Estimating Traffic Emissions Using Demographic and Socio-Economic Variables in 18 Chilean Urban Areas

A macro-scale methodology for vehicle emissions estimation is described. The methodology is based on both correlations between activity level and PM, CO, THC and NO _x vehicle emissions and relationships between demographic and socio-economic variables and transportation activity level. First, pollutant emissions were correlated with transportation activity, expressed as vehicle-km/year, using existing data collected from mobile sources emission inventories in nine urban cities of Chile. Second, demographic and socio-economic variables were pre-selected from those that could intuitively be correlated with vehicle activity level and considering the data availability. Using the individual R ² correlation coefficient as variable selection criterion, population, the number of vehicles, fuel consumption, gross domestic product, average family incomes and road kilometers were finally chosen. A different set of explicative variables was considered for different vehicle categories, based on the selection criterion above mentioned. Then, correlation functions between these variables and transport activity were obtained by non-linear Gauss–Newton least square method. This methodology was applied to eighteen provinces of the country obtaining total annual emission for mobile sources, divided into six main vehicles categories.     

Is Maternal and Child Health Service use a Causal Gateway to Subsequent Contraceptive use?: A Multi-Country Study

The purpose of this study is to examine the relationship between MCH service utilization and contraceptive use in five countries: Bolivia, Guatemala, Indonesia, Morocco, and Tanzania. The analysis is carried out at the level of the individual woman, with contraceptive-use status modeled as a function of: (1) the availability, quality, and packaging of MCH and family planning services; (2) community- and individual-level determinants of health service and contraceptive use; and (3) intensity of prior MCH service use. Data for the analysis comes from DHS data on women of reproductive age linked with data from service-availability surveys. We use full-information, maximum-likelihood regression techniques to control for the effects of unobserved heterogeneity that might otherwise bias our estimates. In three of the five countries (Morocco, Guatemala, and Indonesia) the results of the analysis suggest that the intensity of MCH service use is positively associated with subsequent contraceptive use among women, even after controlling for observed and unobserved individual- and community-level factors. This result lends support to the proposition that, at least in the context of these three countries, the intensity of MCH service per se use does have a “causal” impact on subsequent contraceptive use, even after controlling for factors that “predispose” sample women to use health care services.     

Welfare Receipt Among Children Living with Grandparents

Considerable increases in the numbers of children living with grandparents have prompted concerns over their economic well-being and grandparents’ use of welfare programs. Using data from the Survey of Income and Program Participation, I profile the economic well-being of children living with grandparents and estimate the likelihood of receiving two welfare programs: food stamps and Temporary Assistance for Needy Families (TANF). Findings suggest that identifying the exact living arrangements of children is pivotal to understanding differences in economic disadvantage and welfare receipt among children living with grandparents. Although children in grandmother-only, no parent present families are the most likely to be poor, they are not the children most likely to receive welfare. The children most likely to receive welfare live with their single mothers and grandparents in three-generation households.     

SMPD Scenarios of Spatial Distribution of Human Population in China

Three scenarios of spatial distribution of human population in China are developed in the years 2010 and 2020, respectively by means of the method of surface modeling of population distribution (SMPD). Each one of the SMPD scenarios is defined as a plausible alternative future under particular assumptions of elevation, water system, net primary productivity (NPP), urbanization, transport infrastructure development, and population growth. The SMPD scenarios show that if population could freely migrate within the whole China, the balanced ratios of population in the western region, the middle region and the eastern region to total population in the whole China would be 16%, 33% and 52%, respectively.     

Buying membership in the transnational community:migrant remittances,social status,and assimilation

I analyze the effects that social status and immigrant incorporation have on migrant remittances. Understanding remittances as one type of transnational practice, I conceptualize them as the fee that migrants pay to remain members of the transnational community. I define a “status hypothesis” in terms consistent with the view of transnational engagement as a response to status loss, predicting a negative association between increases in social status and remittances. Since immigrant incorporation usually entails status gain, this hypothesis is consistent with the conventional assimilation paradigm. While the status hypothesis could be linked to the new economics of labor migration as well, it collides with the view of transnationalism as an alternative path for successful immigrant incorporation. Using data on male Mexican migrants to the United States, I find enough support for the status hypothesis, indicating the need to clarify the ultimate meaning of transnational practices. In addition, my analysis shows that there is room to integrate economic theory, the assimilation paradigm, and the transnational perspective into a comprehensive understanding of transnational engagement.     

By what measure? family time devoted to children in the united states

We argue that previous research on time devoted to child care has paid insufficient attention to the conceptualization of care time. Three separate problems are evident. First, the conventional focus on explicit activities with children distracts attention from the larger responsibilities of "passive" care, which ranges from time when children are sleeping to time when they are in the same general area but are not engaged in an activity with parents. Second, the empirical analysis of activity time focuses almost exclusively on parents, overlooking the role of relatives such as grandmothers and siblings. Third, the measurement of active care time often ignores the impact of overlaps among both care providers and recipients. Our analysis of the Child Development Supplement of the Panel Study of Income Dynamics sheds light on these three problems and presents new measures of passive and active care time.     

Parental divorce and subsequent disadvantage: A cross-cohort comparison

Although many studies have examined the link between parental divorce and subsequent well-being, some theories of the effects of divorce suggest that the negative associations should have declined over time. However, few studies have examined the extent to which the associations have remained stable over time. Using data from two British cohorts, we analyzed both shorter- and longer-term outcomes of children who experienced parental divorce and the extent to which the associations have changed over time. Estimating similar models for both cohorts, we found little evidence of any change in the size of the relationship as divorce became more commonplace.     

Wives who outearn their husbands: A transitory or persistent phenomenon for couples?

In what percentage of married couples do wives outearn their husbands, and, moreover, how persistent are these patterns? This study systematically examined variation in point-in-time estimates across alternative measures of earnings, definitions of types of couples, and data sources and gauged the persistence of these patterns for a period of three calendar years using data from the 2000 Current Population Survey and the 1996–2000 Survey of Income and Program Participation. Among the findings are that in 19% to 30% of all married couples, wives have higher earnings than their husbands. In 60% of such couples, this arrangement persists over the three-year period; for the rest, this arrangement is transitory.     

Immigration and the American century

The full impact of immigration on American society is obscured in policy and academic analyses that focus on the short-term problems of immigrant adjustment. With a longer-term perspective, which includes the socioeconomic roles of the children of immigrants, immigration appears as one of the defining characteristics of twentieth-century America. Major waves of immigration create population diversity with new languages and cultures, but over time, while immigrants and their descendants become more "American," the character of American society and culture is transformed. In the early decades of the twentieth century, immigrants and their children were the majority of the workforce in many of the largest industrial cities; in recent decades, the arrival of immigrants and their families has slowed the demographic and economic decline of some American cities. The presence of immigrants probably creates as many jobs for native-born workers as are lost through displacement. Immigrants and their children played an important role in twentieth-century American politics and were influential in the development of American popular culture during the middle decades of the twentieth century. Intermarriage between the descendants of immigrants and old-stock Americans fosters a national identity based on civic participation rather than ancestry.     

Did fertility go up after the oklahoma city bombing? An analysis of births in metropolitan counties in Oklahoma, 1990–1999

Political and sociocultural events (e.g., Brown v. Board of Education in 1954 and the German reunification in 1989) and natural disasters (e.g., Hurricane Hugo in 1989) can affect fertility. In our research, we addressed the question of whether the Oklahoma City bombing in April 1995, a man-made disaster, influenced fertility patterns in Oklahoma. We defined three theoretical orientations--replacement theory, community influence theory, and terror management theory--that motivate a general expectation of birth increases, with different predictions emerging from time and geographic considerations. We used two different empirical methodologies. First, we fitted dummy-variable regression models to monthly birth data from 1990 to 1999 in metropolitan counties. We used birth counts to frame the problem and general fertility rates to address the problem formally. These analyses were organized within two design structures: a control-group interrupted time-series design and a difference-in-differences design. In these analyses, Oklahoma County showed an interpretable, consistent, and significant increase in births. Second, we used graphical smoothing models to display these effects visually. In combination, these methods provide compelling support for a fertility response to the Oklahoma City bombing. Certain parts of each theory helped us organize and understand the pattern of results.