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See detailHard pomeron contribution to forward elastic scattering
Cudell, Jean-René ULg; Lengyel, A.; Martynov, E. et al

in Nicolescu, B. (Ed.) Conference On Elastic And Diffractive Scattering: Towards High Energy Frontiers: The 20th Anniversary Of The Blois Workshops (2005)

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See detailThe hard pomeron in soft data
Cudell, Jean-René ULg; Martynov, Evgenij; Selyugin, Oleg Viktorovich et al

in Physics Letters B (2004), 587(1-2), 78-86

We show that the data for the total cross section and for the real part of the elastic amplitude indicate the presence of a hard pomeron in pip and Kp elastic scattering at t = 0, compatible with that ... [more ▼]

We show that the data for the total cross section and for the real part of the elastic amplitude indicate the presence of a hard pomeron in pip and Kp elastic scattering at t = 0, compatible with that observed in deep inelastic scattering. We show that such a hard pomeron is also compatible with pp and pp data, provided one unitarises it at high energy. (C) 2004 Published by Elsevier B.V. [less ▲]

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See detailHard Selective Sweep and Ectopic Gene Conversion in a Gene Cluster Affording Environmental Adaptation
Hanikenne, Marc ULg; Kroymann, Juergen; Trampczynska, Aleksandra et al

in PLoS Genetics (2013), 9

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See detailHard X-ray emission clumps in the gamma-Cygni supernova remnant: An INTEGRAL-ISGRI view
Bykov, A. M.; Krassilchtchikov, A. M.; Uvarov, Y. A. et al

in Astronomy and Astrophysics (2004), 427(3), 21-24

Spatially resolved images of the galactic supernova remnant G78.2+2.1 (gamma-Cygni) in hard X-ray energy bands from 25 keV to 120 keV are obtained with the IBIS-ISGRI imager aboard the International Gamma ... [more ▼]

Spatially resolved images of the galactic supernova remnant G78.2+2.1 (gamma-Cygni) in hard X-ray energy bands from 25 keV to 120 keV are obtained with the IBIS-ISGRI imager aboard the International Gamma-Ray Astrophysics Laboratory INTEGRAL. The images are dominated by localized clumps of about ten arcmin in size. The flux of the most prominent North-Western (NW) clump is (1.7+/-0.4)x10(-11) erg cm(-2) s(-1) in the 25-40 keV band. The observed X-ray fluxes are in agreement with extrapolations of soft X-ray imaging observations of gamma-Cyg by ASCA GIS and spatially unresolved RXTE PCA data. The positions of the hard X-ray clumps correlate with bright patches of optical line emission, possibly indicating the presence of radiative shock waves in a shocked cloud. The observed spatial structure and spectra are consistent with model predictions of hard X-ray emission from nonthermal electrons accelerated by a radiative shock in a supernova interacting with an interstellar cloud, but the powerful stellar wind of the O9V star HD 193322 is a plausible candidate for the NW source as well. [less ▲]

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See detailHard X-ray emission from eta Carinae
Leyder, Jean-Christophe ULg; Walter, R.; Rauw, Grégor ULg

in Astronomy and Astrophysics (2008), 477

Context: If relativistic particle acceleration takes place in colliding-wind binaries, hard X-rays and gamma-rays are expected through inverse Compton emission, but to date these have never been ... [more ▼]

Context: If relativistic particle acceleration takes place in colliding-wind binaries, hard X-rays and gamma-rays are expected through inverse Compton emission, but to date these have never been unambiguously detected. Aims: To detect this emission, observations of eta Carinae were performed with INTEGRAL, leveraging its high spatial resolution. Methods: Deep hard X-ray images of the region of eta Car were constructed in several energy bands. Results: The hard X-ray emission previously detected by BeppoSax around eta Car originates from at least 3 different point sources. The emission of eta Car itself can be isolated for the first time, and its spectrum unambiguously analyzed. The X-ray emission of eta Car in the 22-100 keV energy range is very hard (Gamma ~= 1 ± 0.4) and its luminosity is 7 × 10^33 erg s^-1. Conclusions: The observed emission is in agreement with the predictions of inverse Compton models, and corresponds to about 0.1% of the energy available in the wind collision. eta Car is expected to be detected in the GeV energy range. [less ▲]

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See detailHard X-ray identification of η Carinae and steadiness close to periastron
Leyder, Jean-Christophe ULg; Walter, R.; Rauw, Grégor ULg

in Astronomy and Astrophysics (2010), 524

Context. The colliding-wind binary η Carinae exhibits soft X-ray thermal emission that varies strongly around the periastron passage. It has been found to have non-thermal emission, thanks to its ... [more ▼]

Context. The colliding-wind binary η Carinae exhibits soft X-ray thermal emission that varies strongly around the periastron passage. It has been found to have non-thermal emission, thanks to its detection in hard X-rays using INTEGRAL and Suzaku, and also in γ-rays with AGILE and Fermi. <BR /> Aims: This paper attempts to definitively identify η Carinae as the source of the hard X-ray emission, to examine how changes in the 2-10 keV band influence changes in the hard X-ray band, and to understand more clearly the mechanisms producing the non-thermal emission using new INTEGRAL observations obtained close to periastron passage. <BR /> Methods: To strengthen the identification of η Carinae with the hard X-ray source, a long Chandra observation encompassing the INTEGRAL/ISGRI error circle was analysed, and all other soft X-ray sources (including the outer shell of η Carinae itself) were discarded as likely counter-parts. To expand the knowledge of the physical processes governing the X-ray lightcurve, new hard X-ray images of η Carinae were studied close to periastron, and compared to previous observations far from periastron. <BR /> Results: The INTEGRAL component, when represented by a power law (with a photon index Γ of 1.8), would produce more emission in the Chandra band than observed from any point source in the ISGRI error circle apart from η Carinae, as long as the hydrogen column density to the ISGRI source is lower than N[SUB]H[/SUB] ≲ 10[SUP]24[/SUP] cm[SUP]-2[/SUP]. Sources with such a high absorption are very rare, thus the hard X-ray emission is very likely to be associated with η Carinae. The eventual contribution of the outer shell to the non-thermal component also remains fairly limited. Close to periastron passage, a 3-σ detection is achieved for the hard X-ray emission of η Carinae, with a flux similar to the average value far from periastron. <BR /> Conclusions: Assuming a single absorption component for both the thermal and non-thermal sources, this 3-σ detection can be explained with a hydrogen column density that does not exceed N[SUB]H[/SUB] ≲ 6 × 10[SUP]23[/SUP] cm[SUP]-2[/SUP] without resorting to an intrinsic increase in the hard X-ray emission. The energy injected in hard X-rays (averaged over a month timescale) appears to be rather constant at least as close as a few stellar radii, well within the acceleration region of the wind. [less ▲]

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See detailA Hare and Hound in a BAG: Asteroseismology of Beta Cephei stars
Thoul, Anne ULg; Ausseloos, M.; Barban, C. et al

in Communications in Asteroseismology (2003), 143

Several members of the COROT Seismology Working Group (SWG) have performed several ``hare-and-hound'' exercises to prepare the data exploitation of the mission in the past few years. These exercises ... [more ▼]

Several members of the COROT Seismology Working Group (SWG) have performed several ``hare-and-hound'' exercises to prepare the data exploitation of the mission in the past few years. These exercises consist in reproducing a theoretical model on the basis of a light curve obtained from a frequency spectrum computed from an ``unknown'' theoretical model of a solar-like or a Delta Scuti star. Members of the BAG (Belgian Asteroseismology Group) have now shown that such an exercise in the mass range of Beta Cephei stars is extremely convincing, making these stars excellent targets for asteroseismology space missions. [less ▲]

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See detailHARELBKE LOCK (Design & Build Procedure)
Rigo, Philippe ULg; DEROUCK, Julien

Report (2012)

Three proposals have been received by the Waterwegen en Zeekanaal NV . This report reviews these proposals of lock design in the framework of HARELBKE LOCK (Design & Build Procedure)

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See detailLe haricot de Lima
Baudoin, Jean-Pierre ULg; Mergeai, Guy ULg

in Agriculture en Agrique tropicale (2001)

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See detailLe Haricot-igname Africain (Sphenostylis stenocarpa (Hochst. ex A. Rich.) Harms) : une légumineuse à graines et à tubercules sous-exploitée
Baudoin, Jean-Pierre ULg; Kamion Ngansia, F.

in Troupeaux et Cultures des Tropiques (2004), II(IV), 44-46

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See detailHarm avoidance and serotonin.
Hansenne, Michel ULg; Ansseau, Marc ULg

in Biological Psychology (1999), 51(1), 77-81

The relationships between the Tridimensional Personality Questionnaire (TPQ) and serotonergic activity has been described in some studies with controversial results. These studies have focused on specific ... [more ▼]

The relationships between the Tridimensional Personality Questionnaire (TPQ) and serotonergic activity has been described in some studies with controversial results. These studies have focused on specific patient populations rather than normal controls. Therefore, the aim of the present study is to examine the relationships between the TPQ and serotonergic activity in a group of non-patient subjects. Twenty-three normal subjects answered the TPQ, and the serotonergic activity was assessed by the prolactin response to a highly potent and selective 5-HT1a agonist (flesinoxan). A positive relationship between harm avoidance and PRL response to flesinoxan was found. This study is consistent with the hypothesized link between serotonergic activity and the harm avoidance dimension of the biosocial model of Cloninger. [less ▲]

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See detailHarm avoidance dimension of the Tridimensional Personality Questionnaire and serotonin-1A activity in depressed patients.
Hansenne, Michel ULg; Pitchot, William ULg; Moreno, A. G. et al

in Biological Psychiatry (1997), 42(10), 959-61

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See detailHarm avoidance is related to mismatch negativity (MMN) amplitude in healthy subjects
Hansenne, Michel ULg; Pinto, Emmanuel ULg; Scantamburlo, Gabrielle ULg et al

in Personality & Individual Differences (2003), 34(6), 1039-1048

Event-related potential (ERP) studies evidenced that some personality dimensions induced different controlled cognitive attitudes towards the processing of information. However, few data are available on ... [more ▼]

Event-related potential (ERP) studies evidenced that some personality dimensions induced different controlled cognitive attitudes towards the processing of information. However, few data are available on the possible relationships between personality and automatic attention or early sensory processing. In the present study the relationships between the mismatch negativity (MMN) and personality described by the Cloninger model of personality were investigated. Subjects were 32 healthy volunteers. The MMN was recorded with frequent stimuli tones of 1470 Hz, 70 dB and 40 ms duration, and target (20%) tones of 1470 Hz, 70 dB, 80 ms duration. The subjects completed a French version of the 226-item self-questionnaire TCI within the day following psychophysiological recording. The results showed that the HA dimension was negatively correlated with the MMN amplitude. The association was more present among women than men. No significant relationship existed between the other dimensions of personality and either the MMN amplitude or latency. These findings suggest that the MMN is related to the behavioral inhibition system (BIS), a fact which is consistent with clinical studies conducted on schizophrenia and anxiety disorders. In conclusion, this study suggests that personality dimensions induce different automatic attitudes towards the processing of information. (C) 2002 Published by Elsevier Science Ltd. [less ▲]

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See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part I : Harmonine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Laurent, Pascal ULg et al

Poster (2010, January)

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly ... [more ▼]

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly polymorphic insect is problematic in several ways. It seems to outcompete native coccinellid species; they can group on fruits in vineyards and spoil wine when crushed with grapes; they can aggregate by hundreds in houses to winter. This study aims to investigate the relations between the chemical defences of H. axyridis and warning signals expressed by this bug. To achieve this goal, two original quantification methods of H. axyridis secondary metabolites have been undertaken. The first one allows Fast-GC quantifying harmonine, its main defence alkaloid. The other one permits to determine its emission rate of 2-isopropyl-3-methoxypyrazine, a highly odorous compound probably involved in the communication between individuals and in the aposematism of this insect. This last point will be detailed in another poster. Firstly, a method of extraction, acetylation and purification of harmonine from H. axyridis has been devised to obtain a calibration standard because this molecule is not commercially available. The identity of the extracted compound has been confirmed by mass spectrometry and multidimensional NMR. The GC purity of this N,N-diacetylharmonine is of 100%. During the experiments, its stability in acetone solution at 4°C has been verified. Using this purified molecule, an original method of harmonine quantification has been developed by fast gas chromatography and validated using accuracy profile. The method has been validated for concentrations ranging from 28µg/ml to more than 264µg/ml, with a maximal error risk of 20%. From about 100µg/ml, peaks symmetry decreased, but did not influence the quantification. That accuracy profile validation has been compared with a more classical validation using AOAC (2006) norm, which confirmed the first validation. This method allows quantifying harmonine in one single insect. Harmonine has been quantified in 80 H. axyridis divided into four groups of at least 15 individuals on basis of the morph type and the elytra hue. Males and females harmonine contents did not significantly differ. The mean harmonine content was of 106.6µg/individual with a standard deviation of 80.2µg/individual. The results distribution obtained was not normal and a strong variability between individuals was observed, which explains the high standard deviation. These results and those of the pyrazine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It would appear that elytra colour is linked with the insect harmonine content. Individuals with a non-melanic orange colour presented harmonine content significantly higher than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

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See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part II : Pyrazine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Marlet, Christelle ULg et al

Poster (2010, January)

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects ... [more ▼]

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects: Coleoptera: Coccinellidae). This second part describes an original quantification method for 2-isopropyl-3-methoxypyrazine (IPMP) by active sampling on thermally desorbed adsorbent (TD) coupled with GC-MS analysis. This highly odorous compound is supposed to be implicated in intra- and interspecific communication. In order to allow harmonine quantification (a defence alkaloid, see Part 1), this method avoid any hemolymph loses by the ladybird (Coccinellids can emit hemolymph when stressed). This method is non-lethal and applicable on one single insect. The quantification method has been validated from 37,5pg to 10 000 pg per adsorbent cartridge. On this range, there is no breakthrough and desorption is complete (>99.4%). At the LOQ (37.5pg/cartridge), the bias is of 20%, but rapidly decreased to less than 5% on the rest of the validated range (100 to 10 000 pg/cartridge). According to AOAC (2006) norm, this method is repeatable but not reproducible. The IPMP emission rate following a stress has been quantified on 80 H. axyridis grouped in four classes on basis of the morph type and the elytra hue. Males and females emission rates did not significantly differ. The mean emission rate is of 707 pg/4h with an extremely high standard deviation of 1766pg/4h due to a great individual variability and a strongly asymmetric distribution of the results. These results and those of the harmonine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It seems that elytra colour is linked with the insect IPMP emission rate. Individuals with a melanic red colour presented IPMP emission rate significantly lower than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

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See detailThe harmonic balance method for advanced analysis and design of nonlinear mechanical systems
Detroux, Thibaut ULg; Renson, Ludovic ULg; Kerschen, Gaëtan ULg

in Proceedings of the SEM IMAC XXXII (2014, February)

As a tool for analyzing nonlinear large-scale structures, the harmonic balance (HB) method has recently received increasing attention in the structural dynamics community. However, its use was so far ... [more ▼]

As a tool for analyzing nonlinear large-scale structures, the harmonic balance (HB) method has recently received increasing attention in the structural dynamics community. However, its use was so far limited to the approximation and study of periodic solutions, and other methods as the shooting and orthogonal collocation techniques were usually preferred to further analyze these solutions and to study their bifurcations. This is why the present paper intends to demonstrate how one can take advantage of the HB method as an efficient alternative to the cited techniques. Two different applications are studied, namely the normal modes of a spacecraft and the optimization of the design of a vibration absorber. The interesting filtering feature of the HB method and the implementation of an efficient bifurcation tracking extension are illustrated. [less ▲]

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