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Search Results: 1 - 10 of 117940 matches for " Beno?t Famaey "
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Modified Newtonian Dynamics (MOND): Observational Phenomenology and Relativistic Extensions
Benot Famaey,Stacy S. McGaugh
Living Reviews in Relativity , 2012,
Abstract: A wealth of astronomical data indicate the presence of mass discrepancies in the Universe. The motions observed in a variety of classes of extragalactic systems exceed what can be explained by the mass visible in stars and gas. Either (i) there is a vast amount of unseen mass in some novel form - dark matter - or (ii) the data indicate a breakdown of our understanding of dynamics on the relevant scales, or (iii) both. Here, we first review a few outstanding challenges for the dark matter interpretation of mass discrepancies in galaxies, purely based on observations and independently of any alternative theoretical framework. We then show that many of these puzzling observations are predicted by one single relation - Milgrom's law - involving an acceleration constant a_0 (or a characteristic surface density Σ_ = a_0∕G) on the order of the square-root of the cosmological constant in natural units. This relation can at present most easily be interpreted as the effect of a single universal force law resulting from a modification of Newtonian dynamics (MOND) on galactic scales. We exhaustively review the current observational successes and problems of this alternative paradigm at all astrophysical scales, and summarize the various theoretical attempts (TeVeS, GEA, BIMOND, and others) made to effectively embed this modification of Newtonian dynamics within a relativistic theory of gravity.
Masses of the components of SB2 binaries observed with Gaia. I. Selection of the sample and mass ratios of 20 new SB2s discovered with Sophie
Jean-Louis Halbwachs,Frédéric Arenou,Dimitri Pourbaix,Benot Famaey,Patrick Guillout,Yveline Lebreton,Jean-Baptiste Salomon,Lev Tal-Or,Rodrigo Ibata,Tsevi Mazeh
Physics , 2014, DOI: 10.1093/mnras/stu1838
Abstract: In anticipation of the Gaia astrometric mission, a large sample of spectroscopic binaries is being observed since 2010 with the Sophie spectrograph at the Haute--Provence Observatory. Our aim is to derive the orbital elements of double-lined spectroscopic binaries (SB2s) with an accuracy sufficient to finally obtain the masses of the components with relative errors as small as 1% when the astrometric measurements of Gaia are taken into account. Simultaneously, the luminosities of the components in the Gaia photometric band G will also be obtained. Our observation program started with 200 SBs, including 152 systems that were only known as single-lined. Thanks to the high efficiency of the Sophie spectrograph, an additional component was found for 25 SBs. After rejection of 5 multiple systems, 20 new SB2s were retained, including 8 binaries with evolved primary, and their mass ratios were derived. Our final sample contains 68 SB2s, including 2 late-type giants and 10 other evolved stars.
Matrix metalloproteinase-2 and -9 secretion by the human JAR choriocarcinoma cell line is stimulated by TNF-α  [PDF]
Benot Chénais
Advances in Bioscience and Biotechnology (ABB) , 2012, DOI: 10.4236/abb.2012.31009
Abstract: The JAR choriocarcinoma cell line share many of the characteristics of early placental trophoblast cells including the invasion properties. Matrix metallo-proteinases (MMPs), the main actors of matrix proteolysis, are involved in normal invasion as well as in the invasive character of tumor cells and the metastase formation. Tumor necrosis factor-α (TNF-α) is present in the placental environment and TNF-α levels are elevated in some placental pathologies. In the present work, we addressed whether TNF-α is a modulator of JAR cell MMP secretion. Following TNF-α stimulation, zymographic analysis showed the increased secretion of the active form of MMP-2 and to a lesser extent proMMP-2 and MMP-9. In addition, MMP-2 gene expression only increased slightly whereas MMP-9 and TIMP-1 transcripts were undetectable. This suggests that TNF-α may modulate the secretion of MMPs independently of MMP gene expression control.
Vectors for gene therapy: A place for DNA transposon  [PDF]
Benot Chénais
Open Journal of Genetics (OJGen) , 2013, DOI: 10.4236/ojgen.2013.32A1001

Gene therapy offers important perspectives in current and future medicine but suffers from imperfect vectors for the delivery of the therapeutic gene. Most preclinical and clinical trials have been based on the use of viral vectors, which have evident advantages but also some serious disadvantages. In the past decade the use of DNA transposon-based systems for gene delivery has emerged as a non-viral alternative. DNA transposon vector engineering remains largely in a preclinical phase but some interesting results have been obtained. This mini-review aims to provide the current state of the art on DNA transposon vectors used in a gene therapy perspective.

A Model for Probabilistic Reasoning on Assume/Guarantee Contracts
Benot Delahaye,Benot Caillaud
Computer Science , 2008,
Abstract: In this paper, we present a probabilistic adaptation of an Assume/Guarantee contract formalism. For the sake of generality, we assume that the extended state machines used in the contracts and implementations define sets of runs on a given set of variables, that compose by intersection over the common variables. In order to enable probabilistic reasoning, we consider that the contracts dictate how certain input variables will behave, being either non-deterministic, or probabilistic; the introduction of probabilistic variables leading us to tune the notions of implementation, refinement and composition. As shown in the report, this probabilistic adaptation of the Assume/Guarantee contract theory preserves compositionality and therefore allows modular reliability analysis, either with a top-down or a bottom-up approach.
-Carleson Measures for a Class of Hardy-Orlicz Spaces
Benot Florent Sehba
International Journal of Mathematics and Mathematical Sciences , 2011, DOI: 10.1155/2011/926527
Abstract: An alternative interpretation of a family of weighted Carleson measures is used to characterize -Carleson measures for a class of Hardy-Orlicz spaces admitting a nice weak factorization. As an application, we provide with a characterization of symbols of bounded weighted composition operators and Cesàro-type integral operators from these Hardy-Orlicz spaces to some classical holomorphic function spaces. 1. Introduction Hardy-Orlicz spaces are the generalization of the usual Hardy spaces. We raise the question of characterizing those positive measures defined on the unit ball of such that these spaces embed continuously into the Lebesgue spaces . More precisely, let denote by the Lebesgue measure on and the normalized measure on the unit sphere which is the boundary of . denotes the space of holomorphic functions on . Let be continuous and nondecreasing function from onto itself. That is, is a growth function. The Hardy-Orlicz space is the space of function in such that the functions , defined by satisfy We denote the quantity on the left of the above inequality by or simply when there is no ambiguity. Let us remark that , where denotes the Luxembourg (quasi)-norm defined by Given two growth functions and , we consider the following question. For which positive measures on , the embedding map , is continuous? When and are power functions, such a question has been considered and completely answered in the unit disc and the unit ball in [1–6]. For more general convex growth functions, an attempt to solve the question appears in [7], in the setting of the unit disc where the authors provided with a necessary condition which is not always sufficient and a sufficient condition. The unit ball version of [7] is given in [8]. To be clear at this stage, let us first introduce some usual notations. For any and , let These are the higher dimension analogues of Carleson regions. We take as the power functions, that is, for . Thus, the question is now to characterize those positive measures on the unit ball such that there exists a constant such that We call such measures -Carleson measures for . We give a complete answer for a special class of Hardy-Orlicz spaces with , . For simplicity, we denote this space by . We prove the following result. Theorem 1.1. Let and . Then the following assertions are equivalent. (i)There exists a constant such that for any and , (i)There exists a constant such that To prove the above result, we combine weak-factorization results for Hardy-Orlicz spaces (see [9, 10]) and some equivalent characterizations of weighted Carleson measures
Bench-to-bedside review: Endothelial cell dysfunction in severe sepsis: a role in organ dysfunction?
Benot Vallet
Critical Care , 2002, DOI: 10.1186/cc1864
Abstract: The vascular endothelium regulates the flow of nutrient substances, diverse biologically active molecules and the blood cells themselves. This role of endothelium is achieved through the presence of membrane-bound receptors for numerous molecules, including proteins, lipid transporting particles, metabolites and hormones, as well as through specific junction proteins and receptors that govern cell–cell and cell–matrix interactions [1,2]. Endothelial dysfunction and/or injury with subendothelium exposure facilitates leucocyte and platelet aggregation, and aggravation of coagulopathy. Therefore, endothelium dysfunction and/or injury should favour impaired perfusion, tissue hypoxia and subsequent organ dysfunction.The present review describes, within the context of sepsis, why altered endothelial properties may be suspected to be involved in organ failure (Table 1).Endothelial injury describes a state in which microscopically visible endothelial cell (EC) shape change or injury can be identified, as well as defects in endothelial lining or elevated soluble markers of endothelial injury [3]. Anatomical damage to the endothelium during septic shock has been assessed in several studies [4,5,6]. A single injection of bacterial lipopolysaccharide (LPS) has long been demonstrated to be a nonmechanical technique for removing endothelium [5]. In endotoxic rabbits, observations tend to demonstrate that EC surface modification occurs easily and rapidly [5,6], with ECs being detached from the internal elastic lamina with an indication of subendothelial oedema. As early as 15 min after LPS injection [7] cellular injuries are apparent, with nuclear vacuolization, cytoplasmic swelling and protrusion, cytoplasmic fragmentation, and various degrees of detachment of the endothelium from its underlying layer. This can also be observed 10 hours after the onset of sepsis in a caecal ligation and puncture rat model [8]. Proinflammatory cytokines increase permeability of the Ecs, and this i
Le potentiel d'innovation et de transformation de l'économie sociale: quelques éléments de problématique
Lévesque, Benot;
Intera??es (Campo Grande) , 2008, DOI: 10.1590/S1518-70122008000200008
Abstract: à la question, ? les entreprises d'économie sociale sont-elles plus porteuses d'innovations sociales que les autres? ?, une réponse positive est avancée assez spontanément, aussi bien par les promoteurs que par la plupart des chercheurs s'y intéressant. à partir de recherches que nous avons réalisées individuellement ou en équipe et en tenant compte des études que nous avons pu consulter dans le cadre de nos travaux sur l'économie sociale, nous tentons d'avancer quelques éléments de problématique pour répondre à nouveau à cette question. dans un premier temps, nous revenons sur ce qu'il faut entendre par innovation sociale, étant donné que c'est le plus souvent en référence à ce type d'innovation que l'économie sociale est considérée. dans un deuxième temps, nous examinons les approches théoriques, notamment les définitions de l'économie sociale, et dans un troisième temps les recherches empiriques. sous l'angle des approches théoriques, le potentiel d'innovation de l'économie sociale est évalué, sans grande nuance, comme très élevé ou au contraire comme très faible. dans un cas, il s'agit des approches théoriques relevant, entre autres, de la sociologie, de l'économie politique ou encore des hétérodoxes en économie, qui définissent l'économie sociale comme contrainte à innover puisqu'elle tente de répondre à des besoins voire des aspirations non satisfaits par le marché ou l'état. dans l'autre cas, il s'agit des approches néoclassiques qui ne retrouvent dans l'économie sociale, ni la propriété individuelle, ni le profit, qui représentent selon eux les principaux ressorts de l'innovation. selon les approches empiriques, les évaluations sont plus nuancées tenant compte, entre autres, des phases de développement. si la création est généralement l'occasion d'innover, la diffusion puis le développement conduisent souvent, mais non inexorablement, à la banalisation, à l'isomorphisme institutionnel voire à la privatisation. les études de cas qui ont porté surtout sur des
Qualification of the adaptive capacities of livestock farming systems
Dedieu, Benot;
Revista Brasileira de Zootecnia , 2009, DOI: 10.1590/S1516-35982009001300039
Abstract: this paper aims at exploring what is covered by ? adapting to last ? with a farming systems approach. long term dynamics can be analysed as adaptive cycles, the system being permanently exposed to disturbances and shocks. mobilizing the concept of resilience, we analyse the factors that differentiate the principles for long term action the livestock farmers have, principles which give consistency to the family - farms trajectories. with the concept of operational flexibilty, we qualify the sources of flexibility the livestock farmers maintain to cope with hazards. they are internal, related to the production process regulation properties, to the technical (adaptive or rigid) specifications, to the sales policies, or external related to the information and commercial networks. understanding the production process regulation properties require livestock farming systems models (i.e. combining decisional and biological sub-systems) that can simulate how herd dynamics operate under fluctuant rules or productive parameters. it also require to evaluate the room for manoeuvre the work organization let to the farmer. all these aspects are illsutrated with on farm studies in herbivore systems (sheep, dairy, beef).
Contribui??o da nova sociologia econ?mica para repensar a economia no sentido do desenvolvimento sustentável
Lévesque, Benot;
Revista de Administra??o de Empresas , 2007, DOI: 10.1590/S0034-75902007000200006
Abstract: this article deals with the new economic sociology's (nes) occasional contribution to the sociology of sustainable development. beginning in the 1980s, the nes proposes to understand the economy as a social totality, including the sustainable development approach. moreover, by considering the economy from the perspective of institutions, organizations, networks and governance modes, this view once again places the economy at the heart of society, which would be a minor development if this conception were already acknowledged by our society and even by our disciplines. our documental research is conducted in two stages. the first part discusses the emergence of nes. in the second part we examine various approaches that propose the reconstruction of the economy as a sociological subject. finally, we raise questions regarding what is possible to apprehend from these approaches, looking for a better understanding of the sustainable development.
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