2. Magnon spectra in layered samples: From NN exchange to dipolar coupling

International audienceThe dispersion relations of progressive spin waves and the stationary normal modes in thin films are derived according to a unified picture, by means of dynamical and transfer matrices. The full spectrum of stationary excitations and their localization properties are deduced. Numerical calculations confirm the increasing complexity of both dispersion relation and stationary mode localization when increasing interaction range. Recent experimental observations and micromagnetism simulations are confronted with these results. PACS numbers: 75.30.Ds; 72.15.R

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

Introduction to the Proceedings of the 8

This introduction to this pluridisciplinary meeting is mainly devoted to celebrate two exceptional pluridisciplinary scientists. Fernand Braudel was simultaneously a historian, geographer, sociologist and economist. The neurophysiologist Jean Delacour was open to other disciplines from philosophy to physics. Braudel’s global point of view of history created new fields in human sciences, paving the way for new active research. For instance, the emergence of the very singular development of world-cities remains to be well understood from detailed network analysis in order to find the driving process of such an emergent deep localization. In a similar way, Delacour’s physiological evidence for unconscious mind resulting from energy saving during sleep remains to be explored in details both for humans and for animals with expected consequences for managing neural networks as well as for quantum computing, and for poetry. The papers of this meeting are shortly introduced

Optical Diffraction of Stretched Lacunary Networks with Central Forces and Bond Bending Couplings

A numerically simulated network of randomly occupied sites connected by central forces and bond-bending couplings, whose the site concentration is slightly higher than the percolation threshold, is submitted to an external stretch. The optical diffraction pattern of the relaxed network is experimentally and analytically studied. In real space, regions at the boundary are shifted without being deformed, while most of the internal regions are rotated by some angles. Internal regions, bounded by pivots as usual in percolation theory are homogeneously rotated. These rotations are optically detected in reciprocal space and compared with the predictions of the theoretical model. Most of the stretching occurs by means of nearly free, independent rotations, without energy expense and thus with a very low bulk modulus.Après avoir simulé numériquement l'étirement d'un réseau aléatoire de sites reliés par des forces centrales entre sites occupés et par des forces proportionnelles aux écarts angulaires entre liaisons réalisées, la concentration en site étant proche de celle au seuil de percolation, on étudie analytiquement et expérimentalement la diffraction optique d'un tel réseau déformé. Aux bords du réseau, les atomes sont solidaires du déplacement imposé, tandis qu'à l'intérieur différentes rotations apparaissent et sont détectées par diffraction. Ces régions internes, indépendantes, sont limitées par des pivots dont l'observation est usuelle dans les phénomènes de percolation. Les mesures dans l'espace direct, comme l'espace réciproque, de l'amplitude de ces rotations correspondent aux déductions théoriques qu'on peut mener à partir du modèle. L'étirement global résulte de la coordination de multiples rotations locales et donc la rigidité effective du milieu est très faible

Optical diffraction of fractal figures: random Sierpinski carpets

The optical diffraction patterns of random Sierpinski carpets of different fractal dimensions at different levels of iteration are shown and analyzed. The sensitivity of such an analysis to long range correlations, is demonstrated theoretically by means of the transfer matrix formalism of fractals, T.M.F. The relation between the subdimensions defined in T.M.F. and diffraction patterns is outlined. Finally an analysis of experimental diffraction patterns is proposed in order to measure these new theoretical subdimensions.On présente ici les clichés de diffraction optique de tapis de Sierpinski aléatoires de différentes dimensions fractales, pris à des niveaux d'itération différents. Au moyen du formalisme de la matrice de transfert dans les fractals, on montre la sensibilité de cette analyse expérimentale aux corrélations à moyenne et longue portée. Ainsi la relation entre les sous-dimensions fractales du F.M.T. et les rapports d'intensité entre les clichés de diffraction de figures fractales à des niveaux d'itération différents est soulignée. Enfin on esquisse le principe d'une analyse expérimentale de ces nouvelles dimensions théoriques

Sedentary behavior, physical inactivity and body composition in relation to idiopathic infertility among men and women

International audienceBackground Physical activity (PA) and sedentary behavior have inconsistent effects on fertility. High body mass index is associated with infertility but to our knowledge, very few studies have explored body composition in association to fertility. Objective To assess the association between physical inactivity, sedentary behavior, body composition and idiopathic infertility in French men and women. Design We conducted a case-control multicentric observational study. 159 infertile (79 men and 80 women) and 143 fertile (72 men and 71 women) were recorded in four fertility centers. Main outcome measures Participants completed self-administered questionnaires on sociodemographic and lifestyle characteristics, dietary intake, physical activity and sedentary behavior. Anthropometrics were measured, and bioelectrical impedance analysis was used to estimate body composition. Multivariable logistic regression was used to analyze the association of fertility with PA level and sedentary behavior. Results In men, being physically inactive (Odd ratio [OR] 2.20; 95% confidence interval [CI], 1.06, 4.58) and having fat mass greater than the reference values for their age (OR 2.83; 95% CI, 1.31, 6.10) were positively associated with infertility. Sedentary behavior and fat-free mass were not related to infertility in men. In women, sedentary behavior (OR 3.61; 95% CI, 1.58, 8.24), high body fat (OR 3.16; 95% CI, 1.36, 7.37) and low fat-free mass (OR 2.65; 95% CI, 1.10, 6.37) were associated with infertility. PA level was not associated with fertility in women. Conclusions This study suggests that sedentary behavior and physical inactivity would represent two independent risk factors associated with infertility. The various elements that make up physical activity (frequency, intensity, time, and type of exercise) and the interrupting time spent sitting should be considered. Body composition variation should be explored further in relation to the biological pathways involved in idiopathic infertility. Moreover, the improvement of lifestyle factors should be considered in infertility treatment