編譯 | 李言
Nature, 11 August 2022, Volume 608 Issue 7922
《自然》 2022年8月11日，第608卷，7922期
材料科學Material Science
Quantum cascade of correlated phases in trigonally warped bilayer graphene
三角彎曲雙層石墨烯中相關相的量子級聯(lián)
作者：Anna M. Seiler, Fabian R. Geisenhof, Felix Winterer et al.
鏈接：
https://www.nature.com/articles/s41586-022-04937-1
摘要：
在此，我們報告在伯納爾雙層石墨烯中電場控制的Lifshitz轉(zhuǎn)變和范霍夫奇點附近觀察到的一系列相關相。我們?yōu)橛^察到以半金屬和四分之一金屬形式的斯通納鐵磁體提供了證據(jù)。
此外，我們確定了在零磁場下拓撲非平凡維格納-霍爾晶體及其向平凡維格納晶體轉(zhuǎn)變的特征，以及兩種行為與標準費米液體的行為相偏離的相關金屬。我們在這個可重復的、可調(diào)的、簡單的系統(tǒng)中的結(jié)果為研究強相關電子研究打開了新的視野。
Abstract：
Here we report the observation of a cascade of correlated phases in the vicinity of electric-field-controlled Lifshitz transitions and van Hove singularities in Bernal bilayer graphene. We provide evidence for the observation of Stoner ferromagnets in the form of half and quarter metals. Furthermore, we identify signatures consistent with a topologically non-trivial Wigner–Hall crystal at zero magnetic field and its transition to a trivial Wigner crystal, as well as two correlated metals whose behaviour deviates from that of standard Fermi liquids. Our results in this reproducible, tunable, simple system open up new horizons for studying strongly correlated electrons.
A mechanically strong and ductile soft magnet with extremely low coercivity
一種高強高塑、極低矯頑力的軟磁體
作者：Liuliu Han, Fernando Maccari, Isnaldi R. Souza Filho et al.
鏈接：
https://www.nature.com/articles/s41586-022-04935-3
摘要：
交通、家庭和制造業(yè)的電氣化，由于滯后損失，導致能源消耗增加。因此，降低矯頑力是至關重要的，它可以衡量這些損失。然而，僅僅實現(xiàn)這一目標是不夠的：電機中的微型微結(jié)構(gòu)元件必須承受嚴重的機械負載；也就是說，合金需要高強度和延展性。
在此，我們介紹一種克服此類困境的方法。我們設計了一種Fe-Co-Ni-Ta-Al多元合金（MCA），它具有鐵磁基體和順磁性相干納米顆粒（尺寸約為 91nm，體積分數(shù)約為 55%）。它們阻礙位錯運動，增加強度和延展性。它們的小尺寸、低相干應力和小靜磁能在磁疇壁寬度以下產(chǎn)生相互作用體積，導致疇壁釘扎最小化，從而保持軟磁性。
這種合金在54%的拉伸伸長率下抗拉強度為1336 MPa，矯頑力為78 Am 1（小于1 Oe），飽和磁化強度為100 A?m2?kg 1，電阻率為103 μΩ cm。
Abstract：
The electrification of transport, households and manufacturing leads to an increase in energy consumption owing to hysteresis losses. Therefore, minimizing coercivity, which scales these losses, is crucial. Yet meeting this target alone is not enough: SMMs in electrical engines must withstand severe mechanical loads; that is, the alloys need high strength and ductility. Here we introduce an approach to overcome this dilemma. We have designed a Fe–Co–Ni–Ta–Al multicomponent alloy (MCA) with ferromagnetic matrix and paramagnetic coherent nanoparticles (about 91?nm in size and around 55% volume fraction). They impede dislocation motion, enhancing strength and ductility. Their small size, low coherency stress and small magnetostatic energy create an interaction volume below the magnetic domain wall width, leading to minimal domain wall pinning, thus maintaining the soft magnetic properties. The alloy has a tensile strength of 1,336?MPa at 54% tensile elongation, extremely low coercivity of 78?Am 1 (less than 1?Oe), moderate saturation magnetization of 100?A?m2?kg 1 and high electrical resistivity of 103?μΩ?cm.
物理學Physics
Self-emergence of robust solitons in a microcavity
微腔中魯棒孤子的自出現(xiàn)
作者：Maxwell Rowley, Pierre-Henry Hanzard, Antonio Cutrona et al.
鏈接：
https://www.nature.com/articles/s41586-022-04957-x
摘要：
在此，我們展示了自由運行的微諧振濾波器光纖激光器的慢非線性可以將時間腔孤子轉(zhuǎn)化為系統(tǒng)的主要吸引子。這一現(xiàn)象導致了微腔孤子可靠的自啟動振蕩，對擾動具有天然的魯棒性，即使在完全中斷后也能自動恢復。
這些情況可在球形系統(tǒng)參數(shù)空間的的大區(qū)域中重復且可控地出現(xiàn)，在這個區(qū)域中，可以實現(xiàn)特定狀態(tài)的長期高度穩(wěn)定。
Abstract：
Here we show that the slow non-linearities of a free-running microresonator-filtered fibre laser can transform temporal cavity solitons into the system’s dominant attractor. This phenomenon leads to reliable self-starting oscillation of microcavity solitons that are naturally robust to perturbations, recovering spontaneously even after complete disruption. These emerge repeatably and controllably into a large region of the global system parameter space in which specific states, highly stable over long timeframes, can be achieved.
地球科學Earth science
Giant impacts and the origin and evolution of continents
大碰撞及大陸的起源和演化
作者：Tim E. Johnson, Christopher L. Kirkland, Yongjun Lu et al.
鏈接：
https://www.nature.com/articles/s41586-022-04956-y
摘要：
地球是已知的唯一有大陸的行星，盡管大陸形成和演化的方式尚不清楚。在此，通過對巖漿鋯石的氧同位素分析，我們發(fā)現(xiàn)西澳大利亞皮爾巴拉克拉頓是地球上保存最完好的太古宙（40 – 25億年前）大陸遺跡，它的形成經(jīng)歷了三個階段。第一階段鋯石（3.6 ~ 3.4 Ga）形成兩個團簇，其中1 / 3記錄為下地幔δ18O，表明巖漿來自于熱液蝕變的玄武巖地殼（如今天的冰島）。
淺層融化與代表地球最初10億年歷史的大碰撞是一致的。大碰撞為地殼破裂提供了動力，并通過與全球廣泛的海洋的相互作用建立了長期的熱液蝕變。大約發(fā)生在3.6 Ga的一次巨大撞擊，與最古老的低δ18O鋯石同時代，可能會觸發(fā)大規(guī)模的地幔融化，產(chǎn)生厚的鎂鐵質(zhì)-超鎂鐵質(zhì)核。
另一個低δ18O鋯石簇約為3.4 Ga，與球粒層同生，為地球上的巨大撞擊提供了最古老的物質(zhì)證據(jù)。第2階段（3.4 ~ 3.0 Ga）鋯石的δ18O多為類似地幔δ18O，主要來源于大陸核基底附近的母巖漿。第三階段（<3.0 Ga）鋯石δ18O具有上地幔特征，反映了表殼巖石的高效循環(huán)。最古老的長英質(zhì)巖石形成于3.9-3.5 Ga，接近所謂的晚期重轟擊末期，并非巧合。
Abstract：
Earth is the only planet known to have continents, although how they formed and evolved is unclear. Here using the oxygen isotope compositions of dated magmatic zircon, we show that the Pilbara Craton in Western Australia, Earth’s best-preserved Archaean (4.0–2.5 billion years ago (Ga)) continental remnant, was built in three stages. Stage 1 zircons (3.6–3.4?Ga) form two age clusters with one-third recording submantle δ18O, indicating crystallization from evolved magmas derived from hydrothermally altered basaltic crust like that in modern-day Iceland. Shallow melting is consistent with giant impacts that typified the first billion years of Earth history. Giant impacts provide a mechanism for fracturing the crust and establishing prolonged hydrothermal alteration by interaction with the globally extensive ocean. A giant impact at around 3.6?Ga, coeval with the oldest low-δ18O zircon, would have triggered massive mantle melting to produce a thick mafic–ultramafic nucleus. A second low-δ18O zircon cluster at around 3.4?Ga is contemporaneous with spherule beds that provide the oldest material evidence for giant impacts on Earth. Stage 2 (3.4–3.0?Ga) zircons mostly have mantle-like δ18O and crystallized from parental magmas formed near the base of the evolving continental nucleus. Stage 3 (<3.0?Ga) zircons have above-mantle δ18O, indicating efficient recycling of supracrustal rocks. That the oldest felsic rocks formed at 3.9–3.5?Ga, towards the end of the so-called late heavy bombardment, is not a coincidence.
生物學Biology
Dairying, diseases and the evolution of lactase persistence in Europe
歐洲的乳業(yè)、疾病和乳糖酶持久性的演變
作者：Richard P. Evershed, George Davey Smith, Mélanie Roffet-Salque et al.
鏈接：
https://www.nature.com/articles/s41586-022-05010-7
摘要：
在歐洲和許多非洲、中東和南亞人口中，乳糖耐受性（LP）是在過去1萬年中進化出來的最強烈的單基因性狀。在此，我們提供了歐洲在過去9000年里在550多個考古遺址的約7000個陶器脂肪殘留物中提取牛奶的詳細分布。從新石器時代，歐洲開始廣泛飲用牛奶，但在空間和時間上的強度不同。
值得注意的是，與新石器時代，隨著史前牛奶飲用水平的不同而變化的乳糖耐受性選擇并不更能解釋乳糖耐受性等位基因頻率軌跡。在英國生物庫50萬名當代歐洲人的隊列研究中，乳糖耐受性基因型與牛奶攝入量的相關性較弱，與改善體質(zhì)或健康指標的相關性不一致。這表明，乳糖耐受性的頻率快速增加應考慮其他原因，使其有益的影響。
我們認為，乳糖酶不持久的個體在牛奶有供應時飲用牛奶，但在饑荒和/或病原體暴露增加的條件下不飲用，推動了史前歐洲人的乳糖耐受性選擇。模型似然值的比較表明，種群波動、聚居密度和野生動物開發(fā)利用作為這些驅(qū)動因素的替代物，比牛奶飲用程度更能解釋乳糖耐受性的改變。這些發(fā)現(xiàn)為史前牛奶飲用和乳糖耐受性進化提供了新的視角。
Abstract：
In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000?years. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000?years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent inpiduals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation—proxies for these drivers—provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.
古生物學Paleontology
The developing bird pelvis passes through ancestral dinosaurian conditions
作者：Christopher T. Griffin, Jo?o F. Botelho, Michael Hanson et al.
鏈接：
https://www.nature.com/articles/s41586-022-04982-w
摘要：
我們使用胚胎學成像技術在三個維度上檢查鳥類盆腔組織的形態(tài)發(fā)生，與化石記錄進行直接比較。許多恐龍祖先的特征（例如，前向恥骨、短髂骨和恥骨）在鳥類的早期形態(tài)發(fā)生中短暫存在，并通過反映特征獲得的系統(tǒng)發(fā)育序列的產(chǎn)前發(fā)育序列過渡后達到典型的“活鳥”形態(tài)。
我們定量地證明了鳥類骨盆個體發(fā)生與非鳥類恐龍到鳥類的轉(zhuǎn)變相似，并為骨盆內(nèi)表型協(xié)方差提供了證據(jù)。鳥類胚胎中存在的祖先狀態(tài)可能源于這種保守的協(xié)變關系。
總之，我們的數(shù)據(jù)提供了證據(jù)，證明鳥類骨盆的早期發(fā)育是通過末端附加的機制進化的，即新的非形形狀態(tài)被添加到發(fā)育序列的末端，導致該序列中更早的祖先特征狀態(tài)的表達。
Abstract：
We used embryological imaging techniques to examine the morphogenesis of avian pelvic tissues in three dimensions, allowing direct comparison with the fossil record. Many ancestral dinosaurian features (for example, a forward-facing pubis, short ilium and pubic ‘boot’) are transiently present in the early morphogenesis of birds and arrive at their typical ‘a(chǎn)vian’ form after transitioning through a prenatal developmental sequence that mirrors the phylogenetic sequence of character acquisition. We demonstrate quantitatively that avian pelvic ontogeny parallels the non-avian dinosaur-to-bird transition and provide evidence for phenotypic covariance within the pelvis that is conserved across Archosauria. The presence of ancestral states in avian embryos may stem from this conserved covariant relationship. In sum, our data provide evidence that the avian pelvis, whose early development has been little studied, evolved through terminal addition—a mechanism whereby new apomorphic states are added to the end of a developmental sequence, resulting in expression8,11 of ancestral character states earlier in that sequence.
