Grassroots “flexible specialisation” in Brisbane’s West End: towards a politics of economic possibility

The focus on ‘flexible specialisation’ in the 1980s and 1990s marked an important turning point in framings of economic agency and diversity within economic geography. This article deconstructs the ways in which subjects were framed as ‘flexible’ in both the flexible specialisation literature and later work on the Diverse Economy (Gibson-Graham 1996, 2002, 2006), seeking out particular examples of the ways in which different projects of subjection appear to frame different views of economic possibility. Drawing richly on a case study of residents in an inner-city neighbourhood of West End, Brisbane (Australia), this paper uses resident’s articulations of their everyday practices to reinvigorate some of the ideas of the flexible specialisation literature and challenge, defamiliarise and rework existing ideas of economic life in “First World”, urban contexts.     

A new procedure for separating and measuring radiogenic isotopes (U, Th, Pa, Ra, Sr, Nd, Hf) in ice cores

A new method for the radiogenic isotope (U–Th–Pa–Ra, Sr, Nd, Hf) analysis of the soluble and insoluble components found within ice cores is presented. Melting experiments with rock standards in the presence of EDTA indicate that carbonates, as well as silicates, can be buffered sufficiently to preclude dissolution. The use of EDTA allows adsorbing species, such as Th and Hf, to remain in solution during melting thus fully separating the dust (insoluble) and sea salt (soluble) components of the ice after filtration. A new elemental separation scheme for low sample masses, less than 5 mg solid material, utilizes 4 primary ion exchange columns and two “clean-up” columns to fully isolate U, Th, Pa, Ra, Sr, Nd, and Hf while maintaining high yields. Elution schemes measured for USGS rock standards and a Chinese loess are presented to provide a comparison for variable matrix compositions. Mass spectrometer techniques were modified to measure small aliquots of the standards, equivalent to the amounts found in ice core samples, 10 ng and less. A MC-ICPMS was employed for the measurement of U, Th, Pa, Ra, and Hf; results of the experiments show that with ion yields up to 1%, rock standards have errors for ²³⁴U/²³⁸U of 1%, ²³⁰Th/²³²Th of 1.5%, [²²⁸Ra] of 9%, and ¹⁷⁶Hf/¹⁷⁷Hf of 100 ppm. MC-TIMS measurements of Sr and Nd show similar errors for small sample sizes: ⁸⁷Sr/⁸⁶Sr of 50 ppm and ¹⁴³Nd/¹⁴⁴Nd of 80 ppm. This new analytical method increases the number of possible tracers measured from a single sample, reducing separation times and sample consumption, as well as providing the addition of a radiometric clock, U-series, to the traditional suite of isotopic tracers, Sr, Nd, and Hf.     

Recent progress on combining geomorphological and geochronological data with ice sheet modelling,demonstrated using the last British–Irish Ice Sheet

Palaeo-ice sheets are important analogues for understanding contemporary ice sheets, offering a record of ice sheet behaviour that spans millennia. There are two main approaches to reconstructing palaeo-ice sheets. Empirical reconstructions use the available glacial geological and chronological evidence to estimate ice sheet extent and dynamics but lack direct consideration of ice physics. In contrast, numerically modelled simulations implement ice physics, but often lack direct quantitative comparison with empirical evidence. Despite being long identified as a fruitful scientific endeavour, few ice sheet reconstructions attempt to reconcile the empirical and model-based approaches. To achieve this goal, model-data comparison procedures are required. Here, we compare three numerically modelled simulations of the former British–Irish Ice Sheet with the following lines of evidence: (a) position and shape of former margin positions, recorded by moraines; (b) former ice-flow direction and flow-switching, recorded by flowsets of subglacial bedforms; and (c) the timing of ice-free conditions, recorded by geochronological data. These model–data comparisons provide a useful framework for quantifying the degree of fit between numerical model simulations and empirical constraints. Such tools are vital for reconciling numerical modelling and empirical evidence, the combination of which will lead to more robust palaeo-ice sheet reconstructions with greater explicative and ultimately predictive power.     

A scoping review on the multiplicity of scale in spatial analysis

Journal of Geographical Systems - Scale is a central concept in the geographical sciences and is an intrinsic property of many spatial systems. It also serves as an essential thread in the fabric...     

Student Learning in an Introductory GIS Course: Using a Project‐Based Approach

Introductory courses in Geographic Information Science (GIS) expose students to the concepts and practices necessary for future academic and professional use of GIS tools. Traditional GIS courses balance lectures in the theories of GIS with pre‐built and pre‐packaged lab activities to learn the practices of GIS. This article presents a case study of an experimental introductory course in which students conducted novel, independent project‐based group research under the supervision of graduate or advanced undergraduate students enrolled in the course, culminating in a class presentation and publication quality paper. Surveys and interviews indicated that students reacted more positively to project‐based group research than to traditional activities. Students felt the projects better prepared them for ‘real world’ applications of GIS, and recommend project‐based group research in other GIS coursework. Additionally, our findings indicate that students appreciate interactions with peers of varying skill levels and experiences, as these broaden their capabilities to work with other GIS users.     

The soil hydrologic response to forest regrowth: a case study from southwestern Amazonia

As a large and dynamic land‐use category, tropical secondary forests may affect climate, soils, and hydrology in a manner different from primary forests or agricultural areas. We investigated the saturated hydraulic conductivity K_sat of a Kandiudult under different land uses in Rondonia, Brazil. We measured K_sat at four depths (12·5, 20, 30 and 50 cm) under (a) primary forest, (b) a former banana–cacao plantation (SF1), and (c) an abandoned pasture (SF2). At 12·5 cm, all three land uses differ significantly (α = 0·1), but not at the 20 and 30 cm depths. At 50 cm, K_sat was significantly greater in the former pasture than in other land uses. Lateral subsurface flow is expected during intense rainfall (about 30 times per year) at 30 cm depth in SF1 and at 50 cm depth in the forest, whereas the relatively low permeability at shallow 12·5 cm in the SF2 may result not only in lateral subsurface flow, but also saturation overland flow. For modelling purposes, recovering systems seem to have K_sat values distinct from primary forest at shallow depths, whereas at deeper layers (>20 cm) they may be considered similar to forests. Copyright © 2002 John Wiley & Sons, Ltd.     

Reactive transport modeling of the role of fluorine-rich groundwater in the formation of fluorite ore deposits in the Illinois-Kentucky district,USA

Hydrogeology Journal - The Illinois-Kentucky ore district hosts the largest deposits of fluorite in the USA. A long-standing hypothesis for the formation of the Illinois-Kentucky deposits is that...     

Stable inversions for complete moment tensors

The seismic moment tensors for certain types of sources, such as volcanic earthquakes and nuclear explosions are expected to contain an isotropic component. Some earlier efforts to calculate the isotropic component of these sources are flawed due to an error in the method of Jost & Herrmann. We corrected the method after Herrmann & Hutchensen and found great improvement in the recovery of non-double-couple moment tensors that include an isotropic component. Tests with synthetic data demonstrate the stability of the corrected linear inversion method, and we recalculate the moment tensor solutions reported in Dreger et al. for Long Valley caldera events and Dreger & Woods for Nevada Test Site nuclear explosions. We confirm the findings of Dreger et al. that the Long Valley volcanic sources contain large statistically significant isotropic components. The nuclear explosions have strikingly anomalous source mechanisms, which contain very large isotropic components, making it evident that these events are not tectonic in origin. This indicates that moment tensor inversions could be an important tool for nuclear monitoring.     

Relative sea‐level observations in western Scotland since the Last Glacial Maximum for testing models of glacial isostatic land movements and ice‐sheet reconstructions

Observations of relative sea‐level change and local deglaciation in western Scotland provide critical constraints for modelling glacio‐isostatic rebound in northern Britain over the last 18 000 years. The longest records come from Skye, Arisaig and Knapdale with a shorter, Holocene, record from Kintail. Biostratigraphic (diatom, pollen, dinoflagellate, foraminifera and thecamoebian), lithological and radiocarbon analyses provide age and elevation parameters for each sea‐level index point. All four sites reveal relative sea‐level change that is highly non‐monotonic in time as the local vertical component of glacio‐isostatic rebound and eustasy (or global meltwater influx) dominate at different periods. Copyright © 2006 John Wiley & Sons, Ltd.