Clearinghouse Update
From time to time we update our readers on situations which have been described in our Newsletter. One of those situations has been the controversy about exposure to electromagnetic fields (EMFs) from electric power lines, first raised by Irma Jarcho in her "Observations" column in our Fall 1990 issue. Since then Bob Neff has reviewed M. Granger Morgan's Electric and Magnetic Fields from 60 Herz Electric Power in our Winter 1991, and a more recent pamphlet from the National Institute of Environmental Health Sciences and the US Department of Energy -- Questions and Answers About EMF -- was listed as a resource in our Fall 1995 issue. Since our most recent update -- on page 18 of our Winter 1997 issue -- comes the result of a $4.5 million study conducted by the national Cancer Institute and published in the 3 July 1997 issue of the New England Journal of Medicine that found no solid evidence that living near high-voltage lines causes childhood leukemia.
Awards for Just Think
Just Think: Problem Solving Through Inquiry, the K-8 science video series and guidebook described on page 15 of our Fall 1996 issue, has received three awards for excellence. It was awarded the Crystal Award of Excellence in the Communicator Awards 1996 Video/Films competition; a third place "Certificate for Creative Excellence" in the 30th Anniversary United States International Film and Video Festival; and a bronze statuette in the film and video productions category of the 18th Annual Telly Awards.
Bartlett Takes on Simon
Al Bartlett, whose questioning of the connotation of sustainability was described on page 7 of our Fall 1995 issue, has published the eleventh in his series on the exponential function in the September 1996 issue of The Physics Teacher. Here he evaluates the arithmetic consequences of economist Julian Simon's assertion that "We have . . . the technology to feed, clothe and supply energy to an ever-growing population for the next 7 billion years . . . ." Even acknowledging Simon's correction of this quotation to "7 million years," Bartlett shows by calculating with the exponential function that the present world population increasing at a 1% annual rate for 7 million years would exceed the estimated number of atoms in the universe. Bartlett suggests that Simon and similar believers must belong to a New Flat Earth Society, because the finiteness of a spherical earth could never provide the infinite resources required by growth at any percentage rate.
Biological Detection of Explosives
Infusion Tip #2 of our Fall 1989 issue concerns the tradeoff between detecting bombs in luggage and false alarms. The method cited used nitrogen detection by neutron activation analysis, with neutrons provided by fission of Californium-252. The 21 April 1997 issue of Chemical and Engineering News reports development of a flow immunosensor at Naval Research Laboratory which can be used to detect TNT (2-,4-,6-trinitrotoluene) or RDX (1-,3-,5-trinitro-1-,3-,5-triazacyclohexane) in military superfund sites. Fluorescent analogs of TNT or RDX which saturate the binding sites of anti-TNT or anti-RDX antibodies are displaced by TNT or RDX if it is present. But though this method shows promise in evaluating superfund sites, it does not appear to lend itself to detecting bombs in luggage at airports.
Ballard's Latest Underwater Exploits
Our Fall 1995 issue included a review of the autobiography of Dr. Robert G. Ballard, a pioneer in ocean exploration. Ballard used deep ocean submersibles to discover the wrecks of the submarine Thresher, the Titanic, and the Bismarck. Ballard ended his book with his acceptance of the Presidency of the Institute for Exploration at Mystic, CT.
An article in the 31 July 1997 issue of The New York Times details the current work of the Institute. An expedition using the US Navy's NR-1 nuclear submarine found the largest concentration of ancient wrecks ever discovered -- eight sailing ships which now lie 2500 feet off the northwest coast of Sicily. Five ships were from Roman times, the oldest dating from about 100 B.C. Her holds were filled with amphorae. Another Roman ship, from the first century, AD, carried cut stone.
These findings disprove the notion -- long assumed by archeologists and historians -- that mariners in antiquity hugged the coast. The large number of wrecks ina small area indicate heavy traffic. Fortunatlely, deep sea wrecks are more likely to be intact, not broken up by waves or looted by treasure hunters, so they will offer valuable data on ancient shipping.
Ballard's success in finding the Titanic and other wrecks was in part due to his recognizing the "debris trails" left by the wrecks. Near Sicily he again found such debris trails-- where a ship in distress jettisoned cargo to save itself. Sometimes at the head of such a trail would be the wreck of the ship. If there was no wreck, presumably the ship survived the storm.
Next summer Ballard plans further exploration of Mediterranean routes but will also investigate shipping routes in the Black Sea. A whole new world of deep water archeology has now opened up using these research submarines developed for the Cold War.
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