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See detailNear infrared spectroscopy in large animals: optical pathlengh and influence of hair covering and epidemal pigmentation
Pringle, J.; Roberts, C.; Kohl, M. et al

in Veterinary Journal (1999), 158

The effects of epidermal pigmentation and hair covering on the relative transparency of various animal tissues to near infrared (NIR) light were examined, and the pathlengths of NIR light through tissues ... [more ▼]

The effects of epidermal pigmentation and hair covering on the relative transparency of various animal tissues to near infrared (NIR) light were examined, and the pathlengths of NIR light through tissues at four wavelengths in the NIR range were subsequently determined. Black hair covering and black or dark-coloured hooves prevented NIR light from penetration sufficient for conduction of pathlength or NIR spectroscopy measurements. Non-pigmented hair covering of the head did not appear to be a barrier to successful NIR light transmission. Tissues sufficiently transparent to NIR light had the differential pathlength factor (DPF, i.e. the ratio of the observed light pathlength and the geometric light source-detector separation) of NIR light determined by intensity modulated spectroscopy at the wavelengths 744, 806, 834 and 860 nm. Horse gluteal muscles had DPFs of 6.2, 6.2, 6.0, and 5.6, whereas forelimb muscles had DPF of 4.7, 4.4, 4.5 and 3.9 at the respective wavelengths. Sheep heads had DPF of 7.2 +/- 0.3, 5.8 +/- 0.5, 5.5 +/- 0.4 and 4.4 +/- 0.6 (+/- SEM) for the above respective wavelengths, of which the pathlengths all differed significantly from the other, except for between 806 and 834 nm, and 834 and 860 nm. The DPF of horse hooves were 4.8 +/- 0.1, 4.8 +/- 0.1, 4.7 +/- 0.1 and 4.4 +/- 0.1 (SEM) for the above noted wavelengths, of which the pathlength at 744 and 806 nm differed from the pathlength at 860 nm (P>0.05). These results show that NIRS is possible through lighter pigmented hair and epidermal tissues, and provide DPFs of horse feet and muscle and the sheep head that enables quantitative NIRS in these species. [less ▲]

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See detailNear Infrared Spectroscopy of the Normal Bovine Claw
Pringle, John; Uystepruyst, Christophe; Art, Tatiana ULg et al

in Veterinary Journal (1998), 156(2), 155-158

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See detailNear Optimal Closed-Loop Control. Application to Electric Power Systems
Ernst, Damien ULg

Doctoral thesis (2003)

Detailed reference viewed: 44 (17 ULg)
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See detailNear real time assessment of the ionosphere effect on high accuracy GNSS applications which require ambiguity resolution
Lejeune, Sandrine; Warnant, René ULg

in Proceedings of the 2nd COST296 Workshop (2006, October)

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See detailNear real time assessment of the Space Weather effect on navigation based on the DGPS technique
Lejeune, Sandrine; Warnant, René ULg; Barré, Aline et al

Conference (2005)

Detailed reference viewed: 9 (0 ULg)
See detailNear real-time assessment of the ionospheric effect on navigation based on DGPS corrections
Lejeune, Sandrine; Warnant, René ULg; Barré, Aline et al

in Proceedings of Beacon Satellite Symposium 2004 (2005)

Detailed reference viewed: 12 (1 ULg)
See detailNear real-time evaluation of the EGNOS ionospheric correction at mid-latitude
Bavier, Michaël; Warnant, René ULg; Barré, Aline et al

in Proceedings of Beacon Satellite Symposium 2004 (2005)

Detailed reference viewed: 20 (1 ULg)
See detailNear real-time validation of GPS-TEC using ionosonde TEC at Dourbes
Warnant, René ULg; Nebdi, Hamid; Pottiaux, Eric

Report (2003)

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See detailNear- and mid-infrared colours of star-forming galaxies in European Large Area ISO Survey fields
Vaisanen, Petri; Morel, Thierry ULg; Rowan-Robinson, M. et al

in Monthly Notices of the Royal Astronomical Society (2002), 337

We present J- and K-band near-infrared (near-IR) photometry of a sample of mid-infrared (mid-IR) sources detected by the Infrared Space Observatory (ISO) as part of the European Large Area ISO Survey ... [more ▼]

We present J- and K-band near-infrared (near-IR) photometry of a sample of mid-infrared (mid-IR) sources detected by the Infrared Space Observatory (ISO) as part of the European Large Area ISO Survey (ELAIS) and study their classification and star-forming properties. We have used the Preliminary ELAIS Catalogue for the 6.7-μm (LW2) and 15-μm (LW3) fluxes. All of the high-reliability LW2 sources and 80 per cent of the LW3 sources are identified in the near-IR survey reaching K~ 17.5 mag. The near-IR/mid-IR flux ratios can effectively be used to separate stars from galaxies in mid-IR surveys. The stars detected in our survey region are used to derive a new accurate calibration for the ELAIS ISOCAM data in both the LW2 and LW3 filters. We show that near- to mid-IR colour-colour diagrams can be used to classify galaxies further, as well as to study star formation. The ELAIS ISOCAM survey is found mostly to detect strongly star-forming late-type galaxies, possibly starburst-powered galaxies, and it also picks out obscured active galactic nuclei. The ELAIS galaxies yield an average mid-IR flux ratio LW2/LW3 = 0.67 +/- 0.27. We discuss the f[SUB]ν[/SUB](6.7 μ m)/f[SUB]ν[/SUB](15 μ m) ratio as a star formation tracer using ISO and IRAS data of a local comparison sample. We find that the f[SUB]ν[/SUB](2.2 μ m)/f[SUB]ν[/SUB](15 μ m) ratio is also a good indicator of activity level in galaxies and conclude that the drop in the f[SUB]ν[/SUB](6.7 μ m)/f[SUB]ν[/SUB](15 μ m) ratio seen in strongly star-forming galaxies is a result of both an increase of 15-μm emission and an apparent depletion of 6.7-μm emission. Near-IR together with the mid-IR data make it possible to estimate the relative amount of interstellar matter in the galaxies. [less ▲]

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See detailNear-Death Experiences : Real or imagined memories?
Thonnard, Marie ULg; Laureys, Steven ULg; Brédart, Serge ULg et al

Poster (2010, September)

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See detailNear-death experiences: real or imagined?
Thonnard, Marie ULg; Laureys, Steven ULg; Brédart, Serge ULg et al

Conference (2010, June)

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See detailNear-field coupling of wireless devices and long communications cables
Christopoulos, Christos; Zhang, Yinghong ULg; Paul, J. et al

in IET Science, Measurement & Technology (2008), 2(1), 18-24

A comprehensive investigation of the coupling between mobile devices and communication/control cables in several environments is described here. Both experimental and numerical results are shown and ... [more ▼]

A comprehensive investigation of the coupling between mobile devices and communication/control cables in several environments is described here. Both experimental and numerical results are shown and compared using a number of different methods in different laboratories. Results indicate a good level of agreement between the different approaches thus giving confidence that predictive studies based on simulation can give a good quantitative assessment of coupling. Moreover, the studies show that varying the configuration of the coupled systems does not significantly affects the maximum coupling thus making it possible to obtain a reasonable worst case estimate of coupling from a small number of generic studies. [less ▲]

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See detailNear-infrared [Fe II] emission from supernova remnants and the supernova rate of starburst galaxies
Morel, Thierry ULg; Doyon, R.; St-Louis, N.

in Monthly Notices of the Royal Astronomical Society (2002), 329

In an effort better to calibrate the supernova rate of starburst galaxies as determined from near-infrared [FeII] features, we report on a [FeII] λ1.644μm line-imaging survey of a sample of 42 optically ... [more ▼]

In an effort better to calibrate the supernova rate of starburst galaxies as determined from near-infrared [FeII] features, we report on a [FeII] λ1.644μm line-imaging survey of a sample of 42 optically selected supernova remnants (SNRs) in M33. A wide range of [FeII] luminosities are observed within our sample (from less than 6 to 695L[SUB]solar[/SUB]). Our data suggest that the bright [FeII] SNRs are entering the radiative phase and that the density of the local interstellar medium (ISM) largely controls the amount of [FeII] emission. We derive the following relation between the [FeII] λ1.644μm line luminosity of radiative SNRs and the electronic density of the post-shock gas, n[SUB]e[/SUB]: L[SUB][FeII][/SUB] (L[SUB]solar[/SUB])~1.1n[SUB]e[/SUB] (cm[SUP]-3[/SUP]). We also find a correlation in our data between L[SUB][FeII][/SUB] and the metallicity of the shock-heated gas, but the physical interpretation of this result remains inconclusive, as our data also show a correlation between the metallicity and n[SUB]e[/SUB]. The dramatically higher level of [FeII] emission from SNRs in the central regions of starburst galaxies is most likely due to their dense environments, although metallicity effects might also be important. The typical [FeII]-emitting lifetime of a SNR in the central regions of starburst galaxies is found to be of the order of 10[SUP]4[/SUP]yr. On the basis of these results, we provide a new empirical relation allowing the determination of the current supernova rate of starburst galaxies from their integrated near-infrared [FeII] luminosity. [less ▲]

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See detailNear-infrared identification of the counterpart to X1908+075: a new OB-supergiant X-ray binary
Morel, Thierry ULg; Grosdidier, Y.

in Monthly Notices of the Royal Astronomical Society (2005), 356

We report the near-infrared (near-IR) identification of the likely counterpart to X1908+075, a highly absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant-neutron ... [more ▼]

We report the near-infrared (near-IR) identification of the likely counterpart to X1908+075, a highly absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant-neutron star binary systems. Our JHK[SUB]s[/SUB]-band imaging of the field reveals the existence within the X-ray error boxes of a near-IR source consistent with an early-type star lying at d~ 7 kpc and suffering A[SUB]V[/SUB]~ 16 mag of extinction, the latter value being in good agreement with the hydrogen column density derived from modelling of the X-ray spectrum. Our follow-up, near-IR spectroscopic observations confirm the nature of this candidate and lead to a late O-type supergiant classification, thereby supporting the identification of a new Galactic OB-supergiant X-ray binary. [less ▲]

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See detailA near-infrared interferometric survey of debris disc stars. II. CHARA/FLUOR observations of six early-type dwarfs
Absil, Olivier ULg; di Folco, E.; Mérand, A. et al

in Astronomy and Astrophysics (2008), 487

Aims. We aim at directly detecting the presence of optically thin circumstellar dust emission within the terrestrial planetary zone around main sequence stars known to harbour cold debris discs. The ... [more ▼]

Aims. We aim at directly detecting the presence of optically thin circumstellar dust emission within the terrestrial planetary zone around main sequence stars known to harbour cold debris discs. The present study focuses on a sample of six bright A- and early F-type stars. Methods: High-precision interferometric observations have been obtained in the near-infrared K band with the FLUOR instrument installed on the CHARA Array. The measured squared visibilities are compared to the expected visibility of the stellar photospheres based on theoretical photospheric models taking into account rotational distortion. We search for potential visibility reduction at short baselines, a direct piece of evidence for resolved circumstellar emission. Results: Our observations bring to light the presence of resolved circumstellar emission around one of the six target stars (zeta Aql) at the 5sigma level. The morphology of the emission source cannot be directly constrained because of the sparse spatial frequency sampling of our interferometric data. Using complementary adaptive optics observations and radial velocity measurements, we find that the presence of a low-mass companion is a likely origin for the excess emission. The potential companion is characterised by a K-band contrast of four magnitudes. It has a most probable mass of about 0.6~Msun and is expected to orbit between about 5.5 AU and 8 AU from its host star assuming a purely circular orbit. Nevertheless, by adjusting a physical debris disc model to the observed Spectral Energy Distribution of the zeta Aql system, we also show that the presence of hot dust within 10 AU from zeta Aql, producing a total thermal emission equal to 1.69 ± 0.31% of the photospheric flux in the K band, is another viable explanation for the observed near-infrared excess. Our re-interpretation of archival near- to far-infrared photometric measurements shows however that cold dust is not present around zeta Aql at the sensitivity limit of the IRS and MIPS instruments onboard Spitzer, and urges us to remove zeta Aql from the category of bona fide debris disc stars. Conclusions: The hot debris disc around Vega (Absil et al. 2006) currently remains our only secure resolved detection within the context of this survey, with six genuine early-type debris disc stars observed so far. Further observations will be needed to assess whether zeta Aql also belongs to this hot debris disc category. Partly based on observations collected at the European Southern Observatory, La Silla, Chile, under program IDs 073.C-0733, 077.C-0295 and 080.C-0712. [less ▲]

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See detailA near-infrared interferometric survey of debris disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR
Absil, Olivier ULg; Defrère, Denis; Coudé du Foresto, Vincent et al

in Astronomy and Astrophysics (2013), 555

Context. Dust is expected to be ubiquitous in extrasolar planetary systems due to the dynamical activity of minor bodies. Inner dust populations are, however, still poorly known due to the high contrast ... [more ▼]

Context. Dust is expected to be ubiquitous in extrasolar planetary systems due to the dynamical activity of minor bodies. Inner dust populations are, however, still poorly known due to the high contrast and small angular separation with respect to their host star. Yet, a proper characterisation of exozodiacal dust is mandatory for the design of future Earth-like planet imaging missions. Aims. We aim to determine the level of near-infrared exozodiacal dust emission around a sample of 42 nearby main sequence stars with spectral types ranging from A to K, and to investigate its correlation with various stellar parameters and with the presence of cold dust belts. Methods. We use high-precision K-band visibilities obtained with the FLUOR interferometer on the shortest baseline of the CHARA array. The calibrated visibilities are compared with the expected visibility of the stellar photosphere to assess the presence of an additional, fully resolved circumstellar emission source. Results. Near-infrared circumstellar emission amounting to about 1% of the stellar flux is detected around 13 of our 42 target stars. Follow-up observations showed that one of them (eps Cep) is associated with a stellar companion, while another one was detected around what turned out to be a giant star (kap CrB). The remaining 11 excesses found around single main sequence stars are most probably due to the presence of hot circumstellar dust, yielding an overall occurrence rate of 28+8-6% for our (biased) sample. We show that the occurrence rate of bright exozodiacal discs correlates with spectral type, K-band excesses being more frequent around A-type stars. It also correlates with the presence of detectable far-infrared excess emission in the case of solar-type stars. Conclusions. This study provides new insights regarding the phenomenon of bright exozodiacal disc, showing that hot dust populations are probably linked to outer dust reservoirs in the case of solar-type stars. In the case of A-type stars, no clear conclusion can be made regarding the origin of the detected near-infrared excesses. [less ▲]

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