Showing papers by "University of Bordeaux published in 1985"
TL;DR: In this paper, a combinatorial interpretation for any minor (or binomial determinant) of the matrix of binomial coefficients is given, involving configurations of nonintersecting paths, and is related to Young tableaux and hook length formulae.
825 citations
TL;DR: In this paper, the second-order Doppler shift contributes to the experimental isomer shift of 57Fe and a comparative study over a very large number of compounds is described.
601 citations
TL;DR: It is suggested that the tuning principle in noradrenergic systems is particularly important for the formation of associations and neural plasticity (interference control) and that the switching principle of dopaminergic systems modulates the timing, time-sharing and initiation of responses (program-control).
302 citations
TL;DR: In this paper, a structural model for the transition from the low-temperature ordered form (with brownmillerite structure) to the high temperature disordered form of perovskite structure has been explained in terms of microdomain formation.
147 citations
TL;DR: Immunogold staining was used to study the ultrastructural distribution of von Willebrand factor (vWF) in unstimulated platelets and found tubular structures located at the periphery of the alpha-granules closely resembled the internal tubular structure found in Weibel-Palade bodies.
133 citations
TL;DR: In this article, continuous swamp and lacustrine sequences from the northern edge of the Great Western Erg are dated at 9,300-3,000 yr BP, and the stable isotope composition of carbonates indicates that evaporation of groundwater supplies is responsible for these fluctuations in salt contents.
Abstract: Continuous swamp and lacustrine sequences from the northern edge of the Great Western Erg are dated at 9,300–3,000 yr BP. Diatoms, ostracods, molluscs and foraminifera show great changes in salinity, ranging from freshwater to marine-like environments. The stable isotope composition of carbonates indicates that the evaporation of groundwater supplies is responsible for these fluctuations in salt contents. Until now, evidence for the occurrence of a wet climatic phase of early and middle holocene age in the north-north-west Sahara was based on a restricted number of 14C dates from scattered lacustrine deposits and paleosols1–8. The present study complements this knowledge and highlights the importance of local hydrological factors in interpreting palaeolimnological changes.
120 citations
TL;DR: If the Ca-requiring neutral proteinases are involved in the meat ageing mechanism, it eems that the μmCa ANP is more likely to cause most of the post-mortem changes in the myofibrillar proteins, taking into account the low level of intracellular calcium.
111 citations
103 citations
TL;DR: In this article, a wide range of the fascinating physical properties of rare-earth borides is considered, including insulator-metal transitions, superconductivity, mixed-valence behaviour, magnetic phase transitions and thermoelectronic properties.
Abstract: During the last three decades a large interest has developed in the field of rare-earth borides. Six different families have been discovered: REB2, REB4, RE2B5, REB6, REB12 and REB∼66. Their extension is discussed, and it is shown on the base of both geometrical and electronic considerations how the RE atoms contribute to the stabilization of the electron-deficient boron framework. Attention has been devoted to the ability of metal or non-metal impurities either to stabilize a particular structure or to modify drastically the electrical and magnetic properties of the borides. A wide range of the fascinating physical properties of the rare-earth borides is considered, including insulator–metal transitions, superconductivity, mixed-valence behaviour, magnetic phase transitions and thermoelectronic properties.
103 citations
01 Jan 1985
102 citations
TL;DR: In this article, the hydrogen properties of a mechanically alloyed 2Mg + Ni mixture have been investigated and compared with those of the Mg2Ni alloy prepared by melting and sintering.
TL;DR: In this paper, le comportement asymptotique des solutions bornees des equations de la forme u t -Δη(u) dans Ω×R +, u(x,o)=u 0 (x) dan Ω,u (x,t)=u 1 (x andt) dlan ∂Ω×ρ +, ou Ω est un domaine borne de R N avec ∂ Ω de classe C 2, α, 0<α<1
Abstract: On etudie le comportement asymptotique des solutions bornees des equations de la forme u t -Δη(u)=f(x,u) dans Ω×R + , u(x,o)=u 0 (x) dans Ω,u(x,t)=u 1 (x,t) dans ∂Ω×R + , ou Ω est un domaine borne de R N avec ∂Ω de classe C 2, α, 0<α<1
TL;DR: The functional relationship between enkephalinergic and dopaminergic neurones at the level of the nucleus accumbens was investigated and may have important implications for the relation between dopamine dysfunction in mental illness and opiate addiction.
Abstract: In the present study the functional relationship between enkephalinergic and dopaminergic neurones at the level of the nucleus accumbens was investigated. The study consisted of two experiments in which dopaminergic (DA) transmission was chronically inhibited, and the behavioural locomotor response to intra-accumbens opiate injections analysed. First, specific 6-OHDA lesion of the DA-A10 neurones (either in nucleus accumbens or ventral tegmental area) was found markedly to increase the behavioural excitatory effects induced by nucleus accumbens injection of opioid peptides or morphine. Specific lesion of the central noradrenergic neurones had no such effect. Second, chronic pharmacological blockade of DA activity either with reserpine or a neuroleptic (pipothiazine palmitate) similarly induced a strong enhancement of the behavioral response to intra-accumbens opiate injection. The results are discussed in terms of novel mechanisms underlying denervation supersensitivity, and may have important implications for the relation between dopamine dysfunction in mental illness and opiate addiction.
TL;DR: Movement parameters and electromyographic studies were carried out in two macaque monkeys performing a rapid arm movement before and after administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).
TL;DR: It is shown that, in a free partially abelian monoid generated by a finite alphabet A, the subset [X∗] of A∗ containing all the words equivalent to a product of words of X is rational if X is a finite set of words.
TL;DR: In this paper, the ternary suicides RRh2Si2 (R Ce, Nd, Tb) and RRu2Si 2 (R Nd and Tb), with the tetragonal structure of the ThCr2 Si2 type, were investigated by neutron diffraction and magnetic measurements.
Abstract: Investigations by neutron diffraction and magnetic measurements are reported on the ternary suicides RRh2Si2 (R Ce, Nd, Tb) and RRu2Si2 (R Nd, Tb) with the tetragonal structure of the ThCr2Si2 type. CeRh2Si2 orders antiferromagnetically below 36 K with a wave vector k = [ 1 2 1 2 0] and magnetic moments parallel to the c-axis (m0) = 1.50 μ/Ce). The magnetic structure of TbRh2Si2 is antiferromagnetic (k = [001]) below TN = 94 K, the magnetic moments (8.5 μB/Tb at T = 15 K) are also parallel to the c-axis. NdRh2Si2 has the same magnetic structure below TN = 57 K, with m0 = 2.80 μB/Nd parallel to the c-axis. NdRu2Si2 exhibits a more complicated magnetic structure: below TN = 24 K it develops a sine-wave modulation (k = [0.130.130]) of the magnetic moments always parallel to the c-axis, with an amplitude Ak = 3.23 μB/Nd; a squaring of the magnetic structure occurs at about 15 K (m0 = 2.84 μB), and at T
TL;DR: In this article, the characterization of coke deposits on reforming catalysts has received little attention up to now, but it is shown that laser Raman spectroscopy can provide interesting information on these deposits, over a large range of carbon contents, and especially in the initial stages of coking.
TL;DR: In this paper, a cross-over from a fast diffusion regime to a diffusion-limited regime is discussed in relation to the one-dimensional crystal structure in the new material Li6Gd(BO3)3 Gd3+ ions.
TL;DR: A loss of hippocampal neurons was observed on histological sections from ethanol-treated mice, but the nucleus diameter, as well as the number of dendritic spines of the remaining neurons was not significantly affected by chronic ethanol consumption in the authors' experimental conditions.
Abstract: The effects of a 9-month period of ethanol consumption (followed by 3 or 6 months of withdrawal) on the hippocampus of mice were investigated. Compared with control animals, a loss of hippocampal neurons was observed on histological sections from ethanol-treated mice. This loss was greater in the ventral hippocampus (-18.6% to-18.7%) than in the dorsal hippocampus (-5.2% to-8.5%). However, the nucleus diameter, as well as the number of dendritic spines (studied using the Golgi-rapid impregnation) of the remaining neurons was not significantly affected by chronic ethanol consumption in our experimental conditions.
TL;DR: In this article, the authors investigated four recent soils and eleven soils buried under archaeological sites of known ages in an area between the Ghaggar Valley and the northern piedmont of the Arawalli Hills in northwestern India.
TL;DR: The data are interpreted as showing that long-term ethanol administration results in accelerated forgetting and increased vulnerability to proactive interference and, as such, they are compared to the memory dysfunctions observed in amnesic patients.
TL;DR: Results suggest that certain area 5 neurons may be involved in the linking of sensory inputs with motor outputs in monkeys, and Cerebrocerebellar loops may be a pathway in this linkage.
Abstract: The posterior parietal cortex (areas 5 and 7) in monkeys has been described as a higher association cortex and as such, area 5 has been attributed a complex somaesthetic function. More recently, a role in the formation of motor commands has been postulated for these two cortical areas. We have been particularly interested in the role area 5 neurons may have in movement initiation. Single neuron activity was recorded in area 5 during the performance of a trained forelimb movement in monkeys and neuronal responses which occurred prior to movement were observed. In the present report, we have examined the neuronal discharge data trial by trial using a technique of data analysis which enabled us to separate the changes in neuronal activity into stimulus- or movement-related responses. Both stimulus- and movement-related responses were identified. The stimulus-related responses were not simple sensory responses since they were also influenced by the timing of the onset of movement. These results suggest that certain area 5 neurons may be involved in the linking of sensory inputs with motor outputs. Cerebrocerebellar loops may be a pathway in this linkage. The latencies of the movement-related responses were such that corollary discharge from the motor cortex may have played a role in this activity. Such corollary discharge may be a form of information used by the animal to execute movement in the absence of peripheral feedback.
TL;DR: In this paper, the six families of binary rare-earth (RE) borides are reviewed: REB 2, REB 4, RE 2 B 5, REB 6 and REB ~66.
Abstract: The six families of binary rare-earth (RE) borides are reviewed: REB 2 , REB 4 , RE 2 B 5 , REB 6 , REB 12 and REB ~66 . The existence of these compounds and their crystal structures are discussed knowing that metal atoms contribute both geometrically and electronically to the stabilization of the electron-deficient boron framework. Emphasis is focused on the ability of metal or non-metal impurities either to stabilize a particular structure or to modify drastically the electrical and magnetic properties of the borides. Hexaborides are chosen to illustrate this point. The physical properties of some significant compounds are highlighted: ErB 4 and HoB 4 (magnetic phase transition), YbB 4 , YbB 12 and SmB 6 (intermediate-valence state), CeB 6 (dense Kondo-like behaviour), EuB 6 (ferromagnetic semiconductor), LaB 6 (thermoelectronic emitter) and YB 6 (superconductor).
TL;DR: In this paper, the properties of ZnO photoanodes doped with transition elements (Cr, Mn, Fe, Co, Ni) have been investigated for photodecomposition of aqueous solutions.
TL;DR: This paper will present the model which has allowed them to design a specific PMS organized into a hierarchy with a decentralized decision center.
01 Jan 1985
TL;DR: In this article, the problem of enumerating secondary structures of single-stranded nucleic acids (RNA, tRNA, etc.) having a given complexity was solved by using non-commutative variables.
Abstract: Many investigations in studying primary and secondary structures in Biology require theoretical statistical (that is enumerative) work. We solve one of these problems: enumerate secondary structures of single-stranded nucleic acids (RNA, tRNA, etc…) having a given complexity. This parameter has been introduced for energy computation purpose in order to predict the most stable secondary structure. The method relies on the (non-classical) use of non-commutative variables. Some orthogonal polynomials appear. The final solution shows a relationship between the parameter complexity and another parameter appearing in Hydrography and Botanic.
TL;DR: In this article, a nouveau procede pour realiser des pieces en materiau composite a matrice d'aluminium, renforce par des fibres a base de carbone, is presented.
Abstract: Utilisation d'un nouveau procede pour realiser des pieces en materiau composite a matrice d'aluminium, renforce par des fibres a base de carbone, ce procede etant directement derive de techniques de fonderie en alliage leger a basse pression
TL;DR: In this article, new fluorine fast ion conductors with tysonite-type structure have been obtained within the BiF31bBF2 (B = Ba, Pb) systems.
TL;DR: In this paper, the low-temperature magnetic susceptibilities and electrical resistivities of a new family of ternary suicides of general formula RMSi 3 are described, where R ≡ La or Ce and M ≡ Co, Rh, Ir, or Ru and Os crystallize in the BaNiSn 3 structure.
Abstract: The low-temperature magnetic susceptibilities and electrical resistivities of a new family of ternary suicides of general formula RMSi 3 are described. These compounds, where R ≡ La or Ce and M ≡ Co, Rh, Ir, or Ru and Os crystallize in the BaNiSn 3 structure. LaRhSi 3 and LaIrSi 3 are found to be superconducting with T c ∼- 2.5 K. In CeRhSi 3 and CeIrSi 3 , the Ce valence is close to 3 and these compounds are Kondo-lattice systems. An anomaly occurs in their susceptibilities at ∼-2 K and 5 K, respectively, accompanied by a sudden change from T to a T 2 regime in their resistivities. At the other end of the series, CeCoSi 3 behaves like a normal metal and becomes superconducting below T c ∼- 1.2 –1.4 K.
TL;DR: A commercial enzyme preparation of fungal origin (Trichoderma harzianum) contains a mixture of several β-d -glucanases as mentioned in this paper, and the major fraction is an exo-(1→3)-β-d-glucans enzyme having an isoelectric point of 7.8 and a molecular weight of ∼40,000.