Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailDenitrification, anaerobic ammonium oxidation, and dissimilatory nitrate reduction to ammonium in an East African Great Lake (Lake Kivu)
Roland, Fleur ULg; Darchambeau, François; Borges, Alberto ULg et al

in Limnology and Oceanography (2017)

We investigated anaerobic nitrogen (N) cycling in the water column of Lake Kivu, a deep meromictic tropical lake in East Africa. Data were collected at one station in the Northern Basin and one in the ... [more ▼]

We investigated anaerobic nitrogen (N) cycling in the water column of Lake Kivu, a deep meromictic tropical lake in East Africa. Data were collected at one station in the Northern Basin and one in the Southern Basin, during two sampling campaigns (June 2011—dry season, and February 2012—rainy season). Short-term incubations of sulfide-free water with 15N-labeled substrates revealed high potential denitrification and dissimilatory nitrate reduction to ammonium (DNRA) rates (up to 350 and 36 nmol N produced L−1 h−1, respectively), while anaerobic ammonium oxidation (anammox) was lower (up to 3.3 nmol N produced L−1 h−1). However, anammox rates were 15 nmol N produced L−1 h−1 when 15 NH4+ was added at depths where NH4+ concentrations were very low (< 1 μmol L−1). With the addition of 5 μmol L−1 of 15 NO3− and 10 μmol L−1 of H2S, denitrification and anammox were stimulated in the Northern Basin, while the increase of DNRA rates was less notable. In the Southern Basin, the addition of H2S decreased denitrification rates, probably because of competition with DNRA, which increased, while no effect was observed on anammox. This study puts into evidence the co-occurrence of denitrification, anammox and DNRA, for the first time in a great tropical lake, and underlines the spatial heterogeneity of these processes. Contrary to numerous reports in literature, we show that anammox can significantly occur in presence of H2S, suggesting that the contribution of anammox in the N cycle may be underestimated. [less ▲]

Full Text
Peer Reviewed
See detailClostridium difficile in beef cattle farms, farmers and their environment: assessing the spread of the bacterium
Rodriguez Diaz, Cristina ULg

in Veterinary Microbiology (2017)

n recent years, several studies have described the presence of Clostridium difficile in healthy and diarrhoeic farm and domestic animals. In pigs and cattle, the isolation of some PCR-ribotypes associated ... [more ▼]

n recent years, several studies have described the presence of Clostridium difficile in healthy and diarrhoeic farm and domestic animals. In pigs and cattle, the isolation of some PCR-ribotypes associated with human infection, especially PCR-ribotypes 014 and 078, has led us to hypothesize about the zoonotic transmission of C. difficile infections. If these animals are reservoirs of C. difficile, farmers in close contact with their animals are particularly at risk of acquiring and spreading the bacterium. This study investigates the presence of C. difficile in closely associated populations, beef cattle and farmers, as well as in the animal feed, manure and dust in five different farms in Belgium. C. difficile was isolated from calves and cattle with a prevalence varying between 5.5% and 11.3%. Furthermore, all of the isolates were toxigenic. An important age and breed effect was observed in the colonization of C. difficile. For age, there was a higher probability of colonization in calves of less than 6 months in age than in cattle over 11 months of age. For the type of breed a higher prevalence of the bacterium was detected in the Limousin breed than in the Belgian Bleu breed. By contrast, none of the human and animal feed samples tested positive for C. difficile. The results obtained indicate a persistent animal reservoir of C. difficile, but an indirect dissemination to humans, probably via the environment. [less ▲]

Full Text
Peer Reviewed
See detailHow classroom teachers do take the ‘Physical Activity Pauses at School’ (PAPS)? A project implemented in Wallonia
Cloes, Marc ULg; Cloes, Stéphanie

Conference (2017, September 15)

In Wallonia, special efforts are needed in order to respect the international recommendations on physical activity in youth. School is definitely considered as a central pillar in the promotion of an ... [more ▼]

In Wallonia, special efforts are needed in order to respect the international recommendations on physical activity in youth. School is definitely considered as a central pillar in the promotion of an active lifestyle. The aim of this study was to analyze the implementation process of daily activity breaks called ‘Physical Activity Pause at School’ (PAPS) in 6 primary schools of the Liege area. 23 classroom teachers were involved. They had to propose at least one PAPS/day during the 15-16 school year. Diary, questionnaires, focus groups and interviews were used for data collecting. Two thirds of the subjects continued until the end. The videos were not systematically used. Four teachers’ profiles were identified: Innovators, Invested, Careful, and Disengaged. 12 factors facilitating or limitating the involvement of the teachers have been analyzed. The study comes to a model of concrete actions to respect in order to increase the chances of success in the implementation of such project. [less ▲]

Detailed reference viewed: 19 (0 ULg)
Full Text
See detailEnvironmental sustainability of the Walloon cereal sector using Life Cycle Assessment (LCA) fed with local data - Current situation and potential evolution scenarios
Van Stappen, Florence ULg

Doctoral thesis (2017)

In a world facing a growing population and diminishing resources, agriculture has a major role to play in terms of sustainable provision of food and feed, job creation in rural areas, preservation of ... [more ▼]

In a world facing a growing population and diminishing resources, agriculture has a major role to play in terms of sustainable provision of food and feed, job creation in rural areas, preservation of natural resources and climate change mitigation. As a very intensive agricultural region, Wallonia (southern Belgium) dedicates more than half of its arable land to cereal crops. Thanks to a long history of research and development, rich soils and favorable climate conditions, yields of cereals such as wheat or barley cropped in Wallonia are amongst the highest in the world. As a major sector in the Walloon agricultural landscape, the cereal sector therefore calls for production and processing opportunities that meet the requirements for sustainable agriculture. In this context, the objectives of the present thesis were to evaluate the environmental sustainability of current and potential evolution scenarios for the Walloon cereal sector using the Life Cycle Assessment (LCA) methodology fed with local data. On the basis of current uses of cereals grown in Wallonia, this research aimed first at describing various scenarios for the future of the Walloon cereal sector. Based on contrasting hypotheses, four scenarios for the uses of Walloon cereals by 2030 were defined with the support of stakeholders involved in all parts of the sector. Issues such as competition between food uses (both direct and indirect) and non-food uses or Walloon dependency on cereal imports were addressed in these scenarios, which illustrate contrasting future situations, from food self-sufficiency to drastic globalization, through the development of new outlets combining changes in crop-growing practices and consumption habits and new technologies. Using the widely used, yet continuously improved, methodology of LCA, the second part of this work evaluated the environmental impacts of cereal production in Wallonia. It identified the production steps with the greatest contribution to environmental impacts. The leading contributor was mineral fertilizer production, for which this work used up-to-date data from best available technologies and demonstrated the importance of using such recent data. The second greatest contributor to environmental impacts was emissions from mineral and organic fertilizer use on field, before and during plant growth until harvest. As well as being very important, these emissions are also extremely variable, depending on agricultural practices, soil and weather conditions, and thus particularly difficult to assess. This is particularly true of nitrogen- and carbon-related emissions, whose dynamics are very problematic to evaluate. This work demonstrated the limits of commonly used emission models, which use generic emission factors and therefore weaken LCA results. As a result, the use of more specific models, based on field trials and adapted to local conditions, was placed at the top of the list for future research in this area. From a methodological point of view, this part of the work also confirmed the influence of the functional unit used to express LCA results. It showed the strong link between yield and environmental impacts, and identified cereal crops demonstrating efficient input management, with lower impacts per kilogram of product, per hectare and per euro. Other methodological choices, such as the choice of allocation factor between grain and straw, also showed their relevance. In short, this part of the work demonstrated the pertinence of using local data to feed LCAs of agricultural productions and identified the most sensitive parameters to be adjusted in priority to achieve good quality LCAs. Thirdly, on the basis of an original methodology comparing equivalent balanced animal diets, a case study on cereal processing in a biogas plant assessed the consequences of diverting feedstock from the animal feed industry into the bioenergy sector. Despite the environmental benefits brought by fossil fuel displacement and digestate use as organic fertilizer, the replacement of raw materials previously used as animal feed induces additional impacts potentially more important than the benefits of this technology. The key message from this finding is that it is urgent to stop using potentially edible raw material for bioenergy production. The only countervailing consideration here is that current trends towards decreasing meat consumption would in the longer term make lands and raw material available for purposes other than animal feed. The strength of all the LCA results in this work was tested using a wide range of sensitivity and uncertainty analyses. These good practices, often neglected due to time constraints, proved to be essential to be able to draw robust conclusions. Through the application of LCA to the Walloon cereal sector, this work had some practical implications for enhancing the quality of LCAs of agricultural productions. It showed the sensitivity of the method to the use of local data and demonstrated the strengths and limitations of the method. It has produced specific LCA references for cereal production in Wallonia, which are useful for feeding environmental impact assessments of cereal-based products sourced with Walloon cereal crops. Further improvements could include the use of specific models to assess on-field emissions from fertilizer use and the consideration of additional impact indicators regarding soil organic stock changes, biodiversity impacts and water consumption. Additionally, assessing impacts at the rotation scale would reflect more accurately the way farmers optimize their crops and allow for the evaluation of more diverse cropping systems. [less ▲]

Detailed reference viewed: 22 (1 ULg)
Full Text
See detailOf trees and men: new insights into man-environment relationships in the moist forests of central Africa during the late Holocene
Morin, Julie ULg

Doctoral thesis (2017)

In central Africa, vegetation history has been documented by paleoenvironmental studies (especially palynology), which mainly concerned the way climate has shaped the forest landscapes. Human impacts in ... [more ▼]

In central Africa, vegetation history has been documented by paleoenvironmental studies (especially palynology), which mainly concerned the way climate has shaped the forest landscapes. Human impacts in this region have hardly been studied so far, especially at local scale. The main objective of this PhD is to propose an approach based on archaeology and the use of charred botanical remains found in soils, either wood charcoal or seeds, in order to document the Holocene anthropogenic impacts on the forest structure and composition. When coupled with the diachronic analysis of human activities, these land-use biomarkers can allow a better understanding of the relationship between man and his environment in central Africa during this period. Thereby, the first part of this PhD introduces the conceptual framework and the materials and methods used during the research. Then, the second part constitutes the core of the work, and presents the chronology of human activities in the northern Congo Basin, the use of biomarkers to discrimate between these activities, either domestic or agricultural, and the effect of the recent anthropogenic activities in the dynamic of several light-demanding tree populations. Finally, the third part draws the main recommendations of the work, and formulates potential for additional research. [less ▲]

Detailed reference viewed: 38 (7 ULg)
Full Text
See detailRuralité et mondialisation dans l'oeuvre de Josef Winkler
Neelsen, Sarah ULg

Conference (2017, September 15)

Une œuvre à ce point enracinée dans le paysage, la culture et la langue de l’Autriche semblait peu propice à intégrer les bouleversements de l’ordre mondial après 1989 et son auteur bel et bien enfermé ... [more ▼]

Une œuvre à ce point enracinée dans le paysage, la culture et la langue de l’Autriche semblait peu propice à intégrer les bouleversements de l’ordre mondial après 1989 et son auteur bel et bien enfermé dans une certaine tradition nationale. Pourtant à partir de 1996, les récits de voyage, journaux intimes et romans sur l'Inde se multiplient. La mondialisation semble donc bien avoir eu un impact profond sur son travail et l'étude approfondie du roman Roppongi montre comment se construisent des effets de résonance entre rituels funéraires hindous et catholiques. Cette communication analyse les différences entre interculturalité et mondialisation, lieux et non-lieux et conclut sur la tension entre la mobilité des corps et l'obsession de l'image fixe. [less ▲]

Full Text
See detailPhysics at the Ultra-high Energies
Bhattacharya, Atri ULg

Scientific conference (2017, September 15)

Full Text
See detailThe Einstein Telescope
Cudell, Jean-René ULg

Speech/Talk (2017)

Brief description of the Einstein Telescope project.

Full Text
See detailDark matter
Laletin, Maxim ULg

Scientific conference (2017, September 15)

Full Text
Peer Reviewed
See detailSharing good practices in physical education to promote physical activity, wellness and health
Bonni, Jérémy ULg; Cloes, Marc ULg

Poster (2017, September 15)

The Wallonia-Brussels Federation is about to overhaul its education system, which will directly affect teacher training. Under the “Pact for Excellence in Education”, a group of experts – the Consortium ... [more ▼]

The Wallonia-Brussels Federation is about to overhaul its education system, which will directly affect teacher training. Under the “Pact for Excellence in Education”, a group of experts – the Consortium “Physical Activities, Well-Being and Health” – drawn from the 12 French-speaking institutions training PE teachers (universities and colleges) has been mandated by the Ministry of Education to design devices and tools aiming at implementing the new common core curriculum that is under construction. Good practices have been identified then described in information sheets common to the different consortiums of the PEE and listed in a table that cross-references the 6 dimensions of physical activity at school (Snyers et al., 2014) and the 20 objects of teaching-learning in health education (Turcotte et al., 2011). These good practices are meant to be shared later within a community of practice. This paper provides a description of one of these information sheets in order to illustrate the methodology applied in this project. [less ▲]

Full Text
See detailCoronagraphy and Interferometry: Imaging the sky at high contrast and high-angular resolution
Defrere, Denis ULg; Absil, Olivier ULg

Scientific conference (2017, September 15)

Short overview of the main activities related to exoplanet imaging at the STAR Institute

Full Text
See detailPresentation of thermo-mechanical laboratory of CSL
Plesseria, Jean-Yves ULg

Scientific conference (2017, September 15)

Presentation of the Thermo-machanical group of CSL

Full Text
See detailExoplanetary Transits
Gillon, Michaël ULg

Scientific conference (2017, September 15)

Exoplanetary Transits

Full Text
See detailPresentation of CSL's Laboratory of Electronics at the First STAR Workshop on 15/09/2017
Graas, Estelle ULg

Scientific conference (2017, September 15)

Presentation of CSL's Laboratory of Electronics at the First STAR Workshop on 15/09/2017

Full Text
See detailQuasars and Gravitational lenses in STAR: Selected highlights
Sluse, Dominique ULg

Scientific conference (2017, September 15)

Quasars and Gravitational Lenses in STAR: Selected highlights

Full Text
See detailDesign, assembly and test of a near-infrared spectrograph for the TIGRE telescope
Kintziger, Christian ULg

Scientific conference (2017, September 15)

The presentation introduces the different major steps of the design of a near-infrared spectrograph that will be installed at the TIGRE telescope, Mexico.