164 research outputs found
Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal
Strong gravitational lensing gives access to the total mass distribution of
galaxies. It can unveil a great deal of information about the lenses dark
matter content when combined with the study of the lenses light profile.
However, gravitational lensing galaxies, by definition, appear surrounded by
point-like and diffuse lensed signal that is irrelevant to the lens flux.
Therefore, the observer is most often restricted to studying the innermost
portions of the galaxy, where classical fitting methods show some
instabilities. We aim at subtracting that lensed signal and at characterising
some lenses light profile by computing their shape parameters. Our objective is
to evaluate the total integrated flux in an aperture the size of the Einstein
ring in order to obtain a robust estimate of the quantity of ordinary matter in
each system. We are expanding the work we started in a previous paper that
consisted in subtracting point-like lensed images and in independently
measuring each shape parameter. We improve it by designing a subtraction of the
diffuse lensed signal, based only on one simple hypothesis of symmetry. This
extra step improves our study of the shape parameters and we refine it even
more by upgrading our half-light radius measurement. We also calculate the
impact of our specific image processing on the error bars. The diffuse lensed
signal subtraction makes it possible to study a larger portion of relevant
galactic flux, as the radius of the fitting region increases by on average
17\%. We retrieve new half-light radii values that are on average 11\% smaller
than in our previous work, although the uncertainties overlap in most cases.
This shows that not taking the diffuse lensed signal into account may lead to a
significant overestimate of the half-light radius. We are also able to measure
the flux within the Einstein radius and to compute secure error bars to all of
our results
Projet « HRS4R – Research Data Management » : Faciliter la gestion ouverte et responsable des données de la recherche
Ce rapport concerne le projet “HRS4R - Research Data Management”, qui s'est déroulé de janvier 2021 à février 2022. Son objectif principal était de renforcer le soutien aux chercheurs en gestion responsable des données de la recherche. Soutenu par la Fédération Wallonie-Bruxelles, ce travail s’est déroulé suivant trois axes : la guidance, la sensibilisation et la formation des chercheurs. Les six universités de la FWB ont opéré en consortium pour formaliser les rôles de Research Data Officier et développer des outils et services favorisant l’application des principes FAIR et la traçabilité des données scientifiques. L’approche interuniversitaire a permis de créer un cadre structurant pour la gestion des données de recherche en FWB et d’apporter une véritable plus-value au projet, notamment en permettant à tous de profiter de l’avancement de chacun, en centralisant et en accélérant les initiatives.HRS4R - Research Data Managemen
Joigning forces: building a community of data ambassadors across universities in Brussels-wallonia federation (Belgium)
Over the last decades, research has become more digital, collaborative and open. Research openness has extended from articles to other research outputs, including datasets. Meanwhile, datasets are growing bigger and are requiring more financial and energy investments. In addition, the reproducibility crisis has highlighted the need for a cultural change in research data management, which most funding agencies are nudging by requiring compliance to the FAIR data principles. Institutions can help researchers address this new pressure through support from cross-disciplinary staff and librarians, and by implementing general data management tools. This basic and necessary initiative from universities most often translates into awareness campaigns and general training sessions that often end up overbooked, highlighting the growing interest of researchers in these issues. However, this central approach lacks the discipline-specific expertise needed to properly translate the general recommendations into actionable items. With most institutions being decentralised across many campuses, logic pushes towards relying on local relays. Inspired by their peers from Cambridge and TUDelft, the six universities in the Brussels-Wallonia Federation (FWB, Belgium) have launched, as a consortium, a community of Data Ambassadors (DAs). Sometimes called Data Champions, DAs are researchers acting as local experts who bring awareness in their immediate work environment (department, research unit…) towards data management best practices. DA networks have the advantage of automatically addressing another weakness of central support, that is, the lack of resources, by capitalizing on existing workforce with the relevant expertise. While lean in terms of spending, this approach does however point towards the issues of resources availability for such services. On top of these benefits, DA networks enable peer-to-peer support, which has been shown to be a much more efficient drive towards change than top-down initiatives. The FWB consortium hopes to strengthen links between research groups across universities and disciplines. The aim is to empower individual researchers and engage whole communities to be better data managers, instead of trying to command change from a hierarchic point of view. Launched in December 2021, the DA community has already received massive interest with over 60 members enrolled over the first couple of weeks. Although inspired by other institutions, this network presents the specificity of being an entirely bottom-up initiative, without any other existing catalysing interuniversity structure, thus facing the challenge of building its own tools from the ground up. The following paper introduces the launching process - based upon the TUDelft model, and it reports on the overall experience from pioneering DAs, including their achievements and difficulties. The vision for settling and expanding the network and its expected successes and challenges are presented
The immediate effects of two manual therapy techniques on ankle musculoarticular stiffness and dorsiflexion range of motion in people with chronic ankle rigidity: A randomized clinical trial
OBJECTIVE: Ankle rigidity is a common musculoskeletal disorder affecting the talocrural joint, which can impair weight-bearing ankle dorsiflexion (WBADF) and daily-life in people with or without history of ankle injuries. Our objective was to compare the immediate effects of efficacy of Mulligan Mobilization with Movement (MWM) and Osteopathic Mobilization (OM) for improving ankle dorsiflexion range of motion (ROM) and musculoarticular stiffness (MAS) in people with chronic ankle dorsiflexion rigidity. DESIGN: A randomized clinical trial with two arms. METHODS: Patients were recruited by word of mouth and via social network as well as posters, and analyzed in the neuro musculoskeletal laboratory of the “Université Catholique de Louvain-la-Neuve”, Brussels, Belgium. PARTICIPANTS: 67 men (aged 18–40 years) presenting with potential chronic non-specific and unilateral ankle mobility deficit during WBDF were assessed for eligibility and finally 40 men were included and randomly allocated to single session of either MWM or OM. INTERVENTIONS: Two modalities of manual therapy indicated for hypothetic immediate effects in chronic ankle dorsiflexion stiffness, i.e. MWM and OM, were applied during a single session on included patients. MAIN OUTCOME MEASURES: Comprised blinding measures of MAS with a specific electromechanical device (namely: Lehmann’s device) producing passive oscillatory ankle joint dorsiflexion and with clinical measures of WBADF-ROM as well. RESULTS: A two-way ANOVA revealed a non-significant interaction between both techniques and time for all outcome measures. For measures of MAS: elastic-stiffness (p= 0.37), viscous-stiffness (p= 0.83), total-stiffness (p= 0.58). For WBADF-ROM: toe-wall distance (p= 0.58) and angular ROM (p= 0.68). Small effect sizes between groups were determined with Cohen’s d ranging from 0.05 to 0.29. One-way ANOVA demonstrated non-significant difference and small to moderate effects sizes (d= 0.003–0.58) on all outcome measures before and after interventions within both groups. A second two-way ANOVA analyzed the effect of each intervention on the sample categorized according to injury history status, and demonstrated a significant interaction between groups and time only for viscous stiffness (p= 0.04, d=-0.55). CONCLUSION: A single session of MWM and OM targeting the talocrural joint failed to immediately improve all measures in subjects with chronic ankle dorsiflexion stiffness. Despite this, there was an increase in viscous stiffness in people with history of ankle injury following both manual techniques, the value of which remains unclear even if it might help to prevent future abnormal ankle joint movements
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