Nature, 27 October 2022, Volume 610 Issue 7933
《自然》 2022年10月27日，第610卷7933期
物理学Phyhics
General-relativistic precession in a black-hole binary
黑洞双星中的广义相对论旋进
▲ 作者：Mark Hannam, Charlie Hoy, Jonathan E. Thompson, Aaron Zimmerman, etc.
▲ 链接：
https://www.nature.com/articles/s41586-022-05212-z
▲ 摘要：
自旋诱导轨道进动的一般相对论现象尚未在强场引力中被观测到。双星黑洞（BBH）的引力波观测是主要的候选者，科学家猜测天体物理双星种群包含进动双星。
在一些信号中已经研究了旋进的印记，但在迄今为止由美国和欧洲探测器LIGO和Virgo观测到的84个BBH中，没有任何一个明确识别出轨道旋进。作者报道了LIGO-Virgo-Kagra引力波信号GW200129的强场进动测量。这颗双星的轨道进动速度比以前对双星脉冲星的弱场测量要快10个数量级。
研究者还发现，主黑洞很可能是高度旋转的。根据目前的二元总体估计，类似gw200129的信号极不可能出现，因此对目前许多二元形成模型提出了直接挑战。
▲ Abstract：
The general-relativistic phenomenon of spin-induced orbital precession has not yet been observed in strong-field gravity. Gravitational-wave observations of binary black holes (BBHs) are prime candidates, as we expect the astrophysical binary population to contain precessing binaries. Imprints of precession have been investigated in several signals, but no definitive identification of orbital precession has been reported in any of the 84 BBH observations so far by the Advanced LIGO and Virgo detectors. Here we report the measurement of strong-field precession in the LIGO–Virgo–Kagra gravitational-wave signal GW200129. The binary’s orbit precesses at a rate ten orders of magnitude faster than previous weak-field measurements from binary pulsars. We also find that the primary black hole is probably highly spinning. According to current binary population estimates, a GW200129-like signal is extremely unlikely, and therefore presents a direct challenge to many current binary-formation models.
The time-programmable frequency comb and its use in quantum-limited ranging
时间可编程频率梳及其在量子有限测距中的应用
▲ 作者：Emily D. Caldwell, Laura C. Sinclair, Nathan R. Newbury & Jean-Daniel Deschenes
▲ 链接：
https://www.nature.com/articles/s41586-022-05225-8
▲ 摘要：
经典的自参照频率梳激光器发明二十年后，由于其光输出的刚性间距，在频率、时间和距离计量方面成为无与伦比的标尺。因此，它现在被用于许多需要高带宽和高精度结合的传感应用。然而，其中许多应用都受到了梳状输出固有刚度的权衡的限制，而且操作的灵敏度远远没有受到量子限制。
作者演示了一个灵活的可编程频率梳，其中脉冲时间和相位以阿秒精度进行数字控制。这种敏捷性使其在传感应用中具有量子限制的灵敏度，因为可编程梳可以配置为在脉冲噪声极限下连贯地跟踪微弱返回脉冲序列。为了突出其功能，他们在测距系统中使用了这种可编程梳子，与传统的双梳子系统相比，达到给定精度所需的功率降低了约5000倍。
这使得平均光子每脉冲数的测距为1/77，同时保留了刚性频率梳的全部精度和精度。除了测距和成像，在时间和频率计量、梳基光谱、泵探针实验和压缩传感方面的应用都应该得益于梳脉冲时间和相位的相干控制。
▲ Abstract：
Two decades after its invention, the classic self-referenced frequency comb laser is an unrivalled ruler for frequency, time and distance metrology owing to the rigid spacing of its optical output. As a consequence, it is now used in numerous sensing applications that require a combination of high bandwidth and high precision. Many of these applications, however, are limited by the trade-offs inherent in the rigidity of the comb output and operate far from quantum-limited sensitivity. Here we demonstrate an agile programmable frequency comb where the pulse time and phase are digitally controlled with ±2-attosecond accuracy. This agility enables quantum-limited sensitivity in sensing applications as the programmable comb can be configured to coherently track weak returning pulse trains at the shot-noise limit. To highlight its capabilities, we use this programmable comb in a ranging system, reducing the required power to reach a given precision by about 5,000-fold compared with a conventional dual-comb system. This enables ranging at a mean photon per pulse number of 1/77 while retaining the full accuracy and precision of a rigid frequency comb. Beyond ranging and imaging, applications in time and frequency metrology, comb-based spectroscopy, pump–probe experiments and compressive sensingshould benefit from coherent control of the comb-pulse time and phase.
化学Chemistry
Screening for generality in asymmetric catalysis
不对称催化的一般性筛选
▲ 作者：Corin C. Wagen, Spencer E. McMinn, Eugene E. Kwan & Eric N. Jacobsen
▲ 链接：
https://www.nature.com/articles/s41586-022-05224-9
▲ 摘要：
过去半个世纪，不对称催化领域的研究取得了里程碑式的进展，使手性构建块、药物和自然产物的高效合成成为可能。少数不对称催化反应已被确定，在广泛的底物上显示高选择性；并非巧合的是，这些反应对合成富对映体化合物的方式影响最大。
由于其本质上很难实现加上手性催化剂的识别和优化方式，作者假设底物在不对称催化中的通用性是罕见的。典型的发现活动依赖于单一的模型基质，因此在狭窄的化学空间区域选择高性能。作者提出了一种实用的方法，使用多种模型底物同时选择不对称催化反应中的对映体选择性和通用性。多底物筛选是通过采用汇集样品的超临界流体色谱-质谱进行高通量手性分析来实现的。
当应用于Pictet-Spengler反应时，多底物筛选方法揭示了这一重要转化的一般对映体选择性催化的一个有前途的和意外的先导，它甚至对筛选集之外的底物组合显示了高对映体选择性。
▲ Abstract：
Research in the field of asymmetric catalysis over the past half century has resulted in landmark advances, enabling the efficient synthesis of chiral building blocks, pharmaceuticals and natural products. A small number of asymmetric catalytic reactions have been identified that display high selectivity across a broad scope of substrates; not coincidentally, these are the reactions that have the greatest impact on how enantioenriched compounds are synthesized. We postulate that substrate generality in asymmetric catalysis is rare not simply because it is intrinsically difficult to achieve, but also because of the way chiral catalysts are identified and optimized. Typical discovery campaigns rely on a single model substrate, and thus select for high performance in a narrow region of chemical space. Here we put forth a practical approach for using multiple model substrates to select simultaneously for both enantioselectivity and generality in asymmetric catalytic reactions from the outset. Multisubstrate screening is achieved by conducting high-throughput chiral analyses by supercritical fluid chromatography–mass spectrometry with pooled samples. When applied to Pictet–Spengler reactions, the multisubstrate screening approach revealed a promising and unexpected lead for the general enantioselective catalysis of this important transformation, which even displayed high enantioselectivity for substrate combinations outside of the screening set.
Shape memory in self-adapting colloidal crystals
自适应胶体晶体的形状记忆
▲ 作者：Seungkyu Lee, Heather A. Calcaterra, Sangmin Lee, Wisnu Hadibrata, Byeongdu Lee, EunBi Oh, Koray Aydin, Sharon C. Glotzer & Chad A. Mirkin
▲ 链接：
https://www.nature.com/articles/s41586-022-05232-9
▲ 摘要：
可重构的、机械响应的晶体材料是许多传感、软机器人、能量转换和存储设备的核心部件。晶体材料在各种刺激下容易变形，可恢复变形的程度高度依赖于键的类型。
事实上，对于通过简单的静电相互作用连接在一起的结构，最小的变形是可以容忍的。相比之下，由分子键连接在一起的结构，原则上可以承受更大的变形，更容易恢复到原来的构型。作者研究了用DNA工程制备的多孔胶体晶体的变形特性。这些晶体尺寸大（大于100微米），具有高粘弹性体积分数（超过97%）的体心立方结构。因此，它们可以被压缩成带有褶皱和折痕的不规则形状，值得注意的是，这些变形的晶体在重新水化后，在几秒钟内就会恢复最初形成良好的晶体形态和内部纳米级的秩序。
对于大多数晶体来说，这种压缩和变形会导致永久的、不可逆的损伤。胶体晶体结构的显著变化伴随着显著的可逆光学性质的变化。例如，原始和结构恢复的晶体在紫外可见区表现出近乎完美的宽频吸收，而变形的晶体表现出显著增加的反射（在某些波长下高达50%的入射光），主要是因为它们的折射率和不均匀性的增加。
▲ Abstract：
Reconfigurable, mechanically responsive crystalline materials are central components in many sensing, soft robotic, and energy conversion and storage devices. Crystalline materials can readily deform under various stimuli and the extent of recoverable deformation is highly dependent upon bond type. Indeed, for structures held together via simple electrostatic interactions, minimal deformations are tolerated. By contrast, structures held together by molecular bonds can, in principle, sustain much larger deformations and more easily recover their original configurations. Here we study the deformation properties of well-faceted colloidal crystals engineered with DNA. These crystals are large in size (greater than 100 µm) and have a body-centred cubic (bcc) structure with a high viscoelastic volume fraction (of more than 97%). Therefore, they can be compressed into irregular shapes with wrinkles and creases, and, notably, these deformed crystals, upon rehydration, assume their initial well-formed crystalline morphology and internal nanoscale order within seconds. For most crystals, such compression and deformation would lead to permanent, irreversible damage. The substantial structural changes to the colloidal crystals are accompanied by notable and reversible optical property changes. For example, whereas the original and structurally recovered crystals exhibit near-perfect (over 98%) broadband absorption in the ultraviolet–visible region, the deformed crystals exhibit significantly increased reflection (up to 50% of incident light at certain wavelengths), mainly because of increases in their refractive index and inhomogeneity.
生态学Ecology
Global hotspots for soil nature conservation
全球土壤自然保护热点
▲ 作者：Carlos A. Guerra, Miguel Berdugo, David J. Eldridge, Manuel Delgado-Baquerizo, etc.
▲ 链接：
https://www.nature.com/articles/s41586-022-05292-x
▲ 摘要：
土壤是所有陆地生态系统的基础。然而，与植物和动物不同的是，目前仍缺乏对土壤自然保护热点的全球评估。这妨碍了人们为支持土壤系统的多个维度（从土壤生物多样性到生态系统服务）确定自然保护优先事项的能力。
为了确定土壤自然保护的全球热点，作者进行了一项全球实地调查，包括对来自所有大陆的615个表土复合样本的生物多样性（古生菌、细菌、真菌、原生生物和无脊椎动物）和功能（对6种生态系统服务至关重要）的观察。
他们发现，土壤的每个不同生态维度——即物种丰富度、群落差异性和生态系统服务，在地球上不同的地区达到峰值，并与不同的环境因子相关。温带生态系统的物种丰富度最高，而热带生态系统的群落差异最高，较冷的高纬度生态系统是生态系统服务的热点。
这些发现突出了同时保护土壤的多个生态维度所涉及的复杂性。研究进一步表明，大多数这些热点地区没有被保护区充分覆盖（超过70%），在几种全球变化情景的背景下很容易受到影响。作者对土壤自然保护重点的全球评估，强调了考虑土壤生物多样性和生态系统服务的多维度，为子孙后代保护土壤的重要性。
▲ Abstract：
Soils are the foundation of all terrestrial ecosystems. However, unlike for plants and animals, a global assessment of hotspots for soil nature conservation is still lacking. This hampers our ability to establish nature conservation priorities for the multiple dimensions that support the soil system: from soil biodiversity to ecosystem services. Here, to identify global hotspots for soil nature conservation, we performed a global field survey that includes observations of biodiversity (archaea, bacteria, fungi, protists and invertebrates) and functions (critical for six ecosystem services) in 615 composite samples of topsoil from a standardized survey in all continents. We found that each of the different ecological dimensions of soils—that is, species richness (alpha diversity, measured as amplicon sequence variants), community dissimilarity and ecosystem services—peaked in contrasting regions of the planet, and were associated with different environmental factors. Temperate ecosystems showed the highest species richness, whereas community dissimilarity peaked in the tropics, and colder high-latitudinal ecosystems were identified as hotspots of ecosystem services. These findings highlight the complexities that are involved in simultaneously protecting multiple ecological dimensions of soil. We further show that most of these hotspots are not adequately covered by protected areas (more than 70%), and are vulnerable in the context of several scenarios of global change. Our global estimation of priorities for soil nature conservation highlights the importance of accounting for the multidimensionality of soil biodiversity and ecosystem services to conserve soils for future generations.
Comprehensive evidence implies a higher social cost of CO2
综合证据表明二氧化碳的更高社会成本
▲ 作者：Kevin Rennert, Frank Errickson, Brian C. Prest, Lisa Rennels, Richard G. Newell, David Anthoff, etc.
▲ 链接：
https://www.nature.com/articles/s41586-022-05224-9
▲ 摘要：
二氧化碳的社会成本（SC-CO2）衡量每增加一吨二氧化碳排放对社会造成的破坏的货币化价值，是影响气候政策的一个关键指标。美国国家科学、工程和医学科学院（NASEM)）2017年的一份报告强调，目前的SC-CO2估算不再反映最新研究。
该报告提出了一系列建议，以改善SC-CO2估算的科学基础、透明度和不确定性特征。作者研究表明，改进的概率社会经济预测、气候模型、损害函数和贴现方法共同反映了理论上一致的风险估值，大大提高了SC-CO2的估值。他们首选的平均SC-CO2估值为每吨二氧化碳185美元，短期无风险贴现率为2%，比美国政府目前每吨二氧化碳51美元的估值高出3.6倍。
作者表示。该评估以完全响应NASEM近期建议的方式，在新的开源温室气体影响值估算（GIVE）模型中纳入了SC-CO2估算的所有组成部分的最新科学理解。与目前用于政策评估的估计数相比，此次研究中更高的SC-CO2值大大增加了温室气体缓解的估计效益，从而增加了更严格的气候政策的预期净效益。
▲ Abstract：
The social cost of carbon dioxide (SC-CO2) measures the monetized value of the damages to society caused by an incremental metric tonne of CO2 emissions and is a key metric informing climate policy. A 2017 report by the US National Academies of Sciences, Engineering, and Medicine1 (NASEM) highlighted that current SC-CO2 estimates no longer reflect the latest research. The report provided a series of recommendations for improving the scientific basis, transparency and uncertainty characterization of SC-CO2 estimates. Here we show that improved probabilistic socioeconomic projections, climate models, damage functions, and discounting methods that collectively reflect theoretically consistent valuation of risk, substantially increase estimates of the SC-CO2. Our preferred mean SC-CO2 estimate is $185 per tonne of CO2 ($44–$413 per tCO2: 5%–95% range, 2020 US dollars) at a near-term risk-free discount rate of 2%, a value 3.6 times higher than the US government’s current value of $51 per tCO2. Our estimates incorporate updated scientific understanding throughout all components of SC-CO2 estimation in the new open-source Greenhouse Gas Impact Value Estimator (GIVE) model, in a manner fully responsive to the near-term NASEM recommendations. Our higher SC-CO2 values, compared with estimates currently used in policy evaluation, substantially increase the estimated benefits of greenhouse gas mitigation and thereby increase the expected net benefits of more stringent climate policies.
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