Nature, 14 July 2022, VOL 607, ISSUE 7918
《自然》2022年7月14日，第607卷，7918期
古生物学Paleontology
Grey wolf genomic history reveals a dual ancestry of dogs
灰狼基因组历史揭示狗的双重祖先
▲ 作者：Anders Bergstrm, David W. G. Stanton, Pontus Skoglund Show authors
▲ 链接：
https://www.nature.com/articles/s41586-022-04873-0
▲ 摘要：
灰狼是第一个在国内繁殖的物种，在许多其他大型哺乳动物灭绝的最后一个冰河时代，它们仍然广泛分布。然而，关于过去狼种群的历史和可能的灭绝，以及今天的犬系的狼祖先生活在何时何地，人们知之甚少。
作者分析了过去10万年间来自欧洲、西伯利亚和北美的72只远古狼的基因组。结果发现，在晚更新世时期，狼的种群之间有着高度的联系，它们的分化程度比现在低了一个数量级。这种群体连接使他们能够在时间序列中检测自然选择，包括4万至3万年前IFT88基因突变的快速固定。
该研究表明，总体而言，狗与来自欧亚大陆东部的古狼的关系比与来自欧亚大陆西部的狼的关系更密切，这表明狗在东方有一个驯化过程。
作者还发现，近东和非洲的狗有一半的祖先来自一个与现代西南欧亚狼相关的独特种群，这反映了要么是独立驯化的过程，要么是与当地狼的混合。分析的远古狼的基因组中没有一个与这些狗的祖先直接匹配，这意味着确切的祖先种群仍有待确定。
▲ Abstract：
The grey wolf (Canis lupus) was the first species to give rise to a domestic population, and they remained widespread throughout the last Ice Age when many other large mammal species went extinct. Little is known, however, about the history and possible extinction of past wolf populations or when and where the wolf progenitors of the present-day dog lineage (Canis familiaris) lived. Here we analysed 72 ancient wolf genomes spanning the last 100,000 years from Europe, Siberia and North America. We found that wolf populations were highly connected throughout the Late Pleistocene, with levels of differentiation an order of magnitude lower than they are today. This population connectivity allowed us to detect natural selection across the time series, including rapid fixation of mutations in the gene IFT88 40,000–30,000 years ago. We show that dogs are overall more closely related to ancient wolves from eastern Eurasia than to those from western Eurasia, suggesting a domestication process in the east. However, we also found that dogs in the Near East and Africa derive up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, reflecting either an independent domestication process or admixture from local wolves. None of the analysed ancient wolf genomes is a direct match for either of these dog ancestries, meaning that the exact progenitor populations remain to be located.
物理学Physics
Sub-second periodicity in a fast radio burst
快速射电暴中的亚秒周期
▲ 作者：The CHIME/FRB Collaboration, Bridget C. Andersen, Andrew Zwaniga Show authors
▲ 链接：
https://www.nature.com/articles/s41586-022-04841-8
▲ 摘要：
快速射电暴（FRB）是在数十亿光年以外可见的毫秒级无线电波闪光。其祖先的性质及其发射机制仍然是悬而未决的天体物理学问题。
作者报告了多组分FRB 20191221A的检测结果，其各组分之间的周期分离为216.8(1)ms，显著性为6.5σ。长时间（约3秒）的持续和9个或更多组成脉冲剖面的分量使该源成为FRB总体中的异常值。如此短的周期为事件的中子星起源提供了强有力的证据。
此外，作者表示该探测更倾向于从中子星磁层发出的辐射，而非像某些模型预测的那样，位于离恒星较远的区域。
▲ Abstract：
Fast radio bursts (FRBs) are millisecond-duration flashes of radio waves that are visible at distances of billions of light years. The nature of their progenitors and their emission mechanism remain open astrophysical questions. Here we report the detection of the multicomponent FRB 20191221A and the identification of a periodic separation of 216.8(1) ms between its components, with a significance of 6.5σ. The long (roughly 3s) duration and nine or more components forming the pulse profile make this source an outlier in the FRB population. Such short periodicity provides strong evidence for a neutron-star origin of the event. Moreover, our detection favours emission arising from the neutron-star magnetosphere, as opposed to emission regions located further away from the star, as predicted by some models5.
Optical observation of single spins in silicon
硅中单自旋的光学观察
▲ 作者：Daniel B. Higginbottom, Alexander T. K. Kurkjian, Camille Chartrand, Moein Kazemi, Nicholas A. Brunelle, Evan R. MacQuarrie, James R. Klein, Nicholas R. Lee-Hone, Jakub Stacho, Myles Ruether, Camille Bowness, Laurent Bergeron, Adam DeAbreu, Stephen R. Harrigan, Joshua Kanaganayagam, Danica W. Marsden, Timothy S. Richards, Leea A. Stott, Sjoerd Roorda, Kevin J. Morse, Michael L. W. Thewalt & Stephanie Simmons
▲ 链接：
https://www.nature.com/articles/s41586-022-04821-y
▲ 摘要：
全球量子互联网将需要大规模生产的长期、电信波段的光子与物质接口。基于光子-物质界面的初步量子网络满足了这些需求的一部分，这鼓励了寻找新的高性能替代品。
硅是商业规模固态量子技术的理想宿主。它已经是全球集成光子学和微电子工业的先进平台，同时也拥有创纪录的长寿命自旋量子比特。尽管硅量子平台具有压倒性的潜力，但硅中可单独寻址的光子自旋界面的光学检测仍然是难以捉摸的。
作者在硅光子结构中集成了单独可寻址的“T中心”光子-自旋量子比特，并描述了它们的自旋相关的电讯带光学跃迁。这些结果为构建硅集成的电信波段量子信息网络提供了直接的机会。
▲ Abstract：
The global quantum internet will require long-lived, telecommunications-band photon–matter interfaces manufactured at scale. Preliminary quantum networks based on photon–matter interfaces that meet a subset of these demands are encouraging efforts to identify new high-performance alternatives. Silicon is an ideal host for commercial-scale solid-state quantum technologies. It is already an advanced platform within the global integrated photonics and microelectronics industries, as well as host to record-setting long-lived spin qubits3. Despite the overwhelming potential of the silicon quantum platform, the optical detection of individually addressable photon–spin interfaces in silicon has remained elusive. In this work, we integrate individually addressable ‘T centre’ photon–spin qubits in silicon photonic structures and characterize their spin-dependent telecommunications-band optical transitions. These results unlock immediate opportunities to construct silicon-integrated, telecommunications-band quantum information networks.
化学Chemistry
Elastocaloric determination of the phase diagram of Sr2RuO4
Sr2RuO4相图的弹性热法测定
▲ 作者：You-Sheng Li, Markus Garst, Jörg Schmalian, Sayak Ghosh, Naoki Kikugawa, Dmitry A. Sokolov, Clifford W. Hicks, Fabian Jerzembeck, Matthias S. Ikeda, Zhenhai Hu, B. J. Ramshaw, Andreas W. Rost, Michael Nicklas & Andrew P. Mackenzie
▲ 链接：
https://www.nature.com/articles/s41586-022-04820-z
▲ 摘要：
过去二十年，非常规超导的主要发展之一是发现大多数非常规超导体形成的相图也包含其他强相关态。因此，许多感兴趣的系统都接近不止一种不稳定状态，而由此产生的有序相位之间的调谐是研究的重点。
近年来，使用压电器件施加的单轴压力已被证明是一种特别通用的新调谐方法，导致实验提高了非常规超导体Sr2RuO4的理解。作者使用高精度的弹性热效应测量绘制了其相图，他们表示这是第一个包括正常和超导态的相关研究。
在进入超导态时，他们观察到一个强烈的熵猝灭，这与范霍夫点配对的模型计算非常一致，并获得了在接近超导态时观察到的与进入磁态相关的熵变化的定量估计。相图之所以引人入胜，不仅是因为它与其他非常规超导体家族的相图相似，还因为Sr2RuO4迄今为止所特有的额外特征。
▲ Abstract：
One of the main developments in unconventional superconductivity in the past two decades has been the discovery that most unconventional superconductors form phase diagrams that also contain other strongly correlated states. Many systems of interest are therefore close to more than one instability, and tuning between the resultant ordered phases is the subject of intense research. In recent years, uniaxial pressure applied using piezoelectric-based devices has been shown to be a particularly versatile new method of tuning, leading to experiments that have advanced our understanding of the fascinating unconventional superconductor Sr2RuO4. Here we map out its phase diagram using high-precision measurements of the elastocaloric effect in what we believe to be the first such study including both the normal and the superconducting states. We observe a strong entropy quench on entering the superconducting state, in excellent agreement with a model calculation for pairing at the Van Hove point, and obtain a quantitative estimate of the entropy change associated with entry to a magnetic state that is observed in proximity to the superconductivity. The phase diagram is intriguing both for its similarity to those seen in other families of unconventional superconductors and for extra features unique, so far, to Sr2RuO4.
Odd dynamics of living chiral crystals
活性手性晶体的奇异动力学
▲ 作者：Tzer Han Tan, Alexander Mietke, Junang Li, Yuchao Chen, Hugh Higinbotham, Peter J. Foster, Shreyas Gokhale, Jrn Dunkel & Nikta Fakhri
▲ 链接：
https://www.nature.com/articles/s41586-022-04889-6
▲ 摘要：
活性晶体是由运动物体的自组织而产生的高度有序结构，在合成活性物质和细菌活性物质中得到了广泛的研究。在自主发展的多细胞生物群中，是否会出现持续的晶体秩序，目前尚不清楚。
作者展示了游动的海星胚胎自发地组装成手性晶体，跨越数千个旋转的生物体，并持续数十小时。结合实验、理论和模拟，他们证明了这些活晶体的形成、动力学和溶解受水动力学特性和胚胎自然发育的控制。
值得注意的是，活的手性晶体表现出自我持续的手性振荡，以及各种非常规的形变响应行为，最近预测奇数弹性材料的形变响应行为。该结果为自主多细胞组分之间的非互反作用如何促进手性活性物质的非平衡相提供了直接的实验证据。
▲ Abstract：
Active crystals are highly ordered structures that emerge from the self-organization of motile objects, and have been widely studied in synthetic and bacterial active matter. Whether persistent crystalline order can emerge in groups of autonomously developing multicellular organisms is currently unknown. Here we show that swimming starfish embryos spontaneously assemble into chiral crystals that span thousands of spinning organisms and persist for tens of hours. Combining experiments, theory and simulations, we demonstrate that the formation, dynamics and dissolution of these living crystals are controlled by the hydrodynamic properties and the natural development of embryos. Remarkably, living chiral crystals exhibit self-sustained chiral oscillations as well as various unconventional deformation response behaviours recently predicted for odd elastic materials. Our results provide direct experimental evidence for how non-reciprocal interactions between autonomous multicellular components may facilitate non-equilibrium phases of chiral active matter.
Local nanoscale phase impurities are degradation sites in halide perovskites
局部纳米级相杂质是卤化物钙钛矿中的降解位点
▲ 作者：Stuart Macpherson, Tiarnan A. S. Doherty, Andrew J. Winchester, Sofiia Kosar, Duncan N. Johnstone, Yu-Hsien Chiang, Krzysztof Galkowski, Miguel Anaya, Kyle Frohna, Affan N. Iqbal, Satyawan Nagane, Bart Roose, Zahra Andaji-Garmaroudi, Kieran W. P. Orr, Julia E. Parker, Paul A. Midgley, Keshav M. Dani & Samuel D. Stranks
▲ 链接：
https://www.nature.com/articles/s41586-022-04872-1
▲ 摘要：
了解纳米级的化学和结构变化驱动新兴能源材料的不稳定性，对缓解设备退化至关重要。卤化物钙钛矿光伏器件的功率转换效率在单结中达到了25.7%，在钙钛矿/硅电池的串联中达到了29.8%，然而在连续操作中保持这样的性能仍然难以实现。
作者开发了一个多模态显微镜工具包，以揭示在主要的富甲脒钙钛矿吸收剂中，纳米级相杂质，包括六边形多型和碘化铅夹杂物，不仅是光激发载流子的陷阱，这本身降低了性能，而且，通过相同的陷阱过程，是吸收层光化学降解的位点。
他们可视化了照明引起的与陷阱簇相关的相杂质的结构变化，揭示了即使是微量的这些相，否则批量测量无法检测到，也会损害器件寿命。这些不需要的相夹杂物的类型和分布取决于薄膜的组成和处理，而多型的存在对薄膜的光稳定性最不利。
重要的是，他们揭示了通过调制这些缺陷相杂质可以缓解性能损失和内在降解过程，并表明这需要仔细调整局部结构和化学性质。这种多模态的工作流程将光束敏感的能量材料的纳米形态联系起来，将适用于广泛的半导体，这些半导体的性能和操作稳定性的局部图景尚未建立。
▲ Abstract：
Understanding the nanoscopic chemical and structural changes that drive instabilities in emerging energy materials is essential for mitigating device degradation. The power conversion efficiency of halide perovskite photovoltaic devices has reached 25.7 per cent in single-junction and 29.8 per cent in tandem perovskite/silicon cells, yet retaining such performance under continuous operation has remained elusive. Here we develop a multimodal microscopy toolkit to reveal that in leading formamidinium-rich perovskite absorbers, nanoscale phase impurities, including hexagonal polytype and lead iodide inclusions, are not only traps for photoexcited carriers, which themselves reduce performance, but also, through the same trapping process, are sites at which photochemical degradation of the absorber layer is seeded. We visualize illumination-induced structural changes at phase impurities associated with trap clusters, revealing that even trace amounts of these phases, otherwise undetected with bulk measurements, compromise device longevity. The type and distribution of these unwanted phase inclusions depends on the film composition and processing, with the presence of polytypes being most detrimental for film photo-stability. Importantly, we reveal that both performance losses and intrinsic degradation processes can be mitigated by modulating these defective phase impurities, and demonstrate that this requires careful tuning of local structural and chemical properties. This multimodal workflow to correlate the nanoscopic landscape of beam-sensitive energy materials will be applicable to a wide range of semiconductors for which a local picture of performance and operational stability has yet to be established.
转自：科学网
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