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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/S0967-0637(99)00101-6 Byline: M Goutx, A Momzikoff, L Striby, V Andersen, J.C Marty, I Vescovali Keywords: Particle fluxes; High-frequency sampling; Particulate organic carbon; Proteins; Lipid classes; Northwestern Mediterranean Abstract: Sinking particles were collected every 4h with drifting sediment traps deployed at 200m depth in May 1995 in a 1-D vertical system during the DYNAPROC observations in the northwestern Mediterranean sea. POC, proteins, glucosamine and lipid classes were used as indicators of the intensity and quality of the particle flux. The roles of day/night cycle and wind on the particle flux were examined. The transient regime of production from late spring bloom to pre-oligotrophy determined the flux intensity and quality. POC fluxes decreased from, on average, 34 to 11 mg m.sup.-2 d.sup.-1, representing 6-14% of the primary production under late spring bloom conditions to 1-2% under pre-oligotrophic conditions. Total protein and chloroplast lipid fluxes correlated with POC and reflected the input of algal biomass into the traps. As the season proceeded, changes in the biochemical composition of the exported material were observed. The C/N ratio rose from 7.8 to 12. Increases of serine (10-28% of total proteins), total lipids (7-9 to 14-28% of POC) and reserve lipids (1-5 to 5-22% of total lipids) were noticeable, whereas total protein content in POC decreased (20-27 to 18-7%). N-acetyl glucosamine, a tracer of fecal pellet flux, showed that zooplankton grazing was a major vector of downward export during the decaying bloom. Against this background pattern, episodic events specifically increased the flux, modifying the quality and the settling velocity of particles. Day/night signals in biotracers (POC, N-acetyl glucosamine, protein and chloroplast lipids) showed that zooplankton migrations were responsible for sedimentation of fresh material through fast sinking particles (V=170-180md.sup.-1) at night. Periodic signatures of re-processed material (high lipolysis and bacterial biomass indices) suggested that other zooplankton fecal pellets or small aggregates, probably of lower settling velocities (V Article History: Received 6 October 1997; Revised 3 March 1999; Accepted 25 June 1999

Researchers at the DYFAMED permanent station in the northwestern Mediterranean Sea determined monthly vertical profiles of iodide, iodate and total free iodine in the area for a period of one year. Differential pulse polarography and cathodic stripping square wave voltammetry were used to determine dissolved iodate and iodide, respectively. The predominant species present was iodate while iodide was concentrated in surface waters. Total free iodine was slightly lower in surface waters than in deep waters.

Abstract: We present results of several years of research and data processing aimed at modelling the Mars gravity field and its longest wavelength time variations. The new solution includes tracking data from Mars Global Surveyor (MGS) from 1998 to 2006 (end of mission) and from Mars Odyssey from 2002 to the spring of 2008; this is the longest analyzed data set from these two orbiter missions as compared to previous works. The new model has been obtained by a team working in Europe, independently from the works of groups at NASA Jet Propulsion Laboratory (JPL) and Goddard Space Flight Center (GSFC), also with totally independent software. Observations consist in two and three-way Doppler measurements (also one way for MGS), and range tracking data collected by the Deep Space Network and have been processed in 4 day arcs, taking into account all disturbing forces of gravitational and non-gravitational origins; for each arc the state vector, drag and solar pressure model multiplying factors, and angular momentum dump parameters are adjusted. The static field (MGGM08A) is represented in spherical harmonics up to degree and order 95 and is very close to previously published models (in terms of spectral components and also over specific features); correlations with the global Mars topography are established and apparent depths of compensation by degree are derived. Lumped zonal harmonics of degree two and three are solved for every 10 days, exhibiting variations in line with previous results (including authors’ ones); the work also shows the difficulty of finding clean signatures (annual and semi-annual) for the zonal coefficient of second degree. The k 2 Love number is also derived from the ensemble of data, as well as from subsets of them; values between 0.110 and 0.130 are found, which are consistent with the existence of a Martian fluid core of significant radius. [Copyright &y& Elsevier]

Abstract: Circulation on blood extracorporeally through plastic tubing activates several pathways including systemic inflammation and oxidative stress. These phenomena are suspected to participate to neurological and cardiovascular side effects observed in the patients under cardiopulmonary bypass (CPB). A direct relationship, in diabetic patients, between hyperglycemia and morbidity and mortality has been established. However, it is still unclear whether perioperative hyperglycemia has a direct effect on adverse events in cardiac surgery. The purpose of this study was to determine the influence of hyperglycemia on inflammation and oxidative stress in patients under CPB during cardiac surgery. Material and methods: Control patients (n =17) and diabetic (type 2) patients (n =13) were included in this study. Blood samples were drawn before, during and after the CPB. Oxidative stress was evaluated in the plasma by direct and indirect approaches. Direct detection of ascorbyl radicals was assessed by electron spin resonance spectroscopy. An index: ascorbyl radical/vitamin C ratio is an indicator of the degree of oxidative stress taking place in the plasma. Oxygen radical absorbing capacity (ORAC) values were used as measurement of antioxidant capacity of the plasma. To determine inflammation profile of patients, we measure the evolution of plasma concentration of interleukin 8 (IL-8). Results: During cross clamping and post-CPB, the index ascorbyl radical/vitamin C is increased; the value of the index is more significant in diabetic patients. Concomitantly, ORAC values decreased in all the patients during cross clamping (p <0.05). Results concerning inflammatory index showed that IL-8 levels increased during the CPB. Conclusion: In conclusion, the current study indicates that a systemic oxidative stress occurs during CPB and post-CPB periods and that in patients with type 2 diabetes mellitus, the systemic oxidative stress was increased. [Copyright &y& Elsevier]

The scientific objectives of a geodetic experiment based on a network of landers, such as NEIGE (NEtlander Ionosphere and Geodesy Experiment) are to improve the current knowledge of Mars'' interior and atmosphere dynamics. Such a network science experiment allows monitoring the motions of the Martian rotation axis with a precision of a few centimeters (or milli-arc-seconds (mas)) over annual and sub-annual periods. Thereto, besides radio tracking of a Mars orbiter from the Earth, radio Doppler shifts between this orbiter and several landers at the planet''s surface will be performed. From the analysis of these radio Doppler data, it is possible to reconstruct the orbiter motion and Mars'' orientation in space. The errors on the orbit determination (position and velocity of the orbiter) have an impact on the geodetic parameters determination from the Doppler shifts and must be removed from the signal in order to achieve a high enough accuracy. In this paper, we perform numerical simulations of the two Doppler signals involved in such an experiment to estimate the impact of the spacecraft angular momentum desaturations on the determination of Mars'' orientation variations. The attitude control of the orbiter needs such desaturation maneuvers regularly repeated. They produce velocity variations that must be taken into account when determining the orbit. For our simulations, we use a priori models of the Martian rotation and introduce the spacecraft velocity variations induced by each desaturation event. By a least-squares adjustment of the simulated Doppler signals, we then estimate the orbiter velocity variations and the parameters of the Mars'' rotation model. We show that these velocity variations are ill resolved when the spacecraft is not tracked, therefore requiring a near-continuous tracking from the Earth to accurately determine the orbit. In such conditions we show that only 15– of lander–orbiter tracking per week allows recovering Mars'' orientation parameters with a precision of a few mas over a period of 1 Martian year. [Copyright &y& Elsevier]

Abstract: In the frame of a comparison between Earth, Venus, and Mars, a vision on future geodesy missions to Mars is discussed with particular focus on furthering our understanding of the interior, rotation, and orientation of this terrestrial planet. We explain how radioscience instruments can be used to observe the rotation and orientation and therewith to study the deep interior of Mars and its global atmosphere dynamics. Transponders in X-band and Ka-band are proposed with radio links between a lander or a rover and an orbiter around Mars and/or directly to the Earth. The radio budget links are studied in the frame of possible mission constraints and simulations are performed, which show that important information on the interior of Mars can be obtained from the radioscience data. From the observation of Mars’ orientation in space and of tidal effects on a spacecraft orbiting around Mars we show that it is possible for instance to constrain the dimension and composition of the core, the percentage of light element within the core, and to determine the presence of a pressure-induced mineral-phase transition at the bottom of the mantle. [Copyright &y& Elsevier]

Abstract: The kinetic parameters, namely the triplet activation energy E A, model function f(α) or g(α) and pre-exponential factor A of the oxidation of Constantan tapes in 1atm of oxygen have been determined from both isothermal and non-isothermal thermogravimetry. For isothermal experiments, with temperatures ranging from 650°C to 900°C, the results from direct conversion of the weight increase as a function of the time and curve fitting, are compared with the isoconversion method. For the non-isothermal experiments, with heating rates from 1°C/min to 20°C/min, comparison is made between the Friedman differential method and the integral methods of Kissinger, Ozawa and Li and Tang. All methods give apparent activation energies with relative standard deviations as low as 3%. The results converge to the identification of three stages in the oxidation behaviour. A parabolic law for reaction extents α below 15% with E A =246±7kJmol−1, ln A =14.3, is followed by two linear stages with E A =244±4kJmol−1 and ln A =15.3 for 0.18< α <0.35 and E A =228±15kJmol−1, ln A ≈13 for α >45%, respectively. [Copyright &y& Elsevier]

Abstract: The determination of the ephemeris of the Martian moons has benefited from observations of their plane-of-sky positions derived from images taken by cameras onboard spacecraft orbiting Mars. Images obtained by the Super Resolution Camera (SRC) onboard Mars Express (MEX) have been used to derive moon positions relative to Mars on the basis of a fit of a complete dynamical model of their motion around Mars. Since, these positions are computed from the relative position of the spacecraft when the images are taken, those positions need to be known as accurately as possible. An accurate MEX orbit is obtained by fitting two years of tracking data of the Mars Express Radio Science (MaRS) experiment onboard MEX. The average accuracy of the orbits has been estimated to be around 20–25m. From these orbits, we have re-derived the positions of Phobos and Deimos at the epoch of the SRC observations and compared them with the positions derived by using the MEX orbits provided by the ESOC navigation team. After fit of the orbital model of Phobos and Deimos, the gain in precision in the Phobos position is roughly 30m, corresponding to the estimated gain of accuracy of the MEX orbits. A new solution of the GM of the Martian moons has also been obtained from the accurate MEX orbits, which is consistent with previous solutions and, for Phobos, is more precise than the solution from the Mars Global Surveyor (MGS) and Mars Odyssey (ODY) tracking data. It will be further improved with data from MEX-Phobos closer encounters (at a distance less than 300km). This study also demonstrates the advantage of combining observations of the moon positions from a spacecraft and from the Earth to assess the real accuracy of the spacecraft orbit. In turn, the natural satellite ephemerides can be improved and participate to a better knowledge of the origin and evolution of the Martian moons. [Copyright &y& Elsevier]

The Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) mission has provided an opportunity to improve our knowledge of Mars' interior via the Rotation and Interior Structure Experiment (RISE). RISE provides information on the rotation of Mars by measuring the Doppler shift of radio transmissions from InSight to NASA's Deep Space Network (DSN) on Earth. Through the combination of one year of Doppler data from InSight with previous data from the Viking-1 lander, Mars Pathfinder, and Opportunity missions, data spanning 43 years from 1976 to 2019 are used to estimate the Mars precession rate as −7605 ​± ​3 milliarcseconds per year. This result is consistent with the precession rate estimated from Doppler tracking of previous landers and orbiters alone. • The Doppler shift of signals between Mars landers and Earth tracking stations can be used to estimate Mars' rotation. • One year of InSight tracking data are combined with data from Opportunity, Pathfinder, and Viking-1 to estimate Mars' precession rate. • Mars' precession rate is used to compute the mean Moment of Inertia, which constrains the radius of the core. [ABSTRACT FROM AUTHOR]