Superconducting transition of a two-dimensional Josephson junction array in weak magnetic fields

The superconducting transition of a two-dimensional (2D) Josephson junction array exposed to weak magnetic fields has been studied experimentally. Resistance measurements reveal a superconducting-resistive phase boundary in serious disagreement with the theoretical and numerical expectations. Critical scaling analyses of the $IV$ characteristics indicate contrary to the expectations that the superconducting-to-resistive transition in weak magnetic fields is associated with a melting transition of magnetic-field-induced vortices directly from a pinned-solid phase to a liquid phase. The expected depinning transition of vortices from a pinned-solid phase to an intermediate floating-solid phase was not observed. We discuss effects of the disorder-induced random pinning potential on phase transitions of vortices in a 2D Josephson junction array.Comment: 9 pages, 7 figures (EPS+JPG format), RevTeX

Study on Awareness of Preconception Care and Reproductive Health Behaviors in Pre-honeymooners

PURPOSE: The purpose of this study was 1) to examine levels of awareness on preconception care and pregnancy, and reproductive health promoting behavior among pre-honeymooners; and 2) to explore the relationship between awareness levels of preconception care and pregnancy, and reproductive health promoting behavior. METHODS: This study was a correlation design with a total of 134 participants (67 couples of pre-honeymooners). Data were collected with questionnaire. RESULTS: Mean score of self-perception of awareness of preconception care and pregnancy was 2.82 out of 4. Content awareness level was 6.83 out of 13, and reproductive health promoting behavior score was 3.02 out of 4, indicating low to mid-level. Women reported higher scores in all variables than those in men. Self-perception awareness and content awareness of care and pregnancy had a weak positive correlation (r=.18, p=.038). Reproductive health promoting behavior was positively related to self-perception awareness of care and pregnancy (r=.33, p<.001) and content awareness of care and pregnancy (r=.23, p=.008). CONCLUSION: Based on this results, a variety of nursing intervention strategies may need to promote reproductive health behavior such as raising awareness of the preconception care and pregnancy

A Structural Equation Modeling on Reproductive Health Promoting Behavior of Unmarried Women: Based on the Theory of Planned Behavior

PURPOSE: The purpose of this study was to construct and test a structural equation modeling on the reproductive health behavior of single women with sexual experiences. This study employed Ajzen's Theory of Planned Behavior (TPB). METHODS: The data were collected after receipt of consent from 250 single women with sexual experiences, and analyzed using SPSS 18.0 and AMOS 18.0. RESULTS: Model fit indices for the hypothetical model were suitable for the recommended level: x²=362.407, RMR=0.065, RMSEA=0.070, GFI=0.867. TLI=0.927, CFI=0.938, IFI=0.939, and x²/dF=2.237. Intention showed direct effect with the biggest effect being on reproductive health behavior. Attitude, subjective norm and perceived behavioral control were found to have a direct effect on intention. Among them, perceived behavioral control revealed the largest influence. CONCLUSION: This study suggests that the TPB is a suitable model in explaining the reproductive health behavior of single women with sexual experience. Strategic plans for educational and intervention programs should be aimed to encourage single women to engage in reproductive health behavior

Prevalence, Distribution, and Concomitance of Whole-Spine Ossification of the Posterior Longitudinal Ligament and Ossification of the Ligament Flavum in South Koreans: A Whole-Spine-CT-Based Cross-Sectional Study

Objective No studies assessing the prevalence of ossification of the spinal ligament were conducted using whole-spine positron emission tomography and computed tomography (PET-CT) in healthy Koreans. We aimed to determine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligament flavum (OLF) in healthy Koreans using whole-body PET-CT. Methods We reviewed whole-body PET-CT images captured during general health checkups at the General Health Promotion Center of our institution from January 2015 to 2020. OPLL and OLF were identified by the presence of heterotopic ossification in the posterior longitudinal ligament and ligament flavum on axial and sagittal PET-CT images. Results A total of 1,934 adults (1,645 men, 289 women) were included. The mean age was 48.05 years (range, 28–86 years). Among the 1,934 patients, 173 had OPLL (8.9%). The most commonly involved cervical vertebra levels arranged according to frequency were C4, C5, C3, and C6. OLF was observed in 125 patients (6.5%). The most commonly involved thoracic levels were T10, T11, and T5. The prevalence of OPLL and OLF was the highest in patients aged 60–69 years. Among the C-OPLL patients, 15.1% had T-OPLL, 5.0% had L-OPLL, and 25.8% had T-OLF. Conclusion Our study revealed the prevalence of OPLL and OLF in healthy Korean subjects. It was consistent with that in other Asian countries. The presence of OPLL and OLF at most locations correlated with the presence or absence of spinal ossification at other locations

Superconducting phase transitions in frustrated Josephson-junction arrays on a dice lattice

Transport measurements are carried out on dice Josephson-junction arrays with the frustration index $f=1/3$ and 1/2 which possess, within the limit of the $XY$ model, an accidental degeneracy of the ground states as a consequence of the formation of zero-energy domain walls. The measurements demonstrate that both the systems undergo a phase transition to a superconducting vortex-ordered state at considerably high temperatures. The experimental findings are in apparent contradiction with the theoretical expectation that frustration effects in the $f=1/3$ system are particularly strong enough to suppress a vortex-ordering transition down to near zero temperature. The data for $f=1/2$ are more consistent with theoretical evaluations. The agreement between the experiments and the Monte Carlo simulations of a $XY$ model for $f=1/3$ suggests that the order-from-disorder mechanism for the removal of an accidental degeneracy may still be effective in the $f=1/3$ system. The transport data also reveal that the dice arrays with zero-energy domain walls experience a much slower critical relaxation than other frustrated arrays only with finite-energy walls.Comment: 4 pages, 4 figure

Frustrated two-dimensional Josephson junction array near incommensurability

To study the properties of frustrated two-dimensional Josephson junction arrays near incommensurability, we examine the current-voltage characteristics of a square proximity-coupled Josephson junction array at a sequence of frustrations f=3/8, 8/21, 0.382 $(\approx (3-\sqrt{5})/2)$, 2/5, and 5/12. Detailed scaling analyses of the current-voltage characteristics reveal approximately universal scaling behaviors for f=3/8, 8/21, 0.382, and 2/5. The approximately universal scaling behaviors and high superconducting transition temperatures indicate that both the nature of the superconducting transition and the vortex configuration near the transition at the high-order rational frustrations f=3/8, 8/21, and 0.382 are similar to those at the nearby simple frustration f=2/5. This finding suggests that the behaviors of Josephson junction arrays in the wide range of frustrations might be understood from those of a few simple rational frustrations.Comment: RevTex4, 4 pages, 4 eps figures, to appear in Phys. Rev.