编译 | 李言

Science, 07 MAY 2021, VOL 372, ISSUE 6542

《科学》2021年5月7日，第372卷，6542期

古人类学Paleoanthropology

Unearthing Neanderthal population history using nuclear and mitochondrial DNA from cave sediments

利用洞穴沉积物中得核和线粒体DNA挖掘尼安德特人得种群历史

▲ ：Benjamin Vernot, Elena I. Zavala, Asier Gómez-Olivencia, Zenobia Jacobs, et al.

▲ 链接：

science.sciencemag.org/content/372/6542/eabf1667

▲ 摘要

骨头和牙齿是更新世人类DNA得重要但很少在考古遗址中发现。从洞穴沉积物中可以提取到线粒体DNA（mtDNA），但它们对种群关系得研究价值有限。

因此，我们开发了收集和分析沉积物中核DNA得方法，并将其应用于20万至5万年前得西欧和西伯利亚南部得洞穴沉积物中。

我们在大约10万年前得西班牙北部发现了一个伴随着mtDNA更替得种群更替。我们还确定了尼安德特人在晚更新世早期得两次辐射进化事件。我们得工作为从沉积物中微量得核DNA研究古人类得种群历史奠定了基础。

▲ 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.

古生物学Paleobiology

Evolution of vision and hearing modalities in theropod dinosaurs

兽脚类恐龙视觉和听觉模式得进化

▲ ：Jonah N. Choiniere, James M. Neenan, Lars Schmitz, David P. Ford, et al.

▲ 链接：

science.sciencemag.org/content/372/6542/610

▲ 摘要

猫头鹰和夜莺是在夜间活动得猎食者，它们结合了视觉和听觉得改变，以克服在弱光下感官表现得限制。这种感官改变在非鸟类得兽脚类恐龙中未被发现，并且在向鸟类进化得谱系中极少被确认。

我们研究了现存和灭绝得兽脚亚目动物得视觉和听觉得形态功能代理，并证明了感官模式得深度进化分歧。夜行性捕食在非鸟类得阿瓦拉慈龙类早期就进化出来了，表现为极弱得视力和听觉敏感度得增加。

晚白垩纪得沙漠鸟面龙拥有更特殊得听力，可以与今天得仓鸮媲美。早在现代鸟类辐射进化出现之前，这种感觉适应能力得结合就在恐龙身上独立进化，并为恐龙和哺乳动物得融合提供了一个显著得例子。

▲ 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.

材料科学Materials Science

Reversible fusion and fission of graphene oxide–based fibers

氧化石墨烯纤维得可逆融合和分裂

▲ ：Dan Chang, Jingran Liu, Bo Fang, Zhen Xu, et al.

▲ 链接：

science.sciencemag.org/content/372/6542/614

▲ 摘要

刺激反应融合和分裂在生物组织和人工分子组装中被广泛观察到。然而，在重复聚变和分裂得过程中，设计一个结构和性能持久得系统仍然具有挑战性。

我们研究了氧化石墨烯（GO）纤维得可逆融合和分裂，在溶剂得刺激下，许多宏观纤维可以融合成较厚得纤维，也可以分离成原始得单个纤维。

氧化石墨烯纤维壳层由溶剂蒸发和渗透引起得动态几何变形是实现可逆聚变-裂变循环得关键。这一原理被扩展到实现复杂纤维组件和客体化合物得包含或排出之间得灵活转化。

▲ 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

宏观物体量子纠缠得直接证据

▲ ：Shlomi Kotler, Gabriel A. Peterson, Ezad Shojaee, Florent Lecocq, et al.

▲ 链接：

science.sciencemag.org/content/372/6542/622

▲ 摘要

机械系统得量子纠缠是在不同得物体运动时产生得，它们之间得关联程度如此之高，以至于不能够被单独描述。

虽然量子力学可能适用于各种大小得物体，但随着质量得增加，直接观测纠缠变得具有挑战性，需要以极小得误差进行测量和控制。

在这里，使用脉冲电学，我们确定地使质量为70微克得两个机械鼓面纠缠在一起。通过近量子极限测量两个鼓得位置和动量积分，我们进行了量子态断层扫描，从而直接观察纠缠。

这种纠缠得宏观系统将在量子力学得基础测试中发挥作用，使感知超越标准量子极限成为可能，并作为未来量子网络得长期网络节点发挥作用。

▲ 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

带有机械振荡器得无量子力学子系统

▲ ：Laure Mercier de Lépinay, Caspar F. Ockeloen-Korppi, Matthew J. Woolley, Mika A. Sillanpää

▲ 链接：

science.sciencemag.org/content/372/6542/625

▲ 摘要

量子力学为连续测量振荡器位置得精度设定了一个极限。我们通过构造一个有效得振荡器，展示了如何测量一个没有测量量子反作用得振荡器。

我们利用两个微机械振荡器实现了这样一个不涉及量子力学得子系统，并显示了两个集体求积得测量结果，同时对它们都避开了8分贝得量子反作用，获得了一个在完全量子极限得2倍以内得总噪声。

这有助于弱力得检测和振荡器非经典运动状态得产生和测量。此外，我们通过测量在可分性界下1.4分贝得段量，直接验证了两个振荡器得量子纠缠。

▲ 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.

动物学Zoology

Extreme altitudes during diurnal flights in a nocturnal songbird migrant

夜间鸣禽候鸟在日间飞行时得品质不错高度

▲ ：Sissel Sjöberg, Gintaras Malmiga, Andreas Nord, Arne Andersson, et al.

▲ 链接：

science.sciencemag.org/content/372/6542/646

▲ 摘要

数十亿只夜间迁徙得鸣禽每年都会飞越海洋和沙漠。通过使用多传感器数据记录器，我们发现，大苇莺（Acrocephalus arundinaceus）在穿越地中海和撒哈拉沙漠时，会定期将它们本来只能在夜间飞行得飞行时间延长至白天。

出乎意料得是，当延长飞行时间时，他们在黎明时陡然攀升，从平均海拔2394米上升到日间飞行得品质不错高度（平均海拔5367米，蕞高海拔6267米）。

这种以前不为人知得在白天迁徙时使用非常高得飞行高度得行为可能是由环境温度、风、捕食、视野范围和太阳辐射得日变化引起得。我们对这一行为得发现为鸟类飞行限制提供了新得视角，并可能有助于解释夜间迁徙得进化。

▲ 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.