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See detailEvaluation of the pharmaceutical interaction and optimization for the preparation of triple antibiotic paste (TRIMIX)
Chavarria Bolanos, Daniel ULg; Pozos-Guillen, Amaury

Scientific conference (2012, November 07)

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See detailEvaluation of the potential of MODIS satellite data to predict vegetation phenology in different biomes: An investigation using ground-based NDVI measurements
Hmimina, G.; Dufrêne, Eric; Pontailler, J.-Y. et al

in Remote Sensing of Environment (2013), (132), 145-158

Vegetation phenology is the st udy of the timing of seasonal events that are considered to be the result of adaptive responses to climate variations on short and long time scales. In the field of remote ... [more ▼]

Vegetation phenology is the st udy of the timing of seasonal events that are considered to be the result of adaptive responses to climate variations on short and long time scales. In the field of remote sensing of vegetation phenology, phenologicalmetrics are derived fromtime series of optical data. For that purpose, considerable effort has been specifically focused on developing noise reduction and cloud-contaminated data removal techniques to improve the quality of remotely-sensed time series. Comparative studies between time series composed of satellite data acquired under clear and cloudy conditions and fromradiometric data obtainedwith high accuracy fromground-basedmeasurements constitute a direct and effective way to assess the operational use and limitations of remote sensing for predicting the main plant phenological events. In the present paper, we sought to explicitly evaluate the potential use of MODerate resolution Imaging Spectroradiometer (MODIS) remote sensing data for monitoring the seasonal dynamics of different types of vegetation cover that are representative of the major terrestrial biomes, including temperate deciduous forests, evergreen forests, African savannah, and crops. After cloud screening and filtering, we compared the temporal patterns and phenological metrics derived from in situ NDVI time series and from MODIS daily and 16-composite products. We also evaluated the effects of residual noise and the in uence of data gaps in MODIS NDVI time series on the identification of the most relevant metrics for vegetation phenology monitoring. The results show that the in exion points of a model fitted to a MODIS NDVI time series allow accurate estimates of the onset of greenness in the spring and the onset of yellowing in the autumn in deciduous forests (RMSE<oneweek). Phenologicalmetrics identical to those providedwith theMODIS Global Vegetation Phenology product (MDC12Q2) are less robust to data gaps, and they can be subject to large biases of approximately twoweeks or more during the autumn phenological transitions. In the evergreen forests, in situ NDVI time series describe the phenology with high fidelity despite small temporal changes in the canopy foliage. However, MODIS is unable to provide consistent phenological patterns. In crops and savannah, MODIS NDVI time series reproduce the general temporal patterns of phenology, but significant discrepancies appear between MODIS and ground-based NDVI time series during very localized periods of time depending on the weather conditions and spatial heterogeneity within the MODIS pixel. In the rainforest, the temporal pattern exhibited by a MODIS 16-day composite NDVI time series ismore likely due to a pattern of noise in the NDVI data structure according to both rainy and dry seasons rather than to phenological changes. More investigations are needed, but in all cases, this result leads us to conclude that MODIS time series in tropical rainforests should be interpreted with great caution. [less ▲]

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See detailEvaluation of the present and future general circulation over Greenland simulated by the IPCC AR5/CMIP5 GCMs with the help of a circulation type classification
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2011, April 05)

Future projections of the Greenland ice sheet melt are based on General Circulation Model (GCM) simulations. In particular, the reliability of downscaling methods forced by these simulations depends on ... [more ▼]

Future projections of the Greenland ice sheet melt are based on General Circulation Model (GCM) simulations. In particular, the reliability of downscaling methods forced by these simulations depends on the quality of the atmospheric circulation simulated by GCMs. Therefore, it is essential to analyse and evaluate the GCMs modelled general circulation for current climate (1961-1990). Atmospheric circulation type classifications offer a very interesting approach for evaluating the GCM-based circulation at a daily time scale compared to the most used methods based only on monthly means. Indeed, the circulation type classification allows a precise and detailed analysis of each circulation type and so, it gives much more information on the ability of GCMs to simulate the different circulation types and consequently the climatic variability of a region. In fact, exceptional circulation events over Greenland, which cannot be taken into account by the monthly mean approach, have much more impact on the melt than the mean atmospheric state. Thus, an automated correlation-based atmospheric circulation type classification (CTC) is used for evaluating the new GCM outputs (available on http://cmip-pcmdi.llnl.gov/cmip5/) computed for the upcoming IPCC report (AR5). The daily geopotential height at 500 hPa simulations of the GCMs for current climate are compared to the NCEP-NCAR 1 and the ECMWF reanalysis data for the summer months (JJA), when melt is the most important. To achieve this, the classification is first done for the reanalysis data over 1961-1990 and afterwards, the types of the reanalysis based CTC are imposed for classifying the GCM datasets over 1961-1990 (from the historical experiment) to allow a direct type per type comparison based on the frequency distribution of each dataset. This approach also gives the opportunity to study the intraclass repartition differences between the reanalysis and the GCMs. After the evaluation of the GCM simulations for current climate, the future projections driven by RCP concentrations or emissions (2011-2040, 2041-2070 and 2071-2100) from the best matching GCMs are analysed in the same way. For current climate, it clearly appears that only a few GCMs are able to reproduce reliably the variability of the atmospheric circulation over Greenland during summer. The differences of frequency between the GCMs and the reanalysis are mainly due to biases of the geopotential height which is systematically over or underestimated by most GCMs and to the underestimation of the variability of the circulation by most GCMs. For future projections, no new circulation types are detected, but rather a general increase of the mean geopotential height regardless of the circulation type. It is also important to note that for many GCMs, the uncertainty of the current climate simulations (given by the differences of the classification results between the GCM simulations for current climate and the reanalysis data for the same time) are of the same order than the projected changes for future climate. Therefore, these projections may be questionable. [less ▲]

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See detailEvaluation of the present and future general circulation over western Europe simulated by the IPCC AR5/CMIP5 GCMs with the help of a circulation type classification
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Conference (2011, April 08)

Downscaling methods forced by General Circulation Model (GCM) simulations are not able to correct the biases in the general circulation simulated by the GCMs. Moreover, since the GCMs have a coarse ... [more ▼]

Downscaling methods forced by General Circulation Model (GCM) simulations are not able to correct the biases in the general circulation simulated by the GCMs. Moreover, since the GCMs have a coarse spatial resolution, they have difficulties to simulate reliably ground variables like temperature and precipitation which are affected by topography, land use and local features. So, we can attempt that they simulate better the large-scale atmospheric circulation. That is why it is of special interest to evaluate the GCM simulations of atmospheric circulation for current climate by comparing them with the NCEP-NCAR 1 and the ECMWF reanalysis data over 1961-1990. This analysis is done over western Europe for summer (JJA) and winter (DJF) for the GCMs (available on http://cmippcmdi.llnl.gov/cmip5/) proposed by the IPCC for its upcoming report (AR5). The method used is an automated circulation type classification based on the daily geopotential height at 500 hPa. It is a leader-algorithm correlation based method taking part of the COST733CAT classification catalogue. Unlike the usually used methods based on the monthly mean circulation, this approach allows a precise analysis of each circulation type. So, it gives much more information on the ability of the GCMs to simulate the different circulation types and consequently the climatic variability of a region. In order to allow a direct comparison between the GCM simulations and the reanalysis data, the classification is done first only for the reanalysis dataset over 1961-1990. Then, the main types individualised here are imposed for the classification of the GCM outputs. Since the circulation types are the same, the comparison between the datasets can be made on the basis of the differences of the frequency distribution throughout the classes. Moreover, the mean intraclass repartition of the circulation situations may differ from one dataset to another. So, the study of this mean and its standard deviation gives an idea of the differences between the reanalysis and the GCMs within each class. Firstly, this approach is applied to current climate (1961-1990) for evaluating the ability of the GCMs driven by the historical experiment to simulate the climate of the last decades over western Europe. In fact, if one GCM is not able to reproduce reliably the main characteristics of the current climate, its future projections may be questionable. Then, the best matching GCMs are retained and the same approach is applied to the future simulations driven by RCP concentrations or emissions (2011-2040, 2041-2070 and 2071-2100). So, the evolution of the frequency of the circulation types and maybe the appearance of new types can be analysed under climate change conditions. Moreover, it is interesting to compare the uncertainty of the current climate simulations to the projected changes for future climate. If the uncertainty is of the same order or higher than the projected changes, the reliability of the simulations for future climate may be very questionable. [less ▲]

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See detailEvaluation of the Production Performances of an Endangered Local Poultry Breed, the Famennoise
Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg; Farnir, Frédéric ULg et al

in International Journal of Poultry Sciences (2009), 8(4), 389-396

The Famennoise is a Belgian poultry breed which is greatly endangered. Like most of the local breeds in this situation, the Famennoise remains largely unknown and is representative of the continuous loss ... [more ▼]

The Famennoise is a Belgian poultry breed which is greatly endangered. Like most of the local breeds in this situation, the Famennoise remains largely unknown and is representative of the continuous loss of genetic diversity that is threatening the future of animal production. From preliminary results, egg production traits in this breed showed valuable economic assets. The present study is, thus, aimed at assessing its production performances with the prospect that it might be conserved for future valorization. Egg production as well as growth traits were estimated. Both aspects showed exploitable performances. In absence of past selection for these traits, eggs presented a mean weight of 55.433.03 g, so being in the middle class of marketable eggs, a yolk to albumen ratio of 50.75.02%, an eggshell resistance (maximal force of breakage of 36.033.3 N) equal to commercial strains and superior to already valorized local breeds. In broilers, a mean weight 980.6716.62 g was reached at 8 weeks, 1815.9036.55 g at week 12 and 2191.9048.31 g at week 15. The Famennoise is, therefore, suggested for use as a dual-purpose breed with a good potential of selection for both productions. It could further serve in crosses for improvement of commercial strains. In conclusion, it appears to be highly urgent to screen endangered local poultry breeds for economically exploitable traits which would motivate conservation programs of biodiversity, before this extraordinary scientific and economic potential get irremediably lost. [less ▲]

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See detailEvaluation of the promethazine and acepromazine sedative and hemodynamic effects and norepinephrine reversal of acepromazine induced hemodynamic alterations in the standing horse
De Araujo Pequito, Manuel ULg

Doctoral thesis (2015)

Some phenothiazine derivates, such as acepromazine (ACP), have beneficial properties that could be interesting in equine patients with systemic inflammatory diseases where neutrophil activation and ROS ... [more ▼]

Some phenothiazine derivates, such as acepromazine (ACP), have beneficial properties that could be interesting in equine patients with systemic inflammatory diseases where neutrophil activation and ROS production are implicated. Besides, ACP’s vasodilatatory properties can also be of clinical importance in conditions such as acute laminitis or in anaesthetic protocols. However, the vasodilation induced by ACP is contraindicated in horses suffering from hypotension, a typical complication of systemic inflammatory diseases in horses. The sedative effect of ACP can also have an impact on the correct evaluation of the mental state of a horse in intensive care. Hence, it could be important either to select another phenothiazine derivate with the same beneficial effects as ACP, but with fewer undesirable effects, or to create a medication protocol, in which ACP is associated to another molecule, with the purpose of diminishing its undesired effects. Therefore, this work focused on the comparison of the sedative and peripheral hemodynamic effects of ACP and promethazine (PTZ) as well as on the evaluation of the hemodynamic effects of the administration of ACP followed by a norepinephrine (NOR) infusion in the standing healthy horse. To achieve this objective, 3 different studies were designed. The first one focused on the comparison between ACP and PTZ and the two other ones focused on the study of the association between ACP and NOR. In the first experimental protocol, 9 healthy Warmblood horses randomly received either intravenous ACP at 0.1 mg/kg or PTZ at 0.1, 0.2 or 0.3 mg/kg. A sedation score based on clinical examination was recorded, and systolic arterial blood pressure (SAP) was noninvasively evaluated using a Doppler flow detector at the tail, just before and every 15 minutes until 60 minutes after drug injection. Hemodynamics of the median artery of the left forelimb was studied using Doppler ultrasonography just before and 45 minutes after injection of the drug, which allowed calculation of surface (SURF), diameter (DIAM), and circumference (CIRC) of the vessel, as well as peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), volumetric flow (VF), and resistivity index (RI) of the blood flow. In the second experimental protocol, an infusion of NOR at a constant rate of 1 μg/kg/minute for 15 minutes was administered to 5 standing healthy horses 45 minutes (TACP+45) after intravenous injection of ACP at 0.1 mg/kg. Non-invasive SAP and the same hemodynamic parameters than in study 1 were evaluated on the median artery. The SAP was evaluated before, 15, 30, 45 and every 5 minutes during the NOR infusion (TNORa, TNORb, TNORc) from TACP+45 to 60 minutes (TACP+60) after ACP administration and at 5 (TACP+65), 15 (TACP+75), 30 (TACP+90) and 45 (TACP+105) minutes after stopingt the NOR infusion. In the third experimental protocol, 45 minutes after ACP intravenous injection at 0.1 mg/kg, a continuous NOR infusion was performed during 10 minutes at 0.3 μg/kg/min, then 10 minutes at 0.5 μg/kg/min, and finally 10 minutes at 1 μg/kg/min in 5 standing healthy horses. Cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) were measured using lithium dilution (LiDCO). The mean (MAP), systolic and diastolic (DAP) systemic arterial pressures were measured invasively using an anesthesic monitoring system, that also automatically calculated the heart rate (HR). All parameters were measured immediately before ACP administration, 45 minutes after, at the end of each incremental 10 minutes NOR continuous infusion rate (TNOR0.3, TNOR0.5 and TNOR1) and ten minutes after terminating the NOR infusion. Regardless of the used dose, PTZ had lesser sedative and hypotensive effects than ACP at 0.1 mg/kg and did not induce significant variations in SURF, DIAM, CIRC, PSV, EDV, MV, VF, and RI of the studied standing horses. Conversely, the vasodilatory and hypotensive properties of ACP were illustrated by a significant increase in SURF, DIAM, CIRC, PSV, EDV, MV, and VF and a significant reduction of the RI and SAP. Unlike ACP, PTZ did not induce alterations on the morphology of the Doppler waveform. All the ACP-induced hemodynamic alterations, with the exception of PSV and MV were significantly counteracted by the NOR infusion at a constant 1 μg/kg/minute rate, from TNORa to TNORc for EDV, VF, MV and RI, and to TACP+65 for SAP, from TNORb to TACP+90 for CIRC and SURF and to TNORc for DIAM. Besides, although the ACP induced hypotension, no significant changes were observed in the CO, SV, SVR and HR. NOR infusion at incremental doses counteracted the decrease of SAP, from TNOR0.3 to TNOR1, of MAP at TNOR0.3 and TNOR1 and of DAP at TNOR1. After the ending of the infusion, the arterial pressure again dropped significantly, the CO and HR increased non significantly, and the SVR decreased non significantly. PTZ appears to have less sedative and peripheral vasodilator effects than ACP, thus it could be safer than ACP in patients suffering from hypotension. The results also demonstrate that a NOR infusion can reverse ACP’s vasodilatory effects, restoring hemodynamic parameters and blood pressure in horses. The studied NOR infusion proved hence to be useful in horses suffering from vasodilation and hypotension, as it reverted the hemodynamic alterations induced by ACP. [less ▲]

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See detailEvaluation of the pulmonary inflammation and bronchial hyperresponsiveness in healthy mice induced by inhaled cyclodextrins
Guéders, Maud ULg; Bertholet, P.; Barillaro, Valery et al

in Journal of inclusion Phenomena and Macrocyclic Chesmistry (2005)

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See detailEvaluation of the pulmonary inflammation and the bronchial hyperresponsiveness in healthy mice induced by inhaled cyclodextrins
Guéders, Maud ULg; Bertholet, Pascal; Barillaro, Valery et al

Conference (2004, May)

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See detailEvaluation of the quantitative performances of Supercritical Fluid Chromatography : from method development to validation
Dispas, Amandine ULg; Lebrun, Pierre ULg; Ziemons, Eric ULg et al

in Journal of Chromatography. A (2014), 1353(Method Validation), 78-88

Recently, the number of papers about SFC increased drastically but scientists did not truly focus their work on quantitative performances of this technique. In order to prove the potential of UHPSFC, the ... [more ▼]

Recently, the number of papers about SFC increased drastically but scientists did not truly focus their work on quantitative performances of this technique. In order to prove the potential of UHPSFC, the present work discussed about the different steps of the analytical life cycle of a method: from development to validation and application. Moreover, the UHPSFC quantitative performances were evaluated in comparison with UHPLC, which is the main technique used for quality control in the pharmaceutical industry and then could be considered as a reference. The methods were developed using Design Space strategy, leading to the optimization of robust method. In this context, when the Design Space optimization shows guarantee of quality, no more robustness study is required prior to the validation. Then, the methods were geometrically transferred in order to reduce the analysis time. The UHPSFC and UHPLC methods were validated based on the total error approach using accuracy profile. Even if UHPLC showed better precision and sensitivity, UHPSFC method is able to give accurate results in a dosing range larger than the 80–120% range required by the European Medicines Agency. Consequently, UHPSFC results are valid and could be used for the control of active substance in a finished pharmaceutical product. Finally, UHPSFC validated method was used to analyse real samples and gave similar results than the reference method (UHPLC). [less ▲]

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See detailEVALUATION OF THE RAPID DETECTION OF ST-17 AND ST-1 GROUP B STREPTOCOCCI USING A MICROFLEX MALDI-TOF MS (BRUKER)
MEEX, Cécile ULg; SACHELI, Rosalie ULg; DESCY, Julie ULg et al

Poster (2014, May)

Objectives Clearly associated to neonatal meningitis, Group B streptococci (GBS) classified as sequence type-17 (ST-17) are defined as the “highly virulent” clone amongst GBS. The aim of this study was to ... [more ▼]

Objectives Clearly associated to neonatal meningitis, Group B streptococci (GBS) classified as sequence type-17 (ST-17) are defined as the “highly virulent” clone amongst GBS. The aim of this study was to evaluate an easy and rapid method, recently described to detect ST-17 and ST-1 GBS, based on distinguishing peak-shifts present on the protein spectrum of these 2 sequence types, using a Microflex (Bruker) matrix-assisted laser desorption/ionization time of flight mass spectrometer (MALDI-TOF MS). Methods This study was performed on 67 multi locus sequence typed (MLST) GBS originated from the Belgian and Czech National Reference Centers, including 18 ST-17 and 16 ST-1. After culture on blood agar, an ethanol/formic acid extraction was performed on each strain. Each extract was spotted once on a target plate, overlaid with 1 µl alpha-cyano-4-hydroxycinnamic acid matrix and further analysed by a Microflex MALDI-TOF MS. One spectrum per isolate was recorded, 240 laser shots being recorded for each spectrum. The spectra were further analysed using a Bruker prototype software, and 2 logarithmic values, one for ST-17 and one for ST-1, calculated from the intensities of the present and absent peaks, were obtained for each strain. If >0, this value indicated the presence of the specific sequence type. In a second step, the test was repeated on each strain with discordant result when compared with MLST. Results Compared with MLST method, the first analysis of the strains gave poor results, leading to very low sensitivities (77.8% for ST-17 and 50% for ST-1) but rather good specificities (85.7% for ST-17 and 98.0% for ST-1). After repeating the analysis on the strains with discordant result, sensitivity, 100% and 93.8%, and specificity, 87.8% and 98.0%, for ST-17 and ST-1 respectively were highly improved. Conclusion Since ST-17 and ST-1 GBS both show distinguishing peak-shifts on their protein spectrum, as described by Lartigue et al., the distinction of these 2 sequence types is now possible by MALDI-TOF MS. To our knowledge, this study is the first describing this application on a Microflex MS using a software to classify the strains. The observed results are promising but, given to the variability of the logarithmic value given by the software, the need to perform several measures on a same strain seems to be essential. After optimization of the analysis procedure, this rapid, easy and cheap method could be used to precociously detect ST-17 among GBS isolated from prenatal screenings, allowing a better follow up of the colonized mothers and a closer monitoring of their newborns. We would like to thank the Bruker Company which allowed us to evaluate the prototype software they have developed. [less ▲]

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See detailEvaluation of the regional climate model WRF over Svalbard
Lang, Charlotte ULg; Fettweis, Xavier ULg; Doutreloup, Sébastien ULg et al

Poster (2012, April 24)

It is well known that high latitude zones are very sensitive to climate change. As a result of global warming, ice sheet melting has increased which in turn has an influence on climate through ... [more ▼]

It is well known that high latitude zones are very sensitive to climate change. As a result of global warming, ice sheet melting has increased which in turn has an influence on climate through modifications of the thermohaline circulation, feedback of ice albedo, sea level rise, … Svalbard is an archipelago between 74 and 81°lat N and 60 percent of its area (62 248 km2) is covered with glaciers and ice sheets. The impact of global warming on the Svalbard cryosphere can be estimated with climate models. However, we need to use regional climate models as they offer the possibility of a higher resolution than general circulation models. We have ran two regional climate models (MAR and WRF) at a 10-kilometre resolution between 2006 and 2010 over Svalbard and compared their simulated climate to near surface measurements at several weather stations through the archipelago in order to determine which one of them could best represent the Svalbard climate. [less ▲]

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