编译 | 李言
Nature, 22 February 2024, Volume 626 Issue 8000
《自然》,2024年2月22日，第626卷，8000期
天文学Astronomy
A lanthanide-rich kilonova in the aftermath of a long gamma-ray burst
长伽马射线爆发后形成的富含镧系元素千新星
▲ 作者：Yu-Han Yang, Eleonora Troja et al.
▲ 链接：
https://www.nature.com/articles/s41586-023-06979-5
▲ 摘要：
在此，我们报告了对同一伽马射线爆发的多波长分析，数据来源包括公开可用的韦布太空望远镜和我们自己的哈勃太空望远镜。
我们模拟了它在爆发后两个月的演化并发现，在这段后期，光球半径的衰退和快速衰减的放热光度（Lbol∝t?2.7±0.4，其中t是时间）支持富镧元素喷射物在冷却时的重组。
▲ Abstract：
Here we report a multi-wavelength analysis, including publicly available James Webb Space Telescope data and our own Hubble Space Telescope data, for the same gamma-ray burst. We model its evolution up to two months after the burst and show that, at these late times, the recession of the photospheric radius and the rapidly decaying bolometric luminosity (Lbol∝t?2.7±0.4, where t is time) support the recombination of lanthanide-rich ejecta as they cool.
物理学Physics
Avoiding fusion plasma tearing instability with deep reinforcement learning
利用深度强化学习避免聚变等离子体撕裂不稳定
▲ 作者：Jaemin Seo, SangKyeun Kim et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07024-9
▲ 摘要：
在此，我们利用这个动态模型作为强化学习人工智能的训练环境，促进预防自动化的不稳定性。
我们展示了人工智能控制可以降低美国最大的磁聚变设施DIII-D中破坏性撕裂不稳定性的可能性。即使在低安全系数和低扭矩的相对不利条件下，控制器也能在给定阈值下控制撕裂可能性。
特别是，它允许等离子体在时变操作空间内主动跟踪稳定路径，同时保持h模式性能，这是此前传统预编程控制应对的挑战。该控制器为未来在ITER中使用的稳定高性能操作场景的开发铺平了道路。
▲ Abstract：
Here we harness this dynamic model as a training environment for reinforcement-learning artificial intelligence, facilitating automated instability prevention. We demonstrate artificial intelligence control to lower the possibility of disruptive tearing instabilities in DIII-D, the largest magnetic fusion facility in the United States. The controller maintained the tearing likelihood under a given threshold, even under relatively unfavourable conditions of low safety factor and low torque. In particular, it allowed the plasma to actively track the stable path within the time-varying operational space while maintaining H-mode performance, which was challenging with traditional preprogrammed control. This controller paves the path to developing stable high-performance operational scenarios for future use in ITER.
化学Chemistry
Signatures of a surface spin–orbital chiral metal
表面自旋轨道手性金属的特征
▲ 作者：Federico Mazzola, Wojciech Brzezicki et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07033-8
▲ 摘要：
在此，我们构建了对称破缺手性基态的理论矿建，并提出了一种基于圆偏振、自旋选择以及角分辨光电子能谱的研究方法。
我们使用原型量子材料Sr2RuO4并揭示了其光谱特征，尽管这些特征很微妙，但可以与材料表面自旋轨道手性电流的形成协调关系。当我们阐明这些手性体系时，我们的发现为更深入地理解有序现象和非常规磁性铺平了道路。
▲ Abstract：
Here we develop a theory for symmetry-broken chiral ground states and propose a methodology based on circularly polarized, spin-selective, angular-resolved photoelectron spectroscopy to study them. We use the archetypal quantum material Sr2RuO4 and reveal spectroscopic signatures that, despite being subtle, can be reconciled with the formation of spin–orbital chiral currents at the surface of the material. As we shed light on these chiral regimes, our findings pave the way for a deeper understanding of ordering phenomena and unconventional magnetism.
材料科学Material Science
A 3D nanoscale optical disk memory with petabit capacity
具有pb级的三维纳米级光盘存储器
▲ 作者：Miao Zhao, Jing Wen et al.
▲ 链接：
https://www.nature.com/articles/s41586-023-06980-y
▲ 摘要：
在此，我们通过将平面记录架构扩展到数百层的三维空间，同时打破记录点的光学衍射极限屏障，将光存储容量提高到pb级。我们开发了一种基于掺有聚集致发射染料的光刻胶薄膜的光学记录介质，该介质可以被飞秒激光束光激发。
该薄膜具有高透明度和均匀性，聚集诱导发射现象提供了储存机制。它也可以被另一个失活光束抑制，从而产生一个具有超分辨率刻度的记录点。这项技术使得通过将纳米级磁盘堆叠成阵列来实现exabit级存储成为可能，这对空间有限的大数据中心至关重要。
▲ Abstract：
Here, to address these issues, we increase the capacity of ODS to the petabit level by extending the planar recording architecture to three dimensions with hundreds of layers, meanwhile breaking the optical diffraction limit barrier of the recorded spots. We develop an optical recording medium based on a photoresist film doped with aggregation-induced emission dye, which can be optically stimulated by femtosecond laser beams. This film is highly transparent and uniform, and the aggregation-induced emission phenomenon provides the storage mechanism. It can also be inhibited by another deactivating beam, resulting in a recording spot with a super-resolution scale. This technology makes it possible to achieve exabit-level storage by stacking nanoscale disks into arrays, which is essential in big data centres with limited space.
地球科学Earth Science
Progressive unanchoring of Antarctic ice shelves since 1973
自1973年以来南极冰架的逐步解锚
▲ 作者：Bertie W. J. Miles & Robert G. Bingham
▲ 链接：
https://www.nature.com/articles/s41586-024-07049-0
▲ 摘要：
在此，我们测量了1973—1989年、1989—2000年和2000—2022年三个时期的钉点变化，从而推断出1973—1989年冰架厚度的变化。我们发现，在1973年至1989年间，只有一小部分位于阿蒙森海海湾和威尔克斯陆地海岸线的局部冰架变薄。冰架变薄在20世纪90年代和21世纪头十年迅速蔓延，其最显著特征是钉点的比例减少。
从1973年到1989年，只有15%的钉点下降，然后1989年到2000年增加到25%，2000年到2022年增加到37%。如果这一趋势继续下去，将进一步减少冰架的支撑潜力，增加冰的流量，并加速南极洲对海平面上升的贡献。
▲ Abstract：
Here we measure pinning-point change over three epochs spanning the periods 1973-1989, 1989-2000 and 2000-2022, and thus by proxy infer changes to ice-shelf thickness back to 1973-1989. We show that only small localized pockets of ice shelves were thinning between 1973 and 1989, located primarily in the Amundsen Sea Embayment and the Wilkes Land coastline. Ice-shelf thinning spreads rapidly into the 1990s and 2000s and is best characterized by the proportion of pinning points reducing in extent. Only 15% of pinning points reduced from 1973 to 1989, before increasing to 25% from 1989 to 2000 and 37% from 2000 to 2022. A continuation of this trend would further reduce the buttressing potential of ice shelves, enhancing ice discharge and accelerating the contribution of Antarctica to sea-level rise.
医学Medince
Smoking changes adaptive immunity with persistent effects
吸烟会改变适应性免疫并产生持久的影响
▲ 作者：Violaine Saint-André, Bruno Charbit et al.
▲ 链接：
https://www.nature.com/articles/s41586-023-06968-8
▲ 摘要：
在此，我们调查了136个变量，并确定吸烟、巨细胞病毒潜伏感染和体重指数是细胞因子反应变异性的主要影响因素，其影响程度与年龄、性别和遗传有关。
我们发现吸烟会影响先天免疫反应和适应性免疫反应。值得注意的是，它对先天反应的影响在戒烟后很快消失，并与CEACAM6的血浆水平特异性相关，而其对适应性免疫反应的影响在个体戒烟后仍会持续很长时间，并与表观遗传记忆有关。
过去的研究曾认为吸烟对细胞因子反应的影响与特定信号反式激活因子和代谢调节因子的DNA甲基化有关，这一点得到了我们的支持。我们的研究结果确定了与细胞因子分泌变异性相关的三个新变量，并揭示了吸烟在免疫反应的短期和长期调节中的作用。
▲ Abstract：
Here we investigated 136 variables and identified smoking, cytomegalovirus latent infection and body mass index as major contributors to variability in cytokine response, with effects of comparable magnitudes with age, sex and genetics. We find that smoking influences both innate and adaptive immune responses. Notably, its effect on innate responses is quickly lost after smoking cessation and is specifically associated with plasma levels of CEACAM6, whereas its effect on adaptive responses persists long after individuals quit smoking and is associated with epigenetic memory. This is supported by the association of the past smoking effect on cytokine responses with DNA methylation at specific signal trans-activators and regulators of metabolism. Our findings identify three novel variables associated with cytokine secretion variability and reveal roles for smoking in the short- and long-term regulation of immune responses.
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