Urban and agricultural soils: conflicts and trade-offs in the optimization of ecosystem services

On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.     

Jensen's Inequality for General Location Parameter

A wide class of location parameters is shown to satisfy Jensen's inequality. When the expectation EX exists and l is a convex function, Jensen's inequality states that El(x) ≥ l(EX). It is shown that for μ, a properly defined location parameter, μ(l(x)) μ l(μ(x)).     

Two Pitfalls of Using Standard Regression Diagnostics When Both X and Y Have Measurement Error

Modern exploratory data analysis produces models that are not based on physical theory but that are consistent with pictures of the data. When both X and Y have error this can be risky, because important features are hidden. Two examples are given that show that systematic model departures and heteroscedasticity may not be detectable with standard regression diagnostics.     

EDUCATIONAL AND WORK STRATEGIES FROM ADOLESCENCE TO EARLY ADULTHOOD: CONSEQUENCES FOR EDUCATIONAL ATTAINMENT

Whereas sociologists have long recognized that adolescence marks the start of the socioeconomic career, the importance of this period has been attributed to school performance, aspirations, and significant others' influence that support educational attainment to a greater or lesser degree. The underlying premise of this study is that adolescent work is an expression of instrumental action with consequences for socioeconomic attainment. Using data from the Youth Development Study, we find that part-time work during high school is linked with patterns of schooling and working that persist during the succeeding years and are more or less conducive to the receipt of a BA/BS degree. Moderate work coupled with school appears to especially facilitate the educational attainment of low promise youth.     

The economics of child care and public policy

Child care denotes any arrangement used by a working parent for care of a child, including self-care. This article is concerned with the factors that influence the demand for market modes of child care by two parent families with working mothers. A unique aspect of the study is that it is able to assess the impact of a child care subsidy program. An implication of the analysis is that the demand for market care is price elastic and is therefore susceptible to considerable change through programs of increased subsidization.     

Is Adolescent Employment Still a Risk Factor for High School Dropout?

Past cohorts of teenagers who spent long hours in jobs were more likely to drop out of high school than those who worked moderate hours or did not work at all. This article examines the association between employment intensity and dropout among adolescents in the High School Longitudinal Study of 2009 who traversed high school during a time of decreased prevalence of both employment and dropout relative to earlier cohorts. Analyses reveal that a relatively small percentage of teenagers nowadays are characterized as either intensive workers or dropouts (around 11% each). Yet, despite declines in intensive employment and dropout, disadvantaged youth remain overrepresented in both groups, and intensive work is still a risk factor for poor grades and dropout.