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Thomas I.,U.C.L | Thomas I.,National Fund for Scientific Research FRS FNRS | Frankhauser P.,University of Franche Comte | Badariotti D.,University of Strasbourg
Journal of Geographical Systems | Year: 2012

The objective of this paper is to show that morphological similarities between built-up urban surfaces are greater across borders than within cities in Europe: living, architectural and planning trends are international. The spatial arrangement of built-up areas is analysed here by means of fractal indices using a set of 97 town sections selected from 18 European urban agglomerations. The fractal dimension is estimated by correlation techniques. Results confirm that morphological similarities are higher across countries/cities than within. Moreover, two types of fractal laws are considered: one uses the basic fractal scaling law; the other introduces a prefactor a that is often called a "form factor" in the fractal literature. Differences in the results obtained by both laws are explained empirically as well as theoretically, and suggestions are made for further measurements. © 2010 Springer-Verlag.


Collette F.,University of Liège | Collette F.,National Fund for Scientific Research FRS FNRS | Van Der Linden M.,University of Liège | Van Der Linden M.,University of Geneva | And 2 more authors.
Journal of Alzheimer's Disease | Year: 2010

A decline of cognitive functioning affecting several cognitive domains was frequently reported in patients with frontotemporal dementia. We were interested in determining if these deficits can be interpreted as reflecting an impairment of controlled cognitive processes by using an assessment tool specifically developed to explore the distinction between automatic and controlled processes, namely the process dissociation procedure (PDP) developed by Jacoby [1]. The PDP was applied to a word stem completion task to determine the contribution of automatic and controlled processes to episodic memory performance and was administered to a group of 12 patients with the behavioral variant of frontotemporal dementia (bv-FTD) and 20 control subjects (CS). Bv-FTD patients obtained a lower performance than CS for the estimates of controlled processes, but no group differences was observed for estimates of automatic processes. The between-groups comparison of the estimates of controlled and automatic processes showed a larger contribution of automatic processes to performance in bv-FTD, while a slightly more important contribution of controlled processes was observed in control subjects. These results are clearly indicative of an alteration of controlled memory processes in bv-FTD. © 2010 IOS Press and the authors. All rights reserved.


Weytens F.,Catholic University of Louvain | Weytens F.,National Fund for Scientific Research FRS FNRS | Luminet O.,Catholic University of Louvain | Luminet O.,National Fund for Scientific Research FRS FNRS | And 2 more authors.
PLoS ONE | Year: 2014

Over the past fifteen years, positive psychology research has validated a set of happiness enhancing techniques. These techniques are relatively simple exercises that allow happiness seekers to mimic thoughts and behavior of naturally happy people, in order to increase their level of well-being. Because research has shown that the joint use of these exercises increases their effects, practitioners who want to help happiness seekers need validated interventions that combine several of these techniques. To meet this need, we have developed and tested an integrative intervention (Positive Emotion Regulation program - PER program) incorporating a number of validated techniques structured around a theoretical model: the Process Model of Positive Emotion Regulation. To test the effectiveness of this program and to identify its added value relative to existing interventions, 113 undergraduate students were randomly assigned to a 6-week positive emotion regulation pilot program, a loving-kindness meditation training program, or a wait-list control group. Results indicate that fewer participants dropped out from the PER program than from the Loving-Kindness Meditation training. Furthermore, subjects in the PER group showed a significant increase in subjective well-being and life satisfaction and a significant decrease in depression and physical symptoms when compared to controls. Our results suggest that the Process Model of Positive Emotion Regulation can be an effective option to organize and deliver positive integrative interventions. © 2014 Weytens et al.


Chang B.,Catholic University of Louvain | Vermeulen N.,Catholic University of Louvain | Vermeulen N.,National Fund for Scientific Research FRS FNRS
Behavioral and Brain Sciences | Year: 2010

We argue that the meaning of smiles is interpreted from physical/contextual cues, and simulation may simply reinforce the information derived from these cues. We suggest that, contrary to the claim of the SIMS model, positive and negative smiles may invoke similar simulation processes. Finally, we provide alternative explanations for the role of eye contact in the processing of smiles. © 2010 Cambridge University Press.


Bastin C.,University of Liège | Berry D.P.,Teagasc | Soyeurt H.,University of Liège | Soyeurt H.,National Fund For Scientific Research Frs Fnrs | Gengler N.,University of Liège
Journal of Dairy Science | Year: 2012

The objective of this study was to estimate the genetic relationships between days open (DO) and both milk production traits and fatty acid (FA) content in milk predicted by mid-infrared spectrometry. The edited data set included 143,332 FA and production test-day records and 29,792 DO records from 29,792 cows in 1,170 herds. (Co)variances were estimated using a series of 2-trait models that included a random regression for milk production and FA traits. In contrast to the genetic correlations with fat content, those between DO and FA content in milk changed considerably over the lactation. The genetic correlations with DO for unsaturated FA, monounsaturated FA, long-chain FA, C18:0, and C18:1 cis-9 were positive in early lactation but negative after 100 d in milk. For the other FA, genetic correlations with DO were negative across the whole lactation. At 5 d in milk, the genetic correlation between DO and C18:1 cis-9 was 0.39, whereas the genetic correlations between DO and C6:0 to C16:0 FA ranged from -0.37 to -0.23. These results substantiated the known relationship between fertility and energy balance status, explained by the release of long-chain FA in early lactation, from the mobilization of body fat reserves, and the consequent inhibition of de novo FA synthesis in the mammary gland. At 200 d in milk, the genetic correlations between DO and FA content ranged from -0.38 for C18:1 cis-9 to -0.03 for C6:0. This research indicates an opportunity to use FA content in milk as an indicator trait to supplement the prediction of genetic merit for fertility. © 2012 American Dairy Science Association.


Bastin C.,University of Liège | Soyeurt H.,University of Liège | Soyeurt H.,National Fund For Scientific Research Frs Fnrs | Gengler N.,University of Liège
Journal of Animal Breeding and Genetics | Year: 2013

Summary: The objective of this study was to estimate genetic parameters of milk, fat, and protein yields, fat and protein contents, somatic cell count, and 17 groups and individual milk fatty acid (FA) contents predicted by mid-infrared spectrometry for first-, second- and third-parity Holstein cows. Edited data included records collected in the Walloon region of Belgium from 37 768 cows in parity 1, 22 566 cows in parity 2 and 8221 in parity 3. A total of 69 (23 traits for three parities) single-trait random regression animal test-day models were run. Approximate genetic correlations among traits were inferred from pairwise regressions among estimated breeding values of cow having observations. Heritability and genetic correlation estimates from this study reflected the origins of FA: de novo synthetized or originating from the diet and the body fat mobilization. Averaged daily heritabilities of FA contents in milk ranged between 0.18 and 0.47. Average daily genetic correlations (averaged across days in milk and parities) among groups and individual FA contents in milk ranged between 0.31 and 0.99. The genetic variability of FAs in combination with the moderate to high heritabilities indicated that FA contents in milk could be changed by genetic selection; however, desirable direction of change in these traits remains unclear and should be defined with respect to all issues of importance related to milk FA. © 2012 Blackwell Verlag GmbH.


Vandenbulcke G.,Catholic University of Louvain | Thomas I.,Catholic University of Louvain | Thomas I.,National Fund for Scientific Research FRS FNRS | Int Panis L.,Flemish Institute for Technological Research | Int Panis L.,Hasselt University
Accident Analysis and Prevention | Year: 2014

This paper aims at predicting cycling accident risk for an entire network and identifying how road infrastructure influences cycling safety in the Brussels-Capital Region (Belgium). A spatial Bayesian modelling approach is proposed using a binary dependent variable (accident, no accident at location i) constructed from a case-control strategy. Control sites are sampled along the 'bikeable' road network in function of the potential bicycle traffic transiting in each ward. Risk factors are limited to infrastructure, traffic and environmental characteristics. Results suggest that a high risk is statistically associated with the presence of on-road tram tracks, bridges without cycling facility, complex intersections, proximity to shopping centres or garages, and busy van and truck traffic. Cycle facilities built at intersections and parked vehicles located next to separated cycle facilities are also associated with an increased risk, whereas contraflow cycling is associated with a reduced risk. The cycling accident risk is far from being negligible in points where there is actually no reported cycling accident but where they are yet expected to occur. Hence, mapping predicted accident risks provides planners and policy makers with a useful tool for accurately locating places with a high potential risk even before accidents actually happen. This also provides comprehensible information for orienting cyclists to the safest routes in Brussels. © 2013 Elsevier Ltd. All rights reserved.


Bastin C.,University of Liège | Gengler N.,University of Liège | Gengler N.,National Fund For Scientific Research Frs Fnrs | Soyeurt H.,University of Liège | Soyeurt H.,National Fund For Scientific Research Frs Fnrs
Journal of Dairy Science | Year: 2011

The objective of this study was to assess the phenotypic and genetic variability of production traits and milk fatty acid (FA) contents throughout lactation. Genetic parameters for milk, fat, and protein yields, fat and protein contents, and 19 groups and individual FA contents in milk were estimated for first-parity Holstein cows in the Walloon Region of Belgium using single-trait, test-day animal models and random regressions. Data included 130,285 records from 26,166 cows in 531 herds. Heritabilities indicated that de novo synthesized FA were under stronger genetic control than FA originating from the diet and from body fat mobilization. Estimates for saturated short- and medium-chain individual FA ranged from 0.35 for C4:0 to 0.44 for C8:0, whereas those for monounsaturated long-chain individual FA were lower (around 0.18). Moreover, de novo synthesized FA were more heritable in mid to late lactation. Approximate daily genetic correlations among traits were calculated as correlations between daily breeding values for days in milk between 5 and 305. Averaged daily genetic correlations between milk yield and FA contents did not vary strongly among FA (around -0.35) but they varied strongly across days in milk, especially in early lactation. Results indicate that cows selected for high milk yield in early lactation would have lower de novo synthesized FA contents in milk but a slightly higher content of C18:1 cis-9, indicating that such cows might mobilize body fat reserves. Genetic correlations among FA emphasized the combination of FA according to their origin: contents in milk of de novo FA were highly correlated with each other (from 0.64 to 0.99). Results also showed that genetic correlations between C18:1 cis-9 and other FA varied strongly during the first 100 d in milk and reinforced the statement that the release of long-chain FA inhibits FA synthesis in the mammary gland while the cow is in negative energy balance. Finally, results showed that the FA profile in milk changed during the lactation phenotypically and genetically, emphasizing the relationship between the physiological status of cow and milk composition. © 2011 American Dairy Science Association.


Debue N.,Free University of Colombia | Debue N.,National Fund for Scientific Research FRS FNRS | van de Leemput C.,Free University of Colombia
Frontiers in Psychology | Year: 2014

While over the last decades, much attention has been paid to the mental workload in the field of human computer interactions, there is still a lack of consensus concerning the factors that generate it as well as the measurement methods that could reflect workload variations. Based on the multifactorial Cognitive Load Theory, our study aims to provide some food for thought about the subjective and objective measurement that can be used to disentangle the intrinsic, extraneous and germane load. The purpose is to provide insight into the way cognitive load can explain how users' cognitive resources are allocated in the use of hypermedia, such as an online newspaper. A two-phase experiment has been conducted on the information retention from online news stories. Phase 1 (92 participants) examined the influence of multimedia content on performance as well as the relationships between cognitive loads and cognitive absorption. In Phase 2 (36 participants), eye23 tracking data were collected in order to provide reliable and objective measures. Results confirmed that performance in information retention was impacted by the presence of multimedia content such as animations and pictures. The higher number of fixations on these animations suggests that users' attention could have been attracted by them. Results showed the expected opposite relationships between Germane and Extraneous Load, a positive association between GL and cognitive absorption and a nonlinear association between Intrinsic and Germane Load. The trends based on eye-tracking data analysis provide some interesting findings about the relationship between longer fixations, shorter saccades and cognitive load. Some issues are raised about the respective contribution of mean pupil diameter and Index of Cognitive Activity. © 2014 Debue and Van_de_leemput.


Vandenbulcke G.,Catholic University of Louvain | Dujardin C.,Catholic University of Louvain | Dujardin C.,National Fund for Scientific Research FRS FNRS | Thomas I.,Catholic University of Louvain | And 6 more authors.
Transportation Research Part A: Policy and Practice | Year: 2011

This paper attempts to explain the spatial variation of the use of a bicycle for commuting to work at the level of the 589 municipalities in Belgium. Regression techniques were used and special attention was paid to autocorrelation, heterogeneity and multicollinearity. Spatial lag models were used to correct for the presence of spatial dependence and a disaggregated modelling strategy was adopted for the northern and southern parts of the country. The results show that much of the inter-municipality variation in bicycle use is related to environmental aspects such as the relief, traffic volumes and cycling accidents. Town size, distance travelled and demographic aspects also have some effect. In addition, there are regional differences in the effects of the structural covariates on bicycle use: the impact of variables such as traffic volume and cycling accidents differs substantially between the north and the south of the country. This paper also suggests that high rates of bicycle use in one municipality stimulate cycling in neighbouring municipalities, and hence that a mass effect can be initiated, i.e. more cycle commuting encourages even more commuters in the area to cycle. These findings provide some recommendations for decision-makers wishing to promote a shift from car to bicycle use. © 2010 Elsevier Ltd.

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