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Spin squeezing of 10(11) atoms by prediction and retrodiction measurements 期刊论文
NATURE, 2020, 581 (7807) : 159-+
作者:  Lan, Jun;  Ge, Jiwan;  Yu, Jinfang;  Shan, Sisi;  Zhou, Huan;  Fan, Shilong;  Zhang, Qi;  Shi, Xuanling;  Wang, Qisheng;  Zhang, Linqi;  Wang, Xinquan
收藏  |  浏览/下载:7/0  |  提交时间:2020/07/03

The measurement sensitivity of quantum probes using N uncorrelated particles is restricted by the standard quantum limit(1), which is proportional to 1/root N. This limit, however, can be overcome by exploiting quantum entangled states, such as spin-squeezed states(2). Here we report the measurement-based generation of a quantum state that exceeds the standard quantum limit for probing the collective spin of 10(11) rubidium atoms contained in a macroscopic vapour cell. The state is prepared and verified by sequences of stroboscopic quantum non-demolition (QND) measurements. We then apply the theory of past quantum states(3,4) to obtain spin state information from the outcomes of both earlier and later QND measurements. Rather than establishing a physically squeezed state in the laboratory, the past quantum state represents the combined system information from these prediction and retrodiction measurements. This information is equivalent to a noise reduction of 5.6 decibels and a metrologically relevant squeezing of 4.5 decibels relative to the coherent spin state. The past quantum state yields tighter constraints on the spin component than those obtained by conventional QND measurements. Our measurement uses 1,000 times more atoms than previous squeezing experiments(5-10), with a corresponding angular variance of the squeezed collective spin of 4.6 x 10(-13) radians squared. Although this work is rooted in the foundational theory of quantum measurements, it may find practical use in quantum metrology and quantum parameter estimation, as we demonstrate by applying our protocol to quantum enhanced atomic magnetometry.


  
Video-based AI for beat-to-beat assessment of cardiac function 期刊论文
NATURE, 2020, 580 (7802) : 252-+
作者:  Pleguezuelos-Manzano, Cayetano;  Puschhof, Jens;  Huber, Axel Rosendahl;  van Hoeck, Arne;  Wood, Henry M.;  Nomburg, Jason;  Gurjao, Carino;  Manders, Freek;  Dalmasso, Guillaume;  Stege, Paul B.;  Paganelli, Fernanda L.;  Geurts, Maarten H.;  Beumer, Joep;  Mizutani, Tomohiro;  Miao, Yi;  van der Linden, Reinier;  van der Elst, Stefan;  Garcia, K. Christopher;  Top, Janetta;  Willems, Rob J. L.;  Giannakis, Marios;  Bonnet, Richard;  Quirke, Phil;  Meyerson, Matthew;  Cuppen, Edwin;  van Boxtel, Ruben;  Clevers, Hans
收藏  |  浏览/下载:117/0  |  提交时间:2020/07/03

A video-based deep learning algorithm-EchoNet-Dynamic-accurately identifies subtle changes in ejection fraction and classifies heart failure with reduced ejection fraction using information from multiple cardiac cycles.


Accurate assessment of cardiac function is crucial for the diagnosis of cardiovascular disease(1), screening for cardiotoxicity(2) and decisions regarding the clinical management of patients with a critical illness(3). However, human assessment of cardiac function focuses on a limited sampling of cardiac cycles and has considerable inter-observer variability despite years of training(4,5). Here, to overcome this challenge, we present a video-based deep learning algorithm-EchoNet-Dynamic-that surpasses the performance of human experts in the critical tasks of segmenting the left ventricle, estimating ejection fraction and assessing cardiomyopathy. Trained on echocardiogram videos, our model accurately segments the left ventricle with a Dice similarity coefficient of 0.92, predicts ejection fraction with a mean absolute error of 4.1% and reliably classifies heart failure with reduced ejection fraction (area under the curve of 0.97). In an external dataset from another healthcare system, EchoNet-Dynamic predicts the ejection fraction with a mean absolute error of 6.0% and classifies heart failure with reduced ejection fraction with an area under the curve of 0.96. Prospective evaluation with repeated human measurements confirms that the model has variance that is comparable to or less than that of human experts. By leveraging information across multiple cardiac cycles, our model can rapidly identify subtle changes in ejection fraction, is more reproducible than human evaluation and lays the foundation for precise diagnosis of cardiovascular disease in real time. As a resource to promote further innovation, we also make publicly available a large dataset of 10,030 annotated echocardiogram videos.


  
Tobacco smoking and somatic mutations in human bronchial epithelium 期刊论文
NATURE, 2020, 578 (7794) : 266-+
作者:  Sharma, Nikhil;  Flaherty, Kali;  Lezgiyeva, Karina;  Wagner, Daniel E.;  Klein, Allon M.;  Ginty, David D.
收藏  |  浏览/下载:33/0  |  提交时间:2020/07/03

Whole-genome sequencing of normal bronchial epithelium from 16 individuals shows that tobacco smoking increases genomic heterogeneity, mutational burden and driver mutations, whereas stopping smoking promotes replenishment of the epithelium with near-normal cells.


Tobacco smoking causes lung cancer(1-3), a process that is driven by more than 60 carcinogens in cigarette smoke that directly damage and mutate DNA(4,5). The profound effects of tobacco on the genome of lung cancer cells are well-documented(6-10), but equivalent data for normal bronchial cells are lacking. Here we sequenced whole genomes of 632 colonies derived from single bronchial epithelial cells across 16 subjects. Tobacco smoking was the major influence on mutational burden, typically adding from 1,000 to 10,000 mutations per cell  massively increasing the variance both within and between subjects  and generating several distinct mutational signatures of substitutions and of insertions and deletions. A population of cells in individuals with a history of smoking had mutational burdens that were equivalent to those expected for people who had never smoked: these cells had less damage from tobacco-specific mutational processes, were fourfold more frequent in ex-smokers than current smokers and had considerably longer telomeres than their more-mutated counterparts. Driver mutations increased in frequency with age, affecting 4-14% of cells in middle-aged subjects who had never smoked. In current smokers, at least 25% of cells carried driver mutations and 0-6% of cells had two or even three drivers. Thus, tobacco smoking increases mutational burden, cell-to-cell heterogeneity and driver mutations, but quitting promotes replenishment of the bronchial epithelium from mitotically quiescent cells that have avoided tobacco mutagenesis.


  
Temporal population variability in local forest communities has mixed effects on tree species richness across a latitudinal gradient 期刊论文
ECOLOGY LETTERS, 2019
作者:  Fung, Tak;  Chisholm, Ryan A.;  Anderson-Teixeira, Kristina;  Bourg, Norm;  Brockelman, Warren Y.;  Bunyavejchewin, Sarayudh;  Chang-Yang, Chia-Hao;  Chitra-Tarak, Rutuja;  Chuyong, George;  Condit, Richard;  Dattaraja, Handanakere S.;  Davies, Stuart J.;  Ewango, Corneille E. N.;  Fewless, Gary;  Fletcher, Christine;  Gunatilleke, C. V. Savitri;  Gunatilleke, I. A. U. Nimal;  Hao, Zhanqing;  Hogan, J. Aaron;  Howe, Robert;  Hsieh, Chang-Fu;  Kenfack, David;  Lin, YiChing;  Ma, Keping;  Makana, Jean-Remy;  McMahon, Sean;  McShea, William J.;  Mi, Xiangcheng;  Nathalang, Anuttara;  Ong, Perry S.;  Parker, Geoffrey;  Rau, E-Ping;  Shue, Jessica;  Su, Sheng-Hsin;  Sukumar, Raman;  Sun, I-Fang;  Suresh, Hebbalalu S.;  Tan, Sylvester;  Thomas, Duncan;  Thompson, Jill;  Valencia, Renato;  Vallejo, Martha I.;  Wang, Xugao;  Wang, Yunquan;  Wijekoon, Pushpa;  Wolf, Amy;  Yap, Sandra;  Zimmerman, Jess
收藏  |  浏览/下载:14/0  |  提交时间:2020/02/17
Biodiversity  environmental variance  extinction risk  stochastic model  storage effect  temporal niche partitioning  
Transmission of shocks and contagion from US to MENA equity markets: The role of oil and gas markets 期刊论文
ENERGY POLICY, 2019, 134
作者:  Abid, Ilyes;  Goutte, Stephane;  Guesmi, Khaled;  Jamali, Ibrahim
收藏  |  浏览/下载:5/0  |  提交时间:2020/02/17
Contagion  Gas prices  Oil prices  Multifactor model  Variance decomposition  Sensitivities  MENA  US  Russia  
Validating the Water Vapor Variance Similarity Relationship in the Interfacial Layer Using Observations and Large-Eddy Simulations 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2019
作者:  Osman, M. K.;  Turner, D. D.;  Heus, T.;  Wulfmeyer, V
收藏  |  浏览/下载:6/0  |  提交时间:2019/11/27
turbulence  water vapor variance  interfacial layer  similarity relationship  Raman lidar  
A new method to study inhomogeneities in climate records: Brownian motion or random deviations? 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2019, 39 (12) : 4769-4783
作者:  Lindau, Ralf;  Venema, Victor
收藏  |  浏览/下载:7/0  |  提交时间:2019/11/27
Brownian motion  climate stations  homogenization  number of breaks  random deviations  signal separation  spurious trends  variance of lag differences  
Uncertainty in climate projections and time of emergence of climate signals in the western Canadian Prairies 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2019, 39 (11) : 4358-4371
作者:  Barrow, Elaine M.;  Sauchyn, David J.
收藏  |  浏览/下载:8/0  |  提交时间:2019/11/27
CMIP5  natural variability  time of emergence  uncertainty  variance partitioning  
General seasonal phase-locking of variance and persistence: application to tropical pacific, north pacific and global ocean 期刊论文
CLIMATE DYNAMICS, 2019, 53: 2825-2842
作者:  Jin, Yishuai;  Liu, Zhengyu;  Rong, Xinyao
收藏  |  浏览/下载:6/0  |  提交时间:2019/11/27
Phase locking  Variance  Persistence  Growth rate  Noise forcing  
The adaptive potential of plant populations in response to extreme climate events 期刊论文
ECOLOGY LETTERS, 2019, 22 (5) : 866-874
作者:  Torres-Martinez, Lorena;  McCarten, Niall;  Emery, Nancy C.
收藏  |  浏览/下载:4/0  |  提交时间:2019/11/26
additive genetic variance  climate change  El Nino  extreme climate  Fisher'  s Fundamental Theorem of Natural Selection  Lasthenia fremontii  precipitation  vernal pools