103 research outputs found

    Vibronic coupling in the superoxide anion: The vibrational dependence of the photoelectron angular distribution

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    We present a comprehensive photoelectron imaging study of the Oā‚‚(XĀ³Ī£gā»,vā€²=0ā€“6)ā†Oā‚‚ā»(XĀ²Ī g,vā€²ā€²=0) and Oā‚‚(aĀ¹Ī”g,vā€²=0ā€“4)ā†Oā‚‚ā»(XĀ²Ī g,vā€²ā€²=0)photodetachment bands at wavelengths between 900 and 455 nm, examining the effect of vibronic coupling on the photoelectron angular distribution (PAD). This work extends the vā€²=1ā€“4 data for detachment into the ground electronic state, presented in a recent communication [R. Mabbs, F. Mbaiwa, J. Wei, M. Van Duzor, S. T. Gibson, S. J. Cavanagh, and B. R. Lewis, Phys. Rev. A82, 011401ā€“R (2010)]. Measured vibronic intensities are compared to Franckā€“Condon predictions and used as supporting evidence of vibronic coupling. The results are analyzed within the context of the one-electron, zero core contribution (ZCC) model [R. M. Stehman and S. B. Woo, Phys. Rev. A23, 2866 (1981)]. For both bands, the photoelectron anisotropy parameter variation with electron kinetic energy,Ī²(E), displays the characteristics of photodetachment from a d-like orbital, consistent with the Ļ€āˆ—g 2p highest occupied molecular orbital of Oā‚‚ā». However, differences exist between the Ī²(E) trends for detachment into different vibrational levels of the XĀ³Ī£gā» and aā€‰Ā¹Ī”g electronic states of Oā‚‚. The ZCC model invokes vibrational channel specific ā€œdetachment orbitalsā€ and attributes this behavior to coupling of the electronic and nuclear motion in the parent anion. The spatial extent of the model detachment orbital is dependent on the final state of Oā‚‚: the higher the neutral vibrational excitation, the larger the electron binding energy. Although vibronic coupling is ignored in most theoretical treatments of PADs in the direct photodetachment of molecular anions, the present findings clearly show that it can be important. These results represent a benchmark data set for a relatively simple system, upon which to base rigorous tests of more sophisticated models.The authors gratefully acknowledge support by the National Science Foundation Grant No. CHE-0748738 and ANU ARC Discovery Projects under Grant Nos. DP0666267 and DP0880850

    Comunicazione italiana nel mondo: interviste a distanza. Prove d'Europa a Radio Colonia

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    Lā€™Europa ĆØ di casa a Radio Colonia, lā€™emittente italiana del WDR, Westdeutscher Rundfunk, lā€™ente radiotelevisivo pubblico del Land Nord Reno-Westfalia, che il primo dicembre scorso ha celebrato il mezzo secolo di vita. Il suo direttore, Tommaso Pedicini, ricorda i motivi che portarono alla nascita della Radio, nel 1961, in un periodo in cui esplodeva il fenomeno dellā€™emigrazione italiana in Germania ed i Gastarbeiter (ā€œlavoratori ospitiā€) italiani avevano bisogno di una voce amica. Da allora molti sono stati i cambiamenti, ma Radio Colonia ĆØ rimasta la finestra italiana nel panorama radiofonico tedesco, impegnata in particolare, dopo lā€™avvio nel 1999 della Funkhaus Europa, a coltivare i temi del plurilinguismo e dellā€™integrazione degli immigrati

    Vibronic coupling in the superoxide anion: the vibrational dependence of the photoelectron angular distribution

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    We present a comprehensive photoelectron imaging study of the O2(Xā€‰3Ī£gāˆ’,vā€² = 0ā€“6)ā†O2āˆ’(Xā€‰2Ī g,vā€³ = 0) and O2(aā€‰1Ī”g,vā€² = 0ā€“4)ā†O2āˆ’(Xā€‰2Ī g,vā€³ = 0) photodetachment bands at wavelengths between 900 and 455 nm, examining the effect of vibronic coupling on the photoelectron angular distribution (PAD). This work extends the vā€² = 1ā€“4 data for detachment into the ground electronic state, presented in a recent communication. Measured vibronic intensities are compared to Franckā€“Condon predictions and used as supporting evidence of vibronic coupling. The results are analyzed within the context of the one-electron, zero core contribution (ZCC) model. For both bands, the photoelectron anisotropy parameter variation with electron kinetic energy, Ī²(E), displays the characteristics of photodetachment from a d-like orbital, consistent with the Ļ€gāˆ— 2p highest occupied molecular orbital of O2āˆ’. However, differences exist between the Ī²(E) trends for detachment into different vibrational levels of the Xā€‰3Ī£gāˆ’ and aā€‰1Ī”g electronic states of O2. The ZCC model invokes vibrational channel specific ā€œdetachment orbitalsā€ and attributes this behavior to coupling of the electronic and nuclear motion in the parent anion. The spatial extent of the model detachment orbital is dependent on the final state of O2: the higher the neutral vibrational excitation, the larger the electron binding energy. Although vibronic coupling is ignored in most theoretical treatments of PADs in the direct photodetachment of molecular anions, the present findings clearly show that it can be important. These results represent a benchmark data set for a relatively simple system, upon which to base rigorous tests of more sophisticated models

    Testing for parameter instability in predictive regression models

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    We consider tests for structural change, based on the SupF and Cramer-von-Mises type statistics of Andrews (1993) and Nyblom (1989), respectively, in the slope and/or intercept parameters of a predictive regression model where the predictors display strong persistence. The SupF type tests are motivated by alternatives where the parameters display a small number of breaks at deterministic points in the sample, while the Cramer-von-Mises alternative is one where the coefficients are random and slowly evolve through time. In order to allow for an unknown degree of persistence in the predictors, and for both conditional and unconditional heteroskedasticity in the data, we implement the tests using a fixed regressor wild bootstrap procedure. The asymptotic validity of the bootstrap tests is established by showing that the asymptotic distributions of the bootstrap parameter constancy statistics, conditional on the data, coincide with those of the asymptotic null distributions of the corresponding statistics computed on the original data, conditional on the predictors. Monte Carlo simulations suggest that the bootstrap parameter stability tests work well in finite samples, with the tests based on the Cramer-von-Mises type principle seemingly the most useful in practice. An empirical application to U.S. stock returns data demonstrates the practical usefulness of these methods

    Transcriptomic analysis of wheat near-isogenic lines identifies PM19-A1 and A2 as candidates for a major dormancy QTL

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    BACKGROUND: Next-generation sequencing technologies provide new opportunities to identify the genetic components responsible for trait variation. However, in species with large polyploid genomes, such as bread wheat, the ability to rapidly identify genes underlying quantitative trait loci (QTL) remains non-trivial. To overcome this, we introduce a novel pipeline that analyses, by RNA-sequencing, multiple near-isogenic lines segregating for a targeted QTL. RESULTS: We use this approach to characterize a major and widely utilized seed dormancy QTL located on chromosome 4AL. It exploits the power and mapping resolution afforded by large multi-parent mapping populations, whilst reducing complexity by using multi-allelic contrasts at the targeted QTL region. Our approach identifies two adjacent candidate genes within the QTL region belonging to the ABA-induced Wheat Plasma Membrane 19 family. One of them, PM19-A1, is highly expressed during grain maturation in dormant genotypes. The second, PM19-A2, shows changes in sequence causing several amino acid alterations between dormant and non-dormant genotypes. We confirm that PM19 genes are positive regulators of seed dormancy. CONCLUSIONS: The efficient identification of these strong candidates demonstrates the utility of our transcriptomic pipeline for rapid QTL to gene mapping. By using this approach we are able to provide a comprehensive genetic analysis of the major source of grain dormancy in wheat. Further analysis across a diverse panel of bread and durum wheats indicates that this important dormancy QTL predates hexaploid wheat. The use of these genes by wheat breeders could assist in the elimination of pre-harvest sprouting in wheat.Jose M. Barrero, Colin Cavanagh, Klara L. Verbyla, Josquin F.G. Tibbits, Arunas P. Verbyla, B. Emma Huang, Garry M. Rosewarne, Stuart Stephen, Penghao Wang, Alex Whan, Philippe Rigault, Matthew J. Hayden, and Frank Guble

    Prediction models in first-episode psychosis: systematic review and critical appraisal

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    Background: People presenting with first-episode psychosis (FEP) have heterogenous outcomes. More than 40% fail to achieve symptomatic remission. Accurate prediction of individual outcome in FEP could facilitate early intervention to change the clinical trajectory and improve prognosis. Aims: We aim to systematically review evidence for prediction models developed for predicting poor outcome in FEP. Method: A protocol for this study was published on the International Prospective Register of Systematic Reviews, registration number CRD42019156897. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance, we systematically searched six databases from inception to 28 January 2021. We used the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies and the Prediction Model Risk of Bias Assessment Tool to extract and appraise the outcome prediction models. We considered study characteristics, methodology and model performance. Results: Thirteen studies reporting 31 prediction models across a range of clinical outcomes met criteria for inclusion. Eleven studies used logistic regression with clinical and sociodemographic predictor variables. Just two studies were found to be at low risk of bias. Methodological limitations identified included a lack of appropriate validation, small sample sizes, poor handling of missing data and inadequate reporting of calibration and discrimination measures. To date, no model has been applied to clinical practice. Conclusions: Future prediction studies in psychosis should prioritise methodological rigour and external validation in larger samples. The potential for prediction modelling in FEP is yet to be realised

    Hair glucocorticoids are associated with childhood adversity, depressive symptoms and reduced global and lobar grey matter in Generation Scotland

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    ACKNOWLEDGEMENTS We would like to thank all of the Generation Scotland participants for their contribution to this study. We also thank the research assistants, clinicians and technicians for their help in collecting the data. Generation Scotland received core support from the Chief Scientist Office of the Scottish Government Health Directorates [CZD/16/6] and the Scottish Funding Council [HR03006] and is currently supported by the Wellcome Trust [216767/Z/19/Z]. This study was also supported and funded by the Wellcome Trust Strategic Award ā€˜Stratifying Resilience and Depression Longitudinallyā€™ (STRADL) (Reference 104036/Z/14/Z). We acknowledge the support of the British Heart Foundation (RE/18/5/34216). CG is supported by the Medical Research Council and the University of Edinburgh through the Precision Medicine Doctoral Training Programme. MCB is supported by a Guarantors of Brain Non-Clinical Post-Doctoral Fellowship. JMW is funded by the UK Dementia Research Institute which is funded by the UK Medical Research Council, Alzheimerā€™s Research UK and Alzheimerā€™s SocietyPeer reviewedPublisher PD

    Using the spring-mass model for running : force-length curves and foot-strike patterns

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    Background: The spring-mass model is commonly used to investigate the mechanical characteristics of human running. Underlying this model is the assumption of a linear force-length relationship, during the stance phase of running, and the idea that stiffness can be characterised using a single spring constant. However, it remains unclear whether the assumption of linearity is valid across different running styles. Research question: How does the linearity of the force-length curve vary across a sample of runners and is there an association between force-length linearity and foot-strike index/speed? Methods: Kinematic and kinetic data were collected from twenty-eight participants who ran overground at four speeds. The square of the Pearsonā€™s correlation coefficient, R2 , was used to quantify linearity; with a threshold of R 2 ā‰„ 0.95 selected to define linear behaviour. A linear mixed model was used to investigate the association between linearity and foot-strike index and speed. Results: Only 36-46 % of participants demonstrated linear force-length behaviour across the four speeds during the loading phase. Importantly, the linear model showed a significant effect of both foot-strike index and speed on linearity during the loading phase (p = 0.003 and p < 0.001, respectively). Significance: This study showed that the assumption of a linear force-length relationship is not appropriate for all runners. These findings suggest that the use of the spring-mass model, and a constant value of stiffness, may not be appropriate for characterising and comparing different running styles. Given these findings, it may be better to restrict the use of the spring-mass model to individuals who exhibit linear force-length dependence. It would also be appropriate for future studies, characterising stiffness using the spring-mass model, to report data on force-length linearity across the cohort under study

    Structural brain correlates of serum and epigenetic markers of inflammation in major depressive disorder

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    Funding Information: Generation Scotland received core support from the Chief Scientist Office of the Scottish Government Health Directorates [CZD/16/6] and the Scottish Funding Council [HR03006] and is currently supported by the Wellcome Trust [216767/Z/19/Z]. Genotyping of the GS:SFHS samples was carried out by the Genetics Core Laboratory at the Edinburgh Clinical Research Facility, University of Edinburgh, Scotland and was funded by the Medical Research Council UK and the Wellcome Trust (Wellcome Trust Strategic Award ā€œSTratifying Resilience and Depression Longitudinallyā€ (STRADL) Reference 104036/Z/14/Z). CG is supported by The Medical Research Council and The University of Edinburgh through the Precision Medicine Doctoral Training program. SRC is supported by the UK Medical Research Council [MR/R024065/1] and a National Institutes of Health (NIH) research grant R01AG054628. Acknowledgements The authors thank all of the STRADL and Generation Scotland participants for their time and effort taking part in this study. We would also like to thank all of the research assistants, clinicians and technicians for their help in the collecting this data.Peer reviewedPublisher PD

    Differential antibody responses to Plasmodium falciparum merozoite proteins in Malawian children with severe malaria

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    Cerebral malaria (CM) and severe malarial anemia (SMA) are 2 major causes of death in African children infected with Plasmodium falciparum. We investigated levels of naturally acquired antibody to conserved and variable regions of merozoite surface protein (MSP)-1 and MSP-2, apical membrane antigen (AMA)-1, and rhoptry-associated protein 1 in plasma samples from 126 children admitted to the hospital with CM, 59 with SMA, and 84 with uncomplicated malaria (UM) in Malawi. Children with SMA were distinguished by very low levels of immunoglobulin (Ig) G to the conserved C-terminus of MSP-1 and MSP-2 and to full-length AMA-1. Conversely, children with CM had significantly higher levels of IgG to the conserved regions of all antigens examined than did children with UM (for MSP-1 and AMA-1, P&lt; .005; for MSP-2, P&lt; .05) or SMA (for MSP-1 and MSP-2, P&lt;.001; for AMA-1, P&lt; .005). These distinct IgG patterns might reflect differences in age, exposure to P. falciparum, and/or genetic factors affecting immune responses
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