Periodicity Disruption of a Model Quasibiennial Oscillation of Equatorial Winds.

The quasibiennial oscillation (QBO) of equatorial winds on Earth is the clearest example of the spontaneous emergence of a periodic phenomenon in geophysical fluids. In recent years, observations have revealed intriguing disruptions of this regular behavior, and different QBO-like regimes have been reported in a variety of systems. Here, we show that part of the variability in mean-flow reversals can be attributed to the intrinsic dynamics of wave-mean-flow interactions in stratified fluids. Using a constant-in-time monochromatic wave forcing, bifurcation diagrams are mapped for a hierarchy of simplified models of the QBO, ranging from a quasilinear model to fully nonlinear simulations. The existence of new bifurcations associated with faster and shallower flow reversals, as well as a quasiperiodic route to chaos are reported in these models. The possibility for periodicity disruptions is investigated by probing the resilience of regular wind reversals to external perturbations.

[Can medical oncologists talk about cure to their patient after localized breast cancer treatment?] / Pouvons-nous à l'heure actuelle parler de guérison après le traitement d'un cancer du sein localisé ?

INTRODUCTION: Despite ongoing therapeutic advances in oncology, the use of the term cure in front of patients remains controversial. The word remission is often preferred in clinical practice. The purpose of this research is to explore how oncologists vary in their usage and definition of the word cure when talking to patients. METHODS: Qualitative and exploratory pilot study conducted by semi structured interviews with a group of French oncologists about a clinical vignette of localized breast cancer treated by surgery and complete adjuvant treatment. RESULTS: Thirteen oncologists participated in this study between January and March 2016. They were divided into two groups according to whether or not they use the term cure in their clinical practice. A first group of five doctors define the word cure as the lasting absence of relapse of the disease. Because of their duty of transparency and the uncertainty of post-therapeutic relapse, these five doctors tend to never use the word cure. The analysis of the second group of eight doctors, who do use of the word cure in their practice, highlighted an absence of consensus on its definition. However, all of them justify their use of it with the importance of expressing positive emotions such as hope to patients. DISCUSSION: Our findings confirm that there are divergent understandings of the concept of cure between oncologists and how they manage prognosis uncertainty. Medical language is thus influenced by scientific knowledge, but also by doctors' personal values and ways of thinking, perhaps influencing the doctor-patient relationship in turn. This exploratory study will be extended on a wider scale to explore the coexistence of other elements of diversity.