Conditioning diffusions with respect to partial observations

In this paper, we prove a result of equivalence in law between a diffusion conditioned with respect to partial observations and an auxiliary process. By partial observations we mean coordinates (or linear transformation) of the process at a finite collection of deterministic times. Apart from the theoritical interest, this result allows to simulate the conditioned diffusion through Monte Carlo's method, using the fact that the auxiliary process is easy to simulate

Characterizing, Explaining and Valuing the Effective Use of an IT Artefact: A Field Study of Performance Management Information Systems in SMEs

Calls have been made for IS research to shift from the study of the use of IT artefacts to the study of their effective use. In seeking to provide added validity and relevance to the concept of effective use, we apply Burton-Jones and Grange’s theoretical framework to study the dimensions, contextual drivers and benefits of effective use. This is done through a field study of performance management information systems (PMIS) as used in 16 small and medium-sized enterprises (SMEs). In characterizing, contextualizing and valuing the effective use of a mission-critical IT artefact such as a PMIS, our results provide further empirical grounding and understanding of this complex yet under researched concept

Familles infinies de boucles incassables

Une boucle incassable est une boucle ne contenant aucune sous-boucle propre. Ce mémoire propose la construction de quatre familles de boucles incassables caractérisées par leur commutativité et par leur groupe de multiplication. La première famille est tout simplement une famille de boucles incassables de tout ordre. La seconde famille est une famille de boucles incassables commutatives d'ordre premier dont le groupe de multiplication est le groupe symétrique. La troisième famille élargit la seconde à tous les ordres impairs. La dernière famille est une famille de boucles incassables commutatives d'ordre impair dont le groupe de multiplication est le groupe alterné

Impact of COVID-19 on the prescribing pattern of oral anticoagulants for atrial fibrillation after cardiac surgery

Background: Because of logistic challenges associated with the COVID-19 pandemic, direct oral anticoagulants (DOAC) were favored over warfarin in patients presenting postoperative atrial fibrillation (AF) after cardiac surgery in our institution. Considering the limited evidence supporting the use of DOAC in this context, we sought to evaluate the safety and efficacy of this practice change. Methods: A retrospective study was performed with patients from the Quebec City metropolitan area who were hospitalized at the Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval following cardiac surgery and who required oral anticoagulant (OAC) for postoperative AF. The primary objective was to compare the pre- and peri-COVID-19 period for OAC prescribing patterns and the incidence of thrombotic and bleeding events at 3 months post-surgery. The secondary objective was to compare DOAC to warfarin in terms of thrombotic events and bleeding events. Results: A total of 233 patients were included, 142 from the pre-COVID-19 and 91 from the peri-COVID-19 period, respectively. Both groups had equivalent proportions of preoperative AF (48%) and new-onset postoperative AF (52%). The proportion of patients treated with a DOAC increased from 13% pre-COVID-19 to 82% peri-COVID-19. This change in practice was not associated with a significant difference in the incidence of thrombotic or bleeding events 3 months postoperatively. However, compared to DOAC, warfarin was associated with a higher incidence of major bleeding. Only 1 thrombotic event was reported with warfarin, and none were reported with DOAC. Conclusion: This study suggests that DOAC are an effective and safe alternative to warfarin to treat postoperative AF after cardiac surgery and that this practice can be safely maintained

Anomaly Characterization in Large Scale Networks

International audienceThe context of this work is the online characterization of anomalies in large scale systems. In particular, we address the following question: Given two successive configurations of the system, can we distinguish massive anomalies from isolated ones, the former ones impacting a large number of nodes while the second ones affect solely a small number of them, or even a single one? The rationale of this question is twofold. First, from a theoretical point of view, we characterize anomalies with respect to their neighborhood, and we show that there are anomaly scenarios for which isolated and massive anomalies are indistinguishable from an global observer point of view. We then relax the definition of this problem by introducing \emph{unresolved} configurations, and exhibit necessary and sufficient conditions that allows any node to determine the type of anomaly it has been impacted by. This condition only depends on the close neighborhood of each node and thus is locally computable. We present an algorithm that implements this condition. We show through extensive simulations the performance of our algorithm. From a practical point of view, distinguishing isolated anomalies from massive ones is of utmost importance for networks providers. For instance, regarding Internet service providers that operate millions of home gateways, it would be very interesting to have procedures that allow gateways to self distinguish whether their dysfunction is caused by network-level anomalies or by their own hardware or software, and to notify the service provider only in the latter case

Transcutaneous electrical nerve stimulation (TENS): towards the development of a clinic-friendly method for the evaluation of excitatory and inhibitory pain mechanisms

Abstract: Background: Temporal summation and conditioned pain modulation (CPM) can be measured using a thermode and cold pressor test (CPTest). Unfortunately, these complex and expensive tools are ill-suited for routine clinical assessments. Aims: We aimed to compare the temporal summation and CPM obtained with the thermode + CPTest paradigm to those obtained with a novel paradigm using transcutaneous electrical nerve stimulation (TENS). Methods: We assessed temporal summation and CPM in 29 healthy participants, using two paradigms (random order): TENS, and thermode + CPTest. In the TENS paradigm, both the conditioning stimulus (CS) and the test stimulus (TS) were delivered using TENS; in the thermode + CPTest paradigm, the CS consisted of a CPTest and the TS was delivered using a thermode. We compared the average temporal summation and CPM evoked by the two paradigms. Results: Average temporal summation was similar for both modalities (P = 0.90), and the number of participants showing temporal summation was similar in both paradigms (19 with thermode vs. 18 with TENS; P = 1.00). Average CPM response was larger following the thermode + CPTest than following the TENS (P = 0.005), and more participants showed CPM with the thermode + CPTest paradigm compared to the TENS paradigm (24 vs. 14; P = 0.01). Conclusions: Both paradigms were roughly equivalent in the ability to evoke temporal summation (although response to one modality did not predict response to the other), but the TENS paradigm appeared to be less apt to induce a CPM response than the thermode + CPTest paradigm.Contexte: La sommation temporelle et la modulation de la douleur conditionnée (MDC) peuvent être mesurées à l’aide d’une thermode et d’un test au froid. Malheureusement, ces tests complexes et coûteux sont mal adaptés aux évaluations cliniques de routine. Objectifs: Nous avons cherché à comparer la sommation temporelle et la modulation de la douleur conditionnée obtenues avec le paradigme thermode + test au froid à ceux obtenus avec un nouveau paradigme utilisant la neurostimulation électrique transcutanée (TENS). Méthodes: Nous avons évalué la sommation temporelle et la modulation de la douleur conditionnée chez 29 participants en bonne santé, en utilisant les deux paradigmes (ordre aléatoire) : TENS, et thermode + test au froid. Dans le paradigme TENS, Le stimulus de conditionnement et le stimulus d’essai ont été transmis à l’aide de la neurostimulation électrique transcutanée ; dans le paradigme thermode + test au froid, le stimulus de conditionnement consistait en un test au froid et le stimulus d’essai était transmis à l’aide d’une thermode. Nous avons comparé la sommation temporelle et la modulation de la douleur conditionnée moyennes évoqués par les deux paradigmes. Résultats: La sommation temporelle moyenne était similaire pour les deux modalités (P = 0,90), et le nombre de participants ayant montré une sommation temporelle étaient similaires dans les deux paradigmes (19 avec la thermode contre 18 avec la TENS; P = 1,00). La réponse moyenne de modulation de la douleur conditionnée était plus importante après la thermode + test au froid qu’après la neurostimulation électrique transcutanée (P = 0,005), et un plus grand nombre de participants ont montré une modulation de la douleur conditionnée avec la thermode + test au froid par rapport au paradigme TENS (24 contre 14 ; P = 0,01)

Anomaly Characterization Problems

National audienceThe context of this work is the online characterization of anomalies in large scale systems. In particular, we address the following question: Given two successive configurations of the system, can we distinguish massive anomalies from isolated ones, the former ones impacting a large number of nodes while the second ones affect solely a small number of them, or even a single one? The rationale of this question is twofold. First, from a theoretical point of view, we characterize anomalies with respect to their neighborhood, and we show that there are anomaly scenarios for which isolated and massive anomalies are indistinguishable from an omniscient observer point of view. We then relax this problem by introducing unresolved configurations, and exhibit necessary and sufficient conditions that allow any node to determine the type of anomaly it has been impacted by. This condition only depends on the close neighborhood of each node and thus is locally computable. From a practical point of view, distinguishing isolated anomalies from massive ones is of utmost importance for networks providers. For instance, Internet service providers (ISPs) would be interested to deploy procedures that allow gateways to self distinguish whether their dysfunction is caused by network-level anomalies or by their own hardware or software, and to notify the ISP only in the latter case. \keywords{Network monitoring, anomaly detection, diagnosis

Anomaly Characterization Problems

National audienceThe context of this work is the online characterization of anomalies in large scale systems. In particular, we address the following question: Given two successive configurations of the system, can we distinguish massive anomalies from isolated ones, the former ones impacting a large number of nodes while the second ones affect solely a small number of them, or even a single one? The rationale of this question is twofold. First, from a theoretical point of view, we characterize anomalies with respect to their neighborhood, and we show that there are anomaly scenarios for which isolated and massive anomalies are indistinguishable from an omniscient observer point of view. We then relax this problem by introducing unresolved configurations, and exhibit necessary and sufficient conditions that allow any node to determine the type of anomaly it has been impacted by. This condition only depends on the close neighborhood of each node and thus is locally computable. From a practical point of view, distinguishing isolated anomalies from massive ones is of utmost importance for networks providers. For instance, Internet service providers (ISPs) would be interested to deploy procedures that allow gateways to self distinguish whether their dysfunction is caused by network-level anomalies or by their own hardware or software, and to notify the ISP only in the latter case. \keywords{Network monitoring, anomaly detection, diagnosis