Phase and amplitude recovery and diffraction image generation method: structure of Sb/Au(110)-radical3xradical3R54.7 degrees from surface X-ray diffraction.

The discovery that the phase problem of diffraction from non-periodic objects may be solved by oversampling the diffraction intensities in reciprocal space with respect to a Nyquist criterion has opened up new vistas for structure determination by diffraction methods. A similar principle may be applied to the problem of surface X-ray diffraction (SXRD), where, owing to the breaking of a crystal periodicity normal to its surface, diffraction data consist of a set of superstructure rods (SRs) due to scattering from the parts of the surface whose structure is different from that of the truncated bulk and of crystal truncation rods (CTRs), formed by interfering contributions from the surface and the bulk. A phase and amplitude recovery and diffraction image generation method (PARADIGM) is described that provides a prescription for finding the unmeasured amplitudes and phases of the surface contributions to the CTRs in addition to the phases of the SRs, directly from the diffraction data. The resulting ;diffraction image' is the basis of a determination of the previously unknown multidomain structure of Sb/Au(110)-radical3xradical3R54.7 degrees.

Lattice location of trace elements within minerals and at their surfaces with X-ray standing waves.

The x-ray standing waves generated by dynamical Bragg diffraction were used to directly measure lattice locations of trace elements within and at the surface of a mineral single crystal. These high-precision measurements were made on natural Iceland spar calcite cleaved along the (1014) plane and reacted with a dilute aqueous lead solution. Within the bulk crystal, naturally occurring trace manganese was found within (1014) planes, consistent with its substitution for calcium. At the crystal surface, sorbed lead was found to be highly ordered and mostly within (1014) planes. This demonstrates a powerful application of synchrotron radiation in the earth and environmental sciences.

Using the newspaper to disseminate vasectomy information in kenya.

Recent research in Kenya shows that, although there is still a high population growth rate, there is increasing interest among men as well as women in family planning and in limiting family size. Vasectomy, however, is little known and practiced in Kenya. A major reason for this is a general lack of knowledge about the procedure and where it may be obtained. Little effort has been put into addressing the barriers to vasectomy acceptance in Kenya, partly because of the commonly held assumption that Kenyan men would not be interested in the method. Innovative Communication Systems, with the support of the Association for Voluntary Surgical Contraception, implemented a study using the print media to examine this perception. Advertisements providing information about the method were placed in newspapers and a magazine. An unexpectedly large response was received-over 800 written requests for information from all parts of the country. The majority of inquiries were from rural areas, and there was a high proportion of requests from the coastal district, a Muslim area generally considered to be extremely resistant to family planning. A large proportion of inquiries came through a Kiswahili newspaper appealing to lower socioeconomic groups.