Boundary Value Problem for an Oblique Paraxial Model of Light Propagation

We study the Schr\"odinger equation which comes from the paraxial approximation of the Helmholtz equation in the case where the direction of propagation is tilted with respect to the boundary of the domain. This model has been proposed in (Doumic, Golse, Sentis, CRAS, 2003). Our primary interest here is in the boundary conditions successively in a half-plane, then in a quadrant of R2. The half-plane problem has been used in (Doumic, Duboc, Golse, Sentis, JCP, to appear) to build a numerical method, which has been introduced in the HERA plateform of CEA

Une perspective de droit comparé

L'idée d'énoncer le droit dans un code constitue un projet ambitieux. L'évolution du temps a démontré les insuffisances du code actuel et le rôle fondamental joué par la jurisprudence. Avant d'aller plus loin dans le processus législatif, il faut se poser certaines questions indispensables. Faut-il toujours codifier dans le secteur des obligations et, si oui, que faut-il codifier ? Le législateur ne peut prétendre poser des règles précises en toutes matières, particulièrement dans le domaine des contrats où la volonté des parties doit s'exprimer. Par une démarche comparatiste, on aborde d'une part les avantages et inconvénients de la codification elle-même; d'autre part on s'interroge sur le prix à payer pour la sauvegarde de la liberté contractuelleThe idea of expressing law in the form of a code is an ambitious project. The passage of time has demonstrated the insufficiencies of the present Code and the basic part played by case-law. Before going further with the legislative process, certain basic questions must be raised. Is it still appropriate to codify in the area of obligations and, if so, what must be codified ? The legislator cannot lay down specific rules in all areas, especially in the field of contracts where the will of the parties must be expressed. By using a comparative approach, the author addresses the advantages and disadvantages of codification as such and raises the question of the price to be paid for maintaining contractual freedom

Dynamic modelling of hepatitis C virus transmission among people who inject drugs: a methodological review

Equipment sharing among people who inject drugs (PWID) is a key risk factor in infection by hepatitis C virus (HCV). Both the effectiveness and cost-effectiveness of interventions aimed at reducing HCV transmission in this population (such as opioid substitution therapy, needle exchange programs or improved treatment) are difficult to evaluate using field surveys. Ethical issues and complicated access to the PWID population make it difficult to gather epidemiological data. In this context, mathematical modelling of HCV transmission is a useful alternative for comparing the cost and effectiveness of various interventions. Several models have been developed in the past few years. They are often based on strong hypotheses concerning the population structure. This review presents compartmental and individual-based models in order to underline their strengths and limits in the context of HCV infection among PWID. The final section discusses the main results of the papers

Impact of a treatment as prevention strategy on hepatitis C virus transmission and on morbidity in people who inject drugs

Background: Highly effective direct-acting antiviral (DAA) regimens (90% efficacy) are becoming available for hepatitis C virus (HCV) treatment. This therapeutic revolution leads us to consider possibility of eradicating the virus. However, for this, an effective cascade of care is required. Methods: In the context of the incoming DAAs, we used a dynamic individual-based model including a model of the people who inject drugs (PWID) social network to simulate the impact of improved testing, linkage to care, and adherence to treatment, and of modified treatment recommendation on the transmission and on the morbidity of HCV in PWID in France. Results: Under the current incidence and cascade of care, with treatment initiated at fibrosis stage $\ge$F2, the HCV prevalence decreased from 42.8% to 24.9% [95% confidence interval 24.8%--24.9%] after 10 years. Changing treatment initiation criteria to treat from F0 was the only intervention leading to a substantial additional decrease in the prevalence, which fell to 11.6% [11.6%--11.7%] at 10 years. Combining this change with improved testing, linkage to care, and adherence to treatment decreased HCV prevalence to 7% [7%--7.1%] at 10 years and avoided 15.3% [14.0%-16.6%] and 29.0% [27.9%--30.1%] of cirrhosis complications over 10 and 40 years respectively. Conclusion: A high decrease in viral transmission occurs only when treatment is initiated before liver disease progresses to severe stages, suggesting that systematic treatment in PWID, where incidence remains high, would be beneficial. However, eradication will be difficult to achieve

Sequestering CO2 by Mineralization into Useful Nesquehonite-Based Products

The work described here was supported financially by GORD, the Gulf Organisation for Research and Development, based in Doha, Qatar. It forms part of the “Green Concrete” project at the University of Aberdeen.Peer reviewedPublisher PD

Targeting breast cancer stem cells: fishing season open!

Studies describing the tumor as a hierarchically organized cell population have changed the classical oncogenesis view and propose new therapeutic strategies. Cancer stem cells (CSCs) are thought to sustain tumor initiation/maintenance, therapy resistance, and systemic metastases. Targeting this tumor cell population is crucial to achieve a true cancer cure. A large research effort is now aiming to develop drugs targeting CSCs, based either on a priori understanding of key pathways regulating CSC biology or on high-throughput screening to identify novel targets and compounds

Using colour semiotics to explore colour meanings

Purpose The impact of colour is acknowledged within the marketing field. However, research on colour communication is limited, with most prior studies focusing on pre-defined meanings or colour associations. The aim of this study is to reveal insights into colour meaning and propose an alternative view to understanding colour communication. Design/methodology/approach The study takes a conceptual approach and proposes Peircean semiotics to understand colour communication. The proposed framework is applied to analyse a set of colour meanings detected by prior colour research. Findings The study elucidates the underlying mechanism of how colour is read and interpreted in various marketing activities, and how meaning is conveyed. This study addresses this mechanism by identifying colour semantics and colour as a symbolic, iconic and indexical sign. Originality/value By elaborating on how colours convey meanings and the mechanism that explains such meanings, this study demonstrates that colour meaning is far more than mere association. The study contributes to the current knowledge of colour by facilitating a deeper understanding of how consumers interpret representations of single visual cues expressed in various contexts.fi=vertaisarvioitu|en=peerReviewed

Eigenelements of a General Aggregation-Fragmentation Model

We consider a linear integro-differential equation which arises to describe both aggregation-fragmentation processes and cell division. We prove the existence of a solution (\lb,\U,\phi) to the related eigenproblem. Such eigenelements are useful to study the long time asymptotic behaviour of solutions as well as the steady states when the equation is coupled with an ODE. Our study concerns a non-constant transport term that can vanish at $x=0,$ since it seems to be relevant to describe some biological processes like proteins aggregation. Non lower-bounded transport terms bring difficulties to find $a\ priori$ estimates. All the work of this paper is to solve this problem using weighted-norms

Numerical Solution of an Inverse Problem in Size-Structured Population Dynamics

We consider a size-structured model for cell division and address the question of determining the division (birth) rate from the measured stable size distribution of the population. We propose a new regularization technique based on a filtering approach. We prove convergence of the algorithm and validate the theoretical results by implementing numerical simulations, based on classical techniques. We compare the results for direct and inverse problems, for the filtering method and for the quasi-reversibility method proposed in [Perthame-Zubelli]