Convergent genomic signatures of high-altitude adaptation among domestic mammals

Abundant and diverse domestic mammals living on the Tibetan Plateau provide useful materials for investigating adaptive evolution and genetic convergence. Here, we used 327 genomes from horses, sheep, goats, cattle, pigs and dogs living at both high and low altitudes, including 73 genomes generated for this study, to disentangle the genetic mechanisms underlying local adaptation of domestic mammals. Although molecular convergence is comparatively rare at the DNA sequence level, we found convergent signature of positive selection at the gene level, particularly the EPAS1 gene in these Tibetan domestic mammals. We also reported a potential function in response to hypoxia for the gene C10orf67, which underwent positive selection in three of the domestic mammals. Our data provide an insight into adaptive evolution of high-altitude domestic mammals, and should facilitate the search for additional novel genes involved in the hypoxia response pathway.     

Large-scale multiferroic complex oxide epitaxy with magnetically switched polarization enabled by solution processing

Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi_(1-y)/2Fe_yMg_(1-y)/2O₃–(x)CaTiO₃ (BTFM–CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 μ_B/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7–3.0 × 10⁻⁷ s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM–CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications.     

基于FPGA的DDS实现的几种方式

直接数字频率合成器(DDS)采用的是一种新的频率合成技术,它具有频率分辨率高、频率转换快、相位噪声小等一系列优点。本文根据DDS的基本原理,提出了基于FPGA的DDS设计与实现。利用Quartus II、MATLAB/Simulink、DSP Builder等功能强大的开发工具,分别从不同的角度给出了几种基于FPGA的DDS的实现方式。最后,就这几种实现DDS的方式,对其优缺点进行讨论。     

偏远地区高校学生大学英语自主学习能力培养探究

大学英语自主学习是大学生英语学习的一种很有效的学习方式,而自主学习能力的培养是大学英语教学的培养目标之一,它对缓解大学英语教学的诸多矛盾起到重要作用。以自主学习理论为指导,立足偏远地区高校的实际情况,探究偏远地区高校学生大学英语自主学习能力培养的可行性,对提高该类高校学生大学英语学习成绩将起到促进作用。     

财政补贴分配方式变革能促进企业创新吗?

本文基于全国税收调查数据,将财政专项资金竞争性分配改革作为准自然实验,使用双重差分法考察竞争性财政补贴分配方式对企业创新的影响。研究结果表明：相比于传统的财政补贴分配方式,竞争性财政补贴分配方式能够更好地激励企业创新,并且这种激励作用具有持久性。竞争性财政补贴分配方式通过“挑选效应”和“认证效应”两种机制激励企业创新。进一步分析表明：以GDP为主的绩效考核压力会削弱竞争性财政补贴分配方式的创新激励作用,市场化水平提高能够增强竞争性财政补贴分配方式的创新激励作用,财政专项资金竞争性分配改革对中小企业创新激励作用更为明显。     

企盼高校招生的更多自主权

2006年注定是一个里程碑式的教育大年。在中华人民共和国的教育史上,高校自主招生的“破冰之旅”,首次在上海交通大学和复旦大学起步。目前尘埃落定,格局初成,两校所认定的近600名考生,除非此后在常规高考中遭遇意外落马而大失水准的尴尬,以致会导致被重新估量的可能,一般情形下都会成为高教改革的首批受益者,共和国教育史上的第一代破冰冲浪的“宠儿”。     

对盐类水解反应规律的再思考

水解反应规律:有弱才水解,无弱不水解,弱弱双水解,谁强显谁性,都弱具体定.其中"弱弱双水解"是指弱酸根离子与弱碱根离子的水解相互促进,发生双水解反应,那么弱酸根离子与弱碱根离子相遇是否一定发生双水解反应呢?     

从中国传统文化看休闲

本文从中国传统文化出发,对“休闲”内涵给出了具有人类学意义的定义,论证了休闲人与自身以及与自然和谐的内在机制。     

一种最优无线电信道分配方案

在信道复用距离为常数,相邻的基站信道相差的条件下,研究了蜂窝状通信系统的最优信道分配问题。给出了此信道分配问题的数学模型,并论证了该模型求出的是最优解,并深入阐述了通信系统的信道分配问题。