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See detailUne phéromone sexuelle chez la coccinelle asiatique, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2014, October)

A ce jour, aucune phéromone sexuelle n’a pu être mise en évidence chez les Coccinellidae. Cependant, diverses études suggèrent que de telles molécules sont impliquées dans la communication sexuelle chez ... [more ▼]

A ce jour, aucune phéromone sexuelle n’a pu être mise en évidence chez les Coccinellidae. Cependant, diverses études suggèrent que de telles molécules sont impliquées dans la communication sexuelle chez les coccinelles. Afin de vérifier cette hypothèse, nous avons collecté les composés organiques volatils émis par la coccinelle asiatique, Harmonia axyridis (Pallas), en présence ou en absence de pucerons. En présence de pucerons, les femelles vierges présentent un « comportement d’appel » qui est notamment associé à l’émission d’une phéromone sexuelle volatile chez plusieurs espèces de Coléoptères. D’autre part, des tests éthologiques ont démontré que les femelles émettent des composés volatils qui attirent les mâles à distance. Enfin, les prélèvements ont été analysés par chromatographie en phase gazeuse couplée à la spectrométrie de masse. Les analyses ont mis en évidence cinq composés volatils spécifiques provenant des femelles, aucun d’entre eux n’étant émis pas les mâles. L’identification a révélé la présence de (–)-β-caryophyllène, de β-élémène, de méthyl-eugénol, d’α-humulène et d’α-bulnésène, exclusivement produits par les femelles nourries de pucerons et dont les quantités respectives augmentent progressivement au cours de la période de prélèvement. Les résultats confirment donc que les femelles H. axyridis produisent une phéromone sexuelle volatile. Ceux-ci devraient permettre de promouvoir le développement de méthodes de gestion plus efficaces afin de manipuler les mouvements de cette coccinelle invasive et de réduire les impacts négatifs qu’elle occasionne sur la biodiversité. [less ▲]

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See detailEvolution des populations de coccinelles indigènes et de l’espèce exotique, Harmonia axyridis Pallas, en Wallonie et en Région de Bruxelles-Capitale
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Conference (2014, October)

Un inventaire des Coccinellidae provenant de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur une période s’étendant de 2001 à 2009. Cette ... [more ▼]

Un inventaire des Coccinellidae provenant de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur une période s’étendant de 2001 à 2009. Cette collection est essentiellement constituée de récoltes fournies par les étudiants de première Bachelier de Gembloux Agro-Bio Tech. A travers ce recensement, nous avons étudié l’évolution des espèces récoltées au sein de cette famille, en termes d’effectif relatif et de richesse spécifique. Notre étude s’est focalisée sur les données issues de Wallonie et de la Région de Bruxelles-Capitale, car trop peu de collectes ont été réalisées en Flandre. Parmi les individus identifiés, 27 espèces ont été observées, dont 21 appartiennent à la sous-famille des Coccinellinae, 2 à celle des Epilachninae et 4 à celle des Chilocorinae. La plupart des espèces sont communes à la Belgique. Cependant, Harmonia axyridis (Pallas 1773), espèce originaire du sud-est de l’Asie, a été introduite sur le territoire belge en 1997. Cette coccinelle exotique a fait son apparition dans les collectes de 2002 et son effectif ne cesse d’augmenter au fil des années prospectées. En parallèle à cette augmentation, une diminution de la richesse spécifique, ainsi que de l’effectif relatif d’Adalia bipunctata (L. 1758), de Propylea quatuordecimpunctata (L. 1758) et de Psyllobora vigintiduopunctata (L. 1758), est observée. [less ▲]

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See detailUnveiling the effects of berenil, a DNA-binding drug, on Trypanosoma cruzi: implications for kDNA ultrastructure and replication.
Zuma, Aline Araujo; Cavalcanti, Danielle Pereira; Zogovich, Marcelo et al

in Parasitology research (2014)

Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits a single mitochondrion with an enlarged portion termed kinetoplast. This unique structure harbors the mitochondrial DNA (kDNA ... [more ▼]

Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits a single mitochondrion with an enlarged portion termed kinetoplast. This unique structure harbors the mitochondrial DNA (kDNA), composed of interlocked molecules: minicircles and maxicircles. kDNA is a hallmark of kinetoplastids and for this reason constitutes a valuable target in chemotherapeutic and cell biology studies. In the present work, we analyzed the effects of berenil, a minor-groove-binding agent that acts preferentially at the kDNA, thereby affecting cell proliferation, ultrastructure, and mitochondrial activity of T. cruzi epimastigote form. Our results showed that berenil promoted a reduction on parasite growth when high concentrations were used; however, cell viability was not affected. This compound caused significant changes in kDNA arrangement, including the appearance of membrane profiles in the network and electron-lucent areas in the kinetoplast matrix, but nuclear ultrastructure was not modified. The use of the TdT technique, which specifically labels DNA, conjugated to atomic force microscopy analysis indicates that berenil prevents the minicircle decatenation of the network, thus impairing DNA replication and culminating in the appearance of dyskinetoplastic cells. Alterations in the kinetoplast network may be associated with kDNA lesions, as suggested by the quantitative PCR (qPCR) technique. Furthermore, parasites treated with berenil presented higher levels of reactive oxygen species and a slight decrease in the mitochondrial membrane potential and oxygen consumption. Taken together, our results reveal that this DNA-binding drug mainly affects kDNA topology and replication, reinforcing the idea that the kinetoplast represents a potential target for chemotherapy against trypanosomatids. [less ▲]

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See detailThe cellobiose-sensor CebR is the gatekeeper of Streptomyces scabies pathogenicity
Jourdan, Samuel ULg; Francis, Isolde; Loria, Rosemary et al

Poster (2014, October)

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See detail2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: The Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC).
Elliott, Perry M.; Anastasakis, Aris; Borger, Michael A. et al

in European heart journal (2014), 35(39), 2733-79

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See detailPre-war Military Planning (Belgium)
Bechet, Christophe ULg

in Daniel, Ute; Gatrell, Peter; Janz, Oliver (Eds.) et al 1914-1918-online. International Encyclopedia of the First World War (2014)

Abstract: Since the Treaty of London in 1839, pre-war planning theories in Belgium oscillated between two positions: on one hand secure and defend which border would be endangered, on the other hand ... [more ▼]

Abstract: Since the Treaty of London in 1839, pre-war planning theories in Belgium oscillated between two positions: on one hand secure and defend which border would be endangered, on the other hand constitute in Antwerp a powerful national sanctuary. This concentration of most of the available military means in Antwerp was far more appropriate in the event of a French invasion. But this perspective decreased after the Franco-Prussian war in 1870, while the possibility of a trespassing by the two belligerents became greater and greater. The fortifications of Namur and Liège were voted by the Chambers in 1887 as a deterrent to both France and Germany. Nevertheless, without totally putting aside the defence of the Belgian southwestern border, high-ranking officers seemed to fear more and more a violation of the eastern border. Due to the completion of fortifications on the Meuse in 1892, German columns were supposed to move forward south of the river, through the Belgian Ardennes. On the eve of the Great War, King Albert I would have preferred to concentrate the army on the Meuse but his Chief of Staff selected a central position in order to maintain and secure his line of communication with Antwerp. The lack of a determined and “standardized” doctrine at the highest level of the army led to a “mixed” or compromise plan adopted in a hurry during the first days of mobilization in August 1914. [less ▲]

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See detailPreparations for the use of Raman spectrometers on Mars
Malherbe, Cédric ULg; Ingley, Richard; Hutchinson, Ian B. et al

Conference (2014, October)

Raman spectroscopy has been selected as a non-destructive powerful analytical method for forthcoming planetary exploration. In the context of the upcoming ExoMars and NASA 2020 missions (developed by the ... [more ▼]

Raman spectroscopy has been selected as a non-destructive powerful analytical method for forthcoming planetary exploration. In the context of the upcoming ExoMars and NASA 2020 missions (developed by the European Space Agency, IKI Roscomos and NASA) analysis of the biological and geological terrestrial analogues using laboratory instrumentation is of great importance; especially testing the performance of flight-like operating modes and conditions on the feasibility of flight instruments meeting their science goals. Here we present a set of measurements of terrestrial analogues (among them desert varnishes) selected in preparation for in-situ Raman analysis on Mars. Laboratory instrumentation has been used to fully characterise the samples in addition to being operated in modes consistent with ExoMars RLS instrument flight designs, sample preparation and delivery. We discuss the performance of the spectrometers regarding the detection of the target signatures and their geological context. The impact of instrument operating modes and application of flight instrument sampling philosophy (i.e. spot size, grain size, number of target locations, sample preparation and delivery) on the signal intensity and the limits of detection are also discussed. [less ▲]

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See detailUsing XCO2 retrievals for assessing the long-term consistency of NDACC/FTIR data sets
Barthlott; Schneider, M; Hase, F et al

in Atmospheric Measurement Techniques. Papers in Open Discussion (2014), 7

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier–Transform InfraRed) spectrometers, spread worldwide, provide long-term data records of many ... [more ▼]

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier–Transform InfraRed) spectrometers, spread worldwide, provide long-term data records of many atmospheric trace gases. We present a method that uses measured and modelled XCO2 for assessing the consistency of these data records. Our NDACC XCO2 retrieval setup is kept simple so that it can easily be adopted for any NDACC/FTIR-like measurement made since the late 1950s. By a comparison to coincident TCCON (Total Carbon Column Observing Network) measurements, we empirically demonstrate the useful quality of this NDACC XCO2 product (empirically obtained scatter between TCCON and NDACC is about 4‰ for daily mean as well as monthly mean comparisons and the bias is 25 ‰). As XCO2 model we developed and used a simple regression model fitted to CarbonTracker results and the Mauna Loa CO2 in-situ records. A comparison to TCCON data suggests an uncertainty of the model for monthly mean data of below 3 ‰. We apply the method to the NDACC/FTIR spectra that are used within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) and demonstrate that there is a good consistency for these globally representative set of spectra measured since 1996: the scatter between the modelled and measured XCO2 on a yearly time scale is only 3 ‰. [less ▲]

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See detailMagnetization of 2-G Coils and Artificial Bulks
Coombs, Tim; Fagnard, Jean-François ULg; Matsuda, Koichi

in IEEE Transactions on Applied Superconductivity (2014), 24(5), 8201005

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See detailIsocinétisme et muscles rotateurs d'épaule
Forthomme, Bénédicte ULg; Crielaard, Jean-Michel ULg; Kaux, Jean-François ULg et al

in Innovations technologiques et préhension (2014, October)

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See detailLa relation extraction-structure-propriétés des polysaccharides : cas des galactomannanes et des alginates
Gillet, Sébastien ULg; Richel, Aurore ULg

Learning material (2014)

Polysaccharides are usually composed of various monosaccharides linked with different glucosidic bonds. Some polysaccharides have hyperbranched structures. Moreover, polysaccharides often have high ... [more ▼]

Polysaccharides are usually composed of various monosaccharides linked with different glucosidic bonds. Some polysaccharides have hyperbranched structures. Moreover, polysaccharides often have high molecular weights, and tend to form aggregates in solution that can mask the behavior of individual macromolecules. In consequence, to characterize the chemical structures, chain conformations and physical properties of polysaccharides is not an easy task. [less ▲]

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See detailEtiology in Parthenius of Nicaea
Vandersmissen, Marc ULg

in Euphrosyne (2014), 42

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See detailDissociation Pathways of Benzylpyridinium “Thermometer” Ions Depend on the Activation Regime: An IRMPD Spectroscopy Study
Morsa, Denis ULg; Gabelica, Valérie ULg; Rosu, Frédéric et al

in Journal of Physical Chemistry Letters (2014), 5

The dissociation of benzylpyridinium “thermometer” ions is widely used to calibrate the internal energy of ions produced in mass spectrometry. The fragmentation mechanism is usually believed to yield a ... [more ▼]

The dissociation of benzylpyridinium “thermometer” ions is widely used to calibrate the internal energy of ions produced in mass spectrometry. The fragmentation mechanism is usually believed to yield a benzylium cation, although recent studies suggest the possibility of a rearrangement leading to the tropylium isomer, which would compromise the accuracy of energy calibrations. In this study, we used IRMPD spectroscopy to probe the dissociation pathways of the p-(tert-butyl)- benzylpyridinium ion. Our results show that the formation of both benzylium and tropylium products is feasible depending on the activation regime and on the reaction time scale. Varying the trapping delays in the hexapole gives insight into a rearrangement mechanism occurring through consecutive reactions with an isomerization from benzylium to tropylium. Our work provides experimental validations for the established calibration procedure and highlights the adequacy of IRMPD spectroscopy to qualitatively resolve gas-phase rearrangement kinetics. [less ▲]

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See detailMathematical Modeling of HIV Dynamics After Antiretroviral Therapy Initiation: A Review
Rivadeneira, Pablo; Moog, Claude; Stan, Guy-Bart et al

in BioResearch Open Acces (2014), 3(5), 233-241

This review shows the potential ground-breaking impact that mathematical tools may have in the analysis and the understanding of the HIV dynamics. In the first part, early diagnosis of immunological ... [more ▼]

This review shows the potential ground-breaking impact that mathematical tools may have in the analysis and the understanding of the HIV dynamics. In the first part, early diagnosis of immunological failure is inferred from the estimation of certain parameters of a mathematical model of the HIV infection dynamics. This method is supported by clinical research results from an original clinical trial: data just after 1 month following therapy initiation are used to carry out the model identification. The diagnosis is shown to be consistent with results from monitoring of the patients after 6 months. In the second part of this review, prospective research results are given for the design of individual anti-HIV treatments optimizing the recovery of the immune system and minimizing side effects. In this respect, two methods are discussed. The first one combines HIV population dynamics with pharmacokinetics and pharmacodynamics models to generate drug treatments using impulsive control systems. The second one is based on optimal control theory and uses a recently published differential equation to model the side effects produced by highly active antiretroviral therapy therapies. The main advantage of these revisited methods is that the drug treatment is computed directly in amounts of drugs, which is easier to interpret by physicians and patients. [less ▲]

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See detailWP2: Drivers of change at sub-global and local scales
Gillet, Pauline ULg; Vermeulen, Cédric ULg; Boulaud, Anne-Laure et al

Conference (2014, October)

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See detailImproved spectral fitting of nitrogen dioxide from OMI in the 405-465 nm window
van Geffen, J H G M; Boersma, K F; Van Roozendael, M et al

in Atmospheric Measurement Techniques. Papers in Open Discussion (2014), 7

An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405–465 nm spectral region is presented. Since the launch of OMI on board NASA's EOS-Aura ... [more ▼]

An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405–465 nm spectral region is presented. Since the launch of OMI on board NASA's EOS-Aura satellite in 2004, DOAS retrievals of NO2 slant column densities have been the starting point for the KNMI DOMINO (v2.0) and NASA SP (v2.1) retrievals. However, recent intercomparisons between NO2 retrievals from OMI and other UV/Vis and limb spectrometers, as well as ground-based measurements, clearly suggested that OMI stratospheric NO2 is biased high. This study revises the OMI NO2 retrieval in detail. The representation of the OMI slit function to convolve high-resolution reference spectra onto the relevant spectral grid is improved. The window used for the wavelength calibration is optimised, leading to much-reduced fitting errors. Ozone and water vapour spectra used in the fit are updated, reflecting the recently improved knowledge on their absorption cross section as documented in the literature. The improved spectral fit also accounts for absorption by the O2–O2 collision complex and by liquid water over clear-water areas. The main changes in the improved spectral fitting result from the updates related to the wavelength calibration: the RMS error of the fit is reduced by 23% and the NO2 slant column by 0.85 × 1015 molec cm-2, independent of latitude, solar zenith angle and NO2 value. Including O2–O2 and liquid water absorption and updating the O3 and water vapour cross-section spectra further reduces NO2 slant columns on average by 0.35 × 1015 molec cm-2, accompanied with a further 9% reduction in the RMS error of the fit. The improved OMI NO2 slant columns are consistent with independent NO2 retrievals to within a range that can be explained by photo-chemically driven diurnal increases in stratospheric NO2 and by small differences in fitting window and fitting approach. The revisions indicate that current OMI NO2 slant columns suffered mostly from an additive, positive offset that is removed by the improved wavelength calibration and representation of the OMI slit function. It is therefore anticipated that the improved NO2 slant columns are most important to retrievals of spatially homogeneous stratospheric NO2 rather than to heterogeneous tropospheric NO2. [less ▲]

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