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See detailThe first successful crystallization of a prokaryotic extremely thermophilic outer surface layer glycoprotein
Evrard, Christine ULg; Declercq, Jean-Paul; Debaerdemaeker, Tony et al

in Zeitschrift für Kristallographie (1999), 214

Methanothermus fervidus belongs to the group of hyperthermophilic Archaea. The Archaea comprise organisms that live under environmental extremes. like high temperature, low pH value or high salt ... [more ▼]

Methanothermus fervidus belongs to the group of hyperthermophilic Archaea. The Archaea comprise organisms that live under environmental extremes. like high temperature, low pH value or high salt concentration. The outer surface of the pseudomurein sacculi of the cells of Methanothermus fervidus is covered by glycoprotein subunits (S-Iayer) directly exposed to the extreme environment. The elucidation of the crystal structure of this surface glycoprotein may provide important information on the survival strategies of these unusual micro-organisms. Before our investigations neither three-dimensional crystals have been obtained nor X-ray analyses were performed. Only electron microscopic and computer image enhancement techniques have been applied to obtain structural information from crystalline two-dimensional S-layer sheets. We describe here the successful crystallization of this surface glycoprotein under microgravity conditions. [less ▲]

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See detailFirst supplement to the catalog of observed periods of AP stars
Catalano, F. A.; Renson, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1988), 72

Supplementary data on the periods of Ap stars with references are presented; 58 new stars are introduced for which periodic variability has been discovered since 1983. For some of these stars periodicity ... [more ▼]

Supplementary data on the periods of Ap stars with references are presented; 58 new stars are introduced for which periodic variability has been discovered since 1983. For some of these stars periodicity was known before 1983 but they were not reported in the previous catalogue. Recently attributed variable star names are also reported. [less ▲]

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See detailFirst Survey on the Use of Antibiotics in Pig and Poultry Production in the Red River Delta Region of Vietnam
Pham Kim, Dang; Saegerman, Claude ULg; Douny, Caroline ULg et al

in Food and Public Health (2013), 3(5), 247-256

In Vietnam where epidemics occur regularly in animal production, the farmers consider antibiotics as one of the solutions to fight against livestock diseases, thus the risk of abuse, even illegal use of ... [more ▼]

In Vietnam where epidemics occur regularly in animal production, the farmers consider antibiotics as one of the solutions to fight against livestock diseases, thus the risk of abuse, even illegal use of antibiotics in livestock is very high. However, this is a recent issue and has not yet been thoroughly investigated. A cross-sectional study on the use of antibiotics in pig and poultry production as well as the farmer’s knowledge on the danger of the antibiotic use in three different animal production systems (farm household, semi-industrial and industrial) was conducted from July 2009 to March 2010 on 270 entities, in 3 representative localities of the Red River Delta (RRD). The results showed that a large volume of antibiotics was used arbitrary in all animal production systems. Animals were not only treated for acute diseases, but also for disease prevention, and for growth promotion. At least 45 antibiotics of more than 10 classes were used. Fifteen antibiotics were used in pig and poultry feed. For diseases treatment and prevention, antibiotics were used abusively and even illegally (e.g. chloramphenicol) by both farmers and veterinarians. The findings of this survey will permit developing new strategies for prudent use of antibiotics in livestock in Vietnam. These results will help not only to strengthen issues such as veterinary networks; antibiotics use guidance, residues monitoring systems and food safety, but also to improve awareness and ethics of producers and veterinary drug sellers. [less ▲]

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See detailFirst synthesis of 4-substituted benzenesulfonylcyanoguanidines
Masereel, B.; Lebrun, P.; Dogne, J.-M. et al

in Tetrahedron Letters (1996), 37

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See detailFirst synthesis of a '1,2-diquinone-calix[4]arene'. Interaction of its reduced form with Ag+
Vataj, Rame; Ridaoui, Hassan; Louati, Alain et al

in Journal of Electroanalytical Chemistry (2002), 519(1-2), 123129

Electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions ... [more ▼]

Electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions, affords the corresponding '1,2-diquinonecalix[4]arene' (4). The formation of 4 results from nucleophilic attack of residual water on anodically generated diphenoxylium. cations. Preliminary voltammetric experiments in CH3CN on a platinum electrode showed that 4 is suitable for electrochemical detection of the silver metal cation. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailThe first three billion years of life Evolution
Javaux, Emmanuelle ULg

Conference (2013, June)

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See detailFirst trends towards a field odour detector for environmental applications
Nicolas, Jacques ULg; Romain, Anne-Claude ULg; Wiertz, V. et al

in Weimar, Udo (Ed.) Proceedings of ISOEN 99 (1999)

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See detailFirst unambiguous asteroseismologic modelling of a gamma Doradus star
Moya, A.; Grigahcene, A.; Suárez, J. C. et al

in Memorie della Società Astronomica Italiana : Journal of the Italian Astronomical Society (2006), 77

An asteroseismologic model of the gamma Dor star 9 Aurigae is discussed in this work. This is the first time a complete asteroseismologic scheme for analyzing gamma Dor stars is applied. From standard ... [more ▼]

An asteroseismologic model of the gamma Dor star 9 Aurigae is discussed in this work. This is the first time a complete asteroseismologic scheme for analyzing gamma Dor stars is applied. From standard photometric observations (at least three oscillation frequencies, a photometric error box in the HR diagram and multicolor photometric observations, in this case in the Strömgren system) we can reduce the possible theoretical models for this star, providing constraints to the stellar parameters as mass, overshooting, metallicity, MLT parameter alpha , Brunt-Väiälä integral (I[SUB]th[/SUB]), etc. Simultaneously, an estimate of the modal identification of the observed frequencies is also obtained. This can be possible by the application, for the first time, of a complete procedure where different theoretical and computational techniques, recently developed, are linked and compared with photometric observations. The Frequency Ratio Method (FRM) and the Time Dependent Convection (TDC) theory are the basis of this complete procedure. [less ▲]

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See detailThe first Upper Paleolithic human remains from Belgium: Aurignacian, Gravettian and Magdalenian fossils at the “troisième caverne” of Goyet
Rougier, H.; Crevecoeur, I.; Beauval, C. et al

Poster (2013)

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See detailFirst vortex entry into a perpendicularly magnetized superconducting thin film
Gutierrrez, Joffre; Raes, Bart; Van de Vondel, Joris et al

in Physical Review. B : Condensed Matter (2013), 88

In type-II superconductors, the flux-free state (Meissner state) may be invaded by vortices bearing quantized flux once H is above the lower critical field Hc1. However, the actual first flux penetration ... [more ▼]

In type-II superconductors, the flux-free state (Meissner state) may be invaded by vortices bearing quantized flux once H is above the lower critical field Hc1. However, the actual first flux penetration does not occur at Hc1 due to the presence of a surface barrier and the fact that the Meissner state may also exist as a metastable state up to a larger (superheating) field. In this work we determine the field for the first vortex penetration in superconductors, by directly imaging the first vortex threading a superconducting Pb film with antidots. We find that the first vortex penetration occurs when the surface superconducting currents reach the depairing current, locally breaking superconductivity and allowing a vortex to nucleate. [less ▲]

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See detailThe First World War in French Children's Literature of Today: Between Pacifism and Unilateral View
Delbrassine, Daniel ULg

in Hans-Heino Ewers (Ed.) Erster Weltkrieg: Kindheit, Jugend und Literatur (2016)

Analyse d'un corpus de 22 récits (albums et romans en français, 1998-2013). Mise en évidence de certains choix narratifs et idéologiques: unilatéralisme français de la vision, pacifisme militant, silence ... [more ▼]

Analyse d'un corpus de 22 récits (albums et romans en français, 1998-2013). Mise en évidence de certains choix narratifs et idéologiques: unilatéralisme français de la vision, pacifisme militant, silence sur les causes du conflit... [less ▲]

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See detailThe first X-ray survey of Galactic Luminous Blue Variables
Nazé, Yaël ULg; Rauw, Grégor ULg; Hutsemekers, Damien ULg

in Astronomy and Astrophysics (2012), 538

Aims: The X-ray emission of massive stars has been studied when these objects are in their main-sequence phase, as well as in their Wolf-Rayet phase. However, the X-ray properties of the transitional ... [more ▼]

Aims: The X-ray emission of massive stars has been studied when these objects are in their main-sequence phase, as well as in their Wolf-Rayet phase. However, the X-ray properties of the transitional Luminous Blue Variable (LBV) phase remain unknown. Methods: Using a dedicated but limited XMM survey as well as archival XMM and Chandra observations, we performed the first X-ray survey of LBVs: about half of the known LBVs or candidate LBVs are studied. Results: Apart from the well known X-ray sources eta Car and Cyg OB2 #12, four additional LBVs are detected in this survey, though some doubt remains on the association with the X-ray source for two of these. For the other LBVs, upper limits on the flux were derived, down to $\log[L_{\rm X}/L_{\rm BOL}]-9.4$ for PCyg. This variety in the strength of the X-ray emission is discussed, with particular emphasis on the potential influence of binarity. [less ▲]

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See detailFirst year prognosis after myocardial infarction assassed from simple clinical findings
Smeets, J. P.; Foidart, G.; Dubois, Christophe ULg et al

Poster (1982, September)

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See detailFirst ‘in situ’ determination of gas transport coefficients (DO2, DAr and DN2 ) from bulk gas 2 concentration measurements (O2, N2, Ar) in natural sea ice
Crabeck, O.; Delille, Bruno ULg; Rysgaard, S. et al

in Journal of Geophysical Research. Oceans (2014), 119

We report bulk gas concentrations of O2, N2 and Ar, as well as their transport coefficients, in natural landfast subarctic sea ice in southwest Greenland. The observed bulk ice gas composition was 27.5 ... [more ▼]

We report bulk gas concentrations of O2, N2 and Ar, as well as their transport coefficients, in natural landfast subarctic sea ice in southwest Greenland. The observed bulk ice gas composition was 27.5% O2, 71.4% N2 and 1.09% Ar. Most previous studies suggest that convective transport is the main driver of gas displacement in sea ice and have neglected diffusion processes. According to our data, brines were stratified within the ice, so that no convective transport could occur within the brine system. Therefore, diffusive transport was the main driver of gas migration. By analysing the temporal evolution of an internal gas peak within the ice, we deduced the bulk gas transport coefficients for oxygen (DO2), argon (DAr) and nitrogen (DN222 ). The values fit to the few existing estimates from experimental work, and are close to the diffusivity values in water (10-5 cm2 s-124 ). We suggest that gas bubbles escaping from the brine to the atmosphere - as the ice gets more permeable during melt could be responsible for the previously reported high transport coefficients. These results underline that when there is no convective transport within the sea ice, the transport of gas by diffusion through the brines, either in the liquid or gaseous phases, is a major factor in controlling the ocean–atmosphere exchange. [less ▲]

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See detailFIRST, a fibered aperture masking instrument. I. First on-sky test results
Huby, Elsa ULg; Perrin, G.; Marchis, F. et al

in Astronomy and Astrophysics (2012), 541

Aims: In this paper we present the first on-sky results with the fibered aperture masking instrument FIRST. Its principle relies on the combination of spatial filtering and aperture masking using single ... [more ▼]

Aims: In this paper we present the first on-sky results with the fibered aperture masking instrument FIRST. Its principle relies on the combination of spatial filtering and aperture masking using single-mode fibers, a novel technique that is aimed at high dynamic range imaging with high angular resolution. Methods: The prototype has been tested with the Shane 3-m telescope at Lick Observatory. The entrance pupil is divided into sub-pupils feeding single-mode fibers. The flux injection into the fibers is optimized by a segmented mirror. The beams are spectrally dispersed and recombined in a non-redundant exit configuration in order to retrieve all contrasts and phases independently. Results: The instrument works at visible wavelengths between 600 nm and 760 nm and currently uses nine of the 30 43 cm sub-apertures constituting the full pupil. First fringes were obtained on Vega and Deneb. Stable closure phases were measured with standard deviations on the order of 1 degree. Closure phase precision can be further improved by addressing some of the remaining sources of systematic errors. While the number of fibers used in the experiment was too small to reliably estimate visibility amplitudes, we have measured closure amplitudes with a precision of 10% in the best case. Conclusions: These first promising results obtained under real observing conditions validate the concept of the fibered aperture masking instrument and open the way for a new type of ground-based instrument working in the visible. The next steps of the development will be to improve the stability and the sensitivity of the instrument in order to achieve more accurate closure phase and visibility measurements, and to increase the number of sub-pupils to reach full pupil coverage. [less ▲]

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See detailFIRST, a fibered aperture masking instrument. II. Spectroscopy of the Capella binary system at the diffraction limit
Huby, Elsa ULg; Duchêne, G.; Marchis, F. et al

in Astronomy and Astrophysics (2013), 560

Aims: FIRST is a prototype instrument built to demonstrate the capabilities of the pupil remapping technique, using single-mode fibers and working at visible wavelengths. Our immediate objective is to ... [more ▼]

Aims: FIRST is a prototype instrument built to demonstrate the capabilities of the pupil remapping technique, using single-mode fibers and working at visible wavelengths. Our immediate objective is to demonstrate the high angular resolution capability of the instrument and to show that the spectral resolution of the instrument enables characterization of stellar companions. Methods: The FIRST-18 instrument is an improved version of FIRST-9 that simultaneously recombines two sets of nine fibers instead of one, thus greatly enhancing the (u, v) plane coverage. We report on observations of the binary system Capella at three epochs over a period of 14 months (≳4 orbital periods) with FIRST-18 mounted on the 3 m Shane telescope at Lick Observatory. The binary separation during our observations ranges from 0.8 to 1.2 times the diffraction limit of the telescope at the central wavelength of the spectral band. Results: We successfully resolved the Capella binary system at all epochs, with an astrometric precision as good as 1 mas under the best observing conditions. FIRST also gives access to the spectral flux ratio between the two components directly measured with an unprecedented spectral resolution of R ~ 300 over the 600-850 nm range. In particular, our data allow detection of the well-known overall slope of the flux ratio spectrum, leading to an estimation of the "pivot" wavelength of 0.64 ± 0.01 μm, at which the cooler component becomes the brightest. Spectral features arising from the difference in effective temperature of the two components (specifically the Hα line, TiO, and CN bands) have been used to constrain the stellar parameters. The effective temperatures we derive for both components are slightly lower (5-7%) than the well-established properties for this system. This difference mainly comes from deeper molecular features than those predicted by state-of-the-art stellar atmospheric models, suggesting that molecular line lists used in the photospheric models are incomplete and/or oscillator strengths are underestimated, most likely concerning the CN molecule. Conclusions: These results demonstrate the power of FIRST, which is a fibered pupil remapping-based instrument, in terms of high angular resolution and show that the direct measurement of the spectral flux ratio provides valuable information to characterize little known companions. [less ▲]

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