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Feb 11, 2023

Why Do Black Holes Twinkle? Scientists Studied 5,000 Star-Eating Behemoths to Find Out

Posted by in category: cosmology

Black holes are bizarre things, even by the standards of astronomers. Their mass is so great, it bends space around them so tightly that nothing can escape, even light itself.

And yet, despite their famous blackness, some black holes are quite visible. The gas and stars these galactic vacuums devour are sucked into a glowing disc before their one-way trip into the hole, and these discs can shine more brightly than entire galaxies.

Stranger still, these black holes twinkle. The brightness of the glowing discs can fluctuate from day to day, and nobody is entirely sure why.

Feb 11, 2023

New photodiode with extremely low excess noise for optical communication and long range LIDAR

Posted by in category: electronics

Optical pulses, which appear as a flash of light, are used to transmit information in high speed optical fibers, and are increasingly used in Light Detection And Ranging (LIDAR) for 3-dimensional imaging. Both of these applications demand light sensors or photodiodes that are capable of detecting very low levels of light intensity down to a few photons, where a single photon is the quantized energy unit of light.

A newly published paper, “Extremely low excess noise avalanche photodiode with GaAsSb absorption region and AlGaAsSb avalanche region,” in Applied Physics Letters, details a discovery by a Sheffield research team that has the capability to transform a single electron at its input to a cascade of electrons at its output.

This multiplication process is commonly known as avalanche breakdown, while a photodiode incorporating this process is called avalanche photodiode (APD). Though the application of reverse voltage, avalanche photodiodes (often referred to as APDs) have internal gain, which means that when compared to PIN-photodiodes they typically have a higher signal-to–.

Feb 11, 2023

This Week’s Awesome Tech Stories From Around the Web (Through February 11)

Posted by in category: internet

From A to B, check out this week’s awesome tech stories from around the web.

Feb 11, 2023

One Third of Americans Would Use Genetics Tech to Make Their Offspring Smarter, Study Finds

Posted by in categories: bioengineering, biotech/medical, genetics

Of the respondents, 28 percent said they were more likely than not to use gene editing to make their babies smarter, and 38 percent said they’d use polygenic screening. The researchers also noted what they called a bandwagon effect, where people who were told something along the lines of “everyone else is doing it” were more likely to say they’d do it too. This is logical; our comfort with decisions is buoyed by a sense that others in our shoes would choose similarly.

It’s important to note, though, that the survey made it clear that genetically enhancing embryos didn’t come with a guaranteed result of a smarter kid. “In this study, we stipulated a realistic effect—that each service would increase the odds of having a child who attends a top-100 college by 2 percentage points, from 3 percent to 5 percent odds—and lots of people are still interested,” said Michelle N. Meyer, chair of the Department of Bioethics and Decision Sciences at Geisinger and first author of the article.

The numbers—28 and 38 percent—don’t seem high. That’s a little below and a little above one-third of total respondents who would use the technologies. But imagine walking around in a world where one out of every three people had had their genes tweaked before birth. Unsettling, no? The researchers said their results point to substantial and growing interest in genetic technologies for offspring enhancement, and that now is the time to get a national conversation going around regulations.

Feb 11, 2023

Elusive transition shows universal quantum signatures

Posted by in categories: computing, quantum physics

There are stark differences between metals, through which electrons flow freely, and electrical insulators, in which electrons are essentially immobile. And despite the obvious difficulties in finding a way to switch back and forth from a metal to an insulator within one material, physicists are trying to figure out how.

“Say you want to put billions of circuit elements on a tiny chip and then control, at that microscopic scale, whether just one of the elements is metallic or insulating in a controlled fashion,” said Debanjan Chowdhury, assistant professor of physics in the College of Arts and Sciences. “It would be remarkable if you could control the microscopic device at the flick of a switch.”

Digging into recent past experimental results to try to reconcile experiment and theory, Chowdhury and doctoral candidate Sunghoon Kim found that even a tiny amount of imperfection, inherent in any real-life material, plays a key role in revealing the universal physics associated with the experimental metal-to-insulator transition (Physical Review Letters, “Continuous Mott Transition in Moiré Semiconductors: Role of Long-Wavelength Inhomogeneities”). Understanding the physics behind this mysterious phase transition could lead to new complex microscopic circuits, superconductors and exotic insulators that could find use in quantum computing.

Feb 11, 2023

Fighting brain cancer with bioadhesive nanoparticles

Posted by in categories: biotech/medical, nanotechnology, neuroscience

A team of researchers from Yale and the University of Connecticut (UConn) has developed a nanoparticle-based treatment that targets multiple culprits in glioblastoma, a particularly aggressive and deadly form of brain cancer.

The results are published in Science Advances (“Anti-seed PNAs targeting multiple oncomiRs for brain tumor therapy”).

A new treatment developed by Yale researchers uses bioadhesive nanoparticles that adhere to the site of the tumor and then slowly release the synthesized peptide nucleic acids that they’re carrying. In this image, the nanoparticles (red) are visible within human glioma tumor cells (green with blue nuclei). (Image: Yale Cancer Center)

Feb 11, 2023

Tassili n’Ajjer

Posted by in category: biological

Tassili n’Ajjer is a national park in the Sahara desert, located on a vast plateau in southeastern Algeria, bordering Libya, Niger, and Mali. It covers an area of roughly 80,000 sq. km. and contains one of the most important collections of prehistoric rock art in the world; it was inducted into the UNESCO World Heritage Site list in 1982. In 1986, UNESCO declared the area a Biosphere Reserve.

The plateau is composed largely of sandstone, and the natural erosion has resulted in hundreds of natural rock arches and other spectacular land formations — the ‘forests of stone’. Because of the altitude and the water-holding properties of the sandstone, the vegetation is somewhat richer than in the surrounding desert, and includes scattered woodland of the endangered endemic species of the Saharan cypress — one of the oldest trees in the world — and the Saharan myrtle. The literal English translation of Tassili n’Ajjer is ‘plateau of rivers’. Relict populations of the West African crocodile persisted in the Tassili n’Ajjer until the twentieth century. Various other fauna still reside on the plateau, including Barbary sheep, the only surviving type of the larger mammals depicted in the rock art of the area.

Feb 11, 2023

Stone Age discovery in Kenya fuels mystery of who made the earliest tools

Posted by in category: energy

NEW YORK (AP) — Archaeologists in Kenya have dug up some of the oldest stone tools ever found, but who used them is a mystery.

In the past, scientists assumed that our direct ancestors were the only toolmakers. But two big fossil teeth found along with the tools at the Kenyan site belong to an extinct human cousin known as Paranthropus, according to a study published Thursday in the journal Science.

This adds to the evidence that our direct relatives in the Homo lineage may not have been the only tech-savvy creatures during the Stone Age, said study author Rick Potts, director of the Smithsonian’s Human Origins Program.

Feb 11, 2023

Quantum entanglement maps gluons inside nuclei

Posted by in categories: mapping, quantum physics

Tomographic technique uses pions to analyse photon–gluon collisions.

Feb 11, 2023

Leonardo noted link between gravity and acceleration centuries before Einstein

Posted by in category: futurism

Caltech engineer Mory Gharib was poring over the digitized notebooks of Leonardo da Vinci one day, looking for sketches of flow visualization to share with his graduate students for inspiration. That’s when he noticed several small sketches of triangles, whose geometry seemed to be determined by grains of sand poured out from a jar. Further investigation revealed that Leonardo was attempting to study the nature of gravity, and the little triangles were his attempt to draw an equivalence between gravity and acceleration—well before Isaac Newton came up with his laws of motion, and centuries before Albert Einstein would demonstrate the equivalence principle with his general theory of relativity. [Edited for clarity.] Gharib was even able to re-create a modern version of the experiment.

Gharib and his collaborators described their discovery in a new paper published in the journal Leonardo, noting that, by modern calculations, Leonardo’s model produced a value for the gravitational constant (G) to around 97 percent accuracy. What makes this finding even more astonishing is that Leonardo did all this without a means of accurate timekeeping and without the benefit of calculus, which Newton invented in order to develop his laws of motion and universal gravitation in the 1660s.

“We don’t know if [Leonardo] did further experiments or probed this question more deeply,” Gharib said. “But the fact that he was grappling with the problems in this way—in the early 1500s—demonstrates just how far ahead his thinking was.”