Crossbreeding parameters for fertility traits in a rotational crossbreeding between Landrace and Piétrain pigs

The reproduction characteristics of 343 sows in six different breeding groups were analyzed to estimate the crossbreeding parameters. The results indicated that the ovulation rate and the weights of uterus and ovary are mainly determined by the additive genetic effects while the nonadditive genetic effects play an important role in embryonal traits and litter performance. The heterosis effects in the first litter are larger than those in the second litter because of heterosis x environment interaction. The results also showed the existence of a highly significant maternal heterosis effect on the fertility traits of sows.     

Boundary control of a linear distributed parameter bioprocess

This paper is concerned with boundary control of a linear distributed parameter bioprocess. Huang's result (Ann. Differential Equations 1(1) (1985) 43) on the spectrum determined growth assumption is applied to prove that the closed-loop system becomes exponentially stable under a certain condition with respect to the feedback gain. Moreover, it is shown that the decay rate of the open-loop system is given by letting the feedback gain tend to zero.     

文献老化研究现状的分析

随着科学技术的不断进步 ,科学知识不断更新 ,新的知识不断取代旧的知识 ,这是科学发展的客观规律。而作为科学知识记录的科技文献必然要随之发生新陈代谢。文献老化是一种必然的普遍社会现象。文献老化及其规律是科学计量学与文献计量学的重要课题。自从C .F .Gosnell研究文献老化现象以来 ,人们围绕文献老化的机理、量度指标、数学模型及其影响因素展开了大量研究。研究主要是围绕三个方面进行的 :一是文献老化理论的研究 ,进而探索文献信息传播的动态规律 ;二是对研究方法与定量描述方法的研究 ,以便准确把握老化规律及其动力机制 ;三…     

量化数字人文综述

数字人文对多样化研究内容、语言和学者的包容性,使其在近20年得到突飞猛进的壮大,并逐渐涉及人文学、社会学、计算机科学等多个领域。然而,包容的“大帐篷”不仅在一定程度上限制了对数字人文具体学科内容、科研范畴、学者群体和学科历史的理解,也使得学科成长和拓展缺少客观数据和理论的支持,从而无法健康且可持续地发展。文章回顾前人对数字人文所做的学科研究,重点集中在使用计量和统计等方法来揭示数字人文的知识结构、内容演变、合作模式和学者背景等工作上,以期帮助学界从量化的角度认识数字人文的形成、发展和前景。     

Deep Participation in Underserved Communities: A Quantitative Analysis of Hearken’s Model for Engagement Journalism

ABSTRACT

Hearken is a proprietary news engagement platform growing in popularity. Under the Hearken approach, audience members are invited to participate in the newsmaking process. Hearken strives to assist news organizations in providing local and hyperlocal content that meets audience needs and demands while preserving elements of the journalist’s role as gatekeeper. Hearken has also worked to help news organizations reach underrepresented populations with mixed results per its own anecdotal analyses. This study employs a quantitative content analysis comparing one year’s worth of coverage at four different local NPR affiliates in the United States to provide a breakdown of Hearken content versus traditional reporter-driven content in the following four categories: emphasis on hyperlocal coverage, story topic prevalence within local and hyperlocal coverage, emphasis on coverage of underrepresented communities, and story topic prevalence within coverage of underrepresented communities. Findings reveal listener-driven Hearken content favors hyperlocal news on lifestyle issues while reporter-driven stories emphasize state-level governance and politics as well as local crime. These indicate a stark contrast between the content audiences want and that which journalists tend to report. The nuanced normative implications, possibilities and limitations of Hearken’s model of “deep participation” are addressed in some detail.     

碱胁迫对叶片延迟发光的实验研究

选用绿宝石喜林芧叶片为材料,用BPCL型微弱发光测量仪测量了叶片经高浓度NaOH溶液处理后的延迟发光情况。结果发现:同一个叶片随着处理时间的延长,其延迟发光最初值和最后100s的光子数都先有一个小幅度的上升,然后又迅速下降;不同的叶片在相同的处理时间下,随着NaOH质量分数的增加,延迟发光最初值和最后100s的光子数都呈现上升的趋势,NaOH质量分数越大,上升得越快,随着处理时间的延长,上升的趋势变得越来越缓,最后各曲线越来越接近,且趋于平稳。整个实验表明,延迟发光可以规律性地反应碱胁迫对叶片的伤害程度,这为生物物理方法测量外界胁迫对叶片的影响提供了参考。     

缪斯殿外 别有新天——王兆鹏先生的学科交叉跨界研究管窥

王兆鹏教授之治学,既拥唐门考据之长,注重文献学硬功夫,故能成其深,又不囿于学科限制,注重学科交叉新思考,故能成其大。他在文献考据、理论阐释方面皆颇有建树,备受瞩目。王兆鹏在理论阐释研究中的学科交叉、文学跨界研究是其治学之特色,其定量分析、传播接受、范式批评等研究成就尤其突出。     

半实物仿真的炉温智能控制系统设计

结合模糊控制与OPC技术,将电炉实物接入仿真计算机.利用Matlab建立一个二维模糊控制器,温差和炉温变化率为输入量,变压器电压为输出量;根据实际经验分析电炉的加热过程,制定控制规则表,写入控制规则,完成控制器;在Simulink中设计并完成半实物仿真控制图,即设计一个智能控制炉内温度的系统.对不同量化因子k1和k2、比例因子k3进行仿真,比较电炉温度曲线图,分析出较合理的因子参数,实现了对电炉炉温的有效控制.系统可节省大量的调试时间,又能获得较准确的仿真效果.     

TiO2粉末多晶X射线衍射Rietveld全谱拟合定量相分析

采用Rietveld全谱拟合的方法对TiO2粉末中锐钛矿和金红石进行定量分析,通过标准样品数据和计算结果进行比较,对该方法的准确性、重复性以及普适性分析,计算结果与标准样品数据符合良好.该方法具有快速准确、成本低、可重复的特点,在高纯度矿物产品工业中将具有广阔的应用前景.     

数字集成电路参数测试仪的设计

针对现有集成电路测试设备结构复杂,功能单一的缺点,本文利用FPGA核心板、D／A模块、A／D模块、电流转换电压电路等器件,采用SOPC技术,设计了一个中小规模通用数字集成电路测试系统,在逻辑功能测试的基础上。实现了74系列中小规模数字集成电路直流性能参数的测试。通过实验,将测试结果与标准的反相器参数进行比较,数据结果一致。表明参数测试仪符合设计要求,设计方案具有一定的参考价值。