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See detailMéthodes thermiques d'analyse appliquées aux Sciences du Sol et de la Terre
Marcoen, Jean Marie ULg

Conference (1973, November 28)

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See detailA methodological approach to assessing alveolar ridge preservation procedures in humans: soft tissue profile.
VANHOUTTE, Vanessa ULg; ROMPEN, Eric ULg; LECLOUX, Geoffrey ULg et al

in Clinical Oral Implants Research (2013)

Introduction: The aesthetic results of implant restoration in the anterior maxilla are particularly related to the soft tissue profile. Although socket preservation techniques appear to reduce bone ... [more ▼]

Introduction: The aesthetic results of implant restoration in the anterior maxilla are particularly related to the soft tissue profile. Although socket preservation techniques appear to reduce bone remodelling after tooth extraction, there is still few investigations assessing the external soft tissue profile after such procedures. The goal of the present study was to describe an accurate technique to evaluate soft tissue contour changes after performing socket preservation procedures. The secondary objective was to apply the newly develop measuring method to a specific socket preservation using a “saddled” connective tissue graft combined with the insertion of slowly resorbable biomaterials into the socket. Materials and Methods: A total of 14 patients needing tooth replacement in the aesthetic region were included to receive a socket preservation procedure using a connective tissue graft. Impressions were taken before the tooth extraction (baseline) and at 2, 4, and 12 weeks after the procedure. The corresponding plaster casts were scanned, and the evolution of the soft tissue profile in relation to the baseline situation was assessed using imaging software. Results: The measuring technique allowed assessing the soft tissue profiles accurately at different level of the alveolar process. The insertion of a saddled connective tissue appeared to compensate significantly for the horizontal and vertical bone remodelling after a socket preservation procedure in most regions of the alveolar crest. After 12 weeks, the only significant change was located in the more cervical and central region of the alveolar process and reached a mean of 0.76 mm. Conclusion: Within the limitations of this study, we found that a saddled connective tissue graft combined with a socket preservation procedure could almost completely counteract the bone remodelling in terms of the external soft tissue profile. The minor changes found in the cervical region might disappear with the emergence profile of the prosthodontic components. The described technique might therefore enhance the aesthetic outcomes when a tooth has to be replaced in the aesthetic zone. The described protocol can be used to further compare the effectiveness of different extraction socket preservation protocols in randomised controlled trials. [less ▲]

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See detailA methodological approach to assessing alveolar ridge preservation procedures in humans: hard tissue profile.
LAMBERT, France ULg; Vincent, Kim; VANHOUTTE, Vanessa ULg et al

in Journal of Clinical Periodontology (2012), 9

AIMS: Multiple surgical protocols using biomaterials have been proposed to limit the typical post-extraction bone resorption. However, because of the heterogeneity of the studies, particularly the ... [more ▼]

AIMS: Multiple surgical protocols using biomaterials have been proposed to limit the typical post-extraction bone resorption. However, because of the heterogeneity of the studies, particularly the differences in assessment methods, it is difficult to determine the superiority of one technique over another. The objective of this study was to describe a new radiographic method to draw a map of alveolar bone remodelling after alveolar ridge preservation procedures to compare different surgical techniques more accurately. The newly developed measuring method was applied to a case series describing a specific preservation technique. MATERIALS AND METHODS: Fourteen extraction sites (in 14 patients) located in the upper anterior maxilla were treated with bovine hydroxyapatite (0.25- to 1-mm particles) and a saddled connective tissue graft. A radiographic three-dimensional assessment of the hard tissues was performed at baseline and 3 months after the procedure. Standardized horizontal measurements were taken at three corono-apical levels (-2, -5 and -9 mm) and at three mesio-distal levels (mesial, centre and distal) in the buccal and palatal aspects. Vertical measurements were also recorded in nine regions superior to the alveolar crest. The measurements were performed by two independent observers and intra- and inter-observer effects were evaluated. RESULTS: No inter- and intra-observer effects were found when analysing the measurements from these two observers. The horizontal dimension of the crest decreased by 1.6 mm (20%) in the cervical regions (-2 mm level), decreased moderately, by 1 mm (12%), at the -5 mm level and decreased very little, 0.5 mm (6%), at the apical (-8 mm) level. The losses were always significantly higher in the buccal than in the palatal aspect. Buccally, the maximal bone remodelling at the cervical level remained below 1 mm. Vertical bone resorption was homogeneous and<1 mm in the nine measured regions. DISCUSSION: The radiographic measuring methodology proved to be reproducible. It can be applied in other clinical settings. It successfully assessed the alveolar ridge preservation technique (BHA+saddle connective tissue graft). [less ▲]

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See detailA methodological approach towards assessment of land-use and land-cover change.
Bogaert, Jan ULg; Ceulemans, R; Myneni, R b

in Global change open science conference – Challenges of a changing Earth. (2001)

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See detailMethodological approaches to 3D pore structure exploration
Stroeven, Piet; Le, L.B. Nghi; He, Huan ULg

in Key Engineering Materials [=KEM] (2012), 517

About 6% of global CO2 emissions are due to cement production. Blending of Portland cement with a significant fraction of mineral admixture could therefore be instrumental in reducing such emissions. Use ... [more ▼]

About 6% of global CO2 emissions are due to cement production. Blending of Portland cement with a significant fraction of mineral admixture could therefore be instrumental in reducing such emissions. Use of an admixture of vegetable origin such as rice husk as will additionally contribute to waste management and its incineration produces energy. This paper will stress the importance of properly designing such blends. Preferably gap-graded concepts should be employed, since blending efficiency in terms of strength development is promoted as shown in earlier publications. The paper therefore only briefly covers these aspects. Assessment of this blending concept on durability of cementitious materials constitutes a far more complicated problem. This requires careful porosimetry. Mostly, this problem is approached by MIP or by quantitative image analysis. Both can provide 3D information, although that of MIP is generally significantly biased. Quantitative image analysis is however time-consuming and laborious, and thus expensive. Moreover, it does not provide information on continuity of pores. Present day computer facilities offer therefore a better alternative. When using a proper DEM system, the concrete can be simulated in a realistic way. The paper describes new methods for investigating the pore structure in virtual concrete and presents some data on pure cement and blended cement. Differences will have impact on durability risks. [less ▲]

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See detailMethodological bias in home range and mobility estimates when locating radio-tagged trout, Salmo trutta, at different time intervals
Ovidio, Michaël ULg; Philippart, Jean-Claude ULg; Baras, Etienne

in Aquatic Living Resources (2000), 13(6), 449-454

Radio tracking has been extensively used to enhance our knowledge on the movement and home range of fish in general and salmonids in particular. However, the use of various temporal sampling protocols is ... [more ▼]

Radio tracking has been extensively used to enhance our knowledge on the movement and home range of fish in general and salmonids in particular. However, the use of various temporal sampling protocols is likely to overlook fish movements, and produce experimental artefacts, the amplitude of which is unknown and may compromise comparison of fish behaviours revealed by different protocols. Starting from a day-by-day tracking study of brown treat in Belgian waters (Aisne stream, nine fish, minimum 39 daily locations per fish), we re-examined their home range and mobility, through a subsampling process, as if the fish had been located at longer time intervals (2-14 days). The estimates from subsamples were compared to the original data set in order to quantify the corresponding reduction of accuracy from observed data, and how far this could be predicted on the basis of locating frequency. The results clearly indicate that all intervals longer than one day generally generate substantial biases (reduction of accuracy from 0 to 82% for home range and from 5 to 92% for mobility) but these can be partly corrected through the use of predictive models. This analysis demonstrates that any comparison between studies relying on different locating frequencies can generate some ambiguity when interpreting biological phenomena or geographical differences. (C) 2000 Ifremer/CNRS/INRA/IRD/Cemagref/Editions scientifrques et medicales Elsevier SAS. [less ▲]

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See detailMethodological contribution to control heteroscedasticity in discriminant analysis studies.
Glele Kakaï, R.; Palm, Rodolphe ULg

in Global Journal of Pure and Applied Mathematics (2006)

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See detailA methodological evaluation of volumetric measurement techniques including three-dimensional imaging in breast surgery
HOEFFELIN, Harry; JACQUEMIN, Denise ULg; Defaweux, Valérie ULg et al

in BioMed Research International (2014), 2014

Breast surgery currently remains very subjective and each intervention depends on the ability and experience of the operator. To date, no objective measurement of this anatomical region can codify surgery ... [more ▼]

Breast surgery currently remains very subjective and each intervention depends on the ability and experience of the operator. To date, no objective measurement of this anatomical region can codify surgery. In this light, we wanted to compare and validate a new technique for 3D scanning (LifeViz 3D) and its clinical application. Materials and methods. - We tested the use of the 3D LifeViz system (Quantificare) to perform volumetric calculations in various settings ("in situ" in cadaveric dissection, of control prostheses and in clinical patients) and we compared this system to other techniques (CT scanning and Archimedes' principle) under the same conditions. Results. - We were able to identify the benefits (feasibility, safety, portability, low patient stress) and limitations (underestimation of the “in situ” volume, subjectivity of contouring, and patient selection) of the LifeViz 3D system, concluding that the results are comparable with other measurement techniques. Conclusion. - The prospects of this technology seem promising in numerous applications in clinical practice to limit the subjectivity of breast surgery. [less ▲]

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See detailA methodological framework to quantify anthropogenic effects on landscape pattern.
Bogaert, Jan ULg; Barima, Y S S; Ji, J et al

in Hong, S-K; Wu, J; Kim, J-E (Eds.) et al Landscape Ecology in Asian Cultures. Ecological Research Monographs. (2011)

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See detailMethodological Issues in a Cost-of-Dementia Study in Belgium: The National Dementia Economic Study (Nades)
Kurz, Xavier; Broers, Mattie; Scuvée-Moreau, Jacqueline ULg et al

in Acta Neurologica Belgica (1999), 99(3), 167-75

The NAtional Dementia Economic Study (NADES) is an on-going prospective, one-year cohort study developed in Belgium to assess the socio-economic consequences of dementia in a group of patients and their ... [more ▼]

The NAtional Dementia Economic Study (NADES) is an on-going prospective, one-year cohort study developed in Belgium to assess the socio-economic consequences of dementia in a group of patients and their caregivers (n = 400). Comparison is made with a group of subjects with cognitive impairment and no dementia (n = 100) and a group of subjects without any cognitive impairment (n = 100). Recruitment of subjects is based on screening of warning signs of dementia by general practitioners, followed by a Cambridge Mental Disorders of the Elderly Examination (CAMDEX) performed at home. This paper presents an overview of the study protocol and the rationale for basic design options, such as the choice of study population, screening strategy, and methods used for the case validation. It also presents preliminary results on the prevalence of dementia in general practice, the sensitivity and specificity of the warning signs as a screening test of dementia, and the validity of a computerised case ascertainment algorithm based on DSM-III-R criteria. [less ▲]

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See detailMethodological issues in primary prevention trials for neurodegenerative dementia.
Andrieu, Sandrine; Coley, Nicola; Aisen, Paul et al

in Journal of Alzheimer's Disease [=JAD] (2009), 16(2), 235-70

The prevention of neurodegenerative dementias, such as Alzheimer's disease, is a public health priority. Due to the large numbers of affected patients, even interventions bringing about a relatively small ... [more ▼]

The prevention of neurodegenerative dementias, such as Alzheimer's disease, is a public health priority. Due to the large numbers of affected patients, even interventions bringing about a relatively small delay in disease onset could have large public health effects. Randomized controlled trials (RCTs) are required to demonstrate the effectiveness of preventive interventions, but such trials raise specific methodological questions because they are new in the field of neurodegenerative diseases, and require large numbers of elderly subjects and lengthy follow-up periods. We performed a literature search to identify primary prevention RCTs for neurodegenerative dementia. The methodology of the trials was summarized and discussed during two expert meetings. Overall, 39 trials were identified that assessed dementia incidence or cognitive decline as a primary or secondary study outcome. Age was the most common selection criteria for target populations. Follow-up periods ranged from one month to nine years and were longest in studies measuring dementia incidence as an outcome. Results of RCTs have so far been generally negative and conflicting with those of observational studies, perhaps due to methodological issues. Future trials must therefore carefully consider the target population, outcomes and duration of follow-up to be used, and should assess the problem of attrition. [less ▲]

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See detailthe methodological stakes of gender approach
Gavray, Claire ULg

Conference given outside the academic context (2009)

my way of integrating 'gender' in my research .

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See detailThe methodological stakes of gender approach
Gavray, Claire ULg

Conference (2009, June 12)

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See detailMéthodologie d’acquisition d’une collection d’échantillons de sols liés aux matériaux parentaux en Wallonie
Legrain, Xavier ULg; Renneson, Malorie ULg; Genot, Valérie ULg et al

Poster (2010, November 24)

Malgré l'exiguïté de son territoire, la Wallonie est dotée d’un contexte géologique particulièrement varié et contrasté. Des grandes géostructures aux formations lithostratigraphiques, cette diversité se ... [more ▼]

Malgré l'exiguïté de son territoire, la Wallonie est dotée d’un contexte géologique particulièrement varié et contrasté. Des grandes géostructures aux formations lithostratigraphiques, cette diversité se reflète au niveau des situations pédologiques rencontrées. En effet, l’altération des roches, à l’origine du matériau parental, constitue un des processus majeurs indispensables à la formation d’un sol. Par ailleurs, à travers sa nature et sa composition, ce matériau d’origine est reconnu comme un des facteurs prépondérants influençant la pédogenèse, et de ce fait, les propriétés des sols. Fort de ce constat, l’Unité de Science du Sol de Gembloux Agro-Bio Tech, à travers la collaboration de divers projets, a entrepris la collecte d’échantillons de sols, en relation avec les matériaux parentaux à l’origine de la majorité des sols présents en Wallonie. L’objectif poursuivi est (i) d’acquérir des données à caractère « permanent », intrinsèques à ces matériaux parentaux, afin d’en dégager une signature chimique, physico-chimique, physique et spectrale, et (ii) de mettre en évidence l’influence tant du matériau parental que de l’occupation du sol sur les propriétés des horizons de surface. L’originalité du travail réside en partie dans la stratégie d’échantillonnage, basée sur une stratification pédologique et géographique, par la prise en compte respectivement de la Carte des Principaux Types de Sols de Wallonie et des Unités de l’Espace Rural. Les choix opérés ont conduit à la sélection de 12 matériaux parentaux, chacun faisant l’objet de prélèvements en 10 points (surface et profondeur). La localisation précise de ces points a été déterminée sur base d’une analyse et de la confrontation de documents cartographiques existants, se rapportant essentiellement aux sigles pédologiques, aux formations lithostratigraphiques, au relief et à l’occupation des sols. Un total de 258 échantillons a ainsi été prélevé en 120 points (76 en culture, 15 en prairie temporaire et 29 en prairie permanente). Parmi les analyses déjà réalisées citons, outre le menu d’analyse classique en pédologie (pH H2O et KCl, carbonates, granulométrie, COT, CEC, …), la détermination des formes du phosphore (total, minéral, organique ou disponible), des teneurs totales en éléments traces métalliques, la mesure de paramètres physiques ou hydriques tels que les limites d’Atterberg ou les courbes pF, ainsi que diverses analyses par spectroscopie proche infrarouge. Parmi les mesures envisagées à l’avenir, citons des analyses minéralogiques et des mesures de stabilité structurale. [less ▲]

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See detailMéthodologie d'évaluation énergétique des quartiers périurbains. Perspectives pour le renouvellement périurbain wallon.
Marique, Anne-Françoise ULg

Doctoral thesis (2013)

The process of urban sprawl, which commonly describes physically expanding urban areas, is a major issue for sustainable development. Urban sprawl is known to represent a significant contribution to the ... [more ▼]

The process of urban sprawl, which commonly describes physically expanding urban areas, is a major issue for sustainable development. Urban sprawl is known to represent a significant contribution to the overall energy consumption of a territory for energy needs in buildings and for transportation. In this context, the thesis focuses on the energy assessment of existing suburban neighborhoods. The assessment includes two parts: (1) a computational approach combining dynamic simulation tools and a database of building typologies to determine the energy consumed in heating and (2) an empirical approach to assess the energy consumed by transportation systems (home-to-work and home-to-school journeys). The links between the spatial structure of the territory and energy use for commuting are highlighted. Several renewal strategies are proposed to improve energy efficiency in existing suburban neighborhoods. There investigate the thermal retrofitting of existing neighborhoods, the built density and demolition/reconstruction processes together with the location of the neighborhoods. Urban structure acts upon travel energy consumption for commuting. A good mix between work, schools and dwellings at the local scale, which allows reduced travel distances, is a good strategy to reduce transport energy consumption, whereas means of transport used is only of little impact. Student travel behaviors are specific to the level of education and the type of neighborhood. Finally, the thesis discusses the practical implications of the research to operationalize a suburban renewal that articulates energy efficiency of buildings and neighborhoods but also energy efficiency of the urban structure. [less ▲]

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