《科学》（20230505出版）一周论文导读

Science,5 MAY 2023, Volume 380 Issue 6644

《科学》2022年5月5日，第380卷，6644期

天文学Astronomy

Inspiraling streams of enriched gas observed around a massive galaxy 11 billion years ago

在距今110亿年的巨大星系周围观测的丰富气体流

▲ 作者：SHIWU ZHANG, ZHENG CAI et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.abj9192

▲ 摘要：

星系中的恒星是由星系间吸积气体而形成的。模拟表明，气体的循环——从此前的星系中喷出的气体的再吸积——可以解释早期宇宙中恒星的形成。

我们观察到一个红移2.3的大质量星系周围的气体，并探测到了从星系延伸100千秒差距的中性氢、氦和电离碳的放射线。这些环绕星系的气体的动理学与循环流是一致的。

碳丰度检测表示，这种气体富含比氦更重的元素，这些元素之前是从星系中喷射出来的。我们认为这些结果可以被认为是高红移星系组合期间气体再循环的证据。

▲ Abstract：

Stars form in galaxies, from gas that has been accreted from the intergalactic medium. Simulations have shown that recycling of gas—the reaccretion of gas that was previously ejected from a galaxy—could sustain star formation in the early Universe. We observe the gas surrounding a massive galaxy at redshift 2.3 and detect emission lines from neutral hydrogen, helium, and ionized carbon that extend 100 kiloparsecs from the galaxy. The kinematics of this circumgalactic gas is consistent with an inspiraling stream. The carbon abundance indicates that the gas had already been enriched with elements heavier than helium, previously ejected from a galaxy. We interpret the results as evidence of gas recycling during high-redshift galaxy assembly.

机器人科学Robotics

Multilegged matter transport: A framework for locomotion on noisy landscapes

多足机器人物质运输：在嘈杂环境中运动的框架

▲ 作者：BAXI CHONG, JUNTAO HE, DANIEL SOTO et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ade4985

▲ 摘要：

虽然有轮车辆或足式机器人在道路或铁路等工程环境中可以保证物质的运输，但在倒塌建筑物或农田等复杂环境中的运动预测仍然具有挑战性。信息传输原理允许信号在“噪声”通道上进行可靠传输。

受此启发，我们开发了一个“物质运输”框架，证明了非惯性运动可以在嘈杂的褶皱景观（运动尺寸尺度上的异质性）中产生。实验证明，在不需要传感和控制的情况下，以串联足式机器人的形式提供足够的空间冗余，可以促成在这种地形上的可靠运输。

通信理论的进一步类比，加上步态（编码）和基于传感器的反馈控制（错误检测和纠正）的进步，可以在复杂的地面动力学环境中实现敏捷运动。

▲ Abstract：

Whereas the transport of matter by wheeled vehicles or legged robots can be guaranteed in engineered landscapes such as roads or rails, locomotion prediction in complex environments such as collapsed buildings or crop fields remains challenging. Inspired by the principles of information transmission, which allow signals to be reliably transmitted over “noisy” channels, we developed a “matter-transport” framework that demonstrates that noninertial locomotion can be provably generated over noisy rugose landscapes (heterogeneities on the scale of locomotor dimensions). Experiments confirm that sufficient spatial redundancy in the form of serially connected legged robots leads to reliable transport on such terrain without requiring sensing and control. Further analogies from communication theory coupled with advances in gaits (coding) and sensor-based feedback control (error detection and correction) can lead to agile locomotion in complex terradynamic regimes.

地球科学Geoscience

Atmospheric nourishment of global ocean ecosystems

全球海洋生态系统的大气营养

▲ 作者：T. K. WESTBERRY, M. J. BEHRENFELD et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.abq5252

▲ 摘要：

在广阔的开放海洋上，浮游植物在阳光照射的表层生长所需的重要营养物质大部分是通过深海的物理运输提供的，但也有一些来自沙漠尘埃的大气沉积。在全球范围内，沙尘介导的对海洋表层生态系统影响的程度和幅度一直难以估计。

在这项研究中，我们使用全球卫星海洋水色产品来展示在不同的浮游植物营养条件连续体中对大气尘埃沉积的广泛响应。被观测到的响应因地区而异，一些地区的浮游植物生物量发生了实质性变化，而在其他地区，这种响应反映了生理状态或健康状况的变化。气候驱动的大气气溶胶变化将改变这种营养来源的相对重要性。

▲ Abstract：

Over the vast open ocean, vital nutrients for phytoplankton growth in the sunlit surface layer are largely provided through physical transport from deep waters, but some nutrients are also provided through atmospheric deposition of desert dust. The extent and magnitude of dust-mediated effects on surface ocean ecosystems have been difficult to estimate globally. In this work, we use global satellite ocean color products to demonstrate widespread responses to atmospheric dust deposition across a diverse continuum of phytoplankton nutritional conditions. The observed responses vary regionally, with some areas exhibiting substantial changes in phytoplankton biomass, whereas in other areas, the response reflects a change in physiological status or health. Climate-driven changes in atmospheric aerosols will alter the relative importance of this nutrient source.

材料科学Material Science

Topological kinetic crossover in a nanomagnet array

纳米磁体阵列的拓扑动力学交叉

▲ 作者：XIAOYU ZHANG, GRANT FITEZ et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.add6575

▲ 摘要：

遍历动理学可能受到系统拓扑结构的限制，是平衡热力学的关键。我们研究了一个可以约束明显影响磁矩行为的模型纳米磁阵列。在这个系统中，磁激励连接成热活跃的一维弦，其运动可以实时成像。

在高温环境下，我们的数据显示了串的合并、断裂和重新连接，导致系统在不同的拓扑结构之间转换。在交叉温度以下，弦的运动由长度和形状的简单变化所影响。在这种低温状态下，系统是能量稳定的，因为它无法探索所有可能的拓扑构型。这种动理学交叉提出了拓扑破缺遍历性和有限平衡的一般概念。

▲ Abstract：

Ergodic kinetics, which are critical to equilibrium thermodynamics, can be constrained by a system’s topology. We studied a model nanomagnetic array in which such constraints visibly affect the behavior of the magnetic moments. In this system, magnetic excitations connect into thermally active one-dimensional strings whose motion can be imaged in real time. At high temperatures, our data showed the merging, breaking, and reconnecting of strings, resulting in the system transitioning between topologically distinct configurations. Below a crossover temperature, the string motion is dominated by simple changes in length and shape. In this low-temperature regime, the system is energetically stable because of its inability to explore all possible topological configurations. This kinetic crossover suggests a generalizable conception of topologically broken ergodicity and limited equilibration.

生物学Biology

A chemical defense deters cannibalism in migratory locusts

化学防御手段防止迁徙蝗虫的同类相食行为

▲ 作者：HETAN CHANG, SINA CASSAU et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ade6155

▲ 摘要：

许多动物以同类相食来补充自己的饮食。在迁徙蝗虫密集的种群中，同类相食很普遍。我们发现，在拥挤环境中，蝗虫会产生一种名为苯乙腈的抗同类信息素。同类相食的程度和苯乙腈的产量都是密度相关和共变的。我们确定了检测苯乙腈的嗅觉受体，并使用基因组编辑使该受体失效，从而消除了负面的行为反应。

我们还灭活了产生苯乙腈的基因，并表明缺乏这种化合物的蝗虫失去了它的保护，会更频繁地暴露于这种种内捕食。由此，我们揭示了一种基于特定产生的气味的反同类相食特征。该系统很可能在蝗虫种群生态学中具有重要意义，因此我们的结果可能为控制蝗虫提供可能。

▲ Abstract：

Many animals engage in cannibalism to supplement their diets. Among dense populations of migratory locusts, cannibalism is prevalent. We show that under crowded conditions, locusts produce an anticannibalistic pheromone called phenylacetonitrile. Both the degree of cannibalism and the production of phenylacetonitrile are density dependent and covary. We identified the olfactory receptor that detects phenylacetonitrile and used genome editing to make this receptor nonfunctional, thereby abolishing the negative behavioral response. We also inactivated the gene underlying phenylacetonitrile production and show that locusts that lack this compound lose its protection and are more frequently exposed to intraspecific predation. Thus, we reveal an anticannibalistic feature built on a specifically produced odor. The system is very likely to be of major importance in locust population ecology, and our results might therefore provide opportunities in locust management.

社会学Sociology

Where and with whom does a brief social-belonging intervention promote progress in college?

短期社会归属感干预如何提高大学完成情况

▲ 作者：GREGORY M. WALTON, MARY C. MURPHY et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ade4420

▲ 摘要：

解决学生的归属感问题可能是缓解不平等的一个有效方式。但是社会归属感干预是如何起效的呢？在此，我们报告了一项团队科学随机对照实验，涉及来自22所不同学校的26911名学生。

结果显示，在大学入学前（在30分钟内）在线进行社会归属感干预，提高了全日制学生完成第一年学业的概率，尤其是在那些有更低完成率历史的群体中。大学环境也很重要：只有当学生群体有归属机会时，干预才能起效。这项研究发展了理解学生身份和背景如何与干预相互作用的方法。

研究同时显示，一项成本、可扩展的干预措施可以对美国749所4年制大学产生普遍的影响。

▲ Abstract：

A promising way to mitigate inequality is by addressing students’ worries about belonging. But where and with whom is this social-belonging intervention effective? Here we report a team-science randomized controlled experiment with 26,911 students at 22 diverse institutions. Results showed that the social-belonging intervention, administered online before college (in under 30 minutes), increased the rate at which students completed the first year as full-time students, especially among students in groups that had historically progressed at lower rates. The college context also mattered: The intervention was effective only when students’ groups were afforded opportunities to belong. This study develops methods for understanding how student identities and contexts interact with interventions. It also shows that a low-cost, scalable intervention generalizes its effects to 749 4-year institutions in the United States.

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