The Nonequivalence of High School Equivalents

This paper analyzes the causes and consequences of the growing proportion of high-school-certified persons who achieve that status by exam certification rather than through high school graduation. Exam-certified high school equivalents are statistically indistinguishable from high school dropouts. Both dropouts and exam-certified equivalents have comparably poor wages, earnings, hours of work, unemployment experiences and job tenure. This is so whether or not ability measures are used to control for differences. Whatever differences are found among exam-certified equivalents, high school dropouts and high school graduates are accounted for by their years of schooling completed. There is no cheap substitute for schooling. The only payoff to exam certification arises from its value in opening post-secondary schooling and training opportunities. However, exam-certified equivalents receive lower returns to most forms of post-secondary education and training. We also discuss the political economy of the recent rapid growth of exam certification. There has been growth in direct government subsidies to adult basic education programs that feature exam certification as an output. In addition, there has been growth in government subsidies to post-secondary schooling programs that require certification in order to qualify for benefits. These sources account for the rapid growth in the use of exam certification in the face of the low economic returns to it.

The Dynamics of Educational Attainment for Blacks, Hispanics, and Whites

This paper estimates a dynamic model of schooling attainment to investigate the sources of discrepancy by race and ethnicity in college attendance. When the returns to college education rose, college enrollment of whites responded much more quickly than that of minorities. Parental income is a strong predictor of this response. However, using NLSY data, we find that it is the long-run factors associated with parental background and income and not short-term credit constraints facing college students that account for the differential response by race and ethnicity to the new labor market for skilled labor. Policies aimed at improving these long-term factors are far more likely to be successful in eliminating college attendance differentials than are short-term tuition reduction policies.

Very-large-scale motions in rough-bed open-channel flow

Acknowledgements The study has been supported by two EPSRC/UK grants, ‘High-resolution numerical and experimental studies of turbulence-induced sediment erosion and near-bed transport’ (EP/G056404/1) and ‘Bed friction in rough-bed free-surface flows: a theoretical framework, roughness regimes, and quantification’ (EP/K041169/1). Discussions with I. Marusic and comments of three anonymous reviewers are greatly appreciated.Peer reviewedPublisher PD

Magnetic activity on AB Doradus: Temporal evolution of starspots and differential rotation from 1988 to 1994

Surface brightness maps for the young K0 dwarf AB Doradus are reconstructed from archival data sets for epochs spanning 1988 to 1994. By using the signal-to-noise enhancement technique of Least-Squares Deconvolution, our results show a greatly increased resolution of spot features than obtained in previously published surface brightness reconstructions. These images show that for the exception of epoch 1988.96, the starspot distributions are dominated by a long-lived polar cap, and short-lived low to high latitude features. The fragmented polar cap at epoch 1988.96 could indicate a change in the nature of the dynamo in the star. For the first time we measure differential rotation for epochs with sufficient phase coverage (1992.05, 1993.89, 1994.87). These measurements show variations on a timescale of at least one year, with the strongest surface differential rotation ever measured for AB Dor occurring in 1994.86. In conjunction with previous investigations, our results represent the first long-term analysis of the temporal evolution of differential rotation on active stars.Comment: accepted by MNRAS 18 pages 18 figure

Time-Resolved PIV And Pressure Measurements Of Oscillating And Pulsating Flow In A Diffuser

Separating oscillating and pulsating flows in an internal adverse pressure gradient geometry are studied experimentally. Simultaneous velocity-pressure measurements demonstrate that the minor losses associated with oscillating flow in an adverse pressure gradient geometry can be smaller or larger than for steady flow. Separation is found to begin high in the diffuser and propagate downward. Flows are able to remain attached further into the diffuser with larger Reynolds numbers, larger stroke lengths, and smaller diffuser angles. The extent of separation grows with Lo/h. The minor losses grow with increasing displacement amplitude in the range 10 \u3c Lo/h \u3c 40. Losses decrease with Re in the range of 38

Relationship Between Lower Body Strength, Countermovement Jump Height, and Optimal Drop Jump Drop Height

The purpose of this study was to understand the relationship between back squat one-repetition maximum relative to body mass (1RMrel), countermovement jump height (CMJH), and optimal drop height in drop jump (DHopt). Fifteen male participants with various sport backgrounds and training experience completed a one repetition maximum (1RM) back squat, maximum countermovement jump (CMJ), and drop jumps (DJ) from incrementally increasing drop heights to determine which drop height elicited the greatest jump height. The DHopt testing protocol was unique in that smaller increments were used to determine DHopt compared to what has been reported in literature previously. Pearson correlation coefficients revealed that DHopt had small (r=0.214) and moderate (r=0.464) relationships with 1RMrel and CMJH, respectively. A second analysis (n=13) was conducted after two participants (i.e. powerlifters) were identified as possibly being representative of a different population. The second analysis found that DHopt had strong relationships with 1RMrel (r=0.645) and CMJH (r=0.690). Results from this study seem to suggest that individuals with greater 1RMrel and CMJH tend to have a higher DHopt. However, this relationship may not be observed among all populations due to likely differences in sport background, genetics, and/or training experience