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See detailDo aphids actively search for ant partners?
Fischer, Christophe ULg; Vanderplanck, Maryse; Lognay, Georges ULg et al

in Insect Science (2015), 22(2), 283-288

The aphid–ant mutualistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is ... [more ▼]

The aphid–ant mutualistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is largely assumed that ants actively search for their mutualistic partners namely using volatile cues; whether winged aphids (i.e. aphids’ most mobile form) are able to select ant-frequented areas had not been investigated so far. Ant-frequented sites would indeed offer several advantages for these aphids including a lower predation pressure through ant presence and enhanced chances of establishing mutuaslistic interactions with neighbour ant colonies. In the field, aphid colonies are often observed in higher densities around ant nests, which is probably linked to a better survival ensured by ants’ services. Nevertheless, this could also result from a preferential establishment of winged aphids in ant-frequented areas. We tested this last hypothesis through different ethological assays and show that the facultative myrmecophilous black bean aphid, Aphis fabae L., does not orientate its search for a host plant preferentially towards ant-frequented plants. However our results suggest that ants reduce the number of winged aphids leaving the newly colonized plant. Thus, ants involved in facultative myrmecophilous interactions with aphids appear to contribute to structure aphid populations in the field by ensuring a better establishment and survival of newly established colonies rather than by inducing a deliberate plant selection by aphid partners based on the proximity of ant colonies. [less ▲]

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See detailDo aphids and their predators use the same OBP to transport a same odour?
Vandermoten, Sophie ULg; Fan, Jia; Liu, Yong et al

Poster (2010, August)

Detailed reference viewed: 37 (1 ULg)
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See detailDo babies resemble their fathers more than their mothers ? : a failure to replicate Christenfeld and Hill
Brédart, Serge ULg; French, R.

in Evolution and Human Behavior : Official Journal of the Human Behavior and Evolution Society (1999), 20(3), 129-135

Contrary to Christenfeld

Detailed reference viewed: 43 (2 ULg)
See detailDo Board Characteristics Affect Information Asymmetry?
Sougné, Danielle ULg; Ajina, Aymen ULg

Scientific conference (2014, May 19)

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See detailDo Board Characteristics Affect Information Asymmetry?
Sougné, Danielle ULg; Laouti, Mhamed; Ajina, Aymen ULg

in International Journal of Academic Research in Business and Social Sciences (2013), 3(12), 660-675

In this paper, we investigate the empirical relationship between corporate governance and information asymmetry across a range of French firms. Based on a cross-sectional analysis, our study of the ... [more ▼]

In this paper, we investigate the empirical relationship between corporate governance and information asymmetry across a range of French firms. Based on a cross-sectional analysis, our study of the empirical relationship between corporate governance and information asymmetry involved 160 companies over the years 2008-2010. Mechanisms of corporate governance include the characteristics of the board of directors. Our results seem to indicate a significant relationship between certain mechanisms of corporate governance and the information asymmetry of the French market. These mechanisms can reduce adverse selection costs, and make exchanges more transparent. These results suggest that firms with efficient corporate governance mechanisms may reduce informative asymmetry and improve transparency between investors. [less ▲]

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See detailDo Bovine Lymphocytes Express a Peculiar Prion Protein?
Mélot, France ULg; Thielen, Caroline ULg; Labiet, T. et al

in Developmental Immunology (2002), 9(4), 245-52

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the ... [more ▼]

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the pathogenesis of various transmissible spongiform encephalopathies (TSEs). In bovine species, BSE infectivity appears to be restricted to the central nervous system; few or no detectable infectivity is found in lymphoid tissues in contrast to scrapie or variant CJD. Since expression of PrPc is a prerequisite for prion replication, we have investigated PrPc expression by bovine immune cells. Lymphocytes from blood and five different lymph organs were isolated from the same animal to assess intra- and interindividual variability of PrPc expression, considering six individuals. As shown by flow cytometry, this expression is absent or weak on granulocytes but is measurable on monocytes, B and T cells from blood and lymph organs. The activation of the bovine cells produces an upregulation of PrPc. The results of our in vitro study of PrPc biosynthesis are consistent with previous studies in other species. Interestingly, western blotting experiments showed only one form of the protein, the diglycosylated band. We propose that the glycosylation state could explain the lack of infectivity of the bovine immune cells. [less ▲]

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See detailDo Burundians have a more positive perception of older people than immigrants or Belgians?
Marquet, Manon ULg; Missotten, Pierre ULg; Nindaba, Desiderate et al

in International Psychogeriatrics (2016), 27(Supplement 1), 70-172

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See detailDo canine scalene and sternomastoid muscles play a role in breathing?
De Troyer, A.; Cappello, M.; Brichant, Jean-François ULg

in Journal of Applied Physiology (Bethesda, Md. : 1985) (1994), 76(1), 242-52

To assess the respiratory function of the scalene and sternomastoid muscles in the dog, we studied the effect of graded increases in inspiratory airflow resistance and single-breath airway occlusion on ... [more ▼]

To assess the respiratory function of the scalene and sternomastoid muscles in the dog, we studied the effect of graded increases in inspiratory airflow resistance and single-breath airway occlusion on the electrical activity of these muscles in 18 supine anesthetized spontaneously breathing animals. The sternomastoids never showed any activity, and the scalenes showed some inspiratory activity during occlusion in only two animals. The adoption of the prone position and bilateral cervical vagotomy did not affect this pattern. Hypercapnia also did not elicit any sternomastoid activity and induced scalene inspiratory activity during occlusion in only four of nine animals. On microscopic examination, however, both muscles were found to contain large numbers of spindles, suggesting that they have the capacity to respond to stretch. In addition, with increases in inspiratory resistance, both the sternum and ribs were displaced in the caudal direction. As a result, the scalenes demonstrated a gradual inspiratory lengthening and the normal inspiratory lengthening of the sternomastoids was accentuated. Additional studies in three unanesthetized animals showed consistent activity in the scalene and sternomastoid muscles during movements of the trunk and neck but no activity during breathing, including occluded breathing. These observations thus indicate that the alpha-motoneurons of the scalene and sternomastoid muscles in the dog have very small central respiratory drive potentials with respect to their critical firing threshold. In this animal, these muscles do not have a significant respiratory function. [less ▲]

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See detailDo changes in atmospheric CO2 concentration affect aphid alarm signaling?
Boullis, Antoine ULg; Appeldoorn, Claire; Oostrom, Marjolein et al

Conference (2015, November 06)

The effects of global atmospheric changes on vegetation and associated insect populations are increasingly studied, but how these gases affect the interactions between herbivore insects and their natural ... [more ▼]

The effects of global atmospheric changes on vegetation and associated insect populations are increasingly studied, but how these gases affect the interactions between herbivore insects and their natural enemies is less clear. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in the behavior of insect prey defenses can change the dynamics of insect populations. The impact of increases in atmospheric carbon dioxide (CO2) concentrations on aphid population dynamic is well documented. However, few publications about their chemical ecology are reported. Aphids are using many chemical signals to communicate with each other or with their environment. For example aphids produce an alarm pheromone to signal the presence of a natural enemy in the colony. For our experiments, aphids Acyrthosiphon pisum (Harris) were reared on Vicia faba L. in home-made Plexiglas® chambers, allowing us to control the CO2 concentration, temperature and humidity. Aphids were reared under both ambient (aCO2 ≈ 400 ppm) and elevated (eCO2 ≈ 800 ppm) CO2 concentration for several generations. Here we quantified the emission of (E)-β-Farnesene (EβF - main compound of alarm pheromone) released by predated aphids reared under ambient or elevated CO2 concentration, with two different methods: a real-time analysis, and the total amount analysis. The EβF content of whole aphid bodies was also analyzed, as well as the escape behavior of aphid colony according to the growing conditions of aphid populations. These results will be discussed in terms of biological control in future climate. [less ▲]

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See detailDo climate warming and plant species richness affect potential nitrification, basal respiration and ammonia-oxidizing bacteria in experimental grasslands?
Malchair, Sandrine ULg; De Boeck, Hans, J.; Lemmens, Catherine, M.H.M. et al

in Soil Biology & Biochemistry (2010), 42

Ammonia-oxidizing bacteria (AOB) are key organisms in the N cycle, as they control the first, rate-limiting step of the nitrification process. The question whether current environmental disturbances, such ... [more ▼]

Ammonia-oxidizing bacteria (AOB) are key organisms in the N cycle, as they control the first, rate-limiting step of the nitrification process. The question whether current environmental disturbances, such as climate warming and plant diversity losses, select for a particular community structure of AOB and/or influence their activity remains open. The purpose of this research was to study the impact of a 3 °C warming and of plant species richness (S) on microbial activity and diversity in synthesized grasslands, with emphasis on the nitrification process and on the diversity (community structure and richness) of ammonia-oxidizing bacteria (AOB).We measured soil chemical characteristics, basal respiration, potential nitrification and AOB diversity in soils under increasing plant species richness (S ¼ 1, S ¼ 3, S ¼ 9) at ambient and (ambient +3 °C) temperature. Species were drawn from a 9-species pool, belonging to three functional groups: forbs, legumes and grasses. Mixtures comprised species from each of the three functional groups. Warming did not affect AOB diversity and increased potential nitrification at S ¼ 3 only. Under warmed conditions, higher plant species richness resulted in increased potential nitrification rates. AOB richness increased with plant species richness. AOB community structure of monocultures under legumes differed from those under forbs and grasses. Clustering analysis revealed that AOB community structure under legume monocultures and mixtures of three and nine species grouped together. These results indicate that functional group identity rather than plant species richness influenced AOB community structure, especially through the presence of legumes. No clear relationship emerged between AOB richness and potential nitrification whatever plant species richness and temperature treatment. Our findings show a link between aboveground and belowground diversity, namely plant species richness, AOB richness and community structure. AOB richness was not related to soil processes, supporting the idea that increased diversity does not necessarily lead to increased rates of ecosystem processes. [less ▲]

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See detailDo clinical factors help to predict disease course in inflammatory bowel disease?
Louis, Edouard ULg; Belaiche, Jacques ULg; Reenaers, Catherine ULg

in World Journal of Gastroenterology (2010), 16(21), 2600-3

While therapeutic strategies able to change the natural history of the disease are developing, it is of major importance to have available predictive factors for aggressive disease to try and target these ... [more ▼]

While therapeutic strategies able to change the natural history of the disease are developing, it is of major importance to have available predictive factors for aggressive disease to try and target these therapeutic strategies. Clinical predictors have probably been the most broadly studied. In both Crohn's disease (CD) and ulcerative colitis (UC), age at diagnosis, disease location and smoking habit are currently the strongest predictors of disease course. A younger age at onset is associated with more aggressive disease both in CD and UC. Disease location in CD is associated with different types of complications: surgery and recurrence in upper gastrointestinal and proximal small bowel disease; and surgery in distal small bowel disease and peri-anal lesions in rectal disease. In UC, extensive colitis is clearly been associated with more severe disease. Finally, active smoking globally increases disease severity in CD but decreases it in UC. Besides these important factors, others may predispose to some specific disease evolution and complications, and are also reviewed in the present paper. [less ▲]

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See detailDo common principles underlie the representation of order in STM and numerical judgment tasks?
Attout, Lucie ULg; Majerus, Steve ULg

Conference (2012, March 29)

Although many studies have explored magnitude effects in numerical cognition, the representation of order information has received only limited interest. We explored the hypothesis that common abstract ... [more ▼]

Although many studies have explored magnitude effects in numerical cognition, the representation of order information has received only limited interest. We explored the hypothesis that common abstract ordinal representations underlie the representation of order information across different domains. We tested this hypothesis by determining the similarity of distance effects in short-term memory (STM) order probe recognition (did ‘8’ occur before ‘5’ in the list ‘3, 6, 5, 4, 8, 7’ presented a few seconds ago?) and in order judgment tasks (does ‘1’ occur before ‘2’), both numerical and alphabetical stimuli were used. In numerical cognition, adjacent numbers are typically judged more slowly than more distant numbers. In fifty healthy adults, we observed significant distance effects across all tasks: in the order judgment tasks, adjacent numbers/letters were judged more slowly than more distant numbers/letters; in the STM tasks, order recognition was slowed for stimuli stemming from adjacent positions in the STM list as compared to stimuli stemming from more distant positions. Regression slopes for distance effects were identical across the different tasks and conditions. Furthermore, the size of distance effects correlated significantly across tasks, except for the order judgment task with numerical stimuli. We will discuss the implications of these results for a hypothetical common representational system of order information in STM and numerical cognition. [less ▲]

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See detailDo Consumers Pay More for What They Value More? The Case of Local Milk-based Dairy Products in Senegal
Lefevre, Mélanie ULg

in Agricultural and Resource Economics Review (2014), 43(1), 158-177

Senegalese consumers prefer milk-based dairy products that are local and fresh to ones produced with imported powder. However, prices for fresh-milk-based and powder-based products are not significantly ... [more ▼]

Senegalese consumers prefer milk-based dairy products that are local and fresh to ones produced with imported powder. However, prices for fresh-milk-based and powder-based products are not significantly different. I address this puzzle by first confirming the preference using choice-based conjoint data to evaluate whether Senegalese consumers will pay a significant positive premium for fresh local products. I then identify price determinants using a unique dataset of milk product characteristics. The results verify the Senegalese preference for fresh local dairy products and show that consumers’ misinformation regarding product composition prevents them from allocating a higher price to local milk-based products. [less ▲]

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See detailDo consumers pay more for what they value more? The case of local milk-based dairy products in Senegal
Lefevre, Mélanie ULg

E-print/Working paper (2013)

Senegalese consumers seem to prefer local fresh milk-based dairy products rather than the ones produced with imported powder. However, market prices of both products do not appear to be different. This ... [more ▼]

Senegalese consumers seem to prefer local fresh milk-based dairy products rather than the ones produced with imported powder. However, market prices of both products do not appear to be different. This paper addresses this puzzle. First, I confirm the preference for local products. Using choice-based-conjoint data, I evaluate that Senegalese consumers are willing to pay a positive and significant premium for these products. Then, I identify the determinants of prices, based on a unique dataset of milk products characteristics. Evidence suggests that consumers' misinformation regarding the product composition prevents them from allocating a higher price to local milk-based products. [less ▲]

Detailed reference viewed: 43 (4 ULg)
See detailDo consumers pay more for what they value more? The case of local milk-based dairy products in Senegal
Lefevre, Mélanie ULg

Scientific conference (2013, June 23)

Senegalese consumers seem to prefer local fresh milk-based dairy products rather than the ones produced with imported powder. However, market prices of both products do not appear to be different. This ... [more ▼]

Senegalese consumers seem to prefer local fresh milk-based dairy products rather than the ones produced with imported powder. However, market prices of both products do not appear to be different. This paper addresses this puzzle. First, I confirm the preference for local products. Using choice-based-conjoint data, I evaluate that Senegalese consumers are willing to pay a positive and significant premium for these products. Then, I identify the determinants of prices, based on a unique dataset of milk products characteristics. Evidence suggests that consumers' misinformation regarding the product composition prevents them from allocating a higher price to local milk-based products. [less ▲]

Detailed reference viewed: 21 (4 ULg)
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See detailDo countries of origin contribute to socio-cultural integration of migrants abroad?
Gsir, Sonia ULg

in Fargues, Philippe; Weinar, Agnieszka; Di Bartolomeo, Anna (Eds.) et al From Home to Home? How countries of origin impact immigrant integration outcomes (in press)

Detailed reference viewed: 16 (0 ULg)