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See detailRecent state of the Aral sea from regular satellite observations. 35th COSPAR Scientific Assembly
Stanichny, Sergey ULg; Davidov, A.; Djenidi, Salim ULg et al

in 35th COSPAR Scientific Assembly (2004)

The Aral Sea disaster is one of the most significant examples of ecological catastrophe caused by mismanagement of water resources. Aral sea level dropped on 22 meters for the last 35 years. The sea ... [more ▼]

The Aral Sea disaster is one of the most significant examples of ecological catastrophe caused by mismanagement of water resources. Aral sea level dropped on 22 meters for the last 35 years. The sea separated in to two independent parts , the Large Sea(Southern) and the Small Sea (Northern), loosing more than 90% of its original water masses. After the collapse of the former Soviet Union, satellite retrieved data became the main source of information on this perishing system. Regular observations from AVHRR, SeaWiFS, MODIS and ASTER satellite sensors were used for our investigations. Sea surface temperature (SST) data of the AVHRR sensor and digital bottom map topography were used for sea level drop calculations. The Sea level defined as the digital map isobate corresponds quite well to the satellite derived coastline for the Eastern part of the Large Sea with a bottom slope of ˜ 0.00015. For the period 1989-2002 the sea level of the Large Sea dropped on 9.2 meters. However in 2003 the sea level remained stable. This stabilisation was due to an increase of water output of the rivers Amu--Darya and Syr-Darya in 2003. High resolution ASTER data showed that the main amount of Syr-Darya waters is discharged into the Large Sea. The dried bottom area now covers more than 45000 km2. On the base of AVHRR-SST data the temperature regime for different parts of the Aral Sea was calculated for the years 2002-2003. The annual amplitude of the SST variation reaches 37° C for the open waters. The observed minimum freezing point was -7° C due to very high salinity. Estimations from satellite retrieved freezing points show an increase of salinity up to 10% in the Eastern part of the Large Sea. It is almost paradox that on satellite images the ice appears warmer than the water. Strong variations of the water temperature (up to 5° C) within a few days could be observed from April to August and could be related to wind induced mixing. SeaWiFS ocean colour data were used for the investigation of the optical properties of the water in different parts of the Aral Sea for the years 2002-2003. A significant relation of optical properties with wind and temperature was obtained. Strong changes of the thermal regimes of the Sea can cause variations in local climatic conditions: The analysis of AVHRR NDVI - data for the surrounding areas demonstrated a shift in the annual vegetation cycle. In addition phenomena like: salt storms, wind driven tides, sources of groundwater, eddies and frontal structures as well as ice coverage of the Aral Sea were demonstrated on satellite images. [less ▲]

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See detailUne approche statistique de la concurrence entre démonstratifs chez les historiens latins (César, Salluste, Tacite)
Longrée, Dominique ULg

in Bodelot, Colette (Ed.) Anaphore, cataphore et corrélation en latin, Actes de la Journée d'étude de Linguistique latine, Université Blaise Pascal - Clermont-Ferrand 2, 7 janvier 2003 (2004)

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See detailGas transfer velocities of CO2 in three European estuaries (Randers Fjord, Scheldt and Thames)
Borges, Alberto ULg; Delille, Bruno ULg; Schiettecatte, Laure-Sophie et al

in Limnology and Oceanography (2004), 49(5), 1630-1641

We measured the flux of CO2 across the air–water interface using the floating chamber method in three European estuaries with contrasting physical characteristics (Randers Fjord, Scheldt, and Thames). We ... [more ▼]

We measured the flux of CO2 across the air–water interface using the floating chamber method in three European estuaries with contrasting physical characteristics (Randers Fjord, Scheldt, and Thames). We computed the gas transfer velocity of CO2 (k) from the CO2 flux and concomitant measurements of the air–water gradient of the partial pressure of CO2 (pCO2). There was a significant linear relationship between k and wind speed for each of the three estuaries. The differences of the y-intercept and the slope between the three sites are related to differences in the contribution of tidal currents to water turbulence at the interface and fetch limitation. The contribution to k from turbulence generated by tidal currents is negligible in microtidal estuaries such as Randers Fjord but is substantial, at low to moderate wind speeds, in macrotidal estuaries such as the Scheldt and the Thames. Our results clearly show that in estuaries a simple parameterization of k as a function of wind speed is site specific and strongly suggest that the y-intercept of the linear relationship is mostly influenced by the contribution of tidal currents, whereas the slope is influenced by fetch limitation. This implies that substantial errors in flux computations are incurred if generic relationships of the gas transfer velocity as a function of wind speed are employed in estuarine environments for the purpose of biogas air–water flux budgets and ecosystem metabolic studies. [less ▲]

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See detailExtended formulations for Gomory Corner polyhedra
Köppe, Matthias; Louveaux, Quentin ULg; Weismantel, Robert et al

in Discrete Optimization (2004), 1(2), 141-165

We present several types of extended formulations for integer programs, based on irreducible integer solutions to Gomory’s group relaxations. We present algorithmic schemes based on an iterative ... [more ▼]

We present several types of extended formulations for integer programs, based on irreducible integer solutions to Gomory’s group relaxations. We present algorithmic schemes based on an iterative reformulation technique using these extended formulations. We give computational results for benchmark problems, which illustrate the primal and dual effect of the reformulation. [less ▲]

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See detailThe neck domain of myosin V
Terrak, Mohammed ULg; Staford, Walter; Lu, Renne

in Biophysical Journal (2004), 86

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See detailCoton biologique et / ou équitable en Afrique de l'Ouest : Etat des Lieux
Kouakou, Guy Eric Anicet Quassy ULg

Master of advanced studies dissertation (2004)

The biological cotton and / or fair highlights an environment-friendly agriculture(farming) and guaranteeing better income to the farmers.

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See detailLandscape pattern analysis using independent pattern components and landscape transformation processes.
Bogaert, Jan ULg

in The 19th Annual Symposium of the IALE US regional association. (2004)

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See detailLe cas clinique du mois. La syphilis, une MST de retour en nos murs.
Flagothier, Caroline ULg; Arrese Estrada, Jorge ULg; Pierard, Claudine ULg et al

in Revue Médicale de Liège (2004), 59(7-8), 426-9

Sexually transmitted diseases (STD) show frequent epidemiological changes. We report a case of secondary syphilis diagnosed in a 32-year old woman during post-partum. The disease, although showing a ... [more ▼]

Sexually transmitted diseases (STD) show frequent epidemiological changes. We report a case of secondary syphilis diagnosed in a 32-year old woman during post-partum. The disease, although showing a typical presentation, raises the problem of dating with precision the contamination time. This is of importance for treating the newborn at risk of congenital syphilis. We highlight the constant attention that should be brought to disclose this venereal disease that shows so variable clinical and histological presentations. Syphilis seems on the rise in the Mosan valley and in some cities where prostitution is imported from Eastern Europe and Africa. [less ▲]

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See detailCumulative isomerization probability by various transition state wave packet methods including the MCTDH algorithm
Lasorne, Benjamin; Gatti, Fabien; Baloïtcha, Ezinvy et al

in Journal of Chemical Physics (2004), 121

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See detailExecutive functions
Collette, Fabienne ULg; Van der Linden, Martial ULg

in Morris, R. G.; Becker, J. T. (Eds.) The cognitive Neuropsychology of Alzheimer's disease (2004)

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See detailImpact of hydroelectric power releases on the morphology and the sedimentology of the bed of the Warche River (Belgium).
Assani, A. A.; Petit, François ULg

in Earth Surface Processes & Landforms (2004)

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