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See detailMicrowave-assisted transformations of carbohydrates
Richel, Aurore ULg; Wathelet, Jean-Paul ULg; Paquot, Michel ULg

in SciTopics / Research Summaries by Experts (2010)

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See detailMicrowave-Enhanced Ruthenium Catalysed Atom Transfer Radical Additions
Richel, Aurore ULg; Leclerc, Alain; Demonceau, Albert ULg et al

Poster (2005)

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See detailMicrowave-enhanced ruthenium-catalysed atom transfer radical additions
Borguet, Yannick ULg; Richel, Aurore ULg; Delfosse, Sbastien et al

in Tetrahedron Letters (2007), 48(36), 6334-6338

The first monomode microwave-assisted atom transfer radical additions (ATRA) of carbon tetrachloride to various olefins were successfully performed, affording the adducts with almost quantitative yields ... [more ▼]

The first monomode microwave-assisted atom transfer radical additions (ATRA) of carbon tetrachloride to various olefins were successfully performed, affording the adducts with almost quantitative yields in less than 10 min at 160 'C. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 39 (17 ULg)
See detailMicrowave-treatment of frozen wood packaging material
Henin, Jean-Marc; Bauduin, Aline; Leyman, Michaël ULg et al

Conference (2012, July 12)

As part of the wood packaging material (WPM) regulation in international trade, the dielectric heating (DH) is soon to be included in ISPM15 (IPPC 2009) as an approved phytosanitary treatment. It has been ... [more ▼]

As part of the wood packaging material (WPM) regulation in international trade, the dielectric heating (DH) is soon to be included in ISPM15 (IPPC 2009) as an approved phytosanitary treatment. It has been considered that when using dielectric radiation (i.e. microwaves or radiofrequencies), reaching 60°C or more throughout the entire profile of the wood during at least 60s (i.e. 60°C/60s) ensures the eradication of any noxious organism present in the wood. Regarding the treatment itself, the main requirements mentioned in the draft of ISPM15 Annex 1 (IPPC 2011) concern the way to achieve “uniformity of heating” as well as the treatment duration, which must not exceed 30min. Concerning wood characteristics, the only restriction to the DH concerns the thickness of the wood pieces, which must not exceed 20cm; no other restriction exists regarding wood moisture content, density or initial temperature. As reported in the draft of ISPM15 Annex 1, it is generally considered that “when using microwaves as a heating source, the coldest part of the wood is the surface”. This statement implies that achieving 60°C (or more) during 60s at the surface of the wood should guarantee compliance with IPPC requirements (i.e. 60°C throughout the profile of the wood). However, since ice and liquid water exhibit very different properties towards microwaves, initially frozen wood (9cmX9cm and 17cmX17cm in cross-section) was irradiated in a 28.8 kW microwave oven (2.45GHz) in order to assess whether achieving 60°C/60s at the surface of less than 20cm-thick planks ensures higher core temperatures. The temperature pattern observed after the treatment was compared with the one observed after the treatment of initially thawed wood pieces. It was observed that, in some conditions, initially frozen pieces exhibit inside temperature (much) lower than 60°C, despite complying with 60°C/60s all over the surface of the wood. These results show that when wood is heated with microwaves, its coldest part may not be the surface. Our results also strongly suggest that the impact of wood properties on post-treatment temperature pattern should be further investigated in order to better identify the limits of the DH (at least on frozen wood). [less ▲]

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See detailMicrowear and Residue Analysis in Perspective: the contribution of ethnoarchaeological evidence
Rots, Veerle ULg; Williamson, Bonny

in Journal of Archaeological Science (2004), 31

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See detailA micro–macro approach of permeability evolution in rocks excavation damaged zones
Levasseur, Séverine ULg; Collin, Frédéric ULg; Charlier, Robert ULg et al

in Computers & Geotechnics (2013), 49

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress ... [more ▼]

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress perturbation around the excavation could lead to a significant increase of the permeability physically due to diffuse and/or localized microcracks growth in the material. In the present study, we investigate microcracks-induced damage processes together with the subsequent modification in permeability. The proposed approach is based on a homogenization-based upper bound extended to the context of micro-cracked media in presence of initial stress. Application of this approach is done on a borehole excavation problem related to the Selfrac in situ experiments on Opalinus Clay. Although, the model fails to quan-titatively account for the in situ permeability change (which may also originated from existing macro-fractures), its prediction shows a significant evolution of the material permeability around the borehole. This is in qualitative agreement with available data. [less ▲]

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See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mohammed ULg; Beghin, Jérémie ULg; le roux, Gael et al

in Climate of the Past (2013), 9(2889-2928,),

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic peatland. The Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd isotopes ... [more ▼]

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic peatland. The Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd isotopes, were determined by HR-ICP-MS and MC-ICP-MS respectively, along a  6 m peat section covering 5300 years, from 2000 to 7300 cal.BP dated by the 14C method. Changes in REE concentration in the peat correlate with those of Ti, Al, Sc and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Peat humification and testate amoebae were used to evaluate hydroclimatic conditions. The range of dust deposition varied from 0.03 to 4.0 g m-2 yr-1. The highest dust fluxes were observed from 2750 to 2550 cal.BP and from 5150 to 4750 cal.BP and correspond to cold periods. The Nd values show a large variability from -13 to –5, identifying three major sources of dusts: local soils, distal volcanic and desert particles. [less ▲]

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See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mohammed ULg; Fagel, Nathalie ULg; Le Roux, Gael et al

Poster (2012, June 28)

The Misten peat bog representing 7.5 m of peat accumulation in the Hautes-Fagnes Plateau, Belgium, provides a record of Rare Earth Elements (REE) deposition since more than 7000 years. The analyses of REE ... [more ▼]

The Misten peat bog representing 7.5 m of peat accumulation in the Hautes-Fagnes Plateau, Belgium, provides a record of Rare Earth Elements (REE) deposition since more than 7000 years. The analyses of REE and lithogenic element concentrations, as well as the Nd isotopes, were performed by HR-ICP-MS and MC-ICP-MS, respectively in peat layers previously dated by 210Pb and 14C. REE concentration variations in peat samples are correlated with Ti, Zr and Sc that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs [1] and can be used as tracers of dust deposition. Peat humification, C/N ratio, ash content and bulk density were used to evaluate hydroclimatic conditions. The Nd values show large variability, between +1 to –22, identifying three major sources of dusts falling into the peat: local soils, distal volcanic and desert particles. More recently, industrial emissions provide a fourth source of dusts [2], which is also clearly recorded in the last 200 years of the Misten peat profile. [less ▲]

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See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mohammed ULg; Le Roux, Gael; Piotrowska, Natalia et al

Poster (2012, June)

Multi-proxy climate recorded from peatlands have been used to tracer the climate change during the Holocene. The initiation of peatland may be related to a change to colder and or wetter climate, and the ... [more ▼]

Multi-proxy climate recorded from peatlands have been used to tracer the climate change during the Holocene. The initiation of peatland may be related to a change to colder and or wetter climate, and the variations in peat composition reflect changes in precipitation and temperature. Peat has been used as an archive to reconstruct climate change over the Holocene (e.g., Shotyk et al., 1998; Sapkota et al., 2006). To characterize the climate in Belgium, a 570 cm-long core from Misten peat bog was studied. Several radiocarbon ages allow to define an accurate age model, the peat core represents 5500 years of record. The analyses of REE and lithogenic element contents, as well as the Nd isotopes, were performed by HR-ICP-MS and MC-ICP-MS. Peat humification, C/N ratio, ash content and bulk density were used to evaluate local hydroclimatic conditions. The dust deposition ranges from 0.03 to 4 g m -2 yr -1. As a first observation the highest rates of atmospheric dust deposition correspond to cold periods. The Nd values show large variability, between +1 to –22, identifying three major sources of dusts falling into the peat: local soils, distal volcanic and desert particles. Further studies are in progress to better identify the main forcing factor on the evolution of the atmospheric dust deposition over the Holocene. [less ▲]

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See detailMid infrared and fluorescence spectroscopies coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems
Karoui, Romdhane; Hammami, Moncef; Rouissi, Hamadi et al

in Food Chemistry (2011), 127(2), 743-748

Mid infrared spectroscopy (MIR) combined with multivariate data analysis was used to discriminate between ewes milk samples according to their feeding systems (controls, ewes fed scotch bean and ewes fed ... [more ▼]

Mid infrared spectroscopy (MIR) combined with multivariate data analysis was used to discriminate between ewes milk samples according to their feeding systems (controls, ewes fed scotch bean and ewes fed soybean). The MIR spectra were scanned throughout the first 11 weeks of the lactation stage. When factorial discriminant analysis (FDA) with leave one-out cross-validation was applied, separately, to the three spectral regions in the MIR (i.e. 3000-2800, 1700-1500 and 1500-900 cm(-1)), the classification rate was not satisfactory. Therefore, the first principal component (PCs) scores (corresponding to 3, 10 and 10 for, respectively, the 3000-2800, 1700-1500 and 1500-900 cm(-1)) of the principal component analysis (PCA) extracted from each of the data sets were pooled (concatenated) into a single matrix and analysed by FDA. Correct classification amounting to 71.7% was obtained. Finally, the same procedure was applied to the MIR and fluorescence data sets and 98% of milk samples were found to be correctly classified. Milk samples belonging to control and soybean groups were 100% correctly classified. Regarding milk samples originating from the scotch bean group, only 2 out of 33 samples were misclassified. It was concluded that concatenation of the data sets collected from the two spectroscopic techniques is an efficient tool for authenticating milk samples according to their feeding systems, regardless of the lactation stage. (C) 2011 Published by Elsevier Ltd. [less ▲]

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See detailMid-Famennian cryptalgal-sponge crinoidal mud mounds and oolitic ironstones of the Limbourg-Dolhain area (Verviers Synclinorium, Eastern Belgium): Stop 2.
Dreesen, Roland; Marion, Jean-Marc ULg; Poty, Edouard ULg

Scientific conference (1993, June 09)

After the mass extinction of colonial reefs in the Ardennes at the Frasnian-Famennian boundary, (crypt)algal-sponge-crinoidal mud mounds suddenly appeared during the mid-Famennian time (Early-Late ... [more ▼]

After the mass extinction of colonial reefs in the Ardennes at the Frasnian-Famennian boundary, (crypt)algal-sponge-crinoidal mud mounds suddenly appeared during the mid-Famennian time (Early-Late marginifera Zone) in the Verviers Synclinorium (Eastern Belgium). These carbonate buildups represent the first reported occurrence of mud mounds in the latest Upper Devonian of Western Europe. The mounding sites for the mud mounds (locally known as "the Marbre rouge à crinoïdes de Baelen") are developed on a block-faulted basement. [less ▲]

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See detailMid-FIR Properties of ELAIS Sources
Marquez, I.; Masegosa, J.; Morel, Thierry ULg et al

in The Promise of the Herschel Space Observatory (2001, July 01)

We present the properties of all the galaxies detected by ISO at 7, 15 and 90 microns in ELAIS northern fields. The spectral energy distribution (SED) of those 20 galaxies with IRAS detections can ... [more ▼]

We present the properties of all the galaxies detected by ISO at 7, 15 and 90 microns in ELAIS northern fields. The spectral energy distribution (SED) of those 20 galaxies with IRAS detections can generally be well fitted by a predominant cirrus component plus a modest starburst contribution. Follow-up spectroscopy has shown that all the objects are emission-line galaxies but without a very intense star formation event. Most of the galaxies analyzed by means of optical R band photometry result to host an important exponential disk component, in good agreement with the SED IR modelling. We note that galaxies with morphological signs of perturbations seem to show slightly higher f[SUB]15[/SUB]/f[SUB]6.7[/SUB] ratios, indicating that star formation could be more important in them. One of the objects is a broad-line, radio-quiet quasar at z=1.099; its spectral energy distribution indicates that it is a hyperluminous infrared galaxy (HLIG), the first HLIG detected in the ELAIS areas. [less ▲]

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See detailMid-infrared prediction of bovine milk fatty acids across multiple breeds, production systems, and countries
Soyeurt, Hélène ULg; Dehareng, ; Gengler, Nicolas ULg et al

in Journal of Dairy Science (2011), 94

Increasing consumer concern exists over the relationship between food composition and human health. Because of the known effects of fatty acids on human health, the development of a quick, inexpensive ... [more ▼]

Increasing consumer concern exists over the relationship between food composition and human health. Because of the known effects of fatty acids on human health, the development of a quick, inexpensive, and accurate method to directly quantify the fatty acid (FA) composition in milk would be valuable for milk processors to develop a payment system for milk pertinent to their customer requirements and for farmers to adapt their feeding systems and breeding strategies accordingly. The aim of this study was (1) to confirm the ability of mid-infrared spectrometry (MIR) to quantify individual FA content in milk by using an innovative procedure of sampling (i.e., samples were collected from cows belonging to different breeds, different countries, and in different production systems); (2) to compare 6 mathematical methods to develop robust calibration equations for predicting the contents of individual FA in milk; and (3) to test interest in using the FA equations developed in milk as basis to predict FA content in fat without corrections for the slope and the bias of the developed equations. In total, 517 samples selected based on their spectral variability in 3 countries (Belgium, Ireland, and United Kingdom) from various breeds, cows, and production systems were analyzed by gas chromatography (GC). The samples presenting the largest spectral variability were used to calibrate the prediction of FA by MIR. The remaining samples were used to externally validate the 28 FA equations developed. The 6 methods were (1) partial least squares regression (PLS); (2) PLS + repeatability file (REP); (3) first derivative of spectral data + PLS; (4) first derivative + REP + PLS; (5) second derivative of spectral data + PLS; and (6) second derivative + REP + PLS. Methods were compared on the basis of the crossvalidation coefficient of determination (R2cv), the ratio of standard deviation of GC values to the standard error of cross-validation (RPD), and the validation coefficient of determination (R2v). The third and fourth methods had, on average, the highest R2cv, RPD, and R2v. The final equations were built using all GC and the best accuracy was observed for the infrared predictions of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C18:1 trans, C18:1 cis-9, C18:1 cis, and for some groups of FA studied in milk (saturated, monounsaturated, unsaturated, short-chain, medium-chain, and long-chain FA). These equations showed R2cv greater than 0.95. With R2cv equal to 0.85, the MIR prediction of polyunsaturated FA could be used to screen the cow population. As previously published, infrared predictions of FA in fat are less accurate than those developed from FA content in milk (g/dL of milk) and no better results were obtained by using milk FA predictions if no corrections for bias and slope based on reference milk samples with known contents of FA were used. These results indicate the usefulness of equations with R2cv greater than 95% in milk payment systems and the usefulness of equations with R2cv greater than 75% for animal breeding purposes. [less ▲]

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See detailMid-infrared prediction of cheese yield from milk and its genetic variability in first-parity cows
Colinet, Frédéric ULg; Troch, Thibault ULg; Vanden Bossche, Sandrine et al

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

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See detailMid-infrared prediction of cheese yield from milk and its genetic variability in first-parity cows
Colinet, Frédéric ULg; Troch, Thibault ULg; Vanden, Bossche et al

Conference (2013, August 29)

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See detailMid-infrared prediction of milk titratable acidity and its genetic variability in first-parity cows
Colinet, Frédéric ULg; Vanlierde, Amélie ULg; Vanden Bossche, sandrine ULg et al

in Book of Abstracts of the 63rd Annual Meeting of the European Federation of Animal Science (2012, August)

Coagulation of milkhas a direct effect on cheese yield. Among several parameters, titratable acidity of milk (TA) influences all the phases of milk coagulation. In order to study the genetic variability ... [more ▼]

Coagulation of milkhas a direct effect on cheese yield. Among several parameters, titratable acidity of milk (TA) influences all the phases of milk coagulation. In order to study the genetic variability of this trait on a large scale, mid-infrared (MIR) chemometric methods were used to predict TA. A total of 507 milk samples collected in the Walloon Region of Belgium from individual cows were analyzed using a MIR spectrometer. TA was recorded as Dornic degree. An equation to predict TA from milk MIR spectrum was developed using partial least squared regression after a first derivative pre-treatment applied to the spectra to correct the baseline drift. During the calibration process, 45 outliers were detected and removed from the calibration set. The TA mean of the final calibration set was 16.62 (standard deviation (SD) = 1.80). The coefficient of determination (R²) was 0.82 for the calibration with a standard error (SE) of 0.76. A cross-validation (cv) was performed (R²cv = 0.81 with SEcv = 0.80). This equation was then applied on the spectral database generated during the Walloon routine milk recording. The variances components were estimated by REML using single-trait random regression animal test-day model. The dataset used included 33,717 records from 9,191 Holstein first-parity cows; the TA mean was 17.05 (SD = 1.35) and TA ranged from 12.83 to 20.87. Estimated daily heritabilities ranged from 0.43 at 5th day in milk to 0.59 at 215th day in milk indicating potential of selection. Further research will study phenotypic and genetic correlations between TA and milk production traits. [less ▲]

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See detailMid-infrared prediction of milk titratable acidity and its genetic variability in first-parity cows
Colinet, Frédéric ULg; Vanlierde, Amélie ULg; Vanden Bossche, sandrine ULg et al

Conference (2012, August 27)

Coagulation of milkhas a direct effect on cheese yield. Among several parameters, titratable acidity of milk (TA) influences all the phases of milk coagulation. In order to study the genetic variability ... [more ▼]

Coagulation of milkhas a direct effect on cheese yield. Among several parameters, titratable acidity of milk (TA) influences all the phases of milk coagulation. In order to study the genetic variability of this trait on a large scale, mid-infrared (MIR) chemometric methods were used to predict TA. A total of 507 milk samples collected in the Walloon Region of Belgium from individual cows were analyzed using a MIR spectrometer. TA was recorded as Dornic degree. An equation to predict TA from milk MIR spectrum was developed using partial least squared regression after a first derivative pre-treatment applied to the spectra to correct the baseline drift. During the calibration process, 45 outliers were detected and removed from the calibration set. The TA mean of the final calibration set was 16.62 (standard deviation (SD) = 1.80). The coefficient of determination (R²) was 0.82 for the calibration with a standard error (SE) of 0.76. A cross-validation (cv) was performed (R²cv = 0.81 with SEcv = 0.80). This equation was then applied on the spectral database generated during the Walloon routine milk recording. The variances components were estimated by REML using single-trait random regression animal test-day model. The dataset used included 33,717 records from 9,191 Holstein first-parity cows; the TA mean was 17.05 (SD = 1.35) and TA ranged from 12.83 to 20.87. Estimated daily heritabilities ranged from 0.43 at 5th day in milk to 0.59 at 215th day in milk indicating potential of selection. Further research will study phenotypic and genetic correlations between TA and milk production traits. [less ▲]

Detailed reference viewed: 68 (37 ULg)
See detailMid-infrared predictions of cheese yield from bovine milk
Vanlierde, Amélie ULg; Soyeurt, Hélène ULg; Anceau, Christine ULg et al

in Book of Abstracts of the 62nd Annual Meeting of the European Association for Animal Production (2011, August)

Economically, cheese yield (CY) is very important. Todate, empirical or theoretical formulae allow estimating the theoretical CY from milk fat and casein or protein content of milk. It would be ... [more ▼]

Economically, cheese yield (CY) is very important. Todate, empirical or theoretical formulae allow estimating the theoretical CY from milk fat and casein or protein content of milk. It would be interesting to predict CY during milk recording directly without the need to estimate milk components. Through the BlueSel project, 157 milk samples were collected in Wallonia from individual cows and analyzed using a mid-infrared (MIR) MilkoScanFT6000 spectrometer. Individual laboratory cheese yields (ILCY) were determined for each sample and expressed as g of dry coagulum/100 g of milk dry matter. An equation to predict ILCY from MIR was developed using partial least squared regression (Winisi III). A first derivative pre-treatment of spectra was used to correct the baseline drift. To improve the repeatability of the spectral data, a file which contained the spectra of samples analyzed on 5 spectrometers was used during the calibration. During calibration, 23 outliers were detected a nd removed from the calibration set. The ILCY mean of the final calibration set was 63.9% with a SD of 11.2%. The calibration (C) coefficient of determination (R²) was equal to 0.76 with a standard error (SE) of calibration of 5.5%. A full cross-validation (CV) was preformed to assess the robustness. R²cv was 0.72 with a SECV of 6.0%. The similarity between R²c and R²cv as well as between SEC and SECV permits to consider robustness of the developed equation as good. Even if it is planned to improve the equation with additional samples, this first equation will permit to study ILCY in the Walloon dairy cattle. [less ▲]

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See detailMid-infrared predictions of cheese yield from bovine milk
Vanlierde, Amélie ULg; Soyeurt, Hélène ULg; Anceau, Christine ULg et al

Conference (2011, August 31)

Economically, cheese yield (CY) is very important. Todate, empirical or theoretical formulae allow estimating the theoretical CY from milk fat and casein or protein content of milk. It would be ... [more ▼]

Economically, cheese yield (CY) is very important. Todate, empirical or theoretical formulae allow estimating the theoretical CY from milk fat and casein or protein content of milk. It would be interesting to predict CY during milk recording directly without the need to estimate milk components. Through the BlueSel project, 157 milk samples were collected in Wallonia from individual cows and analyzed using a mid-infrared (MIR) MilkoScanFT6000 spectrometer. Individual laboratory cheese yields (ILCY) were determined for each sample and expressed as g of dry coagulum/100 g of milk dry matter. An equation to predict ILCY from MIR was developed using partial least squared regression (Winisi III). A first derivative pre-treatment of spectra was used to correct the baseline drift. To improve the repeatability of the spectral data, a file which contained the spectra of samples analyzed on 5 spectrometers was used during the calibration. During calibration, 23 outliers were detected a nd removed from the calibration set. The ILCY mean of the final calibration set was 63.9% with a SD of 11.2%. The calibration (C) coefficient of determination (R²) was equal to 0.76 with a standard error (SE) of calibration of 5.5%. A full cross-validation (CV) was preformed to assess the robustness. R²cv was 0.72 with a SECV of 6.0%. The similarity between R²c and R²cv as well as between SEC and SECV permits to consider robustness of the developed equation as good. Even if it is planned to improve the equation with additional samples, this first equation will permit to study ILCY in the Walloon dairy cattle. [less ▲]

Detailed reference viewed: 60 (28 ULg)