Showing papers by "University of Bordeaux published in 1986"

‘Terroirs’ and pedology of wine growing

Abstract: In the climate-soil-vine ecosystem it is difficult, when studying soil in isolation, to determine its influence on the constitution and the quality of grapes and wines. Moreover, human factors must be added to the natural factors, since the wine grower may happen to transform the characteristics and properties of the soil with soil conditioners, chemical manures and sometimes with irrigation. For any given mesoclimate, plant (rootstock and cultivar) and soil, he can, by means of training systems, modify the forwardness, quantity and quality of the harvest. Finally, technological factors are decisive as regards vinification, treatment and conservation of wines. Straightaway, it must be noted that there is no complete in-depth study of these ecosystems. This is because of the malay factors at work: climatic c o n d i t i o n s 9'1~176 the thermic and luminous microclimate of the exposed parts in relation to the training system ~2,~4,51'88'9~ the cultivar and the rootstock 85 the yield 4~ geographical and topographical factors s'67'8t'7~ soil cha rac t e r i s t i c s 23'27'36'48\"52'86'66'68'7z-74,82 mineral nutrition of the vine 3~,32,33 and especially nitrogen nutrition 17\" 18, 64 the hydric nutrition of the vine 8'15'23'24'26'28-3~ 76,78,79,81,84,92

Direct dating of the oxygen-isotope record of the last deglaciation by 14C accelerator mass spectrometry

Abstract: Major trends of Quaternary global climate are reflected in the continental ice volume changes which have been reconstructed by oxygen-isotope analysis1,2 δ18O records from deep-sea sediments show that the net glacial build-up occurs relatively slowly3, but that the end of an ice age occurs quickly, in less than 10,000 yr, implying a nonlinear response4,5 to simple Milankovitch theory6 The latter observation suggests that the cause of the most recent deglaciation was the maximum in summer calorific radiation at the upper latitudes of the Northern Hemisphere centred around 11,000 yr ago, a view supported by early studies7 Later work has produced conflicting dates, the main source of confusion being problems with obtaining accurate and reliable dates Here, by using accelerator mass spectrometry, we have measured 14C for various species of foraminifera to produce a reliable timescale for the oxygen-isotope record Our results show that, at the end of the last ice age, continental ice sheets began to melt more than 4,000 yr before the Northern Hemisphere maximum of summer calorific radiation

Melting history of Antarctica during the past 60,000 years

Abstract: Marked changes in the surface-water hydrology of the Southern Ocean during the past 60 kyr are revealed by a detailed comparison of the oxygen isotopic composition of planktonic and benthic foraminifera from sediment cores and the surface-water temperature estimated by a transfer function derived from the distribution of diatoms in the same sediments. From 35 to 17 kyr BP, the Southern Ocean polar front was covered by a melt-water lid containing a significant contribution from melting icebergs, calved from Antarctic ice shelves. These icebergs may have originated from a succession of surges of the ice shelves.

Evidence for two distinct calcium channels in rat vascular smooth muscle cells in short-term primary culture.

Abstract: Smooth muscle cells were isolated from rat portal vein and studied during short-term primary culture using the whole-cell patch-clamp technique. Two distinct types of Ca channel could be separated by studying the inward currents in Ba solutions. The rapidly inactivating current was present when cells were held at very negative potentials (−80 mV). This current was prominent for relatively small depolarizations and was insensitive to nifedipine. A slowly inactivating current, corresponding to the slow Ca current previously reported in smooth muscles, was observed at less negative holding potentials (−50 mV), was prominent for positive depolarizations and was blocked by low concentrations of nifedipine. Both currents were unaffected by tetrodotoxin and both were blocked by Co.

Differential immunocytochemical staining for glial fibrillary acidic (GFA) protein, S-100 protein and glutamine synthetase in the rat subcommissural organ, nonspecialized ventricular ependyma and adjacent neuropil

Abstract: Antibodies raised against glial fibrillary acidic protein (GFA), S-100 protein (S100) and glutamine synthetase (GS) are currently used as glial markers. The distribution of GFA, S100 and GS in the ependyma of the rat subcommissural organ (SCO), as well as in the adjacent nonspecialized ventricular ependyma and neuropil of the periaqueductal grey matter, was studied by use of the immunocytochemical peroxidase-antiperoxidase technique. In the neuropil, GFA, S100 and GS were found in glial elements, i.e., in fibrous (GFA, S100) and protoplasmic astrocytes (S100, GS). The presence of S100 in the majority of the ventricular ependymal cells and tanycytes, and the presence of GFA in a limited number of ventricular ependymal cells and tanycytes confirm the glial nature of these cells. The absence of S100, GFA and GS from the ependymocytes of the SCO, which are considered to be modified ependymal cells, suggests either a non-astrocytic lineage of these cells or an extreme specialization of the SCO-cells as glycoprotein-synthesizing and secreting elements, a process that may have led to the disappearance of the glial markers.

X‐Ray Photoelectron Spectroscopy of Palladium Fluorides

Abstract: X-ray photoelectron spectra of several Palladium fluorine compounds have been investigated. In all these phases Palladium atoms have a more or less distorted octahedral coordination. Satellite Structures generally occur in Pd 3d3/2 and Pd 3d5/2 levels and broad F 1s peaks are observed. Shifts in binding energies can be correlated with Palladium oxidation State and covalency. XPS results clearly confirm the unusual +III oxidation State of Palladium in NaPdF4, Na3PdF6, K3PdF6, and K2NaPdF6.

Selective Aerobic Degradation of Methyl-Substituted Polycyclic Aromatic Hydrocarbons in Petroleum by Pure Microbial Culturest

Abstract: Studies of laboratory degradation of Arabian light crude oil (b.p. < 200°C) by pure cultures of bacterial strains Pseudomonas sp. isolated from tanker ballast waters showed that biodegradation of alkyl-substituted polycyclic aromatic hydrocarbons strongly depends on the number, position, and the type of the substituents. Biodegradation of alkylphenanthrenes and dibenzothiophenes decreased with increasing number of substitutents. Biodegradation of methylphenanthrenes (P), dibenzothiophenes (DBT), pyrenes (Py) and chrysenes (C) showed a pattern similar to that previously observed for the methylnapthalenes; compounds containing unsubstituted α and β adjacent positions were more readily degraded. Thus, 2- and 3-MP, 2- and 3-MDBT, 1-MPy and 2- and 3-MC were shown to be less resistant to degradation within these families. Cycloalkylaromatics, such as partially aromatized steranes, hopanes and 8, 14-secohopanes were generally resistant to degradation by the cultures employed.

CVD-Processing of Ceramic-Ceramic Composite Materials

Abstract: Chemical vapor deposition (CVD), i.e. the deposition of a solid by a chemical reaction involving one or several gaseous chemical species and usually thermally activated, has been used for many years in different kinds of applications (e.g. oxidation or/and wear resistant coatings for cemented carbides, steels or alloys, preforms for drawing graded-index optical fibers, thin films for integrated circuits, coatings for nuclear fuels, etc...). In most cases, the substrates considered here have a rather simple shape and are made of non-porous materials.

Comparative uptake of gentamicin, netilmicin, and amikacin in the guinea pig cochlea and vestibule.

Abstract: The kinetics of the entry of three aminoglycosides into inner-ear tissues of the guinea pig after acute and chronic administration were compared: gentamicin toxic to the cochlea and the vestibule, amikacin preferentially cochleotoxic, and netilmicin of low ototoxic liability. During constant intravenous infusion, levels of the three drugs in plasma tended to reach a plateau after 1 h, while levels in perilymph did not reach a plateau within 6 h. The drug concentrations in both vestibular and cochlear tissues quickly reached saturation. Amikacin and gentamicin concentrations were similar in vestibular and cochlear tissues, while netilmicin values were somewhat lower. After 1 week of chronic treatment (100 mg of drug per kg of body weight daily subcutaneously), levels of gentamicin and amikacin in tissue were similar to each other and were not significantly different between cochlear and vestibular tissues. Netilmicin concentrations again were somewhat lower in the tissues, but identical to those of the other drugs in the perilymph. After 3 weeks of treatment, all of the drugs were equally distributed in the inner-ear tissues. Release of the drug from the tissues after the 3-week treatment was faster for amikacin (83% decrease after 20 days) than for netilmicin and gentamicin (approximately 50% decrease). There was no correlation, under any of the experimental conditions, between the drug concentrations and their degrees of toxicity. These results demonstrate that selective aminoglycoside ototoxicity cannot be explained by a preferential uptake or accumulation of drugs in the afflicted tissues or in the perilymph.

Enumeration of certain young tableaux with bounded height

Abstract: We consider Young tableaux strictly increasing in rows, weakly increasing in columns, and each column having an even number of elements. We show that the number of such tableaux with entries between 1 and n, and having at most 2k rows, is the product Open image in new window . The proof is mainly bijective, using configurations of non-crossing paths. At the end we need the qd-algorithm from Pade approximants theory.

Paleooceanography of the Mesogean sea based on ostracods of the northern Tunisian continental shelf between the late Cretaceous and early paleogene

Abstract: A new method analysis used in the study of the El Kef Section (north-western Tunisia) led to the paleooceanographic reconstruction of the Mesogean between-late Cretaceous and early Paleogene. Several changes observed are, in fact, worthy of particular mention: paleobathymetrically the area changed from an upper bathyal environment of about 400 m deep to an outer shelf domain of 100-50 m. Furthermore, the Oxygen Minimum Zone (O.M.Z.) became highly intense at (a) the Cretaceous-Tertiary transition (catastrophic event); (b) the P1-P2 boundary (intense thermic stratification); and (c) between P4 and P6 (very active paleoproductivity). In this last episode the continental shelf environment was subjected to intense upwelling responsible for the formation of a »prephosphatic« environment at water/sediment interface. The paleooceanographic history of phosphates in the Gafsa-Metlaoui basin is, in fact, in perfect stratigraphic and paleoenvironmental agreement with the paleobathymetric evolution of the Kef region. Finally, paleooceanographic communication between the Mesogean and the North Atlantic was, at this period, highly free because of lack of hydrologic relations between the North Atlantic and the Norwegian Sea.

On the involvement of the central cholinergic system in memory deficits induced by long term ethanol consumption in mice.

Abstract: Male mice of the BALB/c strain were given a solution of 12% v/v ethanol as their only source of fluid for 7 months. Memory performance was tested after ethanol was omitted from the diet for 3 to 9 weeks, and was compared with performance of control animals (no ethanol) which had been pair-fed or had received tap water. The spontaneous alternation task that was used consisted of two forced trials (acquisition) followed, at varying intervals ranging from 30 sec to 6 hr, by a free test trial (retention). Experimental subjects exhibited an accelerated rate of decay of spontaneous alternation, reaching chance level at 6 hours. All animals were then tested at this 6-hour interval following injections of either physostigmine or neostigmine that were given before both acquisition and retention (0.05 mg/kg IP). Results showed that physostigmine, but not neostigmine, dramatically improved performance of alcohol-treated subjects. Parallel neurochemical analysis showed that chronic ethanol treatment induced a slight (12%) but significant decrease in hippocampal sodium-dependent high affinity choline uptake. Though these findings suggest that the observed memory deficits (i.e., an accelerated rate of forgetting) might be related to a cholinergic dysfunction, alternative explanations are also proposed.

EPR of transition metal ions (Mn2+, Cu2+, Cr3+, Fe3+) in fluoroaluminate glasses

Abstract: EPR experiments have been performed on glasses related to the CaF2BaF2AlF3 system. Fluctuations of the EPR parameters are observed in the case of divalent ions which occupy distorted sites. The trivalent ions occupy sites of “fully rhombic” symmetry. A comparison with the EPR parameters obtained for crystallized α-CaAlF5 leads to the conclusion that the glass is built up by random type chains containing aluminium separated in various ways by the divalent cations, the coordination numbers of which may differ.

Stable expression of two variable surface glycoproteins by cloned Trypanosoma equiperdum.

Abstract: African trypanosomes are thought to evade the host immune system by periodically changing their variable surface glycoprotein (VSG). VSG genes are activated by a complex process involving the duplicative transposition of silent basic copy genes to one of several expression sites1–3. These expression-linked copies (ELCs) of the VSG genes are also subject to regulation within expression sites by as yet unknown mechanisms4–9. It is generally assumed that trypanosomes can express only one VSG gene at a time. Nevertheless, the finding that they contain multiple VSG gene expression sites suggests that multiple expression is possible. We show here that Trypanosoma equiperdum can stably express two VSG genes in a simple axenic culture system10 and that both antigens are present on the cell surface. The two antigens do not co-cap or form heterodimers. Their corresponding genes show no cross-hybridization and are situated in different telomere-linked expression sites. Northern blot analysis reveals that both genes are active in the double expressors.

Structural approach of the (xPbCl2-(1−x)Sb2O3) glass system

Abstract: A structural approach of xPbCl2, (1 − x)Sb2O3 glasses, quenched from the melt, is proposed. The crystallization process of the glasses is analyzed and a Raman scattering investigation is reported. The two investigations give valuable information on the structural arrangement of the glass network. Observations within the xPbCl2, (1 − x)Sb2O3 system show variations of local structure and a comparison is made with previously reported data for some Sb or As based glasses.

Computerized comparison of six adverse drug reaction assessment procedures.

Abstract: Several standardized assessment procedures are currently used in the evaluation of adverse drug reactions (ADRs). Disagreement in rating ADRs can result from between-raters variability and between-methods differences in weighting the evidence. We eliminated between-raters variability by computer simulation of 1134 ADRs (including all the possible combinations of criteria currently used) and by automatic rating using different algorithms adapted from six published methods. Percentage agreement (Po) and weighted kappa test (Kw) between pairs of methods are always better than with randomized scores, but the strength of agreement is only moderate (0.26 < Po < 0.59; 0.14 < Kw < 0.51). The weightings of criteria are evaluated in terms of sensitivity, specificity, and predictive values. Criteria are neither sensitive (0.41 < Se < 0.70) nor specific (0.18 < Sp < 0.63) and have poor predictive values. Disagreements on weightings are considerable for three major criteria: timing of event, dechallenge, and alternative etiologic candidates. We discuss some ways of improving reliability of ADR diagnosis. Clinical Pharmacology and Therapeutics (1986) 40, 451–461; doi:10.1038/clpt.1986.206

Vibrational modes in a one dimensional "quasi-alloy" : the morse case

Abstract: Effet d'un desordre deterministe sur la densite d'etats de vibration et les modes de vibration d'une chaine elastique a une dimension. Pour cette etude on utilise des sequences automatiques et des sequences engendrees par une substitution operant sur un alphabet a deux lettres

Organization of tyrosine-hydroxylase immunopositive neurons in the brain of the crested newt, Triturus cristatus carnifex.

Abstract: The localization of neurons, fibers, and terminals containing tyrosine hydroxylase (TH)-like immunoreactivity was studied in the brain of the crested newt by using an antiserum to rat phaeochromocytoma tyrosine hydroxylase. Immunoreactive cells and fibers were found in the spinal cord, the medulla oblongata (lateral periventricular areas), and the acousticolateral area. In the tegmentum mesencephali, two bilateral clusters of labelled cells were localized in the ventrolateral periventricular gray extending toward the caudal hypothalamus. In the hypothalamic tuberal lobes, the TH-like reactive neurons, frequently of CSF-contacting type, lined the dorsal wall of the lateral infundibular recesses. A thick network of TH-like reactive nerve fibers and terminals was observed in the perivascular zone of the median eminence and in the adenohypophysial pars intermedia. A number of labelled cell bodies were also found in the dorsal thalamus (pars intercalaris diencephali), the paraventricular organ, and the ventral wall of the preoptic recess. In the telencephalon, immunoreactive innervation was identified in the striatum, together with immunopositive cell bodies in the olfactory bulbs. The pattern of organization of TH-immunoreactive systems in the newt showed, except for some peculiarities (e.g., the labelled cell bodies in dorsal thalamus), close similarities to the arrangement typical of mammals.