380 research outputs found

    The Stratigraphic Record of Pre-breakup Geodynamics: Evidence from the Barrow Delta, offshore Northwest Australia

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    The structural and stratigraphic evolution of rift basins and passive margins has been widely studied, with many analyses demonstrating that delta systems can provide important records of post-rift geodynamic processes. However, the apparent lack of ancient syn-breakup delta systems and the paucity of seismic imaging across continent-ocean boundaries means the transition from continental rifting to oceanic spreading remains poorly understood. The Early Cretaceous Barrow Group of the North Carnarvon Basin, offshore NW Australia was a major deltaic system that formed during the latter stages of continental rifting, and represents a rich sedimentary archive, documenting uplift, subsidence and erosion of the margin. We use a regional database of 2D and 3D seismic and well data to constrain the internal architecture of the Barrow Group. Our results highlight three major depocentres: the Exmouth and Barrow sub-basins, and southern Exmouth Plateau. Over-compaction of pre-Cretaceous sedimentary rocks in the South Carnarvon Basin, and pervasive reworking of Permian and Triassic palynomorphs in the offshore Barrow Group, suggests that the onshore South Carnarvon Basin originally contained a thicker sedimentary succession, which was uplifted and eroded prior to breakup. Backstripping of sedimentary successions encountered in wells in the Exmouth Plateau depocentre indicate anomalously rapid tectonic subsidence (ā‰¤0.24 mm yr-1) accommodated Barrow Group deposition, despite evidence for minimal, contemporaneous upper crustal extension. Our results suggest that classic models of uniform extension cannot account for the observations of uplift and subsidence in the North Carnarvon Basin, and may indicate a period of depth-dependent extension or dynamic topography preceding breakup

    Tectonic and oceanographic process interactions archived in Late Cretaceous to Present deepā€marine stratigraphy on the Exmouth Plateau, offshore NW Australia

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    Deepā€marine deposits provide a valuable archive of process interactions between sediment gravity flows, pelagic sedimentation and thermohaline bottomā€currents. Stratigraphic successions can also record plateā€scale tectonic processes (e.g. continental breakup and shortening) that impact longā€term ocean circulation patterns, including changes in climate and biodiversity. One such setting is the Exmouth Plateau, offshore NW Australia, which has been a relatively stable, fineā€grained carbonateā€dominated continental margin from the Late Cretaceous to Present. We combine extensive 2D (~40,000 km) and 3D (3,627 km2) seismic reflection data with lithologic and biostratigraphic information from wells to reconstruct the tectonic and oceanographic evolution of this margin. We identified three largeā€scale seismic units (SUs): (a) SUā€1 (Late Cretaceous)ā€”500 mā€thick, and characterised by NEā€SWā€trending, slopeā€normal elongate depocentres (c. 200 km long and 70 km wide), with erosional surfaces at their bases and tops, which are interpreted as the result of contourā€parallel bottomā€currents, coeval with the onset of opening of the Southern Ocean; (b) SUā€2 (Palaeoceneā€”Late Miocene)ā€”800 mā€thick and characterised by: (a) very large (amplitude, c. 40 m and wavelength, c. 3 km), SWā€migrating, NWā€SEā€trending sediment waves, (b) large (4 kmā€wide, 100 mā€deep), NEā€trending scours that flank the sediment waves and (c) NWā€trending, 4 kmā€wide and 80 mā€deep turbidite channel, infilled by NEā€dipping reflectors, which together may reflect an intensification of NEā€flowing bottom currents during a relative seaā€level fall following the establishment of circumpolarā€ocean current around Antarctica; and (c) SUā€3 (Late Mioceneā€”Present)ā€”1,000 mā€thick and is dominated by large (up to 100 km3) massā€transport complexes (MTCs) derived from the continental margin (to the east) and the Exmouth Plateau Arch (to the west), and accumulated mainly in the adjacent Kangaroo Syncline. This change in depositional style may be linked to tectonicallyā€induced seabed tilting and folding caused by collision and subduction along the northern margin of the Australian plate. Hence, the stratigraphic record of the Exmouth Plateau provides a rich archive of plateā€scale regional geological events occurring along the distant southern (2,000 km away) and northern (1,500 km away) margins of the Australian plate

    Stratigraphic record of continental breakup, offshore NW Australia

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    Continental breakup involves a transition from rapid, fault-controlled syn-rift subsidence to relatively slow, post-breakup subsidence induced by lithospheric cooling. Yet the stratigraphic record of many rifted margins contain syn-breakup unconformities, indicating that episodes of uplift and erosion interrupt this transition. This uplift has been linked to mantle upwelling, depth-dependent extension and/or isostatic rebound. Deciphering the breakup processes recorded by these unconformities and their related rock record is challenging because uplift-associated erosion commonly removes the strata that help constrain the onset and duration of uplift. We examine three major breakup-related unconformities and the intervening rock record in the Lower Cretaceous succession of the Gascoyne and Cuvier margins, offshore NW Australia, using seismic reflection and borehole data. These data show the breakup unconformities are disconformable (non-erosive) in places and angular (erosive) in others. Our recalibration of palynomorph ages from rocks underlying and overlying the unconformities shows: (i) the lowermost unconformity developed between 134.98ā€“133.74 Ma (Intra-Valanginian), probably during the localisation of magma intrusion within continental crust and consequent formation of continentā€“ocean transition zones (COTZ); (ii) the middle unconformity formed between ca. 134 and 133 Ma (Top Valanginian), possibly coincident with breakup of continental crust and generation of new magmatic (but not oceanic) crust within the COTZs; and (iii) the uppermost unconformity likely developed between ca. 132.5 and 131 Ma (i.e. Intra-Hauterivian), coincident with full continental lithospheric breakup and the onset of seafloor spreading. During unconformity development, uplift was focussed along the continental rift flanks, likely reflecting flexural bending of the crust and landward flow of lower crust and/or lithospheric mantle from beneath areas of localised extension towards the continent (i.e. depth-dependent extension). Our work supports the growing consensus that the ā€˜breakup unconformityā€™ is not always a single stratigraphic surface marking the onset of seafloor spreading; multiple unconformities may form and reflect a complex history of uplift and subsidence during continentā€“ocean transition

    Behavior therapy for pediatric trichotillomania: Exploring the effects of age on treatment outcome

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    <p>Abstract</p> <p>Background</p> <p>A randomized controlled trial examining the efficacy of behavior therapy for pediatric trichotillomania was recently completed with 24 participants ranging in age from 7 - 17. The broad age range raised a question about whether young children, older children, and adolescents would respond similarly to intervention. In particular, it is unclear whether the younger children have the cognitive capacity to understand concepts like "urges" and whether they are able to introspect enough to be able to benefit from awareness training, which is a key aspect of behavior therapy for trichotillomania.</p> <p>Methods</p> <p>Participants were randomly assigned to receive either behavior therapy (N = 12) or minimal attention control (N = 12), which was included to control for repeated assessments and the passage of time. Primary outcome measures were the independent evaluator-rated NIMH-Trichotillomania Severity Scale, a semi-structured interview often used in trichotillomania treatment trials, and a post-treatment clinical global impression improvement rating (CGI-I).</p> <p>Results</p> <p>The correlation between age and change in symptom severity for all patients treated in the trial was small and not statistically significant. A 2 (group: behavioral therapy, minimal attention control) Ɨ 2 (time: week 0, 8) Ɨ 2 (children < 9 yrs., children > 10) ANOVA with independent evaluator-rated symptom severity scores as the continuous dependent variable also detected no main effects for age or for any interactions involving age. In light of the small sample size, the mean symptom severity scores at weeks 0 and 8 for younger and older patients randomized to behavioral therapy were also plotted. Visual inspection of these data indicated that although the groups appeared to have started at similar levels of severity for children ā‰¤ 9 vs. children ā‰„ 10; the week 8 data show that the three younger children did at least as well as if not slightly better than the nine older children and adolescents.</p> <p>Conclusions</p> <p>Behavior therapy for pediatric trichotillomania appears to be efficacious even in young children. The developmental and clinical implications of these findings will be discussed.</p> <p>Trial Registration</p> <p>Clinicaltrials.gov NCT00043563.</p

    Does physiotherapy reduce the incidence of postoperative complications in patients following pulmonary resection via thoracotomy? a protocol for a randomised controlled trial

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    Background: Postoperative pulmonary and shoulder complications are important causes of postoperative morbidity following thoracotomy. While physiotherapy aims to prevent or minimise these complications, currently there are no randomised controlled trials to support or refute effectiveness of physiotherapy in this setting. Methods/Design: This single blind randomised controlled trial aims to recruit 184 patients following lung resection via open thoracotomy. All subjects will receive a preoperative physiotherapy information booklet and following surgery will be randomly allocated to a Treatment Group receiving postoperative physiotherapy or a Control Group receiving standard care nursing and medical interventions but no physiotherapy. The Treatment Group will receive a standardised daily physiotherapy programme to prevent respiratory and musculoskeletal complications. On discharge Treatment Group subjects will receive an exercise programme and exercise diary to complete. The primary outcome measure is the incidence of postoperative pulmonary complications, which will be determined on a daily basis whilst the patient is in hospital by a blinded assessor. Secondary outcome measures are the length of postoperative hospital stay, severity of pain, shoulder function as measured by the self-reported shoulder pain and disability index, and quality of life measured by the Medical Outcomes Study Short Form 36 v2 New Zealand standard version. Pain, shoulder function and quality of life will be measured at baseline, on discharge from hospital, one month and three months postoperatively. Additionally a subgroup of subjects will have measurement of shoulder range of movement and muscle strength by a blinded assessor. Discussion: Results from this study will contribute to the increasing volume of evidence regarding the effectiveness of physiotherapy following major surgery and will guide physiotherapists in their interventions for patients following thoracotomy. Trial registration: The study protocol is registered with the Australian and New Zealand Clinical Trials registry (ANZCTRN12605000201673)

    Corrigendum to: Cohort profile: Extended Cohort for E-health, Environment and DNA (EXCEED)

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    This is a correction to: International Journal of Epidemiology, Volume 48, Issue 3, June 2019, Pages 678ā€“679j, https://doi.org/10.1093/ije/dyz07

    Development of an intervention to improve appropriate polypharmacy in older people in primary care using a theory-based method

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    BACKGROUND: It is advocated that interventions to improve clinical practice should be developed using a systematic approach and intervention development methods should be reported. However, previous interventions aimed at ensuring that older people receive appropriate polypharmacy have lacked details on their development. This study formed part of a multiphase research project which aimed to develop an intervention to improve appropriate polypharmacy in older people in primary care. METHODS: The target behaviours for the intervention were prescribing and dispensing of appropriate polypharmacy to older patients by general practitioners (GPs) and community pharmacists. Intervention development followed a systematic approach, including previous mapping of behaviour change techniques (BCTs) to key domains from the Theoretical Domains Framework that were perceived by GPs and pharmacists to influence the target behaviours. Draft interventions were developed to operationalise selected BCTs through team discussion. Selection of an intervention for feasibility testing was guided by a subset of the APEASE (Affordability, Practicability, Effectiveness/cost-effectiveness, Acceptability, Side-effects/safety, Equity) criteria. RESULTS: Three draft interventions comprising selected BCTs were developed, targeting patients, pharmacists and GPs, respectively. Following assessment of each intervention using a subset of the APEASE criteria (affordability, practicability, acceptability), the GP-targeted intervention was selected for feasibility testing. This intervention will involve a demonstration of the behaviour and will be delivered as an online video. The video demonstrating how GPs can prescribe appropriate polypharmacy during a typical consultation with an older patient will also demonstrate salience of consequences (feedback emphasising the positive outcomes of performing the behaviour). Action plans and prompts/cues will be used as complementary intervention components. The intervention is designed to facilitate the prescribing of appropriate polypharmacy in routine practice. CONCLUSION: A GP-targeted intervention to improve appropriate polypharmacy in older people has been developed using a systematic approach. Intervention content has been specified using an established taxonomy of BCTs and selected to maximise feasibility. The results of a future feasibility study will help to determine if the theory-based intervention requires further refinement before progressing to a larger scale randomised evaluation

    Validation of the conceptual research utilization scale: an application of the standards for educational and psychological testing in healthcare

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    <p>Abstract</p> <p>Background</p> <p>There is a lack of acceptable, reliable, and valid survey instruments to measure conceptual research utilization (CRU). In this study, we investigated the psychometric properties of a newly developed scale (the CRU Scale).</p> <p>Methods</p> <p>We used the <it>Standards for Educational and Psychological Testing </it>as a validation framework to assess four sources of validity evidence: content, response processes, internal structure, and relations to other variables. A panel of nine international research utilization experts performed a formal content validity assessment. To determine response process validity, we conducted a series of one-on-one scale administration sessions with 10 healthcare aides. Internal structure and relations to other variables validity was examined using CRU Scale response data from a sample of 707 healthcare aides working in 30 urban Canadian nursing homes. Principal components analysis and confirmatory factor analyses were conducted to determine internal structure. Relations to other variables were examined using: (1) bivariate correlations; (2) change in mean values of CRU with increasing levels of other kinds of research utilization; and (3) multivariate linear regression.</p> <p>Results</p> <p>Content validity index scores for the five items ranged from 0.55 to 1.00. The principal components analysis predicted a 5-item 1-factor model. This was inconsistent with the findings from the confirmatory factor analysis, which showed best fit for a 4-item 1-factor model. Bivariate associations between CRU and other kinds of research utilization were statistically significant (p < 0.01) for the latent CRU scale score and all five CRU items. The CRU scale score was also shown to be significant predictor of overall research utilization in multivariate linear regression.</p> <p>Conclusions</p> <p>The CRU scale showed acceptable initial psychometric properties with respect to responses from healthcare aides in nursing homes. Based on our validity, reliability, and acceptability analyses, we recommend using a reduced (four-item) version of the CRU scale to yield sound assessments of CRU by healthcare aides. Refinement to the wording of one item is also needed. Planned future research will include: latent scale scoring, identification of variables that predict and are outcomes to conceptual research use, and longitudinal work to determine CRU Scale sensitivity to change.</p

    Social conditions of becoming homelessness: qualitative analysis of life stories of homeless peoples

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    Background It is increasingly acknowledged that homelessness is a more complex social and public health phenomenon than the absence of a place to live. This view signifies a paradigm shift, from the definition of homelessness in terms of the absence of permanent accommodation, with its focus on pathways out of homelessness through the acquisition and maintenance of permanent housing, to understanding the social context of homelessness and social interventions to prevent it. However, despite evidence of the association between homelessness and social factors, there is very little research that examines the wider social context within which homelessness occurs from the perspective of homeless people themselves. This study aims to examine the stories of homeless people to gain understanding of the social conditions under which homelessness occurs, in order to propose a theoretical explanation for it. Method Twenty-six semi-structured interviews were conducted with homeless people in three centres for homeless people in Cheshire North West of England. Results The analysis revealed that becoming homeless is a process characterised by a progressive waning of resilience capacity to cope with life challenges created by series of adverse incidents in oneā€™s life. The data show that final stage in the process of becoming homeless is complete collapse of relationships with those close to them. Most prominent pattern of behaviours participants often describe as main causes of breakdown of their relationships are: 1. engaging in maladaptive behavioural lifestyle including taking drugs and/or excessive alcohol drinking 2. Being in trouble with people in authorities. Conclusion Homeless people describe the immediate behavioural causes of homelessness, however, the analysis revealed the social and economic conditions within which homelessness occurred. The participantsā€™ descriptions of the social conditions in which were raised and their references to maladaptive behaviours which led to them becoming homeless, led us to conclude that they believe that their social condition affected their life chances: that these conditions were responsible for their low quality of social connections, poor educational attainment, insecure employment and other reduced life opportunities available to them

    Optimal Resting-Growth Strategies of Microbial Populations in Fluctuating Environments

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    Bacteria spend most of their lifetime in non-growing states which allow them to survive extended periods of stress and starvation. When environments improve, they must quickly resume growth to maximize their share of limited nutrients. Cells with higher stress resistance often survive longer stress durations at the cost of needing more time to resume growth, a strong disadvantage in competitive environments. Here we analyze the basis of optimal strategies that microorganisms can use to cope with this tradeoff. We explicitly show that the prototypical inverse relation between stress resistance and growth rate can explain much of the different types of behavior observed in stressed microbial populations. Using analytical mathematical methods, we determine the environmental parameters that decide whether cells should remain vegetative upon stress exposure, downregulate their metabolism to an intermediate optimum level, or become dormant. We find that cell-cell variability, or intercellular noise, is consistently beneficial in the presence of extreme environmental fluctuations, and that it provides an efficient population-level mechanism for adaption in a deteriorating environment. Our results reveal key novel aspects of responsive phenotype switching and its role as an adaptive strategy in changing environments
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