A Process-Oriented Architecture for Complex System Modelling

A fine-grained massively-parallel process-oriented model of platelets (potentially artificial) within a blood vessel is presented. This is a CSP inspired design, expressed and implemented using the occam-pi language. It is part of the TUNA pilot study on nanite assemblers at the universities of York, Surrey and Kent. The aim for this model is to engineer emergent behaviour from the platelets, such that they respond to a wound in the blood vessel wall in a way similar to that found in the human body -- i.e. the formation of clots to stem blood flow from the wound and facilitate healing. An architecture for a three dimensional model (relying strongly on the dynamic and mobile capabilities of occam-pi) is given, along with mechanisms for visualisation and interaction. The biological accuracy of the current model is very approximate. However, its process-oriented nature enables simple refinement (through the addition of processes modelling different stimulants/inhibitors of the clotting reaction, different platelet types and other participating organelles) to greater and greater realism. Even with the current system, simple experiments are possible and have scientific interest (e.g. the effect of platelet density on the success of the clotting mechanism in stemming blood flow: too high or too low and the process fails). General principles for the design of large and complex system models are drawn. The described case study runs to millions of processes engaged in ever-changing communication topologies. It is free from deadlock, livelock, race hazards and starvation em by design, employing a small set of synchronisation patterns for which we have proven safety theorems

Zinc Deficiency and Fertilization.

2 p

Soil Acidity and Liming.

4 p

Does a nonlinear mating preference predict nonlinear benefits to offspring?: Avoiding bad mates to obtain good genes

Abstract only availableFemale Hyla versicolor (gray tree frogs) strongly prefer choosing mates with long or medium call lengths, avoiding the shorter callers. The development of their offspring is hypothesized to mirror this nonlinear preference, in that the long and medium caller progeny will develop at a similar rate that is faster than that of the short callers. Using past data, twenty-seven males with long, medium, and short call lengths were chosen and mated (in vitro) with random field-caught females. Five hundred and forty tadpoles were raised in individual containers. The tadpoles were subjected to high and low food treatments to test an environmental effect on their development. At three weeks, the tadpoles were weighed. These data were compared for the offspring of the long, medium, and short father's call according to food treatment as well as tadpole growth according to food treatment. Both the long calling and the medium calling progeny developed at a faster rate then the short calling progeny, but at a similar rate compared to each other. Tadpoles subjected to high food treatments developed at a faster rate than the low food treatment tadpoles. The dates of metamorphosis will also be recorded and later compared in the future. As the tadpoles of shorter calling fathers develop at a slower rate than the longer calling progeny, they are more at risk for environmental dangers and predation before they undergo metamorphosis. By researching female choices regarding length of calls and its effect on offspring development, we can examine how natural selection affects the evolution of female mating behavior.NSF grant to A. Welc

Wading in the gene pool: Female preference for long mating calls in gray tree frogs (Hyla versicolor)

Abstract only availableFemale gray tree frogs (Hyla versicolor) exhibit a clear preference for long mating calls. Moreover, the expression of this preference varies. The "good genes" model of sexual selection suggests that this is because females with extreme preferences mate with males with the most exaggerated traits, so their offspring will carry the genes for the extreme values of both trait and preference. Another possible explanation for variation in preference is that females in good physical condition, measured as body mass relative to length, will be better able to travel longer distances to find a longer calling male, resulting in a stronger call preference. We assessed the preference strength of lab-reared female frogs that are the offspring of short and long-calling fathers. We manipulated the condition of these females by placing them on a high and low feeding treatment. Frogs were tested in a soundproof acoustic testing chamber to determine preference strength, which was measured by using unequal playback levels of synthetic mating calls. We defined preference strength as the amount that the intensity of a long call can be reduced relative to the short call before the female prefers the shorter call. We found that preference strength was not significantly affected by father's call length, family, food treatment, or mass. Additionally, the response time for testing showed no relationship with either preference strength or mass. While there were no trends in the data, our sample size was small. Further testing with a larger sample size will give us a better idea of whether or not preference strength is affected by male call length or condition. Alternatively, female preference might be linked to variables we did not measure, such as age or past experience.Life Sciences Undergraduate Research Opportunity Progra

Phosphorus and Potassium Fertilization for Coastal Bermudagrass Hay Production in East Texas.

4 p

Zinc Deficiency and Fertilization.

2 p