Challenging the challenge hypothesis on testosterone in fathers: Limited meta-analytic support

In fathers testosterone levels are suggested to decrease in the context of caregiving, but results seem inconsistent. In a meta-analysis including 50 study outcomes with N = 7,080 male participants we distinguished three domains of research, relating testosterone levels to parental status (Hedges’ g = 0.22, 95% CI: 0.09 to 0.35; N = 4,150), parenting quality (Hedges’ g = 0.14, 95% CI: 0.03 to 0.24; N = 2,164), and reactivity after exposure to child stimuli (Hedges’ g = 0.19, 95% CI: -0.03 to 0.42; N = 766). The sets of study outcomes on reactivity and on parenting quality were both homogeneous. Parental status and (higher) parenting quality were related to lower levels of testosterone, but according to conventional criteria combined effect sizes were small. Moderators did not significantly modify combined effect sizes. Results suggest that publication bias might have inflated the meta-analytic results, and the large effects of pioneering but small and underpowered studies in the domains of males’ parental status and parenting quality have not been consistently replicated. Large studies with sufficient statistical power to detect small testosterone effects and, in particular, the moderating effects of the interplay with other endocrine systems and with contextual determinants are required

Effects of vasopressin on neural processing of infant crying in expectant fathers

Multivariate analysis of psychological dat

The Coevolution of Phycobilisomes: Molecular Structure Adapting to Functional Evolution

Phycobilisome is the major light-harvesting complex in cyanobacteria and red alga. It consists of phycobiliproteins and their associated linker peptides which play key role in absorption and unidirectional transfer of light energy and the stability of the whole complex system, respectively. Former researches on the evolution among PBPs and linker peptides had mainly focused on the phylogenetic analysis and selective evolution. Coevolution is the change that the conformation of one residue is interrupted by mutation and a compensatory change selected for in its interacting partner. Here, coevolutionary analysis of allophycocyanin, phycocyanin, and phycoerythrin and covariation analysis of linker peptides were performed. Coevolution analyses reveal that these sites are significantly correlated, showing strong evidence of the functional and structural importance of interactions among these residues. According to interprotein coevolution analysis, less interaction was found between PBPs and linker peptides. Our results also revealed the correlations between the coevolution and adaptive selection in PBS were not directly related, but probably demonstrated by the sites coupled under physical-chemical interactions

Can Mobile Phone Data Improve Emergency Response to Natural Disasters?

Peter Gething and Andrew Tatem discuss the potential impact of mobile phone positioning data on disaster response and highlight challenges that must be addressed if use of this technology is to develop

Modelling wave damping by fluid mud: Derivation of a dispersion equation and an energy dissipation term and implementation into SWAN

On numerous locations in the world mud occurs in front of the coast close to river mouths. This mud can be transported to these places in fluid state or can become fluid under certain wave conditions. Fluid mud may have a strong damping effect on surface waves. Dissipation of up to 90% of the wave energy within a few kilometers has been measured. In this study, the wave model SWAN is modified to make it possible to model the dissipation of energy during the propagation of a wave field over fluid mud. A two-layer model is used to describe the water-mud-system. The upper layer represents the water and is non-hydrostatic and non-viscous. The lower layer represents the fluid mud and is quasi-hydrostatic and viscous. Based on this schematization a complex dispersion equation is derived and compared with other dispersion equations from literature. A numerical solving procedure is formulated to solve this implicit complex dispersion equation for the wave number. When the wave number is known, information on the damping is given by the imaginary part, while the real part is associated with the wave length and the propagation velocity of energy. To compute wave damping for situations in practice, the influence of mud is incorporated in the wave model SWAN. First, the energy dissipation term consistent with the dispersion equation is derived and added as a sink term to the energy balance in SWAN. By making the mud-adjusted wave number available through the whole code, also influence of fluid mud on energy propagation is included in the model. The performance of the model for both energy dissipation and energy propagation is validated and compared to analytical solutions for some simple cases. Result The final result of this study is a modified version of SWAN which allows to model the decrease of energy during the propagation of a wave field over fluid mud. The model is ready for use in engineering applications by specialists.Civil Engineering and Geoscience

Two-phase modeling of sheet-flow beneath waves and its dependence on grain size and streaming

We study erosion depth and sediment fluxes for wave-induced sheet-flow, and their dependency on grain size and streaming. Hereto, we adopt a continuous two-phase model, applied before to simulate sheet-flow of medium and coarse sized sand. To make the model applicable to a wider range of sizes including fine sand, it appears necessary to adapt the turbulence closure of the model. With an adapted formulation for grain–carrier flow turbulence interaction, good reproductions of measured erosion depth of fine, medium and coarse sized sand beds are obtained. Also concentration and velocity profiles at various phases of the wave are reproduced well by the model. Comparison of sediment flux profiles from simulations for horizontally uniform oscillatory flow as in flow tunnels and for horizontally non-uniform flow as under free surface waves, shows that especially for fine sand onshore fluxes inside the sheet-flow layer increase under influence of progressive wave effects. This includes both the current-related and the wave-related contribution to the period-averaged sheet-flow sediment flux. The simulation results are consistent with trends for fine and medium sized sediment flux profiles observed from tunnel and flume experiments. This study shows that the present two-phase model is a valuable instrument for further study and parameterization of sheet-flow layer processes