An overview of Viscosity Solutions of Path-Dependent PDEs

This paper provides an overview of the recently developed notion of viscosity solutions of path-dependent partial di erential equations. We start by a quick review of the Crandall- Ishii notion of viscosity solutions, so as to motivate the relevance of our de nition in the path-dependent case. We focus on the wellposedness theory of such equations. In partic- ular, we provide a simple presentation of the current existence and uniqueness arguments in the semilinear case. We also review the stability property of this notion of solutions, in- cluding the adaptation of the Barles-Souganidis monotonic scheme approximation method. Our results rely crucially on the theory of optimal stopping under nonlinear expectation. In the dominated case, we provide a self-contained presentation of all required results. The fully nonlinear case is more involved and is addressed in [12]

Systematic determination of the mosaic structure of bacterial genomes: species backbone versus strain-specific loops

BACKGROUND: Public databases now contain multitude of complete bacterial genomes, including several genomes of the same species. The available data offers new opportunities to address questions about bacterial genome evolution, a task that requires reliable fine comparison data of closely related genomes. Recent analyses have shown, using pairwise whole genome alignments, that it is possible to segment bacterial genomes into a common conserved backbone and strain-specific sequences called loops. RESULTS: Here, we generalize this approach and propose a strategy that allows systematic and non-biased genome segmentation based on multiple genome alignments. Segmentation analyses, as applied to 13 different bacterial species, confirmed the feasibility of our approach to discern the 'mosaic' organization of bacterial genomes. Segmentation results are available through a Web interface permitting functional analysis, extraction and visualization of the backbone/loops structure of documented genomes. To illustrate the potential of this approach, we performed a precise analysis of the mosaic organization of three E. coli strains and functional characterization of the loops. CONCLUSION: The segmentation results including the backbone/loops structure of 13 bacterial species genomes are new and available for use by the scientific community at the URL:

Dry Markets and Superreplication Bounds of American Derivatives

This paper studies the impact of dry markets for underlying assets on the pricing of American derivatives, using a discrete time framework. Dry markets are characterized by the possibility of non-existence of trading at certain dates. Such non-existence may be deterministic or probabilistic. Using superreplicating strategies, we derive expectation representations for the range of arbitrage-free values of the dervatives. In the probabilistic case, if we consider an enlarged filtration induced by the price process and the market existence process, ordinary stopping times are required. If not, randomized stopping times are required. Several comparisons of the ranges obtained with the two market restrictions are performed. Finally, we conclude that arbitrage arguments are not enough to define the optimal exercise policy.N/

Fractional smoothness and applications in finance

This overview article concerns the notion of fractional smoothness of random variables of the form $g(X_T)$, where $X=(X_t)_{t\in [0,T]}$ is a certain diffusion process. We review the connection to the real interpolation theory, give examples and applications of this concept. The applications in stochastic finance mainly concern the analysis of discrete time hedging errors. We close the review by indicating some further developments.Comment: Chapter of AMAMEF book. 20 pages

30-Day Postoperative Morbidity of Emergency Surgery for Obstructive Right- and Left-Sided Colon Cancer in Obese Patients: A Multicenter Cohort Study of the French Surgical Association

BACKGROUND: Emergency surgery impairs postoperative outcomes in colorectal cancer patients. No study has assessed the relationship between obesity and postoperative results in this setting. OBJECTIVE: To compare the results of emergency surgery for obstructive colon cancer (OCC) in an obese patient population with those in overweight and normal weight patient groups. METHODS: From 2000 to 2015, patients undergoing emergency surgery for OCC in French surgical centers members of the French National Surgical Association were included. Three groups were defined: normal weight (body mass index [BMI] < 25.0 kg/m2), overweight (BMI 25.0-29.9 kg/m2), and obese (BMI ≥30.0 kg/m2). RESULTS: Of 1,241 patients, 329 (26.5%) were overweight and 143 (11.5%) were obese. Obese patients had significantly higher American society of anesthesiologists score, more cardiovascular comorbidity and more hemodynamic instability at presentation. Overall postoperative mortality and morbidity were 8 and 51%, respectively, with no difference between the 3 groups. For obese patients with left-sided OCC, stoma-related complications were significantly increased (8 vs. 5 vs. 15%, p = 0.02). CONCLUSION: Compared with lower BMI patients, obese patients with OCC had a more severe presentation at admission but similar surgical management. Obesity did not increase 30-day postoperative morbidity except stoma-related complications for those with left-sided OCC

Spatial Statistics of Visual Keypoints for Texture Recognition

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ASTERIX and 2.0 Knowledge Management : exploring the appropriation of 2.0 KMS via the Myth of the Gaulish village

International audienceKnowledge Management Systems (KMS) in companies have profoundly changed in recent years. They have become KMS 2.0 that aim to transform the firm and are driven by a new relationship to knowledge in line with 2.0 organisations. These 2.0 KMS have implemented modes of organisation that disrupt those that previously guided firms’ performance. This can sometimes lead to paradoxical organizational dysfunctions as witnessed by the difficulties faced by some traditionally hierarchical French companies. Through a case study of Constructor and a theoretical background on IS appropriation in organizations and myths in management, we show how the Asterix myth contributes to understanding how 2.0. KMS are appropriated in such companies. We find evidence of similarities regarding knowledge and Knowledge Management between the Asterix’ myth and the behaviours and practices concerning knowledge management within Constructor. As a result, the Asterix’ myth may be a relevant perspective for understanding the obstacles, advantages and appropriations of 2.0. KMS within French organizations