A survey of impulsive trajectories Final report

Literature survey of astrodynamics problems on intercept, transfer, and rendezvous trajectorie

Analytical Hartree-Fock gradients for periodic systems

We present the theory of analytical Hartree-Fock gradients for periodic systems as implemented in the code CRYSTAL. We demonstrate how derivatives of the integrals can be computed with the McMurchie-Davidson algorithm. Highly accurate gradients with respect to nuclear coordinates are obtained for systems periodic in 0,1,2 or 3 dimensions.Comment: accepted by International Journal of Quantum Chemistr

Precision orbit computations for an operational environment

Taking advantage of the improvements to the Earth's gravitation field and tracking station coordinates, an orbital computational consistency of the order of 5 meters was achieved for total position differences between orbital solutions for the Seasat and GEOS-3. The main source of error in these solutions was in the mathematical models that are required to generate these results, i.e., gravitation, atmospheric drag, etc. Different Earth gravitation fields and tracking coordinates were analyzed and evaluated in obtaining these computational results. Comparisons and evaluations of the Seasat results were obtained in terms of different solution types such as the Doppler only, Laser only, Doppler and Laser, etc. Other investigation using the Seasat data were made in order to determine their effect on the computational results at this particular level of consistency

Recent trends in cancer mortality in the UK

Comparisons of survival rates of given diseases with different treatments or in different places often gave misleading results until the introduction of controlled trials. Recent reports of relatively low survival rates following the treatment of cancer in the UK compared to the rates in other countries, not based on controlled trials, may consequently be misleading. Their validity has, therefore, been tested by comparing the levels and trends in mortality – the ultimate criterion by which the success or failure of any system of care can be judged. For this purpose, rates and trends in rates over 20–50 years have been compared in five European countries of similar economic status (France, Italy, the Netherlands, Sweden, and the UK). The UK rates are not generally worse than those in the other countries and are sometimes better. Exceptions were cancer of the lung, large bowel, and breast, the first of which is explained by differences in the prevalence of smoking