How Grandparents Matter: Support for the Cooperative Breeding Hypothesis in a Contemporary Dutch Population

Low birth rates in developed societies reflect women’s difficulties in combining work and motherhood. While demographic research has focused on the role of formal childcare in easing this dilemma, evolutionary theory points to the importance of kin. The cooperative breeding hypothesis states that the wider kin group has facilitated women’s reproduction during our evolutionary history. This mechanism has been demonstrated in pre-industrial societies, but there is no direct evidence of beneficial effects of kin’s support on parents’ reproduction in modern societies. Using three-generation longitudinal data anchored in a sample of grandparents aged 55 and over in 1992 in the Netherlands, we show that childcare support from grandparents increases the probability that parents have additional children in the next 8 to 10 years. Grandparental childcare provided to a nephew or niece of childless children did not significantly increase the probability that those children started a family. These results suggest that childcare support by grandparents can enhance their children’s reproductive success in modern societies and is an important factor in people’s fertility decisions, along with the availability of formal childcare

Introducing the fit-criteria assessment plot – A visualisation tool to assist class enumeration in group-based trajectory modelling

Background and objective Group-based trajectory modelling is a model-based clustering technique applied for the identification of latent patterns of temporal changes. Despite its manifold applications in clinical and health sciences, potential problems of the model selection procedure are often overlooked. The choice of the number of latent trajectories (class-enumeration), for instance, is to a large degree based on statistical criteria that are not fail-safe. Moreover, the process as a whole is not transparent. To facilitate class enumeration, we introduce a graphical summary display of several fit and model adequacy criteria, the fit-criteria assessment plot. Methods An R-code that accepts universal data input is presented. The programme condenses relevant group-based trajectory modelling output information of model fit indices in automated graphical displays. Examples based on real and simulated data are provided to illustrate, assess and validate fit-criteria assessment plot's utility. Results Fit-criteria assessment plot provides an overview of fit criteria on a single page, placing users in an informed position to make a decision. Fit-criteria assessment plot does not automatically select the most appropriate model but eases the model assessment procedure. Conclusions Fit-criteria assessment plot is an exploratory, visualisation tool that can be employed to assist decisions in the initial and decisive phase of group-based trajectory modelling analysis. Considering group-based trajectory modelling's widespread resonance in medical and epidemiological sciences, a more comprehensive, easily interpretable and transparent display of the iterative process of class enumeration may foster group-based trajectory modelling's adequate use

Natural Organic Matter Removal by Heterogeneous Catalytic Wet Peroxide Oxidation (CWPO)

NOM usually reaches drinking water supply sources through metabolic reactions and soil leaching. It has been, in general, considered that NOM is still one of the most problematic contaminants present in this kind of influents. Therefore, in the present chapter, most relevant technologies used for removal of NOM and its constituents from water have been examined, emphasizing in the past few years. An overview of the recent research studies dealing the NOM removal by catalytic wet peroxide oxidation and other closely related heterogeneous Fenton-like AOPs is presented. As revealed from recent literature reports, heterogeneous Fenton processes including CWPO are still emerging, promising catalytic technologies for NOM removal from water. A wide variety of catalytic solids reported within the past few years has been examined focusing on their potential in the NOM removal from water. Main findings offered by several types of catalysts like zeolites, Fe-functionalized activated carbons, carbon nanotubes, but mainly pillared and other clay minerals have been critically discussed emphasizing on the NOM removal by CWPO