16 research outputs found

    Resonant two-site tunnelling dynamics of bosons in a tilted optical superlattice

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    We study the non-equilibrium dynamics of a 1D Bose-Hubbard model in a gradient potential and a superlattice, beginning from a deep Mott insulator regime with an average filling of one particle per site. Studying a quench that is near resonance to tunnelling of the particles over two lattice sites, we show how a spin model emerges consisting of two coupled Ising chains that are coupled by interaction terms in a staggered geometry. We compare and contrast the behavior in this case with that in a previously studied case where the resonant tunnelling was over a single site. Using optimized tensor network techniques to calculate finite temperature behavior of the model, as well as finite size scaling for the ground state, we conclude that the universality class of the phase transition for the coupled chains is that of a tricritical Ising point. We also investigate the out-of-equilibrium dynamics after the quench in the vicinity of the resonance and compare dynamics with recent experiments realized without the superlattice geometry. This model is directly realizable in current experiments, and reflects a new general way to realize spin models with ultracold atoms in optical lattices.Comment: 12 pages, 6 figure

    Comparison of diurnal variations, gestational age and gender related differences in fetal heart rate (FHR) parameters between appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) fetuses in the home environment

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    Objective To assess the influence of gender, time of the day and gestational age on fetal heart rate (FHR) parameters between appropriate-for-gestational-age (AGA) and small-for-gestational age (SGA) fetuses using a portable fetal ECG monitor employed in the home setting. Methods We analysed and compared the antenatal FHR data collected in the home setting on 61 healthy pregnant women with singleton pregnancies from 24 weeks gestation. Of the 61 women, 31 had SGA fetuses (estimated fetal weight below the tenth gestational centile) and 30 were pregnant with AGA fetuses. FHR recordings were collected for up to 20 h. Two 90 min intervals were deliberately chosen retrospectively with respect to signal recording quality, one during day-time and one at night-time for comparison. Results Overall, success rate of the fetal abdominal ECG in the AGA fetuses was 75.7% compared to 48.6% in the SGA group. Based on randomly selected episodes of heart rate traces where recording quality exceeded 80% we were able to show a marginal difference between day and night-time recordings in AGA vs. SGA fetuses beyond 32 weeks of gestation. A selection bias in terms of covering different representation periods of fetal behavioural states cannot be excluded. In contrast to previous studies, we neither controlled maternal diet and activity nor measured maternal blood hormone and heart rate as all mothers were monitored in the home environment. Conclusion Based on clinically unremarkable, but statistically significant differences in the FHR parameters between the AGA and SGA group we suggest that further studies with large sample size are required to assess the clinical value of antenatal fetal ECG monitoring

    Identification of first stage labor arrest by electromyography in term nulliparous women after induction of labor

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    INTRODUCTION: Worldwide induction and cesarean delivery rates have increased rapidly, with consequences for subsequent pregnancies. The majority of intra-partum cesarean deliveries are performed for failure to progress, typically in nulliparous women at term. Current uterine registration techniques fail to identify inefficient contractions leading to first stage labor arrest. An alternative technique, uterine electromyography has been shown to identify inefficient contractions leading to first stage arrest of labor in nulliparous women with spontaneous onset of labor at term. The objective of this study was to determine whether this finding can be reproduced in induction of labor MATERIAL AND METHODS: Uterine activity was measured in 141 nulliparous women with singleton term pregnancies and a fetus in cephalic position during induced labor. Electrical activity of the myometrium during contractions was characterized by its power density spectrum RESULTS: No significant differences were found in contraction characteristics between women with induced labor delivering vaginally with or without oxytocin and women with arrested labor with subsequent cesarean delivery CONCLUSION: Uterine electromyography shows no correlation with progression of labor in induced labor, which is in contrast to spontaneous labor. This article is protected by copyright. All rights reserved

    Uterine electromyography for identification of first-stage labor arrest in term nulliparous women with spontaneous onset of labor

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    <p>OBJECTIVE: We sought to study whether uterine electromyography (EMG) can identify inefficient contractions leading to first-stage labor arrest followed by cesarean delivery in term nulliparous women with spontaneous onset of labor.</p><p>STUDY DESIGN: EMG was recorded during spontaneous labor in 119 nulliparous women with singleton term pregnancies in cephalic position. Electrical activity of the myometrium during contractions was characterized by its power density spectrum (PDS).</p><p>RESULTS: Mean PDS peak frequency in women undergoing cesarean delivery for first-stage labor arrest was significantly higher (0.55 Hz), than in women delivering vaginally without (0.49 Hz) or with (0.51 Hz) augmentation of labor (P = .001 and P = .01, respectively). Augmentation of labor increased the mean PDS frequency when comparing contractions before and after start of augmentation. This increase was only significant in women eventually delivering vaginally.</p><p>CONCLUSION: Contraction characteristics measured by uterine EMG correlate with progression of labor and are influenced by labor augmentation.</p>

    Development of Nationwide Recommendations to Support Prenatal Counseling in Extreme Prematurity

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    Contains fulltext : 204177.pdf (publisher's version ) (Closed access)OBJECTIVES: To develop a nationwide, evidence-based framework to support prenatal counseling in extreme prematurity, focusing on organization, decision-making, content, and style aspects. METHODS: A nationwide multicenter RAND-modified Delphi method study was performed between November 2016 and December 2017 in the Netherlands. Firstly, recommendations were extracted from literature and previous studies. Secondly, an expert panel (n = 21) with experienced parents, obstetricians, and neonatologists rated the recommendations on importance for inclusion in the framework. Thirdly, ratings were discussed in a consensus meeting. The final set of recommendations was approved and transformed into a framework. RESULTS: A total of 101 recommendations on organization, decision-making, content, and style were included in the framework, including tools to support personalization. The most important recommendations regarding organization were to have both parents involved in the counseling with both the neonatologist and obstetrician. The shared decision-making model was recommended for deciding between active support and comfort care. Main recommendations regarding content of conversation were explanation of treatment options, information on survival, risk of permanent consequences, impossibility to predict an individual course, possibility for multiple future decision moments, and a discussion on parental values and standards. It was considered important to avoid jargon, check understanding, and provide a summary. The expert panel, patient organization, and national professional associations (gynecology and pediatrics) approved the framework. CONCLUSIONS: A nationwide, evidence-based framework for prenatal counseling in extreme prematurity was developed. It contains recommendations and tools for personalization in the domains of organization, decision-making, content, and style of prenatal counseling
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