although I think it's fair to say that not all retractions are the result of fraud. I'm not sure about the ins and outs of this case for example http://retractionwatch.com/2014/12/26/nature-cell-biology-in... but I think it looks like a straightforward revision due to more up to date information. This seems to be a good example of how science should work i.e. scientists posit theory, scientists receive new information and update or revise theory in light of this.