编译 | 冯维维

Nature, 30 April 2020, Volume 580 Issue 7805

《自然》2020年4月30日，第580卷，7805期

物理学Physics

Nightside condensation of iron in an ultrahot giant exoplanet

铁元素在超热巨大系外行星夜间凝结

▲ 作者：David Ehrenreich, Christophe Lovis, Filippo Zerbi, etc.

▲ 链接：https://www.nature.com/articles/s41586-020-2107-1

▲ 摘要

超热的巨大系外行星接受的日照是地球的数千倍。它们的高温环境是研究极端行星气候和化学的理想实验室。

作者报告了在超热的外行星WASP-76b上探测到的非对称大气信号。他们使用高分散光谱学和一个大的光子收集区相结合的方法来解决这个信号。中性铁的吸收信号在尾缘以每秒- 11±0.7公里的速度发生蓝移，这可以用行星自转和白天吹来的热风的组合来解释。

相反，靠近晨光明暗界线的一侧没有信号，表明铁原子没有吸收那里的星光。作者由此得出结论，铁在穿越该行星背面的过程中必然会凝结。

▲ Abstract

Ultrahot giant exoplanets receive thousands of times Earth’s insolation. Their high-temperature atmospheres are ideal laboratories for studying extreme planetary climates and chemistry. Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by −11 ± 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside16. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.

Months-long thousand-kilometre-scale wobbling before great subduction earthquakes

大俯冲地震前长达数月的数千公里范围的抖动

▲ 作者：Jonathan R. Bedford, Marcos Moreno, Zhiguo Deng, Onno Oncken, Bernd Schurr, Timm John, Juan Carlos Báez, Michael Bevis

▲ 链接：https://www.nature.com/articles/s41586-020-2212-1

▲ 摘要

大推力地震是造成一些最具破坏性的自然灾害的原因。

作者使用一种最近开发的轨迹建模方法，该方法旨在将长期构造运动从每日GNSS时间序列中分离出来，来证明2010年智利的Maule地震（8.8级）和2011年日本的Tohoku-oki地震（9.0级）发生之前，地表位移发生了4~8毫米的逆转，这种逆转持续了几个月，跨越了数千公里。

日本东北部大地震前发生的地表位移反转模型显示，菲律宾海板块先是缓慢滑动，然后突然向下俯冲，其速度之快导致整个日本的粘弹性反弹。

因此，为了更好地理解即将发生的大地震，不仅要考虑板块界面摩擦过程的演化，还要考虑深部俯冲过程的动态边界条件，如亚稳态板块的突然致密化。

▲ Abstract

Megathrust earthquakes are responsible for some of the most devastating natural disasters. Here we use a recently developed trajectory modelling approach that is designed to isolate secular tectonic motions from the daily GNSS time series to show that the 2010 Maule, Chile (moment magnitude 8.8) and 2011 Tohoku-oki, Japan (moment magnitude 9.0) earthquakes were preceded by reversals of 4–8 millimetres in surface displacement that lasted several months and spanned thousands of kilometres. Modelling of the surface displacement reversal that occurred before the Tohoku-oki earthquake suggests an initial slow slip followed by a sudden pulldown of the Philippine Sea slab so rapid that it caused a viscoelastic rebound across the whole of Japan. Therefore, to understand better when large earthquakes are imminent, we must consider not only the evolution of plate interface frictional processes but also the dynamic boundary conditions from deeper subduction processes, such as sudden densification of metastable slab.

Exploring dynamical phase transitions with cold atoms in an optical cavity

光腔中冷原子的动态相变

▲ 作者：Juan A. Muniz, Diego Barberena, Robert J. Lewis-Swan, Dylan J. Young, Julia R. K. Cline, Ana Maria Rey & James K. Thompson

▲ 链接：https://www.nature.com/articles/s41586-020-2224-x

▲ 摘要

光腔中原子和光的相互作用为研究受控环境下的集体（多体）量子物理提供了一种手段。

作者在一个光学腔中使用大约一百万个锶-88原子的集合来模拟一个集体Lipkin-Meshkov-Glick（LMG）模型，这是量子磁性的一个标志性模型，并报告了在这个系统中观察到的不同的物质动力学阶段。该系统允许作者探索动态相变对系统大小、初始状态和其他参数的依赖关系。

这些观测结果可以与相关系统中类似的动力学相联系起来，包括超流氦中的约瑟夫森效应，或原子与固体耦合的极化激元凝聚。该系统本身提供了在光学跃迁中产生在计量上有用的纠缠态的可能性，这可能允许在最先进的原子钟中进行量子增强。

▲ Abstract

Interactions between atoms and light in optical cavities provide a means of investigating collective (many-body) quantum physics in controlled environments. Here, we use an ensemble of about a million strontium-88 atoms in an optical cavity to simulate a collective Lipkin–Meshkov–Glick model, an iconic model in quantum magnetism, and report the observation of distinct dynamical phases of matter in this system. Our system allows us to probe the dependence of dynamical phase transitions on system size, initial state and other parameters. These observations can be linked to similar dynamical phases in related systems, including the Josephson effect in superfluid helium, or coupled atomic and solid-state polariton condensates. The system itself offers potential for generation of metrologically useful entangled states in optical transitions, which could permit quantum enhancement in state-of-the-art atomic clocks.

医学Medicine

An open-source drug discovery platform enables ultra-large virtual screens

开源药物发现平台可实现超大虚拟试验

▲ 作者：Christoph Gorgulla, Andras Boeszoermenyi, Zi-Fu Wang, Haribabu Arthanari, etc.

▲ 链接：https://www.nature.com/articles/s41586-020-2117-z

▲ 摘要

目前，批准一种药物的平均成本为20亿~ 30亿美元，研发时间超过10年。在某种程度上，这是由于临床（前）阶段昂贵和耗时的湿实验、糟糕的初始对应化合物和高磨耗率。

作者描述了高度自动化和通用的开源平台VirtualFlow，它具有完美的缩放行为，能够有效地筛选超大型化合物库。VirtualFlow能够使用各种最强大的扩展程序。

通过使用VirtualFlow，作者准备了一个最大且免费可用的现成的配体库，其中有超过14亿个商业可用的分子。为了证明VirtualFlow的强大功能，作者筛选了超过10亿个化合物，并识别出一组结构多样的分子，它们与亚微摩尔亲和力的KEAP1结合。

其中一种先导抑制剂与纳米级亲和的KEAP1结合，干扰KEAP1与转录因子NRF2之间的相互作用。这说明了VirtualFlow的潜力，它可以访问化学空间的广大区域，并识别与目标蛋白具有高亲和力的分子。

▲ Abstract

On average, an approved drug currently costs US$2–3 billion and takes more than 10 years to develop. In part, this is due to expensive and time-consuming wet-laboratory experiments, poor initial hit compounds and the high attrition rates in the (pre-)clinical phases. Here we describe VirtualFlow, a highly automated and versatile open-source platform with perfect scaling behaviour that is able to prepare and efficiently screen ultra-large libraries of compounds. VirtualFlow is able to use a variety of the most powerful docking programs. Using VirtualFlow, we prepared one of the largest and freely available ready-to-dock ligand libraries, with more than 1.4 billion commercially available molecules. To demonstrate the power of VirtualFlow, we screened more than 1 billion compounds and identified a set of structurally diverse molecules that bind to KEAP1 with submicromolar affinity. One of the lead inhibitors engages KEAP1 with nanomolar affinity and disrupts the interaction between KEAP1 and the transcription factor NRF2. This illustrates the potential of VirtualFlow to access vast regions of the chemical space and identify molecules that bind with high affinity to target proteins.

Action of a minimal contractile bactericidal nanomachine

最小收缩杀菌纳米机器的作用

▲ 作者：Peng Ge, Dean Scholl, Nikolai S. Prokhorov, Z. Hong Zhou, etc.

▲ 链接：https://www.nature.com/articles/s41586-020-2186-z

▲ 摘要

R型细菌素是最小可收缩的纳米机器，有望成为精确的抗生素。作者报告了完整的R2 绿脓杆菌素的收缩前和收缩后状态的原子模型，每个包含10个基因产物的11个独特原子模型的384个亚基。

这些结构的比较表明，绿脓杆菌素收缩期间会发生一系列事件：尾纤维触发基板三丛的横向分离；然后引发一系列事件导致鞘收缩；这种收缩将化学能转化为机械力，推动铁头管穿过细菌细胞表面，杀死细菌。

▲ Abstract

R-type bacteriocins are minimal contractile nanomachines that hold promise as precision antibiotics. Here we report the atomic model of the complete R2 pyocin in its pre-contraction and post-contraction states, each containing 384 subunits of 11 unique atomic models of 10 gene products. Comparison of these structures suggests the following sequence of events during pyocin contraction: tail fibres trigger lateral dissociation of baseplate triplexes; the dissociation then initiates a cascade of events leading to sheath contraction; and this contraction converts chemical energy into mechanical force to drive the iron-tipped tube across the bacterial cell surface, killing the bacterium.

教育Education

Measuring and forecasting progress towards the education-related SDG targets

衡量和预测教育相关的可持续发展目标的进展

▲ 作者：Joseph Friedman, Hunter York, Nicholas Graetz, Lauren Woyczynski, Joanna Whisnant, Simon I. Hay, Emmanuela Gakidou, etc.

▲ 链接：https://www.nature.com/articles/s41586-020-2198-8

▲ 摘要

教育是幸福的一个关键方面，是发展的一个关键指标。可持续发展目标（SDGs）优先考虑教育方面的进展，并将新的重点放在不平等问题上。

作者对一些国家的教育年限分布进行了建模，并使用该模型探索自1970年以来的教育不平等，并预测实现与教育相关的2030年可持续发展目标的进展。

作者分析表明，尽管世界在很大程度上有望在2030年前实现基本普及的初等教育，但中等和高等教育的完成率仍面临巨大挑战。

从全球看，到2018年，上学方面的性别差距已接近消除，但在撒哈拉以南非洲、北非和中东的部分地区，性别差异依然严重。据预测，到2030年，18个国家的女性受教育程度将显著高于男性。全球范围内的教育不平等在2017年达到顶峰，预计到2030年将稳步下降。

▲ Abstract

Education is a key dimension of well-being and a crucial indicator of development. The Sustainable Development Goals (SDGs) prioritize progress in education, with a new focus on inequality. Here we model the within-country distribution of years of schooling, and use this model to explore educational inequality since 1970 and to forecast progress towards the education-related 2030 SDG targets. We show that although the world is largely on track to achieve near-universal primary education by 2030, substantial challenges remain in the completion rates for secondary and tertiary education. Globally, the gender gap in schooling had nearly closed by 2018 but gender disparities remained acute in parts of sub-Saharan Africa, and North Africa and the Middle East. It is predicted that, by 2030, females will have achieved significantly higher educational attainment than males in 18 countries. Inequality in education reached a peak globally in 2017 and is projected to decrease steadily up to 2030.