Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailImpact of global climate change and desertification on the environment and society in Southern Centre of Vietnam (a case study in Binh Thuan province). Climate today and tomorrow: state of play and perception.
Ozer, Pierre ULg

Report (2012)

The Province of Binh Thuan is the driest area of Vietnam. It is felt as being affected by desertification processes that are mainly resulting from the ongoing „climate change‟, especially shortening ... [more ▼]

The Province of Binh Thuan is the driest area of Vietnam. It is felt as being affected by desertification processes that are mainly resulting from the ongoing „climate change‟, especially shortening rainfall. But has climate, and especially precipitations, really changed in recent years? Or is the recent increase of agricultural activities with higher water needs may explain such perception of a changing climate? In the collection of four papers presented hereafter, we try to answer to these questions. Yet, the first paper investigates recent trends in precipitation and temperatures using daily data from the weather station of Phan Thiet. It appears that the area did not experience any significant precipitation decrease (rainfall have, at the contrary, globally increased) but a very significant increase in temperature. The second paper focuses on future climate projections (that is 2046-2065 and 2081-2100 compared to historical data 1970-1999). It shows that the Province of Binh Thuan will face an increase of mean temperature of about 1.6°C (over 2046-2065) and 2.5°C (over 2081-2100) and an increase of extreme temperatures and extreme rainfall events. However, no significant changes about the evolution of the annual amount of precipitation were found. It also indicates that the dry season is likely to be longer in 2046-2065 owing to a delay in the onset of the rainy season (up to 15 days) accompanied by an earlier end of the rainy season (up to 30 days). The third paper explores recent land use and land cover changes in the Province of Binh Thuan. Comparisons of the land cover maps reveal that a steady growth in population has caused extensive changes of land cover throughout the area. The maps also indicate that the loss of woody land (forest) and the extension of irrigated area, combined with built-up encroachment, remains one of the most serious environmental problems today. Yet, results showed over the 12-year span, approximately 115,120 ha of forests were converted respectively to brush, irrigated area, cropland and built-up. This is an overall average decrease of approximately 9,594 ha of forested area per year. Based on the identified causes of these changes, we made policy recommendations for better management of land use and land cover. Such results show that water needs are always increasing due to the extension of irrigated areas. The last paper concludes with a case study of a fishing village disappearing as a result of shoreline erosion. It shows that the term “climate change” is misused probably because it is easier to blame a global issue rather than the local mismanagement of natural resources, the lack of land use planning and the nonexistence of policies focused on natural hazard management in the uncontrolled construction the seaside resort of Mui Ne. This reflexion about the wrong perception of climate change which may cause several economic problems could be extended to water availability which may not be sufficient to support recent developments of irrigated agriculture. Understanding current problems may help developing adaptation strategies in the next decades. Further research is needed to understand such perception of climate change, especially when knowing that future climate may be really affected by an increase of extreme rainfall events and an extended dry season. [less ▲]

Detailed reference viewed: 173 (5 ULg)
Full Text
Peer Reviewed
See detailImpact of global left ventricular afterload on left ventricular function in asymptomatic severe aortic stenosis: a two-dimensional speckle-tracking study.
Lancellotti, Patrizio ULg; Donal, Erwan; Magne, Julien ULg et al

in European Journal of Echocardiography (2010), 11(6), 537-543

Aims: The present study sought to assess the effect of global left ventricular (LV) afterload on LV myocardial systolic function in patients with aortic stenosis (AS) and preserved LV ejection fraction ... [more ▼]

Aims: The present study sought to assess the effect of global left ventricular (LV) afterload on LV myocardial systolic function in patients with aortic stenosis (AS) and preserved LV ejection fraction. <br />Methods and results: We prospectively examined the LV myocardial deformation (i.e. longitudinal, radial, and circumferential) by two-dimensional speckle tracking in 173 patients with asymptomatic severe AS. Thirty-eight patients (22%) had lowflow as determined by a low stroke volume index (􏰀35 mL/m2). By multivariable analysis, four variables emerged as independently associated with low-flow AS: peak Ea velocity (P 1⁄4 0.01), left atrial area index (P 1⁄4 0.017), global LV afterload (P 1⁄4 0.024), and circumferential myocardial deformation (P 1⁄4 0.04). Forty-nine patients (28%) had an increased global LV afterload (􏰁5 mmHg mL/m2). Systemic arterial compliance (P 1⁄4 0.001), circumferential myocardial deformation (P 1⁄4 0.024), and left atrial area index (P 1⁄4 0.04) were independently associated with increased global LV load in multivariable analysis. <br />Conclusion: In asymptomatic patients with severe AS, LV ejection fraction markedly underestimates the extent of myocardial sys- tolic impairment. Intrinsic myocardial dysfunction is particularly common in patients with increased global LV after- load, and especially in the subset of patients with low-flow AS. [less ▲]

Detailed reference viewed: 35 (7 ULg)
Full Text
See detailImpact of glycerol and storage temperature on gluatathione concentration and physiological state of Pseudomonas fluorescens BTP1 freeze-dried
Mputu Kanyinda, Jean-Noël ULg; Pierart, C.; Delvigne, Frank ULg et al

Poster (2012, February 15)

Pseudomonas fluorescens is commonly used as bio-fungicides in agriculture. For this use it requires formulations as either liquid or powder. Formulations have two advantages, storage and transport. Freeze ... [more ▼]

Pseudomonas fluorescens is commonly used as bio-fungicides in agriculture. For this use it requires formulations as either liquid or powder. Formulations have two advantages, storage and transport. Freeze-drying is a commonly used method to preserve bacteria. However, freeze-drying damages the cells, which results in loss of viability. Protective compounds are used to reduce loss of viability during process (freeze-drying and storage). In our study we used flow cytometry analysis to assess the physiological state in which cells are at the end of freeze-drying and Glutathione (GSH) was measured before and during storage. [less ▲]

Detailed reference viewed: 25 (2 ULg)
Full Text
Peer Reviewed
See detailImpact of GODAE products on nested HYCOM simulations of the West Florida Shelf
Halliwell, G. R.; Barth, Alexander ULg; Weiberg, R. H. et al

in Ocean Dynamics (2009), 59(1), 139-155

Nested non-assimilative simulations of the West Florida Shelf for 2004-2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean ... [more ▼]

Nested non-assimilative simulations of the West Florida Shelf for 2004-2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean products. Simulations are nested within an optimum interpolation hindcast of the Atlantic Ocean, the initial test of the US Navy Coupled Ocean Data Assimilation system for the Gulf of Mexico, and a global ocean hindcast that used the latter assimilation system. These simulations are compared to one that is nested in a non-assimilative Gulf of Mexico model to document the importance of assimilation in the outer model. Simulations are evaluated by comparing model results to moored Acoustic Doppler Current Profiler measurements and moored sea surface temperature time series. The choice of outer model has little influence on simulated velocity fluctuations over the inner and middle shelf where fluctuations are dominated by the deterministic wind-driven response. Improvement is documented in the representation of alongshore flow variability over the outer shelf, driven in part by the intrusion of the Loop Current and associated cyclones at the shelf edge near the Dry Tortugas. This improvement was realized in the simulation nested in the global ocean hindcast, the only outer model choice that contained a realistic representation of Loop Current transport associated with basin-scale wind-driven gyre circulation and the Atlantic Meridional Overturning Circulation. For temperature, the non-assimilative outer model had a cold bias in the upper ocean that was substantially corrected in the data-assimilative outer models, leading to improved temperature representation in the simulations nested in the assimilative outer models. [less ▲]

Detailed reference viewed: 23 (10 ULg)
Full Text
Peer Reviewed
See detailImpact of graft-versus-host disease after reduced-intensity conditioning allogeneic stem cell transplantation for acute myeloid leukemia : a report from the Acute Leukemia Working Party of the European group for blood and marrow transplantation
Baron, Frédéric ULg; Labopin, M.; Niederwieser, D. et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (2012), 26(12), 2462-2468

This report investigated the impact of graft-versus-host disease (GVHD) on transplantation outcomes in 1859 acute myeloid leukemia patients given allogeneic peripheral blood stem cells after reduced ... [more ▼]

This report investigated the impact of graft-versus-host disease (GVHD) on transplantation outcomes in 1859 acute myeloid leukemia patients given allogeneic peripheral blood stem cells after reduced-intensity conditioning (RIC allo-SCT). Grade I acute GVHD was associated with a lower risk of relapse (hazards ratio (HR)¼0.7, P¼0.02) translating into a trend for better overall survival (OS; HR¼1.3; P¼0.07). Grade II acute GVHD had no net impact on OS, while grade III–IV acute GVHD was associated with a worse OS (HR¼0.4, Po0.0.001) owing to high risk of nonrelapse mortality (NRM; HR¼5.2, Po0.0001). In time-dependent multivariate Cox analyses, limited chronic GVHD tended to be associated with a lower risk of relapse (HR¼0.72; P¼0.07) translating into a better OS (HR¼1.8; Po0.001), while extensive chronic GVHD was associated with a lower risk of relapse (HR¼0.65; P¼0.02) but also with higher NRM (HR¼3.5; Po0.001) and thus had no net impact on OS. In-vivo T-cell depletion with antithymocyte globulin (ATG) or alemtuzumab was successful at preventing extensive chronic GVHD (Po0.001), but without improving OS for ATG and even with worsening OS for alemtuzumab (HR¼0.65; P¼0.001). These results highlight the role of the immune-mediated graft-versus-leukemia effect in the RIC allo-SCT setting, but also the need for improving the prevention and treatment of severe GVHD. [less ▲]

Detailed reference viewed: 28 (5 ULg)
Full Text
See detailImpact of grazing by amphipods on the dynamics of the epiphytic cover of the Posidonia oceanica leaves : an in vitro experiment.
Michel, Loïc ULg; Gobert, Sylvie ULg; Dauby, Patrick ULg et al

Conference (2010, September 17)

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the epiphytes present on the leaves of the seagrass. However, little or no work has ... [more ▼]

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the epiphytes present on the leaves of the seagrass. However, little or no work has been undertaken to quantify this interaction. Here, we present the results of an in vitro experiment that used seagrass mimics to estimate the impact of grazing by the amphipods Apherusa chiereghinii, Dexamine spiniventris and Gammarus spp on the dynamics of the epiphytic cover. All species reduced epiphyte biomass in a significant way, and grazers preferentially fed on erected algae. Assimilation of epiphyte-derived carbon and nitrogen was monitored using stable isotopes (13C and 15N) labelling, and was obvious in the three taxa. Moreover, grazing activity of amphipods seemed to influence epiphyte physiology, notably by increasing nitrogen uptake by the erected algae. These results shed light on trophic interactions between the amphipods from Posidonia oceanica meadows and the seagrass epiphytic cover, and thus enhance our understanding of the role of these grazers in the functioning of the meadow as an ecosystem. [less ▲]

Detailed reference viewed: 45 (6 ULg)
Full Text
See detailImpact of grazing by amphipods on the epiphytic cover of the Posidonia oceanica leaves: an in situ experiment.
Michel, Loïc ULg; Dupont, Alessandra; Gobert, Sylvie ULg et al

Poster (2010, October 22)

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled ... [more ▼]

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled in vitro conditions, three amphipod taxa (Apherusa chiereghinii,Dexamine spiniventris and Gammarus spp.) are able to drastically deplete the biomass of erected algae, thus influencing the epiphytic cover in both a quantitative and a qualitative way. Here, we tried to assess whether this strong and complex trophic interaction was realized in the field. We designed an in situ experiment that used microcosms placed directly in the meadow, at a depth of 10m, to estimate the impact of grazing by the aforementioned amphipod taxa on the dynamics of the epiphytic cover. Both Gammarus spp. and Dexamine spiniventris caused a significant decrease of the biomass of erected algae and erected animals (bryozoans and hydrozoans). Impact of grazing by Apherusa chiereghinii on these two epiphytic groups was less important, although strong but marginally non-significant (0,1>p>0,05) trends to lower biomasses were present. None of the considered taxa seemed to consume encrusting macro-epiphytes. In addition, assimilation of epiphyte-derived carbon and nitrogen by grazers was monitored using stable isotopes (13C and 15N), and epiphyte elemental content (C & N) was measured. Our results shed light on trophic interactions between the amphipods from Posidonia oceanica meadows and the seagrass epiphytic cover, and thus enhance our understanding of the role of these grazers in the functioning of the meadow as an ecosystem. [less ▲]

Detailed reference viewed: 53 (10 ULg)
Full Text
See detailImpact of grazing on carbon balance of an intensively grazed grassland in Belgium
Jerome, Elisabeth ULg; Beckers, Yves ULg; Beekkerk van Ruth, Jöran ULg et al

Poster (2013, April 09)

This work analyzes the impact of grazing on the carbon balance of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The ... [more ▼]

This work analyzes the impact of grazing on the carbon balance of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The experimental site is a permanent grassland of ca. 4.2 ha located in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). Other studies are conducted at the DTO including measurements of methane (CH4) and nitrous oxide fluxes (Dumortier et al., Geophysical Research Abstracts, Vol. 15, EGU2013-2083-1, 2013; Beekkerk van Ruth et al., Geophysical Research Abstracts, Vol. 15, EGU2013-3211, 2013, respectively). Grassland carbon budget (Net Biome Productivity, NBP) was calculated from Net Ecosystem Exchange (NEE) measured by eddy covariance by taking imports and exports of organic C and losses of carbon as CH4 into account (Soussana et al., 2010). After 2 years of measurements (May 2010 - May 2012), the grassland behaved on average as a CO2 source (NEE = 73 ±31 g C m-2 y-1). After inclusion of all the C inputs and outputs the site was closed to equilibrium (NBP = 23 ±34 g C m-2 y-1). To analyze the impact of grazing on CO2 fluxes, we studied the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration Rd (deduced from the response of daytime fluxes to radiation over 5-day windows). We calculated GPPmax and Rd variation between the end and the beginning of grazing or non-grazing periods (∆GPPmax and ∆Rd, respectively). We observed a significant decrease of GPPmax during grazing periods and measured a ∆GPPmax dependence on the average stocking rate. This allows us to quantify the assimilation reduction due to grass consumption by cattle. On the contrary, no Rd decrease was observed during grazing periods. Moreover, we found that cumulated monthly NEE increased significantly with the average stocking rate. In addition, a confinement experiment was carried out in order to analyze livestock contribution to Total Ecosystem Respiration. Each experiment extended over two days: the first day, cattle was confined in the footprint of the eddy covariance set-up (1.76 ha, 27 LU ha-1) and the second day, it was removed from it. We compared filtered half-hourly data made at 24h intervals, in the presence or absence of cattle, considering that environmental conditions were equivalent (air temperature, wind speed, radiation and wind direction). Results showed that CO2 fluxes were significantly higher when cattle were on the plot. Livestock contribution estimation to CO2 fluxes was on average 6.6 µmol m-2 s-1. [less ▲]

Detailed reference viewed: 69 (15 ULg)
Full Text
See detailImpact of grazing on carbon dioxide flux exchanges in an intensively managed grassland
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2013, September)

To date, there are few studies assessing the impact of specific management events, particularly grazing, on carbon (C) and carbon dioxide (CO2) fluxes in managed grasslands. Grazing effects are indeed ... [more ▼]

To date, there are few studies assessing the impact of specific management events, particularly grazing, on carbon (C) and carbon dioxide (CO2) fluxes in managed grasslands. Grazing effects are indeed difficult to discern. They vary with the stocking rate and the length of the grazing period. Moreover, they are often masked by environmental responses. The aim of the present study was to assess the impact of grazing on the CO2 fluxes of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne Terrestrial Observatory (DTO), located in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). The site is a permanent grassland of ca. 4.2 ha subjected to intensive management. Grassland carbon budget at the system boundaries is calculated from Net Ecosystem Exchange of CO2 measured by eddy covariance by taking imports and exports of organic C and losses of carbon as methane into account. After 2 years of measurements, the site was close to equilibrium. If management practices (harvest, fertilization and imports as supplementary feedings) and climatic conditions had a significant impact on the C balance, the impact of grazing was uncertain, especially on CO2 fluxes. To do this analysis, we distinguished the long term and the short term impacts of grazing on CO2 fluxes. The long term effect results from the biomass consummation by the cattle and from the cattle effluents that modify assimilation and respiration fluxes. This could be quantified only by comparing fluxes before and after grazing periods. The short term impact is due to cattle respiration that is a part of total ecosystem respiration and should be measured in its presence in the field. For the long term effects of grazing on CO2 fluxes, we analyzed the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration normalized at 10°C (Rd,10). Those parameters were deduced from the response of daytime CO2 fluxes to radiation over 5-day windows. We calculated parameters variations between the beginning and the end of grazing and non-grazing periods (∆GPPmax, ∆Rd,10) and analyzed their dependence to stocking rate. We found a significant decreased of ∆GPPmax that allowed us to quantify the assimilation reduction due to grass consumption by cattle. Discrimination of this impact from flux response to climate was possible only after gathering and treating two years of measurements taken under various climatic conditions. At the opposite, no significant evolution of Rd,10 with the average stocking rate was found. The short term impacts were an increase of CO2 fluxes in presence of cattle. It could be distinguished and quantified only thanks to confinement experiments. Each experiment extended over two days: the first day, cattle was confined in the footprint of the eddy covariance set-up (1.76 ha, 27 LU ha-1) and the second day, it was removed from it. We compared filtered half-hourly data made at 24h intervals, in the presence or absence of cattle, considering that environmental conditions were equivalent (air temperature, wind speed, radiation and wind direction). Livestock contribution to CO2 fluxes was estimated to be 2.25 ± 0.68 kg C LU-1 d-1. [less ▲]

Detailed reference viewed: 51 (11 ULg)
Full Text
Peer Reviewed
See detailImpact of Greenland and Antarctic ice sheet interactions on climate sensitivity
Goelzer, H.; Huybrechts, P.; Loutre, M.-F. et al

in Climate Dynamics (2011), 37(5-6), 1005-1018

We use the Earth system model of intermediate complexity LOVECLIM to show the effect of coupling interactive ice sheets on the climate sensitivity of the model on a millennial time scale. We compare the ... [more ▼]

We use the Earth system model of intermediate complexity LOVECLIM to show the effect of coupling interactive ice sheets on the climate sensitivity of the model on a millennial time scale. We compare the response to a 2xCO2 warming scenario between fully coupled model versions including interactive Greenland and Antarctic ice sheet models and model versions with fixed ice sheets. For this purpose an ensemble of different parameter sets have been defined for LOVECLIM, covering a wide range of the model's sensitivity to greenhouse warming, while still simulating the present-day climate and the climate evolution over the last millennium within observational uncertainties. Additional freshwater fluxes from the melting ice sheets have a mitigating effect on the model's temperature response, leading to generally lower climate sensitivities of the fully coupled model versions. The mitigation is effectuated by changes in heat exchange within the ocean and at the sea-air interface, driven by freshening of the surface ocean and amplified by sea-ice-related feedbacks. The strength of the effect depends on the response of the ice sheets to the warming and on the model's climate sensitivity itself. With the ensemble approach in this study we cover a wide range of possible model responses. [less ▲]

Detailed reference viewed: 22 (2 ULg)
Full Text
Peer Reviewed
See detailImpact of growth hormone (GH) deficiency and GH replacement upon thymus function in adult patients.
Morrhaye, Gabriel ULg; Kermani, Hamid; Legros, Jean-Jacques ULg et al

in PLoS ONE (2009), 4(5), 5668

BACKGROUND: Despite age-related adipose involution, T cell generation in the thymus (thymopoiesis) is maintained beyond puberty in adults. In rodents, growth hormone (GH), insulin-like growth factor-1 ... [more ▼]

BACKGROUND: Despite age-related adipose involution, T cell generation in the thymus (thymopoiesis) is maintained beyond puberty in adults. In rodents, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and GH secretagogues reverse age-related changes in thymus cytoarchitecture and increase thymopoiesis. GH administration also enhances thymic mass and function in HIV-infected patients. Until now, thymic function has not been investigated in adult GH deficiency (AGHD). The objective of this clinical study was to evaluate thymic function in AGHD, as well as the repercussion upon thymopoiesis of GH treatment for restoration of GH/IGF-1 physiological levels. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-two patients with documented AGHD were enrolled in this study. The following parameters were measured: plasma IGF-1 concentrations, signal-joint T-cell receptor excision circle (sjTREC) frequency, and sj/beta TREC ratio. Analyses were performed at three time points: firstly on GH treatment at maintenance dose, secondly one month after GH withdrawal, and thirdly one month after GH resumption. After 1-month interruption of GH treatment, both plasma IGF-1 concentrations and sjTREC frequency were decreased (p<0.001). Decreases in IGF-1 and sjTREC levels were correlated (r = 0.61, p<0.01). There was also a decrease in intrathymic T cell proliferation as indicated by the reduced sj/beta TREC ratio (p<0.01). One month after reintroduction of GH treatment, IGF-1 concentration and sjTREC frequency regained a level equivalent to the one before GH withdrawal. The sj/beta TREC ratio also increased with GH resumption, but did not return to the level measured before GH withdrawal. CONCLUSIONS: In patients with AGHD under GH treatment, GH withdrawal decreases thymic T cell output, as well as intrathymic T cell proliferation. These parameters of thymus function are completely or partially restored one month after GH resumption. These data indicate that the functional integrity of the somatotrope GH/IGF-1 axis is important for the maintenance of a normal thymus function in human adults. TRIAL REGISTRATION: ClinicalTrials.gov NTC00601419. [less ▲]

Detailed reference viewed: 153 (29 ULg)
Full Text
See detailImpact of growth rate on the distribution of visually strength-graded West-European Douglas-fir boards
Henin, Jean-Marc; Hebert, Jacques ULg; Jourez, Benoît ULg

Poster (2013, October)

Douglas-fir is a relatively new species within the forest landscape of Wallonia (Southern Belgium). Consequently, some uncertainties remain regarding how to keep full advantage of its high productivity as ... [more ▼]

Douglas-fir is a relatively new species within the forest landscape of Wallonia (Southern Belgium). Consequently, some uncertainties remain regarding how to keep full advantage of its high productivity as well as of the good properties of its wood. Moreover, the recent implementation of the timber strength grading (Council Directive 89/106/EEC) is likely to sensitize forest managers and the sawing industry to the impact of sylviculture on the resource quality. In that context, this research aimed at assessing to what extent the ring width of the trees (RWtree) and the mean girth increment of the stands (MGI) influences, in the frame of a visual strength grading, the distribution of the boards they produce. The experimental material was derived from 33 trees (girth range of between 120cm and 170cm) originating from 11 Douglas-fir stands (age range of between 41 and 69 y.o.) representative of contrasting sylvicultural management practices: RWtree ranged from 3 to 6 mm. From a bolt located 6 to 8.2m height in the standing trees, boards (38X100X2100mm³) were sawn and graded according to the Belgian Standard NBN B 16-520. This research evidenced that: - Only the Knot Area Ratio (KAR) impedes boards to be employed in structural uses. Practically, no board having a KAR allowing S10 grading (S10 corresponds to C30 as defined in EN338) exhibits a ring width higher than 6mm, which is the maximum value accepted for S10 grading (according to NBN B 16-520). These observations demonstrate the highly prevailing character of the knottiness regarding the boards’ grading; - 87% of the boards produced by trees from RWtree≥5mm can be used in structural uses, but only 7% can be classified into S10 strength class. In comparison, trees with RWtree<4.5mm also provided 87% of boards which can be used in structure, but 18% of the boards can be graded into S10 strength class; - 89% of the boards produced by stands with MGI>3cm/year are accepted for structural uses, but only 9% are graded into S10 class. Regarding the stands with MGI≤3cm/year, these values are 89% and 24%, respectively. Growth rate thus doesn’t seem to affect the percentage of Douglas-fir boards fit for structural uses. Dynamic sylviculture however significantly decreases the percentage of boards graded into S10 strength class: although it should be supported by financial assessments, early pruning thus seems highly advisable in a context of dynamic sylviculture. [less ▲]

Detailed reference viewed: 19 (2 ULg)
Full Text
See detailImpact of growth rate on the mechanical properties of Douglas-fir grown in Wallonia (Southern Belgium)
Pollet, Caroline; Henin, Jean-Marc; Jourez, Benoît ULg et al

Poster (2013, October)

Timber is traditionally the main purpose of Douglas-fir in Europe. However, some uncertainties remain concerning the sylviculture that should be applied in order to maximise girth growth rate (GR) without ... [more ▼]

Timber is traditionally the main purpose of Douglas-fir in Europe. However, some uncertainties remain concerning the sylviculture that should be applied in order to maximise girth growth rate (GR) without affecting the good mechanical properties of the wood. So, the present study aimed at assessing to what extent the GR of Douglas-firs grown in Wallonia influences the mechanical properties of wood clear samples. The modulus of elasticity (E) and static bending strength (σf) were measured according to NF B51-016 and NF B51-008 and are discussed according to the ring width measured on the samples, as well as on the growth rate of the trees and of the stands, for both juvenile and mature wood. This assessment will help to provide sylviculture guidelines for foresters. The experimental material was derived from 11 Douglas-fir stands distributed all over Wallonia, Southern Belgium. At the time of felling, the age of the stands ranged from 41 to 69 years old. In each stand, six trees were felled, their girth varying from 120cm to 179 cm. As a consequence of the sampling methodology the growth rate of the trees ranged from 3 mm to 7 mm. From the 66 butt logs, 274 and 884 clear samples were taken in the juvenile and mature wood respectively. This research evidenced that: - Whatever the GR, the mean values of E and σf in the juvenile wood are 20% lower than those in the mature wood; - At the tree level, the mean E and σf of the samples taken from trees with ring width>5mm are about 10% lower than those of the samples taken from trees with ring width<5mm, whether considering juvenile or mature wood; - At the stand level and regardless to the type of wood (juvenile/mature), the mean E and σf of the samples originating from stands with mean girth increment>3cm/year are respectively 5% and 9% lower than those of the samples originating from stands with mean girth increment <3cm/year. This observation should lead the forest manager to consider carefully sylvicultural practices that would induce a too fast juvenile growth; high growth rate in the mature wood do not appear to be a problem considering the properties studied here. One should however take into account the impact of the growth rate on the singularities of the boards. [less ▲]

Detailed reference viewed: 30 (5 ULg)
Full Text
Peer Reviewed
See detailThe impact of HAART initiation on the selection and persistence of HIV-1 CTL-escape mutations
Dilernia, D.A.; Monaco, D.C.; Jones, L.R. et al

in AIDS Research and Human Retroviruses (2010, October), 26(10), 72

The impact of HAART initiation on the selection and persistence of HIV-1 CTL-escape mutations D.A. Dilernia,1 D.C. Monaco,1 L.R. Jones,2 G.D. Damilano,1 S. Rodriguez,3 H. Salomon1 1Argentinean Reference ... [more ▼]

The impact of HAART initiation on the selection and persistence of HIV-1 CTL-escape mutations D.A. Dilernia,1 D.C. Monaco,1 L.R. Jones,2 G.D. Damilano,1 S. Rodriguez,3 H. Salomon1 1Argentinean Reference Center for AIDS, Capital Federal, Argentina; 2División de Biología Molecular, Estación de Fotobiología, Playa Unión, Rawson, Chubut, Argentina; 3INTA, Castelar, Buenos Aires, Argentina Background: Immune response drives the selection of CTL escape mutations during the course of HIV infection. After initiation of HAART, antiviral drugs exert a strong selective force leading to an important limitation of viral replication. Our objective was to evaluate the impact of HAART initiation on the selection and persistence of CTL-escape mutations. Methods: Blood samples were collected from 113 newly HIV diagnosed individuals. A second sample was collected from 49 of them after 3 years. (12 of which were still drug-naı¨ve in the second sample). Dynamics of CTL-escape mutations identified in the gag gene by statistical analysis of HLA genes and viral sequences, including multiple comparison corrections (BH method) and phylogeny correction (Bayesian MCM method), were analyzed. Epitope-specific immune response was evaluated by ELISPOT against sequence-based designed peptides. Results: Immune response was evaluated on 113 individuals on an HLA-allele basis. Positive responses were detected against 6 of the 9 epitopes containing HLA-associated CTL-escape mutations.A03-restricted epitope RLRPGGKKK had the highest frequency of detection in allele-matched individuals (75%). Epitopes harboring the CTL-escape mutations identified through negative associations (i.e. escape is consensus) had lower frequency of detection: A02-restricted SLYNTVATL(25%) and A24-resctricted KYKLKHIVW(0%). Epitope sequences analysis over the second sample of 21 patients successfully sequenced showed that 38% of them did not have evidence of escape neither in the first sample nor in the second, 44% had the escape mutations in both samples and in 18%the escape mutations appeared in the second sample. Of the 7 individuals containing the epitopes of the last group, only 2 had initiated HAART (28.6%) while 64.3% (9/14) of individuals where no escape emerged, had initiated HAART. Conclusion: Accumulation of CTL-escape mutations at the population-level impaired recognition by individuals studied while initiation of HAART may prevent the selection of new escape mutations even in advanced stages of infection. [less ▲]

Detailed reference viewed: 87 (0 ULg)
Full Text
Peer Reviewed
See detailImpact of Harmonia axyridis (Coleoptera: Coccinellidae) on the survival rates of other aphidophagous species in semi-field conditions
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

in Communications in Agricultural and Applied Biological Sciences (2011, May 24), 76(2), 219-226

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild ... [more ▼]

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild predator, consuming other aphid natural enemies. Interactions between this exotic ladybird and other aphidophagous species present in Belgian agro-ecosystems such as Coccinella septempunctata, Episyrphus balteatus and Chrysoperla carnea are asymmetric to the benefit of H. axyridis. This study focuses on the survival rate of three aphidophagous species Harmonia axyridis (Ha), Coccinella septempunctata (C7) and Episyrphus balteatus (Eb) placed in cages in biological fields of potato and sugar beet. During June and July, hermetic cages were disposed on the crops with 10 larvae (second stage) of each aphidophagous. Four types of cages were observed (1) Ha+Eb+C7+ aphids, (2) Ha+Eb+C7, (3) Eb+C7+ aphids and (4) Eb+C7. Each combination was repeated three times. In sugar beet fields, E. balteatus was the species with the highest mortality rate. The two coccinellid species had a better survival rate than E. balteatus. All aphidophagous species had higher mortality rates in absence of aphids. In potato, when aphids were present in excess, the survival rates of all aphidophagous insects were lower than in sugar beet probably because A. fabae is less adapted to the potato morphology. Nevertheless, we have observed in potato no mortality of C. 7-punctata during all its development cycle. This suggests that (1) C. 7-punctata may use aphids as food sources more efficiently than H. axyridis and (2) that interactions between aphidophagous could be less frequent (difficulty of mobility). In potato and sugar beet, H. axyridis had the longest development cycle, being still at the larval stage when C. 7-punctata and E. balteatus reached the pupae stage. We can suppose that pupae of E. balteatus and C. 7-punctata were an alternative food (intraguild prey) to H. axyridis when aphids were lacking. Pupae are immobile and therefore more sensitive to the attack of predators. [less ▲]

Detailed reference viewed: 87 (28 ULg)
Full Text
Peer Reviewed
See detailImpact of health professionals utilization induced by musculoskeletal disorders among active subjects
Rabenda, Véronique ULg; Manette, Christelle; Lemmens, Régine et al

in Osteoporosis International (2005, March), 16(Suppl.3), 110

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailIMPACT OF HEAVY METALS ON PHYSIOLOGICAL AND PROTEOMIC RESPONSES OF WILLOWS (SALIX SP.)
Evlard, Aricia ULg; Sergeant, Kjell; Ferrandis, Salvador et al

Poster (2012)

In 2010, around 3,800 sites in Wallonia (Belgium) were identified as potentially contaminated by heavy metals, a result of their past industrial and agricultural activities [1]. The technique of using ... [more ▼]

In 2010, around 3,800 sites in Wallonia (Belgium) were identified as potentially contaminated by heavy metals, a result of their past industrial and agricultural activities [1]. The technique of using plants to remediate contaminated sites (phytoremediation) has been studied for over twenty years. In particular, the use of trees (alder, willow, poplar) has been considered because of their large biomass production [2] [3] [4] [5]. The aim of this study was to identify the potential of local willow ecotypes to grow in the presence of heavy metals using lysimeters filled with dredging sludge. Several willow ecotypes were compared realizing morphological and physiological measurements (chlorophyll fluorescence, electrolyte leakage, carbohydrate content). The plant responses to metal stress were also investigated using a proteomic approach. Heavy metals contents in leaves and stems were analysed. With this study, the potential of these trees to valorise contaminated, abandoned sites in Belgium was evaluated. [1] Cellule Etat de l'environnement wallon (2010). Tableau de bord de l'environnement wallon. SPW-DGARNE-DEMNA-DEE. [2] Dickinson N. M. (2000). Strategies for sustainable woodland on contaminated soils. Chemosphere 41(1-2): 259-263. [3] Meers E., Lamsal S., Vervaeke P., Hopgood M., Lust N. and Tack F. M. G. (2005). Availability of heavy metals for uptake by Salix viminalis on a moderately contaminated dredged sediment disposal site. Environ Pollut 137(2): 354-364. [4] Meers E., Vandecasteele B., Ruttens A., Vangronsveld J. and Tack F. M. G. (2007). Potential of five willow species (Salix spp.) for phytoextraction of heavy metals. Environ Exp Bot 60(1): 57-68. [5] Rosselli W., Keller C. and Boschi K. (2003). Phytoextraction capacity of trees growing on a metal contaminated soil. Plant Soil 256(2): 265-272. [less ▲]

Detailed reference viewed: 53 (6 ULg)
Full Text
Peer Reviewed
See detailImpact of helium diffusion and helium-flash-induced carbon production on gravity-mode pulsations in subdwarf B stars
Hu, Haili; Nelemans, G.; Aerts, C. et al

in Astronomy and Astrophysics (2009), 508

Context: Realistic stellar models are essential to the forward modelling approach in asteroseismology. For practicality however, certain model assumptions are also required. For example, in the case of ... [more ▼]

Context: Realistic stellar models are essential to the forward modelling approach in asteroseismology. For practicality however, certain model assumptions are also required. For example, in the case of subdwarf B stars, one usually starts with zero-age horizontal branch structures without following the progenitor evolution. <BR /> Aims: We analyse the effects of common assumptions in subdwarf B models on the g-mode pulsational properties. We investigate if and how the pulsation periods are affected by the H-profile in the core-envelope transition zone. Furthermore, the effects of C-production and convective mixing during the core helium flash are evaluated. Finally, we reanalyse the effects of stellar opacities on the mode excitation in subdwarf B stars.<BR /> Methods: We computed detailed stellar evolutionary models of subdwarf B stars, and their non-adiabatic pulsational properties. Atomic diffusion of H and He is included consistently during the evolution calculations. The number fractions of Fe and Ni are gradually increased by up to a factor of 10 around log T = 5.3. This is necessary for mode excitation and to approximate the resulting effects of radiative levitation. We performed a pulsational stability analysis on a grid of subdwarf B models constructed with OPAL and OP opacities.<BR /> Results: We find that helium settling causes a shift in the theoretical blue edge of the g-mode instability domain to higher effective temperatures. This results in a closer match to the observed instability strip of long-period sdB pulsators, particularly for l â ¤ 3 modes. We show further that the g-mode spectrum is extremely sensitive to the H-profile in the core-envelope transition zone. If atomic diffusion is efficient, details of the initial shape of the profile become less important in the course of evolution. Diffusion broadens the chemical gradients, and results in less effective mode trapping and different pulsation periods. Furthermore, we report on the possible consequences of the He-flash for the g-modes. The outer edge of a flash-induced convective region introduces an additional chemical transition in the stellar models, and the corresponding spike in the Brünt-Väisälä frequency produces a complicated mode trapping signature in the period spacings. <BR /> [less ▲]

Detailed reference viewed: 18 (3 ULg)
Full Text
Peer Reviewed
See detailImpact of hemodynamic load on exercise capacity in aortic stenosis
Dulgheru, Raluca Elena ULg; Magne, Julien ULg; Capoulade, R et al

in International Journal of Cardiology (2013)

Detailed reference viewed: 86 (6 ULg)