《科学》（20190531出版）一周论文导读

翻译 | 宗华

Science, 31 May 2019, Vol. 364, No. 6443

《科学》2019年5月31日，第6443期364卷

物理学Physics

Imaging the electronic Wigner crystal in one dimension

在一维中对电子维格纳晶体进行成像

▲ 作者： Shapir, A. Hamo, S. Pecker, et al

▲ 链接：

https://science.sciencemag.org/content/364/6443/870

▲ 摘要：

尤金·维格纳在80多年前预测的电子量子晶体，仍是最难以捉摸的物质状态之一。

在本研究中，我们通过对一维维格纳晶体在真实空间中的电荷密度成像，对其进行了直接观察。

为了以最小的侵入性对碳纳米管的多体电子密度成像，我们利用另一个纳米管作为扫描电荷扰动。我们得到的一些一维电子的图像符合强相互作用晶体的理论预测。

晶体的量子性质出现在观察到的通过势垒的集体隧穿过程中。这些实验为小维格纳晶体的形成提供了直接的证据，并为通过成像真实空间中的多体密度研究其他脆弱相互作用态开辟了道路。

▲ Abstract

The quantum crystal of electrons, predicted more than 80 years ago by Eugene Wigner, remains one of the most elusive states of matter. In this study, we observed the one-dimensional Wigner crystal directly by imaging its charge density inreal space. To image, with minimal in vasiveness, the many-body electronic density of a carbon nanotube, we used another nanotube as a scanning-charge perturbation. The images we obtained of a few electrons confined in one dimension match the theoretical predictions for strongly interacting crystals. The quantum nature of the crystal emerges in the observed collective tunneling through a potential barrier. These experiments provide the direct evidence fort he formation of small Wigner crystals and open the way for studying other fragile interacting states by imaging their many-body density in real space.

Observation of parity-time symmetry breaking in a single-spin system

在单自旋系统中对宇称—时间对称性破缺的观察

▲ 作者：Yang Wu, Wenquan Liu, Jianpei Geng, et al

▲ 链接：

https://science.sciencemag.org/content/364/6443/878

▲ 摘要：

控制单自旋系统的演化是量子计算和量子传感的关键。科学家利用具有奇异性质的宇称—时间对称哈密顿量理论，研究了量子系统的动力学。

尽管宇称—时间对称性已在经典系统中得以研究，但在单个量子系统中对它的观测仍难以捉摸。

本文提出了一种将一般宇称—时间对称哈密顿量扩大为厄密顿量的方法。利用金刚石中单个氮空位中心，从未被破坏到被破坏的PTPT对称区域，各种量子状态的演化均得到观测。

▲ Abstract

Steering the evolution of single spin systems is crucial for quantum computing and quantum sensing. The dynamics of quantum systems has been theoretically investigated with parity-time–symmetric Hamiltonians exhibiting exotic properties. Although parity-time symmetry has been explored in classical systems, its observation ina single quantum system remains elusive. We developed a method to dilate a general parity-time–symmetric Hamiltonian into a Hermitian one. The quantum state evolutions ranging from regions of unbroken to broken PTPT symmetry have been observed with a single nitrogen-vacancy center in diamond. Owing to the universality of the dilation method, our result provides a route for further exploiting and understanding the exotic properties of parity-time symmetric Hamiltonian in quantum systems.

 

生理学Physiology

Insular cortex processes aversive somatosensory information and is crucial for threat learning

岛叶皮层处理令人厌恶的躯体感觉信息，对威胁学习至关重要

▲ 作者：Emmanuelle Berret, Michael Kintscher, Shriya Palchaudhuri, et al

▲ 链接：

https://science.sciencemag.org/content/364/6443/eaaw0474

▲ 摘要：

了解威胁对生存至关重要。在威胁学习过程中，无害的感觉知觉如语调，与令人厌恶的刺激（如轻微的足部电击）相结合时，会获得情感上的意义。

杏仁核对威胁记忆的形成至关重要，但人们对于处理令人厌恶的躯体感觉信息的上游大脑区域一直知之甚少。

在小鼠中施加光遗传学技术，我们发现足部电击时后岛叶的沉默可减少急性恐惧行为，并且损害1天的威胁记忆。

岛叶皮质神经元对足电击作出反应，在学习威胁时获得对音调的反应，并投射出不同的杏仁核分裂来驱动急性恐惧和威胁记忆的形成。因此，后岛叶向杏仁核传递令人厌恶的足电击信息，对了解环境中的潜在危险至关重要。

▲ Abstract

Learning about threats is essential for survival. During threat learning, an innocuous sensory percept such as a tone acquires an emotional meaning when paired with an aversive stimulus such as a mild foot shock. The amygdala is critical for threat memory formation, but little is known about upstream brain areas that process aversive somatosensory information. Using optogenetic techniques in mice, we found that silencing of the posterior insula during footshock reduced acute fear behavior and impaired 1-day threat memory. Insular cortex neurons respond to footshocks, acquire responses to tones during threat learning, and project to distinct amygdala divisions to drive acute fear versus threat memory formation. Thus, the posterior insula conveys aversive footshock information to the amygdala and is crucial for learning about potential dangers in the environment.

Oligogenic inheritance of a human heart disease involving a genetic modifier

一种人类心脏病的低基因遗传涉及一种遗传修饰因子

▲ 作者：Casey A. Gifford1,2, Sanjeev S. Ranade1,2, Ryan Samarakoon, et al

▲ 链接：

https://science.sciencemag.org/content/364/6443/865

▲ 摘要：

复杂的遗传机制被认为是许多人类疾病的基础，但这一模型的实验验证一直难以捉摸。

这里，我们证明，人类心脏异常可以由罕见的、遗传的杂合突变组合引起。一个核家系的全外显子组测序显示，从儿童起患有心肌病的3个后代遗传了3种错义突变的MKL2、MYH7和NKX2-5基因单核苷酸变异。

MYH7和MKL2变异继承自受影响的无症状父亲，罕见的NKX2-5变异（小等位基因频率0.0012）则遗传自未受影响的母亲。

我们利用CRISPR-Cas9产生编码同源变异的小鼠，发现这3种变异的复合杂合性能再现人类疾病的表型。

▲ Abstract

Complex genetic mechanisms are thought to underlie many human diseases, yet experimental proof of this model has been elusive. Here, we show that a human cardiac anomaly can be caused by a combination of rare, inherited heterozygous mutations. Whole-exome sequencing of a nuclear family revealed that three offspring with childhood-onset cardiomyopathy had inherited three missense single-nucleotide variants in the MKL2, MYH7, and NKX2-5 genes. The MYH7 and MKL2 variants were inherited from the affected, a symptomatic father and the rare NKX2-5 variant (minor allele frequency, 0.0012) from the unaffected mother. We used CRISPR-Cas9 to generate mice encoding the orthologous variants and found that compound heterozygosity for all three variants recapitulated the human disease phenotype.

 

生态学Ecology

Transgenic Metarhizium rapidly kills mosquitoes in a malaria-endemic region of Burkina Faso

在布基纳法索疟疾流行地区，转基因绿僵菌能迅速杀死蚊虫

▲ 作者：Brian Lovett, Etienne Bilgo, Souro Abel Millogo, et al

▲ 链接：

https://science.sciencemag.org/content/364/6443/894

▲ 摘要：

疟疾控制工作需要实施管理杀虫剂耐药性的新技术。平沙绿僵菌为强效的昆虫选择性毒素提供了一种有效的蚊子特异性传递系统。

在疟疾流行的布吉纳法索Soumousso地区一个名为MosquitoSphere的受控、近似自然环境中开展的半现场试验证实，一种昆虫特异性毒素（杂交）的表达增加了真菌杀伤力以及抗杀虫剂的蚊虫从某个地方被清除的可能性。

此外，由于杂交表达平沙绿僵菌在极低的孢子剂量下有效，因此其药效比未变性的绿僵菌持续时间更长。

针对蚊子的转基因绿僵菌的应用可能会很快（取决于适当的注册），同时其产品可与现有的化学控制策略协同集成，以避免对杀虫剂产生抗药性。

▲ Abstract

Malaria control efforts require implementation of new technologies that manage insecticide resistance. Metarhizium pingshaense provides an effective, mosquito-specific delivery system for potent insect-selective toxins. A semifield trial in a Mosquito Sphere (a contained, near-natural environment) in Soumousso, a region of Burkina Faso where malaria is endemic, confirmed that the expression of aninsect-specific toxin (Hybrid) increased fungal lethality and the likelihood that insecticide-resistant mosquitoes would be eliminated from a site. Also, as Hybrid-expressing M. pingshaense is effective at very low spore doses, its efficacy lasted longer than that of the unmodified Metarhizium. Deployment of transgenic Metarhizium against mosquitoes could (subject to appropriate registration) be rapid, with products that could synergistically integrate with existing chemical control strategies to avert insecticide resistance.

The uncertain future of protected lands and waters

受保护土地和水域前途未卜

▲ 作者：Rachel E. Golden Kroner, Siyu Qin, Carly N. Cook, et al

▲ 链接：

https://science.sciencemag.org/content/364/6443/881

▲ 摘要：

保护区旨在永久保护生物多样性，但有证据表明，广泛的法律变化破坏了保护区的持久性和有效性。

我们记录了这些法律变化——美国和亚马逊国家的保护区降级、规模缩小及退化（PADDD）事件，并汇编了全球可用的数据。

美国和亚马逊国家的政府分别实施了269项和440项PADDD事件。

1892~2018年，73个国家共实施了3749起 PADDD事件，使519857平方公里土地不再受到保护；另外减缓了针对165972平方公里保护区的规定；其中， 78%的事件是2000年以来实施的。

大多数PADDD活动（62%）与工业规模的资源开采和开发有关，这表明PADDD可能损害生物多样性保护目标。

▲ Abstract

Protected areas are intended to safeguard biodiversity in perpetuity, yet evidence suggests that widespread legal changes undermine protected area durability and efficacy. We documented these legal changes—protected area downgrading, downsizing, and degazettement (PADDD) events—in the United States and Amazonian countries and compiled available data globally. Governments of the United States and Amazonian countries enacted 269 and 440 PADDD events, respectively. Between1892 and 2018, 73 countries enacted 3749 PADDD events, removing 519,857 square kilometers from protection and tempering regulations in an additional 1,659,972 square kilometers; 78% of events were enacted since 2000. Most PADDD events(62%) are associated with industrial-scale resource extraction and development, suggesting that PADDD may compromise biodiversity conservation objectives.

 

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