Letters
Shafted
The photograph in "Relying on geology to jail nuclear waste" (SN: 11/1/97, p. 277) is indeed of a tunnel-boring machine. However, as the name suggests, these machines bore tunnels, not shafts.A horizontal or near-horizontal opening through rock is a tunnel; a vertical opening is a shaft.
Thomas J. Hydock
Minersville, Pa.Leafing out the tree of life
I've read about species extinctions in connection with biodiversity but never species creations ("Population Diversity Crowds the Ark," SN: 10/25/97, p. 260). Since evolution is a continuing process, I assume that new species are being added to the tree of life.Has anyone made a projection of the rate of species creation, or is that rate assumed to be at or near zero in the diversity calculations? If the creation rate is not known, how can we know whether the tree of life is becoming sparse or full?
A discussion of the rate of species creation would be an interesting article to balance out the picture.
Bob Lind
Inverness, Fla.Depending on the type of organism and the time period, it can take from tens of thousands of years to millions of years for a species to be created -- that is, for a single species to diverge into two (SN: 10/18/97, p. 251). Many biologists maintain that the present loss of biological diversity is on a par with the mass extinctions recorded in the fossil record, after which 5 million to 10 million years passed before species radiated and restored diversity to precrash levels. They also point out that the current large losses of tropical forests and other habitats that have been hotbeds of species creation are clipping the evolution of whole groups of organisms. -- C. Mlot
Life imitates art, baffles computer
It is such fun when life imitates an art form I love, in this case science fiction. "Immersion for analyzing complex software" (SN: 10/25/97, p. 261) discusses how computer programmers are creating three-dimensional representations of computer programs in virtual reality.Neither the author of the story nor the programmers involved mentioned the inventor of such representations: William Gibson, in his novel Neuromancer and his story "Burning Chrome." You shouldn't slight so good an author and envisioner of the future!
Fred Gilkey
Pittsburgh, Pa.A virtual reality arrangement for analyzing complex computer systems might be very useful for a system made up of software modules with conventionally engineered, preassigned functions. However, it is doubtful that such an approach would be suitable for the kind of neural network intended to simulate "how people think and how the brain works," as one researcher puts it.
This is because cognitive behavior most likely emerges from a large, distributed network of local processes; each one of these deals with low-level data unrelated to the sort of variables that would be meaningful to an investigator. In other words, major problems of internal representation remain unsolved for natural cognitive systems.
Paul B. Post
Norwalk, Conn.Power lines
Enjoyed the eye-opening "Must We Pull the Plug?" (SN: 10/25/97, p. 266).The cumulative demand of all our "leaky" appliances is indeed shockingly high, but aren't the digital clocks in many of these gadgets taking the place of many plug-in wall or shelf clocks? Also, today's quartz wall clocks are often battery-powered, eliminating a few more "watts from the wall."
It would be interesting to see research comparing the energy draw from those bygone electric clocks with the "leakage" powering the VCR and microwave clocks that replaced them!
Tom Robinson
Chicago, Ill.I've always used powerstrips with wall packs so I can power them off completely. I also use surge protectors for computers and my entertainment console, which, when I remember to do so, I also power off.
Bernie Rice
Park Forest, Ill.What good would it do to charge a battery to power memory chips and so on while an appliance is in the "off" position? The power ultimately has to come from the power station anyway. All the battery would do is make it less efficient than direct operation.
Walt Gray
Richland, Wash.If appliances were required to carry a notice of their standby wattage, it would give manufacturers an added incentive to demand innovative power-saving designs from their engineers.
Standby power drain is not new. Ever since they came out early in the century, doorbells have depended on continuously energized transformers, and the power company uses such transformers throughout the grid. Increased transformer efficiency would help.
Homer B. Tilton
Tucson, Ariz.The researchers are concerned about small energy consumers that account for about 5 percent of the power consumed by a typical household.
I am more concerned about the 95 percent that accrues through normal usage when appliances are turned on. I can turn off TV sets when they are not being watched. I have no way to make them more efficient.
Virgil H. Soule
Frederick, Md.
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Table
of Contents -- January 3, 1998
