Imidazoles present a tunable, versatile and economical platform for the development of novel liquid solvents and polymer membranes for CO2 capture. An overview of our studies in this area is presented, with emphasis on characterization of structure-property relationships in imidazole-based materials through both experimental and computational studies. To this end, a growing library of systematically varied imidazole compounds has been synthesized using only commercial available starting materials and straightforward reactions. Using this library of compounds, we have sought to understand and develop predictive models for thermophysical properties relating to process design, including: density, viscosity, vapor pressure, pKa and CO2 absorption capacity. Furthermore, we have discovered that imidazoles are stable in the presence of SO2 and can form reversible 1:1 adducts, which can be beneficial as SO2 is typically present at ppm levels alongside CO2 in flue gas from coal-fired power plants.

Quartz, the most common mineral on earth, is almost universally associated with shamans. Why this ritual association occurred worldwide has remained unexplained scientifically, at least in part because western scientific thinking assumes that religious beliefs and practices are epiphenomenal and not worthy of study. This association is archaeologi-cally evident at Sally's Rocksheiter, a small rock engraving-vision quest site in the Mojave Desert, where quartz rocks were placed as offerings in cracks around the rock art panel. SEM and electron microprobe foreign materials analyses of Mojave rock engravings show that the association between quartz and rock art was common: almost 65 per cent contained remnants of quartz hammerstones, used to peck the motifs. A combination of ethnohistory and physical sciences explains why quartz, shamans and vision questing were so strongly associated: triboluminescence causes quartz to glow when struck or abraded, which was believed a visible manifestation of supernatural power. Recognition that this belief and behavioural association were based on quartz's physical properties aids our ability to identify the antiquity of the vision quest in the far west, suggesting that Mojave Desert shamanism is the oldest continuously practiced religious tradition so far identified in the world.

Howey and O'Shea (2006) misrepresent one of my statements twice, attributing a position to me that I have argued against for two decades: they misrepresent the way that ethnography is used in the archaeology of religion and the manner in which rock art research is conducted; and, despite their claims to the contrary, their study illustrates the importance of the identification of meaning in the archaeology of religion.

Ethnographic data on the production of rock art in far western North America - the historic hunter-gatherer cultures of California and the Great Basin - are reviewed and analyzed to identify widespread patterns in the origin and, in certain cases, symbolism of the late prehistoric/historical parietal art of this region. These data, collected in the first few decades of this century by a variety of ethnographers, suggest only two origins for the art: production by shamans; and production by initiates in ritual cults. In both instances, the artists were apparently depicting the culturally-conditioned visions or hallucinations they experienced during altered states of consciousness. The symbolism of two sites, Tulare-19 and Ventura-195, is considered in more detail to demonstrate how beliefs about the supernatural world, and the shaman's relationship to this realm, were graphically portrayed.

Much rock art worldwide was traditionally interpreted in terms of “hunting magic,” in part based on the related concept of “sympathetic magic” In the last forty years, these interpretations were disproven in many regions and now are largely ignored as potential explanations for the origin and function of the art. In certain cases this may be premature. Examination of the ethnographic and archaeological evidence from western North America supports the origin of some art in sympathetic magic (often related to sorcery) in both California and the Plains and provides a case for hunting magic as one of a series of ritual reasons for making rock art in the Columbia Plateau. Both case studies emphasize the potential diversity in origin, function, and symbolism of shamanistic rock art.

David Lewis-Williams is well-known in rock-art circles as the author of a series of articles drawing on ethnographic material and shamanism (notably connected with the San rock art of southern Africa) to gain new insights into the Palaeolithic cave art of western Europe. Some 15 years ago, with Thomas Dowson, he proposed that Palaeolithic art owed its inspiration at least in part to trance experiences (altered states of consciousness) associated with shamanistic practices. Since that article appeared, the shamanistic hypothesis has both been widely adopted and developed in the study of different rock-art traditions, and has become the subject of lively and sometimes heated controversy. In the present volume, Lewis-Williams takes the argument further, and combines the shamanistic hypothesis with an interpretation of the development of human consciousness. He thus enters another contentious area of archaeological debate, seeking to understand west European cave art in the context of (and as a marker of) the new intellectual capacities of anatomically modern humans. Radiocarbon dates for the earliest west European cave art now place it contemporary with the demise of the Neanderthals around 30,000 years ago, and cave art, along with carved or decorated portable items, appears to announce the arrival and denote the success of modern humans in this region. Lewis-Williams argues that such cave art would have been beyond the capabilities of Neanderthals, and that this kind of artistic ability is unique to anatomically modern humans. Furthermore, he concludes that the development of the new ability cannot have been the product of hundreds of thousands of years of gradual hominid evolution, but must have arisen much more abruptly, within the novel neurological structure of anatomically modern humans. The Mind in the Cave is thus the product of two hypotheses, both of them contentious — the shamanistic interpretation of west European Upper Palaeolithic cave art, and the cognitive separation of modern humans and Neanderthals. But is it as simple as that? Was cave art the hallmark of a new cognitive ability and social consciousness that were beyond the reach of previous hominids? And is shamanism an outgrowth of the hard-wired structure of the modern human brain? We begin this Review Feature with a brief summary by David Lewis-Williams of the book's principal arguments. There follows a series of comments addressing both the meaning of the west European cave art, and its wider relevance for the understanding of the Neanderthal/modern human transition.

We consider the Clovis vs. pre-Clovis debate from three perspectives: migration models; petroglyph and surface-artifact ages; and scientific method. First, we test the hypothesis that a Clovis migration can account for the temporal and spatial distribution of South American Paleoindian sites “accepted” by Clovis-first advocates. Using a Clovis-first model, site ages are underpredicted by approximately 1,500 years, suggesting that the Clovis hypothesis cannot be reconciled with accepted empirical data. Second, we present North American accelerator mass spectrometry (AMS) 14C minimum-limiting ages from petroglyphs and surface artifacts that demonstrate continued support for a pre-Clovis occupation of the dryland west, as well as a Beringian entry into the hemisphere. Third, the debate has been confounded by a widespread misstatement of the problem. Though Clovis occupation is a “solved” issue, the competing hypotheses are whether the first migration was Clovis or pre-Clovis; the presence of Clovis sites is simply a necessary prediction of both migration theories. The empirical implications of the Clovis-first hypothesis are virtually untested. Scientifically evaluating the first peopling controversy requires scrutinizing the empirical test implications and logical coherency of both competing hypotheses.