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The superior mesenteric ganglion (S.m.g.), a sympathetic prevertebral ganglion, is an integrating center for gastrointestinal reflexes. Many details of its structure are still lacking. In the present study, mouse S.m.g. neurons were studied by light, electron, and confocal microscopy. Neurons had an average of 5-6 primary dendrites. Total dendritic length averaged 963 microns. Confocal microscopy and three-dimensional reconstructed images revealed cell body surface features, precise location where axons and dendrites emerged from it, cell body size, and extent of dendritic projection in three axes. Cell body diameter and dendritic projections were less in the dorsoventral than in the rostrocaudal or mediolateral axes. Cell body surface area and volume averaged 4,271 microns 2 and 4,908 microns 3, respectively. Dendritic surface areas and volumes were 5-6 times larger. Two main neuron types (projecting caudally or rostrally) were distinguished. The former were found throughout the S.m.g., whereas the latter were found only in the cephalad region, comprising about 40% of neurons found there. Rostrally projecting neurons had fewer primary dendrites, fewer total dendritic branches, and shorter total dendritic length than caudally projecting neurons. There were regional differences in percentage of neurons responding to electrical stimulation of left or right hypogastric, lumbar colonic, or left splanchnic nerves but not in nerve fibers connecting the S.m.g. and celiac ganglion. A greater percentage of caudally than rostrally projecting cephalad neurons responded to stimulation of any nerve trunk. These results indicate that the mouse S.m.g. contains at least two distinct types of neurons that differ in their morphology and their source of preganglionic synaptic input.

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Abstract-Designing and verifying distributed protocols in a multi-rate asynchronous system is, in general, extremely difficult when the distributed computations require consistent input views, consistent actions and synchronized state transitions. In this paper, we address this problem and introduce a formal, complexity-reducing architectural pattern, called Multi-rate PALS system, to support virtual synchronization in multi-rate distributed computations. The pattern supports a component to be virtually synchronized with other components in different instantiations of this pattern. We present an application of a hierarchical control system to show that the composition of these instantiations can be used to achieve desired systemlevel properties, such as distributed consistency and distributed coordination. We verify the logical synchronization guarantee of this pattern which holds as long as the pattern assumptions are satisfied. We also discuss the correctness analysis necessary to validate these assumptions and provide a tool support to perform this analysis automatically on the AADL models.

Modern defense systems are complex distributed software systems implemented over heterogeneous and constantly evolving hardware and software platforms. Distributed agreement protocols are often developed exploiting the fact that their systems are quasi-synchronous, where even though the clocks of the different nodes are not synchronized, they all run at the same rate, or multiples of the same rate, modulo their drift and jitter.This paper describes an effort to provide systems designers and engineers with an intuitive modeling environment that allows them to specify the highlevel architecture and synchronization logic of quasisynchronous systems using widely available systemsengineering notations and tools. To this end, a translator was developed that translates system architectural models specified in a subset of SysML into the Architectural Analysis and Description Language (AADL). Translators were also developed that translate the AADL models into the input language of the Uppaal and Kind model checkers.The Uppaal model checker. supports the modeling, verification, and validation of real-time systems modeled as a network of timed automata. This paper focuses on the challenges encountered in translating from AADL to Uppaal, and illustrates the overall approach with a common avionics example: the Pilot Flying System.