《科學》（20240412出版）一周論文導讀

天體物理學Astrophysics

A magnetic massive star has experienced a stellar merger

經歷了恒星合并的一顆大質量磁性恒星

▲ 作者：A. J. FROST, H. SANA et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adg7700

▲ 摘要：

我們使用多歷元干涉和光譜觀測來描述HD 148937，這是一個由兩顆大質量恒星組成的雙星系統。我們發現其中只有一顆恒星具有磁性，且它看起來比伴星更年輕。該系統的特性和周圍的雙極星云可以用兩顆恒星合并（在先前的三重系統中）產生磁性大質量恒星的模型來重現。

我們的結果提供了觀測證據以證明至少在一些大質量恒星中，磁場是通過恒星合并形成的。

▲ Abstract：

We used multi-epoch interferometric and spectroscopic observations to characterize HD 148937, a binary system of two massive stars. We found that only one star is magnetic and that it appears younger than its companion. The system properties and a surrounding bipolar nebula can be reproduced with a model in which two stars merged (in a previous triple system) to produce the magnetic massive star. Our results provide observational evidence that magnetic fields form in at least some massive stars through stellar mergers.

化學Chemistry

Thin adhesive oil films lead to anomalously stable mixtures of water in oil

薄粘接油膜使得水的混合物在油里異常穩定

▲ 作者：CLAIRE NANNETTE, JEAN BAUDRY et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adj6728

▲ 摘要：

油和水的混合，只能通過將一種液體的液滴分散到另一種液體中才能實現。當兩個液滴相互靠近時，將它們分開的薄膜總是變得不穩定，導致液滴聚在一起。避免這種不穩定性的唯一已知方法是通過添加第三種成分，通常是表面活性劑，使得薄膜穩定在其平衡厚度上。

我們觀察到，通過一層薄的油流體膜將兩個水滴分開，會導致水滴之間的粘附相互作用。此外，在不使用任何表面活性劑或溶劑的情況下，這種相互作用可以防止它們聚結的時間長達數周。

▲ Abstract：

Oil and water can only be mixed by dispersing droplets of one fluid in the other. When two droplets approach one another, the thin film that separates them invariably becomes unstable, causing the droplets to coalesce. The only known way to avoid this instability is through addition of a third component, typically a surfactant, which stabilizes the thin film at its equilibrium thickness. We report the observation that a thin fluid film of oil separating two water droplets can lead to an adhesive interaction between the droplets. Moreover, this interaction prevents their coalescence over timescales of several weeks, without the use of any surfactant or solvent.

物理學Physics

Realization of an atomic quantum Hall system in four dimensions

四維空間中原子量子霍爾系統的實現

▲ 作者：JEAN-BAPTISTE BOUHIRON, AURéLIEN FABRE et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adf8459

▲ 摘要：

我們報告一個四維演化的原子量子霍爾系統的實現，其中兩個空間維度和兩個合成維度編碼在鏑原子的大自旋中。通過對非線性電磁響應的全面表征，我們測量了接地帶的非平凡拓撲指數，并觀察了相關的各向異性超邊緣模式。

與D≤3的平面軌道不同，我們還激發了非平面回旋加速器運動。我們的研究或使四維空間中強相關的拓撲液體研究成為可能，歸納分數量子霍爾態。

▲ Abstract：

We report the realization of an atomic quantum Hall system evolving in four dimensions (4D), with two spatial dimensions and two synthetic ones encoded in the large spin of dysprosium atoms. We measure the nontrivial topological index of the ground band through a full characterization of the nonlinear electromagnetic response and observe the associated anisotropic hyperedge modes. We also excite nonplanar cyclotron motion, in contrast to the planar orbits in D ≤ 3. Our work may enable the investigation of strongly correlated topological liquids in 4D, generalizing fractional quantum Hall states.

地球科學Earth Science

Size, distribution, and vulnerability of the global soil inorganic carbon

全球土壤無機碳儲量的規模、分布和脆弱性

▲ 作者：YUANYUAN HUANG , XIAODONG SONG et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adi7918

▲ 摘要：

通過編譯223593個實地測量數據并開發機器學習模型，我們認為，全球土壤在地表2米深度上以土壤無機碳形式儲存了2305±636（±1 SD）億噸碳。在未來的情景中，與陸地生態系統氮添加相關的土壤酸化將在未來30年減少全球土壤無機碳高達230億噸的碳，其中印度和中國受影響最大。

我們對當前陸地—水的碳儲量和內陸水碳酸鹽化學的綜合研究表明，每年至少有1.13±3.3億噸無機碳通過土壤流失到內陸水域，對大氣和水圈碳動態產生的影響巨大卻被忽視了。

▲ Abstract：

By compiling 223,593 field-based measurements and developing machine-learning models, we report that global soils store 2305 ± 636 (±1 SD) billion tonnes of carbon as SIC over the top 2-meter depth. Under future scenarios, soil acidification associated with nitrogen additions to terrestrial ecosystems will reduce global SIC (0.3 meters) up to 23 billion tonnes of carbon over the next 30 years, with India and China being the most affected. Our synthesis of present-day land-water carbon inventories and inland-water carbonate chemistry reveals that at least 1.13 ± 0.33 billion tonnes of inorganic carbon is lost to inland-waters through soils annually, resulting in large but overlooked impacts on atmospheric and hydrospheric carbon dynamics.

生物學Biology

Two inhibitory neuronal classes govern acquisition and recall of spinal sensorimotor adaptation

兩類抑制神經元控制脊髓感覺運動適應的習得和回憶

▲ 作者：SIMON LAVAUD, CHARLOTTE BICHARA et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adf6801

▲ 摘要：

通過一個簡單的條件反射范例，我們發現背側抑制神經元通過調節一組特定體感信息的傳遞來增強與肢體位置相關的條件反射線索的顯著性，從而適應保護性肢體退縮行為。

相比之下，維持先前獲得的運動適應需要腹側抑制閏紹細胞。操縱閏紹細胞并不影響適應性本身，但可以靈活地改變適應性行為的表達。這些發現確定了一個涉及兩種不同脊髓抑制性神經元群的回路基礎，能使持久的感覺運動適應獨立于大腦。

▲ Abstract：

Using a simple conditioning paradigm, we found that dorsal inhibitory neurons are indispensable for adapting protective limb-withdrawal behavior by regulating the transmission of a specific set of somatosensory information to enhance the saliency of conditioning cues associated with limb position. By contrast, maintaining previously acquired motor adaptation required the ventral inhibitory Renshaw cells. Manipulating Renshaw cells does not affect the adaptation itself but flexibly alters the expression of adaptive behavior. These findings identify a circuit basis involving two distinct populations of spinal inhibitory neurons, which enables lasting sensorimotor adaptation independently from the brain.

Nitrogen-fixing organelle in a marine alga

海藻中的固氮細胞器

▲ 作者：TYLER H. COALE, VALENTINA LOCONTE et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adk1075

▲ 摘要：

共生相互作用是調節真核生物碳和能量代謝的葉綠體和線粒體細胞器進化的關鍵。在這里，我們表明地中海候選藍藻（UCYN-A）已經緊密地整合到藻類細胞結構和細胞器分裂中，并且它進口由藻類基因組編碼的蛋白質。

這些都是細胞器的特征，表明UCYN-A已經進化到超越了內共生，并作為早期進化階段的氮固定細胞器或“硝化質體”發揮作用。

▲ Abstract：

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or “nitroplast.”