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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 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 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 ▲]

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See detailEffects of Alpha-Hederin, a Saponin Extracted from Hedera Helix, on Cells Cultured in Vitro
Danloy, S.; Quetin-Leclercq, J.; Coucke, P. et al

in Planta Medica (1994), 60(1), 45-9

In this work, we have analysed the effects of alpha-hederin, a monodesmosidic triterpenoid saponin isolated from Hedera helix, on mouse B16 melanoma cells and non-cancer mouse 3T3 fibroblasts cultured in ... [more ▼]

In this work, we have analysed the effects of alpha-hederin, a monodesmosidic triterpenoid saponin isolated from Hedera helix, on mouse B16 melanoma cells and non-cancer mouse 3T3 fibroblasts cultured in vitro. Our results indicate that, in a serum-free medium, alpha-hederin is cytotoxic and inhibits proliferation in both cell lines at rather low concentrations (< 5 micrograms/ml) after only 8 hours of treatment. Its cytotoxicity decreases in the presence of serum in which BSA seems to be able to bind the saponin. alpha-Hederin also induces vacuolization of the cytoplasm and membrane alterations leading to cell death. [less ▲]

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See detailEffects of Alpha-Methyl-Para-Tyrosine on Monoamine Levels in the Japanese Quail: Sex Differences and Testosterone Effects
Balthazart, Jacques ULg; Foidart, Agnès ULg; Sante, P. et al

in Brain Research Bulletin (1992), 28(2), 275-88

Experiments were performed to obtain more information on the regulation by steroids of catecholaminergic systems in the brain of Japanese quail. Dose-response and time-response experiments were first ... [more ▼]

Experiments were performed to obtain more information on the regulation by steroids of catecholaminergic systems in the brain of Japanese quail. Dose-response and time-response experiments were first performed to determine optimal conditions for measuring turnover in the quail brain. The norepinephrine and dopamine turnover were then estimated in microdissected brain nuclei of birds that were either sexually mature or gonadectomized or gonadectomized and treated with testosterone. Two major facts that bear direct relationship with the control of masculine reproductive behavior were demonstrated. On one hand, the dopamine turnover in the medial preoptic nucleus, a sexually dimorphic brain structure which is critically implicated in the control of copulatory behavior was much higher in male than in female quail irrespective of the hormonal condition of the birds. On the other hand, norepinephrine concentrations appeared to be higher in several nuclei of the female brain by comparison with males. These sex differences might represent part of the causal factors that underlie the sex dimorphism in reproductive behavior in quail. [less ▲]

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See detailEffects of alternate reef states on coral reef fish habitat associations
Lecchini, David; Carassou, Laure; Frederich, Bruno ULg et al

in Environmental Biology of Fishes (2012), 94(2), 421-429

The present study describes ontogenetic shifts in habitat use for 15 species of coral reef fish at Rangiroa Atoll, French Polynesia. The distribution of fish in different habitats at three ontogenetic ... [more ▼]

The present study describes ontogenetic shifts in habitat use for 15 species of coral reef fish at Rangiroa Atoll, French Polynesia. The distribution of fish in different habitats at three ontogenetic stages (new settler, juvenile, and adult) was investigated in coral- dominated and algal-dominated sites at two reefs (fringing reef and inner reef of motu). Three main ontogenetic patterns in habitat use were identified: (1) species that did not change habitats between new settler and juvenile life stages (60% of species) or between juvenile and adult stages (55% of species—no ontoge- netic shift); (2) species that changed habitats at different ontogenetic stages (for the transition “new settler to juvenile stage”: 15% of species; for the transition “juvenile to adult stage”: 20% of species); and (3) species that increased the number of habitats they used over ontogeny (for the transition “new settler to juvenile stage”: 25% of species; for the transition “juvenile to adult stage”: 25% of species). Moreover, the majority of studied species (53%) showed a spatial variability in their ontogenetic pattern of habitat use according to alternate reef states (coral reef vs algal reef), suggesting that reef state can influence the dynamics of habitat associations in coral reef fish. [less ▲]

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See detailEffects of Alzheimer's disease on the recognition of novel versus familiar words : Neuropsychological and clinico-metabolic data
Lekeu, Françoise ULg; Van der Linden, Martial ULg; Degueldre, Christian ULg et al

in Neuropsychology (2003), 17(1), 143-154

This study explored recognition memory performance for novel versus familiar words in Alzheimer's disease (AD) patients and normal controls (NCs), using an adaptation of E. Tulving and N. Kroll's (1995 ... [more ▼]

This study explored recognition memory performance for novel versus familiar words in Alzheimer's disease (AD) patients and normal controls (NCs), using an adaptation of E. Tulving and N. Kroll's (1995) procedure. Results showed that both groups exhibited more hits and more false alarms for familiar than for novel words. The groups did not differ in the recognition of familiar words, reflecting preserved familiarity processes in AD. However, AD patients made more false alarms than NCs in the recognition of novel words, reflecting impairment of recollection processes in AD. A positron emission tomography analysis of clinico-metabolic correlations in AD patients showed a correlation between recognition of novel words and right hippocampal activity, whereas recognition of familiar words was more related to metabolic activity in the left posterior orbitofrontal cortex. [less ▲]

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See detailThe effects of ammonium sulphate deposition and root sinks on soil solution chemistry in coniferous forest soils
Carnol, Monique ULg; Ineson, Phil; Anderson, J. M. et al

in Biogeochemistry (1997), 38

The effects of enhanced (NH4)(2)SO4 deposition on soil solution cation and anion concentrations and annual ionic fluxes were followed using a standardised experimental protocol in six European coniferous ... [more ▼]

The effects of enhanced (NH4)(2)SO4 deposition on soil solution cation and anion concentrations and annual ionic fluxes were followed using a standardised experimental protocol in six European coniferous forests with contrasting soil types, pollution inputs and climate. Native soil cores containing a ceramic suction cup were installed in the field, roofed and watered every two weeks with local throughfall or local throughfall with added (NH4)(2)SO4 at 75 kg NH4+-N ha(-1) a(-1). Living root systems were established in half of the lysimeters. Untreated throughfall NH4+-N deposition at the sites ranged from 3.7 to 29 kg ha(-1) a(-1). Soil leachates were collected at two weekly intervals over 12 months and analysed for volume, and concentrations of major anions and cations. Increases in soil solution NO3- concentrations in response to N additions were observed after 4-9 months at three sites, whilst one sandy soil with high C:N ratio failed to nitrify under any of the treatments. Changes in NO3- concentrations in soil solution controlled soil solution cation concentrations in the five nitrifying soils, with Al3+ being the dominant cation in the more acid soils with low base saturation. The acidification responses of the soils to the (NH4)(2)SO4 additions were primarily related to the ability of the soils to nitrify the added NH4+. pH and soil texture seemed important in controlling NH4+ leaching in response to the treatments, with two less acidic, clay/clay loam sites showing almost total retention of added NH4+, whilst nearly 75% of the added N was leached as NH4+ at the acid sandy soils. The presence of living roots significantly reduced soil solution NO3- and associated cation concentrations at two of the six sites. The very different responses of the six soils to increased (NH4)(2)SO4 deposition emphasise that the establishment of N critical loads for forest soils need to allow for differences in N storage. capacity and nitrification potential. [less ▲]

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See detailEffects Of An Anabolic Treatment Before Puberty With Trenbolone Acetate-Oestradiol Or Estradiol Alone On Growth-Rate, Testicular Development And Luteinizing-Hormone And Testosterone Plasma-Concentrations
Renaville, Robert ULg; Burny, Arsène; Sneyers, Myriam et al

in Theriogenology (1988), 29(2), 461-476

Scrotal circumference, growth and hormonal status after prepubertal anabolic treatments were studied in 18 conventional Belgian White Blue bulls from 3 to 13 mo of age. Young bulls were assigned into ... [more ▼]

Scrotal circumference, growth and hormonal status after prepubertal anabolic treatments were studied in 18 conventional Belgian White Blue bulls from 3 to 13 mo of age. Young bulls were assigned into three groups: six untreated (control) bulls, six bulls implanted with 140 mg trenbolone acetate + 20 mg oestradiol (Revalor; TBA-E2) and six bulls treated with 45 mg oestradiol (Compudose; E2). Mean scrotal circumference was similar in the three groups at Day O (between 13.0 ± 0.3 cm to 13.4 ± 0.7 cm). From Days O to 230, scrotal circumference was strongly inhibited in implanted bulls, 23.2 ± 1.4, 21.7 ± 1.0 cm, respectively, for TBA-E2 and E2 at Day 210, as compared with 29.5 ± 2.2 cm in control bulls (P < 0.001). Afterwards, differences lessened gradually and no significant divergence was observed between the three groups from Day 310. Average plasma luteinizing hormone (LH) concentrations were similar in the three groups throughout the assay. Mean testosterone levels remained extremely low upto Day 150 in TBA-E2 and E2 groups (0.6 ± 0.6, 1.2 ± 0.7 ng/ml, respectively) before they increased abruptly and reached values observed in control bulls at Day 180 (4.0 ± 1.9 ng/ml). The pulsatil character of LH and testosterone profiles was abolished by the anabolic treatments. Luteinizing hormone-releasing hormone (LHRH) injection was followed by an immediate and sharp increase in plasma LH concentrations in all groups at Day 0. Anabolic treatments strongly reduced LH and testosterone responses to LHRH in treated groups. [less ▲]

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See detailEffects of an enriched environment on fear reactions in sheep.
Bouissou, M. F.; Vandenheede, Marc ULg

Conference (1995)

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