Exploring the potential linkages between oil‐field brine reinjection,crystalline basement permeability,and triggered seismicity for the Dagger Draw Oil field,southeastern New Mexico,USA, using hydrologic modeling

We used hydrologic models to explore the potential linkages between oil‐field brine reinjection and increases in earthquake frequency (up to M_d 3.26) in southeastern New Mexico and to assess different injection management scenarios aimed at reducing the risk of triggered seismicity. Our analysis focuses on saline water reinjection into the basal Ellenburger Group beneath the Dagger Draw Oil field, Permian Basin. Increased seismic frequency (>M_d 2) began in 2001, 5 years after peak injection, at an average depth of 11 km within the basement 15 km to the west of the reinjection wells. We considered several scenarios including assigning an effective or bulk permeability value to the crystalline basement, including a conductive fault zone surrounded by tighter crystalline basement rocks, and allowing permeability to decay with depth. We initially adopted a 7 m (0.07 MPa) head increase as the threshold for triggered seismicity. Only two scenarios produced excess heads of 7m five years after peak injection. In the first, a hydraulic diffusivity of 0.1 m² s^?1 was assigned to the crystalline basement. In the second, a hydraulic diffusivity of 0.3 m² s^?1 was assigned to a conductive fault zone. If we had considered a wider range of threshold excess heads to be between 1 and 60 m, then the range of acceptable hydraulic diffusivities would have increased (between 0.1–0.01 m² s^?1 and 1–0.1 m² s^?1 for the bulk and fault zone scenarios, respectively). A permeability–depth decay model would have also satisfied the 5‐year time lag criterion. We also tested several injection management scenarios including redistributing injection volumes between various wells and lowering the total volume of injected fluids. Scenarios that reduced computed excess heads by over 50% within the crystalline basement resulted from reducing the total volume of reinjected fluids by a factor of 2 or more.     

From here to eternity?: The practice of knowledge transfer in dispersed and co-located project organizations

This paper extends theoretical and empirical debates on knowledge transfer practices in geographically dispersed project teams using a range of communications media. It presents quantitative data comparing work interactions between dispersed and co-located teams in five international, project-based firms. It shows that contrary to conventional wisdom, their respective practices are similar for many work activities such as search and routine information exchange. However dispersed team members validate, verify and consult differently to the respective co-located teams. Qualitative data from interviews and observation then illustrates typical interactions using the differing means and media available to the observed project teams, such as task decomposition and emergency corrective work. Due to an unfortunate oversight one of the references in this article is incomplete. It can be found here.     

Consuming Ethics: Articulating the Subjects and Spaces of Ethical Consumption

Geography's debates about how to maintain a sense of morally responsible action often emphasise the problematic nature of caring at a distance, and take for granted particular kinds of moral selfhood in which responsibility is bound into notions of human agency that emphasise knowledge and recognition. Taking commodity consumption as a field in which the ethics, morality, and politics of responsibility has been problematised, we argue that existing research on consumption fails to register the full complexity of the practices, motivations and mechanisms through which the working-up of moral selves is undertaken in relation to consumption practices. Rather than assuming that ethical decision‐making works through the rational calculation of obligations, we conceptualise the emergence of ethical consumption as ways in which everyday practical moral dispositions are re‐articulated by policies, campaigns and practices that enlist ordinary people into broader projects of social change. Ethical consumption, then, involves both a governing of consumption and a governing of the consuming self. Using the example of Traidcraft , we present a detailed examination of one particular context in which self‐consciously ethical consumption is mediated, suggesting that ethical consumption can be understood as opening up ethical and political considerations in new combinations. We therefore argue for the importance of the growth of ethical consumption as a new terrain of political action, while also emphasising the grounds upon which ethical consumption can be opened up to normative critique.     

FINGERPRINTING OF ROMAN MINTS USING LASER‐ABLATION MC–ICP–MS LEAD ISOTOPE ANALYSIS*

In this paper we present data to demonstrate the applicability of laser‐ablation MC–ICP–MS isotope analysis to archaeological artefacts, in this case Roman silver coins. The technique requires no chemical preparation, does minimal damage to the sample and yields external reproducibility that is better than conventional TIMS analysis; ²⁰⁷Pb/²⁰⁶Pb =±0.015% 2σ in comparison with ²⁰⁷Pb/²⁰⁶Pb =±0.04% 2σ, respectively. We show that Pb isotope compositions give isotope fingerprints to mints despite the likely reworking of the metal during coin production.     

From 'industrial districts' to 'knowledge clusters': a model of knowledge dissemination and competitive advantage in industrial agglomerations

This paper integrates knowledge-based theories of the firm withgeograph-ical studies of industrial agglomeration to producea model that helps explain the competitive advantages enjoyedby proximate firms located in geographical clusters. We proposea hierarchy of specialized knowledge stocks at both firm andcluster levels and suggest that the comparative advantage conferredby knowledge resources at each level is protected, in part,by asymmetries in knowledge flows from level to level. The paperargues that codified component knowledge is more easily spreadthan firm-specific architectural knowledge. Nevertheless, overtime, agglomerations may develop a cluster-specific form ofarchitectural knowledge that facilitates the rapid disseminationof knowledge throughout the cluster by increasing the learningcapacity of proximate firms and thereby conferring cluster-specificcompetitive advantages.     

Oxygen and strontium isotope evidence for mobility in Roman Winchester

Artefacts and burial rites in the late Roman cemetery at Lankhills School, Winchester, southern England, were used by Clarke (1979) to distinguish between local Romano-British individuals and migrants thought to be from the Danube region, a suggestion tested through isotope analysis by Evans et al. (2006a,b). This paper reports strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (δ¹⁸O) isotope data for tooth enamel sampled from a further 40 individuals from more recent excavations on the same site. Results suggest that up to a quarter of the sampled Lankhills individuals were incomers, with several individuals possibly originating from the Hungarian Basin and the Southern Mediterranean. However, there was no clear link between isotopic signature and archaeological origin attribution, suggesting that in many cases burial practice was dictated by factors other than ‘ethnicity’, such as kinship, marriage or cultural and political preferences.     

Currents and trends in the archaeological sciences

Here I use ISI Web of Knowledge to build on a recent paper by Butzer (2009) and track current trends in the archaeological sciences. I researched eight thematic keywords replete in the title, abstract, keywords and main body of archaeological science literature for the period 1970–2008. For all keywords investigated a steady rise in archaeological science research is evidenced after 1980, with pronounced growth occurring after 2000. I attribute this pattern to the standardisation of research production and academic evaluation, in addition to the democratisation of new information technologies, notably the Internet. The evolution of 10 leading archaeological science journals was also tracked. Since the 1970s, the bibliometric data show that nine of the ten journals have successfully expanded on an annual basis. I found that the biggest growers (the Journal of Archaeological Science [JAS], the Journal of Human Evolution and the Journal of Anthropological Archaeology) are all published by Elsevier. In 2008, the JAS was ranked first for five of the eight thematic keywords by ISI, underlining the popularity and interdisciplinary scope of the journal. According to the 2008 Journal Citation Reports, the JAS ranks second for total citations (4219) in archaeological science and third for its overall impact factor (1.779).     

pXRF: a study of inter-instrument performance

Integrating portable X-ray fluorescence (pXRF) instrumentation into archaeological investigations has generated as much interest as skepticism because several characteristics of the technique limit analytical accuracy and precision. This paper seeks to explore inter-instrument performance in order to assess the potential pXRF instrumentation has in examining the elemental composition of lithic raw materials. Two pXRF instruments, Delta and Omega models both manufactured by Olympus Innov-X Systems, were utilized to obtain the trace element signatures of five fine-grained volcanic sources and four obsidian sources in the Great Basin. We compared the two portable instruments to a wavelength-dispersive instrument extensively calibrated with geologic standards and to a commercial benchtop energy-dispersive system. Our results suggest that the relationships between the data produced by these different instruments are complex, and as we look to the future of pXRF use in archaeological analysis we argue that that the same strict protocols applied in laboratory-based XRF analyses, involving instrument calibration, evaluation of inter-instrument performance, and comparison to accepted geologic standards, need to be applied in pXRF analysis.     

Reaping the rewards: the potential of well designed methodology,a comment on Vardi et al. (Journal of Archaeological Science 37 (2010) 1716–1724) and Goodale et al. (Journal of Archaeological Science 37 (2010) 1192–1201)

The recent articles by Vardi et al., “Tracing sickle blade levels of wear and discard patterns: a new sickle gloss quantification method” (Journal of Archaeological Science 37 (2010) 1716–1724), and Goodale et al., “Sickle blade life-history and the transition to agriculture: an early Neolithic case study from Southwest Asia” (Journal of Archaeological Science 37 (2010) 1192–1201), are two papers that seek to address interesting archaeological questions through the development of new approaches to measuring the duration of stone tool use. Here comment is made on the fashion in which research design and analytic procedures contribute to limit the capabilities of each of the techniques presented. Whilst the authors support the investigation of novel techniques, in order for the results of any use-wear analysis to be accepted as reliable the methods employed must be demonstrably sound.