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发布日期：2024-09-15 作者：开博
Nature, 29 August 2024, Volume 632 Issue 8027
《天然》2024年8月29日，第632卷，8027期
地球科学Earth Science
Earth’s ambipolar electrostatic field and its role in ion escape to space
地球的双极静电场和其在离子逃逸到太空中饰演的脚色
▲ 作者：Glyn A. Collinson, Alex Glocer et al.
▲ 链接：https://www.nature.com/articles/s41586-024-07480-3
▲摘要：
在此，我们陈述在250千米至768千米规模内，仅由电离层电子向外压力发生的行星静电场（E∥⊕=1.09±0.17μVm?1）存在+0.55±0.09V的电位降。我们的尝试注解，地球的双极静电场节制着极地电离层的布局，将规模高度晋升至271%。
我们认为这将使冷O+离子向磁层的供给增添了3800%以上，此中波粒彼此感化等其他机制可以加热并进一步加快它们到达逃逸速度。地球的静电场足够壮大到驱动极地风，而且多是主导年夜部门磁层的冷氢离子群的发源。
▲ Abstract：
Here we report the existence of a +0.55?±?0.09?V electric potential drop between 250?km and 768?km from a planetary electrostatic field (E∥⊕?=?1.09?±?0.17?μV?m?1) generated exclusively by the outward pressure of ionospheric electrons. We experimentally demonstrate that the ambipolar field of Earth controls the structure of the polar ionosphere, boosting the scale height by 271%. We infer that this increases the supply of cold O+ ions to the magnetosphere by more than 3,800%, in which other mechanisms such as wave–particle interactions can heat and further accelerate them to escape velocity. The electrostatic field of Earth is strong enough by itself to drive the polar wind and is probably the origin of the cold H+ ion population1 that dominates much of the magnetosphere.
天文学Astronomy
A nebular origin for the persistent radio emission of fast radio bursts
快速射电暴延续射电发射的星云发源
▲ 作者：Gabriele Bruni, Luigi Piro et al.
▲ 链接：https://www.nature.com/articles/s41586-024-07782-6
▲ 摘要：
在此，我们陈述在距离413Mpc的反复快速射电暴源FRB20201124A相干的第三个亮度较低的延续射电源的检测，这年夜年夜扩大了猜测关系到低亮度—低法拉第扭转丈量规模（ 1000?rad?m?2）。
在较低的法拉第扭转丈量值下，预期的射电光度低在现今射电千里镜的探测极限。这些发现撑持了如许一种不雅点，即到今朝为止不雅测到的延续射电源是由快速射电暴情况中的星云发生的，而且因为较弱的磁离子介质，具有低法拉第扭转丈量的快速射电暴可能不会显示出延续射电源。
这与将年青的磁星作为快速射电暴中间引擎的模子根基一致。在该模子中，四周的电离星云或双星系统中的彼此感化激波为延续的射电源供给动力。
▲ Abstract：
Here we report the detection of a third, less luminous persistent radio source associated with the repeating FRB source FRB?20201124A at a distance of 413?Mpc, substantially expanding the predicted relation into the low luminosity–low Faraday rotation measure regime ( 1,000?rad?m?2). At lower values of the Faraday rotation measure, the expected radio luminosity falls below the limit-of-detection threshold for present-day radio telescopes. These findings support the idea that the persistent radio sources observed so far are generated by a nebula in the FRB environment and that FRBs with low Faraday rotation measure may not show a persistent radio source because of a weaker magneto-ionic medium. This is generally consistent with models invoking a young magnetar as the central engine of the FRB, in which the surrounding ionized nebula—or the interacting shock in a binary system—powers the persistent radio source.
工程学Engineering
Passive wing deployment and retraction in beetles and flapping microrobots
甲虫和扑翼微型机械人同党的被动睁开和收拢
▲ 作者：Hoang-Vu Phan, Hoon Cheol Park Dario Floreano
▲ 链接：https://www.nature.com/articles/s41586-024-07755-9
▲摘要：
在此，我们展现了犀金龟可以绝不吃力地睁开它们的后翅，而不需要肌肉勾当。我们展现了打开鞘翅会将像弹簧一样的后翅部门从身体上释放出来，从而为随后的拍感动作供给所需的空间，从而使后翅进入飞翔位置。
飞翔竣事后，犀金龟可以操纵鞘翅鞭策后翅回到静止位置，进一步撑持了被动睁开的假定。我们用一个能被动睁开同党进行不变可控飞翔、并在着陆时整洁地收回同党的扑翼微型机械人验证了这一假定，展现了一种简单而有用的设计类虫豸飞翔微型机械的方式。
▲ Abstract：
Here we demonstrate that rhinoceros beetles can effortlessly deploy thei开博体育r hindwings without necessitating muscular activity. We show that opening the elytra triggers a spring-like partial release of the hindwings from the body, allowing the clearance needed for the subsequent flapping motion that brings the hindwings into the flight position. After flight, the beetle can use the elytra to push the hindwings back into the resting position, further strengthening the hypothesis of passive deployment. We validated the hypothesis using a flapping microrobot that passively deployed its wings for stable, controlled flight and retracted them neatly upon landing, demonstrating a simple, yet effective, approach to the design of insect-like flying micromachines.
化学Chemistry
Methyl-reducing methanogenesis by a thermophilic culture of Korarchaeia
高丽菌嗜热培育的甲基还原甲烷生成
▲ 作者：Viola Krukenberg, Anthony J. Kohtz, Zackary J. Jay Roland Hatzenpichler
▲ 链接：https://www.nature.com/articles/s41586-024-07829-8
▲ 摘要：
在此，我们展现了热变形门（TACK超门）中Korarchaeia谱系成员的产甲烷发展。经由过程对washburnenis候选甲烷脱硫菌LCB3的富集培育，我们对代谢活性和同位素示踪剂转化进行了丈量，以证实以氢为电子供体的甲醇还原为甲烷。
对古菌环基因组和转录组的阐发揭露了与甲烷生成相干的能量守恒路子的怪异润色，包罗介入氢和硫代谢的酶复合物。这一新的古细菌群的培育和判定对更深切地评估产甲烷菌的多样性、心理和生物化学相当主要。
▲ Abstract：
Here we show methanogenic growth by a member of the lineage Korarchaeia within the phylum Thermoproteota (TACK superphylum). Following enrichment cultivation of ‘Candidatus Methanodesulfokora washburnenis’ strain LCB3, we used measurements of metabolic activity and isotope tracer conversion to demonstrate methanol reduction to methane using hydrogen as an electron donor. Analysis of the archaeon’s circular genome and transcriptome revealed unique modifications in the energy conservation pathways linked to methanogenesis, including enzyme complexes involved in hydrogen and sulfur metabolism. The cultivation and characterization of this new group of archaea is critical for a deeper evaluation of the diversity, physiology and biochemistry of methanogens.
生物学Biology
The Space Omics and Medical Atlas (SOMA) and internationalastronaut biobank
空间组学和医学图谱（SOMA）与国际宇航员生物库
▲ 作者：Eliah G. Overbey, JangKeun Kim et al.
▲ 链接：https://www.nature.com/articles/s41586-024-07639-y
▲ 摘要：
在此，我们介绍了空间组学和医学图谱（SOMA）。这是一个集成的数据和样本存储库，包括来自分歧使命的临床、细胞和多组学研究资料，包罗NASA双胞胎研究、JAXA CFE研究、SpaceX灵感4号机组和Axiom和Polaris。SOMA资本代表了公然可用的人类空间组学数据增添了10倍以上，康奈尔航空航天医学生物库供给了匹配的样本。
该图谱包罗普遍的份子和心理图谱，包罗基因组学、表不雅基因组学、转录组学、卵白质组学、代谢组学和微生物组数据集，揭露了跨使命的一些一致特点，包罗细胞因子转移、端粒延长和基因表达转变，和使命特异性份子反映和与同源、组织特异性小鼠数据集的链接。
▲ Abstract：
Here we present the Space Omics and Medical Atlas (SOMA), an integrated data and sample repository for clinical, cellular and multi-omic research profiles from a diverse range of missions, including the NASA Twins Study, JAXA CFE study, SpaceX Inspiration4 crew, Axiom and Polaris. The SOMA resource represents a more than tenfold increase in publicly available human space omics data, with matched samples available from the Cornell Aerospace Medicine Biobank. The Atlas includes extensive molecular and physiological profiles encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics and microbiome datasets, which reveal some consistent features across missions, including cytokine shifts, telomere elongation and gene expression changes, as well as mission-specific molecular responses and links to orthologous, tissue-specific mouse datasets.
Molecular and physiological changes in the SpaceX Inspiration4 civilian crewSpaceX Inspiration4
平易近用机组人员的份子和心理转变
▲ 作者：Christopher W. Jones, Eliah G. Overbey et al.
▲ 链接：https://www.nature.com/articles/s41586-024-07648-x
▲摘要：
在此，我们陈述了针对为期3天太空飞翔使命的首要发现。该使命引发了普遍的心理和应激反映、以眼球错位为指标的神经前庭转变，和神经认知功能的改变，此中一些与持久太空飞翔相匹配，但几近所有这些与返回地球后的基线（飞翔前）没有差别。
整体而言，这些初步平易近用航天数据注解，短时间飞翔使命不会造成重年夜健康风险，并且在剖解、细胞、心理和认知程度上丈量人体对航天的最早顺应阶段供给了丰硕的机遇。最后，这些方式和成果为成立一个开放的、快速扩大的宇航员生物医学数据库奠基了根本，该数据库可觉得私家和当局帮助的太空使命供给对策开辟信息。
▲ Abstract：
Here we report the primary findings from the 3-day spaceflight mission, which induced a broad range of physiological and stress responses, neurovestibular changes indexed by ocular misalignment, and altered neurocognitive functioning, some of which match those of long-term spaceflight, but almost all of which did not differ from baseline (pre-flight) after return to Earth. Overall, these preliminary civilian spaceflight data suggest that short-duration missions do not pose a significant health risk, and moreover present a rich opportunity to measure the earliest phases of adaptation to spaceflight in the human body at anatomical, cellular, physiological and cognitive levels. Finally, these methods and results lay the foundation for an open, rapidly expanding biomedical database for astronauts, which can inform countermeasure development for both private and government-sponsored space missions.
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