Orthonormal Systems in Linear Spans

We show that any $N$-dimensional linear subspace of $L^2(\mathbb{T})$ admits an orthonormal system such that the $L^2$ norm of the square variation operator $V^2$ is as small as possible. When applied to the span of the trigonometric system, we obtain an orthonormal system of trigonometric polynomials with a $V^2$ operator that is considerably smaller than the associated operator for the trigonometric system itself.Comment: 18 page

THEME SERIES - UPR in Cancer

International audienceOver the past decade endoplasmic reticulum (ER) stress signaling pathways have collectively emerged as an essential mechanism at the crossroads of the cellular functions involved in key steps of cancer development. ER stress signaling has pleiotropic roles in cancer, and is involved at the level of cell transformation, tumor growth and metastasis as well as resistance to chemo- and radio-therapy. Indeed beyond the instrumental roles of the ER in the biogenesis of secretory and transmembrane proteins..

Grain Prices and Mortality - A Note on La Michodières Law

Research linking food prices and excess mortality has a long history in applied economics and economic history. It goes back to 1766, when Jean-Baptiste de la Michodière was the first to use empirical data to argue for a positive association between wheat prices and mortality. Here La Michodière's time series are subjected to closer statistical scrutiny: the correlation survives, though it is less strong than some later scholars asserted. We also test for the price-mortality link using cross- section data for the 1690s and 1700s.food prices, famine, economic history, history of economic thought

Prix, goût ou diététique : expliquer les permanences et les modifications des approvisionnements alimentaires des Dames de Saint-Cyr au 18e siècle

Les achats alimentaires des Dames de Saint-Cyr s'offrent comme une expérience de laboratoire pour l'analyse des pratiques et des normes de consommation qui nous renvoie à nos préoccupations actuelles concernant les possibilités d'infléchir des régimes alimentaires par les prix et la diffusion d'information. Les prix des denrées n'expliquent pas les approvisionnements de l'institution saint-cyrienne, contrainte par son statut aristocratique à maintenir certaines consommations mais apparemment renseignée sur l'évolution des recommandations diététiques qui rendent compte de la modification séculaire de son régime alimentaire. Ainsi le raisonnement historique produit des connaissances substantielles sur les déterminants des achats alimentaires et offre la possibilité de tester la pertinence des méthodologies couramment mises en oeuvre pour expliquer (et agir sur) le monde contemporain.

Endoplasmic Reticulum Stress-Activated Cell Reprogramming in Oncogenesis

International audienceUnlabelled - Stress induced by the accumulation of unfolded proteins in the endoplasmic reticulum (ER) is observed in many human diseases, including cancers. Cellular adaptation to ER stress is mediated by the unfolded protein response (UPR), which aims at restoring ER homeostasis. The UPR has emerged as a major pathway in remodeling cancer gene expression, thereby either preventing cell transformation or providing an advantage to transformed cells. UPR sensors are highly regulated by the formation of dynamic protein scaffolds, leading to integrated reprogramming of the cells. Herein, we describe the regulatory mechanisms underlying UPR signaling upon cell intrinsic or extrinsic challenges, and how they engage cell transformation programs and/or provide advantages to cancer cells, leading to enhanced aggressiveness or chemoresistance. We discuss the emerging cross-talk between the UPR and related metabolic processes to ensure maintenance of protein homeostasis and its impact on cell transformation and tumor growth. Significance - ER stress signaling is dysregulated in many forms of cancer and contributes to tumor growth as a survival factor, in addition to modulating other disease-associated processes, including cell migration, cell transformation, and angiogenesis. Evidence for targeting the ER stress signaling pathway as an anticancer strategy is compelling, and novel agents that selectively inhibit the UPR have demonstrated preliminary evidence of preclinical efficacy with an acceptable safety profile

How to measure the relevance of a retargeting approach?

International audienceMost cell phones today can receive and display video content. Nonetheless, we are still significantly behind the point where premium made for mobile content is mainstream, largely available, and affordable. Significant issues must be overcome. The small screen size is one of them. Indeed, the direct transfer of conventional contents (not specifically shot for mobile devices) will provide a video in which the main characters or objects of interest may become indistinguishable from the rest of the scene. Therefore, it is required to retarget the content. Different solutions exist, either based on distortion of the image, on removal of redundant areas, or cropping. The most efficient ones are based on dynamic adaptation of the cropping window. They significantly improve the viewing experience by zooming in the regions of interest. Currently, there is no common agreement on how to compare different solutions. A retargeting metric is proposed in order to gauge its quality. Eye-tracking experiments, zooming effect through coverage ratio and temporal consistency are introduced and discussed