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See detailThe effects of age and location on the biomechanical and biochemical properties of canine tracheal ring cartilage.
Hamaide, Annick ULg; Arnoczky, Steven; Ciarelli, Mike et al

in American Journal of Veterinary Research (1998), 59

Detailed reference viewed: 16 (5 ULg)
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See detailThe effects of age and location on the biomechanical and biochemical properties of canine tracheal ring cartilage.
Hamaide, Annick ULg; Arnoczky, Steven; Ciarelli, Mike et al

Poster (1996)

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See detailEffects of age on plasma metabolites and hormones in finishing Belgian Blue double-muscled cull females
Cabaraux, Jean-François ULg; Dufrasne, Isabelle ULg; Istasse, Louis ULg et al

in Animal Science (2004), 78(Part 2), 229-235

Two groups of 12 Belgian Blue double-muscled cull females were used successively in a 2-year repeated experiment and divided into three groups according to age, allowing four animals per group each year ... [more ▼]

Two groups of 12 Belgian Blue double-muscled cull females were used successively in a 2-year repeated experiment and divided into three groups according to age, allowing four animals per group each year. The aim of the trial was to relate, during the finishing period, the metabolic and endocrine parameters with age. Females were fattened with a diet based on maize silage and were blood sampled on several occasions. The average daily gain (ADG) decreased with the age of the cows. Plasma glucose and triglycerides decreased also with age while the youngest females showed lower concentrations of urea than those older. The composition of plasma non-esterified fatty acids also differed considerably between groups. The hormones that best related with ADG were IGF-1 and insulin. Plasma concentrations of thyroid hormones were lower in the oldest animals. No difference between groups was found for GH. Heifers presented lower concentrations of GH and IGF-1 than those reported elsewhere in fattening bulls of the same breed. It may be concluded that in Belgian Blue double-muscled females, glucose, IGF-1 and insulin are good indicators of the growth potential. Young adult cows presented intermediate characteristics of metabolic and endocrine status that were close either to younger or to older cows. [less ▲]

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See detailEffects of age, adipose percent, and reproduction on PCB concentrations and profiles in an extreme fasting north pacific marine mammal
Peterson, S. H.; Hassrick, J. L.; Lafontaine, Anne ULg et al

in PLoS ONE (2014), 9(4), 96191

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See detailEffects of agents' mobility on opinion spreading in Sznajd model
Sousa, A. O.; Yu-Song, T.; Ausloos, Marcel ULg

in European Physical Journal B -- Condensed Matter (2008), 66(1), 115-124

Under synchronous updating and allowing the agents to move in the lattice or underlying network, we find that the Sznajd model always reaches a consensus as a steady state, - because agent frustrations ... [more ▼]

Under synchronous updating and allowing the agents to move in the lattice or underlying network, we find that the Sznajd model always reaches a consensus as a steady state, - because agent frustrations are removed due to their diffusion. Moreover, we succeed in obtaining the well-known phase transition of the traditional Sznajd model, which depends on the initial concentration of individuals following an opinion. How the time for reaching consensus depends on the system size, and on the topology have been exhaustively investigated. The analyzed topologies were: annealed and quenched dilution on a square lattice, as well as on a variant of the well-known Barabasi-Albert model, called triad network. [less ▲]

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See detailEffects of aggressive encounters on plasma corticosteroid-binding globulin and its ligands in white-crowned sparrows.
Charlier, Thierry ULg; Underhill, Caroline; Hammond, Geoffrey L. et al

in Hormones & Behavior (2009), 56(3), 339-47

In birds, corticosteroid-binding globulin (CBG) binds corticosterone, progesterone and testosterone. The concentration of each ligand can alter the binding of the other ligands through competitive ... [more ▼]

In birds, corticosteroid-binding globulin (CBG) binds corticosterone, progesterone and testosterone. The concentration of each ligand can alter the binding of the other ligands through competitive interactions. Thus, an increase in corticosterone or progesterone may displace testosterone bound to CBG, leading to an increase in bioactive free testosterone levels without affecting total testosterone levels in the circulation. Aggressive interactions increase plasma total testosterone levels in some birds but not in others. Here, we tested the hypothesis that aggressive encounters in the late breeding season would not increase total testosterone levels in plasma, but would alter CBG, total corticosterone or total progesterone levels in such a way as to modify the number of available binding sites and therefore occupancy by testosterone. A marked decrease in CBG occupancy by testosterone would indirectly suggest an increase in free testosterone levels in plasma. Wild male white-crowned sparrows were exposed to a simulated territorial intrusion (STI) or control for 30 min. Subjects were then caught and bled. We measured CBG using a ligand-binding assay and corticosterone, progesterone and testosterone using highly sensitive radioimmunoassays. STI significantly increased aggressive behaviors but did not affect plasma total testosterone levels. STI significantly increased plasma CBG and total corticosterone levels and decreased plasma total progesterone levels. We predict that CBG occupancy by corticosterone will increase slightly following an aggressive encounter. However, this small change is unlikely to increase free testosterone levels, because of the large number of seemingly unoccupied CBG binding sites in these subjects. [less ▲]

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See detailEffects of aging and daytime recovery sleep on N-REM slow oscillations
Lafortune, M; Viens, I; Poirier, J et al

Poster (2009, April)

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See detailEffects of aging and daytime recovery sleep on N-REM slow oscillations
Lafortune, M; Viens, I; Poirier, G et al

in Sleep (2009), 32(Suppl. 1),

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See detailThe effects of aging on location-based and distance-based processes in memory for time
Bastin, Christine ULg; Van der Linden, Martial ULg; Michel, Anne-Pascale et al

in Acta Psychologica (2004), 116

Retrieving when an event occurred may depend on an estimation of the age of the event (distance-based processes) or on strategic reconstruction processes based on contextual information associated with ... [more ▼]

Retrieving when an event occurred may depend on an estimation of the age of the event (distance-based processes) or on strategic reconstruction processes based on contextual information associated with the event (location-based processes). Young and older participants performed a list discrimination task that has been designed to dissociate the contribution of both types of processes. An adapted Remember/Know/Guess procedure [Can. J. Exp. Psychol. 50 (1996) 114] was developed to evaluate the processes used by the participants to recognize the stimuli and retrieve their list of occurrence. The results showed that aging disrupts location- based processes more than distance-based processes. In addition, a limitation of speed of processing and working-memory capacities was the main predictor of age-related differences on location-based processes, whereas working-memory capacities mediated partly age differences on distance-based processes. [less ▲]

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See detailEffects of aging on task- and stimulus-related attention during a working memory task
Kurth, Sophie ULg; Hagelstein, Catherine ULg; Collette, Fabienne ULg et al

in Proceedings of the Annual Meeting of the Belgian Association for Psychological Sciences (2013)

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See detailEffects of aging on task- and stimulus-related cerebral attention networks
Kurth, Sophie ULg; Majerus, Steve ULg; Bastin, Christine ULg et al

in Neurobiology of Aging (2016), 44

Interactions between a dorsal attention (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short term memory (STM) tasks. Since it remains an ... [more ▼]

Interactions between a dorsal attention (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short term memory (STM) tasks. Since it remains an under-investigated question, age effects on DAN and VAN activity and their functional balance were explored during performance of a STM task. Older and young groups showed similar behavioral patterns of results. At the cerebral level, DAN activation increased as a function of increasing STM load in both groups, suggesting preserved activity in DAN during healthy aging. Age-related over-recruitment in regions of the DAN in the higher task load raised the question of compensation attempt versus less efficient use of neural resources in older adults. Lesser decrease of VAN activation with increasing load and decreased stimulus-driven activation in the VAN, especially in the higher load, in older participants suggested age-related reduced response in the VAN. However, functional connectivity measures showed that VAN was still functionally connected to the DAN in older participants. [less ▲]

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See detailThe effects of aging on the recognition of different types of associations
Bastin, Christine ULg; Van der Linden, Martial ULg

in Experimental Aging Research (2006), 32

The present study examined how aging influences item and associative recognition memory, and compared memory for two types of associations: associations between the same kinds of information and ... [more ▼]

The present study examined how aging influences item and associative recognition memory, and compared memory for two types of associations: associations between the same kinds of information and associations between different kinds of information. A group of young adults and a group of older adults performed a forced-choice face recognition task and two multitrial forced-choice associative recognition tasks, assessing memory for face-face and face-spatial location associations. The results showed disproportionate age-related decline of associative recognition compared to intact item recognition. Moreover, aging affected both types of associative tasks in the same way. The findings support an associative deficit hypothesis (Naveh-Benjamin, Journal of Experimental Psychology: Learning, Memory and Cognition, 26, 1170–1187, 2000), which attributes a substantial part of the age effect on episodic memory tasks to difficulty with binding individual components into a cohesive memory trace. This associative deficit seems to affect same-information associations, as well as different-information associations. [less ▲]

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See detailThe effects of aging on verbal short-term memory and word production capacities
Verhaegen, Clémence ULg; Poncelet, Martine ULg

Poster (2012, June)

The effects of aging on verbal short-term memory (STM) are still a matter of debate (e.g., Nilsson et al., 2003). Recent models of STM distinguish processes involved in the retention of item information ... [more ▼]

The effects of aging on verbal short-term memory (STM) are still a matter of debate (e.g., Nilsson et al., 2003). Recent models of STM distinguish processes involved in the retention of item information (i.e., the identity of words) and order information (i.e., the order of presentation of items) (see Majerus, 2008, for a review). Finally, these models also incorporate relationships between STM and word production capacities, which are often impaired in aging (Burke et al., 1991). The aims of this study are (1) to explore the effects of aging on both item and order STM capacities, (2) to explore the effects of aging on naming capacities and (3) to explore the relationships between STM and naming in aging. Three groups of participants participated in the present study: (1) 56-64 years old (N=26) – (2) 65-74 years old (N=23) – (3) 75-84 years old (N=22). The participants' hearing thresholds were analyzed with a pure tone audiometer. The participants were asked to perform STM tasks and a picture naming task. The results confirm the presence of naming difficulties in participants above 65 years of age, as previously shown by Verhaegen and Poncelet (in press). By contrast, in STM, the differences become non significant when the hearing status is controlled for. However, the items are presented auditorily in all STM tasks. Therefore, in order to confirm the absence of age-related differences in STM, it would be of interest to assess the participants with visual STM tasks. [less ▲]

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See detailEffects of agricultural land use on fluvial carbon dioxide, methane and nitrous oxide concentrations in a large European river, the Meuse (Belgium)
Borges, Alberto ULg; Darchambeau, F.; Lambert, T et al

in Science of the Total Environment (2018), 610–611

We report a data-set of CO2, CH4, and N2O concentrations in the surface waters of the Meuse river network in Belgium, obtained during four surveys covering 50 stations (summer 2013 and late winter 2013 ... [more ▼]

We report a data-set of CO2, CH4, and N2O concentrations in the surface waters of the Meuse river network in Belgium, obtained during four surveys covering 50 stations (summer 2013 and late winter 2013, 2014 and 2015), from yearly cycles in four rivers of variable size and catchment land cover, and from 111 groundwater samples. Surface waters of the Meuse river network were over-saturated in CO2, CH4, N2O with respect to atmospheric equilibrium, acting as sources of these greenhouse gases to the atmosphere, although the dissolved gases also showed marked seasonal and spatial variations. Seasonal variations were related to changes in freshwater discharge following the hydrological cycle, with highest concentrations of CO2, CH4, N2O during low water owing to a longer water residence time and lower currents (i.e. lower gas transfer velocities), both contributing to the accumulation of gases in the water column, combined with higher temperatures favourable to microbial processes. Inter-annual differences of discharge also led to differences in CH4 and N2O that were higher in years with prolonged low water periods. Spatial variations were mostly due to differences in land cover over the catchments, with systems dominated by agriculture (croplands and pastures) having higher CO2, CH4, N2O levels than forested systems. This seemed to be related to higher levels of dissolved and particulate organic matter, as well as dissolved inorganic nitrogen in agriculture dominated systems compared to forested ones. Groundwater had very low CH4 concentrations in the shallow and unconfined aquifers (mostly fractured limestones) of the Meuse basin, hence, should not contribute significantly to the high CH4 levels in surface riverine waters. Owing to high dissolved concentrations, groundwater could potentially transfer important quantities of CO2 and N2O to surface waters of the Meuse basin, although this hypothesis remains to be tested. [less ▲]

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See detailEFFECTS OF AGRICULTURAL PRACTICES AND HEAVY METAL CONTAMINATION ON THE COMMUNITY DYNAMICS OF EARTHWORMS IN RELATION TO SOIL PHYSICAL AND CHEMICAL FACTORS IN AGRICULTURAL FIELDS (BELGIUM)
Lemtiri, Aboulkacem ULg

Doctoral thesis (2015)

We investigated the effect of different agricultural practices on the abundances, biomass, and species diversity of earthworms. Specifically, we aimed to identify the relationship between certain soil ... [more ▼]

We investigated the effect of different agricultural practices on the abundances, biomass, and species diversity of earthworms. Specifically, we aimed to identify the relationship between certain soil physico-chemical properties and earthworm communities in agricultural soils. Two tillage systems and crop residue management were investigated. After conducting the study over four years, we found that the abundance, biomass, and diversity of earthworms were negatively affected by tillage application and the removal of crop residues. All ecological groups were negatively affected by conventional tillage system and crop residues exportation. However, crop residues removal had a greater impact than the conventional tillage system. In this study area, the earthworm community was dominated by the endogeic species A. c. caliginosa (64%), while few epigeic and anecic species were observed (5%). Endogeic and epi-anecic (L. terrestris) species appeared to be highly influenced by tillage and of crop residues exportation. When crop residues were exported from the field, the concentrations of chemical elements were low, particularly P and K nutrients. Earthworm activity contributed to nutrient dynamics and soil structure after four years of incorporating of crop residues to the fields and reduced tillage application. No consistent relationship was detected between soil and earthworm variables, even though different soil properties responded differently with respect to the tillage systems, crop residues removal and the presence of certain earthworm species. The number of years that our field was managed might have also affected our results.On the basis of the primarily research focused on understanding how earthworms participate and contribute towards improving soil quality (structure, nutrient dynamics and fertility), we subsequently focused on investigating how two plants (Vicia faba and Zea mays) and the Eisenia fetida earthworm contribute to uptake of different metals: Cd, Zn, Pb and Cu from the land surrounding of a former Zn-Pb ore treatment plant. Specifically, we tested whether the earthworm Eisenia fetida could act as a catalyzor to enhance phytoremediation efficiency. After 42 days of exposure, our results showed that certain earthworm life-cycle traits are affected by metal contamination and by the addition of plants. Specifically, the concentrations of metals in earthworm tissues decreased in the presence of plants. Our findings demonstrate that earthworm activities modify the availability of metals in soils, enhancing metal uptake by plants. This innovative system offers new investigation possibilities by considering earthworm-plant-soil interaction. In conclusion, this work confirmed that earthworms are important catalyzor optimizing the phytoremediation processes of polluted soils. [less ▲]

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See detailEffects of allele frequency estimation on genomic predictions and inbreeding coefficients.
VanRaden, P. M.; Tooker, M. E.; Gengler, Nicolas ULg

in Journal of Dairy Science (2008, July), 91

Genetic calculations often require estimating allele frequencies, which differ across time due to selection and drift. Data were 50,000 simulated markers and 39,985 actual markers for 2391 genotyped ... [more ▼]

Genetic calculations often require estimating allele frequencies, which differ across time due to selection and drift. Data were 50,000 simulated markers and 39,985 actual markers for 2391 genotyped Holstein bulls. Gene content of relatives and gene frequencies in the base (founder) population were estimated using pedigrees and a linear model. Ancestors born since 1950 were included, for a total of 22,088 animals. Because pedigrees were very complete, only one unknown-parent group was used. Convergence to 5 digits of accuracy required about 1000 iterations. Total time was 2 processor days and proportional to number of animals times markers, but actual clock time was reduced by processing loci on separate chromosomes in parallel. Simple allele frequencies were obtained from only the known genotypes. True base frequencies were correlated with estimated base frequencies by 0.98 versus 0.94 with simple frequencies. Genomic predictions and inbreeding coefficients were computed in four ways, using true or estimated base frequencies, simple frequencies, or an “estimate” of .5 for each marker. When allele frequencies estimates were used instead of 0.5 to assign mixed model coefficients, solutions converged more slowly but predictions were more accurate. From simulated data, realized reliabilities for young bulls were 62.8% using either true or estimated base frequencies, 62.6% using simple frequencies, and 62.0% using frequencies set to 0.5. Pedigree and genomic inbreeding coefficients were correlated by 0.73 using true base frequencies, 0.67 using estimated base frequencies, 0.12 using simple frequencies, and 0.72 when frequencies were set to 0.5. Genomic inbreeding coefficients were biased downward by 7% to 9% using either frequency estimate, upward by 31% using 0.5, but were reasonable when true frequencies were used. Frequency estimation had small effects on genomic predictions but large effects on genomic inbreeding coefficients in both simulated and real data. [less ▲]

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See detailEffects of allelochemicals from first (Brassicaceae) and second (Myzus persicae and Brevicoryne brassicae) trophic levels on Adalia bipunctata
Francis, Frédéric ULg; Lognay, Georges ULg; Wathelet, Jean-Paul ULg et al

in Journal of Chemical Ecology (2001), 27(2), 243-256

Three Brassicaceae species, Brassica napus (low glucosinolate content), Brassica nigra (including sinigrin), and Sinapis alba (including sinalbin) were used as host plants for two aphid species: the ... [more ▼]

Three Brassicaceae species, Brassica napus (low glucosinolate content), Brassica nigra (including sinigrin), and Sinapis alba (including sinalbin) were used as host plants for two aphid species: the generalist Myzus persicae and the specialist Brevicoryne brassicae. Each combination of aphid species and prey host plant was used to Feed the polyphagous ladybird beetle, Adalia bipunctata. Experiments with Brassicaceae species including different amounts and kinds of glucosinolates (GLS) showed increased ladybird larval mortality at higher GLS concentrations. When reared on plants with higher GLS concentrations, the specialist aphid, B. brassicae, was found to be more toxic than M. persicae. Identification of GLS and related degradation products, mainly isothiocyanates (ITC), was investigated in the first two trophic levels, plant and aphid species, by high-performance liquid chromatography and gas chromatography-mass spectrometry, respectively. While only GLS were detected in M. persicae on each Brassicaceae species, high amounts of ITC were identified in B. brassicae samples (allyl-ITC and benzyl-ITC from B. nigra and S. alba, respectively) from all host plants. Biological effects of allelochemicals from plants on predators through aphid prey are discussed in relation to aphid species to emphasize the role of the crop plant in integrated pest management in terms of biological control efficacy. [less ▲]

Detailed reference viewed: 44 (7 ULg)