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See detailDetermining fine population structure using iterative pruning
Chaichoompu, Kridsadakorn ULg; Yazew, Fentaw Abegaz; Tongsima, Sissades et al

Poster (2017, April 25)

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See detailDetermining fine population structure using iterative pruning
Chaichoompu, Kridsadakorn ULg; Yazew, Fentaw Abegaz; Tongsima, Sissades et al

Poster (2017, July 10)

SNP-based information is used in several existing clustering methods to detect shared genetic ancestry or to identify population substructure (Price et al. 2006, Raj et al. 2016). Here, we present an ... [more ▼]

SNP-based information is used in several existing clustering methods to detect shared genetic ancestry or to identify population substructure (Price et al. 2006, Raj et al. 2016). Here, we present an unsupervised clustering algorithm called the iterative pruning method to capture population structure (IPCAPS). Our method supports ordinal data which can be applied directly to SNP data to identify fine-level population structure and it is built on the iterative pruning Principal Component Analysis (ipPCA) algorithm (Intarapanich et al. 2009). The IPCAPS involves an iterative process using multiple splits based on multivariate Gaussian mixture modeling of principal components and Clustering EM estimation as in Lebret et al. (2015). In each iteration, rough clusters and outliers are also identified using our own method called RubikClust. The fixation index (FST) is known to measure a distance between populations and FST = 0.001 may be said to be genetically distinct among the European populations (Tian et al. 2008, Huckins et al. 2014). To observe fine-level population structure using FST, we examined simulated scenarios of one population, 500-8,000 individuals, 5,000-10,000 independent SNPs in HWE (Balding and Nichols 1995), with 100 replicates for each scenario. The simulated SNPs were encoded as additive coding and there was no missing genotype generated. We introduced negative control by subjecting individuals to be separated into two groups using kmeans. We observed that FST values of divided groups were lower than 0.0008, which can be defined as the minimum FST to detect fine-level population structure. To evaluate the performance of our method, we tested different simulated data sets of 2-3 populations, 250 individuals per population, 10,000 independent SNPs in HWE, and FST=[0.0008,0.005], with 100 replicates for each data set. For real-life data sets, we applied the IPCAPS to Thai (Wangkumhang et al. 2013) and HapMap populations. Our method showed that a population classification accuracy was superior to the ipPCA in simulated scenarios of extremely subtle structure (FST=[0.0009,0.005]). In case of the Thai population, results to detect fine-level structure were obtained as well as in case of the HapMap populations. We are convinced that the IPCAPS 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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See detailDetermining new threshold temperatures for cooling and heating degree day index of different climatic zones of Iran
Roshan, Gh.R.; Ghanghermeh, A.A.; Attia, Shady ULg

in Renewable Energy : An International Journal (2016), 101(2017), 156-167

Iran is a country with a variety of different climates. Determining the threshold temperatures suitable for providing thermal and climatic comfort is necessary and vital to its population well-being. This ... [more ▼]

Iran is a country with a variety of different climates. Determining the threshold temperatures suitable for providing thermal and climatic comfort is necessary and vital to its population well-being. This research presents new threshold temperatures in order to calculate the degree day index required for heating and cooling by taking advantage of the 12 stations that are representative of the diversity of Iran's climate. Using Olgyay diagram, different bioclimatic ranges of 12 weather stations and their frequencies were compiled, processes and analysed. Mean daily data of temperature and relative humidity were used for the period of 1950e2010. Based on the frequencies of temperature readings falling in Olgyay's diagram comfort zone, representive temperature thresholds were selected based on 40 to 60 percentiles or (P20), 25e75% percentile (P50) and the threshold of 10e90% percentile. The findings of this study shows that Mashhad with 29.6% and Anzali with 2.33% of frequencies, have experienced the maximum and minimum days of comfort. After analyzing various percentiles to determine the threshold temperatures, it was observed that there is a little difference among the stations for determining the minimum threshold for the comfort. Differences are more obvious in the maximum thresholds. In total, minimum base temperatures (HDD) belonged to Ardabil stations that were 20.50, 20.90 and 20 deg C for P20, P50 and P80 respectively. The maximum temperature for calculating CDD with values of (P20 ¼ 25 C; P50 ¼ 26.25 C; P80 ¼ 27.50 C) is dedicated to Zabol station. The findings present more reasonable thermal comfort thresholds that can be used by architects, engineers and policy makers to achieve, in turn, more energy efficient homes and high quality indoor and outdoor living environments. [less ▲]

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See detailDetermining prevalence of chronic kidney disease using estimated glomerular filtration rate.
Delanaye, Pierre ULg; Cavalier, Etienne ULg; Krzesinski, Jean-Marie ULg

in JAMA : Journal of the American Medical Association (2008), 299(6), 631

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See detailDetermining the characteristics of a free jet in 2-D by the SPH method
Lodomez, Maurine ULg

Master's dissertation (2014)

The Smoothed Particle Hydrodynamic method is a numerical method developed in 1977 to solve astrophysical problems. This numerical method is meshless, particle and Lagrangian and has been adapted to ... [more ▼]

The Smoothed Particle Hydrodynamic method is a numerical method developed in 1977 to solve astrophysical problems. This numerical method is meshless, particle and Lagrangian and has been adapted to hydraulic field. In this master’s thesis, the method is positioned relative to the classical numerical methods. The SPH formalism and its adaptation to hydraulic domain is exposed. The basics of SPH formalism are firstly the integral representation of a function and its derivative and secondly the particle approximation. The application of the SPH method to hydraulic domain is made by writting Navier Stokes equations in Lagrangian and SPH formalisms. Then, the specificities implemented in the code are tackled. These specificities are the state equation, the viscosity, the boundary conditions, the neighbors search and the problem initialization. Afterward, a modification of the initial didactic program, usable for constant domain in 3D, is performed. The changes are embodied to enable both 2D and 3D simulations with particle inflows and outflows. The validation of this modified code is performed thanks to four test cases. These test cases permit to validate the code and highlight the limitations of the method implemented such as kernel and the viscosity choices. Finally flows over sharped-crest weir have been simulated. These simulations were compared to results from the literature and experimental tests performed in the hydraulic laboratory. If some improvements are possible, such as injection and initialization of incoming particles, the results of these simulations show that the overall behavior of the free-jet is depicted. Indeed, the simulated jet admits a profile close to the experimental profiles. [less ▲]

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See detailDetermining the competence of mountainous Mediterranean streams using lichenometric techniques
Gob, F.; Jacob, N.; Bravard, J. P. et al

in International Association of Hydrological Sciences : “River Catchment Dynamics : Natural Processes and Human Impacts (2005)

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See detailDetermining the Geographical Origin of a Serial Offender Considering the Temporal Uncertainty of the Recorded Crime Data
Trotta, Marie ULg; Bidaine, Benoît ULg; Donnay, Jean-Paul ULg

in GEOProcessing 2011 : The Third International Conference on Advanced Geographic Information Systems, Applications, and Services (2011, February)

Since the days the investigating officers used ”pin maps” to locate and to think about crime events, crime mapping has become widespread thanks to spatial analysis mainly supplied by GIS-like software. In ... [more ▼]

Since the days the investigating officers used ”pin maps” to locate and to think about crime events, crime mapping has become widespread thanks to spatial analysis mainly supplied by GIS-like software. In particular these methods suit well to geographic profiling devoted to crime series characterised by a single offender and hence limited space and time variability. Although spatial techniques are now regularly performed to delineate an offender’s area of residence, the temporal dimension is underemployed due to the wider uncertainty of time records. This paper proposes a methodology based on a least-squares adjustment in order to cope with this temporal issue for determining the most probable offender’s residence. Moreover, a chi-square test is described to check the significance of the solutions suggested by the method. The process is carried out on the real road network which has been discretised (rasterised) for computing convenience. Three simulations show the validity of the reasoning. Finally the main time and speed assumptions introduced in the model are discussed paving the way for further research. [less ▲]

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See detailDetermining the reactivity of concrete aggregates for Nuclear Power Plant concrete structures
Jackiewicz-Rek, Wioletta; Piotrowski, Tomasz; Courard, Luc ULg et al

in Budowa Elektowni Jadrowych (2016), 529(9), 99-102

The authors describe the additional requirements to ensure durability of concrete related to probability of corrosion due to alkali-silica reactivity of aggregates based on French Rules for Design and ... [more ▼]

The authors describe the additional requirements to ensure durability of concrete related to probability of corrosion due to alkali-silica reactivity of aggregates based on French Rules for Design and Construction of PWR nuclear civil works RCC-CW. Since these requirements are based both on European standards and the French experience they are not fully compatible with the conditions and requirements in other countries, including Poland. In the paper the RILEM methodology and assessment according to American ASTM standards are presented as well. The article is an introduction to the discussion on adapting to Polish conditions the guidelines for the reactivity assessment of aggregate for concrete resulting from RCC-CW. [less ▲]

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See detailDetermining the Substorm Onset Instability Using Ground and Space-Based Measurements
Rae, Jonathan; Watt, Clare; Murphy, Kyle et al

Poster (2016, December 16)

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Peer Reviewed
See detailDeterminism in tropical forest biomass distribution due to forest spatial structure, highlighted by the study of the edge effect.
Bastin, Jean-François ULg; Bogaert, Jan; De Cannière, Charles

in Islands in land- and seascape: the challenges of fragmentation, Erlangen February 2012 (2012, February)

Detailed reference viewed: 35 (5 ULg)
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See detailDeterminisme de la derive lente de la frequence cardiaque pendant l'exercise musculaire.
Cornet, Françoise ULg; Scheen, André ULg; Juchmes, J. et al

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1978), 172(3), 569-74

The slow increase in heart rate which is observed in normal man submitted to heavy muscular exercise is due for a part to an activation of orthosympathetic cardiac activity which is blocked by beta ... [more ▼]

The slow increase in heart rate which is observed in normal man submitted to heavy muscular exercise is due for a part to an activation of orthosympathetic cardiac activity which is blocked by beta antagonists. It is also explained by direct action of hyperthermia on the heart. [less ▲]

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See detailLe determinisme genetique de la differenciation sexuelle humaine.
Ectors, Fabien ULg

in Revue Médicale de Bruxelles (1995), 16(6), 404-10

The genetic mechanism controlling sexual differentiation had remained unknown for a long time. Karyotype analysis of sex-inverted patients or individuals with ambiguous sexual differentiation has enabled ... [more ▼]

The genetic mechanism controlling sexual differentiation had remained unknown for a long time. Karyotype analysis of sex-inverted patients or individuals with ambiguous sexual differentiation has enabled the localization and identification of genes involved. It is currently known that the SRY gene is responsible for the initiation of a cascade reaction leading to male differentiation of the primitive gonad. SRY is a +/- 820 base pairs gene located on the small arm of the Y chromosome, more precisely within the 1A1 alpha sub-segment. Although a few other genes are known to be involved in the downstream regulation of SRY, their precise mode of action is yet unknown. [less ▲]

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See detailDéterminisme multifactoriel de l'héliodermie
QUATRESOOZ, Pascale ULg; uhoda, I.; PIERARD-FRANCHIMONT, Claudine ULg et al

in Actualités en Ingéniérie Cutanée (2006)

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See detailDeterministic and stochastic behaviour of L. monocytogenes suspended cells or detached from stainless steel surfaces during cheese manufacture
Belessi, C; Gounadaki, A; Schvartzman Echenique, Maria Sol ULg et al

Conference (2010, May)

Growth probability and kinetic models for Listeria monocytogenes in response to multiple hurdles occurring during cheese anufacturing are mainly focused on suspended L. monocytogenes cells. This study ... [more ▼]

Growth probability and kinetic models for Listeria monocytogenes in response to multiple hurdles occurring during cheese anufacturing are mainly focused on suspended L. monocytogenes cells. This study aimed to compared: (i) the growth/no growth interface of L. monocytogenes cells attached on stainless steel (SS) surfaces, or in suspension, within adjusted media and (ii) the behavior of planktonic and detached Listeria cells during manufacturing and ripening of two popular Greek cheeses: Feta and Graviera. A multi-strains composite of L. monocytogenes isolates from cheese, factory and farm in Greece and Ireland, were grown in TSBYE, MRD, Milk, Feta and Graviera cheese in the presence of SS coupons (2x5cm) for 3d at 20 °C, to obtain the following inocula: planktonic cells (P), and cells detached from the SS coupons (D). Detachment took place by the bead vortexing method. For growth/no growth evaluation P and D cells were inoculated in TSBYE, adjusted to 5 pH (6.8-4.8) by lactic acid and at 4 aw (0.945-0.995) by NaCl. For evaluation of L. monocytogenes kinetics in cheese, P and D cells were inoculated at three simulated stages of Feta and Graviera manufacture: in pasteurized milk, after cutting the curd and after the first ripening. The growth of D cells slightly delayed compared to P cells while it was more affected by aw than pH. On cheese, L. monocytogenes survived throughout the ripening at low levels. The differences in probability of growth of single cells for both inocula (P and D) were assessed by stochastic approaches. Furthermore, PFGE analysis resulted that 91 % of the cells of any tested condition belonged to the cheese factory isolate. The re- sults may address safety implications relevant to the potential of attached cells to proliferate, whereas data may contribute to filling data gaps on risk assessment of L. monocytogenes isolates from the dairy industry. [less ▲]

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See detailDeterministic and stochastic modelling for protection zone delineation
Rentier, Céline; Dassargues, Alain ULg

in Calibration and Reliability in Groundwater Modelling: A Few Steps Closer to Reality (2002)

Protection zones delimited by isochrones are often computed using calibrated groundwater flow and transport models. In heterogeneous formations, all direct (hard) and indirect (soft) data must be used ... [more ▼]

Protection zones delimited by isochrones are often computed using calibrated groundwater flow and transport models. In heterogeneous formations, all direct (hard) and indirect (soft) data must be used optimally. Approaches involving in situ pumping and tracer tests, combined with geophysical and/or other geological observations, should be developed. In a deterministic framework, the calibrated model is considered to be the best representation of reality at the current investigation stage, but uncertainty of the results is not quantified. Using stochastic methods, a range of equally likely isochrones can be produced, allowing us to quantify the influence of our knowledge on the aquifer parameters on protection-zone uncertainty. Furthermore, integration of soft data in a conditioned stochastic generation process, possibly associated with an inverse modelling procedure, can reduce the resulting uncertainty. Proposed is a stochastic methodology for protection-zone delineation, integrating hydraulic conductivity measurements (hard data), head observations and electrical resistivity data (soft data). [less ▲]

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See detailDeterministic generation of arbitrary symmetric states and entanglement classes
Lamata, Lucas; Lopez, C E; Lanyon, B P et al

in Physical Review. A (2013), 87

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See detailDeterministic Manufacturing constraints for Optimal Distribution in the Case of Additive Manufacturing
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg et al

Conference (2015, July 09)

An overview of the difficulties of coupling additive manufacturing to topology optimization with various solution founded and implemented.

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See detailA deterministic/stochastic model to predict the variation in bulk modulus of chalk
Collin, Frédéric ULg; Schroeder, Christian ULg; De Gennaro, Vincenzo et al

in Geotechnique (2005), 55(2), 135-141

Ekofisk, located 200 km west of the Norwegian coast, is one of the main oilfields in the North Sea. Since the early 1980s severe compaction of chalk reservoir layers has been observed as a consequence of ... [more ▼]

Ekofisk, located 200 km west of the Norwegian coast, is one of the main oilfields in the North Sea. Since the early 1980s severe compaction of chalk reservoir layers has been observed as a consequence of reservoir depletion during oil production. Subsequently, this compaction has been amplified by assisted oil recovery using seawater flooding. The development of our understanding of the inherent mechanisms of this phenomenon has been the objective of extensive experimental investigations in the last two decades. Owing to the very high cost of cored material from the reservoir, experiments are usually performed on chalk samples from an outcrop in Belgium lying at the same stratigraphic level as the Ekofisk reservoir chalks. However, even at the laboratory sample scale,. experimental variability of material response is observed. From a theoretical and numerical point of view, the determination of the mechanical properties of the material is of utmost importance for accurate modelling at both sample scale (laboratory tests) and reservoir scale. The aim of this paper is to introduce a stochastic approach within a deterministic constitutive model of chalk to enable the influence of material heterogeneity to be included in analyses for the range of observed mechanical responses. In modelling the random distribution of material parameters, the time-consuming Monte Carlo simulation method is replaced by a more efficient stochastic modelling technique. The results are given in the form of statistical parameters for the experimental laboratory test responses. The parameters of the distribution law (mean value, range of variation, spatial correlation structure) are fitted to reproduce the range of experimental responses observed at sample scale. Interest is focused on the variability of the chalk bulk modulus, as observed during isotropic compression tests. The proposed methodology provides a satisfactory explanation for the variability of response observed at the sample scale. The potential for extending the proposed approach to reservoir scale is briefly discussed. [less ▲]

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