Modeling nitrous oxide emission from full-scale hybrid membrane aerated biofilm reactors (MABR).

Current published models for nitrous oxide (NO) emission in membrane aerated biofilm reactors (MABR) have several simplifications that are not representative of full-scale systems. This study developed an improved MABR NO model that captured commonly overlooked phenomena such as back diffusion of generated NO into MABR lumen gas and the recirculation of the NO laden lumen gas for tank mixing and biofilm thickness control. The improved model was validated with measured NO concentrations in the lumen gas phase and bulk mixed liquor in a full-scale hybrid MABR facility.

Synchrotron X-ray Fluorescence Microscopy Reveals Trace Elemental Indicators of Life History in Marsupial Teeth.

As teeth develop, their mineralised composition is a bio-recorder of diet, environment, and growth. High-resolution elemental mapping provides a tool to reveal records of life history within teeth. The relative concentrations of a range of trace elements change between in utero development, birth, and weaning in eutherian mammals.

Functional optimality underpins the repeated evolution of the extreme "saber-tooth" morphology.

"Saber teeth"-elongate, blade-like canines-are a classic example of convergence, having evolved repeatedly throughout mammalian history. Within canine teeth, there is a trade-off between the aspects of shape that improve food fracture and those that increase tooth strength. Optimal morphologies strike a balance between these antagonistic functional criteria.