Longitudinal Voxel-based morphometry with unified segmentation: evaluation on simulated Alzheimer’s disease

The goal of this work is to evaluate Voxel-Based Morphometry and three longitudinally-tailored methods of VBM.We use a cohort of simulated images produced by deforming original scans using a Finite Element Method, guided to emulate Alzheimer-like changes. The simulated images provide quite realistic data with a known pattern of spatial atrophy, with which VBM’s findings can be meaningfully compared. We believe this is the first evaluation of VBM for which anatomically-plausible ‘gold-standard’ results are available. The three longitudinal VBM methods have been implemented within the unified segmentation framework of SPM5; one of the techniques is a newly developed procedure, which shows promising potential

Two-component radiation model of the sonoluminescing bubble

Based on the experimental data from Weninger, Putterman & Barber, Phys. Rev. (E), 54, R2205 (1996), we offer an alternative interpretation of their experimetal results. A model of sonoluminescing bubble which proposes that the electromagnetic radiation originates from two sources: the isotropic black body or bramsstrahlung emitting core and dipole radiation-emitting shell of accelerated electrons driven by the liquid-bubble interface is outlined.Comment: 5 pages Revtex, submitted to Phys. Rev.

The National Estuary Program

Estuaries are waterways where fresh water from rivers mixes with salt water from the ocean. They sustain an abundance of finfish, shellfish and marine microscopic life as well as valuable habitats such as marshes and underwater grass beds. The definition of estuaries may not be widely known, but they are one of the most commonly used natural features on earth. Estuaries, their shores and adjacent drainage basins have always been popular sites for commercial, recreational, industrial and agricultural activities. The number of people and businesses attracted to estuaries by their recreation, commerce and aesthetics is increasing. Almost fifty percent of the population of the United States lives within fifty miles of the coast. The aquatic life that estuaries support is affected by these growing populations and their use of estuarine resources. Pollution and physical alteration have taken their toll on a number of estuaries and threatens others

A mathematical model of low-head oxygenators

AbstractA mathematical model is presented that predicts the performance of low-head oxygenators (LHO). Experimentally determined values of G20 for a single hole in a flooded orifice plate were used as the basis to develop a mathematical model that can be used to predict LHO performance under a variety of design and operating conditions. Model predictions were compared to two published studies. The model predicted the published data for dissolved oxygen levels in the departing effluent within 2–3%, oxygen absorption efficiencies within 5–6%, and total gas pressures within 1%. The mathematical model is thoroughly developed including an analysis of numerical stability and necessary restrictions to assure stability and accuracy. Convergence based solely upon effluent values was not sufficient to produce accurate results, but required additional criteria of requiring a minimum number of chamber flushings prior to convergence checking. The model was used to demonstrate its utility in predicting the effects of G/L ratio on gas absorption efficiency, effluent gas conditions and the effects of number of LHO chambers used. This model allows the designer or operator of an LHO to easily make design and operational decisions by modifying the input parameters and observing the exit conditions and performance indicators