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See detailControl of attosecond electronic dynamics in molecules
Mignolet, Benoît ULg

Doctoral thesis (2014)

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See detailCharcoal records reveal past occurrences of perturbations in the forests of the Kisangani region(RDC): vegetation history of the semi-deciduous rainforest
Tshibamba Mukendi, John; Hubau, Wannes; Morin-Rivat, Julie ULg et al

Poster (2014, April 28)

Introduction. Past disturbances have modified the structure and the floristic composition of Central African rainforests. These perturbations represent a driving force for forest dynamics and they are ... [more ▼]

Introduction. Past disturbances have modified the structure and the floristic composition of Central African rainforests. These perturbations represent a driving force for forest dynamics and they are presumably at the origin of present-day forest mosaics. Fire is a prominent forest disturbance, leaving behind charcoal as a witness of past forest dynamics. The question arises whether quantification, dating and botanical identification of ancient charcoal fragments found in soil layers (pedoanthracology) allows a detailed reconstruction of forest history, including the possible occurrence of past disturbances. Material & methods. We organized pedoanthracological excavations in 6 regrowth sites and 48 sites of primary forests of Yangambi, Yoko, Masako and Kole in the Kisangani (RDC). We performed a detailed sampling in different vegetation types of a semi -deciduous rainforest (Yoko). Charcoal sampling was conducted in pit intervals of 10 cm. The charcoal was quantified whereby pottery fragments were also registered. A selection of charcoal fragments has been dated through AMS 14C measurement. Floristic identifications were conducted using. former protocols based on wood anatomy, which is largely preserved after charcoalification. Results. Charcoal was found in most pit intervals. The anthracomass in the soil of regrowth forests (secondary forests) is much higher than in the primary forest: 27,59 mg/kg for secondary forests et 2,53 mg/kg for primary forests. The specific soil anthracomass of the primary forest of the Yoko reserve is higher (7,7 mg/kg) than in Yangambi (1,9 mg/kg) , Masako (1,7 mg/kg) and Kole (0,8 mg/kg). No systematic differences have been found between soil charcoal content of the different forest type representing different forest histories. Gilbertiodendron dewevrei (De Wild.) J. Leonard forests showed surprisingly a higher concentration of soil charcoal. Discussion. Forest disturbances in the Kisangani region appear to be more recent than those in the Mayombe forest in Western RDC ( 3000-2000 calBP (Hubau, 2013)) and those of the Cameroon forest (2300-1300 calBP) (Morin-Rivat, J et al., 2014). Stratified charcoal conserved in the soil is a useful indicator of past forest disturbances. [less ▲]

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See detailDioxin Analyses. The Dogs Bark, but the Caravan Goes on...
Focant, Jean-François ULg

Scientific conference (2014, April 28)

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See detailApplication of multi-scale variography for inferring the spatial variability of the hydraulic conductivity of a sandy aquifer
Rogiers, Bart; Vienken, Thomas; Gedeon, M et al

Poster (2014, April 28)

In the framework of the disposal of short-lived low- and intermediate-level radioactive waste in a near-surface disposal facility in Dessel (Belgium), extensive characterization of the hydraulic ... [more ▼]

In the framework of the disposal of short-lived low- and intermediate-level radioactive waste in a near-surface disposal facility in Dessel (Belgium), extensive characterization of the hydraulic conductivity (K) in the shallow Neogene aquifer has been performed at a regional scale. In the last few years the small-scale heterogeneity has been additionally characterized by outcrop analogue, hydraulic direct push, and borehole core air permeameter studies. The gathered data now include a) more than 350 hydraulic conductivity measurements on samples from 8 cored boreholes, mostly reaching depths of 50 m and data at 2 m intervals, b) more than 5000 air permeability measurements on the same borehole cores, c) more than 250 cone penetration tests (CPTs) with depths down to 40 m and data at 2 cm intervals, d) over 100 dissipation tests performed during the CPT campaigns, e) 17 direct push injections loggings, 6 hydraulic profiling tool logs, and 6 direct push slug tests, f) several hundreds of air permeability measurements on outcrop analogues of the aquifer sediments, and g) numerous grain size analyses. The current study aims to quantify the heterogeneity of K from the centimetre- to the kilometre-scale and to check the compatibility of the spatial variability revealed by the different datasets. This is achieved through gathering all K values (either direct measurements, calibrated relative K values, or K estimates from secondary data), and the use of variography to quantify spatial variability in terms of two-points geostatistics. The results are discussed, and the main differences between the different data sources are explained. In a final step, different multi-scale variogram models are proposed for capturing the main characteristics of multi-scale variability within the shallow Neogene aquifer in Belgium. [less ▲]

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See detailThe age of river-transported carbon: new data from African catchments and a global perspective
Marwick, TR; Tamooh, F; Teodoru, C et al

Conference (2014, April 27)

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See detailDisproportionate contribution of riparian inputs to organic carbon in freshwater systems
Marwick, TR; Van Acker, K; Darchambeau, François ULg et al

Conference (2014, April 27)

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See detailInorganic and organic carbon spatial variability in the Congo River during high waters (December 2013)
Borges, Alberto ULg; Bouillon, S; Teodoru, C et al

Poster (2014, April 27)

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See detailEutrophication counteracts ocean acidification effects on DMS emissions
Gypens, N; Borges, Alberto ULg

Poster (2014, April 27)

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See detailTemporal variability and spatial dynamics of CO2 and CH4 concentrations and fluxes in the Zambezi River system
Teodoru, C; Borges, Alberto ULg; bouillon, S et al

Conference (2014, April 27)

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See detailDrivers on carbon dioxide emissions from the Scheldt river basin
Gypens, N; Passy, P; Garnier, J et al

Poster (2014, April 27)

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See detailAnaerobic methane oxidation in two tropical freshwater systems
Roland, Fleur ULg; Darchambeau, François ULg; Crowe, SA et al

Poster (2014, April 27)

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