Similarities and differences in the historical records of lava dome-building volcanoes: implications for understanding magmatic processes and eruption forecasting

A key question for volcanic hazard assessment is the extent to which information can be exchanged between volcanoes. This question is particularly pertinent to hazard forecasting for dome-building volcanoes, where effusive activity may persist for years to decades, and may be punctuated by periods of repose, and sudden explosive activity. Here we review historical eruptive activity of fifteen lava dome-building volcanoes over the past two centuries, with the goal of creating a hierarchy of exchangeable (i.e., similar) behaviours. Eruptive behaviour is classified using empirical observations that include patterns of SO2 flux, eruption style, and magma composition. We identify two eruptive regimes: (i) an episodic regime where eruptions are much shorter than intervening periods of repose, and degassing is temporally correlated with lava effusion; and (ii) a persistent regime where eruptions are comparable in length to periods of repose and gas emissions do not correlate with eruption rates. A corollary to these two eruptive regimes is that there are also two different types of repose: (i) inter-eruptive repose separates episodic eruptions, and is characterised by negligible gas emissions and (ii) intra-eruptive repose is observed in persistently active volcanoes, and is characterised by continuous gas emissions. We suggest that these different patterns of can be used to infer vertical connectivity within mush-dominated magmatic systems. We also note that our recognition of two different types of repose raises questions about traditional definitions of historical volcanism as a point process. This is important, because the ontology of eruptive activity (that is, the definition of volcanic activity in time) influences both analysis of volcanic data and, by extension, interpretations of magmatic processes. Our analysis suggests that one identifying exchangeable traits or behaviours provides a starting point for developing robust ontologies of volcanic activity. Moreover, by linking eruptive regimes to conceptual models of magmatic processes, we illustrate a path towards developing a conceptual framework not only for comparing data between different volcanoes but also for improving forecasts of eruptive activity

A negative autoregulatory link between Nramp1 function and expression

Nramp1 (natural resistance-associated macrophage protein) controls resistance to infection by intracellular pathogens in mice. Nramp1 regulates the microenvironment of the invading pathogen by increasing the luminal iron that participates in the Haber-Weiss reaction, producing radicals that attack the pathogen. We have studied the effect of inflammatory stimuli, iron, and sodium nitroprusside on Nramp1 expression in bone marrow macrophages. Investigations show all three up-regulate Nramp1 expression with a parallel increase in immunoreactivity to an amino-terminal antibody and Nramp1 mRNA. Growth rates are reduced in macrophage cell lines expressing Nramp1. This is through a decrease in iron availability, shown by an increase in IRP2 activity and a reciprocal decrease in conventional protein kinase Cbeta-1 expression. We propose that Nramp1 activity may control its own expression via a negative autoregulatory loop that is important for iron homeostasis and maintenance of low cytoplasmic redox active iron levels in the macrophage

Risk: the ethics of a creative curriculum

Regulations in Higher Education, e.g. subject benchmarks, the qualifications framework (QAA) and the CATs system. play an important role in ensuring the quality of educational standards. They assure students that each CAT point they acquire has value and that ‘graduateness’ is of equal worth regardless of location or subject. In addition, a growing consumer ethos and the introduction of fees encourage students and their financial supporters to view Higher Education as a product. Whilst the student’s own motivation and input is still important, Universities are expected to deliver learning opportunities that maximise the likelihood of successful completion. Innovation and creativity do not sit comfortably within this paradigm. Delivering educational experiences where the outcome is uncertain, or where there are less clear and objective methods for measuring student achievement, presents a risk to educational standards and to student experience. This paper seeks to explore the relationship between risk, ethics and the introduction of creativity and innovation into the curriculum. It is generally accepted that university education should be challenging – encouraging the development of an enquiring mind that does not accept things at face value and the confidence to argue from an alterative viewpoint. These aspirations are related to notions of autonomy as espoused by J S Mill (1859) and others. Nurturing such attributes means respecting the autonomy of the student to make decisions, stand by them and to take responsibility for risk taking and its outcomes. It also means allowing lecturers to design courses that permit change, diversity of practice and risk taking. By contrast an unintended effect of the paradigm outlined above is a culture in which individual academic freedom is stifled by the need for conformity. Success may be measured by the averagely intelligent student, with average levels of motivation, achieving an award one point higher on the value added scale than they came with. The ethical principle of non-maleficence takes precedence such that the possibility of doing harm – to the student or University - outlaws risk taking behaviour in curriculum design and delivery. Utilitarian ethics (West 2004) is effective in surfacing such dilemmas. Its use in detailed analysis may help students and academics to plot the risks and benefits of innovative practice

c-Myc represses the murine Nramp I promoter

The Nramp1 (natural resistance-associated macrophage protein 1) gene modulates the growth of intracellular pathogens and encodes a divalent cation transporter within lysosomes/late endosomes of macrophages. Nramp1 modulates the cytoplasmic iron pool. Wu, Polack and Dalla-Favera [(1999) Science 283, 676–679] showed reciprocal control of H-ferritin and IRP2 by c-Myc, and suggest that c-Myc regulates genes to increase cytoplasmic iron. A role for c-Myc in Nramp1 regulation was evaluated. Co-transfection studies show that c-Myc represses Nramp1 promoter function. Five non-canonical Myc-max binding sites (E-box) identified within the Nramp1 5´-flanking sequence are not responsible for the inhibitory effects of c-Myc on Nramp1 expression. An initiator(s) adjacent to the transcription-initiation site is a candidate for the inhibition observed. Results are consistent with a role for Nramp1 removing iron from the cytosol and antagonizing c-Myc function

Britain's undefended frontier A policy for Ulster; the report of an independent study group

3.50Available from British Library Lending Division - LD:3829.97035(2) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Perceptions of the learning environment, learning preferences, and approaches to studying among medical students in Pakistan

Students at a Pakistani medical college were surveyed using instruments taken from Western research. The students who rated their courses positively tended to adopt an organised approach in their learning and studying. The students who perceived that their assessment and workload were inappropriate preferred a transmissive approach to teaching and adopted a surface approach in their learning and studying. The students who preferred a student-centred approach to teaching tended to adopt a deep approach in their learning and studying. This confirms the idea, well established in Western research, that there exists a strong relationship between students’ perceptions of their courses and the approaches that they adopt on those courses. However, the incorporation of problem-based learning in the medical curriculum had not led to any enhancement of their perceptions and preferences, nor had it led to an unambiguous improvement in their approaches to studying. This is attributed to the hybrid nature of their programmes, in which problem-based activities were combined with more conventional forms of teaching and assessment, and to the anxiety and stress which seem to be common among students at medical schools in Pakistan