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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 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 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 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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