编译｜李言
Nature, 27 June 2024, Volume 630 Issue 8018
《自然》, 2024年6月27日，第630卷，8018期
材料科学Materials Science
Large-area, self-healing block copolymer membranes for energy conversion
用于能量转换的大面积自愈嵌段共聚物膜
▲ 作者：Christian C. M. Sproncken, Peng Liu et.al
▲ 链接：
https://www.nature.com/articles/s41586-024-07481-2
▲ 摘要：
在此，我们介绍一种自组装策略，该策略使用水两相系统的界面来模板化和稳定扩展面积超过10 cm2且无缺陷的分子薄膜（约35 nm）仿生嵌段共聚物双层。
这些薄膜可自我修复，且对离子通过的屏障功能（比电阻约为1 MΩ cm2）接近磷脂膜。薄膜的流动性使分子载体能够进行直接的功能化，这些分子载体具有比钠离子更精细的选择性，可以将钾离子沿浓度梯度向下穿梭。这种离子选择性使得在模拟电射线的电器官的装置中，在NaCl和KCl的等摩尔溶液能够产生电能。
▲ Abstract：
Here we introduce a self-assembly strategy that uses the interface of an aqueous two-phase system to template and stabilize molecularly thin (approximately 35 nm) biomimetic block copolymer bilayers of scalable area that can exceed 10 cm2 without defects. These membranes are self-healing, and their barrier function against the passage of ions (specific resistance of approximately 1 MΩ cm2) approaches that of phospholipid membranes. The fluidity of these membranes enables straightforward functionalization with molecular carriers that shuttle potassium ions down a concentration gradient with exquisite selectivity over sodium ions. This ion selectivity enables the generation of electric power from equimolar solutions of NaCl and KCl in devices that mimic the electric organ of electric rays.
海洋科学Marine Science
Observations of diapycnal upwelling within a sloping submarine canyon
对倾斜海底峡中谷底旋上升流的观测
▲ 作者：Bethan L. Wynne-Cattanach, Nicole Couto et.al
▲ 链接：
https://www.nature.com/articles/s41586-024-07411-2
▲ 摘要：
在此，我们展示以每天100米的速率沿等高线上升的激烈近底部上升流，加上近边界和内部流体的绝热交换。这些观测是通过在倾斜海底峡谷内靠近海底释放一种染料进行的，它们为深海中以底部为中心的激烈底旋上升流提供了直接证据。这支持了先前的观点，即混合的地形特征（如峡谷）会在全球范围内导致显著的上升流。我们观测到的上升流速率大约比全球净上升流的平均值（约30 × 106 m3 s-1）高10000倍。
▲ Abstract：
Here we show vigorous near-bottom upwelling across isopycnals at a rate of the order of 100 metres per day, coupled with adiabatic exchange of near-boundary and interior fluid. These observations were made using a dye released close to the seafloor within a sloping submarine canyon, and they provide direct evidence of strong, bottom-focused diapycnal upwelling in the deep ocean. This supports previous suggestions that mixing at topographic features, such as canyons, leads to globally significant upwelling. The upwelling rates observed were approximately 10,000 times higher than the global average value required for approximately 30 × 106 m3 s-1 of net upwelling globally.
Rhizobia–diatom symbiosis fixes missing nitrogen in the ocean
根瘤菌—硅藻共生可固定海洋中缺失的氮
▲ 作者：Bernhard Tschitschko, Mertcan Esti et.al
▲ 链接：
https://www.nature.com/articles/s41586-024-07495-w
▲ 摘要：
在此，我们报告一种非蓝藻固氮共生体的发现——Candidatus Tectiglobus diatomicola，它为其硅藻宿主提供固定氮以换取光合碳。这种固氮共生体属于根瘤菌纲，它与单细胞硅藻的结合扩大了已知宿主的范围，超出了众所周知的陆地固氮根瘤菌与豆科的共生关系。
我们的研究结果表明，在北大西洋热带地区，根瘤菌—硅藻共生可以提供与蓝藻固氮一样多的固定氮，并且它们可能负责在蓝藻太稀少而无法解释测量率的广阔海洋地区固定氮。
▲ Abstract：
Here we report the discovery of a non-cyanobacterial N2-fixing symbiont, ‘Candidatus Tectiglobus diatomicola’, which provides its diatom host with fixed nitrogen in return for photosynthetic carbon. The N2-fixing symbiont belongs to the order Rhizobiales and its association with a unicellular diatom expands the known hosts for this order beyond the well-known N2-fixing rhizobia–legume symbioses on land. Our results show that the rhizobia–diatom symbioses can contribute as much fixed nitrogen as can cyanobacterial N2 fixers in the tropical North Atlantic, and that they might be responsible for N2 fixation in the vast regions of the ocean in which cyanobacteria are too rare to account for the measured rates.
医学Medicine
Sleep loss diminishes hippocampal reactivation and replay
睡眠不足会减少海马体的再激活和重放能力
▲ 作者：Bapun Giri, Nathaniel Kinsky, Utku Kaya, Kourosh Maboudi, Ted Abel & Kamran Diba
▲ 链接：
https://www.nature.com/articles/s41586-024-07538-2
▲ 摘要：
在这里，我们记录了大鼠在经历迷宫探索、睡眠和睡眠剥夺后进行恢复性睡眠， 12小时的CA1神经元活动。我们发现，在睡眠剥夺期间，海马尖波涟漪（SWRs）表现出持续或更高的频率，但功率较低，频率波动较高。锥体细胞在睡眠剥夺时表现出持续的放电，而在睡眠状态时则表现出放电减少，但无论睡眠状态如何，它们在SWRs期间的放电率都是相似的。尽管在睡眠剥夺期间有强大的放电和丰富的SWRs，但我们发现在这些时期神经元放电模式的再激活和重放减少了，与自由睡眠相比，在某些情况下甚至完全消失了。在恢复性睡眠后，大脑的再激活会部分反弹，但没有达到自然睡眠时的水平。
▲ Abstract：
Here we recorded CA1 neuronal activity over 12 h in rats across maze exploration, sleep and sleep deprivation, followed by recovery sleep. We found that sharp-wave ripples (SWRs) showed sustained or higher rates during sleep deprivation but with lower power and higher frequency ripples. Pyramidal cells exhibited sustained firing during sleep deprivation and reduced firing during sleep, yet their firing rates were comparable during SWRs regardless of sleep state. Despite the robust firing and abundance of SWRs during sleep deprivation, we found that the reactivation and replay of neuronal firing patterns was diminished during these periods and, in some cases, completely abolished compared to ad libitum sleep. Reactivation partially rebounded after recovery sleep but failed to reach the levels found in natural sleep.
考古学Archaeology
Ancient genomes reveal insights into ritual life at Chichén Itzá
古代基因组揭示奇琴伊察的祭祀生活
▲ 作者：Rodrigo Barquera, Oana Del Castillo-Chávez et.al
▲ 链接：
https://www.nature.com/articles/s41586-024-07509-7
▲ 摘要：
在此，我们展示了从64个可追溯到公元500—900年左右的亚成年个体中获得的全基因组数据，这些个体是奇琴伊察祭祀中心的神圣天坑附近的一个地下群葬中发现的。遗传分析表明，所分析的个体均为男性，有几个个体亲缘关系密切，包括两对同卵双胞胎。
双胞胎因体现了神和英雄之间的二元性，在玛雅和更广泛的中美洲神话中占有突出地位，但直到现在，他们还没有在古代玛雅人的殡葬中被识别出来。除了与人类免疫有关的某些遗传位点（包括人类白细胞抗原复合物）外，该地区现代人的基因对比显示出与奇琴伊察古代居民的遗传具有连续性，这可能是殖民时期传入该地区的传染病而导致的适应的信号。
▲ Abstract：
Here we present genome-wide data obtained from 64 subadult individuals dating to around AD 500–900 that were found in a subterranean mass burial near the Sacred Cenote (sinkhole) in the ceremonial centre of Chichén Itzá. Genetic analyses showed that all analysed individuals were male and several individuals were closely related, including two pairs of monozygotic twins. Twins feature prominently in Mayan and broader Mesoamerican mythology, where they embody qualities of duality among deities and heroes, but until now they had not been identified in ancient Mayan mortuary contexts. Genetic comparison to present-day people in the region shows genetic continuity with the ancient inhabitants of Chichén Itzá, except at certain genetic loci related to human immunity, including the human leukocyte antigen complex, suggesting signals of adaptation due to infectious diseases introduced to the region during the colonial period.
管理学Management Science
Hybrid working from home improves retention without damaging performance
混合办公可以在不影响工作表现的情况下提高员工留存率
▲ 作者：Nicholas Bloom, Ruobing Han & James Liang
▲ 链接：
https://www.nature.com/articles/s41586-024-07500-2
▲ 摘要：
在此，我们进行了一项为期六个月的随机对照试验，调查了2021—2022年间一家中国科技公司1612名员工在家混合办公的情况。我们发现，混合工作提高了工作满意度，并将辞职率降低了三分之一。对于非管理人员、女性员工和通勤时间较长的人来说，辞职率的下降非常显著。零等效性测试表明，在今后两年的审查中，混合工作不影响绩效成绩。我们没有发现任何证据表明，在接下来的两年里，无论是总体还是在任何主要的员工群体中，晋升方面会存在差异。
最后，零等效性测试也表明，混合办公对计算机工程师员工编写代码没有影响。我们还发现，在实验中，395位管理者改变了他们对混合办公对生产力影响的看法，从实验前的负面影响（平均为- 2.6%）到实验后感知到的积极影响（+1.0%）。这些结果表明，每周在家工作两天的混合办公计划不会降低员工的表现。
▲ Abstract：
Here we ran a six-month randomized control trial investigating the effects of hybrid working from home on 1,612 employees in a Chinese technology company in 2021–2022. We found that hybrid working improved job satisfaction and reduced quit rates by one-third. The reduction in quit rates was significant for non-managers, female employees and those with long commutes. Null equivalence tests showed that hybrid working did not affect performance grades over the next two years of reviews. We found no evidence for a difference in promotions over the next two years overall, or for any major employee subgroup. Finally, null equivalence tests showed that hybrid working had no effect on the lines of code written by computer-engineer employees. We also found that the 395 managers in the experiment revised their surveyed views about the effect of hybrid working on productivity, from a perceived negative effect (2.6% on average) before the experiment to a perceived positive one (+1.0%) after the experiment. These results indicate that a hybrid schedule with two days a week working from home does not damage performance.
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