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See detailComparison of magnetotail magnetic flux estimates based on global auroral images and simultaneous solar wind—magnetotail measurements
Shukhtina, M. A.; Sergeev, V. A.; Dejong, A. D. et al

in Journal of Atmospheric & Solar-Terrestrial Physics (2010), 72

We compared simultaneous magnetotail magnetic flux F estimates, (1) based on in situ spacecraft measurements in the tail and solar wind (F[SUB]T[/SUB]) with (2) the polar cap magnetic flux, estimated from ... [more ▼]

We compared simultaneous magnetotail magnetic flux F estimates, (1) based on in situ spacecraft measurements in the tail and solar wind (F[SUB]T[/SUB]) with (2) the polar cap magnetic flux, estimated from global auroral images (using proton-induced or electron-induced emissions, F[SUB]p[/SUB] or F[SUB]e[/SUB], respectively). Simultaneous F[SUB]p[/SUB] and F[SUB]e[/SUB] estimates gave the correlation coefficient CC=0.74, indicating that these measures are not absolutely precise. Regression analysis of F[SUB]T[/SUB] versus F[SUB]e[/SUB] and F[SUB]p[/SUB] gave CC values 0.73 and 0.50, correspondingly. F[SUB]T[/SUB] values, containing closed magnetic flux, are systematically higher than F[SUB]p[/SUB] and F[SUB]e[/SUB] by 20-30%. Motivated by diverse results, published by different groups, we reanalyzed the F dependence on the dayside merging electric field E[SUB]m[/SUB] for different dynamical states. The linear regression F(E[SUB]m[/SUB]) for substorm onsets shows a large slope ˜0.07-0.12GWb/(mV/m) for all F[SUB]p[/SUB], F[SUB]e[/SUB] and F[SUB]T[/SUB], confirming the loading-unloading substorm scheme. For SMC intervals this slope is only 0.03 GWb/(mV/m). [less ▲]

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See detailComparison of marketing strategies of retailers of organic beef
Aertsens, Joris; Stassart, Pierre M ULg; Jamar, D. et al

in Quality Management and Quality Assurance in Food Chains (2005)

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See detailComparison of mechanical efficiency of two microstructures of Ti5553 alloy in the case of bolted flanges submitted to tensile loading
Van Hoof, T.; Ben Bettaieb, Mohamed ULg; Lani, F. et al

in Steel Research International (2010), 81(9), 1148-1152

A combination of numerical and experimental methods is used to compare the efficiency of two microstructures of Ti5553 titanium alloy in an industrial test case. The test case consists in two parts of ... [more ▼]

A combination of numerical and experimental methods is used to compare the efficiency of two microstructures of Ti5553 titanium alloy in an industrial test case. The test case consists in two parts of sectors of aircraft engine stators linked together by an Inconel bolt and submitted to tensile loading. The efficiency of these microstructures is evaluated by using finite element (FE) models. The chosen FE models take into account elasto-visco-plastic material behaviors, contact with friction (bolt heads/flanges and flange/flange), and the initial bolt tightening. The parameters of the elasto-visco-plastic (EVP) material law are adjusted from experimental results extracted from tensile tests performed on Inconel, and Ti5553 alloys. Viscous properties are observed at different strain rates. The studied alloy is assumed to be plastically isotropic. In order to compare the fracture resistance of both microstructures, a micro-mechanical (damage based) rupture model ([4]) is used as a FE post-processing step. [less ▲]

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See detailComparison of mesozooplankton faecal pellet characteristics from the Southern North Sea and the Mediterranean Sea during spring bloom conditions
Frangoulis, Constantin; Hecq, Jean-Henri ULg

in Gislason, Astthor; Gorsky, Gabriel (Eds.) Proceedings of the « Joint ICES / CIESM Workshop to Compare Zooplankton Ecology and Methodologies between the Mediterranean and the North Atlantic (WKZEM) » (2010, February)

Mesozooplankton faecal pellets participate in the carbon and nutrient cycles, in the nutrition of marine organisms, and in the transport of toxins, pollutants, and sediments. The importance of this role ... [more ▼]

Mesozooplankton faecal pellets participate in the carbon and nutrient cycles, in the nutrition of marine organisms, and in the transport of toxins, pollutants, and sediments. The importance of this role depends on their nature and production, which are highly variable parameters that, in turn, depend on many factors. For example, a phytoplankton bloom may significantly change the nature of mesozooplankton faecal pellets because it affects their shape, content, density, and volume. The aim of the present study is to compare the eutrophic Southern North Sea and the oligotrophic Bay of Calvi in the Meditenanean Sea with respect to the seasonal variability of faecal pellet characteristics (shape, size, sinking speed, density) during bloom conditions. [less ▲]

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See detailA Comparison of Methods for Photospheric Abundance Determinations in K-Type Stars
Affer, L.; Micela, G.; Morel, Thierry ULg et al

in Chemical Abundances and Mixing in Stars in the Milky Way and its Satellites, ESO ASTROPHYSICS SYMPOSIA. ISBN 978-3-540-34135-2. Springer-Verlag, 2006, p. 31 (2006)

We have performed a detailed abundance analysis of six inactive K-type stars using high-resolution optical spectra. We have used three different techniques and compared the results obtained in order to ... [more ▼]

We have performed a detailed abundance analysis of six inactive K-type stars using high-resolution optical spectra. We have used three different techniques and compared the results obtained in order to establish their respective merits and faults. The two spectroscopic methods give consistent results suggesting that non- LTE effects are small, whereas the â mixedâ spectroscopic-photometric method leads to photospheric parameters and abundances systematically lower than those obtained with the other two. We have also determined the starsâ positions in H-R diagrams and made a comparison between the gravities derived from the ionization equilibrium of the iron lines and from the evolutionary tracks: the agreement is reasonably good. [less ▲]

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See detailComparison of methods for quantifying active layer dynamics and bedload discharge in armoured gravel-bed rivers
Houbrechts, Geoffrey ULg; Van Campenhout, Jean ULg; Levecq, Yannick ULg et al

in Earth Surface Processes & Landforms (2012), 37

Several methods were employed in the Ardennian rivers (Belgium) to determine the depth of the active layer mobilized during floods and to evaluate the bedload discharge associated with these events. The ... [more ▼]

Several methods were employed in the Ardennian rivers (Belgium) to determine the depth of the active layer mobilized during floods and to evaluate the bedload discharge associated with these events. The use of scour chains has shown that the depth of the active layer is systematically less than the b-axis of the average particle size (D50) of the elements which compose the surface layer of the riffles. This indicates that only a partial transport exists during low magnitude floods. The bedload discharge has been evaluated by combining data obtained using the scour chains technique and the distance covered by tracers. Quantities of sediment transported during frequent floods are relatively low (0 02 t km–2) due to the armour layer which protects the subsurface material. These low values are also related to the fact that the distance calculated for mobilized bedload only applies to tracers fitted with PIT (passive integrated transponder)-tags (diameter>20 mm), whereas part of the bedload discharge is composed of sand and fine gravel transported over greater distances than the pebbles. The break-up of the armour layer was observed only once, for a decennial discharge. During this event, the bedload discharge increased considerably (2 t km–2). The use of sediment traps, data from dredging and a Helley–Smith sampler confirm the low bedload transport in Ardennian rivers in comparison to the bedload transport in other geomorphological contexts. This difference is explained by the presence of an armoured layer but also by the imbricated structures of flat bed elements which increase the resistance to the flow. Finally, the use of the old iron industry wastes allowed to quantify the thickness of the bed reworked over the past centuries. In the Lembrée River, the river-bed contains slag elements up to a depth of about 50 cm, indicating that exceptional floods may rework the bed to a considerable depth. [less ▲]

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See detailComparison of methods for the detection and extrapolation of trends in groundwater quality
Visser, Ate; Dubus, Igor; Broers, Hans Peter et al

in Journal of Environmental Monitoring (2009)

Land use changes and the intensification of agriculture since the 1950s have resulted in a deterioration of groundwater quality in many European countries. For the protection of groundwater quality, it is ... [more ▼]

Land use changes and the intensification of agriculture since the 1950s have resulted in a deterioration of groundwater quality in many European countries. For the protection of groundwater quality, it is necessary to (1) assess the current groundwater quality status, (2) detect changes or trends in groundwater quality, (3) assess the threat of deterioration and (4) predict future changes in groundwater quality. A variety of approaches and tools can be used to detect and extrapolate trends in groundwater quality, ranging from simple linear statistics to distributed 3D groundwater contaminant transport models. In this paper we report on a comparison of four methods for the detection and extrapolation of trends in groundwater quality: (1) statistical methods, (2) groundwater dating, (3) transfer functions, and (4) deterministic modeling. Our work shows that the selection of the method should firstly be made on the basis of the specific goals of the study (only trend detection or also extrapolation), the system under study, and the available resources. For trend detection in groundwater quality in relation to diffuse agricultural contamination, a very important aspect is whether the nature of the monitoring network and groundwater body allows the collection of samples with a distinct age or produces samples with a mixture of young and old groundwater. We conclude that there is no single optimal method to detect trends in groundwater quality across widely differing catchments. [less ▲]

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See detailComparison of microleakage of photo-cured composites using three different light sources: halogen lamp, LED and argon laser: an in vitro study
Tielemans, M.; Compère, Philippe ULg; Geerts, Sabine ULg et al

in Lasers in Medical Science (2009), 24(1), 1-5

In this study, we compared the microleakage of composite fillings cured with halogen bulb, LED and argon ion laser (488 nm). Twenty-four extracted human molars were divided randomly in three groups. Six ... [more ▼]

In this study, we compared the microleakage of composite fillings cured with halogen bulb, LED and argon ion laser (488 nm). Twenty-four extracted human molars were divided randomly in three groups. Six cavities were prepared on the coronal part of each tooth. Standard cavities (1.7 x 2 mm) were prepared. Cavities were acid etched, sealed with Scotch Bond 1 and filled by a hybrid composite. Cavities were exposed to one light source, thermocycled and immersed in a 2% methylene blue dye solution. Dye penetration in the leakage of cavities was recorded using a digital optical microscope. Mean values of percentage of dye penetrations in microleakages of cavities were 49.303 +/- 5.178% for cavities cured with LED, 44.486 +/- 6.075% with halogen bulb and 36.647 +/- 5.936% for those cured by argon laser. Statistically significant difference exists between cavities cured by halogen vs LED (P < 0.01), halogen vs laser (P < 0.001) and LED vs laser (P < 0.001). The lowest microleakage was observed in the cavities and composites cured with argon ion laser. [less ▲]

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See detailComparison of Microwave-Assisted Hydrodistillation and and Traditional Hydrodistillation Methods for the Rosmarinus eriocalyx essential oils from Eastern Morocco
Fadel, O.; Ghazi, K.; Mouni, L. et al

in Journal of materials and environmental science (2011), 2(2),

Volatile compounds of Rosmarinus eriocalyx samples were extracted by steam-hydrodistillation (HD) and microwave-assisted hydrodistillation (MAH). GC-MS and GC-FID analysis of the oils revealed the ... [more ▼]

Volatile compounds of Rosmarinus eriocalyx samples were extracted by steam-hydrodistillation (HD) and microwave-assisted hydrodistillation (MAH). GC-MS and GC-FID analysis of the oils revealed the presence of 22 and 26 compounds in the essential oils obtained through HD and MAH, respectively. The total yield of the volatile fractions obtained through HD and MAH was 1.21% and 1.47%, respectively. The two oils contained the same dominant components: camphor (35.92% HD; 35.33% MAH), camphene (19.74%; 17.07%), a-pinene (14.53%; 12.87%), and 1,8-cineol (6.52%; 6.73%). Higher amounts of oxygenated monoterpenes such as borneol, 1,8-cineol, isobornyl acetate, a-terpeneol, caryophyllene oxide (13.59%) were present in the oil of MAH in comparison with HD (12.36%). However, HD oil contained more monoterpene hydrocarbons such as tricyclene, a-pinene, camphene, o-cymene and limonene (39.04%) than MAH extracted oil (34.45%). [less ▲]

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See detailComparison of mineral intake between children from endemic and non-endemic areas for Kashin-Beck disease in Tibet Autonomous Region: Pilote study
DERMIENCE, Michael ULg; Maesen, Philippe ULg; Mathieu, Françoise et al

Poster (2012, June 01)

Background The Kashin-Beck disease (KBD) is an endemic and chronic osteochondropathy affecting between 0.74 million and 2.5 million people in the Tibet Autonomous Region and in several provinces of the ... [more ▼]

Background The Kashin-Beck disease (KBD) is an endemic and chronic osteochondropathy affecting between 0.74 million and 2.5 million people in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. The etiology remains unclear, although a multifactorial hypothesis has been proposed (selenium/iodine deficiency; high concentration of organic matters in drinking water; and mycotoxin poisoning by fungi infecting cereals). The rural population is almost exclusively affected. Objectives The first objective of this study was to assess and to compare the mineral daily intake between Tibetan preschool children living in endemic areas for the Kashin-Beck disease and those living in non-endemic areas. A second objective was the comparison of children daily intakes with Chinese Dietary Reference Intakes (DRIs). The third objective was to estimate a sample size for a cross-sectional survey aiming to highlight significant differences in mineral intakes between the two groups of preschool children. Materials and Methods Ten Tibetan preschool children were enrolled per group (endemic/non-endemic) for this pilot study. Children had to be weaned and those living in endemic area must have a KBD sibling. The nutrition survey consisted in an interactive simplified 24-hour recall questionnaire. Two 24-hour recalls were recorded for the endemic group, in February 2010 (EAw) and in May 2010 (EAs), while one day has been recorded for the non-endemic group in July 2011 (NEA). At the same time, samples of the main staple foods were collected for chemical analysis. The daily intakes of Ca, P, Mg, Fe, Zn, Cu, and Mn were calculated based on the 24-hour recall records, the chemical analyses, and data from food composition tables (FCTs). Results and discussion We are aware of limitations in the methodological approach of this pilot-study. The number of children, although weak, was empirically decided for the sake of feasibility and because no prior information was available. The interactive 24-hour recalls between the two groups are spaced in time. Nevertheless, the diet of rural Tibetans is far from diversified, and the variability among seasons and years is probably low. Daily intakes in Ca, P, Mg, Fe, Zn, Cu and Mn were calculated for children of each group. Parametric test were applied for comparison of mean daily intakes between groups. A significant difference was highlighted for Cu (p-value<0.01) and Fe (p-value<0.05), no other significant difference was detected. When comparing individual daily intakes and Chinese DRIs, the most striking results concern Ca and Mn. The great majority of children showed severe deficiency in calcium and enormous excess in manganese. A power (1-β) of 80% is commonly accepted when estimating a sample size for a cross-sectional survey. In this case, the maximum sample size is too high and not feasible in practice (several hundred children per group). Oppositely, the power was calculated per mineral, based on 100 children per group. The power is higher than 90% for Mg, Fe, and Cu. For the others minerals, the power is well below 80%. Nevertheless, general deficiencies and excesses have been observed in the two groups for part of these minerals. We believe that it is a statement in itself and trying to highlight small differences between groups in such extremes is not relevant. [less ▲]

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See detailThe comparison of mode choice sensitivity to the reduction of travel time and cost in multimodal trip
Ganji, Mohammad; Eftekhar, Hamed ULg; Foad, Shokri et al

in Research Journal of Applied Sciences, Engineering and Technolog (2013), 6(9), 1680-1684

Nowadays, with the extension of travel distances and accessibility to the various commuting options, multimodal trip proposes as the most competent travelling strategy. However, with increasing in demand ... [more ▼]

Nowadays, with the extension of travel distances and accessibility to the various commuting options, multimodal trip proposes as the most competent travelling strategy. However, with increasing in demand by using these options as well as metro, subway, buses, cycles and sidewalk, some problems arose. The import of this quantitative study is to sympathize with the significance of the multimodal as a novel factor in the transportation. In this study, we discussed about cost and time as two significant factors, which affect everybody's life. While improving these two factors have a meaningful effect on encouraging/discouraging private vehicle commuters to switch to public transport. The methodology of this study is an empirical research in which a survey was conducted among the students at The National University of Malaysia with a numeric sample. Hence, a case study based on areas around UKM campus is used to emonstrate the results. What were investigated in this study were the attributes of a reduction in either travel cost or time to promote people who use their own vehicles to shift toward public transportation. The results show that the two factors: time and cost made a significant contribution in motivating private vehicle users to switch public transport. However, the most important purpose of this study was determining the most effective factor (at least based on our condition) since it's not practically possible to have the travel time and cost reduction together [less ▲]

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See detailThe comparison of mode choice sensitivity to the reduction of travel time and cost in multimodal trip
Ganji, Mohammad; Eftekhar, Hamed ULg; Ismail, Amiruddin et al

Scientific conference (2012)

Nowadays, with the extension of travel distances and accessibility to the various commuting options, multimodal trip proposes as the most competent travelling strategy. However, with increasing in demand ... [more ▼]

Nowadays, with the extension of travel distances and accessibility to the various commuting options, multimodal trip proposes as the most competent travelling strategy. However, with increasing in demand by using these options as well as metro, subway, buses, cycles and sidewalk, some problems arose. The import of this quantitative study is to sympathize with the significance of the multimodal as a novel factor in the transportation. In this study, we discussed about cost and time as two significant factors, which affect everybody's life. While improving these two factors have a meaningful effect on encouraging/discouraging private vehicle commuters to switch to public transport. The methodology of this study is an empirical research in which a survey was conducted among the students at The National University of Malaysia with a numeric sample. Hence, a case study based on areas around UKM campus is used to demonstrate the results. What were investigated in this study were the attributes of a reduction in either travel cost or time to promote people who use their own vehicles to shift toward public transportation. The results show that the two factors: time and cost made a significant contribution in motivating private vehicle users to switch public transport. However, the most important purpose of this study was determining the most effective factor (at least based on our condition) since it's not practically possible to have the travel time and cost reduction together [less ▲]

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See detailComparison of modeled and empirical approaches for retrieving columnar water vapor from solar transmittance measurements in the 0.94 micrometer region
Schmid, B; Thome, K.J.; Demoulin, Philippe ULg et al

in Journal of Geophysical Research (1996), 101

Four atmospheric transmittance models, LOWTRAN 7, MODTRAN 3, FASCOD3P, and the Thomason model, are investigated to quantify the relationship between water vapor transmittance as function of water vapor ... [more ▼]

Four atmospheric transmittance models, LOWTRAN 7, MODTRAN 3, FASCOD3P, and the Thomason model, are investigated to quantify the relationship between water vapor transmittance as function of water vapor amount, Tw (U), for an instrument specific band pass in the 0.94-um region. In a second step an empirical Tw (U) function is established using long term measurements with our high-precision Sun photometer (SPM) in Bern, Switzerland along with 1300 simultaneous and collocated water vapor retrievals performed with a dual-channel microwave radiometer (MWR). In order to avoid a possible bias in the empirical Tw(U) function, the MWR data set is prescreened by comparing retrievals coincident with radiosonde ascents. Over a 2 1/2-year period of common observations, radiosondes and PM agreed to within 0.19 cm (13%) of columnar water vapor (CWV) using the empirical Tw (U) relationship. Completely independent comparisons with an additional MWR and two Fourier transform spectrometers yielded agreement within 13% and 9%, respectively. Comparing empirical and modeled results, we found that with respect to the experimental data, LOWTRAN 7, MODTRAN 3, and FASCOD3P reported higher water vapor transmittances over almost the entire range of realistic absorber amounts. By relating these differences to differences in retrieved CWV for the case of two standard atmospheres, we found that using Tw (U) predicted by LOWTRAN 7, MODTRAN 3, and FASCOD3P leads to an overestimate of CWV by about 18-30%, 7-20%, and 2-18%, respectively. The Thomason model yields good agreement with respect to the experimental data up to medium absorber amounts, whereas at slant path amounts larger than 10 cm, errors up to 60% in retrieved CWV occurred. We also show in this work that a misinterpretation of the LOWTRAN 7 water vapor output counterbalances incorrectly predicted Tw, leading to results that agree well with experimental ones [less ▲]

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See detailComparison of monoamine concentrations in the brains of adult male and female Japanese quail.
Ottinger, M. A.; Schumacher, M.; Clarke, R. N. et al

in Poultry Science (1986), 65(7), 1413-20

A fluorometric assay measuring brain tissue concentrations of norepinephrine, dopamine, and serotonin has been validated for Japanese quail. Accuracy, precision, specificity, and parallelism were ... [more ▼]

A fluorometric assay measuring brain tissue concentrations of norepinephrine, dopamine, and serotonin has been validated for Japanese quail. Accuracy, precision, specificity, and parallelism were determined. The sensitivity of the assays was 6 ng/tube, which allowed individual assay of 1 to 2 mg hypothalamic tissue. In Experiment 1, relatively large areas of brain from adult, reproductively active males and females were found to differ significantly in norepinephrine content in optic lobes and for dopamine in right telencephalon. A microdissection technique was used in Experiment 2 to sample small portions of hypothalamic tissue. Sex differences were observed for norepinephrine in the sections containing the lobus paraolfactorius and the preoptic, anterior, and medial hypothalamus. Differences in monoamine content were most apparent when smaller areas dissected by microdissection were analyzed. These results give evidence for sex differences in the monoamine content in specific areas of the brain. [less ▲]

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See detailComparison of monooxygenase activities and cytochrome P-450 isozyme concentrations in human liver microsomes.
Beaune, P H; Kremers, P G; Kaminsky, L S et al

in Drug Metabolism and Disposition : The Biological Fate of Chemicals (1986), 14(4), 437-42

Concentrations of three human liver microsomal cytochrome P-450 isozymes and 20 different monooxygenase activities were determined in human liver microsomal preparations. The results of correlation ... [more ▼]

Concentrations of three human liver microsomal cytochrome P-450 isozymes and 20 different monooxygenase activities were determined in human liver microsomal preparations. The results of correlation analysis suggest that: there are important variations in the amounts of the three cytochrome P-450 isozymes measured, particularly P-450(8) and P-450(9); aldrin epoxidase, d-benzphetamine N-demethylase, and S-warfarin 4-hydroxylase activities are linked to cytochrome P-450(5); aryl hydrocarbon (benzo(a)pyrene) hydroxylase and 4-nitroanisole-O-demethylase activities are linked to P-450(8); hydroxylations at the 4'-, 6-, 7-, and 8-positions of R-warfarin are closely linked to each other but are not correlated with other measured monooxygenase activities or P-450 isozyme levels; and P-450(9) is not related to any of the catalytic activities tested. Thus, certain monooxygenase activities can be attributed to specific cytochrome P-450 isozymes. This approach should be useful in suggesting the roles of different cytochromes P-450 in drug metabolism in man which can be further examined using in vitro and in vivo methods. [less ▲]

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See detailComparison of MRI images obtained at 7T in a dog to macroscopic and histopathological examination
Van Thielen, B.; Visser, F.; Denolin, V. et al

Poster (2010, July 20)

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See detailComparison of muscle energetics during voluntary and electrically induced contractions in humans
Vanderthommen, Marc ULg; Duteil, S.; Wary, C. et al

in Rainoldi, A.; Minetto, M. A.; Merletti, R. (Eds.) Biomedical engineering in exercise and sports (2006)

Detailed reference viewed: 10 (1 ULg)