Among many mammals, lactating females may have extended periods of time in between nursing bouts. This is often the case for females who “cache” or “park” their young in nests, dens, or burrows while they depart to forage more efficiently unencumbered by the presence of the young (parents, you know what I am talking about). The egg-laying echidna is an excellent, if totally weird, example. Afte...

The article (1) by Gancedo and Strain in PNAS studies how singularities may develop in the initially smooth interfaces separating two or more incompressible fluids. The fluids and interfaces are assumed to evolve by either of the two standard systems of equations from fluid mechanics, namely the surface quasi-geostrophic (SQG) sharp front equation (2) or the Muskat equation (3). Gancedo and Str...

undreds of microRNAs are encoded in animal genomes, yet the function of only two were known until recently. That number has now doubled with the identification of two miRNAs, mir14 and bantam , both of which appear to regulate cell death in Drosophila , according to reports from Peizhang Xu, Bruce Hay (California Institute of Technology, Pasadena, CA), and colleagues and from Julius Brennecke, ...

An original simplified finite element model is proposed to simulate the effects of non-penetrating ballistic impacts causing so-called bullet splash phenomenon (complete fragmentation), while no fragmentation caused target. The based on Arbitrary Lagrangian Eulerian formulation (ALE) and it simulates impact as a fluid-structure interaction. has been tested by experimental analyses AISI 304L pla...