North Korea's announcement this week of plans to test a nuclear weapon is hardly surprising. The six-party talks to negotiate an end to its nuclear program are dead, and the North faces escalating financial and economic sanctions by the United States and its allies.

Experts have long debated the real motivations of the North in developing nuclear weapons. Some contend that the nuclear program, even the latest pronouncement, is simply a bargaining chip to gain security guarantees and economic aid. Others see a long determination to become a nuclear state.

The North Korean leaders may have begun the nuclear program as leverage. But the U.S. invasion of Iraq seems to have hardened their conviction that the only way to protect their nation and their regime is to join the nuclear club. The North Koreans want to become a Pakistan rather than an Iraq.

Still, officials in Pyongyang hesitated to cross the provocative line of visibly demonstrating their capability. Pressure is being mounted to get them to back down from their pledge. But for a variety of reasons, they apparently believe the timing for a test is now optimal.

First of all, they hope to blame the Bush administration for their decision. In the statement issued this week, the North Korean government argued that alleged American war plans justify a nuclear test, a position that reflects the views of the North Korean military.

Second, the North anticipates the test will be successful. Although a plutonium weapon is more complicated than a uranium bomb, it is quite likely that the North now has sufficient confidence in a Nagasaki-style primitive bomb. This success would be an object of pride for an otherwise failing state, and bolster its claim to the status of a world-class military power.

Third, the North Koreans see their potential enemies tied down and unable to respond effectively. The Bush administration is locked into a disastrous war in Iraq, and about to be weakened even more if the Republicans lose the upcoming midterm elections. In South Korea, the government of President Roh Moo Hyun is already a lame duck and politically paralyzed.

Fourth, Pyongyang may bet that China and South Korea, the two principal sources of trade and economic aid, would not join the United States and Japan in any real sanctions against the North. The July missile tests by North Korea provoked international uproar and led to a U.N. resolution. But the real impact has been minimal.

Finally, the North may calculate that testing will facilitate Japan's efforts to become a "normal'' nation with a broader military role in the region. That prospect could increase tensions in Northeast Asia, especially between Japan and China, and that, the North may believe, is not necessarily bad for it.

The United States, South Korea and China must act together to show that these calculations are misguided and that the North will pay a painful price if it goes ahead. Certainly this severely tests the troubled American alliance with South Korea and the emergent partnership with China. But Pyongyang's miscalculations also offer an opportunity to repair the strained alliance and create a new structure of security cooperation in Northeast Asia.

It is no secret that Seoul and Washington have been at odds over how to deal with North Korea. But the test announcement has already accelerated a shift in South Korean opinion. Rather than holding the United States responsible for the current impasse, most Koreans now see North Korea as the instigator of crisis.

South Korean officials understand that without reinforcing the alliance now, no policy toward the North can be effective. The United States and South Korea should urgently agree on common action plans -- including a shutdown of investment and economic assistance from the South to the North -- and make those consequences clear to Pyongyang.

The planned visits of newly installed Japanese Prime Minister Shinzo Abe to Beijing and Seoul next week offer a similar opening to turn threat into opportunity. Abe intends to repair tattered ties to those Asian neighbors. Now the three Northeast Asian powers can demonstrate that a nuclear test will not lead to increased tensions but to the complete isolation of the North.

The danger of escalating actions that could lead, again, to war on the Korean peninsula is grave. The North Koreans should be assured that the door to a diplomatic solution remains open to them. But they must also understand that by profoundly misreading this moment, the North Korean leadership now stands completely alone in Northeast Asia.

Reprinted by permission.

In late September, the federal Centers for Disease Control and Prevention announced new guidelines recommending that all Americans ages 13 to 64 be voluntarily screened for HIV infection. That's a significant change from the previous guidelines, which recommended testing only for high-risk individuals, such as injection drug users or those with multiple sex partners.

The new guidelines were influenced by a study published last year in the New England Journal of Medicine, led by Douglas K. Owens, a CHP/PCOR core faculty member and an investigator at the VA Palo Alto. Owens and his colleagues -- including CHP/PCOR researchers Gillian D. Sanders, Vandana Sundaram, Kristof Neukermans and Laura Lazzeroni -- found that expanding HIV screening would be a cost-effective way to increase life expectancy and decrease the transmission of HIV. Below, Owens discusses the research and the CDC's new screening guidelines.

Q. Why does this new policy matter, and whom will it help?

Owens: The policy is a profound change because it advises that all individuals ages 13 to 64 be screened for HIV. It matters because it will identify people who have HIV but don't know it. These people will benefit because they'll have access to life-prolonging drugs that they otherwise might not have received until very late in the course of HIV disease. The rest of the community will also benefit, through reduced transmission of HIV.

Q. How did your findings contribute to the CDC adopting the new guidelines?

Owens: First, we found that widespread screening provides a substantial health benefit to HIV-positive people who are identified through screening and receive anti-retroviral treatment earlier than they would have otherwise. Early treatment added about a year and a half of life expectancy for these people. Second, we found a substantial potential benefit to the community because of reduced transmission of HIV. Transmission is reduced because many people cut down on risky behaviors (such as having unprotected sex) when they're identified as having HIV, and because anti-retroviral treatment makes a person less infectious. Our key finding was that routine screening is cost-effective even if only 1 in 2,000 people who are screened have HIV. This means HIV screening is cost-effective in a much broader group than recognized previously.

Q. How and why did the CDC revise its previous guidelines? What role did you and your colleagues play in the decision-making?

Owens: CDC officials made this change because they saw mounting evidence that the prior approach to screening -- focusing on those with identifiable risk factors -- simply wasn't working. If you test people based on risk behavior, you miss many people who have HIV. Even among people who had easily identified risk behaviors, many of them weren't being tested. We also know that most people who have HIV are diagnosed very late in the disease, when they can't get the full benefit from anti-retroviral therapy.

Our involvement in the decision-making was to help assess the prevalence of HIV at which routine screening would be recommended. Through several conference calls with CDC officials, we presented our work and explained the issues related to cost-effectiveness and prevalence. Based on those results and the results of a similar study from Yale, the agency went in the direction of lowering the threshold for screening quite substantially -- to 1 in 1,000 from a prior threshold of 1 percent.

Q. Will most physicians follow the new guidelines? What can be done to make sure they do?

Owens: That's the big question. The CDC's previous screening guidelines were not widely adopted. The new recommendations are much easier to adopt, because they don't depend on clinicians determining the prevalence of HIV in their patient population. Still, it will take a lot of follow-up to make sure physicians implement the guidelines. One key obstacle will be getting payers to reimburse for HIV testing. That's a critical issue, which the CDC is well aware of.

Q. Some HIV/AIDS advocates object to the new guidelines because they recommend removing two requirements that some states now have: mandatory signed consent forms and counseling before testing. Does removing these requirements pose a big problem?

Owens: It's important to emphasize that the new guidelines say people should always be informed before testing and should be able to decline. Informed consent and pretest counseling had become significant barriers that were preventing people from being tested who should have been tested. Everyone agrees that no one should be tested without their knowledge, but that doesn't mean you need a separate consent form. Of course, the confidentiality of the test results should continue to be carefully protected. I would point out that some states have laws requiring informed consent, but whether they will now change those laws isn't clear.