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See detailWASP-20b and WASP-28b: a hot Saturn and a hot Jupiter in near-aligned orbits around solar-type stars
Anderson, D. R.; Collier Cameron, A.; Hellier, C. et al

E-print/Working paper (2014)

We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R ... [more ▼]

We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R_{\rm Jup}$) in a 4.9-day, near-aligned ($\lambda = 8.1 \pm 3.6^\circ$) orbit around CD-24 102 ($V$=10.7; F9). WASP-28b is an inflated, Jupiter-mass planet (0.91 $M_{\rm Jup}$; 1.21 $R_{\rm Jup}$) in a 3.4-day, near-aligned ($\lambda = 8 \pm 18^\circ$) orbit around a $V$=12, F8 star. As intermediate-mass planets in short orbits around aged, cool stars ($7^{+2}_{-1}$ Gyr for WASP-20 and $5^{+3}_{-2}$ Gyr for WASP-28; both with $T_{\rm eff}$ < 6250 K), their orbital alignment is consistent with the hypothesis that close-in giant planets are scattered into eccentric orbits with random alignments, which are then circularised and aligned with their stars' spins via tidal dissipation. [less ▲]

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See detailA multi-method approach to radial-velocity measurement for single-object spectra
David, M.; Blomme, R.; Frémat, Y. et al

in Astronomy and Astrophysics (2014), 562

Context. The derivation of radial velocities from large numbers of spectra that typically result from survey work, requires automation. However, except for the classical cases of slowly rotating late-type ... [more ▼]

Context. The derivation of radial velocities from large numbers of spectra that typically result from survey work, requires automation. However, except for the classical cases of slowly rotating late-type spectra, existing methods of measuring Doppler shifts require fine-tuning to avoid a loss of accuracy due to the idiosyncrasies of individual spectra. The radial velocity spectrometer (RVS) on the Gaia mission, which will start operating very soon, prompted a new attempt at creating a measurement pipeline to handle a wide variety of spectral types. <BR /> Aims: The present paper describes the theoretical background on which this software is based. However, apart from the assumption that only synthetic templates are used, we do not rely on any of the characteristics of this instrument, so our results should be relevant for most telescope-detector combinations. <BR /> Methods: We propose an approach based on the simultaneous use of several alternative measurement methods, each having its own merits and drawbacks, and conveying the spectral information in a different way, leading to different values for the measurement. A comparison or a combination of the various results either leads to a "best estimate" or indicates to the user that the observed spectrum is problematic and should be analysed manually. <BR /> Results: We selected three methods and analysed the relationships and differences between them from a unified point of view; with each method an appropriate estimator for the individual random error is chosen. We also develop a procedure for tackling the problem of template mismatch in a systematic way. Furthermore, we propose several tests for studying and comparing the performance of the various methods as a function of the atmospheric parameters of the observed objects. Finally, we describe a procedure for obtaining a knowledge-based combination of the various Doppler-shift measurements. [less ▲]

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See detailAlignment in star-debris disc systems seen by Herschel
Greaves, J. S.; Kennedy, G. M.; Thureau, N. et al

in Monthly Notices of the Royal Astronomical Society : Letters (2014), 438

Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral ... [more ▼]

Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral types A-M where the stellar inclination is known and can be compared to that of the spatially resolved dust belts. The discs are found to be well aligned with the stellar equators, as in the case of the Sun's Kuiper belt, and unlike many close-in planets seen in transit surveys. The ensemble of stars here can be fitted with a star-disc tilt of ≲ 10°. These results suggest that proposed mechanisms for tilting the star or disc in fact operate rarely. A few systems also host imaged planets, whose orbits at tens of au are aligned with the debris discs, contrary to what might be expected in models where external perturbers induce tilts. [less ▲]

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See detailArchéologies de l'abstraction. Sur quelques récentes en philosophie des sciences
Cavazzini, Andrea ULg

Scientific conference (2014, February 01)

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See detailCoMBiSpeC: A novel approach in the modelling of massive binaries
Palate, Matthieu ULg

in EAS Publications Series (2014, February 01)

Spectral modelling and especially for massive stars is not a straightforward problem and over the past decades many advances have been made in this field. We now have sophisticated model atmosphere codes ... [more ▼]

Spectral modelling and especially for massive stars is not a straightforward problem and over the past decades many advances have been made in this field. We now have sophisticated model atmosphere codes that allow to derive the stellar parameters. However, these codes are based on the assumption that the star is single and spherical which is no longer valid for the components of a binary system. On the other hand, observational studies indicate that binarity has an impact on the spectra. This is why we have developed a model called CoMBiSpeC (code of massive binary spectral computation) that specifically accounts for the impact of binarity on the spectra. [less ▲]

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See detailOù en est la recherche sur les dysphasies ?
Maillart, Christelle ULg

Conference given outside the academic context (2014)

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See detailA New Method for the Determination of Cyanide Ions and Their Quantification in Some Senegalese Cassava Varieties
Diallo, Younoussa; Gueye, Momar Talla; Ndiaye, Cheikh et al

in American Journal of Analytical Chemistry (2014), 5(3), 181-187

Cassava (Manihot esculenta Crantz) is a starchy staple food that previous researches have showed to contain cyanogenic compounds, precursors of hydrocyanic acid, undoubtedly toxic for humans. With the aim ... [more ▼]

Cassava (Manihot esculenta Crantz) is a starchy staple food that previous researches have showed to contain cyanogenic compounds, precursors of hydrocyanic acid, undoubtedly toxic for humans. With the aim to determine food security in cassava, this study developed a simple, fast and less expensive step for quantifying cyanide ions by using micro-diffusion with modified Conway cells. After an enzymatic degradation, the cyanide ions were quantified by electrochemical procedures. The validation of this method is estimated. The concentration of cyanide ions at different part of the samples was determined. The results showed high toxicity in some fresh Senegalese consumed cassava varieties (>100 mg HCN·kg﹣1). However, in the processed cassava products, less than 10 mg HCN·kg﹣1 was found in the different varieties studied except for the chips where the levels of CN﹣ contents were important (>49 mg HCN·kg﹣1). [less ▲]

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See detailSuspicion de fibrose pulmonaire idiopathique chez un West Highland White Terrier
Roels, Elodie ULg; Bolen, Géraldine ULg; Clercx, Cécile ULg

in Monde Vétérinaire (Le) : European Veterinary Magazine (2014), 139

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See detailMicroorganisms living on macroalgae: diversity, interactions, and biotechnological applications
Martin, Marjolaine ULg; Portetelle, Daniel ULg; Michel, Gurvan et al

in Applied Microbiology & Biotechnology (2014)

Marine microorganisms play key roles in every marine ecological process, hence the growing interest in studying their populations and functions. Microbial communities on algae remain underexplored ... [more ▼]

Marine microorganisms play key roles in every marine ecological process, hence the growing interest in studying their populations and functions. Microbial communities on algae remain underexplored, however, despite their huge biodiversity and the fact that they differ markedly from those living freely in seawater. The study of this microbiota and of its relationships with algal hosts should provide crucial information for ecological investigations on algae and aquatic ecosystems. Furthermore, because these microorganisms interact with algae in multiple, complex ways, they constitute an interesting source of novel bioactive compounds with biotechnological potential, such as dehalogenases, antimicrobials, and alga-specific polysaccharidases (e.g., agarases, carrageenases, and alginate lyases). Here, to demonstrate the huge potential of alga-associated organisms and their metabolites in developing future biotechnological applications, we first describe the immense diversity and density of these microbial biofilms. We further describe their complex interactions with algae, leading to the production of specific bioactive compounds and hydrolytic enzymes of biotechnological interest. We end with a glance at their potential use in medical and industrial applications. [less ▲]

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See detailLa validité des procédures conventionnelles de récusation d’arbitres
Caprasse, Olivier ULg; Henry, Frédéric ULg

in Journal des Tribunaux (2014)

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See detailINFLUENCE OF JUMPING STRATEGY ON KINETIC PARAMETERS
Jidovtseff, Boris ULg; Quievre, Jacques; Harris Nigel et al

in Journal of sports medicine and physical fitness (2014), 54

Aim: Different jumping strategies can be used during plyometric training. Understanding how manipulating variables such as the counter-movement, flexion amplitude, the drop and the load could influence ... [more ▼]

Aim: Different jumping strategies can be used during plyometric training. Understanding how manipulating variables such as the counter-movement, flexion amplitude, the drop and the load could influence neuromuscular adaptation would be beneficial for coaches and athletes. The purpose of this study was to analyze how these variations in the vertical jump influenced kinematic and kinetic parameters as measured by a force platform. Methods: Ten male subjects performed, eight kinds of vertical jumps on a force platform : (1) squat jump (SJ); (2) shallow counter-movement jump (S-CMJ); (3) natural counter-movement jump (N-CMJ); (4) deep counter-movement jump (D-CMJ); (5) loaded (20kg) counter-movement jump (20-CMJ); (6) shallow drop jump (S-DJ); (7) deep drop jump (D-DJ); (8) six consecutive jump test (6CJ). Customised Labview software was used to calculate time, displacement, velocity, acceleration, force, power, impulse and stiffness. After statistical analysis, jumping variables were grouped to achieve spécific training objectives. Results: The mechanical parameters were largely influenced by the jump strategy, all the deep jumps produced superior jump heights and concentric velocities as compared to the shallow jumps. The exercises associated with greater power outputs were the S-DJ (5386±1095w) and 6CJ (5795±1365w) that involved short impulse durations and very high accelerations. The greatest values of muscle stiffness were not recorded during the highest vertical jumps, meaning that stiffness is not critical for jumping high. Conclusion: This study gives an overview of what is changing when we manipulate jumping variables and instructions given to the athletes. Plyometric exercises should be carefully selected according to the sport and specific individual needs. [less ▲]

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See detailDo Photobiont Switch and Cephalodia Emancipation Act as Evolutionary Drivers in the Lichen Symbiosis? A Case Study in the Pannariaceae (Peltigerales)
Magain, Nicolas ULg; Sérusiaux, Emmanuël ULg

in PLoS ONE (2014), 9(2), 89876

Lichen symbioses in the Pannariaceae associate an ascomycete and either cyanobacteria alone (usually Nostoc; bipartite thalli) or green algae and cyanobacteria (cyanobacteria being located in dedicated ... [more ▼]

Lichen symbioses in the Pannariaceae associate an ascomycete and either cyanobacteria alone (usually Nostoc; bipartite thalli) or green algae and cyanobacteria (cyanobacteria being located in dedicated structures called cephalodia; tripartite thalli) as photosynthetic partners (photobionts). In bipartite thalli, cyanobacteria can either be restricted to a well-delimited layer within the thallus (‘pannarioid’ thalli) or spread over the thallus that becomes gelatinous when wet (‘collematoid’ thalli). We studied the collematoid genera Kroswia and Physma and an undescribed tripartite species along with representatives of the pannarioid genera Fuscopannaria, Pannaria and Parmeliella. Molecular inferences from 4 loci for the fungus and 1 locus for the photobiont and statistical analyses within a phylogenetic framework support the following: (a) several switches from pannarioid to collematoid thalli occured and are correlated with photobiont switches; the collematoid genus Kroswia is nested within the pannarioid genus Fuscopannaria and the collematoid genus Physma is sister to the pannarioid Parmeliella mariana group; (b) Nostoc associated with collematoid thalli in the Pannariaceae are related to that of the Collemataceae (which contains only collematoid thalli), and never associated with pannarioid thalli; Nostoc associated with pannarioid thalli also associate in other families with similar morphology; (c) ancestors of several lineages in the Pannariaceae developed tripartite thalli, bipartite thalli probably resulting from cephalodia emancipation from tripartite thalli which eventually evolved and diverged, as suggested by the same Nostoc present in the collematoid genus Physma and in the cephalodia of a closely related tripartite species; Photobiont switches and cephalodia emancipation followed by divergence are thus suspected to act as evolutionary drivers in the family Pannariaceae. [less ▲]

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See detailNew alternatives to chemical pesticides: deciphering the action mechanisms of lipid based plant elicitors via complementary biophysical and biological approaches.
Nasir, Mehmet Nail ULg; Polo Lozano, Damien ULg; Luzuriaga Loaiza, Walter ULg et al

Poster (2014, February)

Nowadays, many health and environmental problems are caused by the use of chemical pesticides. In this context, an increasing demand for alternative products such as biopesticides has been observed. Among ... [more ▼]

Nowadays, many health and environmental problems are caused by the use of chemical pesticides. In this context, an increasing demand for alternative products such as biopesticides has been observed. Among biopesticides, elicitor molecules which are able to trigger immune defense responses in plants are one of the most promising options. Although numerous elicitors have been discovered, the mechanisms involved in the perception, by plants, of only a few molecules have been identified. These elicitors usually interact with proteic receptors but we have recently shown that they may also act on the lipid phase of the plasma membrane. This project first aims to improve our understanding of the molecular mechanisms involved in the recognition of specific lipid based elicitors (LBE). On that basis, the FIELD project will contribute to the design and the development of innovative compounds derived natural LBE. A multi-disciplinary approach, based on chemistry, bio-physics, bio-chemistry, and phytopathology will be followed by a consortium of different research groups from Gembloux Agro-Bio Tech in close collaboration with teams from foreign institutions. [less ▲]

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See detailExploration on structure activity relation of natural, self-assembling cyclic lipodepsipeptides
Geudens, Niels; Feher, Kristina; De Vleeschouwer, Matthias et al

Poster (2014, February)

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See detailTargeting the synovial angiogenesis as a novel treatment approach to osteoarthritis.
Henrotin, Yves ULg; Pesesse, Laurence; Lambert, Cécile ULg

in Therapeutic Advances in Musculoskeletal Disease (2014), 6(1), 20-34

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See detailGuide de la rédaction du mémoire
Grandjean, Geoffrey ULg

Learning material (2014)

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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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See detailOrigin and Pulsation of Hot Subdwarfs
Randall, Suzanna K; Fontaine, Gilles; Charpinet, Stéphane et al

in Proceedings of the International Astronomical Union (2014, February), 301

We briefly introduce hot subdwarfs and their evolutionary status before discussing the different types of known pulsators in more detail. Currently, at least six apparently distinct types of variable are ... [more ▼]

We briefly introduce hot subdwarfs and their evolutionary status before discussing the different types of known pulsators in more detail. Currently, at least six apparently distinct types of variable are known among hot subdwarfs, encompassing p- as well as g-mode pulsators and objects in the Galactic field as well as in globular clusters. Most of the oscillations detected can be explained in terms of an iron opacity mechanism, and quantitative asteroseismology has been very successful for some of the pulsators. In addition to helping constrain possible evolutionary scenarios, studies focussing on stellar pulsations have also been used to infer planets and characterize the rotation of the host star. [less ▲]

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See detailThe role of protein modifications in senescence of freeze-dried Acetobacter senegalensis during storage
Shafiei, Rasoul ULg; Zarmehrkhorshid, Raziyeh ULg; Bentaib, Azeddine ULg et al

in Microbial Cell Factories (2014)

Background Loss of viability is one of the most important problems during starter culture production. Previous research has mostly focused on the production process of bacterial starters, but there are ... [more ▼]

Background Loss of viability is one of the most important problems during starter culture production. Previous research has mostly focused on the production process of bacterial starters, but there are few studies about cellular protein deterioration causing cell defectiveness during storage. In the present study, we investigated the influence of storage temperature (−21, 4, 35°C) on the cellular protein modifications which may contribute to the senescence of freeze-dried Acetobacter senegalensis. Results Heterogeneous populations composed of culturable cells, viable but non-culturable cells (VBNC) and dead cells were generated when freeze-dried cells were kept at −21 and 4°C for 12 months whereas higher storage temperature (35°C) mainly caused death of the cells. The analysis of stored cell proteome by 2D-DiGE demonstrated a modified pattern of protein profile for cell kept at 4 and 35°C due to the formation of protein spot trains and shift of Isoelectric point (pI). Quantification of carbonylated protein by ELISA showed that the cells stored at 4 and 35°C had higher carbonylated protein contents than fresh cells. 2D-DiGE followed by Western blotting also confirmed the carbonylation of cellular proteins involved in translation process and energy generation. The auto-fluorescent feature of cells kept at 35°C increased significantly which may be an indication of protein glycation during storage. In addition, the percentage of cellular unsaturated fatty acid and the solubility of cellular proteins decreased upon storage of cells at higher temperature suggesting that peroxidation of fatty acids and possibly protein lipidation and oxidation occurred. Conclusions High storage temperature induces some deteriorative reactions such as protein oxidation, lipidation and glycation which may cause further protein modifications like pI-shift, and protein insolubility. These modifications can partly account for the changes in cell viability. It can also be deduced that even moderate carbonylation of some critical cellular proteins (like ribosomal proteins) may lead to VBNC formation or death of freeze-dried bacteria. Moreover, it seems that other mechanisms of biomolecule deterioration preceding protein carbonylation lead to VBNC formation under very low storage temperature. [less ▲]

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