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See detailHeterochrony in a complex world: disentangling environmental processes of facultative paedomorphosis in an amphibian
Denoël, Mathieu ULg; Ficetola, Gentile Francesco

in Journal of Animal Ecology (2014), 83(3), 606-615

1. Heterochrony, the change in the rate or timing of development between ancestors and their descendants, plays a major role in evolution. When heterochrony produces polymorphisms, it offers the ... [more ▼]

1. Heterochrony, the change in the rate or timing of development between ancestors and their descendants, plays a major role in evolution. When heterochrony produces polymorphisms, it offers the possibility to test hypotheses that could explain its success across environments. Amphibians are particularly suitable to exploring these questions because they express complex life cycles (i.e. metamorphosis) that have been disrupted by heterochronic processes (paedomorphosis: retention of larval traits in adults). The large phenotypic variation across populations suggests that more complex processes than expected are operating, but they remain to be investigated through multivariate analyses over a large range of natural populations across time. 2. In this study we compared the likelihood of multiple potential environmental determinants of heterochrony. We gathered data on the proportion of paedomorphic and metamorphic palmate newts (Lissotriton helveticus) across more than 150 populations during 10 years, and used an information-theoretic approach to compare the support of multiple potential processes. 3. Six environmental processes jointly explained the proportion of paedomorphs in populations: predation, water availability, dispersal limitation, aquatic breathing, terrestrial habitat suitability, and anti-predator refuges. Analyses of variation across space and time supported models based on the advantage of paedomorphosis in favourable aquatic habitats. 4. Paedomorphs were favoured in deep ponds, in conditions favourable to aquatic breathing (high oxygen content), with lack of fish, and surrounded by suitable terrestrial habitat. Metamorphs were favoured by banks allowing easy dispersal. 5. These results indicate that heterochrony relies on complex processes involving multiple ecological variables and exemplifies why heterochronic patterns occur in contrasted environments. On the other hand, the fast selection of alternative morphs shows that metamorphosis and paedomorphosis developmental modes could be easily disrupted in natural populations. [less ▲]

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See detailL'hétérogénéité de l'insuline cristalline
Fredericq, Léon ULg

in Archives Internationales de Physiologie (1953)

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See detailHétérogénéité des échelles spatio-temporelles d'écoulements hydrosédimentaires et modélisation numérique
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Houille Blanche (2008), (5), 109-114

Les modèles numériques hydrosédimentaires doivent être aptes à prendre en compte la très grande hétérogénéité des échelles spatiales et surtout temporelles affectant les divers phénomènes à simuler. Pour ... [more ▼]

Les modèles numériques hydrosédimentaires doivent être aptes à prendre en compte la très grande hétérogénéité des échelles spatiales et surtout temporelles affectant les divers phénomènes à simuler. Pour ce faire, différents niveaux de couplage entre sous-modèles doivent être prévus (calcul hydrodynamique stationnaire, quasi stationnaire ou instationnaire complet). Outre une discussion du formalisme mathématique sous-jacent, la présente communication décrit le système de modélisation WOLF, développé à l’Université de Liège et permettant de couvrir la majorité des échelles de temps pertinentes au moyen d’approches numériques spécifiquement adaptées. L’applicabilité du système de modélisation est illustrée sur base de plusieurs exemples de simulations relatives à la conception et aux modes de gestion d’un grand ouvrage hydroélectrique en Inde. [less ▲]

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See detailHétérogénéité des échelles spatio-temporelles d’écoulements hydrosédimentaires et modélisation numérique
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Articles du colloque Transports solides et gestion des sédiments en milieux naturels et urbains (2007)

The numerical models for flow and sediment transport must be able to handle properly the wide range of space- and time-scales relevant for the processes to be modelled. For this purpose different levels ... [more ▼]

The numerical models for flow and sediment transport must be able to handle properly the wide range of space- and time-scales relevant for the processes to be modelled. For this purpose different levels of numerical coupling between the flow solver and the sediment transport model must be considered. Besides a short review of the mathematical background, the present paper describes the modelling system WOLF, developed at the University of Liege and enabling to handle the vast majority of time scales characterizing practical applications of flows with sediment transport, by means of specific numerical techniques. The applicability of the modelling system is demonstrated based on several examples of simulations related to the design and the operation of a large hydroelectric project in India. [less ▲]

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See detailHétérogénéité, mon cher souci
Lafontaine, Dominique ULg

in Revue Internationale d'Education (2005), 40

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See detailHétérogénéité, mon cher souci
Lafontaine, Dominique ULg

(2005, April)

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See detailHeterogeneity of (co)variance components for Jersey type traits
Gengler, Nicolas ULg; Dusseldorf, T.; Wiggans, G. R. et al

in Journal of Dairy Science (2001), 84

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See detailHeterogeneity of brain glucose metabolism in mild cognitive impairment and clinical progression to Alzheimer disease
Anchisi, D.; Borroni, B.; Franceschi, M. et al

in Archives of Neurology (2005), 62(11), 1728-1733

Background: Subjects with amnesic mild cognitive impairment (aMCI) may include patients at high risk for progression to Alzheimer disease (AD) and a population with different underlying pathologic ... [more ▼]

Background: Subjects with amnesic mild cognitive impairment (aMCI) may include patients at high risk for progression to Alzheimer disease (AD) and a population with different underlying pathologic conditions. Objective: To evaluate the potential roles of positron emission tomography with fluodeoxyglucose F 18 ((18)FDG-PET) and memory scores in identifying subjects with aMCI and in predicting progression to dementia. Design, Setting, and Patients: Sixty-seven patients at European centers for neurologic and AD care who were diagnosed as having aMCI each underwent an extensive clinical and neuropsychological examination and an (18)FDG-PET study. Forty-eight subjects were followed up periodically for at least I year, and progression to dementia was evaluated. Main Outcome Measures: Brain glucose metabolism and memory scores. Results: Fourteen subjects with aMCI who converted to AD within 1 year showed bilateral hypometabolism in the inferior parietal, posterior cingulate, and medial temporal cortex. Subjects with "stable" aMCI presented with hypometabolism in the dorsolateral frontal cortex. The severity of memory impairment, as evaluated by the California Verbal Learning Test-Long Delay Free Recall scores, correlated with the following brain metabolic patterns: scores less than 7 were associated with a typical (18)FDG-PET AD pattern, and scores of 7 or higher were associated with hypornetabolism in the dorsolateral frontal cortex and no progression to AD. Conclusion: These data provide evidence for clinical and functional heterogeneity among subjects with aMCI and suggest that (18)FDG-PET findings combined with memory scores may be useful in predicting short-term conversion to AD. [less ▲]

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See detailHeterogeneity of follow-up procedures in French and Belgian patients with treated hereditary tyrosinemia type 1: results of a questionnaire and proposed guidelines.
Schiff, Manuel; Broue, Pierre; Chabrol, Brigitte et al

in Journal of inherited metabolic disease (2012), 35(5), 823-9

The 1991 introduction of 2-(2-nitro-4-trifluoro-methylbenzyol)-1,3 cyclohexanedione (NTBC) as a treatment for hereditary tyrosinemia type 1 (HT-1), a disorder of tyrosine catabolism, has radically ... [more ▼]

The 1991 introduction of 2-(2-nitro-4-trifluoro-methylbenzyol)-1,3 cyclohexanedione (NTBC) as a treatment for hereditary tyrosinemia type 1 (HT-1), a disorder of tyrosine catabolism, has radically modified the natural history of this disorder. Despite the dramatic improvements in survival, outcomes and quality of life seen with NTBC treatment, HT-1 remains a chronic disorder with several long-term complications, including, a persistent (albeit low) risk of hepatocellular carcinoma and suboptimal neuropsychological outcomes. There remain unsolved key-questions concerning the long-term outcomes of patients with HT-1, which closely depend on the quality of follow-up in these patients. In the absence of published guidelines, we investigated the follow-up methods used for French and Belgian patients with HT-1. A simple questionnaire providing a rapid overview of follow-up procedures was sent to the 19 physicians in charge of HT-1 patients treated with NTBC and low-tyrosine diet in France and Belgium. Several areas of heterogeneity (especially liver imaging, slit lamp examination, neuropsychological evaluation and maximal plasma tyrosine level accepted) were observed. In an attempt to improve long-term management and outcome of patients with HT-1, we proposed follow-up recommendations. [less ▲]

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See detailHeterogeneity of multitasking abilities in schizophrenia.
Laloyaux, Julien ULg; Van der Linden, Martial ULg; Laroi, Frank ULg

Conference (2015, May 28)

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to ... [more ▼]

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to activities (e.g. preparing a meal) where the person has to: (a) carry out and alternate between different tasks that vary in terms of priority, difficulty and duration; (b) define the tasks’ targets; (c) and face unexpected problems during the realization of these tasks. Moreover, schizophrenia is characterized by a great heterogeneity in regard to their everyday life difficulties and cognitive functioning. At present, patients’ multitasking capacities have not been adequately examined in the literature due to an absence of suitable assessment strategies. We thus recently developed a computerized real-life activity task designed to take into account the complex and multitasking nature of certain everyday life activities where participants are required to prepare a room for a meeting (i.e. the Computerized Meeting Preparation Task, CMPT). The aim of this study was to examine the multitasking abilities in persons diagnosed with schizophrenia and in particular the existence of subgroups of patients in regard to their performances on cognitive measures and on the CMPT. Sixty-two patients diagnosed with schizophrenia and 39 paired healthy controls completed the CMPT and a cognitive battery. The results reveal that the CMPT possesses good sensitivity and suggest three underlying constructs of multitasking (Memory, Planning and Intent), which were found to be underpinned by several cognitive functions and multitasking aspects. Moreover, cluster analyses revealed subgroups of patients differing in terms of their cognitive and CMPT performances. Taken together, these results show the need for a cognitive model of multitasking abilities in persons diagnosed with schiozphrenia. Taken together, this cognitive model and the CMPT, could be a good basis for cognitive interventions of multitasking abilities in schizophrenia. Finally, the results underline the heterogeneity of schizophrenia. [less ▲]

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See detailHeterogeneity of multitasking abilities in schizophrenia.
Laloyaux, Julien ULg; Van der Linden, Martial ULg; Laroi, Frank ULg

in Van Overwalle, Frank; Uzieblo, Kasia; Rossi, Gina (Eds.) et al Abstract book of the Annual meeting of the Belgian Association for Psychological Sciences (2015)

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to ... [more ▼]

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to activities (e.g. preparing a meal) where the person has to: (a) carry out and alternate between different tasks that vary in terms of priority, difficulty and duration; (b) define the tasks’ targets; (c) and face unexpected problems during the realization of these tasks. Moreover, schizophrenia is characterized by a great heterogeneity in regard to their everyday life difficulties and cognitive functioning. At present, patients’ multitasking capacities have not been adequately examined in the literature due to an absence of suitable assessment strategies. We thus recently developed a computerized real-life activity task designed to take into account the complex and multitasking nature of certain everyday life activities where participants are required to prepare a room for a meeting (i.e. the Computerized Meeting Preparation Task, CMPT). The aim of this study was to examine the multitasking abilities in persons diagnosed with schizophrenia and in particular the existence of subgroups of patients in regard to their performances on cognitive measures and on the CMPT. Sixty-two patients diagnosed with schizophrenia and 39 paired healthy controls completed the CMPT and a cognitive battery. The results reveal that the CMPT possesses good sensitivity and suggest three underlying constructs of multitasking (Memory, Planning and Intent), which were found to be underpinned by several cognitive functions and multitasking aspects. Moreover, cluster analyses revealed subgroups of patients differing in terms of their cognitive and CMPT performances. Taken together, these results show the need for a cognitive model of multitasking abilities in persons diagnosed with schiozphrenia. Taken together, this cognitive model and the CMPT, could be a good basis for cognitive interventions of multitasking abilities in schizophrenia. Finally, the results underline the heterogeneity of schizophrenia. [less ▲]

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See detailHeterogeneity of phenotypes in severe asthmatics. The Belgian Severe Asthma Registry (BSAR).
SCHLEICH, FLorence ULg; Brusselle, G.; Louis, Renaud ULg et al

in Respiratory medicine (2014), 108(12), 1723-32

The Belgian severe asthma registry is a web-based registry encompassing demographic, clinical, functional and inflammatory data of severe asthmatics (SA), aiming at improving awareness, knowledge on its ... [more ▼]

The Belgian severe asthma registry is a web-based registry encompassing demographic, clinical, functional and inflammatory data of severe asthmatics (SA), aiming at improving awareness, knowledge on its natural history and subphenotypes, and offering tools to optimize care of this asthma population. METHODS: The cross-sectional analyses of this registry included 350 SA as defined by the ATS (2000) from 9 Belgian centres, with at least one year follow up. RESULTS: Mean age was 55 +/- 14 yrs. SA were more frequently female (57%) and atopic (70%). Late-onset asthma (>/=40 yr) was observed in 31% of SA. Current smokers represented 12% while 31% were ex-smokers. In addition to high doses ICS + LABA, 65% of patients were receiving LTRA, 27% anti-IgE and 24% maintenance oral corticosteroids (8 mg (Interquartile range-IQR:4-8) methylprednisolone). Despite impaired airflow (median FEV1:67%; IQR: 52-81) only 65% had a post-bronchodilator FEV1/FVC ratio <70%. The median blood eosinophil count was 240/mm(3). The median FENO was 26 ppb (IQR: 15-43) and 22% of SA had FENO >/= 50 ppb. Induced sputum was successful in 86 patients. Eosinophilic asthma (sputum Eos >/= 3%) was the predominant phenotype (55%) while neutrophilic (sputum Neu >/= 76%) and paucigranulocytic asthma accounted for 22% and 17% respectively. Comorbidities included rhinitis and chronic rhinosinusitis (49%), nasal polyposis (19%), oesophageal reflux (36%), overweight and obesity (47%) and depression (19%). In addition, 8% had aspirin-induced asthma and 3% ABPA. Asthma was not well-controlled in 83% according to ACT < 20 and 77% with ACQ > 1.5. CONCLUSION: In this cohort of patients with severe asthma, the majority displayed indices of persistent airflow limitation and eosinophilic inflammation despite high-dose corticosteroids, suggesting potential for eosinophil-targeted biotherapies. [less ▲]

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See detailHeterogeneity of residuals variances of milk fatty acids in dairy cattle
Arnould, Valérie ULg; Soyeurt, Hélène ULg; Vanderick, Sylvie ULg et al

in Journal of Dairy Science (2010, July), 88(E-Suppl. 2), 744

Routine genetic evaluation for milk fatty acids is under development in the Walloon Region of Belgium. The objective of this study was to test the heterogeneity of residual variances and therefore ... [more ▼]

Routine genetic evaluation for milk fatty acids is under development in the Walloon Region of Belgium. The objective of this study was to test the heterogeneity of residual variances and therefore indirectly the potential need to adjust for this heterogeneity if it exists. The residuals were computed as the difference between the observed and the estimated values using a multi-trait random regression test-day model, similar to the Walloon routine model, used for first lactation only milk yield, quantities and percentages of protein (PROT) and fat (FAT), content of saturated fatty acids in milk (g/100g of milk, SAT) and, content of mono-unsaturated fatty acids in milk (g/100g of milk, MONO). Residuals were considered homogeneous inside strata defined, among others, by weeks of lactation, by days in milk and by calendar months of test date. About 6,687,000 records were available for milk yield and for FAT and PROT parameters. For SAT and for MONO, about 184,000 records were available in this database. Means of residuals were stable and close to zero for all traits. Variances were more variable for MONO and SAT than for milk yield, for example. Daily and weekly variances tended to decrease at the end of the lactation (50%). When the variances were computed by month of test date, some variations were observed and some periods of year were more marked. In conclusion, the observed residual variances were less stable for MONO and SAT. We can conclude that introduction for heterogeneous residual variance is more important for the new traits (MONO, SAT) than it was for the old, traditional ones. [less ▲]

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See detailHeterogeneity of residuals variances of milk fatty acids in dairy cattle
Arnould, Valérie ULg; Soyeurt, Hélène ULg; Vanderick, Sylvie ULg et al

Conference (2010, July)

Routine genetic evaluation for milk fatty acids is under development in the Walloon Region of Belgium. The objective of this study was to test the heterogeneity of residual variances and therefore ... [more ▼]

Routine genetic evaluation for milk fatty acids is under development in the Walloon Region of Belgium. The objective of this study was to test the heterogeneity of residual variances and therefore indirectly the potential need to adjust for this heterogeneity if it exists. The residuals were computed as the difference between the observed and the estimated values using a multi-trait random regression test-day model, similar to the Walloon routine model, used for first lactation only milk yield, quantities and percentages of protein (PROT) and fat (FAT), content of saturated fatty acids in milk (g/100g of milk, SAT) and, content of mono-unsaturated fatty acids in milk (g/100g of milk, MONO). Residuals were considered homogeneous inside strata defined, among others, by weeks of lactation, by days in milk and by calendar months of test date. About 6,687,000 records were available for milk yield and for FAT and PROT parameters. For SAT and for MONO, about 184,000 records were available in this database. Means of residuals were stable and close to zero for all traits. Variances were more variable for MONO and SAT than for milk yield, for example. Daily and weekly variances tended to decrease at the end of the lactation (50%). When the variances were computed by month of test date, some variations were observed and some periods of year were more marked. In conclusion, the observed residual variances were less stable for MONO and SAT. We can conclude that introduction for heterogeneous residual variance is more important for the new traits (MONO, SAT) than it was for the old, traditional ones. [less ▲]

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See detailHeterogeneity of sponastrime dysplasia: Delineation of a variant form with severe mental retardation
Verloes, Alain ULg; Misson, Jean-Paul ULg; Dubru, J. M. et al

in Clinical Dysmorphology (1995), 4(3), 208-215

We report a child with short stature, osteopenia with metaphyseal striations and severe mental retardation. This child shows radiological and clinical features of SPONASTRIME dysplasia. Only three ... [more ▼]

We report a child with short stature, osteopenia with metaphyseal striations and severe mental retardation. This child shows radiological and clinical features of SPONASTRIME dysplasia. Only three sibships with this disorder have been reported. In two families, affected patients were of normal intelligence. In the third one, as well as our case, the dysplasia was complicated by severe mental retardation of unknown origin. The severity of the retardation in our case and a previous report, and some difference in the gestalt and radiological aspects, suggest that SPONASTRIME dysplasia is a heterogeneous disorder. We provisionally propose to split SPONASTRIME dysplasia in two phenotypically distinct subgroups, and to delineate here a 'new' variant with microcephaly and severe mental impairment. [less ▲]

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See detailHeterogeneity of systemic oxidative stress profiles in COPD : a potential role of gender
Maury, Jonathan; Gouzi, Fares; De Rigal, Philippe et al

in Oxidative Medicine and Cellular Longevity (2015)

Detailed reference viewed: 23 (9 ULg)