Correlates of Household Seismic Hazard Adjustment Adoption

This study examined the relationships of self-reported adoption of 12 seismic hazard adjustments (pre-impact actions to reduce danger to persons and property) with respondents' demographic characteristics, perceived risk, perceived hazard knowledge, perceived protection responsibility, and perceived attributes of the hazard adjustments. Consistent with theoretical predictions, perceived attributes of the hazard adjustments differentiated among the adjustments and had stronger correlations with adoption than any of the other predictors. These results identify the adjustments and attributes that emergency managers should address to have the greatest impact on improving household adjustment to earthquake hazard.     

Biodiversity conservation implications of landscape change in an urbanizing desert of Southwestern Peru

Internal migration from the Peruvian highlands and rural areas has burdened urban areas with rapid growth. Urban expansion is threatening the desert habitat and unique vegetation communities surrounding Arequipa, one of Peru's largest cities. A 511 ha tract contiguous to the city of Arequipa has been informally designated an ecological park. Analysis of Landsat satellite imagery over a 16-year interval indicates that urban expansion is occurring in the direction of the park. The land use/land cover change analysis revealed other landscape patterns and processes, such as agricultural expansion, which are relevant to the study area. These dynamics, plus principles of landscape ecology, suggest that the park's size and shape may not be the most suitable. Conservation alternatives include the expansion of the park, the spatial connection to another nature reserve, or the design of co-management strategies. Given local historical events and the paucity of regional conservation efforts, social actors in Arequipa and in national governmental institutions will need to find practical ways to collaborate.     

Economic development and fertility change in Mexico, 1950–1970

This paper is an attempt to isolate the determinants of fertility in Mexico. Of the variables included, two are significant in accounting for differences in the level of completed fertility in the 32 "states" in 1970. They are the share of the labor force in agriculture, which is directly related to fertility, and the percentage of the population speaking an indigenous language, which shows an inverse relationship.The most important factors acting to reduce total fertility rates over time are increases in life expectancy and declines in the share of the labor force in agriculture. However, based on the estimated linear relationship, these two variables by themselves are not adequate to achieve a rapid decline in fertility in the future.     

Generalized Method of Moments With Many Weak Moment Conditions

Using many moment conditions can improve efficiency but makes the usual generalized method of moments (GMM) inferences inaccurate. Two‐step GMM is biased. Generalized empirical likelihood (GEL) has smaller bias, but the usual standard errors are too small in instrumental variable settings. In this paper we give a new variance estimator for GEL that addresses this problem. It is consistent under the usual asymptotics and, under many weak moment asymptotics, is larger than usual and is consistent. We also show that the Kleibergen (2005) Lagrange multiplier and conditional likelihood ratio statistics are valid under many weak moments. In addition, we introduce a jackknife GMM estimator, but find that GEL is asymptotically more efficient under many weak moments. In Monte Carlo examples we find that t‐statistics based on the new variance estimator have nearly correct size in a wide range of cases.     

Going Back Part-time: Family Leave Legislation and Women’s Return to Work

Using a multinomial logit model with data from the Survey of Income and Program Participation, this paper tests whether the implementation of the Family and Medical Leave Act (FMLA) is associated with an increase in return to work at part-time status among first-time mothers working full-time during their pregnancy. I find a statistically significant trend of increasingly higher odds of returning to work at part-time status relative to return at full-time status, beginning in 1993 (the year in which the FMLA is implemented). Furthermore, an additional week of either state or federal leave is significantly associated with a higher odds of return at part-time status. This article provides evidence that job protection and leave legislation may help facilitate higher levels of labor force participation among women with small children, through more flexible work arrangements.     

Parameter estimation in a highly non-linear model using simultaneous perturbation stochastic approximation

Often it is necessary to estimate the parameters of a model or unknown system. Various techniques exist to accomplish this task, including Kalman and Wiener filtering, least-mean-square (LMS) algorithms, and the Levenberg-Marquardt(L-M) algorithm. These techniques require an analytic form of the gradient of the function of the parameters to be estimated. A key feature of the simultaneous perturbation stochastic approximation (SPSA) method is that it is a gradient-free optimization technique (Spall; 1992,1998a,b, 1999). In the current problem, the function of parameters to be identified is highly non-linear and of sufficient difficulty that obtaining an analytic form of the gradient is impractical. Therefore, in this paper the

performance of the SPSA algorithm will be examined in terms of parameter selection, data requirements, and convergence performance on this non-linear problem. Results will be reported on both a first-order "standard" implementation of SPSA and on a second-order version of SPSA that tends to enhance convergence.     

A new approach to assessing ethical conduct in scientific work

The intent of the current article is to describe the development of a new approach to the study of ethical conduct in scientific research settings. The approach presented in this article has two main components. The first component entails the development of a taxonomy of ethical events as they occur across a broad range of scientific disciplines. The second involves the identification of proximate criteria that will allow systematic and objective evaluation of ethical behaviors through low-fidelity performance simulations. Two proposed measures based on the new approach are intended to identify and measure variations in the scientific environment that might predispose certain individuals to make unethical decisions.     

The acuity of echolocation: Spatial resolution in the sighted compared to expert performance

Compared with the echolocation performance of a blind expert, sighted novices rapidly learned size and position discrimination with surprising precision. We use a novel task to characterize the population distribution of echolocation skill in the sighted and report the highest known human echolocation acuity in our expert subject.     

The effect of earthworms on roadway-derived Zn deposited as a surface layer in storm water retention basin soils

Increased urban development, including an increase in impervious surfaces has the potential to alter the biogeochemistry of surface systems due to storm water runoff contaminated with potentially toxic trace metals (e.g. Zn, Cu and Pb). A major source for urban metals is dust that accumulates on roadways. This roadway dust is derived from vehicle wear sources and tends to be enriched in trace metals such as Pb, Zn, Cu, Cd, Ni and Cr. This continuous source is then being transported via storm water runoff to receiving systems, such as storm water retention systems, which become important focusing environments for trace metal deposition. The fate of these roadway derived metals and their bioavailability once deposited in these urban ecosystems is not well understood. In this investigation we tested the hypothesis that the distribution and form of surface deposited roadway-derived Zn is a function of earthworm processes and is species dependent. The results of this investigation indicate that roadway dust derived Zn deposited as a surface layer on urban soils is readily removed from the surface in less than 30 days whether earthworms are present or not. However, after 90 days, the presence of earthworms and the life habit of the earthworm species present was found to have a significant impact on the physical and chemical cycling of roadway derived trace metals in storm water retention basin soils.     

Healthcare-Related Financial Burden Among Families in the U.S.: The Role of Childhood Activity Limitations and Income

This study examined the impact of childhood activity limitations on family financial burden in the U.S. We used ten complete panels (1996–2006) of the Medical Expenditure Panel Survey (MEPS) to evaluate the burden of out-of-pocket healthcare expenditures for 17,857 families with children aged 0–17 years. Multivariate generalized linear models were used to examine the relationship between childhood activity limitation status and both absolute and relative financial burden. Families of children with limitations had higher absolute out-of-pocket healthcare expenditures than families of children without limitations ($594.36 higher; p < 0.05), and were 54% more likely to experience relative burden (p < 0.05). Substantial socioeconomic disparities in financial burden were observed. Policies are needed to enable these families to access appropriate and affordable healthcare services.