美国棉花产量预报技术研究

为向外贸部门提供经营决策的科学依据，本文在研究美国棉花带气候条件与棉花产量关系基础上，建立了美国棉花产量的统计预报技术方法，其中包括数理统计、遥相关因子、美国气候因、相似分析、专家评估和社会经济计量等新技术的具体应用，从而获得了较高的预报准确率和较好的社会经济效益。     

Heterogeneity in the local employment multipliers in the United States

Recent studies have found evidence of a local employment multiplier’s effect. For the most part, these studies provide an average estimate for all labor markets. In this paper, we examine how the average local employment multiplier, the effect of an exogenous increase in employment in the tradable sector on total employment, depends on the characteristics of the local labor market. Specifically, we estimate the average multipliers for coastal, noncoastal, large, and small metropolitan statistical areas (MSAs) across different time periods using the data of 333 US MSAs. Overall, we find a reduced form of local employment multiplier ranging from 1.38 to 2.24, which is within the range of typically estimated local employment multipliers. In addition, the characteristics of the local labor market matter. The local multipliers appear larger in noncoastal and large MSAs. For small and coastal metros, the multiplier is closer to 1.5 than to 2.0 while in the case of large and noncoastal metros, it is closer to 2.0 than to 1.5. The local multipliers are also sensitive to the time period considered.     

Corporate-Merger-Defined Core-Periphery Relations for the United States

ABSTRACT A modified core-periphery model of economic spatial relations is tested by an examination of U.S. corporate merger behavior from 1955 to 1980. A core, a number of semicores, semipheripheries, and a periphery describe the merger-defined relationships between states and SMSAs. The core-periphery structure is not stable across time and is related to the merger cycle.     

Firm Networks and Korean Subsidiaries in the United States

ABSTRACT This article examines the role of intra‐, inter‐, and extra‐firm networks in influencing the location and investment of Korean firms and their subsidiaries in the U.S. Based on a survey of Korean subsidiaries in the U.S. in 2004, this article finds that inter‐firm relations with customers and suppliers, as well as intra‐firm relations in the form of parent firms’ knowledge of the U.S. play an important role in locational decision. Korean subsidiaries’ relationships with U.S. places are strongly influenced by home‐based practices that favor hierarchical intra‐firm organization and embedded sociopolitical extra‐firm relationships that emphasize blood, school, and regional ties. Location in U.S. industrial clusters does not increase Korean subsidiaries’ level of autonomy from parent firm's control that could help facilitate the sourcing of local knowledge and resources. Only improved intra‐firm network positionality positively contributes to increased subsidiary autonomy. Overall, the findings indicate that while inter‐firm relations may be important in locational selection among Korean firms, network norms are largely maintained through intra‐firm and, to a lesser extent, extra‐firm relations.     

The Structure of Agricultural Unemployment in the United States

This paper examines whether employment in agriculture is more sensitive to fluctuations in the level of economic activity than is employment in the economy as a whole. The analytical framework of the investigation rests on two functional relationships between unemployment and economic activity introduced by Thurow. The results indicate that agricultural unemployment is impacted by variations in economic activity to the same extent as is total unemployment. Finally, when subjected to a stability test, the underlying structural relationships are deemed to be stable over the sample period (1948-1988).     

Intensive cropping of maize in the Southeastern United States

The long growing season of the southeastern Coastal Plains allows planting of a second crop after spring-planted maize (Zea mays L.). Second crops have been shown to reduce erosion and prevent leaching of nutrients and pesticides. Maize grown with a second annual crop might also have a yield advantage over mono-cultured maize. Seven tillage/cropping systems were compared. They included disking for weed control, disking for seedbed preparation, or no disking. Double-cropped treatments included sunflower (Helianthus annuus L.), soybean (Glycine max. L.), a cover crop [crimson clover (Trifolium incarnatum L.)] or no double crop. Double-cropped soybean yields did not respond to irrigation. They averaged 0.63 Mg/ha over 4 years. This is less than half of the local non-double-cropped yields. Sunflower yields averaged 0.89 Mg/ha, also less than non-double-cropped yields (1.0–2.5 Mg/ha). The best continous maize yields (7–8 Mg/ha) were from treatments with disking in some phase of the operation. Treatments with lower maize yields generally had higher plant nutrient contents. Double-cropped maize yields significantly (P<0.10) outyielded mono-cropped maize yields in two of the three years. In 1984, a dry year, the minimum tillage treatment had lower tensiometer readings than the conventionally tilled treatment.     

The Effects of Environmental Regulation on Business Location in the United States

This article empirically examines whether variations in state environmental regulations have affected the location of manufacturing branch plants by the Fortune 500 companies. Using several measures of environmental regulation, no statistically significant effects of environmental regulation on business location are found. For most manufacturing industries, the estimates are precise enough to rule out the possibility of large effects of environmental regulation on business location. For highly polluting industries, however, the variance in the estimates is quite large. We cannot rule out the possibility of effects of environmental regulation on the location of highly polluting industries that are large enough to be important to policymakers.     

The economic benefits of forage improvement in the United States

The United States is a large country with a diversity of forage ecosystems and forage species to fill the varied management options within each ecosystem. For example, the American Seed Trade estimates seed of 5,500 varieties representing 1,500 grass and 4,000 legume species are produced annually. The economic benefits of forage improvement are both direct (seed and hay sales) and indirect (saleable animal products, nitrogen fixation and conservation uses). The benefits of improving forages through breeding are likewise important due to the current use of improved varieties to underpin these systems and their direct and indirect products. Because of the diversity of species and management systems, only a few case studies were examined in this paper to estimate these benefits. These were the alfalfa (Medicago sativa L.) industry (economic value of US$8.1 billion per year), the forage and livestock systems of the southeastern USA (economic value estimated overall at US$11.4 billion per year), and switchgrass (Panicum virgatum L.) and its potential use as bio-energy feedstock (economic value of needing an additional 28 million acres of production to supply the estimated future feedstock needs). The overall conclusion is that the economic benefits from forage improvement in the USA have been, and continue to be, immense. However, future resources are going to fewer crops, and these crops are the ones that have greater economic value and where biotechnology can be applied. This will favor alfalfa and penalize forage grasses. Even for crops with an identifiable path to market, this concentration of resources in fewer hands requires development of consortia where organizations can leverage their resources with others who possess complementary resources. The Consortium for Alfalfa Improvement is a good example of how this could work.     

浅淡美国玉米种质在中国玉米育种中的作用

玉米品种的换代更新离不开种质的创新,外来种质是我国玉米育种的重要基础材料来源.本文简要分析了自20世纪70年代以来我国引进的美国优良种质在我国玉米育种和生产上取得的成就、种质特点及改良的途径.     

美国市民农园的发展、功能及建设模式初探

城市农业的发展日益受到人们关注,市民农园作为其重要形式之一,是由一群人在同一地块上开展耕种的社区活动,已成为协调城市人地关系的一种有效途径。为借鉴国外城市农业发展经验,本文对美国市民农园的发展、功能、类型进行了梳理,对洛杉矶14个市民农园营建模式进行了系统调查。研究得出：美国市民农园已有百年历史,对美国社会、经济和文化的发展影响深远;不仅具有生产、生态和景观功能,而且有较高社会文化价值;有多种营建模式,管理体系较为完善,用地属性多为公有,以种植食用植物为主,重视节约管理和有机种植;同时亦有诸如租约等弊端影响其长远发展。这对中国城市农业发展、绿地规划具有借鉴意义。该文从城市化、老龄化及和谐社区建设等角度,认为市民农园是中国城市农业和城市规划重要的实施方式,具有一定社会需求,并提出了一些建议。     

中美两国马铃薯种薯质量控制对比分析

马铃薯种薯是生产中最重要的组成部分.我国制定了关于脱毒种薯的国家标准,各地也制定了若干地方标准,但都缺乏有效的质量检查方法和管理手段,主要原因在于检测费用太高,导致种薯标准形同虚设.美国威斯康辛州通过加强环境管理,采用种薯异地繁殖,用目测法判断质量,费用少,简便易行,值得借鉴.     

Estimated inventory of livestock and poultry manure resources in the United States

Livestock and poultry manure is a valuable resource which may be effectively used to supplement or replace inorganic fertiliser and livestock feed, or for energy production. Ineffective utilisation may result in a wasted resource or pollution from improper storage and disposal.About 100 million metric tons of manure (dry basis) were estimated to have been voided by livestock and poultry in the US in 1974. About 47% was produced by beef cattle on range, 23% by dairy cattle and 12% by hogs. The estimated amounts of nitrogen, phosphorus and potassium voided with the manure were 3·7, 0·9 and 2·2 million metric tons, respectively.Significant changes often occur in the amounts of manure and nutrients after voiding, when considering different lengths storage time and different types of waste handling system. The quantity of manure in 1974 decreased about 11% to 90 million metric tons as a result of these losses. Nitrogen decreased to 2·4 million tons. Approximately half the manure was estimated to have been produced in areas where economic collection was feasible. The remainder was voided by animals on range and pastureland.In 2260 counties of the United States in 1974, at least 50% of the manure was produced by one commodity. In almost 70% of those counties, beef cattle on pasture or range produced the majority of the manure. Considering only the manure which is economically recoverable, in about 56% of the 2168 counties dairy cattle were the major contributor, followed by feeder cattle, hogs and broilers in decreasing order of importance.Estimated concentrations of manure on available cropland were highest in the New England region, followed by the mid-Atlantic, south Atlantic and Pacific regions. The number of livestock and poultry could increase from one-third to about five times—depending on geographic region—and still not exceed the minimum agronomic loading rate.     

Migration regions and interstate labor flows by occupation in the United States

"This paper investigates the migration patterns of occupational groups [in the United States]. The results confirm previous analyses of the differences in movement behavior between occupations but, in addition, show that this variation is a function of the industrial sector of employment. The chief aim of the paper, however, is to uncover the geography of labor flows for different occupational groups using a principal components analysis of interstate flow matrices....Results indicate that migration regions vary by occupation and industry and we argue that these differences reflect job information flows and regional employment structure for various classes of labor." Data are from the Public Use Microdata Sample A taken from the 1980 census.     

Immigration and Ethnic Entrepreneurship: A Comparative Study in the United States

Using Singer's typology of different types of immigration gateways, this study mainly addresses how metropolitan area conditions impact ethnic labor force entrepreneurial choices across ethnicity and gender, within the contexts of different types of immigration gateways. Employing the 5 percent 2000 Integrated Public Usable Microdata Samples and a multilevel regression strategy, this study demonstrates that different types of immigration gateways have distinctive impacts on ethnic entrepreneurship. After controlling for both personal‐ and metropolitan‐level characteristics, it is found that whites and blacks are more likely to own businesses in newer immigration gateways, while Hispanics and Asians are more likely to do so in the more established gateways. In addition, differences as to the interaction effects of gender and regional labor markets are the most significant for blacks and Asians. Such interaction effects reshape gender differences in business ownership across ethnic groups.     

Spatial aspects of post-1970 work force migration in the United States

The author examines the spatial distribution of population and economic activities in the United States, with particular reference to the phenomenon of renewed growth in nonmetropolitan areas. The study is based on an analysis disaggregated by region. Data are from the one percent Continuous Work History Sample     

The Japanese Banking Presence in the United States and Its Regional Distribution

The Japanese presence in U.S. banking markets is of particular significance. Japanese represent slightly over one-half of the total foreign banking presence in the U.S., concentrated in two states (California and New York). The growth of Japanese direct investment in the U.S. and the yen/dollar exchange rate appear to be the two most important economic factors influencing this rising Japanese banking presence. Japanese legislation liberalizing the flow of investment in and out of Japan, beginning in 1980, is a very important factor. Also, the International Banking Act of 1978 may be important in explaining the recent growth of Japanese bank branches in California.     

Telecommunications Infrastructure in the Southeastern United States: Urban and Rural Variation

The capabilities of central office (CO) telephone switches in four southeastern states (Kentucky, Mississippi, North Carolina, and Tennessee) provide detail on spatial variation in telecommunications technologies. A proposed six‐level hierarchy of switch capability was used. Switches with digital capability are concentrated disproportionately in metropolitan areas, largely in response to larger numbers of business establishments. The overall picture in the Southeast is one of tremendous variation—variation across states and variation within the four states being studied. Rural (nonmetro) counties generally, but not always, have both fewer switches overall and fewer switches with digital capability. North Carolina and Tennessee, the two most urban of the four states, also have seen the greatest entry by new telecommunications competitors. These two states have the largest percentages of advanced (digital) switches in both metro and rural counties. At the county level, the number of switches is primarily a function of a county's population but, even more significantly in three states, of the number of business establishments in the county. On the whole, it is residents of metropolitan—not rural—areas who are most likely to be served by newer forms of digital telecommunications.