Polyculture of scallopChlamys farreri and kelpLaminaria japonica in Sungo Bay

Several polyculture models of scallopChlamys farreri and kelpLaminaria japonica currently employed in Sungo Bay and other parts of northern China are described in this paper. Economic benefits of different polyculture models are analysed based on the growth rate, culture density and market price. In addition, site selection, critical environmental conditions and polyculture problems are discussed in detail. This project was funded by the International Development and Research Centre (IDRC), Canada, and the National Committee of Science and Technology of China.     

Changing conflict resolution institutions in the Ethiopian pastoral commons: the role of armed confrontation in rule-making

Pastoralist access and use of common grazing resources in the Horn of Africa increasingly include armed confrontation over diminishing resources and reduced access. This comes about as traditional customary institutions (sets of rules) for commons management become compromised due to the presence of outside influences and actors which significantly change both resource availability, and conceptions about who is subject to traditional rules governing commons – particularly rules associated with exclusion. At the same time a combination of local knowledge regarding what happens to open access commons (degradation), a reluctance to give up control of commons and associated ways of life, and armed conflict as a viable alternative for exclusion rules, provide for combative situations and large costs. While a great deal of valuable work has been accomplished regarding the derivation of effective institutions to better manage commons, situations of armed conflict can seem particularly distant from effective rule-making, because few institutions can endure the stresses of armed conflict. Recent developments in Ethiopia however suggest an unexpected proximity between armed confrontation and the prospect for commons management rule-making. With examples from the Afar, Somali and Karamojong Cluster pastoralists, this paper examines the ingredients for rule-making in combative commons situations. Specific coincident forms of state recognition, donor flexibility, perceptions of the cost of conflict, and the local to international reaction to these, are examined for their utility and limitations in the provision of a facilitating context for institution derivation for commons management.     

Clay mineral weathering and contaminant dynamics in a caustic aqueous system: II. Mineral transformation and microscale partitioning

Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite (Il), vermiculite (Vm) and montmorillonite (Mt) that were subjected to weathering in a simulated high-level radioactive tank waste leachate (0.05 m Al_T, 2 m Na⁺, 1 m NO₃⁻, pH ∼14, Cs⁺ and Sr²⁺ present as co-contaminants). Time series (0 to 369 d) experiments were conducted at 298 K, with initial [Cs]₀ and [Sr]₀ concentrations from 10⁻⁵ to 10⁻ mol kg⁻. Incongruent clay dissolution resulted in an accumulation of secondary aluminosilicate precipitates identified as nitrate-sodalite, nitrate-cancrinite and zeolite X, by molecular spectroscopy and electron microscopy (XRD, IR, NMR, SEM-EDS and TEM-EDS). Contaminant fate was dependent on competing uptake to parent clays and weathering products. TEM-EDS results indicated that high Il affinity for Cs was due to adsorption at frayed edge sites. The Il system also comprised Sr-rich aluminous precipitates after 369 d reaction time. In Mt systems, Cs and Sr were co-precipitated into increasingly recalcitrant spheroidal precipitates over the course of the experiment, whereas contaminant association with montmorillonite platelets was less prevalent. In contrast, Cs and Sr were found in association with weathered Vm particles despite the formation of spheroidal aluminosilicate precipitates that were comparable to those formed from Mt dissolution.     

Stereo-Photogrammetric Mapping of Tooth Replicas Incorporating Texture

Commercial digital photogrammetric software has been applied to convergent stereoscopic photography of human tooth replicas prepared to exhibit optical texture resulting in successful generation of 3D coordinate data. Tooth replicas were imaged using a semi-metric 35 mm camera and f = 100 mm macro lens on extension bellows. Model precision was within acceptable limits of 12  μ m or better for manual target matching and 21  μ m or better for automatic image matching. Further improvement in optical texture is required to achieve automatic image matching precision comparable to that of manual target matching. Small errors in interior orientation parameters attributed to instability in the bellows as well as small errors in the relative orientation resulted in some systematic errors. The use of a fixed camera lens system is expected to reduce these errors. When combined with commercially available, moderately priced, digital SLR cameras this brings 3D model generation closer to everyday clinical dental practice.     

High-purity quartz mineralisation in kyanite quartzites,Norway

This study presents an evaluation of Norwegian kyanite quartzites from Gullsteinberget, Knøsberget, Kjeksberget, Sormbrua, Tverrådalen, Juovva?orrú and Nasafjellet as potential deposits of high-purity quartz (HPQ) for use as raw material for special applications in high-technology industries. Fine-grained quartz, which forms 70 to 85 vol.% of these rocks, generally contains less than 50 μg g^?1 (total sum) of the structurally incorporated trace elements B, Li, Al, Ge, Ti, Fe, Mn, K and P. The concentrations are in the same range as those found in HPQ products, which are being mined and produced in Norway and elsewhere. Quartz analyses were performed using laser ablation–inductively coupled plasma mass spectrometry. Complimentary whole-rock analyses and cathodoluminescence studies of quartz were carried out to reveal processes, which have led to the low trace-element concentrations in quartz. This discovery, together with a better knowledge of the processes leading to the formation of HPQ in kyanite quartzites, could lead to the recognition of a new global type of HPQ resource applicable for industrial use. However, the processing technology necessary to separate HPQ from kyanite quartzite economically has not been developed so far.     

Carbonate Assimilation at Merapi Volcano, Java, Indonesia: Insights from Crystal Isotope Stratigraphy

Recent basaltic andesite lavas from Merapi volcano contain abundant,complexly zoned, plagioclase phenocrysts, analysed here fortheir petrographic textures, major element composition and Srisotope composition. Anorthite (An) content in individual crystalscan vary by as much as 55 mol% (An_40–95) across internalresorption surfaces with a negative correlation between highAn mol% (>70), MgO wt% and FeO wt%. In situ Sr isotope analysesof zoned plagioclase phenocrysts show that the ⁸⁷Sr/⁸⁶Sr ratiosof individual zones range from 0·70568 to 0·70627.The upper end of this range is notably more radiogenic thanthe host basaltic andesite whole-rocks (< 0·70574).Crystal zones with the highest An content have the highest ⁸⁷Sr/⁸⁶Srvalues, requiring a source or melt with elevated radiogenicSr, rich in Ca and with lower Mg and Fe. Recent Merapi eruptiverocks contain abundant xenoliths, including metamorphosed volcanoclasticsediment and carbonate country rock (calc-silicate skarns) analysedhere for petrographic textures, mineralogy, major element compositionand Sr isotope composition. The xenoliths contain extremelycalcic plagioclase (up to An₁₀₀) and have whole-rock ⁸⁷Sr/⁸⁶Srratios of 0·70584 to 0·70786. The presence ofthese xenoliths and their mineralogy and geochemistry, coupledwith the ⁸⁷Sr/⁸⁶Sr ratios observed in different zones of individualphenocrysts, indicate that magma–crust interaction atMerapi is potentially more significant than previously thought,as numerous crystal cores in the phenocrysts appear to be inheritedfrom a metamorphosed sedimentary crustal source. This has potentiallysignificant consequences for geochemical mass-balance calculations,volatile saturation and flux and eruptive behaviour at Merapiand similar island arc volcanic systems elsewhere. KEY WORDS: assimilation; isotopes; Merapi; xenolith; calc-silicate     

Intradaily variability of water quality in a shallow tidal lagoon: Mechanisms and implications

Although surface water quality and its underlying processes vary over time scales ranging from seconds to decades, they have historically been studied at the lower (weekly to interannual) frequencies. The aim of this study was to investigate intradaily variability of three water quality parameters in a small freshwater tidal lagoon (Mildred Island, California). High frequency time series of specific conductivity, water temperature, and chlorophylla at two locations within the habitat were analyzed in conjunction with supporting hydrodynamic, meteorological, biological, and spatial mapping data. All three constituents exhibited large amplitude intradaily (e.g., semidiurnal tidal and diurnal) oscillations, and periodicity varied across constituents, space, and time. Like other tidal embayments, this habitat is influenced by several processes with distinct periodicities including physical controls, such as tides, solar radiation, and wind, and biological controls, such as photosynthesis, growth, and grazing. A scaling approach was developed to estimate individual process contributions to the observed variability. Scaling results were generally consistent with observations and together with detailed examination of time series and time derivatives, revealed specific mechanisms underlying the observed periodicities, including interactions between the tidal variability, heating, wind, and biology. The implications for monitoring were illustrated through subsampling of the data set. This exercise demonstrated how quantities needed by scientists and managers (e.g., mean or extreme concentrations) may be misrepresented by low frequency data and how short-duration high frequency measurements can aid in the design and interpretation of temporally coarser sampling programs. The dispersive export of chlorophylla from the habitat exhibited a fortnightly variability corresponding to the modulation of semidiurnal tidal currents with the diurnal cycle of phytoplankton variability, demonstrating how high frequency interactions can govern long-term trends. Process identification, as through the scaling analysis here, can help us anticipate changes in system behavior and adapt our own interactions with the system.     

Community transport, social capital and social exclusion in rural areas

The concept of social capital has been used by numerous authors to investigate various topics. As yet, however, little attention has been paid to its relationship with mobility and social exclusion. Those findings which have been published suggest that the maintenance of social capital and associated networks within and between communities largely depends on mobility, but that local social networks are being undermined as a result of growing car ownership and use. This paper draws on the results of recent rural transport research to suggest that, at the same time, strong local social capital appears important in conferring mobility on certain social groups, especially those without access to a car. In the context of community transport, our analysis uses a geographic framework to attempt to explore these positions and reviews arising policy and research implications.