Relative humidity as an environmental factor determining the microhabitat of the nymphs of the rice brown planthopper,Nilaparvata lugens (St?l) (Homoptera: Delphacidae)

Summary Microhabitat of the nymphs and the adults of the rice brown, planthopper,Nilaparvata lugens is known to be the lower parts of rice plants. In this study, possible environmental factors determining the range of the microhabitat were experimentally analyzed by using the nymphs under laboratory conditions. Thirty individuals of the 1st or the 3rd instar nymphs were released to a potted rice plant covered with a transparent acrylic cylinder. When the top of the cylinder was kept opening (open condition), the temperatures in the cylinder were almost constant, and relative humidities in the cylinder decreased with the increase of the height from the water surface of the pot. In the open condition, most nymphs and all exuviae were found on the basal parts of rice plants where the humidity was more than ca. 90% r.h. When the top of the cylinder was kept closing with parafilm (closed condition), the temperatures in the cylinder were almost constant, and relative humidities in the cylinder were more than 95% r.h. In the closed condition, the nymphs and the exuviae were distributed sparsely to the whole parts of rice plants. In both of the open and the closed conditions, patterns of nymphal distributions on rice plants during the dark regime were the same as those during the light regime under 25±2°C and 16L∶8D. Four different temperatures ranging from 20°C to 35°C did not influence on the microhabitat in the open condition. It was concluded from the results that relative humidity is the important environmental factor to determine the microhabitat of the nymphs ofN. lugens which showed to prefer very humid condition more than ca. 90% r.h.     

A New Generalized Variance Approach for Measuring Multidimensional Inequality and Poverty

The paper suggests a new generalized variance concept for measuring multidimensional inequality of a stratified society, based on multivariate statistical methods, where the members of society form a cloud in the oblique space of dimensions of inequality, such as income, expenditure and property. The cloud presents the multidimensional inequality capsulized in the cloud. The goal is to condense all the inequality information embodied by the cloud into a composite compact metric characterizing both the shape and the inner structure of the cloud. Contrary to the conventional literature that considers multidimensionality as a unidimensional weighted combination of the dimensions, our new composite index measures the inequality of the configuration of the points in the cloud. Our aim is twofold. First, we introduce the Inequality Covariance Matrix (ICM) assigned to the cloud, with elements measuring the correlations among dimensions. Having ICM, we propose the Generalized Variance (GV) of ICM to measure the composite Generalized Variance Inequality (GVI) level. Second, to evaluate the stratum-specific structure of the overall inequality, we suggest a new two-stage procedure. In the first stage, we divide the total GVI into between-groups and within-groups effects. Then, in the second stage the contributions of the strata to the within-groups inequality and, the contributions of the dimensions to the between-groups inequality are calculated. This GVI approach is sensitive to the correlation system, decomposable into stratum effects and, the number of dimensions is not limited. Moreover, including the log-dimensions in the analysis, GVI yields an Entropy Covariance Matrix giving a new Generalized Variance Entropy index. Finally, the GVI of censored poverty indicators means multidimensional poverty measurement. This special complex task is not yet solved in the traditional literature so far.

     

长江三角洲人力资源的开发与整合

长江三角洲是中国人力资源新的积聚地,在人力资源上具备比较优势,但由于缺乏相应的一体化设计,长江三角洲的人力资源未能得到有效开发与整合,在人力资源日益成为第一性经济资源的今天,这种状况应尽快改变。进一步推进长江三角洲地区人力资源开发与整合须把握三个关键:即产业能级设置、城市功能定位及一体化的社会保障制度,人力资源在相应的城市环境中发挥迁移作用,而社会保障的一体化则为人力资源的流动提供软性机制。     

U.S. population: where we are; where we're going

This Bulletin reviews recent trends in the dynamics and character of the U.S. population, the outlook for the remainder of the 1980s, and prospects for longterm growth. Estimated at 232 million as of mid-1982, the U.S. population is currently growing at about 1% a year, one of the developed world's highest growth rates. Natural increase (births-deaths) still adds some 1.7 million people a year, despite the rapid postbaby boom fall in fertility to a near-record low rate of 1.9 births/woman in 1981. With increasing numbers of refugees, net legal immigration averaged 600,000/year in 1979-81 and the net inflow of illegal immigrants may now be 500,000 a year. Uncertainty over potentially large numbers of immigrants complicates projections of future U.S. population size. Currently, the U.S. death rate is at an alltime low. More than 1/2 the population now resides in the South and West. Rural areas and small towns grew faster than urban areas in the 1970s for the 1st time in over a century. Educational attainment is at an alltime high, as is labor force participation, due to increasing employment among women and the baby boom generation's arrival at working ages. The age composition of the population, with the bulge of the baby boom generation surrounded by the older "depression" generation born during the 1930s and the younger "baby bust" generation born since the end of the 1960s, presents special problems for U.S. society.     

Gender Pay Gap and Employment Sector: Sources of Earnings Disparities in the United States, 1970–2010

Using data from the IPUMS-USA, the present research focuses on trends in the gender earnings gap in the United States between 1970 and 2010. The major goal of this article is to understand the sources of the convergence in men’s and women’s earnings in the public and private sectors as well as the stagnation of this trend in the new millennium. For this purpose, we delineate temporal changes in the role played by major sources of the gap. Several components are identified: the portion of the gap attributed to gender differences in human-capital resources; labor supply; sociodemographic attributes; occupational segregation; and the unexplained portion of the gap. The findings reveal a substantial reduction in the gross gender earnings gap in both sectors of the economy. Most of the decline is attributed to the reduction in the unexplained portion of the gap, implying a significant decline in economic discrimination against women. In contrast to discrimination, the role played by human capital and personal attributes in explaining the gender pay gap is relatively small in both sectors. Differences between the two sectors are not only in the size and pace of the reduction but also in the significance of the two major sources of the gap. Working hours have become the most important factor with respect to gender pay inequality in both sectors, although much more dominantly in the private sector. The declining gender segregation may explain the decreased impact of occupations on the gender pay gap in the private sector. In the public sector, by contrast, gender segregation still accounts for a substantial portion of the gap. The findings are discussed in light of the theoretical literature on sources of gender economic inequality and in light of the recent stagnation of the trend.     

Dispersal of adult grasshoppers,Mecostethus magister, under the field condition

Summary Estimation of the number of adult grasshoppers,Mecostethus magister, was made by means of the mark-and-recapture method. The birth and death rates are possible to be estimated at the same time, but the immigration and the emigration rate are inevitably involved in these respectively. The immigration and emigration rates must be made clear to know the true birth and death rates. For this purpose the movement of the marked males in 1963 was analyzed. The grasshoppers dominantly moved in the directions of N, NW and W, and the difference in frequency among the movement directions was not so large. The distribution of the dispersal-distance relationship of each quadrate on each released day was fitted approximately to normal distribution. It could be concluded that almost all of the grasshoppers moved within the range of about 31–35m. The emigration rate from the quadrate (12×12m²) was about 0.73–0.77 and the difference in the rate among the released days was small. From these values the emigration rate from the station (84×60m²) was estimated as 0.21–0.23. Subtracting the emigration rate from the death-and-emigration rate, the true death rate was calculated. The death rate was very low until the number of males reached to the peak, then increased gradually. Supposing that immigration rate was equal to the emigration rate, the true birth rate was also estimated. But the presumption might not be pertinent, for the value of birth rates became negative.     

进城还是回村？——跨省婚迁者的空间选择

在经济社会转型、人口频繁流动的条件下,婚迁由乡到城的单向迁移转变成为城乡互动的双向流动。婚迁者留在城市还是回到乡村,要取决于多种条件。本研究通过测度跨省婚迁的性别比发现,自1990年来的20年间我国省际婚迁性别比下降近一半。全国省际婚迁性别比呈现城市-城镇-乡村两端大中间小的“微笑曲线”。在婚迁的空间选择上,男性以城市为主,女性则以乡村为主。进一步分析影响婚姻迁移的因素发现,经济变量中人均GDP对总婚迁和城市婚迁呈正向影响,城镇和乡村呈负向影响;居民收入和消费状况对婚姻迁移产生正向影响,但消费的城乡差别则对其产生负向影响;人口的城乡流动与迁移以及社会变量中各因素对跨省婚迁产生正向影响,而文化变量中的各因素则形成负向影响。     

婚前同居对初婚年龄的影响研究 ——基于Heckman二阶段模型的分析

在现代社会中,初婚年龄持续攀升,婚前同居现象越来越多地出现。那么婚前同居与初婚年龄之间有没有关系?本文基于婚前同居对离婚影响的选择假说与经历假说进一步探讨两种假说与初婚年龄之间的关系。选择假说认为同居者自身特征促使他们追求思想解放,消极地影响着婚姻稳定性,因此与其同居伴侣之间并不想建立一个长期的契约。由此推测这些积极影响同居的特征因素会给结婚带来消极影响,婚前同居就会推延初婚年龄;经历假说认为共同生活的经历将会改变同居者对婚姻的认识,他们不再强烈地致力于追求婚姻的身份。他们将会接受婚前同居这种暂时性的本质。很多夫妇认为同居提供了一个婚姻的替代品,结婚的欲望由此下降。因此这也将推延初婚年龄。除两个假说外,同居者想要通过同居搜集更多对方的信息,这种想要更多地了解对方的想法也将推延初婚年龄。在理论分析的基础上,本文基于2010年CFPS抽样调查数据,采用Heckman二阶段模型纠正婚前同居的自选择性带来的偏误并检验婚前同居推延初婚年龄的研究假设。研究结果发现婚前同居使女性与男性的初婚年龄分别推迟了0.415岁与0.868岁。在控制婚前同居的自选择性后,婚前同居对女性与男性初婚年龄的影响仍然很大且显著,初婚年龄分别推迟了0.431岁与0.890岁,证明婚前同居将会提高初婚年龄。这进一步明晰了婚前同居在我国家庭形成过程中的作用。婚前同居对初婚年龄的推延作用无疑为我国全面二孩政策下出生人口数量增长带来消极影响。     

The equivalence of united states census data for persons of Russian stock or descent with American Jews: An evaluation

While the U.S. Bureau of the Census has had a long-standing policy of abstaining from enumerating the religious beliefs or backgrounds of the American people, at least two-thirds of the Jewish population of the United States has been enumerated in decennial censuses and sample surveys in the guise of persons of Russian stock or origin. This has come about through the migration policy of the old Russian Empire and the statistical categories utilized by American immigration authorities and by the U. S. Bureau of the Census for immigrants and their children. Comparisons between the returns from an ethnic survey and a survey on the religious composition demonstrate the close congruence between persons of Russian stock or descent and American Jews on the national level.     

Patterns of prey utilization in a web of orb-weaving spiderAraneus pinguis (Karsch)

Summary The pattern of prey utilization of the orb-weaving spiderAraneus pinguis was studies by comparing between arthropods restrained in the empty webs (spiders were removed) and those unattacked in the intact webs (spiders were not removed). The number of arthropods was larger in the empty webs than in the intact webs. In the empty webs, web area, mesh width, number of radii, and signal thread length were presumed to affect the number of arthropods left in a single web. As for the intact webs, web area, mesh width, and web-exposure time were important factors. In the empty webs, the density of arthropods decreased away from the hub. On the other hand, the density of unattacked arthropods in the intact webs was the same throughout the web. Arthropods in the empty webs were larger than those in the intact webs. The upper limit in size of unattacked arthropods increased along with the distance from the hub in the intact webs, but not in the empty webs. These results indicate increase in the minimum size of eaten arthropods increased in the former. This positive sizedistance relation may have resulted from the adaptive switching of spiders’ alternative foraging methods (i.e., the rapid attack at encounter and the later eating during web deconstruction) on the basis of the prey profitability.     

美国、日本经济增长方式转变比较及启示

当今世界,美国、日本两国经济分别以世界第一、第二位次形成世界经济两大极。美国和日本的经济增长方式都经历了从粗放型向集约型的转变,但两国的转变不尽相同。研究两国经济增长方式转变的差异和成功经验,可以为我国经济增长方式转变提供借鉴。     

Public policy and the total fertility rate: cross-sectional evidence from the LDCs

A framework developed by Easterlin for the analysis of fertility in developing societies is modified and then tested using a sample of 65 less-developed countries. The focus is on assessing the impact of public policy on the national fertility rate. Public policy is reflected in the average levels of education and health in the population and in the condition of the national family planning program. To test for threshold effects with respect to socioeconomic development, the sample is divided on the basis of the infant mortality rate. Fertility rates in those nations characterized by high infant mortality are likely to be determined more by conditions of natural fertility. Those nations with lower infant mortality, and hence greater socioeconomic development, are more likely to exhibit deliberate fertility control. The results of the regression analysis do suggest that different factors influence the national fertility rate depending upon the stage of development. For the least-developed nations, the secondary school enrollment rate, an indicator of the extent of economic mobility, and the ratio of school age children to teachers, a proxy for the national commitment to human capital formation, are important. For the more advanced of the LDCs, adult literacy and the infant mortality rate seem to predominate. For all the developing nations, however, the results confirm the importance of strong family planning programs. The paper concludes with a discussion of the policy implications of the research.     

Does Good Governance Enhance Happiness: A Cross Nation Study

The purpose of this paper is to analyze the efficiency of the countries over the period of 10 years by applying data envelopment analysis (DEA). Based on rational and factual parameters such as freedom of press, freedom of religion, percentage of export in Gross Domestic Product (GDP), index of globalization, life expectancy at birth, gender ratio etc., this paper attempts to measure the efficiency of happiness. A combination of social and economic factors has been used to measure technical efficiency. The contribution of this paper is twofold. First, it measures the relative efficiency of all the countries included in the study. The nations have been ranked as per their relative efficiency and the peer group has been formed. Second a comparison between the rich and the poor countries have been done to test empirically whether the economic growth enhances the happiness among people. Presently, more than 3,000 studies have been published on happiness and Veenhoven in 2004 created a database called World Database of Happiness. The World Database of Happiness has attempted to present the available research findings on happiness. Part of the findings on happiness in nations is available in ‘States of nations’. For the research purpose, States of Nations and the data published by have been considered. Although happiness has been quantified and the existing literature has sufficient empirical evidences of the same, in the present context, the relative efficiency has been calculated for the countries on basis of objective and subjective happiness parameters. As per the literature, happiness has two aspects (1) objective and (2) subjective. Objective parameters are external to the individuals and covers material living parameters viz. GDP growth, income, nutrition, mortality rate, literacy etc. However, Subjective indicators measure the quality of life of the individuals. These are summarized as ‘‘subjective well-being’’. The various parameters considered in the study capture different aspects of happiness. The result shows how the government can increase the happiness of the people by analyzing the behavior and expectations. People express their preference explicitly about political parties, religion believes, law and order situation, trust in official institutions etc. Although, the behavior of people largely depends upon availability of goods and services in the market, the government can make budgets according to priority or preferences of people. Another way to increase happiness can be done by analyzing the peer group, which is an outcome of DEA. This shows the nations which are similar in terms of their economic and social conditions. The government can compare the prevailing conditions in different countries that improve the condition in their respective country. This could be an effective method as some of the parameters can be replicable in order to make people happier. The limitation of this study is lack of availability of data for many countries. As the number of countries increases, a change in the relative efficiency can be observed. Therefore, a future study can be conducted where the relevant data can be collected and a more global result can be obtained.     

论西部民族地区人力资源的开发与人力资本的形成

人力资本积累是经济发展最重要的推动力 ,而西部民族地区的总体人力资本水平还很低 ,与沿海发达地区的“知识差距”在不断扩大。通过制定缩小知识差距的发展战略 ,注重人力投资的制度创新 ,加大人力投资强度 ,调整人力资本投资结构 ,加快西部民族地区劳动力市场建设 ,促进劳动者的自由流动 ,改革人才配置制度 ,就能有效地促进西部民族地区人力资源的开发和人力资本的积累。     

People's Republic of China Law on Population and Birth Planning

Plans by the Chinese government for drafting and passing a national law on population and birth planning were first reported in 1978. Progress toward that politically sensitive goal has been, however, very slow. During the past two decades, the legal basis of China's birth planning program was limited to provincial legislation. By the late 1990s, birth planning was the only major national policy area that did not have national enabling legislation. In January 2000 the State Birth Planning Commission sent a draft of the law on population to the State Council for interagency review and party approval. At the end of 2000, the National People's Congress placed the law on its 2001 agenda. After the required multiple reviews, and with some changes, the Standing Committee of the NPC passed the Law on Population and Birth Planning on 29 December 2001, and on the same day President Jiang Zemin signed and promulgated the Law. The Law is to come into effect on 1 September 2002. The background and significance of this legislation are discussed in detail in the opening article in the present issue of this journal. The author of the article, Edwin A. Winckler, also prepared an English translation of the Law on Population and Birth Planning. This translation is reproduced below. It is followed by a note by the translator.     

Interpolation and forecasting of population census data

Since population censuses are not annually implemented, population estimates are needed for the intercensal period. This paper describes simultaneous implementations of the temporal interpolation and forecasting of the population census data, aggregated by age and period. Since age equals period minus cohort, age-period-cohort decomposition suffers from the identification problem. In order to overcome this problem, the Bayesian cohort (BC) model is applied. The efficacy of the BC model for temporal interpolation is examined in comparison with official Japanese population estimates. Empirical results suggest that the BC model is expected to work well in temporal interpolation. Regarding the age-period-cohort decomposition of the Japanese census data, it is shown that the cohort effect is the largest while the other two effects are very small but not negligible. With regard to the forecasting of the Japanese population, the official population forecast considerably outperforms the BC forecast in most forecast horizons. However, the pace of increase in root mean square error for longer-term forecasting is larger in the official population forecast than in the BC forecasts. As a result, a variant of the BC forecast is best for 10-year forecast.     

A look at Philippine population in the year 2000

The major subject areas explored by the University of the Population Institute were fertility, mortality, the Filipino family and nuptiality, migration and urbanization, and the structure and growth of the labor force. Data were extracted primarily from the Philippine Censuses (1903-1970) the National Demographic Surveys of 1968 and 1973, and special surveys conducted by the Institute research team. On the basis of the findings, a range of alternative population futures is projected for the year 2000, with their respective policy implications. The estimate of the crude birthrate for 1970 placed the range at between 39.3 and 42.7. The crude birthrate may have declined by 21-23% in the last 70 years, and by almost 13% in 1960-1970 alone. On the national level, fertility rates will continue to decline if the trend of delayed marriages continues. Fertility was found to decrease with the introduction of the positive socioeconomic factors that make some regions more developed than others. The present low levels of mortality have decreased its importance in relation to fertility. Mortality prospects can be improved by several policy actions which are presented here in the order of priority. Current evidence points strongly to an increase in the proportion of single individuals who delay marriage and those not planning to marry at all. The record of internal migration in the Philippines during the 20th century has been dominated by the phenomenon of urbanization, which increased from 13% in 1903 to 33% in 1970. An effort needs to be made to achieve greater rural-urban balance. The country's high population growth has increased the number of job seekers in recent years; the expansion of the regional labor force in the 1960-1970 decade was highly correlated with the growth of regional populations. Fertility, mortality, nuptiality, migration, and urbanization are the major factors determining the growth and structure of Philippine population. Alternative projections for each of these factors were combined in different ways and 3 alternative scenarios for population in the year 2000 are presented.     

Initiation of the process of adult role entry

Among the most significant events marking the transition to adulthood are role changes involving the assumption of adult responsibilities. These include entry into the adult roles of worker, spouse, and parent. Because entry into one adult role tends to have implications for entry into other adult roles, the ages at which these role changes occur are related. It is therefore instructive to view the process of adult role entry as a process that is initiated when the first of several role changes occurs. The purpose of this paper is to examine initiation of the process of adult role entry. Data from a fifteen-year followup study of high school students originally surveyed in 1957–58 and resurveyed in 1973–74 are analyzed to determine which of several role changes initiated the process of adult role entry and the age at which the process was initiated for cohorts born during the early 1940s. A model predicting the age at initiation of the process is estimated, and the parameters of that model are compared with the parameters of comparable models predicting educational attainment and the timing of exit from the student role.This research was supported by Grant Nos. R01-HD16164 and R01-HD18596 from the National Institute of Child Health and Human Development. I am indebted to Peter H. Rossi and James S. Coleman for their assistance and support during the collection of data on which the research was based. The assistance of Peter J. Hodsdon and Lillian L. Southwick in processing the data and Pamela Navatta in typing the paper is also gratefully acknowledged.     

Speciation and evolutionary dynamics of asymmetric mating preference

Asymmetric mating preferences occur in two closely related species, if females of one species are highly selective against males of the second, while females of the second show less selection against males of the first species. It has been suggested that such asymmetry is an indicator of common ancestry between the two species, but actual observations are contradictory and inconclusive. We developed a scenario of speciation history and asymmetric mating preference, incorporating invasion dynamicsvia frequency-dependent interspecific sexual competition. A newly isolated (derived) species may form at the periphery of the ancestral species’ distribution by invading a new range. Only a few closely related species would be expected in the new area, while many related species are expected to coexist with the ancestral species. In a peripherally derived species, female mating preferences should be relaxed through sexual character release, owing to a lack of sympatric species and a scarcity of intraspecific mating opportunities. Secondary contacts may then happen as: 1. repeated invasions, i.e. subsequent invasion by the ancestral species into the new range or, 2. backward invasions, i.e. derived species incursions into the ancestral range. Repeated invasions could lead to the coexistence of both the derived species and the newly invading ancestor. Backward invasions by the derived species can succeed only when the derived females develop a strict mating discrimination against the ancestral males. We then expect strong character displacement in the derived species. Thus, peripheral isolation and repeated invasions lead to the relaxed female mating preferences in the derived species and backward invasions lead to stronger female mating preferences in the derived species. This agrees withDrosophila data from Hawaii and the continents. Experimental data of theDrosophila arizonaemojavensis species cluster also support the hypothesis.     

Second-Generation Outcomes of the Great Migration

The mass migration of African Americans out of the South during the first two-thirds of the twentieth century represents one of the most significant internal migration flows in U.S. history. Those undertaking the Great Migration left the South in search of a better life, and their move transformed the cultural, social, and political dynamics of African American life specifically and U.S. society more generally. Recent research offers conflicting evidence regarding the migrants’ success in translating their geographic mobility into economic mobility. Due in part to the lack of a large body of longitudinal data, almost all studies of the Great Migration have focused on the migrants themselves, usually over short periods of their working lives. Using longitudinally linked census data, we take a broader view, investigating the long-term economic and social effects of the Great Migration on the migrants’ children. Our results reveal modest but statistically significant advantages in education, income, and poverty status for the African American children of the Great Migration relative to the children of southerners who remained in the South. In contrast, second-generation white migrants experienced few benefits from migrating relative to southern or northern stayers.