RESUMO
Calculations are reported on the rotation-vibration energy levels of the arsine molecule with associated transition intensities. A potential energy surface (PES) obtained from ab initio electronic structure calculations is refined to experimental data, and the resulting energy levels display sub-wavenumber accuracy for all reliably known J = 0 term values under 6500 cm-1. After a small empirical adjustment of the band centres, our calculated (J = 1-6) rovibrational states reproduce 578 experimentally derived energies with a root-mean-square error of 0.122 cm-1. Absolute line intensities are computed using the refined PES and a new dipole moment surface (DMS) for transitions between states with energies up to 10 500 cm-1 and rotational quantum number J = 30. The computed DMS reproduces experimental line intensities to within 10% uncertainty for the ν1 and ν3 bands. Furthermore, our calculated absorption cross-sections display good agreement with the main absorption features recorded in the Pacific Northwest National Laboratory (PNNL) for the complete range of 600-6500 cm-1.
RESUMO
BACKGROUND: Heavy menstrual bleeding is a leading cause of copper intrauterine device discontinuation. Thus, girls and women with heavy baseline menstrual bleeding may be at increased risk for early copper intrauterine device discontinuation. OBJECTIVE: Our objective was to assess if there was an association between baseline menstrual bleeding pattern prior to intrauterine device insertion and discontinuation rate at 12 months among study participants who chose copper intrauterine device at baseline. STUDY DESIGN: We performed a secondary analysis of the Contraceptive CHOICE Project, a prospective observational cohort study of 9256 girls and women offered no-cost contraception for 2-3 years. Included in our study were participants who chose copper intrauterine device for contraception and for whom method continuation data at 12 months were available. Prior to contraception initiation, participants were asked to qualify their menstrual bleeding over the past year as: light, moderate, moderately heavy, or heavy. Light bleeding corresponded to using ≤10 pads/tampons per period. Moderate, moderately heavy, and heavy bleeding corresponded to 11-20 pads/tampons, 21-30 pads/tampons, and >30 pads/tampons per period, respectively. Subjects were then categorized into either a "heavy" baseline group (those reporting moderately heavy or heavy bleeding at baseline), or a "not heavy" group (those reporting light or moderate bleeding). The 12-month continuation rate for each group was then calculated using Kaplan-Meier survival function, and hazard ratio for risk of discontinuation was evaluated using a Cox proportional hazard model to determine if moderately heavy or heavy bleeding at baseline was associated with early discontinuation. RESULTS: Of the 918 girls and women meeting the inclusion criteria for this analysis, 165 were in the heavy baseline bleeding group, while 753 were in the not heavy bleeding group. The 12-month continuation rates for groups were similar: 80.2% (heavy) and 85.0% (not heavy; P = .24). Patients reporting either moderately heavy or heavy baseline bleeding were not at increased risk for early discontinuation of copper intrauterine device (hazard ratio, 1.21; 95% confidence interval, 0.88-1.66). Our sample size provided >90% power to detect a clinically important difference of 15% (assuming 20% discontinuation rate in not heavy bleeding group and a 35% discontinuation rate in the heavy bleeding group). CONCLUSION: We did not find that girls and women who reported baseline moderately heavy or heavy menstrual bleeding were at increased risk for early discontinuation. Thus, we do not believe that girls and women with heavy menstrual bleeding should be discouraged from using this safe and highly effective form of contraception.
