 They, in some respects of dimensions, keep changing. There are spectacular successes and challenges that still remain. For example, with PEPFAR, the story I told you of PEPFAR, it was how we can get therapy to people who need it. So if you look globally, particularly in the developing world, that by the standard criteria of who should be receiving and therefore would benefit greatly from therapy, only about 30% of the adults in the low and middle income countries who would clearly benefit from therapy have access to therapy and less than 10% of the children in the developing world who would have benefit from therapy have access to therapy. So we have something that's a global health issue, a biomedical research and science issue and a broad societal issue. So one is access to therapy. The other is something that's very sobering. For every one person that we put on therapy globally, two to three people get newly infected. And since therapy is a lifelong issue, because if you stop therapy, the virus comes back. If you do the numbers, it's a non-sustainable situation. So we have an enormous challenge with the prevention of HIV, not only internationally and globally in the developing world, but we even have it here in the United States where 56,300 people get newly infected each year, mostly in the African American community. So there are many, many challenges. So what I said at the Ideas Festival is that the theme was much accomplished, much to do. We've accomplished breathtaking things with regard particularly to therapy for those who have access to therapy. The other issue is prevention. The last holy grail scientifically of that is the development of a vaccine, which has been very difficult for a variety of complicated reasons, but it's also access for people who don't have access. And the thing is, if you go to Africa, if you go to Asia, the cultural and societal issues that are stumbling blocks on the way to a successful approach to HIV relates to everything from the disenfranchisement of women in certain societies. Women don't have the same rights as men for sure. Poverty breeds the kind of sexual, commercial transactional sex that gets young women who are poor to be the sexual partners of men who don't want to use condoms, who infect young women, they go back to their village, they get married, they infect their husband or whatever. It becomes a very difficult situation that's going to require leadership from the top in certain nations where the fundamental societal, cultural, traditional way of interacting sexually between men and women provides a fertile ground for a sexually transmitted disease. It's very difficult, for example, for a white guy with a suit like me to go in and say, what you should be really doing is this, you've got to get the leadership of the country to understand that they're dealing with what might be a potential and an already public health catastrophe in their country. Some countries get it and are really doing something about it, such as Uganda with President Museveni and others, are really providing the kinds of leadership. In other countries, it's not the case, unfortunately. So that's what I spoke about in Aspen when I said about the challenges of what we need to do by the year 2015-2025.