《自然》（20230713出版）一周論文導讀

原文地址：http://news.sciencenet.cn/htmlnews/2023/7/504791.shtm

編譯 | 馮維維

Nature, 13 July 2023, Volume 619 Issue 7969

《自然》2023年7月13日，第619卷，7969期

物理學Physics

XGalaxies in voids assemble their stars slowly

空洞星系緩慢地聚合其恒星

▲ 作者：Jesús Domínguez-Gómez, Isabel Pérez, Tomás Ruiz-Lara, Reynier F. Peletier, Patricia Sánchez-Blázquez, Ute Lisenfeld, Jesús Falcón-Barroso, Manuel Alcázar-Laynez, María Argudo-Fernández, Guillermo Blázquez-Calero, Hélène Courtois, Salvador Duarte Puertas, Daniel Espada, Estrella Florido, Rubén García-Benito, Andoni Jiménez, Kathryn Kreckel, Mónica Relao, Laura Sánchez-Menguiano, Thijs van der Hulst, Rien van de Weygaert, Simon Verley & Almudena Zurita

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06109-1

▲ 摘要：

宇宙中的星系以網狀結構分布，誕生于不同的大尺度環境：密集的星系團、細長的細絲、片狀的壁和稱為空洞的低密度區域。科學家推測空洞中的低密度會影響其星系的性質。

事實上，此前的研究表明，空洞中的星系平均顏色更藍、質量更小，且比密度更大的大尺度環境中的星系具有更晚的形態和更高的當前恒星形成率。然而，在觀測上尚未證明過空洞中的恒星形成歷史（SFH）與細絲、壁和星團中的恒星形成歷史有何本質上的不同。

研究者展示了空洞星系比密度更大的大尺度環境中的星系平均有更慢的SFH。他們還發現兩種主要的SFH類型存在于所有環境中：“短時間尺度”星系在早期不受其大尺度環境的影響，而只在其生命后期；“長時間尺度”星系不斷受到其環境和恒星質量的影響。這兩種類型在空隙中都比在絲、壁和星系團中進化得慢。

▲ Abstract：

 Galaxies in the Universe are distributed in a web-like structure characterized by different large-scale environments: dense clusters, elongated filaments, sheetlike walls and under-dense regions, called voids. The low density in voids is expected to affect the properties of their galaxies. Indeed, previous studies have shown that galaxies in voids are, on average, bluer and less massive, and have later morphologies and higher current star formation rates than galaxies in denser large-scale environments. However, it has never been observationally proved that the star formation histories (SFHs) in voids are substantially different from those in filaments, walls and clusters. Here we show that void galaxies have had, on average, slower SFHs than galaxies in denser large-scale environments. We also find two main SFH types present in all the environments: ‘short-timescale’ galaxies are not affected by their large-scale environment at early times but only later in their lives; ‘long-timescale’ galaxies have been continuously affected by their environment and stellar mass. Both types have evolved more slowly in voids than in filaments, walls and clusters.

Resolved imaging confirms a radiation belt around an ultracool dwarf

高分辨率成像證實一顆超冷矮星周圍存在輻射帶

▲ 作者：Melodie M. Kao, Amy J. Mioduszewski, Jackie Villadsen & Evgenya L. Shkolnik

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06138-w

▲ 摘要：

高輻射帶存在于所有大尺度的太陽系行星磁層：地球、木星、土星、天王星和海王星。這些持續存在的赤道地帶的相對論粒子能量高達數十兆電子伏特，可延伸至行星半徑的十倍以上，發射出逐漸變化的無線電輻射，并影響近地衛星的表面化學。

最近的觀測表明，統稱為超冷矮星的極低質量的恒星和褐矮星，可以產生類似行星的無線電發射，如大規模磁層電流周期性爆發的極光。它們也表現出緩慢變化的靜態無線電發射，據了解可追蹤低水平的日冕耀斑，盡管偏離了以經驗為依據的多波長耀斑關系。

研究者展示了超低溫矮星LSR J1835 + 3259在8.4 GHz的高分辨率成像，表明它的靜態無線電發射是空間分辨的，并追蹤到雙葉和軸對稱結構，在形態上與木星輻射帶相似。這兩個葉瓣之間的距離高達18個超冷矮星半徑，研究者在一年多的時間里進行了三次觀測，發現其穩定存在。

對于受LSR J1835 + 3259磁偶極子約束的等離子體，研究者估計其電子能量為15 MeV，與木星的輻射帶一致。該結果證實了最近對恒星質量序列兩端輻射帶的預測，并支持更廣泛地重新研究旋轉磁偶極子在棕矮星、完全對流的M矮星和大質量恒星產生非熱靜態射電輻射的過程。

▲ Abstract：

Radiation belts are present in all large-scale Solar System planetary magnetospheres: Earth, Jupiter, Saturn, Uranus and Neptune. These persistent equatorial zones of relativistic particles up to tens of megaelectron volts in energy can extend further than ten times the planet’s radius, emit gradually varying radio emissions and affect the surface chemistry of close-in moons. Recent observations demonstrate that very low-mass stars and brown dwarfs, collectively known as ultracool dwarfs, can produce planet-like radio emissions such as periodically bursting aurorae from large-scale magnetospheric currents. They also exhibit slowly varying quiescent radio emissions hypothesized to trace low-level coronal flaring despite departing from empirical multiwavelength flare relationships. Here we present high-resolution imaging of the ultracool dwarf LSR J1835+3259 at 8.4GHz, demonstrating that its quiescent radio emission is spatially resolved and traces a double-lobed and axisymmetrical structure that is similar in morphology to the Jovian radiation belts. Up to 18 ultracool dwarf radii separate the two lobes, which are stably present in three observations spanning more than one year. For plasma confined by the magnetic dipole of LSR J1835+3259, we estimate 15MeV electron energies, consistent with Jupiter’s radiation belts. Our results confirm recent predictions of radiation belts at both ends of the stellar mass sequence and support broader re-examination of rotating magnetic dipoles in producing non-thermal quiescent radio emissions from brown dwarfs7, fully convective M dwarfs20 and massive stars.

化學Chemistry

Organic–inorganic covalent–ionic molecules for elastic ceramic plastic

彈性陶瓷塑料用有機-無機共價離子分子

▲ 作者：Weifeng Fang, Zhao Mu, Yan He, Kangren Kong, Kai Jiang, Ruikang Tang & Zhaoming Liu

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06117-1

▲ 摘要：

盡管有機-無機雜化材料在機械、光學、電子和生物醫學等領域發揮著不可替代的作用，但由于有機共價鍵和無機離子鍵在分子結構上的不同行為，分離的有機-無機雜化分子（目前僅限于共價化合物）很少被用于制備雜化材料。研究者將典型的共價鍵和離子鍵整合在一個分子內，形成有機-無機雜化分子，可用于自底向上合成雜化材料。

有機共價硫辛酸（TA）與無機離子型碳酸鈣低聚物（CCO）通過酸堿反應結合，得到具有代表性的分子式TA2Ca(CaCO3)2的TA - CCO雜化分子。其雙重反應性涉及有機TA段和無機CCO段的共聚，產生各自的共價和離子網絡。

這兩個網絡通過TA-CCO絡合物相互連接，在得到的雜化材料中形成共價離子雙連續結構，從而統一了矛盾的機械性能。有機-無機雜化分子的自下而上構建為雜化材料的分子工程提供了一條可行的途徑，補充了經典的有機-無機雜化材料制造方法。

▲ Abstract：

Although organic–inorganic hybrid materials have played indispensable roles as mechanical, optical, electronic and biomedical materials, isolated organic–inorganic hybrid molecules (at present limited to covalent compounds) are seldom used to prepare hybrid materials, owing to the distinct behaviours of organic covalent bonds and inorganic ionic bonds in molecular construction. Here we integrate typical covalent and ionic bonds within one molecule to create an organic–inorganic hybrid molecule, which can be used for bottom-up syntheses of hybrid materials. A combination of the organic covalent thioctic acid (TA) and the inorganic ionic calcium carbonate oligomer (CCO) through an acid–base reaction provides a TA–CCO hybrid molecule with the representative molecular formula TA2Ca(CaCO3)2. Its dual reactivity involving copolymerization of the organic TA segment and inorganic CCO segment generates the respective covalent and ionic networks. The two networks are interconnected through TA–CCO complexes to form a covalent–ionic bicontinuous structure within the resulting hybrid material, poly(TA–CCO), which unifies paradoxical mechanical properties. The bottom-up creation of organic–inorganic hybrid molecules provides a feasible pathway for the molecular engineering of hybrid materials, thereby supplementing the classical methodology used for the manufacture of organic–inorganic hybrid materials.

Linear-in-temperature resistivity for optimally superconducting (Nd,Sr)NiO2

具鎳酸鹽讓超導體無序程度降低

▲ 作者：IKyuho Lee, Bai Yang Wang, Motoki Osada, Berit H. Goodge, Tiffany C. Wang, Yonghun Lee, Shannon Harvey, Woo Jin Kim, Yijun Yu, Chaitanya Murthy, Srinivas Raghu, Lena F. Kourkoutis & Harold Y. Hwang

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06129-x

▲ 摘要：

在物質的各種強相關相附近發生的超導性引起了對其正常狀態性質的廣泛關注，以了解超導性產生的狀態。最近在層狀鎳酸鹽中發現的超導性引起了類似的興趣。但由于這些亞穩化合物的材料限制，摻雜無限層鎳酸鹽薄膜的輸運測量受到阻礙：特別是高密度的擴展缺陷。

研究者通過移動到生長和還原條件更穩定的底物（LaAlO3）0.3（Sr2TaAlO6）0.7，可以合成基本沒有擴展缺陷的Nd1-xSrxNiO2摻雜系列。

在不摻雜的情況下，正常狀態電阻率在欠摻雜狀態下表現為低溫上升，在最佳摻雜狀態下表現為線性行為，在過摻雜狀態下表現為二次溫度依賴關系。這在現象上與銅氧化物相似，盡管有關鍵的區別——即沒有絕緣母化合物、多帶電子結構和莫特-哈伯德軌道排列，而不是銅氧化物的電荷轉移絕緣體。

無論是在轉變溫度和摻雜范圍方面，研究者進一步觀察到超導性的增強。這些結果表明，隨著鎳酸鹽無序程度的降低，兩個超導族的電子性質趨于一致。

▲ Abstract：

The occurrence of superconductivity in proximity to various strongly correlated phases of matter has drawn extensive focus on their normal state properties, to develop an understanding of the state from which superconductivity emerges. The recent finding of superconductivity in layered nickelates raises similar interests. However, transport measurements of doped infinite-layer nickelate thin films have been hampered by materials limitations of these metastable compounds: in particular, a high density of extended defects. Here, by moving to a substrate（LaAlO3）0.3（Sr2TaAlO6）0.7 that better stabilizes the growth and reduction conditions, we can synthesize the doping series of Nd1-xSrxNiO2 essentially free from extended defects. In their absence, the normal state resistivity shows a low-temperature upturn in the underdoped regime, linear behaviour near optimal doping and quadratic temperature dependence for overdoping. This is phenomenologically similar to the copper oxides despite key distinctions—namely, the absence of an insulating parent compound, multiband electronic structure and a Mott–Hubbard orbital alignment rather than the charge-transfer insulator of the copper oxides. We further observe an enhancement of superconductivity, both in terms of transition temperature and range of doping. These results indicate a convergence in the electronic properties of both superconducting families as the scale of disorder in the nickelates is reduced.  

生態和氣候Ecology & Climate

Plastic debris in lakes and reservoirs

湖泊和水庫中的塑料碎片

▲ 作者：Veronica Nava, Sudeep Chandra, Julian Aherne, María B. Alfonso, Ana M. Anto-Geraldes, Katrin Attermeyer, Roberto Bao, Mireia Bartrons, Stella A. Berger, Marcin Biernaczyk, Raphael Bissen, Justin D. Brookes, David Brown, Miguel Caedo-Argüelles, Moisés Canle, Camilla Capelli, Rafael Carballeira, José Luis Cereijo, Sakonvan Chawchai, Sren T. Christensen, Kirsten S. Christoffersen, Elvira de Eyto, Jorge Delgado, Tyler N. Dornan, …Barbara Leoni Show authors

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06168-4

▲ 摘要：

塑料垃圾被認為在全球淡水生態系統中普遍存在。然而，由于缺乏全面和可比較的數據，對其分布進行嚴格評估具有挑戰性。研究者提出了一項標準化的跨國調查，評估淡水生態系統中塑料碎片的豐度和類型。

他們對38個湖泊和水庫的地表水進行了采樣，分布在地理位置和湖泊屬性的梯度上，目的是確定與塑料觀察增加相關的因素，結果在所有被研究的湖泊和水庫中都發現了塑料碎片，這表明這些生態系統在塑料污染循環中起著關鍵作用。

研究結果表明，兩種類型的湖泊特別容易受到塑料污染：一種是人口稠密和城市化地區的湖泊和水庫；另一種是沉積面積高、蓄水時間長、人為影響程度高的大型湖泊和水庫。不同湖泊的塑料濃度差異很大；在污染最嚴重的地區，濃度達到甚至超過了報告的亞熱帶海洋環流，海洋區域收集了大量的碎片。該研究結果強調了在污染管理和持續提供湖泊生態系統服務的背景下，在解決塑料污染時包括湖泊和水庫的重要性。

▲ Abstract：

Plastic debris is thought to be widespread in freshwater ecosystems globally. However, a lack of comprehensive and comparable data makes rigorous assessment of its distribution challenging. Here we present a standardized cross-national survey that assesses the abundance and type of plastic debris (>250 μm) in freshwater ecosystems. We sample surface waters of 38 lakes and reservoirs, distributed across gradients of geographical position and limnological attributes, with the aim to identify factors associated with an increased observation of plastics. We find plastic debris in all studied lakes and reservoirs, suggesting that these ecosystems play a key role in the plastic-pollution cycle. Our results indicate that two types of lakes are particularly vulnerable to plastic contamination: lakes and reservoirs in densely populated and urbanized areas and large lakes and reservoirs with elevated deposition areas, long water-retention times and high levels of anthropogenic influence. Plastic concentrations vary widely among lakes; in the most polluted, concentrations reach or even exceed those reported in the subtropical oceanic gyres, marine areas collecting large amounts of debris. Our findings highlight the importance of including lakes and reservoirs when addressing plastic pollution, in the context of pollution management and for the continued provision of lake ecosystem services.

A warming-induced reduction in snow fraction amplifies rainfall extremes

由變暖引起的雪量減少放大了極端降雨

▲ 作者：Mohammed Ombadi, Mark D. Risser, Alan M. Rhoades & Charuleka Varadharajan 

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06092-7

▲ 摘要：

在氣候變暖的情況下，極端降水事件的強度預計會增加，這對自然和人工環境中的水可持續性構成了巨大挑戰。特別重要的是極端降雨，它們會瞬間引發徑流并與洪水、滑坡和土壤侵蝕有關。然而，迄今為止，關于降水極值強化的大量文獻尚未單獨考察降水相的極值，即液體降水和固體降水。

研究表明北半球高海拔地區極端降雨的增加被放大了，平均每升溫1攝氏度就會增加15%——是大氣中水蒸氣增加的預期速率的兩倍。研究者利用氣候再分析數據集和未來模式預估表明，這種增加是由于變暖引起的從雪到雨的轉變導致的。

此外，研究還證明了極端降水預估的模式間不確定性可以通過雪雨分配的變化（決定系數0.47）得到很好的解釋。研究結果表明，高海拔地區是未來容易受到極端降雨相關災害風險影響的“熱點”，因此需要強有力的氣候適應計劃來減輕潛在風險。此外，研究結果為減少極端降雨預測中的模式不確定性提供了一條途徑。

▲ Abstract：