Abstract. Field observations were made in 3-4 m water depth of linear transition ripple geometry and migration using a high-resolution laser-video bed profiling system and acoustic scanning sensors during both the growth and decay phases of an autumn storm event. Linear transition ripples are long-crested, low-steepness bedforms of the anorbital ripple type and were observed to occur here at relatively high wave energies just below the fiatbed threshold, with wavelengths of 8.5 4-0.5 cm and heights of 0.3 + 0.1 cm. The maximum observed migration rate was 0.7 cm/min. Migration was offshore during storm growth and onshore during storm decay. The observed ripple migration velocities were highly correlated (r 2 > 0.7) with nearbed wave orbital velocity skewhess in both cross--shore directions. During storm growth the incident wave spectrum was bimodal and the orbital velocity skewhess was negative. During storm decay the xvave spectrum was unimodal and the velocity skewhess was positive. Bispectral analysis shows that the main contribution to negative velocity ske•vness during storm growth was due to a difference interaction between the two principal (sea and swell) components of the bimodal velocity spectrum. Positive skewhess during storm decay was due to selfself interaction of the narrowband residual swell. The negative velocity skewhess observed during storm growth is consistent with prediction by a two-frequency second-order wave theory.

An inversion algorithm for extracting suspended sand size and concentration from simultaneous backscattered acoustic pressure amplitude at three operating frequencies is presented. The algorithm is based on the differences in signal amplitude between different frequency pairs, and is tested using laboratory measurements of multifrequency backscatter from a turbulent sediment-carrying jet. Concentration and size profiles inverted from field and laboratory data are compared with results from a previously developed algorithm based on signal ratios. The difference inversion scheme is less sensitive to errors arising from low signal levels, allowing the size/concentration measurement range to be extended to regions of lower concentration. The concentrations from the field data agree well with independent optically determined estimates. The results demonstrate sensitivity to the backscatter form factor. PACS numbers: 43.30. Gv, 43.30.Ft signal levels (particularly in the denominator of a ratio) contribute to increased noise level in the inverted results. An alternative method is presented here which, by using the differences between signal levels, is less prone to noise in regions of low scatterer concentration. This paper contains a description of the new inversion method and results from laboratory and field experiments.The inverted sizes and concentrations from the laboratory experiments are compared to physical measurements of these quantities and concentrations determined from the field data are compared to optical measurements. Comparison to results obtained using the ratio algorithm are also presented.Proper extraction of the size information from the multifrequency data by any method requires prior knowledge of the size/frequency dependence of the backscatter signal. Factors such as the material composition of the scatterers can introduce variation in the scattering cross section, even locally. The sensitivity of inverted results to small differences in the backscatter form factor is investigated. In addition, it is necessary to know the effect of attenuation of the signal by scatterers. Measurements and discussion of scattering attenuation are presented in the Appendix. I. MEASUREMENT TECHNIQUEThe multifrequency acoustic backscatter system, RAS-TRAN system 1, has been described in detail elsewhere. •ø'•2 The transceivers operate at three frequencies ( 1, 2.25, and 5 MHz), and over a range of about 1 m. Data from each of the units is logged on a CAMAC-crate and PC-based data acquisition system. •2'•3In the laboratory studies, •3 an axisymmetric region of statistically steady scatterer concentration is maintained by a recirculating jet carrying sand of known size. Independent concentration measurements are obtained by syphon between acoustic runs. The beams intersect at the center of the jet 28 cm downstream from the nozzle, 55 cm away from the three transceivers. Backscatter profiles across the jet were acquired at a rate of 6.6 Hz, with four-ping ensemble averaging and block averaging of three adjacent sample ...

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IntroductionDiabetes-related foot disease is a large cause of the global disease burden yet receives very little research funding to address this large burden. To help address this gap, it is recommended to first identify the consensus priority research questions of relevant stakeholders, yet this has not been performed for diabetes-related foot disease. The aim of this study was to determine the national top 10 priority research questions for diabetes-related foot health and disease from relevant Australian stakeholders.Research design and methodsA modified three-round Delphi online survey design was used to seek opinions from relevant Australian stakeholders including those with diabetes or diabetes-related foot disease or their carers (consumers), health professionals, researchers and industry. Participants were recruited via multiple public invitations and invited to propose three research questions of most importance to them (Round 1), prioritize their 10 most important questions from all proposed questions (Round 2), and then rank questions in order of importance (Round 3).ResultsAfter Round 1, a total of 226 unique questions were proposed by 210 participants (including 121 health professionals and 72 consumers). Of those participants, 95 completed Round 2 and 69 completed Round 3. The top 10 priority research questions covered a range of topics, including health economics, peripheral neuropathy, education, infection, technology, exercise, and nutrition. Consumers prioritized peripheral neuropathy and prevention-related questions. Health professionals prioritized management-related questions including Australia’s First Peoples foot health, health economics and infection questions.ConclusionsThese priority research questions should guide future national research agendas, funding and projects to improve diabetes-related foot disease burdens in Australia and globally. Future research should focus on consumer priority research questions to improve the burden of diabetes-related foot disease on patients and nations. Further research should also investigate reasons for different priorities between consumers and health professionals.

[1] Field observations of linear transition ripples during an autumn storm exhibit high correlation between cross-shore ripple migration rate and the skewness of the near-bed wave orbital velocity. For a bimodal spectrum of mixed sea and swell, negatively skewed near-bed orbital velocities were accompanied by offshore ripple migration, while for unimodal swell, ripples migrated onshore under positively skewed velocities. Bispectral analysis and weakly nonlinear wave theory are used to show that the positive and negative velocity skewness arose from higher-order interactions between frequency components of the incident wave spectrum. There is good quantitative agreement between predicted and observed velocity skewness, indicating a connection between ripple migration and wave-wave interactions.