7 research outputs found
Why we need easy access to all data from all clinical trials and how to accomplish it
International calls for registering all trials involving humans and for sharing the results, and sometimes also the raw data and the trial protocols, have increased in recent years. Such calls have come, for example, from the Organization for Economic Cooperation and Development (OECD), the World Health Organization (WHO), the US National Institutes of Heath, the US Congress, the European Commission, the European ombudsman, journal editors, The Cochrane Collaboration, and several funders, for example the UK Medical Research Council, the Wellcome Trust, the Bill and Melinda Gates Foundation and the Hewlett Foundation
Stable magnetic fields in stellar interiors
We investigate the 50-year old hypothesis that the magnetic fields of
the Ap stars are stable
equilibria that have survived in these stars since their formation. With numerical
simulations we find that stable magnetic field configurations indeed appear to exist under
the conditions in the radiative interior of a star. Confirming a
hypothesis by Prendergast (1956, ApJ, 123, 498), the
configurations have roughly equal poloidal and toroidal field strengths. We find that tori of
such twisted fields can form as remnants of the decay of an unstable random
initial field. In agreement with observations, the appearance at the surface is an
approximate dipole with smaller contributions from higher multipoles, and the surface field
strength can increase with the age of the star. The results of this
paper were summarised by Braithwaite & Spruit (2004, Nature, 431, 891)