Contribution to the study of composite spectra: XII. Spectroscopic orbits of eight southern stars

We present the results of a radial‐velocity study of eight southern SB1 spectroscopic binaries with composite spectra: HD 34318‐9, HD 47579‐80, HD 70442‐3, HD 74946‐7, HD 102171‐2, HD 120901‐2, HD 168701‐2, and HD 174191‐2. The observations were made at Haute‐Provence observatory with the CORAVEL instrument between 1982 and 2006. From the radial‐velocity measurements of the cool components, we derive the orbital elements of those spectroscopic binaries. Using all the available data, we obtain an estimation of the orbital inclination and the angular separation of the two components. Finally we discuss the rotation‐revolution synchronism of the cool components. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

7. Ancient Fossil Record and Early Evolution (ca. 3.8 to 0.5 Ga)

Once life appeared, it evolved and diversified. From primitive living entities, an evolutionary path of unknown duration, likely paralleled by the extinction of unsuccessful attempts, led to a last common ancestor that was endowed with the basic properties of all cells. From it, cellular organisms derived in a relative order, chronology and manner that are not yet completely settled. Early life evolution was accompanied by metabolic diversification, i.e. by the development of carbon and energy metabolic pathways that differed from the first, not yet clearly identified, metabolic strategies used. When did the different evolutionary transitions take place? The answer is difficult, since hot controversies have been raised in recent years concerning the reliability of the oldest life traces, regardless of their morphological, isotopic or organic nature, and there are also many competing hypotheses for the evolution of the eukaryotic cell. As a result, there is a need to delimit hypotheses from solid facts and to apply a critical analysis of contrasting data. Hopefully, methodological improvement and the increase of data, including fossil signatures and genomic information, will help reconstructing a better picture of life evolution in early times as well as to, perhaps, date some of the major evolutionary transitions. There are already some certitudes. Modern eukaryotes evolved after bacteria, since their mitochondria derived from ancient bacterial endosymbionts. Once prokaryotes and unicellular eukaryotes had colonized terrestrial ecosystems for millions of years, the first pluricellular animals appeared and radiated, thus inaugurating the Cambrian. The following sections constitute a collection of independent articles providing a general overview of these aspects.     

Speckle observations with PISCO in Merate – VII. Astrometric measurements of visual binaries in 2007

We present relative astrometric measurements of visual binaries made during the first semester of 2007, with the Pupil Interferometry Speckle camera and COronagraph (PISCO) at the 102-cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. We obtained 226 new measurements of 214 objects, with angular separations in the range 0.15–4.5 arcsec, and an average accuracy of 0.013 arcsec. The mean error on the position angles is     . Most of the position angles could be determined without the usual 180° ambiguity with the application of triple-correlation techniques and/or by inspection of the long integration files. We also present the new orbits we have computed for ADS 7871, 7982 and 8128, for which our measurements lead to large residuals and/or for which the revision is justified by the significant number of observations made since the publication of the previous orbit.     

Speckle observations with PISCO in Merate: IV. Astrometric measurements of visual binaries in 2005

We present relative astrometric measurements of visual binaries made during the second semester of 2005, with the speckle camera PISCO at the 102 cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. The purpose of this long term program is to improve the accuracy of the orbits and determine the masses of the components. We performed 130 new observations of 120 objects, with most of the angular separations in the range 0″.1–4″, and with an average accuracy of 0″.01. Most of the position angles could be determined without the usual 180. ambiguity with the application of triple‐correlation techniques, and their mean error is 0°8. We have found a possible new triple system: ADS 11077. The measurements of the closest binaries were made with a new data reduction procedure, based on model fitting of the background of the auto‐correlations. As this procedure proved to be very efficient, we have re‐processed the old observations of close binaries made with PISCO in Merate since 2004. We thus improved 20 measurements already published and obtained 7 new measurements for observations that were previously reported as “unresolved”. We finally present revised orbits for ADS 684, MCA 55Aac (in the Beta 1 Cyg–Albireo multiple system) and ADS 14783 for which the previously published orbits led to large residuals with our measurements and for which the new observations made since their computation allowed a significant improvement of those old orbits. The sum of the masses that we derived for those systems are consistent with the spectral type of the stars and the dynamic parallaxes are in good agreement with the parallaxes measured by Hipparcos. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Relative importance of dissolved and food pathways for lead contamination in shrimp

The relative importance of dissolved and food pathways and the influence of food type in the bioaccumulation and retention of lead in the shrimp Palaemonetes varians were examined using a radiotracer method. Shrimp were exposed to ²¹⁰Pb-labelled seawater or fed two types of ²¹⁰Pb-labelled food, viz. mussels or worms. The amount of radiotracer accumulated by shrimp was examined over a 7-day period, followed by a 1-month and a 7-day depuration period for the dissolved and food source, respectively. Steady state in the uptake was reached after 2 days exposure to dissolved lead, with a resultant estimated concentration factor of 98 ± 3. Transfer factors following ingestion of contaminated mussels and worms were lower than unity for both food types, with lead transfer from worms being significantly higher than that from mussels. Accumulation of dissolved Pb by shrimp was found to occur mainly through adsorption on the exoskeleton with a minor accumulation in the internal tissues probably resulting from the intake of seawater for osmoregulation. In contrast, lead taken up from contaminated food was readily absorbed and bound in the internal tissues of P. varians. Although the transfer of lead to P. varians through the ingestion of contaminated food was low (TF < 1%), it still represented 4 to 8% of the lead content in the prey which is a significant additional contribution of lead to the shrimp body burden. Independent of food type, following ingestion of contaminated food, approximately 23–27% of total lead accumulated in shrimp was located in the edible parts (e.g. muscle). Therefore, the food pathway is suggested to be a significant contributor to the lead transfer to humans through ingestion of contaminated shrimp. After exposure to contaminated food, lead loss kinetics were described by a two-component model, whereas Pb loss following direct uptake from seawater was best described by a three-component model. The additional compartment representing 64% of total Pb retained and characterized by a turnover < 10 min, corresponded to lead weakly adsorbed on the exoskeleton and incorporated in the hepatopancreas. Nevertheless, a significant fraction of lead accumulated from the dissolved (2%) and food (52–57%) pathways remained irreversibly retained in the tissues, suggesting that this organism could also serve as an effective long-term bioindicator of lead contamination in marine waters.     

Les surfaces boisées à l'échelle de la planète : usages conjoints pour la séquestration du carbone et la production d'énergie

The role of forest ecosystems in the regulation of greenhouse effect at the global scale is developed here, from two points of view, sometimes considered as opposed: carbon storage and wood production for energy. A nomenclature is proposed to understand all the various mechanisms implied in carbon storage. A comparison is made between the effects on carbon emissions of storage alone and storage with wood fuel production. Use of wood energy is proved to be a ‘bonus’ that could optimise, in the middle and long terms, the use of fossil fuel reserves. To cite this article: A. Prieur et al., C. R. Geoscience 336 (2004).     

An Integrated Ground Water Monitoring Program Using Multilevel Gas-Driven Samplers and Conventional Monitoring Wells

Hydrogeologic and ground water quality data obtained from a gas-driven multilevel sampler system and a polyvinyl chloride (PVC) monitoring well nest with the same aquifer communication intervals are compared. All monitoring points are in close proximity to each other. The study was conducted at an eight-acre uncontrolled hazardous waste site. The site is located in an alluvial valley composed of approximately 40 feet of alluvium overlying shale bedrock. The ground water at the site is contaminated with various organic constituents. A ground water monitoring network consisting of 26 conventional monitoring wells, nine observation well points, and six multilevel gas-driven samplers was established to characterize the hydrogeologic regime and define the vertical and horizontal extent of contamination in the vicinity of the abandoned chemical plant. As part of this study, a multilevel monitoring system was installed adjacent to a well nest. The communication zones of the multilevel samplers were placed at the same elevation as the sand packs of the well nest. The multilevel sampler system and well nest are located in a contaminated area directly downgradient of the site. A comparison of the vertical head distribution and ground water quality was performed between the well nest and the multilevel sampling system. The gas-driven multilevel sampling system consists of three gas-driven samplers that monitor separate intervals in the unconsolidated materials. The well nest, composed of two PVC monitoring wells in separate boreholes, has the same communication interval as the other two gas-driven samplers. Hydraulic head information for each multilevel sampler was obtained using capillary tubing. This was compared with heads obtained from the well nest utilizing an electric water level indicator. Chemical analyses from the PVC and multilevel sampler wells were performed and compared with one another. The analyses included organic acids, base neutrals, pesticides, PCBs, metals, volatile organics, TOX, TOC, CN, pH and specific conductance.     

Les consommations d'énergie dans le monde : une méthode robuste de prévision de leur évolution à moyen terme ; premières conséquences

This document proposes some ideas on the global energy context in an anthropogenic view: what are the needs in energy for the world population? How could they be satisfied in the middle term? What links exist with the near future of a necessarily limited system, the ‘Earth Surface, oceans and atmosphere’ system? Over past 30 years, the world individual energy consumption has been a constant. This is the basis of a robust method for predicting, in the short and middle term, the relative part of the main energy vectors and their interactions with the carbon cycle. Finally, some essential aspects of any energy planning are pointed out. To cite this article: M. Combarnous, A. Prieur, C. R. Geoscience 335 (2003).     

Distribution of sterol and fatty alcohol biomarkers in particulate matter from the frontal structure of the Alboran Sea (S.W. Mediterranean Sea)

Sterol and fatty alcohol biomarkers were analyzed in suspended and sinking particles from the water column (20–300 m) of the Almeria–Oran frontal zone to characterize the biogenic sources and biogeochemical processes. Diatom- and haptophyte-related sterols were predominant at all sites and vertical distributions of sterol, and fatty alcohol biomarkers in sinking particles were markedly different from suspended particles. In contrast to the relatively fresh sinking particles with elevated concentrations of phyto- and zooplanktonic sterols, suspended particles were extensively degraded with increasing depth and exhibited a more terrestrial and zooplanktonic signature with depth.Sterol and alcohol biomarkers distributions and δ¹³C values from the jet core and the associated gyre of Atlantic waters showed a decoupling between the sinking particles of 100- and 300-m depth, demonstrating the influence of lateral advection in the frontal zone. In contrast, vertical transport of the particulate organic matter in Mediterranean waters was interpreted from the similar isotopic and molecular composition at both depths. The high abundance of phytosterols and phytol below the euphotic zone at 100 m signified that downwelling of biomass occurred on the downstream side of the gyre. The high concentrations of phytosterols and POC, in combination with the high phytosterols/phytol ratio, indicated the accumulation of detrital plant material in the oligotrophic Mediterranean waters near the frontal zone.A higher contribution of phytol in the sinking particles collected during the night at the surface of the jet and at the upstream side of the gyre provided evidence of diel vertical zooplankton migration and important grazing by herbivorous zooplankton.Carbon isotope ratios of sterols confirmed that the 24-ethylcholest-5-en-3β-ol, commonly associated with terrestrial sources, was a substantial constituent of the phytoplankton in this area. However, the more δ¹³C depleted values obtained for this compound in suspended particles suggested that there was some terrestrial contribution that only becomes evident after degradation of the more labile marine organic matter.