Off Shelf Fluxes of Labile Materials by an Upwelling Filament in the NW Iberian Upwelling System

in Progress in Oceanography (2001), 50(2-4), 321-337

Daily changes in the concentrations of carbon and nitrogen species were monitored during the course of a Lagrangian drifter experiment in a recurrent upwelling filament south of Cape Finisterre (NW ... [more ▼]

Daily changes in the concentrations of carbon and nitrogen species were monitored during the course of a Lagrangian drifter experiment in a recurrent upwelling filament south of Cape Finisterre (NW Iberian Upwelling System). A drifting buoy released at the southern edge of the upwelling centre generated by the Cape moved 60km southwestwards from 3 to 7 August 1998. Organic matter in the 50m deep study water mass (average 77±2 μM C) consisted of: 57μM C of dissolved organic matter (DOM) with a C/N molar ratio of 19±2; 6μM C of DOM with a C/N ratio of 9±2, and 14μM C of 50% DOM and 50% suspended organic matter (POMsusp) with a C/N ratio of 6.0±0.4. Net conversion of consumed inorganic salts into accumulated TOM=POMsusp+DOM was 40% for nitrogen and 30% for carbon. Since the parcel of water crossed the shelf-edge, these conversion efficiencies are equivalent to net horizontal export-ratio of 0.4 and 0.3 respectively. A second drifter was deployed in the offshore-end of the filament, and was displaced 20km west between 14 and 17 August 1998. Nitrate was exhausted in the surface water and no significant changes were observed in the variables measured during the course of the second experiment. Low C/N ratios (6.5±0.4) and rapid POMsusp/DOM inter-conversion in the 20 μM C excess observed in the study volume points to the persistence of the labile materials formed on the shelf during transport to the ocean. Our data demonstrate a) the key role of upwelling filaments in off-shelf export of organic materials and b) the major contribution of DOM to this horizontal export, a previously unaccounted amount. [less ▲]

Off-line processing of memory traces during human sleep: Contribution of functional neuroimaging

in Sleep & Biological Rhythms (2003), 1

Sleep is thought to participate in the consolidation of recent memory traces. We tested this hypothesis in humans by using functional neuroimaging (functional magnetic resonance imaging and positron ... [more ▼]

Sleep is thought to participate in the consolidation of recent memory traces. We tested this hypothesis in humans by using functional neuroimaging (functional magnetic resonance imaging and positron emission tomography). First, following the training procedural visuo-motor learning task (pursuit task), total sleep deprivation on the first post-training night significantly deteriorates the gain in performance, which is usually observed after one complete night of sleep. In parallel, sleep deprivation hampers the changes in functional segregation and connectivity, which underpin the gain in performance usually observed in subjects allowed to sleep on the first post-training night. Second, following the training on an implicit memory task (probabilistic serial reaction time task), some brain areas are reactivated during rapid eye movement (REM) sleep on the first post-training night. The reactivation was shown to be related to the processing of high-level material and to be modulated by the amount of learning achieved during the training session. These changes in activity do not involve isolated brain areas but entire macroscopic cortico-subcortical networks. Taken together, the results suggest an off-line processing of recent memory traces during sleep. [less ▲]

L'office de la Trinité. Liège, Metz, Mayence, Saint-Gall

Conference (2008, November 20)

L’histoire de l'office de la Trinité a déjà fait couler beaucoup d’encre. Les philologues se sont intéressés à la place du formulaire dans l’histoire des offices versifiés du haut moyen âge, aux sources ... [more ▼]

L’histoire de l'office de la Trinité a déjà fait couler beaucoup d’encre. Les philologues se sont intéressés à la place du formulaire dans l’histoire des offices versifiés du haut moyen âge, aux sources d’inspiration des textes, au principe et à la stratégie d’inspiration ; les musicologues au mode de composition musicale comme au rapport entre les textes chantés et la musique. Par contre, peu a été dit sur la transmission du formulaire – texte et musique confondus – dans l’Eglise occidentale . Cette communication entendait proposer un hypothétique schéma de propagation du formulaire dans la partie orientale de l’ancien empire carolingien, inséré dans une plus large réflexion en cours sur les motifs extra-liturgiques du succès de la première fête votive de l’histoire de la liturgie dans l’Eglise catholique d’Occident. [less ▲]

Offline persistence of memory-related cerebral activity during active wakefulness

in PLoS Biology (2006), 4(4), 100

Much remains to be discovered about the fate of recent memories in the human brain. Several studies have reported the reactivation of learning-related cerebral activity during post-training sleep ... [more ▼]

Much remains to be discovered about the fate of recent memories in the human brain. Several studies have reported the reactivation of learning-related cerebral activity during post-training sleep, suggesting that sleep plays a role in the offline processing and consolidation of memory. However, little is known about how new information is maintained and processed during post-training wakefulness before sleep, while the brain is actively engaged in other cognitive activities. We show, using functional magnetic resonance imaging, that brain activity elicited during a new learning episode modulates brain responses to an unrelated cognitive task, during the waking period following the end of training. This post-training activity evolves in learning-related cerebral structures, in which functional connections with other brain regions are gradually established or reinforced. It also correlates with behavioral performance. These processes follow a different time course for hippocampus-dependent and hippocampus-independent memories. Our experimental approach allowed the characterization of the offline evolution of the cerebral correlates of recent memories, without the confounding effect of concurrent practice of the learned material. Results indicate that the human brain has already extensively processed recent memories during the first hours of post-training wakefulness, even when simultaneously coping with unrelated cognitive demands. [less ▲]

Les offrandes liées à la fécondité et à la maternité dans la Gaule romaine

in Revue du Praticien (La) (2006), 56(7), 804-9

Offre foncière et demande pour les activités économiques en 2015

Conference (2002, November 14)

OGLE-2008-BLG-510: first automated real-time detection of a weak microlensing anomaly - brown dwarf or stellar binary?

in Monthly Notices of the Royal Astronomical Society (2012), 424

The microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system ... [more ▼]

The microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrate that: (1) automated real-time detection of weak microlensing anomalies with immediate feedback is feasible, efficient and sensitive, (2) rather common weak features intrinsically come with ambiguities that are not easily resolved from photometric light curves, (3) a modelling approach that finds all features of parameter space rather than just the 'favourite model' is required and (4) the data quality is most crucial, where systematics can be confused with real features, in particular small higher order effects such as orbital motion signatures. It moreover becomes apparent that events with weak signatures are a silver mine for statistical studies, although not easy to exploit. Clues about the apparent paucity of both brown-dwarf companions and binary-source microlensing events might hide here. Based in part on data collected by MiNDSTEp with the Danish 1.54m telescope at the ESO La Silla Observatory. [less ▲]

OGLE-TR-211 - a new transiting inflated hot Jupiter from the OGLE survey and ESO LP666 spectroscopic follow-up program

in Astronomy and Astrophysics (2008), 482

We present results of the photometric campaign for planetary and low-luminosity object transits conducted by the OGLE survey in the 2005 season (Campaign #5). About twenty of the most promising candidates ... [more ▼]

We present results of the photometric campaign for planetary and low-luminosity object transits conducted by the OGLE survey in the 2005 season (Campaign #5). About twenty of the most promising candidates discovered in these data were subsequently verified spectroscopically with the VLT/FLAMES spectrograph. One of the candidates, OGLE-TR-211, reveals clear changes of radial velocity with a small amplitude of 82 m/s, varying in phase with photometric transit ephemeris. Further analysis confirms the planetary nature of this system. Follow-up precise photometry of OGLE-TR-211 with VLT/FORS, together with radial velocity spectroscopy, supplemented with high-resolution, high S/N VLT/UVES spectra allowed us to derive parameters of the planet and host star. OGLE-TR-211b is a hot Jupiter orbiting an F7-8 spectral type dwarf star with a period of 3.68 days. The mass of the planet is equal to 1.03±0.20 M_Jup, while its radius 1.36[SUP]+0.18[/SUP][SUB]-0.09[/SUB] R_Jup. The radius is about 20% larger than the typical radius of hot Jupiters of similar mass. OGLE-TR-211b is, then, another example of inflated hot Jupiters - a small group of seven exoplanets with large radii and unusually low densities - objects that are a challenge to the current models of exoplanets. Based on observations made with the FORS1 camera and the FLAMES/UVES spectrograph at the VLT, ESO, Chile (program 07.C-0706, 076.C-0122, and 177.C-0666) and 1.3-m Warsaw Telescope at Las Campanas Observatory, Chile. [less ▲]

OGO-4 observations of the ultraviolet auroral spectrum

in Planetary and Space Science (1976), 24

Auroral ultraviolet spectra in the range from 1200 to 3200 A have been obtained by the spectrometer on board the OGO-4 satellite. Emissions of N2, H, O, and N are readily identified. Atomic and molecular ... [more ▼]

Auroral ultraviolet spectra in the range from 1200 to 3200 A have been obtained by the spectrometer on board the OGO-4 satellite. Emissions of N2, H, O, and N are readily identified. Atomic and molecular intensities are deduced from the comparison with a synthetic spectrum and compare reasonably well with some previous measurements and calculations. A feature at 2150 A is assigned to the (1-0) NO gamma band. Taking into consideration the various excitation mechanisms of NO(A2 Sigma), it is proposed that energy transfer from N2 metastable molecules to oxygen accounts for the excitation of the NO gamma bands. In particular, it is suggested that the resonant reaction between O2 and highly metastable N2 molecules may be a major source of NO(A2 Sigma). [less ▲]

The OH Venus nightglow spectrum: intensity and vibrational composition from VIRTIS-Venus Express observations

in Planetary and Space Science (2012), 73(1),

Limb spectra of the OH nightglow emission corresponding to the ∆v=1 and ∆v=2 sequences have been collected with the VIRTIS infrared imaging spectrograph on board Venus Express between April 2006 and ... [more ▼]

Limb spectra of the OH nightglow emission corresponding to the ∆v=1 and ∆v=2 sequences have been collected with the VIRTIS infrared imaging spectrograph on board Venus Express between April 2006 and October 2008. A detailed statistical analysis shows that the peak intensity and altitude of the two vibrational sequences are significantly correlated, with a mean intensity ratio of the two sequences of 0.38±0.37. The altitude of the maximum of the ∆v=2 emission is located ~1 km lower than ∆v=1. A spectral analysis shows that the Δv=1 sequence is composed at 44.6% by the (1–0) band, 9.3% by the (3–2) band and 7.1% by the (4–3) band. The Δv=2 emission is best fitted if solely including the (2–0) band. A non-LTE model of OH vibrational population by the O3+H reaction including radiative and collisional relaxation has been used to compare the expected spectral distribution, the altitude of the emission peak and the emission rate under different assumptions on the quenching processes to those observed with VIRTIS. The adopted carbon dioxide, atomic oxygen and ozone densities are based on recent Venus Express remote sensing measurements. We find that the “sudden death” quenching scheme by CO2 produces inadequate spectral distribution between the various bands and insufficient airglow brightness. Instead, the observed spectral distribution and the total emission intensity are reasonably well reproduced with the single quantum jump model, a O density profile peaking at 103.5 km with a maximum value of 1.9×1011 cm−3, a O3 density profile peaking at 5.8×106 cm−3 at 96.5 km and a H density profile close to 108 cm−3 between 90 and 120 km, in agreement with several photochemical models. [less ▲]