Positron emission tomography (PET) can image a wide variety of functional and physiological parameters in vivo using different radiotracers. As more is learned about the molecular basis for disease and treatment, the potential value of molecular imaging for characterizing and monitoring disease status has increased. Characterizing multiple aspects of tumor physiology by imaging multiple PET tra...

A Prolog tracer is essentially a Prolog interpreter extended to provide features, such as retry, fail, leap, skip, and quasi-skip, to trace the computational ow of a program. This paper describes how a Prolog tracer may be built by stepwise enhancement. Using this method, rst a collection of partial-tracers are developed, each partial-tracer providing only a part of the tracer's functionality. ...

[1] A two-dimensional numerical model is used to study the diapycnal flow through a tidal front with passive tracers. In a basic numerical experiment a passive tracer is released into the bottom water at the offshore edge of a tidal front, and it subsequently moves on-bank with a velocity that decreases with time. This qualitatively agrees with a recent field experiment using a dye tracer on Ge...

Ray tracing as an image synthesis technique has enjoyed immense success. Learning about the algorithms is much easier through implementation for any technique, in the case of ray tracing one aspect learned is that it is simple to implement. Moreover, implementing a ray tracer goes a long way as a learning aid for much of computer graphics. I will discuss the very basics of implementing a ray tr...

The average concentration of a passive scalar advected from a point source by a multivariate normal velocity field is shown to deviate from a Gaussian profile. The flatness (kurtosis) is calculated using an asymptotic series expansion valid for velocity fields with short correlation times or weak space dependence. An explicit formula for the excess flatness at first order demonstrates maximum d...

In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at r...

the hydraulic characteristic of an up-flow anaerobic sludge blanket fixed film (uasb-ff) were studied by changing two important hydraulic factors that can impact significantly on the hydraulic regime of the uasb-ff bioreactor: the up-flow velocity (vup) and biogas production rate (qg). the analysis of the reactor hydraulic performance was performed by studying hydraulic residence time distribut...

153 Abstract: The location of extrinsic afferent and efferent neurons projecting to the rat gastrointestinal tract were mapped using the retrograde tracer, True Blue (TB). Injection of retrograde tracer, TB into stomach, proximal colon and distal colon resulted in labelled cells in the dorsal root ganglia. Cells were also labelled in the nodose ganglia following injection of tracer into stomach...