Last 7 days
Bookmark and Share    
Full Text
See detailFreeplay-induced limit cycle oscillation mitigation using linear and nonlinear tuned vibration absorbers
Verstraelen, Edouard ULg; Kerschen, Gaëtan ULg; Dimitriadis, Grigorios ULg

in Proceeding of the IFASD 2017 Conference (2017, July)

Structural nonlinearities such as freeplay in control surface bearings and actuators or in connections between wings and external payloads sometimes lead to aeroelastic limit cycle oscillations at ... [more ▼]

Structural nonlinearities such as freeplay in control surface bearings and actuators or in connections between wings and external payloads sometimes lead to aeroelastic limit cycle oscillations at airspeeds lower than the linear flutter speed of the aircraft. In parallel, numerous studies demonstrated the potential of linear and nonlinear tuned vibration absorbers to increase the flutter speed of linear and continuously hardening aeroelastic systems such as two-degree- of-freedom wings or long span bridges. In this work, the effect of linear and nonlinear tuned vibration absorbers is studied on a wing with pitch plunge and control surface deflection degrees of freedom and with freeplay in pitch. Depending on the tuning of the linear absorber, the linear flutter speed of the system can be increased by 10% or the onset of limit cycle oscillations due to the freeplay can be delayed by 7.7% and their amplitude can be significantly decreased. The addition of cubic hardening forces on the absorber can further decrease the limit cycle amplitude in a limited airspeed range at the cost of an increase in limit cycle amplitude in another airspeed range. Conversely, the addition of a freeplay hardening force on the absorber can decrease the limit cycle amplitude without any detrimental effect. [less ▲]

Detailed reference viewed: 24 (4 ULg)
Full Text
See detailThe grammaticalization of Russian taxonomic nouns
Kolyaseva, Alena ULg

Conference (2017, July)

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailSpecular sets
Berthé, Valérie; De Felice, Clelia; Delecroix, Vincent et al

in Theoretical Computer Science (2017), 684

Detailed reference viewed: 16 (2 ULg)
Full Text
Peer Reviewed
See detailcopycat: Testing Differential Treatment of New Transport Protocols in the Wild
Edeline, Korian ULg; Kühlewind, Mirja; Trammell, Brian et al

in Applied Networking Research Workshop (2017, July)

Recent years have seen the development of multiple transport solutions to address the ossification of TCP in the Internet, and to ease transport-layer extensibility and deployability. Recent approaches ... [more ▼]

Recent years have seen the development of multiple transport solutions to address the ossification of TCP in the Internet, and to ease transport-layer extensibility and deployability. Recent approaches, such as PLUS and Google's QUIC, introduce an upper transport layer atop UDP; their deployment therefore relies on UDP not being disadvantaged with respect to TCP by the Internet. This paper introduces copycat, a generic transport protocol testing tool that highlights differential treatment by the path in terms of connectivity and QoS between TCP and a non-TCP transport protocol. copycat generates TCP-shaped traffic with custom headers, and compares its performance in terms of loss and delay with TCP. We present a proof-of-concept case study (UDP vs. TCP) in order to answer questions about the deployability of current transport evolution approaches, and demonstrate the extent of copycat's capabilities and possible applications. While the vast majority of UDP impairments are found to be access-network linked, and subtle impairment is rare, middleboxes might adapt to new protocols that would then perform differently in the wild compared to early deployments or controlled environment testing. [less ▲]

Detailed reference viewed: 19 (3 ULg)
Full Text
Peer Reviewed
See detailWEATHERING ON THE DEVONIAN SLATES AND CHARACTERIZATION OF A BENTONITE LAYER IN THE WESTERWALD (GERMANY)
Fontaine, François ULg; Hamaekers, Helen; Hoffmann, Andreas et al

Conference (2017, July)

The Westerwald region is one of the largest and oldest clay mining areas of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of ... [more ▼]

The Westerwald region is one of the largest and oldest clay mining areas of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The two main goals of this study are first to improve the knowledge on the weathering processes of the Devonian slates that led to the current setting of those clay deposits by studying the mineralogical and chemical composition of the clays with depth. The second goal is to characterize a bentonite layer underneath the Miocene basalt cover using quantitative X-ray diffraction, chemical analysis, BET, cation exchange capacity and scanning electron microscope. A 20 meter deep quarry mining the Devonian bedrock in southern Westerwald has been sampled on its entire depth. The XRD results show no significant variations of the mineralogy with depth, except for the phyllosilicates. The minerals of the < 2 μm fraction are illite, kaolinite, smectite and mixed-layers minerals (vermiculite-chlorite and illite-chlorite). The proportions of the minerals in the mixed-layers chlorite-vermiculite vary with depth. At the bottom of the quarry, the proportion of vermiculite is very low while in the top, the proportion of vermiculite is higher. This is explained by the degree of the weathering, logically more intense at the top of the quarry. Trace elements compositions are currently being investigated. A 3 meter thick greenish to brownish bentonite layer has been found in the eastern part of the Westerwald region. The XRD performed on different samples of this bentonite shows a relatively heterogeneous composition: montmorillonite (60-80%), kaolinite (5-12%), illite (0-7%), goethite (2-15%), talc (0-10%), K-feldspars (0-7%), plagioclase (0-4%) and traces of amphibole and pyroxene. This bentonite is probably the result of the weathering of volcanic ashes. Since there are not many outcrops of this bentonite layer, its spatial distribution is studied by drilling. [less ▲]

Detailed reference viewed: 23 (2 ULg)
Full Text
See detailStable isotopes reveal effects of environmental changes on ecological niches of Iphimediidae amphipods
Michel, Loïc ULg; d'Udekem d'Acoz, Cédric; Frederich, Bruno ULg et al

Poster (2017, July)

When faced with environmental changes, organisms are expected to have some intrinsic ability to adapt through ecological plasticity. However, this process is still poorly understood in many Antarctic ... [more ▼]

When faced with environmental changes, organisms are expected to have some intrinsic ability to adapt through ecological plasticity. However, this process is still poorly understood in many Antarctic invertebrates. Here, we focused on Iphimediidae amphipods, as this widely distributed family shows important ecological diversity. In total, 248 amphipods (19 species) from two widely different zones (the West Antarctic Peninsula, or WAP, and Adélie Land, AL) were studied to elucidate how environment can influence ecological niche parameters. Ecological niches were explored using stable isotope ratios of carbon and nitrogen and the SIBER approach (Jackson et al., 2011). The isotopic niche of the whole amphipod assemblage was wider in WAP than in AL. This was true for both total (proxy of the whole range of resources exploited by animals) and the core (proxy of the most commonly used resources) isotopic niches. The ratio between total and core isotopic niches was smaller in WAP than in AL (4.13 vs. 5.74), suggesting that in WAP, animals commonly use a greater relative percentage of the resources to which they have access. Niche modelling at the specific level revealed that this trend was not found in all taxa. For example, niches of Gnathiphimedia sexdentata and Iphimediella microdentata were bigger in WAP than in AL, following the general pattern. On the other hand, niches of Echiniphimedia echinata and E. hodgsoni had the same width in both areas. Moreover, relative niche overlap between these two species was much higher in WAP (42%) than in AL (20%). Our results indicate that the widely different environmental conditions encountered by the animals in these two zones clearly influence their ecology. Overall, Iphimediidae amphipods tend to exploit more resources in WAP, i.e. in the zone where impacts of global change (temperature increase, sea ice cover decrease) are the strongest. Niche overlap between some closely related (i.e. congeneric) species was also more important in WAP. Ultimately, environmental changes in this region might reinforce these trends, which might lead to competition and perturb amphipod community structure. This research was funded by the Belgian Federal Science Policy Office (BELSPO) in the framework of the vERSO and RECTO projects. [less ▲]

Detailed reference viewed: 6 (2 ULg)
Peer Reviewed
See detailThe role of Gender, Race, and Class in Transnational Political Movements: Mexican and Colombian Women Engaging in Homeland Politics from Europe’s Capital
Lara-Guerrero, Larisa; Vivas Romero, Maria ULg

Conference (2017, June 30)

Drug trafficking is a mounting security problem in Latin America, specifically for the primary producers of narcotics in the region: Mexico and Colombia. The security concern from both countries has ... [more ▼]

Drug trafficking is a mounting security problem in Latin America, specifically for the primary producers of narcotics in the region: Mexico and Colombia. The security concern from both countries has triggered the political and social mobilization of Mexican and Colombian migrants from abroad many of them from the Global City of Brussels. This paper unpacks the motivations and dynamics behind transnational political activism organized by Mexican and Colombian women living in Brussels. By integrating and revising insights from social movements theories, political transnationalism from migration studies and intersectionality studies, this paper elaborates on the role of migrant women organizing and sustaining transnational political movements to change the political conditions of their countries of origin. The ethnographic evidence presented in this paper reveals the importance to recognize the individual level in the analysis of transnational movements. Women are cognitive actors with political ideals and emotions whose political activism is highly influenced by social categorizations such as gender, race, class, and generation. [less ▲]

Detailed reference viewed: 16 (2 ULg)
Full Text
See detailPlant traits variability within and among populations in the context of calcareous grassland restoration
Harzé, Mélanie ULg

Doctoral thesis (2017)

In Western Europe, abandonment of traditional forms of agriculture has caused the fragmentation of semi-natural grasslands, affecting ecosystems functioning as well as population survival. Habitat ... [more ▼]

In Western Europe, abandonment of traditional forms of agriculture has caused the fragmentation of semi-natural grasslands, affecting ecosystems functioning as well as population survival. Habitat restoration has become a crucial aspect of grasslands conservation, and one of the main issues is evaluating restoration success and setting appropriate criteria to do so. Indicators used to judge whether a restoration has been successful may concern a wide range of organisms. They may be defined at different geographical scales and may concern various levels of biodiversity organization. Among them, population parameters are less represented despite their usefulness. To consider restoration as a success, restored populations of targeted species should demonstrably possess characteristics allowing their dispersal, reproduction, growth and adaptation to the environment. In this thesis, the use of plant population parameters for evaluating grassland restoration was assessed based on a literature review. Then, the success of calcareous grassland restoration was determined regarding colonization of restored grasslands by five calcareous grasslands species; Helianthemum nummularium, Hippocrepis comosa, Potentilla tabernaemontani, Sanguisorba minor and Scabiosa columbaria. Population establishment and intra-specific functional trait variability in response to the environment were observed and compared among restored and reference populations of those species, through field inventories and in-situ traits measurements in calcareous grasslands of south Belgium. Moreover, a glasshouse experiment was set-up with the aim to evaluate the intra-specific variability in response to drought stress in reference populations of P. tabernaemontani. The results indicated that population parameters were less well studied for evaluating grassland restoration success compared to indicators related to ecosystems and communities. The population parameters used to assess the success of calcareous grassland restoration showed that the study species colonized restored sites and established new populations. The fitness of the restored populations was very high. High intra-specific trait variability was highlighted at a very local scale in the reference habitat. Individuals exhibited high leaf dry matter content (LDMC), low specific leaf area (SLA) and low vegetative height in relation to low soil depth and high potential incident radiation (PDIR). These environmental variables are possibly linked to the availability of soil moisture. Further, the relationship between traits and environmental variables was not always consistent in restored sites. However, the intra-specific variability of plant traits was similar in the reference and restored grasslands. Finally, the findings from the glasshouse experiment suggested that individuals originating from drier parts of calcareous grasslands better survive drought stress.   The overall conclusion of this thesis is rather optimistic concerning restored populations of the five specialist plant species studied, specifically regarding their colonization, persistence and response to the environment or to potential climate change. The conclusions must, however, be modified depending on the reference ecosystem used as a model. This approach has to be integrated into a multi-scales and a multi-species approach to fully evaluate restoration outputs. Yet, this thesis has contributed to the understanding of population responsiveness to habitat restoration, as well as to the evaluation of restoration success of calcareous grasslands in Belgium. [less ▲]

Detailed reference viewed: 9 (1 ULg)
Peer Reviewed
See detailThe art to talk on immigration: a state of emergency
Da Silva, Amanda Carolina ULg

Conference (2017, June 29)

This paper intend to present the results of the state of emergency project. The project started in 2014 with a simple question: how researchers that work in immigration can communicate with civil society ... [more ▼]

This paper intend to present the results of the state of emergency project. The project started in 2014 with a simple question: how researchers that work in immigration can communicate with civil society outside the traditional academic channels? It is not only a matter of popularization of academic research, but mainly brings researchers into society, far from the academic walls. The answer to this question was the art and the spaces of culture. Art, and also cultural spaces have enormous potential, its could bring together different social groups and help researchers to be in society, and making their research accessible. In the society, debates on immigration are mostly dominated by media and political representations, what is also polarizing societies between solidarity and anti-immigration movement's. Therefore, the presence of researchers to discuss the immigration issue in society has become urgent. The state of emergency project had as a bases my research, “The borders of Nord-Pas-deCalais” (2014), and brought together two dancers, two acrobats, a scene director and a plastic artist. The project started from the assumption that art is a collective production, but artistic intention started with the individual consciousness on the issue the artist is focusing. It was adopted the artistic improvisation method to develop a spectacle and other tolls. In order to incorporate research on immigration into artistic production it was necessary to present and to appropriate the artists of basic concepts, but also carry out a fieldwork, that was developed during a month at the French border (Calais city). The methodology adopted by the artists consisted in a fieldwork. The project took two years to be concluded. The result was a dance spectacle, “Dites a ma mère que je suis la”, and a hybrid form of workshop that mixes the artistic and the methods of immigration research. I contrast, I developed during the project a multi-sited ethnography whit the artists. Where the main objective was to understand which impact the scientific knowledge on the issue could produce in artist's way to see immigration, and how this new approach could change the researcher and artist productions. [less ▲]

Detailed reference viewed: 15 (0 ULg)
Peer Reviewed
See detailCo-producing sociotechnical solutions in difficult times: the art of governing nuclear wastes in France
Parotte, Céline ULg; Delvenne, Pierre ULg

Conference (2017, June 29)

Radioactive wastes and their management are posing pressing political and epistemic issues to modern societies such as, for instance, how shall we design sociotechnical solutions to deal with an object ... [more ▼]

Radioactive wastes and their management are posing pressing political and epistemic issues to modern societies such as, for instance, how shall we design sociotechnical solutions to deal with an object with a half-life of more than 100.000 years? This paper’s starting point is the so-called “participatory turn” in the nuclear waste management (NWM) in France, when tensions appeared concerning claims of epistemic authority of national nuclear agencies. In 1990, in the aftermath of violent contestations and citizen mobilization in four Departments, the then Prime Minister of France, Michel Rocard, decided to impose a one-year moratorium on the research conducted by the national nuclear waste management organization (ANDRA). A not so well-known parliamentary technology assessment (PTA) institution, OPECST (the French Office Parlementaire d’Evaluation des Choix Scientifiques et Technologiques), was called to the rescue to clear up a difficult situation and to restore trust between state and scientific agencies and a critical population. We find that OPECST played a surprisingly central role in defining the French NWM program. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Full Text
See detailQUALITY IMPROVEMENT OF POTATO STEAMED BREAD USING FOOD HYDROCOLLOIDS
Liu, Xingli ULg

Doctoral thesis (2017)

Nowadays, there is an increasing interest for composite or gluten-free products due to some economic, nutritional reasons or the number of the celiac patient. The estimated prevalence of Celiac disease is ... [more ▼]

Nowadays, there is an increasing interest for composite or gluten-free products due to some economic, nutritional reasons or the number of the celiac patient. The estimated prevalence of Celiac disease is about 1% of the general population, and it affects persons of any age, race, and ethnic group. Steamed bread is a traditional staple food of China, and has been consumed for at least 2000 years, taking up almost 40% of wheat consumption, and the popularity is increasing around the world. However, most traditional wheat steamed bread lack essential nutrients, including lysine, dietary fiber, vitamins, and minerals, etc. Therefore, the use of composite flour for steamed bread making has attracted great attention. Potato (Solanum tuberosum) is one of the most widely planted vegetables worldwide and is the only tuber used as a major food crop. Potato has a balanced amino acid composition, high total vitamin and mineral levels, and also contains phytochemicals such as polyphenols, polyamines, and carotenoids. However, the replacement of wheat flour is a major challenge for food technologist to produce the steamed bread with desirable quality and technological properties because that gluten is important to retain gas to obtain the desired volume and texture in a dough system. It is essential to form a strong protein network required for the desired viscoelasticity, and the easiest way to ensure the viscoelasticity properties is via the use of food hydrocolloids. Therefore, the aim of this work was to study the quality improvement of potato steamed bread using food hydrocolloids. Firstly, the influence of potato flour on dough rheological properties and quality of steamed bread showed that the dough stability and specific volume of steamed bread were significantly decreased with the potato flour proportions increasing. Then we carried out the comparative study of the nutritional quality of steamed and baked breads from four potato cultivars because that the steamed and baked breads were two type of staple food in eastern and western countries, respectively. The results showed that potato flour addition increased the contents of dietary fiber, potassium, vitamin C, and total polyphenol contents and antioxidant activity. Hongmei was the optimum choose of the studied four cultivars, followed by Blue Congo, Shepody, and Atlantic, in terms of nutritional value. For the same cultivar, the nutritional value of steamed bread was higher than that of baked bread. Secondly, the effect of different food hydrocolloids on the dough rheology and steamed bread quality parameters in composite and gluten-free formulations based on potato flour was studied. Compared to control, the food hydrocolloids addition significantly increased tightly bound water population, water absorption, starch gelatinization temperature, dough viscoelasticity, recovery percentage and development height. Little adhesion and aggregation of starch were observed and the density of potato protein bands was decreased when food hydrocolloids were added, suggesting that some aggregation formed between starch-hydrocolloids or proteins-hydrocolloids. Moreover, steamed breads with food hydrocolloids presented higher specific volume, lower hardness, and lower estimated glycemic index. In conclusion, food hydrocolloids showed the potential as a gluten replacement in composite or gluten-free potato steamed bread, particularly HPMC. Thirdly, we optimized the formulations of gluten-free potato steamed bread. The optimal gluten-free steamed bread could be produced by adding 4.84 g/100g pregelatinized potato flour (PGPF), 1.68 g/100g hydroxypropylmethylcellulose (HPMC), 5.87 g/100g egg white protein (EWP) and 69.69 g/100g water based on potato flour, and this optimal bread was compatible with regular wheat bread in key sensory properties. Moreover, the optimized solid phase microextraction parameters (sample weight 2.42 g, extraction time 60 min, and extraction temperature 50°C) were adopted to determine the volatile compounds of gluten-free potato steamed bread. 72 volatile compounds were detected in the dough and crumb. The contents of alcohols, acids and esters increased significantly with the fermentation time increasing, which would improve the aroma of steamed bread. However, further investigations are needed to elucidate the underlying mechanisms of action and the interactions with dough components and making additives. The other studies should be focused on technological approaches to improve steamed bread quality, which involved different flour particles, high pressure technology and application of sourdough. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Peer Reviewed
See detailMean and variance of Dynamic Functional Connectivity in Parkinson’s Disease
Baquero Duarte, Katherine Andrea ULg; Guldenmund, Pieter; Rouillard, Maud ULg et al

Poster (2017, June 29)

Detailed reference viewed: 12 (3 ULg)
Peer Reviewed
See detail"Exploring Experiences of Inequality in European Urban Centers: Towards an Intersectional and Transnational Approach."
Vivas Romero, Maria ULg; Ramos, Cristina

Conference (2017, June 28)

What strategies do migrants living in European cities use to challenge inequalities in access to healthcare, participation in the labor market and the creation of social support networks? The papers in ... [more ▼]

What strategies do migrants living in European cities use to challenge inequalities in access to healthcare, participation in the labor market and the creation of social support networks? The papers in this panel aim to respond to this question by drawing from transnational and intersectional approaches conceptualizing inequalities as sets of relationships between people and broader structures in which interactions generate better opportunity for some more than for others (Tilly, 2000). Panel participants consider that these interactions and the benefits that can be obtained through migration are affected by various social categories such as gender, class, sexual identity, transnational connections, and citizenship. Intersectional approaches allow to examine how these axes of inequality (Crenshaw, 1989; Anthias, 2001) simultaneously affect migration outcomes and also how they operate differently according to the geographical space in which they develop: origin and host societies as well as transnationally. Nonetheless, the papers presented in this panel will also emphasize migrants’ agency to resist or conform to the inequalities they face. Overall, this panel aims to contribute to the study of migration and inequality at the conceptual and methodological levels. At the theoretical level, the panel will build on new debates on the reproduction of intersectional inequalities in transnational settings (Faist, 2016, Amelina, 2017). At the methodological level, all paper presenters have use multi-sited ethnographic methods (working in cities such as Madrid, London, Milan, Brussels and Frankfurt) and will therefore use the panel as an opportunity to discuss the strengths and weaknesses of such method. [less ▲]

Detailed reference viewed: 45 (2 ULg)
See detailFrom internal experts to external interlocutors? EU agencies and procedures assessing the equivalence of third country legal rules with EU regulatory standards
Van Cleynenbreugel, Pieter ULg

Scientific conference (2017, June 28)

this paper will offer an overview of procedures allowing EU agencies to determine the equivalence of third country regulatory regimes and conceptualise the accountability challenges they pose. Proceeding ... [more ▼]

this paper will offer an overview of procedures allowing EU agencies to determine the equivalence of third country regulatory regimes and conceptualise the accountability challenges they pose. Proceeding in three parts, the first part will identify and classify the different third country equivalence procedures in place. Analysing the legal basis for agency intervention and the specific powers granted to the respective agencies in that respect, this part will allow to develop a topology of two different equivalence roles conferred on EU agencies. Building upon this descriptive analysis, the second part will identify two accountability challenges associated with each of the identified third country equivalence procedure categories. Seeking to overcome those challenges, the third part of the paper will make four pointed suggestions aimed at recognising explicitly and in a more centralised way the external action powers conferred on EU agencies. Doing so would at the very least allow better to tailor modifications to the external action frameworks against the background of which existing equivalence procedures currently already implicitly operate. [less ▲]

Detailed reference viewed: 10 (0 ULg)
Full Text
See detailThe behavior of pesticide during beer brewing and the toxicity of pesticide using state-of-the-art omic tools
Kong, Zhiqiang ULg

Doctoral thesis (2017)

Beer is an extremely popular beverage worldwide, representing the third-most popular drink after water and tea. And barley is the major raw material used for beer production. However, various combinations ... [more ▼]

Beer is an extremely popular beverage worldwide, representing the third-most popular drink after water and tea. And barley is the major raw material used for beer production. However, various combinations of pesticides are widely used at several stages of barley culti¬vation and during post-harvest storage to control pest and fungal disease. Hence, traces of these pesticides might remain in the beer produced from the treated ingredients. Hence, monitoring trace levels of pesticide residues during beer brewing and investigated the effects of pesticide residue on the quality of beer is essential. First, the behavior and fate of 3 pesticides (triadimefon, malathion, and dichlorvos) and the main metabolites (triadimenol and malaoxon) during barley storage or beer processing were assessed using a pilot-plant equipment. The residues of all products were determined using liquid chromatography coupled with tandem mass spectrometry. Field investigation of the dissipation rate kinetics for triadimefon and malathion during storage indicated that their half-life was twice as high when 5 times the recommended dosage was used. Milling had little effect on removing dichlorvos and malathion residues, whereas they were substantially removed when the spent grains were mashed. The calculated processing factors after processing were all <1, indicating that the residual ratios of dichlorvos and malathion were reduced during the entire process. In conclusion, storage and processing extensively reduced pesticide residue levels in barley and beer; however, greater focus needs to be paid to the toxicity of their metabolites in commercial by-products. Then we selected the triadimefon as the target fungicide to further study its behavior, the dissipation kinetics of TF during fermentation mediated by two different yeast strains, Saccharomyces cerevisiae IAPPST 1401 (Y1) and CICC 1202 (Y2), and found that Y2 promoted the degradation of TF. Response surface methodology was used to optimize fermentation process variables, in order to achieve the maximum removal rate of TF and the minimum production of its corresponding metabolite, triadimenol (TN). Triadimefon is also a widely used triazole fungicide with one chiral carbon center, Stereoselective degradation of triadimefon was found during barley storage, the half-life of S-(+)-triadimefon was 36.5d, 31.5d and 30.1d, while R-(-)-traidmefon was 69.3d, 53.3d and 33d under 4°C, 25°C and 40°C, respectively. During brewing process, both enantiomers of triadimefon were easily degraded. After fermentation, little triadimefon detected in the beer, while RS-(+) and SS-(-)-triadimenol were detectable. This research provides accurate information for evaluating the risk of food safety. Furthermore, we investigated the effect of triadimefon affect the quality and flavor of the fermented beer, The effect of triadimefon on yeast growth and the sensory quality of beer were studied. There were significant differences in sensory quality between beer samples fermented with and without triadimefon based on data obtained with an electronic tongue and nose. Such an effect was most likely underlain by changes in yeast fermentation activity, including decreased utilization of maltotriose and most amino acids, reduced production of isobutyl and isoamyl alcohols, and increased ethyl acetate content in the fungicide treated samples. Furthermore, yeast metabolic profiling by phenotype microarray and UPLC/TOF-MS showed that triadimefon caused significant changes in the metabolism of glutathione, phenylalanine and sphingolipids, and in sterol biosynthesis. Thus, triadimefon negatively affects beer sensory qualities by influencing the metabolic activity of S. cerevisiae during fermentation, emphasizing the necessity of stricter control over fungicide residues in brewing by the food industry. [less ▲]

Detailed reference viewed: 25 (1 ULg)
Full Text
See detailSpatial diversification of agroecosystems towards biological control of insect pests: A focus on intercropping and wildflower strips
Hatt, Séverin ULg

Doctoral thesis (2017)

Facing the limits of input-intensive agriculture, agroecology aims at thinking ways to design a sustainable agriculture that is economically viable and socially relevant. It notably invites to mobilize ... [more ▼]

Facing the limits of input-intensive agriculture, agroecology aims at thinking ways to design a sustainable agriculture that is economically viable and socially relevant. It notably invites to mobilize ecological processes within agroecosystems in order to enhance the delivery of ecosystem services towards reducing the use of external inputs – among others insecticides. For enhancing biological control of insect pests, a strategy is to spatially diversify agroecosystems at the field scale. Whereas increasing plant diversity could directly negatively affect pest development on the one hand (i.e. bottom-up effect), providing flowering features could allow the enhancement of natural enemies and their direct effect on pest populations on the other hand (i.e. top-down effect). The present thesis focused on intercropping (i.e. the cultivation of at least two crop species simultaneously in a same field) as a way to diversify crop habitat, and the sowing of wildflower strips as a non-crop feature. A systematic analysis of the literature revealed that, in most of studies, wheat (Triticum aestivum L.)-based intercropping allows a reduction of insect pests on crops, without necessarily favouring their natural enemies, compared to pure-stands. Besides, the provision of flowering resources, by for instance sowing wildflower strips, can attract and support flower visiting predators and parasitoids. Hence, in a first set of field experiments, combining the two tactics of increasing crop diversity and providing flowering resources was tested. First in China, wheat crop was associated with oilseed rape (Brassica napus L.), but it neither allowed reducing aphid (Hemiptera: Aphididae) abundance nor enhancing their natural enemies compared to pure stands. Instead, aphid density – independently from the treatments – affected natural enemy abundance, and interspecific relations between aphids and their natural enemies were observed. Second in Belgium, wildflower strips were sown within a wheat field, which led to a reduction of aphid density in wheat plots in between flowering features and an increase of aphidophagous hoverflies (Diptera: Syrphidae) compared to pure-stand wheat. Nevertheless, the presence of flowering strips did not affect the other natural enemies, i.e. lacewings (Neuroptera: Chrysopidae), ladybeetles (Coleoptera: Coccinellidae) and parasitoid wasps (Hymenoptera: Braconidae). Therefore, a second set of field experiments focussed on ways to compose mixtures of wild flowers attractive to a diversity of natural enemies. Flower functional traits were considered due to their effect on insect behaviour. First, the hypothesis that mixtures with high functional diversity attract and support a high abundance and diversity of aphid flower visiting predators was tested. This hypothesis was not verified. Instead, the high density in the plots of some flower species (especially the Asteraceae Leucanthemum vulgare Lam.) known to be attractive to flower visitors was supposed to have overwhelmed the effect of functional diversity. Second, a methodology was developed to identify which flower traits significantly affect natural enemy abundance – in this experiment parasitoids of oilseed rape beetle pests (i.e. Meligethes spp. [Coleoptera: Nitidulidae] and Ceutorhynchus spp. [Coleoptera: Curculionidae]) – in flower mixtures. Among seven traits, visual traits (i.e. colour, ultra-violet reflectance) and the one related to food availability (i.e. corolla morphology) were found to significantly affect parasitoid abundance. These results highlight that (i) increasing plant diversity at the field scale can – but not systematically – favour a reduction of insect pests, (ii) including flowering features can enhance some – but not all – of their natural enemies, and (iii) in order to compose flower mixes attractive to natural enemies, specific flower traits – rather than functional diversity at the mixture level – can be considered. These results are discussed in a broader perspective. Indeed, strategies to spatially diversify crop and non-crop habitats in agroecosystems are various, as well as the ways to compose, manage and design such habitats. Also, processes at larger scales than the field may be determinant. Moreover, insects are not the only pests, and pests are not the only biotic or abiotic elements that need to be regulated in agroecosystems. Controlling multiple pests simultaneously but also enhancing the provision of multiple regulating services represent challenges for future research in agriculture. [less ▲]

Detailed reference viewed: 26 (4 ULg)
Full Text
See detailCrop water productivity of winter wheat at multi-scale and its improvements over the Huang-Huai-Hai Plain, China
Liu, Qin ULg

Doctoral thesis (2017)

Droughts and water shortage are generally accepted to be one of the most critical problems faced by worldwide agriculture, and it is so especially in China where agricultural production and prosperity are ... [more ▼]

Droughts and water shortage are generally accepted to be one of the most critical problems faced by worldwide agriculture, and it is so especially in China where agricultural production and prosperity are largely dependent on the timely, adequate and proper distribution of rainfall. The analysis of water productivity is becoming very critical in light of population growth, food security and increasing pressure on water resources. However, there is limited understanding of the spatio-temporal variation of crop water productivity (CWP) from the rotation system and its key influencing factors in Huang-Huai-Hai Plain (3H Plain) in which there is an over-exploitation of groundwater region and where future warmer and drought conditions will intensify crop water demand. As the largest water user, agricultural sector is facing a challenge to produce more crops with less water. Consequently, 3H Plain faced the double threat of both making contributions of high and stable yield to government and improving CWP of winter wheat through reducing water consumption. The overall ambition of this thesis was to investigate to what extent the grain yield and crop water productivity for winter wheat can respond to climate change and drought across the 3H Plain. In our study, a combined dataset composed of a historical 54-year time series and the RCP 8.5 scenario from 40 meteorological stations was provided by the China Meteorological Administration. Among these 40 stations we selected 12 stations with more detailed information available. The minimal data sets required for model operation include daily climatic variables, soil information and management information collected from the China Soil Scientific Database. Finally, we also used satellite data to estimate water productivity mainly involved in MODIS products including MOD11A1 (land surface temperature/surface emissivity), MOD13A2 (NDVI) and MCD43B3 (surface albedo). We used SPEI-PM method, DSSAT-CERES-Wheat model and SEBAL model to explore the characteristics in grain yield and crop water productivity for winter wheat in response to climate change and drought associated with their improvements across the 3H Plain. Our work demonstrated the investigation that an increase of ET0 was predicted leading to subsequent drought rise in frequency, duration, severity and intensity under the RCP 8.5 scenario. The cumulative probability of the simulated yield reduction was detected to be higher during jointing to heading stage in northern than southern region due to water stress and changes in the management inputs. The lower CWP was mainly situated in the low plain-hydropenia irrigable land and dry land (zone2) and the hill-wet hot paddy field (zone6), which suggests that it is an important issue and opportunity for improving agricultural water management in the water-scarce 3H Plain. The spatial increase of yield principally controlled increase of water productivity in north agricultural sub-regions and the spatial increase of water productivity was more governed by increment of yield than the reduction of ETa in other agricultural sub-regions. It will be adopted to develop feasible straw mulching, regulated deficit irrigation, and soil water storage and preservation to reduce pressure on groundwater over-exploitation, especially for winter wheat in the 3H Plain. In our work, major agronomic consequences have been drawn regarding the reform of the common agricultural policy in Huang-Huai-Hai Plain, China. Researchers are encouraged to further investigations into how to implement these practices with emphasis of improving the sustainability of these agro-ecosystems. [less ▲]

Detailed reference viewed: 18 (3 ULg)
See detailRôle des lymphocytes T TCR γδ dans la progression des lésions associées à l'infection par les papillomavirus humains
Van Hede, Dorien ULg

Doctoral thesis (2017)

Cervical cancer was the fourth most frequent cancer in women in 2012, with the majority of cases occurring in less developed countries. Although this cancer is induced by Human Papillomavirus (HPV ... [more ▼]

Cervical cancer was the fourth most frequent cancer in women in 2012, with the majority of cases occurring in less developed countries. Although this cancer is induced by Human Papillomavirus (HPV) infections that have a high prevalence, only a very few percentage of infected women will developed this disease. Host immune defenses are essential to clear infection and to kill virus-infected transformed cells. Indeed, majority of infected women clear the virus within two years while immunocompromised patients are more likely to develop cervical preneoplastic lesions and cancers. γδ T cells have been shown to protect against the formation of squamous cell carcinoma (SCC) in several models. Nowadays, the contribution of γδ T cells in HPV associated uterine cervical SCC is unknown. Here we investigated the impact of γδ T cells in a transgenic mouse model of carcinogenesis induced by HPV16-oncoproteins. Surprisingly, γδ T cells promoted the development of HPV16-oncoprotein-induced lesions. These oncoproteins induced a decrease in epidermal Skint-1 expression and modification of the associated anti-tumor Vγ5+ γδ T cells (or DETC), which were joined by other γδ T cell subsets actively producing IL-17. Consistent with a proangiogenic role, γδ T cells promoted the formation of blood vessels in the dermis underlying the HPV-induced lesions. In human cervical, IL-17+ γδ T cells could be only observed at the cancer stage (SCC) (but not in less advanced cervical lesions), where HPV oncoproteins are highly expressed, supporting the clinical relevance of our observations in mice. Overall, our results suggest that HPV16-oncoproteins induce a reorganization of the local epithelial-associated γδ T cell Subpopulations thereby promoting angiogenesis and cancer development. [less ▲]