OTA doubts value of demonstration projects Although demonstration projects have become something of the rage among federal agencies, "their effec­tiveness has been limited," according to a new report by Congress' Office of Technology Assessment. What makes this conclusion all the more signifi­cant, OTA says, is that the federal government annually spends more than $1 billion for demonstration programs, including both technolog­ical projects and social programs.

Demonstration projects are used by federal agencies to try out new tech­nology or social programs that agency administrators are unsure of. They also represent a compromise between project advocates, who see demon­strations as a way to "get a foot in the door" for more government funding, and project opponents, who view demonstrations as the next best thing to doing nothing at all. Yet "despite their obvious potential," OTA con­cludes, "demonstrations can easily be misused."

OTA cites an instance in which the technology to be demonstrated was not well in hand when the project was launched and it ultimately led to an

ironic and erroneous conclusion. In this case, OTA notes, revisions had to be made in a desalination plant in Texas to improve performance of the process used. The plant's perfor­mance was indeed improved by the new work, but it also interrupted plant operations. This caused po­tential users of the new technology to conclude that the desalination pro­cess was unreliable.

The OTA report warns that dem­onstration projects also can be used for strictly political ends and often are considered politically attractive by members of Congress. They can be used, OTA observes, as a form of "symbolic action"—a way to show the voters back home that the govern­ment in Washington is doing some­thing for them—particularly in emergency situations such as an en­ergy shortage.

As alternatives to demonstration projects funded by the government, OTA suggests a number of possibili­ties, one of which stands out: "When a demonstration is proposed to over­come government-created market imperfections, serious consideration should be given to altering those im­perfections as an alternative to large-scale involvement in demon­stration projects." •

Safety claims stir up saccharin cancer issue "Neither saccharin nor cyclamate is likely to be carcinogenic in man, at least at moderate dietary ingestion levels," reads the conclusion of an epidemiologic study conducted by Dr. Irving I. Kessler and J. Page Clark of Johns Hopkins University and pub­lished last week in the Journal of the American Medical Association. Al­though the study produced a ripple through the national news media, "it is neither new nor definitive," ac­cording to Dr. Robert N. Hoover of the National Cancer Institute.

"Data from the just-published study went into the general evalua­tion of saccharin studies conducted by the saccharin working group," Hoover explains. That group consists of an interagency task force drawn largely from NCI and the Food & Drug Administration. Last January, the group made available its prelim­inary findings and recommendations, which were based on a careful review of many of the published and un­published saccharin studies (C&EN, Jan. 30, page 7).

The saccharin working group con­cluded then that available evidence, including that from the Johns Hop­kins scientists, was insufficient to determine whether "artificial sweet­

eners, specifically saccharin, increase the risk of bladder cancer." Hence a major joint NCI-FDA study was launched, one that is national in scope and that will survey about 9000 peo­ple. Results from that study are not expected for another 12 to 14 months.

"There's a body of opinion that saccharin is a promoter of cancer, not an initiator," Hoover says. If so, sac­charin by itself might not cause can­cer, though it might boost effective­ness of other cancer-causing agents. That belief, taken along with the small numbers of patients studied so far, "prompted people to think that a very large study was needed to see if there were other risk factors," he adds.

The just-published study, by con­trast, was on a modest scale, involving 519 bladder cancer patients and 519 "cancer-free patients" as controls. There are several problems with this study, Hoover says. First, Kessler and Clark omitted (by necessity) from their survey 509 bladder cancer pa­tients who died. "A major concern" is that there might have been high ar­tificial sweetener use among those patients who died from "particularly aggressive" cancers. Second, both

controls and cancer survivors were patients in hospitals. Thus the con­trols might include many, for exam­ple, who were overweight, biasing the sample. Finally, the relatively small number of patients studied might not be enough to detect a small increase in risk from consuming artificial sweeteners. •

Spacecraft to probe Venus atmosphere Pioneer Venus II, the first U.S. at­tempt to send instruments into the atmosphere of Venus, is scheduled for launch from Cape Canaveral, Fla., next Monday. The spacecraft also is called the Venus Multiprobe: 24 days before its arrival at the planet on Dec. 9, it will split into five separate in­strument packages that will plunge into Venus' dense, cloudy atmosphere at widely spaced points in both the day and night hemispheres.

A companion spacecraft, Pioneer Venus I, was launched May 20 and will arrive there Dec. 4. It is designed to orbit the planet for a year or more, making remote measurements of the atmosphere, photographing cloud circulation, and mapping the Venu-sian surface by radar. It will be the first prolonged orbiter of Venus.

Together, the orbiter and the multiprobe may shed new light on one of the most puzzling questions of planetary science: Why do earth and Venus, each endowed with about the same mass, probably formed out of similar materials and situated at comparable distances from the sun, have atmospheres so completely dif­ferent?

The Venusian atmosphere is im-

Pioneer Venus satellite being prepared for its long journey to Venus

July 31, 1978 C&EN 5