See below for exciting content in the September–October 2014 issue of
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In this issue of
American Scientist Update:
• Warming climate threatens New Zealand’s tuatara
• The sleuth who found gaps in the periodic table
• How the brain tells the hand to grasp
• Dangerous twists in Earth’s radiation belts
• Quietest places in the world
A Threat to New Zealand’s Tuatara Heats Up
Rising temperatures are causing this ancient reptile to produce more male offspring.
It may look like a lizard, but the tuatara is a remnant of an ancient lineage of reptiles in New Zealand and is an important case study for workable conservation measures for isolated, endangered creatures. Slow to respond to environmental changes, the long-lived tuatara is particularly susceptible to a warming climate. Its sex, like that of many reptiles, is determined by temperature. Biologists Kristine L. Grayson, Nicola J. Mitchell, and Nicola J. Nelson describe their research showing that the tuatara population of North Brother Island in New Zealand could become entirely composed of males.
Master of Missing Elements
Henry Moseley’s discovery of atomic charges was key to uncovering gaps not yet filled on the periodic table, and transformed the chemistry world.
X-rays diffracted from elements could be used to determine an element’s atomic charge, or atomic number. This data led British chemist Henry Moseley to realize that elements on the periodic table should be reordered by atomic number, not weight as they had been before. Science historian and philosopher Eric R. Scerri brings Moseley’s discovery from the early 1900s to light, as well as its significance: Moseley’s work revealed gaps to be filled by elements yet to be discovered.
What’s in a Grasp?
Simple acts of picking up a water glass or turning a handle are products of multilayered cognitive plans and sophisticated neural computations.
Do you realize how incredibly smart you have to be to know how to reach out for your coffee cup and lift it to your mouth? The authors, led by David A. Rosenbaum, explore the surprisingly complex brain activity that underlies the mundane process of grasping and manipulating an object. Their findings could lead to improvements in robotics as well as rehabilitation therapy.
New Twists in Earth’s Radiation Belts
Changes in the rings of high-energy particles that encircle our planet could amplify damage from solar storms.
Earth is enshrouded in belts of extraordinarily high-energy, high-intensity radiation, called the Van Allen belts. Solar storms and space weather can pump them up, making the radiation zones around Earth more dangerous for days or even weeks on end, but details of their behavior are still only roughly understood. New research shows that the belts can quickly reconfigure their structure and density, on the range of seconds to hours. Other observed events show the interplay between the belts’ own internal magnetic acceleration of particles and the influx of energy from space weather. The results may help protect communications satellites and power grids on Earth; the research can also be extrapolated to help researchers understand what’s happening on other planets inside and outside our Solar System. Astrophysicist Daniel Baker, who is involved with these studies, goes into detail about these events and their consequences.
Quietest Places in the World
The search for extreme silence leads one researcher to remote deserts, secluded forests, and into an artificial environment so noise-free it is unbearable.
Finding locations that are truly silent is not easy. In fact, it is impossible: In a silent place, auditory neurons in the brainstem increase the amplification of the signals from the auditory nerve to compensate for the lack of external sound. As an unwanted side effect, spontaneous activity in the auditory nerve fibers increases, leading to neural noise that is perceived as a whistle, hiss, or hum. For people with tinnitus—a persistent ringing or whooshing in the ears—the effect is even more pronounced. For these reasons, Trevor Cox, an acoustic engineer, reveals that the most relaxing silence is not silence at all, but an experience in which nature provides just enough background noise to create an auditory anchor.
In our Spotlight section, American Scientist senior editor Sandra J. Ackerman discusses an intriguing session on the new science of ancient DNA that is shedding light on prehistoric times, presented at the 2014 Euroscience Open Forum (ESOF) meeting she attended in Copenhagen. Also, associate editor Katie L. Burke interviews biologist Joan Strassmann about her and her husband’s research on Dictyostelium discoideum, an amoeba that is delivering major insights into the evolution of cooperative behaviors.
In our Perspective, biologist Robert L. Dorit explores the microbiome, the bacterial life living on and in our bodies. Studies of the microbiome are challenging previously held notions in community ecology. Dorit discusses why our local bacteria should not be viewed with negativity, but instead should be understood as a major influence to human health, digestion, metabolism, and response to medicines.
In our Technologue column, biomechanics engineer Stephen Piazza answers a hot-topic question: Why is it so hard to stop sports concussions? By examining the way human behavior conspires with the complex mechanics of head impacts that result in high injury rates, Piazza suggests that new helmet technology could be the key to reducing the injury rates.
This issue’s Sightings showcases digital scans and computer-aided models that visually liberate ancient fossils from stone. The results are more than beautiful: Catherine Clabby examines how paleontologists use high-resolution x-ray microtomography to study the exteriors and interiors of fossils at a microscopic scale and in three dimensions.
In our Engineering column, Henry Petroski talks about how, from the construction of the Erie Canal to today, companies and schools have tried many creative ways to find enough skilled, professional workers for various engineering projects. He discusses how these efforts have changed over the decades in response to influences ranging from the first big civil engineering projects to the rise of the modern auto industry to the launch of Sputnik.
In our Computing Science column, Brian Hayes writes about how mathematician William Shanks computed the value of pi by hand in the 1850s. Using forensic mathematics, Hayes also deduces when and how this heroic effort went tragically awry.
In our Arts Lab column, neuroscientist-artist Greg Dunn reveals a new way to comprehend the incredibly complex wiring of the brain. He visualizes networks of neurons in the cerebral cortex by taking inspiration from the materials and techniques of Asian scroll painting.
In our Scientists’ Nightstand section, our reviewers provide an in-depth analysis of the chemistry behind making cheese; discuss wild answers to whimsical “what if?” questions in science, technology, and math; and look at rich, colorful catalogs depicting bird varieties from the past and in a fanciful future.
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