Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailOn-sky performance of the QACITS pointing control technique with the Keck/NIRC2 vortex coronagraph
Huby, Elsa ULg; Bottom, Michael; Femenia, Bruno et al

in Astronomy and Astrophysics (2017), 600

A vortex coronagraph is now available for high contrast observations with the Keck/NIRC2 instrument at L band. Reaching the optimal performance of the coronagraph requires fine control of the wavefront ... [more ▼]

A vortex coronagraph is now available for high contrast observations with the Keck/NIRC2 instrument at L band. Reaching the optimal performance of the coronagraph requires fine control of the wavefront incident on the phase mask. In particular, centering errors can lead to significant stellar light leakage that degrades the contrast performance and prevents the observation of faint planetary companions around the observed stars. It is thus critical to correct for the possible slow drift of the star image from the phase mask center, generally due to mechanical flexures induced by temperature and/or gravity field variation, or to misalignment between the optics that rotate in pupil tracking mode. A control loop based on the QACITS algorithm for the vortex coronagraph has thus been developed and deployed for the Keck/NIRC2 instrument. This algorithm executes the entire observing sequence, including the calibration steps, initial centering of the star on the vortex center and stabilisation during the acquisition of science frames. On-sky data show that the QACITS control loop stabilizes the position of the star image down to 2.4 mas rms at a frequency of about 0.02 Hz. However, the accuracy of the estimator is probably limited by a systematic error due to a misalignment of the Lyot stop with respect to the entrance pupil, estimated to be on the order of 4.5 mas. A method to reduce the amplitude of this bias down to 1 mas is proposed. The QACITS control loop has been successfully implemented and provides a robust method to center and stabilize the star image on the vortex mask. In addition, QACITS ensures a repeatable pointing quality and significantly improves the observing efficiency compared to manual operations. It is now routinely used for vortex coronagraph observations at Keck/NIRC2, providing contrast and angular resolution capabilities suited for exoplanet and disk imaging. [less ▲]

Detailed reference viewed: 41 (7 ULg)
Peer Reviewed
See detailThe Borders of Nord-Pas-de-Calais: Camps, Actors and Insecurity
Da Silva, Amanda Carolina ULg

E-print/Working paper (2017)

I explore the securitization of the immigration process developed between France and the UK as units of the EU regional security complex. My main intention was to not only identify how both countries ... [more ▼]

I explore the securitization of the immigration process developed between France and the UK as units of the EU regional security complex. My main intention was to not only identify how both countries securitized immigration together, but also to identify the social consequences its produces for the city of Calais. The FR-UK immigration policy has been implemented in the city of Calais since 2002, and over time security apparatus has become more sophisticated, which sums up the transposition of the UK border and construction of refugee camps and jungles. As a result of this process, it was possible to identify the appearance of self-established camps, emergence of new actors, and rise of nationalism. I aim to highlight the relevance of bilateral policies developed between both countries and its impacts in Calais. From this, policies’ and migrants’ representations of emerging camps, new actors and nationalism will produce considerable changes in the city. [less ▲]

Detailed reference viewed: 12 (1 ULg)
Full Text
See detailGovernance of plant health and management of crop diversity - the case of common bean health management among members of the association Croqueurs de Carottes
Klaedtke, Stephanie ULg

Doctoral thesis (2017)

All over the globe, networks of seed growers are cultivating crop diversity in fields and gardens. Their contribution to the maintenance of this diversity has been studied, but research has widely left ... [more ▼]

All over the globe, networks of seed growers are cultivating crop diversity in fields and gardens. Their contribution to the maintenance of this diversity has been studied, but research has widely left aside their management of plant health. The governance of bean health practiced by an association of artisanal seed companies, Croqueurs de Carottes, is approached as a case study in the objective of specifying how management of crop diversity and governance of plant health are articulated. Their concern for the governance of bean health is elucidated from an agroecological perspective, taking an interdisciplinary and transformative approach. Actor-network theory constitutes the backbone of the thesis, situated between agronomy and sociology and drawing upon a threefold research device: on-farm experiments, semi-directive interviews and participant observation. The Croqueurs' approach to bean health is described as in situ approach, in which plant populations are considered healthy if they are able to live with potential plant pathogens and adapt to their growing environments. Relying on ecological interactions, competences of plant health management are distributed throughout the production system. Both for plant health and crop diversity management, a seed lot is determined by a complex system of interactions. A clear boundary distinguishing plant populations from their growing environment cannot be drawn. This implies (i) that plant health must be judged upon in situ in the plants' growing environment and (ii) that the governance of plant health must be considered at the collective scale. [less ▲]

Detailed reference viewed: 105 (11 ULg)
See detailL'interdiction du port du voile au travail
Kéfer, Fabienne ULg

Scientific conference (2017, March 28)

Séminaire faisant suite aux arrêts de la CJUE du 17 mars 2017 (C.J.U.E., 14 mars 2017, G4S Secure Solutions, C-157/15 ; C.J.U.E., 14 mars 2017, Micropole Univers, C-188/15)

Detailed reference viewed: 31 (0 ULg)
Full Text
See detailQuelle place pour l'usager dans la stratégie globale de l'entreprise ?
Elsen, Catherine ULg

Conference given outside the academic context (2017)

L'intervention aborde les différentes approches centrées usagers possibles et leur mise en oeuvre en contexte entrepreneurial. La présentation fait particulièrement état de la posture et méthodologie du ... [more ▼]

L'intervention aborde les différentes approches centrées usagers possibles et leur mise en oeuvre en contexte entrepreneurial. La présentation fait particulièrement état de la posture et méthodologie du Design Thinking et en présente les principaux aspects. [less ▲]

Detailed reference viewed: 29 (3 ULg)
See detail"À propos d'une tentative de réparation symbolique envers les morts, à l'usage des vivants." Retour sur Rwanda. À travers nous l'humanité
Jousten, Lison ULg

Scientific conference (2017, March 27)

L’intervention revient sur Rwanda. À travers nous l’humanité (2006), un documentaire de Marie-France Collard inscrit dans le prolongement du spectacle Rwanda 94 (2000), auquel elle avait collaboré en tant ... [more ▼]

L’intervention revient sur Rwanda. À travers nous l’humanité (2006), un documentaire de Marie-France Collard inscrit dans le prolongement du spectacle Rwanda 94 (2000), auquel elle avait collaboré en tant qu’auteur et vidéaste. Son documentaire s’intéresse à la réception du spectacle par le public rwandais et dépeint un pays en crise, dix ans après le génocide. Entre Rwanda 94 et Rwanda. À travers nous l’humanité s’opère une série de glissements, de prolongements et d’empreintes. [less ▲]

Detailed reference viewed: 25 (0 ULg)
Full Text
Peer Reviewed
See detailFrom Loose to Boxed Fragments and Back Again. Seriality and Archive in Chris Ware's ‘Building Stories’
Crucifix, Benoît ULg

in Journal of Graphic Novels and Comics (2017)

This article focuses on the dynamics of seriality, archive and collection in Chris Ware's graphic novel “Building Stories”. It argues that the dispersed serialization of “Building Stories” is key to ... [more ▼]

This article focuses on the dynamics of seriality, archive and collection in Chris Ware's graphic novel “Building Stories”. It argues that the dispersed serialization of “Building Stories” is key to understand its box-of- comics format as well as its fragmented narrative structure. In a self-reflexive homage to the material history of comics, Ware's graphic novel indeed appears as an archive of its own serialization, foregrounding a process of collecting/dispersing fragments. [less ▲]

Detailed reference viewed: 58 (30 ULg)
See detailXenogeneic graft-versus-host disease : Impact of Th17 cells
Delens, Loïc ULg; SERVAIS, Sophie ULg; Vrancken, Louise ULg et al

Poster (2017, March 27)

Detailed reference viewed: 24 (7 ULg)
See detailLa Lumière ne sert pas qu’à voir ! Effet non-visuel de la lumière chez des personnes voyantes et non voyantes
Vandewalle, Gilles ULg

Conference given outside the academic context (2017)

Detailed reference viewed: 32 (1 ULg)
Full Text
Peer Reviewed
See detailA Markov Chain Monte Carlo Cellular Automata Model to Simulate Urban Growth
El Saeid Mustafa, Ahmed Mohamed ULg; Nishida, Gen; Saadi, Ismaïl ULg et al

in GEOProcessing 2017 proceedings, The Ninth International Conference on Advanced Geographic Information Systems, Applications, and Services (2017, March 25)

This paper investigates the potential of a cellular automata (CA) model based on logistic regression (logit) and Markov Chain Monte Carlo (MCMC) to simulate the dynamics of urban growth. The model ... [more ▼]

This paper investigates the potential of a cellular automata (CA) model based on logistic regression (logit) and Markov Chain Monte Carlo (MCMC) to simulate the dynamics of urban growth. The model assesses urbanization likelihood based on (i) a set of urban development driving forces (calibrated based on logit) and (ii) the land-use of neighboring cells (calibrated based on MCMC). An innovative feature of this CA model is the incorporation of MCMC to automatically calibrate the CA neighborhood transition rules. The MCMC based CA model is applied to Wallonia region (Belgium) to simulate urban growth from 1990 to 2000 using Corine Land Cover data (CLC). The outcome of logit model is evaluated by the relative operating characteristic (ROC). The simulated map of 2000 is then validated against 2000 actual map based on cell-to-cell location agreement. The model outcomes are realistic and relatively accurate confirming the effectiveness of the proposed MCMC-CA approach. [less ▲]

Detailed reference viewed: 38 (2 ULg)
Peer Reviewed
See detailBelgian heterosexuals’ attitudes towards different types of same-sex parenting
Scali, Thérèse ULg; D'Amore, Salvatore; Green, Robert-Jay

Conference (2017, March 25)

The legal situation of Belgian gay men and lesbians may be perceived as one of the best in Europe. Indeed, the Belgian Parliament has legalized marriage and parenting for same-sex couples, has enacted ... [more ▼]

The legal situation of Belgian gay men and lesbians may be perceived as one of the best in Europe. Indeed, the Belgian Parliament has legalized marriage and parenting for same-sex couples, has enacted anti-discrimination laws, and has funded several action plans to combat homophobia. More particularly, the access to parenthood is legally possible for same-sex couples through adoption, artificial insemination and in vitro fecundation. In this supportive political context, lots of same-sex-headed families exist. However, same-sex parenting is still considered as a controversial topic by some heterosexual people. Therefore, this paper aims at understanding heterosexuals’ attitudes towards the different types of same-sex parenting as well as the rationales underlying those attitudes. In Study 1, the degrees of support of 1168 heterosexual participants aged from 18 to 81 towards those types of parenting have been analysed through a self-report questionnaire. Results revealed that heterosexuals’ participants do not show the same degree of support towards the different types of same-sex parenting. In particular, adoption by lesbian and gay couples is the more accepted type of parenting, followed by artificial insemination. Then, adoption for single lesbians or gay men and surrogacy are the types of parenting that are the less supported. Then, though the content analysis of comments posted on social networks (Study 2), we highlighted the arguments in favour and against those specific types of parenting. Those results highlight that citizens’ attitudes can go from supportive to unsupportive and this could lead to some kind of discrimination towards children raised in specific forms of same-sex-headed families. This contribution highlights work’s implication for public policy and social transformation by understanding the challenges that gay and lesbian couples and their children have to face. [less ▲]

Detailed reference viewed: 36 (2 ULg)
See detailHistoire et images. Une épistémologie historienne du visuel : le cas d'Arlette Farge
Servais, Amandine ULg

Conference (2017, March 25)

Dans cet exposé, j'analyse le cas Montjean, inscrit au cœur de la pratique fargienne. Il m’intéresse particulièrement : il est révélateur tant du projet d’Arlette Farge que de sa mise en œuvre. Une ... [more ▼]

Dans cet exposé, j'analyse le cas Montjean, inscrit au cœur de la pratique fargienne. Il m’intéresse particulièrement : il est révélateur tant du projet d’Arlette Farge que de sa mise en œuvre. Une première fois appréhendé au sein d’un ouvrage – La vie fragile (Paris, Hachette, 1986) – qui annonce, en bien des lieux, la poétique de l’historienne, on le retrouve dans une étude récente qui, selon moi, condense – tout en légèreté – les outils de l’atelier fargien. J’estime, en effet, que La révolte de Mme Montjean (Paris, Albin Michel, 2016) est une sorte de manifeste qui, évidemment, ne se donne pas explicitement comme tel. Mais en la parcourant, librement, chapitre par chapitre, je montrerai que les fondamentaux de la pratique d’Arlette Farge – telle que je tente de la formaliser par le biais du paradigme visuel – y sont formulés. [less ▲]

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailInfectious diseases diagnosis and vaccination in pet rabbits : an everyday challenge
Marlier, Didier ULg

in Marlier, Didier (Ed.) Proceedings of the Third International Conference on Avian heRpetological and Exotic mammal medicine (2017, March 25)

Detailed reference viewed: 8 (2 ULg)
See detailN2O dynamics in sea ice, insights from a first time series and isotopic tools
Kotovitch, Marie ULg; Tison, Jean-Louis; Fripiat, François et al

Conference (2017, March 25)

Nitrous oxide (N2O) is a potent greenhouse gases that has a lifetime of 114 years in the atmosphere and a global warming potential 300 time higher than that of CO2. However there are still large ... [more ▼]

Nitrous oxide (N2O) is a potent greenhouse gases that has a lifetime of 114 years in the atmosphere and a global warming potential 300 time higher than that of CO2. However there are still large uncertainties and gaps in the understanding of the N2O cycle in polar oceans and particularly associated to sea ice. Sources and sinks of N2O are therefore poorly quantified. To date, only one study by Randall et al. 2012 present N2O measurements in sea ice. They pointed out that sea ice formation and melt has the potential to generate sea-air or air-sea fluxes of N2O, respectively. The main processes (except the transport processes) involved in the N2O cycle within the aquatic environment are nitrification and denitrification. Recent observations of significant nitrification in Antarctic sea ice shed a new light on nitrogen cycle within sea ice. It has been suggested that nitrification supplies up to 70% of nitrate assimilated within Antarctic spring sea ice. Corollary, production of N2O, a by-product of nitrification, can potentially be significant. Our recent studies in Antarctic land fast ice in McMurdo Sound, confirmed this suggestion, where N2O release to the atmosphere was estimated to reach 4 µmol.m-2.yr-1. But this assessment is probably an underestimation since it only accounts for dissolved N2O while a significant amount of N2O is likely to occur in the gaseous form like N2, O2 and Ar. We will then address the new tools to measure the bulk concentration of N2O (dissolved and gaseous) in sea ice, and the production of N2O by sympagic microorganisms - what process is dominant and how much N2O is produced - based on the first time series of N2O measurement in sea ice. The determination of the isotopic composition of N2O using cavity enhanced laser absorption spectroscopy technique (Off-axis ICOS) will allow us to determine the origin of these processes. [less ▲]

Detailed reference viewed: 25 (5 ULg)
Full Text
Peer Reviewed
See detailAn Affective Account of Distance Estimation Biases
Dumitru, Magdalena ULg

Conference (2017, March 25)

Dumitru and Joergensen (2016) employed a task designed to probe social attitudes to covertly investigate the magnitude estimation of digit-word expressions (e.g., ‘8 ants’). Here we employed a task ... [more ▼]

Dumitru and Joergensen (2016) employed a task designed to probe social attitudes to covertly investigate the magnitude estimation of digit-word expressions (e.g., ‘8 ants’). Here we employed a task designed to elicit affective states to gain insights into distance underestimation and boundary extension biases. [less ▲]

Detailed reference viewed: 13 (2 ULg)