Ground-breaking: Scientific and sonic perceptions of environmental change in the African Sahel

Soils surrounding ancient settlements can hold evidence of the activities of past societies. To seek an understanding of how past societies have reacted and contributed to environmental change requires many data sources. The real-time audiovisual installation Ground-breaking problematises the presentation of such data gained through the image-analysis of soil materials. These data are used to connote environmental events and consequent human responses. Combining these data with audiovisual synthesis and environmental recordings, a basis for developing conceptualizations of new locales undergoing environmental change is presented; the visual and sonic narratives developed allowing the art-science interface to be explored

A Reduction in Serum Cytokine Levels Parallels Healing of Venous Ulcers in Patients Undergoing Compression Therapy

AbstractIntroduction vascular endothelial growth factor (VEGF) and tumour necrosis factor alpha (TNFα) have been specifically implicated in the tissue damage associated with chronic venous disease (CVD). Furthermore, production of both factors is known to be upregulated in vessel wall cells subject to hypertension. The aim of this study was to determine the local venous levels of VEGF and TNFα in limbs with venous ulcers before and after treatment with graduated compression. Patients and methods eight patients with venous ulcers and 8 patients with varicose veins only were included in the study. For ulcer patients, serum samples were taken from the superficial veins in lower limbs and repeated after 4 weeks of treatment with 4-layered graduated compression. Serum from the arms of the same patients served as controls. Determination of the concentrations of VEGF and TNFα proteins were performed with sandwich enzyme-linked immunosorbent assays. Results both groups of patients had elevated levels of VEGF and TNFα. In patients with venous ulcers there was a reduction in the levels of both cytokines to below control values with treatment. These changes correlated with healing of the ulcers as determined by reduction in ulcer size. Conclusion these data, for the first time, suggest a central role for both TNFα and VEGF in the pathogenesis of venous ulceration which may constitute a causative link between venous hypertension and tissue pathology

Are biological systems poised at criticality?

Many of life's most fascinating phenomena emerge from interactions among many elements--many amino acids determine the structure of a single protein, many genes determine the fate of a cell, many neurons are involved in shaping our thoughts and memories. Physicists have long hoped that these collective behaviors could be described using the ideas and methods of statistical mechanics. In the past few years, new, larger scale experiments have made it possible to construct statistical mechanics models of biological systems directly from real data. We review the surprising successes of this "inverse" approach, using examples form families of proteins, networks of neurons, and flocks of birds. Remarkably, in all these cases the models that emerge from the data are poised at a very special point in their parameter space--a critical point. This suggests there may be some deeper theoretical principle behind the behavior of these diverse systems.Comment: 21 page

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

FIRST SEARCHES FOR OPTICAL COUNTERPARTS TO GRAVITATIONAL-WAVE CANDIDATE EVENTS

During the LIGO and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

Study of mechanical behavior and internal structure of ferritic nanocrystalline material

The research thrust of this grant has been directed into two areas. The principal effort has been spent in an investigation of the synthesis, mechanical behavior and internal structure of ferritic nanocrystalline material. A second effort involves a study of the high temperature behavior of several ferritic steels. In particular, we are investigating the precursors and earliest stages of fatigue crack initiation, especially how initiation is affected by hold times and by environment