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Nature,做作周论 27 July 2023, VOL 619, ISSUE 7971

《做作》2023年7月27日，第619卷 ，出书7971期

地舆学Astronomy

Spectroscopic identification of water emission from a main-belt comet

主带彗星水辐射的文导光谱识别

▲ 作者 ：Michael S. P. Kelley, Henry H. Hsieh, Dennis Bodewits, Moha妹妹ad Saki, Geronimo L. Villanueva, Stefanie N. Milam, et al.

▲ 链接  ：

https://www.nature.com/articles/s41586-023-06152-y

▲ 摘要：

主带彗星是位于小行星带的小型太阳系天体，在其克日点通道中一再展现出相似彗星的做作周论行动（即灰尘彗发或者彗尾） ，强烈表明冰升华。出书尽管主带彗星的文导存在象征着小行星带中有尚存的水冰，但尽管用天下上最大的做作周论望远镜妨碍了详尽探测，在这些天体周围仍未发现气体 。出书

钻研组揭示了詹姆斯·韦伯太空望远镜的文导审核服从 
，它清晰地表明 ，做作周论主带彗星238P/Read有一个水蒸气彗发
 ，出书但缺少清晰的文导二氧化碳气体彗发 。该发现表明 ，做作周论Read彗星的出书行动是由水冰升华驱动的 ，这象征着主带彗星与艰深彗星群有着根基的文导差距。

不论Read彗星是否履历了差距的组成情景或者演化史 ，它都不太可能是最近才从外太阳系突入小行星带的 。凭证这些服从，主带彗星彷佛代表了一种挥发性物资样本 ，且这种物资当初在典型彗星的审核以及陨石记实中不代表性，这对于清晰早期太阳系的挥发性物资及其随后演化颇为紧张。

▲ Abstract ：

 Main-belt comets are small Solar System bodies located in the asteroid belt that repeatedly exhibit comet-like activity (that is, dust comae or tails) during their perihelion passages, strongly indicating ice sublimation. Although the existence of main-belt comets implies the presence of extant water ice in the asteroid belt, no gas has been detected around these objects despite intense scrutiny with the world’s largest telescopes. Here we present James Webb Space Telescope observations that clearly show that main-belt comet 238P/Read has a coma of water vapour, but lacks a significant CO2 gas coma. Our findings demonstrate that the activity of comet Read is driven by water–ice sublimation, and implies that main-belt comets are fundamentally different from the general cometary population. Whether or not comet Read experienced different formation circumstances or evolutionary history, it is unlikely to be a recent asteroid belt interloper from the outer Solar System. On the basis of these results, main-belt comets appear to represent a sample of volatile material that is currently unrepresented in observations of classical comets and the meteoritic record, making them important for understanding the early Solar System’s volatile inventory and its subsequent evolution.

物理学Physics

Femtosecond proton transfer in urea solutions probed by X-ray spectroscopy

X射线光谱学探测尿素溶液中的飞秒质子转移

▲ 作者 ：Zhong Yin, Yi-Ping Chang, Tadas Bal?iūnas, Yashoj Shakya, Aleksa Djorovi?, Geoffrey Gaulier, et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06182-6

▲ 摘要 ：

质子转移是水相化学中最根基的使命之一
，也是超快电子以及妄想能源学耦合的典型典型。在飞秒光阴尺度上解耦电子以及核能源学仍是一项难题挑战，特意是在液相 
、生化历程的做作情景中。

钻研组运用台式水窗X射线罗致光谱的配合特色来揭示水溶液中离子化尿素二聚体的飞秒质子转移能源学。借助于重新算量子力学以及份子力学合计，运用X射线罗致光谱的元素特异性以及位点抉择性 ，钻研组揭示了除了质子转移之外
 ，尿素二聚体的后续重排以及电子妄想相关变更若何经由位点抉择性来识别。

这些服从表明 ，平板射流、台式X射线罗致光谱在剖析生物份子零星中溶液相超快能源学方面具备至关大的后劲。

▲ Abstract：

Proton transfer is one of the most fundamental events in aqueous-phase chemistry and an emblematic case of coupled ultrafast electronic and structural dynamics. Disentangling electronic and nuclear dynamics on the femtosecond timescales remains a formidable challenge, especially in the liquid phase, the natural environment of biochemical processes. Here we exploit the unique features of table-top water-window X-ray absorption spectroscopy to reveal femtosecond proton-transfer dynamics in ionized urea dimers in aqueous solution. Harnessing the element specificity and the site selectivity of X-ray absorption spectroscopy with the aid of ab initio quantum-mechanical and molecular-mechanics calculations, we show how, in addition to the proton transfer, the subsequent rearrangement of the urea dimer and the associated change of the electronic structure can be identified with site selectivity. These results establish the considerable potential of flat-jet, table-top X-ray absorption spectroscopy in elucidating solution-phase ultrafast dynamics in biomolecular systems.

能源迷信Energy Science

Accelerating the energy transition towards photovoltaic and wind in China

减速中国向光伏大风能的能源转型

▲ 作者
 ：Yijing Wang, Rong Wang, Katsumasa Tanaka, Philippe Ciais, Josep Penuelas, Yves Balkanski, et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06180-8

▲ 摘要
：

中国到2060年实现碳中以及目的要求将光伏（PV）大风能的发电量从1 PWh/年削减至10~15 PWh/年
。可是 ，凭证可再沉闷力配置装备部署装置的历史速率 ，即最近的高分说率能源零星模子以及基于中国“十四五”能源睁开（CFED）的预料，到2060年，发电量仅能抵达5~9.5 PWh/年。

钻研组表明，经由径自优化部署3844个新专用事业规模的PV大风电场 ，与超低压（UHV）输电以及储能相调以及，并思考到电力负荷的锐敏性以及学习动态 ，PV大风电的发电量可能从9 PWh/年（对于应CFED道路）增至15 PWh/年，伴同着平均减排老本从每一吨二氧化碳（tCO2）97美元降至6美元。

为了实现这一目的
，PV大风能的年化投资应从2020年的770亿美元（之后途度）增至21世纪20年月的1270亿美元，并在21世纪50年月进一步增至4260亿美元/年 。PV大风能的大规模部署可实现配合获益，以削减最贫穷地域居夷易近的支出。

该钻研服从突出了经由建树储能、扩展输电能耐以及调解需要侧电力负荷来降级电力零星的紧张性，以飞腾部署PV大风力发电来实现中国碳中以及的经济老本 。

▲ Abstract：

China’s goal to achieve carbon (C) neutrality by 2060 requires scaling up photovoltaic (PV) and wind power from 1 to 10–15PWh ?year?1. Following the historical rates of renewable installation, a recent high-resolution energy-system model and forecasts based on China’s 14th Five-year Energy Development (CFED), however, only indicate that the capacity will reach 5–9.5 PWh year?1 by 2060. Here we show that, by individually optimizing the deployment of 3,844 new utility-scale PV and wind power plants coordinated with ultra-high-voltage (UHV) transmission and energy storage and accounting for power-load flexibility and learning dynamics, the capacity of PV and wind power can be increased from 9 PWh year?1(corresponding to the CFED path) to 15 PWh year?1, accompanied by a reduction in the average abatement cost from US$97 to US$6 per tonne of carbon dioxide (tCO2). To achieve this, annualized investment in PV and wind power should ramp up from US$77 billion in 2020 (current level) to US$127 billion in the 2020s and further to US$426 billion year?1 in the 2050s. The large-scale deployment of PV and wind power increases income for residents in the poorest regions as co-benefits. Our results highlight the importance of upgrading power systems by building energy storage, expanding transmission capacity and adjusting power load at the demand side to reduce the economic cost of deploying PV and wind power to achieve carbon neutrality in China.

家养智能Artificial Intelligence

 Heat-assisted detection and ranging

热辅助探测以及测距

▲ 作者：Fanglin Bao, Xueji Wang, Shree Hari Sureshbabu, Gautam Sreekumar, Liping Yang, Vaneet Aggarwal, et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06174-6

▲ 摘要
：

机械感知运用先进的传感器来群集周围场景的信息，以实现态势感知。当智能署理数目削减时 ，运用自动声纳、雷达以及激光雷达来增强相机视觉的开始进机械感知面临诸多难题。运用无处不在的热信号，有望扩展感知的新前沿
。

可是，物体及其情景不断地发射以及散射热辐射 ，导致了被称为“重影效应”的无纹理图像。因此，热视觉不受信息损失的特异性限度 ，而对于导航至关紧张的热测距纵然与家养智能（AI）相散漫，也很难实现 。

钻研组提出并试验证明了热辅助探测以及测距（HADAR）可克制重影这一果真挑战，并将其针对于AI增强的热感测妨碍了基准测试。HADAR不光能在黝黑中像白昼同样看到纹理以及深度
，还能感知到RGB或者热视觉之外的纷杂物理属性 ，这为残缺自动以及物理感知的机械感知奠基了根基。

钻研组开拓了HADAR估量实际 ，并处置了其光子散粒噪声极限 ，该极限形貌了基于HADAR的AI功能的信息实际领土 。HADAR在夜间的测距优于热测距 ，其精度可与白昼的RGB平面视觉相媲美。

该自动化HADAR热成像技术在温度精度上抵达了Cramér–Rao领土
，逾越了现有的热成像技术
。该钻研使命带来了一种倾覆性技术，可经由基于HADAR的自主导航以及人机社交来减速第四次工业革命（工业4.0）。

▲ Abstract：

Machine perception uses advanced sensors to collect information about the surrounding scene for situational awareness. State-of-the-art machine perception using active sonar, radar and LiDAR to enhance camera vision faces difficulties when the number of intelligent agents scales up. Exploiting omnipresent heat signal could be a new frontier for scalable perception. However, objects and their environment constantly emit and scatter thermal radiation, leading to textureless images famously known as the ‘ghosting effect’. Thermal vision thus has no specificity limited by information loss, whereas thermal ranging—crucial for navigation—has been elusive even when combined with artificial intelligence (AI). Here we propose and experimentally demonstrate heat-assisted detection and ranging (HADAR) overcoming this open challenge of ghosting and benchmark it against AI-enhanced thermal sensing. HADAR not only sees texture and depth through the darkness as if it were day but also perceives decluttered physical attributes beyond RGB or thermal vision, paving the way to fully passive and physics-aware machine perception. We develop HADAR estimation theory and address its photonic shot-noise limits depicting information-theoretic bounds to HADAR-based AI performance. HADAR ranging at night beats thermal ranging and shows an accuracy comparable with RGB stereovision in daylight. Our automated HADAR thermography reaches the Cramér–Rao bound on temperature accuracy, beating existing thermography techniques. Our work leads to a disruptive technology that can accelerate the Fourth Industrial Revolution (Industry 4.0) with HADAR-based autonomous navigation and human–robot social interactions.

地球迷信Earth Science

Increased occurrences of consecutive La Ni?a events under global warming

全天下变暖下不断拉尼娜使命频率削减

▲ 作者 ：Tao Geng, Fan Jia, Wenju Cai, Lixin Wu, Bolan Gan, Zhao Jing, et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06236-9

▲ 摘要：

大少数厄尔尼诺使命都是偶发性的
，并在一个夏日抵达峰值，而拉尼娜每一每一在厄尔尼诺之后睁开 ，并不断两年或者更持久 。相对于单年拉尼娜，不断拉尼娜的特色是经向西丰姿围更广 ，因此赤道安定洋的热量补给速率较慢
，使冰凉颇为天气不断存在，这对于全天下天气
、生态零星以及农业发生临时影响。不断多年拉尼娜使命的未来变更依然未知。

运用未来温室气体欺压下的天气模子 ，钻研组发现不断拉尼娜使命的频率削减
，规模从低排放天气下的19±11%增至高排放天气下的33±13%，并患上出高排放天气下频率更强的模子间共识 。

在温室变暖的情景下，副热带西南安定洋的均态变暖最大值增强了针对于扰动的地域热力学照应，发生了比20世纪照应厄尔尼诺紧张颇为更北的颇为东风。赤道东安定洋的一个变暖极大值进一步削减了向北更广颇为方式的敏理性  。

较慢的热量补付与向北更广的偏东颇为无关
 ，使患上第一年拉尼娜的冰凉颇为不断不断到第二年拉尼娜 。因此，在史上不断拉尼娜使掷中泛起的极其天气可能在21世纪会更频仍地爆发。

▲ Abstract ：

Most El Ni?o events occur sporadically and peak in a single winter, whereas La Ni?a tends to develop after an El Ni?o and last for two years or longer. Relative to single-year La Ni?a, consecutive La Ni?a features meridionally broader easterly winds and hence a slower heat recharge of the equatorial Pacific, enabling the cold anomalies to persist, exerting prolonged impacts on global climate, ecosystems and agriculture. Future changes to multi-year-long La Ni?a events remain unknown. Here, using climate models under future greenhouse-gas forcings, we find an increased frequency of consecutive La Ni?a ranging from 19 ± 11% in a low-emission scenario to 33 ± 13% in a high-emission scenario, supported by an inter-model consensus stronger in higher-emission scenarios. Under greenhouse warming, a mean-state warming maximum in the subtropical northeastern Pacific enhances the regional thermodynamic response to perturbations, generating anomalous easterlies that are further northward than in the twentieth century in response to El Ni?o warm anomalies. The sensitivity of the northward-broadened anomaly pattern is further increased by a warming maximum in the equatorial eastern Pacific. The slower heat recharge associated with the northward-broadened easterly anomalies facilitates the cold anomalies of the first-year La Ni?a to persist into a second-year La Ni?a. Thus, climate extremes as seen during historical consecutive La Ni?a episodes probably occur more frequently in the twenty-first century.

The social value of offsets

碳减排抵偿的社会价钱

▲ 作者：Ben Groom & Frank Venmans

▲ 链接 ：

https://www.nature.com/articles/s41586-023-06153-x

▲ 摘要：

当初尚不清晰为了抵偿一吨二氧化碳的排放 ，理当在临时以及有危害的抵偿中贮存多少多碳 。钻研组将抵偿社会价钱（SVO）作为反映抵偿不断光阴以及非格外性以及失败危害的碳社会老本的一个清晰部份，其中SVO凭证防止的经济损失来掂量。

SVO反映了临时贮存的价钱，并克制了先前天气迷信以及经济学的短板。SVO与政策相关。假如SVO/老本比逾越替换妄想的效益/老本比 ，则实用的净零政策将搜罗抵偿。SVO提供了一个目的，经由SVO与碳社会老本之最近掂量抵偿与永世碳贮存的等效性 。

钻研组为差距的危害 、持久性以及善象天气提供了等效因子矩阵。经估算患上出一个履历纪律：在50年的光阴里，每一抵偿封存1吨碳 ，就至关于永世封存0.33~0.5吨碳。

等效策略提供了一种用更重大 、易于把守的短期条约取代永世抵偿条约的措施，可用于碳性命周期合成以及碳债务估值，并可作为比力被迫以及合规市场中差距品质抵偿的根基。

▲ Abstract ：

It is unclear how much carbon should be stored in temporary and risky offsets to compensate one ton of CO2 emissions. Here we cast the social value of an offset (SVO), measured in terms of economic damages avoided, as a well-defined fraction of the social cost of carbon reflecting offset duration, and risks of non-additionality and failure. The SVO reflects the value of temporary storage, and overcomes shortcomings in the climate science and economics of previous contributions. The SVO is policy relevant. An efficient net-zero policy will consist of offsets if their SVO/cost ratio exceeds the benefit/cost ratio of alternatives. The SVO yields an indicator of the equivalence of offsets to permanent carbon storage measured by the ratio of the SVO to the social cost of carbon. We provide a matrix of equivalence factors for different risks, permanence and climate scenarios. Estimation yields a rule of thumb: one offset sequestering one ton for 50 years is equivalent to between 0.33 and 0.5 tons permanently locked away. Equivalence offers a means of replacing perpetual offset contracts by simpler, easy to monitor short-term contracts, has applications to carbon life cycle analysis and the valuation of carbon debts, and can be the basis of comparing offsets of different qualities in the voluntary and compliance markets.