Classificação das fraturas tóraco-lombares baseada em investigação por imagem: avaliação de 33 casos Classification of thoracolumbar spine fractures based on a complete imaging investigation in 33 patients

As fraturas das regiões torácica e lombar da coluna vertebral constituem amplo espectro de diferentes tipos de lesões resultantes de mecanismos fisiopatológicos distintos. A fim de se reduzir as controvérsias existentes a respeito da conduta destas lesões é necessária a utilização de uma classificação que permita a sua correta caracterização. Neste estudo avaliamos retrospectivamente 33 pacientes portadores de fraturas tóraco-lombares com o objetivo de categorizar e avaliar os fatores relacionados a esta patologia. O mecanismo de trauma mais freqüente foi queda de altura, presente em 24 casos. Na maioria dos pacientes (57,6%) as fraturas localizaram-se na transição tóraco-lombar (T12-L1) e o quadro neurológico mais freqüente foi o déficit sensitivo-motor completo abaixo da lesão, em 45,45% dos casos. A apresentação neurológica foi mais grave nos pacientes com lesões torácicas em relação às lesões lombares (teste de Fischer, p=0,039). Uma correlação positiva foi observada entre a severidade do quadro neurológico e a gravidade da lesão segundo a classificação de Magerl (r de Pearson=0,85, pThe thoracolumbar spine fractures constitute a wide spectrum of resultant lesions, with distinct injury mechanisms. In order to reduce the controversies concerning about the management of these fractures, a universally accepted classification is necessary. In this study we evaluated retrospectively 33 patients with thoracolumbar spine fracture, with the goal of categorize and evaluate the factors related to this pathology. A complete radiological investigation, complaining of plain radiography, computed tomography and magnetic ressonance imaging, was used to classify these fractures. Fall was the more common mechanism, present in 24 cases. In 57.6% of the patients, the fractures located at thoracolumbar transition (T12-L1) and the more frequent neurological presentation was total deficit, present in 45.45%. The neurological presentation was more serious in patients with thoracic lesions regarding lumbar lesions (Fischer's test, p=0.039). A positive correlation was observed between severity of the neurological presentation and gravity of the lesion according to Magerl's classification (Pearson's method, r=0.85, p<0.001). In conclusion, thoracolumbar spine fractures are serious lesions considering the initial neurological presentation; a wide and accurate classification, as we used, is necessary to describe these injuries and may help resolve some of the controversies concerning the management of these lesions

Reversing Unbounded Petri Nets

International audienceIn Petri nets, computation is performed by executing transitions. An effect-reverse of a given transition b is a transition that, when executed, undoes the effect of b. A transition b is reversible if it is possible to add enough effect-reverses of b so to always being able to undo its effect, without changing the set of reachable markings. This paper studies the transition reversibility problem: in a given Petri net, is a given transition b reversible? We show that, contrarily to what happens for the subclass of bounded Petri nets, the transition reversibility problem is in general undecidable. We show, however, that the same problem is decidable in relevant subclasses beyond bounded Petri nets, notably including all Petri nets which are cyclic, that is where the initial marking is reachable from any reachable marking. We finally show that some non-reversible Petri nets can be restructured, in particular by adding new places, so to make them reversible, while preserving their behaviour

Report on the model checking contest at Petri Nets 2011

Abstract. This article presents the results of the Model Checking Contest held within the SUMo 2011 workshop, a satellite event of Petri Nets 2011. This contest aimed at a fair and experimental evaluation of the performances of model checking techniques applied to Petri nets. The participating tools were compared on several examinations (state space generation, deadlock detection and evaluation of reachability formulæ) run on a set of common models (Place/Transition and Symmetric Petri nets). The collected data gave some hints about the way techniques can scale up depending on both examinations and the characteristics of the models. This paper also presents the lessons learned from the organizer’s point of view. It discusses the enhancements required for future editions of the Model Checking Contest event at the Petri Nets conference

Self-adaptive Model Checking, the Next Step?

International audienceModel checking is becoming a popular verification method that still suffers from combinatorial explosion when used on large industrial systems. Currently, experts can, in some cases, overcome this complexity by selecting appropriate modeling and verification techniques, as well as an adapted representation of the system. Unfortunately, this cannot yet be done automatically, thus hindering the use of model checking in industry. The objective of this paper is to sketch a way to tackle this problem by introducing self-adaptive model checking. This is a long term goal that could lead the community to elaborate a new generation of model checkers able to successfully push forwards the scale of the systems they can deal with

Foundations of reversible computation

Reversible computation allows computation to proceed not only in the standard, forward direction, but also backward, recovering past states. While reversible computation has attracted interest for its multiple applications, covering areas as different as low-power computing, simulation, robotics and debugging, such applications need to be supported by a clear understanding of the foundations of reversible computation. We report below on many threads of research in the area of foundations of reversible computing, giving particular emphasis to the results obtained in the framework of the European COST Action IC1405, entitled “Reversible Computation - Extending Horizons of Computing”, which took place in the years 2015–2019