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See detailIs Büchi's theorem useful for you? (for an audience of logicians)
Rigo, Michel ULg

Conference (2017, January 17)

Almost a century ago, Presburger showed that the first order theory of the natural numbers with addition is decidable. Following the work of B\"uchi in 1960, this result still holds when adding a function ... [more ▼]

Almost a century ago, Presburger showed that the first order theory of the natural numbers with addition is decidable. Following the work of B\"uchi in 1960, this result still holds when adding a function $V_k$ to the structure, where $V_k(n)$ is the largest power of $k\ge 2$ diving $n$. In particular, this leads to a logical characterization of the $k$-automatic sequences. During the last few years, many applications of this result have been considered in combinatorics on words, mostly by J. Shallit and his coauthors. In this talk, we will present this theorem of B\"uchi where decidability relies on finite automata. Then we will review some results about automatic sequences or morphic words that can be proved automatically (i.e., the proof is carried on by an algorithm). Finally, we will sketch the limitation of this technique. With a single line formula, one can prove automatically that the Thue-Morse word has no overlap but, hopefully, not all the combinatorial properties of morphic words can be derived in this way. We will not assume any background in combinatorics on words from the audience. [less ▲]

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See detailLes institutions politiques belges
Grandjean, Geoffrey ULg

Learning material (2017)

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See detailNO Nightglow studies status
Stiepen, Arnaud ULg; Jain; Deighan et al

Conference (2017, January 16)

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See detailLa théorie du complot : un moyen pour expliquer le monde !
Debras, François ULg

Conference given outside the academic context (2017)

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See detailPrésentation de cas cliniques
WANG, François-Charles ULg

Scientific conference (2017, January 16)

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See detailCryopreservation of chicken primordial germ cells by vitrification and slow-freezing: a comparative study
Tonus, Céline ULg; Connan, Delphine ULg; Waroux, Olivier ULg et al

in Theriogenology (2017), 88

In the present study, we compare a classical slow freezing method and an aseptic vitrification technique to cryopreserve a stable Primordial Gem Cells (PGCs) line issued from the Ardennaise chicken breed ... [more ▼]

In the present study, we compare a classical slow freezing method and an aseptic vitrification technique to cryopreserve a stable Primordial Gem Cells (PGCs) line issued from the Ardennaise chicken breed. Viability immediately after warming was close to 80% and did not differ between the two cryopreservation methods. Proliferation tended to be slower for both cryopreservation methods compared to controls, but the difference was significant only for vitrification. No difference was found between the two methods after flow cytometry analysis of SSEA-1 expression and RT-PCR on several factors related to PGCs phenotype. After one week in culture, all cryopreserved cells reached controls main morphological and expanding (viability/proliferation) features. However, slow freezing generated more unwanted cells clusters than vitrification. After injection of the PGCs into recipient embryos, vitrified PGCs showed a clear, yet not significant, tendency to colonize the gonad at a higher rate than slow frozen PGCs. Slow freezing in cryovials remains simple, inexpensive and less technically demanding than vitrification. Nevertheless, the intrinsic advantages of our aseptic vitrification method and the present study suggest that this should be considered as safer than classical slow freezing for cryopreserving chicken PGCs. [less ▲]

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See detailMicrobiological load of edible insects found in Belgium
Caparros Megido, Rudy ULg; Desmedt, Sandrine; Blecker, Christophe ULg et al

in Insects (2017)

Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are ... [more ▼]

Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are sourcing fresh insects from fishing stores or towards traditional markets to find exotic insects that are illegal and not sanitarily controlled. From this perspective, this study aims to characterize the microbial load of edible insects found in Belgium (i.e., fresh mealworms and house crickets from European farms and smoked termites and caterpillars from a traditional Congolese market) and to evaluate the efficiency of different processing methods (blanching for all species and freeze-drying and sterilization for European species) in reducing microorganism counts. All untreated insect samples had a total aerobic count higher than the limit for fresh minced meat (6.7 log cfu/g). Nevertheless, a species-dependent blanching step has led to a reduction of the total aerobic count under this limit, except for one caterpillar species. Freeze-drying and sterilization treatments on European species were also effective in reducing the total aerobic count. Yeast and mold counts for untreated insects were above the Good Manufacturing Practice limits for raw meat, but all treatments attained a reduction of these microorganisms under this limit. These results confirmed that fresh insects, but also smoked insects from non-European trades, need a cooking step (at least composed of a first blanching step) before consumption. Therefore, blanching timing for each studied insect species is proposed and discussed. [less ▲]

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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 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 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 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 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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