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de Bezenac C.E.,University of Liverpool | Sluming V.,Thompson SCI | Gouws A.,York Neuroimaging Center iC | Corcoran R.,University of Liverpool
Biological Psychology | Year: 2016

In normal circumstances we can easily distinguish between changes to the external world brought about by our own actions from those with external causes. However, in certain contexts our sense of ownership and agency over acts is not so clear. Neuroimaging studies have implicated a number of regions in the sense of agency, some of which have been shown to vary continuously with action-outcome discordance. However, little is known about dynamic, ambiguous contexts characterised by a lack of information for self-other differentiation, yet such ambiguous states are important in relation to symptoms and levels of consciousness that characterise certain mental health conditions. With a block-design fMRI paradigm, we investigated neural responses to changes in the probability that a participant's irregular finger taps over 12 s would result in auditory tones as opposed to tones generated by ‘another's finger taps’. The main findings were that misattribution increased in ambiguous conditions where the probability of a tone belonging to self and other was equal. Task-sensitive brain regions, previously identified in self-agency, motor cognition, and ambiguity processing, showed a quadratic response to our self-to-other manipulation, with particular sensitivity to self-control. Task performance (low error and bias) was related to attenuated response in ambiguous conditions while increased response in regions associated with the default mode network was associated with greater overall error and bias towards other. These findings suggest that causal ambiguity as it occurs over time is a prominent feature in sense of agency, one that may eventually contribute to a more comprehensive understanding of positive symptoms of psychosis. © 2016


Tobin B.W.,Thompson SCI | Tobin B.W.,Texas State University | Schwartz B.F.,Texas State University
Hydrological Processes | Year: 2016

Hydrogeologic field work in remote settings is often challenging: assessing spring behaviour and aquifer characteristics can be expensive in both time commitment and resources needed to assess these systems. In this study, we document the hydrology and geochemistry of 47 perennial karst springs in the Kaweah River, a mountain river basin in the Sierra Nevada, California. After preliminary hydrogeochemical characterization and grouping, selected springs were continuously monitored to further assess aquifer characteristics in each group. Later, in areas without previous dye-tracing work, traces were conducted to establish connections between large sinking streams and springs. The springs have a wide range of inter-spring and intra-spring variability in discharge and geochemistry. We assessed this variability by performing statistical comparisons with spring chemistry and principal components analysis of all measured variables. Results show that springs can be divided into two distinct groups: high elevation springs of the Mineral King Valley and lower elevation springs throughout the rest of the basin. Continuous discharge, temperature and specific conductivity data from four springs (two from each group) were then used to characterize the hydrograph recession behaviour of springs in each group. Both groups showed statistically similar baseflow recession slopes, suggesting that both groups contain baseflow storage compartments with similar hydrogeologic properties. The biggest difference between each group is the variability in amount of water remaining in the aquifer during baseflow conditions. High elevation springs have lower baseflow discharges, relative to peak flow, than lower elevation springs, despite the fact that more precipitation falls at higher elevation. This is likely caused by differences in the amount of soil and epikarst storage, which are related to recent geomorphic events: high elevation aquifers were glaciated as recent as 41 thousand years ago (kya), while there is no evidence that low elevation aquifers were glaciated. As a result, lower elevations have developed thicker soils, weathered bedrock and epikarst. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.


Fredman S.J.,Pennsylvania State University | Vorstenbosch V.,Ryerson University | Vorstenbosch V.,Thompson SCI | Wagner A.C.,Ryerson University | And 3 more authors.
Journal of Anxiety Disorders | Year: 2014

Posttraumatic stress disorder (PTSD) is associated with myriad relationship problems and psychological distress in partners of individuals with PTSD. This study sought to develop a self-report measure of partner accommodation to PTSD (i.e., ways in which partners alter their behavior in response to patient PTSD symptoms), the Significant Others' Responses to Trauma Scale (SORTS), and to investigate its reliability and construct validity in 46 treatment-seeking couples. The SORTS demonstrated strong internal consistency and associations with individual and relationship distress. Accommodation was positively correlated with partners' ratings of patients' PTSD symptoms, patient self-reported depressive and trait anger severity, and partner self-reported depressive and state anger severity. Accommodation was negatively correlated with patient and partner relationship satisfaction and partners' perceived social support received from patients. Findings suggest that accommodation may be an attempt to adapt to living with a partner with PTSD but may have negative implications for patient and partner well-being. © 2014 Elsevier Ltd.


Elsayed A.,University of Liverpool | Coenen F.,University of Liverpool | Jiang C.,University of Liverpool | Garcia-Finana M.,University of Liverpool | Sluming V.,Thompson SCI
Knowledge-Based Systems | Year: 2010

An approach to classifying magnetic resonance (MR) image data is described. The specific application is the classification of MRI scan data according to the nature of the corpus callosum, however the approach has more general applicability. A variation of the "spectral segmentation with multi-scale graph decomposition" mechanism is introduced. The result of the segmentation is stored in a quad-tree data structure to which a weighted variation (also developed by the authors) of the gSpan algorithm is applied to identify frequent sub-trees. As a result the images are expressed as a set frequent sub-trees. There may be a great many of these and thus a decision tree based feature reduction technique is applied before classification takes place. The results show that the proposed approach performs both efficiently and effectively, obtaining a classification accuracy of over 95% in the case of the given application. © 2009 Elsevier B.V. All rights reserved.


Xu C.,Cold Spring Harbor Laboratory | Liberatore K.L.,Cold Spring Harbor Laboratory | Liberatore K.L.,U.S. Department of Agriculture | Macalister C.A.,Cold Spring Harbor Laboratory | And 15 more authors.
Nature Genetics | Year: 2015

Shoot meristems of plants are composed of stem cells that are continuously replenished through a classical feedback circuit involving the homeobox WUSCHEL (WUS) gene and the CLAVATA (CLV) gene signaling pathway. In CLV signaling, the CLV1 receptor complex is bound by CLV3, a secreted peptide modified with sugars. However, the pathway responsible for modifying CLV3 and its relevance for CLV signaling are unknown. Here we show that tomato inflorescence branching mutants with extra flower and fruit organs due to enlarged meristems are defective in arabinosyltransferase genes. The most extreme mutant is disrupted in a hydroxyproline O-arabinosyltransferase and can be rescued with arabinosylated CLV3. Weaker mutants are defective in arabinosyltransferases that extend arabinose chains, indicating that CLV3 must be fully arabinosylated to maintain meristem size. Finally, we show that a mutation in CLV3 increased fruit size during domestication. Our findings uncover a new layer of complexity in the control of plant stem cell proliferation. © 2015 Nature America, Inc. All rights reserved.


McMaster M.A.,Northern Arizona University | Thode A.,Northern Arizona University | Kearsley M.,Thompson SCI
International Journal of Wildland Fire | Year: 2015

Seeding following high-severity wildfires is motivated by the goals of increasing vegetative cover and decreasing bare soil in order to minimise soil erosion and exotic plant invasions. We compared the ground cover and vegetation response of seeded versus non-seeded areas located in the Warm Fire in northern Arizona, where post-fire seeding treatments with Italian ryegrass (Lolium perenne spp. multiflorum (L.)) were conducted in 4000ha of high-severity burned areas. Over the course of the study, we observed no significant difference between seeded and non-seeded plots in percentage of bare soil, total vegetative cover or exotic plant cover. However, there were significant differences in plant community composition as revealed by PERMANOVA and Indicator Species Analysis. Two years post-fire there were significantly fewer ponderosa pine seedlings, and the cover of annual and biennial forbs was significantly lower in plots that were seeded with Italian ryegrass. In the third year, the cover of native bunch grasses was significantly lower in seeded plots. The differences we observed may be due to differences in pre-existing vegetation composition because of the geographic separation of the plots across the landscape. Our results illustrate the ineffectiveness of post-fire seeding in achieving the goals of increasing vegetative cover and decreasing the invasion of non-native plants, and we suggest that alternative post-fire remediation should be considered in the future. © 2015 IAWF.


Barnes H.M.,Thompson SCI | Hill J.M.,Mississippi State University
Wood and Fiber Science | Year: 2016

This research investigated the effects of specimen width on the flexural properties of laboratorymanufactured, fire retardant-treated strandboard. In this study, fire retardant-treated and untreated 864- by 864- by 10.5-mm strandboard panels were manufactured in the laboratory. Each panel was edge trimmed and cut into five specimens of various widths. Each specimen was then tested in four-point flexure across a 648-mm span. We assessed the effect of strandboard specimen width on the stability of mean and variance estimates. It is critical to recognize specimen width as an important experimental factor because the size and orientation of individual flakes and strands in narrow-width strandboard test specimens can influence the magnitude and variability of test results. The bending properties of 305-mm-wide strandboard specimens, and to a lesser extent those of 203-mm-wide specimens, were consistently greater than the 102- and 152-mm-wide treated groups. Variability of flexure results, based on coefficient of variation, was for the most part uniform. The internal bond strength was consistent at all widths tested. © 2016 by the Society of Wood Science and Technology.


PubMed | University of Liverpool and Thompson SCI
Type: Journal Article | Journal: Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie | Year: 2016

To determine the effect of changing illuminance on visual and stereo acuity.Twenty-eight subjects aged 21 to 60years were assessed. Monocular visual acuity (ETDRS) of emmetropic subjects was assessed under 15 different illuminance levels (50-8000 lux), provided by a computer controlled halogen lighting rig. Three levels of myopia (-0.50DS, -1.00DS & 1.50DS) were induced in each subject using lenses and visual acuity (VA) was retested under the same illuminance conditions. Stereoacuity (TNO) was assessed under the same levels of illuminance.A one log unit change in illuminance level (lx) results in a significant change of 0.060 LogMAR (p<0.001), an effect that is exacerbated in the presence of induced myopic refractive error (p<0.001). Stereoacuity scores demonstrate statistically significant overall differences between illuminance levels (p<0.001).The findings of this study demonstrate that changes in illuminance have a statistically significant effect on VA that may contribute to test/retest variability. Increases in illuminance from 50 to 500lx resulted in an improved VA score of 0.12 LogMAR. Differences like these have significant clinical implications, such as false negatives during vision screening and non-detection of VA deterioration, as the full magnitude of any change may be hidden. In research where VA is a primary outcome measure, differences of 0.12 LogMAR or even less could affect the statistical significance and conclusions of a study. It is recommended that VA assessment always be performed between 400lx and 600lx, as this limits any effect of illuminance change to 0.012 LogMAR.


PubMed | University of Richmond, University of Oxford, Thompson SCI, University of New South Wales and University of Sydney
Type: | Journal: Physical therapy | Year: 2016

Tai chi is recommended for musculoskeletal conditions; however, the evidence for its clinical effectiveness is uncertain.The aim of this study was to determine whether tai chi is beneficial for clinical outcomes in people with musculoskeletal pain.Seven databases were searched: Embase, PEDro, AMED, MEDLINE, CINAHL, SPORTDiscus, and the Cochrane Central Register of Controlled Trials.Randomized controlled trials of tai chi for people with a chronic musculoskeletal condition were included.Two reviewers extracted data and rated risk of bias. Standardized mean differences (SMDs) and 95% confidence intervals (CI) were calculated for individual trials and pooled effect sizes were calculated using a random-effects model.Fifteen studies were identified; these studies included people with osteoarthritis (80%), back pain (13%), and headache (7%). Using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach, moderate-quality evidence was found that tai chi was more effective than no treatment or usual care at short term on pain (SMD=-0.66 [95% CI=-0.85, -0.48]) and disability (SMD=-0.66 [95% CI=-0.85, -0.46]). The evidence for other outcomes was of low or very low quality and there was little information regarding long-term effects. Thus, although the number of publications in this area has increased, the rigor has not, hindering physical therapists ability to provide reliable recommendations for clinical practice.The evidence provided in this review is limited by trials with small sample sizes, low methodological quality, and lack of long-term assessment.In order for tai chi to be recommended as an effective intervention, more high-quality trials with large sample sizes assessing tai chi versus other evidence-based treatments at short term and at long term are needed.


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