SOCIAL SCIENCES
Bronze Age carnelian bead from Sanxingdui pits, southwestern China. Image credit: Hui Ren (Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China).
Origins of carnelian in Bronze Age China
In Late Bronze Age China, carnelian beads became widely associated with high-status burials during the Western Zhou Period, around 1000–800 BCE. Although the beads have been attributed to long-distance exchange with the Eurasian interior, the geological origin of the carnelian is not well-understood. Meiting Yan, Jiancheng Liu et al. analyzed the trace elemental compositions of 11 carnelian beads from the Sanxingdui pits in the Sichuan Basin of southwestern China, dated to around 1200–1000 BCE. The authors compared the results with a geochemical database of 300 samples collected from 27 carnelian sources across Asia. Based on analysis of 20 elements, the authors identified compositional differences between carnelian source regions with more than 90% accuracy. Seven Sanxingdui beads were assigned to the Yanshan orogenic province, three beads to the broader Central Asian Orogenic Belt, and one bead to an unknown source. The findings suggest that the raw materials for the carnelian beads originated more than 1,000 kilometers to the north of Sanxingdui. Analysis of contemporary carnelian beads from Gansu, Shaanxi, and Beijing indicated similar northern origins. According to the authors, the findings illuminate long-distance trade between the Bronze Age Sichuan Basin and Northern China, possibly including the Mongolian Plateau. — M.H.
BIOPHYSICS AND COMPUTATIONAL BIOLOGY
Babesia microti (purple) preparing to invade an RBC (red) coated in fibrin (yellow).
Parasite drives movement in infected red blood cells
The protozoan parasite Babesia microti is the primary causative agent of human babesiosis, a disease that can cause flu-like symptoms and anemia. How B. microti moves within infected vertebrate red blood cells (RBCs) after the parasite enters the bloodstream, typically through tick bites, is not well-understood. Chao Li et al. report that a subset of RBCs from mice infected with B. microti acquire the ability to move. RBCs are not typically motile, given that they lack any cellular structures associated with active movement. Using live cell tracking, the authors observed clear directional movement in around 1% of infected RBCs. The motile RBCs achieved velocities of around 2 micrometers per minute in whole blood, comparable with the velocities of macrophage immune cells, at around 1–3 micrometers per minute. The authors observed the parasites moving at the leading edge of infected RBC membranes, which exhibited significant deformations, compared with uninfected RBCs. The RBCs did not move further after the parasites exited the cells. Together, the findings suggest that B. microti drives the movement of the infected RBCs by an unidentified mechanism, which may enhance the parasite’s survival, dissemination, or immune evasion. According to the authors, the findings could aid the development of therapeutics for babesiosis. — M.H.
PHYSICS
Electric charges can accelerate without emitting radiation
In classical physics, electric charges, such as electrons, emit electromagnetic radiation whenever they are accelerated by a force. In general, quantum theory also presumes this phenomenon to be true, despite fundamental differences in how the two theories define and interpret acceleration. Expanding on the Aharonov–Bohm effect—the finding that the quantum behavior of systems can change without the application of a force—Y. Aharonov et al. used quantum electrodynamics and hypothetical experiments to show that electric charges can be accelerated quantum mechanically without emitting radiation. The authors describe how an electron, prepared as a superposition of many wave packets, can pass through an array of solenoids in such a way that the individual wave packets accumulate relative phase changes without entering the solenoids. Because the phase changes represent changes in momentum, the particle has accelerated. However, without experiencing the forces that can act only inside the solenoids, the particle cannot radiate. The findings suggest that electromagnetism at quantum scales is more nuanced than accepted and that theories of radiation may need to be reevaluated, according to the authors. — T.J.
AGRICULTURAL SCIENCES
Parasitic braconid wasp larva spinning a cocoon after emerging from the diamondback moth.
How a parasitic wasp castrates its moth host
Parasitic infections can disrupt the reproductive system of hosts through the process of castration. The molecular mechanisms underlying parasitic castration are not well-understood. Hongshuai Gao, Mujuan Guo et al. analyzed how the parasitic braconid wasp Cotesia vestalis triggers castration in the larval testes of its diamondback moth (Plutella xylostella) host. When braconid wasps infect hosts with their eggs, they inject mature particles of bracoviruses, which are domesticated viruses that have permanently integrated into the wasp genome. The bracoviruses integrate into the host genome and express hundreds of virulence genes to support the survival of the wasp offspring. Analysis of Cotesia vestalis bracovirus (CvBV) gene expression patterns in the testes of parasitized larvae identified high expression levels of CvBV_22-9, a protein tyrosine phosphatase. The authors found that CvBV_22-9 targets a cell cycle checkpoint protein to induce cell death, decreasing the size of the host testes and disrupting spermatogenesis. CvBV_22-9 and its functional homologs played a similar role in inducing parasitic castration in fall armyworms (Spodoptera frugiperda) and fruit flies (Drosophila melanogaster), suggesting that the previously unreported pathway may be evolutionarily conserved in insects. According to the authors, the findings could aid the development of biocontrol methods for lepidopteran pests. — M.H.
EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES
Observing stratospheric methane loss
Although methane is a globally important greenhouse gas, key elements of its atmospheric chemistry, notably its oxidation in the stratosphere, have been estimated only using models. Uncovering the rates of methane oxidation in the stratosphere is critical to the global methane budget. Qiang Fu and Cong Dong used data on methane concentration, temperature, and radiative heating from multiple satellites between 2007 and 2010 to generate observational estimates of stratospheric methane loss. The analysis revealed an annual stratospheric methane loss rate of around 49.8 teragrams per year—greater loss than observed in previous model-based estimates. The discrepancy between model-based and observation-based estimates is likely due to bias in methane concentration simulation, as well as in the simulation of temperature and radiative heating. The observational methane loss estimate reduces the imbalance of the bottom-up global methane budget, which was previously 23 teragrams per year according to modeled estimates, to 3 teragrams per year. The latter amount is consistent with the imbalance of 5 teragrams per year that was inferred from top-down estimates. According to the authors, the findings help reconcile global methane budgets and provide insights into the chemistry of methane oxidation by-products. — P.G.
EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES
Lithium-rich pegmatite veins intruded into metamorphic sandy slate in the Jiajika pegmatite ore field in China.
Lithium deposit formation in China’s Jiajika field
Enhanced energy storage underpins new sustainable energy technologies with net-zero carbon emissions. Although the most common strategies depend on lithium (Li) and other critical metals, the geological processes that form pegmatite-type Li deposits remain unclear. Focusing on the Jiajika lithium pegmatite field, which hosts China’s largest pegmatite-type Li deposits, Hai-Zhen Wei et al. explored the roles of extreme differentiation and direct anatexis in Li enrichment during pegmatite formation. The authors used geochemical modeling and isotopic analyses of core samples taken from boreholes drilled into a pegmatite field. The authors suggest a model in which metamorphic dehydration triggers anatexis—a partial melting of metapelitic rocks—that enriches the concentrations of rare metals by two to four times, compared with the upper continental crust. The melt undergoes fractional crystallization of minerals, or differentiation, and filtration, as excess water is squeezed from the magma by overburden pressure. The model, which explains both Li enrichment and the distribution of Li-rich and Li-poor pegmatites at the study site, shows that both anatexis and fractional crystallization were necessary for pegmatite formation in the Jiajika lithium pegmatite field. The findings could aid future explorations of currently undiscovered Li-rich pegmatite deposits, according to the authors. — T.J.
Extinct South American pachyrukhines were mammals with tall teeth thought to be optimized for grazing. They probably looked a lot like these modern maras. Image credit: Shutterstock/Mariano Jedrzejewski.
Tooth structure isn’t always a good indicator of diet in ancient animals
Posted on February 6, 2026
Amy McDermott
Animals with very tall teeth usually eat grass. They need all that enamel for a lifetime of chewing tough plants. At least, that’s been the assumption. Now, the teeth of some extinct South American mammals called pachyrukhines (pack-ee-ru-kines) are challenging that idea as part of a recent study.