A thematic analysis of factors influencing recruitment to maternal and perinatal trials

Background: Recruitment of eligible participants remains one of the biggest challenges to successful completion of randomised controlled trials (RCTs). Only one third of trials recruit on time, often requiring a lengthy extension to the recruitment period. We identified factors influencing recruitment success and potentially effective recruitment strategies. Methods: We searched MEDLINE and EMBASE from 1966 to December Week 2, 2006, the Cochrane Library Methodology Register in December 2006, and hand searched reference lists for studies of any design which focused on recruitment to maternal/perinatal trials, or if no studies of maternal or perinatal research could be identified, other areas of healthcare. Studies of nurses' and midwives' attitudes to research were included as none specifically about trials were located. We synthesised the data narratively, using a basic thematic analysis, with themes derived from the literature and after discussion between the authors. Results: Around half of the included papers (29/53) were specific to maternal and perinatal healthcare. Only one study was identified which focused on factors for maternal and perinatal clinicians and only seven studies considered recruitment strategies specific to perinatal research. Themes included: participant assessment of risk; recruitment process; participant understanding of research; patient characteristics; clinician attitudes to research and trials; protocol issues; and institutional or organisational issues. While no reliable evidence base for strategies to enhance recruitment was identified in any of the review studies, four maternal/perinatal primary studies suggest that specialised recruitment staff, mass mailings, physician referrals and strategies targeting minority women may increase recruitment. However these findings may only be applicable to the particular trials and settings studied. Conclusion: Although factors reported by both participants and clinicians which influence recruitment were quite consistent across the included studies, studies comparing different recruitment strategies were largely missing. Trials of different recruitment strategies could be embedded in large multicentre RCTs, with strategies tailored to the factors specific to the trial and institution.Rebecca L Tooher, Philippa F Middleton and Caroline A Crowthe

Aspects of the geology of the Stuart Creek area, north of Lake Torrens, South Australia

This item is only available electronically.An area to the north of Lake Torrens, encompassing the newly proclaimed Stuart Creek Precious Stones Field, was studied, with particular reference to the opal- bearing Cretaceous sediments. The pre-Mesozoic basement consists of Adelaidean rocks of the Wilpena Group in the east, separated from Lower Cambrian rocks by the Arthur Fault The relatively flat-lying Cretaceous sequence consists of two mappable units. The lower unit, called the "Stuart Creek Beds" in this thesis, is probably a transitional unit marking the transgression of the Lower Cretaceous sea. The early Aptian Marree Formation comprises bioturbated brown montmorillonitic muds with sandy and conglomeratic beds more prominent near the base. Scattered "erratics" occur. The original sediment, deposited in a marginal marine environment was black, pyritic and carbonaceous. It has been affected by a number of weathering events during the Tertiary. The uppermost portion has been very heavily weathered and bleached. Only a thin remnant exists now, due to erosion prior to Tertiary deposition The Tertiary sediments are mostly sands with some clays, silts and limestones. Milky quartz pebbles are a common characteristic. The sediments are non-marine, dominantly fluviatile. Silicification is common but variable. The sequence is correlated with the Mount Sarah Sandstone of Miocene age. Opal, occurring throughout the area, is believed to have formed associated with silicification of the Tertiary. The precious opal is notable in that it occurs within relatively fresh sediments, rather than highly weathered rocks as elsewhere in South Australia. Precious opal is only found on the Field, but all the Cretaceous must be considered potentially opal-bearing until further work is done.Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 197

Recent Observations on Tin Pest Formation in Solder Alloys

The most recent observations of the response of bulk samples of several lead-free solder alloys, exposed to temperatures below the allotropic transition for tin for extended periods, are reported. Tin pest has been observed in Sn-0.5Cu, Sn-3.5Ag, Sn-3.8Ag-0.7Cu, and Sn-3.0Ag-0.5Cu alloys at both -18 degrees C and -40 degrees C. The process is slow and inconsistent, usually requiring several years, but may eventually result in complete disintegration of the sample. No tin pest was detected in Sn-Zn-3Bi or in the traditional Sn-37Pb solder alloy after exposure for up to 4 and 10 years, respectively. It is suggested that nucleation is affected by local composition and that extremely small amounts of either intentional solute or impurity are influential. Growth of tin pest is accompanied by a large volume change, and it is likely that stress relaxation ahead of the expanding grey tin front is a controlling factor. A stronger matrix would be more resistant in this case, and at the temperatures of exposure Sn-37Pb is stronger than either Sn-3.5Ag or Sn-0.5Cu. The absence of tin pest, to date, on actual joints is attributed to their restricted free surface area and the greater strength associated with very small samples