Raviart-Thomas finite elements of Petrov-Galerkin type

The mixed finite element method for the Poisson problem with the Raviart-Thomas elements of low-level can be interpreted as a finite volume method with a non-local gradient. In this contribution, we propose a variant of Petrov-Galerkin type for this problem to ensure a local computation of the gradient at the interfaces of the elements. The shape functions are the Raviart-Thomas finite elements. Our goal is to define test functions that are in duality with these shape functions: Precisely, the shape and test functions will be asked to satisfy a L2-orthogonality property. The general theory of Babu\v{s}ka brings necessary and sufficient stability conditions for a Petrov-Galerkin mixed problem to be convergent. We propose specific constraints for the dual test functions in order to ensure stability. With this choice, we prove that the mixed Petrov-Galerkin scheme is identical to the four point finite volumes scheme of Herbin, and to the mass lumping approach developed by Baranger, Maitre and Oudin. Finally, we construct a family of dual test functions that satisfy the stability conditions. Convergence is proven with the usual techniques of mixed finite elements

Genetic risk variants in intestinal inflammatory disorders

PhDThis thesis includes work on the genetics of intestinal inflammatory disorders, concentrating on coeliac disease and Crohn’s disease. It explores how common genetic variants influence risk of complex phenotypes including immunological intolerance to gluten (coeliac disease) and intolerance to therapeutic agents (azathioprine and mercaptopurine) used in the treatment of intestinal inflammatory diseases. Finally it presents work aiming to move from genetic associations with complex phenotypes to understanding of how these variants modulate immunological processes. Results of a large genome wide association study that identified more than 13 new genetic risk regions influencing susceptibility to coeliac disease are presented. Results of a genome wide association study of azathioprine and 6-mercaptopurine-induced pancreatitis in inflammatory bowel disease-affected individuals are presented. Finally, a cell cytokine release assay for the prostaglandin EP4 receptor was developed, with a view to investigating how SNPs associated with Crohn’s disease in the 5p13.1 region influence EP4 receptor signalling and contribute to disease pathogenesis. This work highlights some of the challenges in moving from SNP-disease associations identified in GWASs to understanding how genetic variants change biological processes

Integer and fractional charge Lorentzian voltage pulses analyzed in the frame of Photon-assisted Shot Noise

The periodic injection $n$ of electrons in a quantum conductor using periodic voltage pulses applied on a contact is studied in the energy and time-domain using shot noise computation in order to make comparison with experiments. We particularly consider the case of periodic Lorentzian voltage pulses. When carrying integer charge, they are known to provide electronic states with a minimal number of excitations, while other type of pulses are all accompanied by an extra neutral cloud of electron and hole excitations. This paper focuses on the low frequency shot noise which arises when the pulse excitations are partitioned by a single scatterer in the framework of the Photo Assisted Shot Noise (PASN) theory. As a unique tool to count the number of excitations carried per pulse, shot noise reveals that pulses of arbitrary shape and arbitrary charge show a marked minimum when the charge is integer. Shot noise spectroscopy is also considered to perform energy-domain characterization of the charge pulses. In particular it reveals the striking asymmetrical spectrum of Lorentzian pulses. Finally, time-domain information is obtained from Hong Ou Mandel like noise correlations when two trains of pulses generated on opposite contacts collide on the scatterer. As a function of the time delay between pulse trains, the noise is shown to measure the electron wavepacket autocorrelation function for integer Lorentzian thanks to electron antibunching. In order to make contact with recent experiments all the calculations are made at zero and finite temperature

Uncommon external abdominal oblique muscle strain in a professional soccer player: a case report

BACKGROUND: This is the first report of external abdominal oblique muscle injury occurring in a professional soccer player. CASE PRESENTATION: A 28-year-old Caucasian professional soccer player presented after experiencing a popping sensation associated with strong parietal pain localized between the left 11th and 12th ribs. Ultrasound examination revealed a collection of fluid under the 11th rib, suggesting injury of the left external oblique muscle. Platelet-rich plasma treatment was administered and the soccer player returned to competition on the 21st day after treatment. CONCLUSION: This rare injury results from a sudden intrinsic eccentric contraction of the internal oblique muscle while in a stretched position. Ultrasound can help to confirm the diagnosis and to monitor clinical follow-up. Platelet-rich plasma treatment could aid recovery in high-level athletes

Instrument far measuring terrestrial heat flow through the ocean floor

Terrestrial heat flow through the ocean floor is determined by measuring the temperature gradient and thermal conductivity in the upper few meters of sediment with an instrument lowered on hydrographic wire. The chief novel feature of the device is that the thermal conductivity is measured in situ simultaneously with the temperature gradient instead of in a cored specimen of sediment in the laboratory