作者:冯维维 来源:科学网微信公众号 发布时间:2023/10/7 20:23:15
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《自然》(20231005出版)一周论文导读

 

Nature, 5 October 2023, Volume 622 Issue 7981

《自然》2023年10月5日,第622卷,7981期

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物理学Physics

Outflows from the youngest stars are mostly molecular

最年轻恒星的流出物主要是分子

▲ 作者:T. P. Ray, M. J. McCaughrean, A. Caratti o Garatti, P. J. Kavanagh, K. Justtanont, E. F. van Dishoeck, M. Reitsma, H. Beuther, L. Francis, C. Gieser, P. Klaassen, G. Perotti, L. Tychoniec, M. van Gelder, L. Colina, Th. R. Greve, M. Güdel, Th. Henning, P. O. Lagage, G. stlin, B. Vandenbussche, C. Waelkens & G. Wright

▲ 链接:

https://www.nature.com/articles/s41586-023-06551-1

▲ 摘要:

恒星和行星的形成不仅伴随着物质的积累,即吸积,而且还伴随着物质以超音速射流的形式喷射,这种喷射可以延伸几个秒差距。由于吸积和喷流活动是相互关联的,而且年轻的恒星在早期迅速获得了大部分质量,所以最强大的喷流与最年轻的原恒星有关。然而,这一时期与原恒星及其周围环境被隐藏在许多星等在视觉上消失之后的时间相吻合。

毫米干涉仪可以探测这一阶段,但只能探测温度最低的部分。并未提供关于喷流中最热(大于1000 K)成分的信息,即原子、电离和高温分子气体,它们被认为构成了喷流的骨干。探测这样的骨干依赖于可穿透尘埃的红外线的观察。

研究者报告了詹姆斯·韦布太空望远镜对赫比格—哈罗211的近红外观测结果,这是一颗类似太阳的天体的流出物,当时其年龄最多只有104岁左右。这些观测结果揭示了热分子的大量辐射,解释了近20年前斯皮策太空望远镜发现的“绿色模糊”的起源。

与进化更多的同类相比,这种流出物的传播速度较慢,令人惊讶的是,几乎没有看到原子或电离发射的痕迹,这表明其主要成分几乎完全是分子的。

▲ Abstract:

The formation of stars and planets is accompanied not only by the build-up of matter, namely accretion, but also by its expulsion in the form of highly supersonic jets that can stretch for several parsecs. As accretion and jet activity are correlated and because young stars acquire most of their mass rapidly early on, the most powerful jets are associated with the youngest protostars. This period, however, coincides with the time when the protostar and its surroundings are hidden behind many magnitudes of visual extinction. Millimetre interferometers can probe this stage but only for the coolest components. No information is provided on the hottest (greater than 1,000 K) constituents of the jet, that is, the atomic, ionized and high-temperature molecular gases that are thought to make up the jet’s backbone. Detecting such a spine relies on observing in the infrared that can penetrate through the shroud of dust. Here we report near-infrared observations of Herbig-Haro 211 from the James Webb Space Telescope, an outflow from an analogue of our Sun when it was, at most, a few times 104 years old. These observations reveal copious emission from hot molecules, explaining the origin of the ‘green fuzzies discovered nearly two decades ago by the Spitzer Space Telescope. This outflow is found to be propagating slowly in comparison to its more evolved counterparts and, surprisingly, almost no trace of atomic or ionized emission is seen, suggesting its spine is almost purely molecular.

化学Chemistry

Hydrogen-bond-acceptor ligands enable distal C(sp3)–H arylation of free alcohols

氢键受体配体使游离醇的远端基化成为可能

▲ 作者:Daniel A. Strassfeld, Chia-Yu Chen, Han Seul Park, D. Quang Phan & Jin-Quan Yu

▲ 链接:

https://www.nature.com/articles/s41586-023-06485-8

▲ 摘要:

有机分子中碳氢键的功能化是化学合成最直接的方法之一。催化的最新进展使羧酸、酮和胺等天然化学基团能够控制和指导C(sp3) -H的活化。然而,作为有机化学中最常见的官能团之一的醇,由于其对晚期过渡金属催化剂的亲和力较低,仍然难以处理。研究者描述了使δ-C(sp3) -H键的醇定向芳基化的配体。

他们利用电荷平衡和二级配位球氢键相互作用——由结构—活性关系研究、计算模型和晶体学数据证明——来稳定l型羟基与钯的配位,从而促进关键C-H裂解过渡态的组装。在之前的C-H活化研究中,二级相互作用被用来控制已建立的反应活性背景下的选择性,与此相反,新研究证明了利用二级相互作用通过增强底物—催化剂亲和性来实现具有挑战性的、以前未知的反应活性的可行性。

▲ Abstract:

The functionalization of C–H bonds in organic molecules is one of the most direct approaches for chemical synthesis. Recent advances in catalysis have allowed native chemical groups such as carboxylic acids, ketones and amines to control and direct C(sp3)–H activation. However, alcohols, among the most common functionalities in organic chemistry, have remained intractable because of their low affinity for late transition-metal catalysts. Here we describe ligands that enable alcohol-directed arylation of δ-C(sp3)–H bonds. We use charge balance and a secondary-coordination-sphere hydrogen-bonding interaction—evidenced by structure–activity relationship studies, computational modelling and crystallographic data—to stabilize L-type hydroxyl coordination to palladium, thereby facilitating the assembly of the key C–H cleavage transition state. In contrast to previous studies in C–H activation, in which secondary interactions were used to control selectivity in the context of established reactivity, this report demonstrates the feasibility of using secondary interactions to enable challenging, previously unknown reactivity by enhancing substrate–catalyst affinity.

气候Climate

Global evidence of rapid urban growth in flood zones since 1985

1985年以来全球洪水地区城市快速增长的证据

▲ 作者:Jun Rentschler, Paolo Avner, Mattia Marconcini, Rui Su, Emanuele Strano, Michalis Vousdoukas & Stéphane Hallegatte

▲ 链接:

https://www.nature.com/articles/s41586-023-06468-9

▲ 摘要:

越来越多的证据表明,气候变化正在增加发生极端自然灾害的可能性。然而,将气候变化作为一种外生力量,使灾害超出地方和国家当局的影响范围,也被证明是权宜之计。当地决定的城市化和空间发展模式是人们遭受气候冲击和脆弱性的关键因素。

新研究利用高分辨率的年度数据表明,自1985年以来,世界各地的人类住区——从村庄到特大城市——不断迅速地扩展到今天的洪水区。

研究发现,在许多地区,最危险洪涝地区的增长速度远远超过非暴露区,特别是在东亚,高风险定居点的扩张速度比洪水安全定居点快60%。这些结果提供了系统的证据,证明各国面临洪水灾害的程度存在差异。许多国家不仅没有调整其风险敞口,反而继续积极扩大其对日益频繁的气候冲击的敞口。

▲ Abstract:

Disaster losses are increasing and evidence is mounting that climate change is driving up the probability of extreme natural shocks. Yet it has also proved politically expedient to invoke climate change as an exogenous force that supposedly places disasters beyond the influence of local and national authorities. However, locally determined patterns of urbanization and spatial development are key factors to the exposure and vulnerability of people to climatic shocks. Using high-resolution annual data, this study shows that, since 1985, human settlements around the world—from villages to megacities—have expanded continuously and rapidly into present-day flood zones. In many regions, growth in the most hazardous flood zones is outpacing growth in non-exposed zones by a large margin, particularly in East Asia, where high-hazard settlements have expanded 60% faster than flood-safe settlements. These results provide systematic evidence of a divergence in the exposure of countries to flood hazards. Instead of adapting their exposure, many countries continue to actively amplify their exposure to increasingly frequent climatic shocks.

Forced changes in the Pacific Walker circulation over the past millennium

过去一千年太平洋沃克环流的强迫变化

▲ 作者:Georgina Falster, Bronwen Konecky, Sloan Coats & Samantha Stevenson

▲ 链接:

https://www.nature.com/articles/s41586-023-06447-0

▲ 摘要:

太平洋沃克环流(PWC)对全球天气和气候有着巨大的影响。然而,它对外部强迫的反应尚不清楚,经验数据和模式模拟往往不同于这些反应的大小和迹象。大多数气候模型预测,PWC最终将因全球变暖而减弱。然而,PWC从1992年到2011年有所加强,这表明人为和/或火山气溶胶强迫或内部变率发挥了重要作用。

研究者使用了一个新的年度分解、多方法、古代理衍生的PWC重建集合(1200-2000)来表明1992-2011年PWC强化是异常的,但在过去800年的背景下并非史无前例。

研究者认为,1992-2011年PWC强化不太可能是火山强迫的结果,因此可能是人为气溶胶强迫或自然变率的结果。他们没有发现明显的工业时代(1850-2000)PWC趋势,与大多数气候模式模拟的PWC减弱形成对比。然而,工业时代向低频变率的转变表明存在微妙的人为影响。重建还表明,火山爆发引发类似厄尔尼诺的PWC减弱,与气候模型模拟的反应类似。

▲ Abstract:

The Pacific Walker circulation (PWC) has an outsized influence on weather and climate worldwide. Yet the PWC response to external forcings is unclear, with empirical data and mode simulations often disagreeing on the magnitude and sign of these responses. Most climate models predict that the PWC will ultimately weaken in response to global warming. However, the PWC strengthened from 1992 to 2011, suggesting a significant role for anthropogenic and/or volcanic aerosol forcing, or internal variability. Here we use a new annually resolved, multi-method, palaeoproxy-derived PWC reconstruction ensemble (1200–2000) to show that the 1992–2011 PWC strengthening is anomalous but not unprecedented in the context of the past 800 years. The 1992–2011 PWC strengthening was unlikely to have been a consequence of volcanic forcing and may therefore have resulted from anthropogenic aerosol forcing or natural variability. We find no significant industrial-era (1850–2000) PWC trend, contrasting the PWC weakening simulated by most climate models. However, an industrial-era shift to lower-frequency variability suggests a subtle anthropogenic influence. The reconstruction also suggests that volcanic eruptions trigger El Nio-like PWC weakening, similar to the response simulated by climate models.

生态Ecology

Protected areas slow declines unevenly across the tetrapod tree of life

保护区减缓四足动物数量的不均匀下降

▲ 作者:A. Justin Nowakowski, James I. Watling, Alexander Murray, Jessica L. Deichmann, Thomas S. Akre, Carlos L. Mu oz Brenes, Brian D. Todd, Louise McRae, Robin Freeman & Luke O. Frishkoff

▲ 链接:

https://www.nature.com/articles/s41586-023-06562-y

▲ 摘要:

保护区是减缓陆地生物多样性丧失的主要策略。尽管扩大保护区的覆盖范围是《生物多样性公约》的优先事项,但目前尚不清楚保护区是否缓解了整个四足动物生命树的下降,以及土地覆盖和气候变化在多大程度上改变了保护区的有效性。

研究者分析了全球2239种陆生脊椎动物种群的丰度变化率。平均而言,脊椎动物种群在保护区内的下降速度(- 0.4% /年)比在缺乏保护的类似地点(- 1.8% /年)慢5倍。研究发现,保护区的缓解效果在脊椎动物类别内部和不同类别中都有所不同,其中两栖动物和鸟类受益最大。

在土地覆被转换的地区,保护区对两栖动物的效益较低,在气候迅速变暖的地区,保护区对爬行动物的效益较低。相比之下,有效的国家治理不断增强了保护区的缓解影响。这项研究为保护区作为减缓四足动物衰退的策略的有效性提供了证据。

然而,优化不断增长的保护区网络需要有针对性地保护敏感分支,并减轻保护区边界之外的威胁。如果满足有针对性的保护、适当的治理和良好管理的景观条件,保护区可以在保护四足动物生物多样性方面发挥关键作用。

▲ Abstract:

Protected areas (PAs) are the primary strategy for slowing terrestrial biodiversity loss. Although expansion of PA coverage is prioritized under the Convention on Biological Diversity, it remains unknown whether PAs mitigate declines across the tetrapod tree of life and to what extent land cover and climate change modify PA effectiveness. Here we analysed rates of change in abundance of 2,239 terrestrial vertebrate populations across the globe. On average, vertebrate populations declined five times more slowly within PAs (0.4% per year) than at similar sites lacking protection (1.8% per year). The mitigating effects of PAs varied both within and across vertebrate classes, with amphibians and birds experiencing the greatest benefits. The benefits of PAs were lower for amphibians in areas with converted land cover and lower for reptiles in areas with rapid climate warming. By contrast, the mitigating impacts of PAs were consistently augmented by effective national governance. This study provides evidence for the effectiveness of PAs as a strategy for slowing tetrapod declines. However, optimizing the growing PA network requires targeted protection of sensitive clades and mitigation of threats beyond PA boundaries. Provided the conditions of targeted protection, adequate governance and well-managed landscapes are met, PAs can serve a critical role in safeguarding tetrapod biodiversity.

古人类学Paleo-anthropology

Evidence for the earliest structural use of wood at least 476,000 years ago

古人类约50万前或已开始使用木材

▲ 作者:L. Barham, G. A. T. Duller, I. Candy, C. Scott, C. R. Cartwright, J. R. Peterson, C. Kabukcu, M. S. Chapot, F. Melia, V. Rots, N. George, N. Taipale, P. Gethin & P. Nkombwe

▲ 链接:

https://www.nature.com/articles/s41586-023-06557-9

▲ 摘要:

早期石器时代的木制品很少能留存下来,它们需要特殊的保存条件,因此,关于古人类何时以及如何使用这种基本原料,所知有限。现在,研究者报告了考古记录中最早的木材结构使用证据。

赞比亚Kalambo瀑布考古遗址的水淹沉积物,通过发光可以追溯到至少47.6±2.3万年前,保存了两根互锁的原木,它们被一个故意切割的缺口横向连接在一起。这种建筑在非洲或欧亚旧石器时代没有已知的相似之处。

目前已知最早的木制人工制品是一块抛光的木板碎片,来自以色列Gesher Benot Ya’aqov的阿舍利遗址,距今已有780多年。用于觅食和狩猎的木制工具出现在400年前的欧洲、中国,还有非洲。

在Kalambo,研究者还发现了4件木制工具,包括楔子、挖掘棒、切割原木和缺口树枝。这些发现显示了一种意想不到的早期形态多样性,以及将树干塑造成大型组合结构的能力。这些新数据不仅扩大了非洲木工的年龄范围,而且扩大了人们对早期人类技术认知的理解。

▲ Abstract:

Wood artefacts rarely survive from the Early Stone Age since they require exceptional conditions for preservation; consequently, we have limited information about when and how hominins used this basic raw material1. We report here on the earliest evidence for structural use of wood in the archaeological record. Waterlogged deposits at the archaeological site of Kalambo Falls, Zambia, dated by luminescence to at least 476 ± 23 kyr ago (ka), preserved two interlocking logs joined transversely by an intentionally cut notch. This construction has no known parallels in the African or Eurasian Palaeolithic. The earliest known wood artefact is a fragment of polished plank from the Acheulean site of Gesher Benot Ya’aqov, Israel, more than 780 ka. Wooden tools for foraging and hunting appear 400 ka in Europe, China and possibly Africa. At Kalambo we also recovered four wood tools from 390 ka to 324 ka, including a wedge, digging stick, cut log and notched branch. The finds show an unexpected early diversity of forms and the capacity to shape tree trunks into large combined structures. These new data not only extend the age range of woodworking in Africa but expand our understanding of the technical cognition of early hominins, forcing re-examination of the use of trees in the history of technology.

 
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