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In coastal water systems, horizontal chaotic dispersion plays a significant role in the distribution and fate of pollutants. Lagrangian Coherent Structures (LCSs) provide useful tools to approach the problem of the transport of pollutants and have only recently been applied to coastal waters. While the fundamentals of the LCS approach using idealised analytical flow fields are well established in the literature, there are limited studies on their practical implementations in coastal waters where effects of boundaries and bathymetry frequently become significant. Due to their complex bathymetry and boundaries, unstructured grid systems are commonly used in modelling of coastal waters. For convenient derivation of LCS diagnostics, structured grids are commonly used. Here we examine the effect of mesh resolution, interpolation schemes and additive random noise on the LCS diagnostics in relation to coastal waters. Two kinematic model flows, the double gyre and the meandering jet, as well as validated outputs of a hydrodynamic model of Moreton Bay, Australia, on unstructured grids are used. The results show that LCSs are quite robust to the errors from interpolation schemes used in the data conversion from unstructured to structured grid. Attributed to the divergence in the underlying flow field, the results show that random errors in the order of 1-10 % cause a break down in the continuity of ridges of maximum finite time Lyapunov exponents and closed orbit elliptic LCSs. The result has significant implications on the suitability of applying LCS formulations based on a deterministic flow field to diffusive coastal waters., Comment: 33 Pages, 18 figure, Under review

Coastal tidal estuaries are vital to the exchange of energy and material between inland waters and the open ocean. Debris originating from the land and ocean enter this environment and are transported by currents (river outflow and tide), wind, waves and density gradients. Understanding and predicting the source and fate of such debris has considerable environmental, economic and visual importance. We show that this issue can be addressed using the Lagrangian coherent structures (LCS) technique which is highly robust to hydrodynamic model uncertainties. Here we present a comprehensive study showing the utility of this approach to describe the fate of floating material in a coastal tidal embayment. An example is given from Moreton Bay, a semi-enclosed subtropical embayment with high morphologic, ecological and economic significance to Southeast Queensland, Australia. Transport barriers visualised by the LCS create pathways and barriers for material transport in the embayment. It was found that the wind field modified both the rate attraction and location of the transport barriers. One of the key outcomes is the demonstration of the significant role of islands in partitioning the transport of material and mixing within the embayment. The distribution of the debris sources along the shoreline are explained by the relative location of the LCS to the shoreline. Therefore, extraction of LCS can help to predict sources and fate of anthropogenic marine debris and thus, serve as a useful way for effective management of vulnerable regions and marine protected areas., Comment: 34 pages, 11 figures, In press with Science of the Total Environment

We present the SI and other unit systems, including cgs-em and cgs-es, in a framework whereby a system of fully independent and dimensionally orthogonal base units is modified by conventions designed to simplify the equations that are used within each system. We propose that the radian can be seen as an independent unit whose dimensional status is modified in the SI and other unit systems for this purpose. This framework clarifies how different unit systems are interrelated, and identifies the key pieces of information that are needed to define both a unit system and the equations that are to be used with it. Specifically, these are the size of the base units in the unsimplified system, together with sufficient equations to identify all the conventions adopted by the particular unit system. The appropriate extra information for the revised SI is presented. We do not propose that the treatment of angles as dimensionless within the SI is changed. It is also proposed that the Gaussian unit system is best seen as identical to cgs-es, but with the B and H symbols in equations used to represent relativistic versions of B and H, which should properly be treated as different quantities. These different versions of B and H can similarly be used within the SI, with many of the advantages of the Heaviside-Lorentz system., Comment: 10 pages, accepted by Metrologia

The treatment of angles within the SI is anomalous compared with other quantities, and there is a case for removing this anomaly by declaring plane angle to be an additional base quantity within the system. It is shown that this could bring several benefits in terms of treating angle on an equal basis with other metrics, removing potentially harmful ambiguities, and bringing SI units more in line with concepts in basic physics, but at the expense of significant upheaval to familiar equations within mathematics and physics. This paper sets out the most important of these changes so that an alternative unit system containing angle as a base quantity can be seen in the round, irrespective of whether it is ever widely adopted. The alternative formulas and units can be treated as the underlying, more general equations of mathematical physics, independent of the units used for angle, which are conventionally simplified by implicitly assuming that the unit used for angle is the radian., Comment: 9 pages; accepted by Metrologia

An excellent candidate for a young elliptical, or `protoelliptical' galaxy is NGC 1700. Here we present new B, V and I band imaging using the Keck telescope and reanalyse existing V and I band images from the Hubble Space Telescope. After subtracting a model of the galaxy from the Keck images NGC 1700 reveals two symmetric tidal tail-like structures. If this interpretation is correct, it suggests a past merger event involving two spiral galaxies. These tails are largely responsible for the `boxiness' of the galaxy isophotes observed at a radius of about 13 kpc. We also show that the B-I colour distribution of the globular cluster system is bimodal. The mean colour of the blue population is consistent with those of old Galactic globular clusters. Relative to this old, metal poor population, we find that the red population is younger and more metal rich. This young population has a similar age and metallicity as that inferred for the central stars, suggesting that they are both associated with an episode of star formation triggered by the merger that may have formed the galaxy. Although possessing large errors, we find that the majority of the age estimates of NGC 1700 are reasonably consistent and we adopt a `best estimate' for the age of 3.0 +/-1.0 Gyr. This relatively young age places NGC 1700 within the age range where there is a notable lack of obvious candidates for protoellipticals. The total globular cluster specific frequency is rather low for a typical elliptical, even after taking into account fading of the galaxy over the next 10 Gyr. We speculate that NGC 1700 will eventually form a relatively `globular cluster poor' elliptical galaxy., Comment: 15 pages, 15 figures, accepted for publication in MNRAS

Theories of medically unexplained illness based on the concepts of dissociation, conversion, and somatization are summarized. Evidence cited in support of these theories is described and the conceptual strengths and shortcomings of each approach are considered. It is argued that each of these approaches adds to the understanding of unexplained illness but that none is able to provide a comprehensive explanation of the phenomenon. An integrative conceptual model of unexplained illness based on cognitive psychological principles is then presented. This model attempts to combine existing theoretical approaches within a single explanatory framework, extending previous theory by explaining how compelling symptoms can exist in the absence of organic pathology. The clinical and empirical implications of the model are then considered.