Preliminary research published this week in JAMA indicates that decreased levels of serotonin  and tryptophan hydroxylase in the brainstem are associated with an increased risk for sudden infant death syndrome (SIDS).

 The study included for biochemical analysis 35 infants dying from SIDS, 5 infants with acute death from known causes (controls), and 5 hospitalized infants with chronic hypoxia-ischemia (a reduction in oxygen supply combined with reduced blood flow to the brain). Tissue samples were obtained via autopsy and levels of serotonin and several enzymes, including serotonin (5-HT) and tryptophan hydroxylase (TPH2), were measured and analyzed.

A 60-million-year-old relative of crocodiles named Cerrejonisuchus improcerus ("small crocodile from Cerrejon") was likely a food source for Titanoboa, the largest snake the world has ever known, says a new study published this week in the Journal Vertebrate Paleontology.

Researchers from Smithsonian Tropical Research Institute in Panama and paleontologists from the Florida Museum of Natural History found fossils of the new species of ancient crocodile in the Cerrejon Formation in northern Colombia. The site, one of the world's largest open-pit coal mines, also yielded skeletons of the giant, boa constrictor-like Titanoboa, which measured up to 45 feet long. The study is the first report of a fossil crocodyliform from the same site.

By considering molecular-level events on a broader scale, researchers now have a clearer and more complicated picture of how one class of immune cells goes wrong when loaded with cholesterol. The findings reported in Cell Metabolism show that, when it comes to the development of atherosclerosis and heart disease, it's not about any one bad actor—it's about a network gone awry.

The new findings also highlight a pretty remarkable thing: researchers still aren't sure how cholesterol causes heart disease.