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
Full Text
Peer Reviewed
See detailEvolution of the polarization of the optical afterglow of the γ-ray burst GRB030329
Greiner, Jochen; Klose, Sylvio; Reinsch, Klaus et al

in Nature (2003), 426

The association of a supernova with GRB030329 strongly supports the `collapsar' model of γ-ray bursts, where a relativistic jet forms after the progenitor star collapses. Such jets cannot be spatially ... [more ▼]

The association of a supernova with GRB030329 strongly supports the `collapsar' model of γ-ray bursts, where a relativistic jet forms after the progenitor star collapses. Such jets cannot be spatially resolved because γ-ray bursts lie at cosmological distances; their existence is instead inferred from `breaks' in the light curves of the afterglows, and from the theoretical desire to reduce the estimated total energy of the burst by proposing that most of it comes out in narrow beams. Temporal evolution of the polarization of the afterglows may provide independent evidence for the jet structure of the relativistic outflow. Small-level polarization (~1-3 per cent) has been reported for a few bursts, but its temporal evolution has yet to be established. Here we report polarimetric observations of the afterglow of GRB030329. We establish the polarization light curve, detect sustained polarization at the per cent level, and find significant variability. The data imply that the afterglow magnetic field has a small coherence length and is mostly random, probably generated by turbulence, in contrast with the picture arising from the high polarization detected in the prompt γ-rays from GRB021206 (ref. 18). [less ▲]

Detailed reference viewed: 10 (0 ULg)
See detailEvolution of the populations of Cystoseira balearica (Phaeophyceae) and epiphytic Bangiophyceae in the Bay of Calvi (Corsica) in the last eight years
Hoffman, Lucien; Clarisse, Serge; Detienne, Xavier et al

in Bulletin de la Société Royale des Sciences de Liège (1988), 4-5

In a number of stations covering the Bay of Calvi (Corsica, Mediterranean Sea) we studied the development of the macroscopic brown alga Cyctoseira balearica and of the epiphytic microscopic Bangiophyceae ... [more ▼]

In a number of stations covering the Bay of Calvi (Corsica, Mediterranean Sea) we studied the development of the macroscopic brown alga Cyctoseira balearica and of the epiphytic microscopic Bangiophyceae. Cystoseira balearica is a major component of infralittoral communities on rocky substrates and Bangiophyceae have been considered indicators of eutrophication. The epiphytic Bangiophyceae have indeed their optimal developement near the sewages discharges (especially in summer) and near the town of Calvi. Since 1981 an increase is observed in the abundance of the Bangiophycae. Cystoseira balearica, a pollution-sensitive species, is not present in the harbours of the town of Cavi and near the sewage dicharges. Since 1980 the coverage and the standing crop of this alga have decreased. The increase of Bangiophyceae and the concurrent decrease of Cyctoseira balearica seem to indicate an increasing pollution of the waters of the Bay of Calvi in the period 1980 - 1988. [less ▲]

Detailed reference viewed: 85 (16 ULg)
Full Text
See detailEvolution of the prevalence and characteristics of anemia in inflammatory bowel diseases between 1993 and 2003
Vijverman, A.; Piront, Patricia ULg; Belaiche, Jacques ULg et al

in Acta Gastro-Enterologica Belgica (2006), 69(1, Jan-Mar), 1-4

Introduction : Anemia has been considered as an overlooked complication of inflammatory bowel disease. Studies dating back to the 80ties and the 90ties have shown 30% of anemia among inflammatory bowel ... [more ▼]

Introduction : Anemia has been considered as an overlooked complication of inflammatory bowel disease. Studies dating back to the 80ties and the 90ties have shown 30% of anemia among inflammatory bowel disease (IBD) patients. More recently, the broader use of immunosuppressive drug and infliximab allowing better mucosal healing as well as a more aggressive treatment of anemia, including the use of safer form of IV iron, may have influenced the prevalence of anemia among IBD patients. Our aim was to asses the prevalence and characteristics of anemia among two cohorts of IBD patients at 10 years interval and to look for associated clinical or demographic factors. Methods: using the IBD patients register of one senior gastroenterologist, we identified IBD patients he had consecutively seen and who had blood test at the outpatient clinic during the years 1993 and 2003. Demographic and clinical characteristics, treatment for Crohn's disease, blood test results and treatment of anemia were recorded and compared between these two cohorts. Anemia was defined as an hemoglobin level lower than the normal value of the laboratory of our hospital. Results : 80 and 90 patients were identified in 1993 and 2003, respectively. There was no significant difference between the two cohorts, according to age, gender, disease type, duration or location. There were 27/80 (33.8%) and 15/90 (16.7%) anemic patients in 1993 and 2003, respectively (P = 0.013). The prevalence of severe anemia (hemoglobin level < 10.5 g/100 ml) was similar in the two cohorts (6.3% and 5.6%). Characteristics of the anemia were similar in the two cohorts with a majority of iron deficiency anemia and inflammatory anemia. Ferritin and CRP levels were not significantly different in the two cohorts. The only significant difference was a more frequent use of immunosuppressive treatment and infliximab in 2003 than in 1993 (33.3% vs. 13.8%; P = 0.0038, RR :0.41, 0.22-0.77) Conclusions : Prevalence of mild to moderate anemia has significantly decreased in our population over the last 10 years. The only difference detected between the two cohorts was the increased use of immunosuppressive drug (mainly azathioprine). [less ▲]

Detailed reference viewed: 38 (0 ULg)
See detailEvolution of the shoot density of the Posidonia oceanica bed of Calvi Bay (Corsica).
Soullard, Mady; Dauby, Patrick ULg; Bouquegneau, Jean-Marie ULg

Conference (1992, February)

Detailed reference viewed: 9 (0 ULg)
Peer Reviewed
See detailEvolution of the surface chemistry of carbon xerogels with very different textural properties by chemical activation and oxidation
Zubizarreta, Leire; Arenillas, A.; Pirard, Jean-Paul ULg et al

Poster (2009, June 14)

Detailed reference viewed: 19 (1 ULg)
Full Text
Peer Reviewed
See detailEvolution of the surface chemistry of carbon xerogels with very different textural properties by chemical activation and oxidation
Zubizaretta, Leire; Arenillas, A.; Pirard, Jean-Paul ULg et al

in Proceedings of the International Carbon Conference 2009 (2009)

Detailed reference viewed: 12 (1 ULg)
Full Text
See detailEvolution of the theoretical power spectrum of solar-like oscillations along the ascending phase on the red giant branch.
Grosjean, Mathieu ULg; Dupret, Marc-Antoine ULg; Belkacem, Kevin et al

in Astronomical Society of the Pacific Conference Series (2013, December), 479

CoRoT and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. An important question comes from the observation of mixed ... [more ▼]

CoRoT and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. An important question comes from the observation of mixed modes : When during the star’s ascension on the RGB are mixed-modes more likely to be detectable ? We follow the evolution of a star on the RGB and investigate the effect of its ascension on theoretical power spectrum. Equilibrium models (computed with the code ATON) represent four different stages of a star on the RGB. The mass of the star (1.5M") is in the typical mass range of stars observed by CoRoT and Kepler. We used a non-radial non-adiabatic code to compute the theoretical solar-like oscillations of these models. An important output of these calculations is the theoretical lifetimes of the modes. Then we computed the oscillation amplitudes through a stochastic excitation model. These computations allow us to draw theoretical power spectrum and discuss the possibility to observe mixed-modes at different evolutionary stages on the RGB. We found that structure modifications in a star ascending the RGB have an important impact on theoretical power spectrum of solar-like oscillations. Efficiencies of trapping and lifetimes of mixed modes are indeed strongly affected by this evolution. [less ▲]

Detailed reference viewed: 18 (2 ULg)
Full Text
See detailEvolution of the theoretical power spectrum of solar-like oscillations along the ascending phase on the red giant branch.
Grosjean, Mathieu ULg; Montalban Iglesias, Josefa ULg; Samadi, Reza et al

Poster (2012, November)

CoRoT and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. An important question comes from the observation of mixed ... [more ▼]

CoRoT and Kepler observations of red giants reveal rich spectra of non-radial solar-like oscillations allowing to probe their internal structure. An important question comes from the observation of mixed modes : When during the star’s ascension on the RGB are mixed-modes more likely to be detectable ? We follow the evolution of a star on the RGB and investigate the effect of its ascension on theoretical power spectrum. Equilibrium models (computed with the code ATON) represent four different stages of a star on the RGB. The mass of the star (1.5M") is in the typical mass range of stars observed by CoRoT and Kepler. We used a non-radial non-adiabatic code to compute the theoretical solar-like oscillations of these models. An important output of these calculations is the theoretical lifetimes of the modes. Then we computed the oscillation amplitudes through a stochastic excitation model. These computations allow us to draw theoretical power spectrum and discuss the possibility to observe mixed-modes at different evolutionary stages on the RGB. We found that structure modifications in a star ascending the RGB have an important impact on theoretical power spectrum of solar-like oscillations. Efficiencies of trapping and lifetimes of mixed modes are indeed strongly affected by this evolution. [less ▲]

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailThe Evolution Of The Volatile Compounds By Aging, In Apple Vinegar Flavored With Rosmarinus Officinalis L., Using A HS/GC-MS Technique
Truta, Delia-Mihaela ULg; Tofana, Maria; Socaci, Sonia Ancuta

in Journal of Agroalimentary Processes and Technologies (2010), 16(2), 155-158

Apple vinegar, made from apple juice or concentrated apple juice throuth a double fermentation, it’s widely used as a beverage and food preserver in traditional medicine and healthy diets. The apple ... [more ▼]

Apple vinegar, made from apple juice or concentrated apple juice throuth a double fermentation, it’s widely used as a beverage and food preserver in traditional medicine and healthy diets. The apple vinegar used in this study was flavored using 2 methods of extraction for the active principles from Rosmarinus officinalis L.: maceration and ultrasounds. This paper aims for the analysis and identification of the biological active compounds from the flavored vinegar, using a Headspace /Gas Chromatographic – Mass Spectrometry analysis, at the bottling of the process and after a year of aging the vinegar in glass bottles. A various number of volatile compounds, specific to rosemary, were identified in the vinegar also from the beginning of bottling. The volatile compounds ranged during the aging process, but the main ones, that were specific to rosemary, and to the apple vinegar, were the same. [less ▲]

Detailed reference viewed: 14 (4 ULg)
See detailEvolution of time measurement in Astronomy
Biémont, Emile ULg

in Heck, A. (Ed.) Information Handling in Astronomy - Historical Vistas (2003)

Detailed reference viewed: 7 (1 ULg)
Peer Reviewed
See detailEvolution of Treatment and Investigative Approaches in Sleep Medicine
Ly, Julien; Chellappa, Sarah Laxhmi ULg; MAQUET, Pierre ULg

in Billiard, Michael (Ed.) Sleep Medicine: a comprehensive guide (in press)

Detailed reference viewed: 32 (12 ULg)
Full Text
Peer Reviewed
See detailEvolution of vacuum states and phase transitions in the two Higgs doublet model during cooling of the Universe
Ginzburg, Ilya; Ivanov, Igor ULg; Kanishev, Konstantin

in Physical Review. D : Particles and Fields (2010), 81

We consider the evolution of the ground state in the two Higgs doublet model during cooling down of the Universe after the big bang. Different regions in the space of free parameters of this model ... [more ▼]

We consider the evolution of the ground state in the two Higgs doublet model during cooling down of the Universe after the big bang. Different regions in the space of free parameters of this model correspond to different sequences of thermal phase transitions. We discuss different paths of thermal evolution and corresponding evolution of physical properties of the system for different modern values of the parameters. [less ▲]

Detailed reference viewed: 17 (4 ULg)
Peer Reviewed
See detailEvolution of ventriculo-arterial coupling during acute myocardial ischemia
Kolh, Philippe ULg; D'Orio, Vincenzo ULg; LAMBERMONT, Bernard ULg et al

in European Heart Journal (2001), 22

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
See detailEvolution of Western Mediterranean Sea Surface Temperature between 1985 and 2005
Troupin, Charles ULg; Lenartz, Fabian; Sirjacobs, Damien ULg et al

Conference (2009, April 20)

Detailed reference viewed: 19 (3 ULg)
Full Text
Peer Reviewed
See detailEvolution of wind behaviour and of its potential for wind power production in Belgium during the last 22 years : a comparison between WRF forced by NCEP2 reanalysis and WRF forced by ERA-INTERIM reanalysis
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Conference (2011, September 16)

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is ... [more ▼]

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is dependent on the weather. This implies that the wind production is irregular at a very short time scale. But the short time scale availability of the wind-based energy is important to the producers of energy as well as to the electric grid managers because the wind energy production can rise or fall rapidly which creates some financial and voltage variations. For these reasons, we study the past evolution of the availability of the wind quantity by analysing the intermittence of the wind speed in Belgium during the last 22 years (1989-2010). To reach this goal, we use the regional model WRF (Weather and Research Forecast model) developed by the UCAR community users. In a first time, the WRF model is forced by the NCEP2 reanalysis outputs to obtain a regionalisation of the weather conditions over a domain centred on Belgium at a resolution of 10 km. This resolution allows to capture the minute-based time scale variability of wind speed and consequently the irregular behaviour of the wind power production. In a second time, the WRF model is forced by the ERA-Interim reanalysis outputs with the same configuration. To obtain a value of the wind intermittence, we calculate the persistence of a wind blowing continuously with a minimum speed of 1 ms-1, then the persistence of a wind blowing continuously with a minimum speed of 2 ms-1, etc. The persistence of the wind speed and its evolution over 22 years are characterised by : (a) the mean wind speed over a fixed period (monthly, seasonally, … ), (b) the mean duration of a wind speed above x ms-1 over the same fixed period and (c) the evolution of (a) and (b) during the studied period. This analysis is made with the outputs of WRF-NCEP2 and with the outputs of WRF-Interim allowing to evaluate the impact of forcing fields into WRF-based wind climatology. [less ▲]

Detailed reference viewed: 109 (9 ULg)
Full Text
See detailEvolution of wind behaviour and of its potential for wind power production in Belgium during the last 30 years.
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Sacré, Bernard ULg et al

Poster (2011, April 04)

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is ... [more ▼]

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is dependent on the weather. This implies that the wind production is irregular at a very short time scale. But the short time scale availability of the wind-based energy is important to the producers of energy as well as to the electric grid managers because the wind energy production can rise or fall rapidly which creates some financial and voltage variations. For these reasons, we study the past evolution of the availability of the wind quantity by analysing the intermittence of the wind speed in Belgium during the last 30 years. To reach this goal, we use the regional model WRF (Weather and Research Forecast model) developed by the UCAR community users. The WRF model is forced by the NCEP2 Reanalysis model to obtain a regionalisation of the weather conditions over a domain centred on Belgium at a spatiotemporal resolution of 10 km and 1 min. This resolution allows to capture the minute-based time scale variability of wind speed and consequently the irregular behaviour of the wind power production. To obtain a value of the wind intermittence, we calculate the persistence of a wind blowing continuously with a minimum speed of 1 ms-1, then the persistence of a wind blowing continuously with a minimum speed of 2 ms-1, etc. The persistence of the wind speed and its evolution over 30 years are characterised by : (a) the mean wind speed over a fixed period (monthly, seasonally, … ), (b) the mean duration of a wind speed above x ms-1 over the same fixed period and (c) the evolution of (a) and (b) during the studied period. This study will show the evolution during the last decades of the wind behaviour in Belgium and its potential for electricity production. [less ▲]

Detailed reference viewed: 59 (8 ULg)
Peer Reviewed
See detailEvolution on trees: a brief review about the extinctions of species, and the case of genocide in a Darwinistic punctuated equilibrium evolution model
Ausloos, Marcel ULg; Kramer, M.; Vandewalle, Nicolas ULg

in Physica A: Statistical Mechanics and its Applications (1999), 273(1-2), 33-45

Numerical and theoretical investigations of species evolution in presence of extinction rules are recalled in the framework of punctuated equilibrium evolution models. Previous results, on the Bak-Sneppen ... [more ▼]

Numerical and theoretical investigations of species evolution in presence of extinction rules are recalled in the framework of punctuated equilibrium evolution models. Previous results, on the Bak-Sneppen model are mentioned together with extensions taking into account a variable number of species. Conditions for limited growth due to species interactions, external fields, or intrinsic population density conditions have already been considered. An original genocide model is presented as a step towards describing effects due to the extinction of species. Critical exponents for (i) the avalanche distribution. (ii) the teady-state approach, and (iii) the tree size are given. A mean-field approximation is shown to be quite accurate for describing the critical state. The screening of species from the evolution process is not numerically studied. [less ▲]

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailEvolution over a 10 year period of the epidemiological profile of 1,726 newly diagnosed HCV patients in Belgium.
Gerard, Christiane ULg; Delwaide, Jean ULg; Vaira, Dolorès ULg et al

in Journal of Medical Virology (2005), 76(4), 503-10

In order to evaluate the future burden of hepatitis C, there is a need to quantify the evolution with time of some crucial parameters such as disease frequency and age, modes of infection and infecting ... [more ▼]

In order to evaluate the future burden of hepatitis C, there is a need to quantify the evolution with time of some crucial parameters such as disease frequency and age, modes of infection and infecting genotypes of patients presenting for the first time at consultation. The yearly evolution of these parameters was analyzed retrospectively in a cohort of 1,726 patients living in Belgium, who were diagnosed as hepatitis C virus (HCV) carriers by polymerase chain reaction (PCR) between 1992 and 2002. The epidemiological profile of HCV patients showed significant changes during this period. The number of new patients increased with time. The proportion of patients under 50 increased linearly at a rate of 3% per year. The rate of newly presenting patients infected by transfusion before 1990 decreased, but only by 2.7% per year. The proportion of intravenous (IV) drug users increased by 2.5% per year. Patients presenting "undefined" risk factors increased by 2.1% per year. Nosocomial acquisition of HCV infection exhibited a disturbing relative stability in time whereas dialysis tended to disappear as a cause of infection. There was a significant linear annual decrease of 2.3% in the frequency of genotype 1b, which was counterbalanced by a significant increase of 0.7% for genotype 1a and 1.1% for genotype 4. Genotypes 2 and 3 did not vary significantly with time. Such figures are useful for evaluating the epidemiological changes of C virus infection and for anticipating the future economical cost of hepatitis C treatment in the next few years. [less ▲]

Detailed reference viewed: 49 (6 ULg)