3,636 research outputs found
Characterization of long-term natural outcome of chronic hepatitis B virus infections
慢性乙型肝炎病毒感染是世界重要的公共卫生问题,可以导致肝癌、肝硬化等终末期肝病,继而导致死亡。我国是慢乙肝高流行区,全国约有1.2亿的慢性HBV携带者,慢性乙肝患者约3000万例,HBV感染对我国国民健康造成严重威胁。本研究的主要目的在于研究自然人群慢乙肝感染者的长期转归及其相关因素,监测乙肝相关肝硬化和肝癌的发病率,并且研究成人接种乙肝疫苗对其新感染的保护以及终末期肝病发生的影响。有助于更加深入的了解和认识乙肝,并为预防和预测乙肝相关终末期肝病提供重要的数据和依据。 本研究利用本实验室前期研发的戊型肝炎疫苗的三期临床试验,在江苏省东台市建立了一个自然人群的随访监测研究队列。其中我们对446...Chronic HBV infection is a major public health problem in the world which can lead to liver cancer, cirrhosis, end-stage liver diseases, and death in the end. China is a HBV high prevalence area with about 120 million chronic HBV carriers and 30 million cases of chronic hepatitis B patients. HBV infection is a serious threat to our public health. The main purpose of this study is to investigate th...学位:医学硕士院系专业:公共卫生学院_流行病与卫生统计学学号:3272013115055
Design and Implementation of Smartphone Bus Information Query System Based on Android Platform
随着我国城市化经济的飞速发展,公共交通在这一进程中的作用越来越重要。目前, 我国城市公共交通的线路和站点越来越多,逐渐形成了一个复杂的公共交通网络。然而, 正是因为公交网络的复杂,导致人们无法快速选择合适的公交线路。因此需要一个公交查 询系统来帮助公交乘客快速选择适合出行需求的路线,以节约时间及费用成本。目前虽然 已经存在一些公交信息查询系统,但大多数需要通过电脑网页来查询,用户体验方面还不 是特别优秀。国内手机普及率几乎达到100%,因此开发出一款基于智能手机的公交信息查 询系统,对公交乘客来说可用度非常高。 论文调研了目前手机应用程序和公交信息查询的系统,发现这些公交信息查询...With the rapid development of urbanization in China, the role of public transport in this process is becoming more and more important. At present, the number of city public transportation lines and the stations is growing rapidly, and is gradually becoming a complex public transport network. However, precisely because of the complexity of the public transport network, people can not choose the...学位:工程硕士院系专业:软件学院_工程硕士(软件工程)学号:X201323174
Goal Interdependence for Promoting Firm Innovation and New Product Development Performance: The Mediating and Moderating Effects
近年来,随着中国经济新常态的逐步推进,大众创业、万众创新成为促进中国经济新增长的“双引擎”之一。技术和产品生命周期的进一步缩短,成为企业面临的外部环境新特征。在这样的环境中,企业能否稳固市场地位并实现可持续发展,主要取决于企业对技术和市场动荡进一步加剧的外部环境的适应能力。而应对环境变化带来的挑战的重要途径,就是积极开展技术创新,使企业在研发、生产和营销等方面具备整合性的优势能力,从而比竞争对手更高效持续地开发出满足市场需求的新产品,取得企业绩效。为达到这个目的,企业单纯依靠自身资源,显然无法满足发展需要,它必须朝着更高效、更开放、更合作的方向发展。 上下游企业之间频繁的资源交换,使得供应链...Along with the development of the ‘new normal’ of China’s economy, encouraging people to do business creatively and driving innovation became one of the ‘double engines’ for promoting economy growth. More than ever before, this encouragement inevitably furthers the shortening of technology life cycle and product life cycle. Under such a circumstance, coping with technological turbulence and market...学位:管理学博士院系专业:管理学院_企业管理学号:1762013015375
Giant Raman Enhancement on nanoporous Gold Film By Conjugating with nanoparticles for Single-molecule Detection
Hot spots have the contradictively geometrical requirements for both the narrowest interstices to provide strong near-field coupling, and sufficient space to allow entrance of the analytes. Herein, a two-step method is employed to create hot spots within hybrid nanostructures, which consist of self-supported nanoporous gold films with the absorbed probes and subsequent nanoparticle conjugates without surface agents or mechanical motion. The molecules confined into 1 nm interstice exhibit 2.9 × 107 times enhancement in Raman scattering compared to pure nanoporous gold. Giant enhancement primarily results from strong near-field coupling between nanopore and nanoparticle, which is theoretically confirmed by finite-difference time-domain simulation. Excellent detection limits toward 10−11 mol l−1 offer an opportunity to track spatial orientation of single molecule and engineer hybrid nanostructures as commercial SERS substrates
Identifying DNA-binding Proteins Based on Feature Construction and Feature Selection
DNA结合蛋白在分子生物学中扮演重要角色,其影响基因表达调控、DNA复制等活动。然而以生物实验的方式识别DNA结合蛋白,耗时且昂贵。数据分析的方式已成为识别DNA结合蛋白的重要途径。为提高DNA结合蛋白的识别性能,针对蛋白质序列数据特点,研究DNA结合蛋白识别问题中的特征工程,包括特征构造与特征选择。该特征工程能有效提高DNA结合蛋白的识别性能,为识别DNA结合蛋白提供了一种简便、高效的方法。论文主要包括以下几个方面。 1)特征构造:针对DNA结合蛋白序列之间低相似性、独立性、序列长度不同等特点,本文从物理化学特性、混沌游戏表示、分形维数、位置特异性得分矩阵和频谱分析五种不同角度的特征构造方...DNA-binding proteins play a vital important role in molecular biology, it has an impact on genes regulation, DNA replication and so on. However, DNA-binding proteins identified by experimental techniques, which are time-consuming and expensive.The method of data analysis has been becoming animportant way to identify DNA-binding proteins.In order to improving the identificationperformance, the feat...学位:工学硕士院系专业:航空航天学院_工程硕士(控制工程)学号:2322014115336
不同脂肪源对异育银鲫的生长、体组成和肌肉脂肪酸的影响
配制了十种等氮等能的饲料饲喂3.53 g的异育银鲫幼鱼12周,探讨异育银鲫对不同脂肪源的利用效果。十种饲料中分别添加8%的鱼油(FO)、椰子油(CNO)、玉米油(CO)、亚麻油(LO)、大豆油(SO)、菜籽油(RO)、1∶1鱼油-椰子油(FCNO)、1∶1鱼油-玉米油(FCO)、1∶1鱼油-亚麻油(FLO)和1∶1∶1∶1鱼油-椰子油-玉米油-亚麻油混合油(MIX)。每组饲料三个平行,每个平行30尾。实验在循环水养殖系统中进行,水温控制在(24±1)℃。结果表明,在单一脂肪源中,豆油组和椰子油组的增重率最高,其次是菜籽油组,鱼油、玉米油和亚麻油组的增重率最低。与相应的单一脂肪源相比,饲料中鱼油与椰子油、玉米油或亚麻油1∶1混合后使用提高了异育银鲫的生长。摄食不同脂肪源饲料的异育银鲫血清生化指标、各组织的水分和脂肪含量差异不明显(P>0.05)。肌肉脂肪酸与饲料脂肪源呈明显正相关。摄食豆油和菜籽油饲料的鱼体肌肉中20:4n-6较高,而摄食亚麻油饲料的鱼则含有较高的20:5n-3和22:6n-3,表明异育银鲫具有转化18:2n-6和18:3n-3为高不饱和脂肪酸的能力。从实验可以看出,豆油、椰子油和菜籽油是异育银鲫饲料中良好的脂肪源
Qtech-413 粘弹阻尼材料在盾构隧道中减振性能研究
根据盾构隧道的结构特点,用Qtech-413 粘弹阻尼材料对盾构管片标准块进行约束阻尼处理,通过单点锤击振动实验,得到处理前后结构的时域波形、固有频率、复合损耗因子等振动特性。实验结果显示:经过约束阻尼处理后,盾构管片振动加速度幅值降低了26.7%,振动时长降低了50%;各阶固有频率均有所降低,且随着频率的增加,降幅逐渐增加;各阶复合损耗因子均有所升高,高频增幅比低频增幅更大;振动总级值降低了10 dB 左右。因此,Qtech-413 粘弹阻尼材料应用于盾构隧道能降低振动加速度幅值、振动时间、固有频率和振动总级值,增加复合损耗因子,对高阶固有频率和复合损耗因子影响较大,低阶影响较小
Diagnosis and Treatment of Strategy Execution in Company E on Balance Score Card Perspective
笔者选取所任职的这家典型的通信网络服务企业,将企业在战略执行过程中遇到的问题罗列出来,并分析了问题形成的原因,最后着力针对案例公司在战略执行过程中遇到的问题提出了基于平衡计分卡视角的解决办法:第一,启动由高层管理团队参与并主导的战略沟通;第二,成立若干指标开发小组着手建立平衡计分卡系统,实现由战略向部门绩效、个人绩效的转化;第三,成立专门小组主导战略执行循环过程为和勤公司保持竞争优势、保证公司战略得以实现提供可供借鉴的改善对策,并客观的估计了战略执行初期所面临的潜在挑战及应对策略:例如企业的资源分配应全力支持战略执行的各项行动、各部门之间的协同力将成为战略执行过程中的有力保障、战略实施情况及成...Writer inauguration of the correspondence network profession belonged to by business enterprise is Chinese new century of newly arisen with support lord industry, carry out aspect to face a huge challenge in the strategy, correspond by letter external industry environment of network profession sharply worsen, add of our country correspondence network profession oneself of risk control consciousnes...学位:管理学硕士院系专业:管理学院_工商管理硕士(高级管理人员工商管理硕士)学号:X201115607
Bayesian Inference for Nonlinear DSGE Model via Multiple-try Metropolis Algorithm
本文提出一种改进的多重尝试Metropolis算法,用于非线性动态随机一般均衡模型的贝叶斯参数估计和模型选择。多重尝试策略通过每次迭代抽取多个尝试点的方法来提高算法的混合速率,新方法中提出使用近似的方法提高计算速度,并通过接收概率调整偏差。数值实验表明新方法在相同的计算时间内具有更高的估计效率。最后,本文比较了具有不同货币政策设定的模型对中国经济数据的拟合效果,发现中国数据更加支持具有时变通胀目标的模型。This paper proposes a multiple-try-based Metropolis algorithm for Bayesian parameter estimation and model selection in nonlinear dynamic stochastic general equilibrium( DSGE) models. Multiple-try method generates multiple trial points in each iteration to achieve faster mixing rate. The new approach proposes to use approximation to save computational cost,the approximation bias is adjusted through the acceptance rate. Simulation results demonstrate effectiveness of the proposed algorithm. The algorithm is applied to estimate DSGE models with different monetary policy settings using the macroeconomic data of China. It shows that the data favors the model with time-varying inflation target.国家自然科学基金项目“状态空间模型参数的高效序贯蒙特卡洛估计及在金融中的应用”(11101341)的资
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