Shallow Linear Action Graphs and their Embeddings

Action calculi, which generalise process calculi such as Petri nets, π-calculusand ambient calculus, have been presented in terms of action graphs. We here offer linear action graphs as a primitive basis for action calculi. This paper presents the category of embeddings of undirected linear action graphs without nesting, using a novel form of graphical reasoning which simplifies some otherwise complex manipulations in regular algebra. The results are adapted in a few lines to directed graphs. This work is part of a long-term search for a uniform behavioural theory for process calculi. Received October 2000 / Accepted in revised form April 2001     

Bayesian channel equalisation and robust features for speechrecognition

The use of a speech recognition system with telephone channel environments, or different microphones, requires channel equalisation. In speech recognition, the speech model provides a bank of statistical information that can be used in the channel identification and equalisation process. The authors consider HMM-based channel equalisation, and present results demonstrating that substantial improvement can be obtained through the equalisation process. An alternative method, for speech recognition, is to use a feature set which is more robust to channel distortion. Channel distortions result in an amplitude tilt of the speech cepstrum, and therefore differential cepstral features provide a measure of immunity to channel distortions. In particular the cepstral-time feature matrix, in addition to providing a framework for representing speech dynamics, can be made robust to channel distortions. The authors present results demonstrating that a major advantage of cepstral-time matrices is their channel insensitive character     

A comparative study of human skin thermal response to sapphirecontact and cryogen spray cooling

Surface cooling, in conjunction with various thermally mediated therapeutic procedures, can provide a means to protect superficial tissues from injury while achieving destruction of deeper targeted structures. We have investigated the thermal response of in-vivo human skin to: (1) contact cooling with a sapphire window (6-12°C); and (2) spray cooling with a freon substitute cryogen [tetrafluoroethane; boiling point ≈-26°C at 1 atmospheric pressure (atm)]. Measurements utilizing infrared radiometry show surface temperature reductions from 30°C to 14-19°C are obtained within approximately is in response to sapphire contact cooling. Surface temperature reductions to values between 5°C and -9°C are obtained in response to 20-100-ms cryogen spurts. Computational results, based on fitting the measured radiometric surface temperature to estimate heat transfer parameters, show: (1) temperature reductions remain localized to approximately 200 μm of superficial tissue; and (2) values of heat flux and total energy removed per unit skin surface area at least doubled when using cryogen spray cooling     

A collaborative study on the determination of available lysine in feeding stuffs

The methods of Carpenter¹ and Roach, Sanderson and Williams² for the determination of available lysine have been compared in two collaborative studies involving eight laboratories. The feeding stuffs used were: fish meal and groundnut meal in Trial 1 and soya bean meal, sunflower meal, a commercial mixed feed and wheat meal in Trial 2. There was no statistically significant difference between the two methods in terms of their overall means for any of the materials studied, though for mixed feed the values by Carpenter's method tended to be smaller. Inter-laboratory standard deviations for available lysine were generally greater by Carpenter's method, but significance was established only in the case of wheat. - Some of the problems encountered in both methods are discussed.     

Liver lipid alterations in rats fed arginine deficient diets

Arginine deficiency is associated with a marked increase in liver lipids in the rat. Triglyceride accumulation accounts for most of the fatty infiltration. Cholesterol concentration per gram of liver increased approximately 280% above control rats receiving dietary arginine. The percentage of phospholipids was significantly decreased in the arginine-deficient rat liver compared to controls. The fatty acid composition revealed a significant reduction in the percentage of palmitic, palmitoleic, oleic, and linoleic acids. However, both stearic and arachidonic acids were increased approximately 250 and 160%, respectively, in arginine-deficient livers compared to controls. Arginine deficiency in the rat causes a marked alteration in lipid metabolism similar to that observed with orotic acid feeding. The similarities of arginine deficiency and orotic acid feeding are discussed.     

Calculi for interaction

Action structures have previously been proposed as an algebra for both the syntax and the semantics of interactive computation. Here, a class of concrete action structures called action calculi is identified, which can serve as a non-linear syntax for a wide variety of models of interactive behaviour. Each action in an action calculus is represented as an assembly of molecules; the syntactic binding of names is the means by which molecules are bound together. A graphical form, action graphs, is used to aid presentation. One action calculus differs from another only in its generators, called controls. Action calculi generalise a previously defined action structure for the -calculus. Several extensions to are given as action calculi, giving essentially the same power as the -calculus. An action calculus is also given for the typed -calculus, and for Petri nets parametrized on their places and transitions. An equational characterization of action calculi is given: each action calculus is the quotient of a term algebra by certain equations. The terms are generated by a set of operators, including those basic to all action structures as well as the controls specific to ; the equations are the basic axioms of action structures together with four additional axiom schemata. Received May 12, 1995 / August 7, 1995