In situ mapping of growth lines in the calcitic prismatic layers of mollusc shells using X-ray absorption near-edge structure (XANES) spectroscopy at the sulphur K-edge

The microstructure and composition, including chemical speciation of sulphur (S), of two mollusc shells were investigated using a combination of scanning electron microscopy, X-ray absorption near-edge structure spectroscopy (XANES) and electron probe microanalysis (EPMA). The shell of Pinna is composed of monocrystalline, and Pinctada, of polycrystalline, calcite prisms separated by organic-rich walls. Sulphur speciation information from XANES spectra using a scanning X-ray microscope showed that the protein S content of the interprismatic walls is higher than the SO₄ content, whereas the reverse is true for the intraprismatic structures. High-spatial-resolution XANES maps for the different S species across adjacent calcite prisms confirm their distinctive distributions in the molluscan shells and illustrate the presence of narrow, submicron transverse growth features. On a larger scale, a series of wider growth zones, incorporating the submicron zones, are aligned parallel to each other and cross-cut many calcite prisms. EPMA element maps for magnesium (Mg) and S demonstrate that these growth increments are compositionally zoned, comprising alternating layers of high mineral (Mg-rich) and high organic (S-rich) components. Additionally, these maps confirm that the organic interprismatic walls have lower Mg and higher S than the intraprismatic structures.     

The Governance of sustainable development in Wales

A new institutional architecture is emerging in Wales to govern sustainable development. The National Assembly for Wales (hereafter referred to as the 'Welsh Assembly')1 has a statutory duty to promote sustainable development in the exercise of all its functions; its response has been to design a set of political and organizational arrangements to manage this policy area, and to prepare a Scheme that sets out how it proposes to discharge this duty. Devolved government in Wales has also been the catalyst for the emergence of collaborative relationships and partnerships between different sectors and interests. The Welsh Assembly and the Welsh Local Government Association have published a Compact jointly committing them to promote sustainable development; national non-governmental organizations such as Oxfam and the World Wide Fund for Nature have set up Welsh agencies; local government sustainable development coordinators have formed a national network; a national Sustainable Development Forum has been created; and the Welsh Assembly has taken the lead in establishing a European network of countries interested in sharing best practice on sustainable development. A new Wales-specific structure and system is materializing and the test now is how far this will be effective in delivering sustainable development policies and solutions at local and national levels. This paper examines the challenges in managing sustainable development, and the potential for success of this new governance system, drawing on recent research undertaken by the author on behalf of the Joseph Rowntree Foundation. The examination is set in the context of different theories of governance, and sustainable development is conceptualized as a 'wicked issue'—one that cannot be resolved by organizations and agencies acting autonomously, but rather needs concerted focus and action across all sectors.     

Identification of haemocytes and their role in clotting in the blue crab,Callinectes sapidus

Three types of haemocyte — hyaline cells, small granule and large granule haemocytes — have been identified in the circulation of blue crabs, Callinectes sapidus Rathbun, that were collected and processed in North Carolina, USA in February 1991. Differentiation of haemocytes begins in the haematopoietic tissue and continues in the circulation. Hyaline cells are distinguished morphologically by their relatively small size, high nucleocytoplasmic ratio and sparse cytoplasmic granule content. Small and large granule haemocytes are distinguished, respectively, by a preponderance of small and large electron dense granules in their cytoplasm. Furthermore, a light and electron microscopic examination of the clotting process performed in July 1991 revealed that hyaline cells initiated coagulation when exposed to seawater, whereas granular haemocytes did not undergo marked changes when so treated. These distinct functional and morphologic features suggest that the hyaline cell and granular haemocytes represent distinct cell lines. It remains unclear whether small granule haemocytes differentiate into large granule haemocytes.     

An investigation into the kerbside recycling behaviour of two Welsh case study authorities.

This paper investigates the number of observed households setting out their containers for kerbside recyclable collection in two Welsh kerbside recycling programmes; namely, Rhondda Cynon Taf County Borough Council and Caerphilly County Borough Council. Analysed data from the monitoring of approximately 114 000 households in the two separate kerbside programmes are presented, making this the largest study of kerbside recycling behaviour in the UK. The average household set-out rates of individual households per electoral division and per street in each programme were compared. Average household set-out rate for a particular electoral division and street was then related to certain socio-economic indicators. The study was performed using the 'ArcView' geographical information systems (GIS) package. The model identified a moderate link between household set-out rate (%) and socio-economic status at electoral division level. However, there was no correlation between socio-economic status and average household set-out rate in a street. Household set-out rates for both programmes fluctuated significantly in streets with similar socio-economic status. Another significant factor affecting set-out rate, herein named the 'Nant-y-Gwyddon effect', is also described.     

Using foraging honeybees to sample an area for trace metals

The metal contents of pollen loads gathered by honeybees have been determined in areas with known concentrations of soil-borne heavy metals. The manganese, zinc, copper, and lead contents of the pollen loads reflected those of the environment, indicating that honeybee colonies might be used to sample areas.     

Book reviews

Local Planning in the Netherlands and England

J. Minett

Working Paper No. 37, Oxford Polytechnic, Department of Town and Country Planning, May 1979, 98 p.p.     

Inactivation of Cryptosporidium by ozone and cell ultrastructures

The fluorescence staining method and scanning electron microscopy (SEM) were used to study the effect of ozone (O3) inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily.Results indicated that O3 had a stronger inactivating capability.When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min,a significant inactivating effect could be achieved.The turbidity on inactivation effects was also found to be statistically significant in artificial water.With increases in turbidity,the inactivating effect decreased.Inactivation rate improved with a temperature increase from 5 to 25°C,but decreased beyond this.The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions.When the concentration of organic matter in the reaction system was increased,the competition between Cryptosporidium and organics with O3 probably took place,thereby reducing the inactivation rate.In addition,the cellular morphology of Cryptosporidium varied with different contact times.At zero contact time,cells were rotundity and sphericity,at 60 sec they became folded,underwent emboly,and burst at 480 sec,the cell membrane of Cryptosporidium shrinked and collapsed completely.