A patch of ocean south-east of Greenland is the only place on Earth that is cooling, and it could be a sign that the warm water “conveyor belt” in the Atlantic is slowing down
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No Free Lunch for Sound Waves
Sound wave scattering can be increased in one frequency range only by reducing scattering in another range, according to experiments—a discovery relevant for acoustic engineering.
Acoustic metamaterials allow blocking, absorbing, or redirecting waves in ways not possible with conventional materials. Now researchers have shown that all such structures face a previously unrecognized constraint: The total acoustic scattering is fixed, so that boosting scattering in one frequency band necessarily depletes it elsewhere [1]. This general restriction provides a new way of thinking about how acoustic performance can be optimized, which could guide the design of broadband sound-control devices, from noise barriers to acoustic cloaks.
By building structures into materials on length scales smaller than the wavelength of sound, researchers can create artificial resonant elements that interact strongly with acoustic waves. Such structures can produce effects that are difficult or impossible to achieve otherwise—for example, strong sound attenuation through thin material layers. Such advances have led to new techniques for lightweight soundproofing and sound steering.
A new strategy for assembling π-conjugated panels into square molecules revealed
A research group has developed a new method for selectively synthesizing three-dimensional macrocycles,⁽¹⁾ in which four panels are arranged in a square, by connecting planar π-conjugated molecules⁽²⁾ at right angles.
This method is applicable to a wide variety of π-conjugated molecules and allows the size of the internal cavity to be designed. Furthermore, the resulting square macrocycles exhibit acid responsiveness, reversibly changing color under the action of a mild acid, while acid-mediated hydrolysis enables the starting monomers to be recovered in high yield—realizing a sustainable molecular synthesis that reverts to and regenerates the starting materials. The originality of this work lies in having a single imine bond play three roles: creating the shape, responding to stimuli and reverting back.
These research results were published in the Journal of the American Chemical Society on Monday, June 1, 2026. The team includes Associate Professor Yasutomo Segawa and Assistant Professor Takashi Harimoto at the Institute for Molecular Science (National Institutes of Natural Sciences) and the Graduate University for Advanced Studies (SOKENDAI).
Semiconductors enter ‘multi-tasking’ era: New device cuts required components by 75% and quadruples processing speed
Less than two decades after smartphones fit into the palm of our hands, artificial intelligence is now running on devices worn on our wrists. The challenge is that while devices continue to shrink, the amount of data they must process and the number of functions they must perform are growing exponentially. A research team at POSTECH (Pohang University of Science and Technology) has found a promising way to address this contradiction.
A team led by Professor Byoung Hun Lee of the Department of Electrical Engineering and the Department of Semiconductor Engineering at POSTECH, together with Dr. Jae Hyeon Jun of the Department of Electrical Engineering, has developed a transistor technology that enables a single semiconductor device to perform multiple circuit functions simultaneously. The new approach significantly simplifies circuit design and increases data processing speed fourfold compared with conventional methods. The findings were published in Advanced Functional Materials.
One of the key challenges in the semiconductor industry is integrating more functions into smaller chips. As the number of functions increases, so do the number of circuits and transistors required. However, when adding new functions to previously fabricated semiconductor chips, back-end-of-line processing must be conducted at temperatures below 400 C to protect the existing chip structure.
AI fails classic attention test, with longer word lists triggering dramatic accuracy collapse
Giving AI a classic psychological test reveals an inherent weakness in LLM decision-making abilities. Suketu Patel and colleagues explored how transformer-based machine attention differs from human attention by testing AI models on the “Stroop task,” in which words for colors are printed in colored ink, and participants are asked to name the ink color of each word while ignoring its meaning.
The findings are published in the journal PNAS Nexus.
The task is clinically used to assess executive control, especially a person’s ability to inhibit an automatic response. Although humans generally take longer to answer correctly when words and colors are mismatched than when they match, they can still perform stably and with high accuracy even on long word lists.
Did this star eat its planets? A new study offers clues on ‘chemical paradox’ of a binary system
Astronomers have investigated a puzzling binary star system in which two stars that may have formed together now show dramatically different chemical compositions. The new study, uploaded to the arXiv preprint server on May 29, hints at the possibility that one of the stars may have swallowed its own planets.
Generally, in binary systems, the two stars form from the same molecular cloud and, as a result, have the same age and chemical composition. Any differences in their metallicity, astronomers say, hint at an event involving mass transfer or engulfment of planetary components or other internal processes. HD 81,809 is one such peculiar system in which the stars are both sun-like G stars but are at different stages of evolution.
The primary star, HD 81809A, has crossed the main-sequence phase, depleted its hydrogen fuel in the core but hasn’t turned into a giant star yet—it is now a subgiant. On the other hand, the secondary star, HD 81809B, is still a main-sequence star. It has lithium enrichment and there is a difference in iron content between the two stars—the primary is metal-poor with an iron abundance of −0.57 dex, while the secondary has roughly solar metallicity around 0.00 dex.
Critical Te-104 decay measurements may help answer century-old alpha particle formation question
University of Tennessee, Knoxville physicists and their colleagues have made critical measurements of the lifetime and decay energy of tellurium-104 (Te-104), an important step in answering a century-old question and understanding how hundreds of nuclei decay. The results are published in Nature.
Professor Robert Grzywacz led the experimental team at the Radioactive Isotope Beam Factory (RIBF) at RIKEN in Japan. He explained how the results match decades-old predictions that tellurium-104 is a special case in alpha decay, a process where an alpha particle (a strongly bound system of two protons and two neutrons) tunnels through the barrier surrounding the nucleus where it resides. Though alpha radioactivity was discovered more than 125 years ago, where the particle comes from is still a mystery, especially in nuclei that have large numbers of protons and neutrons.
“Alpha decay is the oldest decay mode,” Grzywacz said. “The big question is how the alpha particle forms in heavy nuclei, which are known to have uniform matter distribution. There must be a mechanism which causes local ‘clump’ or ‘cluster’ formation.”
Light pulses uncover Higgs mode that reshapes perovskite crystal symmetry
Waves of light and sound interact to drive electronic and structural changes in a perovskite crystal. At the atomic scale, nothing is ever truly still. Materials that appear perfectly rigid and motionless to the naked eye are in fact swarms of vibrating atoms. This motion is generally random and uncoordinated, but with the right input, the atoms in certain materials will start to move together, vibrating in sync.
These collective vibrations are a form of sound called phonons, and when tuned just right, they can influence a material’s structure and behavior in dramatic and useful ways. Researchers are working to understand and control this effect to optimize material properties and even access hidden phases of matter.
Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are using light to drive phonon activity in a class of materials called metal halide perovskites, whose customizable structures and photosensitivity hold promise for use in next-generation solar cells, advanced sensors and quantum information technologies.
RNA-guided transposon mechanics show use of figure-eight intermediate and direct-transfer route
IS110 transposons are a large, diverse family of bacterial insertion sequences (IS elements)—small, mobile DNA elements that can move from one genomic location to another. They have recently attracted broad interest due to the finding that some of these transposons use a bridge RNA (bRNA) to recognize both donor DNA and target DNA.
Upon this discovery, researchers hoped that bRNA-guided transposon systems could offer a genome-editing strategy distinct from classical CRISPR-Cas nucleases and thereby enable programmable DNA integration. However, it remained unclear how IS110 elements insert donor DNA into target sites and whether these elements rely on one or multiple reaction pathways.
Now, a new study led by Xue Chaoyou from the Tianjin Institute of Industrial Biotechnology of the Chinese Academy of Sciences, in collaboration with Lou Huiqiang at China Agricultural University and RAO Shuquan from the Chinese Academy of Medical Sciences, answers these questions by showing that RNA-guided IS110 transposons use two mechanistically distinct pathways to mobilize DNA.
Magnetic field helps binary star systems form, new simulations indicate
New simulations show that interactions with a magnetic field can work to decrease the distance between still forming binary protostars. These results can help explain the characteristics of the binary star systems observed in the Milky Way. The results can also be extrapolated to binary black holes, giving insights into how supermassive black holes evolve.
The work is published in the journal Monthly Notices of the Royal Astronomical Society.
Stars form from clouds of interstellar gas that collapse into dense regions known as molecular cloud cores. Multiple stars form close together simultaneously, and in some cases two stars will become gravitationally bound to each other, forming a binary star system.