It isn't just human adults who regard youth as disease factories, in many species the young are often more susceptible to infection than adults, even after accounting for prior exposure to infection.

Evolution has an explanation for that. But like a lot of things in evolution, it may seem puzzling.

It shouldn't make sense, since dying young or becoming infertile due to infection means organisms will be unable to reproduce, but many species may have evolved to prioritize growth over immunity while maturing. And that complexity may be why immunity varies with age in different species.

A new study shows that smokers who switch to nicotine vapor alternatives (e.g. e-cigarettes or iQOS) may be better able to stay smoke-free in the long term - even if they didn't set out to quit smoking. 

And that even people who didn't want to stop smoking have eventually quit because they found vaping more enjoyable.  E-cigarettes contain nicotine, which is the addictive component of cigarettes also, but it's toxic chemicals in smoke that cause the harms of smoking. That is why e-cigarettes have caught on as an aid to help people quit smoking for good, whereas patches and gums are only effective for about 10 percent. 

If you want to map opioid prescription use, you can do it, right down to Congressional district. The highest rates are in the southeastern U.S., Appalachia and the rural west, all areas where there is more manual labor, according to an analysis in American Journal of Public Health.

The authors believe this could help policy makers at the federal and state level better target intervention and prevention strategies, though statistics have shown prescription use is not the problem, illegal recreational use is.

Over 25 years ago, members of Congress saw statistics showing that U.S. people with college educations made more money, and they declared that college education should be a right. The solution was indicative of government - change student loans to being unlimited.

Are young people all making more money? No, they are buried in debt, but schools that were once foundering are now doing quite well. An entirely industry built up around universities for under-achieving students with money. And on the other end, credentialism came into play. A bachelor's degree became what a high school diploma was. 

Neuroscientists believe that people's earliest memories date from around three to three-and-a-half years of age but many people report memories much earlier than that. It's likely just as fake as claims of repressed memories from the 1980s. 

At least according to surveys, which are just as unreliable as science claims about memory. 

Survey results of people's first memories found that 38.6 percent of 6,641 people claimed to have memories from two or younger, with 893 people claiming memories from one or younger. This was particularly prevalent among middle-aged and older adults.

Social media is king. It can run pizza chain founders out of their companies, it can be used by anti-science activists to mobilize well-meaning science advocates against other science advocates, but what it can't do is change human nature. And human nature says people will visit those nearby.

Even when people have well-connected social networks state lines, they are still most frequently interacting with people who are geographically close. Except in Los Angeles. Apparently everyone is looking for a reason to leave Los Angeles.