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See detailLate Night, la danse de la déperdition
Delhalle, Nancy ULg

in Alternatives Théâtrales (2014), (120),

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See detailLate Ordovician-earliest Silurian palynomorphs from northern Chad and correlation with contemporaneous deposits of southeastern Libya
Le Hérissé, A.; Paris, F.; Steemans, Philippe ULg

in Bulletin of Geosciences (2013), 83(3), 483-504

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See detailLate Pleistocene molecular dating of past population fragmentation and demographic changes in African rain forest tree species supports the forest refuge hypothesis
Duminil, Jérôme; Mona, Stefano; Mardulyn, Patrick et al

in Journal of Biogeography (2015), 42

Aim : Phylogeographical signatures of past population fragmentation and demographic change have been reported in several African rain forest trees. These signatures have usually been interpreted in the ... [more ▼]

Aim : Phylogeographical signatures of past population fragmentation and demographic change have been reported in several African rain forest trees. These signatures have usually been interpreted in the light of the Pleistocene forest refuge hypothesis, although dating these events has remained impracticable because of inadequate genetic markers. We assess the timing of interspecific and intraspecific genetic differentiation and demographic changes within two rain forest Erythrophleum tree species (Fabaceae: Caesalpinioideae). Location : Tropical forests of Upper Guinea (West Africa) and Lower Guinea (Atlantic Central Africa). Methods : Six single-copy nuclear genes were used to characterize the phylogeographical patterns of the parapatric sister species Erythrophleum suaveolens (characteristic of semi-deciduous or gallery forests) and Erythrophleum ivorense (characteristic of evergreen forests). The number of gene pools within each species was determined and the timings of their divergence and past demographic changes were estimated using Bayesian-based coalescent approaches. Results : Three geographically separated gene pools were identified within E. suaveolens, and a single gene pool was inferred in E. ivorense. All gene pools show signatures of demographic bottlenecks concomitant with the last glacial period (c. 120–12 ka). Species-tree inferences show that the two species diverged c. 600 ka, whereas the divergence between E. suaveolens gene pools was dated to the late Pleistocene (first divergence c. 120 ka, second c. 60 ka). Main conclusions : (1) Molecular dating of demographic changes of two African tropical forest tree species is consistent with the Pleistocene forest refuge hypothesis. (2) Tree species from Guinean evergreen tropical forests might have been less affected by past climate change than semi-deciduous species. (3) Our phylogeographical data support a recent date (Holocene) of the last opening of the Dahomey Gap. [less ▲]

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See detailLate Quaternary clay mineral record in Central Lake Baikal (Academician Ridge, Siberia)
Fagel, Nathalie ULg; Boski, T.; Likhoshway, L. et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2003), 193(1), 159-179

We investigated the mineralogical composition of two cores recovered on the Academician Ridge (Central Lake Baikal, Siberia). Sedimentological features show that the cores are unaffected by turbidity ... [more ▼]

We investigated the mineralogical composition of two cores recovered on the Academician Ridge (Central Lake Baikal, Siberia). Sedimentological features show that the cores are unaffected by turbidity currents. However, hemipelagic deposition is not continuous, but intermittently disturbed by syn- or post-sediment reworking (e.g., bioturbation, slumps, faulting). Such modes of deposition are consistent with the complex uplift history of the ridge. Bulk mineralogy suggests that terrigenous sediment supplies are constant through glacial/interglacial stages, and diluted by diatom-rich intervals related to warmer interglacial stages. The core stratigraphy is based on the correlation of the diatom zonation and opal abundance with the marine oxygen isotope reference curve SPECMAP. The similar to 8-m cores partly recover the last four interglacial/glacial cycles, i.e., since oxygen isotope stage 8. We test the use of clay minerals as a proxy for paleoclimatic reconstruction. The clays are more weathered during the diatom-rich intervals in agreement with warmer climate conditions. However, the mean clay composition does not change significantly through glacial/interglacial stages. This observation implies that, in the Academician Ridge sediments, a simple smectite/illite ratio (S/I) does not alone provide a reliable indicator of climatic variation. It reflects the complex clay assemblages, especially the smectite group, delivered to Central Lake Baikal. Smectites include primarily illite-smectite mixed layers, made of a mixture of montmorillonite and beidellite. According to their behavior after cation saturation, the illite-smectite mixed layers are primarily transformed smectites, with some neoformed smectites intermittently observed. In addition, Al-smectites occur in minor proportions. We conclude that the S/I ratio has a climatic significance only if it evolves in parallel with the weathering stage of the clays and is confirmed by a change in the composition of the smectites. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailLate Quaternary climatic changes in southern Chile, as recorded in a diatom sequence of Lago Puyehue (40 degrees 40 ' S)
Sterken, Mieke; Verleyen, Elie; Sabbe, Koen et al

in Journal of Paleolimnology (2008), 39(2), 219-235

A late Quaternary diatom stratigraphy of Lago Puyehue (40 degrees 40'S, 72 degrees 28'W) was examined in order to infer past limnological and climatic changes in the South-Chilean Lake District. The ... [more ▼]

A late Quaternary diatom stratigraphy of Lago Puyehue (40 degrees 40'S, 72 degrees 28'W) was examined in order to infer past limnological and climatic changes in the South-Chilean Lake District. The diatom assemblages were well preserved in a 1,122 cm long, C-14-dated sediment core spanning the last 17,900 years, and were in support of an early deglaciation of Lago Puyehue. The presence of a short cold spell in South Chile, equivalent to the Younger Dryas event in the Northern Hemisphere, the Antarctic Cold Reversal in Antarctica, or the Huelmo-Mascardi event in southern South America, was not clearly evidenced in the diatom data, although some climate instability may have occurred between 13,400 and 11,700 cal. yr. BP, and a relatively long period (between 16,850 and 12,810 cal. yr. BP) with low absolute abundances and biovolumes could be tentatively interpreted as a period of low rainfall and/or temperatures. An increase in the moisture supply to the lake was tentatively inferred at 12,810 cal. yr. BP. After 9,550 cal. yr. BP, inferred stronger and longer persisting summer stratification, may have been the result of the higher temperatures associated with an early-Holocene thermal optimum. The mid-Holocene appeared to be characterized by a decrease in precipitation, culminating around 5,000 cal. yr. BP, and rising again after 3,000 cal. yr. BP, likely associated with a previously documented lowered frequency and amplitude of El Nino events. An increase in precipitation during the late Holocene (3,000 cal. yr. BP-present) might have marked subsequent increased frequency of El Nino occurrences, leading to drier summers and slightly moister winters in the area. [less ▲]

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See detailLate Quaternary evolution of sediment provenances in the Central
Fagel, Nathalie ULg; Not, Christelle; Gueibe, Jonathan et al

in Quaternary Science Reviews (2014), 92

Mineral assemblage, trace element content and Nd and Pb isotope signatures were analysed on the fine fraction (<20 mm) of sedimentary records from the Northern Mendeleev Ridge in the Central Arctic Ocean ... [more ▼]

Mineral assemblage, trace element content and Nd and Pb isotope signatures were analysed on the fine fraction (<20 mm) of sedimentary records from the Northern Mendeleev Ridge in the Central Arctic Ocean. Our aimwas to identify the detrital particle provenance and to interpret the changes over the past w250 ka in the relative contribution of the different source-areas in relation to paleoenvironmental conditions. The clay mineral assemblage and the Nd and Pb isotope signatures depict systematic changes over the Late Quaternary. The bulk mineralogy exhibits increases in the relative contribution of carbonate minerals vs. silicates in interglacial/deglacial intervals. In glacial intervals, the mineral assemblage of the <20 mm fraction is characterised by an enrichment in kaolinite, counterbalanced by a decrease in illite. The Nd and Pb isotope signatures of <20 mm fraction are interpreted using a three end-member mixing model, involving crustal supplies from North America and Canada, from the Siberian margin and some from volcanic material. A compilation of geochemical signatures of geological terraines surrounding the Arctic Ocean allowed each end-member to be assigned a representative signature, averaging the signal of the eroded terraines. The Suspended Particulate Matter (SPM) of the MacKenzie River represents an average signature of the sedimentary supplies delivered from the North American platform and Canadian margin. The SPM of the Lena River reflects the mean sedimentary signature of the Siberian platform. The Okhotsh-Chukotka province from the Eastern border of Siberia is identified as the most probable volcanic source. Late Quaternary evolution of the estimated relative contribution of the three end-members confirms that the sediment provenances in the Central Arctic Ocean remain close to the current conditions during past interglacials/deglacials MIS1e3, MIS5/TII and MIS7/TIII. In contrast, glacial conditions (MIS4 and MIS6) record minimum supplies from the American margin, associated with increased volcanic contribution, to the Mendeleev Ridge core location suggesting a different sea-ice circulation associated with a low sea-level and reduced shelf area. [less ▲]

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See detailThe Late Quaternary History of Biogeochemical Cycling of carbon
Pedersen; François, R.; François, Louis ULg et al

in Alverson, K. D.; Bradley, R. S.; Pedersen, T. F. (Eds.) Paleoclimate, Global Change and the Future (2003)

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See detailLate Quaternay sedimentation and active faulting in the Western tip of the Gulf of Corinth, Greece
Hubert, Aurelia ULg; Beckers, Arnaud ULg; Beck, Christian et al

Poster (2013, November 06)

The Gulf of Corinth is one of the fastest-spreading intracontinental rifts on Earth. Present day kinematics (GPS data) indicates an opening direction oriented NNE-SSW and an opening rate increasing ... [more ▼]

The Gulf of Corinth is one of the fastest-spreading intracontinental rifts on Earth. Present day kinematics (GPS data) indicates an opening direction oriented NNE-SSW and an opening rate increasing westward from 11 mm y-1 in the central part to 16 mm y-1 in the westernmost part. A significant part of the deformation is localized offshore, where the fault geometry was not well known yet. The high extension rate would imply a high seismic hazard if faults are not creeping. We propose an accurate map of submarine faults in the western extremity of the Gulf of Corinth. The map is based on two high-resolution seismic reflection surveys (single channel sparker) performed aboard HCMR’s R/V ALKYON, within the frame of SISCOR ANR Project. About 600 km of seismic lines were acquired, with a 200 msTWTT maximum penetration down to what we infer to represent the MIS 5 discontinuity. Depocenters location is controlled by river deltas where up to 75m of post-LGM sediments are stored. Numerous, up to 15m thick, mass transport deposits fill the central and eastern parts. In the eastern part, the sedimentary infill is faulted by the known North Eratini, South Eratini and West Channel faults. At the longitude of the Trizonia Island, the seafloor in mainly horizontal and the only fault is the south dipping Trizonia fault. Between the Trizonia Island and the Mornos Delta, the shallower northern part of the gulf shows a diffuse pattern of deformation with faults striking mainly E-W and ESE-WNW. It shows south and north dipping normal faults, strike-slip faults, as well as an inherited basement relief. To the West, three young grabens have been identified, striking NE-SW and W-E. The northern, 6 km long, fault in this grabens system shows a clear strike-slip component (fig.1). [less ▲]

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See detailLate Recurrence of Ischemic Mitral Regurgitation after Restrictive Annuloplasty: Is LV Remodeling the Sole Mechanism?
Sénéchal, M; Magne, Julien ULg; Dumesnil, JG et al

Conference (2007)

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See detailLate Rupture of a Saphenous Vein Aortorenal Graft
Lavigne, Jean-Paul ULg; Keppenne, Véronique ULg; Limet, Raymond ULg

in Journal of Vascular Surgery (1999), 29(4), 722-3

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See detailLate Tournaisian (Carboniferous) brachiopods from Mouydir (Central Sahara, Algeria)
Mottequin, Bernard ULg; Legrand-Blain, Marie

in Geological Journal (2010), 45

A small-sized brachiopod fauna, representing an orthid, rhynchonellid and spiriferid community which lived in a low-energy environment, is reported from the lower part of the Argiles de Teguentour and was ... [more ▼]

A small-sized brachiopod fauna, representing an orthid, rhynchonellid and spiriferid community which lived in a low-energy environment, is reported from the lower part of the Argiles de Teguentour and was collected around Oued Tamertasset (or Temertasset) and Oued Habadra in north-western Mouydir (Algerian Sahara). Associated goniatites indicate an early Late Tournaisian age (Pericyclus–Progoniatites assemblage). Thirteen brachiopod species belonging to 12 genera and 5 orders (Productida, Orthida, Rhynchonellida, Athyridida and Spiriferida) are described. Mouydirhynchus is proposed as a new rhynchonellid genus and the species Rhipidomella prolifica, Mouydirhynchus quietus and Eomartiniopsis mouydirensis are new. The other described taxa are the following: Chonetipustula? sp., strophalosioid gen. et sp. indet., Schizophoria sp., trigonirhynchiid gen. indet. sp. A, trigonirhynchiid gen. indet. sp. B, Hemiplethorhynchus? sp., Coveenia? sp., Crurithyris cf. fissa, Punctothyris? sp., and elythid gen. et sp. indet. [less ▲]

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See detailThe Late Viséan Rugose coral association of NW Turkey
Denayer, Julien ULg

in Bernecker, Michaela (Ed.) 12th International Symposium on Fossil Cnidaria and Porifera 2015 - Abstract Volume (2015, February)

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See detailLate-Holocene moist forests of Central Africa: contribution of charcoal analysis
Morin, Julie ULg; Bremond, Laurent; Gillet, Jean-François et al

Poster (2014, December)

Wood charcoals are often uncovered in the soils of the tropical regions. They remain little studied, however, and this observation is even truer for charcoals coming from the dense humid forests of ... [more ▼]

Wood charcoals are often uncovered in the soils of the tropical regions. They remain little studied, however, and this observation is even truer for charcoals coming from the dense humid forests of Central Africa. Here we aim at showing the interest of the analysis of soil charcoals in this region so as to understand the dynamics of past forest environments during the late-Holocene. Several examples of taxonomical identifications conducted on charcoals sampled in soil pits in Cameroon and in the Republic of the Congo are presented along with radiocarbon dates. These charcoals were hand-split then observed under an incident light microscope. The wood anatomical features that were preserved in charcoals and described according to a standard method were compared to a reference collection of woods. Results demonstrated that past burnings that spanned from 2,500 BP to Recent were human-induced and scattered in the study area. The identified species are still present in the environment today and localized changes in the vegetation occurred over the past two millennia. Charcoal analysis can thus allow a better understanding of the past history of the tropical forests in relationship with the ancient anthropogenic disturbances. [less ▲]

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See detailLate-Holocene tropical moist-forests of southeastern Cameroon: some insight from soil charcoal analysis
Morin, Julie ULg; Biwolé, Achille; Bourland, Nils et al

Conference (2015, August)

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. Little is known, however, about past vegetation in this region that remains underexplored ... [more ▼]

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. Little is known, however, about past vegetation in this region that remains underexplored (Vleminckx et al. 2014; Morin-Rivat et al. 2014). Determining the past specific composition of these forests could allow bringing insights into their evolution over time and providing data about their resilience capacity facing global change. We performed a pedoanthracological analysis in the semi-deciduous forests of southeastern Cameroon. We excavated 53 test pits of 53 50 × 50 × 60 cm in plots of botanical inventory along a NS 80-km long mega-transect that followed a vegetation gradient. We sorted and quantified charred macrobotanical remains by layers of 10 cm, then identified species from wood charcoals. We used the InsideWood database, implemented with 163 new anatomical descriptions of woods present in the study area by using the reference collection of African woods of the Royal Museum for Central Africa (Belgium). Finally, we obtained 25 radiocarbon dates on charcoals and oil palm endocarps. Results showed that repeated fire events occurred across the study area during the last 2500 years, soon after the well-documented “rainforest crisis” (e.g. Lézine et al. 2013). The analyzed charcoals are likely human-induced regarding evidence of associated human settlements (e.g. potsherds). Aged were distributed into two time periods: the Early Iron Age (2300-1300 BP) and the Late Iron Age (700-100 BP) with an intermediate hiatus in human occupation (see e.g. Wotzka 2006; Morin-Rivat et al. 2014). Specific composition during both periods did not strongly differ from current composition, which is now dominated by light-demanding canopy trees belonging to old-growth semi-deciduous Celtis forests (Gond et al. 2013; Fayolle et al. 2014). This argues in favor of the maintenance of light-demanding tree species by anthropogenic activities, such as slash-and-burn shifting cultivation. We conclude that moist forests have a good resilience capacity regarding moderate and scattered disturbances. These forests can nonetheless be deeply impacted by land-use intensification (e.g. degraded forests along roads and close to cities; Gond et al. 2013). [less ▲]

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See detailDie lateinischen Papyri als Quellen des Vulgärlateins
Macedo, Gabriel ULg

Scientific conference (2013, May 08)

Detailed reference viewed: 28 (2 ULg)