In May 2024, auroras were observed at unusually low latitudes across the globe, lighting up skies that rarely see such displays. Inside Earth’s magnetosphere, the region of space surrounding our planet and dominated by its intrinsic magnetic field, something significant was finally being observed. It started with a large sunspot firing a rapid series of powerful solar eruptions. Clouds of magnetized plasma merged as they traveled through space and impacted Earth's magnetosphere. No geomagnetic storm this powerful had ever been measured in the Earth’s ring current region, a belt of charged particles in space near our planet. Two sources of ring current ions are known: solar wind and Earth's ionosphere, the electrically charged upper layer of the atmosphere. For decades, scientists have debated how much each source contributes to the ring current. During most storms, both contribute. However, during a storm driven by a dense solar wind, some scientists expected solar wind ions to continue to play a notable role. Yet the first direct measurements of ring current composition from a super geomagnetic storm revealed that solar wind ion contributions were minimal, and the level of Earth-origin ion dominance had never been observed before. The findings, published in Science Advances, suggest that understanding how much Earth's ionosphere contributes to the ring current may be essential to accurately predict the severity of super geomagnetic storms. The dominance of ionospheric ions, which are far heavier than solar wind particles, may have intensified the magnetic disturbance and concentrated the ring current peak unusually close to Earth. The researchers also make a case for a proposed Japanese multi-satellite mission to understand exactly how ion supply processes work.

In contrast to the misconception that breastfed babies sleep less as breastmilk is easily digested, a new study of 82,918 infants found that children who received breast milk during the first six months of life were less likely to experience short sleep duration at one year of age than those who were exclusively fed formula. Using data from the Japan Environment and Children’s Study, the researchers proposed biological mechanisms that may help explain this association.

Accounting for atmospheric degradation of levoglucosan is essential for accurate identification of biomass burning sources in tropical regions, but as much as 88% of levoglucosan may be lost before measurement. After correcting for this atmospheric loss, the researchers identified urban domestic use of fuels, rather than agricultural burning, as the dominant source of PM_2.5 in Ho Chi Minh City, Vietnam. 

An Osaka Metropolitan University researcher evaluated Japan’s Location Optimization Plan, a national compact city policy, using a quasi-experimental analysis across 1,595 SMCs from 2008 to 2022. The findings caution against one-size-fits-all compact city policies and suggest that small cities may need more selective, context-sensitive approaches, including smart-decline principles.

A research team at Saitama University has used first-principles quantum-mechanical calculations to clarify how various atomic-scale defects control the electronic structure, excitonic behavior, and optical properties of carbon quantum dots. The findings provide atomistic design guidelines for environmentally friendly carbon nanomaterials with potential applications in fluorescence sensing, photocatalysis, bioimaging, photothermal therapy, and optoelectronic devices.

The double-bond character of phosphates in solid and liquid phases was investigated using the P=O π* peaks in oxygen K-edge X-ray absorption spectroscopy (XAS). In the solid phase, the double-bond character of phosphates increased with increasing negative charge; NaH₂PO₄ exhibited weak P=O π* peaks, whereas Na₃PO₄ exhibited prominent P=O π* peaks. In an aqueous Na₃PO₄ solution, the double-bond character was reduced owing to interactions between phosphate and Na⁺ as well as the formation of hydration structures. These findings provide insights into the influence of chemical environment on the electronic structure and reactivity of phosphate compounds involved in various biological processes such as adenosine triphosphate hydrolysis.

Hiroshima University researchers use the previous 20 years of data to project what the currently implemented treatment and management strategy does for the HBV and HCV cases in 2050.

Cancers caused by mutations in the KRAS gene are challenging to treat, and current KRAS inhibitor therapies can leave behind reversible drug-tolerant persister (DTP) cells that survive therapy, contributing to tumor regrowth and relapse. Researchers from Chiba University found that these surviving cells adapt by reshaping their metabolism. By targeting these metabolic adaptations, the team succeeded in reducing the survival of DTP cells. The findings may help develop therapies to reduce relapse in KRAS-mutant cancers.

In group decision-making, discussing from an overarching perspective is often difficult. Imagining oneself from a third-person perspective during group discussions may significantly change how people communicate and make decisions together. In this context, researchers investigated the effect of third-person perspective and first-person perspective in a virtual environment on group decision-making. They found that participants using a third-person perspective in virtual reality showed better consensus, improved understanding of others’ opinions, and reduced conflict.