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See detailImpact of simple cheating in application-level multicast
Mathy, Laurent ULiege; Blundell, N.; Roca, V. et al

in INFOCOM 2004. Twenty-third AnnualJoint Conference of the IEEE Computer and Communications Societies (2004)

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See detailImpact of skimming and microfiltration processes on equol concentration in milk
Daems, Frédéric ULiege; Ninane, Véronique; Romnee, Jean-Michel et al

Poster (2016, October 19)

Equol is a microbial metabolite of isoflavones that could be used as therapeutic agent against several diseases and cancers. Cow's milk could be a potential source of equol in the human diet, but more ... [more ▼]

Equol is a microbial metabolite of isoflavones that could be used as therapeutic agent against several diseases and cancers. Cow's milk could be a potential source of equol in the human diet, but more studies are needed on the changes in equol concentration during the technological processing of milk and dairy products. This first exploratory study sought to assess the impact of industrial skimming and microfiltration processes on equol concentration in conventional cow's milk. The milk samples used in this study came from bulk cow’s milk collected in Wallonia (Belgium), by a local dairy and processed in a local cheese factory. Six random sampling were conducted during spring and, for each of them, samples from raw, skimmed and microfiltered milk were analyzed. Equol was present in all samples at a concentration of between 3.2 and 10.3 µg.L-1. A Wilcoxon's signed rank test was then performed on the difference of data, having raw milk as reference, irrespective of the collection date. The results showed that the skimming process slightly increased the equol concentration in milk and therefore that equol had no or little affinity with the lipid milk fraction. The results also showed that, with the microfiltration process, a small proportion of equol was retained. Equol concentration has returned to the same level as that found in raw milk. This might be because of a chemical affinity either with bigger molecules that are physically retained or through direct interaction with the membrane. This scoping study paves the way for more extensive studies on the interaction between equol and other components of the milk. [less ▲]

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See detailImpact of sleep pressure, circadian phase and the ADA polymorphism on cerebral correlates underlying working memory performance
Reichert, Carolin; Maire, Micheline; Gabel, Virginie et al

in Journal of Sleep Research (2014, September), 23(Suppl.1), 10

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See detailIMPACT OF SLUDGE CONDITIONING ON MECHANICAL DEWATERING AND CONVECTIVE DRYING
Bazzaoui, R.; Fraikin, Laurent ULiege; Groslambert, Sylvie ULiege et al

Poster (2011, October)

Management of sludge produced within wastewater treatment plants hasbecome a key issue. After thickening, the removal of remaining water using mechanicaldewatering and/or thermal drying is essential ... [more ▼]

Management of sludge produced within wastewater treatment plants hasbecome a key issue. After thickening, the removal of remaining water using mechanicaldewatering and/or thermal drying is essential before any type of valorization. Polymersare usually employed in the conditioning step in order to promote particle aggregation,making the dewatering easier. In this work the impact of the polymer dosage and natureon dewatering and convective drying of sludge is studied. Results clearly show the impactof conditioning on dewatering performances, however no effect on drying has beenobserved within the range of tested experimental conditions. [less ▲]

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See detailImpact of sludge storage duration on its dewatering and drying ability
Pambou, Yvon-Bert ULiege; Fraikin, Laurent ULiege; Salmon, Thierry ULiege et al

Poster (2013, November 15)

Annual production of sewage sludge in Europe is estimated at more than eleven million tons of dry matter [1]. Use in agriculture and incineration are the main ways of valorization. In this context, drying ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than eleven million tons of dry matter [1]. Use in agriculture and incineration are the main ways of valorization. In this context, drying of residual sludge appears as an essential step after mechanical dewatering. It reduces the costs of storage, transport and allows the sludge stabilization. However, this process is highly energy consuming and still needs to be optimized as it constitutes an important economic and environmental issue [2]. The aim of this paper is to study sludge variability during storage duration, because sludge is a living material that can rapidly change. The study was performed on activated sludge samples collected after thickening from the waste water treatment plant of the Grosses- Battes, closed to University of Liège. The samples were stored in a vessel at fresh room temperature and under stirring. Two types of experiments were conducted, the one (A) during three weeks with one trial a week and the other (B) during five days with one trial a day. The Zetag 7587 conditioner was used for sludge flocculation prior to mechanical dewatering. Optimum dosage was determined by Capillary Suction Time (CST) measurements, it was closed to 18 g/kg DS The dewatering process was made using a normalized filtration-expression cell (AFNOR 1979) under 5 bar of pressure. , the cake dryness obtain was respectively 17 .and 15 %DS for experiment A and B. Before drying, sludge samples were extruded through a cylinder die of diameter and cut at a height of 14 mm, the weight of sample being finally about 2.5 g. The drying experiments were carried out in a specially designed convective dryer, by controlling three operating conditions: the air temperature of 130 °C, the superficial velocity of 1 m/s and the absolute humidity of the air fixed at 0.005 kgwater/ kgDS. The same set up operation was applied for trial [3]. Figure 1 shows the curves of mass loss during the drying, obtained after 1, 8 and 15 days of storage. A poor repeatability of drying curves was observed for activated sludge samples with the increase of storage time on 3 weeks. Whereas figure 2 presents the drying curves for the one week storage, a good repeatability was obtained. No significant effect of sludge variability in a week has shown. It is thus advisable to use a sludge sample during five days and to consider a weekly renewal. [less ▲]

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See detailImpact of sludge storage duration on its dewatering and drying ability
Pambou, Yvon-Bert ULiege

Poster (2013, October)

Annual production of sewage sludge in Europe is estimated at more than twelve million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than twelve million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying appears as an essential step after mechanical dewatering. It reduces the costs of storage and transport, allows the stabilization and the hygienization of sludge while increasing its calorific value. However, sludge is a colloidal system in which particle form a stable suspension in water, making him difficult to be separated from water. The addition of polyelectrolytes chemical is necessary to help the sludge particles to agglomerate into large flocs that can be separate by mechanical dewatering. Before studying experimentally the influence of polymer’s type and dosage on dewatering performances and subsequent drying behaviour, it is necessary to assess the sludge variability during storage duration, because sludge is a highly fermentable material whose properties and composition can rapidly change. [less ▲]

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See detailImpact of sludge storage duration on its dewatering and drying ability Y.B Pambou, T. Salmon, L. Fraikin, M. Crine, and A. Léonard
Pambou, Yvon-Bert ULiege

Poster (2013, October)

Annual production of sewage sludge in Europe is estimated at more than twelve million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than twelve million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying appears as an essential step after mechanical dewatering. It reduces the costs of storage and transport, allows the stabilization and the hygienization of sludge while increasing its calorific value. However, sludge is a colloidal system in which particle form a stable suspension in water, making him difficult to be separated from water. The addition of polyelectrolytes chemical is necessary to help the sludge particles to agglomerate into large flocs that can be separate by mechanical dewatering. Before studying experimentally the influence of polymer’s type and dosage on dewatering performances and subsequent drying behaviour, it is necessary to assess the sludge variability during storage duration, because sludge is a highly fermentable material whose properties and composition can rapidly change. [less ▲]

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See detailImpact of sludge storage on dewatering and convective drying
Pambou, Yvon-Bert ULiege; Salmon, Thierry ULiege; Fraikin, Laurent ULiege et al

Scientific conference (2012, November 10)

Annual production of sewage sludge in Europe is estimated at more than ten million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than ten million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying appears as an essential step after mechanical dewatering. It reduces the costs of storage and transport, allows the stabilization and the hygienization of sludge while increasing its calorific value. However, this process is highly energy consuming and still needs to be optimized as it constitutes an important economic and environmental issue. This implies the improvement of knowledge about sludge drying, including the impact of the mechanical dewatering step. Before studying experimentally the influence of polymers type and dosage use for dewatering on the rheological properties and the drying process, it is necessary to assess the stability of the sludge during of the storage. Because sludge is a living material that can rapidly change, we use the method of experimental design in order to get maximum information with minimal testing, regarding sludge stability during storage. [less ▲]

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See detailThe impact of small physical obstacles on upstream movements of six species of fish - Synthesis of a 5-year telemetry study in the River Meuse basin
Ovidio, Michaël ULiege; Philippart, Jean-Claude ULiege

in Hydrobiologia (2002), 483(1-3), 55-69

In the course of the 'Meuse Salmon 2000' programme, most weirs and dams (3-8 m in height) in the regulated River Meuse have been progressively equipped with new fishways in order to restore the free ... [more ▼]

In the course of the 'Meuse Salmon 2000' programme, most weirs and dams (3-8 m in height) in the regulated River Meuse have been progressively equipped with new fishways in order to restore the free circulation of all amphibiotic fish species. Nevertheless, fish entering into major spawning tributaries are still confronted with various kinds of physical obstacles of which the overall impact on fish migration has never been investigated. In order to test their ability to negotiate physical obstacles, 128 individuals of fish ( Salmo trutta, Thymallus thymallus, Salmo salar, Chondrostoma nasus, Barbus barbus and Esox lucius) were captured several weeks before their spawning migrations and tagged with radio-transmitters. They were tracked from 30 to 466 days in the River Ourthe and six spawning tributaries over the period October 1995 to June 2001. All obstacles recorded in this study have been classified according to their type and main characteristics (i.e. slope, length and height). Results indicated that most fish migrate during or outside the spawning period and that some small obstacles are not as insignificant as initially thought and can significantly disrupt and/or obstruct their upstream movements. There is a need to harmonize interests in the sustainable conservation of fish populations and the development of small-scale hydropower generation and tourism. [less ▲]

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See detailImpact of social protection programs on economic resilience of poor households in Eastern Province of Rwanda
Militery Ngamata, Olivier ULiege; Mbonyinkebe, Deo; Lebailly, Philippe ULiege

in Kovacevic, Dusan (Ed.) Fourth International Scientific Symposium "Agrosym 2013“ : proceedings (2013)

This paper analyses the contribution of three programs of poverty reduction in Rwanda. It uses data from different reports and surveys with beneficiary poor households of social protection programs. The ... [more ▼]

This paper analyses the contribution of three programs of poverty reduction in Rwanda. It uses data from different reports and surveys with beneficiary poor households of social protection programs. The activities developed by these programs have allowed the poor in general and the widows of genocide in the Eastern Province of Rwanda in particular to improve their socioeconomic conditions, notably access to education, accommodation and medical care. Moreover, the beneficiaries have developed activities that diversify households’ revenues and improve their economic resilience. [less ▲]

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See detailImpact of soil and water conservation measures on catchment hydrological response-a case in north Ethiopia
Nyssen, J.; Clymans, W.; Descheemaeker, K. et al

in Hydrological Processes (2010), 24(13), 1880-1895

Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200-ha catchment in north Ethiopia are ... [more ▼]

Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200-ha catchment in north Ethiopia are investigated. The management included various soil and water conservation measures such as the construction of dry masonry stone bunds and check dams, the abandonment of post-harvest grazing, and the establishment of woody vegetation. Measurements at the catchment outlet indicated a runoff depth of 5 mm or a runoff coefficient (RC) of 1·6% in the rainy season of 2006. Combined with runoff measurements at plot scale, this allowed calculating the runoff curve number (CN) for various land uses and land management techniques. The pre-implementation runoff depth was then predicted using the CN values and a ponding adjustment factor, representing the abstraction of runoff induced by the 242 check dams in gullies. Using the 2006 rainfall depths, the runoff depth for the 2000 land management situation was predicted to be 26·5mm(RCD 8%), in line with current RCs of nearby catchments. Monitoring of the ground water level indicated a rise after catchment management. The yearly rise in water table after the onset of the rains (ΔT) relative to the water surplus (WS) over the same period increased between 2002-2003 (ΔT/WS D 3·4) and 2006 (ΔT/WS >11·1). Emerging wells and irrigation are other indicators for improved water supply in the managed catchment. Cropped fields in the gullies indicate that farmers are less frightened for the destructive effects of flash floods. Due to increased soil water content, the crop growing period is prolonged. It can be concluded that this catchment management has resulted in a higher infiltration rate and a reduction of direct runoff volume by 81% which has had a positive influence on the catchment water balance. © 2010 John Wiley & Sons, Ltd. [less ▲]

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See detailImpact of soil management on earthworm diversity according to differential plowing and plant residue incorporation
Lemtiri, Aboulkacem ULiege; Alabi, Taofic; Zirbes, Lara ULiege 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 detailThe impact of soil texture on the selection of nesting sites by the Malachite Kingfisher (Alcedinidae: Alcedo cristata Pallas 1764)
Kisasa Kafutshi, Robert ULiege; Aloni Komanda, Jules

in Ostrich: Journal of African Ornithology (2011), 82(3), 243-246

The first granulometrical analysis of soil samples from nesting banks of the Malachite Kingfisher Alcedo cristata is reported. In total 56 samples from the Kinshasa area were analysed. Three standardised ... [more ▼]

The first granulometrical analysis of soil samples from nesting banks of the Malachite Kingfisher Alcedo cristata is reported. In total 56 samples from the Kinshasa area were analysed. Three standardised particle size fractions were determined in all groups of samples (percentage of sand, clay and silt). Mean particle percentage of soil samples from banks occupied by Malachite Kingfishers averaged 10.8 ± 6.1 of silt, 11.6 ± 6.5 of clay and 81.4 ± 11.4 of sand. A significant difference was found in the proportion of clay between banks with and without kingfisher nests. The results of the present study hence suggest that, as has been documented in other burrowing bird species, soil texture determines the selection of nesting sites in the Malachite Kingfisher. Our results indicate that even a slight difference in the proportion of clay can substantially affect the suitability of banks for the establishment of nests. In fact, burrowing birds must find suitable soils whose structure allows for a good compromise between stability and hardness to dig out, which poses an energy challenge just before the breeding season. [less ▲]

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See detailImpact of sowing density and nitrogen fertilization on Rumex obtusifolius L. development in organic winter cereal crops
Stilmant, Didier; Bodson, Bernard ULiege; Losseau, Céline

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 237-343

The control of Rumex obtusifolius L. (broad-leafed dock) is very important in organic farming systems. Indeed, concerns about managing this weed without the use of herbicides is one of the major factors ... [more ▼]

The control of Rumex obtusifolius L. (broad-leafed dock) is very important in organic farming systems. Indeed, concerns about managing this weed without the use of herbicides is one of the major factors limiting the uptake of these systems by conventional farmers. Against this backround, we analyzed the impact of two management practices on the development of R. obtusifolius populations in two winter cereal trials: spelt (triticum spelta [L.] thell.) and triticale (xtriticosecale [A.Camus]Wittm.). The management factors were sowing density (SD) and nitrogen fertilization (NF) at the tillering stage. The results showed that and increase in SD and NF led to stronger crop growth and better soil coverage by the end of sping, demonstrated by a significant decrease in photosynthetic active radiation (PAR) at soil level. However, although there was an SD effect, it was too weak in April to restrict an increase in R. obtusifolius populations through the recruitment of new R. obtusifulius plants. An increase in R. obtusifolius population density was also linked to an increase in the NF level, illustrating the nitrophilic character of this weed. Although an increase in SD and NF at the tillering stage led to a higher canopy density, these two practices failed to reduce R. Obtusifolius density in the cereal crops. Nevertheless, cereal yields were shown to be maintained or improved. Our results indicate that, even when combining weed harrowing and some cultural weed control methods, this perennial weed is difficult to control. [less ▲]

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See detailImpact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990–2010, using the regional climate model MAR
Franco, Bruno ULiege; Fettweis, Xavier ULiege; Lang, Charlotte et al

in Cryosphere (The) (2012), 6

With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the ... [more ▼]

With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with diminishing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an intelligent interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model, needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries. [less ▲]

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See detailImpact of spatio-temporal sahde on crop growth and productivity, perspectives for temperate agroforestry
Artru, Sidonie ULiege

Doctoral thesis (2017)

Currently, silvoarable agroforestry is receiving renewed interest in Europe, as a land use system that allows for combining the production of commodities with a range of non-commodity outputs, such as ... [more ▼]

Currently, silvoarable agroforestry is receiving renewed interest in Europe, as a land use system that allows for combining the production of commodities with a range of non-commodity outputs, such as environmental protection. Despite the potential of this practice, it remains rarely implemented in Northwestern Europe. One of the obstacles in the adoption of silvoarable agroforestry systems is the lack of quantitative knowledge on the long term performance of different crops when they are competing for resources with trees. In the face of a wide range of possibilities, it remains difficult to obtain a clear overview of overall system functioning. In this thesis, we simplify this complexity by focusing our research questions on the resource of light, based on the assumption that in Belgian climatic conditions light is likely to be the predominant constraint for understorey crops in a silvoarable agroforestry system. With regard to this resource, we develop our research in order to gain insights into the growth mechanisms and final yield of shaded winter wheat and sugar beet crops. We address these questions using an artificial shade system, which has been developed to reproduce the effect of the heterogeneous spatio-temporal pattern of light observed under late-flushing trees in an agroforestry system, isolated from the competition effects for water and nutrients. The shade structures recreate two shade environments: continuous and periodic. The continuous shade treatment leads to shade throughout the entire day, while the periodic shade treatment induces an intermittent shade period, which varies during the day and according to structure orientation. Winter wheat responded to the late application of both shade treatments with a significant decrease in grain yield, which was partly compensated for by an increase in grain protein content. When shaded, sugar beet compensated through morphological adaptations of the aboveground part of the plant, and by a decrease in the final root dry matter and sugar yield. Overall, for both crops, the magnitude of the final yield repercussion varied with the level and period of shade application. Additionally, an arable plot bordered by a row of poplar trees was selected to evaluate the effect of real trees on the winter wheat. The reduction in the final grain yield follows a gradient, from underneath the trees to the centre of the field. Notwithstanding that interactions other than light competition may have occurred, the maximum yield reduction observed under the trees never reaches the level of decrease which is observed under the continuous shade treatment simulated by the artificial shade arrangement. This experimental approach with winter wheat was complemented by a modelling study, in which we evaluate the ability of the STICS crop model to simulate crops growing under dynamic shade. The results highlight the limits of the STICS model when it is used to simulate crop growth under contrasted shade conditions. Finally, we propose agroecology as a conceptual framework for developing sustainable and profitable agroforestry systems in Europe, and reflect on agricultural practices, food systems, and research methodologies. [less ▲]

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See detailImpact of spatio-temporal shade dynamics on wheat growth and yield, perspectives for temperate agroforestry
Artru, Sidonie ULiege; Garré, Sarah ULiege; Dupraz, Christian et al

in European Journal of Agronomy (2017)

A stumbling block to the adoption of silvoarable agroforestry systems is the lack of quantitative knowledge on the performance of different crops when competing for resources with trees. In North-Western ... [more ▼]

A stumbling block to the adoption of silvoarable agroforestry systems is the lack of quantitative knowledge on the performance of different crops when competing for resources with trees. In North-Western Europe, light is likely to be the principal limiting resource for understorey crops, and most agronomic studies show a systematic reduction of final yield as shade increases. However the intensity of the crop response depends on both the environmental conditions and the shade characteristics. This study addressed the issue by monitoring winter wheat (Triticum aestivum L.) growth, productivity and quality under artificial shade provided by military camouflage shade-netting, and using the Hi-sAFe model to relate the artificial shade conditions to those applying in agroforestry systems. The field experiment was carried out over two consecutive years (2013–14 and 2014–15) on the experimental farm of Gembloux Agro-Bio Tech, Belgium. The shade structures recreated two shade conditions: periodic shade (PS) and continuous shade (CS), with the former using overlapping military camouflage netting to provide discontinuous light through the day, and the latter using conventional shade cloth. The experiment simulated shading from a canopy of late-flushing hybrid walnut leaves above winter wheat. Shading was imposed 16 (2013–14) and 10 (2014–15) days before flowering and retained until harvest. The crop experienced full light conditions until the maximum leaf area index stage (LAImax) had been reached. In both years, LAI followed the same dynamics between the different treatments, but in 2013–2014 an attack of the take-all disease (Gaeumannomyces graminis var. tritici) reduced yields overall and prevented significant treatment effects. In season 2014–15 the decrease in global radiation reaching the crop during a period of 66 days (CS: – 61% and PS: – 43%) significantly affected final yield (CS: – 45% and PS: – 25%), mainly through a reduction of the average grain weight and the number of grain per m2. Grain protein content increased by up to 45% under the CS treatment in 2015. Nevertheless, at the plot scale, protein yield (t/ha) did not compensate for the final grain yield decrease. The Hi-sAFe model was used to simulate an agroforestry plot with two lines of walnut trees running either north-south or east-west. The levels of artificial shade levels applied in this experiment were compared to those predicted beneath trees growing with similar climatic conditions in Belgium. The levels used in the CS treatment are only likely to occur real agroforestry conditions on 10% of the cropped area until the trees are 30 years old and only with east-west tree row orientation. [less ▲]

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See detailThe impact of sperm precedence in malathion resistance transmission in populations of the red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)
Haubruge, Eric ULiege; Arnaud, Ludovic; Mignon, Jacques ULiege

in Journal of Stored Products Research (1997), 33(2), 143-146

Malathion resistance in the red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is actually a worldwide problem, and studies on resistance transmission are needed to improve ... [more ▼]

Malathion resistance in the red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is actually a worldwide problem, and studies on resistance transmission are needed to improve insecticide resistance management. Females of Tribolium castaneum commonly mate with several males, and the last batch of male sperm preferentially fertilizes subsequent eggs. This phenomenon, a particular form of sexual selection, helps to increase resistance transmission in populations of stored product insects. We confirmed the last male sperm precedence and, in the absence of further matings, examined the evolution of mixed susceptible and malathion-resistant progeny during a 3-month period. The proportion of resistant phenotypes in female progeny was 99.6 and 3%, respectively, after the first mating with a resistant male and the second mating with a susceptible one. When females thus mated twice were isolated from males, the proportion of the resistant phenotype increased to 34.1% after 30 days. From 72 days onwards, this proportion ranged from 14.2 to 29.7%. (C) 1997, Published by Elsevier Science Ltd. [less ▲]

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