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41.
Stark A Lin MF Kheradpour P Pedersen JS Parts L Carlson JW Crosby MA Rasmussen MD Roy S Deoras AN Ruby JG Brennecke J;Harvard FlyBase curators;Berkeley Drosophila Genome Project Hodges E Hinrichs AS Caspi A Paten B Park SW Han MV Maeder ML Polansky BJ Robson BE Aerts S van Helden J Hassan B Gilbert DG Eastman DA Rice M Weir M Hahn MW Park Y Dewey CN Pachter L Kent WJ Haussler D Lai EC Bartel DP Hannon GJ Kaufman TC Eisen MB Clark AG Smith D Celniker SE Gelbart WM Kellis M 《Nature》2007,450(7167):219-232
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Lai CW Kim NY Utsunomiya S Roumpos G Deng H Fraser MD Byrnes T Recher P Kumada N Fujisawa T Yamamoto Y 《Nature》2007,450(7169):529-532
The effect of quantum statistics in quantum gases and liquids results in observable collective properties among many-particle systems. One prime example is Bose-Einstein condensation, whose onset in a quantum liquid leads to phenomena such as superfluidity and superconductivity. A Bose-Einstein condensate is generally defined as a macroscopic occupation of a single-particle quantum state, a phenomenon technically referred to as off-diagonal long-range order due to non-vanishing off-diagonal components of the single-particle density matrix. The wavefunction of the condensate is an order parameter whose phase is essential in characterizing the coherence and superfluid phenomena. The long-range spatial coherence leads to the existence of phase-locked multiple condensates in an array of superfluid helium, superconducting Josephson junctions or atomic Bose-Einstein condensates. Under certain circumstances, a quantum phase difference of pi is predicted to develop among weakly coupled Josephson junctions. Such a meta-stable pi-state was discovered in a weak link of superfluid 3He, which is characterized by a 'p-wave' order parameter. The possible existence of such a pi-state in weakly coupled atomic Bose-Einstein condensates has also been proposed, but remains undiscovered. Here we report the observation of spontaneous build-up of in-phase ('zero-state') and antiphase ('pi-state') 'superfluid' states in a solid-state system; an array of exciton-polariton condensates connected by weak periodic potential barriers within a semiconductor microcavity. These in-phase and antiphase states reflect the band structure of the one-dimensional polariton array and the dynamic characteristics of metastable exciton-polariton condensates. 相似文献
43.
设R是有1的交换环,L是R上的辛代数或正交代数,h是L的极大环面子代数,b是L中包含h的标准Borel子代数.在2∈R可逆的条件下,本文详细描述了b与L之间的中间李代数,并且证明这些中间李代数的导子都是内导子. 相似文献
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针对传统钢材表面缺陷检测方法易出现误检、漏检和部分缺陷种类检测精度低等问题,本文设计了一种钢材表面缺陷网络YOLOv5s-FCS。首先本文引用了FReLU激活函数构建了卷积模块CBF,有效增强了网络的空间解析能力,优化了网络检测精度;其次,本文将坐标注意力机制嵌入到网络的neck部分来增强网络特征融合的能力,从而使网络能够提取更加丰富的特征信息;最后,将YOLOv5s的损失函数替换为SIoU loss,提高了预测框的回归精度。通过在NEU-DET数据集上进行消融实验、可视化对比实验,结果表明,YOLOv5s-FCS网络的mAP值达到了0.747,相较于原YOLOv5s网络提高了8.3%,相较于YOLOv3网络提高了11.8%,相较于YOLOXs网络提高了4.2%,相较于YOLOv6s提高了1.4%,验证了该方法的可行性、有效性。 相似文献
46.
As a representative emerging financial market, the Chinese stock market is more prone to volatility because of investor sentiment. It is reasonable to use efficient predictive methods to analyze the influence of investor sentiment on stock price forecasting. This paper conducts a comparative study about the predictive performance of artificial neural network, support vector regression (SVR) and autoregressive integrated moving average and selects SVR to study the asymmetry effect of investor sentiment on different industry index predictions. After studying the relevant financial indicators, the results divide the Shenwan first-class industries into two types and show that the industries affected by investor sentiment are composed of young companies with high growth and high operative pressure and there are a great number of investment bubbles in those companies. 相似文献
47.
Generation of CRISPR/Cas9-mediated gene-targeted pigs via somatic cell nuclear transfer 总被引:1,自引:1,他引:0
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Prevotella bivia is associated with pelvic inflammatory disease. A 77-year-old man developed a rapidly growing chest wall abscess due to P. bivia within days. He underwent surgical resection of the infected area; his postoperative course was uneventful. This is the first case of chest wall abscess due to P. bivia infection. Its correct diagnosis cannot be underestimated because fulminant infections can occur in aged or immunocompromised patients if treated incorrectly. Prompt, appropriate surgical management, and antibiotic therapy affect treatment outcome. 相似文献
49.
多样价值取向的产生是全球一体化所引起的剧烈碰撞中的必然现象,它代表着社会不同阶层、集团的经济利益、政治诉求和意识形态倾向。尽管多样价值取向会给社会带来一定的消极影响,但是也有其存在的合理性。总结历史经验教训,探求出一条以核心价值体系引领多样价值取向的道路,可以有效实现良性共存,共创和谐社会。 相似文献
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