Asturies et Castilles

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201

Analysis of a fractal boundary: the graph of the Knopp function

A usual classification tool to study a fractal interface is the computation of its fractal dimension. But a recent method developed by Y. Heurteaux and S. Jaffard proposes to compute either weak and strong accessibility exponents or local Lp regularity exponents (the so-called p-exponent). These exponents describe locally the behavior of the interface. We apply this method to the graph of the Knopp function. The Knopp function itself has everywhere the same p-exponent. Nevertheless, using the characterization of the maxima and minima done by B. Dubuc and S. Dubuc, we will compute the p-exponent of the characteristic function of domain under the graph of F at each point (x,F(x)) and show that p-exponents, weak and strong accessibility exponents change from point to point. Furthermore we will derive a characterization of the local extrema of the function according to the values of these exponents

CRDB: a database of charged cosmic rays

This paper gives a description of a new on-line database http://lpsc.in2p3.fr/crdb and associated on-line tools (data selection, data export, plots, etc.) for charged cosmic-ray measurements. The experimental setups (type, flight dates, techniques) from which the data originate are included in the database, along with the references to all relevant publications. The database relies on the MySQL5 engine. The web pages and queries are based on PHP, AJAX and the jquery, jquery.cluetip, jquery-ui, and table-sorter third-party libraries. In this first release, we restrict ourselves to Galactic cosmic rays with Z<=30 and a kinetic energy per nucleon up to a few tens of TeV/n. This corresponds to more than 200 different sub-experiments (i.e., different experiments, or data from the same experiment flying at different times) in as many publications. We set up a cosmic-ray database and provide tools to sort and visualise the data. New data can be submitted, providing the community with a collaborative tool to archive past and future cosmic-ray measurements. Any help/ideas to further expand and/or complement the database is welcome (please contact [email protected]).Comment: 13 pages, 6 figures: new Sect. 2.3 on Solar modulation parameters in CRDB v2.1, see http://lpsc.in2p3.fr/crd

Democracy Versus the National Security State

The Single Chip Cloud computer (SCC) is an experimental processor from Intel Labs with 48 cores connected with a 2D mesh on-chip network. We evaluate the performance of SCC regarding off-chip memory accesses and communication capabilities. As benchmark, we use the merging phase of mergesort, a representative of a memory access intensive algorithm. Mergesort is parallelized and adapted in 4 variants, each leveraging different features of the SCC, in order to assess and compare their performance impact. Our results motivate to consider on-chip pipelined mergesort on SCC, which is an issue of ongoing work

Random Forests and Networks Analysis

D. Wilson~\cite{[Wi]} in the 1990's described a simple and efficient algorithm based on loop-erased random walks to sample uniform spanning trees and more generally weighted trees or forests spanning a given graph. This algorithm provides a powerful tool in analyzing structures on networks and along this line of thinking, in recent works~\cite{AG1,AG2,ACGM1,ACGM2} we focused on applications of spanning rooted forests on finite graphs. The resulting main conclusions are reviewed in this paper by collecting related theorems, algorithms, heuristics and numerical experiments. A first foundational part on determinantal structures and efficient sampling procedures is followed by four main applications: 1) a random-walk-based notion of well-distributed points in a graph 2) how to describe metastable dynamics in finite settings by means of Markov intertwining dualities 3) coarse graining schemes for networks and associated processes 4) wavelets-like pyramidal algorithms for graph signals.Comment: Survey pape

Projecte per a una gran biblioteca pública: la biblioteca, lloc de democràcia

Conferència pronunciada el 15 de novembre de 1989 a la seu del Col·legi de Periodistes, a Barcelona. L'autor descriu tres aspectes que caracteritzen la biblioteca pública: com a lloc d'identitat col·lectiva, com a lloc de formació i d'informació, i com a lloc de paraula, que configuren la biblioteca com a lloc de democràcia

Asymmetric palladium (0)-catalyzed C(sp³)-H arylation and natural product synthesis

Over the last decades, C(sp3)-H activation has emerged as a powerful tool for building structural complexity in a step-economical manner. In this context, our group developed diverse methodologies and applied them to the synthesis of natural products, bioactive molecules and valuable building blocks. More recently, our group was attracted, as others, by the development of asymmetric versions of such reactions. In this regard, the synthesis of enantioenriched indanes through asymmetric palladium-catalyzed C(sp3)-H arylation was described using a chiral binepine ligand for chiral induction. This work motivated us to develop other asymmetric reactions and apply them to the synthesis of interesting compounds. In this optic, we first investigated the use of a chiral anion as an alternative to the classic approach using chiral NHC or phosphorylated ligands. This led to the development of a new methodology for the synthesis of enantioenriched indolines. We then elaborated a divergent asymmetric synthesis of three (nor)illudalanes sesquiterpenes using C(sp3)-H arylation as the key step, which demonstrates the potential of such transformations to access chiral natural products. Finally, we are actually developing a new methodology for the asymmetric C(sp3)-H arylation of unactivated methylene positions to prepare valuable indanes related to potential natural product targets

Conflicts over compensation of expropriation. The case of farmland in France.

From a legal sociology perspective, the research presented here aims to show that the legal claims strategies in matters of land expropriation cannot be satisfactorily explained without taking into account observable judicial practices at a local level. Indeed, the characteristics of real estate assets, both their private use and public management, are essential elements which explain why within the framework of public use projects, either negotiated settlement or, on the contrary, referral to court, is prescribed as the relevant context for determining compensation. This review of the current state of the law concerns two aspects which are different but both strongly nested in local land systems. First, we find the situation of individuals with regard to the rights they possess over real estate assets. Indeed, when we speak about land expropriation, it is above all in relation to the stakes behind owners' property rights. But the law also provides for the protection of the rights of non-owners, such as lease-holders endowed with land-use rights whose business interests may be adversely affected by land development projects. As discussed further in the paper, this situation is unavoidable when dealing with the expropriation of land supporting economic activity in which land leasing is a widespread practice, such as agriculture in France. In terms of public law, it is essential to take into account local judicial practices, not only to understand the structure of disputes between condemnor and condemnee, but also to explain the decision to go to court. Regulatory practices in matters of urban development projects clearly influence the nature of building permits associated with developed and undeveloped sites. The type of zoning, the building code for construction and extension of existing structures and building standards for public infrastructure projects (land reclamation, roadbuilding, electricity, water…) are all factors which directly influence land value estimates. It seems reasonable, then, to posit the idea that land disputes often directly reflect local urban building codes and, consequently, policies implemented by local authorities. We wish to further underline the fact that eminent domain is very often exercised within the context not of large infrastructure projects but of ordinary urban development. Recourse to ‘public use' prerogatives is thus used as a complement to urban planning policies