Late- to post-Variscan extensional tectonics in south Cornwall

Faults which post-date Variscan contractional deformation are ubiquitous in south Cornwall. Three broad geometric/kinematic types can be defined. The first type comprises low angle (dip <45°) extensional faults which exhibit listric or ramp and flat geometries and may display complex arrangements of secondary faults and folds in their hangingwalls. In some instances they host elvans and "mainstage" magmatic-hydrothermal lodes (more rarely lamprophyres). The second type are moderate to high angle (dip >45°) extensional faults which generally offset earlier low-angle faults; they frequently host elvans and "mainstage" magmatichydrothermal lodes. The third type are high-angle faults which usually exhibit dominant strike-slip displacement, offset all previous faults and are often associated with base metal mineralization. Collectively these structures exerted a strong control on granite emplacement, mineralization and the development of offshore sedimentary basins. The approximately coeval association of potassic volcanicity, granite magmatism, extensional faulting and sedimentary basin development was probably a consequence of late Carboniferous to early Permian collapse of previously thickened lithosphere

The role of post-Variscan extensional tectonics and mantle melting in the generation of the Lower Permian granites and the giant W-As-Sn-Cu-Zn-Pb orefield of SW England

Copyright © 2003 Maney Publishin

Tectonic evolution of the Plymouth Bay Basin

A synthesis of offshore seismic data in the Plymouth Bay and Western Approaches, and onshore basement structures and mineralisation history has allowed new constraints to be placed on the structural evolution of the late Carboniferous- Triassic Plymouth Bay Basin. These data have been combined to produce a model for the late- and post- Variscan tectonics of the Plymouth Bay area. Additional controls on the timing and magnitude of Variscan uplift and late-Variscan low-angle extensional deformation onshore are used to infer a late Carboniferous age for the earliest basin fill. These sediments were accommodated in a northeast — south-west oriented basin formed during late-orogenic extension. A change in the orientation of the depocentre in the early Permian signalled a switch to a north-west — south-east, strike-slip dominated tectonic environment

Curing resin infused composites in the autoclave

There is increasing interest across the range of composites manufacturing processes for cost reduction with a current focus on out-of-autoclave (OOA) processes. However, for the highest performance composites, the maximum fibre volume fraction is limited by the compressibility characteristics of the reinforcement. For any specific reinforcement, vacuum-only processes cannot achieve fibre contents as high when additional external pressure is applied. Compression moulding in a hydraulic press creates limited compaction perpendicular to the line of action of the press. The autoclave is good for complex three-dimensional components. Autoclave processes normally use pre-impregnated reinforcements with a premium price for the impregnation process and the associated quality issues. The use of dry reinforcements infused with liquid resins should lead to significant cost reductions. This paper considers the optimisation of autoclave cure for resin-infused composites and extends an earlier feasibility study for composite plates referenced to equivalent systems manufactured by hand-lamination, or by resin infusion without autoclave cure. Consolidation at 5.9 bar lead to an additional 8.4% (thickness method) or 8.6% (burnoff) fibre volume fraction. In turn, the flexural modulus was increased by 39% and the flexural strength was increased by 20% relative to vacuum-only cured composites

No Detectable Fertility Benefit from a Single Additional Mating in Wild Stalk-Eyed Flies

Background: Multiple mating by female insects is widespread, and the explanation(s) for repeated mating by females has been the subject of much discussion. Females may profit from mating multiply through direct material benefits that increase their own reproductive output, or indirect genetic benefits that increase offspring fitness. One particular direct benefit that has attracted significant attention is that of fertility assurance, as females often need to mate multiply to achieve high fertility. This hypothesis has never been tested in a wild insect population.Methodology/Principal Findings: Female Malaysian stalk-eyed flies (Teleopsis dalmanni) mate repeatedly during their lifetime, and have been shown to be sperm limited under both laboratory and field conditions. Here we ask whether receiving an additional mating alleviates sperm limitation in wild females. In our experiment one group of females received a single additional mating, while a control group received an interrupted, and therefore unsuccessful, mating. Females that received an additional mating did not lay more fertilised eggs in total, nor did they lay proportionately more fertilised eggs. Female fertility declined significantly through time, demonstrating that females were sperm limited. However, receipt of an additional mating did not significantly alter the rate of this decline.Conclusions/Significance: Our data suggest that the fertility consequences of a single additional mating were small. We discuss this effect (or lack thereof), and suggest that it is likely to be attributed to small ejaculate size, a high proportion of failed copulations, and the presence of X-linked meiotic drive in this species

Neuropsychological Deficits Are Correlated with Frontal Hypometabolism in Positron Emission Tomography Studies of Older Alcoholic Patients

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66315/1/j.1530-0277.1993.tb00750.x.pd

Implementing health research through academic and clinical partnerships : a realistic evaluation of the Collaborations for Leadership in Applied Health Research and Care (CLAHRC)

Background: The English National Health Service has made a major investment in nine partnerships between higher education institutions and local health services called Collaborations for Leadership in Applied Health Research and Care (CLAHRC). They have been funded to increase capacity and capability to produce and implement research through sustained interactions between academics and health services. CLAHRCs provide a natural ‘test bed’ for exploring questions about research implementation within a partnership model of delivery. This protocol describes an externally funded evaluation that focuses on implementation mechanisms and processes within three CLAHRCs. It seeks to uncover what works, for whom, how, and in what circumstances. Design and methods: This study is a longitudinal three-phase, multi-method realistic evaluation, which deliberately aims to explore the boundaries around knowledge use in context. The evaluation funder wishes to see it conducted for the process of learning, not for judging performance. The study is underpinned by a conceptual framework that combines the Promoting Action on Research Implementation in Health Services and Knowledge to Action frameworks to reflect the complexities of implementation. Three participating CLARHCS will provide indepth comparative case studies of research implementation using multiple data collection methods including interviews, observation, documents, and publicly available data to test and refine hypotheses over four rounds of data collection. We will test the wider applicability of emerging findings with a wider community using an interpretative forum. Discussion: The idea that collaboration between academics and services might lead to more applicable health research that is actually used in practice is theoretically and intuitively appealing; however the evidence for it is limited. Our evaluation is designed to capture the processes and impacts of collaborative approaches for implementing research, and therefore should contribute to the evidence base about an increasingly popular (e.g., Mode two, integrated knowledge transfer, interactive research), but poorly understood approach to knowledge translation. Additionally we hope to develop approaches for evaluating implementation processes and impacts particularly with respect to integrated stakeholder involvement

Tracking of unpredictable moving stimuli by pigeons

Despite being observed throughout the animal kingdom, catching a moving object is a complex task and little is known about the mechanisms that underlie this behavior in non-human animals. Three experiments examined the role of prediction in capture of a moving object by pigeons. In Experiment 1, a stimulus moved in a linear trajectory, but sometimes made an unexpected 90o turn. The sudden turn had only a modest effect on capture and error location, and the analyses suggested that the birds had adjusted their tracking to the novel motion. In Experiment 2, the role of visual input during a turn was tested by inserting disappearances (either 1.5 cm or 4.5 cm) on both the straight and turn trials. The addition of the disappearance had little effect on capture success, but delayed capture location with the larger disappearance leading to greater delay. Error analyses indicated that the birds adapted to the post-turn, post-disappearance motion. Experiment 3 tested the role of visual input when the motion disappeared behind an occluder and emerged in either a straight line or at a 90o angle. The occluder produced a disruption in capture success but did not delay capture. Error analyses indicated that the birds did not adjust their tracking to the new motion on turn trials following occlusion. The combined results indicate that pigeons can anticipate the future position of a stimulus, and can adapt to sudden, unpredictable changes in motion but do so better after a disappearance than after an occlusion

Contribution of Various Carbon Sources Toward Isoprene Biosynthesis in Poplar Leaves Mediated by Altered Atmospheric CO2 Concentrations

Biogenically released isoprene plays important roles in both tropospheric photochemistry and plant metabolism. We performed a 13CO2-labeling study using proton-transfer-reaction mass spectrometry (PTR-MS) to examine the kinetics of recently assimilated photosynthate into isoprene emitted from poplar (Populus × canescens) trees grown and measured at different atmospheric CO2 concentrations. This is the first study to explicitly consider the effects of altered atmospheric CO2 concentration on carbon partitioning to isoprene biosynthesis. We studied changes in the proportion of labeled carbon as a function of time in two mass fragments, M41+, which represents, in part, substrate derived from pyruvate, and M69+, which represents the whole unlabeled isoprene molecule. We observed a trend of slower 13C incorporation into isoprene carbon derived from pyruvate, consistent with the previously hypothesized origin of chloroplastic pyruvate from cytosolic phosphenolpyruvate (PEP). Trees grown under sub-ambient CO2 (190 ppmv) had rates of isoprene emission and rates of labeling of M41+ and M69+ that were nearly twice those observed in trees grown under elevated CO2 (590 ppmv). However, they also demonstrated the lowest proportion of completely labeled isoprene molecules. These results suggest that under reduced atmospheric CO2 availability, more carbon from stored/older carbon sources is involved in isoprene biosynthesis, and this carbon most likely enters the isoprene biosynthesis pathway through the pyruvate substrate. We offer direct evidence that extra-chloroplastic rather than chloroplastic carbon sources are mobilized to increase the availability of pyruvate required to up-regulate the isoprene biosynthesis pathway when trees are grown under sub-ambient CO2