Does increasing parents' schooling raise the schooling of the next generation? Evidence based on conditional second moments

This paper investigates the degree of intergenerational transmission ofeducation for individuals from the National Longitudinal Survey of Youth1979. Rather than identifying the causal effect of parental education viainstrumental variables we exploit the feature of the transmissionmechanism responsible for its endogeneity. More explicitly, we assume theintergenerational transfer of unobserved ability is invariant to the economicenvironment. This, combined with the heteroskedasticity resulting from theinteraction of unobserved ability with socioeconomic factors, identifies thiscausal effect. We conclude the observed intergenerational educationalcorrelation reflects both a causal parental educational effect and a transferof unobserved ability.Intergenerational mobility, endogeneity, conditional correlation

A Parametric Control Function Approach to Estimating the Returns to Schooling in the Absence of Exclusion Restrictions: An Application to the NLSY

We estimate the return to education using a sample drawn from the National Longitudinal Survey of Youth 1979 (NLSY79). Rather than accounting for the endogeneity of schooling through the use of instrumental variables we employ a parametric version of the Klein and Vella (2006a) estimator. This estimator bypasses the need for instruments by exploiting features of the conditional second moments of the errors. As the Klein and Vella (2006a) procedure is semi-parametric it is computationally demanding. We illustrate how to greatly reduce the required computation by parameterizing the second moments. Accounting for endogeneity increases the estimate of the return to education by 5 percentage points, from 7.6% to 12.7%.return to education, heteroskedasticity, endogeneity

Does Increasing Parents' Schooling Raise the Schooling of the Next Generation? Evidence Based on Conditional Second Moments

This paper investigates the degree of intergenerational transmission of education for individuals from the National Longitudinal Survey of Youth 1979. Rather than identifying the causal effect of parental education via instrumental variables we exploit the feature of the transmission mechanism responsible for its endogeneity. More explicitly, we assume the intergenerational transfer of unobserved ability is invariant to the economic environment. This, combined with the heteroskedasticity resulting from the interaction of unobserved ability with socioeconomic factors, identifies this causal effect. We conclude the observed intergenerational educational correlation reflects both a causal parental educational effect and a transfer of unobserved ability.intergenerational mobility, endogeneity, conditional correlation

Subjective Health Assessments and Active Labor Market Participation of Older Men: Evidence from a Semiparametric Binary Choice Model with Nonadditive Correlated Individualspecific Effects

We use panel data from the US Health and Retirement Study 1992-2002 to estimate the effect of self-assessed health limitations on active labor market participation of men around retirement age. Self-assessments of health and functioning typically introduce an endogeneity bias when studying the effects of health on labor market participation. This results from justification bias, reflecting an individual’s tendency to provide answers which "justify" his labor market activity, and individual-specific heterogeneity in providing subjective evaluations. We address both concerns. We propose a semiparametric binary choice procedure which incorporates potentially nonadditive correlated individual-specific effects. Our estimation strategy identifies and estimates the average partial effects of health and functioning on labor market participation. The results indicate that poor health and functioning play a major role in the labor market exit decisions of older men.

Waggle dance distances as integrative indicators of seasonal foraging challenges

Even as demand for their services increases, honey bees (Apis mellifera) and other pollinating insects continue to decline in Europe and North America. Honey bees face many challenges, including an issue generally affecting wildlife: landscape changes have reduced flower-rich areas. One way to help is therefore to supplement with flowers, but when would this be most beneficial? We use the waggle dance, a unique behaviour in which a successful forager communicates to nestmates the location of visited flowers, to make a 2-year survey of food availability. We “eavesdropped” on 5097 dances to track seasonal changes in foraging, as indicated by the distance to which the bees as economic foragers will recruit, over a representative rural-urban landscape. In year 3, we determined nectar sugar concentration. We found that mean foraging distance/area significantly increase from springs (493 m, 0.8 km2) to summers (2156 m, 15.2 km2), even though nectar is not better quality, before decreasing in autumns (1275 m, 5.1 km2). As bees will not forage at long distances unnecessarily, this suggests summer is the most challenging season, with bees utilizing an area 22 and 6 times greater than spring or autumn. Our study demonstrates that dancing bees as indicators can provide information relevant to helping them, and, in particular, can show the months when additional forage would be most valuable

HUD student work-study program

Issued as monthly report [1]-15/16 (formerly E-17-502

The influence of the English Gothic romance on the novels of Charles Brockden Brown

This item was digitized by the Internet Archive. Thesis (M.A.)--Boston Universityhttps://archive.org/details/theinfluenceofen00dic

Seasonal reproduction in a fluctuating energy environment: Insolation-driven synchronized broadcast spawning in corals

*Background/Question/Methods:* Colonies of spawning corals reproduce in mass-spawning events, in which polyps within each colony release sperm and eggs for fertilization in the water column, with fertilization occurring only between gametes from different colonies. Participating colonies synchronize their gamete release to a window of a few hours once a year (for the species Acropora digitifera we study experimentally). This remarkable synchrony is essential for successful coral reproduction and thus, maintenance of the coral reef ecosystem that is currently under threat from local and global environmental effects such as pollution, global warming and ocean acidification. The mechanisms determining this tight synchrony in reproduction are not well understood, although several influences have been hypothesized and studied including lunar phase, solar insolation, and influences of temperature and tides. Moreover, most corals are in a symbiotic relationship with photosynthetic algae (Symbiodinium spp.) that live within the host tissue. Experiments supported by detailed bioenergetic modeling of the coral-algae symbiosis have shown that corals receive >90% of their energy needs from these symbionts. We develop a bioenergetic integrate-and-fire model in order to investigate whether annual insolation rhythms can entrain the gametogenetic cycles that produce mature gametes to the appropriate spawning season, since photosynthate is their primary source of energy. We solve the integrate-and-fire bioenergetic model numerically using the Fokker-Planck equation and use analytical tools such as rotation number to study entrainment.

*Results/Conclusions:* In the presence of short-term fluctuations in the energy input, our model shows that a feedback regulatory mechanism is required to achieve coherence of spawning times to within one lunar cycle, in order for subsequent cues such as lunar and diurnal light cycles to unambiguously determine the “correct” night of spawning. Entrainment to the annual insolation cycle is by itself not sufficient to produce the observed coherence in spawning. The feedback mechanism can also provide robustness against population heterogeneity due to genetic and environmental effects. We also discuss how such bioenergetic, stochastic, integrate-and-fire models are also more generally applicable: for example to aquatic insect emergence, synchrony in cell division and masting in trees