New research from UCL shows we will soon uncover the origin of the ultraviolet light that bathes the cosmos, helping scientists understand how galaxies were built.
The study published in The Astrophysical Journal Letters by UCL cosmologists Dr Andrew Pontzen and Dr Hiranya Peiris (both UCL Physics & Astronomy), together with collaborators at Princeton and Barcelona Universities, shows how forthcoming astronomical surveys will reveal what lit up the cosmos. (more…)
Dawn triggers basic biological changes in the waking human body. As the sun rises, so does heart rate, blood pressure and body temperature. The liver, the kidneys and many natural processes also begin shifting from idle into high gear. Then as daylight wanes and darkness descends, these processes likewise begin to subside, returning to their lowest levels again as we sleep.
These internal biological patterns are tightly linked to an external cosmic pattern: the earth’s rotation around the sun once every 24 hours. This endless loop of light and darkness and the corresponding synchrony of internal and external clocks, are called circadian rhythms, from “circa diem,” Latin for “approximately a day.” Circadian rhythms influence almost all living organisms, from bacteria to algae, insects, birds and, as is increasingly understood by science, humans beings. (more…)
Researchers have strengthened their understanding of how skin cells called melanocytes sense ultraviolet light and act to protect themselves with melanin. In a new study, they report experiments showing that an ion channel well-known elsewhere in the body for its chemical sensitivity, plays a central role in this process. (more…)
Berkeley Lab Scientists at Advanced Light Source Show Dislocations Can Be Induced by Pressure in Ultrafine Nanocrystals
Nanocrystals as protective coatings for advanced gas turbine and jet engines are receiving a lot of attention for their many advantageous mechanical properties, including their resistance to stress. However, contrary to computer simulations, the tiny size of nanocrystals apparently does not safeguard them from defects.
In a study by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab)and collaborators from multiple institutions, nanocrystals of nickel subjected to high pressure continued to suffer dislocation-mediated plastic deformation even when the crystals were only three nanometers in size. These experimental findings, which were carried out at Berkeley Lab’s Advanced Light Source (ALS), a premier source of X-rays and ultraviolet light for scientific research, show that dislocations can form in the finest of nanocrystals when stress is applied. (more…)
Engineering faculty and students at the University of Colorado Boulder have produced the first experimental results showing that atomically thin graphene membranes with tiny pores can effectively and efficiently separate gas molecules through size-selective sieving.
The findings are a significant step toward the realization of more energy-efficient membranes for natural gas production and for reducing carbon dioxide emissions from power plant exhaust pipes.
Mechanical engineering professors Scott Bunch and John Pellegrino co-authored a paper in Nature Nanotechnology with graduate students Steven Koenig and Luda Wang detailing the experiments. The paper was published Oct. 7 in the journal’s online edition. (more…)
Using the world’s fastest laser pulses, which can freeze the ultrafast motion of electrons and atoms, UA physicists have caught the action of molecules breaking apart and electrons getting knocked out of atoms. Their research helps us better understand molecular processes and ultimately be able to control them in many possible applications.
In 1878, a now iconic series of photographs instantly solved a long-standing mystery: Does a galloping horse touch the ground at all times? (It doesn’t.) The images of Eadweard Muybridge taken alongside a racetrack marked the beginning of high-speed photography.
Approximately 134 years later, researchers in the University of Arizona department of physics have solved a similar mystery, one in which super-excited oxygen molecules have replaced the horse, and ultrafast, high-energy laser flashes have replaced Muybridge’s photo emulsion plates. (more…)
Analysis of data from the National Science Foundation’s South Pole Telescope, for the first time, more precisely defines the period of cosmological evolution when the first stars and galaxies formed and gradually illuminated the universe. The data indicate that this period, called the epoch of reionization, was shorter than theorists speculated — and that it ended early.
“We find that the epoch of reionization lasted less than 500 million years and began when the universe was at least 250 million years old,” said Oliver Zahn, a postdoctoral fellow at the Berkeley Center for Cosmological Physics at the University of California, Berkeley, who led the study. “Before this measurement, scientists believed that reionization lasted 750 million years or longer, and had no evidence as to when reionization began.” (more…)
ANN ARBOR, Mich.— A smart filter with a shape-shifting surface can separate oil and water using gravity alone, an advancement that could be useful in cleaning up environmental oil spills, among other applications, say its University of Michigan developers.
The system could provide a more efficient way to remove crude oil from waterways without using additional chemical detergents, or even after detergents have been added, said Anish Tuteja, an assistant professor of materials science and engineering. Tuteja is the corresponding author of a paper on the research published in the Aug. 28 issue of Nature Communications.
The researchers created a filter coating that repels oil but attracts water, bucking conventional materials’ properties. Most natural substances soak up oil, and the few that repel it also repel water because water has a higher surface tension. (more…)
