Optical and near-infrared colours as a discriminant of the age and metallicity of stellar populations

We present a comprehensive analysis of the ability of current stellar population models to reproduce the optical ( ugriz ) and near-infrared ( JHK ) colours of a small sample of well-studied nearby elliptical and S0 galaxies. We find broad agreement between the ages and metallicities derived using different population models, although different models show different systematic deviations from the measured broad-band fluxes. Although it is possible to constrain simple stellar population models to a well-defined area in age–metallicity space, there is a clear degeneracy between these parameters even with such a full range of precise colours. The precision to which age and metallicity can be determined independently, using only broad-band photometry with realistic errors, is  Δ[Fe/H]≃ 0.18  and  Δlog Age ≃ 0.25  . To constrain the populations and therefore the star formation history further, it will be necessary to combine broad-band optical–IR photometry with either spectral line indices, or else photometry at wavelengths outside this range.     

Local Governance for Social Sustainability: equity as a strategic response to neoliberal constraints in food security initiatives

Scholarly literature recognises the importance of social sustainability as part of the wider sustainability agenda. A wide array of concepts such as equity, social justice, democratic government, social inclusion, social capital and quality of life are thought to constitute social sustainability. Local governments are charged with delivering social programs and services to their constituency, but market logics and performance-based institutional cultures, along with limited authority and funding, constrain their capacity to respond to new initiatives. We analyse two case studies in Victoria, Australia, to explore how elements of social sustainability are articulated and operationalised within local government. Each case study involved State-level and local government partnerships in health-promotion initiatives to improve food security. Analysis was conducted on 50 primary policy documents, 22 secondary data documents and 27 interviews. Findings reveal that a systems-based or integrated approach to social sustainability was not workable but not completely ineffective. Equity was prioritised by local government in both case studies, and well acknowledged as interconnected with other social goals. Although constrained in its capacity to deliver new initiatives, local government responded to neoliberalising ideologies, as well as its constituency, by strategically focusing on a particular goal, such as equity.     

A sea bottom multichannel hydrophone array

The PUMA (Pull-Up Multichannel Array) is a sea-bottom instrument for remotely recording data from a 12 channel hydrophone array. Its purpose is to achieve (i) denser data coverage, leading to (ii) improved velocity analysis and (iii) multichannel processing of wide angle seismic data collected on the continental shelf. The instrument consists of a 1.2 km array terminating with a pressure case in which 8 FM cassette recorders, a power supply, microprocessor controller and internal clock are housed. It can be pre-programmed to switch on during shot windows for a total of four hours recording time.The PUMA was successfully used in an experiment west of Lewis, Outer Hebrides, U.K. in August–September 1984. We show an example of PUMA data from this experiment. Indications are that the instrument will provide improved constraints on seismic velocities in the lower continental crust and uppermost mantle.     

Deglacial to postglacial palaeoenvironments of the Celtic Sea: lacustrine conditions versus a continuous marine sequence

Recent work on the last glaciation of the British Isles has led to an improved understanding of the nature and timing of the retreat of the British?Irish Ice Sheet (BIIS) from its southern maximum (Isles of Scilly), northwards into the Celtic and Irish seas. However, the nature of the deglacial environments across the Celtic Sea shelf, the extent of subaerial exposure and the existence (or otherwise) of a contiguous terrestrial linkage between Britain and Ireland following ice retreat remains ambiguous. Multiproxy research, based on analysis of 12 BGS vibrocores from the Celtic Deep Basin (CDB), seeks to address these issues. CDB cores exhibit a shell‐rich upward fining sequence of Holocene marine sand above an erosional contact cut in laminated muds with infrequent lonestones. Molluscs, in situ Foraminifera and marine diatoms are absent from the basal muds, but rare damaged freshwater diatoms and foraminiferal linings occur. Dinoflagellate cysts and other non‐pollen palynomorphs evidence diverse, environmentally incompatible floras with temperate, boreal and Arctic glaciomarine taxa co‐occurring. Such multiproxy records can be interpreted as representing a retreating ice margin, with reworking of marine sediments into a lacustrine basin. Equally, the same record may be interpreted as recording similar conditions within a semi‐enclosed marine embayment dominated by meltwater export and deposition of reworked microfossils. As assemblages from these cores contrast markedly with proven glaciomarine sequences from outside the CDB, a glaciolacustrine interpretation is favoured for the laminated sequence, truncated by a Late Weichselian transgressive sequence fining upwards into fully marine conditions. Reworked rare intertidal molluscs from immediately above the regional unconformity provide a minimum date c. 13.9 cal. ka BP for commencement of widespread marine erosion. Although suggestive of glaciolacustrine conditions, the exact nature and timing of laminated sediment deposition within the CDB, and the implications this has on (pen)insularity of Ireland following deglaciation, remain elusive.     

A Bayesian statistical assessment of representative samples for asteroidal or meteoritical material

Primitive substances in asteroid and meteorite materials represent a record of early solar system evolution. To allow the study of these materials, they must be collected and transferred to the laboratory. Collection during sample return missions requires an assessment of the size of samples needed. Meteorite falls or finds must be subdivided into appropriate subsamples for analysis by successive generations of scientists. It is essential, therefore, to determine a representative mass or volume at which the collected or allocated sample is representative of the whole. For the first time, we have used a Bayesian statistical approach and a selected meteorite sample, Murchison, to identify a recommended smallest sample mass that can be used without interferences from sampling bias. Enhancing background knowledge to inform sample selection and analysis is an effective means of increasing the probability of obtaining a positive scientific outcome. The influence of the subdivision mechanism when preparing samples for distribution has also been examined. Assuming a similar size distribution of fragments to that of the Murchison meteorite, cubes can be similarly representative as fragments, but at orders of magnitude smaller sizes. We find that: (1) at all defined probabilities (90%, 95%, and 99%), nanometer‐sized particles (where the axes of a three‐dimensional sample are less that a nanometer in length) are never representative of the whole; (2) at the intermediate and highest defined probabilities (95% and 99%), micrometer‐sized particles are never representative of the whole; and (3) for micrometer‐sized samples, the only sample that is representative of the whole is a cube and then only at a 90% probability. The difference between cubes and fragments becomes less important as sample size increases and any >0.5 mm‐sized sample will be representative of the whole with a probability of 99.9%. The results provide guidance for sample return mission planners and curators or advisory boards that must distribute valuable samples for analysis.     

The application of geodetic radio interferometric surveying to the monitoring of sea-level

Summary. Under project IRIS (International Radio Interferometric Surveying) geodesists are using Very Long Baseline Interferometry (VLBI) to monitor polar motion to 1-2 ms of arc and UT1 to 0.05-0.10 ms, and to develop a global geodynamic network to detect and study centimetre level displacements of reference points associated with large-scale phenomena such as tectonic plate motion and glacial rebound. Differential positioning techniques using the signals broadcast by the satellites of the Global Positioning System (GPS) are being used to study finer scale phenomena, such as localized subsidence, and economically to relate these specialized surveys to the geodynamic network. Including tide gauge stations in this system will make it possible to detect motions of specific gauges and correct or delete the measurements from those gauges when computing changes in sea-level. The National Oceanic and Atmospheric Administration (NOAA) has selected several tide gauges on the east and west coasts of the United States, and initial epoch GPS surveys to tie the gauges to VLBI observations have already begun. Other countries participating in project IRIS are planning similar activities. In addition to providing a globally based land reference datum for the tide gauge measurements, the IRIS polar motion and UT1 time series may contribute directly to monitoring and interpreting global sea level changes. Changes in the volume and distribution of ice masses result in long-term motions of the axis of rotation, and sea-level changes affect the length of day (lod). The IRIS time series will certainly have the resolution required to detect the expected polar motion and changes in lod, and a properly designed global VLBI/GPS network should allow the ice/sea-level effects to be separated from crustal dynamics effects.     

Numerical simulation of a random sea: a common error and its effect upon wave group statistics

A commonly used method of simulating ocean waves from a specified frequency spectrum is shown to be incorrect. The method consists of adding numerous sine curves with random phases; and the error arises from assuming that the amplitudes of these component sine waves are deterministic, when they are in fact random variables. Methods of using random amplitudes are described and only one is found to be satisfactory. In this method the number of random values simulated — and then transformed with an inverse FFT — equals the required number of simulated data points. So simulation in the frequency domain can only give relatively short runs; it is necessary to work in the time domain if arbitrarily long runs are required.Errors in wave group statistics derived from the incorrect simulation method are discussed and related to discrepancies reported between groupiness in simulated data and ocean measurements.     

The precambrian of north-western Queensland,Australia

Precambrian rocks, ranging in age from probable Archaean to Upper Proterozoic, crop out over an area of 25,000 square miles in north-western Queensland. They fall into four large divisions, separated by major unconformities. Little is known of the history of the Archaean rocks, which are believed to include altered acid lavas, schists, gneisses and migmatite. The Lower Proterozoic strata form part of an orogenic belt. The Lower Proterozoic lower sequence is rich in altered acid and basic lavas. It has a maximum thickness of not less than 40,000 feet and was strongly deformed by east-west pressure and probably intruded by granite before the Lower Proterozoic upper sequence was deposited. Sediments form the bulk of the Lower Proterozoic upper sequence; these accumulated most thickly to the west and north-west of the core of lower sequence belt, but overlie lower sequence strata. The greatest thickness of sediments is at least 40,000 feet. The sequence was deformed by a renewal of east-west compressive stresses, accompanied by granite emplacement. Folding is strong to moderate, but lacks well-defined linearity in the west of the outcrop area.Upper Proterozoic sediments and lavas accumulated mainly in the west and north-west of the region. They are gently to moderately folded on west to north-west axes.The Precambrian in north-western Queensland, excluding the Camooweal Dolomite, crops out over about 25,000 square miles. Systematic field work was started by joint teams of the Commonwealth Bureau of Mineral Resources and the Geological Survey of Queensland in 1950.Reconnaissance mapping of the region was completed in 1954 but check work and more detailed mapping of areas of economic interest are still in progress. Maps are being prepared at a scale of 1 inch to 4 miles (1: 253,440) and a report on the area is being written (Carter andBrooks, in preparation). The Camooweal Dolomite, of Upper Proterozoic or Lower Cambrian age, is not included. Its stratigraphic and palaeographic position is discussed byNoakes (1956).The reconstruction of the geological history of the region presented below is an interpretation of the data obtained. The evidence is not sufficiently complete to enable a unique interpretation to be made of all aspects of the region's history. In particular the history of granite intrusion has not yet been completely unravelled.Paper published by permission of the Secretary, Department of National Development.     

Ethnicity in Eastern Europe: Historical legacies and prospects for cohesion

Eastern Europe lacks cohesion partly arising from a history of ethnic tension. Ways are now being found to overcome historic conflicts over alternative political structures, as the enlargement of membership for European institutions requires greater equality of rights at the same time as support and security is extended. Thus while ethnicity, as a political, social and cultural entity, persists in Eastern Europe as an essential element at the local level, it is now being seen more positively as cultural diversity and thus more compatible with democracy and a positive asset to national well-being. Multi-ethnic states are proving to be viable and some of the most intractable inter-ethnic problems (linked with the Hungarian minorities) are being addressed constructively. Yet there are signs that the southern part of the region is being marginalised regarding foreign investment. Also there is unease that European values are not being embraced unconditionally in parts of the Balkans. Recent military intervention has created fresh problems, committing the West to continued economic and political support to strengthen its stance on democracy and minority rights. This revised version was published online in July 2006 with corrections to the Cover Date.