Christophe Letellier

Prof. Christophe Letellier

orcid

Research Focus & Metrics

Academic Career Length

33Years (1994-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 January 2019 in JAMA
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Journal Article
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FDFabrice Denis
Fabrice Denis
EBEthan Basch
Ethan Basch
ASAnne-Lise Septans
Anne-Lise Septans
JBJaafar Bennouna
Jaafar Bennouna
TUThierry Urban
Thierry Urban
CLChristophe Letellier
Christophe Letellier
This study reports 2-year survival outcomes among patients with advanced nonprogressive stage IIA to IV lung cancer randomized to symptom monitoring during chem

10 April 2017 in JNCI: Journal of the National Cancer Institute
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FDFabrice Denis
Fabrice Denis
CLClaire Lethrosne
Claire Lethrosne
NPNicolas Pourel
Nicolas Pourel
OMOlivier Molinier
Olivier Molinier
YPYoann Pointreau
Yoann Pointreau
CLChristophe Letellier
Christophe Letellier
The use of web-based monitoring for lung cancer patients is growing in interest because of promising recent results suggesting improvement in cancer and resource utilization outcomes. It remains an open question whether the overall survival (OS) in these patients could be improved by using a web-mediated follow-up rather than classical scheduled follow-up and imaging. Advanced-stage lung cancer patients without evidence of disease progression after or during initial treatment were randomly assigned in a multicenter phase III trial to compare a web-mediated follow-up algorithm (experimental arm), based on weekly self-scored patient symptoms, with routine follow-up with CT scans scheduled every three to six months according to the disease stage (control arm). In the experimental arm, an alert email was automatically sent to the oncologist when self-scored symptoms matched predefined criteria. The primary outcome was OS. From June 2014 to January 2016, 133 patients were enrolled and 121 were retained in the intent-to-treat analysis; 12 deemed ineligible after random assignment were not subsequently followed. Most of the patients (95.1%) had stage III or IV disease. The median follow-up was nine months. The median OS was 19.0 months (95% confidence interval [CI] = 12.5 to noncalculable) in the experimental and 12.0 months (95% CI = 8.6 to 16.4) in the control arm (one-sided P = .001) (hazard ratio = 0.32, 95% CI = 0.15 to 0.67, one-sided P = .002). The performance status at first detected relapse was 0 to 1 for 75.9% of the patients in the experimental arm and for 32.5% of those in the control arm (two-sided P < .001). Optimal treatment was initiated in 72.4% of the patients in the experimental arm and in 32.5% of those in the control arm (two-sided P < .001). A web-mediated follow-up algorithm based on self-reported symptoms improved OS due to early relapse detection and better performance status at relapse.

1 March 1995 in Chaos: An Interdisciplinary Journal of Nonlinear Science
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Journal Article
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CLChristophe Letellier
Christophe Letellier
PDP. Dutertre
P. Dutertre
BMB. Maheu
B. Maheu
The Rössler system has been exhaustively studied for parameter values (a∈[0.33,0.557],b=2,c=4). Periodic orbits have been systematically extracted from Poincaré maps and the following problems have been addressed: (i) all low order periodic orbits are extracted, (ii) encoding of periodic orbits by symbolic dynamics (from 2 letters up to 11 letters) is achieved, (iii) some rules of growth and of pruning of the periodic orbits population are obtained, and (iv) the templates of the attractors are elaborated to characterize the attractors topology.

1 June 1994 in Physical Review E
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GGG. Gouesbet
G. Gouesbet
CLChristophe Letellier
Christophe Letellier
A multivariate polynomial L2 approximation on nets is designed for global vector-field reconstructions of time continuous dynamical systems. The technique is tested by investigating standard forms of the Rössler band, the Lorenz mask, and a chaotic attractor produced by a simple model of thermal lens oscillations.

1 January 2009 in Mathematical Problems in Engineering
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LALuis A. Aguirre
Luis A. Aguirre
CLChristophe Letellier
Christophe Letellier
This paper reviews the major developments of modeling techniques applied to nonlinear dynamics and chaos. Model representations, parameter estimation techniques, data requirements, and model validation are some of the key topics that are covered in this paper, which surveys slightly over two decades since the pioneering papers on the subject appeared in the literature.

30 April 2012 in Chaos: An Interdisciplinary Journal of Nonlinear Science
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Journal Article
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JGJean-Marc Ginoux
Jean-Marc Ginoux
CLChristophe Letellier
Christophe Letellier
Relaxation oscillations are commonly associated with the name of Balthazar van der Pol via his paper (Philosophical Magazine, 1926) in which he apparently introduced this terminology to describe the nonlinear oscillations produced by self-sustained oscillating systems such as a triode circuit. Our aim is to investigate how relaxation oscillations were actually discovered. Browsing the literature from the late 19th century, we identified four self-oscillating systems in which relaxation oscillations have been observed: (i) the series dynamo machine conducted by Gérard-Lescuyer (1880), (ii) the musical arc discovered by Duddell (1901) and investigated by Blondel (1905), (iii) the triode invented by de Forest (1907), and (iv) the multivibrator elaborated by Abraham and Bloch (1917). The differential equation describing such a self-oscillating system was proposed by Poincaré for the musical arc (1908), by Janet for the series dynamo machine (1919), and by Blondel for the triode (1919). Once Janet (1919) established that these three self-oscillating systems can be described by the same equation, van der Pol proposed (1926) a generic dimensionless equation which captures the relevant dynamical properties shared by these systems. Van der Pol’s contributions during the period of 1926-1930 were investigated to show how, with Le Corbeiller’s help, he popularized the “relaxation oscillations” using the previous experiments as examples and, turned them into a concept.