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Search and rescue at sea aided by hidden flow structures 期刊论文
NATURE COMMUNICATIONS, 2020, 11 (1)
作者:  Serra, Mattia;  Sathe, Pratik;  Rypina, Irina;  Kirincich, Anthony;  Ross, Shane D.;  Lermusiaux, Pierre;  Allen, Arthur;  Peacock, Thomas;  Haller, George
收藏  |  浏览/下载:5/0  |  提交时间:2020/06/01
The water lily genome and the early evolution of flowering plants 期刊论文
NATURE, 2020, 577 (7788) : 79-+
作者:  Zhang, Liangsheng;  Chen, Fei;  Zhang, Xingtan;  Li, Zhen;  Zhao, Yiyong;  Lohaus, Rolf;  Chang, Xiaojun;  Dong, Wei;  Ho, Simon Y. W.;  Liu, Xing;  Song, Aixia;  Chen, Junhao;  Guo, Wenlei;  Wang, Zhengjia;  Zhuang, Yingyu;  Wang, Haifeng;  Chen, Xuequn;  Hu, Juan;  Liu, Yanhui;  Qin, Yuan;  Wang, Kai;  Dong, Shanshan;  Liu, Yang;  Zhang, Shouzhou;  Yu, Xianxian;  Wu, Qian;  Wang, Liangsheng;  Yan, Xueqing;  Jiao, Yuannian;  Kong, Hongzhi;  Zhou, Xiaofan;  Yu, Cuiwei;  Chen, Yuchu;  Li, Fan;  Wang, Jihua;  Chen, Wei;  Chen, Xinlu;  Jia, Qidong;  Zhang, Chi;  Jiang, Yifan;  Zhang, Wanbo;  Liu, Guanhua;  Fu, Jianyu;  Chen, Feng;  Ma, Hong;  Van de Peer, Yves;  Tang, Haibao
收藏  |  浏览/下载:13/0  |  提交时间:2020/07/03

Water lilies belong to the angiosperm order Nymphaeales. Amborellales, Nymphaeales and Austrobaileyales together form the so-called ANA-grade of angiosperms, which are extant representatives of lineages that diverged the earliest from the lineage leading to the extant mesangiosperms(1-3). Here we report the 409-megabase genome sequence of the blue-petal water lily (Nymphaea colorata). Our phylogenomic analyses support Amborellales and Nymphaeales as successive sister lineages to all other extant angiosperms. The N. colorata genome and 19 other water lily transcriptomes reveal a Nymphaealean whole-genome duplication event, which is shared by Nymphaeaceae and possibly Cabombaceae. Among the genes retained from this whole-genome duplication are homologues of genes that regulate flowering transition and flower development. The broad expression of homologues of floral ABCE genes in N. colorata might support a similarly broadly active ancestral ABCE model of floral organ determination in early angiosperms. Water lilies have evolved attractive floral scents and colours, which are features shared with mesangiosperms, and we identified their putative biosynthetic genes in N. colorata. The chemical compounds and biosynthetic genes behind floral scents suggest that they have evolved in parallel to those in mesangiosperms. Because of its unique phylogenetic position, the N. colorata genome sheds light on the early evolution of angiosperms.


  
Causal networks for climate model evaluation and constrained projections 期刊论文
NATURE COMMUNICATIONS, 2020, 11 (1)
作者:  Nowack, Peer;  Runge, Jakob;  Eyring, Veronika;  Haigh, Joanna D.
收藏  |  浏览/下载:14/0  |  提交时间:2020/05/13
Operation of a silicon quantum processor unit cell above one kelvin 期刊论文
NATURE, 2020, 580 (7803) : 350-+
作者:  Han, Kyuho;  Pierce, Sarah E.;  Li, Amy;  Spees, Kaitlyn;  Anderson, Grace R.;  Seoane, Jose A.;  Lo, Yuan-Hung;  Dubreuil, Michael;  Olivas, Micah;  Kamber, Roarke A.;  Wainberg, Michael;  Kostyrko, Kaja;  Kelly, Marcus R.;  Yousefi, Maryam;  Simpkins, Scott W.;  Yao, David
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/03

Quantum computers are expected to outperform conventional computers in several important applications, from molecular simulation to search algorithms, once they can be scaled up to large numbers-typically millions-of quantum bits (qubits)(1-3). For most solid-state qubit technologies-for example, those using superconducting circuits or semiconductor spins-scaling poses a considerable challenge because every additional qubit increases the heat generated, whereas the cooling power of dilution refrigerators is severely limited at their operating temperature (less than 100 millikelvin)(4-6). Here we demonstrate the operation of a scalable silicon quantum processor unit cell comprising two qubits confined to quantum dots at about 1.5 kelvin. We achieve this by isolating the quantum dots from the electron reservoir, and then initializing and reading the qubits solely via tunnelling of electrons between the two quantum dots(7-9). We coherently control the qubits using electrically driven spin resonance(10,11) in isotopically enriched silicon(12 28)Si, attaining single-qubit gate fidelities of 98.6 per cent and a coherence time of 2 microseconds during '  hot'  operation, comparable to those of spin qubits in natural silicon at millikelvin temperatures(13-16). Furthermore, we show that the unit cell can be operated at magnetic fields as low as 0.1 tesla, corresponding to a qubit control frequency of 3.5 gigahertz, where the qubit energy is well below the thermal energy. The unit cell constitutes the core building block of a full-scale silicon quantum computer and satisfies layout constraints required by error-correction architectures(8),(17). Our work indicates that a spin-based quantum computer could be operated at increased temperatures in a simple pumped He-4 system (which provides cooling power orders of magnitude higher than that of dilution refrigerators), thus potentially enabling the integration of classical control electronics with the qubit array(18,19).


  
Coherent electrical control of a single high-spin nucleus in silicon 期刊论文
NATURE, 2020, 579 (7798) : 205-+
作者:  Dedoussi, Irene C.;  Eastham, Sebastian D.;  Monier, Erwan;  Barrett, Steven R. H.
收藏  |  浏览/下载:10/0  |  提交时间:2020/07/03

Nuclear spins are highly coherent quantum objects. In large ensembles, their control and detection via magnetic resonance is widely exploited, for example, in chemistry, medicine, materials science and mining. Nuclear spins also featured in early proposals for solid-state quantum computers(1) and demonstrations of quantum search(2) and factoring(3) algorithms. Scaling up such concepts requires controlling individual nuclei, which can be detected when coupled to an electron(4-6). However, the need to address the nuclei via oscillating magnetic fields complicates their integration in multi-spin nanoscale devices, because the field cannot be localized or screened. Control via electric fields would resolve this problem, but previous methods(7-9) relied on transducing electric signals into magnetic fields via the electron-nuclear hyperfine interaction, which severely affects nuclear coherence. Here we demonstrate the coherent quantum control of a single Sb-123 (spin-7/2) nucleus using localized electric fields produced within a silicon nanoelectronic device. The method exploits an idea proposed in 1961(10) but not previously realized experimentally with a single nucleus. Our results are quantitatively supported by a microscopic theoretical model that reveals how the purely electrical modulation of the nuclear electric quadrupole interaction results in coherent nuclear spin transitions that are uniquely addressable owing to lattice strain. The spin dephasing time, 0.1 seconds, is orders of magnitude longer than those obtained by methods that require a coupled electron spin to achieve electrical driving. These results show that high-spin quadrupolar nuclei could be deployed as chaotic models, strain sensors and hybrid spin-mechanical quantum systems using all-electrical controls. Integrating electrically controllable nuclei with quantum dots(11,12) could pave the way to scalable, nuclear- and electron-spin-based quantum computers in silicon that operate without the need for oscillating magnetic fields.


  
The long road to fairer algorithms (vol 578, pg 34, 2020) 期刊论文
NATURE, 2020, 578 (7793) : 37-37
作者:  Song, Eric;  Mao, Tianyang;  Dong, Huiping;  Boisserand, Ligia Simoes Braga;  Antila, Salli;  Bosenberg, Marcus;  Alitalo, Kari;  Thomas, Jean-Leon;  Iwasaki, Akiko
收藏  |  浏览/下载:5/0  |  提交时间:2020/07/03
Algorithms on regulatory lockdown in medicine 期刊论文
SCIENCE, 2019, 366 (6470) : 1202-1204
作者:  Babic, Boris;  Gerke, Sara;  Evgeniou, Theodoros;  Cohen, I. Glenn
收藏  |  浏览/下载:1/0  |  提交时间:2020/02/17
Preventing undesirable behavior of intelligent machines 期刊论文
SCIENCE, 2019, 366 (6468) : 999-+
作者:  Thomas, Philip S.;  da Silva, Bruno Castro;  Barto, Andrew G.;  Giguere, Stephen;  Brun, Yuriy;  Brunskill, Emma
收藏  |  浏览/下载:10/0  |  提交时间:2020/02/17
Genomic architecture and introgression shape a butterfly radiation 期刊论文
SCIENCE, 2019, 366 (6465) : 594-+
作者:  Edelman, Nathaniel B.;  Frandsen, Paul B.;  Miyagi, Michael;  Clavijo, Bernardo;  Davey, John;  Dikow, Rebecca B.;  Garcia-Accinelli, Gonzalo;  Van Belleghem, Steven M.;  Patterson, Nick;  Neafsey, Daniel E.;  Challis, Richard;  Kumar, Sujai;  Moreira, Gilson R. P.;  Salazar, Camilo;  Chouteau, Mathieu;  Counterman, Brian A.;  Papa, Riccardo;  Blaxter, Mark;  Reed, Robert D.;  Dasmahapatra, Kanchon K.;  Kronforst, Marcus;  Joron, Mathieu;  Jiggins, Chris D.;  McMillan, W. Owen;  Di Palma, Federica;  Blumberg, Andrew J.;  Wakeley, John;  Jaffe, David;  Mallet, James
收藏  |  浏览/下载:10/0  |  提交时间:2020/02/17
Dissecting racial bias in an algorithm used to manage the health of populations 期刊论文
SCIENCE, 2019, 366 (6464) : 447-+
作者:  Obermeyer, Ziad;  Powers, Brian;  Vogeli, Christine;  Mullainathan, Sendhil
收藏  |  浏览/下载:4/0  |  提交时间:2019/11/27