Assessment of the effects of hydrocarbon contamination on the sedimentary bacterial communities and determination of the polar lipid fraction purity: Relevance of intact phospholipid analysis

This in situ study reports on the relevance of intact phospholipids as new biomarkers and highlights the limits of the classical fatty acid analysis after the hydrolysis of the polar lipid fraction. The analysis of polar lipid fractions revealed significant contributions of marine macrophytes with either non-phospholipid compounds (sulfoquinovosyl diacylglycerol) or with both non-bacterial phospholipid classes (phosphatidylcholine) and non-bacterial phospholipid molecular species (some molecular species of phosphatidylglycerol). The analysis of intact phospholipids showed also the predominance of gram-negative bacteria in sediments whereas the analysis of fatty acids alone cannot confirm such information. Lastly, as regard to the effects of petroleum hydrocarbons on the sedimentary bacterial communities, we observed a higher degree of saturation of the fatty acyl chains of the phospholipids extracted from sediment exposed to a massive and chronic crude oil contamination. Such a result was interpreted as an adaptive response resulting in higher membrane rigidity of the bacterial communities.     

Tectonic Significance of the Taitung Canyon, Huatung Basin, East of Taiwan

Since the beginning of formation of Proto-Taiwan, the subducting Philippine (PH) Sea plate has moved continuously through time in the N307° direction with respect to Eurasia (EU), tearing the EU plate. The subducting EU plate includes a continental part in the north and an oceanic part in the south. The boundary B between these two domains corresponds to the eastern prolongation of the northeastern South China Sea ocean-continent transition zone. In the Huatung Basin (east of Taiwan), the Taitung Canyon is N065° oriented and is close and parallel to B. Seismic profiles show that the southern flank of the canyon corresponds to a fault with a normal component of a few tens of meters in the sediments and possible dextral shearing. Several crustal earthquakes of magnitude >%6 are located beneath the trend of the Taitung Canyon and focal mechanisms suggest that the motion is right-lateral. Thus, faulting within the sedimentary sequence beneath the Taitung Canyon is a consequence of underlying dextral strike-slip crustal motions. As the continental part of the EU slab located north of B has been recently detached, some subsequent dextral strike-slip motion might be expected within the EU slab, along the ocean-continent transition zone, which is a potential zone of weakness. We suggest that the dextral strike-slip motion along the ocean-continent boundary of the EU slab might trigger the observed dextral strike-slip motion within the overlying PH Sea crust and the associated faulting within the sediments of the Huatung Basin, beneath the Taitung Canyon. An erratum to this article is available at .     

Cross-scale analysis of cluster correspondence using different operational neighborhoods

Cluster correspondence analysis examines the spatial autocorrelation of multi-location events at the local scale. This paper argues that patterns of cluster correspondence are highly sensitive to the definition of operational neighborhoods that form the spatial units of analysis. A subset of multi-location events is examined for cluster correspondence if they are associated with the same operational neighborhood. This paper discusses the construction of operational neighborhoods for cluster correspondence analysis based on the spatial properties of the underlying zoning system and the scales at which the zones are aggregated into neighborhoods. Impacts of this construction on the degree of cluster correspondence are also analyzed. Empirical analyses of cluster correspondence between paired vehicle theft and recovery locations are conducted on different zoning methods and across a series of geographic scales and the dynamics of cluster correspondence patterns are discussed.      

Hazard appraisal and hazard-zone mapping of flooding and debris flowage in the Rio Combeima valley and Ibague city,Tolima Department,Colombia

Since a state law issued in 1989, every big town in Colombia has to promote its own preparedness programme for disaster relief in the framework of the Oficina Nacional para la Atencion de Desastres (1987). Such a programme includes a very detailed hazard-zone map for flooding and debris flows in the densely inhabited suburbs of Ibagué city (capital of Tolima Department), as well as enquiries about risk knowledge and consciousness among people who live at high risk. We stress the fact that both detailed hazard-zone maps and enquiries should be closely undertaken at the same time, and that distinguishing previous knowledge, existing consciousness and risk perception to forecast the behaviour of people and of the community in case of disaster, are criteria for a better risk assessment.     

Simultaneous H and K Ca ii,h and k Mg ii,Lα and Lβ H i profiles of the April 15, 1978 solar flare observed with the OSO-8/L.P.S.P. experiment

Solar flare observations have been performed with the multichannel L.P.S.P. experiment on board OSO-8 NASA Satellite. Simultaneous H and K Caii, h and k Mgii, L and L Hi profiles have been recorded on the plage just before the flare, during the flare onset and relaxation phases. The different behaviour of line profiles and intensities during the flare is evidenced and indicates a downward propagation with relaxation times increasing from the upper part to the lower part of the chromosphere related to line formation processes. Using the H observed profile, an upper limit of 8 × 10¹³ cm^-3 is derived for the electron density.     

O VI (λ = 1032 Å) profiles in and above an active region prominence,compared to quiet Sun center and limb profiles

O vi ( = 1032 Å) profiles have been measured in and above a filament at the limb, previously analyzed in H i, Mg ii, Ca ii resonance lines (Vial et al., 1979). They are compared to profiles measured at the quiet Sun center and at the quiet Sun limb.Absolute intensities are found to be about 1.55 times larger than above the quiet limb at the same height (3); at the top of the prominence (15 above the limb) one finds a maximum blue shift and a minimum line width. The inferred non-thermal velocity (29 km s^–1) is about the same as in cooler lines while the approaching line-of-sight velocity (8 km s^–1) is lower than in Ca ii lines.The O vi profile recorded 30 above the limb outside the filament is wider (FWHM = 0.33 Å). It can be interpreted as a coronal emission of O vi ions with a temperature of about 10⁶ K, and a non-thermal velocity (NTV) of 49 km s^–1. This NTV is twice the NTV of quiet Sun center O vi profiles. Lower NTV require higher temperatures and densities (as suggested by K-coronameter measurements). Computed emission measures for this high temperature regime agree with determinations from disk intensities of euv lines.     

OSO-8 observations of CaII H and K,MgII h and k,Lα and Lβ above a sunspot

Observations with the French (L.P.S.P.) experiment on board OSO-8 of a sunspot and nearby plage region are described. The behaviour of the emission cores of the Ca II H and K and Mg II h and k resonance lines is very similar and the correspondence in intensity between the four lines persists in all observed features. In contrast, the Lyman lines show little correlation with the other lines. Their emission regions appear broader in the spectroheliograms than the underlying sunspot structure and must not necessarily possess a counterpart in lower layers. From the central intensity of L above the umbra an electron density of 4.3 × 10¹⁰ cm^-3 n _e ^* 2.3 × 10¹¹ cm^-3 at 20 000 K is estimated.Mitteilungen aus dem Kiepenheuer-Institut Nr. 186.Stockholm Observatorium, S-13300 Saltsjöbaden, Sweden.Laboratoire de Physique Stellaire et Planétaire, CNRS, P.O. Box 10, F-91370 Verrières-le-Buisson, France.     

Les failles récentes des Grands-Moulins (Savoie) : un Sackung (tassement gravitaire) majeur dans les Alpes françaises

In Savoy, the Grands-Moulins recent fault scarps, previously interpreted as seismic fault ruptures, are in fact part of a major Sackung (deep seated gravitational spreading) of the French Alps (9 km long). We mapped more than 60 sackung scarps, some of them reaching 1330 m long and 30 m high. These antislope scarps stop the active screes and offset relict Dryassic rock glaciers by 16 m. We present geomorphologic observations attesting for their gravitational origin. This Sackung is primarily due to glacial debuttressing, while seismic shaking could be a triggering mechanism. To cite this article: J.-C. Hippolyte et al., C. R. Geoscience 338 (2006).