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See detailL'évolution psychodynamique à moyen terme du processus vocationnel chez le grand adolescent. Etudes de cas.
Stassart, Martine ULg

Doctoral thesis (1995)

The author presents a detailed story of six adolescents from 18 to 22 years from the point of view of their evolution in the field of vocational choice.

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See detailEvolution psychodynamique à moyen terme du processus vocationnel chez le grand adolescent. Le Rorschach
Stassart, Martine ULg

Doctoral thesis (1995)

The author has examined thirty 18 years old adolescents with help of the Rorschachtest. These subjects were examined a second time 4 years later. The question is :"What about changement"

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See detailEvolution psychodynamique à moyen terme du processus vocationnel chez le grand adolescent. Le TAT
Stassart, Martine ULg

Doctoral thesis (1995)

The author has examined thirty 18years aged adolescents with help of the TAT. These subjects were again tested in a second time, 4 years later. What evolution between 18 and 22 years?

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See detailEvolution psychodynamique à moyen terme du processus vocationnel chez le grand adolescent. Motivation
Stassart, Martine ULg

Doctoral thesis (1995)

In the Preface of their Research, the author examines from a theorical point of view the problem of motivation.

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See detailEvolution récente de l'incidence des fractures de hanche et de la consommation de médicaments anti-ostéoporotiques en Belgique
Hiligsmann, Mickaël ULg; Bruyère, Olivier ULg; Roberfroid, D. et al

in Revue du Rhumatisme (2011, December), 78(Suppl. 5), 43-44

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See detailEvolution récente de la distribution et shopping centers. En exemple le shopping center de Genk.
Merenne-Schoumaker, Bernadette ULg

in Bulletin de la Société Géographique de Liège (1970), (6), 91-119

Highlighting changes in the distribution (1960-1970) and more specific analysis of the "shopping centers " by studying the case of the Shopping center of Genk, the first having been opened in Belgium

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See detailEvolution récente de quelques principes du droit de l'environnement et de l'urbanisme
Pâques, Michel ULg

in Questions choisies de droit de l'urbanisme et de l'environnement (2007)

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See detailEvolution récente des extrêmes pluviométriques en Mauritanie (1933-2010)
Ozer, Pierre ULg; Hountondji, Yvon-Carmen; Gassani, Jean et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du 27e Colloque International de l'Association Internationale de Climatologie (2014)

Un ensemble d’indicateurs a été compilé pour vérifier si la fréquence et/ou l’intensité des précipitations a significativement évolué au cours des dernières décennies dans la République Islamique de ... [more ▼]

Un ensemble d’indicateurs a été compilé pour vérifier si la fréquence et/ou l’intensité des précipitations a significativement évolué au cours des dernières décennies dans la République Islamique de Mauritanie. Cette étude s’appuie sur des indices nationaux basés les séries quotidiennes de précipitations de neuf stations synoptiques qui couvrent la période 1933-2010. L’analyse des précipitations a été réalisée en calculant annuellement treize indices pluviométriques : le total pluviométrique (PTOT), le nombre total de jours humides (précipitations ≥1 mm, JP), la lame d’eau moyenne précipitée par jour humide (Simple day intensity index, SDII), la pluviométrie maximale enregistrée sur 1 jour (Px1J), la fréquence des événements pluviométriques ≥ 10 mm (P10), ≥ 20 mm (P20), intenses (P95) et extrêmes (P99). Le poids relatif des cinq derniers indices dans le total pluviométrique annuel étant également apprécié. Les résultats montrent que les indices PTOT, JP, P10 et P20 présentent une tendance à la baisse significative sur la période 1933-2010. Dans le même temps, la fréquence des précipitations intenses et extrêmes évolue peu. De facto, la lame d’eau moyenne précipitée par jour humide (SDII) augmente de manière significative. Les résultats obtenus vont dans le sens des conclusions du Groupe d’expert intergouvernemental sur l’évolution du climat (Giec) à l’échelle globale, à savoir des précipitations extrêmes inchangées dans un contexte global de dessiccation. Selon de nombreux modèles, la dégradation pluviométrique pourrait s’amplifier dans les décennies à venir. Dès lors, des stratégies d’adaptation transfrontalières devraient être envisagées d’urgence car le processus de réchauffement de la planète n'est pas susceptible de diminuer dans les prochaines décennies. [less ▲]

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See detailEVOLUTION RECENTE DES EXTREMES PLUVIOMETRIQUES ET DES TEMPERATURES A DJIBOUTI
Mahamoud, Ayan; Laminou Manzo, Ousmane; Ozer, Pierre ULg

in Boko, Michel; Vissin, Expédit W.; Afouda, Fulgence (Eds.) CLIMAT, AGRICULTURE & RESSOURCES EN EAU d'hier à demain (2013, September)

A dataset of 19 derived indicators has been compiled to clarify whether the frequency and / or the severity of rainfall and temperature extremes changed over the last decades in the city of Djibouti in ... [more ▼]

A dataset of 19 derived indicators has been compiled to clarify whether the frequency and / or the severity of rainfall and temperature extremes changed over the last decades in the city of Djibouti in East Africa. This study uses the only current available coverage of homogenous daily series which can be used for calculating any significant change in rainfall and temperature in recent years. It covers the 1980–2011 period for precipitation and the 1966–2011 period for what regards maximum, minimum and mean temperature. Results show that the annual total precipitation, the annual total of wet days and the frequency of intense rainfall have strongly declined over the last 32 years. Yet, since 2007, mean yearly rainfall meets a 73% deficit when compared to the 30-year average, a situation that is much worse than what was observed in the early 1980s. For what regards temperatures, the average increase recorded during the 1966–2011 period is of +0.28°C per decade, a far higher value than the global rising temperature. Heatwaves characterized by daily maximum temperatures ≥45°C (that is the 99th percentile) have become 15 times more frequent than in the past (comparing the 1966–75 and 2002–2011 periods) while extremely cool nights (<18.7°C, that is the 1st percentile in minimum temperature) have almost disappeared. Although the database should be extended to improve the global picture of recent climate changes in Djibouti, it seems very likely that rainfall shortages and increasing temperature extremes have already impacted the people of the Republic of Djibouti, especially the water availability and health sectors. [less ▲]

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See detailEvolution récente des grands "centres commerciaux" en Belgique (1974-1975).
Merenne-Schoumaker, Bernadette ULg

in Bulletin de la Société Géographique de Liège (1976), (12), 51-63

Study of four new shopping centers open in 1974-1975 and analysis of the evolution of seven other centers

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See detailÉvolution récente des précipitations de mars-mai en Afrique de l'Est: configurations spatiales et évolution sub-saisonnière
Philippon, Nathalie; Camberlin, Pierre; Moron, Vincent et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du 27e Colloque International de l'Association Internationale de Climatologie (2014)

Using raingauge daily rainfall data documenting the Horn of Africa and the Long Rains over the period 1961-2012, the aim of this study is three-fold:1/ confirming the drying trend detected by Lyon et ... [more ▼]

Using raingauge daily rainfall data documenting the Horn of Africa and the Long Rains over the period 1961-2012, the aim of this study is three-fold:1/ confirming the drying trend detected by Lyon et DeWitt (2012) during the Long Rains using gridded rainfall, 2/ understanding how this drying is expressed at the intraannual time scale using the sub-seasonal scenario approach developed by Moron et al. (2013) and 3/ assess its impact on vegetation. A drying is actually measured using raingauge data but is less severe than the one measured using gridded data. It is the strongest at the driest stations and during the rainfall climatological peak (April). It seems to be associated with a higher frequency of the dry subseasonal scenarios i.e. characterized by negative rainfall anomalies through the whole or the core of the seasonal cycle. But we don't observe yet a diminution of the vegetation photosynthetic activity in response to the rainfall decrease. To the contrary, the Rainfall Use Efficiency (RUE) displays a slightly positive trend. [less ▲]

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See detailÉvolution récente du droit des étrangers en Belgique
Carlier, Jean-Yves ULg

in Andersen, R.; Hubeau, B.; Schuermans, G. (Eds.) La médiation et les étrangers (2008)

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See detailEvolution récente du statut de la loutre dans le Parc National des Cévennes
Fonderflick, Jocelyn; De Kermabon, Jean; Libois, Roland ULg et al

in Cahiers d'Ethologie (1995), 15(2-3-4), 233-238

In the south east of the Massif central, the Cevennes National Park covers the area along the dividing line between the Atlantic and Mediterranean catchment areas. The climatic conditions of these medium ... [more ▼]

In the south east of the Massif central, the Cevennes National Park covers the area along the dividing line between the Atlantic and Mediterranean catchment areas. The climatic conditions of these medium-sized mountains are very varied, with a high degree of seasonnality affecting the hydrologic regime of the rivers. The otter seems to have disappeared from that region around the 1960's. Some years ago, evidence was found again ona regular basis in some of these rivers. From 1990, the evolution of this otter population has been monitored by systematic observation of their signe in the principal watercourses covering an area of about 3000 km². At the same time, a preliminary study of the diet (spraint analysis) has been undertaken. Otter signs have been first evidenced on the upper reaches of the rivers Tarn and Lot. In subsequent years, signs have been disovered on some tributaries and on a watercourse flowing to the Mediterranean side: the river Luech. In the river Tarn (upper barbel zone), the most frequent prey is the gudgeon, reaching more than 50% of the total number of prey. However, when the biomass intake is considered, the barbel appears to play the major role, accounting for 46 % of the total food intake. The occurrence of the brown trout (11 %) and its relative biomass (18 %) are weak when compared with the composition of the river fish fauna (25 to 43 % of the estimated fish biomass). [less ▲]

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See detailEvolution régressive récente de la végétation des tourbières hautes à sphaignes en Haute Ardenne (Hautes-Fagnes, Belgique)
Hindryckx, Marie-Noëlle ULg

Doctoral thesis (1999)

In temperate Europe, intact raised bogs from Northern Germany to the French Massif Central are part of rare postglacial ecosystems that one can consider as natural or very close to the natural state ... [more ▼]

In temperate Europe, intact raised bogs from Northern Germany to the French Massif Central are part of rare postglacial ecosystems that one can consider as natural or very close to the natural state. Unfortunately, many of them have been degraded or highly disturbed by intense human activities. Some of them, however, kept a subintact central part. This is the case for the three big raised bogs situated in the Hautes-Fagnes plateau in Belgium: the fagne Wallonne, the fagne de Clefaye and the Misten raised bogs. Their vegetation belongs to the Vaccinio oxycocci-Sphagnetea magellanici Br.-Bl. & Tx. 43 and Eriophoro vaginati-Sphagnetalia papillosi Tx. 70. But the legal conservation measures are not sufficient to guarantee their protection : in the course of the last 30 years, 10 to 25% of the area covered with intact raised bogs of the Hautes-Fagnes plateau have been degraded, mainly invaded by Molinia caerulea. Although it is important to bring forward such alarming observations, it is more essential to understand exactly the origin of the factors causing the degradation, if suitable measures to thwart the factors that condition them, and try to attenuate if not suppress their harmful effects, and thereby restore the conditions that will enable the natural vegetation from these environments to recover the lost areas. Here are the main objectives of this work: • To highlight the current and recent ecological and phytodynamic consequences of the degradation of the raised bogs; • To identify and date the causes of the degradation that struck the intact parts of the raised bogs present on the Hautes-Fagnes plateau; • To examine the practical management measures in the short-, medium-, and long-term taken in Belgium and abroad in order to restore the natural evolution of the peatlands. Studies of the vegetation The vegetation maps, on a scale of 1/250, indicate that, despite some differences, the degradation phenomenon seems to begin in the same way in the three bogs. We can notice: • an invasion by Molinia caerulea of the intact peat areas (in sometimes very high tussocks) but also its presence, in a more diffuse form, within the -narrowzones of transition and even among typical bog species; • a soil draining, resulting in the proliferation of Ericaceae, especially around relatively intact zones; • the existence of Deschampsia flexuosa, which seems to be linked to rather steep slopes at the edge of zones exclusively colonised by Molinia caerulea,; • the poor representation, both in terms of quality as quantity, of bryophytes; fewer than 10 species of peatmosses occur in these peatlands, where they are often little or ill-developed; • the occupation of peat bogs by relatively exclusive species (Empetrum nigrum, Molinia caerulea and other very thick Ericaceae bushes) which prevent other peat forming communities from developing. The analysis of the vegetation releves taken along three transects shows that the Misten bog appears as the most intact one (or the best preserved one) based on the cover, distribution and vitality of peatmosses, although as indicated by the vegetation map, Molinia caerulea surrounds this raised bog. The fagne de Clefaye peat bog seems much drier and the percentage of peatmosses cover is lower compared to the Misten bog. Some Empetrum nigrum clumps no longer contain any mosses. On the other hand, this bog holds more Sphagnum species than either of the other two bogs investigated. The raised bog of the fagne Wallonne is the most degraded one (at least the north-west part of it). The complexity of the problem composed already the focus of several studies as part of a graduate work. In order to have some idea of the evolution of the vegetation, all the releves which have been carried out along the transects of the three bogs have been the subject of an observation follow-up. Even if six or seven years between the vegetation releves is too short a time to show some significant evolution in a peat bog, the results nonetheless enable to bring to the fore some trends in the evolution of the vegetation present in the main bogs of the haut-plateau, Along the itemised transect, the vegetation of the peat bog seems to be stable and optimal for a peat forming activity typical of an ombrotrophic raised bog, to develop. The northern part of the fagne Wallonne bog shows much more worrying signs of evolution (heaths developing quickly) or signs of degradation of its vegetation (reduction of the number of peatmosses, increasing density of Molinia caerulea, and invasion by Betula alba subsp. glutinosa). The vegetation of the fagne de Cléfaye bog clearly evolves towards a drier phase (high intensification of heaths development) without leading to the rarefaction of peatmosses. We wanted to put these evolutional studies in a broader context and take advantage of previous studies carried out on the haut-plateau in similar conditions. Despite the interpretation difficulties that were met, the different studies allow to assert that there has been a quick change in the vegetation of the raised bogs in the last forty years. Are we in the presence of a Natural evolution or a degradation process? The ground cover in the northern part of the fagne Wallonne bog shows obvious signs of degradation. The southern part of it as well as the fagne de Cléfaye bog show instead an evolution of the vegetation towards a stage heavily composed of heaths, with, however, a strong reduction of peatmosses. The Misten bog seems to experience the slowest evolution: is this a former evolution stage of the vegetation or is the balance achieved? Hydrological studies In natural conditions, the fluctuations of the water table of an ombrotrophic bog on a one-year scale remain modest: about 10 centimetres from one season to the other. It is thus interesting to check if the variations of the water table level are of the same nature in different spots of the three studied bogs or if the alteration phenomena, that are visible at the vegetation level and are present on the three bogs also appear in the behaviour of water tables at the surface of these bogs. Based on the follow-up of the 148 dip wells scattered on the three peat bogs, it appears that the Misten bog water table level is the most stable one. This means that the peat forming species, present on the fagne de Clefaye and especially in the studied part of the fagne Wallonne, are constantly subjected to fluctuations (which are sometimes significant) of the water table level. Now, if the peatmosses usually spread according to a humidity gradient, some of them tolerating a greater distance of the water table level than others, it does not mean however that a same species can survive such variations. The dip wells maps and the 3-dimensional representations of the water table enable to better understand the spreading of the vegetation at the surface of the bog. But these measures also reveal the presence of pedological phenomena, natural or not, such as drainage ditches, outlet, exploitation scar, fissures in the peat mass and others, that very much influence the variation of the water table level and thereby the surface vegetation in the short-, medium-, and long-term Paleo-ecological studies In order to better understand the evolution of raised bogs and especially try to find signs of their degradation, it is essential to investigate the peat lying right under the present vegetation. All the steps that have been set about within this context tried to answer the following questions: Is there a link between the vegetation present at the surface and the recent peat composition lying right under? Is there a link between the recently formed peat composition and the water table level observed on the peat bog? Are the microfossils, that are contained in the peat, affected by variations of the water table? Can we draw differences in the composition of the peat according to how far the boring has been carried out from the current active central zone of the peat bog? It clearly appears that the composition of the peat varies according to the type of present vegetation under which the sample was taken and the range of fluctuations of the water table level recorded on this spot. On the Misten peat bog, the palynological study of peat borings 10 m away from one another allowed to show that peat layers representing the same paleobotanical event(s) do not have the same thickness in each boring and can even be absent. In the same way, at a constant rate of pollen, the accumulation speed of the peat is higher in the bog centre compared to its margins. If one considers a same paleo-botanical event, and thus a same period of time, one can see that the pollen concentration is inversely proportional to the thickness of the peat. Two distinct parts are visible on the borings of the Misten peat bog surface: the upper part, the most recent one, characterised by the influence of the topographic position of the boring on the peat forming speed; the lower part, the oldest one, in which the influence is less pronounced. Thanks to different dating techniques (l4C, pollen concentrations and reference borings), this boundary between the two parts can approximately be dated back to the middle of the 14th century. This phenomenon should be related to an anthropogenic phenomenon rather than to a climatic one, given the short distance separating the borings. It would rather be the result of the manual exploitation of the peat than the harmful effects of the Eupen ditch which was dug much later (1774). A lot of microfossils, identifiable or not, present in the borings (rhizopodes, conidia ...) can doubtless be used as degradation indicators. Of course, these studies need to be deepened and systematised before going any further. What emerges especially from these studies is that when one undertakes regeneration attempts on a peat bog, one should not only take the present vegetation and hydrological parameters into account, but also the peat structure and composition, in at least the upper part of the deposits. Research and management Although acting on the current evolution of the Belgian bogs appears essential in order to prevent them from disappearing, it is clear that restoration measures that were appropriate elsewhere, cannot be applied to other areas without some thorough knowledge of the ecological parameters that govern them. The obvious result of this work is that the scientific follow-up of the management measures that have been taken is not only imperative, but that prior study measures of the sites and their characteristics are indispensable. This type of study is heavy because it requires an important investment from the researcher and often causes a lot of damage to the studied flora and fauna. However, these studies are necessary to understand the peatland systems and should even be complemented by further studies (lysimetric, structural or chemical...) . The standardisation of the data gathering system, the improvement of the information techniques and the management of the results organised in a way that allows all the researchers to consult them should contribute towards some lightening of the work. The computer science and the miniaturised electronic technology could improve the efficiency of the measures implemented, thereby benefiting the researcher and the reserve. Given the implied advanced technologies, these modern studies and data gathering processes would be expensive but it is cheap in comparison to the costs of the heavy works that are to be undertaken in the hope of preserving the raised bogs. Moreover, such a preparation of management measures can only improve their efficiency. If, despite all the efforts, the preservation of the jewels of the state nature reserve of the Haute-Fagnes is jeopardised, these studies will at least allow to go further in the understanding of the raised bogs systems. [less ▲]

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See detailL'Evolution saisonière de la teneur en CO2 de l'air de deux grottes belges : Ste-Anne et Brialmont, Tilff
Gewelt, Michel; Ek, Camille ULg

in Paterson, K.; Sweeting, M.M. (Eds.) New directions in Karst (1983, September)

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See detailThe evolution stages of a local agro-production: The cases of cider and syrup in East Belgium
Schmitz, Serge ULg

in Bryant, Christopher; Grilloti Di Giacomo, Maria (Eds.) Quality Agriculture: Historical Heritage and Environmental Resources for the Integrated Development of Territories (2007)

Relating the history of cider and syrup from the “Pays de Herve” (East of Belgium), the paper underlines the vicissitude of a local production. What remains local in these traditional products? Which ... [more ▼]

Relating the history of cider and syrup from the “Pays de Herve” (East of Belgium), the paper underlines the vicissitude of a local production. What remains local in these traditional products? Which component should remain local in traditional product? [less ▲]

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See detailEvolution sur deux ans des capacités fonctionnelles et motrices de sujets âgés résidant en maison de repos
Buckinx, Fanny ULg; Beaudart, Charlotte ULg; Slomian, Justine ULg et al

in Gériatrie et Psychologie Neuropsychiatrie du Vieillissement (2014), 12(1), 57-58

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