By means of Monte Carlo methods, we perform a full error analysis on the Duflo-Zucker mass model. In particular, we study the presence of correlations in the residuals to obtain a more realistic estimate of the error bars on the predicted binding energies. To further reduce the discrepancies between model prediction and experimental data we also apply a Multilayer Perceptron Neural Network. We show that the root mean square of the model further reduces of roughly 40%. We then use the resulting models to predict the composition of the outer crust of a non accreting neutron star. We provide a first estimate of the impact of error propagation on the resulting equation of state of the system.

The behaviour of the nuclear symmetry energy near saturation density is important for our understanding of dense nuclear matter. This density dependence can be parameterised by the nuclear symmetry energy and its derivatives evaluated at nuclear saturation density. In this work we show that the core-crust interface mode of a neutron star is sensitive to these parameters, through the (density-weighted) shear-speed within the crust, which is in turn dependent on the symmetry energy profile of dense matter. We calculate the frequency at which the neutron star quadrupole (ℓ = 2) crust-core interface mode must be driven by the tidal field of its binary partner to trigger a Resonant Shattering Flare (RSF). We demonstrate that coincident multimessenger timing of an RSF and gravitational wave chirp from a neutron star merger would enable us to place constraints on the symmetry energy parameters that are competitive with those from current nuclear experiments.

Purpose -The purpose of this paper is to explore two under-developed areas of board research: the corporate governance of unlisted companies; and board behaviour, focusing on process factors that contribute to a board performing effectively.Design/methodology/approach -The Board Effectiveness Questionnaire was completed by 67 directors, to gather views on how their board currently operates and how they think it should operate, across various behavioural areas relating to the relationships, decision making, the working climate and predispositions. Analysis of ''process losses'', the pattern of sub-optimal board behaviour, allowed the testing of four hypotheses concerning board effectiveness.Findings -The 18 most important and five least important behaviours were identified, plus 12 showing the greatest ''process loss''. Quality of team ''relationships'' is the main cause of loss whereas evidence for the impact of leadership style is mixed. Size of the board is related to overall performance of the board but number and proportion of non-executive directors are not.Research limitations/implications -This is a ''purposive, judgmental'' sample of all unlisted companies, derived from those who were willing and able to respond. Only one director's view of each board was sought. Practical implications -The picture of the ''ideal'' board provides a checklist for a company wishing to assess its board's performance as a working group, highlighting key characteristics that should be reflected on when discussing director/ board performance. The gaps in board behaviour identified could help other boards assess their own performance and researchers to focus on these areas.Originality/value -The paper explores two under-researched areas.

Resonant Shattering flares (RSFs) are bursts of gamma-rays expected to be triggered by tidal resonance of a neutron star (NS) during binary inspiral. They are strongly dependent on the magnetic field strength at the surface of the NS. By modelling these flares as being the result of multiple colliding relativistic shells launched during the resonance window, we find that the prompt non-thermal gamma-ray emission may have luminosity up to a few × 1048erg s−1, and that a broad-band afterglow could be produced. We compute the expected rates of detectable RSFs using the BPASS population synthesis code, with different assumptions about the evolution of surface magnetic field strengths before merger. We find the rate of detectable RSFs to be ∼0.0001–5 per year for BHNS mergers and ∼0.0005–25 per year for NSNS mergers, with the lower bound corresponding to surface-field decay consistent with magneto-thermal evolution in purely crustal fields, while the upper bounds are for systems which have longer-lived surface magnetic fields supported by flux frozen into the superconducting core. If some of the observed SGRB precursor flares are indeed RSFs, this suggests the presence of a longer-lived surface field for some fraction of the neutron star population, and that we could expect RSFs to be the most common detectable EM counterpart to GW detections of BHNS mergers. The non-detection of a RSF prior to GRB170817A provides an upper bound on the magnetic fields of the progenitor NSs of Bsurf ∼ 1013.5G.

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