Strategic planning and urban restructuring: the case of Pyrmont‐Ultimo

The City West Urban Strategy is concerned with redevelopment in part of inner metropolitan Sydney. Such plans should not be seen in isolation, but in a wider temporal and spatial context. Pyrmont and Ultimo have been undergoing significant socioeconomic changes for a decade and this trend is likely to be reinforced and intensified if the Strategy is implemented. Also the recent and projected changes are consistent with a global pattern of restructuring in urban waterfront areas where former port and industrial functions have declined.     

Radio sources in the 2dF Galaxy Redshift Survey – II. Local radio luminosity functions for AGN and star-forming galaxies at 1.4 GHz

We have cross-matched the 1.4-GHz NRAO VLA Sky Survey (NVSS) with the first 210 fields observed in the 2dF Galaxy Redshift Survey (2dFGRS), covering an effective area of 325 deg² (about 20 per cent of the final 2dFGRS area). This yields a set of optical spectra of 912 candidate NVSS counterparts, of which we identify 757 as genuine radio identifications – the largest and most homogeneous set of radio source spectra ever obtained. The 2dFGRS radio sources span the redshift range     to 0.438, and are a mixture of active galaxies (60 per cent) and star-forming galaxies (40 per cent). About 25 per cent of the 2dFGRS radio sources are spatially resolved by NVSS, and the sample includes three giant radio galaxies with projected linear size greater than 1 Mpc. The high quality of the 2dF spectra means we can usually distinguish unambiguously between AGN and star-forming galaxies. We make a new determination of the local radio luminosity function at 1.4 GHz for both active and star-forming galaxies, and derive a local star formation density of         .     

Interannual fluctuations in the density of sand lance,Ammodytes americanus,larvae in Long Island Sound, 1951–1983

Enumeration data from over 2,300 ichthyoplankton samples collected during 17 yr, spanning a 32-yr interval (1951–1983), were compiled to determine interannual variations in density of sand lance larvae. Years of relatively high densities were noted during the winters of 1965–1966 and 1978–1979 and low densities in 1971–1974. A regular increase in numbers during the late 1970’s and the peak in 1978–1979 coincided with increases in population size found throughout the coastal northwest Atlantic Ocean. Densities in Long Island Sound began to decline in 1980 and this continued through 1983. In contrast, densities throughout coastal Atlantic areas during the 1980’s remained at least as high as they were 1976–1978. Interannual fluctuations in density of sand lance larvae could be partially explained by water temperatures in December. Warm Decembers were associated with low larval densities.     

Racemization of amino acids in marine sediments determined by gas chromatography

Ratios of d- to l-amino acids in acid hydrolysates from foraminifera of two deep-sea cores from the Caribbean Sea and Atlantic Ocean increase with depth and consequently with age over a span from 40,000 to 2,000,000 yr. The changing ratios do not seem to follow first-order reversible rate laws. Valine, leucine and glutamic acid apparently racemize (isoleucine epimerizes) at slower rates than do phenylalanine, alanine, aspartic acid and proline. The general relative order for rates of racemization of total (free and bound) amino acids may depend on the electron-withdrawing capacity of the R substituents of the amino acids and on the rates with which the amino acids are naturally hydrolyzed. In contrast to the total amino acids, the free amino acids in these samples are more extensively racemized, probably as a result of various catalytic and hydrolytic reactions.Previous related work based on ion-exchange chromatography has considered only ratios of alloisoleucine to isoleucine. With the gas chromatographic method used here, d/l ratios of all common asymmetric amino acids can be estimated. Measurement of the extent of racemization of amino acids in marine sediments seems to provide the basis for a geochronological tool covering the last few million years.     

Symposium über Fragen der Cyanophytentaxonomie im Seenforschungsinstitut der ETHZ/EAWAG in Kastanienbaum (Schweiz), 2.–15. August 1979 Verhandlungsbericht

The 8th Symposium of the International Association for Cyanophyte Research IAC was attended by 29 specialists from 11 countries. The 19 oral presentations and discussions centered on the following themes: The basic principles of cyanophyte taxonomy (3 lectures), systematic problems of certain taxonomic groups (5 lectures), morphology (6 lectures) and ecology (5 lectures). The intensive discussions between representatives of the classical (european) taxonomic treatment of cyanophytes (based on morphological and ecological characteristics) and those representing the bacteriological study of ‘cyanobacteria’ were especially valuable. The central theme of the meeting was, however, the mutual microscopic study and discussion of problematic blue-greens from natural habitats, that were mostly collected during the three field trips into different areas of central Switzerland (Grimsel-Gotthard-Nufenen. Klewenalp. Gerzensee).      

Diffusion-controlled growth of albite and pyroxene reaction rims

The growth rates of albite and pyroxene (enstatite + diopside + spinel) reaction rims were measured at 1000°C and ˜700 MPa and found to be parabolic indicating diffusion-controlled growth. The parabolic rate constants for the pyroxene (+ spinel) rims in samples with 0.5 wt% H₂O added or initially vacuum dried at 25°C and 250°C are 1.68 ± 0.09, 0.54 ± 0.05 and 0.25 ± 0.06 μm²/h, respectively. The values for albite rim growth in samples initially dried at 60°C and with 0.1 wt% H₂O added are 0.25 ± 0.04 and 0.33 ± 0.03 μm²/h, respectively. The latter values were used to derive the product of the grain boundary diffusion coefficient D′_A, where A = SiO₂, NaAlO₂, or NaAlSi₋₁, and the grain boundary thickness δ in albite. The calculated D′_SIO2δ in the albite aggregate for the situations of two different water contents are about 9.9 × 10⁻²³ and 1.4 × 10⁻²² m³ s⁻¹, respectively. Both the rate constants and the calculated D′_Aδ demonstrate that the effect of water content on the grain boundary diffusion rate in monomineralic albite and polymineralic pyroxene (+ spinel) aggregates is small, consistent with recent studies of monomineralic enstatite and forsterite rims. Received: 1 July 1995 / Accepted: 1 August 1996     

Use of statistical analysis to formulate conceptual models of geochemical behavior: water chemical data from the Botucatu aquifer in São Paulo state, Brazil

Water chemical data from the Botucatu Sandstone aquifer in the São Paulo State part of the Paraná Basin, Brazil, was evaluated using geochemical methods and two statistical analyses: cluster analysis and factor analysis. The results were used to develop a conceptual geochemical model, in which three geochemical regions were identified, and their chemical behavior was modeled. The characteristic chemicals, changing from the recharge area to the center of the basin, are: SiO₂—(HCO₃⁻ and Ca²⁺)—(Na⁺, CO₃²⁻, and SO₄²⁻). The distribution of the chemicals is interpreted as controlled by different water–rock interaction processes in the different regions. In the recharge area, dissolution of alkali–feldspar minerals in the sandstone is the main reaction observed; in the mid-section of the basin, calcite dissolution results in high calcium and bicarbonate concentration; in the center of the basin, leakage from underlying layers becomes the governing factor.     

The southwest Indian Monsoon over the last 18 000 years

Previously published results suggest that the strength of the SW Indian Monsoon can vary significantly on century- to millenium time scales, an observation that has important implications for assessments of future climate and hydrologic change over densely populated portions of Asia. We present new, well-dated, multi-proxy records of past monsoon variation from three separate Arabian Sea sediment cores that span the last glacial maximum to late-Holocene. To a large extent, these records confirm earlier published suggestions that the monsoon strengthened in a series of abrupt events over the last deglaciation. However, our data provide a somewhat refined picture of when these events took place, and suggest the primacy of two abrupt increases in monsoon intensity, one between 13 and 12.5 ka, and the other between 10 and 9.5 ka. This conclusion is supported by the comparisons between our new marine data and published paleoclimatic records throughout the African-Asian monsoon region. The comparison of data sets further supports the assertion that maximum monsoon intensity lagged peak insolation forcing by about 3000 years, and extended from about 9.5 to 5.5 ka. The episodes of rapid monsoon intensification coincided with major shifts in North Atlantic-European surface temperatures and ice-sheet extent. This coincidence, coupled with new climate model experiments, suggests that the large land-sea thermal gradient needed to drive strong monsoons developed only after glacial conditions upstream of, and on, the Tibetan Plateau receded (cold North Atlantic sea-surface temperatures, European ice-sheets, and extensive Asian snow cover). It is likely that abrupt changes in seasonal soil hydrology were as important to past monsoon forcing as were abrupt snow-related changes in regional albedo. Our analysis suggests that the monsoon responded more linearly to insolation forcing after the disappearance of glacial boundary conditions, decreasing gradually after about 6 ka. Our data also support the possibility that significant century-scale decreases in monsoon intensity took place during the early to mid-Holocene period of enhanced monsoon strength, further highlighting the need to understand paleomonsoon dynamics before accurate assessments of future monsoon strength can be made.     

Quaternary evolution of ephemeral playa lakes on the Southern High Plains of Texas, USA: cyclic variation in lake level recorded in sediments

Ephemeral playa lakes on the Southern High Plains northeast of Amarillo, Texas, are underlain by more than 10 m of Quaternary lake deposits. Sediments beneath 12 lakes were examined in 76 hollow-stem auger cores and in excavations. Stacked depositional cycles recognized in lake sediments record repeated phases of (1) initial highstand, (2) ephemeral lake, and (3) lake shrinkage and prolonged exposure. Sedimentary and soil structures show that during all phases the lakes were ephemeral, but that the duration and frequency of flooding varied, which caused variation in the relative amounts of accumulation, deflation, and soil formation. The highstand phase is documented by wave-cut benches and lake sediments that extend beyond present lake margins. Mud transported as suspended load was deposited from ponded water. Desiccation resulted in mudcracks and allowed deposition of eolian sand, but exposure episodes were relatively short or infrequent, and vertic soil formation, oxidation of organic material, and deflation of sand were minimal. Decreased frequency and duration of flooding resulting in increased pedogenic modification under conditions similar to those under which modern playa lake sediments accumulate. Eolian silt deposited on dry lake beds and clays deposited in flooded lakes were mixed by vertic soil processes during repeated wetting and drying. Organic material was partly oxidized and partly translocated down roots and cracks, and interbedded upland facies were gleyed. Episodes of lake shrinkage and more frequent exposure are recorded by reddening and formation of calcic horizons within lake muds. Red-brown eolian loam prograded across lake sediments, and calcic soils developed on it. These grassland slope facies record decrease in the size of the playa lakes.