编译 | 李言

Nature, 22 DEC 2023, Volume 382 Issue 6677

《自然》, 2023年12月22日，第382卷，6677期

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材料科学Materials Science

Biomimetic, knittable aerogel fiber for thermal insulation textile

用于保温纺织品的仿生针织气凝胶纤维

▲ 作者：MINGRUI WU, ZIYU SHAO et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adj8013

▲ 摘要：

气凝胶被认为是一种理想的隔热材料。然而，由于易碎性和交叉口的可加工性，它们在纺织品中的应用受到了很大的限制。我们通过在气凝胶纤维中包裹一层模仿北极熊毛发核—壳结构的可拉伸层来克服这些问题。

尽管其内部孔隙率超过90%，但我们的纤维可拉伸至1000%的应变，与传统的气凝胶纤维相比，有了很大的提高。用我们的纤维编织的毛衣厚度只有羽绒制品的五分之一，但性能却相差无几。我们这种纤维的策略为开发多功能气凝胶纤维和纺织品提供了丰富的可能性。

▲ Abstract：

Aerogels have been considered as an ideal material for thermal insulation. Unfortunately, their application in textiles is greatly limited by their fragility and poor processability. We overcame these issues by encapsulating the aerogel fiber with a stretchable layer, mimicking the core-shell structure of polar bear hair. Despite its high internal porosity over 90%, our fiber is stretchable up to 1000% strain, which is greatly improved compared with that of traditional aerogel fibers (~2% strain). In addition to its washability and dyeability, our fiber is mechanically robust, retaining its stable thermal insulation property after 10,000 stretching cycles (100% strain). A sweater knitted with our fiber was only one-fifth as thick as down, with similar performance. Our strategy for this fiber provides rich possibilities for developing multifunctional aerogel fibers and textiles.

信息技术Information Technology

Are cryptocurrencies currencies? Bitcoin as legal tender in El Salvador

加密货币是货币吗？比特币在萨尔瓦多成为法定货币

▲ 作者：FERNANDO ALVAREZ, DAVID ARGENTE et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.add2844

▲ 摘要：

货币的基本特征是一种交换媒介。我们的研究探讨了作为第一个将比特币定为法定货币的国家，加密货币在萨尔瓦多日常交易中使用的潜力。政府的大力推动促进了“Chivo钱包”的出现，这是一种与中央银行数字货币（CBDCs）共享功能的数字钱包，可以用来交易比特币和美元。

通过对全国1800个家庭的面对面调查和包含所有Chivo钱包交易的区块链数据，我们记录了数字支付和比特币使用率低且不断下降的模式。

隐私和安全问题是主要的使用障碍，这涉及到以匿名为核心的加密货币和CBDCs的政策争议。此外，我们估计了Chivo钱包的使用成本和使用者之间的关系。

▲ Abstract：

A currency’s essential feature is to be a medium of exchange. This study explores the potential of cryptocurrencies to be used in daily transactions in El Salvador, the first country to make bitcoin legal tender. The government’s “big push” introduced “Chivo Wallet,” a digital wallet sharing features with Central Bank Digital Currencies (CBDCs), with perks to use it for trading bitcoins and US dollars. Through a nationally representative, face-to-face survey of 1800 households and blockchain data encompassing all Chivo Wallet transactions, we document a pattern of low and decreasing usage of digital payments and bitcoin. Privacy and security concerns are key adoption barriers, which speaks to a policy debate on crypto and CBDCs with anonymity at its core. Additionally, we estimate Chivo Wallet’s adoption cost and complementarities among adopters.

化学Chemistry

Autonomous, multiproperty-driven molecular discovery: From predictions to measurements and back

多属性驱动的分子自主发现：从预测到测算的回顾

▲ 作者：BRENT A. KOSCHER, RICHARD B. CANTY et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adi1407

▲ 摘要：

吸收波长、亲脂性和光氧化稳定性，我们展示了染料类分子的两个案例研究。在第一项研究中，该平台通过三次分子设计—制造—测试—分析循环的自动迭代实验实现了294个未报道的分子，同时探索了4种很少报道的支架的结构—功能空间。

在每次迭代中，引导探索的性质预测模型通过多步合成和多种反应，学习了不同支架衍生物的结构—性质空间。第二项研究利用在探索化学空间和以往研究的分子上训练的性质模型，在轻度探索的结构—性质空间中发现了9个表现最好的分子。

▲ Abstract：

We demonstrated two case studies on dye-like molecules, targeting absorption wavelength, lipophilicity, and photooxidative stability. In the first study, the platform experimentally realized 294 unreported molecules across three automatic iterations of molecular design-make-test-analyze cycles while exploring the structure-function space of four rarely reported scaffolds. In each iteration, the property prediction models that guided exploration learned the structure-property space of diverse scaffold derivatives, which were realized with multistep syntheses and a variety of reactions. The second study exploited property models trained on the explored chemical space and previously reported molecules to discover nine top-performing molecules within a lightly explored structure-property space.

社会学Sociology

Highlighting health consequences of racial disparities sparks support for action

强调种族差异对健康的影响，可以激发对行动的支持

▲ 作者：RIANA M. BROWN, PIA DIETZE et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adh4262

▲ 摘要：

种族差异在美国生活的许多重要领域显现，包括就业、健康和人际交往。例如，三分之一的黑人儿童生活在贫困中（白人儿童则是九分之一），而且，美国黑人的平均寿命比白人少四年。

哪种差距更有可能激发减少差距的努力？我们发现，相对于经济，强调与健康相关结果的差异会刺激更多的社交媒体参与和对缓解差异政策的支持。

此外，与基于经济或归属的差异相比，阅读有关种族健康差异的文章会引起对行动的更多支持。出现这种情况的部分原因是，人们认为健康上的差距违反了神圣的道德价值观，这加剧了人们不公正的感觉。这项研究阐明了种族不平等的哪些表现形式最有可能促使美国人采取行动。

▲ Abstract：

Racial disparities arise across many vital areas of American life, including employment, health, and interpersonal treatment. For example, one in three Black children lives in poverty (versus one in nine white children), and, on average, Black Americans live four fewer years compared with white Americans. Which disparity is more likely to spark reduction efforts We find that highlighting disparities in health-related (versus economic) outcomes spurs greater social media engagement and support for disparity-mitigating policy. Further, reading about racial health disparities elicits greater support for action (e.g., protesting) compared with economic- or belonging-based disparities. This occurs in part because people view health disparities as violating morally sacred values, which enhances perceived injustice. This work elucidates which manifestations of racial inequality are most likely to prompt Americans to action.

地球科学Earth Science

Genomic evidence for West Antarctic Ice Sheet collapse during the Last Interglacial

末次间冰期南极西部冰盖崩塌的基因组证据

▲ 作者：SALLY C. Y. LAU, NERIDA G. WILSON et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ade0664

▲ 摘要：

在未来的气候轨迹下，以海洋为基础的南极西部冰盖（WAIS）被认为很容易发生不可逆转的崩塌，其临界点可能在联合国《巴黎协定》规定的1.5°C至2°C的减缓变暖情景范围内。

对过去类似温暖气候期间冰损失的了解可以解决这种不确定性，例如末次间冰期，当时全球海平面比今天高5至10米，全球平均气温比工业化前水平高0.5°至1.5°C。

利用一组环—南极章鱼的全基因组单核苷酸多态性，我们发现只有在WAIS完全崩溃的情况下，才有可能出现持久性、历史性的基因流信号。我们的研究结果提供了首个经验证据，表明即使在严格的气候减缓情景下，也可能达到WAIS损失的临界点。

▲ Abstract：

The marine-based West Antarctic Ice Sheet (WAIS) is considered vulnerable to irreversible collapse under future climate trajectories, and its tipping point may lie within the mitigated warming scenarios of 1.5° to 2°C of the United Nations Paris Agreement. Knowledge of ice loss during similarly warm past climates could resolve this uncertainty, including the Last Interglacial when global sea levels were 5 to 10 meters higher than today and global average temperatures were 0.5° to 1.5°C warmer than preindustrial levels. Using a panel of genome-wide, single-nucleotide polymorphisms of a circum-Antarctic octopus, we show persistent, historic signals of gene flow only possible with complete WAIS collapse. Our results provide the first empirical evidence that the tipping point of WAIS loss could be reached even under stringent climate mitigation scenarios.

Learning skillful medium-range global weather forecasting

熟练的全球中期天气预报

▲ 作者：REMI LAM, ALVARO SANCHEZ-GONZALEZ et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adi2336

▲ 摘要：

在这里，我们介绍GraphCast，这是一种基于机器学习、直接从再分析数据中训练的方法。它可以在一分钟内以0.25°的分辨率预测未来10天全球数百个天气变量。

在1380个验证目标中，GraphCast在90%的验证目标中显著优于目前最精确的操作确定性系统，它可以进行更高质量的严重事件预测，包括热带气旋跟踪、大气河和极端温度。GraphCast的出现是准确和高效天气预报的重要进步，有助于实现机器学习对复杂动态系统建模的愿景。

▲ Abstract：

Here, we introduce GraphCast, a machine learning–based method trained directly from reanalysis data. It predicts hundreds of weather variables for the next 10 days at 0.25° resolution globally in under 1 minute. GraphCast significantly outperforms the most accurate operational deterministic systems on 90% of 1380 verification targets, and its forecasts support better severe event prediction, including tropical cyclone tracking, atmospheric rivers, and extreme temperatures. GraphCast is a key advance in accurate and efficient weather forecasting and helps realize the promise of machine learning for modeling complex dynamical systems.