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See detailIs going to space still worthwhile?
Rochus, Pierre ULiege

Conference (2017, June 27)

Very often, we hear: “Is it still worth going to space? Aren’t there better causes to spend our money on, here on Earth?” At this talk, Pierre Rochus will highlight the importance of the benefits that ... [more ▼]

Very often, we hear: “Is it still worth going to space? Aren’t there better causes to spend our money on, here on Earth?” At this talk, Pierre Rochus will highlight the importance of the benefits that space activities and space research bring. He will try to convince the credulous that besides those everyday space applications that we obviously can no longer do without (GPS, for instance!), space science activities are also essential for humanity. Space research not only gives answers to fundamental questions facing humanity but the technical design of future missions also poses a challenge to the collective imagination. Space scientific research is not only an intellectual challenge, it is much more: it is a stimulus for technical developments; it requires constant, leading-edge developments in different technical domains such as:  systems miniaturisation,  light detectors,  new materials,  coatings,  cryogenics,  mechanisms,  electrical motors,  tribology (the study of friction, wear, lubrication, and the design of bearings)  ... Space Research gives rise to spin-offs and unpredictable developments which will come in useful in our future daily life. One hope is that some part of the huge budgets dedicated to military research could be transferred to space activities. And, of course, it is very important to convince young people to study sciences and technology - where better to start, than in space? [less ▲]

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See detailAtmospheric free acidity from cloud processing
Franco, Bruno ULiege; Taraborrelli, Domenico; Gromov, Sergey et al

Conference (2017, June 27)

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See detailCharacterizing the leaching of sperrylite (PtAs2) in cyanide-based solutions
Mwase Malumbo, James ULiege; Petersen, Jochen

in Hydrometallurgy (2017)

The mineral sperrylite (PtAs2), unlike other Pt minerals, has shown to be resistant to cyanide leaching, even at elevated temperatures of 50 °C. This has prevented further development of a two-stage heap ... [more ▼]

The mineral sperrylite (PtAs2), unlike other Pt minerals, has shown to be resistant to cyanide leaching, even at elevated temperatures of 50 °C. This has prevented further development of a two-stage heap leaching process, of which the second stage is cyanide leaching for a Platreef ore, due to a considerable portion of the Pt being present as sperrylite. Through a comprehensive set of leaching tests, this study has shown that sperrylite leaches slowly in cyanide due to eventual passivation. The addition of ferricyanide to the cyanide solution results in significantly more Pt being leached (up to 16 times) than with cyanide only under identical process conditions. However, over time passivation occurred in this system also, but can be seemingly be overcome by filtering, rinsing and re-suspending the sperrylite. This was further investigated using a reactor system continuously fed with a ferricyanide-cyanide to leach a fixed bed of sperrylite mineral. Again, gradual passivation of the mineral phase was observed, which was fully reversible following a day of feeding with distilled water. XPS analysis of fresh and leached mineral indicated a depletion of As on the mineral surface, which tallied with an observed preferential leaching of As during leaching, at least initially. As a result, it is postulated that a less cyanide-soluble compound of the form PtAs(X) forms, where x is < 2. The ease with which the leaching process can be restarted after rinsing the mineral indicates that the adsorption of solution species is the key step in forming a passivating layer. This adsorption is potentially favoured by the gradual surface transformation. Finally, an electrochemical study confirmed that the ferricyanide-cyanide system facilitated an electron transfer reaction at the sperrylite surface with the likely oxidation of As and reduction of the ferricyanide. Gradual passivation of the surface was also observed in this system. [less ▲]

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See detailChine-Costa Rica. La projection des normes chinoises en Amérique centrale
Wintgens, Sophie ULiege

Conference (2017, June 27)

Cet article a pour hypothèse que l’accroissement des échanges économiques et commerciaux de la Chine avec le Costa Rica, premier pays membre du Système d’intégration centraméricain (SICA) à avoir signé un ... [more ▼]

Cet article a pour hypothèse que l’accroissement des échanges économiques et commerciaux de la Chine avec le Costa Rica, premier pays membre du Système d’intégration centraméricain (SICA) à avoir signé un accord de libre-échange avec Pékin, va de pair avec la projection des normes économiques et politiques chinoises en Amérique centrale. Afin de démontrer cette hypothèse, il article analyse les enjeux de la présence de la Chine au Costa Rica afin de voir si sa politique commerciale envers l’Amérique centrale est porteuse d’un projet économico-politique régional. [less ▲]

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See detailCrop water productivity of winter wheat at multi-scale and its improvements over the Huang-Huai-Hai Plain, China
Liu, Qin ULiege

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 ▲]

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See detailLimit cycle oscillations of cantilever rectangular flat plates in a wind tunnel
Giannelis, Nicholas; Vio, Gareth A.; Dimitriadis, Grigorios ULiege

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2017 (2017, June 27)

A closed form state-space model of the nonlinear aeroelastic response of thin cantilevered flat plates is derived using a combination of Von Karman thin plate theory and a linearized continuous time ... [more ▼]

A closed form state-space model of the nonlinear aeroelastic response of thin cantilevered flat plates is derived using a combination of Von Karman thin plate theory and a linearized continuous time vortex lattice aerodynamic model. The modal-based model is solved for the amplitude and period of the limit cycles of the flat plates using numerical continuation. The resulting predictions are compared to experimental data obtained from identical flat plates in the wind tunnel. It is shown that the aeroelastic model predicts the linear flutter conditions and nonlinear response of the plates with reasonable accuracy, although the predicted limit cycle amplitude variation with airspeed is different to the one measured experimentally due to unmodelled physics. [less ▲]

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See detailDynamic stall onset variation with reduced frequency for three stall mechanisms
Boutet, Johan ULiege; Dimitriadis, Grigorios ULiege; Amandolese, Xavier

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2017 (2017, June 27)

A set of unsteady aerodynamic load measurement is performed on three oscillating airfoils with distinct stall mechanisms: a flat plate, a NACA0012, and a NACA0018. The airfoils are forced to oscillate in ... [more ▼]

A set of unsteady aerodynamic load measurement is performed on three oscillating airfoils with distinct stall mechanisms: a flat plate, a NACA0012, and a NACA0018. The airfoils are forced to oscillate in pitch around the stall angle of attack with prescribed frequency and amplitude. A criterion proposed by Sheng et al. is used to locate the onset of the flow separation process associated with dynamic stall, and quantify its variation with an equivalent reduced pitch rate. The validity of this criterion is tested for the three airfoils at low Reynolds number, Re = 2 × 10^4. Results are compared with the experimental data obtained by Sheng et al. at higher Reynolds number of Re = 1.5 × 10^6. [less ▲]

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See detailResearch on Fast Aeroelastic Modeling Methods for the Transonic Regime
Güner, Hüseyin ULiege; Dimitriadis, Grigorios ULiege; Terrapon, Vincent ULiege

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2017 (2017, June 27)

Two methods for modeling unsteady transonic flows at low computational cost are presented as a first step towards a fast and accurate aeroelastic calculation methodology for the preliminary design stage ... [more ▼]

Two methods for modeling unsteady transonic flows at low computational cost are presented as a first step towards a fast and accurate aeroelastic calculation methodology for the preliminary design stage in the transonic flow regime. The first approach corresponds to a quasi-steady approximation based on few steady simulations that is improved through the use of an unsteady filter. The second approach is based on the interpolation of dynamic modes between solutions at different frequencies that are obtained either from Dynamic Mode Decomposition (DMD) of unsteady simulations or directly from Harmonic Balance (HB) simulations. The two methods are illustrated in the case of a pitching airfoil in the transonic regime. Results show that the first method is fast and provides a first approximation of the unsteady dynamics. The computational cost of the second approach is higher, but the method provides better results in predicting aerodynamic forces and shock motion for a large range of reduced frequencies. [less ▲]

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See detailFreeplay-induced limit cycle oscillation mitigation using linear and nonlinear tuned vibration absorbers
Verstraelen, Edouard ULiege; Kerschen, Gaëtan ULiege; Dimitriadis, Grigorios ULiege

in Proceeding of the IFASD 2017 Conference (2017, June 27)

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 ▲]

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See detailMUNIX vs TASPM
BENMOUNA, Karim ULiege; MILANTS, Christophe ULiege; WANG, François-Charles ULiege

Poster (2017, June 27)

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See detailLes finances publiques belges: aperçu et commentaire
Piron, Damien ULiege

Conference given outside the academic context (2017)

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See detailEmergency Medical Services: When Fatigue Becomes The Norm.
Berastegui, Pierre ULiege; Jaspar, Mathieu ULiege; GHUYSEN, Alexandre ULiege

Conference (2017, June 27)

BACKROUND: Emergency Medical Services (EMS) routinely work at the very limit of their capacity due to growing emergency rooms visits and residents’ shortage. In this context, EMS workers are regularly ... [more ▼]

BACKROUND: Emergency Medical Services (EMS) routinely work at the very limit of their capacity due to growing emergency rooms visits and residents’ shortage. In this context, EMS workers are regularly asked to work more than 10 hours a day, on varying shifts and with short recuperation breaks. Two approaches can be used to reduce fatigue-related risk: reducing the likelihood a fatigued operator is working (i.e. fatigue reduction), or reducing the likelihood a fatigued operator will make an error (i.e. fatigue proofing). In Emergency Medical Services, formal risk control mainly focuses on reduction strategies such as reducing work hours while proofing strategies develops as an implicit element of the safety system. OBJECTIVE: Our purpose is to identify individual proofing and reduction strategies used by emergency residents and to investigate how they relate to fatigue, performance and patient safety indicators. METHODS: First, we conducted 4 focus-group sessions with a total of 25 EMS residents to elicit perceived consequences of fatigue and strategies used to cope with them. Focus group results were used to design a questionnaire assessing how often EMS residents personally used any of the strategies reported during sessions. Second, we administered the questionnaire to a larger sample and conducted a prospective observational study with a repeated within-subjects component. A total of 45 EMS residents participated in the study for a total of 400 shifts analyzed. We gathered sleep diaries, subjective sleepiness, reaction time, self-reported medical errors and performance ratings at different time point during both day and night shift using an android-based application. Sleep time and activity levels were confirmed using wrist actigraphy. DISCUSSION: We will discuss what can be drawn from our results in terms of individual and collective resilience processes with a focus on the potential for implementation of more formal processes at a system level.  [less ▲]

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See detailLocal Governments Expenditures and Spillover Effects - Evidence from Walloon Municipalities
Starck, Vincent ULiege; Denomerenge, Jonathan ULiege

Speech/Talk (2017)

Presentation of preliminary results about local governments expenditures analysis and quantification of spillover effects in Wallonia.

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See detailDeformation measurements by ESPI of the surface of a heated mirror and comparison with numerical model
Languy, Fabian ULiege; Vandenrijt, Jean-François ULiege; Saint-Georges, Philippe et al

in Proceedings of SPIE (2017, June 26), 103291M

The manufacture of mirrors for space application is expensive and the requirements on the optical performance increase over years. To achieve higher performance, larger mirrors are manufactured but the ... [more ▼]

The manufacture of mirrors for space application is expensive and the requirements on the optical performance increase over years. To achieve higher performance, larger mirrors are manufactured but the larger the mirror the higher the sensitivity to temperature variation and therefore the higher the degradation of optical performances. To avoid the use of an expensive thermal regulation, we need to develop tools able to predict how optics behaves with thermal constraints. This paper presents the comparison between experimental surface mirror deformation and theoretical results from a multiphysics model. The local displacements of the mirror surface have been measured with the use of electronic speckle pattern interferometry (ESPI) and the deformation itself has been calculated by subtracting the rigid body motion. After validation of the mechanical model, experimental and numerical wave front errors are compared. [less ▲]

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See detailNF-kB-dependent regulation of TET1 in breast cancers
Canale, Annalisa ULiege; Collignon, Evelyne; Al Wardi, Clémence et al

Poster (2017, June 26)

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See detailPharmacokinetic characterization of [18F]UCB-H PET radiopharmaceutical in the rat brain.
Becker, Guillaume ULiege; Warnier, Corentin; Serrano Navacerrada, Maria Elisa ULiege et al

in Molecular Pharmaceutics (2017), 14(8), 2719-2725

The synaptic vesicle glycoprotein 2A (SV2A), a protein essential to the proper nervous system function, is found in presynaptic vesicles. Thus, SV2A targeting, using dedicated radiotracers combined with ... [more ▼]

The synaptic vesicle glycoprotein 2A (SV2A), a protein essential to the proper nervous system function, is found in presynaptic vesicles. Thus, SV2A targeting, using dedicated radiotracers combined with positron emission tomography (PET), allows the assessment of synaptic density in the living brain. The first-in-class fluorinated SV2A specific radioligand, [18F]UCB-H, is now available at high-activity through an efficient radiosynthesis compliant with the current good manufacturing practices (cGMP). We report here a non-invasive method to quantify [18F]UCB-H binding in rat brain with microPET. Validation study in rats confirmed the need of high enantiomeric purity to target SV2A in vivo. We demonstrated the reliability of a population-based input function to quantify SV2A in preclinical microPET setting. Finally, we investigated the in vivo metabolism of [18F]UCB-H and confirmed the negligible amount of radiometabolites in the rat brain. Hence, the in vivo quantification of SV2A using [18F]UCB-H microPET seems a promising tool for the assessment of the synaptic density in the rat brain, and opens the way for longitudinal follow-up in neurodegenerative diseases rodents’ models. [less ▲]

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See detailEvidence of activation of vagal afferents by non-invasive vagus nerve stimulation: An electrophysiological study in healthy volunteers
NONIS, Romain ULiege; D'Ostilio, Kevin; SCHOENEN, Jean ULiege et al

in Cephalalgia : An International Journal of Headache (2017)

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See detailDevelopment and applications of CRISPR-Cas9 and RNAi for rice and wheat agronomic traits improvement
Sun, Yongwei ULiege

Doctoral thesis (2017)

Genome editing technologies enable precise modifications of DNA sequences in vivo and offer a great promise for harnessing plant genes in crop improvement. The precise manipulation of plant genomes relies ... [more ▼]

Genome editing technologies enable precise modifications of DNA sequences in vivo and offer a great promise for harnessing plant genes in crop improvement. The precise manipulation of plant genomes relies on the induction of DNA double-strand breaks (DSBs) by sequence-specific nucleases (SSNs) to initiate DNA repair reactions that are based on either non-homologous end joining (NHEJ) or homology-directed repair (HDR). NHEJ can result in frame-shift mutations that often create genetic knockouts. These knockout lines are useful for functional and reverse genetic studies but also have applications in agriculture. HDR has a variety of applications as it can be used for gene replacement, gene stacking, and for creating various fusion proteins. An overview of development and applications of precise GT in plants using SSNs systems is presented in Chapter I. Cereals high in amylose content (AC) and resistant starch (RS) offer potential health benefits. Starch branching enzyme (SBE) plays a major role in determining the fine structure and physical properties of starch. Here, we use CRISPR/Cas9 technology to generate targeted mutagenesis in SBEI and SBEIIb in rice. The frequencies of obtained homozygous or bi-allelic mutant lines with indels in SBEI and SBEIIb in T0 generation were from 26.7 to 40%. SbeII mutants showed higher proportion of long chains presented in debranched amylopectin, significantly increased AC and RS content to as higher as 25.0% and 9.8%, respectively. The details of results are presented in Chapter IV Complete knockouts and loss-of-function mutations are very valuable in defining gene functions, their applications in crop improvement are somewhat limited because many agriculturally important traits are conferred by point mutations or a change of gene expression levels. Development of a technology that enables gene replacement rather than gene inactivation will greatly facilitate plant breading. In this study, we report an efficient method to introduce multiple discrete point mutations in the rice ALS gene using CRISPR/Cas9-mediated homologous recombination. We not only generated homozygous herbicide resistance rice plants in one generation, but also demonstrated that the presented strategy is feasible and effective in precise gene replacement by using CRISPR/Cas9 system to facilitate crop genetic improvement. The details of results are presented in Chapter V Aphids are major agricultural pests which cause significant yield losses of wheat each year in China. Present attempts to improve the aphid resistance of wheat through conventional breeding in China are being confronted by slow progress due to lack of aphid resistant wheat germplasm, the complexity of plant-aphid interactions and the rapid development of resistant pest biotypes. An overview of the engineering of plants for aphid resistance is presented in chapter II. We identify a gene (23028) related to aphid ingestion and digestion from the aphid, S. avenae. Aphids fed on plant material expressing double-stranded RNA (dsRNA) specific to 23028 and C002 show a decline in growth, reproduction and survival rates. The details of results presented in the chapter VI. [less ▲]

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See detailGENETIC DIVERSITY AND FACULTATIVE SYMBIONTS INFECTION PATTERNS OF TWO RHOPALOSIPHUM APHIDS
Guo, Jianqing ULiege

Doctoral thesis (2017)

Aphids, during the long-term evolution, kept their genetic traits for continuation of the species while some variations caused by selection, migration, mutation, and genetic drift occurred meanwhile to ... [more ▼]

Aphids, during the long-term evolution, kept their genetic traits for continuation of the species while some variations caused by selection, migration, mutation, and genetic drift occurred meanwhile to adapt to novel environments. The differentiation takes place not only among species but could also be observed within species that finally contributes to the population genetic diversity. However, the migrant behavior of aphid can enhances the gene flow among populations, as a result, decreasing the genetic variation. Additionally, insect such as aphids usually hold the mutualistic relationships with endosymbionts which may affect the adaptive characteristics of the host aphid. Both Corn leaf aphid Rhopalosiphum maidis (F.) (Hemiptera: Aphididae) and Bird cherry-oat aphid Rhopalosiphum padi (L.) (Hemiptera: Aphididae) are worldwidely severe pests that attack cereal crops such as maize, barley, wheat, sorghum and oats. They suck the phloem and can transmit viruses including Maize dwarf mosaic virus (MDMV) and Barley yellow dwarf virus (BYDV), the main virus of maize and barley, which may result in serious damage for the yield and quality of the host plant. Moreover, one aphid species usually exerts genetic differentiation among populations which is related to factors such as geographic conditions, host plants and life history. Hence, it is necessary to have a clear understanding of the genetic structure and variation among geographic populations to further explore the historical expanding routes and occurrence of these pests and design efficient control strategies. Targeting the genetic divergence among populations of two Rhopalosiphum aphids, 32 populations of R. padi and 38 populations of R. maidis were collected on maize from most regions of China as well as some countries in Europe. The sequencing results of two mitochondrial (COI and COII) and one nuclear (EF-1α) genes indicated that a high level of gene flow existed among the populations of R. maidis in terms of geographic locations, proving the migratory capacity of this aphid. With regard to R. padi, high genetic diversity were found between the populations from China and Europe based on combined COI-COII, however, the genetic diversification among Chinese populations and European populations were low, which illustrated that the length of geographic distance may play an important role in genetic diversity. The infection patterns of seven facultative symbionts (Serratia symbiotica, Hamiltonella defensa, Regiella insecticola, Rickettsia, Spiroplasma, Wolbachia and Arsenophonus) in R. padi and R. maidis were investigated as well. Both aphids were found to have wide symbiotic associations with variant symbionts. Unlike Acyrthosiphum pisim (H.) which is frequently infected with S. symbiotica, R. insecticola, Rickettsia and Spiroplasma were dominant facultative symbionts in these two Rhopalosiphum aphids. The results also indicated that the geographic conditions such as latitude of collecting locations may have an effect on the distribution of facultative symbionts, implying the adaptive function of the facultative symbionts to various environmental conditions on their host aphids. Considering the population diversity within species, we also tested the survival and reproduction rates of two R. maidis populations (i.e. Beijing and Mangshi) on barley and maize of small (10 cm) and high (50 cm) size. Direct observation method was used and none of the populations could survive on maize of small size whereas they were capable to develop on maize of high size, but with much lower growing speeds compared with barley on which both populations showed the best performances. In addition, Beijing population was found to perform significantly better than Mangshi population which may be related to the infection of facultative symbionts. We hypothesize that the lethality on small maize may result from the secondary metabolites synthesized to be more abundant in young maize seedlings. [less ▲]

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