Sharks can hear – and react to – underwater sounds from nearly 250 feet away, according to a new study that provides the first quantified evidence of long-distance sound detection in free-swimming sharks. Researchers found that blacktip sharks rapidly changed course when they detected low-frequency sounds, revealing that they not only hear distant sounds but also determine where they are coming from. The findings also show sharks are more sensitive to lower-frequency sounds, providing new insight into how these ancient predators sense their underwater world.

Alaska's orange, rusted rivers from melting permafrost are even more acidic than water leached from metal mines — an increasingly common mark of climate change, finds a UC Davis study.

Superconductors can carry electrical current without resistance, but only up to a maximum value known as the critical current. The critical current is a crucial figure of merit for applications, and materials science has been long focused on increasing this limit. Researchers at the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) have now shown that, in type-II superconductors, this conventional limit can be exceeded when the current is applied for only a few picoseconds. On these ultrashort timescales, the researchers were able to access a much higher, intrinsic limit known as the depairing current. The work has now been published in Nature Physics.

Circularly polarized light (CPL) carries spin angular momentum information and holds great promise for magnetic recording, spin optical communication, biological sensing and quantum computation. Conventional CPL detectors rely heavily on bulky and complex external optical components, which restrict device integration and miniaturization. Chiral organic semiconductors possessing an intrinsic capability for direct CPL discrimination, have emerged as promising candidates for CPL detectors. However, their development faces an intrinsic trade-off between charge carrier mobility and absorption dissymmetry factor.

Encouragingly, tremendous efforts have been devoted to resolving this contradiction, contributing to the development of a series of high-performance chiral organic semiconductors and thereby CPL detectors. Now, writing in Science Bulletin, researchers at the Institute of Chemistry, Chinese Academy of Sciences, systematically review representative progress of chiral organic semiconductors with a particular emphasis on the planarity-helicity dilemma and spectral tailoring. The review further highlights advances in CPL detectors and emerging applications, and discusses key challenges and future opportunities toward high-performance, miniaturized, and integrated CPL detection technologies.

EHU researchers Urko Petralanda and Luis Elcoro, in collaboration with DIPC researchers, report the article titled “Two-dimensional topological quantum chemistry and catalog of topological materials”, published in Science, that maps the electronic properties of nearly 9,000 single-layer materials and identifies more than 4,000 topologically non-trivial or obstructed entries.

Electronic materials can change their behavior when molecules interact with surrounding ions, but controlling these effects remains challenging. Now, researchers from Ritsumeikan University, Japan, have developed π-electronic cations whose molecular shape and electronic properties are controlled by counteranions. The ion-dependent changes modulate photoinduced electron transfer, pressure-responsive photophysical behavior, and solid-state assembly, offering design principles for smart materials, molecular switches, sensors, and tunable charge-transport technologies. These findings could accelerate development of next-generation responsive electronic devices.

Researchers have realized nonreciprocal dynamic degeneracy splitting in a gyromagnetic non-Hermitian photonic crystal. By engineering different lifetimes for opposite momentum channels at the same real frequency, the system turns loss into a directional selector, enabling momentum-selective bulk transmission and directional imaging.