WOMEN’S LABOR FORCE PARTICIPATION AND THE DYNAMICS OF TRADITION

We present a model in which the social norms regarding women’s labor force participation (LFP) differ from the norms concerning men’s. Assuming that these norms depend on past rates of women LFP creates a gradual increase in women LFP.

The Baby Boom and World War II: A Macroeconomic Analysis

We argue that one major cause of the U.S. postwar baby boom was the rise in female labor supply during WorldWar II. We develop a quantitative dynamic general equilibrium model with endogenous fertility and female labor force participation decisions. We use the model to assess the impact of the war on female labor supply and fertility in the decades following the war. For the war generation of women, the high demand for female labor brought about by mobilization leads to an increase in labor supply that persists after the war. As a result, younger women who reach adulthood in the 1950s face increased labor market competition, which impels them to exit the labor market and start having children earlier. The effect is amplified by the rise in taxes necessary to pay down wartime government debt. In our calibrated model, the war generates a substantial baby boom followed by a baby bust.

The Baby Boom and World War II: The Role of Labor Market Experience

The past century has witnessed major changes in the economic choices of American women. Over the long term, there has been a marked trend towards lower fertility and higher female labor force participation. However, change did not occur in a uniform fashion: during the post-war Baby Boom, fertility rates increased substantially, until the long-term downward trend reestablished itself in the 1960s. Similarly, the labor market participation of younger women declined for a while during the same period. What can explain these reversals? In this paper, we propose a joint explanation for these changes through a single shock: the demand for female labor during World War II. Many of the women of the war generation continued to work after the war. We argue that this crowded out younger women from the labor market, who chose to have more children instead.

The Toroidal Obscuration of Active Galactic Nuclei

Observations give strong support for the unification scheme of active galactic nuclei. The scheme is premised on toroidal obscuration of the central engine by dusty clouds that are individually very optically thick. These lectures summarize the torus properties, describe the handling and implications of its clumpy nature and present speculations about its dynamic origin.Comment: To appear in proceedings of "Active Galactic Nuclei at the highest angular resolution: theory and observations", 2007 summer school, Torun, Polan

A Compact Representation of Drawing Movements with Sequences of Parabolic Primitives

Some studies suggest that complex arm movements in humans and monkeys may optimize several objective functions, while others claim that arm movements satisfy geometric constraints and are composed of elementary components. However, the ability to unify different constraints has remained an open question. The criterion for a maximally smooth (minimizing jerk) motion is satisfied for parabolic trajectories having constant equi-affine speed, which thus comply with the geometric constraint known as the two-thirds power law. Here we empirically test the hypothesis that parabolic segments provide a compact representation of spontaneous drawing movements. Monkey scribblings performed during a period of practice were recorded. Practiced hand paths could be approximated well by relatively long parabolic segments. Following practice, the orientations and spatial locations of the fitted parabolic segments could be drawn from only 2–4 clusters, and there was less discrepancy between the fitted parabolic segments and the executed paths. This enabled us to show that well-practiced spontaneous scribbling movements can be represented as sequences (“words”) of a small number of elementary parabolic primitives (“letters”). A movement primitive can be defined as a movement entity that cannot be intentionally stopped before its completion. We found that in a well-trained monkey a movement was usually decelerated after receiving a reward, but it stopped only after the completion of a sequence composed of several parabolic segments. Piece-wise parabolic segments can be generated by applying affine geometric transformations to a single parabolic template. Thus, complex movements might be constructed by applying sequences of suitable geometric transformations to a few templates. Our findings therefore suggest that the motor system aims at achieving more parsimonious internal representations through practice, that parabolas serve as geometric primitives and that non-Euclidean variables are employed in internal movement representations (due to the special role of parabolas in equi-affine geometry)

The Baby Boom and World War II: A Macroeconomic Analysis

We argue that one major cause of the U.S. postwar baby boom was the increased demand for female labor during World War II. We develop a quantitativendynamic general equilibrium model with endogenous fertility and female labor-force participation decisions. We use the model to assess the long-term implications of a one-time demand shock for female labor, such as the one experienced by American women during wartime mobilization. For the war generation, the shock leads to a persistent increase in female labor supply due to the accumulation of work experience. In contrast, youngernwomen who turn adult after the war face increased labor-market competition, which impels them to exit the labor market and start having children earlier. In our calibrated model, this general-equilibrium effect generates a substantial baby boom followed by a baby bust, as well as patterns for agespecific labor-force participation and fertility rates that are consistent withnU.S data

Women's lifetime labor supply and labor market experience

The pattern of joining the labor force only at an advanced stage of the life-cycle was widespread among American women in the 1960s and 1970s, but not since the 1980s. To explain this change we conduct a theoretical analysis of the interrelation between women's lifetime labor supply choices and the dynamic macroeconomic environment. In our model women choose the late-entry pattern only at early stages of the growth process when wages are sufficiently low and grow sufficiently rapidly. As the economy grows, this lifetime labor profile vanishes and women either join the labor force either early in life or not at all.Experience Labor Force Participation