1,253 research outputs found
La biodiversité "aménage-t-elle" les territoires ? : vers une écologisation des territoires
Formé il y a moins de 30 ans, le mot « biodiversité » s’est rapidement diffusé et s’est récemment substitué aux termes plus usuels que sont la nature ou les espaces naturels. Ainsi que l’ont souligné Pascal Marty, Franck-Dominique Vivien, Jacques Lepart et Raphaël Larrère (2005), dans leur ouvrage « Les biodiversités : objets, théories, pratiques », le mot « biodiversité » dépasse désormais largement le champ de l’écologie auquel il fait référence et est mobilisé dans de nombreux débats, que ..
Developing Intensity-Duration-Frequency (IDF) Curves From Satellite-Based Precipitation: Methodology and Evaluation
Given the continuous advancement in the retrieval of precipitation from satellites, it is important to develop methods that incorporate satellite-based precipitation data sets in the design and planning of infrastructure. This is because in many regions around the world, in situ rainfall observations are sparse and have insufficient record length. A handful of studies examined the use of satellite-based precipitation to develop intensity-duration-frequency (IDF) curves; however, they have mostly focused on small spatial domains and relied on combining satellite-based with ground-based precipitation data sets. In this study, we explore this issue by providing a methodological framework with the potential to be applied in ungauged regions. This framework is based on accounting for the characteristics of satellite-based precipitation products, namely, adjustment of bias and transformation of areal to point rainfall. The latter method is based on previous studies on the reverse transformation (point to areal) commonly used to obtain catchment-scale IDF curves. The paper proceeds by applying this framework to develop IDF curves over the contiguous United States (CONUS); the data set used is Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks – Climate Data Record (PERSIANN-CDR). IDFs are then evaluated against National Oceanic and Atmospheric Administration (NOAA) Atlas 14 to provide a quantitative estimate of their accuracy. Results show that median errors are in the range of (17–22%), (6–12%), and (3–8%) for one-day, two-day and three-day IDFs, respectively, and return periods in the range (2–100) years. Furthermore, a considerable percentage of satellite-based IDFs lie within the confidence interval of NOAA Atlas 14
La solidarité écologique : un nouveau concept pour une gestion intégrée des parcs nationaux et des territoires
Cet article propose une première exploration du nouveau concept de solidarité écologique introduit dans le droit de l'environnement lors de la réforme de la loi sur les parcs nationaux français en 2006. Nous montrons que ce concept polysémique, tirant les enseignements de l'application de la loi de 1960, se fonde sur la prise de conscience des interdépendances du vivant et une nouvelle vision de la conservation de la nature. La solidarité écologique permet d'asseoir un compromis pragmatique entre écocentrisme et anthropocentrisme. Fondée sur les évolutions conceptuelles de l'écologie de la conservation, la solidarité écologique se décline selon une typologie qui intègre les enjeux de l'hétérogénéité spatiotemporelle de la biodiversité. Elle donne sens à l'élaboration des réseaux écologiques nationaux et internationaux et à la gestion intégrée des territoires de la biodiversité. La mise en débat public de ses spécificités locales et des valeurs qui lui sont attachées est nécessaire afin d'assurer sa considération et sa préservation
Supramolecular chemistry of helical foldamers at the solid-liquid interface: self-assembled monolayers and anion recognition
The synthesis of a redox-active helical foldamer and its immobilization onto a gold electrode are described. These large molecular architectures are grafted in a reproducible manner and provide foldamer-based self-assembled monolayers displaying recognition properties
Adenocarcinoma in Caroli's Disease Treated by Liver Transplantation
Caroli's disease is characterized by congenital cystic dilatation of the intrahepatic bile ducts. In 7% of
casea a malignant tumor develops complicating the course of the disease
Recurrent Primary Intrasellar Paraganglioma
We describe a case of an 81-year-old male presenting with bitemporal visual field defects and blurry vision in the right eye. The patient was found to have a recurrent primary paraganglioma in the sellar and suprasellar region requiring a repeat transsphenoidal endoscopic resection. Immunohistochemical examination confirmed paraganglioma with the classic zellballen appearance which stained positive for chromogranin, synaptophysin, and S-100 in the periphery. Paragangliomas (PGLs) in the sella turcica are a rare entity; only 19 cases have ever been reported in the literature. PGLs in the sellar region are often misdiagnosed or diagnosed in a delayed fashion. Earlier diagnosis of this locally aggressive tumor and meticulous debulking can prevent morbidity secondary to the tumor's compressive effects. This report highlights the effectiveness of surgical interventions in treatment of paragangliomas. More research is still needed to determine the need for adjuvant therapies such as radiation
Recommended from our members
Multimodal Brain Changes in First-Episode Mania: A Voxel-Based Morphometry, Functional Magnetic Resonance Imaging, and Connectivity Study
Background: Brain structural and functional changes in bipolar disorder (BD) are well-established findings, but it is uncertain whether these changes are already present in first episode mania (FEM).
Methods: We compared 31 FEM subjects, with 31 healthy individuals matched for age, sex, and premorbid IQ. Whole-brain voxel-wise morphometry, functional magnetic resonance imaging during the n-back task, and a functional connectivity analysis were performed.
Results: There were no volumetric differences between the 2 groups. During the 2-back task, FEM patients did not perform differently from controls and activated similar regions, but they showed less deactivation in the ventromedial prefrontal cortex (vmPFC), the anterior hub of the default mode network (DMN). They showed preserved functional connectivity between the vmPFC and other regions of the DMN, but increased connectivity with the superior frontal gyrus.
Conclusions: The absence of volumetric changes in FEM patients suggests that these changes could be related to progression of the illness. On the other hand, the failure of deactivation of the anterior hub of the DMN is present from the onset of the illness and may represent a core pathophysiological feature of BD
- …