On the relationship between the population structure and national economic development in China

The authors examine the relationship between population reproduction and the production of material goods, with particular reference to the effect of changes in the age composition of the population on the national economy and national income. An analysis of the population structure of China is presented, with consideration given to age characteristics, occupation, and urban and rural population. Suggestions for improving the population structure to achieve maximum rates of economic development are presented. Regional differences in population structure are also discussed.     

The plight of rural women: alternatives for action

Women in rural areas perform many of the agricultural tasks as well as the household care tasks. In addition to food production, looking after children, and cultivating cash crops, women also process food, carry water, make cloth, and work 15-16 hours, often much longer than the men. Too often development programs disregard the needs of women altogether. Modernization has often had a negative effect on women. They have no access to modern tools or credit. Land reform, land settlement programs, and cooperatives have neglected to consider women's interests, roles, and position. Technogical progress has resulted in creating new inequalities between rural men and women. Development has increased the workload of women who are unpaid family helpers, and time-saving mechanised device have replaced women's jobs. In most developing countries women are active in home-based industrial production. The contractor who provides the material and collects the finished product is often a wealthy landowner who also get the profits. Technical cooperation projects should be geared more directly to food processing and traditional sectors where women predominate with the goal of reducing work loads. Organization or group action is necessary to achieve economies of scale; to eliminate middle men, money-lenders and traders profiting from women's work; and, to provide solidarity and support to women otherwise isolated in their homes and on their farms.     

Motivation with regard to attitudes toward procreation among married women

The results of a sample survey on attitudes toward reproduction in Poland are presented in this two-part article. The survey, which was conducted by the Central Statistical Office in 1977, covered 9,799 women up to age 45. The women surveyed are divided into three main groups, consisting of those with positive, conditional, and negative attitudes toward having more children. The attitudes and characteristics of the women are analyzed.     

The Flow Shop Scheduling Polyhedron with Setup Times

This paper addresses the problem of improving the polyhedral representation of a certain class of machine scheduling problems. Despite the poor polyhedral representation of many such problems in general, it is shown that notably tighter linear programming representations can be obtained for many important models. In particular, we study the polyhedral structure of two different mixed-integer programming formulations of the flow shop scheduling problem with sequence-dependent setup times, denoted by SDST flow shop. The first is related to the asymmetric traveling salesman problem (ATSP) polytope. The second is less common and is derived from a model proposed by Srikar and Ghosh based on the linear ordering problem (LOP) polytope. The main contribution of this work is the proof that any facet-defining inequality (facet) of either of these polytopes (ATSP and LOP) induces a facet for the corresponding SDST flow shop polyhedron. The immediate benefit of this result is that all developments to date on facets and valid inequalities for both the ATSP and the LOP can be applied directly to the machine scheduling polytope. In addition, valid mixed-integer inequalities based on variable upper-bound flow inequalities for either model are developed as well. The derived cuts are evaluated within a branch-and-cut framework.     

Employment location choices: Factors associated with the likelihood of homebased employment

The purpose of this research analysis is to investigate the factors that are associated with the likelihood of a worker choosing homebased employment. Using a sample of 6,744 employed men and women from the 1984 Panel Study of Income Dynamics, a logit estimation procedure is employed. Factors which decrease the likelihood of being a homebased worker include minority status, higher levels of total family labor income, a high school education or less, and longer working hours. Older workers, workers without children, workers with young children under age six, the self-employed, and farmers are all more likely to be involved in homebased employment.Ramona K.Z. Heck is an Associate Professor in the Department of Consumer Economics and Housing, 133 Martha Van Rensselaer Hall, Cornell University, Ithaca, N.Y. 14853. Her current research interests include: household asset and debt formation, working families and employers' benefits, and homebased employment. She received her Ph.D. from Purdue University in 1978.The analyses in this paper are related to work in progress under the Cooperative Regional Research Project, NE-167 entitled, At-Home-Income-Generation: Impact on Management, Productivity and Stability in Rural/Urban Families, partially supported by the stations of Hawaii, Iowa, Lincoln University (Missouri), Michigan, New York, Ohio, Pennsylvania, Utah, Vermont, and the U.S. Department of Agriculture.     

Soil health as a predictor of lettuce productivity and quality: A case study of urban vacant lots

Urban agriculture offers a framework for local self-reliance and resilience in cities. However, there is a concern over the capacity of urban soil to provide sustainable and safe food production. We tested the effectiveness of several soil health indicators to predict food crop productivity and quality in vacant lots in a disadvantaged neighborhood in the city of Cleveland, Ohio. We defined soil health as a state of composite well being in terms of biological, chemical, and physical properties of the soil as they relate to crop productivity. Twelve city-owned vacant lots, three close to each of the four city schools, were selected for soil properties and plant growth analyses. Soil samples were analyzed for pH, moisture content (θv), soil texture, soil organic matter (SOM), active carbon (AC), ammonium (NH₄-N), nitrate (NO₃-N), microbial biomass N (MBN), and nematode community parameters including total (TNN), bacteria-feeding (BFN), fungal-feeding (FFN), and plant-parasitic (PPN) nematodes, number of nematode genera (NNG), and nematode food web enrichment index (EI) and structure index (SI). Lettuce was planted in the selected vacant lots and its growth was documented through measures of dry biomass, numbers of leaves/plant, and complementary subjective appearance scores related to physiological status. All measured parameters varied considerably among vacant lots except soil pH. Principal components analysis revealed that among the primary soil physical, chemical, and biological parameters, soil clay, NO₃-N, MBN, SOM, AC, TNN, BFN, FFN, and PPN contributed most to the variance of the entire dataset. There were also several positive correlations among these key soil health predictor variables: AC was positively correlated with clay, SOM, MBN, TNN, BFN, FFN and PPN, and TNN was positively correlated with AC, SOM, MBN, BFN, FFN and PPN. Of the identified primary soil health indicators, only clay, SOM, and MBN positively correlated with lettuce dry biomass, which was also positively correlated with a secondary soil health indicator, the nematode food web EI. Lettuce leaf necrosis was negatively correlated with clay, AC, SOM, MBN, TNN, FFN, and PPN, and the proportion of withered leaves was negatively correlated only with SOM. It is concluded that AC, PPN, TNN, SOM, MBN, clay, and nematode food web EI can serve as important soil health indicators that have potential for predicting crop productivity and quality in urban soils. It is also concluded that lettuce can serve as an important indicator of soil health with respect to crop productivity and quality in vacant lots.     

The Sex Ratio Transition in Asia

This article adopts a comparative perspective to review the recent increase in the sex ratio at birth (SRB) across Asia. It first describes and compares the most recent birth statistics in Asia in order to identify commonalities in the gradual rise of SRBs observed from Armenia to South Korea. This comparison provides the basis for identifying specific transition patterns in the changes in SRBs. Their recent rise is then interpreted in a social and historical framework borrowed from fertility decline and based on three preconditions: access to sex‐selection technology, preference for male births, and pressure from low fertility. On a broader plane, the process of growing imbalances in the sex composition of the population gives rise to a tragedy of the commons. This article indicates the factors that appear most likely to trigger a turnaround in this transitional demographic situation and to facilitate a return to biologically normal sex ratios in the future.     

Bayesian object matching

A Bayesian approach to object matching is presented. An object and a scene are each represented by features, such as critical points, line segments and surface patches, constrained by unary properties and contextual relations. The matching is presented as a labeling problem, where each feature in the scene is assigned (associated with) a feature of the known model objects. The prior distribution of a scene's labeling is modeled as a Markov random field, which encodes the between-object constraints. The conditional distribution of the observed features labeled is assumed to be Gaussian, which encodes the within-object constraints. An optimal solution is defined as a maximum a posteriori estimate. Relationships with previous work are discussed. Experimental results are shown.     

亚洲传播研究的蓬勃发展与未来:中国视角与日本视角(下)

中国学者与日本学者就"亚洲传播研究的蓬勃发展及未来"这一问题进行对话,其中的问题包括:亚洲传播研究蓬勃发展的情况如何?为什么亚洲传播研究者尚未终止欧洲中心传播范式的统治?亚洲传播研究的目的与意义何在?哪些亚洲本土文化概念可以为亚洲传播理论的发展做出贡献?如何评价亚洲传播研究?