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Characteristics of older adult volunteers and nonvolunteers who were active in a community center's programs were compared in order to determine correlates of voluntarism. Only two variables significantly differentiated: sex and past patterns of organizational participation. Findings suggest a high degree of consistency between past and present activity patterns of older adults. Implications related to pre-retirement planning and to the appropriate placement of the elderly in post-retirement activities.

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We have made measurements of the extremal cross-sectional areas of the open hole surface of the Fermi surface of platinum for the previously unobserved, heavy mass orbits centered on F and X with the magnetic field along the [100] and [110] directions, respectively. When combined with previous measurements, the necessary data associated with all classes of orbits on all three sheets of the surface are now available. Using a relativistic non-muffin-tin, Korringa-Kohn-Rostoker formalism, data were fitted using the scattering phase shifts associated with the appropriate irreducible relativistic cubic representations as disposable parameters (through l = 2) to an accuracy of 0.3%. The resulting radii of all sheets of the Fermi surface are reported. A volume integration yields the necessary charge neutrality for this even-valent metal to within 1%. Next, available cyclotron mass data were fitted using the energy derivatives of the scattering phase shifts as disposable parameters (many-body effects being absorbed in the parameter set) to an accuracy of 3.4 % ; here the measured total electronic density of states was used as a constraint. The resulting Fermi velocities are also reported.