Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailNon-radial non-adiabatic solar like oscillations in red giants : Evolutionnary effects on theoretical power spectrum.
Grosjean, Mathieu ULg; Dupret, Marc-Antoine ULg

Scientific conference (2012)

Corot and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. The study of non-adiabatic and energetic aspects of these ... [more ▼]

Corot and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. The study of non-adiabatic and energetic aspects of these oscillations is of great importance to predict not only the frequencies but also the FWMH and Heights of the peaks in power spectrum. This two observables are indeed directly related to modes lifetimes, necessitating a non-adiabatic approach. The height also depends on the energy injected in the mode by the turbulence in the upper convective-zone. We use a stochastic excitation model to compute the amplitudes of each modes. We investigate the differences in power spectrum between an RGB and an HB stars with the same global parameters. We also follow the evolution of a star on the RGB and investigate the effect of its ascension on theoretical power spectrum to predict when on the RGB are mixed-modes more likely to be detectable. [less ▲]

Detailed reference viewed: 3 (0 ULg)
Full Text
Peer Reviewed
See detailNon-radial oscillations in the red giant HR 7349 measured by CoRoT
Carrier, F.; De Ridder, J.; Baudin, F. et al

in Astronomy and Astrophysics (2010), 509

Context. Convection in red giant stars excites resonant acoustic waves whose frequencies depend on the sound speed inside the star, which in turn depends on the properties of the stellar interior ... [more ▼]

Context. Convection in red giant stars excites resonant acoustic waves whose frequencies depend on the sound speed inside the star, which in turn depends on the properties of the stellar interior. Therefore, asteroseismology is the most robust available method for probing the internal structure of red giant stars. <BR /> Aims: Solar-like oscillations in the red giant HR 7349 are investigated. <BR /> Methods: Our study is based on a time series of 380 760 photometric measurements spread over 5 months obtained with the CoRoT satellite. Mode parameters were estimated using maximum likelihood estimation of the power spectrum. <BR /> Results: The power spectrum of the high-precision time series clearly exhibits several identifiable peaks between 19 and 40 μHz showing regularity with a mean large and small spacing of Πν = 3.47 ± 0.12 μHz and δν[SUB]02[/SUB] = 0.65 ± 0.10 μHz. Nineteen individual modes are identified with amplitudes in the range from 35 to 115 ppm. The mode damping time is estimated to be 14.7[SUP]+4.7[/SUP][SUB]-2.9[/SUB] days. The CoRoT space mission has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany and Spain. [less ▲]

Detailed reference viewed: 55 (30 ULg)
Full Text
See detailNon-radial, non-adiabatic solar-like oscillations in RGB and HB stars
Grosjean, Mathieu ULg; Dupret, Marc-Antoine ULg; Belkacem, K. et al

in EPJ Web of Conferences (2013, March 01), 43

CoRoT and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. We compare the theoretical spectrum of two red giants in ... [more ▼]

CoRoT and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. We compare the theoretical spectrum of two red giants in the same region of the HR diagram but in different evolutionary phases. We present here our first results on the inertia, lifetimes and amplitudes of the oscillations and discuss the differences between the two stars. [less ▲]

Detailed reference viewed: 18 (9 ULg)
Full Text
See detailNon-radial, non-adiabatic solar-like oscillations in RGB and HB stars
Grosjean, Mathieu ULg; Dupret, Marc-Antoine ULg; Belkacem, Kevin et al

Poster (2012, July)

Corot and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. We compare the theoretical spectrum (amplitudes and life ... [more ▼]

Corot and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. We compare the theoretical spectrum (amplitudes and life- times) of two red giants in the same region of the HR diagram but in different evolutionary phases. The lifetimes are obtained by computing theoretical non-adiabatic non-radial solar-like oscillations for mixed modes in the two models. Thanks to this, we have been able to compute the oscillation amplitudes through a stochastic excitation model. We present here our first results on the inertia, damping rates and amplitudes of the oscillations in the two stars and discuss the trapping, the visibilities and the am- plitudes of the different modes. The differences in the spectra of the two stars are also investigated. As already known, the period spacings in the two models are very different. Moreover, we find significant differences in amplitudes and lifetimes between the two models. [less ▲]

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
See detailNon-random genomic integration - an intrinsic property of retrogenes in Drosophila?
Metta, Muralidhar ULg; Schlotterer, C.

in BMC Evolutionary Biology (2010), 10(1), 114

ABSTRACT: BACKGROUND: The Drosophila X-chromosome shows a significant underrepresentation of genes with male-biased gene expression (demasculinization). This trend is matched by retrogenes, which ... [more ▼]

ABSTRACT: BACKGROUND: The Drosophila X-chromosome shows a significant underrepresentation of genes with male-biased gene expression (demasculinization). This trend is matched by retrogenes, which typically have a male biased gene expression pattern and show a significant movement bias from X-chromosomes to autosomes. It is currently assumed that these patterns are best explained by selection, either mediated by male meiotic sex chromosome inactivation (MSCI) or sexually antagonistic forces. We scrutinized the evolutionary dynamics of retroposition by focusing on retrogenes for which the parental copy has degenerated. RESULTS: Consistent with a functional substitution of the degenerated gene by the retrogene, patterns of sequence evolution and gene expression were similar between retroposed and parental genes. Like previous studies, our set of retrogenes showed a significant movement off the X-chromosome. In contrast to data sets where retroposition caused gene duplication, the genes in our study showed primarily female-biased or unbiased gene expression. CONCLUSIONS: Based on our results, the biased transposition pattern cannot be explained by MSCI and probably not by sexual antagonism. Rather, we propose that the movement away from the X-chromosome represents a general property of retroposition in Drosophila. [less ▲]

Detailed reference viewed: 10 (3 ULg)
Full Text
Peer Reviewed
See detailLes non-recommandations dans le traitement de l'arthrose et de la polyarthrite rhumatoïde, ou pourquoi la médecine basée sur le niveau de preuve ne s'applique pas (encore) à la rhumatologie
Malaise, Michel ULg

in Revue Médicale de Liège (2000), 55(5), 466-475

The speed with which the phrase "Evidence-Based Medicine" has entered our language has been astonishing. Virtually all medical areas are concerned, but it probably applies best when clearcut diagnosis can ... [more ▼]

The speed with which the phrase "Evidence-Based Medicine" has entered our language has been astonishing. Virtually all medical areas are concerned, but it probably applies best when clearcut diagnosis can be made or when mortality or well-defined morbidity are the outcomes, two conditions not really frequently encountered in rheumatology. We will discuss why rheumatology is probably not ready yet for the concept and will systematically review why "Evidence-Based Medicine" could in fact be "evidence-biased medicine". We will emphasize why evidence-based medicine can not replace the personal experience and knowledge of patients, two major corner-stones in the clinician's daily work, but should simply be an access to scientific data for the benefit of both patient and physician. [less ▲]

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailLa non-représentation d'enfants et les moyens de défense
Kefer, Fabienne ULg

in Annales de la Faculté de droit de l'Université de Liège (1988)

Detailed reference viewed: 38 (0 ULg)
Peer Reviewed
See detailNon-responsive generalised bacterial infection associated with systemic lupus erytematous in a beauceron
Clercx, Cécile ULg; Mc Entee, Katleen; Gilbert, Sophie et al

in Journal of Veterinary Internal Medicine (1997)

Detailed reference viewed: 5 (1 ULg)
Peer Reviewed
See detailNon-Rigid Object Tracker Based On a Robust Combination of Parametric Active Contour and Point Distribution Model
Olszewska, Joanna; Mathes, Tom; De Vleeschouwer, Christophe et al

in Proceedings of the SPIE Conference on Visual Communication and Image Processing (2007)

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailNon-small cell lung cancer and health-related quality of life (HRQOL): Is baseline HRQOL of prognostic value for survival?
Bottomley, A.; Smit, E.; Efficace, F. et al

in Quality of Life Research (2005), 14(9), 20501013

Detailed reference viewed: 9 (2 ULg)
Full Text
See detailNon-Standard economics and competition law
Sibony, Anne-Lise ULg

Conference (2009, November 26)

Detailed reference viewed: 32 (4 ULg)
Full Text
Peer Reviewed
See detailNon-starch polysaccharide-degrading enzymes alter the microbial community and the fermentation patterns of barley cultivars and wheat products in an in vitro model of the porcine gastrointestinal tract
Bindelle, Jérôme ULg; Pieper, Robert; Montoya, Carlos A. et al

in FEMS Microbiology Ecology (2011), 76

An in vitro experiment was carried out to assess how non-starch polysaccharide (NSP)-degrading enzymes influence fermentation of dietary fibre in the pig large intestine. Seven wheat and barley products ... [more ▼]

An in vitro experiment was carried out to assess how non-starch polysaccharide (NSP)-degrading enzymes influence fermentation of dietary fibre in the pig large intestine. Seven wheat and barley products and cultivars with differing carbohydrate fractions (CHO) were hydrolyzed using pepsin and pancreatin in the presence or not of NSP-degrading enzymes (xylanase and b-glucanase) and the filter retentate fermented with sow fecal bacteria. Dry matter, starch, crude protein and β-glucan digestibilities during hydrolysis were measured. Fermentation kinetics of the hydrolyzed ingredients were modelled. Short-chain fatty acids (SCFA) production and molar ratio were compared after 12, 24 and 72 h. Microbial communities were analyzed after 72 h of fermentation using terminal restriction fragment length polymorphism (TRFLP). The results showed an increase of nutrient digestibility (P<0.001), whereas fermentability and SCFA production decreased (P<0.001) with addition of the enzyme. SCFA and bacterial community profiles indicated also a shift from propionate to acetate and an increase in cellulolytic Ruminoccocus- and xylanolytic Clostridium-like bacteria. This is explained by the increase in slowly fermentable insoluble CHO and the lower proportion of rapidly fermentable β-glucan and starch in the retentate when grains were incubated with NSP-degrading enzymes. Shifts were also different for the 4 barley varieties investigated, showing that the efficiency of the enzymes depends on the structure of the CHO fractions in cereal products and cultivars. [less ▲]

Detailed reference viewed: 78 (37 ULg)
Peer Reviewed
See detailNon-stationnarite et aspects fonctionnels du comportement agonistique chez Tilapia macrochir (Boulenger 1912) (Piscer: Cichlidae)
Balthazart, Jacques ULg

in Acta Zoologica et Pathologica Antverpiensia (1974), 58(0), 29-40

Detailed reference viewed: 12 (3 ULg)
Full Text
Peer Reviewed
See detailNon-symbiotic hemoglobin-2 leads to an elevated energy state and to a combined increase in polyunsaturated fatty acids and total oil content when over-expressed in developing seeds of transgenic Arabidopsis plants.
Vigeolas, Hélène ULg; Huhn, D.; Geigenberger, P.

in Plant Physiology (2011)

Non-symbiotic hemoglobins are ubiquitously expressed in plants and divided into two different classes based on gene-expression pattern and oxygen binding-properties. Most of the published research has ... [more ▼]

Non-symbiotic hemoglobins are ubiquitously expressed in plants and divided into two different classes based on gene-expression pattern and oxygen binding-properties. Most of the published research has been on the function of class-1 hemoglobins. To investigate the role of class-2 hemoglobins, transgenic Arabidopsis plants were generated over-expressing Arabidopsis hemoglobin-2 (AHb2) under the control of a seed-specific promoter. Over-expression of AHb2 led to a 40% increase in the total fatty acid content of developing and mature seeds in three subsequent generations. This was mainly due to an increase in the poly-unsaturated C18:2 (omega-6) linoleic and C18:3 (omega-3) alpha-linolenic acids. Moreover, AHb2 over-expression led to an increase in the C18:2/C18:1 and C18:3/C18:2 ratios as well as in the C18:3 content in mol% of total fatty acids and in the unsaturation/saturation index of total seed lipids. The increase in fatty-acid content was mainly due to a stimulation of the rate of triacylglycerol synthesis which was attributable to a 3-fold higher energy state and a 2-fold higher sucrose content of the seeds. Under low external oxygen, AHb2 over-expression maintained an up to 5-fold higher energy state and prevented fermentation. This is consistent with AHb2 over-expression results in improved oxygen availability within developing seeds. In contrast to this, over-expression of class-1 hemoglobin did not lead to any significant increase in the metabolic performance of the seeds. Results provide evidence for a specific function of class-2 hemoglobin in seed oil production and in promoting the accumulation of poly-unsaturated fatty acids by facilitating oxygen supply in developing seeds. [less ▲]

Detailed reference viewed: 27 (6 ULg)
Full Text
Peer Reviewed
See detailNon-symmetrically substituted phenoxazinones from laccase-mediated oxidative cross-coupling of aminophenols: an experimental and theoretical insight
Bruyneel, Frédéric; Dive, Georges ULg; Marchand-Brynaert, Jacqueline

in Organic & Biomolecular Chemistry (2012), 10

Detailed reference viewed: 13 (4 ULg)
Full Text
Peer Reviewed
See detailNon-synoptic versus pseudo-synoptic data sets: an assimilation experiment
Rixen, Michel; Allen, J. T.; Beckers, Jean-Marie ULg

in Journal of Marine Systems (2001), 29(1-4), 313-333

Several first-order correction methods are implemented to compute pseudo-synoptic data sets from non-synoptic raw data sets. These include a geostrophic relocation method, a linear and a quadratic ... [more ▼]

Several first-order correction methods are implemented to compute pseudo-synoptic data sets from non-synoptic raw data sets. These include a geostrophic relocation method, a linear and a quadratic interpolation method, and a method using spatio-temporal correlation functions. The relocation method involves analyses and geostrophic velocity computations to allow the relocation of stations in time and space to a particular analysis time. Interpolation methods involve several almost identical and consecutive surveys interpolated in time. Temporal weighting methods are based upon a spatio-temporal function modifying the weight on data with respect to the time at which they have been sampled. These techniques are tested on the OMEGA data set and are validated by simple nudging assimilation into a 3D primitive equation model (PE). It is shown that, under certain hypothesis, these methods are able to correct the lack of synopticity in hydrographic data sets, and improve the diagnosis of vertical velocities computed from the Omega equation. These methods are of particular interest for the scientific community. They might be used together with diagnostic models. They might provide suitable pseudo-synoptic fields required by 3D PE models as initial conditions, boundary conditions or assimilation data sets. They may also be useful in the design of mesoscale samplings. (C) 2001 Elsevier Science B.V. All rights reserved. [less ▲]

Detailed reference viewed: 47 (2 ULg)
Full Text
See detailNon-thermal emission from early-type binaries
Rauw, Grégor ULg

in Cosmic Gamma-Ray Sources (2004)

Not Available

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailNon-thermal emission processes in massive binaries
De Becker, Michaël ULg

in Astronomy and Astrophysics Review (2007), 14(3-4), 171-216

In this paper, I present a general discussion of several astrophysical processes likely to play a role in the production of non-thermal emission in massive stars, with emphasis on massive binaries. Even ... [more ▼]

In this paper, I present a general discussion of several astrophysical processes likely to play a role in the production of non-thermal emission in massive stars, with emphasis on massive binaries. Even though the discussion will start in the radio domain where the non-thermal emission was first detected, the census of physical processes involved in the non-thermal emission from massive stars shows that many spectral domains are concerned, from the radio to the very high energies. First, the theoretical aspects of the non-thermal emission from early-type stars will be addressed. The main topics that will be discussed are respectively the physics of individual stellar winds and their interaction in binary systems, the acceleration of relativistic electrons, the magnetic field of massive stars, and finally the non-thermal emission processes relevant to the case of massive stars. Second, this general qualitative discussion will be followed by a more quantitative one, devoted to the most probable scenario where non-thermal radio emitters are massive binaries. I will show how several stellar, wind and orbital parameters can be combined in order to make some semi-quantitative predictions on the high-energy counterpart to the non-thermal emission detected in the radio domain. These theoretical considerations will be followed by a census of results obtained so far, and related to this topic. These results concern the radio, the visible, the X-ray and the gamma-ray domains. Prospects for the very high energy gamma-ray emission from massive stars will also be addressed. Two particularly interesting examples-one O-type and one Wolf-Rayet binary-will be considered in details. Finally, strategies for future developments in this field will be discussed. [less ▲]

Detailed reference viewed: 23 (8 ULg)