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Science, 1 MAR 2024, VOL 383, ISSUE 6686

《明升体育app》2024年3月1日，第383卷，6686期

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天文学Astronomy

A far-ultraviolet–driven photoevaporation flow observed in a protoplanetary disk

在原行星盘中观察到远紫外线驱动的光致蒸发流

▲ 作者：OLIVIER BERNé, EMILIE HABART et al.

▲ 链接：

▲ 摘要：

大多数低质量恒星都是在包含大质量恒星的星团中形成的，这些恒星是远紫外线（FUV）辐射的来源。理论模型预测，这种FUV辐射会在低质量恒星周围的原行星盘表面产生光解离区（PDRs），从而影响盘内行星的形成。

我们手机版韦布太空望远镜和阿塔卡马大型毫米波阵列在猎户座星云中观测到一个FUV辐射原行星盘。从PDR中检测到了发射线；对它们的动力学和激发进行建模使我们能够限制气体中的物理情况。

我们量化了FUV辐射引起的质量损失率，发现它足以在不到一百万年的时间内从星盘中剥离气体。这个速度足以影响盘内巨行星的形成。

▲ Abstract：

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.

生物学Biology

Defective pollen tube tip growth induces neo-polyploid infertility

花粉管尖端生长缺陷导致新多倍体不育

▲ 作者：JENS WESTERMANN, THANVI SRIKANT et al.

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▲ 摘要：

在此，我们手机版了拟南芥新多倍体花粉管尖端生长的严重育性缺陷。新形成的多倍体拟南芥A. arenosa花粉管生长缓慢，具有解剖和生理异常的情况，且经常过早破裂，导致基因表达改变。

这些表型会在进化的多倍体中恢复。我们还发现，在自然四倍体A. arenosa中，有两个尖端生长基因的配子体（花粉管）基因型与四倍体的花粉管性能密切相关。我们的工作确定了花粉管尖端生长是新多倍体植物的重要生育挑战，并为自然进化的多基因解决方案提供了见解。

▲ Abstract：

Here we report that a severe fertility-compromising defect in pollen tube tip growth arises in new polyploids of Arabidopsis arenosa. Pollen tubes of newly polyploid A. arenosa grow slowly, have aberrant anatomy and disrupted physiology, often burst prematurely, and have altered gene expression. These phenotypes recover in evolved polyploids. We also show that gametophytic (pollen tube) genotypes of two tip-growth genes under selection in natural tetraploid A. arenosa are strongly associated with pollen tube performance in the tetraploid. Our work establishes pollen tube tip growth as an important fertility challenge for neo-polyploid plants and provides insights into a naturally evolved multigenic solution.

Divergent responses of pelagic and benthic fish body-size structure to remoteness and protection from humans

远洋和底栖鱼类体型结构在远离人类和人类保护情况下的不同反应

▲ 作者：TOM B. LETESSIER, DAVID MOUILLOT et al.

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▲ 摘要：

在这项研究中，我们从17411个立体诱饵视频部署中得出鱼类体积指示，以测试远洋和底栖生物对远离人类压力的反应差异以及海洋保护区（MPAs）的有效性。

通过研究823849条鱼的记录，我们手机版了不同系统之间的不同反应，远洋鱼类的梯级结构相比底栖鱼类的体积结构在人类活动区域附近受到更严重的侵蚀，这表明上层海洋系统更容易受到人类压力的影响。

通过设立海洋保护区，可以有效地保护底栖鱼类的体积结构，从而有助于底栖鱼类栖息地和相关鱼类的恢复。相比之下，要恢复世界上最大和最濒危的远洋鱼类，就需要在偏远地区——包括保护工作滞后的公海——建立高度保护区。

▲ Abstract：

In this work, we derive fish size indicators from 17,411 stereo baited-video deployments to test for differences between pelagic and benthic responses to remoteness from human pressures and effectiveness of marine protected areas (MPAs). From records of 823,849 individual fish, we report divergent responses between systems, with pelagic size structure more profoundly eroded near human markets than benthic size structure, signifying greater vulnerability of pelagic systems to human pressure. Effective protection of benthic size structure can be achieved through MPAs placed near markets, thereby contributing to benthic habitat restoration and the recovery of associated fishes. By contrast, recovery of the world’s largest and most endangered fishes in pelagic systems requires the creation of highly protected areas in remote locations, including on the High Seas, where protection efforts lag.

A morphological basis for path-dependent evolution of visual systems

视觉系统路径依赖进化的形态学基础

▲ 作者：REBECCA M. VARNEY, DANIEL I. SPEISER et al.

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▲ 摘要：

在此，我们展示了最近在石鳖中进化了两次的两种类型的分布式视觉系统，证明了一种复杂特征的、快速且路径依赖的进化。石鳖可以进化出的视觉系统类型受到其壳板上感觉神经开口数量的限制。

开口较多的谱系进化出具有数千个眼点的视觉系统，而开口较少的谱系只能进化出数百个壳眼的视觉系统。这些由路径依赖形成的宏观进化结果既是确定性的，也是随机的，因为虽然其可能性是有限的，但并不是完全可预测的。

▲ Abstract：

Here, we show that two types of distributed visual systems recently evolved twice within chitons, demonstrating rapid and path-dependent evolution of a complex trait. The type of visual system that a chiton lineage can evolve is constrained by the number of openings for sensory nerves in its shell plates. Lineages with more openings evolve visual systems with thousands of eyespots, whereas those with fewer openings evolve visual systems with hundreds of shell eyes. These macroevolutionary outcomes shaped by path dependence are both deterministic and stochastic because possibilities are restricted yet not entirely predictable.

地球明升体育appEarth Science

Large-scale self-organization in dry turbulent atmospheres

干燥湍流大气中的大范围自组织情况

▲ 作者：ALEXANDROS ALEXAKIS, RAFFAELE MARINO et al.

▲ 链接：

http://www.science.org/doi/10.1126/science.adg8269

▲ 摘要：

湍流对流波动如何在行星大气中组织形成更大规模的结构，仍然是一个无法通过定量方法回答的问题。半个世纪前，在二维流体中提出了这个过程是逆级联结果的假设，但它是否适用于大气和海洋流动仍然存在激烈的争论，这阻碍了我们对行星系统能量平衡的理解。

我们使用空间分辨率为122882× 384点的直接数值模拟表明，旋转和分层流可以在三维空间中支持双向的能量级联，其罗斯贝与弗劳德数的比值与地球大气的比值相当。我们的结果表明，自发秩序可以在干燥的大气中通过逆级联到最大的空间尺度而产生。

▲ Abstract：

How turbulent convective fluctuations organize to form larger-scale structures in planetary atmospheres remains a question that eludes quantitative answers. The assumption that this process is the result of an inverse cascade was suggested half a century ago in two-dimensional fluids, but its applicability to atmospheric and oceanic flows remains heavily debated, hampering our understanding of the energy balance in planetary systems. We show using direct numerical simulations with spatial resolutions of 122882 × 384 points that rotating and stratified flows can support a bidirectional cascade of energy, in three dimensions, with a ratio of Rossby to Froude numbers comparable to that of Earth’s atmosphere. Our results establish that, in dry atmospheres, spontaneous order can arise through an inverse cascade to the largest spatial scales.

Anthropogenic climate change has influenced global river flow seasonality

人为气候变化影响了全球河流流量的季节性

▲ 作者：HONG WANG, JUNGUO LIU et al.

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▲ 摘要：

本研究引入了分配熵的使用，作为评估季节间流量—体积不均匀性的稳定措施，从而实现了全球范围分析。我们发现，约21%的长期河流监测站在季节流量分布上表现出了显著变化，但其中2/3与年平均流量趋势无关。

通过将数据驱动的径流重建与最先进的水文模拟相结合，我们确定了北部高纬度地区（北纬50°以上）河流流量季节性的明显减弱，这一现象与人为气候影响直接相关。

▲ Abstract：

This study introduces the use of apportionment entropy as a robust measure to assess flow-volume nonuniformity across seasons, enabling a global analysis. We found that ~21% of long-term river gauging stations exhibit significant alterations in seasonal flow distributions, but two-thirds of these are unrelated to trends in annual mean discharge. By combining a data-driven runoff reconstruction with state-of-the-art hydrological simulations, we identified a discernible weakening of river flow seasonality in northern high latitudes (above 50°N), a phenomenon directly linked to anthropogenic climate forcing.