Neonatal trials which include preterm babies often recruit multiples (twins or higher order births). For such trials, methodological decisions must be made regarding recruitment and randomisation of multiples. Enrolment can take place in complicated and challenging situations which are compounded if one or more babies die. In the BRACELET Study (Bereavement and Randomised Controlled Trials) (ht...

We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of ...

There has been a significant increase in the number of twins and higher multiples so that one child in 33 is now a multiple. It is therefore not unusual for schools to have several sets of twins, as well as triplets and even higher multiples. By being the same age and in the same school year if not class, twins and higher multiples are not like brothers and sisters born closely together. Teache...

‎In this paper‎, ‎we characterize the class of orthogonality preserving operators on an infinite-dimensional Hilbert space $H$ as scalar multiples of unitary operators between $H$ and some closed subspaces of $H$‎. ‎We show that any circle (centered at the origin) is the spectrum of an orthogonality preserving operator‎. ‎Also‎, ‎we prove that every compact normal operator is a strongly orthogo...

A shot-profile migration algorithm is modified to image multiple reflections at their correct location in the subsurface. This method replaces the impulsive source with an areal source made of recorded primaries and multiples. In addition, the extrapolated wavefield at the receivers consists of recorded multiples only which have been previously separated from the primaries. Migration results wi...

Downgoing/upgoing P/S-wave decomposition of ocean-bottom seismic (OBS) multicomponent data can help suppress the water-layer multiples and cross-talks between P- S-waves, therefore plays an important role in migration construction S-wave velocity models. We proposed novel composite calibration filters by introducing additional dimension to particle components, extending wave-equation-based adap...

Marchenko imaging can produce seismic reflection images in which artifacts related to multiples are suppressed. However, in state-of-the-art implementations, multiples do not contribute to the imaged reflectors. With an “event-byevent” deconvolution imaging approach, it is possible to use multiples in Marchenko imaging. We illustrate this for a 1D reflection response in which the primary reflec...

Proof. First, we’ll give an intuitive proof. Let b > 0 be given. Mark off multiples of b on the number line. The integer a will fall between two different multiples. qb is the smaller multiple, and r is the distance from qb to a. Clearly the choices of q and r are unique. Why we need the well-ordering principle: it’s not clear that a will fall between two different multiples of b if the numbers...