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See detailAssessment of the NeQuick Model at Mid-latitudes using GPS TEC and Ionosonde Data
Bidaine, Benoît ULg; Warnant, René ULg

in First Colloquium Scientific and Fundamental Aspects of the Galileo Programme (2007, October)

The ionosphere plays a crucial role in Global Navigation Satellite Systems (GNSS) accuracy. In extreme cases, this electrically charged part of the atmosphere can lead to errors in positioning exceeding ... [more ▼]

The ionosphere plays a crucial role in Global Navigation Satellite Systems (GNSS) accuracy. In extreme cases, this electrically charged part of the atmosphere can lead to errors in positioning exceeding 100 $m$. At first approximation, ionospheric effects depend mainly on the total content in free electrons of the ionosphere ("total electron content", TEC). The modelling of the latter parameter reveals thus itself critical in particular for single frequency receivers, the most common ones constituting the mass market. In the framework of GALILEO, the NeQuick model has been chosen to this extent and will be integrated into a global algorithm providing the users with daily updated information. In order to reach the specified correction level, the model itself and its latest evolutions as well as its use for GALILEO are investigated. As a first step in a thorough analysis, we take benefit of ionosonde and GPS TEC data from the Dourbes Geophysical Observatory (Belgium) to study the mid-latitudes. Constraining the model with ionosonde measurements, we first investigate the difference between GPS-derived vertical TEC (vTEC) for Dourbes station and corresponding values from NeQuick for the latest years for solar maximum in 2002 and minimum in 2006. With this approach, we reach residual errors of about 20% RMS for 2002 and 30% for 2006. Through a focusing process, we identify then gradually best and worst months and days for which we observe the evolution between two versions of NeQuick. We highlight among others improvements from the latest modification in the topside formulation which appears clearly in the electron density profiles examined at the end of the assessment. [less ▲]

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See detailAssessment of the new immunological test Hemoblot for detecting occult blood in faeces
Jeanson, Antoinette; Jamart, J.; Maisin, J. M. et al

in European Journal of Cancer Prevention (1994), 3(5), 407-412

Hemoblot, a new immunological faecal occult blood test, produced by Gamma, Angleur, Belgium, was characterized and compared with another immunological test (HemeSelect, SmithKline Diagnostics, USA) and ... [more ▼]

Hemoblot, a new immunological faecal occult blood test, produced by Gamma, Angleur, Belgium, was characterized and compared with another immunological test (HemeSelect, SmithKline Diagnostics, USA) and with a guaiac test (Hemoccult II, SmithKline Diagnostics). The analytical sensitivity of Hemoblot is 0.15 mg haemoglobin/g faeces and the test is specific for human haemoglobin. In addition, 135 symptomatic patients who had to undergo a colonoscopy were tested using the three tests. Two criteria were considered for the analysis: (1) the blood criterion: any pathology likely to cause colorectal or other bleeding; and (2) the precancerous-cancerous criterion: the pathology being either a colorectal polyp > 0.5 cm or a colorectal cancer. Considering both criteria, the sensitivity of Hemoblot was significantly higher than the sensitivity of Hemoccult: 38% and 23%, respectively, for the blood criterion; and 54% and 29% for the precancerous-cancerous criterion. Sensitivity and specificity did not differ statistically between Hemoblot and HemeSelect but Hemoblot was faster and simpler to perform. It could be widely used in mass screening. [less ▲]

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See detailAssessment of the night weather parameters and their use in forecasting model of leaf rust.
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

Conference (2010, August 07)

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See detailAssessment Of The Night Weather Parameters And Their Use In Forecasting Model Of Wheat Leaf Rust.
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

in Phytopathology (2010), (100), 32

A stochastic model was developed to predict the wheat leaf rust (Puccinia triticina Eriks.) severity (percentage of leaf area with symptoms showing uredinia) in four-replicated field experiments located ... [more ▼]

A stochastic model was developed to predict the wheat leaf rust (Puccinia triticina Eriks.) severity (percentage of leaf area with symptoms showing uredinia) in four-replicated field experiments located in three villages (Diekirch district: Reuler; Grevenmacher district: Burmerange and Christnach), representative of the different agroclimatological zones of Luxembourg. The model was elaborated by the analysis of the night weather and leaf rust incidence. Statistical validation using regression analysis reports a strong correlation between the number of hours with specific meteorological conditions and the percentage leaf area covered by brown rust lesions for the two upper and youngest leaves, which are mostly responsible for photosynthesis activity and assimilates production filling the grains. The development of the brown rust requires a period of at least twelve consecutive hours with temperatures between 8 and 16°C and a relative humidity (RH) greater than 60%, with optimal values lying between 12 and 16°C and RH greater than 80%. <br />During the 2004 to 2009 period, at four sites, the linear regression between simulated and observed values for Puccinia triticina was highly significant (P < 0.01) and R2 (coefficient of determination) explained 80 to 85% of the variability. Efforts are now being developed to better define thresholds for fungicide applications and to spatialize the outputs of the model over the entire Luxembourg territory. [less ▲]

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See detailAssessment of the oxidant-antioxidant blood balance in a field exercise test in Standardbred and eventing horses
De Moffarts, Brieuc; Kirschvink, Nathalie; van Erck, Emmanuelle et al

in Equine & Comparative Exercise Physiology (2005), 2(4), 253-261

The aim of this study was to determüie which oxidant-antioxidant blood markers are of interest for a field exercise test (ET) performed on a racetrack. Healthy Standardbred herses (S: n = 12) and healthy ... [more ▼]

The aim of this study was to determüie which oxidant-antioxidant blood markers are of interest for a field exercise test (ET) performed on a racetrack. Healthy Standardbred herses (S: n = 12) and healthy eventing horses (E: n = 12) were investigated. Exercice was monitored by measuring velocity (V), heart rate (HR), and plasma lactate (LA). Whilst maximal LA did sot Biffer (11.8 ± 0.88 mmoll-1), maximal V (S: 12.3 ± 0.17ms-1 versus E: 11.1 ±0.24ms-1, P < 0,05) and final HR (S: 222 ±1 versus E: 203 ± 8 beats min-1, P < 0.03) were significantly différent between groups. Venous was collected at rest (R) prior to ET and The following oxidant-antioxidant markers were detennitted: uric acid (UA), ascorbic acid (AA), alpha-tocopherol (Vit E). vitamin A (Vit A), superoxide cüsmutase (SOB), glutaYhione peroxidase (GPx), glutathione (reduced: GSH and oxidized: GSS(r), glutathione redox ratio (GRR), copper (Cu), zinc (Zn) and sélénium (Se), uxidized proteins (Protox), lipid prrosides (Pool), antioxidant capacity of water-soluble comporteras (ACW) and antioxidant capacity of lipid-soluble components (ACW). The following markers were further determined 15 min (E15) after the ET:UA, ACW; AA, GSH, Proton, Pool, ACL. Standardbreds had significantly higher concentrations of ACW, GSH, ACL and Protox, whilst Se, Zn and SOI) were significantly lover than in eventing horses. Exercice induced a significant increase in ACW and UA. GSH decreaced in eventing horses and Pool significantly decreased in both horse groups. This study describes a field ET of high intensity for Standardbred and eventing horses, which could be performed by all animals tested. By sampling blond al rest and at E15, changes of thé hydrophilic antioxidant defence were partially assessed, whereas no interpretable changes of the lipophilic antioxidants and of oxidation markers (Protox, Pool) could be detected [less ▲]

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See detailThe assessment of the past decades based on modelling and data analysis: some examples
Grégoire, Marilaure ULg; Gorsky, G.; Sesame participants, .

Conference (2010, May)

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See detailAssessment of the present state of the Aral Sea
Mikhailov, V.N.; Kravtsova, V.I.; Gurov, F.N. et al

in Seria 5, Geografia 6 (2001)

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See detailAssessment of the processes controlling the seasonal variations of dissolved inorganic carbon in the North Sea
Bozec, Y.; Thomas, H.; Schiettecatte, L. S. et al

in Limnology & Oceanography (2006), 51(6), 27462762

We used a seasonal North Sea data set comprising dissolved inorganic carbon (DIC), partial pressure of CO2 (pCO2), and inorganic nutrients to assess the abiotic and biological processes governing the ... [more ▼]

We used a seasonal North Sea data set comprising dissolved inorganic carbon (DIC), partial pressure of CO2 (pCO2), and inorganic nutrients to assess the abiotic and biological processes governing the monthly variations of DIC. During winter, advection and air–sea exchange of CO2 control and increase the DIC content in the surface and deeper layers of the northern and central North Sea, with the atmosphere supplying CO2 on the order of 0.2 mol C m22 month21 to these areas. From February to July, net community production (NCP) controls the seasonal variations of DIC in the surface waters of the entire North Sea, with a net uptake ranging from 0.5 to 1.4 mol C m22 month21. During the August–December period, NCP controls the seasonal variations of DIC in the southern North Sea, with a net release ranging from 0.5 to 0.8 mol C m22 month21. Similarly, during the April–August period in the deeper layer of the northern North Sea, the NCP was the main factor controlling DIC concentrations, with a net release ranging from 0.5 to 5.5 mol C m22 month21. In the surface layer of the North Sea, NCP on the basis of DIC was 4.3 6 0.4 mol C m22 yr21, whereas, NCP on the basis of nitrate was 1.6 6 0.2 mol C m22 yr21. Under nutrient-depleted conditions, preferential recycling (extracellular) of nutrients and intracellular mechanisms occurred and were responsible for the non-Redfield uptake of DIC versus nitrate and phosphate. [less ▲]

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See detailAssessment of the risk of cardiovascular diseases in women with increased risk of osteoporosis
Tancredi, Annalisa ULg; Bosio-Le Goux, B.; Reginster, Jean-Yves ULg

in Osteoporosis International (2003, November), 14(Suppl. 7), 89

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See detailAssessment of the selenium status in cattle herds in Wallonia
Mehdi, Youcef ULg; Dotreppe, Olivier ULg; Robaye, Vincent ULg et al

in 64th Annual Meeting of the European Federation of Animal Science (2013, August 26)

The selenium content is low in the soil of Wallonia, the southern part of Belgium. It is therefore logical that the selenium content in feedstuffs grown in these fields-grass, conserved forages, cereals ... [more ▼]

The selenium content is low in the soil of Wallonia, the southern part of Belgium. It is therefore logical that the selenium content in feedstuffs grown in these fields-grass, conserved forages, cereals and by-products- is also low. A survey was carried on 166 farms in Wallonia. The farms were located in 4 specific agronomy areas- Pays de Herve with mainly pastures (4farms)- Ardennes (a sub-mountainous area and pastures, 24 farms), Hesbays with mainly arable lands (55 farms) and Condroz with both pastures and arable (83 farms) There were herds with dairy cow, herds with beef cow and herds with both types of animals. The average age was 44±15 months for the cows and 18±6 months for the heifers. The blood samples were taken on five healthy animals of each herd, on the end of the winter just before the animals went to pastures. The selenium status was assessed by the activity of the Glutathion peroydase. The selenium status was extremely variable for the different farms of the 4 areas with variation coefficient of 56%. It was in Pays de Herve and in Hesbaye that the average selenium status was the highest at 53 and 56 µg Se/l. By contrast, it was in Ardenne and in Condroz that the status was the lowest, at 39 and 43 µg Se/l. The selenium status was, on the whole, higher in the dairy herds than in the beef herds owing to the higher selenium provision by the mineral mixtures and the compound feedstuffs added to the diet. Assuming that the normal selenium concentration in plasma being 70µg/l, it appeared also that 81% of the individual animals tested were below the normal Se concentration. It can thus be concluded from the present survey that the cattle herds in Wallonia are deficient in selenium. [less ▲]

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See detailAssessment of the traffic induced soil compaction risk
Louvet, Jean-Noël ULg; Verswijvel, Johan; Abroughui, Khaoula et al

Scientific conference (2012, May 15)

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See detailAssessment of the ventilatory response to CO2 in two breeds of calves
Rollin, Frédéric ULg; Desmecht, Daniel ULg; Linden, Annick ULg et al

in Proceedings of the 10th Comparative Respiratory Society Meeting (1991)

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See detailThe assessment of third metacarpal bone speed of sound measurements in young exercising thorougbreds
Carstanjen, B; Langlois, P; Detilleux, Johann ULg et al

in Proceedings of the European Society of the Veterinary Society (ESVOT) (2002)

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See detailAssessment of three ovulation induction protocols in mares (hCG, Buserelin and Crude Equine Gonadotropin)
Mourier, E.; Ponthier, Jérôme ULg; Beckers, Jean-François ULg et al

in Reproduction in Domestic Animals (2007, September), 42(Suppl. 2), 76

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See detailAssessment of topical hypopigmenting agents on solar lentigines of Asian women.
Hermanns, Jean-François ULg; Petit, Ludivine; Pierard, Claudine ULg et al

in Dermatology : International Journal for Clinical & Investigative Dermatology (2002), 204(4), 281-6

BACKGROUND: So-called darkened age spots encompass distinct pathological processes. The efficacy of topical depigmenting agents is difficult to objectivate. OBJECTIVE: To assess the hypopigmenting effect ... [more ▼]

BACKGROUND: So-called darkened age spots encompass distinct pathological processes. The efficacy of topical depigmenting agents is difficult to objectivate. OBJECTIVE: To assess the hypopigmenting effect of three cosmetic formulations using objective biometrological methods. METHODS: 50 women of South-East Asian ancestry were enrolled in this pilot study. They had solar lentigines according to dermoscopic criteria. The lesions were treated by topical hypopigmenting formulations. Products were applied twice daily for 2 or 3 months. Assessments at 1-month intervals were made using narrow-band reflectance spectrophotometry, image analysis of video-recorded ultraviolet light reflection and photodensitometry- and image-analysis-assisted corneomelametry. RESULTS: A 20% azelaic acid formulation and another one containing 5% ascorbyl glucosamine, 1% kojic acid and alpha-hydroxyacid esters appeared inefficacious on solar lentigines. A stabilized soy extract showed a better although modest lightening effect when assessed by corneomelametry. The subclinical or faint mottled skin revealed by ultraviolet light examination better responded (p < 0.05) to treatments. CONCLUSION: Focal epidermal hyperpigmentation is better controlled by topical whitening agents when the increase in melanin content reflects a modest functional hyperactivity of melanocytes. [less ▲]

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See detailAssessment of trophic relationships between symbiotic tropical ophiuroids using C and N stable isotope analysis
Fourgon, Didier; Lepoint, Gilles ULg; Eeckhaut, Igor

in Journal of the Marine Biological Association of the United Kingdom (2006), 86(6), 1443-1447

Analyses of the natural abundance of carbon and nitrogen stable isotopes were performed to investigate the feeding habits of two ophiurolds, Ophiomastix venosa and Ophiocoma scolopendrina, and to assess ... [more ▼]

Analyses of the natural abundance of carbon and nitrogen stable isotopes were performed to investigate the feeding habits of two ophiurolds, Ophiomastix venosa and Ophiocoma scolopendrina, and to assess the potential benefit obtained by the symbiotic Ophiomastix venosa juveniles. A tracer experiment was also carried Out to clarify the contribution of algae to the nitrogen uptake amongst the tested ophiurolds. Our results suggest that Ophiocoma scolopendrina adults occupy a higher position in the food web than Ophiomastix venosa and mainly feed on neuston. In contrast, O. venosa adults feed on the alga Sargassum densifolium, and on organic matter associated with sediment. Free juveniles and symbiotic juveniles of O. venosa have intermediate PC values between both adult species. The high proportion of C-13 in the symbiotic juveniles compared to the one in their conspecific adults indicates that their diet slightly differs from the latter and is closer to that of Ophiocoma scolopendrina. This raises the hypothesis that symbiotic juveniles steal neuston front their associated host, O. scolopendrina. [less ▲]

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See detailAssessment of Ultimate Bending Moment of Ships from a Reliability Point of View, Using Independent Perturbations Method
Toderan, Catalin; Richir, Thomas; Caprace, Jean-David ULg et al

in Network for Integrating Structural Safety, Risk and Reliability (ASRANet) (2006, July)

This paper presents a method to asses hull girder ultimate bending moment distribution, taking into account parameters uncertainty. This method is a part of a research activity carried out at University ... [more ▼]

This paper presents a method to asses hull girder ultimate bending moment distribution, taking into account parameters uncertainty. This method is a part of a research activity carried out at University of Liege. The method is able to compute four statistical moments of ultimate strength distribution: average, standard deviation, skewness and kurtosis. Geometry parameters, material parameters and initial imperfections (initial deflections and residual stresses) are considered as random variables and a distribution is associated to each of them. Ultimate bending moment algorithm is a progressive collapse analysis based on Smith method and associated with the load-end shortening model proposed by Bureau Veritas and Joint Bulker Project Rules (JBP). In order to perform a reliability analysis, this algorithm is coupled with independent perturbations method. The advantage is a lower number of simulations compared to the standard Monte-Carlo procedure and a good use of the initial information that is available. The paper contains also a comparative analysis between the presented method and a linear sensitivity analysis performed by the ISSC 2000 “Ultimate Strength” committee for a VLCC structure. [less ▲]

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