Feature Selection of Post-Graduation Income of College Students in the United States

This study investigated the most important attributes of the 6-year post-graduation income of college graduates who used financial aid during their time at college in the United States. The latest data released by the United States Department of Education was used. Specifically, 1,429 cohorts of graduates from three years (2001, 2003, and 2005) were included in the data analysis. Three attribute selection methods, including filter methods, forward selection, and Genetic Algorithm, were applied to the attribute selection from 30 relevant attributes. Five groups of machine learning algorithms were applied to the dataset for classification using the best selected attribute subsets. Based on our findings, we discuss the role of neighborhood professional degree attainment, parental income, SAT scores, and family college education in post-graduation incomes and the implications for social stratification.Comment: 14 pages, 6 tables, 3 figure

Parametric sensitivity and uncertainty analysis of dimethylsulfide oxidation in the remote marine boundary layer

International audienceA study of the current significant uncertainties in dimethylsulfide (DMS) gas-phase chemistry provides insight into additional research needed to decrease these uncertainties. The DMS oxidation cycle in the remote marine boundary layer is simulated using a diurnally-varying box model with 56 uncertain chemical and physical parameters. Two analytical methods (direct integration and probabilistic collocation) are used to determine the most influential parameters (sensitivity analysis) and sources of uncertainty (uncertainty analysis) affecting the concentrations of DMS, SO2, methanesulfonic acid (MSA), and H2SO4. The key parameters identified by the sensitivity analysis are associated with DMS emissions, mixing in to and out of the boundary layer, heterogeneous removal of soluble sulfur-containing compounds, and the DMS+OH addition and abstraction reactions. MSA and H2SO4 are also sensitive to the rate constants of numerous other reactions, which limits the effectiveness of mechanism reduction techniques. Propagating the parameter uncertainties through the model leads to concentrations that are uncertain by factors of 1.8 to 3.0. The main sources of uncertainty are from DMS emissions and heterogeneous scavenging. Uncertain chemical rate constants, however, collectively account for up to 50?60% of the net uncertainties in MSA and H2SO4. The concentration uncertainties are also calculated at different temperatures, where they vary mainly due to temperature-dependent chemistry. With changing temperature, the uncertainties of DMS and SO2 remain steady, while the uncertainties of MSA and H2SO4 vary by factors of 2 to 4

Revisiting the effect of external fields in Axelrod's model of social dynamics

The study of the effects of spatially uniform fields on the steady-state properties of Axelrod's model has yielded plenty of controversial results. Here we re-examine the impact of this type of field for a selection of parameters such that the field-free steady state of the model is heterogeneous or multicultural. Analyses of both one and two-dimensional versions of Axelrod's model indicate that, contrary to previous claims in the literature, the steady state remains heterogeneous regardless of the value of the field strength. Turning on the field leads to a discontinuous decrease on the number of cultural domains, which we argue is due to the instability of zero-field heterogeneous absorbing configurations. We find, however, that spatially nonuniform fields that implement a consensus rule among the neighborhood of the agents enforces homogenization. Although the overall effects of the fields are essentially the same irrespective of the dimensionality of the model, we argue that the dimensionality has a significant impact on the stability of the field-free homogeneous steady state

The vascularity of the kidney as influenced by sensory impulses

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Chiral perturbation theory for electroweak reactions on deuterium

I summarize two recent applications of chiral perturbation theory to electromagnetic reactions on deuterium: elastic electron-deuteron scattering, and Compton scattering on deuterium. Both calculations have now been carried out to three orders in the chiral expansion. The expansion shows good convergence and is able to reproduce data for q < 600 MeV in e-d and for omega=55-95 MeV in gamma-d. These results demonstrate that ChiPT can be used to reliably compute operators and wave functions for low-momentum-transfer reactions in light nuclear systems.Comment: 10 pages, 6 figures. Write-up of invited talk at INT Workshop on "Nuclear Forces and the Quantum Many-Body Problem", October 4-8, 200