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See detailComparison of isotopic turnover dynamics in two different muscles of a coral reef fish during the settlement phase
Gajdzik, Laura ULg; Lepoint, Gilles ULg; Lecchini, David et al

in Scientia Marina (2015), 79(3), 325-333

The temporal variation in carbon and nitrogen isotopic compositions (noted as δ13C and δ15N) was investigated in the convict surgeonfish (Acanthurus triostegus) at Moorea (French Polynesia). Over a period ... [more ▼]

The temporal variation in carbon and nitrogen isotopic compositions (noted as δ13C and δ15N) was investigated in the convict surgeonfish (Acanthurus triostegus) at Moorea (French Polynesia). Over a period of 24 days, juveniles were reared in aquaria and subjected to two different feeding treatments: granules or algae. The dynamics of δ13C and δ15N in two muscles (the adductor mandibulae complex and the epaxial musculature) having different functions were compared. At the end of experiments, a steady-state isotopic system in each muscle tissue was not reached. Especially for the algal treatment, we found different patterns of variation in isotopic compositions over time between the two muscles. The turnovers of δ13C showed opposite trends for each muscle but differences are mitigated by starvation and by the metamorphosis. Our study highlighted that the metabolism of coral reef fish may be subjected to catabolism or anabolism of non-protein precursors at settlement, inducing variation in isotopic compositions that are not linked to diet change. [less ▲]

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See detailComparison of IUE and HST diagnostic of the Jovian aurorae
Thomas, Alexandre ULg; Prangé; Ballester, G. E. et al

in Bulletin of the American Astronomical Society (1994, June 01)

Detailed reference viewed: 21 (1 ULg)
See detailComparison Of Jupiter's Infrared And Uv Aurorae With Simultaneous And Near-simultaneous HST And Ground-based Observations
Lystrup, Makenzie B; Radioti, Aikaterini ULg; Bonfond, Bertrand ULg et al

Conference (2010, October)

Jupiter's UV aurorae have been observed extensively for the last twenty years using the Hubble Space Telescope and the infrared aurorae have been investigated using ground-based telescope observations ... [more ▼]

Jupiter's UV aurorae have been observed extensively for the last twenty years using the Hubble Space Telescope and the infrared aurorae have been investigated using ground-based telescope observations. The two wavelength regimes complement each other; the UV is a tracer of inputs from the magnetosphere while the infrared emissions from the H3+ molecular ion show how the ionosphere responds to those inputs. Between 1995 and 2000 Spectroscopic, J.E.P Connerney & T. Satoh carried out observations with the NSFCAM imaging instrument at the NASA Infrared Telescope Facility. Results from this data set have been published, although the entire data set has not been examined and there has been only limited comparison with the UV. We reanalyze this data set in order to statistically characterize the infrared aurora and compare with the UV. Here we present a detailed study of simultaneous and near-simultaneous observations of the UV (STIS instrument on HST) and infrared northern aurorae made on July 26, 1998 and December 16, 2000. The comparative study addresses the main oval emissions, satellite footprints, and polar aurorae. M. Lystrup is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-0802021. [less ▲]

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See detailComparison of Kohonen's Self-Organizing Map algorithm and principal component analysis in the exploratory data analysis of a groundwater quality dataset
Peeters, Luk; Dassargues, Alain ULg

(2006)

Groundwater monitoring networks typically yield large, multivariate datasets. Analysis and interpretation of these datasets starts with an exploratory data analysis in order to summarize the available ... [more ▼]

Groundwater monitoring networks typically yield large, multivariate datasets. Analysis and interpretation of these datasets starts with an exploratory data analysis in order to summarize the available data, extract useful information and formulate hypotheses for further research. Exploratory data analysis is mostly focussed on finding related variables and groupings of similar observations. Traditionally multivariate statistical techniques like principal component analysis (PCA) are used for this purpose. In PCA a linear dimensionality reduction of the original, high dimensional dataset is carried out in order to identify orthogonal directions (principal components) of maximum variance in the dataset based on linear combinations of correlated variables. Projections of the original data in the subspace defined by the principal components can be used to identify groups in the data and to reveal relationships between variables (Davis, 1986). In this study, principal component analysis is compared to Kohonen's self-organizing map (SOM) algorithm. The SOM-algorithm is an artificial neural network technique designed to carry out a non-parametric regression process that is mainly used to represent high-dimensional, nonlinearly related data items in a topology-preserving, often two-dimensional display, and to perform unsupervised classification and clustering (Kohonen, 1995). Both PCA and SOM are applied to a hydrochemical dataset from a monitoring network in two sandy, phreatic aquifers in Central Belgium. The monitoring network consists of 47 monitoring wells each equipped with three filters at different depths, in which 14 variables are measured. The first aquifer, the Diest sands aquifer is of Late Miocene age and consists of coarse, glauconiferous sands and sandstones (Laga et al., 2001). The second aquifer, the Brussels sands aquifer, is of Middle Eocene age and is an heterogeneous formation consisting of an alteration of highly and poorly calcareous sands, locally silicified (Laga et al., 2001). Both techniques succeed in distinguishing between both aquifers and reveal the relationships between variables. The main advantage of PCA is the mathematical quantification of correlation between variables and the expression of the original data in the subspace defined by the principal components. The visualization of the SOM-analysis on the other hand allows a straightforward interpretation of the dataset structure in which even non-linear relationships between variables can be identified. Additionally, the SOM-algorithm can handle a limited amount of missing values in the dataset, contrary to PCA. [less ▲]

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See detailComparison of learning curves and skill transfer between classical and robotic laparoscopy according to the viewing conditions: implications for training
Blavier, Adelaïde ULg; Gaudissart, Quentin; Cadière, Guy-Bernard et al

in American Journal of Surgery (2007), 194(1), 115-121

BACKGROUND: The purpose of this study was to evaluate the perceptual (2-dimensional [2D] vs. 3-dimensional [3D] view) and instrumental (classical vs. robotic) impacts of new robotic system on learning ... [more ▼]

BACKGROUND: The purpose of this study was to evaluate the perceptual (2-dimensional [2D] vs. 3-dimensional [3D] view) and instrumental (classical vs. robotic) impacts of new robotic system on learning curves. METHODS: Forty medical students without any surgical experience were randomized into 4 groups (classical laparoscopy with 3D-direct view or with 2D-indirect view, robotic system in 3D or in 2D) and repeated a laparoscopic task 6 times. After these 6 repetitions, they performed 2 trials with the same technique but in the other viewing condition (perceptive switch). Finally, subjects performed the last 3 trials with the technique they never used (technical switch). Subjects evaluated their performance answering a questionnaire (impressions of mastery, familiarity, satisfaction, self-confidence, and difficulty). RESULTS: Our study showed better performance and improvement in 3D view than in 2D view whatever the instrumental aspect. Participants reported less mastery, familiarity, and self-confidence and more difficulty in classical laparoscopy with 2D-indirect view than in the other conditions. CONCLUSIONS: Robotic surgery improves surgical performance and learning, particularly by 3D view advantage. However, perceptive and technical switches emphasize the need to adapt and pursue training also with traditional technology to prevent risks in conversion procedure. [less ▲]

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See detailComparison of less lethal 40 mm sponge projectile and the 37 mm projectile for injury assessment on human thorax
Nsiampa Ndompetelo, ULg; Robbe, Cyril ULg

in 10th International Conference on the mechanical and physical behaviour of materials under dynamic loading, Freiburg 2-7 September 2012 (2012)

Detailed reference viewed: 31 (0 ULg)
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See detailComparison of levels of cytosol estrogen receptors with "arterial" and "venous" concentrations of gonadic steroids in mammary tumors.
Duvivier, Joseph; Colin, Claude; Hustin, Jean et al

in Clinica Chimica Acta (1981), 112(1), 21-32

Plasma steroid concentrations measured in the post-menopausal women with breast cancer showed a close correlation between the various androgens. The post-menopausal women exhibited a correlation between ... [more ▼]

Plasma steroid concentrations measured in the post-menopausal women with breast cancer showed a close correlation between the various androgens. The post-menopausal women exhibited a correlation between estrogen receptors (ER) and "arterial" 17 alpha-hydroxyprogesterone levels in the breast. ER levels expressed as a function of plasma (arterial) steroid (P/17 P) molar concentration ratio were distributed within a hyperbola, suggesting the existence of a control mechanism for breast cell ER levels. [less ▲]

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See detailComparison of liaison N-tact PTH (diasorin) and N-tact PTH SPIRMA (diasorin) in hemodialyzed patients
Cavalier, Etienne ULg; Delanaye, Pierre ULg; Krzesinski, Jean-Marie ULg et al

in Clinical Chemistry & Laboratory Medicine (2005), 43(8), 890-891

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See detailComparison of Life cycle Impact Assessment methods in a case of crop in Northern France
Merchan, Angel ULg; Combelles, Agathe

Poster (2014, November 05)

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See detailComparison of Life cycle Impact Assessment methods in a case of crop in Northern France
Merchan, Angel ULg; Combelles, Agathe

in Proceeding of the 4th international conference on Life Cycle approaches (2014, November 05)

Life Cycle Assessment (LCA) applied to the agri-food sector has been rapidly developing in the last years, however initiatives like Agribalyse® have shown the lack of consensus making on the impact ... [more ▼]

Life Cycle Assessment (LCA) applied to the agri-food sector has been rapidly developing in the last years, however initiatives like Agribalyse® have shown the lack of consensus making on the impact assessment phase (choice of characterization methods). A review of the proceedings of the 8th International Conference on Life Cycle Assessment in the Agri-Food Sector (LCAFood 2012) revealed the absence of prevalence of a life cycle impact assessment (LCIA) method, where several calculation methods and variations of them are used. [less ▲]

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See detailComparison of linkage and association strategies for quantitative traits using the COGA dataset
McQueen, M. B.; Murphy, A.; Kraft, P. et al

in Genetic Epidemiology. Supplement (2005), 29(Suppl I), 1-9

Genome scans using dense single-nucleotide polymorphism ( SNP) data have recently become a reality. It is thought that the increase in information content for linkage analysis as a result of the denser ... [more ▼]

Genome scans using dense single-nucleotide polymorphism ( SNP) data have recently become a reality. It is thought that the increase in information content for linkage analysis as a result of the denser scans will help refine previously identified linkage regions and possibly identify new regions not identifiable using the sparser, microsatellite scans. In the context of the dense SNP scans, it is also possible to consider association strategies to provide even more information about potential regions of interest. To circumvent the multiple-testing issues inherent in association analysis, we use a recently developed strategy, implemented in PBAT, which screens the data to identify the optimal SNPs for testing, without biasing the nominal significance level. We compare the results from the PBAT analysis to that of quantitative linkage analysis on chromosome 4 using the Collaborative Study on the Genetics of Alcoholism data, as released through Genetic Analysis Workshop 14. [less ▲]

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See detailComparison of linkage and association strategies for quantitative traits using the COGA dataset.
McQueen, M. B.; Murphy, A.; Kraft, P. et al

in BMC Genetics (2005), 6 Suppl 1

ABSTRACT : Genome scans using dense single-nucleotide polymorphism (SNP) data have recently become a reality. It is thought that the increase in information content for linkage analysis as a result of the ... [more ▼]

ABSTRACT : Genome scans using dense single-nucleotide polymorphism (SNP) data have recently become a reality. It is thought that the increase in information content for linkage analysis as a result of the denser scans will help refine previously identified linkage regions and possibly identify new regions not identifiable using the sparser, microsatellite scans. In the context of the dense SNP scans, it is also possible to consider association strategies to provide even more information about potential regions of interest. To circumvent the multiple-testing issues inherent in association analysis, we use a recently developed strategy, implemented in PBAT, which screens the data to identify the optimal SNPs for testing, without biasing the nominal significance level. We compare the results from the PBAT analysis to that of quantitative linkage analysis on chromosome 4 using the Collaborative Study on the Genetics of Alcoholism data, as released through Genetic Analysis Workshop 14. [less ▲]

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See detailComparison of local outliers detection techniques in spatial multivariate data
Ernst, Marie ULg; Haesbroeck, Gentiane ULg

in Data Mining & Knowledge Discovery (2017), 31(2), 371399

Outlier detection techniques in spatial data should allow to identify two types of outliers: global and local ones. Local outliers typically have non-spatial attributes that strongly differ from those ... [more ▼]

Outlier detection techniques in spatial data should allow to identify two types of outliers: global and local ones. Local outliers typically have non-spatial attributes that strongly differ from those observed on their neighbors. Detecting local outliers requires to be able to work locally, on neighborhoods, in order to take into account the spatial dependence between the statistical units under consideration, even though the outlyingness is usually measured on the non-spatial variables. Many procedures have been outlined in the literature, but their number reduces when one wants to deal with multivariate non-spatial attributes. In this paper, focus is on the multivariate context. A review of existing procedures is done. A new approach, based on a two-step improvement of an existing one, is also designed and compared with the benchmarked methods by means of examples and simulations. [less ▲]

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See detailComparison of Lohmann white and Lohmann brown strains in embryo physiology
Tona, K.; Agbo, K.; Kamers, B. et al

in International Journal of Poultry Science (2010), 9(9), 907-910

Chicken post-hatch performance is known to be related to embryonic developmental parameters. However, strain or genotype differences with regard to embryo physiological parameters have received little ... [more ▼]

Chicken post-hatch performance is known to be related to embryonic developmental parameters. However, strain or genotype differences with regard to embryo physiological parameters have received little attention. A total of 1,200 hatching eggs produced by Lohmann Brown (LB) and Lohman White (LW) breeders of the same age were studied. Between 62 and 150 h of incubation, eggs Resonance Frequency (RF) was measured as indicator of early embryonic development. Also, albumen pH was measured between setting and d 8 of incubation. From d 10 to 18 of incubation, remaining albumen and embryos were weighed. During the last days of incubation, hatching occurrences were monitored after every four hours and hatched chicks were recorded. Results indicate that RF of LWeggs were lower than that of LB eggs (p<0.01) and starting time point of RF decrease occurred earlier in LB eggs than in LW eggs. Albumen pH of LB eggs was lower than that of LW eggs at day 8 of incubation. Remaining albumen weight at 14 and 16 d of incubation was lower in LB than in LW (p<0.05) while embryo weights increased more rapidly in LB strain than in LW strain. It is concluded that LB and LW embryos have different growth trajectories and should be incubated at different conditions. © Asian Network for Scientific Information, 2010. [less ▲]

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See detailComparison of Machine Learning techniques for atmospheric pollutant monitoring in a Kraft pulp mill
Sainlez, Matthieu ULg; Heyen, Georges ULg

Conference (2011, November)

In this paper, machine learning techniques are compared to predict nitrogen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data ... [more ▼]

In this paper, machine learning techniques are compared to predict nitrogen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data related to a Kraft recovery boiler, we consider a regression problem in which we are trying to predict the value of a continuous variable. Generalization is done on the worst case configuration possible to make sure the model is adequate: the training period concerns stationary operations while test periods mainly focus on NOx emissions during transient operations. This comparison involves neural network techniques (i.e., static multilayer perceptron and dynamic NARX network), tree-based methods and multiple linear regression. We illustrate the potential of a dynamic neural approach compared to the others in this prediction task. [less ▲]

Detailed reference viewed: 31 (9 ULg)