作者:李言 来源:科学网微信公众号 发布时间:2024/1/13 20:38:44
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《自然》(20240111出版)一周论文导读

 

Nature, 11 January 2024, Volume 625 Issue 7994

《自然》2024年1月11日,第625卷,7994期

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天文学Astronomy

A 12.4-day periodicity in a close binary system after a supernova

在超新星之后周期为12.4天的密近双星系统

▲ 作者:Ping Chen, Avishay Gal-Yam, Jesper Sollerman et al.

▲ 链接:

https://www.nature.com/articles/s41586-023-06787-x

▲ 摘要:

在此,我们报告了一颗在衰减光曲线中显示出12.4天的周期波动的超新星SN 2022jli。具有一致周期速度位移的窄Hα发射谱线在晚时间光谱中被检测到,这可能是由于伴星剥离的氢气被吸积到致密的残骸上。一个新的费米LAT γ射线源在时间和位置上与SN 2022jli一致。

我们观测到的SN 2022jli的特性,包括光学光曲线的周期性波动、相干Hα发射位移以及与γ射线源相关的证据,指向因双星系统中一颗大质量恒星的爆炸留下的遗迹。伴星对致密天体的质量吸积为超新星的光曲线提供了动力,并产生了γ射线发射。

▲ Abstract:

Here we report a stripped-envelope supernova, SN 2022jli, which shows 12.4-day periodic undulations during the declining light curve. Narrow Hα emission is detected in late-time spectra with concordant periodic velocity shifts, probably arising from hydrogen gas stripped from a companion and accreted onto the compact remnant. A new Fermi-LAT γ-ray source is temporally and positionally consistent with SN 2022jli. The observed properties of SN 2022jli, including periodic undulations in the optical light curve, coherent Hα emission shifting and evidence for association with a γ-ray source, point to the explosion of a massive star in a binary system leaving behind a bound compact remnant. Mass accretion from the companion star onto the compact object powers the light curve of the supernova and generates the γ-ray emission.

物理学Physics

Encoding a magic state with beyond break-even fidelity

以超过收支平衡的保真度编码一个魔法态

▲ 作者:Riddhi S. Gupta, Neereja Sundaresan et al.

▲ 链接:

https://www.nature.com/articles/s41586-023-06846-3

▲ 摘要:

在此,我们提出并实现了一种利用纠错技术在超导量子比特阵列上制备魔法态的方案。我们的方案比那些可以使用设备的单个量子比特制备的魔法态更好。这证明了容错量子计算的基本原理,即我们可以使用纠错来提高带有噪声量子比特的逻辑门的质量。

此外,我们还表明,使用自适应电路可以增加魔法态的产量,其中电路元件根据中路测量的结果而改变。这展示了许多纠错子例程所需的基本功能。

▲ Abstract:

Here we propose and implement a scheme to prepare a magic state on a superconducting qubit array using error correction. We find that our scheme produces better magic states than those that can be prepared using the individual qubits of the device. This demonstrates a fundamental principle of fault-tolerant quantum computing, namely, that we can use error correction to improve the quality of logic gates with noisy qubits. Moreover, we show that the yield of magic states can be increased using adaptive circuits, in which the circuit elements are changed depending on the outcome of mid-circuit measurements. This demonstrates an essential capability needed for many error-correction subroutines.

材料科学Materials Science

Three-dimensional integration of two-dimensional field-effect transistors

二维场效应晶体管的三维集成

▲ 作者:Darsith Jayachandran, Rahul Pendurthi et al.

▲ 链接:

https://www.nature.com/articles/s41586-023-06860-5

▲ 摘要:

在这里,我们展示了:(1)基于MoS2的晶圆级单片两层3D集成,每层有超过10000个场效应晶体管(FET);(2)基于MoS2和WSe2的三层3D集成,每层约500个FET;(3)基于每层200个缩放MoS2 FET(通道长度,LCH = 45 nm)的两层3D集成。

我们还实现了一个3D电路,并演示了多功能,包括传感和存储。我们的演示将成为更复杂、高密度和功能多样化的集成电路的基础,这些集成电路在第三维度上具有更多的单片集成层。

▲ Abstract:

Here we demonstrate (1) wafer-scale and monolithic two-tier 3D integration based on MoS2 with more than 10,000 field-effect transistors (FETs) in each tier; (2) three-tier 3D integration based on both MoS2 and WSe2 with about 500 FETs in each tier; and (3) two-tier 3D integration based on 200 scaled MoS2 FETs (channel length, LCH?=?45?nm) in each tier. We also realize a 3D circuit and demonstrate multifunctional capabilities, including sensing and storage. We believe that our demonstrations will serve as the foundation for more sophisticated, highly dense and functionally divergent integrated circuits with a larger number of tiers integrated monolithically in the third dimension.

化学Chemistry

Catalytic asymmetric cationic shifts of aliphatic hydrocarbons

脂肪烃催化不对称阳离子转移

▲ 作者:Vijay N. Wakchaure, William DeSnoo et al.

▲ 链接:

https://www.nature.com/articles/s41586-023-06826-7

▲ 摘要:

不对称催化是化学合成的一个先进领域,但处理丰富的纯脂肪烃依然具有挑战性。在此,我们描述了咪胺二磷酰亚胺催化的脂肪族烯基环烷烃不对称瓦格纳-梅尔外因转变为具有优异的区域和对映选择性的环烯烃。

尽管瓦格纳-梅尔外因反应历史悠久,与化学合成和生物合成密切相关,但如瓦格纳和梅尔外因最初描述的那样,瓦格纳-梅尔外因反应利用纯脂肪烃曾避免不对称催化。

▲ Abstract:

Asymmetric catalysis is an advanced area of chemical synthesis, but the handling of abundantly available, purely aliphatic hydrocarbons has proven to be challenging. We describe here an imidodiphosphorimidate-catalysed asymmetric Wagner–Meerwein shift of aliphatic alkenyl cycloalkanes to cycloalkenes with excellent regio- and enantioselectivity. Despite their long history and high relevance for chemical synthesis and biosynthesis, Wagner–Meerwein reactions utilizing purely aliphatic hydrocarbons, such as those originally reported by Wagner and Meerwein, had previously eluded asymmetric catalysis.

气候科学Climate Science

Evidence of human influence on Northern Hemisphere snow loss

人类对北半球雪损失影响的证据

▲ 作者:Alexander R. Gottlieb & Justin S. Mankin

▲ 链接:

https://www.nature.com/articles/s41586-023-06794-y

▲ 摘要:

在此,我们展示了1981—2020年期间,人为引起的变暖导致了北半球3月份积雪量的下降。利用积雪重建的集合,我们确定了北半球169个主要河流流域中的82个强劲降雪趋势,其中31个我们归因于人类的影响。

最重要的是,我们展示了积雪的可推广和高度非线性的温度敏感性,其中当冬季气候温度超过零下8摄氏度时,积雪对温度上升1摄氏度变得更敏感。这种非线性解释了迄今为止没有广泛的积雪损失,并预示着人口最多的流域的下降幅度和水安全风险会更大。

综上所述,我们的研究结果强调,人为造成的雪损失及其对水资源的影响是可归因的——即使在个别情况中没有明确的检测——并且将随着近期变暖而加速和均匀化,在没有实质性气候缓解的情况下会对水资源造成风险。

▲ Abstract:

Here we show that human-caused warming has caused declines in Northern Hemisphere-scale March snowpack over the 1981–2020 period. Using an ensemble of snowpack reconstructions, we identify robust snow trends in 82 out of 169 major Northern Hemisphere river basins, 31 of which we can confidently attribute to human influence. Most crucially, we show a generalizable and highly nonlinear temperature sensitivity of snowpack, in which snow becomes marginally more sensitive to one degree Celsius of warming as climatological winter temperatures exceed minus eight degrees Celsius. Such nonlinearity explains the lack of widespread snow loss so far and augurs much sharper declines and water security risks in the most populous basins. Together, our results emphasize that human-forced snow losses and their water consequences are attributable—even absent their clear detection in individual snow products—and will accelerate and homogenize with near-term warming, posing risks to water resources in the absence of substantial climate mitigation.

生物学Bbiology

Emergence of replication timing during early mammalian development

哺乳动物早期发育过程中复制时间的出现

▲ 作者:Tsunetoshi Nakatani, Tamas Schauer et al.

▲ 链接:

https://www.nature.com/articles/s41586-023-06872-1

▲ 摘要:

在此,我们使用单细胞Repli—seq生成了小鼠胚胎从受精卵到囊胚阶段的全基因组RT图谱。我们的数据显示,RT最初不明确,但从4细胞期开始逐渐明确,与A和B区室的强化相一致。

我们发现转录有助于提高RT程序的准确性,并且A和B区室之间RT的差异取决于合子基因组激活时的RNA聚合酶II。我们的数据表明,核组织的建立先于定义的RT特征的获得,并启动基因组划分为早期和晚期复制结构域。

我们的研究揭示了哺乳动物发育初期表观基因组的建立,揭示了基因组组织的组织原则。

▲ Abstract:

Here, using single-cell Repli-seq, we generated genome-wide RT maps of mouse embryos from the zygote to the blastocyst stage. Our data show that RT is initially not well defined but becomes defined progressively from the 4-cell stage, coinciding with strengthening of the A and B compartments. We show that transcription contributes to the precision of the RT programme and that the difference in RT between the A and B compartments depends on RNA polymerase?II at zygotic genome activation. Our data indicate that the establishment of nuclear organization precedes the acquisition of defined RT features and primes the partitioning of the genome into early- and late-replicating domains. Our work sheds light on the establishment of the epigenome at the beginning of mammalian development and reveals the organizing principles of genome organization.

 
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