Agglomeration of Services in American Metropolitan Areas

The growth of many service industries among American metropolitan areas stem from an eclectic set of forces. These include market penetration effects of increasing importance of services throughout the economy, agglomeration effects in immature and deregulated industries, and institutional and infrastructure constraints. These diverse forces are interpreted as urbanization and localization economies. A cycle of centralization of 27 fast growing service industries is documented for MS As in the period 1977-84. The two agglomeration effects are tested directly, using a power function model that relates employment and establishment growth to MSA size and initial level of employment in a local industry. Localization economies rather than the general advantages of metropolitan size best explain the growth patterns. This result implies that service industrial complexes are rapidly emerging in American metropolitan areas.     

A Territorial Articulation Index for Rural Areas Applied to Four Spanish Comarcas

This paper proposes a model for calculating a composite index to evaluate the internal territorial cohesion or articulation of rural areas, specifically rural Spanish comarcas (groups of municipalities with common geographic and historical characteristics). Evaluation is based on the optimum spatial distributions of their urban nuclei and access to roads by their inhabitants. First, we built the index for spatial distributions of urban nuclei in each comarca. Next, we constructed road accessibility indexes for all urban nuclei to each other and to the main urban nucleus (defined by the largest concentration of services). Based on these indexes, we developed an Internal Territorial Articulation Index (ITAI) that reflects the spatial distribution of the territory's urban nuclei in terms of their aggregation, internal accessibility within the comarca, and relationship with the main urban nucleus. The ITAI was applied to four Spanish comarcas in the province of Almería: Almería Alpujarra, Almanzora, Los Vélez, and Almería Poniente. The results are highly varied and allow areas with low degrees of territorial articulation or coherence to be identified either by the distribution of their urban nuclei or by their poor accessibility to roads. Results were unfavourable in mountainous regions with steep slopes and in areas furthest from the province's large urban nuclei. The conclusions may help develop settlement and road transport infrastructure strategies in these rural comarcas.     

Diverse Retail Structure and Christaller's Separation Principle in Medium-Sized Metropolitan Areas

Standardized features dominate the retail landscape of the United States and are the physical components of retail districts. This study tests the hypothesis that standardized building blocks have failed to produce the same retail structure in all metropolitan statistical areas (MSAs). Ninety-two medium-sized MS As are analyzed to determine if the arrangement and strength of their retail districts differ. The relationship between functional and spatial aspects of retail structure in central place theory provides a basis for testing the hypothesis of diversity. Christaller's separation principle provides a plausible conceptual framework for diverse retail structure if each MSA is analyzed as an isolated region. Five types of retail structure are analyzed using data obtained from the Census of Population and the Census of Retail Trade. The types are identified by performing a serial iterative partition cluster procedure on prioritized metropolitan sales variables. The statistical significance of the types is tested with Mann-Whitney U-tests of functional variables not used in the cluster analysis. Verification confirms five distinctive types. Monocentric and polycentric retail structures exist but decentralized retail structure is even more common in medium-sized MSAs. The distribution of types of retail structure follows regional pattern that indicate historical and political factors as contributing causes.     

Multi -factor Design Pattern for Parking Index of Residential Areas

According to the motor vehicles development in modern cities,this article explains the principles of establishing a parking index for residential areas and puts forward how to establish a set of new parking index to be adapted to the developing situation,meanwhile,the implement of multi-factor design pattern is discussed.     

Growth of Creative Occupations in U.S. Metropolitan Areas: A Shift‐Share Analysis

ABSTRACT This article uses a shift‐share model to investigate the growth of creative occupations in U.S. metropolitan areas during the 1990s. Empirical findings indicate that the performance of the creative economy varied widely across the U.S., and that the highest competitive growth rates of the creative workforce occurred in the Rocky Mountain, Southeast, and Southwest regions. Further analysis focused on whether high competitive workforce growth between 1990 and 2000 translated into high competitive employment growth from 1999 to 2003. The results show that many of the areas with the highest competitive growth rates of creative economy employment from 1999 to 2003 were some of the weakest regions in terms of creative workforce growth during the 1990s. This raises questions about the extent to which jobs follow people in the creative economy, and suggests that an initial strong presence in the creative economy is not a prerequisite for future growth.     

Urban Polycentricity and the Costs of Commuting: Evidence from Italian Metropolitan Areas

Polycentricity at the metropolitan scale is perhaps the model of spatial organisation that needs to be investigated more thoroughly as regards its effects on travel. The aim of this paper is to test the role of polycentricity—as well as other spatial characteristics, such as compactness, functional diversification and size—in the costs of commuting, taking into account an external cost component (per‐capita CO₂ emissions) and a private cost component (time spent on travelling). The degree of urban polycentricity has been measured by adopting a dynamic approach based on commuting flows and on social network analysis tools. The analysis is carried out using a database of 82 Italian metropolitan areas (MAs). Results show that MAs with a higher degree of polycentricity are more virtuous both in terms of private and external costs of mobility, while the degree of compactness is associated with lower environmental costs but with higher private costs. Size is associated with both higher external and private costs, while the role of functional diversification turns out to be statistically insignificant. Socio‐demographics also play a role.     

Comparative Analysis of the Total Factor Productivity of Manufacturing in Northeast Asian Metropolitan Areas

We compare and analyze the total factor productivity of the manufacturing industries in the major metropolitan areas of South Korea, China, and Japan. This study can contribute to the economic cooperation among these countries by analyzing their productivity growth and evaluating their relative competitiveness. Statistical data from manufacturing industries are used to analyze five metropolitan areas. The manufacturing industries are classified into 10 sectors, and two different time periods (before and after 1997, when the foreign currency crisis began in Korea) are examined. The results in terms of the development and competitiveness of the manufacturing industries in Korea, China, and Japan will be useful in establishing promotional strategies.     

Why Is U.S. Poverty Higher in Nonmetropolitan than in Metropolitan Areas?

ABSTRACT In the U.S., people are more likely to be poor if they live in a nonmetropolitan (nonmetro) than in a metropolitan (metro) area. A common explanation for this phenomenon is that nonmetro places offer relatively few economic and social opportunities. This article explores another plausible explanation, asking if the disproportionate poverty in nonmetro areas partly reflects attitudes of people with personal attributes related to poverty: they may be attracted to nonmetro places or otherwise reluctant (or unable) to leave them. To test this hypothesis, data from nine waves of the Panel Study of Income Dynamics (PSID) are used to track economic well‐being and nonmetro–metro residential choice among a sample of 2,007 low‐income householders. A series of multivariate regression models are estimated in which the dependent variable is a householder's income to need (adjusted for spatial cost‐of‐housing differences), and regressors are individual attributes, a binary variable for nonmetro residence, and state fixed‐effects. Regression results show that controlling for householder educational attainment reduces the negative association between nonmetro residence and income to need; but controlling for unobserved, time‐invariant heterogeneity via individual fixed‐effects increases the magnitude of this negative association. Study findings thus appear to indicate that enduring nonmetro poverty is explained both by a sorting of low human capital individuals into nonmetro areas and by reduced economic opportunities in nonmetro compared to metro places.     

多元统计分析在三明烟区土壤肥力评价中的运用

以福建三明烟区11个县(市)的17个土壤肥力因子为例,采用多元统计的主成分分析法对土壤肥力等级进行综合地评价,为烟区科学合理的施肥提供依据。借助SPSS统计软件,可以得出土壤肥力因子前4个主成分的特征值λ>1,且方差贡献率分别为46.528%,20.422%,10.631%,8.164%,累计贡献率为85.745%,已足够反映原指标信息。这4个主成分分别概括为(1)土壤P、土壤交换性Ca以及土壤微量元素因子;(2)土壤粘粒和土壤Mg素因子;(3)土壤有机质因子;(4)土壤酸碱度因子。再借助SPSS统计软件得出方差极大旋转后主成分因子得分,最后再计算主成分因子的综合得分。结果显示:大田县土壤肥力等级排名第一,其土壤综合肥力水平最高。     

作物抗旱指数的概念和统计方法

田间测定农作物抗旱性所使用的胁迫敏感指数(1-Yd/Yp)/(1-∑Yd/∑Yp)是所谓抗旱系数Yd/Yp的变型,二者相关系数r=-1.因此,前者并没有改进后者的缺陷.作者以30个冬小麦为材料,经过两年试验,提出了作物抗旱指数的概念,其表达式:品种旱地产量×抗旱系数/供试品种旱地平均产量,使抗旱生理指标的抗旱系数与农艺指标品种旱地产量得到较好的结合,更适合育种工作者应用.     

Design on Enterprise Informationization Estimates the Model of Composite Index

This peper commentaried some of our country comparatively well-known enterprise informationization estimate theory,point out,there is existing the question of informationization estimates,that the achievement can't guarantee "appropriate informationization" establishing and enterprise informationization sustainable development,It propose the three-dimensional enterprise informationization estimate the theory and method,that includes information-based level,information-based quality and information-based development potentiality.     

北京地区夏季野生食用菌生物指标的测定

为了扩大对野生资源的评价和利用,2009年夏季在北京周边山区收集常见的四种野生菌黄伞、血红铆钉菇、短柄粘盖牛肝菌和马勃的子实体。利用二喹林甲酸检测法、苯酚-硫酸法以及改良后的酶活性检测法分别测定四种子实体中蛋白质和水溶性多糖的含量、蛋白酶、磷酸酶和漆酶的活性以及凝集素的活力单位,通过对上述四种野生资源测定指标进行评价,发掘出可用于深度加工的野生品种。研究发现,黄伞子实体中蛋白质和多糖含量相对较高,分别占子实体鲜重和干重的5.12%和2.39%,并且具有凝集素的活性;四种野生菌都具有磷酸酶活性,其中马勃的酶活力最高,为339.91 U/mg;短柄粘盖牛肝菌和马勃存在微弱的漆酶活性,酶活力分别为0.341 U/mg和0.438 U/mg;在四种野生菌中未检测到蛋白酶的活性。比较结果证明黄伞子实体中的蛋白质和多糖含量较高,马勃具有较高的磷酸酶活性,这些野生资源都可以作为深加工的优势材料,进行深度研究开发。     

大都市区农业产业化联合体发展探究——以上海浦东新区为例

农业产业化联合体是一种重要的农业经营组织联盟形式,也是促进乡村振兴的重要方式。本研究旨在探索推动大都市区农业产业化联合体发展的有效举措。以上海市浦东新区农业产业化联合体发展为例,采用案例分析法和比较研究法,从发展目标、发展模式、利益共享、企业带动、品牌引领等方面梳理了上海浦东新区农业产业化联合体发展的现状,分析存在的主要瓶颈,通过借鉴国内外农业产业化联合体发展经验,提出加强组织领导,借鉴国际经验,提升配套服务,多措并举,扩充渠道等对策建议推进浦东新区农业产业化联合体的发展。     

相对病情指数划分棉花品种抗病性的统计学基础

对多年棉花品种的黄萎病抗病性鉴定资料分析表明,同一个品种的黄萎病病情指数年度间差异变化较大。8年的鉴定资料统计结果表明,中棉所12的病情指数年度间变异系数为37.4％,冀棉11为33.3％,方差分析表明它们的病情指数年度间变异极显著。对1992—1997年中棉所12的病情指数进行概率统计,其总体平均数的估计值为62.0,95％置信区间为[58.4,65.6];99％置信区间为[57.2,66.8]。利用本文方法计算的相对病情指数来表示棉花品种的黄萎病感病性,与利用病情指数表示方法相比,可以将年度间变异降低60％,发生概率p=0.997。本方法划分的抗病性不同于目前通用的以一个年度田间病情指数划分的品种抗病性,而是概率保证下的抗病性,具有深层的数理统计的意义。     

A Statistical Model for Multi-paths Distribution under Mobile Environment

This paper presents the distribution function of multi paths by use of two stochastic processes. The first process which is a Poisson process presents the paths occurring, and the second one which is an exponential process presents the paths standing. If the maximal paths are infinite, the Poisson distribution can be concluded. The notable error exists between the Poisson model and the measurement result. So the Poisson model is modified depending on the fact that the arrival rate decreases and the standing time get longer with the increase of arrived paths. The numeric results verify the consistence between the modified model and measurement.     

Manufacturing Output Indexes for a Metropolitan Area: A Look at New Economic Indicators

The purpose of this paper is to construct monthly manufacturing output indexes for a metropolitan area, employing a method used by the Federal Reserve Banks to construct regional manufacturing indexes. The Tulsa metropolitan area is the region considered. The index of total manufacturing output is included in a vector autoregression model of the Tulsa economy. The results indicate that the linkages between manufacturing activity and non-manufacturing employment differ from the linkages between employment in those sectors, and that since the early 1980s both sectors have become less sensitive to changes in the price of oil.     

A Simplified Thermoelastic Model for Composite Iaminated Shells

To effectively analyze the one way coupled thermoelastic problem for composite laminated shells, a simplified thermoelastic shell model based on the variational asymptotic method (VAM) was developed. The 3 D energy functional for composite laminated shell was established according to the Hamilton extended principle. Then the 3 D energy was asymptotic expanded into a series of 2 D approximation energies by taking advantage of the inherent small parameters. Finally, the approximate energy was converted to the form of Reissner Mindlin model, and the 3 D recovery relationships were deduced to accurately predict the 3 D field distribution along the thickness direction. The cylindrical bending example of a four layer composite laminated shells under the sinusoidal surface load and temperature field shows that the modeling speed is fast (equivalent single layer model, which can reduce two or three order calculations compared to the 3 D finite element method), and the nonlinear approximation ability is excellent (convergent to the exact solution).     

中国集约高产农田生态健康评价方法及指标体系初探

如何科学评价目前中国粮食主产区高产农田的生态健康现状与问题,为制定科学合理的对策,促进中国粮食主产区农业可持续健康发展、保障国家粮食安全是当务之急。目前关于农田生态系统健康评价从土壤-作物-环境三大子系统综合考虑构建评价指标体系的研究很少,没有比较完善的、为大家公认的关于农田生态健康状况评价的指标体系。采用总体分析法,查阅统计了国内外关于农田生态健康评价研究的相关指标。在此基础上,为了使评价指标更加切合中国三大平原粮食主产区高产农田土壤、作物以及环境的健康问题,采用专家问卷调查法,最终初步确定了中国农田生态健康评价指标体系,每个区域的评价体系都有22个指标,三大平原指标之间有所区别,充分体现了整体的一致性和区域的特殊性,使得指标体系更具实用性和针对性,可为该领域的研究与决策提供科学参考。     

The Changing Scale of Livestock Production in and around Corn Belt Metropolitan Areas, 1978–97

This research examines changes in four sectors of livestock production, pork, dairy, fed cattle, and beef cows, from 1978 to 1997 by county metropolitan character. Relative changes in the amount of production and the number of producers in a county as well as changes in the average scale of production are examined. The purpose is to identify whether structural differences have emerged between metropolitan and nonmetropolitan Corn Belt counties as a result of industrialization in livestock production. The analysis identifies a divergence in the amount and scale of pork production in metro versus nonmetro regions from 1987 to 1997, coinciding with a period of substantial industrialization in that sector. Little divergence is identified in the scale of dairy, fed cattle, and beef cows operations during the same time period. The findings have implications for farmland preservation and agricultural viability in exurban regions of the Corn Belt.