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Readers Respond to the June 2019 Issue

Letters to the editor from the June 2019 issue of Scientific American

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Scientific American June 2019

DEFENDING MISSILE DEFENSE

Laura Grego and David Wright damningly criticize the U.S.’s Ground-based Midcourse Defense (GMD) program to intercept incoming nuclear missiles in “Broken Shield.” But your readers should not confuse what amounts to a debate over priorities with a claim grounded in established nuclear theory. In fact, ballistic missile defense (BMD) can limit nuclear damage, buttress U.S. deterrence and empower arms control.

The missiles BMD shoots down are not the only ones that it impacts. Rather the possibility of directing all BMD to protect, say, Washington, D.C., forces U.S. adversaries to allocate additional warheads to “must kill” targets; accordingly, these bombs are then unavailable for lower-priority cities. A missile shield does not have to be perfect to successfully defend against an attack from a small nuclear power—such as North Korea. And BMD raises the bar for a successful nuclear strike, even for Russia’s larger nuclear arsenal.


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MARK MASSA Washington, D.C.

BAR-CODING FIX FOR DRUGS

In “All the World’s Data Could Fit in an Egg,” James E. Dahlman describes how the method of DNA tagging could reduce effort in investigating potential drugs. That sounds like an awesome development, but I wonder if the method could be used for another concern as well.

The fine print for many drugs, particularly psychotropic ones, often says something on the order of “we don’t really know how this works,” and they can have severe adverse reactions, sometimes even increasing the possibility for violence and suicide. Might DNA bar coding also be used to reduce such reactions?

MORITZ FARBSTEIN St. Louis

DAHLMAN REPLIES: DNA bar coding could eventually alleviate adverse reactions by helping scientists design drugs that specifically target diseased cells. Many such reactions occur when a drug meant to treat a diseased cell also targets a healthy one. By maximizing the drug delivered to the site of disease, it may be possible to reduce the dose and minimize interaction between that drug and healthy cells. Using DNA bar codes, scientists can track how drugs are delivered to diseased and healthy cells, all in one experiment. The hope is to use these data to rationally design drugs that avoid healthy cells.

AWAKE WHILE ASLEEP

“One Eye Open,” by Gian Gastone Mascetti, describes how some animals can sleep with one half of their brain while the other stays awake, sometimes keeping one eye open while they do so. The article particularly caught my interest because I experienced an effect like this often while serving on the front lines in Iraq and Afghanistan.

When I was sleeping, I knew I was asleep, but I was also awake and aware of everything going on around me. I was able to come fully awake in an instant, as if I had never even been asleep, but I felt rested. And I could open one eye slightly to see what was happening around me. This happened many nights in a row, over many months. I’ve only experienced it when my life was in danger, so it was clearly connected to a sense of life and death hanging on whether I could remain alert.

MIKE SCOTT via e-mail

MASCETTI REPLIES: To my knowledge of human sleep behavior, sleeping with one eye open seems to be a metaphor or perhaps a sensation some people experience when sleeping in new, alarming and potentially dangerous conditions. But I cannot exclude the possibility that some individuals might show the capacity to briefly open one eye and awaken during sleep as has been reported in some species of birds. And we do know that humans are able to show a sleep strategy that seems to be reminiscent of the unihemispheric slow-wave sleep in animals I discuss in my article. When sleeping, they show a consistent electroencephalographic slow-wave activity in one hemisphere, indicating a very light sleep level in the other hemisphere.

A hemispheric sleep asymmetry could be present in any unusual, unsafe or dangerous environment, allowing the sleeper to keep a certain level of vigilance. For example, it has been shown that sleeping mothers maintain a high vigilance and a low awakening threshold to smell, noises and the cries of their babies. This hemispheric condition should indeed also be present in soldiers sleeping in a war zone.

BAT BUDDIES

In “Deer Friends” [Advances], Joshua Rapp Learn reports on a study finding that bats follow white tail deer around to prey on insects. That observation is not unique: When my wife is out working on our farm at dusk, several resident little brown bats that nest under the shingles of our house follow her around, preying on mosquitoes. My wife attracts the bugs, and the bats eat them—a perfect symbiosis, as the article notes about the arrangement between bats and deer. We live almost mosquito-free in the summer, and our bat friends keep my wife company at night.

JOHN DAVIES Sunshine Coast, B.C.

ASSISTED MISGIVING

What planet is Wade Roush living on? In “Safe Words for Our AI Friends” [Ventures], he says, “AI assistants should exist to give us more agency over our lives.” But by being too lazy to look up a weather report or turn on lights, he apparently allows an ever present listening device—Amazon’s Alexa—to hear everything. That seems to be a clear transference of agency.

Further, Roush says he wants such assistants that won’t compromise privacy, transparency, security and trustworthiness. Has that ever happened with any online platform? It is naive to think things will ever be different.

HARLAN LEVINSON Los Angeles

PLASTICS AT HOME

I could not ignore the irony of tearing the plastic outer packaging from the June issue and throwing it in the trash so that I could read the editorial entitled “What to Do about Plastic Pollution” [Science Agenda]. As a longtime subscriber, I ask you to please stop wrapping your magazine in unnecessary plastic packaging. I don’t mind reading an issue that arrives slightly wrinkled.

SCOTT PIERCE Western Carolina University

THE EDITORS REPLY: Scientific American wraps issues in plastic for U.S. subscribers only when there is an unbound advertising supplement included in the mailing. The current issue (October), which includes such a supplement, is the seventh mailing of that kind since the beginning of 2017 (newsstand issues are never wrapped). A small number of domestic subscribers and advertisers request wrapped issues, and we wrap issues for all international subscribers (except in Canada). This adds up to only 10 percent of the total print run, but we realize that even that portion contributes to the burden of plastic pollution worldwide, and we are committed to doing better. We are actively investigating options to cease wrapping entirely or to replace our current material with a more sustainable alternative.

ERRATUM

“The Deepest Recesses of the Atom,” by Abhay Deshpande and Rikutaro Yoshida, should have said that quarks, rather than nucleons, are at least 10,000 times smaller than a proton. Protons are one type of nucleon.

Scientific American Magazine Vol 321 Issue 4This article was originally published with the title “Letters” in Scientific American Magazine Vol. 321 No. 4 (), p. 8
doi:10.1038/scientificamerican1019-8