3,435 research outputs found

    The Influence of Contraception, Abortion, and Natural Family Planning on Divorce Rates as Found in the 2006–2010 National Survey of Family Growth

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    The purpose of this study was to determine the influence of contraception, abortion, and natural family planning (NFP) on divorce rates of US women of reproductive age. The variables of importance of religion and frequency of church attendance were also included in the analysis. The study involved 5,530 reproductive age women in the (2006–2010) National Survey of Family Growth who indicate that they were ever married. Among the women who ever used NFP only 9.6 percent were currently divorced compared with the 14.4 percent who were currently divorced among the women who never used NFP (x2 = 5.34, P \u3c 0.21). Odds ratio analysis indicated that ever having an abortion, sterilization, and/or methods of contraception increased the likelihood of divorce – up to two times. Frequency of church attendance decreased the risk of divorce. Although there is less divorce among NFP users the reason might be due to their religiosity. Lay summary: Providers of natural family planning (NFP) frequently mention that couples who practice NFP have fewer divorces compared to couples who use contraception. Evidence for this comment is weak. This study utilized a large data set of 5,530 reproductive age women to determine the influence that contraception, sterilization, abortion, and NFP has on divorce rates. Among the women participants who ever used NFP only 9.6 percent were currently divorced compared with the 14.4 percent who used methods of contraception, sterilization or abortion as a family planning method. Frequency of church attendance also reduced the likelihood of divorce

    Promoting Natural Family Planning

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    Confirmation of Eclipses in KPD 0422+5421, A Binary Containing a White Dwarf and a Subdwarf B Star

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    We report additional photometric CCD observations of KPD 0422+5421, a binary with an orbital period of 2.16 hours which contains a subdwarf B star (sdB) and a white dwarf. There are two main results of this work. First, the light curve of KPD 0422+5421 contains two distinct periodic signals, the 2.16 hour ellipsoidal modulation discovered by Koen, Orosz, & Wade (1998) and an additional modulation at 7.8 hours. This 7.8 hour modulation is clearly not sinusoidal: the rise time is about 0.25 in phase, whereas the decay time is 0.75 in phase. Its amplitude is roughly half of the amplitude of the ellipsoidal modulation. Second, after the 7.8 hour modulation is removed, the light curve folded on the orbital period clearly shows the signature of the transit of the white dwarf across the face of the sdB star and the signature of the occultation of the white dwarf by the sdB star. We used the Wilson-Devinney code to model the light curve to obtain the inclination, the mass ratio, and the Omega potentials, and a Monte Carlo code to compute confidence limits on interesting system parameters. We find component masses of M_sdB = 0.36 +/- 0.16 solar masses and M_WD = 0.47 +/- 0.16 solar masses (M_total = 0.86 +/- 0.35 solar masses, 68 per cent confidence limits). If we impose an additional constraint and require the computed mass and radius of the white dwarf to be consistent with a theoretical mass-radius relation, we find M_sdB = 0.511 +0.047 -0.050 solar masses and M_WD = 0.526 +0.033 -0.030 solar masses (68 per cent confidence limits). In this case the total mass of the system is less than 1.4 solar masses at the 99.99 per cent confidence level. We briefly discuss possible interpretations of the 7.8 hour modulation and the importance of KPD 0422+5421 as a member of a rare class of evolved binaries.Comment: 11 pages, 7 figures, to appear in MNRAS, LaTeX, uses mn.st

    Pilot Evaluation of an Internet-based Natural Family Planning Education and Service Program

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    Objective: To evaluate the efficacy, knowledge of fertility, and acceptability of a web-based natural family planning (NFP) education and service program. Design: A 6-month repeated measure longitudinal evaluation pilot study. Setting: A university based online website. Participants: The website was piloted with 468 volunteer women seeking NFP services. Of these participants, 222 used the automatic online fertility charting system to avoid pregnancy. The 222 charting participants had a mean age of 29.9 years (SD=5.6), 2.2 children (SD=1.9), 37% were postpartum, and 47% had regular menstrual cycle lengths. Intervention: Nurse-managed web-based NFP education and service program. Outcomes: Pregnancies were confirmed by an online self-assessed pregnancy evaluation form. A 10-item fertility quiz and 10-item acceptability survey was administered online. Results: Among the 222 users avoiding pregnancy, at 6 months of use, there were two correct-use unintended pregnancies that provided a pregnancy rate of 2% and seven total unintended pregnancies providing a typical use pregnancy rate of 7%. Mean knowledge of fertility increased significantly from time of registration (8.96, SD=1.10) to 1 month of use (9.46, SD=.10), t=4.60, pSD=8.98) to 6 months of use (48.4; SD=8.77). Conclusion: The nurse-managed online NFP system seems to provide adequate knowledge of fertility and help participants meet pregnancy intentions. Acceptability of such a system of NFP is still in question

    KPD 0422+5421: A New Short Period Subdwarf B/White Dwarf Binary

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    The sdB star KPD 0422+5421 was discovered to be a single-lined spectroscopic binary with a period of P=0.0901795 +/- (3\times 10^{-7}) days (2 hours, 10 minutes). The U and B light curves display an ellipsoidal modulation with amplitudes of about 0.02 magnitudes. The sdB star contributes nearly all of the observed flux. This and the absence of any reflection effect suggest that the unseen companion star is small (i.e. R_comp ~ 0.01 solar radii) and therefore degenerate. We modeled the U and B light curves and derived i = 78.05 +/- 0.50 degrees and a mass ratio of q = M_comp/M_sdB = 0.87 +/- 0.15. The sdB star fills 69% of its Roche lobe. These quantities may be combined with the mass function of the companion (f(M) = 0.126 +/- 0.028 solar masses) to derive M_sdB = 0.72 +/- 0.26 solar masses and M_comp = 0.62 +/- 0.18 solar masses. We used model spectra to derive the effective temperature, surface gravity, and helium abundance of the sdB star. We found T_eff = 25,000 +/- 1500K, log g = 5.4 +/- 0.1, and [He/H] = -1.0. With a period of 2 hours and 10 minutes, KPD 0422+5421 has one of the shortest known orbital periods of a detached binary. This system is also one of only a few known binaries which contain a subdwarf B star and a white dwarf. Thus KPD 0422+5421 represents a relatively unobserved, and short-lived, stage of binary star evolution.Comment: 9 pages, 8 figures, to appear in MNRAS, LaTeX, uses mn.st

    Territorial Invasion and Aggression.

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    Complex Remanence vs. Simple Persistence: Are Hysteresis and Unit-Root Processes observationally equivalent?

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    The hysteresis terminology has mainly been used in two fields of economics, unemplyment and international trade, with a different meaning however, involving either linear autoregressive macro behaviour or non- linear heterogenous mico behaviour. There may nonetheless be observational equivalence between the 'persistence' characterising unit- root processes and the 'remanence' created by the aggregation of non- linear dynamics. Stochastic simulations are employed to analyse the properties of the output of an hysteretic system, subject to white noise and random walk inputs. Non-linear hysteretic systems are found to generate a sizeable proportion - two-thirds - of stationary output from stationary input, and to possibly generate an output cointegrated with the corresponding input. Such processes therefore appear significantly different from an integrated process. This stresses the specific relevance of a non-linear approach to hysteresis.hysteresis, non-linearity, aggregation, heterogeneity, experimental economics
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