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Apr 27, 2023

Bringing Interferometric Imaging into the X-Ray Regime

Posted by in categories: particle physics, quantum physics, space

The experimental realization of a recently proposed technique points to new possibilities for imaging molecules using x rays.

Hanbury Brown and Twiss (HBT) interferometry [1] is a versatile technique widely used in various fields of physics, such as astronomy, quantum optics, and particle physics. By measuring the correlation of photon arrival times on two detectors as a function of the photons’ spatial separation, HBT interferometry enables the determination of the size and spatial distribution of a light source. Recently, a novel x-ray imaging technique based on the HBT method was proposed to image the spatial arrangement of heavy elements in a crystal or molecule by inducing those elements to fluoresce at x-ray wavelengths [2].

Apr 27, 2023

Turbulence in Collisionless Cosmic Plasmas

Posted by in categories: computing, cosmology, particle physics

New computer simulations show that wave-particle interactions endow thin plasmas with an effective viscosity that regulates their turbulent motions and heating.

Most of the regular matter in the Universe is plasma, an ebullient state characterized by charged particles interacting collectively with electromagnetic fields. When individual particles collide on scales much shorter than those of bulk plasma motions, the latter are described well by a 3D fluid theory: magnetohydrodynamics. That condition prevails in the interiors of stars and planets and in protoplanetary accretion disks. But many hot, low-density astrophysical plasma flows are only weakly collisional. Accounting for stellar winds, accretion around black holes, and the motions of the plasma that pervades intergalactic space requires a statistical kinetic description of the particle positions and velocities in a 6D space. Numerical simulations by Lev Arzamasskiy of the Institute of Advanced Study in Princeton, New Jersey, and his colleagues [1] shed new light on magnetized kinetic turbulence in such plasmas.

Apr 27, 2023

Genomes from 240 mammalian species reveal what makes the human genome unique

Posted by in categories: biotech/medical, evolution, existential risks, genetics, health

Over the past 100 million years, mammals have adapted to nearly every environment on Earth. Scientists with the Zoonomia Project have been cataloging the diversity in mammalian genomes by comparing DNA sequences from 240 species that exist today, from the aardvark and the African savanna elephant to the yellow-spotted rock hyrax and the zebu.

This week, in several papers in a special issue of Science, the Zoonomia team has demonstrated how can not only shed light on how certain species achieve extraordinary feats, but also help scientists better understand the parts of our genome that are functional and how they might influence health and disease.

In the new studies, the researchers identified regions of the genomes, sometimes just single letters of DNA, that are most conserved, or unchanged, across mammalian species and millions of years of evolution—regions that are likely biologically important. They also found part of the genetic basis for uncommon mammalian traits such as the ability to hibernate or sniff out faint scents from miles away. And they pinpointed species that may be particularly susceptible to extinction, as well as genetic variants that are more likely to play causal roles in rare and common human diseases.

Apr 27, 2023

DNA methylation markers for increased risk of schizophrenia identified for first time in newborns

Posted by in categories: biotech/medical, neuroscience

An international research team led by investigators at Virginia Commonwealth University has identified for the first time markers that may indicate early in life if a person has susceptibility to schizophrenia.

The ability to predict the risk of developing later in life may allow early detection and intervention, which the researchers hope can reduce the impact of the disease on individuals, families and communities. Their results have been published in Molecular Psychiatry.

Schizophrenia is a serious psychiatric disorder that is most often detected in young adulthood. It affects as much as 1% of the and can cause debilitating effects such as a sense of losing touch with reality. People with the disorder are up to three times more likely to die early and often face discrimination, social isolation and debilitating physical illness, according to the World Health Organization.

Apr 27, 2023

Engineers ‘grow’ atomically thin transistors on top of computer chips

Posted by in categories: particle physics, robotics/AI

Emerging AI applications, like chatbots that generate natural human language, demand denser, more powerful computer chips. But semiconductor chips are traditionally made with bulk materials, which are boxy 3D structures, so stacking multiple layers of transistors to create denser integrations is very difficult.

However, semiconductor transistors made from ultrathin 2D materials, each only about three atoms in thickness, could be stacked up to create more powerful chips. To this end, MIT researchers have now demonstrated a that can effectively and efficiently “grow” layers of 2D transition metal dichalcogenide (TMD) materials directly on top of a fully fabricated silicon chip to enable denser integrations.

Growing 2D materials directly onto a silicon CMOS wafer has posed a major challenge because the process usually requires temperatures of about 600 degrees Celsius, while silicon transistors and circuits could break down when heated above 400 degrees. Now, the interdisciplinary team of MIT researchers has developed a low-temperature growth process that does not damage the chip. The technology allows 2D semiconductor transistors to be directly integrated on top of standard silicon circuits.

Apr 27, 2023

Light Steering Technologies claims $1.25 million Air Force contract

Posted by in categories: business, transportation

SAN FRANCISCO –New Hampshire startup Light Steering Technologies won a $1.25 million U.S. Air Force contract for angular pointing technology with small satellite applications.

Through the contract with AFWERX, the Air Force organization focused on innovation, LST aims to advance the Technology Readiness Level, or technological maturity, of its Multi-Axis Scanner. LST’s Multi-Axis Scanner is a patented magnetic joint for gimbal-like capability.

“What’s compelling about the technology is we are minimizing the moving mass,” Aaron Castillo, LST senior vice president of business development and program management, told SpaceNews. “This is achieved by actuating a mirror instead of the entire satellite bus or using a traditional gimbal mechanism.”

Apr 27, 2023

NIWC Pacific and its partners are building a quantum Navy

Posted by in categories: mathematics, particle physics, quantum physics

For one, classical physics can predict, with simple mathematics, how an object will move and where it will be at any given point in time and space. How objects interact with each other and their environments follow laws we first encounter in high school science textbooks.

What happens in minuscule realms isn’t so easily explained. At the level of atoms and their parts, measuring position and momentum simultaneously yields only probability. Knowing a particle’s exact state is a zero-sum game in which classical notions of determinism don’t apply: the more certain we are about its momentum, the less certain we are about where it will be.

We’re not exactly sure what it will be, either. That particle could be both an electron and a wave of energy, existing in multiple states at once. When we observe it, we force a quantum choice, and the particle collapses from its state of superposition into one of its possible forms.

Apr 27, 2023

Marvel Director Expects Fully AI-Generated Movies Within Two Years

Posted by in categories: entertainment, robotics/AI

Joe Russo, a director who’s helmed some of Marvel’s biggest movies, thinks it’s only a matter of time before AIs can make legit films.

Apr 27, 2023

WHO: biological hazard brewing in Sudan as fighters overtake a central public health lab

Posted by in category: biological

A fighting faction in Sudan has occupied the country’s main public health lab, putting pathogen collections at risk, the WHO said.

Apr 27, 2023

Newly observed effect makes atoms transparent to certain frequencies of light

Posted by in category: particle physics

A newly discovered phenomenon dubbed “collectively induced transparency” (CIT) causes groups of atoms to abruptly stop reflecting light at specific frequencies.

CIT was discovered by confining ytterbium atoms inside an —essentially, a tiny box for light—and blasting them with a laser. Although the laser’s light will bounce off the atoms up to a point, as the frequency of the light is adjusted, a transparency window appears in which the light simply passes through the cavity unimpeded.

“We never knew this transparency window existed,” says Caltech’s Andrei Faraon (BS ‘04), William L. Valentine Professor of Applied Physics and Electrical Engineering, and co-corresponding author of a paper on the discovery that was published on April 26 in the journal Nature. “Our research has primarily become a journey to find out why.”