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See detailCdk1 is a critical mediator of ischemic/hypoxic neuronal death
Vandenbosch, Renaud ULg

Conference (2016, June 20)

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See detailNovel Methods for the Detection of Functional Brain Activity using 17O MRI
Möllenhoff, Klaus ULg

Doctoral thesis (2016)

Detailed quantitative information about metabolic processes plays a crucial role in the potential cure and for treatment of many diseases such as Alzheimer’s disease or brain tumours. In the last decades ... [more ▼]

Detailed quantitative information about metabolic processes plays a crucial role in the potential cure and for treatment of many diseases such as Alzheimer’s disease or brain tumours. In the last decades, radioactive tracers such as 15O have been used to quantify CMRO2 with PET imaging and this is regarded as the gold standard. However, such methods are complicated and expensive as a consequence of the short half-life (2 min) of 15O and inherently include radiation exposure and invasive measurements such as blood probes to probe cerebral blood flow (CBF). Fick’s principle of arteriovenous oxygen difference [1] connects CMRO2 and CBF via the measure of oxygen extraction fraction (OEF). The main goal of this work is to achieve non-invasive measures of OEF based on magnetic resonance imaging (MRI) to quantify CMRO2 allowing straightforward and comfortable patient handling. MRI enables studies of large cohorts of healthy volunteers due to noninvasive measurements and a lack of radioactivity. This can be achieved first by quantitative relaxation time mapping of the transverse relaxation time (T2) of venous blood only in proton (1H) MRI or by a measurement following inhalation of 17O gas and recording the signal curve of directly detected 17O signal. Unfortunately, the most abundant isotope of oxygen (16O) has a zero spin system, and cannot be detected with NMR experiments. In contrast, 17O, a stable isotope with a half-integer spin (I=5/2), can be detected by MR. Fortuitously, however, in MRI it is only visible in the form of metabolically generated H17 2 O and not as a gas. The low natural abundance of 17O, of only 0.037% (of the oxygen atoms) and the low NMR sensitivity (2.9% that of 1H) gives rise to the need for ultra-high-field MRI to reach a significant SNR per unit time. Natural abundance images of a healthy male volunteer were acquired in vivo after having gained written consent within a clinical trial of a 9.4T MRI system (Siemens AG, Erlangen, Germany) [2, 3]. These natural abundance images, which reflect the 17O bound to protons as H17 2 O and thus, the amount of water, are compared to 1H-based quantitative water content imaging. For further studies, the voxelwise knowledge of the quantitative water content is necessary to quantify CMRO2 based on the 17O signal behaviour. To achieve that, methods which were originally used on 1.5T scanners had to be adapted for the use at higher field strengths to overcome RF field inhomogeneities [4–11]. New correction methods were developed based on a well known correlation between tissue T1 and proton density (PD) to estimate the receive bias field properly. These methods were tested for quantitative water content determination. Averaged results in grey (GM) and white matter (WM) respectively of 10 healthy volunteers are H2OWM=70.3 1.4 %, H2OGM=84.7 1.5 %„ T1WM=918 24 ms and T1GM=1509 14 ms. Further, 1H-based imaging methods called QUIXOTIC [12–14] and TRUST [15] appeared in the literature. These methods are based on changes of the proton transverse relaxation rate T2 with different oxygen saturation levels. Quantitative values of venous blood T2 were acquired using a so-called T2prep module or a multi-echo spin echo readout. While the first method suffers from long acquisition times the latter one from large echo-spacing of the spin echoes and stimulated echo effects. Both disadvantages were overcome using an adiabatic multi-shot multi-echo spin echo sequence, which does not suffer from stimulated echo effects and due to the multi-shot capabilities, the echo-spacing is reduced [16]. Mean values in GM of four healthy volunteers are found to be venous oxygenation Yv=0.61 0.03, T2=54 4 ms, CMRO2=174 13 mol/100g min and CBF=53 3 ml/100g min. [less ▲]

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See detailMolecular Alterations and Everolimus Efficacy in Human Epidermal Growth Factor Receptor 2-Overexpressing Metastatic Breast Cancers: Combined Exploratory Biomarker Analysis From BOLERO-1 and BOLERO-3.
Andre, Fabrice; Hurvitz, Sara; Fasolo, Angelica et al

in Journal of clinical oncology : official journal of the American Society of Clinical Oncology (2016), 34(18), 2115-24

PURPOSE: Two recent phase III trials, BOLERO-1 and BOLERO-3 (Breast Cancer Trials of Oral Everolimus), evaluated the addition of everolimus to trastuzumab and chemotherapy in human epidermal growth factor ... [more ▼]

PURPOSE: Two recent phase III trials, BOLERO-1 and BOLERO-3 (Breast Cancer Trials of Oral Everolimus), evaluated the addition of everolimus to trastuzumab and chemotherapy in human epidermal growth factor receptor 2-overexpressing advanced breast cancer. The current analysis aimed to identify biomarkers to predict the clinical efficacy of everolimus treatment. METHODS: Archival tumor samples from patients in BOLERO-1 and BOLERO-3 were analyzed using next-generation sequencing, immunohistochemistry, and Sanger sequencing. RESULTS: Biomarker data were available for 549 patients. PIK3CA activating mutations and PTEN loss were reported in 30% and 16% of BOLERO-1 samples and in 32% and 12% of BOLERO-3 samples, respectively. PI3K pathway was hyperactive (PIK3CA mutations and/or PTEN loss and/or AKT1 mutation) in 47% of BOLERO-1 and 41% of BOLERO-3 samples. In both studies, differential progression-free survival (PFS) benefits of everolimus were consistently observed in patient subgroups defined by their PI3K pathway status. When analyzing combined data sets of both studies, everolimus was associated with a decreased hazard of progression in patients with PIK3CA mutations (hazard ratio [HR], 0.67; 95% CI, 0.45 to 1.00), PTEN loss (HR, 0.54; 95% CI, 0.31 to 0.96), or hyperactive PI3K pathway (HR, 0.67; 95% CI, 0.48 to 0.93). Patients with wild-type PIK3CA (HR, 1.10; 95% CI, 0.83 to 1.46), normal PTEN (HR, 1.00; 95% CI, 0.80 to 1.26), or normal PI3K pathway activity (HR, 1.19; 95% CI, 0.87 to 1.62) did not derive PFS benefit from everolimus. CONCLUSION: This analysis, although exploratory, suggests that patients with human epidermal growth factor receptor 2-positive advanced breast cancer having tumors with PIK3CA mutations, PTEN loss, or hyperactive PI3K pathway could derive PFS benefit from everolimus. [less ▲]

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See detailGreenland Ice Sheet seasonal and spatial mass variability from model simulations and GRACE (2003–2012)
Alexander, P.; Tedesco, M.; Schlegel, N-J et al

in Cryosphere (The) (2016), 10

Improving the ability of regional climate models (RCMs) and ice sheet models (ISMs) to simulate spatiotemporal variations in the mass of the Greenland Ice Sheet (GrIS) is crucial for prediction of future ... [more ▼]

Improving the ability of regional climate models (RCMs) and ice sheet models (ISMs) to simulate spatiotemporal variations in the mass of the Greenland Ice Sheet (GrIS) is crucial for prediction of future sea level rise. While several studies have examined recent trends in GrIS mass loss, studies focusing on mass variations at sub-annual and sub-basin-wide scales are still lacking. At these scales, processes responsible for mass change are less well understood and modeled, and could potentially play an important role in future GrIS mass change. Here, we examine spatiotemporal variations in mass over the GrIS derived from the Gravity Recovery and Climate Experiment (GRACE) satellites for the January 2003–December 2012 period using a "mascon" approach, with a nominal spatial resolution of 100 km, and a temporal resolution of 10 days. We compare GRACE-estimated mass variations against those simulated by the Modèle Atmosphérique Régionale (MAR) RCM and the Ice Sheet System Model (ISSM). In order to properly compare spatial and temporal variations in GrIS mass from GRACE with model outputs, we find it necessary to spatially and temporally filter model results to reproduce leakage of mass inherent in the GRACE solution. Both modeled and satellite-derived results point to a decline (of −178.9 ± 4.4 and −239.4 ± 7.7 Gt yr−1 respectively) in GrIS mass over the period examined, but the models appear to underestimate the rate of mass loss, especially in areas below 2000 m in elevation, where the majority of recent GrIS mass loss is occurring. On an ice-sheet-wide scale, the timing of the modeled seasonal cycle of cumulative mass (driven by summer mass loss) agrees with the GRACE-derived seasonal cycle, within limits of uncertainty from the GRACE solution. However, on sub-ice-sheet-wide scales, some areas exhibit significant differences in the timing of peaks in the annual cycle of mass change. At these scales, model biases, or processes not accounted for by models related to ice dynamics or hydrology, may lead to the observed differences. This highlights the need for further evaluation of modeled processes at regional and seasonal scales, and further study of ice sheet processes not accounted for, such as the role of subglacial hydrology in variations in glacial flow. [less ▲]

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See detailORCmKit: an open-source library for organic Rankine cycle modelling and analysis
Dickes, Rémi ULg; Ziviani, Davide; van den Broek, Martjin et al

in Proceedings of ECOS 2016 (2016, June 20)

As for many other technologies, modelling and simulation of organic Rankine cycles (ORCs) are crucial for design, optimization and control purposes. However, model development is often time consuming and ... [more ▼]

As for many other technologies, modelling and simulation of organic Rankine cycles (ORCs) are crucial for design, optimization and control purposes. However, model development is often time consuming and the scientific community lacks of open-access tools to study ORC systems. For these reasons, researchers from the universities of Liège and Ghent in Belgium gathered their knowledge and created “ORC modelling Kit” (ORCmKit), an open-source library dedicated to the steady-state simulation and analysis of organic Rankine cycles. Both component-level and cycle-level models are provided and different ORC architectures can be simulated. For each of the main component of ORC systems, different models are available with increasing complexity which allows a wide range of modelling possibilities. In order to remain general and accessible to as many people as possible, three widely used programming languages are covered within ORCmKit, i.e. Matlab, Python and EES (Engineering Equation Solver). Besides source codes, ORCmKit also includes calibration tools for empirical and semi-empirical models as well as a complete documentation for ease of use. [less ▲]

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See detailPlace of customary rights mapping initiatives in conservation policies
Vermeulen, Cédric ULg; Karsenty, Alain

Conference (2016, June 20)

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See detailInfluence of frugivore taxa on the generation of plant recruitment foci and on the composition of plant recruits’ communities
Trolliet, Franck ULg; Forget, Pierre-Michel; Doucet, Jean-Louis ULg et al

Conference (2016, June 20)

Frugivores can disperse seeds in a spatially contagious pattern and generate recruitment foci (e.g. under fruiting trees). This process is increasingly explored to understand the influence of frugivores ... [more ▼]

Frugivores can disperse seeds in a spatially contagious pattern and generate recruitment foci (e.g. under fruiting trees). This process is increasingly explored to understand the influence of frugivores on the spatial organization of plant communities, and can also serve as a method to efficiently monitor the consequences of animal extirpation. However, there is limited evidence contrasting the influence of different frugivores taxa on the creation of recruitment foci under fruiting trees, and, similarly, on the overall composition of plant communities. Here, we aimed (i) to compare the role of hornbills and primates in creating recruitment foci, and (ii) to investigate how the presence of hornbills, primates and elephants influence the overall composition of plant recruit’s community in an anthropized forest-savanna mosaic in DR Congo. We firstly compared the community of recruits (0.5-2 m high) in 25-m² plots below hornbill-dispersed trees (Staudtia kamerunensis, N=32), primate-dispersed trees (Dialium spp., N=26), and in control plots located below other tree species (N= 4900 m²). Secondly, we considered all plots to compare the community of recruits in five sites characterized by contrasted levels of hunting and housing different seed disperser communities. Our preliminary results indicate (i) communities of recruits below hornbill-dispersed trees are significantly more dense and richer than in control plots, unlike these below primate-dispersed trees. Also, (ii) recruits in sites less affected by hunting, housing more large frugivores, including elephants, tend to belong to species with longer seeds. We conclude that hornbills generate recruitment foci under fruiting trees, which can serve as an efficient tool to monitor the ecological consequences of their extirpation. Moreover, we discuss the potential influence of the different studied frugivore taxa and the risk of their extirpation from afro-tropical forests on the composition of plant recruits’ community. [less ▲]

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See detailA stochastic 3-Scale approach to study the thermomechanical damping of MEMS
Wu, Ling ULg; Lucas, Vincent ULg; Nguyen, Van Dung ULg et al

Scientific conference (2016, June 20)

A stochastic 3-scale approach is developed to study the thermo-elastic quality factor (Q) of micro-electromechanical systems (MEMS) resonators. Thermo-elastic damping is one of the major dissipation ... [more ▼]

A stochastic 3-scale approach is developed to study the thermo-elastic quality factor (Q) of micro-electromechanical systems (MEMS) resonators. Thermo-elastic damping is one of the major dissipation mechanisms in high-Q micro-resonators, which may have detrimental effects on the quality factor, and has to be predicted accurately. Since material uncertainties are inherent to and unavoidable in MEMS, the effects of those variations have to be considered in the numerical models. To this end, a coupled thermo-mechanical stochastic 3-scale approach is considered. Thermo-mechanical micro-models of poly-silicon materials are used to represent micro-structure realizations. A computational stochastic homogenization procedure is then applied on these statistical volume elements to obtain the probabilistic distribution of the elasticity tensor, thermal expansion and conductivity tensors at the meso-scale. Spatially correlated meso-scale random fields are then generated in order to represent the probabilistic behavior of the homogenized material properties, feeding macro-scale stochastic finite element simulations. [less ▲]

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See detailStorytelling in Videogames: From “Narrative” Towards “Fictional Universe”
Barnabé, Fanny ULg

Conference (2016, June 18)

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See detailVisual artificial grammar learning in children with SLI : Is variability the key ?
Desmottes, Lise ULg; Maillart, Christelle ULg; Demelenne, Pauline et al

Poster (2016, June 18)

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See detail"World of Chemistry" : Gamification d'activités d'entrainement en chimie générale"
le Maire, Nathalie ULg

Scientific conference (2016, June 17)

Présentation et évaluation du potentiel de quatre mini-jeux développés dans le cours de chimie générale en Bac 1 en vue d'augmenter la fréquentation de la matière par les étudiants.

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See detailSerious Game Biotechnologie: dans la peau d'un responsable de laboratoire de diagnostic
Massart, Sébastien ULg

Scientific conference (2016, June 17)

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See detailEvaluation of Adaptive Facades: The Case Study of AGC Headquarter in Belgium
Attia, Shady ULg; Bashandy, Hamza

in Belis, Jan; Louter, Christian (Eds.) Challenging Glass 5 (2016, June 17)

The evaluation of adaptive facades presents a challenge because there is no established evaluation strategy to systematically reach this goal and many of the available façade performance evaluation tools ... [more ▼]

The evaluation of adaptive facades presents a challenge because there is no established evaluation strategy to systematically reach this goal and many of the available façade performance evaluation tools have limited applicability for such advanced building facades. This paper presents a case study for an adaptive glass façade and evaluates its performance. The evaluation focuses mainly on pre and post construction phase of adaptive facades: The design assist phase (including the durability test, visual mockup, onsite panel mounting and weather stripping), the commissioning phase (field verification and performance testing) and the monitoring phase. The selected project is a nearly zero energy building with unique façade comprising thermal isolated glass sunshades printed with white silk screen. These louvers respond dynamically and automatically to the angle of the sun which improves the control over energy consumption, solar radiation and glare with the ability to admit natural light into the building. The paper is part of the research activities of working group 3 of the European COST Action 1403 on “Adaptive Facades “. Different methods were used for evaluation, this include: interviews with the architect, façade engineer and technical control specialist, reviews of standard and codes and a systematic process mapping. A documentation of the case study describing the post construction occupant comfort and façade operation was prepared. This paper’s audience is mainly architects, building façade engineers together with facility managers concerned with the process of design, construction and operation of adaptive glass facades. The outcome of this study identifies effective strategies for the design and performance evaluation of optimal adaptive facades. [less ▲]

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See detailETUDE DE LA DYNAMIQUE DE LA DESERTIFICATION DANS LE BASSIN VERSANT DE LA MOULOUYA EN INTEGRANT LES DONNEES ISSUES DE LA TELEDETECTION ET LES DONNEES SOCIO-ECONOMIQUES
Mokhtari, Noureddine ULg

Doctoral thesis (2016)

La recherche sur la désertification et la dégradation de l’environnement est très complexe et vise la mise en relation entre les ressources de l’environnement, leurs limites de durabilité et des usages ... [more ▼]

La recherche sur la désertification et la dégradation de l’environnement est très complexe et vise la mise en relation entre les ressources de l’environnement, leurs limites de durabilité et des usages qui se font de ces ressources par l’homme en tant qu’agent économique qui vise à améliorer son bien-être. Dans le bassin versant de la Moulouya caractérisé par un climat essentiellement aride à semi-aride, une augmentation sensible de la population et une forte hausse de la demande en ressources naturelles, le problème de la désertification se pose en termes d’adaptation des besoins de la population aux contraintes du milieu en vue de maintenir la durabilité des ressources. Dans ce sens, le challenge consiste en un double objectif, premièrement l’évaluation de la désertification à travers l’analyse de l’état de dégradation du milieu et deuxièmement, l’étude des causes de cette dégradation moyennant des enquêtes axées sur les pratiques agricoles et la formulation de propositions d’actions à entreprendre pouvant être utilisés de manière opérationnelle par les acteurs locaux et les pouvoirs publics. Ainsi, le suivi de la dynamique des phénomènes biophysiques liés à la désertification s’est fait essentiellement à travers l’étude de l’évolution du climat et de la qualité de la végétation à l’échelle de l’ensemble de la zone étudiée (NDVI) et au niveau d’une zone d’intérêt pour la recherche (occupation du sol). Pour la végétation, le suivi spatio-temporel de la végétation a montré pour les trois sources de données à basse résolution utilisées (GIMMS, MEDOKADS et SPOT) des évolutions similaires de l’indice de végétation NDVI. Malgré les différences entre les amplitudes de variation du NDVI, liées essentiellement aux spécificités des algorithmes de traitement, les trois séries données conservent la même tendance stationnaire au cours du temps. D’une manière générale, les fluctuations du NDVI mises en évidence à l’aide des données NDVI à basse résolution reflètent principalement les variations spatio-temporelles en quantité et en qualité des précipitations d’une année par rapport à une autre et ne montrent aucune tendance particulière concernant la qualité de la végétation. L’identification des zones sensibles à la désertification, réalisée sur la base de l’approche MEDALUS, a montré que les zones fragiles et critiques totalisent 61% de la superficie du bassin versant, soit une superficie d’environ 3,25 millions d’Ha. Spatialement, les zones sensibles à la dégradation se trouvent aussi bien dans la Basse Moulouya que dans les Hauts Plateaux et la vallée de Missour constitués essentiellement de parcours steppiques. L’analyse de la dynamique d’occupation du sol à travers l’utilisation des images satellites (LANDSAT) pour la commune de Tissaf, choisie comme zone d’intérêt pour la recherche, a révélé une dégradation qualitative de la végétation. En effet, de grandes superficies d’Alfa dense à très dense (végétation climacique) se sont dégradées pour se retrouver dans la classe d’Alfa faiblement dense, soit une diminution de l’ordre de 16.199 Ha sur 20 ans. L’analyse des causes de la dégradation des parcours au niveau de la commune de Tissaf à travers l’étude de la productivité des parcours et du système d’élevage pastoral a révélé que le capital, en tant que facteur de production, joue un rôle important dans les stratégies d’utilisation des ressources fourragères « gratuites » issues des parcours collectifs. Ainsi, les grands éleveurs sédentaires ou semi-nomades disposant d’importants fonds propres et grâce à une utilisation plus opportuniste des parcours collectifs paraissent profiter davantage de ces ressources (46.478,15 UF) par rapport aux petits éleveurs sédentaires et transhumants (5.148,70 UF et 18.714,40 UF). Les petits éleveurs qui adaptent l’effectif de leur cheptel en fonction des conditions du milieu (décapitalisation en période de sécheresse) semblent profiter moins en quantité et en qualité des ressources pastorales disponibles. En guise de conclusion, la thèse propose des scénarios d’adaptation des systèmes de production agricoles qui peuvent être utilisés d’une manière opérationnelle par les acteurs locaux et les pouvoirs publics en vue d’orienter les stratégies de développement et d’investissement vers les secteurs rentables économiquement et qui respectent en même temps l’environnement. [less ▲]

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See detailL'exercice des tâches régaliennes en Belgique : sommes-nous un Etat structurellement vulnérable ?
Behrendt, Christian ULg

Conference given outside the academic context (2016)

Conférence donnée à Wavre, Hôtel de ville, 17 juin 2016, lors d'une réunion conjointe de mandataires du Brabant wallon et de Flandre occidentale

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See detailDévelopper du code avec une équipe de "non-geeks" à l'ULg
Boman, Romain ULg

Speech/Talk (2016)

Cette présentation a été faite aux "Geeks Anonymes" de l'Université de Liège le 17 juin 2016. J'y présente les techniques de développement de logiciels vers lesquelles notre groupe de recherche a convergé ... [more ▼]

Cette présentation a été faite aux "Geeks Anonymes" de l'Université de Liège le 17 juin 2016. J'y présente les techniques de développement de logiciels vers lesquelles notre groupe de recherche a convergé après 20 ans de pratique. En particulier, je détaille les compromis qui ont dû être trouvés pour aider les thésards et ingénieurs de recherche peu à l'aise avec l'informatique. [less ▲]

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See detailCapturing fine-level structure using unsupervised clustering method with multiple data types
Chaichoompu, Kridsadakorn ULg; Tongsima, Sissades; Shaw, Philip James et al

Poster (2016, June 17)

Several methods exist to detect shared genetic ancestry or to identify population substructure using SNP-based or haplotype-based information (Price et al. 2006, Lawson et al. 2012). Here, we propose an ... [more ▼]

Several methods exist to detect shared genetic ancestry or to identify population substructure using SNP-based or haplotype-based information (Price et al. 2006, Lawson et al. 2012). Here, we propose an unsupervised clustering method built on the ipPCA algorithm (Intarapanich et al. 2009). Our method supports both ordinal and categorical data, and it can be applied to panels of single locus and/or multiple loci data, or gene-based integrative summaries (Fouladi et al. 2015). Our method involves an iterative process using binary and ternary splits based on multivariate Gaussian mixture modeling of PCs and Clustering EM estimation as in (Lebret et al. 2015). To evaluate its performance, we examined different simulated scenarios of 2-4 populations, 500-8,000 individuals, 5,000-20,000 independent SNPs in HWE, and FST=[0.0007,0.006] (Balding and Nichols 1995), with 100 replicates for each scenario. SNPs were treated as categorical or continuous including ancestry-corrected SNPs. Haplotype-based runs used HapMap 3 data: CHB, CHD, and JPT. In simulated scenarios of extremely subtle structure (FST=[0.0009,0.006]), a population classification accuracy of 92% or greater was obtained, which was superior to ipPCA. Also in case of the HapMap populations, promising results to detect fine structure were obtained. We are convinced that our method has a potential to detect fine-level structure and it will be important in molecular reclassification studies of patients once underlying population structure has been removed. [less ▲]

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