編譯 | 李言
Nature, 22 February 2024, Volume 626 Issue 8000
《自然》,2024年2月22日，第626卷，8000期
天文學Astronomy
A lanthanide-rich kilonova in the aftermath of a long gamma-ray burst
長伽馬射線爆發后形成的富含鑭系元素千新星
▲ 作者：Yu-Han Yang, Eleonora Troja et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06979-5
▲ 摘要：
在此，我們報告了對同一伽馬射線爆發的多波長分析，數據來源包括公開可用的韋布太空望遠鏡和我們自己的哈勃太空望遠鏡。
我們模擬了它在爆發后兩個月的演化并發現，在這段后期，光球半徑的衰退和快速衰減的放熱光度（Lbol∝t?2.7±0.4，其中t是時間）支持富鑭元素噴射物在冷卻時的重組。
▲ 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.
物理學Physics
Avoiding fusion plasma tearing instability with deep reinforcement learning
利用深度強化學習避免聚變等離子體撕裂不穩定
▲ 作者：Jaemin Seo, SangKyeun Kim et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-024-07024-9
▲ 摘要：
在此，我們利用這個動態模型作為強化學習人工智能的訓練環境，促進預防自動化的不穩定性。
我們展示了人工智能控制可以降低美國最大的磁聚變設施DIII-D中破壞性撕裂不穩定性的可能性。即使在低安全系數和低扭矩的相對不利條件下，控制器也能在給定閾值下控制撕裂可能性。
特別是，它允許等離子體在時變操作空間內主動跟蹤穩定路徑，同時保持h模式性能，這是此前傳統預編程控制應對的挑戰。該控制器為未來在ITER中使用的穩定高性能操作場景的開發鋪平了道路。
▲ 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.
化學Chemistry
Signatures of a surface spin–orbital chiral metal
表面自旋軌道手性金屬的特征
▲ 作者：Federico Mazzola, Wojciech Brzezicki et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-024-07033-8
▲ 摘要：
在此，我們構建了對稱破缺手性基態的理論礦建，并提出了一種基于圓偏振、自旋選擇以及角分辨光電子能譜的研究方法。
我們使用原型量子材料Sr2RuO4并揭示了其光譜特征，盡管這些特征很微妙，但可以與材料表面自旋軌道手性電流的形成協調關系。當我們闡明這些手性體系時，我們的發現為更深入地理解有序現象和非常規磁性鋪平了道路。
▲ 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.
材料科學Material Science
A 3D nanoscale optical disk memory with petabit capacity
具有pb級的三維納米級光盤存儲器
▲ 作者：Miao Zhao, Jing Wen et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06980-y
▲ 摘要：
在此，我們通過將平面記錄架構擴展到數百層的三維空間，同時打破記錄點的光學衍射極限屏障，將光存儲容量提高到pb級。我們開發了一種基于摻有聚集致發射染料的光刻膠薄膜的光學記錄介質，該介質可以被飛秒激光束光激發。
該薄膜具有高透明度和均勻性，聚集誘導發射現象提供了儲存機制。它也可以被另一個失活光束抑制，從而產生一個具有超分辨率刻度的記錄點。這項技術使得通過將納米級磁盤堆疊成陣列來實現exabit級存儲成為可能，這對空間有限的大數據中心至關重要。
▲ 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.
地球科學Earth Science
Progressive unanchoring of Antarctic ice shelves since 1973
自1973年以來南極冰架的逐步解錨
▲ 作者：Bertie W. J. Miles & Robert G. Bingham
▲ 鏈接：
https://www.nature.com/articles/s41586-024-07049-0
▲ 摘要：
在此，我們測量了1973—1989年、1989—2000年和2000—2022年三個時期的釘點變化，從而推斷出1973—1989年冰架厚度的變化。我們發現，在1973年至1989年間，只有一小部分位于阿蒙森海海灣和威爾克斯陸地海岸線的局部冰架變薄。冰架變薄在20世紀90年代和21世紀頭十年迅速蔓延，其最顯著特征是釘點的比例減少。
從1973年到1989年，只有15%的釘點下降，然后1989年到2000年增加到25%，2000年到2022年增加到37%。如果這一趨勢繼續下去，將進一步減少冰架的支撐潛力，增加冰的流量，并加速南極洲對海平面上升的貢獻。
▲ 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.
醫學Medince
Smoking changes adaptive immunity with persistent effects
吸煙會改變適應性免疫并產生持久的影響
▲ 作者：Violaine Saint-André, Bruno Charbit et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06968-8
▲ 摘要：
在此，我們調查了136個變量，并確定吸煙、巨細胞病毒潛伏感染和體重指數是細胞因子反應變異性的主要影響因素，其影響程度與年齡、性別和遺傳有關。
我們發現吸煙會影響先天免疫反應和適應性免疫反應。值得注意的是，它對先天反應的影響在戒煙后很快消失，并與CEACAM6的血漿水平特異性相關，而其對適應性免疫反應的影響在個體戒煙后仍會持續很長時間，并與表觀遺傳記憶有關。
過去的研究曾認為吸煙對細胞因子反應的影響與特定信號反式激活因子和代謝調節因子的DNA甲基化有關，這一點得到了我們的支持。我們的研究結果確定了與細胞因子分泌變異性相關的三個新變量，并揭示了吸煙在免疫反應的短期和長期調節中的作用。
▲ 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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