Competing gravity of galactic clouds probably caused band of gas
A gravitational tug-of-war between the Large Magellanic Cloud and the Small Magellanic Cloud may be responsible for the huge ribbon of gas at the halo of the Milky Way. Astronomers in the U.S. and Germany measured how much oxygen and sulphur there is in the Magellanic Stream by looking at how they absorbed ultraviolet light coming from distant galaxies to form their conclusion that the ribbon of gas probably comes from both galaxies
Fox, A. J. et al (2013) The COS/UVES Absorption Survey of the Magellanic Stream: I. One-Tenth Solar Abundances along the Body of the Stream arXiv 1304.4240
Richter, P. et al. (2013) The COS/UVES Absorption Survey of the Magellanic Stream: II. Evidence for a complex enrichment history of the Stream from the Fairall 9 sightline arXiv1304.4242
Macrophages let salamanders replace limbs
Salamanders can regrow limbs thanks to their immune systems, which could also play a role in the regeneration of their spinal cords, brain tissue, and even parts of their hearts.
Godwin et al (2013) Macrophages are required for adult salamander limb regeneration PNAS DOI: 10.1073/pnas.1300290110
Researchers grow human thymus tissue using stem cells
Researchers grew functioning human thymus tissue using stem cells and growth factors. Thymus tissue plays an important role in the immune system by fostering the growth of T cells. The technique has potential applications in the transplantation of stem cells, tissue and organs.
Parent et al (2013) Generation of Functional Thymic Epithelium from Human Embryonic Stem Cells that Supports Host T Cell Development Cell Stem Cell DOI: 10.1016/j.stem.2013.04.004
Breeding patterns may explain why most snails coil to the right
Researchers have found that the vast majority of snails coil to the right. Only 5% of the more than 55,000 snail species studied were found to be sinistral, or left-coiling. Scientists say breeding practices among many snails prevent them from mating with sinistral snails, which could lead to their extinction.