJ.; Albertos Pérez, P. (2013). Robust tuning of a generalized predictor-based controller for integrating and unstable systems with long time-delay. Journal of Process Control. 23(8):1205-1216. https://doi.org/10.1016/j.jprocont.2013.07.008S1205121623