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Over the last several years, numerous outcrop localities have been revisited to add quantitative detail to submarine lobe facies models that previously focussed on facies relationships in a qualitative sense. This study utilises well‐exposed submarine lobe deposits of the Point Loma Formation in Cabrillo National Monument (San Diego, CA) to provide quantitative and statistical insights into the lateral variability of event‐bed (i.e. turbidite) architecture within and between lobe elements. Within a lobe element (defined as a surface‐bounded, genetically related package), event beds compensationally stack, thinning over subtle sea floor topography created by the previous event bed. Between lobe elements, larger‐scale compensation is observed, with clearly defined stratal surfaces and facies architecture distinguishing the four lobe elements. A lateral facies transition is observed for one lobe element, where sandstone beds pinch out and the element thickness halves over a distance of 100 m. However, architectural parameters of event beds (e.g. bed thickness, thinning rate, fining rate) are not appreciably different between these elements, suggesting that the observed stratal architecture does not readily translate into vertical bed thickness (i.e. stacking) patterns that could be easily recognised in common subsurface data types like borehole‐derived core. While the data derived from this outcrop study are valuable for improving the construction of realistic geological and reservoir models, caution is necessary when interpreting lobe element boundaries from borehole data. The lobe deposits measured in this study have event‐bed thicknesses and thinning rates most similar to semi‐confined proximal lobes, suggesting a more proximal position and more confined than previously interpreted. Based on the relationships between sandstone and mudstone thicknesses and thinning rates, bed and lobe‐element compensation and minimal evidence of erosion, the Point Loma Formation at Cabrillo National Monument is reinterpreted as a medial lobe environment with some degree of lateral and/or frontal confinement.

The late Miocene Messinian salinity crisis was an evaporitic episode that occurred throughout the Mediterranean; it concluded with a transition from hypersaline to fresher-water “lake sea” (Lago Mare) conditions prior to the Pliocene. Whereas numerous researchers propose that Lago Mare sediments accumulated in a Mediterranean-wide lake filled with Paratethyan waters, other workers reject this hypothesis. Here, to test this Paratethyan-overflow model, we develop a novel time-probabilistic approach to evaluate the distribution of precession-related deposits. We apply our methodology to 24 circum-Mediterranean sites, focusing on two previously untested parameters: the probability of preserving intrabasin precession cycles; and the similarities in interbasin preservation. Our results, which show an increase in preservation and similarity in successively younger cycles, display a trend opposite to what is expected from a flooded Mediterranean. Consequently, we conclude that Lago Mare accumulations were deposited in disconnected, shallow lacustrine environments, thereby casting doubt on the widely accepted Paratethyan-supply hypothesis.

Optimizing reservoir recovery relies on successfully transforming natural geological complexity into functional flow units that can be used to predict reservoir behavior. Stratigraphic connectivity and heterogeneity can be used to identify preferential flow-paths at different scales within a reservoir. Connectivity and heterogeneity are determined using well-established stratigraphic and reservoir-management methods, including amalgamation ratios, reservoir-quality indices, and Lorenz heterogeneities. Lorenz curves have a broad utility for defining permeability–porosity relationships among well-log and model datasets. Stratigraphic Modified Lorenz Plots (SMLP) are useful for defining quality-contribution rates for specific increments of depth to identify potential flow-risk elements. Different measures of reservoir quality (i.e., Reservoir Quality Indices) highlight heterogeneity distributions and identify potentially movable oil within flow units. Stratigraphic connectivity and heterogeneity concepts can be used to identify flow units, thief zones, baffles, barriers, or depleted regions that may not be obvious from traditional well-log or sand-flag analyses. Connectivity and heterogeneity workflows for porosity, permeability, saturation, and temperature properties are applied to a high-net fluvial reservoir system to illustrate how fine-scale stratigraphic heterogeneities impact flow within a heavy oil field. Although net-to-gross and related property flags are useful for identifying opportunities, subtle variations in sand quality may not be adequately captured by simple sand-flag analyses. Reservoir facies defined by heterogeneity and connectivity can guide well-path selection and improve predictions of reservoir behavior from field- to pattern-scale. Integrated connectivity and heterogeneity workflows enable opportunity identification for steamflooding and support heat-management plans by providing geologically consistent and objective measurements that can optimize or accelerate resource maturation in new and mature fields.

Constraining the avulsion dynamics of rivers and submarine channels is essential for predicting the distribution of sediment, organic matter, and pollutants in alluvial, deltaic, and submarine settings. We create a geometric channel-belt framework relating channel, levee, and floodplain stratigraphy that allows comparative analysis of avulsion dynamics for rivers and submarine channels. We utilize 52 channel-overbank cross-sections within this framework to provide avulsion criteria for submarine channels, and how they differ from rivers. Superelevation and a new channel-floodplain coupling metric are two key parameters that control channel-belt thickness in both rivers and submarine channels. While rivers only superelevate 1 channel depth above the floodplain prior to avulsion, submarine channels are more stable during aggradation, with superelevation values commonly > 3 channel depths. Additionally, channel-floodplain coupling in rivers is often weak, with floodplain aggradation negligible compared to channel aggradation, making rivers avulsion-prone. However, floodplain aggradation is more significant for submarine channels, resulting in stronger channel-floodplain coupling and thus a decreased potential for avulsion. The combination of enhanced superelevation and strong channel-floodplain coupling results in submarine channel-belts that can be as thick as ∼10 channel depths, while fluvial channel belts are limited to 2 channel depths. Submarine channels are more stable because turbidity currents have ∼50x lower density contrast between flow and ambient fluid as compared to rivers. This density contrast creates far less potential energy for avulsion, despite the much greater relief of submarine levees compared to fluvial levees. The modern Amazon submarine channel showcases this stability, with a channel belt that is ∼5 channel-depths thick for more than 400 streamwise km, which is more than twice the superelevation that a river is capable of. We interpret that enhanced floodplain aggradation and levee aggradation (and thus superelevation) in submarine channel belts are promoted by unique submarine flow characteristics, including turbidity current overspill, flow-stripping, and hemipelagic processes. We emphasize that rivers and submarine channels display very different avulsion dynamics and frequencies, profoundly affecting the stratigraphic architecture of channel-belt and downstream distributary deposits.

An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were Bacteroidetes and, to a lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary.

Resume L’utilisation massive d’antibiotiques a large spectre favorise l’emergence de bacteries multiresistantes. Objectifs. – Les objectifs de ce travail ont ete d’etudier les modes d’utilisation des antibiotiques et d’etablir la correlation entre les prescriptions d’antibiotiques et les recommandations dans une unite de soins intensifs neonatals. Materiel et methodes. – Il s’agit d’une etude prospective incluant pendant 6 mois tous les nouveau-nes admis en reanimation et recevant un traitement antibiotique. Les donnees recueillies comprenaient les indications, les criteres de decision d’antibiotherapie, la duree du traitement et le motif d’arret. La correlation prescription–recommandation etait jugee a posteriori par un medecin non prescripteur. Cent seize nouveau-nes ont ete inclus dont neuf avaient recu un traitement antibiotique a plusieurs reprises. L’âge gestationnel moyen etait de 33,5 semaines d’amenorrhee (SA). Dans 82 % des cas, le motif d’hospitalisation etait une detresse respiratoire. Resultats. – Les indications principales du traitement antibiotique etaient : l’infection primaire (78 %), l’infection nosocomiale (17 %), la prophylaxie postoperatoire (5 %). L’infection primaire etait dominee par la suspicion d’infection maternofœtale (SIMF) : 96 %. Dans 49 % des cas, la SIMF n’etait pas confirmee justifiant l’arret du traitement dans les 3 jours suivant son instauration. Soixante pour cent des infections nosocomiales concernaient des nouveau-nes de moins de 28 SA. Les criteres bacteriologiques ne jouaient un role decisionnel que dans les infections nosocomiales. La non observance des protocoles recommandes representait 9 % des enfants traites et concernait majoritairement une duree excessive de traitement. Conclusion. – Ces resultats montrent : 1) une majorite d’indication d’antibiotiques pour SIMF non confirmee ; 2) un faible taux d’infections nosocomiales ; 3) des infections nosocomiales principalement chez les grands prematures ; 4) moins de 10 % de non observances des protocoles. Cette etude montre la necessite d’etablir en reanimation neonatale des protocoles de traitements antibiotiques avec des criteres plus precis et de les evaluer regulierement.

Hypoxic events are common in newborns but their consequences on brain development have not been demonstrated. It has been reported that in newborn animal models of cerebral hypoxic-ischaemic insult, short-term hypoxia before the insult completely prevented brain damage. The mechanisms of this brain tolerance have not been fully elucidated. Using a rat model of hypoxic preconditioning at day 6 followed by carotid ligation and hypoxic insult at day 7, we found a decrease in the number of apoptotic cells 24 and 48 h after the insult in the striatum, hippocampus and cortex. We demonstrated here that regulation of apoptotic cell death is one of the mechanisms involved in tolerance to hypoxia-ischaemia induced by hypoxic preconditioning.

Resume Une infection neonatale tardive peut reveler une contamination pernatale, mais elle est le plus frequemment secondaire a une transmission postnatale. Observation. – Un premature ne apres 29 semaines d’amenorrhee a developpe une staphylococcie pulmonaire a 18 j de vie. Le profil electrophoretique de l’ADN de la souche de staphylocoque dore impliquee etait identique a celui de la souche de S. aureus retrouvee chez la mere 48 h avant l’accouchement, tout en etant different de ceux des souches responsables de colonisation d’autres enfants dans le service pendant la meme periode. Conclusion. – L’observation rapportee correspond a une infection nosocomiale probablement secondaire a une transmission maternelle per- ou postnatale.

Resume Nous avons realise une etude cas–temoins sur une periode de six ans et demi, pour rechercher les facteurs de risque d'enterocolite ulcero-necrosante (Ecun). Population et methodes – Appariement des cas d'Ecun confirmee a des temoins d'âge gestationnel et de periode d'hospitalisation identiques ; les apnees-bradycardies ont ete prospectivement denombrees. Resultats – Quarante-cinq cas et 89 temoins. Etaient associes a l'Ecun : le retard de croissance intra-uterin identifie avant la naissance (OR = 3,65, intervalle de confiance a 95 % (IC 95 %) : 1,54–8,63) ; un poids de naissance e tiercile (OR = 4,54, IC 95 % : 1,29-15,93), ou severes ≥ 3 e tiercile (OR = 6,15, IC 95 % : 1,59–23,75) ; une hemoglobinemie la plus basse ≤ 1 er tiercile (OR = 5,90, IC 95 % : 1,20–20,13) ; l'epaississement du lait par Gumilk ® (OR = 2,78, IC 95 % : 1,11–6,90). Conclusion – Les facteurs anoxo-ischemiques de la premiere semaine ne representent pas un risque important d'Ecun ; notre etude invite a etre prudent pour les indications de la triple antibiotherapie et vigilant pour la prise en charge des apnees-bradycardies.

Resume Objectifs – Etudier le devenir medical, le developpement cognitif et affectif des grands prematures a l'âge de quatre ans. Population et methode – Les enfants d'âge gestationnel inferieur a 33 semaines, nes entre 1992 et 1994, non handicapes et apparies a deux temoins nes a terme, ont beneficie a l'âge de quatre ans d'une evaluation complete, avec tests neuropsychologiques, du Kaufman-Assessment Battery (K-ABC) for Children, de Conners et du Profil Socio Affectif (PSA). Resultats – Les prematures se distinguaient des temoins par une taille plus petite ( p p = 0,027), une scolarite en premiere section de maternelle (44 % versus 27,6 %, p = 0,05), la capacite a dessiner un bonhomme (55,3 % versus 93 %, p p p = 0,0006, odds-ratio 33,2), un score de competence sociale du PSA inferieur a 45 ( p = 0,004, odds-ratio 35,9). Conclusion – Un suivi systematique des grands prematures doit s'accompagner d'une prise en charge precoce des enfants a probleme.

Two protocols are used by French neonatologists for the treatment of suspected maternofetal infection (SMFI). Three groups of premature and term neonates were included to study the impact of antibiotics on fecal flora: 10 infants with SMFI treated with amoxicillin and netilmicin (group BI), 10 infants with SMFI treated with amoxicillin, cefotoxime and netilmicin (group TRI) and 10 infants without antibiotic therapy as controls (group C). Group BI samples were colonized with Klebsiella oxytoca and Escherichia coli resistant to amoxicillin and by Enterococcus faecium and coagulase-negative staphylococci. In group TRI biodiversity of the intestinal flora was low, with rapid growth of staphyloccoci and occurrence of Candida spp. These modifications of the intestinal flora should encourage us to use antibiotic treatment as targeted as possible.

This study represents a 1-year surveillance period using our epidemiology-based principles published and successfully followed since 1979: weekly culture for yeasts of oral and anal swabs, treatment with oral nystatin of all colonized newborns, and good hygiene/handwashing. Colonization was demonstrated in 23 out of 791 newborns admitted from October 1998 to September 1999. Twenty-two strains of Candida were identified: 16 C. albicans, 2 C. parapsilosis, 3 C. glabrata, and 1 C. tropicalis. Symptoms were erythema of the buttocks in 6 colonized newborns. No other culture positive for Candida could be found. Previous contamination was the main source (previous stay in an intensive care unit, rarely maternal origin). Contamination in the unit was unlikely. Eradication of Candida could be observed within 1 week. These good results, controversial in the literature, were obtained following epidemiological conclusions and support our guidelines.

Previous studies have shown a reduction of dopaminergic D2 receptors (D2R) in the striatum after hypoxia-ischemia in newborn rats. We show here an early and transient reduction of mRNA D2R in nonatrophic brains following hypoxia-ischemia. The left carotid artery of P7 rats was ligated followed by hypoxia for 2 h. The rats were sacrificed after 24 h, 48 h and 14 days. D2R mRNA was studied by in situ hybridization, the cell number by conventional histology, and neuronal and astrocyte differentiation by immunohistochemistry. A 20% reduction of striatal mRNA D2R occurred 24 h after hypoxia-ischemia, whereas no reduction was observed after 48 h and 14 days. There were no differences in total cell number and in the expression of neuronal (MAP-1, MAP-2) and astrocyte (GFAP) markers between both brain hemispheres nor between control and hypoxia-ischemia animals. The early decrease in mRNA D2R could explain the delayed reduced D2R after neonatal hypoxia-ischemia.

Resume Objectifs Cette etude prospective cas-temoins a eu pour but de determiner si et en quoi le developpement medical, psychologique et affectif est different chez les grands prematures et les nouveau-nes a terme, tout handicap severe exclu. Population et methode Les enfants d'âge gestationnel inferieur ou egal a 33 semaines d'amenorrhee (SA) ont ete inclus de decembre 1992 a janvier 1994 et apparies chacun a deux temoins nes a terme. L'evaluation des enfants a ete realisee par les memes examinateurs, a l'âge corrige de neuf a dix mois. Resultats Cinquante prematures d'âge gestationnel moyen de 30,7 SA et 100 temoins ont ete compares. Les principales maladies des enfants ont ete: affections bronchopulmonaires ( p = 0,03) et troubles du sommeil ( p = 0,027). Un handicap moteur a ete suspecte chez 9 % des cas et chez aucun temoin ( p = 0,000 03, odds-ratio = 3,44). Les facteurs differenciant, par l'analyse multivariee, les cas des temoins etaient la perturbation de la relation mere-enfant (odds-ratio = 39,5), l'anxiete maternelle (odds-ratio = 13,3), la pauvrete des mimiques (odds-ratio = 5,6), les anomalies du tonus peripherique (odds-ratio = 39,5) et les troubles du sommeil (odds-ratio = 5,8). Conclusion Les prematures avaient un risque accru de perturbation de la relation mere-enfant mais pas du developpement psychoaffectif.

The main contribution of EEG during intensive care in infants with hypoxic-ischemic encephalopathy is i) to help determine whether infants with subtle clinical manifestations present with epileptic seizures, ii) to determine whether paralyzed or heavily sedated infants present with convulsive phenomena, iii) to assess the therapeutical response to anticonvulsants, 4) to contribute, in combination with ultrasound scanning, to diagnostic evaluation of the severity of lesions, and to provide valuable prognostic informations via the analysis of the background activity, as normal EEG is highly predictive of normal outcome, whereas various abnormal EEG features are constantly associated with subsequent major neurological abnormalities or death. These EEG features are readily available from a very early stage and may both precede and be prognostically more sensitive than information obtained from ultrasound. Recording of neonatal electroencephalogram requires awareness of the normal development of electroencephalographic features in the newborn, skilled technicians, and experienced readers of EEG tracings.

La radiosensibilite des progeniteurs hematopoietiques murins CFU-C a ete determinee in-vivo apres irradiation en champ mixte y-neutron. Cinq rapports τ (D/D total ) ont ete testes. La radiosensibilite augmente avec la baisse de τ, indice de l'elevation du taux de neutrons dans le rayonnement. Les D 0 mesurees ont varie de 3,3 ± 0,22 a 0,85 ± 0,04 Gy pour les τ extremes. L'Efficacite Biologique Relative (EBR) des differents rayonnements etudies varie de 1,2 ± 0,08 a 4,7 ± 0,24. La relation entre l'EBR et τ ne semble pas lineaire. Une etude de la conjugaison des effets des composantes du rayonnement suggere une infra-additivite de l'action letale des rayonnements γ et neutronique delivres simultanement. Ces resultats indiquent que la variation de qualite du champ mixte au niveau des territoires hematopoietiques a une grande importance en terme de letalite, de dommages et egalement en terme de capacite de restauration.

When an irradiation accident occurs, it is very important for medical treatment to be able to reconstruct the cartography of the dose absorbed by the irradiated person. A cotton textile coated with an α-alumina dosimetric powder is suitable to clothe persons subjected to irradiation risks. With some precautions, the dose may be measured by thermoluminescence (TL). Responses of the aluminised cotton textile relative to the absorbed dose are shown for different ratios of DjD n and relative to the photon energy.

We report three cases of transient myocardial hypertrophy, diagnosed by echocardiography, occurring between the second and seventh days of life in neonates with initially normal ventricular myocardial wall thickness. The three term neonates had perinatal injury with acute fetal distress. In all three cases electrocardiographic and biologic signs of myocardial ischemia were present. The first echocardiographic results showed abnormalities in systolic or diastolic left ventricular function, without hypertrophy of the walls. The hypertrophic cardiomyopathy (HCM) occurred between days 2 and 7 and affected first the interventricular septum and the free wall of the right ventricle. The left ventricular posterior wall subsequently became abnormal, resulting in severe overall myocardial hypertrophy, which finally disappeared in all three cases between 1 and 5 months of life. Such observations of early severe and transient HCM have not been previously reported. We believe it is a consequence of myocardial ischemia due to acute fetal distress. The prognosis of this type of HCM is good, in contrast to that of other primitive HCM occurring in neonates.

When an irradiation accident occurs, it is very important for medical treatment to be able to reconstruct the cartography of the dose absorbed by the irradiated person. The cotton textile 'dosimetric cotton' to which an α-alumina dosimetric powder is fixed, has been devised in LPES-CRESA. It can be used to clothe persons subjected to irradiation risks. By taking a number of precautions, the dose may be determined from measurements of the thermoluminescence (TL). Some TL tests, which are meant to describe the characteristics of the dosimetric textile in various irradiation configurations, are described. In particular, it is shown that the dosimetric cotton is especially appropriate for gamma dosimetry in mixed neutron-gamma fields. It covers the field of accident dosimetry extensively and the low detection limit actually obtained is 0.10 Gy.

Because diphtheria, tetanus, pertussis and poliomyelitis vaccine is routinely given during the period of highest incidence of sudden infant death syndrome (SIDS), we carried out a retrospective case-control study to assess whether such vaccination increased the risk of SIDS. The vaccination status of 118 SIDS and 332 control children, matched for sex, date of birth and age of the victims at death, was compared: the victims of SIDS were not significantly more often vaccinated than control children, the odds ratio was estimated at 1.9 with a 95% confidence interval from 0.9 to 3.9. There was a statistical difference between vaccination status of SIDS cases and controls aged less than three months. Nine percent of SIDS cases under 3 months had been vaccinated whereas the matched controls had not. In our study DTCP vaccination was not a risk factor for SIDS; although more of the SIDS infants less than 3 months of age had been vaccinated. This result however, concerns only one subgroup of the population studied and needs to be confirmed with another study of only SIDS infants less than 3 months of age, because DTCP vaccination was not a risk factor for SIDS when considering the total sample of the study.

Using a PC computer with custom-written code (based on the Monte-Carlo method) we computed the number and characteristics of latent proton tracks produced between the surface and a depth of 20μm in a CR39 solid state nuclear track detector, which itself was used as a radiator (n,p conversion). The incident neutron flux direction was normal to the surface of the CR39 sheet, and was monoenergetic (1 MeV). A numerical simulation of chemical etching was then used for the obtained latent proton tracks. The method includes the notion of critical angle for the etching phase, and makes it possible to determine the true number of etched tracks created, as well as the geometrical parameters of these tracks, such as depth and their major and minor axes.

wells is enabled by “printing” into the simulation grid an appropriate 3D pattern of connected facies extracted from the 3D training image, after a full scan of the training image has been performed. Multiple-point simulation can be run using either stationary or non-stationary training images.

An interdisciplinary study was conducted to evaluate the relationship between geological and paleontological parameters and the bacterial and archaeal community structure of two contrasted subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lions). Since both depositional environments were well-documented in this area, large data-sets were available and allowed to calibrate the investigated cores with several reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. Molecular-based fingerprints showed that the Ligurian Sea sediments, characterized by an heterolithic facies with numerous turbidites from a deep-sea levee, were unexpectedly dominated by Betaproteobacteria (more than 70 %), at the base of the core mainly below five meters in the sediment. Analysis of relative betaproteobacterial abundances and turbidites frequency indicated that the microbial diversity was controlled by the important climatic changes occurring during the last 20 ka. This result was supported by statistical direct multivariate canonical correspondence analyses (CCA). In contrast, the Gulf of Lions core, characterized by a homogeneous lithology of upper-slope environment, was dominated by the Bacteroidetes group and in a lesser extent, by the Betaproteobacteria group. At both sites, the dominance of Betaproteobacteria coincided with increased terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lions, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western-Mediterranean Sea sediments has left its imprint on the structure/composition of the microbial communities during the late Quaternary.

The acute effects of surfactant instillation rate on the cerebral and cardiovascular haemodynamics were studied in a randomised trial of 27 preterm neonates with respiratory distress syndrome (RDS). Cerebral blood flow velocity (CBFV), mean arterial blood pressure (MABP), blood gases and electroencephalogram (EEG) were continuously recorded before, during, and for at least 10 minutes after the administration of surfactant. The measurements were repeated one, three, and six hours later. Left ventricular output (LVO) and ductal patency were assessed 10 minutes before and then one, three, and six hours after surfactant administration. Surfactant (Exosurf) was instilled rapidly over five minutes in 13 infants and slowly over 15 minutes in 14 infants. The rapid group showed a significant but transient increase (mean 38%) in CBFV, a rise strongly related to an increase in carbon dioxide tension. No significant change in CBFV was observed in the slow group. There were no significant changes in EEG, MABP, LVO, or ductal shunting in either group. The findings suggest that rapid instillation of Exosurf leads to an increase in CBFV and partial carbon dioxide pressure (PCO2) and requires a close monitoring of blood gases to maintain adequate ventilation. Furthermore, the findings should alert clinicians to the need for slow infusion of Exosurf.

Cd1−xZnxTe layers covering the composition range of 0

Le travail presente dans cet article rentre dans le cadre de la cartographie de dose et de la dosimetrie neutronique utilisant une conversion (n, p), ceci a des fins de radioprotection. Il s'integre dans une etude visant a la mise au point d'un logiciel permettant, entre autres, a partir de l'observation des parametres morphologiques d'une trace developpee de proton de recul, de determiner son energie et son incidence. Ce logiciel permettra d'autre part d'evaluer les parametres des interactions particule-matiere qui ne donnent pas lieu a des traces observables. Dans cette etude, il a ete mis en œuvre une analyse mathematique du developpement des traces latentes permettant de determiner experimentalement la vitesse VT d'attaque le long de celles-ci a partir de la mesure du parcours des protons. Cette derniere partie fait l'objet de cet article. Celui-ci se limite a la description d'une methode de determination du parcours des protons de recul dans un polymere (le CR 39) utilise comme detecteur solide de traces nucleaires (DSTN). Ces mesures de parcours basees sur une methode d'analyse mathematique seront comparees a celles deduites du transfert lineique d'energie (TLE) calculees avec le logiciel TRIM 91. La methode d'analyse sera verifiee par des mesures microprofilometriques.

Ce papier porte sur les etudes menees pour qualifier le SOS Chromotest, un test de genotoxicite mis au point par l'Institut Pasteur (Paris), en tant que «dosimetre d'effets» pour les rayonnements ionisants. La «dosimetrie d'effets» est definie comme toute methode de mesure capable de caracteriser et de denombrer directement ou indirectement les lesions physico-chimiques primitives produites par les rayonnements sur les micromolecules du milieu vivant, principalement l'ADN, puisque la majorite des effets biologiques en decoule

The efficacy of sumatriptan, a 5-HT1 receptor agonist, in patients with migraine attacks occurring despite prophylactic treatment with oral dihydroergotamine, was assessed in a double-blind placebo-controlled study involving 76 patients. Thirty-seven patients were treated with a subcutaneous injection of 6 mg sumatriptan self-administered with an auto-injector and 39 with placebo given by the same route. Patients having inadequate relief were allowed to use a second injection of test medication 1 hour later and rescue treatment between 2 hours and 24 hours after the first dose. Headache relief was achieved within 2 hours after sumatriptan in 26 patients (70%) compared to 8 patients (21%) in the placebo group (P < 0.0001). Of these patients, 19 (51%) and 3 (8%) were, respectively, pain free at this time. A second injection of sumatriptan was used by 8 (22%) patients compared to 30 (77%) patients in the placebo group (P < 0.0001), whereas rescue medication was used respectively by 13 (35%) and 22 (58%) patients (P < 0.024). The adverse event profile of sumatriptan was not affected by the concomitant use of dihydroergotamine and side-effects were all minor and transient. Patient satisfaction was significantly higher in the sumatriptan group (75%) compared to patient satisfaction with placebo (16%). These results show that the high efficacy rate of subcutaneous sumatriptan and its safety profile remain unchanged in migraine patients receiving oral dihydroergotamine as prophylaxis.

Transcranial Doppler ultrasound (TCD) provides the neonatolo- gist and the pediatric intensivist with the opportunity to monitor hemodynamics noninvasively. Continuous recording of the Doppler waveforms and intracranial pressure can make it possible to determine the critical cerebral perfusion pressure and to improve the control of the therapy of cerebral edema. This article reviews the potential of TCD as a monitoring instrument in pediatric intensive care.

Many of the drugs used in neonatal intensive care units might impede cerebral blood flow, thereby increasing the risk of intraventricular hemorrhage and periventricular leukomalacia. Our studies focussed on sick preterm neonates who were treated with the following drugs: caffeine (20 mg/kg i.v., as caffeine citrate); phenobarbital (loading dose: 20 mg/kg); indomethacin (0.2 mg/kg/dose, every 12 h three doses), and synthetic surfactant (Exosurf; 50 mg/kg = 5 ml/kg intratracheally). All of the drugs studied, except indomethacin, had no adverse effect on cerebral hemodynamics.

Intraoperative Doppler sonographic examinations were carried out on seven preterm neonates to measure cerebral blood flow velocity changes in the anterior cerebral arteries during ductus arteriosus ligation. Age at surgery was 12 +/- 6 days. Continuous recordings during the operative procedure showed a rapid increase in diastolic blood pressure (P less than 0.01), whereas systolic blood pressure was not significantly higher compared with pre-occlusion values. In the anterior cerebral arteries, ductal closure led to a decrease in resistance index of Pourcelot (mean = 1.02 +/- 0.08 vs 0.65 +/- 0.07 (P less than 0.001)) and to an increase in area under the velocity curve (mean = 3.64 +/- 0.38 vs 8.16 +/- 1.07 (P less than 0.001)). These changes were associated with a corresponding increase of the end diastolic flow velocity (P less than 0.001) but no change in the peak systolic velocity. The heart rate did not change significantly during ductal closure. TcPO2, TcPCO2 remained normal during the study period. These data indicate that changes in cerebral blood flow velocity during surgical ligation are principally determined by changes in systemic diastolic pressure. Systolic blood pressure and peak systolic flow velocity remain unchanged or slightly higher than preligation values, thereby restoring normal cerebral blood flow velocity pattern without increasing the stress on the wall of cerebral vessels and thus the risk of peri-intraventricular haemorrhage.

Serial ultrasound imaging of the brain was carried out in 87 preterm infants of 27 to 36 weeks' gestational age while they were in the special care nursery and during their first postnatal year. None had evidence of intracranial disease during the neonatal period and 94% had good neurodevelopmental outcome at 2 years of age. Lateral ventricle area measurements were plotted against independent variables including postnatal age and head circumference at the time of the examination. The measurements increased as age and head circumference increased. During the first six weeks of life the mean (SD) postnatal head circumference growth velocity (rate of growth) was 0.53 (0.13) cm/week and the mean postnatal ventricular area growth velocity was 0.39 (0.19) mm2/week. A reference range for lateral ventricle area values was developed from these serial measurements in infants with documented good short term developmental outcome.

The effect of therapeutic doses of indomethacin versus a placebo on cerebral hemodynamics was studied in nine preterm infants using Doppler ultrasound. Three doses of indomethacin (0.2 mg/kg) induced a significant decrease in the mean frequency compared to the placebo. Heart rate, blood pressure, transcutaneous carbon dioxide tension, and transcutaneous oxygen tension remained stable throughout the study. The changes in mean frequency occurred rapidly and were sustained at significantly diminished levels for at least 1 hour. All infants were mechanically ventilated, and the increase of mean frequency secondary to suctioning was significantly attenuated after each dose of indomethacin as compared to the placebo. The results confirmed that infusion of indomethacin caused a reduction in cerebral blood flow, probably by vasoconstriction of cerebral vessels. Indomethacin also seemed to attenuate the cerebrovascular response to hypercapnia induced by endotracheal suctioning. Even so, and because of the alteration of resting cerebral hemodynamics, we do not support the recommendation that indomethacin should be used prophylactically to prevent patent ductus arterious or periventricular intraventricular hemorrhage.

Fe/Ti metallic multilayers with an average Fe33Ti67 composition have been studied by X-ray diffraction, Mossbauer spectroscopy and electrical resistivity as a function of period. For small periods, broad diffraction peaks characteristic of a disordered, amorphous-like structure are observed, although composition modulation still exists along the growth direction. Beyond Lambda =4 nm, crystalline Ti appears with a BCC structure. It then reverts to its stable HCP form for Lambda =6 nm, with its c axis along the growth direction. At a period of 8 nm, the iron-rich layer in turn crystallises. This correlates to a sudden decrease of the electrical resistivity. The appearance of this Fe-rich BCC phase, corresponding to the onset of magnetic ordering in the Mossbauer spectra, induces a change in the texture of the titanium layer, the c axis now lying preferentially in the plane. Anomalies in both the lattice parameters and size of the crystallites occur from this period up to about 12 nm, whereas a plateau is observed for the electrical resistivity. For larger periods, the Ti content of the Fe-rich BCC phase decreases, corresponding to the further decrease of the electrical resistivity and increase of both hyperfine field and magnetic contribution in the Mossbauer spectra.