Investigating the use of mastery-style online homework exercises in introductory algebra-based mechanics in a controlled clinical study

Homework in introductory physics represents an important part of a student’s learning experience; therefore, choosing the manner in which homework is presented merits investigation. We performed three rounds of clinical trials comparing the effects of mastery-style homework vs traditional-style homework with students in both algebra-based and calculus-based introductory mechanics. Results indicate a benefit from mastery-style over traditional-style homework, principally for weaker students who are less familiar with the material being covered and on questions that are nearer transfer to the study materials

Determination of the D-0 -> K- pi(+) pi(0) and D-0 -> K- pi(+) pi(+) pi(-) coherence factors and average strong-phase differences using quantum-correlated measurements

The first measurements of the coherence factors (R-K pi pi 0 and R-K3 pi) and the average strong-phase differences((delta(K pi pi 0)(D) and delta(K3 pi)(D))) for D-0 -> K- pi(+) pi(0) and D-0 -> K- pi(+) pi(+) pi(-) are presented. These parameters can be used to improve the determination of the unitarity triangle angle gamma in B- -> DK- decays, where D is a D-0 or (D) over bar (0) meson decaying to the same final state. The measurements are made using quantum-correlated, fully reconstructed D-0(D) over bar (0) pairs produced in e(+)e(-) collisions at the psi(3770) resonance. The measured values are: R-K pi pi 0 = 0.84 +/- 0.07, delta(K pi pi 0)(D) = (227(-17)(+14))degrees, R-K3 pi = 0.33(-0.23)(+0.20), and delta(K3 pi)(D) = (114(-23)(+26))degrees. These results indicate significant coherence in the decay D-0 -> K- pi(+) pi(0), whereas lower coherence is observed in the decay D-0 -> K- pi(+) pi(+) pi(-). The analysis also results in a small improvement in the knowledge of other D-meson parameters, in particular, the strong-phase difference for D-0 -> K- pi(+), delta(K pi)(D), and the mixing parameter y