References of "Nicolay, Samuel"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 20 of 52 1 2 3     Analysis of PSII antenna size heterogeneity of Chlamydomonas reinhardtii during state transitionsde Marchin, Thomas ; Ghysels, Bart ; Nicolay, Samuel et alin Biochimica et Biophysica Acta-Bioenergetics (2014), 1837(1), 121-130PSII antenna size heterogeneity has been intensively studied in the past. Based on DCMU fluorescence rise kinetics, multiple types of photosystems with different properties were described. However, due to ... [more ▼]PSII antenna size heterogeneity has been intensively studied in the past. Based on DCMU fluorescence rise kinetics, multiple types of photosystems with different properties were described. However, due to the complexity of fluorescence signal analysis, multiple questions remain unanswered. The number of different types of PSII is still debated as well as their degree of connectivity. In Chlamydomonas reinhardtii we found that PSIIα possesses a high degree of connectivity and an antenna 2-3 times larger than PSIIβ, as described previously. We also found some connectivity for PSIIβ in contrast with the majority of previous studies. This is in agreement with biochemical studies which describe PSII mega-, super- and core- complexes in Chlamydomonas. In these studies, the smallest unit of PSII in vivo would be a dimer of two core complexes hence allowing connectivity. We discuss the possible relationships between PSIIα and PSIIβ and the PSII mega-, super- and core- complexes. We also showed that strain and medium dependent variations in the half-time of the fluorescence rise can be explained by variations in the proportions of PSIIα and PSIIβ. When analyzing the state transition process in vivo, we found that this process induces an inter-conversion of PSIIα and PSIIβ. During a transition from state 2 to state 1, DCMU fluorescence rise kinetics are satisfactorily fitted by considering two PSII populations with constant kinetic parameters. We discuss our findings about PSII heterogeneity during state transitions in relation with recent results on the remodeling of the pigment-protein PSII architecture during this process. [less ▲]Detailed reference viewed: 30 (12 ULg) On generalized Hölder-Zygmund spacesKreit, Damien ; Nicolay, Samuel Poster (2013, October 29)The Hölder spaces provide a natural way for measuring the smoothness of a function. These spaces appear in different areas such as approximation theory and multifractal analysis. The purpose of this ... [more ▼]The Hölder spaces provide a natural way for measuring the smoothness of a function. These spaces appear in different areas such as approximation theory and multifractal analysis. The purpose of this poster is to present a generalization of such spaces as well as some recent results about their characterizations. These spaces are a particular case of a generalization of Besov Spaces who have recently been extensively studied. [less ▲]Detailed reference viewed: 17 (2 ULg) Analysis of PSII antenna size heterogeneity of Chlamydomonas reinhardtii during state transitions - Colloque annuel de la Société Française de Photosynthèsede Marchin, Thomas ; Ghysels, Bart ; Nicolay, Samuel et alConference (2013, June 18)PSII antenna size heterogeneity has been extensively studied in the past. Based on in vivo DCMU fluorescence rise kinetics, at least two types of photosystems were described. They differ by their apparent ... [more ▼]PSII antenna size heterogeneity has been extensively studied in the past. Based on in vivo DCMU fluorescence rise kinetics, at least two types of photosystems were described. They differ by their apparent antenna size and connectivity (this last term refers to the transfer of absorbed energy from a closed PSII unit to an open neighboring unit). In this study, we analysed PSII heterogeneity in Chlamydomonas reinhardtii using non-linear linear regression fitting on in vivo DCMU fluorescence rise kinetics, with a focus on changes in PSII heterogeneity associated with state transitions. We found that PSIIα possesses a high degree of connectivity and an antenna about 3 times larger than PSIIβ, as described previously. In contrast with most earlier studies, we found some connectivity for PSIIβ (although it was highly variable). This is in agreement with recent models based on biochemical and structural analysis of PSII after gel filtration separation which describe PSII mega-, super- and core- complexes in Chlamydomonas. According to these studies, the smallest unit of PSII in vivo would be a dimer of two core complexes hence still allowing connectivity. We also showed that strain and medium dependent variations in the half-time of the fluorescence rise, generally taken as an indicator of the average cross-section of PSII, can be explained by variations in the proportions of PSIIα and PSIIβ. When analyzing the state transition process, we showed for the first time in vivo that it induces an inter-conversion of PSIIα and PSIIβ. These findings are discussed with respect to the latest insights on the remodeling of the pigment-protein PSII architecture during this process. [less ▲]Detailed reference viewed: 59 (18 ULg) An adaptation of $S^{\nu}$ spacesSimons, Laurent ; Bastin, Françoise ; Nicolay, Samuel Scientific conference (2013, May 31)The $S^\nu$ spaces have been introduced in 2004 by S. Jaffard in the context of multifractal analysis. In comparison with Besov spaces (the classical functional setting to study signals), these spaces of ... [more ▼]The $S^\nu$ spaces have been introduced in 2004 by S. Jaffard in the context of multifractal analysis. In comparison with Besov spaces (the classical functional setting to study signals), these spaces of functions related to the distribution of wavelet coefficients allow to obtain more information on the Hölder regularity of a signal. From a point of view of functional analysis, the $S^nu$ spaces can be considered as sequence spaces (because they are robust). Some properties (topology, complete metric, $p$-locally convexity,...) have been studied. The purpose of the talk is to present the beginning of an adaptation of the $S^nu$ spaces when the discrete wavelet coefficients are replaced by continuous wavelet transform coefficients. [less ▲]Detailed reference viewed: 17 (5 ULg) Régularité de la fonction de CantorSimons, Laurent ; Nicolay, Samuel Scientific conference (2013, January 28)La fonction de Cantor, bijection entre $[0,1]$ et $[0,1]^2$, est définie via les fractions continues. Par conséquent, il est assez difficile d'avoir une quelconque intuition sur son comportement. Le but ... [more ▼]La fonction de Cantor, bijection entre $[0,1]$ et $[0,1]^2$, est définie via les fractions continues. Par conséquent, il est assez difficile d'avoir une quelconque intuition sur son comportement. Le but de cet exposé est de présenter cette fonction particulière ainsi que sa régularité (continuité et régularité höldérienne). [less ▲]Detailed reference viewed: 14 (4 ULg) Characterizations of the elements of generalized Hölder-Zygmund spaces by means of their representationKreit, Damien ; Nicolay, Samuel in Journal of Approximation Theory (2013), 172We give three characterizations of the elements of generalized Hölder-Zygmund spaces. The first one, based on the Littlewood-Paley decomposition is already known, but the proof given here is much simpler ... [more ▼]We give three characterizations of the elements of generalized Hölder-Zygmund spaces. The first one, based on the Littlewood-Paley decomposition is already known, but the proof given here is much simpler. The second one, based on the wavelet decompositions generalizes a result obtained by Jaffard and Meyer. The third one uses generalized interpolation spaces. These results naturally extend the ones holding for the classical Hölder-Zygmund spaces. The manuscript has been accepted for publication in Journal of Approximation Theory. [less ▲]Detailed reference viewed: 40 (2 ULg) Several years El Niño forecast using a wavelet-based mode decompositionNicolay, Samuel ; Fettweis, Xavier Conference (2012, September 10)Detailed reference viewed: 22 (7 ULg) About Generic Properties of "Nowhere Analyticity"Bastin, Françoise ; Nicolay, Samuel ; Esser, Céline Conference (2012, May 08)A infinitely differentiable function f is is analytic at a point x if its Taylor series at this point converges to f on an open neighbourhood of x; if this is not the case, f has a singularity at x. A ... [more ▼]A infinitely differentiable function f is is analytic at a point x if its Taylor series at this point converges to f on an open neighbourhood of x; if this is not the case, f has a singularity at x. A function with a singularity at each point of the interval is called nowhere analytic on the interval. In this talk, we show that the set of nowhere analytic functions is prevalent in the Frechet space C([0;1]). We get then a deeper result using Gevrey classes. [less ▲]Detailed reference viewed: 33 (19 ULg) About the Regularity of Cantor's BijectionSimons, Laurent ; Nicolay, Samuel Conference (2012, May 07)Multifractal analysis has been introduced in the context of turbulence. Some tools have been developed to study the solutions of some PDEs. In this talk, we will examine the regularity of Cantor's ... [more ▼]Multifractal analysis has been introduced in the context of turbulence. Some tools have been developed to study the solutions of some PDEs. In this talk, we will examine the regularity of Cantor's bijection between the irrational numbers of the unit interval [0,1] and the irrational numbers of the unit square [0,1]^2. We will particularly show that its H older exponent is equal to 1/2 almost everywhere (with respect to the Lebesgue measure). [less ▲]Detailed reference viewed: 15 (4 ULg) Several years El Niño forecast using a wavelet-based mode decompositionNicolay, Samuel ; Fettweis, Xavier Conference (2012, April 23)Detailed reference viewed: 9 (3 ULg) Découverte d’un nouveau cycle du climatMabille, Georges ; Nicolay, Samuel Article for general public (2012)L'outil mathématique "transformée en ondelettes" est appliqué ici à des séries de températures de l'air au sol et met en évidence un cycle de l'ordre de 30 mois. Ce cycle s’observe sur une part importante ... [more ▼]L'outil mathématique "transformée en ondelettes" est appliqué ici à des séries de températures de l'air au sol et met en évidence un cycle de l'ordre de 30 mois. Ce cycle s’observe sur une part importante de la surface de la planète. [less ▲]Detailed reference viewed: 40 (4 ULg) Prevalence of ''nowhere analyticity''Bastin, Françoise ; Esser, Céline ; Nicolay, Samuel in Studia Mathematica (2012), 210(3), This note brings a complement to the study of genericity of functions which are nowhere analytic mainly in a measure-theoretic sense. We extend this study in Gevrey classes of functions.Detailed reference viewed: 31 (11 ULg) Some characterizations of generalized Hölder spacesKreit, Damien ; Nicolay, Samuel in Mathematische Nachrichten (2012), 285(17-18), 2157-2172Nous démontrons dans ce papier que les propriétés classiques des espaces de Hölder sont conservées pour les espaces de Hölder généralisés en terme de suite admissible. Nous donnons en particulier des ... [more ▼]Nous démontrons dans ce papier que les propriétés classiques des espaces de Hölder sont conservées pour les espaces de Hölder généralisés en terme de suite admissible. Nous donnons en particulier des définitions équivalentes de ces espaces ainsi que des conditions d'emboitement de tels espaces. [less ▲]Detailed reference viewed: 92 (10 ULg) A Wavelet Characterization for the Upper Global Hölder IndexClausel, Marianne; Nicolay, Samuel in Journal of Fourier Analysis and Applications (2012), 18(4), 750-769The upper Hölder index has been introduced to describe smoothness properties of a continuous function. It can be seen as the irregular counterpart of the usual Hölder index and has been used to ... [more ▼]The upper Hölder index has been introduced to describe smoothness properties of a continuous function. It can be seen as the irregular counterpart of the usual Hölder index and has been used to investigate the behavior at the origin of the modulus of smoothness in many classical cases. In this paper, we prove a characterization of the upper Hölder index in terms of wavelet coefficients. This result is a first step in the estimation of this exponent using wavelet methods. [less ▲]Detailed reference viewed: 7 (3 ULg) Étude fréquentielle de données via la transformée en ondelette : application aux cycles climatiquesMabille, Georges ; Fettweis, Xavier ; Erpicum, Michel et alin Bulletin de la Société Géographique de Liège (2012), 58Understanding the climate requires a complex study of time series connected to weather parameters. The climatologist frequently applies signal processing tools and often uses the harmonic analysis and the ... [more ▼]Understanding the climate requires a complex study of time series connected to weather parameters. The climatologist frequently applies signal processing tools and often uses the harmonic analysis and the Fourier transform. This article is dedicated to the description of a new tool, elaborated by mathematicians, which completes the outfit of intruments intended for signal analysis. The scale spectrum, which synthetizes a part of the information supplied by the wavelet transform, possesses the property to reveal pseudo-cycles which evolves around an average period. When applied to air surface temperature time series obtained from more than one hundred weather stations, to reanalysis data and to climatic indices which characterize the tropospheric flows, the wavelet transforms and the scale spectra reveal cycles with periods close to 30 months and 42 months. The Solar parameters analysis also leads to the existence of pseudo-cycles with frequencies corresponding to those found in the temperature time series and climatic indices. [less ▲]Detailed reference viewed: 46 (2 ULg) Estimation of the Sea Level Rise by 2100 Resulting from Changes in the Surface Mass Balance of the Greenland Ice SheetFettweis, Xavier ; Belleflamme, Alexandre ; Erpicum, Michel et alin Blanco, Juan; Kheradmand, Houshang (Eds.) Climate Change - Geophysical Foundations and Ecological Effects (2011)We present here future projections of the Greenland climate performed by the regional climate model MAR coupled with a snow model and forced by two scenarios of greenhouse gas emissions from the global ... [more ▼]We present here future projections of the Greenland climate performed by the regional climate model MAR coupled with a snow model and forced by two scenarios of greenhouse gas emissions from the global model CanESM2 of the next IPCC assessment report (AR5). Knowing that MAR forced by CanESM2 over the current climate (1970-1999) compares well with the reference MAR simulation performed by using the ERA-40 reanalysis as forcing, this gives us confidence in our future projections. For the RCP4.5 scenario (optimistic) and respectively RCP8.5 scenario (pessimistic), MAR projects a sea level rise in 2100 of 6.5 +/- 1.5 cm and respectively 14+/-2 cm as result of increasing surface melt of the Greenland ice sheet over 2000-2100. It is true that MAR projects a small increase of snowfall in the winter because the atmosphere will be warmer and therefore can contain more water vapor. But this is not sufficient to offset the acceleration of melt, notably for the scenario RCP8.5 which projects an increase of 10 °C in 2100 above the ice sheet. This work ﬁts in the ICE2SEA project (http://www.ice2sea.eu) of the 7th Framework Program (FP7) which aims to improve the projections of the continental ice melting contribution to sea level rise. [less ▲]Detailed reference viewed: 212 (19 ULg) On generalized Hölder spacesKreit, Damien ; Nicolay, Samuel Poster (2011, June)The Hölder spaces provide a natural way for measuring the smoothness of a function. These spaces appear in different areas such as approximation theory and multifractal analysis and lead to natural ... [more ▼]The Hölder spaces provide a natural way for measuring the smoothness of a function. These spaces appear in different areas such as approximation theory and multifractal analysis and lead to natural definitions of the notion of fractal function; for example a function belonging to $C^\alpha$ with $\alpha\in (0,1)$ typically has a fractal graph. The purpose of this poster is to present a generalization of such spaces as well as some recent results about their characterizations. [less ▲]Detailed reference viewed: 93 (15 ULg) A wavelet-based mode decompositionNicolay, Samuel in European Physical Journal B -- Condensed Matter (2011), 80We propose a wavelet-based method for analyzing non-stationary data. The idea, inspired by the empirical mode decomposition, is to decompose a data set into a ﬁnite number of components, well separated in ... [more ▼]We propose a wavelet-based method for analyzing non-stationary data. The idea, inspired by the empirical mode decomposition, is to decompose a data set into a ﬁnite number of components, well separated in the time-frequency plane, plus a residue, such that each component has a zero mean and is associated to one frequency only. When applied to climatic data, this method gives interesting results. [less ▲]Detailed reference viewed: 46 (15 ULg) Present and future climates of the Greenland ice sheet according to the IPCC AR4 modelsFranco, Bruno ; Fettweis, Xavier ; Erpicum, Michel et alin Climate Dynamics (2011), 36The atmosphere–ocean general circulation models (AOGCMs) used for the IPCC 4th Assessment Report (IPCC AR4) are evaluated for the Greenland ice sheet (GrIS) current climate modelling. The most suited ... [more ▼]The atmosphere–ocean general circulation models (AOGCMs) used for the IPCC 4th Assessment Report (IPCC AR4) are evaluated for the Greenland ice sheet (GrIS) current climate modelling. The most suited AOGCMs for Greenland climate simulation are then selected on the basis of comparison between the 1970–1999 outputs of the Climate of the twentieth Century experiment (20C3M) and reanalyses (ECMWF, NCEP/NCAR). This comparison indicates that the representation quality of surface parameters such as temperature and precipitation are highly correlated to the atmospheric circulation (500 hPa geopotential height) and its interannual variability (North Atlantic oscillation). The outputs of the three most suitable AOGCMs for present-day climate simulation are then used to assess the changes estimated by three IPCC greenhouse gas emissions scenarios (SRES) over the GrIS for the 2070–2099 period. Future atmospheric circulation changes are projected to dampen the zonal flow, enhance the meridional fluxes and therefore provide additional heat and moisture to the GrIS, increasing temperature over the whole ice sheet and precipitation over its northeastern area. We also show that the GrIS surface mass balance anomalies from the SRES A1B scenario amount to −300 km3/year with respect to the 1970–1999 period, leading to a global sea-level rise of 5 cm by the end of the 21st century. This work can help to select the boundaries conditions for AOGCMs-based downscaled future projections. [less ▲]Detailed reference viewed: 109 (33 ULg) The 1958–2009 Greenland ice sheet surface melt and the mid-tropospheric atmospheric circulationFettweis, Xavier ; Mabille, Georges; Erpicum, Michel et alin Climate Dynamics (2011), 36(1 (2011)), 139-159In order to assess the impact of the mid-tropospheric circulation over the Greenland ice sheet (GrIS) on surface melt, as simulated by the regional climate model MAR, an automatic Circulation type ... [more ▼]In order to assess the impact of the mid-tropospheric circulation over the Greenland ice sheet (GrIS) on surface melt, as simulated by the regional climate model MAR, an automatic Circulation type classification (CTC) based on 500 hPa geopotential height from reanalyses is developed. General circulation correlates significantly with the surface melt anomalies for the summers in the period 1958–2009. The record surface melt events observed during the summers of 2007–2009 are linked to the exceptional persistence of atmospheric circulations favouring warm air advection. The CTC emphasizes that summer 500 hPa circulation patterns have changed since the beginning of the 2000s; this process is partly responsible for the recent warming observed over the GrIS. [less ▲]Detailed reference viewed: 103 (34 ULg) 1 2 3