By John Timmer, Ars Technica

We tend to get overly focused on bacteria that are trying to kill us (and there’s no shortage of those), but there are large populations of bacteria that live in or on us without causing any problems, and some of them are even helpful. This is especially true in the gut, where bacteria help us with the food we eat and provide some essential nutrients; there’s even evidence that our gut bacteria can influence our behavior. This creates a bit of a challenge for the immune system, which needs to kill harmful bacteria and avoid killing helpful ones—but still k...

With the launch of iOS 5 on Wednesday and the iPhone 4S today, excited iOS users have queued up to make the transition to Apple’s latest and greatest. Unfortunately for many, the transition hasn’t been as smooth as they’d hoped.

A number of early adopters who tried to upgrade to iOS 5 late Wednesday and Thursday experienced errors due to a massive influx of traffic on Apple’s servers. And this morning, Verizon and AT&T’s activation servers appear to be having a similar issue. Luckily, repeated attempts, or just waiting a while until server loads go down, fixes the issue for most upgraders.

M...