Interpreting the evidence on life cycle skill formation

This paper presents economic models of child development that capture the essence of recent findings from the empirical literature on skill formation. The goal of this essay is to provide a theoretical framework for interpreting the evidence from a vast empirical literature, for guiding the next generation of empirical studies, and for formulating policy. Central to our analysis is the concept that childhood has more than one stage. We formalize the concepts of self-productivity and complementarity of human capital investments and use them to explain the evidence on skill formation. Together, they explain why skill begets skill through a multiplier process. Skill formation is a life cycle process. It starts in the womb and goes on throughout life. Families play a role in this process that is far more important than the role of schools. There are multiple skills and multiple abilities that are important for adult success. Abilities are both inherited and created, and the traditional debate about nature versus nurture is scientiÞcally obsolete. Human capital investment exhibits both self-productivity and complementarity. Skill attainment at one stage of the life cycle raises skill attainment at later stages of the life cycle (self-productivity). Early investment facilitates the productivity of later investment (complementarity). Early investments are not productive if they are not followed up by later investments (another aspect of complementarity). This complementarity explains why there is no equity-efficiency trade-off for early investment. The returns to investing early in the life cycle are high. Remediation of inadequate early investments is difficult and very costly as a consequence of both self-productivity and complementarity

Asteroseismic Theory of Rapidly Oscillating Ap Stars

This paper reviews some of the important advances made over the last decade concerning theory of roAp stars.Comment: 9 pages, 5 figure

Distributed River Basin Modeling for Analyzing Flood Mitigation Measures under Non-stationary Conditions

Flood frequency analysis is in the main component of flood risk management projects, influencing pre and post-flood activities. Apart from its importance and the intense research in the area, the available hydrological methods are not adequate, especially under non-stationary conitions caused by land cover or climate change. In this work a new hydrological model is proposed, with the goal of overcome the main weakness of the traditional methodologies. This research is composed by three main goals. First, the authors attend to add functionalities to an existing calibration-free hydrological model based on the scaling theory of floods. The goal is to provide a better representation of the rainfall-runoff processes that occur in a hillslope scale through the use of empirical models. This model constitutes an important tool for the evaluation of effects of land characteristic changes on flood intensity and frequency. The second goal is the development of a flood risk framework, with the aim of link hydrological criteria of flood intensity estimation (peak discharge) to criteria that measures flood impact (damages). This activity requires the development of flood maps and the quantification of flood damage. This research presents a simplified methodology for flood risk mapping that can be used for areas with very limited information about the river network. Annual expected damage was used as criteria to evaluate different land characteristics scenarios, being damage estimated by a simple model based on the city parcels structure value and water level-damage curves proposed by FEMA. The last goal is to develop a simplified case study to demonstrate the model applicability on flood risk management. A case study for Charlotte City, North Carolina was developed. The city has experienced an extensive urban growth since 1960 which has led to significant changes in city's risk and vulnerability to floods. The impacts of urbanization were evaluated using current land cover conditions and two extreme scenarios: pre-development and built-out. The effectiveness of non-punctual flood mitigation measures that are easily harmonized in the urban environment was also evaluated. The innovative aspect of this study is to present a new methodology for flood frequency analysis that does not require calibration and has the potential to be applied to any region in the world. By this framework a multiple scale analysis of flood peak and flood damage is obtained, prviding essential information for the implementation of an optimal flood risk management policy over different levels of governmental policies (local, regional and global)

Accessing the Acceleration of the Universe with Sunyaev-Zel'dovich and X-ray Data from Galaxy Clusters

By using exclusively the Sunyaev-Zel'dovich effect and X-ray surface brightness data from 25 galaxy clusters in the redshift range 0.023< z < 0.784 we access cosmic acceleration employing a kinematic description. Such result is fully independent on the validity of any metric gravity theory, the possible matter-energy contents filling the Universe, as well as on the SNe Ia Hubble diagram.Comment: 3 pages, 4 figures, To appear in the Proceedings of the Twelfth Marcel Grossmann Meeting on General Relativit