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See detailA more thorough analysis of water rockets: Moist adiabats, transient flows, and inertial forces in a soda bottle
Gommes, Cédric ULg

in American Journal of Physics (2010), 78(3), 236-243

Although water rockets are widely used to illustrate first year physics principles, accurate measurements show that they outperform the usual textbook analysis at the beginning of the thrust phase. This ... [more ▼]

Although water rockets are widely used to illustrate first year physics principles, accurate measurements show that they outperform the usual textbook analysis at the beginning of the thrust phase. This paper gives a more thorough analysis of this problem. It is shown that the air expansion in the rocket is accompanied by water vapor condensation, which provides an extra thrust; the downward acceleration of water within the rocket also contributes to the thrust, an effect that is negligible in other types of rockets; the apparent gravity resulting from the acceleration of the rocket contributes as much to water ejection as does the pressure difference between the inside and outside of the rocket; and the water flow is transient, which precludes the use of Bernoulli’s equation. Although none of these effects is negligible, they mostly cancel each other, and the overall accuracy of the analysis is only marginally improved. There remains a difference between theory and experiment with water rockets. [less ▲]

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See detailMorfologia dell'empirico
Cigana, Lorenzo ULg

in Givigliano, Alfredo; Fadda, Emanuele (Eds.) Esercizi empirici. Filosofia, scienze, linguaggio (2013)

The epistemological relevance of the concept of "empirism" in Hjelmslev's Glossematics

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See detailMorire prima della fine d'agosto: la luce al termine della notte di Tristano
Curreri, Luciano ULg

in Dolfi, Anna (Ed.) I 'notturni' di Tabucchi (2008)

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See detailMoritella cold-active dihydrofolate reductase: Are there natural limits to optimization of catalytic efficiency at low temperature?
Xu, Y.; Feller, Georges ULg; Gerday, Charles ULg et al

in Journal of Bacteriology (2003), 185(18), 5519-5526

Adapting metabolic enzymes of microorganisms to low temperature environments may require a difficult compromise between velocity and affinity. We have investigated catalytic efficiency in a key metabolic ... [more ▼]

Adapting metabolic enzymes of microorganisms to low temperature environments may require a difficult compromise between velocity and affinity. We have investigated catalytic efficiency in a key metabolic enzyme (dihydrofolate reductase) of Moritella profunda sp. nov., a strictly psychrophilic bacterium with a maximal growth rate at 2degreesC or less. The enzyme is monomeric (M-r = 18,291), 55% identical to its Escherichia coli counterpart, and displays T-m and denaturation enthalpy changes much lower than E. coli and Thermotoga maritima homologues. Its stability curve indicates a maximum stability above the temperature range of the organism, and predicts cold denaturation below 0degreesC. At mesophilic temperatures the apparent K-m value for dihydrofolate is 50- to 80-fold higher than for E. coli, Lactobacillus casei, and T. maritima dihydrofolate reductases, whereas the apparent K-m value for NADPH, though higher, remains in the same order of magnitude. At 5degreesC these values are not significantly modified. The enzyme is also much less sensitive than its E. coli counterpart to the inhibitors methotrexate and trimethoprim. The catalytic efficiency (k(cat)/K-m) with respect to dihydrofolate is thus much lower than in the other three bacteria. The higher affinity for NADPH could have been maintained by selection since NADPH assists the release of the product tetrahydrofolate. Dihydrofolate reductase adaptation to low temperature thus appears to have entailed a pronounced trade-off between affinity and catalytic velocity. The kinetic features of this psychrophilic protein suggest that enzyme adaptation to low temperature may be constrained by natural limits to optimization of catalytic efficiency. [less ▲]

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See detailMorph switching in a dimorphic population of Triturus alpestris (Amphibia, Caudata)
Denoël, Mathieu ULg; Lena, Jean-Paul; Joly, Pierre

in Evolutionary Ecology (2007), 21(3), 325-335

The usual life cycle of Alpine newts comprises an aquatic larval stage and a terrestrial juvenile and adult stage. However, some populations differ from this pattern in exhibiting facultative ... [more ▼]

The usual life cycle of Alpine newts comprises an aquatic larval stage and a terrestrial juvenile and adult stage. However, some populations differ from this pattern in exhibiting facultative paedomorphosis where some individuals reach sexual maturity while retaining larval traits such as gills and gill slits. While paedomorphic newts can, in some circumstances, initiate metamorphosis, once a newt has commenced metamorphosis, the state is irreversible. Because the frequency of this switching from one morph to the other has never been quantified in the wild, we attempted to estimate switching rate and survival by carrying out a 3-year monitoring survey of a population inhabiting an alpine lake. While morph switching did occur in this population, it involved a relatively low proportion of the paedomorphs (approx. 12%), suggesting that metamorphosis is not favoured in the study population. The hypothesis of paedomorphic advantage was not supported since neither survival nor body condition differed between morphs. The ontogenetic pathway of wild Alpine newts is thus characterised by two forks in the developmental pathway. The first occurs during the larval stage (metamorphosis vs. paedomorphosis), and the second occurs in paedomorphic adults (switching for metamorphosis vs. continuation of the paedomorphic lifestyle). Such a two-level decision process may allow individuals to cope with environmental uncertainty. [less ▲]

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See detailMorphemes in the mind: Are there graded effects of semantic similarity on morphological processing in children?
Deacon, Hélène; Downing, Jennifer; Gonnerman, Laura et al

Conference (2010)

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See detailA morphic approach to combinatorial games : the Tribonacci case
Duchêne, Eric; Rigo, Michel ULg

in Theoretical Informatics and Applications. Informatique Théorique et Applications (2008), 42

We propose a variation of Wythoff's game on three piles of tokens, in the sense that the losing positions can be derived from the Tribonacci word instead of the Fibonacci word for the two piles game ... [more ▼]

We propose a variation of Wythoff's game on three piles of tokens, in the sense that the losing positions can be derived from the Tribonacci word instead of the Fibonacci word for the two piles game. Thanks to the corresponding exotic numeration system built on the Tribonacci sequence, deciding whether a game position is losing or not can be computed in polynomial time. [less ▲]

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See detailLes morphiniques
Roediger, Laurence ULg; Lamy, Maurice ULg

in Martin, C.; Viviand, X.; Pourriat, J. L. (Eds.) Sédation et analgésie en réanimation (1998)

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See detailLes morphinomimétiques en réanimation
Lamy, Maurice ULg; Joris, Jean ULg; Damas, Pierre ULg et al

in Revue Janssen-Cilag (1996)

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See detailLes morphinomimétiques en réanimation
Lamy, Maurice ULg; Joris, Jean ULg; Damas, Pierre ULg et al

in Réan urg (1993), 2(4bis), 488-494

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See detailMorpho-anatomy of the otic region in carapid fishes : eco-morphological study of their otoliths
Parmentier, Eric ULg; Vandewalle, Pierre ULg; Lagardère, Françoise

in Journal of Fish Biology (2001), 58

Carapid species are characterized by so-called otophysical structures (sonic muscles, broad first apophyses covering the anterior part of the swimbladder, etc.) The family includes pelagic (Pyramodon and ... [more ▼]

Carapid species are characterized by so-called otophysical structures (sonic muscles, broad first apophyses covering the anterior part of the swimbladder, etc.) The family includes pelagic (Pyramodon and Snyderidia) and benthic (Echiodon) species and ones that are either commensal with (Onuxodon, Carapus) or parasites of (Encheliophis) invertebrates (sea cucumbers, etc). The aim of the present work was to seek possible relationships between the structures of the inner ear (particularly the sagitta) on the one hand and otophysical structures and lifestyles within the Carapidae family. In the eight species studied, the otic cavity is wide, the saccular otosac and its sagitta are particularly developed. The sacculi touch each other on the median line. A comparison of the inner ear structures reveals notably that the species with the most developed sagitta and sacculus are those with the largest parapophyses and have a commensal or parasitic lifestyle. [less ▲]

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See detailMORPHO-BIOMETRIC CHARACTERIZATION OF TWO LOCAL CHICKEN BREEDS IN VIETNAM
Do Duc, Luc ULg; Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg et al

in The Role of Poultry in Improving Human Welfare (2012, September)

In Vietnam, 84% of the 188 million chickens are indigenous. The following local breeds are recorded: Ri, Mia, Te, Tau Vang, Ac, Oke, H’mong, Tre, Choi, Phu Lu Te, To, Dan Khao, Ho, Dong Tao and Van Phu ... [more ▼]

In Vietnam, 84% of the 188 million chickens are indigenous. The following local breeds are recorded: Ri, Mia, Te, Tau Vang, Ac, Oke, H’mong, Tre, Choi, Phu Lu Te, To, Dan Khao, Ho, Dong Tao and Van Phu. Mia, Ho and Dong Tao are reported as endangered or critical, while the Van Phu breed could have been lost during the last years. The phenotypes of the Mia and Ri breeds are described as quite close. The objective of this study is to characterize phenotypically Ri and Mia chickens. The morpho-biometric characterization was conducted according to the recommendation of FAO (1981). A total of 227 adults Ri (174 females and 53 males) and 53 adults Mia (18 males and 35 females) were used for the study. The following colors were observed for Ri and Mia respectively: tan (43.17% and 37.73%), gold salmon (24.23% and 26.42%), wheat (15.42% and 26.42%), dark red (9.69% and 5.66%), silver salmon (3.52% and 3.77%) and copper black (3.96% and 0%). Comb was mostly simple (91.19% and 100%) and red (100% and 100%) for both breeds. The wattles were of the same color as the comb while the color of the legs was yellow. The weights of adult males (2433.89g) and females (1752.86g) of the Mia breed were significantly higher than those of Ri (2053.02g and 1459.22g for males and females respectively). The results show that the external aspect of both breeds is not very different while body weights in the Ri breed were found lower than in the Mia breed. [less ▲]

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See detailMorpho-histology and genotype dependence of in vitro morphogenesis in mature embryo cultures of wheat.
Delporte, Fabienne; Pretova, Anna; du Jardin, Patrick ULg et al

in Protoplasma (2014)

Cellular totipotency is one of the basic principles of plant biotechnology. Currently, the success of the procedure used to produce transgenic plants is directly proportional to the successful insertion ... [more ▼]

Cellular totipotency is one of the basic principles of plant biotechnology. Currently, the success of the procedure used to produce transgenic plants is directly proportional to the successful insertion of foreign DNA into the genome of suitable target tissue/cells that are able to regenerate plants. The mature embryo (ME) is increasingly recognized as a valuable explant for developing regenerable cell lines in wheat biotechnology. We have previously developed a regeneration procedure based on fragmented ME in vitro culture. Before we can use this regeneration system as a model for molecular studies of the morphogenic pathway induced in vitro and investigate the functional links between regenerative capacity and transformation receptiveness, some questions need to be answered. Plant regeneration from cultured tissues is genetically controlled. Factors such as age/degree of differentiation and physiological conditions affect the response of explants to culture conditions. Plant regeneration in culture can be achieved through embryogenesis or organogenesis. In this paper, the suitability of ME tissues for tissue culture and the chronological series of morphological data observed at the macroscopic level are documented. Genetic variability at each step of the regeneration process was evaluated through a varietal comparison of several elite wheat cultivars. A detailed histological analysis of the chronological sequence of morphological events during ontogeny was conducted. Compared with cultures of immature zygotic embryos, we found that the embryogenic pathway occurs slightly earlier and is of a different origin in our model. Cytological, physiological, and some biochemical aspects of somatic embryo formation in wheat ME culture are discussed. [less ▲]

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See detailMorpho-Imaging : a veterinary website of anatomy and imaging
Noble, Prisca ULg; van Thielen, Bert; Verhelle, Filip et al

Conference (2011, July 07)

Introduction: The Morpho-Imaging website is based on an interactive multi-dimensional presentation of the anatomy and its relevant imaging. Its objective is to teach a practical approach of veterinary ... [more ▼]

Introduction: The Morpho-Imaging website is based on an interactive multi-dimensional presentation of the anatomy and its relevant imaging. Its objective is to teach a practical approach of veterinary anatomy that must be adapted to the clinician work. Methods: From domestic animals : imaging (Radiography, Magnetic Resonance Imaging, Computed Tomography and Echography) was performed and correspondant dissections (Osteology, Arthrology and Myology) were photographed. Morpho-Imaging and its content was produced using Adobe programs. It was hosted on the RVC1 multimedia platform and linked to the educational Philips iSiteTM Picture Archiving and Communication System (PACS) of the VUB5. Results: Morpho-Imaging consists of three major components named anatomy, imaging and pathological imaging. The pages are transversally and vertically connected with others, and always surmounted by a navigation bar with drop-down menus (DDM). The first DDM corresponds to the anatomy menu by species, the second and third DDMs correspond to the normal and pathological Imaging respectively. The Morpho-Imaging website is linked towards to WikiVet1 and the PACS5 by means of URL’s. Conclusion: The three dimensional viewing of anatomy and pathology is better presented using modern visualization tools and techniques, such as Volume Rendering Technique and Multi Planar Reconstruction. In addition, a real anatomic related atlas of multiple imaging sources is available for the users. Morpho-Imaging is a valuable tool used to challenge the cognitive process during training sessions of veterinary anatomy and imaging. [less ▲]

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See detailMorpho-structural analysis and mass movements Case study of Oued El Kaïm reservoir dam Nort-East Algeria
Draidia, Salah ULg; Havenith, Hans-Balder ULg; Benabbas, Chaouki

in Annual International Conference on Geological & Earth sciences_GEOS-2013 (2012, December)

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See detailMorphodynamic incidences of the trepanning of the endokarst by solution pipes. Examples of chalk caves in Western Europe (France and Belgium)
Rodet, Joël; Willems, Luc ULg; Brown, Joël et al

in Contributed Papers Proceedings 15th International Congress of Speleology (2009)

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See detailMorphodynamics of the Meuse River and its tributaries in the Ardenne Massif
Petit, François ULg

in Symposium pour la Protection de la Meuse (2004)

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See detailMorphodynamique des côtes et caractéristiques énergétiques de la houle étudiée grâce au SAR de ERS-1
Ozer, André ULg; Cornet, Yves ULg; Comhaire, A. L.

in Kaldeich, Brigite (Ed.) Proceedings of the First ERS1 Symposium "Space at the service of our environment" (1993)

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See detailMorphodynamisme d'un tronçon de la Loire bourbonnaise depuis le XVIIIe siècle
Leteinturier, B.; Engels, Patrick ULg; Petit, François ULg et al

in Géomorphologie : Relief, Processus, Environnement (2000)

Detailed reference viewed: 28 (15 ULg)