Small towns as ‘sub-poles’ in English rural development: Investigating rural–urban linkages using sub-regional social accounting matrices

This paper uses spatial economic data from four small English towns to measure the strength of economic integration between town and hinterland and to estimate the magnitude of town–hinterland spill-over effects. Following estimation of local integration indicators and inter-locale flows, sub-regional social accounting matrices (SAMs) are developed to estimate the strength of local employment and output multipliers for various economic sectors. The potential value of a town as a ‘sub-pole’ in local economic development is shown to be dependent on structural differences in the local economy, such as the particular mix of firms within towns. Although the multipliers are generally small, indicating a low level of local linkages, some sectors, particularly financial services and banking, show consistently higher multipliers for both output and employment.     

Tectonic impact on the Lake Sevan environment (Armenia)

 The geology of Lake Sevan is characterized by the structure of a pull-apart basin. Methane emission from the lake surface correlates with evidence of physical and chemical water properties, remote sensing, etc., and suggests its possible emission from active fault zones at the lake bottom, as well as emission of biogenic methane from the fermentation of bottom organic remains. Correlation with anomalies in the lake bottom geochemistry suggests a high permeability of active fault zones and suggests that geodynamic, seismic and geochemical activity across the fault zones during the buildup to the M=7.1 Spitak earthquake led to plankton depression, which resulted in a large number of fish dying in 1984, and ended with a seismic disaster in 1988. Received: 2 November 1999 · Accepted: 27 January 2000     

A derivation of the Isted formula for average mineral grade of a triangular prism

The Isted formula, which provides an exact calculation of the spatial average of mineral grade in a triangular prism under the assumption of linear change, is derived, and its limitations outlined. This formula may be used to estimate the mean of any trivariate function whenever variation in the vertical direction can be considered negligible.     

An atlas of photospheric magnetic field observations and computed coronal magnetic fields: 1976–1985

Daily magnetogram observations of the large-scale photospheric magnetic field have been made at the John M. Wilcox Solar Observatory at Stanford since May of 1976. These measurements provide a homogeneous record of the changing solar field through most of solar cycle 21.Using the photospheric data, the configuration of the coronal and heliospheric fields can be calculated using a Potential Field - Source Surface model. This provides a three - dimensional picture of the heliospheric field evolution during the solar cycle.In this note we announce the publication of UAG Report No. 94, an Atlas containing the complete set of synoptic charts of the measured photospheric magnetic field, the computed field at the source surface, and the coefficients of the multipole expansion of the coronal field. The general underlying structures of the solar and heliospheric fields, which determine the environment for solar-terrestrial relations and provide the context within which solar activity related events occur, can be approximated from these data.     

Biomonitoring of heavy metal availability in the marine environment

Biomonitors can be used to establish geographical and/or temporal variations in the bioavailabilities of heavy metals in the marine environment, offering time-integrated measures of those portions of the total ambient metal load that are of direct ecotoxicological relevance. Heavy metal biomonitors need to conform to certain required characteristics, not least being metal accumulators. Use of a suite of biomonitors allows recognition of the presence and relative magnitude of different metal sources. For example, a macrophytic alga responds essentially to dissolved metal sources only, a suspension feeder like a mussel responds to metal sources in dissolved and suspended phases, and a deposit feeder responds to metal available in the sediment. Examples are given of suitable heavy metal biomonitors in the coastal waters of Europe, New Zealand, Hong Kong and China. It is not valid to compare absolute accumulated metal concentrations in biomonitors interspecifically, although interspecific comparisions of rank orders do allow cross correlations of relative bioavailabilities of heavy metals to different biomonitors at the same sites. There is a need to identify widespread cosmopolitan biomonitors to allow intra-specific comparisons of bioavailabilities between geographical areas. Such cosmopolitan biomonitors may include the alga Ulva lactuca, mussels of the genera Mytilus and Perna, the oysters Ostrea and Crassostrea, barnacles like Balanus amphitrite and Tetraclita squamosa, and the talitrid amphipod Platorchestia platensis. A major caveat in the use of such cosmopolitan biomonitors remains the need for reliable, specific taxonomic identification.     

Chlorinated pesticides and PCBs in the sea-surface microlayer and seawater samples of Singapore

Sea-surface microlayer (SML) and seawater samples collected from Singapore's coastal marine environment were analyzed for selected chlorinated pesticides and polychlorinated biphenyls (PCBs). The SML is a potential site of enrichment of persistent organic pollutants (POPs) compared to the underlying water column. The concentration ranges of SigmaHCH, SigmaDDT and SigmaPCB in subsurface (1 m depth) seawater were 0.4-27.2 ng/l (mean 4.0 ng/l), 0.01-0.6 ng/l (mean 0.1 ng/l) and 0.05-1.8 ng/l (mean 0.5 ng/l) respectively. In the SML, the concentration ranges of SigmaHCH, SigmaDDT and SigmaPCB were 0.6-64.6 ng/l (mean 9.9 ng/l), 0.01-0.7 ng/l (mean 0.2 ng/l) and 0.07-12.4 ng/l (mean 1.3 ng/l) respectively. High spatial and temporal distribution was observed for all POPs measured. However, overall levels measured in the SML were lower than levels reported in the literature for SML samples from temperate coastal regions-possibly due to loss of semi-volatile compounds in the tropical climate of Singapore. Atmospheric wet deposition during the monsoon season may be an important source of POPs to the SML. This study provides the first scientific data on POP concentrations and enrichment factors in the SML for Southeast Asia.     

Improved stepwise solvent extraction scheme for geochemical trace analysis using flame atomic absorption

A solvent extraction, flame atomic absorption analytical scheme is reported for the elements Au, Tl, Sb, Ga, Mo, Cu, Ni, Co, Ag, Bi, Cd, Pb, Zn and Mn in geological materials. Results are quoted for NIM standard rocks and for USGS reference samples, and are compared with published values; practical detection limits are generally better than 0.2 ppm. A stepwise solvent extraction and preconcentration process is utilised (chloro complexes, diethyldithiocarbamate and 8-hydroxyquinoline chelates are used with methyl isobutyl ketone and $\text{n-}\text{butyl}$ acetate as solvents) which allows the reproducible isolation of groups of elements which generally occur at similar concentrations geologically. Analytical accuracy is maintained by the chemical elimination, within each step, of other chelate-forming elements present at higher concentrations which would cause spectral interferences during the atomic absorption measurements. The complete stepwise process is reported together with elemental partition data which covers a range of aqueous ionic conditions.     

Multi-channel magnetograph observations

A new technique for displaying magnetograph observations is presented and applied to the 12-channel magnetograph at Kitt Peak National Observatory. Using the data from a raster scan, a digital spectroheliogram is constructed on the face of a cathode ray tube and photographed. This enables one to recognize patterns in magnetograph data as easily as with conventional photographs. Comparisons with simultaneous spectroheliograms show no qualitative differences and indicate that the magnetograph is quite capable of studying morphology of individual solar features.Kitt Peak National Observatory Contribution No. 499.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.