Showing papers by "University of Mons published in 1992"
TL;DR: In this paper, a study of the convection in acetone due jointly to the thermocapillary (Marangoni) and thermogravitational effects is presented, where the liquid (acetone) is submitted to a horizontal temperature difference.
Abstract: This paper presents a study of the convection in acetone due jointly to the thermocapillary (Marangoni) and thermogravitational effects. The liquid (acetone) is submitted to a horizontal temperature difference. Experiments and numerical simulations both show the existence of three different states : monocellular steady states, multicellular steady states and spatio-temporal structures. The results are discussed and compared with the linear stability analysis of Smith & Davis (1983).
145 citations
TL;DR: Thirty-three tournament-level young Belgian chess players aged 8 to 13 were tested with the French WISC and the results suggest that a high level of general intelligence and of spatial ability are necessary to achieve a high standard of play in chess.
Abstract: Thirty-three tournament-level young Belgian chess players aged 8 to 13 were tested with the French WISC (Wechsler Intelligence Scale for Children). The mean full scale IQ = 121, verbal IQ = 109 and performance IQ = 129. The results suggest that a high level of general intelligence and of spatial ability are necessary to achieve a high standard of play in chess. The high spatial ability of these young chess players suggested by the high performance IQs may go some way towards explaining why males tend to be more numerous than females among high-standard chess players.
96 citations
TL;DR: The experimental data indicate that the SMA could play an important role in the generation of the frontal N30 and to a lesser extent N23 because of the gating phenomenon when repeated fast finger movements on the stimulated side are mentally simulated.
94 citations
TL;DR: The major cause of bradykinesia was found to be depression in the rate of rise of electromyographic activity, and the amplitude of the peak of this activity did not change significantly.
Abstract: Parkinsonian bradykinesia is defined by a slowness in the execution of movement. We studied the pathophysiology of this symptom in rapid arm-reaching movements to a visual target carried out in a reaction-time task. The major cause of bradykinesia was found to be depression in the rate of rise of electromyographic activity. The amplitude of the peak of this activity did not change significantly. There was no change either in the sequential activation of muscles, in the amount of co-contraction activity, in the accuracy of aim toward the visual target, or in the movement trajectory.
83 citations
TL;DR: The valence-electronic density of states (DOS) calculated is found to be in excellent agreement with the high-resolution energy-distribution curves obtained from synchrotron-photoemission experiments in terms of both positions and relative intensities of the peaks.
Abstract: Based on the geometries optimized by the AM1 semiempirical technique (Austin Model 1 of Dewar et al.), we exploit the valence-effective-Hamiltonian (VEH) method to study the electronic structures of ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$. The valence-electronic density of states (DOS) calculated is found to be in excellent agreement with the high-resolution energy-distribution curves obtained from synchrotron-photoemission experiments in terms of both positions and relative intensities of the peaks. The maximum difference in peak position between theory and experiment is 0.4 eV. This shows that the VEH method provides a very reasonable description of these two fullerenes. We then apply the VEH-SOS (sum-over-states) approach to study the nonlinear optical response of ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$. We obtain that the off-resonance third-order susceptibility ${\mathrm{\ensuremath{\chi}}}^{(3)}$ is on the order of ${10}^{\mathrm{\ensuremath{-}}12}$ esu. Our results are fully consistent with the electric-field-induced second-harmonic generation and third-harmonic-generation (THG) measurements by Wang and Cheng and the degenerate-four-wave-mixing measurements by Kafafi et al., but about three to four orders of magnitude lower than the data reported by Blau et al. and by Yang et et al. The static ${\mathrm{\ensuremath{\chi}}}^{(3)}$ values of ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$ are compared to those of polyacetylene. We also investigate the dynamic nonlinear optical response by calculating the THG spectrum. We find that the lowest two-photon and three-photon resonances occur at almost the same frequency for ${\mathrm{C}}_{60}$, because of the symmetry of the molecule.
66 citations
01 Dec 1992-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The Barrel Ring Imaging CHerenkov (BRICH) detector as mentioned in this paper is a photoensitive gas-filled drift chamber where the photoelectrons drift to a MWPC of special construction.
Abstract: A short explanation is given of the Barrel Ring Imaging CHerenkov (BRICH) detector and its performance. We discuss in brief some of the requirements to run this detector. Special attention is paid to the functioning of the Cherenkov photon detector — a photosensitive gas-filled drift chamber where the photoelectrons drift to a MWPC of special construction. We illustrate the BRICH performance with some preliminary results.
61 citations
TL;DR: The size of a sexually mature individual is more a function of its past history in the meadow than of its real age, and the ability of H. tubulosa to grow more efficiently in areas of low water turbulence where Posidonia shoots are scattered and detrital food is more easily accessible.
Abstract: . Holothuria tubulosa individuals were sampled regularly at three different depths (6, 19, and 33m) over a 20-month period in a Posidonia oceanica meadow off Ischia Island (Italy). Biometrical analysis demonstrated that holothuroids have a well-marked size-related distribution according to depth, with the smallest individuals in the shallowest part of the meadow and the large ones in its deepest part. The observed distributions reflect the ability of H. tubulosa to grow more efficiently in areas of low water turbulence where Posidonia shoots are scattered and detrital food is more easily accessible. Recruitment takes place in the shallow meadow, and holothuroids with high reproductive potential only occur in the deep meadow. Small holothuroids (shallow individuals of similar sizes) may be either juveniles or sexually mature individuals; environmental constraints apparently restrict the growth of individuals and their gonads. There is a progressive downward migration of growing individuals when the whole population is considered, although at the level of the individual the migration occurs randomly. Accordingly, the size of a sexually mature individual is more a function of its past history in the meadow than of its real age.
54 citations
TL;DR: The choice of restriction enzyme was found to influence the number of bands, the value of the index of similarity and the probability of obtaining an identical fingerprint between unrelated individuals, and the desirability of determining the optimal experimental conditions as a preliminary to any behavioural or population genetic studies that use the multilocus DNA fingerprinting methodology.
Abstract: Multilocus profiles were investigated in five different species of Galliformes (ring-necked pheasant Phasianus colchicus, Indian peafowl Pavo cristatus, Japanese quail Coturnix coturnix japonica, domestic chicken Gallus gallus, and red grouse Lagopus lagopus scoticus) using two human multilocus probes (33.6 and 33.15) in combination with each of four restriction enzymes (AluI, DdeI, HaeIII or HinfI). All the species show a DNA fingerprint-like pattern using at least one restriction enzyme in combination with each multilocus probe. The number of bands detected and the value of the index of similarity for each species differ significantly between the profiles obtained with each multilocus probe. Some enzyme/probe combinations reveal strong cross-hybridization of the multilocus probes with satellite or satellite-like DNA sequences in pheasant, peacock, quail and chicken, which partially or completely prevented scoring of the profile. The choice of restriction enzyme was found to influence the number of bands, the value of the index of similarity and the probability of obtaining an identical fingerprint between unrelated individuals. The Mendelian inheritance and independent segregation of the fragments detected using AluI was investigated in three species (ring-necked pheasant, Indian peafowl and red grouse). Some bands were shown to be tightly linked. An extreme case was encountered in the red grouse, where 12 of the 15 bands scored in one parent represented only two, apparently allelic, haplotypes and so derived from a single locus. However, fingerprint patterns will often be adequate for use in paternity analyses, such as in behavioural studies, despite the occurrence of haplotypic sets of bands. Identical DNA multilocus profiles were sometimes observed between captive-bred siblings in one species. These results emphasize the desirability of determining, in each new species, the optimal experimental conditions as a preliminary to any behavioural or population genetic studies that use the multilocus DNA fingerprinting methodology.
51 citations
TL;DR: Three weeks after treatment with gentamicin, morphological evidence of drug-induced injury had disappeared due to the tissue repair process, except for the occasional presence of small hyperplastic foci in renal cortex interstitium.
Abstract: Aminoglycoside antibiotics act as nephrotoxic drugs, inducing a lysosomal phospholipidosis and necrotic lesions essentially in convoluted proximal tubules. Previous studies have demonstrated that tubular injury caused by these compounds elicits a process of renal tissue repair (tubular regeneration) involving an increase of cell turnover in tubular epithelium. The present study was performed in order to: (i) achieve further insight into the temporal relationship between aminoglycoside-induced phospholipidosis, tubular necrosis, and tubular regeneration; and (ii) approach the control of tubular regeneration after nephrotoxin-induced insult. To investigate the latter point, we examined by immunocytochemistry the intrarenal distribution of epidermal growth factor (EGF) during tubular regeneration. Five groups of female Sprague-Dawley rats (n = 5) were treated for 4 days with gentamicin i.p. at a daily dose of 50 mg/kg delivered in 2 injections per day. Sham-treated animals (n = 5) received an equivalent amount of vehicle (0.9% NaCl) according to the same protocol. Groups of treated rats, and controls, were terminated 16 h (day 1), 4 days, 7 days, 14 days, and 21 days after the end of gentamicin administration. One hour prior to necropsy, each animal was given an i.p. injection of 40 mg 5-bromo-2'-deoxyuridine (BrdU) for the immunocytochemical demonstration of S-phase cells, using an anti-BrdU monoclonal antibody. Renal tissue was processed for light microscopy analysis, namely: a computer-aided morphometry of lysosomes in proximal tubular cells, a single-blind evaluation of gentamicin-induced tubular injury, the measurement of cell proliferation by immunocytochemical detection of BrdU-labeled nuclei, the demonstration of EGF-like immunoreactive material in renal tissue by using anti-rat EGF antiserum and immunogold-silver staining. As revealed by the morphometry of lysosomes in proximal tubular epithelium, the degree of gentamicin-induced phospholipidosis was maximum at day 1 (relative area occupied by lysosomes was increased 25-fold over mean control value) and declined thereafter. In contrast, tubular necrosis reached a peak 4 days after the end of drug administration. In proximal tubular epithelium, the stimulation of cell turnover associated with tubular regeneration showed a peak at day 7 (15-fold the mean control value). Tubular regeneration was also accompanied by mild interstitial hyperplasia. Three weeks after treatment with gentamicin, morphological evidence of drug-induced injury had disappeared due to the tissue repair process, except for the occasional presence of small hyperplastic foci in renal cortex interstitium. In both treated animals and controls, EGF immunoreactivity as revealed by immunocytochemical staining was associated with distal tubules (renal cortex and outer medulla).(ABSTRACT TRUNCATED AT 400 WORDS)
50 citations
01 Jan 1992
TL;DR: Drugs used for attenuating alcohol intake consist of two types: agents postulated to attenuate drinking by causing aversive consequences if alcohol is consumed after they are ingested, including disulfiram.
Abstract: Drugs used for attenuating alcohol intake consist of two types:
1.
Agents postulated to attenuate drinking by causing aversive consequences if alcohol is consumed after they are ingested, including disulfiram.
2.
Agents postulated to attenuate directly the desire to drink, including such drugs as lithium, fenfluramine, zimelidine and bromocriptine.
50 citations
TL;DR: In this paper, it was shown that soliton-like charge storage configurations are formed in β-carotene upon p-doping by intermolecular charge transfer, and the charge storage states are characterized by a single-intragap absorption band, by zero spin, and by significant structural (bond length) relaxation.
TL;DR: In spontaneous speech, the formants values show a marked schwa-tendency and increasing intra-cluster variability, which result in lowered differenciation of the sounds in spontaneous speech.
TL;DR: In this paper, seven unambiguous events out of a sample of 270 000 Z0 decays, contain in the same jet a Ds meson and a muon at large transverse momentum relative to the jet axis.
TL;DR: The static and dynamic second hyperpolarizability tensors of oligomers of polyacetylene, polyparaphenylene vinylene, and polythienylene Vinylene are evaluated by means of the valence effective Hamiltonian (VEH) method and the sum-over-states (SOS) approach is exploited.
Abstract: The static and dynamic second hyperpolarizability tensors of oligomers of polyacetylene, polyparaphenylene vinylene, and polythienylene vinylene are evaluated by means of the valence effective Hamiltonian (VEH) method The sum-over-states (SOS) approach is exploited, by constructing excited states from both single- and double-electron excitations The ab initio coupled perturbed Hartree-Fock method is also applied in the case of small representative molecules such as benzene, thiophene, styrene, and thienylethylene in order to test the validity of the VEH-SOS approach The VEH-SOS results are found to be comparable with the ab initio results The length dependence of the static hyperpolarizability is analyzed and found to scale with the optical gap evolution of the different oligomers The dynamic properties are presented in terms of third-harmonic generation and the dc Kerr effect
TL;DR: In this article, the search in DELPHI data for neutral Higgs bosons is described, and no candidate for the Standard Model Higgs is seen in Z0 decays to H 0 ν ν, H 0 μ + μ − or H 0τ+τ− after selections that proved efficient for finding simulated H0.
TL;DR: Bovine heart 6‐phosphofructo‐2‐kinase/fructose‐2,6‐bisphosphatase (PFK‐2/FBPase‐2) was phosphorylated by incubation with [γ‐32P]MgATP and cyclic AMP‐dependent protein kinases (PKA) or protein kinase C (PKC) and evidence for new phosphorylation sites for PKA and PKC was obtained.
TL;DR: In this paper, a review of ab initio calculations on organic molecules presenting promising quadratic nonlinear optical properties is presented, and the results provide a detailed understanding of the avilable experimental data.
Abstract: We present a review of ab initio calculations we recently performed on organic molecules presenting promising quadratic nonlinear optical properties. These molecules constitute so-called push–pull conjugated compounds in which a conjugated segment is capped at one end by an acceptor group and at the other end by a donor group. We foucs on three series of systems: (i) p-amino-p′-nitrodiphenylacetylenes for which “unusual” distorsion patterns have been recently reported; (ii) benzodithiapolyenals, which present among the largest second-order polarizabilities ever measured; and (iii) 2-methylene-2H-pyrrole derivatives. Our results are found to provide a detailed understanding of the avilable experimental data.
TL;DR: The lack of suckers and the coexistence of two adhesive cell types in the disc epidermis give the locomotory podia of H. forskali a “compromise” structure which would perhaps explain their ability to move as efficiently along soft and hard substrata.
Abstract: The ventral surface ofHolothuria forskali (Holothuroida, Aspidochirotida) is almost completely covered by small-sized podia that are locomotory Each podium consists of a stem that allows the podium to lengthen, to flex, and to retract, and this is topped by a disc that allows the podium to adhere to the substratum during locomotion Podia ofH forskali do not end in a sucker and their adhesion to the substratum thus relies entirely on the disc epidermal secretions The disc epidermis is made of five cell types: non-ciliated secretory cells of two different types that contain granules whose content is either mucopolysaccharidic (NCS1 cells) or mucopolysaccharidic and proteinic in nature (NCS2 cells), ciliated secretory cells containing small granules of unknown nature (CS cells), cilitated nonsecretory cells (CNS cells), and support cells The cilia ofCS cells are subcuticular whereas those ofCNS cells, although also short and rigid, traverse the cuticle and protrude in the outer medium During locomotion, epidermal cells of the podial disc are presumably involved in an adhesive/de-adhesive process functioning as a duogland adhesive system Adhesive secretions would be produced byNCS1 andNCS2 cells and de-adhesive secretion byCS cells All these secretions would be controlled by stimulations of the two types of ciliated cells (receptor cells) which presumably interact with the secretory cells by way of the nerve plexus The lack of suckers and the coexistence of two adhesive cell types in the disc epidermis give the locomotory podia ofH forskali a “compromise” structure which would perhaps explain their ability to move as efficiently along soft and hard substrata
TL;DR: In this article, the mass number dependence of charmed mesons was measured and α = 0.92±0.06 for charmed particles with 〈 x F 〉=0.24.
TL;DR: In this article, a slightly modified Frank's system of equations describing nucleation-controlled crystal growth is used to describe the curvature of polycrystalline polycrystals with rough surfaces.
TL;DR: It is found that a unilateral injection of a small amount of ketamine in the PH nucleus could cause either bilateral horizontal gaze holding failure or a vertical gaze hold failure or both an horizontal and a vertical gazing holding failure.
Abstract: The signal responsible for horizontal gaze holding is known to be generated, at least in part, by the prepositus hypoglossi (PH) nucleus, whereas that responsible for vertical gaze holding is known to be generated by the interstitial nucleus of Cajal (INC). An intramuscular injection of ketamine was recently demonstrated to induce a gaze holding failure. The aim of the present study was to analyse if ketamine produced this effect by acting, at least in part, on the PH nucleus. We found that a unilateral injection of a small amount of ketamine in the PH nucleus could cause either bilateral horizontal gaze holding failure or a vertical gaze holding failure or both an horizontal and a vertical gaze holding failure.
01 Mar 1992
TL;DR: In this paper, the electronic structure of poly(p -phenylene vinylene) (PPV) has been studied using ultraviolet photoelectron spectroscopy (UPS) and the experimental results are in excellent agreement with the results of model quantum chemical calculations based upon the valence effective Hamiltonian (VEH) method.
Abstract: The electronic structure of poly( p -phenylene vinylene) (PPV) has been studied using ultraviolet photoelectron spectroscopy (UPS). The experimental results are in excellent agreement with the results of model quantum chemical calculations based upon the valence effective Hamiltonian (VEH) method. The excellent agreement between theory and experiment enables a detailed description of the electronic structure, and the subsequent comparison of the present results with previous results in the literature.
TL;DR: This mechanism of ET-1 inactivation could play a role in acute inflammatory reaction where PMN adhere to the vascular endothelial cells and the peptide is destroyed by enzymatic hydrolysis.
TL;DR: In this article, modified neglect of diatomic overlap (MNDO) geometry optimizations and valence-effective Hamiltonian (VEH) band structure calculations on a new ladder-type polymer, poly[2,3,8,9]benzanthracene (PBA), were reported.
University of Oxford1, University of Trieste2, University of Padua3, University of Genoa4, Sapienza University of Rome5, Pierre-and-Marie-Curie University6, Moscow State University7, Tata Institute of Fundamental Research8, Stockholm University9, Tokyo Metropolitan University10, CERN11, University of Mons12
TL;DR: In this article, Bose-Einstein correlations among identically charged pions produced in collisions at 400 GeV/c were studied using the EHS spectrometer using the Kopylov-Podgoretskii parametrization.
Abstract: Bose-Einstein correlations among identically charged pions produced inpp collisions at 400 GeV/c are studied using the EHS spectrometer. Empoying the Kopylov-Podgoretskii parametrization, the average size of the emitting regionr
k and its lifetime τ for pion production were determined to ber
k=1.71±0.04 fm andcτ=0.89±0.05fm. The average sizer
g in terms of the Lorentz invariant Goldhaber parametrization was determined to ber
g=1.20±0.03fm. A decrease of the size with increasing momentum of the pions was observed. The size and the incoherence parameter of the pion emitting region were determined as a function of the charged particle multiplicity and the momentum of the pions. Identified charged kaons were used to study Bose-Einstein correlations among identically charged kaonsK
±K±. The average size of the emitting region for kaon production was determined to ber
k=1.87±0.33fm in terms of the Kopylov-Podgoretskii parametrization. A study of the influence of a reference sample is presented.
TL;DR: The degree of finite maximal codes over the alphabet {a, b} with at most 3 occurrences of the letter b in each word is characterized and all the indecomposable codes inside this family are described.
Abstract: In the framework of two Schutzenberger’s conjectures on codes, we characterize the degree of finite maximal codes over the alphabet {a, b} with at most 3 occurrences of the letter b in each word; it is strongly related to the number of factorizations of the code. We also describe all the indecomposable codes inside this family.
TL;DR: The decay modes D0→K−π+ K−K+, π−π+, K−π−π +π+ andπ+ have been studied by the hadroproduction experiment WA82 as mentioned in this paper.
TL;DR: In this article, a multi-step mechanism was proposed which incorporates these new experimental and theoretical data, and the case of methylated homologues of oxazole and isoxazole was considered.
Abstract: Molecular radical cations of oxazole (1) and isoxazole (2) dissociate by losing carbon monoxide or a hydrogen atom, respectively. These fragmentations were examined by use of tandem mass spectrometry, flash vacuum pyrolysis and ab initio molecular orbital calculations. A multi-step mechanism is proposed which incorporates these new experimental and theoretical data. The case of methylated homologues of 1 and 2 is also considered.
TL;DR: This article investigated gender differences in conversational behavior in an experimental setting and found that males' and females' conversational behaviour betrays more similarities than differences, contrary to what has often been claimed.
Abstract: We investigated gender differences in conversational behavior in an experimental setting. Twenty men and 20 women were randomly paired in 20 dyads and were asked to discuss a given topic. We examined the transcripts through a varied range of behavioral variables. First we analyzed the sequential ordering of utterances in order to establish the way male and female speakers take the floor and get involved in the sequence and topic structuring of dialogues. Second we coded the male and female utterances according to the language functions they expressed. Contrary to what has often been claimed, it was found that males' and females' conversational behavior betrays more similarities than differences. The discrepancies between these findings and those of previous studies are discussed relative to methodological and situational differences across studies