2,300 research outputs found

    Australia

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    This is a review of Australia (2008)

    Sherlock Holmes

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    This is a review of Sherlock Holmes (2009)

    Taken

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    This is a review of Taken (2008)

    Accuracy assessment of Tri-plane B-mode ultrasound for non-invasive 3D kinematic analysis of knee joints

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    BACKGROUND Currently the clinical standard for measuring the motion of the bones in knee joints with sufficient precision involves implanting tantalum beads into the bones. These beads appear as high intensity features in radiographs and can be used for precise kinematic measurements. This procedure imposes a strong coupling between accuracy and invasiveness. In this paper, a tri-plane B-mode ultrasound (US) based non-invasive approach is proposed for use in kinematic analysis of knee joints in 3D space. METHODS The 3D analysis is performed using image processing procedures on the 2D US slices. The novelty of the proposed procedure and its applicability to the unconstrained 3D kinematic analysis of knee joints is outlined. An error analysis for establishing the method's feasibility is included for different artificial compositions of a knee joint phantom. Some in-vivo and in-vitro scans are presented to demonstrate that US scans reveal enough anatomical details, which further supports the experimental setup used using knee bone phantoms. RESULTS The error between the displacements measured by the registration of the US image slices and the true displacements of the respective slices measured using the precision mechanical stages on the experimental apparatus is evaluated for translation and rotation in two simulated environments. The mean and standard deviation of errors are shown in tabular form. This method provides an average measurement precision of less than 0.1 mm and 0.1 degrees, respectively. CONCLUSION In this paper, we have presented a novel non-invasive approach to measuring the motion of the bones in a knee using tri-plane B-mode ultrasound and image registration. In our study, the image registration method determines the position of bony landmarks relative to a B-mode ultrasound sensor array with sub-pixel accuracy. The advantages of our proposed system over previous techniques are that it is non-invasive, does not require the use of ionizing radiation and can be used conveniently if miniaturized.This work has been supported by School of Engineering & IT, UNSW Canberra, under Research Publication Fellowship

    Public land commissions: Historical lessons and future considerations

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    Tau-p mapping and interpretation of seismic reflection data from the western Isles region of Scotland

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    Seismic data are conventionally recorded, processed and displayed in the X-T domain, where X is the source-receiver. offset and T is the two-way traveltime. There are advantages, however, in mapping the same data in a different domain; that of intercept time T and horizontal ray parameter p. Computer programs .written for performing the transformation from X-T to -p were adapted for use with marine data acquired in the western Isles region of Scotland in order to obtain information about the velocity structure in that area. The results obtained are compared with those produced by the more conventional methods of refraction surveying and it is found that the data are of insufficient quality to facilitate a geological interpretation to be made with the -p method alone and that the method is of no use with the poorest quality data. Recourse to the conventional methods is found to be necessary, and the results obtained verify previous results from other work

    Stable Isotope Studies of the Rochechouart Impact Structure: Sources of Secondary Carbonates and Sulphides within Allochthonous and Parautochthonous Impactites

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    Hypervelocity impacts are among the most ubiquitous processes to affect solid bodies within our solar system [1, 2]. Although they are notoriously devastating, citing responsibility for mass extinction events and global climate perturbations, impacts can also create temporary environments which are favorable for life to thrive, if there is enough water present in the target, and sufficient energy is released as heat [1, 2]. One-third of impact structures on Earth contain fossil impact-initiated hydrothermal systems, and they are therefore being explored as potential “cradles of life” on other solid planets and satellites in our solar system [1].<p></p> We are presenting a case for the evaluation of the Mesozoic Rochechouart impact structure in France as a once-habitable environment. Initial δ 13C, δ18O and δ 34S isotope data collected in 2014 from hydrothermal carbonates and sulphides within monomict lithic impact breccia, collected from a site located 7.5km from the center of the structure at Champagnac quarry, supports our hypothesis of a warm, wet environment; we also found evidence for metabolically reduced sulphate [3]. Similar mineral assemblages can be found throughout the structure, including allochthonous breccias and low to unshocked target material. In order to explore our hypothesis further, a larger sample set was collected from various lithologies within the Champagnac site containing sulphide and carbonate mineralization for δ 13C, δ18O and δ34S isotope analysis in January 2015. These results will allow us to determine the relationships between the many hydrothermal mineral assemblages within this area of the structure, and ask whether the isotopic compositions recorded in secondary sulphides and carbonates of the impactites are inherited from the target, or possibly represent colonization by thermophilic microbes during the post-impact hydrothermal period.<p></p&gt

    Friendly Foreigners: International Warfare, Resident Aliens and the Early History of Denization in England, c.1250–c.1400

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    The search for the origins of the process of denization in England has traditionally focused on the needs of merchants and the context of international trade, and no credible explanation has been given for why denization emerged as a recognisable Chancery form in the 1380s and 1390s. A new consideration of wartime treatment of aliens demonstrates the slow emergence, between c.1250 and c.1400, of an official policy towards lay foreigners that sought to minimise the disruptions arising in moments of national emergency and to accord rights of denizen equivalence to foreigners whose presence was profitable to the realm. In certain exceptional conditions during the 1270s and 1340s, alien residents with good connections at court could secure more developed statements of their rights as denizens. However, it was a series of events set off by the announcement of an intention to expel all French residents in 1377–78 that generated letters of protection containing specific reference to a change of allegiance, and thus established the principle that the recipient should renounce his former commitment and became a subject of the English Crown. Applied to other nationalities and outside the immediate context of war, these developments would give rise to the form known as letters of denization during the decades that followed

    Objective Lightning Forecasting at Kennedy Space Center/Cape Canaveral Air Force Station using Cloud-to-Ground Lightning Surveillance System Data

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    The 45th Weather Squadron (45 WS) forecasters at Cape Canaveral Air Force Station (CCAFS) in Florida include a probability of thunderstorm occurrence in their daily morning briefings. This information is used by personnel involved in determining the possibility of violating Launch Commit Criteria, evaluating Flight Rules for the Space Shuttle, and daily planning for ground operation activities on Kennedy Space Center (KSC)/CCAFS. Much of the current lightning probability forecast is based on a subjective analysis of model and observational data. The forecasters requested that a lightning probability forecast tool based on statistical analysis of historical warm-season (May - September) data be developed in order to increase the objectivity of the daily thunderstorm probability forecast. The tool is a set of statistical lightning forecast equations that provide a lightning occurrence probability for the day by 1100 UTC (0700 EDT) during the warm season. This study used 15 years (1989-2003) of warm season data to develop the objective forecast equations. The local CCAFS 1000 UTC sounding was used to calculate stability parameters for equation predictors. The Cloud-to-Ground Lightning Surveillance System (CGLSS) data were used to determine lightning occurrence for each day. The CGLSS data have been found to be more reliable indicators of lightning in the area than surface observations through local informal analyses. This work was based on the results from two earlier research projects. Everitt (1999) used surface observations and rawinsonde data to develop logistic regression equations that forecast the daily thunderstorm probability at CCAFS. The Everitt (1999) equations showed an improvement in skill over the Neumann-Pfeffer thunderstorm index (Neumann 1971), which uses multiple linear regression, and also persistence and climatology forecasts. Lericos et al. (2002) developed lightning distributions over the Florida peninsula based on specific flow regimes. The flow regimes were inferred from the average wind direction in the 1000-700 mb layer at Miami (MIA), Tampa (TBW), and Jacksonville (JAX), Florida, and the lightning data were from the National Lightning Detection Network. The results suggested that the daily flow regime may be an important predictor of lightning occurrence on KSC/CCAFS
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