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See detailLandscape ecological consequences of the (sub)urbanization process in an African city: Lubumbashi (Democratic Republic of Congo)
Andre, Marie ULg

Doctoral thesis (2017)

If anthropogenic effect is a general term accounting for the influence of human activities on environment, it may also designate specific influences that may be inter- and intralinked. Thus, urbanization ... [more ▼]

If anthropogenic effect is a general term accounting for the influence of human activities on environment, it may also designate specific influences that may be inter- and intralinked. Thus, urbanization and suburbanization are anthropogenic processes contributing to the broad anthropogenic effect. They hide in turn other subprocesses of land transformation that will be called here the secondary spatial impacts. However, although the growing influence of the latter processes, they are still not defined consensually nor exist a comprehensive and applied-oriented methodology to delimit them. The general objective of this thesis is to develop a spatially explicit methodology to evaluate the landscape ecological consequences of the urbanization and suburbanization processes, taking a representative city of Sub-Saharan Africa as a case study: Lubumbashi (Democratic Republic of Congo), and the last decade as the period of study. That general objective is addressed through two themes, to which correspond specific objectives. The first theme concerns the evaluation of the anthropogenic land use and land cover dynamics and the second one proposes a methodology to evaluate the expansion of urban and suburban areas, in relation with consistent definitions of the areas in the urban-rural gradient. For both themes, the propositions are based on remote sensing techniques and landscape ecology metrics. Results show that the region of Lubumbashi underwent a global anthropisation increase mostly constituted of minor rises of anthropisation levels but impacting mainly the most natural landscape classes. Urban and suburban areas were located through the use of the proportion of built-up metric, the secondary spatial impact area through the use of adjacencies of the less natural landscape patches. The growth shape of the urban and suburban areas is concentric, except in the south-western part of the city where an affluent of the river Kafubu and its adjacent wetlands slow the urban expansion. The secondary spatial impact area dynamics seems determined, in the north-west, by the relief and, in the north-east, by a transportation axis. It is the latter dynamics that is dominant for the period. It corresponds to the so-called savanisation process, probably due to wood fuel and charcoal production. The methodologies developed here could be improved by taking connectedness into account, by using an additional configuration metric for the definition of urban areas or by taking advantage of spatially explicit socio-economic data. They could also be tested on mining sites, other cities and/or using images of different spatial resolution. [less ▲]

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See detailIron, zinc and manganese interaction within the frd3 Arabidopsis mutant
Scheepers, Maxime ULg; Spielmann, Julien ULg; Goormaghtigh, Erik et al

Poster (2017, January 12)

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See detailTracking the Subtle Mutations Thriving Host Sensing by the Plant Pathogen Streptomyces scabies
Deflandre, Benoit ULg; Jourdan, Samuel ULg; Francis, Isolde Maria et al

Poster (2017, January 12)

Le modèle de la pathogénicité végétale chez les Streptomyces, S. scabies est responsable de la maladie de la galle commune. La thaxtomine est la phytotoxine qui cause cette maladie. Il y a peu, la voie de ... [more ▼]

Le modèle de la pathogénicité végétale chez les Streptomyces, S. scabies est responsable de la maladie de la galle commune. La thaxtomine est la phytotoxine qui cause cette maladie. Il y a peu, la voie de production de la toxine a été découverte : celle-ci met en oeuvre un double mécanisme de régulation génétique. Cependant, certains aspects de la perception de son hôte par le pathogène sont toujours inconnus. Dans ce poster, nous proposons plusieurs hypothèses pour expliquer comment quelques éléments subtiles peuvent être à l'origine de ce mécanisme de pathogénicité. [less ▲]

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See detailWhat is the use of shaping a tang? Tool use and hafting of tanged tools in the Aterian of Northern Africa
Tomasso, Sonja ULg; Rots, Veerle ULg

in Archaeological and Anthropological sciences (2017)

We present the results of detailed microscopic examination of tanged tools from the site of Ifri n'Ammar. The rock shelter has a particularly rich and well-preserved stratigraphy that has yielded a large ... [more ▼]

We present the results of detailed microscopic examination of tanged tools from the site of Ifri n'Ammar. The rock shelter has a particularly rich and well-preserved stratigraphy that has yielded a large variety of tanged tools, thus offering a possibility to test hypotheses on the possible links between tangs and hafting. Earlier methodological work has demonstrated that patterned wear forms on the non-active part of the tool as the result of hafted tool use, and that the characteristics of the wear traces depend on the exact hafting arrangement used. In the present study, wear analyses were combined with further experiments that involved the hafting of tanged tools with various materials and arrangements and aimed at understanding the development of this important morphological innovation. We suggest that functional data are needed to understand the relevance of the "Aterian tang" for hafting (or use), and whether this innovation was triggered by functional, cultural or environmental factors. [less ▲]

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See detailAtypical composition and structure of the mitochondrial dimeric ATP synthase from Euglena gracilis
Yadav, K.N. Sathish; Miranda Astudillo, Héctor Vicente ULg; Colina-Tenorio, Lili et al

in Biochimica et Biophysica Acta-Bioenergetics (2017), 1858(4), 267-275

Mitochondrial respiratory-chain complexes from Euglenozoa comprise classical subunits described in other eukaryotes (i.e. mammals and fungi) and subunits that are restricted to Euglenozoa (e.g. Euglena ... [more ▼]

Mitochondrial respiratory-chain complexes from Euglenozoa comprise classical subunits described in other eukaryotes (i.e. mammals and fungi) and subunits that are restricted to Euglenozoa (e.g. Euglena gracilis and Trypanosoma brucei). Here we studied the mitochondrial F1FO-ATP synthase (or Complex V) from the photosynthetic eukaryote E. gracilis in detail. The enzyme was purified by a two-step chromatographic procedure and its subunit composition was resolved by a three-dimensional gel electrophoresis (BN/SDS/SDS). Twenty-two different subunits were identified by mass-spectrometry analyses among which the canonical alpha, beta, gamma, delta, epsilon and OSCP subunits, and at least seven subunits previously found in Trypanosoma. The ADP/ATP carrier was also associated to the ATP synthase into a dimeric ATP synthasome. Single-particle analysis by transmission electron microscopy of the dimeric ATP synthase indicated that the structures of both the catalytic and central rotor parts are conserved while other structural features are original. These new features include a large membrane-spanning region joining the monomers, an external peripheral stalk and a structure that goes through the membrane and reaches the inter membrane space below the c-ring, the latter having not been reported for any mitochondrial F-ATPase. [less ▲]

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See detailLa transformation de la pensée politique dans les Pays-Bas entre xve et xvie siècles
Dumont, Jonathan ULg

Scientific conference (2017, January 11)

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See detailElevated carbon dioxide concentration reduces alarm signaling in aphids
Boullis, Antoine ULg; Fassotte, Bérénice ULg; Sarles, Landry ULg et al

in Journal of Chemical Ecology (2017), 43

Insects often rely on olfaction to communicate with surrounding conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in ... [more ▼]

Insects often rely on olfaction to communicate with surrounding conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations will impact pheromonal communication by insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide (CO2) affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid Acyrthosiphon pisum under ambient and elevated CO2 concentrations for several generations. We found that an increase in CO2 concentration reduced the production (i.e., individual content) and emission of Eβf (released under predation events). While no difference in Eβf neuronal perception was observed, we found that an increase in CO2 strongly reduces the escape behavior expressed by an aphid colony following exposure to natural doses of the alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases do impact chemical communication in insects, and could potentially have a cascade effect on interactions with higher trophic levels. [less ▲]

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See detailFermi-LAT kills dark matter interpretations of AMS-02 data. Or not?
Belotsky, Konstantin; Budaev, Ruslan; Kirillov, Alexander et al

in Journal of Cosmology and Astroparticle Physics (2017)

A number of papers attempt to explain the positron anomaly in cosmic rays, observed by PAMELA and AMS-02, in terms of dark matter (DM) decays or annihilations. However, the recent progress in cosmic gamma ... [more ▼]

A number of papers attempt to explain the positron anomaly in cosmic rays, observed by PAMELA and AMS-02, in terms of dark matter (DM) decays or annihilations. However, the recent progress in cosmic gamma-ray studies challenges these attempts. Indeed, as we show, any rational DM model explaining the positron anomaly abundantly produces final state radiation and Inverse Compton gamma rays, which inevitably leads to a contradiction with Fermi-LAT isotropic diffuse gamma-ray background measurements. Furthermore, the Fermi-LAT observation of Milky Way dwarf satellites, supposed to be rich in DM, revealed no significant signal in gamma rays. We propose a generic approach in which the major contribution to cosmic rays comes from the dark matter disc and prove that the tension between the DM origin of the positron anomaly and the cosmic gamma-ray observations can be relieved. We consider both a simple model, in which DM decay/annihilate into charged leptons, and a model-independent minimal case of particle production, and we estimate the optimal thickness of DM disk. Possible mechanisms of formation and its properties are briefly discussed. [less ▲]

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See detailPrevalence, location and concurrent diseases of ultrasonographic cyst-like lesions of abdominal lymph nodes in dogs.
Liotta, Annalisa Pia; Billen, Frédéric ULg; Heimann, Marianne et al

in The Veterinary record (2017)

Lymph nodal cyst-like lesions are occasionally identified during abdominal ultrasound in dogs. However, a study evaluating their prevalence and clinical significance is lacking. The aim of this ... [more ▼]

Lymph nodal cyst-like lesions are occasionally identified during abdominal ultrasound in dogs. However, a study evaluating their prevalence and clinical significance is lacking. The aim of this observational cross-sectional study was to evaluate prevalence, most common location and concurrent diseases of cyst-like lymph nodes detected during abdominal ultrasound. Affected lymph nodes, patient signalment and concurrent diseases of dogs with cyst-like lymph nodal lesions having undergone abdominal ultrasound over a one-year period were recorded. Twenty-three affected lymph nodes were observed in 17/553 dogs (prevalence=3 per cent). The most commonly affected was the lumbar lymphocenter (7/23), followed by the coeliac (6/23), the cranial mesenteric (5/23) and the iliosacral (5/23). Twenty-three concurrent diseases were diagnosed in 17 dogs, among which 16/23 were non-neoplastic (70 per cent). The most common concurrent disease was renal insufficiency (8/23), followed by neoplasia (7/23), gastroenteropathy (3/23), benign prostatic disease (2/23), pancreatitis (1/23), peritonitis (1/23) and neurological disease (1/23). No statistical correlation existed between cyst-like lymph nodal lesion and a specific neoplastic or non-neoplastic disease. In conclusion, in the present study, cyst-like lymph nodal lesions have a low prevalence, involve different lymphocenters and were found in dogs affected by different diseases, including both non-neoplastic and neoplastic aetiologies. [less ▲]

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See detailSimultaneous anionic ring-opening and condensation reactions for the synthesis of aliphatic–N-alkyl aromatic copolyamides
Bakkali-Hassani, Camille; Tunc, Deniz; Roos, Kevin et al

in Macromolecules (2017), 50(1), 175-181

The copolymerization of ε-caprolactam with ethyl 4-(butylamino)benzoate was shown to occur in the presence of sodium salts and an acyllactam as activator in a one-step bulk reaction. The mechanism is ... [more ▼]

The copolymerization of ε-caprolactam with ethyl 4-(butylamino)benzoate was shown to occur in the presence of sodium salts and an acyllactam as activator in a one-step bulk reaction. The mechanism is based on the deprotonation of the two monomers yielding activated species able to attack an acyllactam or an ester group at the polymer chain ends. Novel copolyamides with different percentages of aromatic/aliphatic units were synthesized in a one-step bulk copolymerization within a few minutes at 140 °C and characterized by NMR spectroscopy, size exclusion chromatography, and thermal analysis (DSC). This methodology, combining simultaneous anionic ring-opening and condensation reactions, affords a new synthetic pathway to introduce an aromatic unit in an aliphatic polyamide backbone, and more specifically a polyamide 6 containing about 20 mol % of N-alkyl aromatic amides was prepared. [less ▲]

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See detailEffect of extraction pH on techno-functional properties of crude extracts from wild cardoon (Cynara cardunculus L.) flowers
Ben Amira, Amal ULg; Makhlouf, Ines; Petrut, Raul Flaviu et al

in Food Chemistry (2017), 225

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See detailLa grande dépression (1929-1935)
Geerkens, Eric ULg

Conference given outside the academic context (2017)

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See detailRe-emergence of the Schmallenberg virus associated triad hydranencephaly-micromyelia-arthrogryposis in a newborn calf in Belgium, 2016
Bayrou, Calixte ULg; Garigliany, Mutien-Marie ULg; Cassart, Dominique ULg et al

in Veterinary Record Case Reports (2017), 4(1), 000342

Schmallenberg virus (SBV) emerged in Germany in 2011, then spread rapidly across Europe, causing an epizootic outbreak of abortion, stillbirth and birth at term of lambs, kids and calves with neurological ... [more ▼]

Schmallenberg virus (SBV) emerged in Germany in 2011, then spread rapidly across Europe, causing an epizootic outbreak of abortion, stillbirth and birth at term of lambs, kids and calves with neurological signs and/or musculo-skeletal malformations. SBV-associated disease in newborns disappeared in Belgium in 2013. Here, we describe a SBV genomic RNA-positive malformed calf born in May 2016. It reveals the return of SBV circulation during the fall 2015 in the said area. [less ▲]

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See detailFirst scattered-light images of the gas-rich debris disk around 49 Ceti
Choquet, É.; Milli, J.; Wahhaj, Z. et al

in Astrophysical Journal Letters (2017), 834(2), 12

We present the first scattered-light images of the debris disk around 49 ceti, a ~40 Myr A1 main sequence star at 59 pc, famous for hosting two massive dust belts as well as large quantities of atomic and ... [more ▼]

We present the first scattered-light images of the debris disk around 49 ceti, a ~40 Myr A1 main sequence star at 59 pc, famous for hosting two massive dust belts as well as large quantities of atomic and molecular gas. The outer disk is revealed in reprocessed archival Hubble Space Telescope NICMOS F110W images, as well as new coronagraphic H band images from the Very Large Telescope SPHERE instrument. The disk extends from 1.1" (65 AU) to 4.6" (250 AU), and is seen at an inclination of 73degr, which refines previous measurements at lower angular resolution. We also report no companion detection larger than 3 M_Jup at projected separations beyond 20 AU from the star (0.34"). Comparison between the F110W and H-band images is consistent with a grey color of 49 ceti's dust, indicating grains larger than >2microns. Our photometric measurements indicate a scattering efficiency / infrared excess ratio of 0.2-0.4, relatively low compared to other characterized debris disks. We find that 49 ceti presents morphological and scattering properties very similar to the gas-rich HD 131835 system. From our constraint on the disk inclination we find that the atomic gas previously detected in absorption must extend to the inner disk, and that the latter must be depleted of CO gas. Building on previous studies, we propose a schematic view of the system describing the dust and gas structure around 49 ceti and hypothetic scenarios for the gas nature and origin. [less ▲]

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See detailBiocompatibility of polymer-infiltrated-ceramicnetwork (PICN) materials with Human Gingival Keratinocytes (HGKs)
GRENADE, Charlotte ULg; Gillet, Marie-Claire ULg; PIRARD, Catherine ULg et al

in Dental Materials (2017), 33

Objective. Biocompatibility of polymer-infiltrated-ceramic-network (PICN) materials, a new class of CAD–CAM composites, is poorly explored in the literature, in particular, no data are available regarding ... [more ▼]

Objective. Biocompatibility of polymer-infiltrated-ceramic-network (PICN) materials, a new class of CAD–CAM composites, is poorly explored in the literature, in particular, no data are available regarding Human Gingival Keratinocytes (HGK). The first objective of this study was to evaluate the in vitro biocompatibility of PICNs with HGKs in comparison with other materials typically used for implant prostheses. The second objective was to correlate results with PICN monomer release and indirect cytotoxicity. Methods. HGK attachment, proliferation and spreading on PICN, grade V titanium (Ti), yttrium zirconia (Zi), lithium disilicate glass-ceramic (eM) and polytetrafluoroethylene (negative control) discs were evaluated using a specific insert-based culture system. For PICN and eM samples, monomer release in the culture medium was quantified by high performance liquid chromatography and indirect cytotoxicity tests were performed. Results. Ti and Zi exhibited the best results regarding HGK viability, number and coverage. eM showed inferior results while PICN showed statistically similar results to eM but also to Ti regarding cell number and to Ti and Zi regarding cell viability. No monomer release from PICN discs was found, nor indirect cytotoxicity, as for eM. Significance. The results confirmed the excellent behavior of Ti and Zi with gingival cells. Even if polymer based, PICN materials exhibited intermediate results between Ti–Zi and eM. These promising results could notably be explained by PICN high temperature–high pressure (HT–HP) innovative polymerization mode, as confirmed by the absence of monomer release and indirect cytotoxicity [less ▲]

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See detailGeneralized Pascal triangles for binomial coefficients of words: a short introduction
Stipulanti, Manon ULg

Conference (2017, January 09)

We introduce a generalization of Pascal triangle based on binomial coefficients of finite words. These coefficients count the number of times a finite word appears as a subsequence of another finite word ... [more ▼]

We introduce a generalization of Pascal triangle based on binomial coefficients of finite words. These coefficients count the number of times a finite word appears as a subsequence of another finite word. Similarly to the Sierpiński gasket that can be built as the limit set, for the Hausdorff distance, of a convergent sequence of normalized compact blocks extracted from Pascal triangle modulo 2, we describe and study the first properties of the subset of [0, 1] × [0, 1] associated with this extended Pascal triangle modulo a prime p. [less ▲]

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