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Peer Reviewed
See detailAssessment of benefits of joint use of multiple medical imaging modalities: case of 3D neuroimaging
Vigneron, Lara M.; Verly, Jacques ULg

Conference (2002, June)

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See detailAssessment of bioinformatic pipelines for the analysis of 454 pyrosequencing data using artificial cyanobacterial communities
Stelmach Pessi, Igor ULg; De Carvalho Maalouf, Pedro; Laughinghouse IV, Haywood ULg et al

Poster (2013, November 27)

The field of microbial ecology has undergone a revolution with the advent of next-generation sequencing (NGS) technologies, which revealed a higher microbial diversity than what was previously observed ... [more ▼]

The field of microbial ecology has undergone a revolution with the advent of next-generation sequencing (NGS) technologies, which revealed a higher microbial diversity than what was previously observed. The possibility of analyzing tens to hundreds of thousands sequences in a single sequencing run has provided information on rare taxa that could constitute an important fraction of microbial communities. However, this comes with the cost of relatively high error rates for individual reads, which can lead to overestimation of diversity due to the generation of spurious Operational Taxonomic Units (OTUs) consisting of erroneous sequences. Therefore, a correct assessment of microbial diversity using NGS relies on robust bioinformatic tools in order to correct for PCR and sequencing biases. Here we report on community structures recovered for two artificial cyanobacterial communities applying three commonly used and two recently published bioinformatic pipelines. This pilot study was made in the frame of the BELSPO project CCAMBIO. Artificial communities were constructed using DNA isolated from 22 cyanobacterial strains from the BCCM/ULC Polar Cyanobacteria Collection (http://bccm.belspo.be/about/ulc.php). DNA was extracted from individual cultures and pooled at equal (community Art1) or tiered (community Art2) concentrations. The V3-V4 hypervariable region of the 16S rRNA gene was amplified by PCR using primers 359F and 781Ra/781Rb [Nübel et al (1997) Appl Environ Microbiol 63: 3327-3332], and amplicons were sequenced on a 454 GS FLX Titanium platform. Data was demultiplexed and submitted to five bioinformatic pipelines for quality control of reads, removal of chimeric sequences and Operational Taxonomic Units (OTUs) clustering: (I) “shhh.flows (450 flows)”, (II) “shhh.flows (360-720 flows)” and (III) “Sliding Window (Q35, 50 bp)”, using MOTHUR according to Schloss et al (2011) [Schloss et al (2011) PLOS One 6: e27310]; (IV) “fastq_maxee” and (V) “fastq_truncqual”, using UPARSE according to Edgar (2013) [Edgar (2013) Nat Methods 10: 996-998]. Average sequence length varied considerably among pipelines, with pipeline I generating shorter reads (220 bp in average) and pipelines IV and V longer reads (370 bp). The number of OTUs obtained in each pipeline also varied significantly. While 22 and 21 OTUs were obtained for pipelines IV and V, respectively, pipelines I-III generated a surprisingly high number of OTUs (199, 317 and 289, respectively). Despite differences in the number of OTUs, the relative abundance of each reference strain did not differ significantly between pipelines. Overall, community structures observed using the UPARSE protocol (pipelines IV and V) were the most consistent with the expected results. These findings show the importance of assessing the performance of different bioinformatic pipelines using artificial communities, in order to reduce the effects of PCR and sequencing errors, which can lead to distorted community structures estimates. [less ▲]

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See detailAssessment of bovine tuberculosis risk factors based on nationwide molecular epidemiology
Humblet, Marie-France ULg; Gilbert, M.; Govaerts, M. et al

in Journal of Clinical Microbiology (2010)

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See detailAssessment of changes in soil organic matter after invasion by exotic plant species
Koutika, Lydie*-Stella; Vanderhoeven, SONIA ULg; Chapuis-Lardy, Lydie et al

in Biology & Fertility of Soils (2007), 44(2), 331-341

Invasive exotic plants can modify soil organic matter (SOM) dynamics and other soil properties. We evaluated changes in particulate organic matter (POM) and carbon (C) mineralisation in adjacent plots ... [more ▼]

Invasive exotic plants can modify soil organic matter (SOM) dynamics and other soil properties. We evaluated changes in particulate organic matter (POM) and carbon (C) mineralisation in adjacent plots invaded by Solidago gigantea, Prunus serotina, Heracleum mantegazzianum and Fallopia japonica, and non-invaded control plots on different soils in Belgium. Litter decomposition of S. gigantea and P. serotina was compared to that of the native species Epilobium hirsutum, Betula pendula and Fagus sylvatica. Disregarding the differences in site characteristics (soil texture, parental material and plant species), we argued that the invasion by S. gigantea and P. serotina enhance SOM dynamics by increasing C mineralisation in 2 out of 3 sites invaded by S. gigantea and in 1 out of 3 sites invaded by P. serotina; C in coarse POM (cPOM, 4,000-250 mu m) and fine POM (fPOM, 250-50 mu m) in 1 site invaded by S. gigantea and C content in total POM (tPOM, 4,000-50 mu m) and the organo-mineral fraction (OMF, 0-50 mu m) in 1 site invaded by P. serotina. H. mantegazzianum and F. japonica slowed down SOM dynamics by reducing C mineralisation in three out of four sites; C and nitrogen (N) of fPOM in the invaded compared with the non-invaded plots at one site invaded by H. mantegazzianum. However, N content of cPOM (4,000-250 mu m) was higher in the invaded sites by F. japonica compared with the non-invaded plots. Our results indicated that the effects of invasion by exotic plant species were not species-specific but site-specific. [less ▲]

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See detailAssessment of Complex Perineal Fistulas
Bruyninx, Luc ULg; Meunier, Paul ULg

in Acta Chirurgica Belgica (2000), 100(3, May-Jun), 115-7

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See detailAssessment of conceptual model uncertainty for the regional aquifer Pampa del Tamarugal – North Chile
Rojas, Rodrigo; Batelaan, Okke; Feyen, Luk et al

in Hydrology & Earth System Sciences (2010), 14

In this work we assess the uncertainty in modelling the groundwater flow for the Pampa del Tamarugal Aquifer (PTA) – North Chile using a novel and fully integrated multimodel approach aimed at explicitly ... [more ▼]

In this work we assess the uncertainty in modelling the groundwater flow for the Pampa del Tamarugal Aquifer (PTA) – North Chile using a novel and fully integrated multimodel approach aimed at explicitly accounting for uncertainties arising from the definition of alternative conceptual models. The approach integrates the Generalized Likelihood Uncertainty Estimation (GLUE) and Bayesian Model Averaging (BMA) methods. For each member of an ensemble M of potential conceptualizations, model weights used in BMA for multi-model aggregation are obtained from GLUE-based likelihood values. These model weights are based on model performance, thus, reflecting how well a conceptualization reproduces an observed dataset D. GLUE-based cumulative predictive distributions for each member of M are then aggregated obtaining predictive distributions accounting for conceptual model uncertainties. For the PTA we propose an ensemble of eight alternative conceptualizations covering all major features of groundwater flow models independently developed in past studies and including two recharge mechanisms which have been source of debate for several years. Results showed that accounting for heterogeneities in the hydraulic conductivity field (a) reduced the uncertainty in the estimations of parameters and state variables, and (b) increased the corresponding model weights used for multi-model aggregation. This was more noticeable when the hydraulic conductivity field was conditioned on available hydraulic conductivity measurements. Contribution of conceptual model uncertainty to the predictive uncertainty varied between 6% and 64% for ground water head estimations and between 16% and 79% for ground water flow estimations. These results clearly illustrate the relevance of conceptual model uncertainty. [less ▲]

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See detailAssessment of consciousness with electrophysiological and neurological imaging techniques.
Bruno, Marie-Aurélie ULg; Gosseries, Olivia ULg; Ledoux, Didier ULg et al

in Current Opinion in Critical Care (2011)

PURPOSE OF REVIEW: Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with ... [more ▼]

PURPOSE OF REVIEW: Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with disorders of consciousness encountered after coma such as the 'vegetative' or minimally conscious states. RECENT FINDINGS: Increasing evidence from functional neuroimaging and electrophysiology demonstrates some residual cognitive processing in a subgroup of patients who clinically fail to show any response to commands, leading to the recent proposal of 'unresponsive wakefulness syndrome' as an alternative name for patients previously coined 'vegetative' or 'apallic'. SUMMARY: Consciousness can be viewed as the emergent property of the collective behavior of widespread thalamocortical frontoparietal network connectivity. Data from physiological, pharmacological and pathological alterations of consciousness provide evidence in favor of this hypothesis. Increasing our understanding of the neural correlates of consciousness is helping clinicians to do a better job in terms of diagnosis, prognosis and finally treatment and drug development for these severely brain-damaged patients. The current challenge remains to continue translating this research from the bench to the bedside. Only well controlled large multicentric neuroimaging and electrophysiology studies will enable to identify which paraclinical diagnostic or prognostic test is necessary for our routine evidence-based assessment of individuals with disorders of consciousness. [less ▲]

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See detailAssessment of crop based farming systems with a focus on pigeonpea in one selected district in arid and semi-arid lands in the Kenyan coast. Ed. by E. Feoli, D. Pottier, Z. Woldu. Sustainable development of dryland areas of East Africa
Mwang'Ombe, A.W; Olubayo, F; Baudoin, Jean-Pierre ULg et al

in Proceedings of the International Workshop, Addis Ababa, November 9th-12th 1998. European Commission (2000)

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See detailAn assessment of cross-listed firms’ diversification potential
Mouchette, Xavier ULg; Muller, Aline ULg

E-print/Working paper (2014)

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See detailAssessment of detection thresholds of metal oxide sensors based e-nose to the pollution emitted by odorous sources.
Nicolas, Jacques ULg; Romain, Anne-Claude ULg

in Proceedings of the Ninth international symposium on olfaction and electronic nose ISOEN'02 (2002, September)

The paper describes a method to assess the global concentration level of a complex odorous gas mixture which is detected by an electronic nose, and consequently to assess the detection threshold of the ... [more ▼]

The paper describes a method to assess the global concentration level of a complex odorous gas mixture which is detected by an electronic nose, and consequently to assess the detection threshold of the instrument for that particular odour. The studied case is the odour generated by urban waste composting facilities. The measurement is performed in the lab with an array of 12 tin oxide gas sensors on samples collected near the emission. The selected method consists in finding an equivalence between the response of each individual sensor to the concentrations of ethanol used as a standard gas and the responses to various dilution of the original sample. The main issues of that procedure are the order of magnitude of the "concentration" of the non-diluted compost emission sample expressed in ethanol-equivalent and the detection threshold of the sensor array for the compost gas. The latter result requires a suitable definition of the detection threshold, based on the signal to noise ratio. The conclusion is that the detection threshold of Tagushi sensors, expressed in equivalent-ethanol, is generally lower than 1 ppmv and is just slightly higher than the perception threshold of the human nose for the odour gener-ated by compost. [less ▲]

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See detailAssessment of determinants for osteoporosis in elderly men.
Scholtissen, Sophie ULg; Guillemin, F.; Bruyère, Olivier ULg et al

in Osteoporosis International (2009), 20(7), 1157-66

SUMMARY: The aim of this cross-sectional study was to determine and quantify some determinants associated to low bone mineral density (BMD) in elderly men. This study showed that ageing, a lower body mass ... [more ▼]

SUMMARY: The aim of this cross-sectional study was to determine and quantify some determinants associated to low bone mineral density (BMD) in elderly men. This study showed that ageing, a lower body mass index (BMI), a higher blood level of C-terminal cross-linking telopeptides of type I collagen (CTX-1), family history of osteoporosis, and/or fracture and prior fracture were associated with bone mineral density. INTRODUCTION: Our aims were to identify some determinants associated to low bone mineral density in men and to develop a simple algorithm to predict osteoporosis. METHODS: A sample of 1,004 men aged 60 years and older was recruited. Biometrical, serological, clinical, and lifestyle determinants were collected. Univariate, multivariate, and logistic regression analyses were performed. Receiver operating characteristic analysis was used to assess the discriminant performance of the algorithm. RESULTS: In the multiple regression analysis, only age, BMI, CTX-1, and family history of osteoporosis and/or fracture were able to predict the femoral neck T-score. When running the procedure with the total hip T-score, prior fracture also appeared to be significant. With the lumbar spine T-score, only age, BMI, and CTX-1 were retained. The best algorithm was based on age, BMI, family history, and CTX-1. A cut-off point of 0.25 yielded a sensibility of 78%, a specificity of 59% with an area under the curve of 0.73 in the development and validation cohorts. CONCLUSION: Ageing, a lower BMI, higher CTX-1, family history, and prior fracture were associated with T-score. Our algorithm is a simple approach to identify men at risk for osteoporosis. [less ▲]

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See detailAssessment of developmental outcome of preterm babies
Battisti, Oreste ULg

in Archives de Pédiatrie (1998), 5

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See detailAssessment of disease activity in rheumatoid arthritis with F-18-FDG PET
Beckers, Catherine ULg; Ribbens, Clio ULg; Andre, Béatrice ULg et al

in Journal of Nuclear Medicine (2004), 45(6), 956-964

The aim of this study was to assess synovitis by F-18-FDG PET in an individual joint analysis and in a global analysis of rheumatoid arthritis (RA) disease activity and to compare F-18-FDG PET parameters ... [more ▼]

The aim of this study was to assess synovitis by F-18-FDG PET in an individual joint analysis and in a global analysis of rheumatoid arthritis (RA) disease activity and to compare F-18-FDG PET parameters with clinical, biologic, and sonographic (US) rheumatoid parameters. Methods: Three hundred fifty-six joints were assessed in 21 patients with active RA: the knees in all subjects and either wrists as well as metacarpophalangeal and proximal interphalangeal joints in 13 patients, or ankles and the first metatarsophalangeal joints in the remaining 8 patients. PET analysis consisted of a visual identification of F-18-FDG uptake in the synovium and measurements of standardized uptake values (SUVs). Independent assessors performed the clinical and US examinations. Results: PET positivity was found in 63% of joints, whereas 75%, 79%, and 56% were positive for swelling, tenderness, and US analysis, respectively. Both the rate of PET-positive joints and the SUV increased with the number of positive parameters present (swelling, tenderness, US positivity) and with the synovial thickness. The mean SUV was significantly higher in joints where a power Doppler signal was found. In a global PET analysis, the number of PET-positive joints and the cumulative SUV were significantly correlated with the swollen and tender joint counts, the patient and physician global assessments, the erythrocyte sedimentation rate and C-reactive protein serum levels, the disease activity score and the simplified disease activity index, the number of US-positive joints, and the cumulative synovial thickness. Conclusion: F-18-FDG PET is a unique imaging technique that can assess the metabolic activity of synovitis and measure the disease activity in RA. [less ▲]

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See detailAssessment of ease of use and experience of the new paediatric triple-chamber bag for parenteral nutrition for preterm infants
Rigo, J; Marlowe, ML; Bonnot, D et al

in Intensive Care Medicine (2011), 37(S2), 396

Detailed reference viewed: 10 (0 ULg)