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See detailImpacts of androgenic and antiandrogenic substances on the freshwater pulmonate gastropod Lymnaea stagnalis
Giusti, Arnaud ULg; Lagadic, Laurent; Joaquim-Justo, Célia ULg et al

Poster (2010, May 23)

Knowledge on the impacts of endocrine disruptors on gastropods is scarce and their mechanism of action poorly understood especially the impacts of androgenic and antiandrogenic compounds. In this study ... [more ▼]

Knowledge on the impacts of endocrine disruptors on gastropods is scarce and their mechanism of action poorly understood especially the impacts of androgenic and antiandrogenic compounds. In this study effects of 5 androgenics and antiandrogenics endocrine disruptors were investigated on the reproduction and life traits of the freshwater pulmonate gastropod Lymnaea stagnalis. The chemicals tested were Tributyltin, Cyproterone acetate, Methyltestosterone, Vinclozolin and Fenitrothion. Tributyltin was used as androgenic positive control. The other compounds tested are androgenic and antiandrogenic compounds either steroids or non steroids. Adult snails were exposed to 3 concentrations of each chemical for 30 days. The size and reproductive organs development were monitored throughout exposure. The number of clutches, the number of eggs per clutch were assessed during the first 10 days. The clutches were kept individually in clear water except for the clutches of the eighth day which were divided in two. Half was kept individually in clear water and the other half was individually reared in contaminated water following the same exposure as their parents. The percentage of hatching per clutch of these clutches was measured. The development size, mortality, and development of reproductive organs of the juveniles were assessed until their first clutch was laid. [less ▲]

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See detailImpacts of earthworms on soil components and dynamics. A review
Lemtiri, Aboulkacem ULg; Colinet, Gilles ULg; Alabi, Taofic ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18

Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil ... [more ▼]

Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil fertility by participating to important processes in soil such as soil structure regulation and organic matter dynamics. Earthworms also modify the microbial communities through digestion, stimulation and dispersion in casts. Consequently, changes in the activities of earthworm communities, as a result of soil management practices, can also be used as indicators of soil fertility and quality. It is therefore important to understand how earthworm communities affect soil dynamics. This review adresses the current state of knowledge on earthworm’s impacts on soil structure and soil organic matter (carbon, nitrogen, and phosphorus) dynamics, with special emphasis on the effects of land management practices on earthworm communities. [less ▲]

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See detailImpacts of elevated CO2 on net nitrification and on the community structure of ammonia oxidising bacteria
Malchair, Sandrine ULg; Carnol, Monique ULg

in Biodiversity: state, stakes and future; 7,8 & 9 April 2004, Louvain-la-Neuve, Belgium, Symposium, Programme, Abstracts, Participants (2004)

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See detailImpacts of future floods and low flows on the economy in the Meuse basin
Sinaba, B; Döring, R; Kufeld, M et al

in Dewals, Benjamin; Fournier, Maïté (Eds.) Transboundary Water Management in a Changing Climate (2013)

Climate change in Western Europe is projected to result in more humid winters and drier summers. Further, the sverities of floods and low flows are assumed to increase in the future. The impacts of these ... [more ▼]

Climate change in Western Europe is projected to result in more humid winters and drier summers. Further, the sverities of floods and low flows are assumed to increase in the future. The impacts of these events could lead to adverse consequences on the economy. Given this framework, within the AMICE project, the impacts of future floods and low flow will be analyzed. A flood risk analysis in the Meuse basin is conducted taking into account future climate scenarios. Further, the impacts of future droughts and low flows are analyzed for the economic sectors energy production, agriculture and navigation. [less ▲]

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See detailImpacts of grinding media alloys composition on the flotation of mixed oxides-sulphides copper ores.
Jacques, Simon; Bastin, David ULg

Conference (2011)

While the influence of the grinding media alloy composition on the flotation performances of sulphide ores has been widely studied, its role in the flotation of mixed (oxide and sulphide) ores is poorly ... [more ▼]

While the influence of the grinding media alloy composition on the flotation performances of sulphide ores has been widely studied, its role in the flotation of mixed (oxide and sulphide) ores is poorly documented. For some deposits, the mixed ores zone is well developed and can be of great importance for the economics of a mining project. These ore types often present technical challenges for their beneficiation such as sulphides tarnishment, slimes generation, presence of hydrophobic gangue or presence of acid consuming gangue. This study highlights the importance of matching the right grinding media alloy to the mineralogy of the ore, particularly its degree of weathering and to the subsequent flotation scheme. Shifting the grinding media towards less electrochemically active alloys significantly enhanced the grade-recovery curves and the flotation kinetics of the sulphides fraction, particularly when high degrees of sulphides oxidation were induced within the orebody or during stockpiling. For ores with high acid consuming gangue and medium acid soluble copper content that require a preconcentration of the oxide fraction by flotation through activation by sulphidisation, the higher sulphides flotation rates achieved with the use of high chromium alloys limited the amount of sulphides entering the sulphidisation stages and led to a better selectivity between acid insoluble and acid soluble copper allowing better downstream extractive metallurgy performances. [less ▲]

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See detailImpacts of growth development and age at first calving on first lactation yield in Holstein dairy cows
Picron, Pascale ULg; Froidmont, Eric; Turlot, Amélie et al

Poster (2010, August)

In a context of economic constraints, reducing the herd replacement costs represents a way to improve the economic efficiency of the dairy sector. Studies reported that heifers calving between 23 and 24.5 ... [more ▼]

In a context of economic constraints, reducing the herd replacement costs represents a way to improve the economic efficiency of the dairy sector. Studies reported that heifers calving between 23 and 24.5 mo of age achieved the highest economic return. However, the heifer has to be well developed to guarantee milk performance, calving ease and low stillbirth rate. Monitoring growth, by Heart Girth (HG) measurements, constitute a convenient way to evaluate the feasibility to inseminate heifers early. The aim of this study was to analyse the relationship between HG, age at first calving and milk production at first lactation. HG measurements of 704 Walloon (Belgium) Prim Holstein heifers have been recorded, every 3 months, during 2 years (2006 – 2008). The impact of development, at key-ages (from 3 to 24 mo, every 3 mo), on age at first calving and first lactation yield, was determined using analysis of variance. Mean total milk production in February 2010 (n = 319) rose to 7686 ± 1388 l/365 days of lactation, for a mean age at first calving (n = 421) of 27.4 ± 3.5 mo. These preliminary results suggest a positive correlation between growth performances and first calving age. Heifers with a better conformation (HG > 2.5 % of the French reference) calved significantly earlier than smaller animals. For instance, a lack of conformation at 15 mo implied a delay at first calving of 4.1 mo of age. HG measurement should therefore constitute a preferential tool of management of heifers herd. First lactation yield was significantly higher (950 l/365 d) for heifers calving older (> 30 mo) comparatively to early calving animals (24 mo). These results do not correspond to those related to larger samples in Wallonia. No significant relation could state, at this time, a direct relation between growth development and first lactation yield. Lactation data are still collected to complete this study. [less ▲]

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See detailImpacts of ice sheet mask and resolution on estimating the surface mass balance of the Greenland ice sheet
Fettweis, Xavier ULg

Poster (2008, April 15)

The impacts of the spatial resolution and a Greenland ice sheet (GrIS) mask on modelling the Surface Mass Balance (SMB) are studied with the regional climate model MAR coupled with a complex energy ... [more ▼]

The impacts of the spatial resolution and a Greenland ice sheet (GrIS) mask on modelling the Surface Mass Balance (SMB) are studied with the regional climate model MAR coupled with a complex energy balance/snowpack model. On the one hand, too coarse resolution prevents the model from resolving adequately the steep ice sheet margin and the ablation zone, not wider than 100 km in Greenland, where substantial seasonal melting occurs. The resolution affects also the precipitation modelling. On the other hand, a too large ice sheet mask (i.e. with low-altitude ice pixels in the model, where there is no ice in reality) leads to an overestimation of the run-off. In addition, due to the albedo feedback, biases in the ice sheet mask have also consequences on the surface energy balance. [less ▲]

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See detailImpacts of invasive plants on soil properties, nutrient fluxes and primary productivity
Vanderhoeven, Sonia ULg; Chapuis-Lardy, L.; Dassonville, N. et al

Conference (2006)

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See detailImpacts of land surface properties and atmospheric CO2 on the Last Glacial Maximum climate: a factor separation analysis
Henrot, Alexandra ULg; François, Louis ULg; Brewer, S. et al

in Climate of the Past (2009), 5(2), 183-202

Many sensitivity studies have been carried out, using climate models of different degrees of complexity to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding ... [more ▼]

Many sensitivity studies have been carried out, using climate models of different degrees of complexity to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding the forcings successively as in most previous studies, we applied the separation method of U. Stein et P. Alpert 1993, in order to determine rigorously the different contributions of the boundary condition modifications, and isolate the pure contributions from the interactions among the forcings. We carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the ice sheet expansion and elevation, the lowering of the atmospheric CO2 and of the vegetation cover change on the LGM climate. The separation of the ice cover and orographic contributions shows that the ice albedo effect is the main contributor to the cooling of the Northern Hemisphere, whereas orography has only a local cooling impact over the ice sheets. The expansion of ice cover in the Northern Hemisphere causes a disruption of the tropical precipitation, and a southward shift of the ITCZ. The orographic forcing mainly contributes to the disruption of the atmospheric circulation in the Northern Hemisphere, leading to a redistribution of the precipitation, but weakly impacts the tropics. The isolated vegetation contribution also induces strong cooling over the continents of the Northern Hemisphere that further affects the tropical precipitation and reinforce the southward shift of the ITCZ, when combined with the ice forcing. The combinations of the forcings generate many non-linear interactions that reinforce or weaken the pure contributions, depending on the climatic mechanism involved, but they are generally weaker than the pure contributions. Finally, the comparison between the LGM simulated climate and climatic reconstructions over Eurasia suggests that our results reproduce well the south-west to north-east temperature gradients over Eurasia. [less ▲]

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See detailImpacts of logging and hunting on western lowland gorilla (Gorilla gorilla gorilla) populations and consequences for forest regeneration. A review
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(2), 364-372

Timber exploitation is rapidly expanding throughout the Congo Basin. Forest areas assigned to timber harvesting have sharply expanded over the decades and logging concessions now largely overlap with the ... [more ▼]

Timber exploitation is rapidly expanding throughout the Congo Basin. Forest areas assigned to timber harvesting have sharply expanded over the decades and logging concessions now largely overlap with the range of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847). However this species, which is considered as critically endangered by IUCN, could play an essential role in maintaining the structure and composition of tropical rainforest notably through seed dispersal services. This is likely due to its frugivorous diet, high stomach capacity and ability to swallow seeds of variable sizes. Moreover gorillas have a long gut retention time of ingested food, travel long daily distances and deposit most ingested seeds in suitable habitats for plant development (such as logging gaps). Consequently, the preservation of the role of gorilla in forest regeneration is essential in the context of logged forest ecosystems. Timber harvesting has two major opposing impacts on gorilla populations: on the one hand, gorillas benefit from growth of herbaceous vegetation (e.g. Marantaceae and Zingiberaceae) following forest canopy opening, as such herbs provide both staple food and nest-building materials; on the other hand, gorilla populations suffer with the rise in hunting associated with logging activity, especially with road network installation. Considering the potential negative knock-on effects of logging concessions on the ecological function of western lowland gorilla, the implementation of timber harvesting methods that preserve gorilla populations is a considerable challenge for forest sustainability, as well as for gorilla’s conservation. [less ▲]

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See detailImpacts of management strategies on nutrient fluxes in a temperate Picea abies (L. Karst) plantation
Carnol, Monique ULg

in Jansen, Jörg; Spiecker, Heinrich; von Teuffel, Konstantin (Eds.) Berichte Freiburger Forstliche Forschung, Heft 47, The question of conversion of coniferous forests, Abstracts, International Conference, 27 Septembre - 02 october, 2003, Freiburg im Breisgau, Germany (2003)

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See detailImpacts of occupant behaviours on residential heating consumption for detached houses in a temperate climate of the northern part of Europe
de Meester, Tatiana; Marique, Anne-Françoise ULg; De Herde, André et al

in Energy & Buildings (2013), 57

The occupants' behaviour has a great influence on the energy demand, management and consumption of a building. This paper investigates the influence of three parameters related to human behaviour through ... [more ▼]

The occupants' behaviour has a great influence on the energy demand, management and consumption of a building. This paper investigates the influence of three parameters related to human behaviour through their modes of occupations (based on family size, management of the heating system and management of the heated area) on the housing heating loads of a standard dwelling in Belgium. Seven levels of insulation were tested: no insulation, two intermediate levels corresponding to 3 and 6 cm of insulation, the current standard for new buildings in Belgium, the low energy standard, the very low energy standard and the passive house standard. Multi-zone simulations were performed with a dynamic thermal simulation software. The impact of occupants' lifestyle and the interactions between occupation modes and insulation levels are highlighted. These results prove that the more the building is insulated, the more the lifestyle proportionally influences the heating loads. One important strategy for reducing heating consumption during the whole life cycle of the building is adapting the size of the house and its occupation modes to the evolution of family size. However, insulation is paramount, and increasing the insulation of the house provides generally better results than merely adapting the occupation mode. [less ▲]

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See detailImpacts of occupant behaviours on residential heating consumption for detached houses in a temperate climate of the northern part of Europe
de Meester, Tatiana; Marique, Anne-Françoise ULg; De Herde, André et al

in Energy & Buildings (2013), 57

The occupants' behaviour has a great influence on the energy demand, management and consumption of a building. This paper investigates the influence of three parameters related to human behaviour through ... [more ▼]

The occupants' behaviour has a great influence on the energy demand, management and consumption of a building. This paper investigates the influence of three parameters related to human behaviour through their modes of occupations (based on family size, management of the heating system and management of the heated area) on the housing heating loads of a standard dwelling in Belgium. Seven levels of insulation were tested: no insulation, two intermediate levels corresponding to 3 and 6 cm of insulation, the current standard for new buildings in Belgium, the low energy standard, the very low energy standard and the passive house standard. Multi-zone simulations were performed with a dynamic thermal simulation software. The impact of occupants' lifestyle and the interactions between occupation modes and insulation levels are highlighted. These results prove that the more the building is insulated, the more the lifestyle proportionally influences the heating loads. One important strategy for reducing heating consumption during the whole life cycle of the building is adapting the size of the house and its occupation modes to the evolution of family size. However, insulation is paramount, and increasing the insulation of the house provides generally better results than merely adapting the occupation mode. [less ▲]

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See detailImpacts of past Human disturbances on present day tree species assembly in the tropical forests of South-East Cameroon
Vleminckx, Jason; Doucet, Jean-Louis ULg; Daïnou, Kasso ULg et al

Poster (2013, June 25)

Non-random spatial distribution of trees is the result of both neutral and deterministic factors. Neutral models suggest that species within a community are equally competitive, with spatial structures ... [more ▼]

Non-random spatial distribution of trees is the result of both neutral and deterministic factors. Neutral models suggest that species within a community are equally competitive, with spatial structures mainly due to dispersal limitation. Deterministic (or non-neutral) models consider species assemblages as the result of what we name “induced spatial dependence”, where forcing (explanatory) variables shape diversity organization. However, deterministic models have often included habitat variables only, without considering human disturbance which we know enhances the competitive advantage of heliophytic (light-demanding) species and therefore the floristic composition of phytocenoses. Based on charcoal abundance in the soil (used as an indicator of anthropogenic perturbation), species abundance, and environmental data from a forest of south-east Cameroon, we applied modern variation partitioning methods to assess the relative impact of human disturbance on floristic patterns, controlling for purely spatial and habitat effects. Significant signals of human influence have been found so far, and a new collection of data should establish with a better precision the importance of the anthropogenic impact on tree species assemblages. [less ▲]

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See detailImpacts of past Human disturbances on present-day tree species assembly in a tropical forest of South-East Cameroon
Vleminckx, Jason; Doucet, Jean-Louis ULg; Daïnou, Kasso ULg et al

Poster (2013, November 06)

Many evidence have been found for intensive past Human presence in the forests of Central Africa, notably widespread charcoal occurrence in the soil. Forest clearing for slash-and-burn agriculture may ... [more ▼]

Many evidence have been found for intensive past Human presence in the forests of Central Africa, notably widespread charcoal occurrence in the soil. Forest clearing for slash-and-burn agriculture may have favored the competitiveness of light-demanding species (LD) to the detriment of shade-bearer species (SB). Hypothesis: Positive correlation between abundance of charcoal in the soil (proxy for past Human clearing) and abundance of LD.Mostly “young” charcoals were thought to reflect past Human disturbances that would have shaped present-day species assembly. However, CAI 0-20cm and CAI 20-100cm were highly correlated with each other (r-Pearson = 0.55; P<0.001) and both displayed positive correlations with Non-Pioneer LD abundance (significant with a classic test) and negative correlations with SB abundance. Although this observation is coherent with our hypothesis, significance disappeared when correcting for spatial autocorrelation [4], even after removing small-diameter trees potentially too young to be linked with last Human disturbances (not shown). Correlation of CAI between the two soil layers => Humans found appropriate conditions for settlement in the same area at different periods? Absence of significant correlation in ❸ (i) Last Human disturbances are too old to detect any signal on present-day tree species assembly. (ii) Human impact is weak compared to other factors (soil properties, dispersal limitation,…) (iii) Local scale heterogeneity of LD abundance is weak compared to landscape scale. Parallel large scale gradients in the abundance of Non-Pioneer LD and charcoal abundance (proxy for past slash-and-burn activities) were observed, but a causal link cannot be established so far. [less ▲]

Detailed reference viewed: 56 (17 ULg)