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See detailModelling the evolution of climate and sea level over the third millennium (MILMO)
Fichefet, Thierry; Driesschaert, Emmanuelle; Goosse, Hugues et al

Report (2007)

A new three-dimensional Earth system model of intermediate complexity was developed. This model, named LOVECLIM, consists of five major components representing the atmosphere (ECBilt), the ocean and sea ... [more ▼]

A new three-dimensional Earth system model of intermediate complexity was developed. This model, named LOVECLIM, consists of five major components representing the atmosphere (ECBilt), the ocean and sea ice (CLIO), the terrestrial biosphere (VECODE), the oceanic carbon cycle (LOCH) and the Greenland and Antarctic ice sheets (AGISM). It also includes a global glacier-melt algorithm which is run in off-line mode. It is worth mentioning that there are very few models of this type worldwide. ECBilt is a quasi-geostrophic atmospheric model with 3 levels and a T21 horizontal resolution. It includes simple parameterisations of the diabatic heating processes and an explicit representation of the hydrological cycle. Cloud cover is prescribed according to present-day climatology. CLIO is a primitive-equation, free-surface ocean general circulation model coupled to a thermodynamic–dynamic sea-ice model. Its horizontal resolution is 3° × 3°, and there are 20 levels in the ocean. VECODE is a reduced-form model of vegetation dynamics and of the terrestrial carbon cycle. It simulates the dynamics of two main terrestrial plant functional types (trees and grassland) at the same resolution as that of ECBilt. LOCH is a comprehensive model of the oceanic carbon cycle that takes into account both the solubility and biological pumps. The version utilised here has the same resolution as the one of CLIO, which greatly facilitates the coupling between both models. Finally, AGISM is composed of a three-dimensional thermomechanical model of the ice sheet flow, a visco-elastic bedrock model and a model of the mass balance at the ice–atmosphere and ice–ocean interfaces. The Antarctic ice-sheet module also contains a model of the ice-shelf dynamics to enable interactions with the ocean and migration of the grounding line. For both ice sheets, calculations are made on a 10 km × 10 km resolution grid with 31 sigma levels. The performance of LOVECLIM was assessed by conducting ensemble simulations over the last few centuries. Starting from different initial conditions, the model was integrated from year 1500 AD up to year 2000 AD with solar irradiance, volcanic activity, tropospheric ozone amount, greenhouse-gas (including CO2) concentrations and sulphate-aerosol load evolving with time according to reconstructions. Over the last 140 years, the model simulates a global surface warming ranging from 0.33°C to 0.43°C, with a mean value of 0.38°C. This value is about 0.15°C lower than the observed one. A detailed analysis of the results has revealed the model behaves reasonably well at mid- and high latitudes. By contrast, at low latitudes, the agreement between the model results and observational estimates is less good, especially in the Southern Hemisphere. In those regions, LOVECLIM significantly underestimates the warming and the climate variability observed during the last few decades. The coarse resolution of the model and the simplified representation of the atmospheric dynamical and physical processes seem to be the two major candidates responsible for this deficiency. Regarding the Greenland ice sheet, we found a slightly increasing ice volume during the period 1700–2000 AD. This trend is largely explained as a residual response to the late Holocene forcing, in particular to the Little Ice Age cooling after year 1500 AD. The effect is not particularly large, however, amounting to only 1.2 cm of global sea-level rise over the entire period. The growing trend stabilizes during the 20th century, with almost no net effect on ice volume. Only during the last decades of the 20th century, the ice volume begins to decrease in response to the imposed warming. We also found the Antarctic ice sheet to be retreating slowly at a rate equivalent to a global sea-level rise of about 1.7 cm during the 20th century. This evolution is mostly due to a long-term background trend of +2.6 cm, mitigated by about 0.9 cm from slightly rising accumulation rates over the same period. The ongoing dominance of past climatic changes on the contemporary ice-sheet evolution is a fine illustration of the inertia encountered when studying the response of large continental ice sheets. In this case, it mainly results from an ongoing grounding-line retreat in West Antarctica following rising sea levels since the Last Glacial Maximum. As far as mountain glaciers and small ice caps are concerned, their area and volume are found to reach a maximum in the late 19th century corresponding to the Little Ice Age, but this maximum and the ensuing 20th century glacier retreat are not very pronounced. Over the last hundred years, the model simulates an ice loss equivalent to only 0.89 cm of sea-level rise. This value is at the lower end compared to other assessments. One reason is the low total ice volume assumed by the global glacier-melt algorithm (about 20 cm of total sea-level rise, a factor 2.5 less than previous estimates). A second reason is the prescribed global ice mass balance for the 1961–1990 reference period, which is also at the lower end of other simulations. For the 20th century, LOVECLIM explains about 7.6 cm of sea-level rise. The bulk of that value, about 4.7 cm, comes from thermal expansion of the World Ocean. The Antarctic and Greenland ice sheets combined lead to a sea-level rise of 2 cm, and glaciers and ice caps are responsible for about 0.9 cm of sea-level rise. These numbers are similar to those that have been derived for the IPCC Third Assessment Report (TAR) for the same components except for the lower glacier contribution as found here. Over the industrial era, the net uptake of carbon by the ocean simulated by LOVECLIM is within the range of current estimates, although at the lower end of this range. It should be noted that a detailed evaluation of the performance of the terrestrial carbon-cycle module was impossible to perform given the very wide range of available data. Experiments with interactive atmospheric CO2 concentration were also carried out with LOVECLIM forced by CO2 emissions from fossil fuel burning and land-use change. Interestingly enough, the atmospheric CO2 level computed by the model in year 2000 AD compares relatively well with the observed one. A series of climate-change projections were then conducted over the 21st century. In these experiments, LOVECLIM was driven by changes in greenhouse-gas (including CO2), tropospheric ozone and sulphate-aerosol concentrations following the IPCC SRES scenarios B1, A1B and A2. In year 2100 AD, the model predicts a globally averaged, annual mean surface warming of 1°C, 1.4°C and 1.8°C for scenarios B1, A1B and A2, respectively, and an associated increase in precipitation of 3.6%, 5.1% and 6.6%, respectively. In agreement with studies performed with climate general circulation models (CGCMs), a weakening of the Atlantic meridional overturning circulation (MOC) is noticed in all runs. At the end of the 21st century, the decrease in the maximum value of the annual mean meridional overturning streamfunction below the surface layer in the Atlantic basin, which is an index of the MOC intensity, reaches 19% for scenario B1, 21% for scenario A1B and 27% for scenario A2. In our model, as in the majority of CGCMs, this decrease is caused more by changes in surface heat flux than by changes in surface freshwater flux. Under the forcing scenario A1B, LOVECLIM simulates a global sea-level rise of 31.3 cm in year 2100 AD. As for the 20th century, the most important contributor is the oceanic thermal expansion (+18.8 cm), followed by the contributions from the Greenland ice sheet (+5.2 cm), glaciers and ice caps (+3.8 cm) and the Antarctic ice sheet (+3.5 cm). The total rise is equivalent to a quadrupling of the sea-level rise simulated for the 20th century. Our sea-level value is somewhat lower than the central estimate for the same four components of about 40 cm in the IPCC TAR predictions. This can be explained by the low climate sensitivity of LOVECLIM, and hence the lower global temperature rise, which mostly affects the largest contribution of thermal expansion of the World Ocean. Another difference with the IPCC TAR predictions is the positive contribution from Antarctica of several cm of sea-level rise. That is in contrast to most other simulations showing a growing ice sheet and a negative contribution to global sea level of typically between -5 and -20 cm. The IPCC TAR also found a generally larger contribution from mountain glaciers and small ice caps. Our glacier-volume loss is smaller because of the lower initial glacier volume assumed by the glacier-melt algorithm. The total projected sea-level rise for the 21st century is only slightly affected by the scenario itself. For the range of SRES scenarios used by LOVECLIM, the total sea-level rise is found to vary between +22 and +35 cm by year 2100 AD. The much larger range of between +9 and +88 cm obtained for the IPCC TAR arose mainly from the inclusion of model uncertainties, and not from the greenhouse-gas-forcing scenarios employed. As expected, climate change impacts the air–sea CO2 exchange in the model by lowering the solubility and hence the net uptake of carbon by the ocean. The effect is however rather modest at the century time-scale given the moderate increase in sea-surface temperature simulated by LOVECLIM. In addition, we do not observe any significant change in the oceanic biology at the global scale during the 21st century. The picture is a bit different regarding the terrestrial biosphere. Both the climate and fertilization effects strongly increase the carbon uptake in VECODE. A number of experiments with interactive atmospheric CO2 concentration were also carried out over the 21st century. Contrary to other modelling studies, LOVECLIM predicts lower atmospheric CO2 levels at the end of the 21st century when the effect of climate change on the carbon cycle is accounted for in the model. The warming enhances the net uptake of carbon by the terrestrial biosphere which more than offsets the reduction in oceanic uptake resulting from the solubility decrease. Finally, we have thoroughly analysed the model response to a range of stabilized anthropogenic forcings over the next millennia. For the variety of forcing scenarios considered, LOVECLIM simulates a globally averaged, annual mean surface warming ranging between 0.55°C and 3.75°C and an associated decrease in Arctic and Antarctic sea-ice extent. However, no simulation predicts an entirely ice-free Arctic Ocean during summertime at the millennium time-scale. In the most pessimistic case, a small ice pack of about 0.5×106 km2 persists. Our results also suggest that it is very likely that the volume of the Greenland ice sheet will largely decrease in the future. After 1000 years of model integration, the ice volume is reduced by more than 20% when the radiative forcing is higher than 6.5 W m-2. Moreover, for a radiative forcing greater than 7.5 W m-2, the ice sheet melts away in less than 3000 years. Note that the ice-sheet disintegration might be even more rapid if processes responsible for the widespread glacier acceleration currently observed in Greenland were taken into consideration in the model. We also found that the freshwater flux from the melting Greenland ice sheet into the neighbouring oceans, which peaks in the most extreme scenario tested at 0.11 Sv (1 Sv = 10^6 m3 s-1) and remains above 0.1 Sv during three centuries, is not large enough to trigger a shutdown of the Atlantic MOC in our model, in contrast to some other models. Those models are however more responsive to freshwater perturbations than ours. Besides, we showed that climate feedbacks play a crucial role in the ice-sheet evolution and that the Greenland deglaciation considerably enhances the greenhouse-gas-induced warming over Greenland and the central Arctic. This stresses the importance of incorporating the two-way interactions between the Greenland ice sheet and climate in climate- and sea-level-change projections at the millennial time-scale. For the Antarctic ice sheet, the response is much less drastic than for the Greenland ice sheet. For instance, after 3000 years of 4×CO2 forcing (∼7.7 W m-2), the Antarctic grounded ice volume and area are reduced in our model by only 8% and 4%, respectively. For a sustained radiative forcing of 8.5 W m-2 (the highest forcing scenario considered in our study), LOVECLIM predicts a global sea-level rise of 7.15 m by year 3000 AD. Most of it is due to melting of the Greenland ice sheet (+4.25 m), followed by melting of the Antarctic ice sheet (+1.42 m), thermal expansion (+1.29 m) and the contribution from mountain glaciers and small ice caps (+0.19 m). Our results show that it will be very difficult to limit the eventual sea-level rise to less than 1 m after 1000 years, unless the atmospheric CO2 concentration can be stabilized to less than twice its pre-industrial level. Such a goal can only be reached by emission reductions far larger than any policy currently pursued. Concerning the carbon cycle, the experiments carried out with LOVECLIM highlight the opposite responses of the terrestrial and oceanic carbon reservoirs to climate change. We also found that, when anthropogenic CO2 emissions cease, the terrestrial biosphere becomes a weak carbon source, while the ocean continues to be a sink. It should be mentioned that no dramatic change in the global marine productivity is observed in our simulations. This arises from the fact that the modifications of the oceanic properties that affect this productivity (stratification, meridional overturning, …) are rather moderate. The effects of climate change are however not negligible. In particular, the decrease in sea-ice extent predicted by the model results in a longer growing season and a larger nutrient uptake (especially silica) in polar regions. As a result, by the end of the 23rd century, silica concentrations in the upper 100 m of the Southern Ocean drop by as much of 30% for the most extreme forcing scenarios. [less ▲]

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See detailValidating the MODIS LAI product by scaling up LAI measurements at a VALERI Alpine Meadow site, China.
Ma, M; Veroustraete, F; Lu, L et al

in Survey Review (2007), 39

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See detailProject Office – Mid-term progress report
Warnant, René ULg

Report (2007)

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See detailLe traitement du diabète de type 2: entre insulinosensibilisateurs et insulinosécrétagogues
Scheen, A. J.; Radermecker, R. P.; Philips, J. C. et al

in Revue Médicale de Liège (2007), 62 Spec No

Type 2 diabetes is a complex disease characterized by a dual defect of insulin secretion and insulin sensitivity, which may vary from patient to patient, but also along the natural history of the disease ... [more ▼]

Type 2 diabetes is a complex disease characterized by a dual defect of insulin secretion and insulin sensitivity, which may vary from patient to patient, but also along the natural history of the disease in a particular patient. Besides the lifestyle changes, the treatment strategy comprises the administration of agents that promote insulin secretion and/or that improve insulin sensitivity. Drugs facilitating weight loss also improve glucose control by reducing insulin resistance. A global approach should be recommended to reduce the high cardiovascular risk of diabetic patients. The present article aims at summarizing our contribution to the development of drugs designed for the treatment of type 2 diabetes. [less ▲]

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See detailFractal analysis of intraflow unidirectional delay over w-lan and w-wan environments
Pezaros, D. P.; Sifalakis, M.; Mathy, Laurent ULg

in Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks and Workshops, 2007. WiOpt 2007. 5th International Symposium on (2007)

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See detailIsolation and evaluation of bacteria and fungi as biological control agents against Rhizoctonia solani.
Lahlali, R.; Bajii, M.; Jijakli, Mohamed ULg

in Communications in agricultural and applied biological sciences (2007), 72(4), 973-982

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See detailPhase distribution measurements in metallic foam using x-ray radiography and micro-tomography
Toye, Dominique ULg; Aferka, Saïd ULg; Calvo, Sébastien ULg et al

in Johansen, G. A.; Mc Cann, H. (Eds.) Proceedings of the 5th World Congress on Industrial Process Tomography, Bergen, Norway, September 6-9, 2007 (CD-ROM) (2007)

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See detailIsaac Bashevis Singer, ou la littérature comme illustration d'une théorie du droit
Thirion, Nicolas ULg

in Liber amicorum Paul Martens. L'humanisme dans la résolution des conflits. Utopie ou réalité? (2007)

Illustration de la théorie de la pluralité des ordres juridiques de Santi Romano par une nouvelle d'Isaac Bashevis Singer tiré du recueil "Au tribunal de mon père"

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See detailBenefits of an out-patient multidisciplinary rehabilitation program in the treatment of chronic low back pain
Vanderthommen, Marc ULg; Demoulin, Christophe ULg; GROSDENT, Stéphanie ULg et al

in Abstract book of 6th Interdisciplinary World Congress on Low Back & Pelvic Pain (2007)

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See detailThermomechanical one-phase modeling of semi-solid thixoforming
Koeune, Roxane ULg; Ponthot, Jean-Philippe ULg

in Int. Conf. on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2007 (2007)

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See detailEtude de l’impact de l’activité de la pêche artisanale et de l’effet de gestion sur les populations d’Epinephelus marginatus (Lowe 1834) dans le périmètre de la Réserve Naturelle des Bouches de Bonifacio
Garrido, Marie ULg

Master of advanced studies dissertation (2007)

L’objectif de cette étude est de mettre en évidence l’impact du filet trémail et de la palangre concernant la pêche professionnelle sur le mérou brun Epinephelus marginatus (Lowe, 1834) dans la Réserve ... [more ▼]

L’objectif de cette étude est de mettre en évidence l’impact du filet trémail et de la palangre concernant la pêche professionnelle sur le mérou brun Epinephelus marginatus (Lowe, 1834) dans la Réserve Naturelle des Bouches de Bonifacio. C’est à l’aide de la base de données, représentée par des fiches de pêche de 1992 à 2006, que ce travail a pu être réalisé. Les données acquises ont été analysées au moyen du logiciel «Statistica». Afin d’évaluer les différences significatives entre les moyennes des Captures Par Unité d’Effort en fonction de diverses variables. Considérant qu’une palangre est constituée de 104 hameçons (moyenne de l’échantillonnage), on estime la rentabilité moyenne journalière de cet engin à 1560 grammes de mérous. Or la rentabilité moyenne quotidienne d’un filet trémail est de 820 grammes de mérous, pour une longueur moyenne de 1640 mètres dans la RNBB. Malgré l’augmentation progressive de la population d’E. marginatus (taux capture en augmentation de 55% en 2004-2006), l’impact de la pêche à la palangre pourrait se révéler non négligeable, si elle n’était pas réglementée. Les CPUE, en termes de biomasse, sont plus importantes d’années en années, ce qui semble témoigner de la bonne santé de la pêche dans l’extrême sud de la Corse grâce à une gestion durable des stocks. [less ▲]

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See detailVoltage rectification effects in mesoscopic superconducting triangles: Experiment and modeling
Schildermans, N.; Kolton, A. B.; Salenbien, R. et al

in Physical Review. B : Condensed Matter (2007), 76(22),

The interaction of externally applied currents with persistent currents induced by magnetic field in a mesoscopic triangle is investigated. As a consequence of the superposition of these currents, clear ... [more ▼]

The interaction of externally applied currents with persistent currents induced by magnetic field in a mesoscopic triangle is investigated. As a consequence of the superposition of these currents, clear voltage rectification effects are observed. We demonstrate that the amplitude of the rectified signal strongly depends on the configurations of the current leads with the lowest signal obtained when the contacts are aligned along a median of the triangle. When the contacts are aligned off centered compared to the geometrical center, the voltage response shows oscillations as a function of the applied field, whose sign can be controlled by shifting the contacts. These results are in full agreement with theoretical predictions for an analogous system consisting of a closed loop with a finite number of identical Josephson junctions. [less ▲]

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See detailPeaufiner la dermatopathologie fonctionnelle, la dermometrologie et la mecanobiologie.
Pierard, Gérald ULg; Pierard, Claudine ULg; Hermanns-Lê, Trinh ULg et al

in Revue Médicale de Liège (2007), 62 Spec No

Dermatopathology is a tool using the microscopic examination for diagnosing cutaneous diseases. The frontiers of its field of interest were extended by exploring the physiopathology of skin functional ... [more ▼]

Dermatopathology is a tool using the microscopic examination for diagnosing cutaneous diseases. The frontiers of its field of interest were extended by exploring the physiopathology of skin functional properties. An example is provided by the evaluation of alterations of skin suppleness in various connective tissue disorders. This approach takes profit from both conventional histology and histochemistry. Immunohistology targeting dermal dendrocytes reveals their various shapes reflecting the modifications in tensegrity under the control of mechanobiology. The latter property is an indicator of the evolution and severity of the connective tissue changes. Electron microscopy is also very instructive in this field. The in vivo examination by dermoscopy highlights a similar mechanism involving the melanocytes. From an engineering point of view, the skin and subcutaneous tissue represent an integrated load-transmitting structure. It is subjected to intrinsic and environmental influences. Some models were offered to explain how skin withstands and transmits loads through deforming appropriately or abnormally according to disorders of the connective tissue structure. We report a brief review of the principles of interpretation of the measurements of the skin biomechanical properties, and the histological presentations of mechanobiology. The applications of such investigations are summarized in the Ehlers-Danlos syndrome, inguinal hernias, gravitational syndrome, diabetes, scleroderma, hemodialysed patients, in case of growth hormone administration and during climacteric. [less ▲]

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See detailA Reputation-Based Approach for Securing Vivaldi Embedding System
Saucez, Damien; Donnet, Benoît ULg; Bonaventure, Olivier

in 13th Conference on Dependable and Adaptable Networks and Services (2007)

Many large-scale Internet applications optimize their overlay network to reduce latencies. Embedding coordinate systems like Vivaldi are valuable tools for this new range of applications since they ... [more ▼]

Many large-scale Internet applications optimize their overlay network to reduce latencies. Embedding coordinate systems like Vivaldi are valuable tools for this new range of applications since they propose light-weight algorithms that permit to estimate the latency between any pair of nodes without having to contact them first. It has been recently demonstrated that coordinate systems in general and Vivaldi in particular are sensible to attacks. Typically, nodes can lie about their coordinate and distort the coordinate space. In this paper, we propose a formal reputation model to detect misbehaving nodes and propose a reputation adaptation of Vivaldi called RVivaldi. We evaluate the performance of RVivaldi using the King dataset and show that RVivaldi is less sensitive to malicious nodes than Vivaldi. [less ▲]

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See detailRecent land dynamics in the Tonle Sap Flood Plain and its impacts on the local communities
Diepart, Jean-Christophe ULg

in Tonle Sap Biosphere Reserve Bulletin (2007), 3

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See detailToxoplasma encephalitis after autologous stem cell transplantation.
Grosu, Irina; Ghekiere, Olivier; LAYIOS, Nathalie ULg et al

in Leukemia & Lymphoma (2007), 48(1), 201-3

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See detailCharge order superstructure with integer iron valence in Fe2OBO3
Angst, M.; Khalifah, P.; Hermann, Raphaël ULg et al

in Physical Review Letters (2007), 99(8),

Solution-grown single crystals of Fe2OBO3 were characterized by specific heat, Mossbauer spectroscopy, and x-ray diffraction. A peak in the specific heat at 340 K indicates the onset of charge order ... [more ▼]

Solution-grown single crystals of Fe2OBO3 were characterized by specific heat, Mossbauer spectroscopy, and x-ray diffraction. A peak in the specific heat at 340 K indicates the onset of charge order. Evidence for a doubling of the unit cell at low temperature is presented. Combining structural refinement of diffraction data and Mossbauer spectra, domains with diagonal charge order are established. Bond-valence-sum analysis indicates integer valence states of the Fe ions in the charge ordered phase, suggesting Fe2OBO3 is the clearest example of ionic charge order so far. [less ▲]

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See detailA reference section for neritic facies at the transition Late to Latest Famennian.
Streel, Maurice ULg; Maziane-Serraj, N; Marshall, JEA et al

in Subcommission on Devonian Stratigraphy Newsletter (2007), 22

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