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See detailContext-dependent effects of castration and testosterone treatment on song in male European starlings
Pinxten, R.; De Ridder, E.; Balthazart, Jacques ULg et al

in Hormones & Behavior (2002), 42(3), 307-318

Most seasonally breeding songbirds display dramatic seasonal fluctuations in plasma testosterone (T) levels and mate attraction behaviors, including song. However, males of some songbird species, such as ... [more ▼]

Most seasonally breeding songbirds display dramatic seasonal fluctuations in plasma testosterone (T) levels and mate attraction behaviors, including song. However, males of some songbird species, such as the European starling (Stumus vulgaris), continue to sing at high levels after the breeding season, when T levels are basal. In male starlings song during the breeding season functions mainly to attract mates, whereas song during the nonbreeding season appears unrelated to reproduction. This suggests that song produced in a context unrelated to female courtship, unlike song directed toward females, is not regulated by plasma T. In captive males housed in large outdoor aviaries we explored the relationship between plasma T and song produced during the breeding season within and outside a courtship context. This was achieved by determining the effects of castration and subsequent T treatment on song and mate attraction behaviors in both the presence and the absence of a female. Compared to intact males, castrated males did not show reduced song activity in the absence of a female for at least 6 months after the operation, strongly suggesting that the expression of noncourtship song is not regulated by plasma T. Likewise, we found that experimentally elevating T levels in castrated males did not affect noncourtship song rates. However, control castrated males receiving empty implants tended to show reduced noncourtship song rates after implantation. This may have been due to a suppressive effect caused by the presence of the T-implanted castrated males in the same aviary. In contrast, courtship singing was clearly controlled by plasma T: it was abolished by castration and restored by subsequent T replacement when males were housed both individually and in a group situation. High plasma levels of T also appeared necessary for the activation of three other behavioral traits critical for mate attraction, namely, nesthole occupancy, spending time (singing) in a nesthole, and carrying green nesting material into a nesthole. (C) 2002 Elsevier Science (USA). [less ▲]

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See detailContext-related vocalizations in African grey parrots (Psittacus erithacus)
Giret, Nicolas; Albert, Aurélie ULg; Nagle, Laurent et al

in Acta Ethologica (2012), 15

A few animal species are capable of vocal learning. Parrots are well known for their vocal imitation abilities. In this study, we investigated whether African grey parrots (Psittacus erithacus) emit ... [more ▼]

A few animal species are capable of vocal learning. Parrots are well known for their vocal imitation abilities. In this study, we investigated whether African grey parrots (Psittacus erithacus) emit specific vocalizations in specific contexts. We first described the vocal repertoire and its ontogenesis of four captive grey parrots. After a comparison with vocalizations emitted by wild and other captive African grey parrots, we observed that only three call categories were shared by all grey parrots populations, suggesting that isolated populations of parrots develop population-specific calls. Then, we artificially provoked ten different contexts and recorded vocalizations of four captive grey parrots in these situations. Parrots predominantly emitted call categories in some contexts: distress, protestation, alarm, asking (i.e. emitted when a bird wanted something from an experimenter and contact calls. These results suggest that some calls are learned and can be used in specific contexts. [less ▲]

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See detailLe contexte d'édification du Sart Tilman
Frankignoulle, Pierre ULg

in Cahiers de l'Urbanisme (Les) (2005), (n°54-55), 18-23

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See detailContexte de l'enseignement de la francophonie
Defays, Jean-Marc ULg

in Cahiers francophones d'Europe Centre-Orientale (1993), 3

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See detailContexte géologique
Lacroix, Daniel ULg; Gervasoni, Laurence; Laroche, Jean et al

in Bassin hydrographique de la Molignée. Volume 1 : Facteurs abiotiques (1999)

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See detailContexte géologique des sites mésolithiques de la Heid de Fer et de L’Ourlaine à Becco (Theux, Belgique)
Marion, Jean-Marc ULg; Simons, Justine; Mottequin, Bernard ULg

in Autour de l'hématite - Circulation et transformation au cours de la préhistoire récente. Méthodes d'analyse (2013, February)

The use of natural resources is a major source of information to study the socio-economic organization of the population from Prehistory to Antiquity, due to the fact that their exchange networks and ... [more ▼]

The use of natural resources is a major source of information to study the socio-economic organization of the population from Prehistory to Antiquity, due to the fact that their exchange networks and behaviors changed together with their lifestyles and know-how. If flint or other materials such as shale have been extensively studied, haematite, and particularly the oolitic haematite, remains hardly investigated as a material in terms of its origin and technical methods of utilization. The mesolithic sites of "L'Ourlaine" and the "Heid de Fer" (Becco, Theux, southern Belgium) are very close to an important Famennian (Upper Devonian) oolitic haematite outcrop. [less ▲]

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See detailContexte géologique et structural de la région de Rochefort (Synclinorium de Dinant, Belgique)
Marion, Jean-Marc ULg; Mottequin, Bernard ULg; Barchy, Laurent et al

in Geological Survey of Belgium, Profesional Paper (2011), 2011/2(309), 27-38

Realised in the framework of the program “Revision of geological maps of Wallonia” the new geological maps “Rochefort - Nassogne” and “Houyet - Han sur Lesse” have formed the basis for this note. They ... [more ▼]

Realised in the framework of the program “Revision of geological maps of Wallonia” the new geological maps “Rochefort - Nassogne” and “Houyet - Han sur Lesse” have formed the basis for this note. They represent a synthesis and the update of geological knowledge gained since the previous edition (1900), both in terms of lithostratigraphy and tectonics. The identification, exploration and mapping of various rock units in this part of the Dinant Syncline have led several generations of geologists to identify the structural grain of the region. The main tectonic elements encountered on this map are: longitudinal structures of predominantly SSW-NNE direction that include folds of different style and order, normal and reverse faults with occasional lateral slip component, and many smaller fractures as the sets of conjugate faults. Sets of transversal (cutting) faults were also recognized. Folds, located on the fringe of the Ardenne generally expose north-verging “plis-en-chaise” style, with axial plane schistosity. [less ▲]

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See detailContexte global des productions porcine et avicole en 2025
Boudry, Christelle ULg

in 10ème jounrée des productions porcines et avicoles : Nos filières porcines et avicoles vers plus de durabilité (2010, October 13)

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See detailContexte hydrogéologique de la commune de Sprimont
Gesels, Julie ULg; Gilson, Mylene; Brouyère, Serge ULg et al

in Gilles-Sépulchre, Yvette (Ed.) Sprimont, gravé dans la pierre (2014)

Cadre hydrogéologique de la commune de Sprimont : formations géologiques qui contiennent des ressources en eau intéressantes, variations de la profondeur d'eau dans les différentes nappes, volumes ... [more ▼]

Cadre hydrogéologique de la commune de Sprimont : formations géologiques qui contiennent des ressources en eau intéressantes, variations de la profondeur d'eau dans les différentes nappes, volumes exploités et chimisme des eaux souterraines. [less ▲]

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See detailLe contexte lit mineur - lit majeur : approche géomorphologique et sédimentologique
Petit, François ULg

in Actes des Ateliers de l'Eau, organisés par les Facultés Agronomiques de Gembloux (1994)

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See detailContexte pédologique
Bock, Laurent ULg; Laroche, Jean; Gervasoni, Laurence et al

in Bassin hydrographique de la Molignée. Volume 1 : Facteurs abiotiques (1999)

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See detailLe contexte urbain et climatique des risques hydrologiques de la ville de Butembo (Nord Kivu/ RDC)
Sahani, Muhindo; Ozer, Pierre ULg; Moeyersons, Jan

in 8th International conference (IAG) on Geomorphology: « Geomorphology and sustainability », Paris, 27-31 August 2013 (2013, August)

Butembo constitue un cas typique de zone urbaine en région tropicale humide rencontrant une explosion démographique exceptionnelle. La concentration spontanée des populations, due à l’exode incontrôlé sur ... [more ▼]

Butembo constitue un cas typique de zone urbaine en région tropicale humide rencontrant une explosion démographique exceptionnelle. La concentration spontanée des populations, due à l’exode incontrôlé sur un territoire assez restreint, a conduit à une urbanisation sans cesse croissante. L’imperméabilisation des vastes étendues de terres consécutive à une expansion spatiale rapide de la ville a généré des problèmes environnementaux qui affectent la structure urbaine. La ville est actuellement confrontée à des risques hydrologiques diversifiés : ravinements progressif et régressif, inondations, et remobilisation d’anciens glissements de terrain. Après avoir réalisé la carte de la ville de Butembo, ce travail aboutit notamment à la production d’une carte des risques hydrologiques sur base d’approches combinant la télédétection et travaux de terrain. Les résultats révèlent une expansion urbaine exceptionnelle. L’emprise urbaine de la ville de Butembo est passée de 2,39 km² en 1957 à 85,83 km² en 2008. Son accroissement est consécutif à l’augmentation de la population qui est passée de 9 653 à 581 449 habitants entre 1957 et 2008. Cette urbanisation a abouti à une nouvelle affectation du sol avec des conséquences sur le paysage urbain. Depuis 1957, le ravinement de fond de vallée ainsi que celui sur les versants sont toujours restés confinés à l’intérieur des extensions urbaines respectives. L’urbanisation précède le développement des ravins et ceux-ci sont confinés dans les zones où le coefficient d’écoulement est accentué par elle. Les inondations pourraient s’étendre sur tous les fonds plats de vallées en cas d’inaction. Quant aux 16 glissements de terrain actifs, ils se trouvent dans la phase de creep et 11 sont partiellement co-engendrés par la sismicité. La pluie n’est pas à la base de l’accentuation des problèmes environnementaux qui perturbent la structure urbaine de Butembo. C’est bien l’urbanisation qui en est la principale cause. [less ▲]

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See detailLe contexte urbain et climatique des risques hydrologiques de la ville de Butembo (Nord Kivu/RDC)
Muhindo, Sahani ULg

Doctoral thesis (2011)

Butembo, a small town in the humid tropical region, is a typical case of, a city with an exceptionally rapid population growth. The spontaneous concentration of populations due to uncontrolled migration ... [more ▼]

Butembo, a small town in the humid tropical region, is a typical case of, a city with an exceptionally rapid population growth. The spontaneous concentration of populations due to uncontrolled migration on a relatively small territory has led to urban sprawl. Soil sealing of large areas caused by a rapid spatial expansion of the town has generated environmental problems that affect the urban structure. The city is facing diverse hydrological risks. Progressive and regressive gully development accelerates and increasingly affects water availability. In recent years, the urban area faces floods, perceived locally as exceptional. The remobilization of old landslides locally causes damage. Since its inception, Butembo has never had an objective reference map. The only ones which are available are manually drawn. It is known that land use planning can fight effectively against most major risks in so far as the elements that govern their occurrence are known and that the areas at risk can be located and defined on the basis of objective and scientific criteria. The main goal of this thesis is to produce a map of and for the city of Butembo which can help to support decision making or at least to understand the reasons of the environmental degradation in the urban area. In that direction, this thesis leads to editing a map of hydrological risks. It is based on approaches combining remote sensing and terrain activities. A detailed analysis of rainfall events is made to see if the rains did influence the environmental problems in the town of Butembo. The results reveal an exceptional urban expansion. The urban sprawl of Butembo increased from 2,39 km² in 1957 to 85,83 km² in 2008, approximately 54 % of 158,95 km². This increase in urban area is the result of exceptional population growth in the town. Indeed, the population rose from 9 653 in 1957 to 581 449 inhabitants in 2008. This urbanization has resulted in a new land use with all the consequences on the urban landscape. Since 1957 valley and hillslope gullying remained all the time confined spatially within the diachronic urbanized expansions. Urbanization precedes the development of gullies and these are confined to areas where the runoff coefficient increased by urbanization. For the time being, there is not yet fusion between progressive and regressive gullies. In the future, flooding threats all the flat valley bottoms in the case nothing is done. Landslides are active and are in the creep phase. 11 of the 16 landslides inventoried are partially co-triggered by seismic. Finally, the damage to the urban structure cannot be ascribed to changes in the rainfall pattern over the 30 last years. All the rains of recent years are normal for the city as their recurrence time is under 6 years. The main cause of environmental problems within the city is urbanization. Remediation methods require intervention not only in the field of runoff evacuation. The problems must also be tackled upstream, on the slopes, using all the techniques that can prevent or reduce the generation of runoff. [less ▲]

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See detailCOnTEXTES : une revue en open access
Dozo, Björn-Olav ULg

Speech (2013)

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See detailLes contextes alimentaires vus, commentés et dessinés par les adolescents. Recherche sur les représentations et les pratiques socio-alimentaires, selon une démarche multi-méthodologique
D'Amore, Salvatore ULg

in Bulletin de Psychologie (2007), 60(6), 527-544

The objective of this study is to describe the eating representations and practices among 60 Roman high-school boys and girls through a complex methodology scheme that associates different techniques ... [more ▼]

The objective of this study is to describe the eating representations and practices among 60 Roman high-school boys and girls through a complex methodology scheme that associates different techniques (word-association network, semi-directive interviews, test on the drawing of eating contexts, eating attitudes scale). As a result, it emerges that there are two differentiated models of relationship – depending on the sex and the socio-professional category the high-school pupils belong to – to eating and body. A protective model, typical among boys, shows an essentially pleasure-based relationship to eating and body. Eating contexts are lived in a conflicting (family) and play (friends) manner. This model seems to be a factor of preservation against eating pathology risks. On the contrary, a model that presents risks of eating disorders, typical among girls, shows a more complex relationship to eating and to body, characterized by normative aspects that girls shall conform to and/or transgress, according to the eating context. In this kind of relationship, the test on the drawing of the family eating context shows, among other things, the absence of any contact with food. [less ▲]

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See detailCOnTEXTES n°5 : Don et littérature
Dozo, Björn-Olav ULg; Glinoer, Anthony

Book (2009)

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See detailContexts for Mathematics and Science Education, Belgium
Monseur, Christian ULg; Brusselmans, Christiane

in IEA (Ed.) Contexts for Mathematics and Science Education (1997)

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See detailContextual Multi-armed Bandits for the Prevention of Spam in VoIP Networks
Jung, Tobias ULg; Martin, Sylvain ULg; Ernst, Damien ULg et al

E-print/Working paper (2012)

In this paper we argue that contextual multi-armed bandit algorithms could open avenues for designing self-learning security modules for computer networks and related tasks. The paper has two ... [more ▼]

In this paper we argue that contextual multi-armed bandit algorithms could open avenues for designing self-learning security modules for computer networks and related tasks. The paper has two contributions: a conceptual one and an algorithmical one. The conceptual contribution is to formulate -- as an example -- the real-world problem of preventing SPIT (Spam in VoIP networks), which is currently not satisfyingly addressed by standard techniques, as a sequential learning problem, namely as a contextual multi-armed bandit. Our second contribution is to present CMABFAS, a new algorithm for general contextual multi-armed bandit learning that specifically targets domains with finite actions. We illustrate how CMABFAS could be used to design a fully self-learning SPIT filter that does not rely on feedback from the end-user (i.e., does not require labeled data) and report first simulation results. [less ▲]

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See detailContextual Multi-armed Bandits for Web Server Defense
Jung, Tobias ULg; Martin, Sylvain ULg; Ernst, Damien ULg et al

in Hussein, Abbas (Ed.) Proceedings of 2012 International Joint Conference on Neural Networks (IJCNN) (2012)

In this paper we argue that contextual multi-armed bandit algorithms could open avenues for designing self-learning security modules for computer networks and related tasks. The paper has two ... [more ▼]

In this paper we argue that contextual multi-armed bandit algorithms could open avenues for designing self-learning security modules for computer networks and related tasks. The paper has two contributions: a conceptual and an algorithmical one. The conceptual contribution is to formulate the real-world problem of preventing HTTP-based attacks on web servers as a one-shot sequential learning problem, namely as a contextual multi-armed bandit. Our second contribution is to present CMABFAS, a new algorithm for general contextual multi-armed bandit learning that specifically targets domains with finite actions. We illustrate how CMABFAS could be used to design a fully self-learning meta filter for web servers that does not rely on feedback from the end-user (i.e., does not require labeled data) and report first convincing simulation results. [less ▲]

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