746 research outputs found
Approche socio-anthropologique pour lâĂ©valuation de la vulnĂ©rabilitĂ© sociale des zones protĂ©gĂ©es par les digues fluviales du RhĂŽne aval
National audienceCette communication prĂ©sente un modĂšle dâĂ©valuation de la vulnĂ©rabilitĂ© sociale au risque inondation dans les zones protĂ©gĂ©es par des digues. Ce modĂšle articule trois Ă©chelles dâanalyse. Une Ă©chelle macrosociologique porte sur les tendances Ă©conomiques et socio-dĂ©mographiques afin dâĂ©valuer la vulnĂ©rabilitĂ© de grandes unitĂ©s territoriales cohĂ©rentes. LâĂ©chelle mĂ©soscopique fait rĂ©fĂ©rence Ă lâespace de groupes sociaux et de regroupements humains cohĂ©rents. Ă cette Ă©chelle, on privilĂ©gie le recours Ă lâenquĂȘte par questionnaires auprĂšs de mĂ©nages en zone inondable. La mĂ©thodologie proposĂ©e sâoriente en particulier vers une approche comportementaliste afin dâĂ©valuer la propension des individus Ă sâexposer au risque, en fonction Ă©galement de leurs capacitĂ©s dâadaptation, de leurs connaissances de lâinondation, des actions prĂ©ventives adoptĂ©es par les mĂ©nages, etc. Enfin, Ă lâĂ©chelle microsociologique, au moyen dâentretiens semi-directifs, lâapproche dĂ©veloppĂ©e tente de cerner les conditions et restrictions Ă la mise en Âœuvre de mĂ©thodes quantitatives pour lâĂ©valuation de la vulnĂ©rabilitĂ© sociale. / A three-scaled model is assumed to estimate the social vulnerability of leveed areas. A macro scale refers to the economic and socio-demographic trends that allow to assess the vulnerability of coherent large urban areas. A meso scale refers to homogeneous communities or social groups. At this scale, the assessment of vulnerability proceeds by questionnaire surveys of households in flood risk areas. The methodology especially adopts a behavioural approach trying to estimate the propensity of people to self-exposure to risks, risk-taking practices, adaptive capacities, knowledge of flood process, the mitigation actions undertaken by householders, etc. At a micro scale, thanks to semi-structured interviews the methodology tries to assess the conditions and the restrictions to an assessment of vulnerability by means of quantitative methods
The singular continuous diffraction measure of the Thue-Morse chain
The paradigm for singular continuous spectra in symbolic dynamics and in
mathematical diffraction is provided by the Thue-Morse chain, in its
realisation as a binary sequence with values in . We revisit this
example and derive a functional equation together with an explicit form of the
corresponding singular continuous diffraction measure, which is related to the
known representation as a Riesz product.Comment: 6 pages, 1 figure; revised and improved versio
Using the Hadamard and related transforms for simplifying the spectrum of the quantum baker's map
We rationalize the somewhat surprising efficacy of the Hadamard transform in
simplifying the eigenstates of the quantum baker's map, a paradigmatic model of
quantum chaos. This allows us to construct closely related, but new, transforms
that do significantly better, thus nearly solving for many states of the
quantum baker's map. These new transforms, which combine the standard Fourier
and Hadamard transforms in an interesting manner, are constructed from
eigenvectors of the shift permutation operator that are also simultaneous
eigenvectors of bit-flip (parity) and possess bit-reversal (time-reversal)
symmetry.Comment: Version to appear in J. Phys. A. Added discussions; modified title;
corrected minor error
Palindromic complexity of trees
We consider finite trees with edges labeled by letters on a finite alphabet
. Each pair of nodes defines a unique labeled path whose trace is a
word of the free monoid . The set of all such words defines the
language of the tree. In this paper, we investigate the palindromic complexity
of trees and provide hints for an upper bound on the number of distinct
palindromes in the language of a tree.Comment: Submitted to the conference DLT201
Quantum chaos in the spectrum of operators used in Shor's algorithm
We provide compelling evidence for the presence of quantum chaos in the
unitary part of Shor's factoring algorithm. In particular we analyze the
spectrum of this part after proper desymmetrization and show that the
fluctuations of the eigenangles as well as the distribution of the eigenvector
components follow the CUE ensemble of random matrices, of relevance to
quantized chaotic systems that violate time-reversal symmetry. However, as the
algorithm tracks the evolution of a single state, it is possible to employ
other operators, in particular it is possible that the generic quantum chaos
found above becomes of a nongeneric kind such as is found in the quantum cat
maps, and in toy models of the quantum bakers map.Comment: Title and paper modified to include interesting additional
possibilities. Principal results unaffected. Accepted for publication in
Phys. Rev. E as Rapid Com
IRMPD spectroscopy sheds new (InfraRed) light on the sulfate pattern of carbohydrates
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Time-to-birth prediction models and the influence of expert opinions
Preterm birth is the leading cause of death among children under five years old. The pathophysiology and etiology of preterm labor are not yet fully understood. This causes a large number of unnecessary hospitalizations due to high--sensitivity clinical policies, which has a significant psychological and economic impact. In this study, we present a predictive model, based on a new dataset containing information of 1,243 admissions, that predicts whether a patient will give birth within a given time after admission. Such a model could provide support in the clinical decision-making process. Predictions for birth within 48 h or 7 days after admission yield an Area Under the Curve of the Receiver Operating Characteristic (AUC) of 0.72 for both tasks. Furthermore, we show that by incorporating predictions made by experts at admission, which introduces a potential bias, the prediction effectiveness increases to an AUC score of 0.83 and 0.81 for these respective tasks
A Carbon Nanofilament-Bead Necklace
Carbon nanofilaments with carbon beads grown on their surfaces were successfully synthesized reproducibly by a floating catalyst CVD method. The nanofilaments hosting the pearl-like structures typically show an average diameter of about 60 nm, which mostly consists of low-ordered graphite layers. The beads with diameter range 150â450 nm are composed of hundreds of crumpled and random graphite layers. The mechanism for the formation of these beaded nanofilaments is ascribed to two nucleation processes of the pyrolytic carbon deposition, arising from a temperature gradient between different parts of the reaction chamber. Furthermore, the Raman scattering properties of the beaded nanofilaments have been measured, as well as their confocal Raman G-line images. The Raman spectra reveal that that the trunks of the nanofilaments have better graphitic properties than the beads, which is consistent with the HRTEM analysis. The beaded nanofilaments are expected to have high potential applications in composites, which should exhibit both particle- and fiber-reinforcing functions for the host matrixes
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