New Paleomagnetic Data From Thurston Island: Implications for the Tectonics of West Antarctica and Weddell Sea Opening

Paleomagnetic data from three West Antarctic crustal blocks (Antarctic Peninsula (AP), Thurston Island-Eights Coast (TI), and the Ellsworth-Whitmore Mountains (EWM) indicate that there has been motion between the individual blocks and motion relative to East Antarctica during the Mesozoic. A Triassic paleomagnetic pole from the TI block (116°E, 61°S, A_95 = 19.4°, N = 3 VGPs) appears to indicate that the block has rotated ~90° relative to East Antarctica between 230 Ma and 110 Ma. Our previously reported Middle Jurassic paleomagnetic pole from the EWM block indicates that a 90° rotation relative to East Antarctica occurred sometime between the Cambrian and 175 Ma. We believe that the 90° counterclockwise EWM rotation occurred between ~220 Ma and 175 Ma related to the development of post-Gondwanide Orogeny shear zones. The motion of the AP, TI, and EWM blocks appears to be linked during the mid- to late Mesozoic to three major events in the evolution of the southern ocean basins. Opening in the Mozambique-Somali-Weddell Sea basins may have produced major counterclockwise rotation of the TI block with respect to East Antarctica between the Jurassic and Early Cretaceous based on new Late Jurassic (145°E, 64.5°S, A_95 = 7°,N = 5 VGPs) poles. We believe that the TI rotation, as well as deformation in the southern AP block, was caused by collision and shearing of the EWM block against the other two as the EWM block moved southward with East Antarctica. An Early Cretaceous paleomagnetic pole (232°E, 49°S, A_95 = 7.9°, N = 5 VGPs) from the TI block requires that between the Early and mid- Cretaceous there was clockwise rotation, with respect to East Antarctica, of the AP-TI-EWM blocks (an entity we call Weddellia). A change in the opening history of the Weddell Sea basin caused by initiation of spreading in the South Atlantic ocean basin at ~130 Ma probably started Weddellia's clockwise rotation. Two new ~110 and ~90 Ma poles from the TI block (210°E, 73°S, A_95 = 7.6°,N = 7 VGPs and 161°E, 81°S, A_95= 3.9°,N = 18 VGPs, respectively) are similar to equivalent age poles from the AP block and East Antarctica and indicate that Weddellia was at or near its present-day position with respect to East Antarctica by ~110 Ma. This corresponds to a time of major plate reorganization in the South Atlantic and southeast Indian Oceans. Based on both the new TI paleomagnetic data and previously reported data from Marie Byrd Land (MBL), dextral shearing would be expected to have occurred between MBL and Weddellia since the mid-Cretaceous. Pine Island Bay, the area between the TI and MBL blocks, marks a fundamental and complex tectonic boundary in West Antarctica that we propose has largely been a zone of transcurrent shearing

Ellsworth-Whitmore Mountains Crustal Block, Western Antarctica: New paleomagnetic results and their tectonic significance

Preliminary paleomagnetic study of granitic and sedimentary rocks from the Ellsworth-Whitmore Mountains crustal block (EVH), Vest Antarctica, leads to the following conclusions: (1) The EVH has a paleogole for the Middle Jurassic located at 235°E, 41°S, (α₉₅ = 5.3, N = 8 sites) assuming that no widespread regional tilting has occurred since the magnetization measured was acquired. A Middle Jurassic paleolatitude of 47°S is indicated for the sites and precludes an original location for the EVH block south of the Antarctic Peninsula crustal block (AP). (2) This pole is not significantly different from the previously published Middle Jurassic paleopole obtained from rocks of the northern Antarctic Peninsula. The combined AP-EVH paleopole, compared to the Middle Jurassic mean paleopole obtained from igneous rocks of the Ferrar Supergroup in East Antarctica, suggests about 15° tectonic clockwise rotation of the AP and EVH. Since the AP and EVH poles coincide, these two crustal blocks may have moved as one unit since the Middle Jurassic. ( 3) The new data are compatible with two different Gondwanaland reconstructions. The first considers the AP and EVH as separate entities. The second is based on the movement of the AP and EVH as one block. For the Middle Jurassic, both reconstructions would locate the EVH west of Coats Land and south of the Falkland Plateau, with the adjacent AP located south of southernmost South America. (4) Enigmas concerning the structural trend and isolation of the thick Ellsworth Mountains Paleozoic succession persist

Neoproterozoic to early Paleozoic extensional and compressional history of East Laurentian margin sequences: The Moine Supergroup, Scottish Caledonides

Neoproterozoic siliciclastic-dominated sequences are widespread along the eastern margin of Laurentia and are related to rifting associated with the breakout of Laurentia from the supercontinent Rodinia. Detrital zircons from the Moine Supergroup, NW Scotland, yield Archean to early Neoproterozoic U-Pb ages, consistent with derivation from the Grenville-Sveconorwegian orogen and environs and accumulation post–1000 Ma. U-Pb zircon ages for felsic and associated mafic intrusions confirm a widespread pulse of extension-related magmatism at around 870 Ma. Pegmatites yielding U-Pb zircon ages between 830 Ma and 745 Ma constrain a series of deformation and metamorphic pulses related to Knoydartian orogenesis of the host Moinerocks. Additional U-Pb zircon and monazite data, and 40Ar/39Ar ages for pegmatites and host gneisses indicate high-grade metamorphic events at ca. 458–446 Ma and ca. 426 Maduring the Caledonian orogenic cycle.The presence of early Neoproterozoic silici clastic sedimentation and deformation in the Moine and equivalent successions around the North Atlantic and their absence along strike in eastern North America reflect contrasting Laurentian paleogeography during the breakup of Rodinia. The North Atlantic realm occupied an external location on the margin of Laurentia, and this region acted as a locus for accumulation of detritus (Moine Supergroup and equivalents) derived from the Grenville-Sveconorwegian orogenic welt, which developed as a consequence of collisional assembly of Rodinia. Neoproterozoic orogenic activity corresponds with theinferred development of convergent platemargin activity along the periphery of the supercontinent. In contrast in eastern North America, which lay within the internal parts of Rodinia, sedimentation did not commence until the mid-Neoproterozoic (ca. 760 Ma) during initial stages of supercontinent fragmentation. In the North Atlantic region, this time frame corresponds to a second pulse of extension represented by units such as the Dalradian Supergroup, which unconformably overlies the predeformed Moine succession

Revealing the crustal architecture of the least understood composite craton on Earth: East Antarctica

East Antarctica hosts one of the largest Precambrian cratons on Earth. Meager coastal exposures and sediment provenance studies provide glimpses into up to 3 billion years of its geological history. Extensive ice sheet cover hampers however our knowledge of crustal architecture, and consequently the geodynamic processes responsible for the growth and amalgamation of East Antarctica have remained elusive. Here we exploit recent aerogeophysical exploration efforts to help unveil the large-scale crustal architecture of East Antarctica. We focus on three sectors of East Antarctica: the Transantarctic Mountains and Wilkes Basin area; the Recovery/Dronning Maud Land area and the Gamburtsev Province. These areas provide new insights into both the margins of the so called Mawson craton and the processes that affected its interior. A 1,900 km-long linear magnetic and gravity boundary is imaged along the western flank of the Wilkes Basin and interpreted here as a crustal-scale Paleoproterozoic suture zone (ca 1.7 Ga) that inverted a former passive margin. Two ribbon-like Archean and Paleoproterozic microcontinents were assembled during this stage, resembling modes of amalgamation of Paleoproterozoic microcontinental ribbons in Australia. The proposed Proterozoic sutures and microcontinent boundaries also influenced Neoproterozoic rifted margin and early Cambrian back-arc basins in the Wilkes Basin/Transantarctic Mountains region. In the Recovery/Dronning Maud Land region our new potential field compilations reveal a wide tract of anastomising crustal-scale shear zones, likely of Pan-African age that flank and variably deform the margins of several distinct Archean, Paleo-Mesoproterozoic and Grenvillian age crustal blocks. In the Gamburtsev Province new magnetic and gravity models provide insights into the Gamburtsev Suture (Ferraccioli et al., 2011, Nature) that separates the Ruker Province from an inferred Grenvillian-age orogenic Gamburtsev Province with remarkably thick crust (up to 60 km thick) and thick lithosphere (over 200 km thick). We suggest that a recently inferred Tonian-age accretionary belt identified in the Sor Rondane region continues further inland in the Gamburtsev Province and was likely also reactivated during Pan-African age transpression linked to Gondwana assembly

New Views of East Antarctica- from Columbia to Gondwana

East Antarctica is a keystone in the Gondwana, Rodinia and the Columbia supercontinents. Recent aerogeophysical research, augmented by satellite magnetic, gravity and seismological data is unveiling the crustal architecture of the continent. This is helping comprehend the impact of supercontinental processes such as subduction, accretion, rifting and intraplate tectonics on its evolution. A mosaic of Precambrian basement provinces is apparent in interior East Antarctica (Ferraccioli et al., 2011, Nature). A major suture separates the Archean-Neoproterozoic Ruker Province from an inferred Grenvillian-age orogenic Gamburtsev Province with remarkably thick crust (up to 60 km thick) and thick lithosphere (over 200 km thick). The age of the suturing and its linkages with supercontinental assembly is debated with both Rodinia and Gondwana candidates being proposed. Further east, magnetic highs delineate a Paleo to Mesoproterozoic Nimrod-South Pole igneous province (Goodge and Finn, 2010 JGR) that flanks a composite Mawson Continent- including the Gawler Craton of South Australia (Aitken et al., 2014 GRL). An over 1,900 km long magnetic and gravity lineament is imaged along the western flank of the Wilkes Subglacial Basin and is interpreted here as a major Paleoproterozoic suture zone linked to the collision of Laurentia and East Antarctica within Columbia. The proposed suture played a pivotal role helping localise Neoproterozoic Rodinia rifted margin evolution and forming a backstop for the Ross-Delamerian cycle of Gondwana amalgamation. Aeromagnetic and gravity imaging help determine the extent of a Keweenawan-age (ca 1.1 Ga) large igneous province in the Coats Land Block -isotopically tied with the Mid-Continent Rift System of Laurentia (Loewy et al., 2011 Geology). Imprints of Grenvillian magmatic arc accretion link together the Namaqua-Natal and Maud belts in South Africa and Dronning Maud Land within Rodinia. The aeromagnetically distinct Southeast Dronning Maud Land province (Mieth and Jokat, 2014 GR) may represent a separate 1000-900 Ma Oceanic Arc Superterrane (Jacobs et al., 2015 Prec. Res.). New geophysical views of the Shackleton Range suture lend weight to more complex collisional and indentation tectonic models for the Pan-African age assembly of Gondwan

National Survey for Salmonella in Pigs at Slaughter in Great Britain

In the first randomised National Survey for Salmonella in slaughter pigs in Great Britain, 2509 pigs were sampled in 34 abattoirs in England, Scotland and Wales. Caecal carriage of Salmonella was identified in 578 (23.0% pigs) but in only 135 (5.3%) of carcase swabs. The predominant Salmonella serovars found in both types of sample were S.Typhimurium (11.1% caeca, 2.1% carcases) and S.Derby (6.3% caeca, 1.6% carcases). The main definitive phage types of S.Typhimurium found were DTI04 (21.9% of caecal S.Typhimurium isolates), DTI93 (18.7%), untypable strains (17.6%), DT208 (13.3%) and U302 (13.3%). 3 isolates of S.Enteritidis (PTs 13A and 4) and I enrofloxacin resistant S.Choleraesuis were also found. 15.2% of pigs gave a positive \u27meat-juice ELISA\u27 result at the 40% optical density (OD) cut-off level and 35.7% at the 10% cut-off. There was poor correlation between positive ELISA results or carcase contamination and the caecal carriage of Salmonella. The ratio of carcase contamination to caecal carriage rates was highest in abattoirs from the Midlands region of England and in smaller abattoirs. There was also a statistically significant correlation between Salmonella carriage and the presence of Enterococcus faecium or Yersinia enteroco/itica in the same pig

Varicella-Zoster viruses associated with post-herpetic neuralgia induce sodium current density increases in the ND7-23 Nav-1.8 neuroblastoma cell line

Post-herpetic neuralgia (PHN) is the most significant complication of herpes zoster caused by reactivation of latent Varicella-Zoster virus (VZV). We undertook a heterologous infection in vitro study to determine whether PHN-associated VZV isolates induce changes in sodium ion channel currents known to be associated with neuropathic pain. Twenty VZV isolates were studied blind from 11 PHN and 9 non-PHN subjects. Viruses were propagated in the MeWo cell line from which cell-free virus was harvested and applied to the ND7/23-Nav1.8 rat DRG x mouse neuroblastoma hybrid cell line which showed constitutive expression of the exogenous Nav 1.8, and endogenous expression of Nav 1.6 and Nav 1.7 genes all encoding sodium ion channels the dysregulation of which is associated with a range of neuropathic pain syndromes. After 72 hrs all three classes of VZV gene transcripts were detected in the absence of infectious virus. Single cell sodium ion channel recording was performed after 72 hr by voltage-clamping. PHN-associated VZV significantly increased sodium current amplitude in the cell line when compared with non-PHN VZV, wild-type (Dumas) or vaccine VZV strains ((POka, Merck and GSK). These sodium current increases were unaffected by acyclovir pre-treatment but were abolished by exposure to Tetrodotoxin (TTX) which blocks the TTX-sensitive fast Nav 1.6 and Nav 1.7 channels but not the TTX-resistant slow Nav 1.8 channel. PHN-associated VZV sodium current increases were therefore mediated in part by the Nav 1.6 and Nav 1.7 sodium ion channels. An additional observation was a modest increase in message levels of both Nav1.6 and Nav1.7 mRNA but not Nav 1.8 in PHN virally infected cells

The cost of changing physical activity behaviour: Evidence from a "physical activity pathway" in the primary care setting

Copyright @ 2011 Boehler et al.BACKGROUND: The ‘Physical Activity Care Pathway’ (a Pilot for the ‘Let’s Get Moving’ policy) is a systematic approach to integrating physical activity promotion into the primary care setting. It combines several methods reported to support behavioural change, including brief interventions, motivational interviewing, goal setting, providing written resources, and follow-up support. This paper compares costs falling on the UK National Health Service (NHS) of implementing the care pathway using two different recruitment strategies and provides initial insights into the cost of changing physical activity behaviour. METHODS: A combination of a time driven variant of activity based costing, audit data through EMIS and a survey of practice managers provided patient-level cost data for 411 screened individuals. Self reported physical activity data of 70 people completing the care pathway at three month was compared with baseline using a regression based ‘difference in differences’ approach. Deterministic and probabilistic sensitivity analyses in combination with hypothesis testing were used to judge how robust findings are to key assumptions and to assess the uncertainty around estimates of the cost of changing physical activity behaviour. RESULTS: It cost £53 (SD 7.8) per patient completing the PACP in opportunistic centres and £191 (SD 39) at disease register sites. The completer rate was higher in disease register centres (27.3% vs. 16.2%) and the difference in differences in time spent on physical activity was 81.32 (SE 17.16) minutes/week in patients completing the PACP; so that the incremental cost of converting one sedentary adult to an ‘active state’ of 150 minutes of moderate intensity physical activity per week amounts to £ 886.50 in disease register practices, compared to opportunistic screening. CONCLUSIONS: Disease register screening is more costly than opportunistic patient recruitment. However, additional costs come with a higher completion rate and better outcomes in terms of behavioural change in patients completing the care pathway. Further research is needed to rigorously evaluate intervention efficiency and to assess the link between behavioural change and changes in quality adjusted life years (QALYs).This article is available through the Brunel Open Access Publishing Fund

Trends in absolute socioeconomic inequalities in mortality in Sweden and New Zealand. A 20-year gender perspective

BACKGROUND: Both trends in socioeconomic inequalities in mortality, and cross-country comparisons, may give more information about the causes of health inequalities. We analysed trends in socioeconomic differentials by mortality from early 1980s to late 1990s, comparing Sweden with New Zealand. METHODS: The New Zealand Census Mortality Study (NZCMS) consisting of over 2 million individuals and the Swedish Survey of Living Conditions (ULF) comprising over 100, 000 individuals were used for analyses. Education and household income were used as measures of socioeconomic position (SEP). The slope index of inequality (SII) was calculated to estimate absolute inequalities in mortality. Analyses were based on 3–5 year follow-up and limited to individuals aged 25–77 years. Age standardised mortality rates were calculated using the European population standard. RESULTS: Absolute inequalities in mortality on average over the 1980s and 1990s for both men and women by education were similar in Sweden and New Zealand, but by income were greater in Sweden. Comparing trends in absolute inequalities over the 1980s and 1990s, men's absolute inequalities by education decreased by 66% in Sweden and by 17% in New Zealand (p for trend <0.01 in both countries). Women's absolute inequalities by education decreased by 19% in Sweden (p = 0.03) and by 8% in New Zealand (p = 0.53). Men's absolute inequalities by income decreased by 51% in Sweden (p for trend = 0.06), but increased by 16% in New Zealand (p = 0.13). Women's absolute inequalities by income increased in both countries: 12% in Sweden (p = 0.03) and 21% in New Zealand (p = 0.04). CONCLUSION: Trends in socioeconomic inequalities in mortality were clearly most favourable for men in Sweden. Trends also seemed to be more favourable for men than women in New Zealand. Assuming the trends in male inequalities in Sweden were not a statistical chance finding, it is not clear what the substantive reason(s) was for the pronounced decrease. Further gender comparisons are required