Mutagenecity in the mal regions ofEscherichia coli

Résumé L'efficacité de la nitrosoguanidine (MNG) dans différents milieux de culture et tampons a été étudiée. Les résultats obtenus montrent qu'avec le temps, la fraction de cellules survivant au traitement diminue progressivement alors que la fréquence de mutation augmente dans tous les milieux. L'activité de cet agent atteint un maximum dans le milieu DM-glucose tandis que dans le tampon TM elle est à son plus bas niveau.     

最小学习机

针对极端学习机(ELM)不能用于多层前向神经网络学习的问题,通过揭示单层前向神经网络(SLFN)的ELM与岭回归以及中心化的岭回归之间的关系,提出了SLFN的最小学习机.通过证明核化的中心化岭回归与核化的PCA之间的关系.提出以无限可微的核函数为激励函数的多层前向神经网络(MLFN)的最小学习机LLM.SLFN/MLFN的最小学习机能够保持ELM的上述优势.     

Quantum computational advantage via 60-qubit 24-cycle random circuit sampling

To ensure a long-term quantum computational advantage,the quantum hardware should be upgraded to withstand the competition of continuously improved classical al...     

Key factors for efficiently implementing customized e-learning system in the service industry

In recent years,e-learning system has been adopted as a training tool in many firms,as it can help employees to complete training in a short time and at a low cost.Within this context,since 2003 the Industrial Development Bureau(IDB) of the Ministry of Economic Affairs(MOEA) in Taiwan sponsored more than 50 enterprises each year to help them implement customized e-learning systems. Past research on e-learning mostly focused on one criterion and adopted regression approach,such as examining the relationsh...     

可扩充计算年度综述

本书是《可扩充计算》丛书的第5卷。全书是由4篇综述组成的。第1篇不规则算法的并行计算策略，考虑了三个具有代表性的不规则应用；无结构重啮合、稀疏矩阵计算和N体问题。第2篇在群与网格上的大规模不规则计算的实时支持，介绍了一个正在形成的计算基础结构——在计算群集和计算网格上实施不规则数据密集应用的一种综合方法，即想法、技术、概念及软件结构；提出了并行化策略和一个叫做lib的运行时程序库，该程序库支持不规则与缺乏核心的计算，并且介绍了在安装有建立于lib基础上的软件的PC以及工作站群集所获得的试验执行结果。     

Creation and diagnosis of a solid-density plasma with an X-ray free-electron laser

Matter with a high energy density (>10(5)?joules per cm(3)) is prevalent throughout the Universe, being present in all types of stars and towards the centre of the giant planets; it is also relevant for inertial confinement fusion. Its thermodynamic and transport properties are challenging to measure, requiring the creation of sufficiently long-lived samples at homogeneous temperatures and densities. With the advent of the Linac Coherent Light Source (LCLS) X-ray laser, high-intensity radiation (>10(17)?watts per cm(2), previously the domain of optical lasers) can be produced at X-ray wavelengths. The interaction of single atoms with such intense X-rays has recently been investigated. An understanding of the contrasting case of intense X-ray interaction with dense systems is important from a fundamental viewpoint and for applications. Here we report the experimental creation of a solid-density plasma at temperatures in excess of 10(6) kelvin on inertial-confinement timescales using an X-ray free-electron laser. We discuss the pertinent physics of the intense X-ray-matter interactions, and illustrate the importance of electron-ion collisions. Detailed simulations of the interaction process conducted with a radiative-collisional code show good qualitative agreement with the experimental results. We obtain insights into the evolution of the charge state distribution of the system, the electron density and temperature, and the timescales of collisional processes. Our results should inform future high-intensity X-ray experiments involving dense samples, such as X-ray diffractive imaging of biological systems, material science investigations, and the study of matter in extreme conditions.     

遍历测度的一个定理及其应用

设f是紧度量空间上的连续自映射。本文证明,如果f的所有非渐近周期的非游荡点的集合的基数是可列的,则f的遍历测度是它的周期轨道原子测度,且f的拓扑熵为零。作为推论还得到,逐点周期映射有零拓扑熵。另外,当f没有周期点时,其非游荡点的集合的基数是不可列的。     

Function and regulation of Dyrk1A: towards understanding Down syndrome

Down syndrome (DS) is associated with a variety of symptoms, such as incapacitating mental retardation and neurodegeneration (i.e., Alzheimer’s disease), that prevent patients from leading fully independent lives. These phenotypes are a direct consequence of the overexpression of chromosome 21 genes, which are present in duplicate due to non-disjunction of chromosome 21. Accumulating data suggest that the chromosome 21 gene product, dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A (Dyrk1A), participates in the pathogenic mechanisms underlying the mental and other physical symptoms of DS. In this review, we summarize the evidence supporting a role for Dyrk1A in DS, especially DS pathogenesis. Recently, several natural and synthetic compounds have been identified as Dyrk1A inhibitors. Understanding the function and regulation of Dyrk1A may lead to the development of novel therapeutic agents aimed at treating DS.