Démarche d'estimation des incertitudes en PIV basée sur la méthode GUM

International audienceLe travail présenté ici propose une procédure d’estimation des incertitudes pour des mesures type PIV basée sur la méthode GUM (Guide to the expression of Uncertainly in Measurement). La démarche proposée par le GUM normalise la façon de propager les incertitudes lorsque l’on dispose d’un modèle mathématique reliant la grandeur mesurée aux variables permettant sa détermination et qui représentent les sources d’incertitudes. Pour la détermination des incertitudes, relativement peu d’articles traitent du processus de mesure et suivent une procédure établie. La source d’erreur la plus étudiée, est celle provenant des algorithmes. Dans cette étude, une procédure détaillée d’estimation des incertitudes est présentée. Cette procédure est appliquée à des deux configurations de mesure 2D afin d’obtenir des cartes d’incertitude sur les champs de vitesse instantanés

Experimental study of the dominant modes and its contributions to the detached internal flows in a TIC nozzle

During the transient phases of start-up and shut-down, liquid engine nozzles operate under severe over-expanded conditions. Furthermore, these transient phases result in rocket nozzles exhibiting dynamic off-axis loads caused by asymmetric internal separation. There are two recognisable types of flow separation, Free-Shock Separation, FSS, and Restricted-Shock Separation, RSS. It has been shown that the resultant separation type depends largely on nozzle geometry. Many studies have analysed these distinct separation patterns concluding that FSS topologies result in lower magnitude side forces than RSS ones. Moreover, it has been shown that Truncated Ideal Contour, TIC, nozzles only experience FSS separation. Thus, this work presents an experimental study of a TIC nozzle developed in a cold supersonic wind tunnel at PPrime Institute in Poitiers. The study consists of a series of pressure measurements as well as PIV and Schlieren Photography for a range of pre-selected pressure ratios which permit the characterisation of the regime where the nozzle undergoes the most significant jet fluctuations as it is believed that they are strongly associated with the side-loads

CheckMate-032 study: efficacy and safety of nivolumab and nivolumab plus ipilimumab in patients with metastatic esophagogastric cancer

Purpose: Metastatic esophagogastric cancer treatments after failure of second-line chemotherapy are limited. Nivolumab demonstrated superior overall survival (OS) versus placebo in Asian patients with advanced gastric or gastroesophageal junction cancers. We assessed the safety and efficacy of nivolumab and nivolumab plus ipilimumab in Western patients with chemotherapy-refractory esophagogastric cancers. Patients and Methods: Patients with locally advanced or metastatic chemotherapy–refractory gastric, esophageal, or gastroesophageal junction cancer from centers in the United States and Europe received nivolumab or nivolumab plus ipilimumab. The primary end point was objective response rate. The association of tumor programmed death-ligand 1 status with response and survival was also evaluated. Results: Of 160 treated patients (59 with nivolumab 3 mg/kg, 49 with nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, 52 with nivolumab 3 mg/kg plus ipilimumab 1 mg/kg), 79% had received two or more prior therapies. At the data cutoff, investigator-assessed objective response rates were 12% (95% CI, 5% to 23%), 24% (95% CI, 13% to 39%), and 8% (95% CI, 2% to 19%) in the three groups, respectively. Responses were observed regardless of tumor programmed death-ligand 1 status. With a median follow-up of 28, 24, and 22 months across the three groups, 12-month progression-free survival rates were 8%, 17%, and 10%, respectively; 12-month OS rates were 39%, 35%, and 24%, respectively. Treatment-related grade 3/4 adverse events were reported in 17%, 47%, and 27% of patients in the three groups, respectively. Conclusion: Nivolumab and nivolumab plus ipilimumab demonstrated clinically meaningful antitumor activity, durable responses, encouraging long-term OS, and a manageable safety profile in patients with chemotherapy-refractory esophagogastric cancer. Phase III studies evaluating nivolumab or nivolumab plus ipilimumab in earlier lines of therapy for esophagogastric cancers are underway

Nivolumab Monotherapy and Nivolumab Plus Ipilimumab in Recurrent Small Cell Lung Cancer: Results From the CheckMate 032 Randomized Cohort

Abstract Introduction Nivolumab monotherapy is approved in the United States for third-line or later metastatic small cell lung cancer based on pooled data from nonrandomized and randomized cohorts of the multicenter, open-label, phase 1/2 trial of nivolumab ± ipilimumab (CheckMate 032; NCT01928394). We report updated results, including long-term overall survival (OS), from the randomized cohort. Methods Patients with small cell lung cancer and disease progression after one to two prior chemotherapy regimens were randomized 3:2 to nivolumab 3 mg/kg every 2 weeks or nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks for four cycles followed by nivolumab 3 mg/kg every 2 weeks. Patients were stratified by number of prior chemotherapy regimens and treated until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by blinded independent central review. Results Overall, 147 patients received nivolumab and 96 nivolumab plus ipilimumab. Minimum follow-up for ORR/progression-free survival/safety was 11.9 months (nivolumab) and 11.2 months (nivolumab plus ipilimumab). ORR increased with nivolumab plus ipilimumab (21.9% versus 11.6% with nivolumab; odds ratio: 2.12; 95% confidence interval: 1.06–4.26; p = 0.03). For long-term OS, minimum follow-up was 29.0 months (nivolumab) versus 28.4 months (nivolumab plus ipilimumab); median (95% confidence interval) OS was 5.7 (3.8–7.6) versus 4.7 months (3.1–8.3). Twenty-four–month OS rates were 17.9% (nivolumab) and 16.9% (nivolumab plus ipilimumab). Grade 3 to 4 treatment-related adverse event rates were 12.9% (nivolumab) versus 37.5% (nivolumab plus ipilimumab), and treatment-related deaths were n =1 versus n = 3, respectively. Conclusions Whereas ORR (primary endpoint) was higher with nivolumab plus ipilimumab versus nivolumab, OS was similar between groups. In each group, OS remained encouraging with long-term follow-up. Toxicities were more common with combination therapy versus nivolumab monotherapy

RÔLE DE L'OCCUPATION DU SOL VIS À VIS DE LA MODÉLISATION DES FLUX ENERGÉTIQUES ET HYDRIQUES EN MILIEU URBAIN ET PÉRIURBAIN

National audienceLe projet Rosenhy vise à étudier l’impact de l’occupation du sol sur la modélisation météorologique et hydrologique en termes de flux énergétiques et hydriques, en milieu urbain et périurbain. Trois sites appartenant aux observatoires français OTHU et ONEVU sont au centre de ce projet. Le quartier urbain hétérogène du Pin sec (Nantes), imperméabilisé à environ 45%, a fait l’objet d’une campagne expérimentale durant le mois de juin 2012, visant à estimer les flux de chaleur sensible et latente avec une haute résolution spatiale et temporelle par rapport aux mesures réalisées en continu sur ce site depuis 5 ans. Deux bassins versant périurbains (La Chézine à Nantes et l’Yzeron à Lyon), avec un taux d’imperméabilisation moins important (environ 10%) mais grandissant depuis plusieurs décennies, sont aussi étudiés. Ces deux derniers sites bénéficient d’un suivi hydrométéorologique depuis 10 ans pour la Chézine et 15 ans pour l’Yzeron. Sur ces trois sites, différentes sources de données d’occupation du sol à différentes résolutions sont disponibles :différentes bases de données géographiques communément utilisées par la communauté scientifique et les collectivités et des données télédétectées (multispectrales et hyperspectrales). L’utilisation de ces données en entrée de différents modèles météorologiques et hydrologiques implique un travail d’analyse et de classification pour adapter les informations aux besoins des modèles. Dans ce projet, les différents modèles adaptés au milieu urbain ou périrubain sont évalués et améliorés. Ainsi, les modèles hydrologiques périrubains sont en développement pour prendre en compte les différentes pratiques de gestion des eaux pluviales existantes (noues, toitures végétalisées, ...). L’utilisation conjointe des données simulées par les différents modèles aidera à déterminer le rôle de la part des surfaces naturelles et artificielles sur les bilans énergétique et hydrique en milieu plus ou moins urbanisé. Le milieu périurbain étant en évolution, le projet s’intéressera aussi à des scénarios d’urbanisation prospectifs en regardant d’une part l’impact de la densification sur les scénarios construits pour l’Yzeron lors du projet AVuPUR (ANR-VMCS, 2008-2011) et d’autre part, en réfléchissant conjointement avec Nantes Métropole, aux possibles voies d’évolution sur le bassin de la Chézine

Coupled measurements of interface topography and three-dimensional velocity field of a free surface flow

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Time-resolved scanning tomography PIV measurements around a flapping wing

International audienceThe three-dimensional flow that develops around a finite flapping wing is investigated using a tomographic scanning PIV technique. The acquisition and correlation processes employed to achieve such measure- ments have been carefully validated. Issues regarding the relevant timescales of the flow and the spanwise space- resolution are addressed. Results obtained on a hovering flapping wing whose plunging phase is described by a rectilinear motion highlight the influence of the free end condition and the formation of the tip vortex on the leading edge vortices behavior, wing/wake interactions, and wake stabilization

Étude expérimentale des champs turbulents acoustiques à l'immédiat aval d'une onde de choc

National audienceAn original measurement technique based on Rayleigh scattering (Collective Light Scattering) was used in the flow conditions of a normal Mach 2.85 shock wave/homogeneous turbulence interaction. The experimental investigation was limited to the region just downstream of the shock. A non-dimensional attenuation law for the evanescent acoustic waves was found using CLS measurements. This law is significantly different from the one predicted by the Linear Interaction Analysis. However, it was confirmed by hot-wire measurements for which quite severe assumptions were used.Une nouvelle méthode de mesure basée sur la diffusion Rayleigh (Diffusion Collective de la Lumière) a été mise en œuvre et testée dans une configuration d'intéraction onde de choc droite/turbulence homogène isotrope à Mach 2,85. L'investigation expérimentale s'est concentrée sur la région immédiatement en aval du choc. Les mesures DCL ont permis de déterminer une loi adimensionnelle d'évanescence des ondes acoustiques émise à l'aval du choc. Cette loi, différente de celle issue de la théorie, est toutefois confirmée par l'exploitation de mesures fil chaud mettant en œuvre des hypothèses assez sévères

Individual differences in adapting to temperature in French students are only related to attachment avoidance and loneliness

Among animals, natural selection has resulted in a broad array of behavioural strategies to maintain core body temperature in a relatively narrow range. One important temperature regulation strategy is social thermoregulation , which is often done by warming the body together with conspecifics. The literature suggests that the same selection pressures that apply to other animals also apply to humans, producing individual differences in the tendency to socially thermoregulate. We wanted to investigate whether differences in social thermoregulation desires extend to other personality factors in a sample of French students. We conducted an exploratory, hypothesis-generating cross-sectional project to examine associations between thermoregulation and personality. We used conditional random forests in a training segment of our dataset to identify clusters of variables most likely to be shaped by individual differences to thermoregulate. We used the resulting clusters to fit hypothesis-generating mediation models. After we replicated the relationships in two datasets, personality was not related to social thermoregulation desires, with the exception of attachment avoidance. Attachment avoidance in turn predicted loneliness. This mediation proved robust across all three datasets. As our cross-sectional studies allow limited causal inferences, we suggest investing into prospective studies to understand whether and how social thermoregulation shapes attachment avoidance early in life and loneliness later in life. We also recommend replication of the current relationships in other climates, countries, and age groups