Nature, 18 January 2024, VOL 625, ISSUE 7995
《自然》2024年1月18日，第625卷，7995期
天文學Astronomy
Ionized gas extends over 40 kpc in an odd radio circle host galaxy
電離氣體在奇異射電圈宿主星系中延伸超過40kpc
▲ 作者：Alison L. Coil, Serena Perrotta, David S. N. Rupke, Cassandra Lochhaas, Christy A. Tremonti, Aleks Diamond-Stanic, et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06752-8
▲ 摘要：
2021年發現的一類新河外天文源被命名為奇異射電圈（ORCs），是在天空中跨度約1弧分的微弱彌漫射電連續輻射的大環。幾個ORC中心的星系光度紅移為z?0.3-0.6，這意味著射電輻射的物理范圍直徑為幾百kpc，但其來源尚不清楚。
研究組報道了一個ORC的光譜數據，其中包括ORC4中心星系在z = 0.4512處的強[O II]發射追蹤電離氣體。[O II]發射的物理范圍直徑約為40kpc，大于典型早期星系所預期，但比大規模射電連續體發射小一個數量級。
研究還探測到橫跨[O II]星云、大約200千米/秒的速度梯度，以及大約180千米/秒的高速色散。[O II]的等效寬度（大約50?）對于一個靜止星系而言是非常高的。
[O II]發射的形態、運動學和強度與星系附近激波電離氣體的流入一致，之后是一個更大的、向外移動的激波。延伸的光學和射電發射雖然觀測尺度上存在很大差異，但可能是由同一戲劇性事件引發的。
▲ Abstract：
A new class of extragalactic astronomical sources discovered in 2021, named odd radio circles (ORCs), are large rings of faint, diffuse radio continuum emission spanning approximately 1arcminute on the sky. Galaxies at the centres of several ORCs have photometric redshifts of z?0.3–0.6, implying physical scales of several 100 kpc in diameter for the radio emission, the origin of which is unknown. Here we report spectroscopic data on an ORC including strong [O II] emission tracing ionized gas in the central galaxy of ORC4 at z =0.4512. The physical extent of the [O II] emission is approximately 40 kpc in diameter, larger than expected for a typical early-type galaxy but an order of magnitude smaller than the large-scale radio continuum emission. We detect an approximately 200kms1 velocity gradient across the [O II] nebula, as well as a high velocity dispersion of approximately 180 kms1. The [O II] equivalent width (approximately 50?) is extremely high for a quiescent galaxy. The morphology, kinematics and strength of the [OII] emission are consistent with the infall of shock ionized gas near the galaxy, following a larger, outward-moving shock. Both the extended optical and radio emission, although observed on very different scales, may therefore result from the same dramatic event.
人工智能Artificial Intelligence
Solving olympiad geometry without human demonstrations
無需人工演示即可解決奧數幾何問題
▲ 作者：Trieu H. Trinh, Yuhuai Wu, Quoc V. Le, He He & Thang Luong
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06747-5
▲ 摘要：
在奧林匹克競賽中證明數學定理代表了人類水平自動推理的一個顯著里程碑，因為其高難度在世界頂尖大學預科數學人才中是公認的。然而，當前機器學習方法并不適用于大多數數學領域，因為將人類演示翻譯為機器可驗證格式的成本很高。由于幾何具有獨特的翻譯挑戰，從而導致訓練數據嚴重稀缺，因此該問題更加嚴重。
研究組提出了AlphaGeometry，這是一個歐幾里得平面幾何的定理證明器，通過綜合數百萬個不同復雜程度的定理和證明，避開了人類演示的需要。AlphaGeometry是一個神經符號系統，它使用神經語言模型，在該大規模合成數據上從零開始訓練，指導符號演繹引擎在頗具挑戰性的問題中通過無限分支點。
在一組由30個最新奧數問題組成的測試集中，AlphaGeometry解決了25個問題，優于之前只解決10個問題的最佳方法，接近國際數學奧林匹克（IMO）金牌得主的平均水平。值得注意的是，AlphaGeometry生成了人類可讀的證明，在人類專家的評估下解決了IMO 2000年和2015年的所有幾何問題，并在2004年發現了IMO定理轉化的廣義版本。
▲ Abstract：
Proving mathematical theorems at the olympiad level represents a notable milestone in human-level automated reasoning, owing to their reputed difficulty among the world’s best talents in pre-university mathematics. Current machine-learning approaches, however, are not applicable to most mathematical domains owing to the high cost of translating human proofs into machine-verifiable format. The problem is even worse for geometry because of its unique translation challenges, resulting in severe scarcity of training data. We propose AlphaGeometry, a theorem prover for Euclidean plane geometry that sidesteps the need for human demonstrations by synthesizing millions of theorems and proofs across different levels of complexity. AlphaGeometry is a neuro-symbolic system that uses a neural language model, trained from scratch on our large-scale synthetic data, to guide a symbolic deduction engine through infinite branching points in challenging problems. On a test set of 30 latest olympiad-level problems, AlphaGeometry solves 25, outperforming the previous best method that only solves ten problems and approaching the performance of an average International Mathematical Olympiad (IMO) gold medallist. Notably, AlphaGeometry produces human-readable proofs, solves all geometry problems in the IMO 2000 and 2015 under human expert evaluation and discovers a generalized version of a translated IMO theorem in 2004.
材料科學Materials Science
Multifunctional ytterbium oxide buffer for perovskite solar cells
多功能氧化鐿緩沖層助力鈣鈦礦太陽能電池
▲ 作者：Peng Chen, Yun Xiao, Juntao Hu, Shunde Li, Deying Luo, Rui Su, et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06892-x
▲ 摘要：
鈣鈦礦太陽能電池（PSCs）包括夾在幾層不同電荷選擇材料之間的固體鈣鈦礦吸收體，確保器件的單向電流流動和高壓輸出。在p型/本征/n型（p-i-n）PSCs（也稱為反式PSCs）中，電子選擇層和金屬電極之間的“緩沖材料”使電子能夠從電子選擇層流向電極。
此外，這些緩沖材料作為屏障，還可抑制有害物質進入鈣鈦礦吸收劑或降解產物從吸收劑中流出的相互擴散。到目前為止，可蒸發有機分子和原子層沉積的金屬氧化物已獲成功，但每種都有特定的缺陷。
研究組報道了一種化學穩定的氧化鐿（YbOx）多功能緩沖層，通過可擴展熱蒸發沉積制備p-i-n PSCs。在具有窄帶隙鈣鈦礦吸收體的p-i-n PSC中使用這種YbOx緩沖材料，獲得了超過25%的認證功率轉換效率。
研究組還證明了YbOx在從各種類型的鈣鈦礦吸收層中實現高效PSC方面的廣泛適用性，寬帶隙鈣鈦礦吸收層和中帶隙鈣鈦礦吸收層的最優效率分別為20.1%和22.1%。此外，當遭受ISOS-L-3加速老化時，YbOx封裝的器件表現出明顯增強的器件穩定性。
▲ Abstract：
Perovskite solar cells (PSCs) comprise a solid perovskite absorber sandwiched between several layers of different charge-selective materials, ensuring unidirectional current flow and high voltage output of the devices. A ‘buffer material’ between the electron-selective layer and the metal electrode in p-type/intrinsic/n-type (p-i-n) PSCs (also known as inverted PSCs) enables electrons to flow from the electron-selective layer to the electrode. Furthermore, it acts as a barrier inhibiting the inter-diffusion of harmful species into or degradation products out of the perovskite absorber. Thus far, evaporable organic molecules and atomic-layer-deposited metal oxides have been successful, but each has specific imperfections. Here we report a chemically stable and multifunctional buffer material, ytterbium oxide (YbOx), for p-i-n PSCs by scalable thermal evaporation deposition. We used this YbOx buffer in the p-i-n PSCs with a narrow-bandgap perovskite absorber, yielding a certified power conversion efficiency of more than 25%. We also demonstrate the broad applicability of YbOx in enabling highly efficient PSCs from various types of perovskite absorber layer, delivering state-of-the-art efficiencies of 20.1% for the wide-bandgap perovskite absorber and 22.1% for the mid-bandgap perovskite absorber, respectively. Moreover, when subjected to ISOS-L-3 accelerated ageing, encapsulated devices with YbOx exhibit markedly enhanced device stability.
化學Chemistry
Computational prediction of complex cationic rearrangement outcomes
復雜陽離子重排結果的計算預測
▲ 作者：Tomasz Klucznik, Leonidas-Dimitrios Syntrivanis, Sebastian Ba?, Barbara Mikulak-Klucznik, Martyna Moskal, Sara Szymku?, et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06854-3
▲ 摘要：
近年來，人們對計算機輔助有機合成重新產生了興趣。可規劃多步合成途徑的反應和神經網絡算法的使用已徹底改變了該領域，包括生成先進天然產物的實例。這些方法通常基于完整的、文獻推導的“底物到產物”反應規則，無法輕易擴展到反應機理的分析。
研究組展示了配備物理有機化學規則以及量子力學和動力學計算增強的機理步驟的綜合知識庫計算機，可使用反應網絡方法來分析一些最復雜的有機轉化機理：即陽離子重排。該重排是有機化學教科書的基石，并導致分子碳骨架發生顯著變化。
研究組在https://HopCat.allchemy.net/上描述和部署的算法可在幾分鐘內生成可能的機理步驟網絡，跟蹤看似合理的步驟序列并計算預期的產物分布。通過三組實驗驗證了這一算法，即使對訓練有素的化學家而言，這些實驗的分析也頗具挑戰性：（1）預測尾部至頭部萜烯（THT）環化的結果，其中在微小結構細節不同的模塊化前體中編碼了有實質性區別的結果；（2）比較溶液或超分子膠囊中THT環化的結果；（3）分析復雜反應混合物。
該研究結果支持這樣一種愿景，即計算機不再只是操縱已知的反應類型，而是將助力合理化和發現新型且機理復雜的轉化。
▲ Abstract：
Recent years have seen revived interest in computer-assisted organic synthesis. The use of reaction- and neural-network algorithms that can plan multistep synthetic pathways have revolutionized this field, including examples leading to advanced natural products. Such methods typically operate on full, literature-derived ‘substrate(s)-to-product’ reaction rules and cannot be easily extended to the analysis of reaction mechanisms. Here we show that computers equipped with a comprehensive knowledge-base of mechanistic steps augmented by physical-organic chemistry rules, as well as quantum mechanical and kinetic calculations, can use a reaction-network approach to analyse the mechanisms of some of the most complex organic transformations: namely, cationic rearrangements. Such rearrangements are a cornerstone of organic chemistry textbooks and entail notable changes in the molecule’s carbon skeleton. The algorithm we describe and deploy at https://HopCat.allchemy.net/ generates, within minutes, networks of possible mechanistic steps, traces plausible step sequences and calculates expected product distributions. We validate this algorithm by three sets of experiments whose analysis would probably prove challenging even to highly trained chemists: (1) predicting the outcomes of tail-to-head terpene (THT) cyclizations in which substantially different outcomes are encoded in modular precursors differing in minute structural details; (2) comparing the outcome of THT cyclizations in solution or in a supramolecular capsule; and (3) analysing complex reaction mixtures. Our results support a vision in which computers no longer just manipulate known reaction types but will help rationalize and discover new, mechanistically complex transformations.
地球科學Earth Science
Ubiquitous acceleration in Greenland Ice Sheet calving from 1985 to 2022
從1985年到2022年格陵蘭冰蓋崩解普遍加速
▲ 作者：Chad A. Greene, Alex S. Gardner, Michael Wood & Joshua K. Cuzzone
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06863-2
▲ 摘要：
在過去的幾十年里，格陵蘭島幾乎所有的冰川都變薄或退縮，導致冰川融化加速，海平面上升速度加快，并對全球氣候產生影響。
為了了解冰裂前沿退縮如何影響格陵蘭島的冰質量平衡，研究組結合了1985年至2022年收集的236328次人工推導和人工智能推導的冰川終點位置觀測數據，并在近40年里每月生成一個確定冰蓋范圍的120米分辨率的地圖。
結果表明，自1985年以來，格陵蘭冰蓋（GrIS）已損失了5091±72 km2的面積，對應于1034±120 Gt的冰損失。由于忽略了冰裂前緣退縮，目前對冰蓋質量平衡的共識估計低估了格陵蘭島最近的質量損失高達20%。此次報告的冰蓋質量損失對全球海平面的直接影響很小，但足以影響全球海洋環流和熱能的分布。
在季節性時間尺度上，格陵蘭島每年損失193±25 km2（63±6 Gt）的冰，5月冰損失最大，而9月至10月冰損失最小。研究結果發現，多年代際冰蓋退縮與每個冰川的季節性進退幅度高度相關，這意味著季節性時間尺度上的冰蓋終點位置變化可作為冰川對長期氣候變化敏感性的指標。
▲ Abstract：
Nearly every glacier in Greenland has thinned or retreated over the past few decades, leading to glacier acceleration, increased rates of sea-level rise and climate impacts around the globe. To understand how calving-front retreat has affected the ice-mass balance of Greenland, we combine 236,328 manually derived and AI-derived observations of glacier terminus positions collected from 1985 to 2022 and generate a 120-m-resolution mask defining the ice-sheet extent every month for nearly four decades. Here we show that, since 1985, the Greenland Ice Sheet (GrIS) has lost 5,091 ± 72 km2 of area, corresponding to 1,034 ± 120 Gt of ice lost to retreat. Our results indicate that, by neglecting calving-front retreat, current consensus estimates of ice-sheet mass balance have underestimated recent mass loss from Greenland by as much as 20%. The mass loss we report has had minimal direct impact on global sea level but is sufficient to affect ocean circulation and the distribution of heat energy around the globe. On seasonal timescales, Greenland loses 193 ± 25 km2 (63 ± 6 Gt) of ice to retreat each year from a maximum extent in May to a minimum between September and October. We find that multidecadal retreat is highly correlated with the magnitude of seasonal advance and retreat of each glacier, meaning that terminus-position variability on seasonal timescales can serve as an indicator of glacier sensitivity to longer-term climate change.
社會學Sociology
Online searches to evaluate misinformation can increase its perceived veracity
在線搜索以評估錯誤信息可提高其感知準確性
▲ 作者：Kevin Aslett, Zeve Sanderson, William Godel, Nathaniel Persily, Jonathan Nagler & Joshua A. Tucker
▲ 鏈接：
https://www.nature.com/articles/s41586-023-06883-y
▲ 摘要：
學術界對理解網上錯誤信息的信任度給予了相當大的關注，尤其關注社交網絡。然而，盡管使用在線搜索來評估信息真實性是媒介素養干預的核心組成部分，但搜索引擎在信息環境中的主導作用仍未得到充分探索。盡管傳統觀點認為，在評估錯誤信息時上網搜索會降低人們對它的信任度，但幾乎沒有實驗證據來評估這一說法。
通過五個實驗，研究組提出了一致的證據，證明在線搜索評估虛假新聞文章的真實性實際上增加了人們相信這些新聞的概率。為了闡明這種關系，他們將調查數據與使用自定義瀏覽器擴展收集的數字跟蹤數據結合起來。結果發現，搜索效果集中在搜索引擎返回低質量信息的個人身上。
該研究結果表明，那些在網上搜索以評估錯誤信息的人有陷入數據空白或低質量來源確鑿證據的信息空間的風險。研究組還發現一致的證據表明，在線搜索以評估新聞會增加人們對低質量來源真實新聞的信任度，但不一致的證據表明，其會增加人們對主流來源真實新聞的信任度。
該研究結果強調，媒體素養計劃需要將其建議建立在經過實證檢驗的策略基礎上，搜索引擎需要投資于該文所述挑戰的解決方案。
▲ Abstract：
Considerable scholarly attention has been paid to understanding belief in online misinformation, with a particular focus on social networks. However, the dominant role of search engines in the information environment remains underexplored, even though the use of online search to evaluate the veracity of information is a central component of media literacy interventions. Although conventional wisdom suggests that searching online when evaluating misinformation would reduce belief in it, there is little empirical evidence to evaluate this claim. Here, across five experiments, we present consistent evidence that online search to evaluate the truthfulness of false news articles actually increases the probability of believing them. To shed light on this relationship, we combine survey data with digital trace data collected using a custom browser extension. We find that the search effect is concentrated among individuals for whom search engines return lower-quality information. Our results indicate that those who search online to evaluate misinformation risk falling into data voids, or informational spaces in which there is corroborating evidence from low-quality sources. We also find consistent evidence that searching online to evaluate news increases belief in true news from low-quality sources, but inconsistent evidence that it increases belief in true news from mainstream sources. Our findings highlight the need for media literacy programmes to ground their recommendations in empirically tested strategies and for search engines to invest in solutions to the challenges identified here.
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