Impact of metabolic perturbation on ovarian function

Metabolic perturbations including hyperinsulinemia that are induced during obesity and heat stress in humans and production animals are allied with several health hallmarks and impaired fertility. This dissertation research focused on charactering the impact of changes to central metabolism on ovarian function. We hypothesized that hyperinsulinemia induced during central metabolic perturbations, alters ovarian insulin-mediated PI3K signaling, negatively impacting ovarian folliculogenesis, steroidogenesis and xenobiotic biotransformation. To test this hypothesis, mRNA and protein expression profiles of insulin, PI3K, steroidogenic, inflammatory and chemical metabolism members were quantified using qRT-PCR, Western blotting or immunohistochemistry techniques using three models of hyperinsulinemia: 1) high fat diet (HFD)-induced obesity, 2) a transgenic mouse model of progressive obesity and 3) a porcine model of hyperinsulinemia. Overall, our data demonstrates that the ovarian insulin-KITLG-KIT-AKT signaling pathway is active and upregulated during central metabolic alterations. Perturbations to ovarian insulin-KITLG-KIT-AKT signaling pathway are likely to impact 1) follicle activation, oocyte viability and recruitment, 2) steroid hormone biosynthesis, and 3) xenobiotic biotransformation, potentially accelerating susceptibility to chemical exposure. All of these scenarios could lead to impairment of ovarian function, and may at least partially explain why female fecundity is compromised during altered metabolic states

A new filtering approach dedicated to heat sources computation from thermal field measurements

International audienceThis paper presents a new approach in heat source evaluation from thermal field measurements. A modal projection based on dynamics (Discrete Modal Decomposition) is used to estimate the spatial term of a heat diffusion problem. A numerical example is presented in order to validate this approach and compare it to a more classical spectral decompostion (based on strictly thermal considerations). Results show that the proposed projection basis not only provides closer assessement of the heat sources but is also more stable to measurement noise and side effects

Quasi One-Dimensional Photonic Crystals as Building Block for Compact Integrated Optical Refractometric Sensors

A quasi one-dimensional photonic crystal has been fabricated and the applicability of this strong grating for optical sensing has been investigated by measuring the transmission spectra as a function of the cladding refractive index. The cladding index was varied a small range. By monitoring the transmitted output power the transmission stop-band was found to shift by 1 nm wavelength for either a cladding refractive index change of 0.05 or a temperature change of 120 K

Quasi 1-dimensional photonic crystals as building block for compact integrated optical sensors

A quasi one-dimensional photonic crystal has been fabricated and the applicability of this kind of structure for optical sensing has been investigated by measuring the transmission spectra as a function of the cladding refractive index. The cladding index was varied using a liquid flow, of which the index was slowly varied over a small range. The shift with cladding index of the steep stop band edge provides a relatively sensitive detection mechanism in an extremely compact device

Sensibilité des observables radars à la variabilité temporelle et à la configuration géométrique de forêts tempérées et tropicales à partir de mesure de proximité haute-résolution

L'augmentation importante de la population mondiale, et par conséquent de ses besoins, exerce une pression de plus en plus importante sur les surfaces forestières. L'outil le mieux adapté au suivi des forêts, à l'échelle du globe, est la télédétection. C'est dans ce contexte que se situe ce travail de thèse, qui vise à améliorer l'estimation des paramètres biophysiques des arbres à partir de données de télédétection. L'originalité de ce travail a été d'étudier cette estimation des paramètres biophysiques en menant plusieurs études de sensibilité avec une démarche expérimentale sur des données expérimentales et sur des données simulées. Tout d'abord, l'étude s'est portée sur des séries temporelles de mesures de diffusiométrie radar obtenues sur deux sites : l'un constitué d'un cèdre en zone tempérée et l'autre d'une parcelle de forêt tropicale. Puis, cette étude de sensibilité a été poursuivie en imageant, avec une résolution élevée, plusieurs parcelles aux configurations différentes à l'intérieur d'une forêt de pin. Enfin, des données optiques et radars simulées ont été fusionnés afin d'évaluer l'apport de la fusion de données optique et radar dans l'inversion des paramètres biophysiques.The significant increase of the world population, and therefore its needs, pushes increasingly high in forest areas. The best tool for monitoring forest across the globe is remote sensing. It is in this context that this thesis, which aims to improve the retrieval of biophysical parameters of trees from remote sensing data, takes place. The originality of this work was to study the estimation of biophysical parameters across multiple sensitivity studies on experimental data and simulated data. First, the study focused on the time series of radar scatterometry measurements obtained on two sites: one characterized by a cedar in the temperate zone and the other by a forest plot of rainforest. Then, the sensitivity analysis was continued by imaging with high resolution, several forest plots with different configurations within a pine forest. Finally, simulated radar and optical data were combined to evaluate the contribution of optical and radar data fusion in the inversion of biophysical parameters.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

Modelling the distribution of the Ocellated Lizard in France : implications for conservation

The Ocellated Lizard, Timon lepidus (Daudin 1802) occupies the Mediterranean regions of southwestern Europe (Portugal, Spain, France, and the extreme northwest of Italy). Over the last decades, a marked decline in its population has been observed, particularly on the northern edge of its distribution. As a result, it is currently considered a threatened species, especially in France and Italy. In France, a national action plan for its conservation has been put in place. In this study, ecological niche modelling (ENM) was carried out over the entire area of France in order to evaluate the species' potential distribution, more accurately define its ecological niche, guide future surveys, and inform land use planning so this species can be better taken into consideration. The modelling used data representing 2,757 observation points spread over the known range of the species, and 34 ecogeographical variables (climate, topography, and vegetation cover) were evaluated. After removing correlated variables, models were fitted with several combinations of variables using eight species distribution model (SDM) algorithms, and then their performance was assessed using three model accuracy metrics. Iterative trials changing the input variables were used to obtain the best model. The optimized model included nine determining variables. The results indicate the presence of this species is linked primarily to three climate variables: precipitation in the driest month, precipitation seasonality, and mean temperature in the driest quarter. The model was checked by a sample dataset that was not used to fit the model, and this validation dataset represented 25% of the overall field observations. Of the known occurrence locations kept aside to check the results, 94% fell within the presence area predicted by the modelled map with a presence probability greater than 0.7, and 90% fell within the area with a presence probability ranging from 0.8 to 1, which represents a very high predictive value. These results indicate that the models closely matched the observed distribution, suggesting a low impact of either geographical factors (barriers to dispersal), historical factors (dispersal process), or ecological factors (e.g., competition, trophic resources). The overlap between the predicted distribution and protected areas for this species reveals that less than 1% of the potential distribution area is protected by strong regulatory measures (e.g., national parks and natural reserves). The knowledge obtained in this study allows us to recommend some guidelines that would favor the conservation of this species.Peer reviewe

Coastal protection assessment: a tradeoff between ecological, social, and economic issues

Marine coastal ecosystems are crucial to human populations in reducing disaster risk. Least Developed Countries are particularly vulnerable to the effects of climate change, such as sea-level rise and storm surges. The Mauritanian coast, West Africa, ranks among the most vulnerable worldwide to sea-level rise, and coastal communities in the National Park of Banc d’Arguin (PNBA) are particularly at risk. Here, we assessed the service of coastal protection in PNBA by (1) mapping the coastal marine ecosystems with Sentinel-2 imagery and determining their spatial wave height attenuation rates; (2) assessing the vulnerability of villages and natural habitats to coastal hazard risk; and (3) assessing the applicability of coastal protection measures in the PNBA. We found that a total of 83% of the populated coastline presents a moderate to high risk of flooding and erosion, with Iwik and R’Gueiba being the most threatened villages in the PNBA. As for the ecological risk, two low-elevated islands, which support breeding colonies of birds, are particularly vulnerable to sea-level rise. However, in other areas, the rupture in the dune cord created new lagoons that present valuable ecological and economic interests like the Lagoon of Bellaat. Improving the comprehension of wave attenuation provided by coastal habitats, combined with identifying the vulnerability and applicability of coastal protection measures, is essential for achieving the Sendai Framework for Disaster Risk Reduction goals. In the PNBA, relocation of identified villages at risk is probably the best cost-effective solution with the least disturbance to both breeding and wintering birds. Protection of coastal ecosystems will also ensure a continued provision of other ecosystem services, including food supply for sea dependent populations, and contribute to achieving the Paris Agreement and Sustainable Development Goals

Time-reversal symmetry relation for nonequilibrium flows ruled by the fluctuating Boltzmann equation

A time-reversal symmetry relation is established for out-of-equilibrium dilute or rarefied gases described by the fluctuating Boltzmann equation. The relation is obtained from the associated coarse-grained master equation ruling the random numbers of particles in cells of given position and velocity in the single-particle phase space. The symmetry relation concerns the fluctuating particle and energy currents of the gas flowing between reservoirs or thermalizing surfaces at given particle densities or temperatures.Comment: The result of this paper has been presented at the conference "Boltzmann equation: mathematics, modeling and simulations" in memory of Carlo Cercignani at the Henri Poincar\'e Institute, Paris, February 9-11, 201

Les référents du littéraire

Le processus de création littéraire, qu'essaie d'appréhender l'étude de l'arrière-texte, met en jeu un triple rapport : au monde extérieur, théâtre de nos vies individuelles et collectives, au monde intérieur des pensées conscientes ou inconscientes, aux œuvres littéraires ou artistiques qui font jouer ensemble ces deux mondes. Dès lors se repose la question du ou plutôt des référents, cette catégorie hétérogène étant envisagée ici sur un mode pluriel. L’espace – géographique, psychique, sémiotique – pourrait être la notion aidant à concevoir l’articulation de cette pluralité à l’œuvre dans la relation littéraire

Use of Vandenberg and Kuse Mental Rotation Test to Predict Practical Performance of Sinus Endoscopy

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