Although only a small percentage of global land cover, urban areas significantly alter climate, biogeochemistry, and hydrology at local, regional, and global scales. To understand the impact of urban areas on these processes, high quality, regularly updated information on the urban environment—including maps that monitor location and extent—is essential. Here we present results from efforts to map the global distribution of urban land use at 500 m spatial resolution using remotely sensed data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Our approach uses a supervised decision tree classification algorithm that we process using region-specific parameters. An accuracy assessment based on sites from a stratified random sample of 140 cities shows that the new map has an overall accuracy of 93% (k = 0.65) at the pixel level and a high level of agreement at the city scale (R2 = 0.90). Our results (available at http://sage.wisc.edu/urbanenvironment.html) also reveal that the land footprint of cities occupies less than 0.5% of the Earth’s total land area.

En las últimas décadas del siglo XX y las primeras del presente siglo las configuraciones del mercado laboral en el orden mundial, y en Argentina en especial, han manifestado cambios importantes. Los datos señalan que, si bien los mercados de trabajo han absorbido cantidades considerables de nuevos trabajadores, se dieron tasas crecientes de desempleo o desigualdades internas considerables. En particular se han manifestado cambios estructurales en la configuración del mercado laboral y la asociación de situaciones de los miembros del hogar. Conocer la forma y distribución del trabajo en las parejas que participan en el mercado laboral es uno de los tópicos que necesita atención por afectar las áreas económicas, demográficas y sociales, en general; y en particular, para Argentina debe sumarse además el contexto socio-económico del comienzo de la presente década. El presente trabajo tuvo como objetivo realizar una aplicación de un modelo multinomial para dar cuenta del tipo de participación laboral conjunta de los cónyuges de una pareja o su no participación, con respecto a la observada para el modelo tradicional de participación masculina al comienzo de la presente década, en nuestro país. Los datos utilizados fueron del censo Nacional de Población, Hogares y Vivienda (2001). Se . . .

The escalation of the Vietnam War left young men few possible, legal options for avoiding service. One popular and understudied strategy for avoiding the draft was fathering a child. In fact, dependency deferments outnumbered student deferment at the rate of three to one by December 1970. Using Vital Statistics data on fertility and marriage rates, we examine the impact of draft policy on the age at first marriage and age-specific fertility rates. We then use the 1970 and 1980 Integrated Public Use Microdata Series of the U.S. Census to examine the impact of earlier fertility and marriage on the duration of first marriage and the probability of divorce, the total number of children born, as well as mens and women's education and wages, total household income and poverty status.

We develop two search-theoretic models emphasizing firm entry to examine the Oswald hypothesis, the idea that homeownership is linked to inferior labor market outcomes, and compare their predictions to three extant theories. The five models have surprisingly different predictions about the labor market at both the aggregate and micro levels. Using a suitable instrumental variable strategy, we estimate both micro and aggregate level regression models of wages and unemployment and compare the estimates to those predictions. We find that while homeowners are less likely to be unemployed, they also have lower wages, all else equal, compared to renters. In addition, higher regional homeownership rates are associated with a greater probability of individual worker unemployment and higher wages. The outcome of a horserace between our new search-theoretic models is mixed-the wage-posting model predicts observed unemployment impacts while a bargaining variant does a better job explaining observed wages and aggregate labor market outcomes. Overall, we conclude that firm behavior is important for understanding the labor market impacts of homeownership. Because this is the case, regional homeownership rates are not good instruments for individual tenure choice in empirical work. And while individual homeowners may have inferior labor market outcomes as compared to renters, from the viewpoint of society, higher homeownership rates may result in greater job creation and overall production, among other benefits. (C) 2008 Elsevier Inc. All rights reserved.

Internal migration is the most significant process driving changes in the pattern of human settlement across much of the world, yet remarkably few attempts have been made to compare internal migration between countries. Differences in data collection, in geography and in measurement intervals seriously hinder rigorous cross-national comparisons. We supplement data from the University of Minnesota IPUMS collection to make comparisons between 28 countries using both five year and lifetime measures of migration, and focusing particularly on migration intensity and spatial impacts. We demonstrate that Courgeau's k (Courgeau 1973) provides a powerful mechanism to transcend differences in statistical geography. Our results reveal widespread differences in the intensity of migration, and in the ages at which it occurs, with Asia generally displaying low mobility and sharp, early peaks, whereas Latin America and the Developed Countries show higher mobility and flatter age profiles usually peaking at older ages. High mobility is commonly offset by corresponding counter-flows but redistribution through internal migration is substantial in some countries, especially when computed as a lifetime measure. Time series comparisons show five year migration intensities falling in most countries (China being a notable exception), although lifetime data show more widespread rises due to age structure effects. Globally, we estimate that 740 million people, one in eight, were living within their home country but outside their region of birth, substantially above the commonly cited figure of 200 million international migrants.

This study considers the eradication of hookworm disease fromthe American South (circa 1910) as a test of the quantity-quality (Q-Q)framework of fertility. Eradication was principally a shock to the price of quality because of three factors: hookworm (i) depresses the return to human capital investment, (ii) had a very low case-fatality rate, and (iii)had negligible prevalence among adults. Consistent with the Q-Q model, we find a significant decline in fertility associated with eradication.

Historically, Forest Inventory and Analysis (FIA) has processed field inventory data at the county level and county estimates of land area were constrained to equal those reported by the Census Bureau. Currently, the Southern Research Station FIA unit processes field inventory data at the survey unit level (groups of counties with similar ecological characteristics). In short, the estimation unit has changed from an individual county to groups of counties. However, changing the estimation unit to a survey unit does not constrain the total area of each county when expansion factors are used. Here we provide a method to constrain published FIA estimates of total area at the county level to equal those of the Census Bureau. To accomplish this, we derive an expansion factor formula. Virginia serves as a case example of the techniques because of its unique geo-political boundaries.

Despite dramatic changes in education and occupational opportunities for Blacks in the United States, facilitated by affirmative action policies, the White Black earnings gap has not vanished. Although the literature on this issue has become substantial no one has yet provided a systematic examination of changes in the earnings gap that takes into consideration the concomitant changes in the occupational structure and changes in the racial composition of occupational labor markets as well as changes in characteristics of the labor force. In the present research, we use 5 waves of IPUMS data and hierarchical linear modeling to estimate changes in the effect of race on earnings between 1960 and 2000. The models focus on the interaction of time and race with earnings while controlling for individual-level characteristics (i.e. education) at the individual-level and the characteristics of detailed occupational labor markets (i.e. occupational socioeconomic status, race and gender composition, occupational earnings inequality) at the aggregate level. In order to evaluate the effect of change over time, both linear and non-linear trends in earning gaps are estimated in the labor market as a whole and separately for the public and private sectors. The data reveal that net of changes in the occupational distributions and market-relevant characteristics of Black and White men, the gaps have generally narrowed but at a declining rate. The data also reveal considerable differences in racial earnings inequality between the public and the private sectors. Whereas the unexplained earnings gap in the public sector has virtually vanished by 2000, in the private sector, the gap is still significant, although it declined over time. The findings are discussed in light of past research in order to re-evaluate the contribution of labor market attributes and sector differences to change in earnings disparities between Black and White men in the US.

I explicitly introduce racial conflict and cultural attitudes on racial diversity as determinants of destination choice to test their continued relevance to African Americans. I construct several measures of racial intolerance towards African Americans using hate crime activity and the feelings of white Americans about race extracted from a national social attitudes survey. Recognizing that African American migration may actually spawn hate crimes against them, I use a control function method with assaults on white police officers and hate crimes against Jews as instruments to correct for potential endogeneity. The results show that the probability of African American migrants choosing a city is significantly reduced by per capita hate crimes against them, the level of race-based crimes against them, by racially intolerant attitudes held by whites, and by poor evolution in whites' feelings about racial diversity all regardless of the region in which a city is located. Also striking is the previously undocumented divide among African Americans with respect to region, after controlling for racial intolerance. Those starting in the North exhibit an extreme distaste for the South at the margin, which contrasts sharply to the extreme taste for the South displayed by African Americans originating in the South.

This paper examines how involuntarily-formed social networks affect individual labor marketoutcomes. Using a new dataset of WWI draftees linked to the 1930 census, I identify theeffect of a military companys postwar employment on a veterans employment. The marginaleffect of an additional peer gaining employment, all else equal, increases a veterans likelihoodof employment by 0.8 percentage points. I develop a new framework which allows fordecomposing the social effect into its two components, the endogenous ("the effect of others'outcomes"), and the contextual ("the effect of others' characteristics"). In this setting, I findthe endogenous effect to be much stronger.

Conventional wisdom holds that one of the riskiest aspects of owning a house is the uncertainty surrounding its sale price, especially if one moves to another housing market. However, households who sell a house typically buy another house, whose purchase price is also uncertain. We show that for such households, home owning often hedges their net exposure to housing market risk, because their sale price covaries positively with house prices in their likely new market. That expected covariance is much higher than previously recognized because there is considerable heterogeneity across city pairs in how much house prices covary and households tend to move between the highly correlated housing markets. Taking these two considerations into account increases the estimated median expected correlation in real house price growth across MSAs from 0.35 to 0.60. Moreover, we show that households decisions whether to own or rent are sensitive to this moving-hedge? value. We find that the likelihood of home owning for a mobile household is more than one percentage point higher when the expected house price covariance rises by 38 percent (one standard deviation). This effect attenuates as a households probability of moving diminishes and thus the moving-hedge value declines.

Rates of self-employment differ among ethnic groups, between men and women, and by place. Using the 2000 5%, public Use Microdata Samples and hierarchical regression modeling, I examine in this study how metropolitan labor-market characteristics influence the probability of self-employment among non-Hispanic whites, blacks, Hispanics, and Asians in the United States, separately for men and women. The results show that, after controlling for individual-level characteristics, metropolitan labor-market characteristics-including macroeconomic conditions, overall business structure, ethnic composition, and residential segregation-significantly influence self-employment patterns across ethnic and gender groups.

This paper discusses the problem of family homelessness in Cuyahoga County, and provides baseline estimates of risk and shelter use. The issue was addressed using a two-pronged approach. The first approach used data from a large, representative sample of persons living in the county to estimate how many people below the poverty level live in doubled up housing situations. Given that many people who become homeless live in doubled up housing situations prior to becoming homeless, this estimate was intended to provide a baseline estimate of possible risk of homelessnessamong the countys poor population. The second approach was to examine a much smaller data set, containing information on persons actually using residential homeless services. Data were provided by the Cuyahoga County Office of Homeless Services as part of a nationwide attempt to document and count the numbers of sheltered homeless persons in the United States. This analysis detailed the numbers of persons living in families in the county who used emergency shelter, transitional housing, and permanent supportive housing facilities.

The role that source country characteristics has in determining the labor market performance of immigrants has long been explored by economists. For example, Borjas J. Borjas 1987 models the migration decision as determined by expected di_erence in the immigrant's position in the earnings distribution in the host and source countries. Deborah A. Cobb-Clark 1993 extends Bor- jas' model to immigrant women. Similarly, other studies explore how culture or traditional gender roles in the source country persist across borders and inuence the labor market outcomes of immigrant women in the U.S. For ex-ample, Heather Antecol 2001, 2000 and Francine D. Blau, Lawrence M. Kahn, and Kerry L. Papps 2008 _nd a positive relationship between source country characteristics and the labor market outcomes of immigrant women in the U.S. However, absent from the existing literature is an examination of how changes over time in a source country's characteristics are associated with changes in the labor market outcomes of immigrants from that source country.

The dissertation examines the trans-Pacific connections generated between China, Canada, and the United States through overseas Chinese schools in North America. It uses these learning institutions as a lens to investigate intergenerational differences and relationships, issues of nationalism, and changing gender roles in both China and North America during the early twentieth century.

We analyze the gender wage gaps among several countries that are members of the Organisation for Economic Co-operation and Development. Immigrants from countries where the source country gender wage gap has increased exhibit a decrease in the gender wage gap in the U.S. On the other hand, for immigrants from countries where the source country gender wage gap has decreased, the gender wage gap in the U.S. has increased. Our main hypothesis predicts that increases in the gender wage gap in the source country, where women are worse off relative to men, will generate incentives for high-ability women to emigrate. This in turn will widen the source country wage gap, but narrow the gender wage gap among immigrants from that country. This paper explores how changes in the source country labor market affect the observed distribution of earnings among women who migrate to the U.S. relative to their male counterparts.

Affirmative action in the United States has been a hotly contested and debated policy since Lyndon B. Johnson signed executive order 11246. The effects that affirmative action policy has had on the eradication of discrimination in the labor market are ambiguous. The purpose of my study is to analyze the potential negative effects affirmative action has on the wage gap and minority workers. The studies goal is to decide whether the correct tools are being employed to eliminate the wage gap between white males and minorities. I find that affirmative action policy has succeeded in closing the wage gap but not through the intended consequences of the policy. The emphasis on erasing discrimination through numerical yards has changed the mixture of the labor market but not attacked the obstructions for minorities in the labor market. The implications of my study suggest that discrimination against minorities is overstated in that human capital variations account for much of the wage gap. The study suggests that education is the key to eliminating the wage gap.

The sectoral composition of US economy has shifted dramatically in the recent decades. At the same time, knowledge and information capital has become increasingly important in modern production process. This paper argues that a ready explanation for the recent sectoral structural change lies in the di§erence of intangible capital accumulation across sectors. In the two-sector model of the paper, as the importance of intangible capital increases, labor is shifted from direct goods production to creating sector-speciÖc intangible capital. In the process, the real output and employment shares of the high-intangible sector increase. The model generates sectoral composition change and labor productivity trend that reasonably match the data. It also shows that conventional labor productivity calculation understates the "true" productivity in sectoral goods production. The underestimation is greater for the growing sector. The empirical regressions of the paper indicate a positive and signiÖcant association between intangible capital investment intensity and Örmsí future output and employment growth. The correlation is higher for Örms in the growing sector. At the industry level, controlling for industry human capital intensity, physical capital intensity and IT investment level, intangible capital intensity is positively correlated with future industry real output and employment share growth. These Öndings are consistent with the implications of the model. The paper also presents evidence suggesting that most growing service industries are intangible capital intensive. Thus the theory developed here can also help to reconcile the expansion of the service sector and the seemingly low productivity of the sector.