The stratigraphy of the Penarth Group (Late Triassic) of the East Devon coast

The cliff and foreshore exposures in the Devon part of the Dorset and East Devon Coast World Heritage Site expose an unbroken late Triassic to early Jurassic succession. The change from the terrestrial, red-bed facies of the Triassic Mercia Mudstone Group to the fully marine conditions of the Jurassic Lias Group takes place via the Penarth Group, a succession of mudstones, siltstones and limestones deposited in lagoonal and sheltered shallow-marine environments of varying salinities. The Penarth Group as currently defined is divided into the Westbury Formation overlain by the Lilstock Formation, based on type sections in the Severn Estuary area. The lithology and sedimentology of the Westbury Formation strata exposed on the east Devon coast are closely comparable with those of the type area, but those of the Lilstock Formation are not. It is therefore proposed on lithological and historical grounds that this formation should be replaced by a Cotham Formation overlain by a White Lias Formation. This would reinstate, without any change in their original definitions, two of the oldest formally defined stratigraphical names in the British Phanerozoic. All three formations are lithologically distinctive, and are separated from their neighbours by erosion surfaces that represent non-sequences. Those at the bases of the Westbury and Cotham formations are overlain by pebble beds rich in vertebrate remains (‘bone beds’). The Cotham Formation is a highly condensed succession comprised of thinly interbedded mudstones and limestones with ripple trains, stromatolites, desiccated surfaces and slumped beds, the last of which have been attributed to earthquakes or a bolide impact. The limestones of the White Lias Formation exposed on the east Devon coast are sedimentologically complex with channels, slumps and desiccated surfaces. The position of the Triassic-Jurassic boundary is currently under review. Possible positions include the base of the Cotham Formation, a horizon within the formation, the base of the White Lias, the base of the overlying Blue Lias Formation or a horizon within the Blue Lias Formation

Zen history

Given that historians have a voracious interest in studying the distinctiveness of cultures aross the world and across time, why do they have so little interest in learning or borrowing from the temporal and historical cultures of those places? This essay offers a practical case study of Buddhism, looking both at the richness and radical difference of Buddhist temporalities, as well as asking how these ideas might be used by modern writers to make histories. Its special focus is on the Theravada and Māhāyana traditions, and, most especially, Zen. Through studies of Zen time texts, I conclude that an appreciation of Buddhist ‘history’ on its own terms might entail an abandonment of almost all the central premises of empirical history. This might become one starting point for the globalisation of History

The lexical violence of imperial culture

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThis article studies the history of a single word and its movement from pre-Islamic Arabia to the languages of modern Europe. It focuses on the key moment of the early nineteenth century when the Arabic ‘ghazwā’ served as the root and model of the French ‘razzia’ in the early Algerian colony. Tracing the history of the ghazwā through Islamic history and its subsequent emergence in Romance forms, the essay is comparative in the sense that it asks what happens in the movement of ideas and practices through loanwords. It suggests that the violence of modern empire was linguistic in a sense which encompasses the connections between thoughts, words and deeds, whilst critiquing literatures on lexical borrowing which tend to assume the innocence of linguistic exchange. A broader conclusion on transnational history is essayed through a consideration of the razzia in the context of the so-called ‘langue franque’: that métissage of Romance languages and Arabic which prevailed amongst traders across the Mediterranean in the early modern period, and which disappeared in the imperial Mediterranean of the nineteenth century

History goes walkabout

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Could the methods of history—and not just its objects of study—be decolonized? This essay explores analogous areas of cultural production, such as painting, to determine how historians might begin to produce work that lies outside the Western, Euro-Christian imaginary. It focuses on the case of Australia and the means by which Aboriginal artists have reanimated and recalibrated traditional forms of knowledge, offering new bases for thinking about the history and temporalities of Australia. The work of the painter Tim Johnson is then presented as an example for history in his demonstration of the ways in which indigenous methods and ways of seeing the world can be deployed by Others. The ethical, theoretical, and practical challenges that accompany such work are detailed, alongside a historiographical account of the way in which these discussions mesh with seminal debates in postcolonialism, subaltern studies, and settler colonialism as they relate to historical theory. Drawing on recent work in History and Theory, the article asks: what might be the consequences for history were it not to develop a meaningful “global turn,” arguing that a critical moment has been reached in which modes of understanding the world that come from outside the West need to be incorporated into historians’ repertoires for thinking and making

In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology

In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology

End of the Kiaman Superchron in the Permian of SW England: Magnetostratigraphy of the Aylesbeare Mudstone and Exeter groups

The chronology of Permian strata in SW England is fragmentary and largely based on radiometric dating of associated volcanic units. Magnetostratigraphy from the c. 2 km of sediments in the Exeter and Aylesbeare Mudstone groups was undertaken to define a detailed chronology, using the end of the Kiaman Superchron and the overlying reverse and normal polarity in the Middle and Upper Permian as age constraints. The palaeomagnetic directions are consistent with other European Permian palaeopoles, with data passing fold and reversal tests. The end of the Kiaman Superchron (in the Wordian) occurs in the uppermost part of the Exeter Group. The overlying Aylesbeare Mudstone Group is early Capitanian to latest Wuchiapingian in age. The Changhsingian and most of the Lower Triassic sequence is absent. Magnetostratigraphic comparison with the Southern Permian Basin shows that the Exeter and Aylesbeare Mudstone groups are closely comparable in age with the Havel and Elbe Subgroups of the Rotliegend II succession. The Altmark unconformities in these successions appear similar in age to the sequence boundaries in SW England, indicating that both may be climate controlled. Clasts in the Exeter Group, from unroofing of the Dartmoor Granite, first occurred at a minimum of c. 8 myr after formation of the granite

Attachment style, assertive communication, and safer-sex behavior

This research tested the proposition that the effect of attachment security on safer-sex practice may be mediated by communication patterns. One hundred eighty-five undergraduate students completed questionnaire measures of attachment, assertiveness, and attitudes to communication about AIDS. Eight weeks later, they reported on their practice of safer sex in the period since the first testing session. Hierarchical regressions showed that at Step 1, anxiety about relationships (a measure of insecure attachment) was associated with less safer-sex practice, for all outcome measures. Attitudes to communication about AIDS added to the prediction of general reports of safer-sex practice: in line with the mediational model, anxiety about relationships became unimportant as a predictor when communication variables were included. Communication variables failed to add to the prediction of safer sex on the most recent encounter, and both anxiety about relationships and attitudes to communication about AIDS predicted condom use. Some gender differences in patterns of prediction were noted. The results are discussed in terms of attachment style and its links with the negotiation of sexual practice and relationship issues

Identifying Potential Mechanisms Enabling Acidophily in the Ammonia-Oxidizing Archaeon "Candidatus Nitrosotalea devanaterra"

Ammonia oxidation is the first and rate-limiting step in nitrification and is dominated by two distinct groups of microorganisms in soil: ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). AOA are often more abundant than AOB and dominate activity in acid soils. The mechanism of ammonia oxidation under acidic conditions has been a long-standing paradox. While high rates of ammonia oxidation are frequently measured in acid soils, cultivated ammonia oxidizers grew only at near-neutral pH when grown in standard laboratory culture. Although a number of mechanisms have been demonstrated to enable neutrophilic AOB growth at low pH in the laboratory, these have not been demonstrated in soil, and the recent cultivation of the obligately acidophilic ammonia oxidizer “Candidatus Nitrosotalea devanaterra” provides a more parsimonious explanation for the observed high rates of activity. Analysis of the sequenced genome, transcriptional activity, and lipid content of “Ca. Nitrosotalea devanaterra” reveals that previously proposed mechanisms used by AOB for growth at low pH are not essential for archaeal ammonia oxidation in acidic environments. Instead, the genome indicates that “Ca. Nitrosotalea devanaterra” contains genes encoding both a predicted high-affinity substrate acquisition system and potential pH homeostasis mechanisms absent in neutrophilic AOA. Analysis of mRNA revealed that candidate genes encoding the proposed homeostasis mechanisms were all expressed during acidophilic growth, and lipid profiling by high-performance liquid chromatography–mass spectrometry (HPLC-MS) demonstrated that the membrane lipids of “Ca. Nitrosotalea devanaterra” were not dominated by crenarchaeol, as found in neutrophilic AOA. This study for the first time describes a genome of an obligately acidophilic ammonia oxidizer and identifies potential mechanisms enabling this unique phenotype for future biochemical characterization