This study tested the hypothesis that olfactory dysfunction could discriminate between groups of patients with Alzheimer's disease and major depression. Forty patients meeting DSM-IV criteria for Alzheimer's disease and for major depression (20 per group) underwent assessment with the Pocket Smell Test (PST), a three-item screening measure of cranial nerve I function. A PST score of < or = 1 (1 or 0 correct) discriminated between the groups with a hit rate of 90% (sensitivity = 80%, specificity = 100%). Olfactory assessment may be a useful adjunctive screening measure in differentiating Alzheimer's disease from depression in elderly patients.
Understanding solute mixing within real vegetation is critical to predicting and evaluating the performance of engineered natural systems such as storm water ponds. For the first time, mixing has been quantified through simultaneous laboratory measurements of transverse and longitudinal dispersion within artificial and real emergent vegetation. Dispersion coefficients derived from a routing solution to the 2‐D Advection Dispersion Equation (ADE) are presented that compare the effects of vegetation type (artificial, Typha latifolia or Carex acutiformis) and growth season (winter or summer). The new experimental dispersion coefficients are plotted with the experimental values from other studies and used to review existing mixing models for emergent vegetation. The existing mixing models fail to predict the observed mixing within natural vegetation, particularly for transverse dispersion, reflecting the complexity of processes associated with the heterogeneous nature of real vegetation. Observed stem diameter distributions are utilized to highlight the sensitivity of existing models to this key length‐scale descriptor, leading to a recommendation that future models intended for application to real vegetation should be based on probabilistic descriptions of both stem diameters and stem spacings.
Longitudinal dispersion processes are often described by the Advection Dispersion Equation (ADE), which is analogous to Fick's law of diffusion, where the impulse response function of the spatial concentration distribution is assumed to be Gaussian. This paper assesses the validity of the assumption of a Gaussian impulse response function, using Residence Time Distributions (RTDs) obtained from new laboratory data. Measured up-and down-stream temporal concentration proÞles have been deconvolved to numerically infer RTDs for a range of turbulent, critical and laminar pipe ßows.It is shown that the Gaussian impulse response function provides a good estimate of the system's mixing characteristics for turbulent and critical ßows, and an empirical equation to estimate the dispersion coefficient for Reynolds Number, Re, between 3,000 and 20,000 is presented. For laminar ßow, here identified as Re < 3000, the RTDs do not conform to the Gaussian assumption due to insufficient time being available for the solute to become cross-sectionally well mixed. For this situation, which occurs commonly in water distribution networks, a theoretical RTD for laminar ßow that assumes no radial mixing is shown to provide a good approximation of the system's mixing characteristics at short times after injection.
Rising sea levels are causing more frequent flooding events in coastal areas and generate many issues for coastal communities such as loss of property or damages to infrastructures. To address this issue, this paper reviews measures currently in place and identifies possible control measures that can be implemented to aid preservation of coastlines in the future. Breakwaters present a unique opportunity to proactively address the impact of coastal flooding. However, there is currently a lack of research into combined hard and soft engineering techniques. To address the global need for developing sustainable solutions, three specific breakwater configurations were designed and experimentally compared in the hydraulic laboratory at Coventry University to assess their performance in reducing overtopping and the impact of waves, quantifying the effectiveness of each. The investigation confirmed that stepped configurations work effectively in high amplitudes waves, especially with the presence of a slope angle to aid wave reflection. These results provide a very valuable preliminary investigation into novel sustainable solutions incorporating both artificial and natural based strategies that could be considered by local and national authorities for the planning of future mitigation strategies to defend coastal areas from flooding and erosion.
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