The Meriadzek Terrace: A marginal plateau

The Meriadzek Terrace forms part of the continental margin in the Bay of Biscay at a depth between that of the Continental shelf and the abyssal plain. Reflection profiles show that it is bounded on either side by basement ridges with a sediment infill between the ridges. It was probably formed by downfaulting of the continental shelf, possibly connected with the opening of the Bay of Biscay.     

Meiofauna of the deep Eastern Mediterranean Sea: distribution and abundance in relation to bacterial biomass, organic matter composition and other environmental factors

Quantitative information on the abundance and biomass of metazoan meiofauna was obtained from samples collected at 15 deep-sea stations in the Eastern Mediterranean Sea (533–2400m). Meiofaunal abundance was compared to bacterial biomass and other environmental factors such as the total sedimentary organic matter content, the concentrations of the main biochemical classes of organic compounds (i.e. proteins, carbohydrates and lipids) and to ATP. To estimate the sedimentation potential of primary organic matter, sediment bound chloroplastic pigment equivalents (CPE) were assayed. Meiofaunal density was very low ranging from 4 ind.10cm⁻² (Station A4, 1658m depth) to 290 ind.10cm⁻² (Station A12, 636m depth). Nematodes were the numerically dominant taxon (68% of total meiofauna) and were usually confined to the top 6cm of the sediments. Total meiofaunal biomass ranged from 2.78μgC 10cm⁻² (Station A4) to 598.34μgC 10cm⁻² (Station 15A). There was a significant decrease in the density of metazoan meiofauna with water depth. Bacterial biomass largely dominated the total biomass (as the sum of bacterial and meiofaunal biomass) with an average of 73.2% and accounted for 35.8% of the living biomass (as ATP carbon) whereas meiofaunal biomass accounted only for 6.56%. Bacterial biomass was significantly related to the DNA concentrations of the sediment. A significant correlation between ATP concentration and CPE content was also found. No correlations were found between meiofauna, ATP and CPE, or between meiofauna and bacterial parameters. The significant relationship between meiofaunal density and the ratio of labile organic matter/total organic matter indicates that deep-sea meiofauna inhabiting an extremely oligotrophic environment (such as the Eastern Mediterranean) may be more nutritionally dependent upon the quality than on the quantity of sedimentary organic matter.     

Estimating the dispersion of biostratigraphic events in the subsurface by graphic correlation: an example from the Late Jurassic of the Wessex Basin, UK

The strikingly cyclic character of digitally filtered gamma ray logs from the Oxfordian to Portlandian interval of the Wessex Basin, onshore United Kingdom, facilitates high resolution log correlation over considerable distances, allowing the systematic calibration of biostratigraphic with lithostratigraphic data through graphic correlation. This involves the systematic cross-plotting of biostratigraphic events, based on samples taken from cuttings and sidewall cores, from a set of wells to produce a composite standard. Initially the standard is a single well, chosen for maximum thickness and completeness. Biostratigraphic events are added to by drawing lines of correlation and projecting the data points onto the composite standard. The scatter of biostratigraphic events is generally such that a line of correlation cannot be drawn with confidence from the biostratigraphic data alone. Independent lines of correlation are established between wells by first matching cycles (? parasequences) on digitally filtered gamma ray traces and using these as a framework for adding biostratigraphic events to the composite standard. This has advantages over the conventional approach in that the effects of outliers in the data are minimized and hiatuses and subtle changes in rock accumulation rates become apparent. By adding all the biostratigraphic events from all wells to the composite standard a range chart is produced depicting the scatter or dispersion of all biostratigraphic events relative to the log based cycles. The end result is an integrated stratigraphy in which biostratigraphic events are calibrated against rock events giving a measure of dispersion, and hence confidence, for each biostratigraphic event.     

Political transformation,urban policy and the state in London's Docklands

The contemporary restructuring of urban space in the United Kingdom can be understood in terms of much broader social, political, and economic changes. This paper provides an analysis of this experience in London's Docklands, as a way of highlighting the connections between these social relations. We can best understand these changes by drawing upon regulation theory, which posits a firm, but dynamic, link between economic and political processes. Through an analysis of urban policy changes, political struggles, and economic shifts in London's Docklands, I argue for a more central role for the state and social movements in the understanding of social regulation and urban change. Finally, the paper considers the establishment of an Urban Development Corporation in the area in 1981, which represents an attempt by the central government to establish a new regime of economic and political life in the area. This has produced important conflicts at a local level, which typify the conflictual nature of attempts to restructure the economic and political relations of urban locales.     

Isotopic abundances of silicon in four red giants

High-resolution spectra near 4 m of the four red giants— Peg,o ¹ Ori, 10 Dra, and HR 1105—have been analysed to obtain estimates of the²⁸Si/²⁹Si and²⁸Si/³⁰Si abundance ratios. For Peg and the S star HR 1105, the²⁸Si/²⁹Si ratio is close to the solar ratio (²⁸Si/²⁹Si=20).²⁹Si appears to be underabundant in the MS staro ¹ Ori (²⁸Si/²⁹Si=40) and the M star 10 Dra (²⁸Si/²⁹Si53). The³⁰Si isotope appears to be underabundant by, perhaps, about a factor of 2 in all four stars.     

Solar rotation from a number of fraunhofer lines

Solar differential rotation for 1982–83 obtained at the double pass spectrograph of the McMath telescope at Kitt Peak, are presented for lines of Fe, Mg, Na, K, Si, and O in the wavelength interval 3820–10827. The results are analyzed by representations in Legendre polynominals and a power series. The differential rotation is very close to the result obtained by Howard and Harvey in 1966–68 at Mt. Wilson but with a slightly greater amplititude. We find a mean equatorial rate of rotation of 1.977 km s^-1. Day to day variations are observed in the equatorial zone; a stable rate of rotation is observed outside of the sunspot zone.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.     

Photospheric electric current and transition region brightness within an active region

Distributions of vertical electric current density (J _z) calculated from vector measurements of the photospheric magnetic field are compared with ultraviolet spectroheliograms to investigate whether resistive heating is an important source of enhanced emission in the transition region. The photospheric magnetic fields in Active Region 2372 were measured on 6 and 7 April, 1980 with the MSFC vector magnetograph; ultraviolet wavelength spectroheliograms (L and Nv 1239 Å) were obtained with the UVSP experiment aboard the Solar Maximum Mission satellite. Spatial registration of the J _z (5 arc sec resolution) and UV (3 arc sec resolution) maps indicates that the maximum current density is cospatial with a minor but persistent UV enhancement, but there is little detected current associated with other nearby bright areas. We conclude that although resistive heating may be important in the transition region, the currents responsible for the heating are largely unresolved in our measurements and have no simple correlation with the residual current measured on 5 arc sec scales.National Research Council Resident Research Associate.National Oceanic and Atmospheric Administration Space Environment Laboratory; currently at MSFC/SSL.     

A decade of cost-reduction in very large telescopes (The SST as prototype of special-purpose telescopes)

Many design and technical innovations over the past ten or fifteen years have reduced the costs of very large telescopes by nearly an order of magnitude over those of classical designs. Still a further order of magnitude reduction is possible if the telescope is specialized for on-axis spectroscopy, giving up especially the luxuries of wide field, multiple focal positions, and access to all the sky at will. The SST (Spectroscopic Survey Telescope) with use eighty-five 1 m circular mirrors mounted in a steel frame composed of hundreds of interlocking tetrahedrons, keeping a fixed elevation angle of 60° with rotation only in azimuth. Using an optical fiber it will feed as much light to spectrographs as can be done by a conventional 8 m telescope, yet has a target basic completion cost of only $6 million.Paper presented at the Symposium on the JNLT and Related Engineering Development, Tokyo, November 29–December 2, 1988.     

Late‐Holocene wind‐field evolution at the southern Baltic coast as revealed by GPR data from the Mrzeżyno dunefield,NW Poland

All dunes within a dunefield usually show a similar response to the wind regime. However, in the late‐Holocene coastal dunefield in NW Poland the surface topography suggests that slipface orientation may vary significantly with distance from the coast, which is rarely reported in the literature. The dunefield was stabilized with forest in the mid‐19th century, preserving a unique record of atmospheric circulation in the South Baltic region at the end of the Little Ice Age. To elucidate the Holocene processes occurring along the study site a pseudo‐3D GPR data set was collected. Six grids of parallel GPR lines combined with 400 m of GPR profiles (2D) were collected across the dunefield and displayed using GOCAD for interpretation and geostatistical analysis. The geophysical data revealed that the larger dunes almost entirely consist of steeply laminated facies. Most importantly the pseudo‐3D data, supported by geostatistical estimates of strata dip directions, revealed the existence of three zones parallel to the coastline with the mean dip direction almost perpendicular to the coast in the northern coastal strip and almost parallel to it in the southern part. Spreads of the dip directions in pseudo‐3D GPR data sets recorded on the stoss slopes of dunes and crests suggested initial deposition on transverse dunes, which later were transformed into barchanoid dunes. This can probably be linked to changes in the wind regime, i.e. reduction in velocity of the northern and northwestern winds leading to reduced sediment supply from the coast. While the data provide a new interpretation of Holocene dunefield dynamics at this site, they also suggest that the minimum number of pseudo‐3D GPR grids required to establish general trends using geostatistical analysis should be at least 10, with even more data needed at larger, or more complex dunefields.