编译|李言
物理Physics
Characterizing transport in a quantum gas by measuring Drude weights
通过测量德鲁德权重以表征量子气体中的输运特性
▲ 作者：Philipp Schüttelkopf, Mohammadamin Tajik et al.
▲链接：
https://www.science.org/doi/10.1126/science.ads8327
▲摘要：
输运特性决定了材料是绝缘体、金属还是超导体。一个基本参数是德鲁德权重——它量化了电荷载流子的弹道输运。
在这项研究中，研究者测量了受限于一维的相互作用玻色原子超冷气体的德鲁德权重，通过施加恒定力以及连接两个处于不同平衡态的子系来诱导原子流和能量流，进而表征其输运特性。
他们证明了即使在存在相互作用和有限温度的情况下，系统仍可实现无耗散输运，这意味着对应最低阶流体动力学的守恒量具有弹道传播特性。这种方法为表征强关联量子物质的输运特性提供了一个稳健且明晰的框架，适用于理论尚不完善的物理区域。
▲ Abstract：
Transport properties define materials as insulators, metals, or superconductors. A fundamental parameter is the Drude weight, which quantifies the ballistic transport of charge carriers. In this study, we measured the Drude weights of an ultracold gas of interacting bosonic atoms confined to one dimension, characterizing atomic and energy currents induced by applying a constant force and by joining two subsystems prepared in different equilibrium states. We demonstrate dissipationless transport, even in the presence of interactions and finite temperature, signifying ballistic propagation of conserved quantities corresponding to lowest-order hydrodynamics. Our approach provides a robust and transparent framework for characterizing transport in strongly correlated quantum matter, applicable in regimes where theory remains incomplete.
天文学Astronomy
A sudden change and recovery in the magnetic environment around a repeating fast radio burst
快速射电暴周围磁环境的一次突变与恢复
▲ 作者：Y. Li, S. B. Zhang et al.
▲链接：
https://www.science.org/doi/10.1126/science.adq3225
▲摘要：
快速射电暴（FRBs）是源自河外星系的毫秒级射电暂现现象。部分重复暴因其磁离子环境变化而表现出法拉第旋转量（RM）的波动。研究者报告了重复暴 FRB 20220529（位于红移0.18的盘状星系）的磁离子环境变化。
在前17个月的观测中，其RM中值为17弧度每平方米（rad m?2），离散范围约101 rad m?2。至2023年12月，RM跃升至1977±84 rad m?2，随后在两周内逐渐恢复至典型水平。
这种RM的突变表明，一个致密的磁化等离子体团块穿过了视线方向。研究者探讨了可能的解释，包括伴星的日冕物质抛射、高等离子体湍流或双星轨道运动等机制。
▲ Abstract：
Fast radio bursts (FRBs) are millisecond-duration radio transients from extragalactic sources. Some repeating FRBs exhibit variations in their Faraday rotation measure (RM) due to changes in their magneto-ionic environment. We report magneto-ionic variations of FRB 20220529, a repeating FRB from a disk galaxy at redshift 0.18. For the first 17 months of observations, the RM had a median of 17 radians per square meter (rad m?2) and a scatter of 101 rad m?2. In December 2023, the RM jumped to 1977 ± 84 rad m?2, then gradually returned to typical values within 2 weeks. This sudden RM variation indicates that a dense magnetized clump of plasma passed across the line of sight. We discuss potential explanations, including a coronal mass ejection from a companion star, high plasma turbulence, or binary orbital motion.
医学Medicine
Deep-learning analysis of 3D microarchitectural remodeling in hypertrophic cardiomyopathy
深度学习分析肥厚型心肌病中的三维微结构重塑
▲ 作者：Eric Q. Wei, Martin Beyer et al.
▲链接：
https://www.science.org/doi/10.1126/science.ady6443
▲摘要：
肥厚型心肌病（HCM）是一种以不明原因的心室壁增厚为特征的遗传性心脏病，是全球范围内猝死的主要原因之一。然而，左心室肥厚所对应的心脏组织三维结构机制仍不明确。
研究者开发了CaMVIA-3D，一种深度学习驱动的三维成像与分析流程，用于系统表征心脏微结构。对HCM患者心脏组织的分析显示，不同基因型在心肌细胞体积、形态和细胞外基质体积方面存在显著差异：致病性基因变异表现为更明显的同心性细胞肥厚与排列紊乱，而基因变异阴性病例则以纤维化为主。
通过对猪HCM模型的纵向动态分析，研究者发现纤维化出现于心肌细胞肥厚之前。通过整合转录组学与形态学变化，研究者进一步识别出与细胞及细胞外基质重构相关的关键基因。这些发现明确了HCM中基因型特异性的微结构差异，为改进诊断方法和开发靶向治疗提供了新思路。
▲ Abstract：
Hypertrophic cardiomyopathy (HCM), a genetic heart disease defined by unexplained cardiac wall thickening, is a leading cause of sudden death worldwide. However, the three-dimensional organization of cardiac tissue underlying left ventricular hypertrophy remains poorly understood. We developed CaMVIA-3D, a deep-learning volumetric imaging and analysis pipeline to characterize cardiac microarchitecture. Analysis of tissues from HCM hearts revealed genotype-specific differences in cardiomyocyte volume, morphology, and extracellular volume, with pathogenic variants exhibiting greater concentric cellular hypertrophy and disarray and variant-negative cases showing predominant fibrosis. Longitudinal profiling of a pig HCM model revealed early-onset fibrosis preceding cardiomyocyte hypertrophy. Integrating transcriptomic and morphologic changes, we identified genes associated with cellular and extracellular remodeling. These findings define genotype-specific microstructural differences in HCM, offering insights to improve diagnostics and targeted therapies.
古生物学Paleontology
A diminutive tyrannosaur lived alongside Tyrannosaurus rex
一种与霸王龙共存的小型暴龙
▲ 作者：Christopher T. Griffin, Jeb Bugos et al.
▲链接：
https://www.science.org/doi/10.1126/science.adx8706
▲摘要：
矮暴龙（Nanotyrannus lancensis）究竟是一个独立的物种，还是未成年的霸王龙（Tyrannosaurus rex），这一争议已持续数十年。
矮暴龙的正模标本（编号 CMNH 7541）仅包括一个孤立的头骨及角鳃骨，但形态类似矮暴龙的个体其四肢骨组织学分析表明这些个体实为未成熟的霸王龙，暗示该正模标本可能同样处于幼年阶段。
这项研究证实，角鳃骨（亦称“舌骨”）组织学在现存及已灭绝的主龙类个体发育评估中具有重要价值。对矮暴龙正模标本角鳃骨的组织学分析显示，该个体已接近或已达到骨骼成熟阶段，这表明其在分类学上应独立于同时代的霸王龙。
这一发现进一步说明，在白垩纪—古近纪大灭绝事件前夕，地狱溪组及其同年代生态系统曾支持着多样化的掠食性恐龙类群共存。
▲ Abstract：
Whether Nanotyrannus lancensis represents a distinct taxon or an immature Tyrannosaurus rex is a decades-long controversy. The N. lancensis holotype (CMNH 7541) is an isolated skull and ceratobranchials, but limb osteohistology of Nanotyrannus-like individuals implies that these individuals were immature Tyrannosaurus, suggesting that the N. lancensis holotype is also immature. We demonstrate that ceratobranchial (“hyoid”) histology is useful for ontogenetic assessment in extant and extinct archosaurs. The ceratobranchial histology of the N. lancensis holotype indicates that it was nearing or had reached skeletal maturity, suggesting that it is taxonomically distinct from the coeval Tyrannosaurus rex and that Hell Creek (and equivalent) ecosystems supported a diverse assemblage of predatory dinosaurs approaching the Cretaceous-Paleogene extinction.
地球科学Earth Science
Complex mesoscale landscapes beneath Antarctica mapped from space
基于太空测绘揭示的南极冰下复杂中尺度地形
▲ 作者：Helen Ockenden, Robert G. Bingham et al.
▲链接：
https://www.science.org/doi/10.1126/science.ady2532
▲摘要：
被南极冰盖覆盖的地形地貌，对其历史演化研究具有关键意义，并影响着冰盖对气候强迫的响应机制。然而，以往对这一关键界面的认知主要依赖对不规则分布的地球物理勘测数据的插值推演，导致南极冰下地形图存在显著的空间偏差。
由于冰体流经基岩障碍时产生的应力变化会塑造冰面地形，近期获取的高分辨率卫星冰面地图为绘制冰下地貌提供了突破性基础。
研究者通过将冰流物理学原理应用于冰面地图，并结合地球物理观测的冰厚度数据，构建了南极大陆尺度的冰下地形高程图。该结果深化了对中尺度（2至30公里）冰下地貌形态的认识，并揭示了冰下粗糙度与地貌特征的空间分布规律。
▲ Abstract：
he landscape shrouded by the Antarctic Ice Sheet provides important insights into its history and influences the ice response to climate forcing. However, knowledge of this critical boundary has depended on interpolation between irregularly distributed geophysical surveys, creating major spatial biases in maps of Antarctica’s subglacial landscape. As stress changes associated with ice flow over bedrock obstacles produce ice surface topography, recently acquired, high-resolution satellite maps of the ice surface offer a transformative basis for mapping subglacial landforms. We present a continental-scale elevation map of Antarctica’s subglacial topography produced by applying the physics of ice flow to ice surface maps and incorporating geophysical ice thickness observations. Our results enrich understanding of mesoscale (2 to 30 kilometers) subglacial landforms and unmask the spatial distribution of subglacial roughness and geomorphology.
Low-frequency earthquakes track the motion of a captured slab fragment
低频地震追踪受困板块碎片的运动
▲ 作者：David R. Shelly, Amanda M. Thomas et al.
▲链接：
https://www.science.org/doi/10.1126/science.aeb2407
▲摘要：
精确的构造模型对于评估地震灾害和断层相互作用至关重要。然而，圣安德烈亚斯断层与卡斯卡迪亚俯冲带交汇的门多西诺三联点区域构造结构仍不明确。
研究者分析了近期发现的、位于俯冲的戈尔达板块南缘附近的构造性震颤与低频地震（LFEs）带相关的断层滑动。根据潮汐敏感性和P波初动分析，研究者发现低频地震是由倾斜的走滑运动产生的。
这表明一块先前属于法拉隆板块的碎片，现被太平洋板块捕获，正在北美最西缘下方向北移动。这种几何结构有效地延伸了板块界面断层，这对当前关于板块窗口形成的主流解释提出了挑战，并可能在该区域造成尚未被充分认识的地震风险。
▲ Abstract：
Accurate tectonic models are essential for assessing seismic hazard and fault interactions. However, the plate configuration at the complex Mendocino triple junction, where the San Andreas Fault and the Cascadia subduction zone meet, remains uncertain. We analyzed fault slip associated with a recently identified zone of tectonic tremor and low-frequency earthquakes (LFEs) near the southern edge of the subducting Gorda slab. Based on tidal sensitivity and P-wave first motions, we show that the LFEs are generated by dipping, strike-slip motion. This suggests that a former Farallon slab fragment, now captured by the Pacific plate, is translating northward beneath westernmost North America. This geometry effectively extends the slab interface fault, challenging prevailing interpretations of slab window formation and creating a potential unaccounted earthquake hazard in this region.
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