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Background Hip-joint shape is an important factor that affects an individual's risk of developing osteoarthritis (OA). However, validated tools to quantify these morphological characteristics on clinical plain radiographs are few. We developed a Matlab-based Semi-automated HIP Software programme (SHIPS) that measures 10 morphologic characteristics of the hip that are risk factors for OA using a plain digitised antero-posterior pelvic radiograph. In this study we validated the accuracy and repeatability of this freeware-tool. Methods Software accuracy was assessed using a test pelvic radiograph, and by repeated measurements of an AP-pelvic radiograph digitally recreated from pelvis computed-tomography images reformatted to create images rotated in 2-dimensions (2.5° increments, range −15° to +15°). Intra- and inter-observer repeatability was assessed using pelvic radiographs from 30 subjects analysed twice using the software by two readers, and expressed as coefficient of variation (CV). Clinical-repeatability was assessed by measuring sequential pelvic radiographs taken on the same day after re-positioning in 23 subjects. Results Software accuracy was within 0.1% for linear-ratios and 0.4° for angular-measurements. Changes in pelvic inclination and rotation of ±15° resulted in Conclusion The software showed good accuracy and repeatability for measurement of most hip-joint morphologic risk factors for OA apart from HTE. This tool has particular value in studying large or retrospective datasets where cross-sectional imaging is not feasible or available.

Geophysical investigations on rock glaciers are often difficult because rock glaciers are covered by an unconsolidated debris mantle a few meters thick, are typically

Lode horizons north and south of the Broken Hill, New South Wales orebody contain a number of zones rich in sphalerite and poor in galena. One example is Pasminco Mining's new opencut Potosi Mine, which averages 8.5% Zn and 2% Pb with little other sulphide. The mineralisation at the Potosi Mine has been well defined by applied potential and induced polarisation (IP) surveys, but different techniques are required for deeper, downplunge exploration. Drillhole electromagnetics (DHEM) is routinely used but may miss those zones where sphalerite is almost the only sulphide. It was therefore decided to try a series of drillhole magnetometric resistivity (DHMMR) surveys, since this method responds to contrasting, rather than absolute, conductivity. The results were very successful with the known sulphides (and some previously unsuspected zones) responding at downhole depths of more than 600 m. The method has detected mineralisation at distances greater than 150 m from the drillhole and has given clear responses to sulphides where DHEM has failed. The method has less resolving capability than DHEM, although it has proven to be more definitive where sulphide lenses occur both above and below the drillhole. The results also suggest that the magnetic field, which responds to changes in resistivity, has a much larger search radius than the phase angle, which measures the IP effect. DHMMR is expected to play a wider role in the Broken Hill district and elsewhere, in the search for sphalerite-rich orebodies.

In this paper, we describe an instrument system for performing continuous resistivity profiling in shallow freshwater and marine environments. Using a streamer cable containing 9 electrodes, the system continuously samples the dipole-dipole resistivity at n-spacings 1 through 6. The system can be installed aboard a variety of small inboard or outboard powered vessels in a few hours. Hand-held or marine GPS units provide location information that is recorded by a laptop computer. With this system, up to 40 line-km/day of dipole-dipole data have been collected. The resistivity data are merged with the GPS positions as a post-processing step. The final step in the post-processing is the inversion of overlapping segments of each profile using a 2-D smooth model. The inversions provide high resolution images of the geoelectric cross-section. The depth of investigation ranges from 20-30 m, with a 10 m dipole spacing. Over the last 4-years, we have performed surveys on the Ohio River, near Louisville, KY, on tidal estuaries and bays along the Atlantic coast in Delaware, Maryland, Virginia, and North Carolina, and in Tampa Bay, Florida. Data from these surveys will be used to illustrate the final deliverable from a survey.