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See detailComparison of gradient-based and gradient-free methods for optimal stacking sequence of composites
Bruyneel, Michaël ULg; Colsoul, Freddie; Zein, Samih

in Proceedings of the SAMPE Technical Conference 2013 (2013, October)

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See detailA comparison of grey-box and black-box approaches in nonlinear state-space modelling and identification
Noël, Jean-Philippe ULg; Schoukens, Johan; Kerschen, Gaëtan ULg

Conference (2015, March)

In the present contribution, it is shown that, in the case of mechanical systems where nonlinearities are physically localised, the general structure of black-box nonlinear state-space models can be ... [more ▼]

In the present contribution, it is shown that, in the case of mechanical systems where nonlinearities are physically localised, the general structure of black-box nonlinear state-space models can be drastically simplified. A more parsimonious, grey-box state-space representation is derived, which is found to be compatible with Newton's second law of dynamics. For demonstration purposes, black-box and grey-box state-space models of the Silverbox benchmark, i.e. an electrical mimicry of a single-degree-of-freedom mechanical system with cubic nonlinearity, are identified using a maximum likelihood estimator. It is found that the grey-box approach allows to reduce markedly modelling errors with respect to a black-box model with a comparable number of parameters. It is also suggested that the greater accuracy of the grey-box model lends itself to the computation of reliable confidence bounds on the model parameters. [less ▲]

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See detailComparison of ground-based remote sensing and in-situ observations of CO, CH4 and O3, accounting for representativeness uncertainty
Henne, S.; Steinbacher, M.; Mahieu, Emmanuel ULg et al

Conference (2013, April)

The EC project NORS (Demonstration Network Of ground-based Remote Sensing Observations in support of the GMES Atmospheric Service) aims at demonstrating the value of ground-based remote sensing data for ... [more ▼]

The EC project NORS (Demonstration Network Of ground-based Remote Sensing Observations in support of the GMES Atmospheric Service) aims at demonstrating the value of ground-based remote sensing data for quality assessment and improvement of the GMES products. As part of NORS CO, CH4, O3 and NO2 tropospheric products as obtained by ground-based remote sensing within the Network for the Detection of Atmospheric Composition Change (NDACC) are compared to continuous surface in-situ measurements that are reported on common international reference scales within the Global Atmospheric Watch (GAW) Programme. However, a direct comparison between the different methods is hindered by different sampling volumes, introducing uncertainties due to representativeness. Here we present a novel method that utilises high-resolution, backward Lagrangian particle dispersion modelling to characterise the transport history of different sampling volumes. Sampling volumes are defined as infinitesimally small point volumes for the in-situ observations and as separate profile segments with horizontal and vertical extent for the remote sensing observations. The characterisation is then used (a) to filter times for which a direct comparison between in-situ and remote sensing data is unfavourable (large representativeness uncertainty) and (b) to construct vertical profiles from the in-situ observations, taking additional information from large scale atmospheric composition models into account. These so called “in-situ” profiles are supposed to be more comparable to the remote sensing profile as the surface value itself, while conserving the high accuracy information of the latter and projecting it onto the profile. Therefore, these profiles allow for a more direct comparison and validation of the remotely sensed profiles. The technique was first applied at two of the four NORS demonstration sites (Jungfraujoch, Switzerland and Izana, Spain) and to the comparison of remote sensing Fourier-transform infrared spectrometer (FTIR) measurements of CO, CH4, and O3 with the responding in-situ observations. While previous studies generally showed good agreement between the two kinds of observation, considerable amounts of scatter were evident. Selecting only situations with relatively small representativeness uncertainty reduces this scatter. Folding the “in-situ” profiles with the averaging kernels of the FTIR retrieval gives a more realistic comparison result that is not influenced by any a-priori assumptions. Results are also discussed with respect to season, time of day and weather type. [less ▲]

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See detailComparison of growth limits of Listeria monocytogenes in milk, broth and cheese
Jordan, Kieran; Schvartzman Echenique, Maria Sol ULg; Belessi, C et al

Conference (2010, June)

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See detailComparison of growth limits of Listeria monocytogenes in milk, broth and cheese.
Schvartzman Echenique, Maria Sol ULg; Belessi, X.; Butler, F. et al

in Journal of applied microbiology (2010), 109(5), 1790-9

AIM: To determine growth initiation differences of Listeria monocytogenes between a cheesemaking context, milk and tryptic soy broth (TSB). METHODS AND RESULTS: A laboratory-scale cheese was made with a ... [more ▼]

AIM: To determine growth initiation differences of Listeria monocytogenes between a cheesemaking context, milk and tryptic soy broth (TSB). METHODS AND RESULTS: A laboratory-scale cheese was made with a mix of two strains of L. monocytogenes at four initial pH values, five water activity (a(w)) values and two contamination levels at 30 degrees C. Counts of L. monocytogenes were determined at time 0 and after 8h of cheese manufacture. Milk and TSB at the same pH and a(w) conditions were inoculated with the L. monocytogenes mix in multi-well plates. Growth was determined by plating each well onto Agosti & Ottaviani Listeria Agar after 8h of incubation at 30 degrees C. Each condition was repeated six times, and growth initiation probability was modelled with logistic regression models. Growth initiation boundaries were obtained for each matrix type. The results showed that the growth limits were matrix dependent. In the three matrix types, a(w) was the most important factor affecting the probability of growth initiation. Contamination level affected growth TSB and cheesemaking conditions. CONCLUSIONS: The interface wideness and position in cheese, milk and TSB were dissimilar, indicating that the use of models evaluated in TSB or milk could not be used to predict the behaviour of L. monocytogenes under cheesemaking conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: Predictive models generated in liquid media are not necessarily adaptable to solid food, and the generation of real food models is necessary. [less ▲]

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See detailComparison of gut microbiota highfat induced modifications in young and old mice models
Taminiau, Bernard ULg; Neyrinck, A.; Delhalle, Laurent et al

Poster (2014, October 17)

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See detailComparison of Heterogeneous Transport Processes Observed with Electrical Resistivity Tomography in Two Soils
Garré, Sarah ULg; Koestel, Johannes; Günther, Thomas et al

in Vadose zone journal (2010), 9(2), 336-349

Preferential flow in soils can manifest itself in several ways. To illustrate this, we analyzed solute transport during a step tracer experiment in two soils expected to differ in their governing ... [more ▼]

Preferential flow in soils can manifest itself in several ways. To illustrate this, we analyzed solute transport during a step tracer experiment in two soils expected to differ in their governing transport processes: a loamy sand and a silty soil. By combining electrical resistivity tomography (ERT), time domain reflectometry, and effluent measurements, we observed different preferential flow phenomena. The transport process was characterized using voxel- and column-scale effective convective–dispersive equation (CDE) parameters, local velocities, and leaching surfaces. At the column scale, transport in the loamy sand was dominated by a homogenous convective–dispersive transport behavior, but at the scale of the voxel, preferential transport was observed. Transport in the silty soil was considerably more heterogeneous. Preferential flow was identified using ERT, voxel- and column-scale effective CDE parameters, local velocities, and leaching surfaces. In these soils, a clear influence of soil layering on solute transport was observed. [less ▲]

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See detailComparison of high spatial resolution trace metal distributions with model simulations for surface waters of the Gulf of Cadiz
Beckers, Jean-Marie ULg; Achterberg, Eric; Braungardt, Charlotte

in Estuarine Coastal & Shelf Science (2007), 74(4), 599-609

A multidisciplinary study in the Gulf of Cadiz is revisited, using additional diagnostic modelling tools. The dissolved trace metal (Cu, Ni, Zn, Cc) distributions in the Gulf of Cadiz are analysed using ... [more ▼]

A multidisciplinary study in the Gulf of Cadiz is revisited, using additional diagnostic modelling tools. The dissolved trace metal (Cu, Ni, Zn, Cc) distributions in the Gulf of Cadiz are analysed using modelled tracer evolutions, field observations and the concept of tracer ages. This Study shows that a significant part of the observed metal distributions can be explained by the metal inputs of three river systems (Guadiana, Rio Tinto and Odiel. Guadalquivir) discharging into the Gulf of Cadiz, while the remainder of the signal is most likely associated with the benthic metal remobilisation along the shelf of this coastal region. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailComparison of hindquarter metabolite uptakes in Belgian Blue double-muscled bulls at maintenance or during fattening.
Hornick, Jean-Luc ULg; Van Eenaeme, Christian ULg; Diez, Marianne ULg et al

in Journal of Animal Science (1997), 75(12), 3331-41

Metabolism of muscle growth in the hindquarter was investigated by the arterio-venous difference (AVD) technique in Belgian Blue double-muscled type bulls at maintenance or at fattening. The bulls were ... [more ▼]

Metabolism of muscle growth in the hindquarter was investigated by the arterio-venous difference (AVD) technique in Belgian Blue double-muscled type bulls at maintenance or at fattening. The bulls were fitted with an aortic ultrasonic blood flow probe and with catheters in the aorta and vena cava. They were offered a diet allowing for maintenance (MP) during a period of 15 d, at the end of which measurements were made over 3 d. Bulls were then given a fattening diet (FP) and the measurements were repeated. Arterial blood flow was approximately 1 L/min greater when the bulls were standing than when lying. Blood flow was 2 L/min higher during FP than during MP. The AVD and uptake of glucose were maximal at 1400 and 1600. Uptake of alpha-amino nitrogen decreased immediately after a meal. The increase in glucose from MP to FP fitted very well with the calculated energy needs for muscle growth. The AVD and uptake of alpha-amino nitrogen, total amino acids, and total nonessential amino acids were negative during MP and positive and significantly higher during FP. There was also a significant increase in AVD and uptake of essential and branched-chain amino acids when the bulls were changed from MP to FP. When changing from maintenance to fattening, the incremental glucose and amino acid hindquarter uptake provided energy and supply for muscle protein accretion, respectively. The level of alanine transamination was also sharply reduced. [less ▲]

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See detailComparison of horizontal and vertical advective CO2 fluxes at three forest sites
Feigenwinter, Christian; Bernhofer, Christian; Eichelmann, Uwe et al

in Agricultural and Forest Meteorology (2008), 148(1), 12-24

Extensive field measurements have been performed at three CarboEurope-Integrated Project forest sites with different topography (Renon/Ritten, Italian Alps, Italy; Wetzstein, Thuringia, Germany; Norunda ... [more ▼]

Extensive field measurements have been performed at three CarboEurope-Integrated Project forest sites with different topography (Renon/Ritten, Italian Alps, Italy; Wetzstein, Thuringia, Germany; Norunda, Uppland, Sweden) to evaluate the relevant terms of the carbon balance by measuring CO2 concentrations [CO2] and the wind field in a 3D multi-tower cube setup. The same experimental setup (geometry and instrumentation) and the same methodology were applied to all the three experiments. It is shown that all sites are affected by advection in different ways and strengths. Everywhere, vertical advection (F-VA) occurred only at night. During the day, F-VA disappeared because of turbulent mixing, leading to a uniform vertical profile of [CO2]. Mean F-VA was nearly zero at the hilly site (wetzstein) and at the flat site (Norunda). However, large, momentary positive or negative contributions occurred at the flat site, whereas vertical non-turbulent fluxes were generally very small at the hilly site. At the slope site (Renon), F-VA was always positive at night because of the permanently negative mean vertical wind component resulting from downslope winds. Horizontal advection also occurred mainly at night. It was positive at the slope site and negative at the flat site in the mean diurnal course. The size of the averaged non-turbulent advective fluxes was of the same order of magnitude as the turbulent flux measured by eddy-covariance technique, but the scatter was very high. This implies that it is not advisable to use directly measured quantities of the non-turbulent advective fluxes for the estimation of net ecosystem exchange (NEE) on e.g. an hourly basis. However, situations with and without advection were closely related to local or synoptic meteorological conditions. Thus, it is possible to separate advection affected NEE estimates from fluxes which are representative of the source term. However, the development of a robust correction scheme for advection requires a more detailed site-specific analysis of single events for the identification of the relevant processes. This paper presents mean characteristics of the advective CO2 fluxes in a first site-to-site comparison and evaluates the main problems for future research. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailComparison of HPV and cytology triage algorithms for women with borderline or mild dyskaryosis in population-based cervical screening (VUSA-screen study).
Rijkaart, Dorien C.; Berkhof, Johannes; van Kemenade, Folkert J. et al

in International journal of cancer. Journal international du cancer (2010), 126(9), 2175-81

We studied the effectiveness of high-risk human papillomavirus (hrHPV) triage for immediate colposcopy in women with borderline or mild dyskaryosis (BMD). In the Utrecht province of the Netherlands, women ... [more ▼]

We studied the effectiveness of high-risk human papillomavirus (hrHPV) triage for immediate colposcopy in women with borderline or mild dyskaryosis (BMD). In the Utrecht province of the Netherlands, women aged 30-60 years who participated in the regular cervical screening programme were offered hrHPV testing and cytology (intervention group) or cytology only (control group). In the intervention group (n = 337), women with BMD were immediately referred for colposcopy only if the sample was hrHPV positive. Women with a hrHPV negative test were advised to repeat cytology at 6 and 18 months and were referred for colposcopy if and when the repeat test result was positive (BMD or worse). In the control group (n = 329), referral of women with BMD was delayed until cytology was repeatedly positive at 6 or 18 months. The CIN3 detection rates were 10.7% (36/337) in the intervention group and 6.4% (21/329) in the control group (p = 0.047). Moreover, hrHPV triaging resulted in shorter time to diagnosis (154 vs. 381 days). Although the number of colposcopy referrals was 51.5% higher in the intervention group than in the control group, the medical costs per detected CIN3 were slightly lower ([euro] 4781 vs. [euro] 6235). If, in addition, hrHPV negative women had been referred back to routine screening at baseline, the CIN3 rate would have been 10.1% (34/337) and colposcopy rate would only have been 30.4% higher than in the control group. This study shows that hrHPV triaging of women with BMD is at least as effective for detecting CIN3 as repeat cytology, also when hrHPV negative women are referred back to routine screening. [less ▲]

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See detailComparison of HRGC-MS/MS and HRGC-HRMS results on environmental and food samples in some European laboraratories
Helen, Céline; Marchand, Philippe; Laplanche, Alain et al

in Organohalogen Compounds (2002)

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See detailComparison of Immune Reconstitution after Hematopoietic Stem Cell Transplantation with Flu-TBI versus TLI-ATG Conditioning
Hannon, Muriel ULg; Humblet-Baron, S.; Graux, C. et al

in Haematologica (2012), 97(Supplement 1), 180

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See detailComparison of Immune Reconstitution after Hematopoietic Stem Cell Transplantation with Flu-TBI versus TLI-ATG Conditioning
Hannon, Muriel ULg; Humblet-Baron, S.; Graux, C. et al

in Belgian Journal of Hematology (2013), Abstracts book(Supplement of 28th General Meeting of the Belgian Hematological Society), 38

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See detailComparison of Immune Reconstitution after Non-myeloablative Hematopoietic Cell Transplantation (HCT) with Flu-TBI versus TLI-ATG Conditioning
Hannon, Muriel ULg; Humblet-Baron, S.; Graux, C. et al

in Belgian Journal of Hematology (2011), Abstracts book(Supplement of 26th General Meeting of the Belgian Hematological Society), 8

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See detailComparison of impacts of dams on the annual maximum flow characteristics in three regulated hydrological regimes in Quebec (Canada).
Assani, A. A.; Stichelbout, E.; Roy, A. G. et al

in Hydrological Processes (2006)

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See detailComparison of impaired subcortico-frontal metabolic networks in normal aging, subcortico-frontal dementia, and cortical frontal demential
Garraux, Gaëtan ULg; Salmon, Eric ULg; Degueldre, Christian ULg et al

in Neuroimage (1999), 10(2), 149-162

Normal aging, progressive supranuclear palsy (PSP), and frontotemporal dementia (FTD) are characterized by different degrees of decline in frontal lobe functions. We used (18)FDG-PET and statistical ... [more ▼]

Normal aging, progressive supranuclear palsy (PSP), and frontotemporal dementia (FTD) are characterized by different degrees of decline in frontal lobe functions. We used (18)FDG-PET and statistical parametric mapping (SPM96) to compare relative subcorticofrontal metabolic impairment at rest in 21 healthy elderly subjects (HES), 20 PSP patients, and 6 FTD patients. When HES were compared to 22 healthy young subjects, widespread decrease in metabolism was observed in bilateral medial prefrontal areas including anterior cingulate cortices, in dorsolateral prefrontal areas, in left lateral premotor area, in Broca's area, and in left insula. In PSP compared to the 43 healthy subjects (HS), we observed subcorticofrontal metabolic impairment including both motor and cognitive neural networks. Impairment of functional connections between midbrain tegmentum and cerebellar, temporal and pallidal regions was demonstrated in PSP as compared to HS. When comparing FTD to HS, glucose uptake was primarily reduced in dorsolateral and ventrolateral prefrontal cortices and in frontopolar and anterior cingulate regions. There was also bilateral anterior temporal, right inferior parietal, and bilateral striatal hypometabolism. Finally, FTD showed more severe striatofrontal metabolic impairment than PSP, while mesencephalothalamic involvement was only observed in PSP. Our data suggest that subcorticofrontal metabolic impairment is distributed in distinct subcorticocortical networks in normal aging, PSP, and FTD. Subcorticofrontal dementia in PSP is related to hypometabolism in discrete frontal areas, which are probably disconnected from certain subcortical structures. The concept of subcortical dementia is reinforced by our data, which show disrupted functional connections between mesencephalon and cerebellar cortex, inferior and medial temporal regions, and pallidum. [less ▲]

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