Planned caesarean section (CS) for second birth following a first vaginal birth (VB)

Introduction There is international concern over rising rates of CS and its impacts on maternal and neonatal health outcomes. Of interest are the factors driving the increase in primary caesareans in a 2nd birth. Objectives To examine effects of previous birth factors on subsequent planned CS. Methods Women with both 1st and 2nd births were identified from NSW birth data from 2000-2009. The study population included only women with VB at 1st birth and excluded those who had an indisputable indication for CS in the 2nd birth (multiple pregnancy, breech presentation or placenta praevia). Logistic regression was used for the analysis. Results Of the 114,287 women, 4,787 (4.2%) had planned CS at 2nd birth. After adjusting for 2nd pregnancy risk factors including interval between two births, year at birth, maternal age, hospital location, private care, hypertension, diabetes, infant size and antepartum hemorrhage, independent 1st birth risk factors for planned CS (in order of effect size) were 3rd-4th degree tear, severe neonatal morbidity, a perinatal death, severe maternal morbidity, instrumental birth, large infant, labour induction, epidural, use of oxytocics and episiotomy. The leading four 1st birth risk factors increased the risk of planned CS by more than 100%, for example odds ratio of 3rd-4th degree tear: 5.00 (95% CI 4.58-5.44). Conclusion Women who had obstetric interventions and adverse pregnancy outcomes in the first birth were at increased risk of planned CS in the second birth. The results indicate the importance of ‘getting the first birth right’ in reducing CS rate.Australian National Health and Medical Research Council (NHMRC) Capacity Building Grant (#573122

Edge states induce boundary temperature jump in molecular dynamics simulation of heat conduction

We point out that the origin of the commonly occurred boundary temperature jump in the application of No\'se-Hoover heat bath in molecular dynamics is related to the edge modes, which are exponentially localized at the edge of the system. If heat baths are applied to these edge regions, the injected thermal energy will be localized thus leading to a boundary temperature jump. The jump can be eliminated by shifting the location of heat baths away from edge regions. Following this suggestion, a very good temperature profile is obtained without increasing any simulation time, and the accuracy of thermal conductivity calculated can be largely improved.Comment: accepted by PRB, brief report, references added, typo correcte

From M-ary Query to Bit Query: a new strategy for efficient large-scale RFID identification

The tag collision avoidance has been viewed as one of the most important research problems in RFID communications and bit tracking technology has been widely embedded in query tree (QT) based algorithms to tackle such challenge. Existing solutions show further opportunity to greatly improve the reading performance because collision queries and empty queries are not fully explored. In this paper, a bit query (BQ) strategy based Mary query tree protocol (BQMT) is presented, which can not only eliminate idle queries but also separate collided tags into many small subsets and make full use of the collided bits. To further optimize the reading performance, a modified dual prefixes matching (MDPM) mechanism is presented to allow multiple tags to respond in the same slot and thus significantly reduce the number of queries. Theoretical analysis and simulations are supplemented to validate the effectiveness of the proposed BQMT and MDPM, which outperform the existing QT-based algorithms. Also, the BQMT and MDPM can be combined to BQMDPM to improve the reading performance in system efficiency, total identification time, communication complexity and average energy cost