Clearinghouse Update
From time to time we update our readers on situations which have been described in our Newsletter. In our last issue we updated our longstanding coverage of PCBs (PolyChlorinated Biphenyls) in the Hudson River by citing the extension of an 18-month cleanup delay to more than seven years. According to the 25 February 1998 issue of The New York Times, this cleanup delay will continue several more years while a report originally due this year is delayed to allow further outside scientific and public review. The latest action has Congressional Representatives of various districts along the Hudson River pitted into opposing camps. Meanwhile, on 24 April 1998, National Public Radio's "Morning Edition" reported that the Environmental Protection Agency (EPA) is taking a more aggressive attitude toward cleanup of PCBs in the neighboring Housatonic River in northwestern Masachusetts. Like the PCBs in the Hudson River, those in the Housatonic were also caused by General Electric. To clean up the Housatonic, EPA is setting up a Superfund site, to accomplish the cleanup now and deal with the details of how much General Electric will pay later.
More on HDTV
Our Spring 1997 issue related the story of the development of High Definition TeleVision (HDTV). As part of the Princeton Plasma Physics Laboratory "Science on Saturday" series, a demonstration of HDTV was presented at the Sarnoff Corporation on 14 February 1998, and Norman Hurst and Michael Isnardi of the Sarnoff staff lectured on "TV Systems Old and New: Introducing Digital, High Definition Television."
In describing the development of television through the present, Hurst observed that each channel occupied a bandwidth of 6 MHz, a little less than a third of the bandwidth of all 100 FM radio stations. With approximately twice as many lines from top to bottom and more than twice as many dots across (because the screen is wider, due to a larger aspect ratio), HDTV will need to transmit five times the information of the present SDTV (Standard Definition TeleVision).
How to transmit this increased amount of information within the same 6 MHz bandwith is one of the challenges HDTV has had to meet, and the answer is to compress the signal by eliminating redundancy arising from unchanging parts of the video signal or predictable motion. The video signal, originally requiring 1 Gbps (gigabyte per second), is to be compressed by a 50:1 ratio, and the 4.6 Mbps (megabyte per second) audio signal is to be compressed by a 12:1 ratio, so that the transmitted signal is limited to 20 Mbps. Isnardi likened this compression to compressing freshly-squeezed orange juice into concentrate, which reduces the amount to be transported to stores just as compression of the HDTV signal reduces the information it carries.
Because HDTV represents a changeover from analog to digital transmission as well a higher resolution of the video signal, Isnardi also likened the changeover to HDTV to that from the phonograph record to compact disc. Its digital nature also eliminates inteference between adjacent channels which plagues the present analog transmission system of SDTV and has made certain channels "taboo" in certain markets. In addition to the enhanced video signal, it will also provide enhanced audio, with six channels: left, center, right, left surround, right surround, and low frequency effects. Its larger aspect ratio -- 16:9 (not the 5:3 reported in our Spring 1997 story) -- follows the lead of wider screen movies, although Isnardi mused that the present 4:3 aspect ratio derived from following Edison's original aspect ratio for movies.
The first HDTV sets will be on the market by Christmas 1998 and the top four networks are to be transmitting HDTV signals by 1999, Isnardi said. Although the initial cost will be high -- $5000 to $10000 -- prices can be expected to decline in time much as they have for compact disc players. Those wishing to receive HDTV on their present analog sets can do so by purchasing a converter priced in the hundreds of dollars, although present analog telecasting will continue through 2006. Although HDTV pictures received on a present analog TV set will not have enhanced resolution, Isnardi said, they will be free of ghosts, "sparkles" from running the vacuum cleaner, and interference from adjacent channels. In fact, such conversion of digital signals for analog sets has been occurring since 1994 for the million subscribers to the Hughes or USSB digital satellite serivces, whose SDTV reception uses 4 Mbps signals for each channel.
Because the SDTV reception with present digital satellite services requires only 4 Mbps, the 20 Mbps HDTV channels can be used to carry multiple SDTV programs instead of one in HDTV format. In fact, Isnardi listed several HDTV and SDTV format which might be used: 1920 dots (wide) x 1080 lines (tall) or 1280 x 720 (HDTV), and 704 x 480 (16:9 aspect ratio) or 640 x 480 (4:3 aspect ratio) -- all at frame frequencies ranging from 24 per second (for movies) to 60 per second, and using "interlaced" or "progressive" scanning. When a channel is carrying multiple programs in SDTV, the viewer will select the channel using the "up" or "down" buttons on the remote control unit, then select the program within a channel using "left" or "right" buttons.
A New Approach to Producing Neutrons
The last Infusion Tip in our Winter 1996 issue cited an accelerator which could double as a source of tritium for nuclear weapons and a substitute for the Advanced Neutron Source canceled in 1995. While the new means of producing tritium are yet to be decided, the 23 January 1998 issue of Science reported that the neutron community is happy about building a $1.3 billion dollar Spallation Neutron Source at Oak Ridge National Laboratory but with input also from four other national laboratories: Lawrence Berkeley, Los Alamos, Argonne, and Brookhaven.
Randi Scooped by 11-year old on Therapeutic Touch
In her coverage of a talk by James Randi in our Spring 1997 issue, Irma Jarcho cited his challenge to the technique known as therapeutic touch. The 1 April 1998 issue of The New York Times reported Randi's difficulty in attracting therapeutic touch practitioners to "pass a test in detecting a human energy field." The same article reported the success of an eleven-year old student named Emily Rosa in getting 21 therapeutic touch practitioners to participate in a simpler test as part of her science fair project. As reported in an article co-authored by Emily in the 1 April 1998 issue of the Journal of the American Medical Association, the therapeutic touch practitioners correctly detected Emily's hand behind a screen in only 44 percent of 280 tests.
More Progress toward Lyme Vaccine
Irma Jarcho's report in our last issue of the Harvard School of Public Health presentation on Lyme disease mentioned the attempt to develop a vaccine against the disease. At least two pharmaceutical companies, Smith Kline Beecham and Pasteur Merrieux Connaught, have developed vaccines; and on 26 May a Food and Drug Administration panel recommended approving the Smith Kline Beecham vaccine for people between 18 and 70, provided that tests continue.
Another promising approach to treating Lyme disease is suggested by a report in the 19 April 1998 issue of The New York Times that the rarity of the disease in the American Far West results from a substance in the blood of the Western fence lizard which is fatal to the disease-causing spirochete. This lizard is a common host for the Western black-legged tick, which is a common transmitter of the disease in the West (as are white-footed mice or deer hosts for Lyme disease-transmitting ticks in the Northeast), and the spirochete is killed upon feeding on the lizard's blood. The lizard-blood substance has been isolated, but its nature is not yet known. If it is identified and proven safe, it can perhaps provide an answer to controlling Lyme disease in the Northeast.
Edison Schools Show Exam Gains
Since the first encouragement reported in our Fall 1996 "Update," the Edison Project reports more good news. According to the 17 December 1997 issue of The New York Times (p. B8), students in Edison schools have shown measurable gains in reading and math compared with their scores on earlier tests and those from students with similar backgrounds in other schools in the same district. However, the 8 May 1998 New York Times cited a 91-page report from the American Federation of Teachers which "questioned the more optimistic findings" of the December report.
Additional Concern about a Fixed Nitrogen Surplus
In her Winter 1998 "Observations" column, Irma Jarcho pointed to concern about excessive fixed nitrogen in the environment. Alexander Hellemans' article, "Global Nitrogen Overload Problem Grows Critical," in the 13 February 1998 issue of Science, points out that fixed nitrogen is now overwhelming all kinds of ecosystems to the point that the land is now unable to absorb or break down the increasing amounts. In aquatic environments, this has touched off brown and red algal blooms, which have impaired fisheries. On land, nitrogen compounds are displacing valuable nutrients in forest soils, with deleterious results.
Hellemans observes that until the turn of the century almost all fixed nitrogen came from nature. But the widespread use of synthetic fertilizers coupled with the increased nitrogen oxides from the burning of fossil fuels, especially in automobiles, shifted the balance. In addition to the eutrophication attributable to excess nitrogen in rivers, the ocean has created "dead zones." One such, now the size of the state of New Jersey, is expanding westward from the coast of Louisiana into Texas waters. These changes impair biological diversity and bode ill for the future.
Updated Perspective on Chico Mendes and Brazilian Rubber Tappers
Bill Day and Terry Schwartz, otherwise known as the Camera Guys, have produced Rubber Jungle, a 90-minute video which elaborates on the role of Francisco "Chico" Mendes among Brazilian rubber tappers, first mentioned in our Winter 1989 issue after Mendes' assassination. The Camera Guys were guided on their quest by Caito Martins, a Brazilian who first called them to Costa Rica to make a behind-the-scenes film about a movie that was never made there about Mendes. In Rubber Jungle Martins insists that this is because the real story is that of the Brazilian rubber tappers, which Day and Schwartz learn about by accompanying Martins up the Amazon River and eventually interviewing Mendes' widow in Xapuri.
Rubber Jungle picks up the story at a time when Brazil had a monopoly on the world rubber industry, from which Brazilian rubber barons benefited, at the expense of both Brazilian rubber tappers and those who paid high prices for Brazilian rubber, until Henry Wickham heisted Brazilian rubber tree seeds to establish a competing rubber industry in what was then Malaya. Later, to break British rubber monopolies, Henry Ford sought unsuccessfully to build his own Brazilian rubber plantations -- he planted rubber trees so closely that they were susceptible to disease. Even attempts to use disease-resistant Asian rubber trees failed.
Interest in Brazilian rubber was renewed after Japan denied access to Asian rubber in World War II, and Brazilian rubber tappers gathering rubber for the US were continually threatened by German U-boats plying the Amazon. After World War II, Brazilian rubber tappers were once again left impoverished, while Brazilian generals fighting the Cold War saw the jungle as a hideout for leftists and encouraged resource exploitation. Amazon ranchers hired pistoleros to evict rubber tappers.
In the 1980s Mendes became a rubber tapper union leader and achieved success through nonviolence against clearing rubber trees from the land. In 1986, though, Mendes went back on his agreeements with the ranchers and also split from the church, thus breaking two vital local linkages. The interview with Mendes' widow, Ilsemar, suggests that this change was brought about by external intervention which led to a partnership with the Environmental Defense Fund and brought Mendes international fame as a protector of Brazil's environment. Day and Schwartz sense that this helped international ecology but hurt Chico at home. Ilsemar herself became embroiled in court battles with her husband's former colleagues over control of the Chico Mendes Foundation, funded by income from the producer of the movie that was never made, and this left her reputation tarnished.
This is a sad story of the continuing plight of Brazilian rubber tappers as well as difficulties faced in trying to save Brazilian rainforest, made all the more difficult by the ascendance of synthetic rubber, but Day and Schwartz tell it engagingly. To obtain their Rubber Jungle, contact them at 1800 Stanford St., Santa Monica, CA 90404, (310)-264-2681, FAX: (310)-264-2683,
. More on Informing New Mothers of HIV Tests
In our Winter 1996 issue we reported that the battle to make known to mothers the results of HIV tests on their newborns had been resolved by requiring doctors to advise new mothers of the availability of these results. But now The New York Times of 14 May 1998 reports the dissatisfaction of doctors with the delays in getting the results of these tests. Some are reported more than a month late, losing precious time for the treatment and, what is perhaps worse, exposing the babies to the risk of infected mothers' milk. These delays in obtaining the results, according to the doctors, are undermining efforts to provide better infant care. An editorial in the Times that day supported the need for providing speedier results.
It should be noted that hospitals are being sued by the HIV Law Project because, in their view, testing violates the civil rights of the mothers.
Home Spring 98 Full Screen
The TEACHERS CLEARINGHOUSE FOR SCIENCE AND SOCIETY EDUCATION