Generic bounds on dipolar gravitational radiation from inspiralling compact binaries

Various alternative theories of gravity predict dipolar gravitational radiation in addition to quadrupolar radiation. We show that gravitational wave (GW) observations of inspiralling compact binaries can put interesting constraints on the strengths of the dipole modes of GW polarizations. We put forward a physically motivated gravitational waveform for dipole modes, in the Fourier domain, in terms of two parameters: one which captures the relative amplitude of the dipole mode with respect to the quadrupole mode ($\alpha$) and the other a dipole term in the phase ($\beta$). We then use this two parameter representation to discuss typical bounds on their values using GW measurements. We obtain the expected bounds on the amplitude parameter $\alpha$ and the phase parameter $\beta$ for Advanced LIGO (AdvLIGO) and Einstein Telescope (ET) noise power spectral densities using Fisher information matrix. AdvLIGO and ET may at best bound $\alpha$ to an accuracy of $\sim10^{-2}$ and $\sim10^{-3}$ and $\beta$ to an accuracy of $\sim10^{-5}$ and $\sim10^{-6}$ respectively.Comment: Matches with the published versio

External cephalic version at 36 weeks and its outcome

Background: External cephalic version (ECV) is well known non-invasive procedure done for the management of breech presentation but is not routinely practised by obstetricians in many clinical settings. The aim of the study was to assess the success rate of external cephalic version, labour outcome of pregnancy after successful ECV, to study maternal and foetal complications associated with ECV and to explore the reasons for failed ECV.Methods: It was a prospective interventional study to assess the labour outcomes of pregnancies with successful and uncomplicated ECV. All women who had singleton breech presentation at 36+ weeks were included unless contraindications for ECV were present. After obtaining consent, ECV was attempted after giving tocolysis.Results: The total number of deliveries was 6038 in the same period. Out of these 301 were breech presentations thus the incidence of breech presentation was 4.9%. ECV was offered to 81 women (26.9%) and out of these 77 women (95.06%) gave consent for the procedure. The remaining 4 (4.93%) did not give consent due to anxiety about the procedure. The success rate was 54.54%. Out of total 301 women with breech presentation 40 women (13.3%) had assisted breech delivery and 216 women (71.8%) had caesarean section due to obstetric indications. Thus the caesarean section rate for breech presentation at our institute was 71.8%. ECV was successful in 63.82% of the multigravida on which it was attempted as compared to 40% of the primigravida. The success rate of ECV in the present study is maximum when ECV was performed at a gestational age of 38-39 weeks and when fetal weight was less than 3000 grams. Out of the 42 successful ECV cases, 4 babies (9.52%) had neonatal sepsis and 1 was still born (2.3%) which was unrelated to ECV.Conclusions: ECV is a valuable though under used option in the management of breech presentation at term. It is a relatively safe procedure, simple to learn and perform. Vigilance for breech presentation after 36 weeks is important. ECV at term using tocolytics should be part of the routine management of breech presentation