considerable progress has been achieved. The Ad hoe Group of Scientific Experts has, through close international co-operation, developed a global seismic verification system. A modern design of this system is now being tested. The experiment is proceeding successfully, but there is a need for increased participation in the test in order to achieve a more global distribution of seismic stations. In fact, many countries have technical facilities making it possible for them to participate in this global experiment. It is important that more States should take the necessary political decision allowing for broader participation. This would effectively contribute to the development of a global seismic verification system. CD/PV.550 8 (Mr, Hyltenius, Sweden) Among other verification measures for a comprehensive test-ban treaty, the monitoring of atmospheric radioactivity may be mentioned. It has on a number of occasions been discussed in the Conference on Disarmament, and Sweden has proposed that a global system should be established for this purpose. On-site and in-country monitoring stations, as well as satellite-based surveillance systems, can also play an important part in verifying a comprehensive test-ban treaty. On the basis of an extended mandate, the Ad hoe Group of Scientific Experts should start deliberations on these verification techniques too, drawing on the experience developed over a long period of time in this Group. After this plenary meeting the Conference will have occasion to deliberate in an informal plenary meeting on agenda item 2, "Cessation of the nuclear arms race and nuclear disarmament". The convening of informal plenary meetings is the result of successful consultations carried out by Ambassador Azikiwe of Nigeria as President of the Conference during the month of March. Item 3 on our agenda "Prevention of nuclear war, including all related matters", will be subject to consideration in the same format later 
**Analysis**
The text discusses the development of a global seismic verification system, monitoring of atmospheric radioactivity, and the consideration of on-site and satellite-based surveillance systems. This suggests that the text is related to scientific and technological advancements, specifically in the field of nuclear disarmament and arms control.

**Category**
Science and technology