Last 7 days
Bookmark and Share    
Full Text
See detailMécanismes de concentration du carbone (CCMs) chez les algues
Gerin, Stéphanie ULg

Scientific conference (2014, May 06)

Description des mécanismes de concentration du carbone (CCMs) développés par les algues pour augmenter la disponibilité en CO2 dans l'environnement local de la RubisCO. De tels mécanismes permettent de ... [more ▼]

Description des mécanismes de concentration du carbone (CCMs) développés par les algues pour augmenter la disponibilité en CO2 dans l'environnement local de la RubisCO. De tels mécanismes permettent de limiter l'activité oxygénase de l'enzyme et d'atteindre la vitesse de catalyse maximale (Vmax). La présente communication se focalise particulièrement sur les CCMs biophysiques des cyanobactéries et de l'algue verte unicellulaire modèle Chlamydomonas reinhardtii. [less ▲]

Detailed reference viewed: 21 (7 ULg)
Full Text
See detailCaractérisation des modes de consommation alimentaire des ménages à Kinshasa : analyse des interrelations entre modes de vie et habitudes alimentaires
Muteba Kalala, Damien ULg

Doctoral thesis (2014)

This study was initiated at the start of a hypothesis that households are in a situation of food insecurity when their lifestyles and livelihoods have changed or have not adapted and they have not the ... [more ▼]

This study was initiated at the start of a hypothesis that households are in a situation of food insecurity when their lifestyles and livelihoods have changed or have not adapted and they have not the ability to find a balance between a set of needs. Households’ food demand cannot be analyzed independently from all livelihoods and living conditions. For this study, a methodology based on household surveys was adopted. Based on their supposed wealth level, three districts were selected, the Residential Area in Limete, the Mabulu neighbourhood in Makala and Quarters I and VII in Ndjili. A sample of 346 households was selected. The results of the first survey on the characterization of households have achieved the first three objectives of the study. The second survey consisted of a household monitoring defined according to specific criteria. Thirty households were selected at the rate of 10 in each of three quarters. They were followed first during the dry season for three months, from June to August 2011, and subsequently in the rainy season for three months also between February and April 2012. The results of this study show among other things that food expenditures are much higher in the rainy season than in the dry season. However, the quantities consumed are relatively higher in the dry season than in the rainy season. The amount of food consumed per person per day was estimated in the dry season respectively at 1.202g (in the richest households), 833g (in average households) and 506g (in poor households). During the rainy season, quantities consumed are respectively of 1.120g (in the richest neighborhood), 801g (in the average households) and 493g (in less well-off households). Energy intake per person per day in the dry season is respectively 2571 calories (in the richest households), 1.864 calories (in average households) and 1,094 calories (in poor households). Energy intake was also lower in the rainy season. It reaches respectively 2.452 calories (in wealthy households), 1,838 calories (in average households) and 1,130 calories (in poor households). Protein intake per person per day was estimated in the dry season respectively at 102g (wealthier households), 81g (in average households) and 51g (in poor households). During the rainy season, these contributions are also low. They are around of 100g in the wealthier households, 80g in the average households and 50g in poor households. The analysis of different consumption patterns showed that the dietary habits of Kinshasa do not seem to meet the nutritional requirements. Considerations between the two parameters show that households are scarcely managing to find a balance. The evidence supporting this difficult balancing includes: food monotony in households, the tendency to promote the consumption of cheap food, food choices unrelated to dietary considerations, the appearance of more and more public health problems related to food consumption patterns. However, the dietary imbalance in Kinshasa households is not always linked to income. [less ▲]

Detailed reference viewed: 71 (26 ULg)
Full Text
See detailHypoxia in macrophytodetritus accumulation: Species specific harpacticoid copepod adaptation?
Mascart, Thibaud ULg; De Troch, Marleen; Gobert, Sylvie ULg et al

Poster (2014, May 05)

Mediterranean Posidonia oceanica seagrass meadows generate high primary production and support large biodiversity of associated fauna and flora. The majority of the foliar material falls on the ... [more ▼]

Mediterranean Posidonia oceanica seagrass meadows generate high primary production and support large biodiversity of associated fauna and flora. The majority of the foliar material falls on the unvegetated sea floor during the autumnal leaf senescence, fuelling the detrital food web. Whilst laying on the sea floor the freshly formed macrophytodetritus pile up into accumulations according to the local hydrodynamics and seafloor geomorphology. In these litter accumulations, harpacticoid copepods (Crustacea, Copepoda) are the main meiofaunal players (metazoans in the size range of 38µm – 1mm) and show a high specific diversity. They are primarily grazers, but their high specific diversity suggests that they occupy also a large variety of trophic niches. This large morphological and trophic diversity can partly be promoted by the complexity of the phytodetritus in seagrass accumulations. On the other hand, macrophytodetritus degradation and flux of reduced compounds from the sediments is responsible for oxygen consumption inside the accumulation of seagrass litter. Therefore, concentration of oxygen inside the accumulation is very variable and often under the concentration observed in the water column just above the litter. Frequently, oxygen levels reach very low values. The present study aims to link the oxygen variability inside the accumulation to the densities of the five most dominant harpacticoid copepods found living in the P. oceanica litter. Standardized samples were collected seasonally in two contrasting sites of the Calvi Bay (Corsica) during one year. Our results showed no correlation between the oxygen concentrations and harpacticoid community diversity or their total abundances. The five most dominant species showed divergent results, but none had a clear correlation with the oxygen concentration. This contrasts with observation done for sediment meiofaunal community where most harpacticoid copepods are sensitive to oxygen level and where nematodes often dominate the community. This could be explained by their high mobility and the patchiness and variability of the oxygen concentrations present in the accumulations. Harpacticoid copepods, whilst being sensitive to hypoxia and anoxia developed a strategy to live in this fast oxygen changing environment. To conclude, our results underline the importance of species-specific analysis of correlation data. Especially in complex and dynamic environments where a variety of potential trophic niches are present and species competition is very likely to occur. The overall abundance pattern and diversity of the copepod community showed no relation to the oxygen concentration while the most abundant copepod species did not responded to fluctuating oxygen concentrations. [less ▲]

Detailed reference viewed: 22 (0 ULg)
Full Text
See detailCorrelation between the acoustic noise field measured in a Posidonia oceanica bed and the photosynthetic activity
Felisberto, P; Zabel, F; Rodriguez, O et al

Poster (2014, May 05)

Detailed reference viewed: 12 (2 ULg)
Full Text
See detailRates of microbial sulfur oxidation in low oxygen environments
Crowe, SA; Canfield, DE; Sturm, A et al

Poster (2014, May 05)

Detailed reference viewed: 60 (0 ULg)
Full Text
See detailAmmonia Oxidising Archaea in the OMZ of a freshwater African Lake
Lliros, M; Ingeoglu, O; Garcia-Armisen, T et al

Poster (2014, May 05)

Detailed reference viewed: 25 (0 ULg)
Full Text
See detailAnaerobic methane oxidation in two tropical freshwater systems
Roland, Fleur ULg; Darchambeau, François ULg; Crowe, SA et al

Poster (2014, May 05)

Detailed reference viewed: 11 (2 ULg)
Full Text
Peer Reviewed
See detailHexis
Durand, Pascal ULg

E-print/Working paper (2014)

Définition et discussion du concept d'« Hexis » dans la sociologie de Pierre Bourdieu.

Detailed reference viewed: 46 (14 ULg)
Full Text
Peer Reviewed
See detailCapital symbolique
Durand, Pascal ULg

E-print/Working paper (2014)

Présentation et discussion du concept de « Capital symbolique » dans la sociologie de Pierre Bourdieu.

Detailed reference viewed: 70 (15 ULg)
Full Text
Peer Reviewed
See detailIllusio
Durand, Pascal ULg

E-print/Working paper (2014)

Définition et discussion du concept d'« Illusio » dans la sociologie de Pierre Bourdieu.

Detailed reference viewed: 39 (17 ULg)
Full Text
See detailNo performance reduction at the present northern edge of Ambrosia artemisiifolia L. invasion range
Ortmans, William ULg

Conference (2014, May 05)

Plant populations at range edges may exhibit reduction of performances and fitness. In the case of biological invasions, such a reduction could be associated with a slowing down of the spread and explain ... [more ▼]

Plant populations at range edges may exhibit reduction of performances and fitness. In the case of biological invasions, such a reduction could be associated with a slowing down of the spread and explain the non-naturalization of a species outside its present invasion range. Common ragweed (Ambrosia artemisiifolia L.) is an ideal model to investigate such processes, since it is invasive in France but not naturalized in northern countries, such as Belgium and the Netherlands. In this study, we test if the performances of ragweed populations vary among different invasion zones. Three populations were selected in each of four invasion zones in Western Europe: 1) French invasion area; 2) northern and 3) southern invasion edges; and 4) outside the invasion area (Belgium and Netherlands). Field performances (growth, reproduction, stress resistance) were recorded on 25 plants per population. Furthermore, the competition by the native flora was assessed around each plant. Generalized Linear Models were used to compare performance among invasion zones and populations, with competition as covariate. Regressions were also performed to assess the influence of climatic data on population performances. No evidence of decreasing performances was found at the edges of the invasion area, neither outside of it, suggesting that the invasion front has the potential to keep going northwards. Competition by native flora had a significant impact on stress resistance, but did not decrease reproduction or growth. These results are discussed in the light of other ongoing experiments in Belgium. [less ▲]

Detailed reference viewed: 25 (8 ULg)