2,320 research outputs found

    Word frequency predicts translation asymmetry

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    Bilingualism studies report asymmetries in word processing across languages. Access to L2 words is slower and sensitive to semantic blocking. These observations inform influential models of bilingual processing, which propose autonomous lexicons with different processing routes. In a series of experiments, we explored an alternative hypothesis that the asymmetries are due to frequency of use. Using a within-language ā€˜translationā€™ task, involving high/low frequency (HF/LF) synonyms, we obtained parallel results to bilingual studies. Experiment 1 revealed that HF synonyms were accessed faster than LF ones. Experiment 2 showed that semantic blocking slowed retrieval only of LF synonyms, while form blocking produced powerful interference of both HF and LF words. Experiment 3 examined translation speed and sensitivity to blocking in two groups of Russian-English bilinguals who differed in frequency of use of their languages. Translation asymmetries were modulated by frequency of use. The results support an integrated lexicon model of bilingual processing

    First Principles Study of Ferroelectricity in Halide Perovskites for Future Photoferroics

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    Perovskite and perovskite-like materials have garnered warranted attention over the previous decade due to their potential use in high efficiency photovoltaic devices. Their flexibility both chemically and sterically gives materials' scientists and engi- neers the opportunity to tune the properties of such materials to suit the application that it is needed for. In this thesis we use ab initio methods to describe the funda- mental distortions that appear in a series of structures and their associated optoelec- tronic properties. In the first results chapter we complete a rigorous exploration of a variety of chemistries where we explore the various distortions that can appear in these materials. I show that the system exhibits a very complex interplay between pri- marily the breathing distortion and Jahn-Teller distortion and subsequently all other distortions that appear at lower tolerance factors. We also explore the appearance of a polar instability. In the second results chapter we take the understanding of these distortions and physical aspects of the gold double perovskites to discuss the opto- electronic properties of these materials. We find that the Jahn-Teller distortion opens up the gap in a metallic to insulator phase transition, we examine the effects of each of the distortions on the size of the gap and the effective masses of the structures and we see that the introduction of tilt distortions opens up the gap even more and increases the effective masses of the charge carriers. Examination of pressure presented us with the unusual discovery that hydrostatic pressure suppresses the appearance of the tilt distortions in this perovskite structure due to the cooperative nature between the tilt and Jahn-Teller distortions(something that is suppressed with pressure). With the knowledge of the effects of pressure we predicted a polar phase in the Rb2Au2(Br, I)6 structures with the introduction of a small hydrostatic pressure. We explored the pos- sibility of an enhanced dielectric constant through tuning of lattice parameters with pressure and was able to show an enhanced dielectric constant at a region where the phonon frequency was sufficiently softened. In the final part of the thesis we dis- cussed the application of hybrid improper ferroelectricity. We showed through sym- metry analysis that a polar distortion appears in the low-symmetry A3B2X7(A = Cs, Rb, K; B = Pb, Sn, Ge; X = I, Br, Cl) Ruddlesden-Popper structures via a trilinear coupling term with two non-polar distortions. We explored the effect of chemical substitution on the size of the gap and the effects each change in the chemistry had on the size of the distortions, we suggested that the Cs3Ge2I7 system is a proper ferroelectric (does not follow the improper method) and finally we explored the effects of Spin-Orbit coupling and the type of exchange-correlation functional that was used on the ac- curacy of our results. Overall we believe that the work presented in this review puts forward some exciting and interesting discussions of charge-separation in perovskite photovoltaics. As we look forward in this review we make some suggestions of other structures which would be more suitable for a possible experimental analysis

    High-sensitivity troponin I concentrations are a marker of an advanced hypertrophic response and adverse outcomes in patients with aortic stenosis

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    Aims: High-sensitivity cardiac troponin I (cTnI) assays hold promise in detecting the transition from hypertrophy to heart failure in aortic stenosis. We sought to investigate the mechanism for troponin release in patients with aortic stenosis and whether plasma cTnI concentrations are associated with long-term outcome. Methods and results: Plasma cTnI concentrations were measured in two patient cohorts using a high-sensitivity assay. First, in the Mechanism Cohort, 122 patients with aortic stenosis (median age 71, 67% male, aortic valve area 1.0 Ā± 0.4 cm2) underwent cardiovascular magnetic resonance and echocardiography to assess left ventricular (LV) myocardial mass, function, and fibrosis. The indexed LV mass and measures of replacement fibrosis (late gadolinium enhancement) were associated with cTnI concentrations independent of age, sex, coronary artery disease, aortic stenosis severity, and diastolic function. In the separate Outcome Cohort, 131 patients originally recruited into the Scottish Aortic Stenosis and Lipid Lowering Trial, Impact of REgression (SALTIRE) study, had long-term follow-up for the occurrence of aortic valve replacement (AVR) and cardiovascular deaths. Over a median follow-up of 10.6 years (1178 patient-years), 24 patients died from a cardiovascular cause and 60 patients had an AVR. Plasma cTnI concentrations were associated with AVR or cardiovascular death HR 1.77 (95% CI, 1.22 to 2.55) independent of age, sex, systolic ejection fraction, and aortic stenosis severity. Conclusions: In patients with aortic stenosis, plasma cTnI concentration is associated with advanced hypertrophy and replacement myocardial fibrosis as well as AVR or cardiovascular death

    The UCL Ventura CPAP device for COVID-19

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    Molecular characterisation of viruses from Kiwifruit

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    In 2003 Apple stem grooving virus was discovered in Actinidia accessions from China, being held in quarantine in Auckland. Subsequent examination of kiwifruit germplasm from the same source has detected several additional viruses, including a ~300 nm rigid rod related to Ribgrass mosaic virus (Tobamovirus), a 700-750 nm flexuous virus related to Citrus leaf blotch virus (Flexiviridae) and a novel vitivirus. Currently these viruses have not been reported from commercial kiwifruit crops in New Zealand or elsewhere. The biological properties of the viruses from kiwifruit and their phylogenetic relationships with similar viruses from other plants will be described, and the possible implications for the international movement of Actinidia germplasm are discussed

    RSSsite: a reference database and prediction tool for the identification of cryptic Recombination Signal Sequences in human and murine genomes

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    Recombination signal sequences (RSSs) flanking V, D and J gene segments are recognized and cut by the VDJ recombinase during development of B and T lymphocytes. All RSSs are composed of seven conserved nucleotides, followed by a spacer (containing either 12 Ā± 1 or 23 Ā± 1 poorly conserved nucleotides) and a conserved nonamer. Errors in V(D)J recombination, including cleavage of cryptic RSS outside the immunoglobulin and T cell receptor loci, are associated with oncogenic translocations observed in some lymphoid malignancies. We present in this paper the RSSsite web server, which is available from the address http://www.itb.cnr.it/rss. RSSsite consists of a web-accessible database, RSSdb, for the identification of pre-computed potential RSSs, and of the related search tool, DnaGrab, which allows the scoring of potential RSSs in user-supplied sequences. This latter algorithm makes use of probability models, which can be recasted to Bayesian network, taking into account correlations between groups of positions of a sequence, developed starting from specific reference sets of RSSs. In validation laboratory experiments, we selected 33 predicted cryptic RSSs (cRSSs) from 11 chromosomal regions outside the immunoglobulin and TCR loci for functional testing

    Predicting Climate-Driven Coastlines With a Simple and Efficient Multiscale Model

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    Ocean-basin-scale climate variability produces shifts in wave climates and water levels affecting the coastlines of the basin. Here we present a hybrid shoreline change?foredune erosion model (A COupled CrOss-shOre, loNg-shorE, and foreDune evolution model, COCOONED) intended to inform coastal planning and adaptation. COCOONED accounts for coupled longshore and cross-shore processes at different timescales, including sequencing and clustering of storm events, seasonal, interannual, and decadal oscillations by incorporating the effects of integrated varying wave action and water levels for coastal hazard assessment. COCOONED is able to adapt shoreline change rates in response to interactions between longshore transport, cross-shore transport, water level variations, and foredune erosion. COCOONED allows for the spatial and temporal extension of survey data using global data sets of waves and water levels for assessing the behavior of the shoreline at multiple time and spatial scales. As a case study, we train the model in the period 2004?2014 (11 years) with seasonal topographic beach profile surveys from the North Beach Sub-cell (NBSC) of the Columbia River Littoral Cell (Washington, USA).We explore the shoreline response and foredune erosion along 40 km of beach at several timescales during the period 1979?2014 (35 years), revealing an accretional trend producing reorientation of the beach, cross-shore accretional, and erosional periods through time (breathing) and alternating beach rotations that are correlated with climate indices.J. A. A. AntolĆ­nez and F. J. MĆ©ndez acknowledge the support of the Spanish ā€œMinisterio de Economia y Competitividadā€ under Grant BIA2014-59643-R
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