Abra Science

 In underwater acoustics, deep learning is gaining traction in improving sonar systems to detect ships and submarines in distress or in restricted waters. However, noise interference from the complex marine environment becomes a challenge when attempting to detect targeted ship-radiated sounds. ABNN’s gradual focus on specific line-spectrum features of a ship. CREDIT: Institute of Acoustics, Chinese Academy of Sciences In The Journal of the Acoustical Society of America, published by the Acoustical Society of America through AIP Publishing, researchers in China and the United States explore an attention-based deep neural network (ABNN) to tackle this problem. “We found the ABNN was highly accurate in target recognition, exceeding a conventional deep neural network, particularly when using limited single-target data to detect multiple targets,” co-author Qunyan Ren said. Deep learning is a machine-learning method that uses artificial neural networks inspired by the human bra...

  An image of Neptune from Voyager 2. Credit: NASA/JPL-Caltech Deep inside Neptune and Uranus, temperatures and pressures are extreme enough to produce superionic water—a phase in which oxygen ions crystallize while highly mobile hydrogen ions float through interstitial spaces. Information about superionic water’s phase behavior would help planetary scientists model and understand the ice giants’ evolution, structure, and unusual magnetic fields. Theoretical and computational studies of superionic water’s structure and stability have supplemented scarce experimental data—the phase was observed for the first time in 2019. But those have yielded limited, and sometimes contradictory, results. Now Bingqing Cheng at the University of Cambridge and her collaborators have made predictions about superionic water’s lattice structure at planetary conditions by simulating the material using machine-learning potentials (MLPs) and an artificial neural-network architecture. Molecular-dyn...

The pandemic-related drop in greenhouse gas emissions in 2020 was likely the largest on record in a single year, but how our recovery might affect future emissions is less clear. New modeling examines alternative scenarios and how they could impact climate mitigation targets. A group of IIASA researchers in the Energy, Climate, and Environment Program performed a bottom-up assessment of changes in energy-related demand and estimated how new patterns of travel, work, consumption, and production might reduce or increase climate mitigation challenges. "Many people have been wondering what the large changes in societies that came with the COVID-19 pandemic and its lockdowns mean for climate change," says Jarmo Kikstra, lead author of the study. "If societies are just moving back to old practices, the answer is that there is virtually no effect. However, if some of the changes in energy-use practices persist, climate mitigation challenges will be affected." The r...

  Artist’s illustration of hydrodynamical behavior from an interacting ensemble of quantum spin defects in diamond. Credit: Norman Yao/Berkeley Lab In 1998, researchers including Mark Kubinec of UC Berkeley performed one of the first simple quantum computations using individual molecules. They used pulses of radio waves to flip the spins of two nuclei in a molecule, with each spin's "up" or "down" orientation storing information in the way that a "0" or "1" state stores information in a classical data bit. In those early days of quantum computers, the combined orientation of the two nuclei that is, the molecule's quantum state could only be preserved for brief periods in specially tuned environments. In other words, the system quickly lost its coherence. Control over quantum coherence is the missing step to building scalable quantum computers. Now, researchers are developing new pathways to create and protect quantum coherence. Do...

  Disordered carbon anodes for Na-ion batteries quo vadis? Credit: Science China Press Na-ion batteries (NIBs) are gradually attracting much attention as an alternative to lead-acid batteries and supplement to Li-ion batteries (LIBs) owing to the abundant Na resources and excellent cost-effectiveness. Since the most commonly used graphite as an anode material in LIBs cannot be inherently used in NIBs, tremendous efforts have been made to advance the fundamental understanding and design of suitable anode materials for NIBs, including the improvement of Na storage capacity and the study on Na storage mechanisms. According to all these studies, disordered carbons are now the most promising anode candidates for NIBs. Nevertheless, there are still many challenges need to be addressed, and the further exploration of disordered carbon anodes is very important in the future. Recently, Prof. Yong-Sheng Hu and Prof. Yaxiang Lu from Institute of Physics, Chinese Academy of Sciences sy...

  This deep Hubble Space Telescope image reveals the diffuse dwarf galaxy NGC2052-DF2, an unusual “see-through” galaxy. The giant cosmic cotton ball is so diffuse and its ancient stars so spread out that distant galaxies in the background can be seen through it. Astronomers measured the luminosities of faint stars at the tip of the red giant branch in this galaxy to improve the accuracy of its distance and to conclude that, in agreement with earlier studies, it does appear to be very deficient in dark matter. Credit: Science: NASA, ESA, STScI, Zili Shen (Yale), Pieter van Dokkum (Yale), Shany Danieli (IAS) Image Processing: Alyssa Pagan (STScI) The galaxy NGC 1052-DF2 resides in a field of galaxies about sixty-five million light-years away. Its low mass, only about two hundred million solar-masses, makes it a “dwarf” and its size, about fifteen thousand light-years in diameter, places it in the regime of ultra-diffuse galaxies. It is also distinguished by hosting a large populatio...

 Fraudulent practices in food production, especially false claims of geographical origin, cause billions of dollars in economic damage every year. Botanists at the University of Basel have now developed a model that can be used to determine the origin of food in an efficient and low-cost manner. Strawberries from Switzerland or olive oil from Italy can be sold at much higher prices than the same products from other countries. Both the authorities and the food industry spend a great deal of time fighting false declarations of geographical origin that are assumed to cause an estimated USD 30 million to 40 billion a year in economic damage. One method for detecting food fraud is to determine the δ18O (delta-O-18) value of a product sample, which characterizes the oxygen isotope ratio. Until now, this procedure has been highly time consuming and costly. A case of suspected fraud involved not only collecting reference data from the claimed country of origin, but also comparative data fr...