Scaling transformation and probability distributions for financial time series

The price of financial assets are, since Bachelier, considered to be described by a (discrete or continuous) time sequence of random variables, i.e a stochastic process. Sharp scaling exponents or unifractal behavior of such processes has been reported in several works. In this letter we investigate the question of scaling transformation of price processes by establishing a new connexion between non-linear group theoretical methods and multifractal methods developed in mathematical physics. Using two sets of financial chronological time series, we show that the scaling transformation is a non-linear group action on the moments of the price increments. Its linear part has a spectral decomposition that puts in evidence a multifractal behavior of the price increments.Comment: 10 pages, 4 figures, latex and ps file

Sur la migration de l’Arsenic dans le milieu naturel

Bastisse Etienne-Marcel. Sur la migration de l’arsenic dans le milieu naturel. In: Bulletin de l'Académie Vétérinaire de France tome 120 n°5, 1967. pp. 261-265

Before It’s Too Late:Preventing Genocide by Holding the Territorial State Responsible for Not Taking Preventive Action

It is widely accepted in international law that the responsibility of states for the breach of an obligation to prevent a given event occurs when that event takes place. When applied to the obligation to prevent genocide, it would mean that the breach of that obligation commences when genocide occurs. If that is the case, this would appear to be in conflict with the aim of the rules on the responsibility of states and the aim of the primary rule on the obligation to prevent genocide. This conflict has not been fully addressed in the literature. This contribution examines whether and to what extent under the existing rules of international law on the prevention of genocide it is possible to hold territorial states responsible for the breach of that obligation before genocide occurs or never occurs. It will be argued that international law does not provide a general rule which is applicable to all obligations to prevent and that the moment of the breach depends on the content and nature of each obligation and the event to be prevented. The nature and content of the obligation to prevent genocide dictates that its breach commences at the moment a state fails to do what that obligation requires it to do and not at the moment genocide is committed. The legal consequences of state responsibility for not taking measures to prevent genocide as well as the invocation of the responsibility are addressed, leading to the conclusion that an international mechanism seems to be required to effectively implement the responsibility of the territorial state to prevent genocide

Le positionnement des villes belges dans le réseau global des services avancés

Reprenant les concepts et méthodes issus des travaux sur les réseaux de villes globales, cet article a pour but de présenter une hiérarchie urbaine belge sous un nouveau regard, issu de l’analyse de la présence de firmes de services avancés à la production.Après avoir sélectionné une dizaine de centres urbains majeurs, en apportant une attention particulière au cas de la Région de Bruxelles-Capitale et de sa très dynamique périphérie flamande autour de Zaventem, les niveaux de connexions de chaque ville ont été évalués, tant à l’échelle nationale qu’internationale.Mise à part la domination de Bruxelles (et Anvers dans une moindre mesure), les positions de certaines villes belges apparaissent étonnantes. Par ailleurs, la hiérarchie se modifie selon l’échelle de travail (connectivités nationales ou internationales) et selon les secteurs. Ceci aide à comprendre les rapports des villes belges entre elles ainsi qu’au niveau international et la division géographique du travail qui se met en place dans la distribution des services avancés.Starting from the concepts and methods developed by research on global cities networks, this article aims at presenting a new Belgian urban hierarchy, based on the analysis of the presence of advanced production services firms.About ten major urban centres have been selected (with particular attention to the Brussels-Capital Region and its highly dynamic Flemish periphery around Zaventem) and their connection level assessed from a national and international point of view.Aside from Brussels’ (and to a lesser extent Antwerp’s) predominance, the positions of some Belgian cities appear amazing. Moreover, the hierarchy changes according to level (national or international connectivity) and sector. This helps to understand Belgian cities’ connections, both at national and international level, as well as the new geographical division of labour in the distribution of advanced services

Réaffectation urbaine et développement socio-économique

Le site de Tour et Taxis, friche industrielle d’une trentaine d’ha située en plein centre de l’agglomération bruxelloise, fait l’objet d’un important projet de réaffectation qui s’inscrit dans un schéma devenu classique de politique de remodelage urbain. Les projets-phares ou « flagship projects », opérations de rénovation et de construction urbaines de grande ampleur, de haut standing et d’une visibilité qui se veut internationale, ont l’ambition de dynamiser l’image des villes occidentales afin d’attirer de nouveaux investissements internationaux dans les secteurs économiques de pointe. Le projet de « Cité de la Science et de la Connaissance » sur le site de Tour et Taxis entre dans cette logique. Bénéficiant de la présence de bâtiments architecturalement remarquables, il est axé sur les hautes technologies, tant du point de vue de la formation (grande école d’ingénieur) que des activités économiques (attraction d’entreprises secondaires et tertiaires innovantes, incubateurs d’entreprises) et culturelles (musée interactif techno-scientifique, centre de congrès). Après avoir synthétisé, sur la base d’expériences étrangères, les enjeux suscités par les flagships, l’article examine les conditions selon lesquelles le projet pourrait être porteur de développement économique, tant pour la Région de Bruxelles-Capitale que pour le quartier. L’article analyse ensuite les risques sociaux que le projet fait peser sur le quartier contigu au site, actuellement en situation socio-économique fragile. En définitive, les auteurs plaident pour la mise en œuvre conjointement au projet immobilier, d’une série de mesures d’accompagnement visant d’une part, à pérenniser les activités économiques ciblées par un ancrage dans le tissu économique local et d’autre part, à maîtriser la polarisation sociale locale de manière à éviter les phénomènes d’exclusion et de gentrification.The « Tour et Taxis » site, an industrial wasteland of about 30 ha in the centre of the Brussels urban area, is the place of a huge reallocation project within the framework of a now classic pattern of urban remodeling policy. The flagship projects, aimed at vast luxury urban renovation and building operations with international visibility, claim to revitalize the image of Western cities in order to attract new international investments in the leading economic sectors. The « City of science and knowledge » on the « Tour et Taxis » site, fits into the same scheme. Thanks to the presence of architecturally remarkable buildings, it is based upon high technologies, whether regarding educational (Grande École of engineering), economic (it attracts innovative enterprises from the secondary and tertiary sectors, business incubators) or cultural activities (interactive techno-scientific museum, congress centre).After having summarized, on the basis of foreign experiments, the stakes linked to the flagships, the article examines the conditions under which the project could bring about economic development, so much for the Brussels-Capital Region as for the district itself. The article also analyses the social risks threatening the adjoining neighbourhood, presently in precarious socioeconomic situation. Finally, the authors plead for the creation, in parallel with the building project, of a range of supporting measures aiming, on the one hand, at perpetuating the targeted economic activities through anchoring them in the local economy and, on the other hand, getting the local social polarization under control so as to avoid exclusion and gentrification phenomena

Reconstruction of randomly and partially sampled STEM spectrum-images

Scanning transmission electron microscopy (STEM) offers the ability to acquire several single- and multi-channels signals generated simultaneously for each probe position: cathodoluminescence (CL), electron energy loss spectroscopy (EELS) and high-angle annular dark-field imaging (HAADF). However, in some cases, sensitive samples (e.g., biological samples or molecular structures) may suffer from irradiation damages during acquisition. As a consequence, it is often necessary to reduce probe current or dwell time, which could significantly lower the signal-to-noise ratio. Another approach consists in acquiring only a subset of pixels randomly chosen in a given region of interest. This particular experimental set-up has been implemented on the STEM VG HB501 (LPS, Orsay, France), with the beam following a predetermined random path. The reconstruction of HAADF images is then straightforward with well known algorithms. However, when reconstructing the associated spectrum image, the high number of energy bands makes the problem computationally expensive

Solar Atlas for the Southern and Eastern Mediterranean

International audienceSouthern and eastern Mediterranean regions are prone to production of electricity by solar systems. The solar resource is the "fuel" of such systems and its availability is a key economic parameter in system design. Even though the southern and eastern Mediterranean region is served by several commercial data providers, in a public domain, so far only coarse resolution (100 km) data or data with limited temporal coverage is available. For more rapid development of policies and to attract the industrial interest in this region a more enhanced and easy to access free information is needed. The project will bring high resolution (1 km), long term coverage of at least 15 years data on the available solar resources for the region covering the countries Syria, Jordan, Israel, Lebanon, Egypt, Libya, Tunisia, Algeria, Morocco, Palestine National Authority, Mauretania and Turkey. The resource data will be derived from Earth Observation satellite data, based on published and transparent methodologies and the data will be validated with existing ground measurements in the region. The database will be provided by SOLEMI and Helioclim-3 (SoDa) sources - Global Horizontal Irradiation (GHI) and Direct Normal Irradiation (DNI). The data will be made available via a distributed information system which will ensure the ease of access to the data. The free access to the data will include historical, annual and monthly averages, and more detailed data products and services will remain the domain of commercial data providers. This paper will show the first prototype of the user interface for an easy web access to the solar radiation as well as ancillary geographical data. With the presentation of this paper we aim to encourage potential users to give us feedback on the further development

Electrocardiographic Identification of Abnormal Ventricular Depolarization and Repolarization in Patients With Idiopathic Ventricular Fibrillation 11This study was supported by Grant 93.080 from The Netherlands Heart Foundation.22All editorial decisions for this article, including selection of referees, were made by a Guest Editor. This policy applies to all articles with authors from the University of California San Francisco.

AbstractObjectives. We sought to gain more insight into the arrhythmogenic etiology of idiopathic ventricular fibrillation (VF) by assessing ventricular depolarization and repolarization properties by means of various electrocardiographic (ECG) techniques.Background. Idiopathic VF occurs in the absence of demonstrable structural heart disease. Abnormalities in ventricular depolarization or repolarization have been related to increased vulnerability to VF in various cardiac disorders and are possibly also present in patients with idiopathic VF.Methods. In 17 patients with a first episode of idiopathic VF, 62-lead body surface QRST integral maps, QT dispersion on the 12-lead ECG and XYZ-lead signal-averaged ECGs were computed.Results. All subjects of a healthy control group had a normal dipolar QRST integral map. In patients with idiopathic VF, either a normal dipolar map (29%), a dipolar map with an abnormally large negative area on the right side of the thorax (24%) or a nondipolar map (47%) were recorded. Only four patients (24%) had increased QT dispersion on the 12-lead ECG and late potentials could be recorded in 6 (38%) of 16 patients. During a median follow-up duration of 56 months (range 9 to 136), a recurrent arrhythmic event occurred in 7 patients (41%), all of whom had an abnormal QRST integral map. Five of these patients had late potentials, and three showed increased QT dispersion on the 12-lead ECG.Conclusions. In patients with idiopathic VF, ventricular areas of slow conduction, regionally delayed repolarization or dispersion in repolarization can be identified. Therefore, various electrophysiologic conditions, alone or in combination, may be responsible for the occurrence of idiopathic VF. Body surface QRST integral mapping may be a promising method to identify those patients who do not show a recurrent episode of VF