編譯 | 李言
Science, 07 MAY 2021, VOL 372, ISSUE 6542
《科學》2021年5月7日，第372卷，6542期
古人類學Paleoanthropology
Unearthing Neanderthal population history using nuclear and mitochondrial DNA from cave sediments
利用洞穴沉積物中的核和線粒體DNA挖掘尼安德特人的種群歷史
▲ 作者：Benjamin Vernot, Elena I. Zavala, Asier Gómez-Olivencia, Zenobia Jacobs, et al.
▲ 鏈接：
https://science.sciencemag.org/content/372/6542/eabf1667
▲ 摘要
骨頭和牙齒是更新世人類DNA的重要來源，但很少在考古遺址中發現。從洞穴沉積物中可以提取到線粒體DNA（mtDNA），但它們對種群關係的研究價值有限。
因此，我們開發了收集和分析沉積物中核DNA的方法，並將其應用於20萬至5萬年前的西歐和西伯利亞南部的洞穴沉積物中。
我們在大約10萬年前的西班牙北部發現了一個伴隨着mtDNA更替的種群更替。我們還確定了尼安德特人在晚更新世早期的兩次輻射進化事件。我們的工作為從沉積物中微量的核DNA研究古人類的種群歷史奠定了基礎。
▲ Abstract
Bones and teeth are important sources of Pleistocene hominin DNA, but are rarely recovered at archaeological sites. Mitochondrial DNA (mtDNA) has been retrieved from cave sediments but provides limited value for studying population relationships. We therefore developed methods for the enrichment and analysis of nuclear DNA from sediments and applied them to cave deposits in western Europe and southern Siberia dated to between 200,000 and 50,000 years aGO. We detected a population replacement in northern Spain about 100,000 years ago, which was accompanied by a turnover of mtDNA. We also identified two radiation events in Neanderthal history during the early part of the Late Pleistocene. Our work lays the ground for studying the population history of ancient hominins from trace amounts of nuclear DNA in sediments.
古生物學Paleobiology
Evolution of vision and hearing modalities in theropod dinosaurs
獸腳類恐龍視覺和聽覺模式的進化
▲ 作者：Jonah N. Choiniere, James M. Neenan, Lars Schmitz, David P. Ford, et al.
▲ 鏈接：
https://science.sciencemag.org/content/372/6542/610
▲ 摘要
貓頭鷹和夜鶯是在夜間活動的獵食者，它們結合了視覺和聽覺的改變，以克服在弱光下感官表現的限制。這種感官改變在非鳥類的獸腳類恐龍中未被發現，並且在向鳥類進化的譜系中極少被確認。
我們研究了現存和滅絕的獸腳亞目動物的視覺和聽覺的形態功能代理，並證明了感官模式的深度進化分歧。夜行性捕食在非鳥類的阿瓦拉慈龍類早期就進化出來了，表現為極弱的視力和聽覺敏感度的增加。
晚白堊紀的沙漠鳥面龍擁有更特殊的聽力，可以與今天的倉鴞媲美。早在現代鳥類輻射進化出現之前，這種感覺適應能力的結合就在恐龍身上獨立進化，並為恐龍和哺乳動物的融合提供了一個顯著的例子。
▲ Abstract
Owls and nightbirds are nocturnal hunters of active prey that combine visual and hearing adaptations to overcome limits on sensory performance in low light. Such sensory innovations are unknown in nonavialan theropod dinosaurs and are poorly characterized on the line that leads to birds. We investigate morphofunctional proxies of vision and hearing in living and extinct theropods and demonstrate deep evolutionary divergences of sensory modalities. Nocturnal predation evolved early in the nonavialan lineage Alvarezsauroidea, signaled by extreme low-light vision and increases in hearing sensitivity. The Late Cretaceous alvarezsauroid Shuvuuia deserti had even further specialized hearing acuity, rivaling that of today』s barn owl. This combination of sensory adaptations evolved independently in dinosaurs long before the modern bird radiation and provides a notable example of convergence between dinosaurs and mammals.
材料科學Materials Science
Reversible fusion and fission of graphene oxide–based fibers
氧化石墨烯纖維的可逆融合和分裂
▲ 作者：Dan Chang, Jingran Liu, Bo Fang, Zhen Xu, et al.
▲ 鏈接：
https://science.sciencemag.org/content/372/6542/614
▲ 摘要
刺激反應融合和分裂在生物組織和人工分子組裝中被廣泛觀察到。然而，在重複聚變和分裂的過程中，設計一個結構和性能持久的系統仍然具有挑戰性。
我們研究了氧化石墨烯（GO）纖維的可逆融合和分裂，在溶劑的刺激下，許多宏觀纖維可以融合成較厚的纖維，也可以分離成原始的單個纖維。
氧化石墨烯纖維殼層由溶劑蒸發和滲透引起的動態幾何變形是實現可逆聚變-裂變循環的關鍵。這一原理被擴展到實現複雜纖維組件和客體化合物的包含或排出之間的靈活轉化。
▲ Abstract
Stimuli-responsive fusion and fission are widely observed in both bio-organizations and artificial molecular assemblies. However, the design of a system with structure and property persistence during repeated fusion and fission remains challenging. We show reversible fusion and fission of wet-spun graphene oxide (GO) fibers, in which a number of macroscopic fibers can fuse into a thicker one and can also separate into original individual fibers under stimulation of solvents. The dynamic geometrical deformation of GO fiber shells, caused by solvent evaporation and infiltration, is the key to the reversible fusion-fission cycles. This principle is extended to implement flexible transitions between complex fiber assemblies and the inclusion or expulsion of guest compounds.
量子物理Quantum Physics
Direct observation of deterministic macroscopic entanglement
宏觀物體量子糾纏的直接證據
▲ 作者：Shlomi Kotler, Gabriel A. Peterson, Ezad Shojaee, Florent Lecocq, et al.
▲ 鏈接：
https://science.sciencemag.org/content/372/6542/622
▲ 摘要
機械系統的量子糾纏是在不同的物體運動時產生的，它們之間的關聯程度如此之高，以至於不能夠被單獨描述。
雖然量子力學可能適用於各種大小的物體，但隨着質量的增加，直接觀測糾纏變得具有挑戰性，需要以極小的誤差進行測量和控制。
在這裡，使用脈衝電學，我們確定地使質量為70微克的兩個機械鼓面糾纏在一起。通過近量子極限測量兩個鼓的位置和動量積分，我們進行了量子態斷層掃描，從而直接觀察糾纏。
這種糾纏的宏觀系統將在量子力學的基礎測試中發揮作用，使感知超越標準量子極限成為可能，並作為未來量子網絡的長期網絡節點發揮作用。
▲ Abstract
Quantum entanglement of mechanical systems emerges when distinct objects move with such a high degree of correlation that they can no longer be described separately. Although quantum mechanics presumably applies to objects of all sizes, directly observing entanglement becomes challenging as masses increase, requiring measurement and control with a vanishingly small error. Here, using pulsed electromechanics, we deterministically entangle two mechanical drumheads with masses of 70 picograms. Through nearly quantum-limited measurements of the position and momentum quadratures of both drums, we perform quantum state tomography and thereby directly observe entanglement. Such entangled macroscopic systems are poised to serve in fundamental tests of quantum mechanics, enable sensing beyond the standard quantum limit, and function as long-lived nodes of future quantum networks.
Quantum mechanics–free subsystem with mechanical oscillators
帶有機械振蕩器的無量子力學子系統
▲ 作者：Laure Mercier de Lépinay, Caspar F. Ockeloen-Korppi, Matthew J. Woolley, Mika A. Sillanpää
▲ 鏈接：
https://science.sciencemag.org/content/372/6542/625
▲ 摘要
量子力學為連續測量振蕩器位置的精度設定了一個極限。我們通過構造一個有效的振蕩器，展示了如何測量一個沒有測量量子反作用的振蕩器。
我們利用兩個微機械振蕩器實現了這樣一個不涉及量子力學的子系統，並顯示了兩個集體求積的測量結果，同時對它們都避開了8分貝的量子反作用，獲得了一個在完全量子極限的2倍以內的總噪聲。
這有助於弱力的檢測和振蕩器非經典運動狀態的產生和測量。此外，我們通過測量在可分性界下1.4分貝的段量，直接驗證了兩個振蕩器的量子糾纏。
▲ Abstract
Quantum mechanics sets a limit for the precision of continuous measurement of the position of an oscillator. We show how it is possible to measure an oscillator without quantum back-action of the measurement by constructing one effective oscillator from two physical oscillators. We realize such a quantum mechanics–free subsystem using two micromechanical oscillators, and show the measurements of two collective quadratures while evading the quantum back-action by 8 decibels on both of them, obtaining a total noise within a factor of 2 of the full quantum limit. This facilitates the detection of weak forces and the generation and measurement of nonclassical motional states of the oscillators. Moreover, we directly verify the quantum entanglement of the two oscillators by measuring the Duan quantity 1.4 decibels below the separability bound.
動物學Zoology
Extreme altitudes during diurnal flights in a nocturnal songbird migrant
夜間鳴禽候鳥在日間飛行時的極端高度
▲ 作者：Sissel Sjöberg, Gintaras Malmiga, Andreas Nord, Arne Andersson, et al.
▲ 鏈接：
https://science.sciencemag.org/content/372/6542/646
▲ 摘要
數十億隻夜間遷徙的鳴禽每年都會飛越海洋和沙漠。通過使用多傳感器數據記錄器，我們發現，大葦鶯（Acrocephalus arundinaceus）在穿越地中海和撒哈拉沙漠時，會定期將它們本來只能在夜間飛行的飛行時間延長至白天。
出乎意料的是，當延長飛行時間時，他們在黎明時陡然攀升，從平均海拔2394米上升到日間飛行的極端高度（平均海拔5367米，最高海拔6267米）。
這種以前不為人知的在白天遷徙時使用非常高的飛行高度的行為可能是由環境溫度、風、捕食、視野範圍和太陽輻射的日變化引起的。我們對這一行為的發現為鳥類飛行限制提供了新的視角，並可能有助於解釋夜間遷徙的進化。
▲ Abstract
Billions of nocturnally migrating songbirds fly across oceans and deserts on their annual journeys. Using multisensor data loggers, we show that great reed warblers (Acrocephalus arundinaceus) regularly prolong their otherwise strictly nocturnal flights into daytime when crossing the Mediterranean Sea and the Sahara Desert. Unexpectedly, when prolonging their flights, they climbed steeply at dawn, from a mean of 2394 meters above sea level to reach extreme cruising altitudes (mean 5367 and maximum 6267 meters above sea level) during daytime flights. This previously unknown behavior of using exceedingly high flight altitudes when migrating during daytime could be caused by diel variation in ambient temperature, winds, predation, vision range, and solar radiation. Our finding of this notable behavior provides new perspectives on constraints in bird flight and might help to explain the evolution of nocturnal migration.
