Researchers from the Technical University of Denmark demonstrated a new nanotechnology-based printing technique that produces long-lasting color images on plastic at resolutions up to 127,000 dots per inch, many times more detailed than traditional laser printers. The system uses a laser to alter the structure of nanoscale structures on the plastic material. (A nanometer is one-billionth of a meter; a human hair is around 60,000 nanometers in diameter.) The nanoprinting technique could also lead to new kinds of 3D displays or invisible watermarks. From New Scientist : The surface of the plastic is shaped so that it has lots of tiny pillars, one roughly every 200 nanometers. A thin film of the element germanium is then spread over the plastic. Heat from a laser melts the germanium on each pillar, morphing its shape and thickness. As a result, it reflects a specific color. The coating protects the shapes of the newly carved nanostructures. Resonant laser printing of structural colors on high-index dielectric metasurfaces (ScienceAdvances)
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New ultra-high resolution printer makes colors from nanostructures
An anonymous reader writes: A recently released draft of the National Institute of Standards and Technology’s digital identity guidelines has met with approval by vendors. The draft guidelines revise password security recommendations and altering many of the standards and best practices security professionals use when forming policies for their companies. The new framework recommends, among other things: “Remove periodic password change requirements.” There have been multiple studies that have shown requiring frequent password changes to actually be counterproductive to good password security, said Mike Wilson, founder of PasswordPing. NIST said this guideline was suggested because passwords should be changed when a user wants to change it or if there is indication of breach. Read more of this story at Slashdot. 
Conventional wisdom: If you eat a lot of salt, you will get thirsty to dilute the sodium level in your blood. The excess salt will be excreted in your urine. But a new study of Russian cosmonauts is challenging this long-held belief. When the cosmonauts ate more salt, the became less thirsty. And their appetite increased – they had to eat 25 percent more to maintain their weight. From the New York Times : The crew members were increasing production of glucocorticoid hormones, which influence both metabolism and immune function. To get further insight, [Dr. Jens Titze, now a kidney specialist at Vanderbilt University Medical Center and the Interdisciplinary Center for Clinical Research in Erlangen, Germany] began a study of mice in the laboratory. Sure enough, the more salt he added to the animals’ diet, the less water they drank. And he saw why. The animals were getting water — but not by drinking it. The increased levels of glucocorticoid hormones broke down fat and muscle in their own bodies. This freed up water for the body to use. But that process requires energy, Dr. Titze also found, which is why the mice ate 25 percent more food on a high-salt diet. The hormones also may be a cause of the strange long-term fluctuations in urine volume. Scientists knew that a starving body will burn its own fat and muscle for sustenance. But the realization that something similar happens on a salty diet has come as a revelation. https://youtu.be/aJEzl31zL-I 
