243 research outputs found
Cortex and deep grey matter have different sensitivities to hypoxia-hypotension and traumatic brain injury: a combined PtiO2 and microdialysis study in rats
O tratamento da polissemia e da homonímia nos learner's dictionaries: subsídios da semântica cognitiva para a disposição das acepções
Recommended from our members
Validation of reference tissue modelling for [11C]flumazenil positron emission tomography following head injury.
OBJECTIVE: [(11)C]Flumazenil ([(11)C]FMZ) positron emission tomography (PET) can be used as a measure of neuronal loss. The purpose of this study was to validate reference tissue kinetic modelling of [(11)C]FMZ PET within a group of patients with head injury. METHODS: Following earlier studies, the pons was used as the reference region. PET scans were performed on 16 controls and 11 patients at least 6 months following injury, each of whom also had arterial blood sampling to provide whole blood and metabolite-corrected plasma input functions. Regional non-displaceable binding potentials (BP(ND)) were calculated from five reference tissue models and compared to BP(ND) from arterial input models. For the patients, the regions included a peri-lesional region of interest (ROI). RESULTS: Total distribution volume of the pons was not significantly different between control and patient groups (P = 0.24). BP(ND) from all the reference tissue approaches correlated well with BP(ND) from the plasma input models for both controls (r (2) = 0.98-1.00; P < 0.001) and patients (r (2) = 0.99-1.00; P < 0.001). For the peri-lesional regions (n = 11 ROI values), the correlation was also high (r (2) = 0.91). CONCLUSIONS: These results indicate that reference tissue modelling with the pons as the reference region is valid for [(11)C]FMZ PET in head-injured patients at 6 months following injury within both normal appearing and peri-lesional brain regions
Is lazy abstraction a decision procedure for broadcast protocols?
Lazy abstraction builds up an abstract reachability tree by locally refining abstractions in order to eliminate spurious counterexamples in smaller and smaller subtrees. The method has proven useful to verify systems code. It is still open how good the method is as a decision procedure, i.e., whether the method terminates for already known decidable verification problems. In this paper, we answer the question positively for broadcast protocols and other infinite-state models in the class of so-called well-structured systems. This extends an existing result on systems with a finite bisimulation quotient
Boom: Taking Boolean Program Model Checking One Step Further
We present Boom, a comprehensive analysis tool for Boolean programs. We focus in this paper on model-checking non-recursive concurrent programs. Boom implements a recent variant of counter abstraction, where thread counters are used in a program-context aware way. While designed for bounded counters, this method also integrates well with the Karp-Miller tree construction for vector addition systems, resulting in a reachability engine for programs with unbounded thread creation. The concurrent version of Boom is implemented using BDDs and includes partial order reduction methods. Boom is intended for model checking system-level code via predicate abstraction. We present experimental results for the verification of Boolean device driver models
- …