Concept of Event by Heidegger, Vattimo and Badiou

This article analyses the different interpretation held of Heidegger, Vattimo and Badiou about the concept of «Event». For Heidegger and Vattimo, Event (Ereignis) is a form of self-giving of being that differs completely to the western metaphysical tradition’s form of thinking being-and time. This hermeneutical thought can be considered as an active nihilism. The concept of Event in Badiou is quite different. For the French Philosopher, there is some newness in being: it can be possible to think novelty. The philosophy of Badiou can then bring us news instruments to think novelty, radical changes and discontinuity in the historical process.Este artículo analiza las distintas interpretaciones del concepto de «acontecimiento » propuestas por Heidegger, Vattimo y Badiou. Para Heidegger y Vattimo, el acontecimiento es una forma de auto-donación del Ser que difiere radicalmente de la forma en que la tradición metafísica occidental ha pensado el Ser –y el tiempo. Este pensamiento hermenéutico puede ser caracterizado como una forma de nihilismo activo. El concepto de acontecimiento en Badiou es totalmente diferente. Para el filósofo francés, hay alguna novedad en el ser: es posible entonces, a partir de esta premisa, pensar la novedad. La filosofía de Badiou puede entonces proporcionarnos nuevos instrumentos para pensar la novedad, los cambios radicales y la discontinuidad en el proceso de la Histori

Characterization and regulation of the expression of scyllatoxin (Leiurotoxin I) receptors in the human neuroblastoma cell line NB-OK 1

Abstract125I-[Tyr2]scyllatoxin allowed to label a single class of high-affinity receptors in membranes from the human neuroblastoma cell line NB-OK 1. The Kd of these receptors was 60 pM for scyllatoxin (Leiurotoxin I) and 20 pM for apamin and the Bmax was low (3.8 fmol/mg membrane protein). K+ increased toxin binding at low concentrations but exerted opposite effects at high concentrations. Ca2+, guanidinium and Na+ exerted only inhibitory effects on binding. Scyllatoxin binding sites were overexpressed 2.5-fold after a 24-h cell pretreatment with 2 mM butyrate. This effect was suppressed by cycloheximide

Large-Eddy Simulations of Magnetohydrodynamic Turbulence in Heliophysics and Astrophysics

We live in an age in which high-performance computing is transforming the way we do science. Previously intractable problems are now becoming accessible by means of increasingly realistic numerical simulations. One of the most enduring and most challenging of these problems is turbulence. Yet, despite these advances, the extreme parameter regimes encountered in space physics and astrophysics (as in atmospheric and oceanic physics) still preclude direct numerical simulation. Numerical models must take a Large Eddy Simulation (LES) approach, explicitly computing only a fraction of the active dynamical scales. The success of such an approach hinges on how well the model can represent the subgrid-scales (SGS) that are not explicitly resolved. In addition to the parameter regime, heliophysical and astrophysical applications must also face an equally daunting challenge: magnetism. The presence of magnetic fields in a turbulent, electrically conducting fluid flow can dramatically alter the coupling between large and small scales, with potentially profound implications for LES/SGS modeling. In this review article, we summarize the state of the art in LES modeling of turbulent magnetohydrodynamic (MHD) ows. After discussing the nature of MHD turbulence and the small-scale processes that give rise to energy dissipation, plasma heating, and magnetic reconnection, we consider how these processes may best be captured within an LES/SGS framework. We then consider several special applications in heliophysics and astrophysics, assessing triumphs, challenges,and future directions

IMAGERIE OPTIQUE DANS LES MILIEUX FORTEMENT DIFFUSANTS PAR MODULATION ULTRASONORE DU SPECKLE (APPLICATION AUX TISSUS BIOLOGIQUES)

PARIS-BIUSJ-Physique recherche (751052113) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Standardization prospective in ESONET NoE and a possible implementation on the ANTARES Site

ESONET is a Multidisciplinary European Network of Excellence (NoE) associating 50 partners from 14 countries and more than 300 scientists and engineers and dedicated to the lasting integration of research and development in deep sea observatories in Europe. Amongst other actions, it works at establishing seafloor infrastructure that will provide platforms for instrumentation deployed throughout the water column and the geosphere below in a standard manner. Those platforms will provide power for instruments and real-time two-way data communications. This preparatory phase of observatory implementation is intended to select the most suitable standards in order to develop observatories that are interoperable between themselves and which would be able to benefit from the common sharing of facilities. After the ESONET Best Practices Workshop held in Bremen at the end of January 2008, the state of art has been set and some groups working on key standardization topics have been constituted to manage standardization plans. Some outputs are presented hereafter. Those plans will be implemented and tested in the recently-selected four so-called ESONET Demonstration Missions. The ANTARES Site as an ESONET regional node offers some facilities for the next call for demonstration missions. Scientific interest is briefly explained, with a specific focus on needs for oceanography. The technical possibility of new instrument implementation via a secondary junction box is then presented

Time-gated total internal reflection fluorescence microscopy with a supercontinuum excitation source

International audienceWe present the instrumental development of a versatile total internal reflection fluorescence lifetime imaging microscopy setup illuminated by a supercontinuum laser source. It enables performing wide- field fluorescence lifetime imaging with subwavelength axial resolution for a large range of fluorophores. The short overall acquisition time and the axial resolution are well suited for dynamic neurobiological applications

Homodimerization of Amyloid Precursor Protein at the Plasma Membrane: A homoFRET Study by Time-Resolved Fluorescence Anisotropy Imaging

Classical FRET (Förster Resonance Energy Transfer) using two fluorescent labels (one for the donor and another one for the acceptor) is not efficient for studying the homodimerization of a protein as only half of the homodimers formed can be identified by this technique. We thus resorted to homoFRET detected by time-resolved Fluorescence Anisotropy IMaging (tr-FAIM). To specifically image the plasma membrane of living cells, an original combination of tr-FAIM and Total Internal Reflection Fluorescence Lifetime Imaging Microscope (TIRFLIM) was implemented. The correcting factor accounting for the depolarization due to the high numerical aperture (NA) objective, mandatory for TIRF microscopy, was quantified on fluorescein solutions and on HEK293 cells expressing enhanced Green Fluorescence Protein (eGFP). Homodimerization of Amyloid Precursor Protein (APP), a key mechanism in the etiology of Alzheimer's disease, was measured on this original set-up. We showed, both in epifluorescence and under TIRF excitation, different energy transfer rates associated with the homodimerization of wild type APP-eGFP or of a mutated APP-eGFP, which forms constitutive dimers. This original set-up thus offers promising prospects for future studies of protein homodimerization in living cells in control and pathological conditions

Performance of a quick pregnancy test on whole blood in early pregnancy units a prospective cohort study

International audienceObjective - To assess the diagnostic performance of the NG-Test human chorionic gonadotropin (hCG) WB, which is a new point-of-care (POC) hCG whole-blood test. Materials and methods - This prospective study included women consulted in early pregnancy units for vaginal bleeding and/or pelvic pain with unknown pregnancy status after medical consultation including a pelvic ultrasound scan. A new POC test (the NG-Test hCG WB) and the usual laboratory serum test (considered the gold standard) were performed in patients. The results were interpreted in a blinded manner. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the NG-Test hCG WB. Results - During the study period, 200 patients were included. The pregnancy rate was 17%. For the laboratory test, with a 5 UI/l hCG positivity threshold, the sensitivity, specificity, PPV, NPV, and Youden index of the NG-Test hCG WB were 89.7, 100, 100, 97.9, and 0.90%, respectively. Considering a 10 UI/l hCG positivity threshold, test sensitivity, specificity, PPV, NPV, and Youden index were 96.3, 100, 100, 99.3, and 0.96%, respectively. False-negative cases were either extremely brief pregnancies or residual hCG after miscarriage. The result was obtained within 5 min with the NG-Test hCG WB versus 90±31 min with the laboratory test. It was easy to use. Conclusion - The NG-Test hCG WB showed a high sensitivity, specificity, PPV, and NPV. Its use as triage in the case of a negative pelvic ultrasound exam is a potential strategy to improve patient flow, with an average time saving of 85 min