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See detailErratum to "Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b"
Gillon, Michaël ULg; Demory, B*-O; Barman, T. et al

in Astronomy and Astrophysics (2008), 490

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See detailTW ;Hydrae: evidence of stellar spots instead of a Hot Jupiter
Huélamo, N.; Figueira, P.; Bonfils, X. et al

in Astronomy and Astrophysics (2008), 489

Context: TW Hya is a classical T Tauri star that shows significant radial-velocity variations in the optical regime. These variations have been attributed to a 10 M_Jup planet orbiting the star at 0.04 AU ... [more ▼]

Context: TW Hya is a classical T Tauri star that shows significant radial-velocity variations in the optical regime. These variations have been attributed to a 10 M_Jup planet orbiting the star at 0.04 AU. Aims: The aim of this letter is to confirm the presence of the giant planet around TW Hya by (i) testing whether the observed RV variations can be caused by stellar spots and (ii) analyzing new optical and infrared data to detect the signal of the planet companion. Methods: We fitted the RV variations of TW Hya using a cool spot model. In addition, we obtained new high-resolution optical & infrared spectra, together with optical photometry of TW Hya and compared them with previous data. Results: Our model shows that a cold spot covering 7% of the stellar surface and located at a latitude of 54° can reproduce the reported RV variations. The model also predicts a bisector semi-amplitude variation <10 m s[SUP]-1[/SUP], which is less than the errors of the RV measurements discussed in Setiawan et al. (2008, Nature, 451, 38). The analysis of our new optical RV data, with typical errors of 10 m s[SUP]-1[/SUP], shows a larger RV amplitude that varies depending on the correlation mask used. A slight correlation between the RV variation and the bisector is also observed although not at a very significant level. The infrared H-band RV curve is almost flat, showing a small variation (<35 m s[SUP]-1[/SUP]) that is not consistent with the published optical orbit. All these results support the spot scenario rather than the presence of a hot Jupiter. Finally, the photometric data shows a 20% (peak to peak) variability, which is much larger than the 4% variation expected for the modeled cool spot. The fact that the optical data are correlated with the surface of the cross-correlation function points towards hot spots as being responsible for the photometric variability. Conclusions: We conclude that the best explanation for the RV signal observed in TW Hya is the presence of a cool stellar spot and not an orbiting hot Jupiter. Based on observations taken at the VLT (Paranal), under programs 280.C-5064(A) and 075.C-0202(A), and with the CORALIE spectrograph and EulerCAM both at the Euler Swiss telescope (La Silla). [less ▲]

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See detailErratum: "the Transit Light Curve Project. VII. The Not-So Exoplanet HAT-P-1B" (2007, AJ, 134, 1707)
Winn, Joshua N; Holman, Matthew J; Bakos, Gaspar Á et al

in Astronomical Journal (The) (2008), 136

Two of the midtransit times that were given in Table 3 of Winn et al. 2007 (AJ, 134, 1707-1712) are incorrect. The first entry was incorrect because a trend in the out-of-transit flux had not been removed ... [more ▼]

Two of the midtransit times that were given in Table 3 of Winn et al. 2007 (AJ, 134, 1707-1712) are incorrect. The first entry was incorrect because a trend in the out-of-transit flux had not been removed as described in the text. The sixth entry gave an incorrect epoch, and a midtransit time that was too small by one orbital period, because of a rounding error in the computer code that generated the table. The corrected times are given below in a revised version of Table 3. With these revisions, the ephemeris parameters given in the text following Equation (4) are changed slightly, to T[SUB]c[/SUB] (0) = 2453997.79252(32) (HJD) and P = 4.46543(13) days, where the numbers in parentheses indicate the 1sigma uncertainty in the last two digits. We note that a more precise ephemeris has been calculated by Johnson et al. (2008), based on a combination of the data presented here and more recent transit observations. [less ▲]

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2008)

L'énigme magnétique solaire; V1280 Sco : la nova fumante; Spirales barrées; Galaxies en fusion; L'étoile pivoine; Fermi-GLAST; Nuages martiens; Chaînon manquant; 2006 SQ372; Rosetta près de Steins; Nuages ... [more ▼]

L'énigme magnétique solaire; V1280 Sco : la nova fumante; Spirales barrées; Galaxies en fusion; L'étoile pivoine; Fermi-GLAST; Nuages martiens; Chaînon manquant; 2006 SQ372; Rosetta près de Steins; Nuages noctiluques; Une découverte massive de XMM-Newton; [less ▲]

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See detailPoints de repère pour prévenir la maltraitance
Bullens, Quentin ULg; Debluts, Danielle; Dubois, Françoise

Learning material (2008)

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See detailA structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn1.1Fe0.9P1-xGex compounds
Sougrati, Moulay Tahar ULg; Hermann, Raphaël ULg; Grandjean, Fernande ULg et al

in Journal of Physics : Condensed Matter (2008), 20

The structural, magnetic and Mössbauer spectral properties of the magnetocaloric Mn1.1Fe0.9P1−xGex compounds, with 0.19 < x < 0.26, have been measured between 4.2 and 295 K. The 295 K unit-cell volume ... [more ▼]

The structural, magnetic and Mössbauer spectral properties of the magnetocaloric Mn1.1Fe0.9P1−xGex compounds, with 0.19 < x < 0.26, have been measured between 4.2 and 295 K. The 295 K unit-cell volume increases from x = 0.19 to 0.22 and is substantially smaller in the ferromagnetic Mn1.1Fe0.9P0.74Ge0.26. The temperature dependence of the magnetization reveals a ferromagnetic to paramagnetic transition with a Curie temperature between approximately 250 and 330 K and hysteresis width of 10 to 4 K, for 0.19 < x < 0.25. The composition Mn1.1Fe0.9P0.78Ge0.22 shows the largest isothermal entropy change of approximately 10 J/(kgKT) at 290 K. The M¨ossbauer spectra have been analysed with a binomial distribution of hyperfine fields correlated with a change in isomer shift and quadrupole shift, a distribution that results from the distribution of phosphorus and germanium among the near neighbours of the iron. The coexistence of paramagnetic and magnetically ordered phases in ranges of temperature of up to 50 K around the Curie temperature is observed in the Mössbauer spectra and is associated with the first-order character of the ferromagnetic to paramagnetic transition. The temperature dependence of the weighted average hyperfine field is well fitted within the magnetostrictive model of Bean and Rodbell. Good fits of the Mössbauer spectra could only be achieved by introducing a difference between the isomer shifts in the paramagnetic and ferromagnetic phases, a difference that is related to the magnetostriction and electronic structure change. [less ▲]

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See detailPhilosophie politique et approche pragmatique du politique en contexte islamique. Lecture d’al-Mâwardi
Nachi, Mohamed ULg

in Gandolfi et Levi, Paola et Giovani (Ed.) Entre théologie et Politique: Les origines théologiques cachées de la pensée politique contemporaine dans les pays de la Méditerranée (2008, October)

Montrer l'apport d'al-Mâwardi pour le développement d'une approche pragmatique du politique en contexte islamique

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See detailFire Performance of undamaged and pre-damaged welded steel-concrete composite beam-to-column joints with concrete filled tubes
Alderighi, Elisabetta; Bursi, Oreste; Franssen, Jean-Marc ULg et al

Conference (2008, October)

Major earthquakes in urban areas have often been followed by significant conflagrations that have been difficult to control and have resulted in extensive damage to property. Earthquakes, then, increase ... [more ▼]

Major earthquakes in urban areas have often been followed by significant conflagrations that have been difficult to control and have resulted in extensive damage to property. Earthquakes, then, increase the risk of loss of life if a fire occurs within a building. It is obvious therefore that a fire after an earthquake is a design scenario that should be properly addressed in any performance-based design, in locations where significant earthquakes can occur. In this paper both experimental and numerical results of undamaged and pre-damaged welded steel-concrete composite beam-to-column joints with concrete filled tubes are described as part of a European project aimed at developing fundamental data, design guidelines and prequalification of ductile and fire resistant composite beam-to-column joints. In detail, both the experimental program and the fire experimental results are presented and discussed in this paper together with thermal numerical simulations on frames and joints. Both the experimental activity and the numerical work demonstrated the adequacy of the seismic and joint fire design. [less ▲]

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See detailFractionation process to produce a new milk ingredient enriched in phospholipids and sphingolipids
Bodson, P.; Dalemans, D.; Danthine, Sabine ULg et al

Poster (2008, October)

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See detailULG FACULTE D'ARCHITECTURE (ex LAMBERT LOMBARD ).SITE BOTANIQUEISA
Frisenna, Marina ULg

in PROVINCE DE LIEGE-CULTURE (Ed.) BIENNALE INTERNATIONALE -DESIGN LIEGE 2008 (2008)

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See detailDes chiffres et des Lettres
Habrand, Tanguy ULg

Article for general public (2008)

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See detailUnderwater Imagery, a Measuring Tool to Extend the Spatio-Temporal Understanding of Benthic Organisms Dynamics: Case Study of Codium elisabethae in the Azores.
Sirjacobs, Damien ULg; Tempera, Fernando; Cardigos, Frederico et al

Poster (2008, October)

Benthic habitat mapping studies have been increasingly exploiting the use of underwater images to collect information on substrate nature and biological coverage. Concurrently, research has been ongoing ... [more ▼]

Benthic habitat mapping studies have been increasingly exploiting the use of underwater images to collect information on substrate nature and biological coverage. Concurrently, research has been ongoing to develop methods that use the imagery collected to conduct regular quantitative monitoring studies of biological resources distributed over large areas. This study provides the first multi-annual monitoring information on the dynamics of a benthic macroalgae population derived from underwater imagery collected by scuba divers in the Monte da Guia Site of Community Importance /Natura 2000 network (Faial isl. Azores, NE Atlantic). The green alga Codium elisabethae - a long-living green alga that represents a potential good indicator of coastal environmental change - was chosen for the study. The analyses focus on using the underwater imagery to quantify seasonal fluctuations of density, percentage cover, biomass, growth rate and primary production of the species. Two study sites were investigated: one was located in a sheltered no-go reserve exhibiting a dense C. elisabethae population, and the other in a location experiencing more exposed conditions and holding a sparser population. Between August 2003 and November 2005, fifteen (15) photo coverages were collected by scuba-divers. Subsequent processing consisted of producing image mosaics and using automated and interactive change detection methods that recognized, measured and counted individuals present in photos of fixed quadrats and yielded dynamical parameters such as population structures, growth, recruitment, and mortality. Chi-square tests of image-derived estimates and in situ measurements confirmed the validity of a centimeter precision estimation of population structure for individuals above 4 cm diameter. Important variability of population structure and density were observed at small spatial scales. Population density showed a sharp reduction in autumn 2003 and did not show a full recovery in spring and summer 2004. During the following year, population of the protected site maintained density and biomass, while at the exposed site population density dropped. The production of information based on observations of thousands of individuals is mandatory in biological population statistics. The presented imagery approach made it possible, avoiding the need to collect all the measurements and quantitative information during time-constrained SCUBA diving operations. [less ▲]

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See detailHolographic techniques at long wave infrared wavelengths
Vandenrijt, Jean-François ULg; Georges, Marc ULg

in Proceedings of the International Symposium to Commemorate the 60th Anniversary of the Invention of Holography (2008, October)

For industrial applications, holographic interferometry and electronic speckle pattern interferometry techniques using visible laser light are often too sensitive to external perturbations. Consequently ... [more ▼]

For industrial applications, holographic interferometry and electronic speckle pattern interferometry techniques using visible laser light are often too sensitive to external perturbations. Consequently they require too much stability, preventing their widespread use in field applications. One simple idea to overcome this problem is to increase the wavelength of the laser light. We considered the 10 µm wavelength range corresponding to well known CO2 laser and because imagers exist in this spectral range. One other important advantage is that the strain/displacement measurement range is larger than the equivalent techniques in visible light. We will present the preliminary experiences performed so far with components available in our lab. Mainly, we show in-plane electronic speckle pattern interferometry and for the first time digital holographic interferometry. We also discuss specific problems related to the wavelength increase. [less ▲]

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See detailHolographic interferometry with photorefractive crystals : recent industrial applications
Thizy, Cédric ULg; Georges, Marc ULg; Hustinx, Guy-Michel et al

in Proceedings of the International Symposium to Commemorate the 60th Anniversary of the Invention of Holography (2008, October)

Photorefractive crystals allow in-situ dynamic holographic recording and indefinite reusability. Also they exhibit specific properties that other recording materials do not and which can be advantageously ... [more ▼]

Photorefractive crystals allow in-situ dynamic holographic recording and indefinite reusability. Also they exhibit specific properties that other recording materials do not and which can be advantageously used in holographic interferometry. For 15 years we have been developing holographic interferometry techniques and devices with Bi12SiO20 (BSO) crystals. The dynamic behaviour of the latter allows a high degree of userfriendliness of holographic interferometry (like techniques based on electronic recording), together with higher resolution interferograms (no speckle noise - no need of filtering). In the past we already have presented a wide range of applications in metrology, NDT and vibrations measurement. Here we present recent industrial applications obtained with a device which is now commercially available. It has proven successful applications in highly demanding applications where high resolution was required [less ▲]

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See detailRole of photorefractive holographic interferometry in Impact Assessment Procedure applied to movable cultural heritage
Thizy, Cédric ULg; De Rauw, Dominique ULg; Georges, Marc ULg et al

in Proceedings of the International Symposium to Commemorate the 60th Anniversary of the Invention of Holography (2008, October)

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See detailPerspectives politiques et stratégiques autour de la ligne Bruxelles – Luxembourg avant la guerre franco-allemande de 1870
Bechet, Christophe ULg

in Bulletin Trimestriel de l'Institut Archéologique du Luxembourg Arlon (2008), (3/4),

Les tractations dont le réseau ferroviaire luxembourgeois a fait l’objet depuis la construction de ses premières lignes dans les années 1850 jusqu’à la veille de la Première Guerre mondiale constituent un ... [more ▼]

Les tractations dont le réseau ferroviaire luxembourgeois a fait l’objet depuis la construction de ses premières lignes dans les années 1850 jusqu’à la veille de la Première Guerre mondiale constituent un sac de noeuds diplomatiques et financiers particulièrement complexe, eu égard à l’importance géopolitique de cette région coincée entre la France et la Prusse, région autour de laquelle s’exprimeront à plusieurs reprises au cours du XIXe siècle les rivalités politiques, économiques et militaires de ces deux grandes puissances. L’objectif de cet article n’est pas tant de démêler en détail ces « noeuds », qui ont présidé à l’histoire du réseau luxembourgeois, car même synthétisés à l’extrême, un article n’y suffirait pas. Nous nous proposons plutôt, à la manière d’un homme d’Etat ou d’un officier penché sur sa carte d’Etat-major, d’analyser les conséquences politiques, économiques et militaires directes ayant accompagné, dans les années 1850 et 1860, le projet puis l’achèvement en 1858/1859 de la ligne Bruxelles – Arlon – Luxembourg. Cette analyse s’inscrit dans le cadre d’une thèse de doctorat que nous menons à l’Université de Liège sur la géographie militaire de la Belgique (1839-1914) consistant à recueillir un maximum de témoignages de militaires, de diplomates et de publicistes belges et étrangers sur l’importance stratégique de notre territoire. [less ▲]

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See detailLa répression du négationnisme en Belgique : de la réussite législative au blocage politique
Grandjean, Geoffrey ULg

Conference (2008, October)

This study focuses on the prosecution of genocide-denial in Belgium and on the current deadlock of this political question. A political science approach is used to shed light on this issue which makes ... [more ▼]

This study focuses on the prosecution of genocide-denial in Belgium and on the current deadlock of this political question. A political science approach is used to shed light on this issue which makes often the headlines. The study is based on the analysis of parliamentary documents and on several interviews with the key actors of this issue. This approach enables an analytic understanding of this question. The research topic is all the more meaningful because it concerns dialectics between the present and the past and it puts into questions the place of history in politics. [less ▲]

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See detailPotential use of Paracentrotus lividus as bioindicator for recent trace element pollution monitoring
Richir, Jonathan ULg; Gobert, Sylvie ULg; Bouquegneau, Jean-Marie ULg

Poster (2008, October)

The Mediterranean Sea is an enclosed basin, highly submitted to anthropogenic pressures. Chemical pollution originating from coastal urban centres and industries, or carried by air and rivers, will ... [more ▼]

The Mediterranean Sea is an enclosed basin, highly submitted to anthropogenic pressures. Chemical pollution originating from coastal urban centres and industries, or carried by air and rivers, will primarily affect its coastal ecosystems. The pollution by trace elements into the marine environment is rapidly evolving further to the recent modifications of their production and industrial uses by men. As a result, some trace elements that were previously poorly studied can be considered now as environmental pollutants, whose concentrations can sometimes be way above their natural baseline levels. The purple sea urchin Paracentrotus lividus is a well know bioindicator used for metal pollution monitoring (Fe, Cd, Cr, Pb, Zn and Cu) along the Mediterranean and Atlantic coasts. This sedentary organism successfully concentrates the pollutants diluted in its environment, and the measured concentrations reflect properly the health status of the ecosystem. This study is a first approach on the use of P. lividus as bioindicator for some less investigated trace elements (Al, V, Mn, Co, Ni, Se, Mo and Ag), chosen for their potential toxic effects. We have compared the element concentrations of the digestive tract tissues and gonads of female and male sea urchins. The organisms were frozen prior to dissection, or they were dissected alive, the two experimental procedures being compared afterwards. The existence of an eventual relationship between their gonadic index or their test diameter and the measured pollutant concentrations was also investigated. [less ▲]

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See detailNote sur l’expertise en sémiotique
Badir, Sémir ULg

E-print/Working paper (2008)

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