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Search Results: 1 - 9 of 9 matches for " An Herreman "
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Arquitectura y museología: del MOMA al Guggenheim de Bilbao o los inicios del museo moderno y su arquitectura
Herreman, Yani;
Alteridades , 2009,
Abstract: the dialectical relationship between museology, architecture and society produces the social construct called museum. the first two, as part of society's cultural, economic and political movements, mirror society. the years prior to and following world war ii, when the new concept of a modern museum appears and adopts the architectural trends of the moment, are the focus of this essay. the museum building has been transformed at an unprecedented speed since the 80's, both conceptually and formally, giving the researcher unique study opportunities.
La mise en texte mathématique.
Alain Herreman
Methodos : Savoirs et Textes , 2004, DOI: 10.4000/methodos.45
Abstract: L’auteur commence par rappeler la diversité d’aspects des textes mathématiques. Il s’appuie pour cela sur plusieurs études historiques récentes consacrées à l’analyse et aux conséquences de cette diversité dans le cas des mathématiques babyloniennes, grecques et chinoises. Il propose ensuite une analyse sémiotique de la transcription de l’un des textes latins par lesquels l’arithmétique fondée sur les chiffres arabes a été diffusée en Occident. La comparaison des résultats obtenus avec ceux de la même analyse appliquée à la traduction fran aise qui a récemment été donnée de ce texte lui permet de comparer l’évolution de la forme des textes mathématiques avec l’évolution des caractéristiques sémiotiques des nombres. Au cours de cet article, il propose un rapprochement entre le type de mise en texte adoptée et certains préjugés formalistes. The author starts by reminding the diversity of aspects of mathematical texts. To this purpose, he backs up his theories on several recent historical studies devoted to the analysis and to the consequences of this diversity as for Babylonian, Greek and Chinese mathematics. Then, he proposes a semiotic analysis of one of the Latin texts’ transcription thanks to which the arithmetic based on Arabic ciphers was introduced in the West. The comparison of the results with those of the same analysis applied to the French translation of this text that has just been issued allows him to compare the evolution of the form of mathematical texts to the evolution of the semiotical characteristics of ciphers. In the course of this article, he proposes a connection both between the type of text setting and some formalist prejudices.
Remarques sur l'expression de la généralité en mathématiques
Alain Herreman
Mathematics , 2009,
Abstract: This paper gives a condition of the expression of generality in mathematics from the application of L\"owenheim-Skolem theorem to Zermelo's axioms. It gives an example of an "expression problem" from Gauss's Disquisitiones Arithmeticae and caracterizes the used of sets in it.---L'article d\'egage une condition de l'expression de la g\'en\'eralit\'e en math\'ematiques \`a partir de l'application du th\'eor\`eme de L\"owenheim-Skolem aux axiomes de Zermelo. Il donne un exemple de "probl\`eme d'expression" \`a partir des Disquisitiones Arithmeticae de Gauss, d\'egageant ainsi une condition du recours aux ensembles.
L'inauguration des séries trigonométriques dans la Théorie analytique de la chaleur de Fourier et dans la controverse des cordes vibrantes
Alain Herreman
Mathematics , 2012,
Abstract: Cet article applique les notions de texte et d'\'enonc\'e inaugural \`a la Th\'eorie analytique de la chaleur de Fourier et \`a la controverse des cordes vibrantes. Il \'etablit que seul le livre de Fourier est un texte inaugural. Il propose en outre une analyse s\'emiotique des modes d'expression de la g\'en\'eralit\'e qui permet dans chaque cas de clarifier les conditions d'introduction de la possibilit\'e de repr\'esenter une fonction arbitraire par des s\'eries trigonom\'etriques. (The inauguration of trigonometrical series in Fourier's Th\'eorie analytique de la chaleur and in the vibrating strings controversy) This paper applies the notions of inaugural text and statement to Fourier's Th\'eorie analytique de la chaleur and to the vibrating strings controversy. It establishes that only Fourier's book is an inaugural text. It presents also a semiotic analysis of the expression modes of generality which allows to clarify in both cases the conditions of introducing of the possibility to represent an arbitrary function by trigonometrical series.
Un énoncé et un texte inaugural
Alain Herreman
Mathematics , 2011,
Abstract: This paper shows that the main features of Turing's thesis derived from those of the expression system (Turing machines) it inaugures, and in particular its conformity. The notions of inaugural statements and texts are defined and illustrated by other examples than Turing thesis and article. Other relationships between the inaugural texts are considered which allow to include Turing's article in an inaugural history.
Libration driven multipolar instabilities
David Cébron,Stijn Vantieghem,Wietze Herreman
Physics , 2014, DOI: 10.1017/jfm.2013.623
Abstract: We consider rotating flows in non-axisymmetric enclosures that are driven by libration, i.e. by a small periodic modulation of the rotation rate. Thanks to its simplicity, this model is relevant to various contexts, from industrial containers (with small oscillations of the rotation rate) to fluid layers of terrestial planets (with length-of-day variations). Assuming a multipolar $n$-fold boundary deformation, we first obtain the two-dimensional basic flow. We then perform a short-wavelength local stability analysis of the basic flow, showing that an instability may occur in three dimensions. We christen it the Libration Driven Multipolar Instability (LDMI). The growth rates of the LDMI are computed by a Floquet analysis in a systematic way, and compared to analytical expressions obtained by perturbation methods. We then focus on the simplest geometry allowing the LDMI, a librating deformed cylinder. To take into account viscous and confinement effects, we perform a global stability analysis, which shows that the LDMI results from a parametric resonance of inertial modes. Performing numerical simulations of this librating cylinder, we confirm that the basic flow is indeed established and report the first numerical evidence of the LDMI. Numerical results, in excellent agreement with the stability results, are used to explore the non-linear regime of the instability (amplitude and viscous dissipation of the driven flow). We finally provide an example of LDMI in a deformed spherical container to show that the instability mechanism is generic. Our results show that the previously studied libration driven elliptical instability simply corresponds to the particular case $n=2$ of a wider class of instabilities. Summarizing, this work shows that any oscillating non-axisymmetric container in rotation may excite intermittent, space-filling LDMI flows, and this instability should thus be easy to observe experimentally.
Influence of high permeability disks in an axisymmetric model of the Cadarache dynamo experiment
A. Giesecke,C. Nore,F. Stefani,G. Gerbeth,J. Léorat,W. Herreman,F. Luddens,J. -L. Guermond
Physics , 2011, DOI: 10.1088/1367-2630/14/5/053005
Abstract: Numerical simulations of the kinematic induction equation are performed on a model configuration of the Cadarache von-K\'arm\'an-Sodium dynamo experiment. The effect of a localized axisymmetric distribution of relative permeability {\mu} that represents soft iron material within the conducting fluid flow is investigated. The critical magnetic Reynolds number Rm^c for dynamo action of the first non-axisymmetric mode roughly scales like Rm^c({\mu})-Rm^c({\mu}->infinity) ~ {\mu}^(-1/2) i.e. the threshold decreases as {\mu} increases. This scaling law suggests a skin effect mechanism in the soft iron disks. More important with regard to the Cadarache dynamo experiment, we observe a purely toroidal axisymmetric mode localized in the high permeability disks which becomes dominant for large {\mu}. In this limit, the toroidal mode is close to the onset of dynamo action with a (negative) growth-rate that is rather independent of the magnetic Reynolds number. We qualitatively explain this effect by paramagnetic pumping at the fluid/disk interface and propose a simplified model that quantitatively reproduces numerical results. The crucial role of the high permeability disks for the mode selection in the Cadarache dynamo experiment cannot be inferred from computations using idealized pseudo-vacuum boundary conditions (H x n = 0).
Notch Is a Critical Component of the Mouse Somitogenesis Oscillator and Is Essential for the Formation of the Somites
Zoltan Ferjentsik,Shinichi Hayashi equal contributor,J. Kim Dale equal contributor,Yasumasa Bessho,An Herreman,Bart De Strooper,Gonzalo del Monte,Jose Luis de la Pompa,Miguel Maroto
PLOS Genetics , 2009, DOI: 10.1371/journal.pgen.1000662
Abstract: Segmentation of the vertebrate body axis is initiated through somitogenesis, whereby epithelial somites bud off in pairs periodically from the rostral end of the unsegmented presomitic mesoderm (PSM). The periodicity of somitogenesis is governed by a molecular oscillator that drives periodic waves of clock gene expression caudo-rostrally through the PSM with a periodicity that matches somite formation. To date the clock genes comprise components of the Notch, Wnt, and FGF pathways. The literature contains controversial reports as to the absolute role(s) of Notch signalling during the process of somite formation. Recent data in the zebrafish have suggested that the only role of Notch signalling is to synchronise clock gene oscillations across the PSM and that somite formation can continue in the absence of Notch activity. However, it is not clear in the mouse if an FGF/Wnt-based oscillator is sufficient to generate segmented structures, such as the somites, in the absence of all Notch activity. We have investigated the requirement for Notch signalling in the mouse somitogenesis clock by analysing embryos carrying a mutation in different components of the Notch pathway, such as Lunatic fringe (Lfng), Hes7, Rbpj, and presenilin1/presenilin2 (Psen1/Psen2), and by pharmacological blocking of the Notch pathway. In contrast to the fish studies, we show that mouse embryos lacking all Notch activity do not show oscillatory activity, as evidenced by the absence of waves of clock gene expression across the PSM, and they do not develop somites. We propose that, at least in the mouse embryo, Notch activity is absolutely essential for the formation of a segmented body axis.
Quercetin Induces Hepatic Lipid Omega-Oxidation and Lowers Serum Lipid Levels in Mice
Elise F. Hoek-van den Hil, Jaap Keijer, Annelies Bunschoten, Jacques J. M. Vervoort, Barbora Stankova, Melissa Bekkenkamp, Laure Herreman, Dini Venema, Peter C. H. Hollman, Eva Tvrzicka, Ivonne M. C. M. Rietjens, Evert M. van Schothorst
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0051588
Abstract: Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and 1H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (p<0.001) and total poly unsaturated fatty acids (PUFA) were increased with 13% (p<0.01). Palmitic acid, oleic acid, and linoleic acid were all decreased by 9–15% (p<0.05) in quercetin-fed mice. Both palmitic acid and oleic acid can be oxidized by omega (ω)-oxidation. Gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially ω-oxidation. At the gene level, this was reflected by the up-regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3) were also up-regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid ω-oxidation and lowered corresponding circulating lipid levels, which may contribute to potential beneficial effects on CVD.
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