90 research outputs found
A Comparative Study of Real Estate Tax in a Mass Appraisal Methods:Empirical Analysis Based on Multiple Regression and Particle Swarm Optimization
随着我国房产税改革的推进,房产税计税基础的评估要求也在不断提高,目前税基评估的核心方法是基于自动评估(AVM)模型的批量评估方法,随着估计模型的复杂化,评估对所需房产特征数据的要求越来越苛刻,而我国房产数据库尚处于建立的初级阶段,基础数据不充分,限制了模型的应用。 本文首先论述了我国房产税税基评估工作的现状及税基批量评估技术的应用前景,针对目前评估中出现的问题提出在其他领域小样本研究中应用广泛的粒子群优化(WCPSO)算法来对小范围房产进行评估,该算法的实现依托于计算机的智能寻优过程,将其得到的房产估价与传统多元回归(MRA)方法进行比较分析,将有利于模型评估精度的提高与经济解释性的改善。 ...As China's real estate tax reform, the requirements of tax base assessment of property tax are also rising. At present, the core method of tax base evaluation is the mass appraisal method based on automated valuation (AVM) model. With the complexity of estimation model, the requirement of the real property data is becoming more and more demanding. However, China's real estate database is still in ...学位:资产评估硕士院系专业:经济学院_资产评估硕士学号:1552014115190
A Different Kind of Suburbanization: Los Angeles Working-Class Suburbs,1920—1940
美国郊区史研究的主流观点认为,中产阶级白人是郊区最早的居民,也是数量上占绝对优势的群体,甚至郊区就是中产阶级白人居住区的同义语。这种观点不仅在美国,而且在我国学术界也有很大影响。然而,根据近年的研究,许多大都市区也有数量可观的工人郊区,这一点洛杉矶最为典型。1920—1940年间,工人郊区曾是这里最主要的郊区模式,工人是此时洛杉矶郊区化的主要参与者,其动力是郊区的工业化进程、廉价住房市场和交通技术的进步。通过对人口统计数据中居民的职业、受教育情况、族裔、住房等信息的分析,可以揭示这种异于传统的郊区化模式。研究此前被认为不存在或被忽略的工人郊区的历史,有助于更全面地理解郊区化进程,丰富对大都市区发展历史的认识,也部分说明了环境不公正形成的历史原因。The mainstream view of American suburban history is that middle- class whites were the earliest residents of suburban,they also were overwhelmingly in number. In this opinion,middle- class whites were the synonym of suburban. This opinion was widely accepted in both American and China. However,many metropolitans had considerable working- class suburban,of which Los Angeles is a poster child. Driven by industrialization and low- price house market of suburban,working-class suburban used to be the mainstream suburban models between 1920 and 1940. By analyzing the census' residents' career and houses,this thesis tried to uncover this new kind of suburban models,which can help us get more complete comprehension to suburbanization,also enrich understanding to metropolitan history
On the Reasons of U.S.Small Business’Development In 1980s
在20世纪80年代美国的重新崛起中,小企业在提供就业岗位和促进技术创新两方面扮演了重要角色。追溯历史我们发现,在战后到20世纪70年代末的这段时间里,小企业一直默默无为。为什么会在80年代爆发出如此大的能量,以至于整个美国经济都受益匪浅。 本文试图从经济、社会文化、政府政策三个方面,对此做出回答。 经济方面,一方面因为通货膨胀的降低改善了经济环境,一方面因为从20世纪80年代开始的有利于小企业发展的经济结构的调整。 政府政策的影响则是一个推动小企业发展的直接因素。20世纪80年代,美国政府颁布了多项法律,这些法律从税收、技术转移、放松管制和资金支持等方面直接促进了小企业的发展。 社会文...Small businesses played a key role in job creation and technology innovation in 1980s,in which period U.S. experienced a distinguished spring up. We noticed that small businesses are nothing important during the period from the Second World War to late 1970s.It’s worth researching the reason why small businesses are so prosperous in 1980s that benefited the whole U.S. economy. The dissertation is...学位:历史学硕士院系专业:人文学院历史学系_世界史学号:1032008115233
中国医务人员医疗标准执行现况及影响因素调查
目的调查我国医务人员医疗标准执行现况及其影响因素,进而了解标准未完全执行的原因。方法采用多阶段分层抽样法,通过实地和网络问卷调查相结合的方式,根据国家统计局地区划分标准,共招募了中国东部、中部、西部和东北4个地区共抽取10375名医务人员填写问卷。结果中国医务人员自我报告的对专业范围内已发布的标准执行率为82.2%。样本医务人员对医疗标准执行率上存在地区(Wald=10.973,P<0.05)、机构级别(Wald=95.052,P<0.01)以及标准认可程度(Wald=689.166,P<0.01)间存在差异。结论中国医务人员对所在专业范围内已经发布的相关标准的自我报告执行程度较高。国家卫健委医疗相关标准调查(2018-65
五配位氧磷烷分子间配体交换反应-RNA水解和融合过程的化学模型(英文)
具有五元环和三配体结构的五配位氧磷烷(ab2)在碱催化条件下自发进行分子间的配体交换反应,产生不同配体组合的全部三种五配位氧磷烷(a3,b3和a2b)。如果把其中a3与b3作为父代分子,其配体交换产生的五配位氧磷烷a2b和ab2可以视作子代分子,从而自发实现了分子结构的多样化。因此,五配位氧磷烷分子间配体交换反应可以作为研究生命过程中具有五配位磷中间体结构化学性质的模型,对理解基因转录和生命信息储存等过程中涉及的RNA分子剪接、水解和融合等重要生命过程的分子机制提供了重要依据
五配位氧磷烷分子间配体交换反应-RNA水解和融合过程的化学模型(英文)
具有五元环和三配体结构的五配位氧磷烷(ab2)在碱催化条件下自发进行分子间的配体交换反应,产生不同配体组合的全部三种五配位氧磷烷(a3,b3和a2b).如果把其中a3与b3作为父代分子,其配体交换产生的五配位氧磷烷a2b和ab2可以视作子代分子,从而自发实现了分子结构的多样化.因此,五配位氧磷烷分子间配体交换反应可以作为研究生命过程中具有五配位磷中间体结构化学性质的模型,对理解基因转录和生命信息储存等过程中涉及的RNA分子剪接、水解和融合等重要生命过程的分子机制提供了重要依据.Project supported by the National Natural Science Foundation of China(Nos.21778042,41876072,21772163,41576081)the Xiamen Southern Oceanographic Center(No.17GYY002NF02)the Fundamental Research Funds for the Central Universities(No.20720170069)~
TLR4的表达与急性胆道梗阻时内毒素致小鼠肝脏损伤的关系
目的探讨急性胆道梗阻时内毒素损伤小鼠肝脏的机制及其与TLR4表达的关系。方法雄性C57BL/10J(WT)小鼠42只,随机分为生理盐水组(NS组,n=21)、内毒素处理组1(LPS1组,n=21),C57BL/10ScnJ(TLR4-/-)小鼠21只,为内毒素处理组2(LPS2组)。3组均行胆总管结扎术,LPS1、LPS2组小鼠于胆总管内注射LPS(8ng/μL,10ng/g体重),NS组注射同等剂量的生理盐水,术后6、12、24h采集标本,RT-PCR检测肝脏组织TLR4mRNA的表达情况,全自动生化分析仪检测血清ALT、TBIL、DBIL水平,ELISA法检测血清TNF-α、IL-6的水平。病理观察肝脏损伤情况,免疫组织化学染色观察肝脏NF-κB的表达。结果 LPS1组与NS组比较肝脏组织TLR4mRNA在6h时表达已有升高,于24h达高峰,ALT、TBIL各时点均明显升高(P<0.01),TNF-α、IL-6表达亦增高(P<0.01),LPS1病理损伤程度较NS组重,免疫组化显示术后24小时NF-κB在LPS1组可见肝细胞明显的核表达。LPS2组与LPS1组比较各血清学指标均明显下降,病理损伤减轻,24h时肝细胞NF-κB核表达较少。结论在急性胆道梗阻时LPS可以加重肝脏组织损伤和机体炎症反应,可能与TLR4的表达增高及NF-κB的表达有关。阻断LPS-TLR4信号通路可以减轻LPS引起的机体损伤
The Research Progress of Kidney Ischemia-Reperfusion Injury on Mechanism and Its Influencing Factors
Beyond the Chicago School: The Rise of New Suburban History in the US
诞生于20世纪20年代的芝加哥学派城市社会学,对美国城市政策的制定和城市史学的发展产生了巨大影响。在其影响下,联邦住房管理局的购买、维修住房贷款向郊区纯白人居住区倾斜;城市研究则形成了郊区富裕、城市贫困、郊区化主要是白人中产阶级在交通技术进步的带动下来到郊区的叙事模式,并将这一叙事上溯至郊区诞生之初。20世纪90年代以来的新郊区史研究,认为之前的郊区史叙事忽略了第二次世界大战前郊区化中的下层群体及与之相关的工业分散、郊区下层住房市场、工人在郊区的生活及政治诉求等方面,同心圆理论不能准确反映芝加哥自身的历史。城市史和芝加哥学派城市社会学的关系经历了深受其影响到与之渐行渐远、再到彻底反思的过程。Appearing in the 1920 s,the Chicago School in urban sociology has impacted American urban policy as well as the writing of urban history. For instance,the School's Concentric Zone Theory influenced the FHA's urban policy,which tended to favor the establishment of homogenous white middle class community in thesuburbs. Urban historians also constructed the narrative on suburbanization,explaining that the urban impoverishment was resulted from the advancement in modern transportation,enabling the white middle class to exit from the cities and relocate to the suburbs. Yet from the 1990 s,new studies in urban history challenged the previous suburbanization narrative,especially the Concentric Zone Theory,for it neglected many aspects related to early suburbanization before World War II,such as the formation of lower social groups,the sprawling of industrial development,the situation of housing market,the life of the working class and their political demands. New urban history also believes that the Concentric Zone Theory has wrongly portrayed the history of Chicago. In a word,having reflected critically on its impact,it seems that the new studies in urban history have come out of the shadow of the Chicago School
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