Displacements by Successive rotations for Vehicles Subject to Given Constraints

The displacements of a vehicle on a plane can be subject to constraints depending on the nature of the vehicle. One can, for instance, think of the existence of a smallest turning circle for a car. In this paper our purpose is to show, on a simple example, how such constraints can be handled. We, in fact, consider the case of a vehicle the motions of which consist of a finite sequence of rotations, each rotation being subject to the following constraints. 1) The radius of the circles along which the displacements of the vehicle take place are larger than a critical radius. 2) The centers of the successive rotations are located along a straight line defined by the geometry of the vehicle. The mathematical analysis of this problem relies on a suitable choice of frames of reference in which the expression of the constraints is particularly simple. It is then shown that, under the above constraints, an arbitrary displacement can always be achieved by three approriate rotation

Long-term uncertainty of hydropower revenue due to climate change and electricity prices

Hydropower represents the world’s largest renewable energy source. As a flexible technology, it enhances reliability and security of the electricity system. However, climate change and market liberalization may hinder investment due to the evolution of water runoffs and electricity prices. Both alter expected revenue and bring uncertainty. It increases risk and deters investment. Our research assesses how climate change and market fluctuation affect annual revenue. But this paper focuses on the uncertainty, rather than on forecasting. This transdisciplinary topic is investigated by means of a mixed method, i.e. both quantitative and qualitative. The quantitative approach uses established models in natural sciences and economics. The uncertainty is accounted for by applying various scenarios and various datasets coming from different models. Based on those results, uncertainty is discussed through an analysis discerning three dimensions of uncertainty. Uncertainty analysis requires the assessment of a large panel of models and data sets. It is therefore rarely carried out. The originality of the paper also lies on the combination of quantitative established models with a qualitative analysis. The results surprisingly show that the greenhouse gas scenarios may in fact represent a low source of uncertainty, unlike electricity prices. Like forecasting, the main uncertainties are actually case study related and depend on the investigated variables. It is also shown that the nature of uncertainty evolves. Runoff uncertainty goes from variability, i.e. inherent randomness, to epistemic, i.e. limitation of science. The reverse situation occurs with the electricity price. The implications for scientists and policy makers are discussed

Interferon- α 2b reduces phosphorylation and activity of MEK and ERK through a Ras / Raf -independent mechanism

Interferon (IFN)-α affects the growth, differentiation and function of various cell types by transducing regulatory signals through the Janus tyrosine kinase/signal transducers of activation and transcription (Jak/STAT) pathway. The signalling pathways employing the mitogen-activated ERK-activating kinase (MEK) and the extracellular-regulated kinase (ERK) are critical in growth factors signalling. Engagement of the receptors, and subsequent stimulation of Ras and Raf, initiates a phosphorylative cascade leading to activation of several proteins among which MEK and ERK play a central role in routing signals critical in controlling cell development, activation and proliferation. We demonstrate here that 24–48 h following treatment of transformed T- and monocytoid cell lines with recombinant human IFN-α2b both the phosphorylation and activity of MEK1 and its substrates ERK1/2 were reduced. In contrast, the activities of the upstream molecules Ras and Raf -1 were not affected. No effect on MEK/ERK activity was observed upon short-term exposure (1–30 min) to IFN. The anti-proliferative effect of IFN-α was increased by the addition in the culture medium of a specific inhibitor of MEK, namely PD98059. In conclusion, our results indicate that IFN-α regulates the activity of the MEK/ERK pathway and consequently modulates cellular proliferation through a Ras / Raf -independent mechanism. Targeting the MEK/ERK pathway may strengthen the IFN-mediated anti-cancer effect. © 2000 Cancer Research Campaig

Fiction et révélation : Vous les entendez ? De Nathalie Sarraute

Notre étude porte sur l’ouvrage de Nathalie Sarraute Vous les entendez ? (1972). Nous entendons montrer la puissance heuristique de la création fictionnelle qu’y réalise l’auteure : son dispositif romanesque original permet de révéler une réalité originaire inaperçue et presque imperceptible, qui échappe à une appréhension strictement phénoménologique et ne peut donc être découverte qu’en étant inventée.Vous les entendez ? est sans doute le roman le plus complexe de N. Sarraute. Sa fragmentation textuelle a pour objet, non pas seulement de rompre avec le genre « classique » du roman, notamment avec le déroulement d’une longue durée, mais surtout de mettre en forme la progressive dilatation d’une brève durée, à savoir quelques instants, apparemment insignifiants, vécus par un père et ses enfants. À mesure que le texte les dilate, il développe les fugaces impressions qui y sont éprouvées : de la sorte, il rend visible leur contenu invisible et met au jour des niveaux d’expérience de plus en plus primordiaux où les sujets perdent leurs contours et apparaissent tels qu’ils sont dans leur expérience irréfléchie, des pré-sujets indifférenciés et inséparés entre lesquels « une même substance circule librement ».Pour analyser ce dispositif et saisir ce qu’il révèle, nous nous appuierons sur un corpus d’ouvrages délibérément interdisciplinaires : des ouvrages philosophiques qui exposent des conceptions de la conscience ou de l’originaire proches de la vision sarrautienne (la théorie des états de conscience d’Henri Bergson, l’analyse phénoménologique du sentir et l’ontologie de l’Etre invisible de Maurice Merleau-Ponty) et des ouvrages linguistiques, sémiologiques et narratologiques qui permettent d’éclairer, sous différents angles, les procédés discursifs au moyen desquels l’auteure déconstruit les sujets de conscience et construit un « équivalent littéraire » de ce qu’elle appelle « substance ».This article studies Nathalie Sarraute’s novel Vous les entendez ? (1972). I want to show the heuristic power of the author’s fictional creation: her new approach to fiction reveals an original reality both unseen and almost imperceptible that avoids a strictly phenomenological understanding, and thus can only be discovered by being created.Vous les entendez ? is probably N. Sarraute’s most complex novel. Its textual fragmentation aims not only to break with the “classical” genre of the novel – particularly with the unfolding of a long length of time – but also to provide a shape for the progressive distension of a short period of time: a few, seemingly insignificant moments lived by a father and his kids. As the text dilates them, it develops the fleeting feelings that the characters experience, and thus make visible their invisible content. It also reveals levels of experience which are more and more primordial, where the subjects lose their shapes and appear as they are in their thoughtless experience, pre-subjects indistinguishable and inseparated, between whom “the same substance runs freely”.To analyze this device and understand what it reveals, I will rely on a deliberately interdisciplinary corpus: philosophical works which present conceptions of consciousness or of the original close to the sarrautian vision (Henri Bergson’s theory of the states of consciousness, Maurice Merleau-Ponty’s phenomenological analysis of feeling and ontology of the invisible Being), and linguistic, semiological and narratological works that can enlighten in different ways the discursive devices with which the author deconstructs the subjects of consciousness and constructs a “literary equivalent” to what she calls “substance.

On Long-Range Order in Low-Dimensional Lattice-Gas Models of Nematic Liquid Crystals

The problem of the orientational ordering transition for lattice-gas models of liquid crystals is discussed in the low-dimensional case $d=1,2$. For isotropic short-range interactions, orientational long-range order at finite temperature is excluded for any packing of molecules on the lattice $Z^d$; on the other hand, for reflection-positive long-range isotropic interactions, we prove existence of an orientational ordering transition for high packing ($\mu > \mu_0$) and low temperatures ($\beta > \beta_c(\mu)$).Comment: 11 page

Vie d’un vulnérable : l’homme qui a tué Antoine Lazenec

Dans Article 353 du code pénal (2017), la fragilité qui caractérise les personnages de Tanguy Viel est convertie en vulnérabilité, c’est-à-dire en une exposition aux menaces que la situation géographique, sociale et politique fait peser non pas seulement sur un individu mais sur toute une communauté, un village brestois ; le personnage-narrateur en est le membre le plus éprouvé : un ouvrier divorcé au chômage dont le fils devient délinquant. Nous étudions l’incidence de cette conversion sur la constitution du monde fictif, qui est socialisé, et sur la forme du récit, dont la possibilité même est en jeu. L’auteur représente mais aussi configure la vulnérabilité au moyen d’une double intrigue (une intrigue policière dans une intrigue judiciaire) ; il lui donne cependant un dénouement par surprise qui rompt avec le régime référentiel de son dispositif. Nous interrogeons la paradoxalité de cette fin qui éloigne le monde fictif du monde réel pour en proposer une légende.In Article 353 of the Criminal Code (2017), the fragility which characterizes the characters of Tanguy Viel is converted into vulnerability, that is to say, an exposure to threats which the geographical, social and political situation poses not only over an individual but over an entire community, a village in Brest ; the character-narrator is the most afflicted member : a unemployed divorced worker whose son becomes a delinquent. We study the impact of this conversion on the constitution of the fictional world, which is socialized, and on the form of the narrative, the very possibility of which is at stake. The author represents but also configures the vulnerability by means of a double intrigue (a police intrigue in a judicial intrigue) ; however, it gives it a surprising ending that breaks with the referential regime of its system. We question the paradoxical nature of this end which takes the fictional world away from the real world to offer a legend

Inverse correlation between endothelin-1-induced peripheral microvascular vasoconstriction and blood pressure in glaucoma patients

• Background: The potent vasoconstrictor peptide endothelin-I has been shown to participate in the control of peripheral vascular tone and in the regulation of ocular perfusion. In glaucoma patients vasospasms and arterial hypotension have been identified as risk factors for the progression of glaucomatous damage, and the regulation of endothelin-1 release is disturbed in some of these patients. The aim of this study was to assess the relationship between resting blood pressure and cutaneous vascular responsiveness to endothelin-1 and phenylephrine in patients with glaucoma and in matched controls. • Methods: In 9 patients with primary open-angle glaucoma (POAG), 7 patient with normal tension glaucoma (NTG), and 16 age- and sex-matched controls, endothelin-1 and phenylephrine responses were assessed in the human forearm microcirculation using laser Doppler flowmetry during intra-arterial drug administration. Blood pressure was measured intra-arterially. • Results: In contrast to α1-adrenergic effects, endothelin-1 responses were inversely correlated to both systolic (r 2 = 0.27,P = 0.05) and diastolic (r 2 = 0.54,P = 0.001) blood pressure in glaucoma patients, whereas there was no such correlation in controls. Patients with lower blood pressure values were more sensitive to the vasoconstrictor effects of endothelin-1. Cutaneous responsiveness to endothelin-1 and phenylephrine was similar in glaucoma patients and in controls. • Conclusion: These results reveal that glaucoma patients appear to have peripheral microvascular abnormalities which are exhibited as altered responsiveness to endothelin-1. Thus, this study supports the hypothesis that endothelin-l-related microvascular dysfunction may be involved in the pathogenesis of glaucomatous damag

Umwelt, Entwicklung und Zusammenarbeit : eine Standortbestimmung

1. Einleitung Bis zu Beginn der siebziger Jahre galt die Sorge um die Umweltqualität als Luxus, den sich die Entwicklungsländer schlicht und einfach nicht leisten konnten. Anlässlich der Konferenz der Vereinten Nationen in Stockholm im Jahre 1972 machte sich die indische Premierministerin Indira Gandhi zur Sprecherin zahlreicher Entwicklungsländer, indem sie erklärte : „Wie kann man von den Bewohnern der Dörfer und Slums verlangen, sie sollten etwas gegen die Verschmutzung der Luft, der Flüss..