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See detailQuantification of the Carbonate Pump: Case study of an Emiliania huxleyi bloom in the Bay of Biscay
Harlay, Jérôme ULg; Chou, Lei; Roevros, Nathalie et al

Poster (2003, April 03)

Little attention has been paid until now to the processes controlling the production, dissolution and fate of biogenic calcium carbonate in the oceans. It is however well known that net deposition rates ... [more ▼]

Little attention has been paid until now to the processes controlling the production, dissolution and fate of biogenic calcium carbonate in the oceans. It is however well known that net deposition rates of inorganic carbon to the sediments are comparable to those of organic matter. There remains still large uncertainties in the production and redissolution of biogenic carbonate in the marine system and thus about the role of the carbonate pump in response to anthropogenic CO2 perturbations. The understanding of these processes is also a prerequisite to predict the response of marine organisms to global environmental changes. In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophorid blooms occur frequently. The study focuses on processes associated with the oceanic production and dissolution of calcium carbonate, by combining field investigations, laboratory experiments and modelling efforts. Remote sensing demonstrates a close relationship between vertical mixing along the continental margin and the development of the phytoplankton bloom. We will present here, results of 14C incorporation experiments used to evaluate the rate of production of organic and inorganic particulate carbon, obtained during a coccolithophorid spring bloom in the investigated area. A tentative mass balance of the carbon fluxes for this area will be presented, confirming the importance that the calcium carbonate pump may play in the oceanic system. [less ▲]

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See detailEffect of stocking density on the dynamics of cannibalism in sibling larvae of Perca fluviatilis under controlled conditions
Baras, E.; Kestemont, P.; Mélard, Charles ULg

in Aquaculture (2003), 219(1-4), 241-255

The effect of stocking density (10, 31.6 and 100 larvae 1(-1); three replicates per treatment) on the day-by-day dynamics of survival, growth and cannibalism was examined in sibling perch larvae reared ... [more ▼]

The effect of stocking density (10, 31.6 and 100 larvae 1(-1); three replicates per treatment) on the day-by-day dynamics of survival, growth and cannibalism was examined in sibling perch larvae reared from eyed-egg stage in 100-1 cages (16L:8D, 20.0 +/- 0.5 degreesC, O-2 greater than or equal to 6.0 mg 1(-1); feeding in excess with live Artemia nauplii during the photophase) during the first 3 weeks of exogenous feeding. Larvae unable to achieve the transition to exogenous feeding died in between 7 and I I days post-hatch. Later, mortality from causes other than cannibalism never exceeded 1% day(-1). Cannibalism did not start before days 10 - 11 and first consisted in the incomplete ingestion of prey attacked tail first, exclusively. This type of cannibalism never caused losses higher than 2.0% of the initial stock, and ceased after days 16-18. From days 12-14 onwards, differential growth was apparent, and cannibals turned to complete cannibalism of small prey ingested head first, which caused greater losses (28-53% of the stock). Increasing the stocking density did not compromise growth and decreased the overall impact of cannibalism through several complementary mechanisms: (i) a postponed emergence of cannibalism, (ii) a lower proportion of cannibals in the population, and (iii) probably a lower rate of cannibalism per capita as predation was complicated and less directed at high stocking density. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailPregnancy and the immune system: between tolerance and rejection
Thellin, Olivier ULg; Heinen, Ernst ULg

in Toxicology (2003), 185(3), 179-184

Interactions between the conceptus and the mother are bi-directional: the feto-placental tissues need nutrition and a suitable environment in homeostatic condition whereas the mother influenced by the ... [more ▼]

Interactions between the conceptus and the mother are bi-directional: the feto-placental tissues need nutrition and a suitable environment in homeostatic condition whereas the mother influenced by the placental factors adapts her metabolism and immune system. Many different mechanisms acting locally or at distance ensure tolerance of the semi-allogeneic graft by the maternal natural and adaptive immune defences. In front of this tolerance, mechanisms exist ensuring rejection of the conceptus by the mother (spontaneous abortion) through rupture of one or more tolerance mechanisms, notably in stress situations endangering the mother. Thus outcome of a pregnancy is dependent on efficiently working tolerance mechanisms, and rupture of such mechanisms can lead to rejection. The balance of influence leading either to tolerance or rejection is under control of internal (maternal and fetal) and external (environmental) factors. Rejection, if triggered, mainly occurs through immune-induced inflammation, tissue degradation and coagulation. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. [less ▲]

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See detailA new seismic analysis of Alpha Centauri
Thoul, Anne ULg; Scuflaire, Richard ULg; Noels-Grötsch, Arlette ULg et al

in Astronomy and Astrophysics (2003), 402(1), 293-297

Models of alpha Cen A & B have been computed using the masses determined by Pourbaix et al. (\cite{Po2002}) and the data derived from the spectroscopic analysis of Neuforge & Magain (\cite{Ne1997}). The ... [more ▼]

Models of alpha Cen A & B have been computed using the masses determined by Pourbaix et al. (\cite{Po2002}) and the data derived from the spectroscopic analysis of Neuforge & Magain (\cite{Ne1997}). The seismological data obtained by Bouchy & Carrier (\cite{Bo2001}, \cite{Bo2002}) do help improve our knowledge of the evolutionary status of the system. All the constraints are satisfied with a model which gives an age of about 6 Gyr for the binary. [less ▲]

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See detailSpectroscopic mode identification for the slowly pulsating B star HD 147394
Briquet, Maryline ULg; Aerts, C.; Mathias, P. et al

in Astronomy and Astrophysics (2003), 401

We present ground-based high-resolution high S/N spectra of the slowly pulsating B star HD 147394. Two frequencies are clearly found in the moments of the Si II 4128-4130 doublet: f[SUB]1[/SUB]=0.8008 c d ... [more ▼]

We present ground-based high-resolution high S/N spectra of the slowly pulsating B star HD 147394. Two frequencies are clearly found in the moments of the Si II 4128-4130 doublet: f[SUB]1[/SUB]=0.8008 c d[SUP]-1[/SUP] and f[SUB]2[/SUB]=0.7813 c d[SUP]-1[/SUP]. The frequency f[SUB]1[/SUB] is also found in the HIPPARCOS data. A third frequency is also present in our spectroscopic data: f[SUB]3[/SUB]=0.7175 c d[SUP]-1[/SUP] or its aliases due to the time sampling. A mode identification is performed by means of a new version of the moment method optimized for multiperiodic signals. It points towards several equivalent solutions of non-axisymmetric l <=3 for all three modes. We have too limited information to perform seismic modelling at this stage, but we do show that the different possibilities for the mode identifications are compatible with pulsational models for SPBs. Based on observations obtained with the spectrograph Aurélie attached to the 1.52-m telescope of the Observatoire de Haute-Provence, France. [less ▲]

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See detailAn X-ray investigation of the NGC 346 field in the Small Magellanic Cloud. II. The field population
Nazé, Yaël ULg; Hartwell, J. M.; Stevens, I. R. et al

in Astrophysical Journal (2003), 586(2, Part 1), 983-995

We present results from a Chandra observation of the NGC 346 cluster, which is the ionizing source of N66, the most luminous H II region and the largest star formation region in the SMC. In the first part ... [more ▼]

We present results from a Chandra observation of the NGC 346 cluster, which is the ionizing source of N66, the most luminous H II region and the largest star formation region in the SMC. In the first part of this investigation, we have analyzed the X-ray properties of the cluster itself and the remarkable star HD 5980, but the field contains additional objects of interest. In total, 75 X-ray point sources were detected in the Chandra observation: this is 5 times the number of sources detected by previous X-ray surveys. We investigate here their characteristics in detail. Because of high foreground absorption, the sources possess rather high hardness ratios. Their cumulative luminosity function appears generally steeper than that for the rest of the SMC at higher luminosities. Their absorption columns suggest that most of the sources belong to NGC 346. Using Digitized Sky Survey data and new UBVRI imaging with the ESO 2.2 m telescope, we also discovered possible counterparts for 32 of these X-ray sources and estimated a B spectral type for a large number of these counterparts. This tends to suggest that most of the X-ray sources in the field are in fact X-ray binaries. Finally, some objects show X-ray and/or optical variability, with a need for further monitoring. [less ▲]

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See detailLate Quaternary clay mineral record in Central Lake Baikal (Academician Ridge, Siberia)
Fagel, Nathalie ULg; Boski, T.; Likhoshway, L. et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2003), 193(1), 159-179

We investigated the mineralogical composition of two cores recovered on the Academician Ridge (Central Lake Baikal, Siberia). Sedimentological features show that the cores are unaffected by turbidity ... [more ▼]

We investigated the mineralogical composition of two cores recovered on the Academician Ridge (Central Lake Baikal, Siberia). Sedimentological features show that the cores are unaffected by turbidity currents. However, hemipelagic deposition is not continuous, but intermittently disturbed by syn- or post-sediment reworking (e.g., bioturbation, slumps, faulting). Such modes of deposition are consistent with the complex uplift history of the ridge. Bulk mineralogy suggests that terrigenous sediment supplies are constant through glacial/interglacial stages, and diluted by diatom-rich intervals related to warmer interglacial stages. The core stratigraphy is based on the correlation of the diatom zonation and opal abundance with the marine oxygen isotope reference curve SPECMAP. The similar to 8-m cores partly recover the last four interglacial/glacial cycles, i.e., since oxygen isotope stage 8. We test the use of clay minerals as a proxy for paleoclimatic reconstruction. The clays are more weathered during the diatom-rich intervals in agreement with warmer climate conditions. However, the mean clay composition does not change significantly through glacial/interglacial stages. This observation implies that, in the Academician Ridge sediments, a simple smectite/illite ratio (S/I) does not alone provide a reliable indicator of climatic variation. It reflects the complex clay assemblages, especially the smectite group, delivered to Central Lake Baikal. Smectites include primarily illite-smectite mixed layers, made of a mixture of montmorillonite and beidellite. According to their behavior after cation saturation, the illite-smectite mixed layers are primarily transformed smectites, with some neoformed smectites intermittently observed. In addition, Al-smectites occur in minor proportions. We conclude that the S/I ratio has a climatic significance only if it evolves in parallel with the weathering stage of the clays and is confirmed by a change in the composition of the smectites. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailL'hypertension artérielle essentielle peut-elle être prevenue?
Krzesinski, Jean-Marie ULg; Saint-Remy, Annie ULg

in Revue Médicale de Liège (2003), 58(4), 198-205

Prevalence of arterial hypertension is growing, in particular due to population ageing. Hypertension is a major risk factor for cardiovascular morbidity and mortality. Prevention is conceivable on a ... [more ▼]

Prevalence of arterial hypertension is growing, in particular due to population ageing. Hypertension is a major risk factor for cardiovascular morbidity and mortality. Prevention is conceivable on a theoretical basis by reduction or, if possible, prevention of excess weight, diet modifications, increased physical activity among other means. To be efficient, prevention should include an early detection of patients at risk and a long term assessment of efficacy requiring many efforts from both patients and physicians. [less ▲]

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See detailEnhanced nutritionally induced adipose tissue development in mice with stromelysin-1 gene inactivation.
Maquoi, Erik ULg; Demeulemeester, Diego; Vörös, Gabor et al

in Thrombosis and Haemostasis (2003), 89(4), 696-704

To investigate a potential role of stromelysin-1 (MMP-3) in development of adipose tissue, 5 week old male MMP-3 deficient mice (MMP-3(-/-)) and wild-type (MMP-3(+/+)) controls were kept on a high fat ... [more ▼]

To investigate a potential role of stromelysin-1 (MMP-3) in development of adipose tissue, 5 week old male MMP-3 deficient mice (MMP-3(-/-)) and wild-type (MMP-3(+/+)) controls were kept on a high fat diet (HFD) for 15 weeks. MMP-3(-/-) mice were hyperphagic and gained more weight than the MMP-3(+/+) mice. At the time of sacrifice, the body weight of the MMP-3(-/-) mice was significantly higher than that of the MMP-3(+/+) mice, as was the weight of the isolated subcutaneous (SC) and gonadal (GON) fat deposits. Significant adipocyte hypertrophy was observed in the GON but not in the SC adipose tissue of MMP-3(-/-) mice. Fasting plasma glucose and cholesterol levels were comparable in both genotypes, whereas triglyceride levels were significantly lower in MMP-3(-/-) mice. Staining with an endothelial cell specific lectin revealed a significantly higher blood vessel density and larger total stained area in the GON adipose tissues of MMP-3(-/-) mice. Thus, in a murine model of nutritionally induced obesity, MMP-3 impairs adipose tissue development, possibly by affecting food intake and/or adipose tissue-related angiogenesis. [less ▲]

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See detailMetabolic enzymes from psychrophilic bacteria: Challenge of adaptation to low temperatures in ornithine carbamoyltransferase from Moritella abyssi
Xu, Y.; Feller, Georges ULg; Gerday, Charles ULg et al

in Journal of Bacteriology (2003), 185(7), 2161-2168

The enzyme ornithine carbamoyltransferase (OTCase) of Motitella abyssi (OTCase(Mab)), a new, strictly psychrophilic and piezophilic bacterial species, was purified. OTCase(Mab) displays maximal activity ... [more ▼]

The enzyme ornithine carbamoyltransferase (OTCase) of Motitella abyssi (OTCase(Mab)), a new, strictly psychrophilic and piezophilic bacterial species, was purified. OTCase(Mab) displays maximal activity at rather low temperatures (23 to 25degreesC) compared to other cold-active enzymes and is much less thermoresistant than its homologues from Escherichia coli or thermophilic procaryotes. In vitro the enzyme is in equilibrium between a trimeric state and a dodecameric, more stable state. The melting point and denaturation enthalpy changes for the two forms are considerably lower than the corresponding values for the dodecameric Pyrococcus furiosus OTCase and for a thermolabile trimeric mutant thereof. OTCase(Mab) displays higher K-m values for ornithine and carbamoyl phosphate than mesophilic and thermophilic OTCases and is only weakly inhibited by the bisubstrate analogue delta-N-phosphonoacetyl-L-ornithine (PALO). OTCase(Mab) differs from other, nonpsychrophilic OTCases by substitutions in the most conserved motifs, which probably contribute to the comparatively high K-m values and the lower sensitivity to PALO. The K. for ornithine, however, is substantially lower at low temperatures. A survey of the catalytic efficiencies (k(cat)/K-m) of OTCases adapted to different temperatures showed that OTCase(Mab) activity remains suboptimal at low temperature despite the 4.5-fold decrease in the K-m value for ornithine observed when the temperature is brought from 20 to 5degreesC. OTCase(Mab) adaptation to cold indicates a trade-off between affinity and catalytic velocity, suggesting that optimization of key metabolic enzymes at low temperatures may be constrained by natural limits. [less ▲]

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See detailModernisation de l’interface citoyen - fonction publique: vers une intégration réfléchie des TIC
Lisein, Olivier ULg

in Pyramides (2003), 7(Printemps), 135-147

Le secteur public connaît, ces dernières années, une profonde et sérieuse remise en question. Nombreux sont ainsi les états où une politique générale de modernisation de la fonction publique est, ou va ... [more ▼]

Le secteur public connaît, ces dernières années, une profonde et sérieuse remise en question. Nombreux sont ainsi les états où une politique générale de modernisation de la fonction publique est, ou va être, instaurée. Au centre des préoccupations, le citoyen y bénéficie d’une place de choix: il fait l’objet de nombreuses attentions et peut donc désormais s’attendre à davantage d’égards. Qualité du service et satisfaction de la population deviennent en effet des concepts clés de la fonction publique. Pour atteindre ces objectifs, c’est toute la conception des relations qu’entretiennent citoyen et secteur public qui est revue. Les technologies de l’information et de la communication (TIC) présentent, dans ce cadre, de nombreux atouts. L’interface citoyen - secteur public s’en trouve modernisé avec, comme objectif avoué, une proximité accrue avec la population pour une plus grande satisfaction de celle-ci. Si ce recours aux TIC offre d’indéniables opportunités - tant en termes d’innovation de services que dans la manière dont ceux-ci sont prestés -, il n’en soulève pas moins certaines questions, l’accès aux services étant, pour le citoyen, complètement revu. Sur base d’une analyse critique de la littérature et de l’étude d’un cas concret, notre contribution entend questionner l’implémentation et la gestion des TIC dans l’interface citoyen - fonction publique. [less ▲]

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See detailIs laparoscopy still the gold standard in infertility assessment? A comparison of fertiloscopy versus laparoscopy in infertility. Results of an international multicentre prospective trial: the 'FLY' (Fertiloscopy-LaparoscopY) study.
Watrelot, A.; NISOLLE, Michelle ULg; Chelli, H. et al

in Human Reproduction (2003), 18(4), 834-9

BACKGROUND: The aim of this prospective multicentre study was to compare the two endoscopic techniques of laparoscopy and fertiloscopy in routine evaluation of the pelvis in infertile women. METHODS: A ... [more ▼]

BACKGROUND: The aim of this prospective multicentre study was to compare the two endoscopic techniques of laparoscopy and fertiloscopy in routine evaluation of the pelvis in infertile women. METHODS: A total of 92 women was selected in 14 University Hospitals to undergo fertiloscopy followed by transabdominal laparoscopy by a team of two surgeons in each hospital. RESULTS: A high degree of concordance was observed between these two techniques, in that if fertiloscopy did not detect any abnormalities, this was also confirmed by laparoscopy. Discordance was observed in similar numbers of cases: eight after laparoscopy and nine after fertiloscopy. The diagnostic index for fertiloscopy and laparoscopy was calculated; sensitivity (86 and 87% respectively) and negative predictive value (64 and 67% respectively) were similar. The kappa index was also calculated for each of the six structures/regions (right/left tube; right/left ovary; peritoneum of pouch of Douglas; posterior uterus), and concordance (0.78 to 0.91) was considered almost complete. CONCLUSIONS: These results confirm fertiloscopy as a minimally invasive safe procedure that may be considered as an alternative to diagnostic laparoscopy in the routine assessment of women without clinical or ultrasound evidence of pelvic disease. On the basis of the additional advantages of fertiloscopy, namely salpingoscopy or microsalpingoscopy, it is considered that fertiloscopy could replace laparoscopy as a routine procedure in such women. [less ▲]

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See detailDoes the Direction of Ductal Blood Flow Affect Regional Circulatory Hemodynamics in Duct Dependent Congenital Heart Disease?
Campbell, Morag; Rigo, Vincent ULg; Robertson, Murray

in Pediatric Research (2003, April), 53(4 Part 2/2), 471

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See detailAlimentation et cancer
Castronovo, Vincenzo ULg

in Revue Médicale de Liège (2003), 58(4), 231-9

The role of a qualitatively and quantitatively altered nutrition for the development of cancer in human is largely recognized. While the human life expectancy is continuously expanding and the World ... [more ▼]

The role of a qualitatively and quantitatively altered nutrition for the development of cancer in human is largely recognized. While the human life expectancy is continuously expanding and the World Health Organization is predicting a dramatic rise in the number of patients that will get cancer and die from it in the next decades, it is useful to attempt to understand the real impact of nutrition at the level of the oncogenesis mechanisms. Oxidative stress, methylation deficit and imbalance in the ratio of omega-3 and omega-6 fatty acids represents situations directly linked to nutrition and which contribute to an increased risk for cancer development. The understanding of the mechanisms by which nutrition affects these processes should better stimulate health professionals to consider with more attention what their patients are eating. [less ▲]

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See detailGPs working in solo practice : obstacles and motivations for working in a group ? A qualitative study
Feron, Jean-Marc; Cerexhe, F.; Pestiaux, Dominique et al

in BMC Family Practice (2003), 20(2), 167-172

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See detailEffects of a progestogen on normal human breast epithelial cell apoptosis in vitro and in vivo
Desreux, Joëlle ULg; Kebers, F.; Noël, Agnès ULg et al

in Breast (Edinburgh, Scotland ) (2003), 12(2), 142-149

Many investigators have reported cyclic proliferation of normal human breast epithelial cells. A delicate balance between proliferation and apoptosis (programmed cell death) ensures breast homeostasis ... [more ▼]

Many investigators have reported cyclic proliferation of normal human breast epithelial cells. A delicate balance between proliferation and apoptosis (programmed cell death) ensures breast homeostasis. Both the follicular and luteal phases of the menstrual cycle are characterized by proliferation, whereas apoptosis occurs only at the end of the latter phase. In this study, we observed that the withdrawal of a synthetic progestin (nomegestrol acetate or NOMAC), but not continuous treatment with it, induced apoptosis of normal human breast epithelial cells in vitro and in women who applied NOMAC gel to their breasts. Furthermore, this apoptotic response was specific to normal breast cells, since withdrawal of NOMAC did not induce apoptosis of tumoral T47D cells in vitro or of fibroadenoma cells in women. These observations open up new perspectives in the prevention of hyperplasia and breast cancer. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailImpact of the joint space width measurement method on the design of knee osteoarthritis studies.
Bruyère, Olivier ULg; Henrotin, Yves ULg; Honore, Aline et al

in Aging Clinical & Experimental Research (2003), 15(2), 136-41

BACKGROUND AND AIMS: Recent guidelines recommend measurement of articular loss over several years, determined by conventional X-rays, as the principal outcome measure in clinical trials of potential ... [more ▼]

BACKGROUND AND AIMS: Recent guidelines recommend measurement of articular loss over several years, determined by conventional X-rays, as the principal outcome measure in clinical trials of potential structure-modifying drugs in osteoarthritis (OA). The aim of this study was to assess the impact of the joint space width measurement method on sample size calculation in knee OA studies. METHODS: Standard knee X-rays were taken in 212 patients with knee OA at baseline and after 3 years of follow-up. Mean joint space width (JSW) was measured with an in-house computer-assisted method. Minimum JSW, measured with a graduated magnifying lens, was taken as external standard. After calculation of the intra- and inter-observer reproducibility of the JSW, sensitivity to change was assessed using the standardized response mean (SRM). The number of patients needed to identify a mean significant difference of 0.5 mm in joint space narrowing between the placebo and the treated group, after 3 years of follow-up, was then calculated. RESULTS: JSW measured with the computer-assisted technique showed better intra- and inter-observer reproducibility than when using the magnifying lens. JSW values measured with our computer-assisted method were significantly correlated with JSW values obtained using the magnifying lens (r=0.87, p<0.001). The SRM were 0.44 and 0.40 for the computer-assisted method and magnifying lens, respectively. The number of patients needed was 131 per group using the computer-assisted method, and 104 using the magnifying lens. CONCLUSIONS: Our method of measurement of JSW may be of potential use in longitudinal studies evaluating the effect of structure-modifying drugs in OA, due to its high level of precision and efficiency. However, although sensitivity to change is markedly better with the digitized method compared with the graduated magnifying lens, we recommend the measurement of mean and minimum JSW in structure-modifying OA trials. [less ▲]

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See detailPrevention primaire et secondaire du cancer colorectal
Polus, Marc ULg; Piront, Patricia ULg; Jerusalem, Guy ULg et al

in Revue Médicale de Liège (2003), 58(4), 247-53

Colorectal cancer is really a public health problem. The authors review the literature about the environmental factors leading to colorectal cancer. Chemoprevention of colorectal cancer is also discussed ... [more ▼]

Colorectal cancer is really a public health problem. The authors review the literature about the environmental factors leading to colorectal cancer. Chemoprevention of colorectal cancer is also discussed, particularly by aspirin and non steroidal anti-inflammatory drugs. Development of specific cyclooxygenase-2 inhibitors constitutes a promising research's field. Secondary prevention by coloscopy and polypectomy must lead to a lower rate of colorectal cancer disease and improvement of mortality. [less ▲]

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See detailSound-producing mechanisms and recordings in Carapini species (Teleostei, Pisces)
Parmentier, Eric ULg; Vandewalle, Pierre ULg; Lagardere, Jean-Pierre

in Journal of Comparative Physiology A-Neuroethology Sensory Neural and Behavioral Physiology (2003), 189(4), 283-292

Carapus boraborensis, C. homei and Encheliophis gracilis are three species of Carapidae that display the ability to penetrate and reside in the holothurian Bohadschia argus. This study describes both the ... [more ▼]

Carapus boraborensis, C. homei and Encheliophis gracilis are three species of Carapidae that display the ability to penetrate and reside in the holothurian Bohadschia argus. This study describes both the particular morphology of the sound-producing structures and, for the first time, the sounds produced by each species. The study of the structures composing the sound-producing system seems to indicate that the action made by the primary sonic muscles (i.e. the pulling and releasing of the front of the swim bladder) might be responsible for the sound emissions of these three species by provoking a vibration of a thinner zone in front of the swim bladder (swimbladder fenestra). The sounds were only emitted and recorded when several individuals of the same species were inside the same sea cucumber. They were composed of serially repeated knocks and were heard as drum beats or drum rolls. Their specific differences were mainly defined as variations in the timing or grouping of the knocking sounds. The recordings of these sound productions demonstrate a vocal ability for the three species, linked with the presence of particular organs associated with sound production. Moreover, the ecological significance of the sounds and of the sound apparatus system is discussed. [less ▲]

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