This year to celebrate Halloween, Digital Science have compiled their top five spooky scientific research papers.

Early life stress is a major risk factor for later episodes of depression. In fact, adults who are abused or neglected as children are almost twice as likely to experience depression. 

Scientific research into this link has revealed that the increased risk following such childhood adversity is associated with sensitization of the brain circuits involved with processing threat and driving the stress response. More recently, research has begun to demonstrate that in parallel to this stress sensitization, there may also be diminished processing of reward in the brain and associated reductions in a person's ability to experience positive emotions.

Quebec City, October 27, 2015--After more than a century of speculation, researchers have finally proved that American eels really do migrate to the Sargasso Sea to reproduce. A team supervised by Professor Julian Dodson of Université Laval and Martin Castonguay of Fisheries and Oceans Canada reports having established the migratory route of this species by tracking 28 eels fitted with satellite transmitters. One of these fish reached the northern boundary of the Sargasso Sea, the presumed reproduction site for the species, after a 2,400 km journey. Details are published in the latest edition of Nature Communications.

When people talk or sing, they often nod, tilt or bow their heads to reinforce verbal messages. But how effective are these head gestures at conveying emotions?

Very effective, according to researchers from McGill University in Montreal. Steven R. Livingstone and Caroline Palmer, from McGill's Department of Psychology, found that people were highly accurate at judging emotions based on head movements alone, even in the absence of sound or facial expressions.

At the end of the Pleistocene mammoths of Northern Eurasia used to experience chronic mineral hunger. As a result they became extinct due to geochemical stress arising on a background of deep abiotic changes in ecosystems. Most likely they were receiving not enough of essential chemical elements. This hypothesis was developed by TSU paleontologists and based on a large-scale, 15-years long research. Detailed information you can find in an article of Sergei Leshchinsky, Head of Laboratory of Mesozoic and Cenozoic continental ecosystems, TSU Faculty of Geology and Geography. This article was published in Archaeological and Anthropological Sciences.

Ann Arbor, MI, October 27, 2015 - On average, 80% of American adults watch 3.5 hours of television per day and multiple observational studies have demonstrated a link between TV viewing and poorer health. In this new study published in the December issue of the American Journal of Preventive Medicine, investigators reported an association between increasing hours of television viewing per day and increasing risk of death from most of the major causes of death in the United States.

Vaccinations are often about children, but anti-science beliefs are often not caused by having them, which reaffirms the contention that ant-vaccine sentiment falls along predictable cultural lines, and includes a raft of other positions, like denial of GMOs and sentiments against energy production.

When the largest modern-day plant-eaters, elephants, are in an area, they devastate the vegetation, like has happened in a South African nature reserve. So 15,000 years ago, when the herbivores like the Columbian mammoth, mastodons and giant ground sloths were even larger, more numerous and more widely distributed, and there were no dentists with high-powered rifles to take them down, how did the landscape survive? 

An analysis of deaths in the United States between 1969 and 2013 finds an overall decreasing trend in the age-standardized death rate for all causes combined and for heart disease, cancer, stroke, unintentional injuries, and diabetes, although the rate of decrease appears to have slowed for heart disease, stroke, and diabetes.

Recurrently, uninformed journalists re-discover the h-index and decide to create their own list of the "top scientists" in their country. The most zealous also draw some summary statistics from the list, and then venture to speculate wildly about it. Alas, it's a pattern I've seen a few times now.

The latest is an article which somebody posted on my Facebook column. It is uninteresting to see what conclusions are drawn from the graphs and lists published there, as the data are quite incomplete - in the h-index-ordered list of Italian researchers I do not appear, for one, but similarly do not dozens of top scientists who have even higher h-indices.