References of "Brostaux, Yves"
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See detailInfluence of processing parameters on physicochemical properties of low-trans and trans-free puff pastry margarines
Lefebure, Emilie ULg; Ronkart, Sébastien; Brostaux, Yves ULg et al

in LWT - Food Science and Technology (2013), 51(1), 225-232

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See detailDEVELOPMENT OF FROZEN-FRIED YAM SLICES: OPTIMIZATION OF THE PROCESSING CONDITIONS
Toure, Yetioman ULg; Nindjin, Charlemagne; Brostaux, Yves ULg et al

in African Journal of Food, Agriculture, Nutrition and Development (2012), 12(7), 7055-7071

The research performed on yam processing mainly concerns the production of crisps and flour. However, its transformation into deep-frozen French fries does not necessitate any other equipment than those ... [more ▼]

The research performed on yam processing mainly concerns the production of crisps and flour. However, its transformation into deep-frozen French fries does not necessitate any other equipment than those used for potatoes. The industrial process of production of frozen French fries traditionally includes a pre-frying step. These steps contribute to the development of color and crispness, and the oil partially absorbed inhibits dehydration during the freezing step. The aim of this study was to optimize frying conditions of deep-frozen fried yam (Dioscorea cayenensis var Kponan) slices. The effect of pre-frying time and temperature, final frying time and temperature on the oil uptake, texture, dry matter and colour of the fried yam slices has been studied. Frying conditions optimized with Box-Behnken experimental design were short pre-frying and frying conditions at high temperature characterized by pre-frying temperature at 157-170°C during 5-9s and frying temperature at 181-188°C for 2min 15s-2min 30s; or long pre-frying and frying conditions at low temperature characterized by pre-frying temperature at 150-158°C during 10-15s and frying temperature 170-177°C for 3-3min 15s. An adiabatic system was also developed by means of an insulator in which the core temperature of fried yam slices can be maintained constant at about 55°C after 15min of cooling, facilitating texture measurements at constant temperature. The present results may help in choosing the yam slices frying condition to be applied in order to achieve the desirable fried yam slices quality, required for protection against certain diseases like obesity. These models may also provide guidance as to how to control these quality parameters by altering four key environmental factors, pre-frying temperature and time and, final frying temperature and time. This process can also be commercialized and does not necessitate any other cost for equipment than those used for potatoes French fries and might be an interesting way of added value processing for this highly perishable yam tuber. [less ▲]

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See detailAbundance and phenological model of Harmonia axyridis (Coleoptera: Coccinellidae) in field crops
Vandereycken, Axel ULg; Brostaux, Yves ULg; Joie, Emilie ULg et al

Poster (2012, December 07)

The multicolored Asian ladybeetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) was introduced into Western Europe in the late 1990s. This exotic and invasive species is known to thrive ... [more ▼]

The multicolored Asian ladybeetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) was introduced into Western Europe in the late 1990s. This exotic and invasive species is known to thrive principally in shrubs and arboreal habitats. We focus on a phonological model and on annual abundance in various field crops. The abundance of H. axyridis adults and larvae were evaluated during a three-year period, from 2009 to 2011, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. H. axyridis colonizes and reproduces in all four crops studied, with larger densities observed in corn and broad bean. The reproduction of H. axyridis occurs principally in corn and occurred much less in wheat and potato. From 2009 to 2011, abundances of H. axyridis populations were constant except in corn, where the observed densities of all immature stages and adults were higher in 2011 than in 2009. The population dynamics of aphids and H. axyridis were characterized by a symmetric logistic function (S-shape) based on the cumulative population size. [less ▲]

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See detailDiagnosing structure and composition typologies in uneven-aged broad-leaved forests: a comparison of classification methods
Bonnet, Stéphanie ULg; Brostaux, Yves ULg; Claessens, Hugues ULg et al

Poster (2012, September)

Structure and composition of forest stands are crucial factors for forest planning and biodiversity management. In Belgium, typologies of structure and composition exist to support planning in uneven-aged ... [more ▼]

Structure and composition of forest stands are crucial factors for forest planning and biodiversity management. In Belgium, typologies of structure and composition exist to support planning in uneven-aged broadleaved forests (typically dominated by oak and beech). The principle of these typologies is to classify irregular stands with the percentage of small, medium, large, and very large trees (regarding dbh), and the percentage of basal area of oak and beech. This paper investigates the potential of LiDAR data processed with classification methods (k-nn, K-Means, CART, etc.) to allocate a forest structure and composition type. For this purpose several supervised and unsupervised classification methods are compared, as well as the impact of leaf-on (summer) and leaf-off (winter) data to discriminate the forest types. [less ▲]

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See detailHoneydew volatile emission acts as a kairomonal message for the Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae)
Leroy, Pascal; Heuskin, Stéphanie ULg; Sabri, Ahmed ULg et al

in Insect Science (2012), 19(4), 498-506

The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attractant for many aphid predators ... [more ▼]

The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attractant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-1-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vicia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds (3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene) were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonenewas the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals aswell as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis. [less ▲]

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See detailIdentification of bacteria community associated with earthworm gut
Lemtiri, Aboulkacem ULg; Alabi, Taofic; Bodson, Bernard ULg et al

Poster (2012, July 26)

The role of earthworms in soil fertility and transformation of organic waste was regulary cited to be of first importance. Associated to these macro-invertebrates, a large diversity of micro-orgnisms are ... [more ▼]

The role of earthworms in soil fertility and transformation of organic waste was regulary cited to be of first importance. Associated to these macro-invertebrates, a large diversity of micro-orgnisms are found indirectly in their closed environment or directly in their gut. Functional aspects of these interactions and symbiosis in relation with soil characteristics and fertility rates are poorly developed. Here, the micro-organisms diversity and potential related functions of earthworm gut were investigated using a proteiomic approach for both protein and micro-organism identifications. Microbial community investigation was detected by proteomic approach based on bidimensional electrophoresis coupled with mass spectrometry using Matrix Assisted Laser Desorption Ionisation – time of flight (Maldi-Tof). Diversity of gut associated bacterial communities was discussed. Indeed, application of particular crop production practices such as crop residue management at the field level could regulate the gut bacterial communities in earthworm but also microbials in soils. Agricultural systems had to consider the microbial and associated organisms in the soil to enhance fertlility and crop production in sustainable ways. [less ▲]

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See detailImpact of soil management on earthworm diversity according to differential plowing and plant residue incorporation
Lemtiri, Aboulkacem ULg; Alabi, Taofic; Zirbes, Lara ULg et al

Poster (2012, July 02)

Earthworms are largely distributed in terrestrial ecosystems and their abundance and diversity in soils are significantly affected by biotic (macro- and micro-organisms) and abiotic factors: soil ... [more ▼]

Earthworms are largely distributed in terrestrial ecosystems and their abundance and diversity in soils are significantly affected by biotic (macro- and micro-organisms) and abiotic factors: soil properties (pH, texture, structure…); agricultural management system and climate change. Here, tillage effect of earthworm population combined with crops residual management was investigated and correlated with soils properties. From wheat experimental field plots, the diversity of earthworm according to the field crop management was assessed. Application of particular crop production practices such as the integration of different levels of crop residues, diverse parts of wheat straws, at the field level regulate earthworm diversity and population abundance. Indeed, tillage reduced earthworm population with a 35% rate also corresponding to changes in soil properties. Agricultural practices had to be adapted to include consideration on macro-invertebrate abundance and diversity to maintain efficient soil fertility and allow sustainable crop production [less ▲]

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See detailComparative Chemical and Molecular Variability of Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Ylang-Ylang) in the Western Indian Ocean Islands: Implication for Valorization
Benini, Céline ULg; Mahy, Grégory ULg; Bizoux, Jean-Philippe ULg et al

in Chemistry & Biodiversity (2012), 9(7), 13891402

Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite ... [more ▼]

Cananga odorata (Lam.) Hook.f. Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite its economic and social importance, very little information is available on its variability and the possible factors causing it. Therefore, the relationship between the genetic structure, revealed by amplified fragment length polymorphism (AFLP), and the essential oil chemical composition, determined by GC/MS analysis, of ylang-ylang grown in semi-managed systems in three Indian Ocean islands (Grande Comore, Mayotte, and Madagascar) was investigated. Our results revealed a low genetic variation within plantations and contrasted situations between islands. Variations of the chemical composition could be observed within plantations and between islands. The genetic differentiation pattern did not match the observed pattern of chemical variability. Hence, the chemical variation could not be attributed to a genetic control. As Grande Comore, Madagascar, and Mayotte present different environmental and agronomic conditions, it can be concluded that the influence of these conditions on the ylang-ylang essential oil composition is consistent with the patterns observed. Finally, several strategies were proposed to valorize the chemical composition variations. [less ▲]

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See detailFlexible aggregative behavior of Harmonia axyridis according to the freshness of area marking in overwintering sites
Durieux, Delphine ULg; Fischer, Christophe ULg; Fassotte, Bérénice ULg et al

Poster (2012, July)

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), aggregates inside dwellings and buildings during winter to survive cold. This adaptive behavior causes annoyances ... [more ▼]

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), aggregates inside dwellings and buildings during winter to survive cold. This adaptive behavior causes annoyances to the occupants because of their large number and the induction of allergic reactions. Although this species has aroused a great interest these last years, the factors involved in the selection of its overwintering sites remain misunderstood. The work presented herein was oriented to the study of the non-volatile chemical compounds involved in this aggregation behavior. Chemical analyses revealed the occurrence, in aggregation sites, of an area marking made up of saturated and unsaturated hydrocarbons. Behavioral investigations demonstrated that H. axyridis preferentially aggregates in sites previously marked by congeners, indicating the retention potential of this blend on overwintering individuals. In the second instance, the same analyses were performed on an area marking aged of one year. The chemical investigations showed that only saturated hydrocarbons can still be detected after that period of time but the remaining blend does not induce aggregation anymore. This difference of response according to the freshness of the area marking suggests that this species would not be prisoner of the marking previously deposited on the substrate if the surrounding has changed and the site is not suitable anymore. [less ▲]

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See detailCurrent Pericopsis elata (Fabaceae) patches in southeastern Cameroon: remnants of a long and rich Human-rainforest relationship?
Bourland, Nils ULg; Cerisier, François; Livingstone Smith, Alexandre et al

Poster (2012, June 23)

Pericopsis elata is one of the most valuable African timber species. This IUCN Red Listed tree suffers from a lack of regeneration, thus its current presence provokes questioning. Our work aimed at ... [more ▼]

Pericopsis elata is one of the most valuable African timber species. This IUCN Red Listed tree suffers from a lack of regeneration, thus its current presence provokes questioning. Our work aimed at understanding its origins so as to help securing its future. This study, lead away from engineering works, was conducted in four different sites located within the natural distribution area of the species and taking into account the different growing conditions were the species occurs. Our observations are based on an analysis of charcoal elements and pottery fragments discovered in subsurface layers of soils as well as current botanical and pedological surveys. Evidence of past human activities we found led to the assumption that this part of the Congo Basin was much more inhabited than previously thought. Some of the results obtained for P. elata could apply for other long lived light demanding species growing in the same environment [less ▲]

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See detailFactors involved in the aggregation of Harmonia axyridis Pallas
Durieux, Delphine ULg; Fischer, Christophe ULg; Deneubourg, Jean-Louis et al

Conference (2012, May 22)

In order to survive cold winters, the invasive multicoloured Asian ladybeetle, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) forms large aggregations in dwellings to overwinter. The factors ... [more ▼]

In order to survive cold winters, the invasive multicoloured Asian ladybeetle, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) forms large aggregations in dwellings to overwinter. The factors involved in the selection of aggregation sites remain misunderstood. The work presented herein focussed on the study of the chemical compounds involved in this phenomenon. Chemical and behavioural analyses highlighted that long-chain hydrocarbons lead congeners towards aggregation sites and ensure the cohesion of the cluster. Subsequently, physical factors were investigated. We studied the influence of (1) the density of individuals and (2) the quality of available shelters on H. axyridis decision to settle and aggregate under shelters. A binary choice experiment conducted in laboratory showed that the multicoloured Asian ladybeetles present a permanent aggregative behaviour, even during non-wintering conditions. These experiments also highlighted the existence of social interactions between individuals. All these results contribute to improve knowledge of this behaviour in H. axyridis and could be used in the design of species-specific traps in order to control infestations in dwellings. [less ▲]

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See detailA Semiochemical Slow-release Formulation in a Biological Control Approach to Attract Hoverflies
Heuskin, Stéphanie ULg; Lorge, Stéphanie ULg; Leroy, Pascal ULg et al

in Journal of Environment and Ecology (2012), 3(1), 72-85

E-β-Farnesene, the alarm pheromone of many aphid species, and E-β-caryophyllene are considered as two sesquiterpenes attractive for aphid predators, among which Syrphidae species. Both compounds were ... [more ▼]

E-β-Farnesene, the alarm pheromone of many aphid species, and E-β-caryophyllene are considered as two sesquiterpenes attractive for aphid predators, among which Syrphidae species. Both compounds were formulated in alginate gel beads as slow-release devices in a biological control approach against aphids. Semiochemical diffusion from beads was studied in the laboratory according to abiotic parameters. Efficiency of formulations as hoverfly attractant was demonstrated in field experiments from June to August 2009. The diffusion of semiochemicals from alginate bead formulations was principally limited by high values (>85%) of relative humidity in the air. Temperature also impacts the release of volatile compounds. In field experiments, these two abiotic factors were supposed to highly condition the trapping of hoverflies. These field trappings demonstrated the efficiency of both semiochemical formulations compared to control (formulation without semiochemical) to catch females of Syrphidae during three months. [less ▲]

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See detailCould current Pericopsis elata (Fabaceae) patches in southeastern Cameroon be reasonably linked to past anthropogenic activities ?
Bourland, Nils ULg; Cerisier, François ULg; Livingstone Smith, Alexandre et al

Poster (2012, March 01)

Pericopsis elata is one of the most valuable African timber species. This IUCN Red Listed tree suffers from a lack of regeneration, thus its current presence provokes questioning. Our work aimed at ... [more ▼]

Pericopsis elata is one of the most valuable African timber species. This IUCN Red Listed tree suffers from a lack of regeneration, thus its current presence provokes questioning. Our work aimed at understanding its origins so as to help securing its future. This study, lead away from engineering works, was conducted in four different sites located within the natural distribution area of the species and took into account the different growing conditions were the species occurs. Our observations were based on an analysis of charcoal elements and pottery fragments discovered in subsurface layers of soils as well as on current botanical and pedological surveys. Discovered evidence of past human activities led to the assumption that this part of the Congo Basin was much more inhabited than previously thought. Some of the results obtained for P. elata could apply for other long lived light demanding species growing in the same environment. [less ▲]

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See detailSelf-assemblage and quorum in the earthworm Eisenia fetida (Oligochaete, Lumbricidae)
Zirbes, Lara ULg; Brostaux, Yves ULg; Mescher, Mark et al

in PLoS ONE (2012), 7(3), 32564

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See detailModelling realized niche of metallophyte species along copper and cobalt gradients on Katanga copper hills
Boisson, Sylvain ULg; Seleck, Maxime ULg; Guillaume, Arielle et al

Poster (2012, February 10)

In South Central Africa were identified more than 650 plant species tolerant to heavy metals, several of which endemic to Katanga and critically endangered by mining activities. These metallophyte are ... [more ▼]

In South Central Africa were identified more than 650 plant species tolerant to heavy metals, several of which endemic to Katanga and critically endangered by mining activities. These metallophyte are distributed over a hundred hills containing high copper and cobalt concentrations (20 to 10000 mg/kg for copper and 2 to 1000 mg/kg for cobalt). To understand the response of metallophyte to heavy metals, the ecological niches of 80 cupro-cobaltophytes were modeled with general additive models (GAM). Results show that (1) three groups of species were identified according to their optimum along a metal concentrations gradient and (2) a positive relationship exists between niche amplitude and optimum copper concentration. [less ▲]

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See detailDépenses en viande par les ménages belges en 2008
Ferrandis Vallterra, Salvador ULg; Brostaux, Yves ULg; Claustriaux, Jean-Jacques ULg et al

Speech (2012)

Analysis of meat expenditure by Belgian households in 2008. Meat expenditure by Belgian households during 2008 is analyzed. Expenditure is extracted from the Belgian Household Budget Survey at the FPS ... [more ▼]

Analysis of meat expenditure by Belgian households in 2008. Meat expenditure by Belgian households during 2008 is analyzed. Expenditure is extracted from the Belgian Household Budget Survey at the FPS Economy, S.M.E.s, Self-employed and Energy. The database also provides sociodemographic information about the households participating in the survey. To explain the observed variability of the meat expenditure based on the explanatory factors available, an analysis of the covariance is performed. The three quantitative factors have a bigger effect on the meat expenditure than the three other qualitative factors. The proportion of meat expenditure variability explained by the explanatory factors of the selected model is 31,41%. [less ▲]

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See detailTables de contingence à trois dimensions : aspects théoriques, applications et analogie avec l'analyse de la variance à trois critères de classification
Claustriaux, Jean-Jacques ULg; Palm, Rodolphe ULg; Ferrandis Vallterra, Salvador ULg et al

in Notes de Statistique et d'Informatique (2012), (1), 19

For contingency table, concepts of independence are not so easy to understand in statistical practice. So, theoretical aspects of the log-linear model are described and applied to a three levels example ... [more ▼]

For contingency table, concepts of independence are not so easy to understand in statistical practice. So, theoretical aspects of the log-linear model are described and applied to a three levels example; an analogy with analysis of variance is also established. [less ▲]

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See detailTesting semiochemicals from aphid, plant and conspecific: attraction of Harmonia axyridis
Leroy, Pascal ULg; Schillings, Thomas ULg; Farmakidis, Julien ULg et al

in Insect Science (2012), 19

Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the ... [more ▼]

Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind-tunnel experiments, semiochemicals from aphids [Z,E-nepetalactone, (E)-β-farnesene, α-pinene and β-pinene], from coccinellids [(-)-β-caryophyllene] and from the nettle Urtica dioica L. were envisaged as potential attractants. The nettle volatile compounds [(Z)-3-hexenol and (E)-2-hexenal] were extracted using a Clevenger Apparatus® and identified by headspace-GC-MS. The main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while (-)-β-caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the (Z)-3-hexenol oriented both males and females to the odour source. The (E)-2-hexenal was showed to have no effect on females even if this green leaf volatile attracted males. This study highlighted that some semiochemicals from aphids and from nettle extracts orientated the harlequin ladybird H. axyridis. These volatile compounds could certainly help for an efficient biological control approach against this invasive specie. [less ▲]

Detailed reference viewed: 108 (48 ULg)