一种新的用于图像检索的颜色一空间特征

为了解决图像检索中颜色直方图无法描述颜色空间位置信息的问题,提出了一种新的基于色彩量化的凸壳内角直方图特征.针对量化后HSV颜色空间中某一具体量化颜色值对应像素点的空间分布,首先计算包含这些像素点位置信息的凸壳,并对该凸壳的所有内角建立直方图.然后处理所有量化颜色值提取整幅图像的凸壳内角直方图特征.将该方法和一些文献中提出的方法进行的比较实验结果表明:提出的新特征可以有效地描述颜色空间位置信息,在查准率和查全率指标上均优于已有文献中的一些方法.     

当代自由主义的困境——论哈耶克、约翰·顿、罗尔斯和罗蒂

非常感谢高瑞泉教授的邀请,使我十分荣幸能有机会来华东师范大学主持第九期大夏讲坛。今天我演讲的题目是“当代自由主义的困境——论哈耶克、约翰&;#183;顿、罗尔斯和罗蒂”。正如在座诸位知道的那样,这个演讲其实是我这次在华东师范大学系列演讲的第三讲。前两讲的题目分别是“人类学文化观念中的知识论意蕴”和“文化观念中的知识论意蕴：中西哲学的讨论”,其出发点就是去探讨如何以哲学思辩的方式来会通中西。     

让我们更多地认识城市与城市研究(二)

本文是美国圣地亚哥大学教授詹姆斯·A·克莱普2008年4月在北京城市学院的演讲,演讲共三场。为便于读者全面地理解克莱普教授的演讲内容,全部演讲内容被编译成一篇。本文是根据演讲记录稿整理后,经克莱普教授本人审定英文稿编译。     

A CRISPR/Cas12a-empowered surface plasmon resonance platform for rapid and specific diagnosis of the Omicron variant of SARS-CoV-2

The outbreak of the COVID-19 pandemic was partially due to the challenge of identifying asymptomatic and presymptomatic carriers of the virus, and thus highlights a strong motivation for diagnostics with high sensitivity that can be rapidly deployed. On the other hand, several concerning SARS-CoV-2 variants, including Omicron, are required to be identified as soon as the samples are identified as ‘positive’. Unfortunately, a traditional PCR test does not allow their specific identification. Herein, for the first time, we have developed MOPCS (Methodologies of Photonic CRISPR Sensing), which combines an optical sensing technology-surface plasmon resonance (SPR) with the ‘gene scissors’ clustered regularly interspaced short palindromic repeat (CRISPR) technique to achieve both high sensitivity and specificity when it comes to measurement of viral variants. MOPCS is a low-cost, CRISPR/Cas12a-system-empowered SPR gene-detecting platform that can analyze viral RNA, without the need for amplification, within 38 min from sample input to results output, and achieve a limit of detection of 15 fM. MOPCS achieves a highly sensitive analysis of SARS-CoV-2, and mutations appear in variants B.1.617.2 (Delta), B.1.1.529 (Omicron) and BA.1 (a subtype of Omicron). This platform was also used to analyze some recently collected patient samples from a local outbreak in China, identified by the Centers for Disease Control and Prevention. This innovative CRISPR-empowered SPR platform will further contribute to the fast, sensitive and accurate detection of target nucleic acid sequences with single-base mutations.