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Search Results: 1 - 10 of 26941 matches for " Jean-Philippe Girard "
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Sobolev Spaces, Schwartz Spaces, and a Definition of the Electromagnetic and Gravitational Coupling  [PDF]
Jean-Philippe Montillet
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.810100
Abstract: The concept of multiplicity of solutions was developed in [1] which is based on the theory of energy operators in the Schwartz space S-(R) and some subspaces called energy spaces first defined in [2] and [3]. The main idea is to look for solutions of a given linear PDE in those subspaces. Here, this work extends previous developments in S-(Rm)?(m∈Z+) using the theory of Sobolev spaces. Furthermore, we also define the concept of Energy Parallax, which is the inclusion of additional solutions when varying the energy of a predefined system locally by taking into account additional smaller quantities. We show that it is equivalent to take into account solutions in other energy subspaces. To illustrate the theory, one of our examples is based on the variation of Electro Magnetic (EM) energy density within the skin depth of a conductive material, leading to take into account derivatives of EM evanescent waves, particular solutions of the wave equation. The last example is the derivation of the Woodward effect [4] with the variations of the EM energy density under strict assumptions in general relativity. It finally leads to a theoretical definition of an electromagnetic and gravitational (EMG) coupling.
Discussion on the Energy Parallax and the Relationship to Perturbation Theory in Mathematical Physics  [PDF]
Jean-Philippe Montillet
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.93034
Abstract: This work is a discussion on the energy parallax theory developed in [1] [2] based on the multiplicity of the solutions theorem. This theory is compared with the perturbation theory in mathematical physics. The perturbation theory uses the increment of a solution which can be formalized with a Taylor series development. With the energy parallax theory, the convergence property of the Taylor series of the energy of a system is the key to decide to include additional solutions, defined on the so-called energy spaces [2]. The development is supported using various examples in quantum mechanics (i.e. Rayleigh-Schrödinger perturbation theory) and wave theory with the Electromagnetic (EM) energy density (i.e. evanescent waves within the skin layer of a dielectric material). Finally, we discuss the Woodward effect [3] and the application of the energy parallax when assuming that the variations of EM energy density can trigger such effect within asymmetric cavities.
The IL-1-Like Cytokine IL-33 Is Constitutively Expressed in the Nucleus of Endothelial Cells and Epithelial Cells In Vivo: A Novel ‘Alarmin’?
Christine Moussion, Nathalie Ortega, Jean-Philippe Girard
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003331
Abstract: Background Interleukin-33 (IL-33) is an IL-1-like cytokine ligand for the IL-1 receptor-related protein ST2, that activates mast cells and Th2 lymphocytes, and induces production of Th2-associated cytokines in vivo. We initially discovered IL-33 as a nuclear factor (NF-HEV) abundantly expressed in high endothelial venules from lymphoid organs, that associates with chromatin and exhibits transcriptional regulatory properties. This suggested that, similarly to IL-1α and chromatin-associated cytokine HMGB1, IL-33 may act as both a cytokine and a nuclear factor. Although the activity of recombinant IL-33 has been well characterized, little is known yet about the expression pattern of endogenous IL-33 in vivo. Methodology/Principal Findings Here, we show that IL-33 is constitutively and abundantly expressed in normal human tissues. Using a combination of human tissue microarrays and IL-33 monoclonal and polyclonal antibodies, we found that IL-33 is a novel nuclear marker of the endothelium widely expressed along the vascular tree. We observed abundant nuclear expression of IL-33 in endothelial cells from both large and small blood vessels in most normal human tissues, as well as in human tumors. In addition to endothelium, we also found constitutive nuclear expression of IL-33 in fibroblastic reticular cells of lymphoid tissues, and epithelial cells of tissues exposed to the environment, including skin keratinocytes and epithelial cells of the stomach, tonsillar crypts and salivary glands. Conclusions/Significance Together, our results indicate that, unlike inducible cytokines, IL-33 is constitutively expressed in normal human tissues. In addition, they reveal that endothelial cells and epithelial cells constitute major sources of IL-33 in vivo. Based on these findings, we speculate that IL-33 may function, similarly to the prototype ‘alarmin’ HMGB1, as an endogenous ‘danger’ signal to alert the immune system after endothelial or epithelial cell damage during trauma or infection.
Endothelial cell phenotypes in the rheumatoid synovium: activated, angiogenic, apoptotic and leaky
Jim Middleton, Laure Americh, Regis Gayon, Denis Julien, Luc Aguilar, Francois Amalric, Jean-Philippe Girard
Arthritis Research & Therapy , 2004, DOI: 10.1186/ar1156
Abstract: Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disease affecting the joints, and is associated with increased morbidity and mortality [1-3]. The synovium or synovial membrane, which surrounds the joint cavity, becomes massively hypertrophied in RA. This tissue, known as pannus, can become invasive, penetrating and degrading the cartilage and bone, resulting in joint deformities, in functional deterioration and in profound disability.The lining layer, or intima, of the synovium is normally one to three cells thick and it comprises macrophage-like cells and fibroblast-like cells [4]. This layer undergoes thickening and hypertrophy in RA, largely due to the increased recruitment of monocytes from the blood supply in the deeper layer, or subintima, of the tissue [5,6]. Other inflammatory cells such as T cells (mainly CD45RO) and B lymphocytes migrate from the blood into the synovium and can form ectopic lymphoid follicles around blood vessels. These structures resemble the lymphoid follicles of lymph nodes. In addition, neutrophils migrate into the synovium and end up in large numbers in the synovial joint fluid.Endothelial cells are active participants in the inflammatory process. They are involved in diverse activities including the regulation of leukocyte extravasation, angiogenesis, cytokine production, protease and extracellular matrix synthesis, vasodilation and blood vessel permeability, and antigen presentation [7].In RA, endothelial cells in the synovium are generally held to play a central role in the pathophysiology. The cells achieve this in several ways. First, as a component of blood vessels in the subintima, endothelial cells allow the migration of leukocytes such as T cells, B cells, monocytes, neutrophils and dendritic cells into the joint tissues and fluid. Endothelial cells undergo activation, expressing adhesion molecules and presenting chemokines, leading to leukocyte migration from the blood into the tissue. Second, the permeability
Counting Types of Runs in Classes of Arborescent Words  [PDF]
Jean-Philippe Labbé, Gilbert Labelle
Open Journal of Discrete Mathematics (OJDM) , 2013, DOI: 10.4236/ojdm.2013.31002
Abstract: An arborescence is a directed rooted tree in which all edges point away from the root. An arborescent word is obtained by replacing each element of the underlying set of an arborescence by an arbitrary letter of a given alphabet (with possible repetitions). We define a run in an arborescent word as a maximal sub-arborescent word whose letters are all identical. Various types of runs (e.g., runs of sizek, linear runs, etc) are studied in the context of R-enriched arborescent words, where R is a given species of structures.
Transmission of N-Atoms Produced by N2 Flowing Microwave Afterglows through Hollow Tubes  [PDF]
Andre Ricard, Jean-Philippe Sarrette
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2013, DOI: 10.4236/jasmi.2013.31001

Transmission of N-atoms (T N ) through small diameters tubes (1.5 and 3 mm internal diameter (i.d) and 9, 50 and 80 cm length for silicone tubes, 1.5 mm i.d and 6.5 cm length for stainless steel tubes) has been measured in late N2 and Ar-N2 flowing afterglows of microwave plasmas in continuous and pulsed gas injection at a flow rate of 1 and 3 Standard liter by minute (Slm), a gas pressure from 2 to 4 Torr for N2 and 20 Torr for Ar-1%N2 and a plasma power from 150 to 300 Watt. From the experimental TN values, it is deduced the γ-destruction probability inside the tube walls as being y = (1-1.6)×

Estimating the Global Burden of Snakebite Can Help To Improve Management
Jean-Philippe Chippaux
PLOS Medicine , 2008, DOI: 10.1371/journal.pmed.0050221
Le journal d’un ouvrier gaélophone en Grande-Bretagne : Différences culturelles et communauté linguistique
Jean-Philippe Hentz
Synergies Royaume-Uni et Irlande , 2008,
Abstract: Donall MacAmhlaigh est né en 1926 près de Galway, dans une région gaélophone de l’ouest de l’Irlande. Issu d’une famille modeste, il doit très t t commencer à travailler, d’abord comme ouvrier dans une usine textile puis, après la Seconde Guerre Mondiale, comme ouvrier de chantier itinérant, “navvy”, en Grande-Bretagne. Il a participé, comme de nombreux Irlandais de sa génération, à l’effort de reconstruction de la Grande-Bretagne d’aprèsguerre et a consigné cette expérience dans un journal écrit entre 1951 et 1957, et publié pour la première fois en 1964. Intitulé Dialann Deorai, en anglais An Irish Navvy : The Diary of an Exile, ce journal a été entièrement rédigé en gaélique, langue de prédilection de son auteur dont ce n’est cependant pas la langue maternelle.Ce journal, son contenu ou le choix de la langue d’écriture, posent d’emblée la question de la place de la langue gaélique non seulement en Irlande, mais aussi et surtout au sein des populations gaélophones émigrées, une question qui met en jeu tout un faisceau d’appartenances et de différences, aussi bien culturelles que sociales ou communautaires. En effet, tout au long de son récit, Donall MacAmhlaigh revient sans cesse sur l’importance de cette langue en tant que véhicule, mais également en tant que preuve, de son “irlandicité”, alors même que le milieu ouvrier irlandais de l’époque était très majoritairement urbain et anglophone et ne se reconnaissait par ailleurs que très peu dans ce type de revendication, très éloignée du quotidien auquel ces ouvriers étaient confrontés. Le journal fait donc état de différences culturelles et linguistiques à un double niveau : d’une part entre les ouvriers irlandais et britanniques, et d’autre part entre ouvriers irlandais anglophones et gaélophones. Ces différences peuvent d’ailleurs tourner à la confrontation, notamment entre les “jackeens”, les dublinois anglophones, et les “culchies”, les provinciaux, généralement gaélophones.Loin de l’idée d’une communauté irlandaise émigrée soudée, le journal de MacAmhlaigh montre au contraire les dissensions qui pouvaient exister au sein d’une telle communauté, dissensions fortement liées à l’emploi d’une langue plut t que d’une autre.
Varying Constants, Gravitation and Cosmology
Jean-Philippe Uzan
Living Reviews in Relativity , 2011,
Abstract: Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Conformally Equivariant Quantization - a Complete Classification
Jean-Philippe Michel
Symmetry, Integrability and Geometry : Methods and Applications , 2012,
Abstract: Conformally equivariant quantization is a peculiar map between symbols of real weight δ and differential operators acting on tensor densities, whose real weights are designed by λ and λ+δ. The existence and uniqueness of such a map has been proved by Duval, Lecomte and Ovsienko for a generic weight δ. Later, Silhan has determined the critical values of δ for which unique existence is lost, and conjectured that for those values of δ existence is lost for a generic weight λ. We fully determine the cases of existence and uniqueness of the conformally equivariant quantization in terms of the values of δ and λ. Namely, (i) unique existence is lost if and only if there is a nontrivial conformally invariant differential operator on the space of symbols of weight δ, and (ii) in that case the conformally equivariant quantization exists only for a finite number of λ, corresponding to nontrivial conformally invariant differential operators on λ-densities. The assertion (i) is proved in the more general context of IFFT (or AHS) equivariant quantization.
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