編譯 | 馮維維
Science, 17 APRIL 2020, Vol 368, Issue 6488
《科學》2020年4月17日，第368卷，6488期
生態學Ecology
Meeting fisheries, ecosystem function, and biodiversity goals in a human-dominated world
實現漁業、生態系統功能和生物多樣性目標
▲ 作者：Joshua E. Cinner, Jessica Zamborain-Mason, David Mouillot
▲ 鏈接：
https://science.sciencemag.org/content/368/6488/307
▲ 摘要
全球範圍內珊瑚礁的減少，需要針對性的管理方面的解決方案，以維持珊瑚礁和依賴珊瑚礁的人們的生計。然而，人們對不同珊瑚礁管理工具在實現多種社會和生態目標的作用知之甚少。
隨著人類壓力梯度的不同，實現漁業、生態功能和生物多樣性綜合目標的可能性是非線性的，在實施管理中發生相對較小的變化可能對是否能實現這些目標會產生重大影響。
重要的是，管理可以為大多數珊瑚礁的漁業和生態功能提供大量的保護效益，但不能實現生物多樣性的目標，因為它們的狀態已經退化，而且面臨著人類的壓力。
▲ Abstract
The worldwide decline of coral reefs necessitates targeting management solutions that can sustain reefs and the livelihoods of the people who depend on them. However, little is known about the context in which different reef management tools can help to achieve multiple social and ecological goals. Because of nonlinearities in the likelihood of achieving combined fisheries, ecological function, and biodiversity goals along a gradient of human pressure, relatively small changes in the context in which management is implemented could have substantial impacts on whether these goals are likely to be met. Critically, management can provide substantial conservation benefits to most reefs for fisheries and ecological function, but not biodiversity goals, given their degraded state and the levels of human pressure they face.
Large contribution from anthropogenic warming to an emerging North American megadrought
北美乾旱由人為疊加自然因素驅動
▲ 作者：A. Park Williams, Edward R. Cook, Jason E. Smerdon, Ben Livneh, etc.
▲ 鏈接：
https://science.sciencemag.org/content/368/6488/314
▲ 摘要
21世紀，北美西南部持續的嚴重乾旱讓人們將其與中世紀的特大幹旱相提並論，並對人為因素對氣候變化的作用提出質疑。
作者使用水文模型和一棵擁有1200年曆史的樹木的新年輪重建夏季的土壤水分，以此證明2000年至2018年北美西南的乾旱是自公元800年以來第二次最嚴重的持續19年的乾旱，僅次於16世紀後期的特大幹旱。
2000年至2018年的超級大略樣的土壤溼度軌跡，是由人為原因造成的變暖導致的乾旱疊加自然變異驅動的。
▲ Abstract
Severe and persistent 21st-century drought in southwestern North America (SWNA) motivates comparisons to medieval megadroughts and questions about the role of anthropogenic climate change. We use hydrological modeling and new 1200-year tree-ring reconstructions of summer soil moisture to demonstrate that the 2000–2018 SWNA drought was the second driest 19-year period since 800 CE, exceeded only by a late-1500s megadrought. The megadrought-like trajectory of 2000–2018 soil moisture was driven by natural variability superimposed on drying due to anthropogenic warming.
化學Chemistry
A dual light-driven palladium catalyst: Breaking the barriers in carbonylation reactions
照亮來回的路
▲ 作者：Gerardo M. Torres, Yi Liu, Bruce A. Arndtsen
▲ 鏈接：
https://science.sciencemag.org/content/368/6488/318
▲ 摘要
催化劑通過打破現有的化學鍵然後形成新的化學鍵來加速化學反應。
通常，有利於第一個過程的因素會攪亂第二個過程，從而限制了催化劑的通用性。作者發現，鈀配合物的可見光激發可以促進碳-鹵素鍵的斷裂和形成。
該反應通過多種烷基或芳基溴化物和碘化物的羰基化反應而形成酸氯化物。這些產物反過來又能進一步反應形成酰胺和酯。
▲ Abstract
Catalysts accelerate chemical reactions by breaking existing bonds and then forming new ones. Often, the factors that favor the first process can muddle the second one, constraining a catalyst's generality. Torres et al. found that visible light excitation of a palladium complex can facilitate both the breaking and making of carbon-halogen bonds. The reaction specifically forms acid chlorides by carbonylation of a wide variety of alkyl or aryl bromides and iodides. These products in turn can react further to form amides and esters.
Balancing volumetric and gravimetric uptake in highly porous materials for clean energy
平衡用於清潔能源的材料的體積和重量
▲ 作者：Zhijie Chen, Penghao Li, Ryther Anderson, Xingjie Wang, Xuan Zhang, Lee Robison, Omar K. Farha
▲ 鏈接：
https://science.sciencemag.org/content/368/6488/297
▲ 摘要
在交通工具上儲存甲烷和氫氣的壓力通常被限制在100巴（1巴=10萬帕）以內，因為使用的是輕量容器，但隨著吸收材料的使用，其儲存量可以增加。
高效的存儲和傳輸需要容量和重量的平衡。作者設計了一個三鋁節點的金屬有機框架和一個大型六齒芳香鏈接器，優化了這兩個參數。
這種材料超過了美國能源部為甲烷設定的目標，其可輸送氫的能力（按重量計）為14%。
▲ Abstract
The pressure for onboard storage of methane and hydrogen on vehicles is usually limited to 100 bar for the use of lightweight containers, but the amount stored can be increased with the use of absorbent materials. Efficient storage and delivery require a balance of volumetric and gravimetric storage. Chen et al. designed a metal-organic framework with trialuminum nodes and a large hexadentate aromatic linker that optimizes both parameters. This material surpassed the U.S. Department of Energy targets for methane and had a deliverable capacity of 14% by weight for hydrogen.
物理學Physics
Topological funneling of light
拓撲光漏斗
▲ 作者：Sebastian Weidemann, Mark Kremer, Tobias Helbig, Tobias Hofmann, etc.
▲ 鏈接：
https://science.sciencemag.org/content/368/6488/311
▲ 摘要
耗散是非厄米系統的一個普遍特徵。但非厄米度並非不可避免的麻煩，它可以被精確地控制，因此可以用於複雜的應用，比如靈敏度更高的光學傳感器。
作者通過裁減最近鄰耦合的各向異性來實現一個非厄米光子晶格。界面的出現導致整個本徵模態譜的完全崩潰，導致界面上所有模態的指數局部化。
因此，晶格內的任何光場，無論其形狀和輸入位置，都向這個界面運動。基於這種被稱為“非厄米表皮效應”的拓撲現象，作者展示了一個高效的光漏斗。
▲ Abstract
Dissipation is a general feature of non-Hermitian systems. But rather than being an unavoidable nuisance, non-Hermiticity can be precisely controlled and hence used for sophisticated applications, such as optical sensors with enhanced sensitivity. In our work, we implement a non-Hermitian photonic mesh lattice by tailoring the anisotropy of the nearest-neighbor coupling. The appearance of an interface results in a complete collapse of the entire eigenmode spectrum, leading to an exponential localization of all modes at the interface. As a consequence, any light field within the lattice travels toward this interface, irrespective of its shape and input position. On the basis of this topological phenomenon, called the “non-Hermitian skin effect,” we demonstrate a highly efficient funnel for light.
生物學Biology
Temperature-dependent sex determination is mediated by pSTAT3 repression of Kdm6b
溫度影響性別設定
▲ 作者：Ceri Weber, Yingjie Zhou, Jong Gwan Lee, Loren L. Looger, etc.
▲ 鏈接：
https://science.sciencemag.org/content/368/6488/303
▲ 摘要
在許多爬行動物中，性別是由孵化卵時的巢溫決定的。溫度調節一種稱為Kdm6b的表觀遺傳修飾基因的表達，該基因負責睪丸的發育。
然而，這一因子的溫度和性別特異性表達之間的分子聯繫以前是未知的。
作者發現了溫度與Kdm6b的關鍵調控因子激活之間的聯繫，該調控因子被稱為信號轉換器和轉錄激活因子3 （STAT3）。
在溫度更高的生產雌性的Ca2+流入後，STAT3會磷酸化，讓Kdm6b轉錄沉默，從而抑制睪丸發育。
▲ Abstract
In many reptiles, sex is determined by nest temperature during egg incubation. Temperature regulates the expression of an epigenetic modifier gene called Kdm6b, which is responsible for testis development. However, the molecular connection between temperature and sex-specific expression of this factor was previously unknown. Weber et al. have identified a link between temperature and the activation of a key regulator of Kdm6b called signal transducer and activator of transcription 3 (STAT3). After an influx of Ca2+ at the warmer, female-producing temperature, STAT3 is phosphorylated and silences Kdm6b transcription to repress testis development.
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