4,787 research outputs found

    More means more? Illusory causation between uncorrelated continuous events

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    Illusions of causality arise when people observe statistically unrelated events and yet form a belief that the events are causally linked. When participants observe a sequence of discrete binary events (e.g., a patient was either administered a treatment or no treatment, and subsequently recovers or does not recover from their illness), the frequency of the putative cause and outcome occurring inflates the illusion of causality. Recently, similar effects have been observed using outcomes of continuous magnitude. Participants are more likely to endorse the causal status of a (completely ineffective) cue if the target outcome (e.g., high magnitude outcomes) occur frequently. Here, we extended these findings by investigating how predictions and causal judgments for a cue of continuous magnitude were affected by the distribution of cue values presented. Participants observed cue values (dose of a fictitious medicine) sourced from either a continuous distribution or from two discrete values, and were followed by outcomes that were either continuous (Experiment 1) or binary in nature (Experiment 2). Our results show that participants were more likely to assume a linear relationship between drug dose and magnitude of recovery when cue dosage were predominantly high than when they were predominantly low

    Copper Catalyst Activation Driven by Photoinduced Electron Transfer: A Prototype Photolatent Click Catalyst

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    International audienceWhile the copper(II) tren ketoprofenate precatalyst 1 is inactive at room temperature in methanol, it is quantitatively and rapidly reduced to its cuprous state upon light irradiation to provide a highly reactive click catalyst. By simply introducing air into the reaction medium the catalysis can be switched off and then switched on again by bubbling argon followed by irradiation

    A Framework to Utilize Shear Strength Properties for Evaluating Rutting Potentials of Unbound Aggregate Materials

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    This paper presents shear strength and permanent deformation trends of four unbound aggregate materials, commonly used for base and subbase layers in the state of North Carolina, USA, studied through repeated load triaxial testing, using the University of Illinois FastCell equipment. A testing and modeling framework has been established to develop a proper permanent deformation prediction model, referred to herein as the UIUC rutting model, with number of load applications. According to the framework, the unbound aggregate shear strength properties are incorporated into the model using the ratio of the applied wheel load shear stress to the mobilized shear strength, i.e., the Shear Stress Ratio (SSR). This requires conducting repeated load permanent deformation tests at SSR values of 0.25, 0.5 and 0.75 to determine the trends in permanent deformation accumulation. The prediction ability of the developed UIUC rutting model is evaluated in this paper for the four materials tested at both an engineered target gradation and source gradations

    Robust effects of predictability across experimental contexts: Evidence from event-related potentials

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    Many experiments have shown that comprehenders can generate predictions about upcoming inputs on the fly, but relatively little is known about whether and how comprehenders' sensitivity to predictability may be modulated by the experimental context. The present study used event-related potentials (ERPs) in two experiments to ask whether changing the overall predictive validity of the stimuli will affect comprehenders' brain responses to predictable as well as unpredictable words by manipulating the filler sentences, which made up 50% of the stimuli in each experiment. Contrary to the prediction that predictable words should be processed more easily and elicit a smaller N400 response in a more prediction-encouraging experimental context, we found that participants' N400 response to predictable as well as unpredictable words was smaller when the overall predictive validity of the stimuli was low (that is, when the filler items were incongruous compared to when they were predictable). Further, even though the use of different filler sentences did modulate comprehenders' ERP and behavioural responses, it did not modulate the effect of target word predictability on participants' ERP responses at all. We take the present findings to suggest that healthy young adults’ brain responses are inherently sensitive to the predictability of the incoming linguistic stimuli, and that this robust sensitivity can be observed regardless of the make-up of the experimental stimuli

    New two-dimensional global longitudinal strain and strain rate imaging for assessment of systemic right ventricular function

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    Objectives: To determine the usefulness of new two-dimensional strain indices, based on speckle tracking imaging, for assessment of systemic right ventricular (RV) function after an atrial switch operation for transposition of the great arteries. Design: Cross-sectional study. Setting: Tertiary paediatric cardiac centre. Methods: 26 patients, mean (SD) age 21.0 (3.6) years at 19.9 (3.2) years after an atrial switch operation, and 27 age-matched controls were studied. Two-dimensional imaging at the four-chamber view was obtained with tracing of the entire RV endocardial border. The RV global longitudinal strain (GLS) and GLS rate were derived using automated software (EchoPAC, GE Medical) and correlated with tissue Doppler-derived RV isovolumic acceleration (IVA), and, in the patient cohort, with cardiac magnetic resonance-derived RV ejection fraction. Results: Intra- and interobserver variability for measurement of GLS, as determined from the mean (SD) of differences in two consecutive results from 20 studies, were 0.06 (1.39)% and 0.24 (1.77)%, respectively. Compared with controls, patients had lower RV GLS (17.1 (1.9)% vs 26.3 (2.9)%, p<0.001), a reduced GLS rate (0.78 (0.11)/s vs 1.33 (0.23)/s, p<0.001), lower RV IVA (1.10 (0.36) m/s 2 vs 1.56 (0.53) m/s 2, p<0.001) and increased RV myocardial performance index (0.52 (0.09) vs 0.38 (0.09), p<0.001). Both RV GLS and GLS rate correlated positively with RV IVA (r = 0.43, p = 0.001 and r = 0.46, p<0.001, respectively), and negatively with RV myocardial performance index (r = -0.65, p<0.001 and r = -0.57, p<0.001, respectively). In patients, the GLS rate correlated positively with RV ejection fraction (r = 0.62, p = 0.001). Conclusions: Two-dimensional RV GLS and GLS rate are new, potentially useful indices for assessment of systemic RV function.published_or_final_versio

    Dense-Graded Aggregate Base Gradation Influencing Rutting Model Predictions

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    This paper presents findings from an ongoing research study at the University of Illinois focused on developing and calibrating an improved permanent deformation model for unbound aggregate materials through laboratory testing and characterization. The project scope included testing sixteen aggregate materials, commonly used in the state of North Carolina for pavement base courses, in the laboratory through monotonic and repeated load triaxial testing. This paper primarily focuses on quantifying effects of aggregate gradation on permanent deformation behavior. To accomplish this, four materials were tested at both: (1) “source gradations,” i.e. original gradations from quarry, and (2) an “engineered gradation,” i.e., standard reference gradation at which aggregate specimens were prepared for testing. Predictive rutting models were developed to consider the influences of shear strength and applied stress states on permanent deformation accumulation. Rutting model parameters obtained from testing aggregate specimen at one gradation could be used to reasonably predict the permanent deformation accumulation in another sample given the shear strength properties did not show notable differences. For specimens corresponding to significantly different amounts and/or plastic nature of fines, the permanent strain levels predicted using one set of model parameters differed significantly from those predicted using another set of model parameters developed for another gradation. Moreover, the effects of gradation on permanent strain accumulation were significantly more pronounced at the higher shear stress ratios (e.g. 0.75), compared to lower shear stress ratios; which is defined as the ratio between the shear stress applied to a specimen during repeated load triaxial testing compared to the corresponding shear strength under the same confinement

    The complete primary structure of abrin-a B chain

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    AbstractThe complete 267 amino acid sequence of abrin-a B chain was determined by analysis of peptides obtained by digestion with trypsin, chymotrypsin, lysyl endopeptidase, Staphylacaccus aureus V8 protease and thermolysin. The sequence is not identical with that predicted previously by nucleotide sequencing, indicating the presence of isoforms of abrin. Comparison of the amino acid sequence of abrin-a B chain with that of ricin-D B chain reveals a high degree of sequence identity (59%). Abrin-a B chain appears to consist of two domains, each domain with subdomains (α, β, γ) of about 40 amino acid residues

    Towards a better similarity measure for keyword profiling via clustering

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    Automatic profiling for users and postings can help law enforcement units cluster and classify users and postings effectively so that potential problematic users and postings can be identified easily. A core problem in this application is to come up with effective profiles and a good measure to compare the similarity of two profiles. In this paper, we investigate an existing keyword-based user profiling scheme and identify its limitations. Then, we propose an improved version of it and demonstrate that our proposed version is more consistent than the existing approach with respect to the observed replied rates of a user to a posting based on the similarity of the profiles. © 2013 IEEE.published_or_final_versio

    Incarcerated Vaginal Pessary: A Rare Complication

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    SummaryObjectiveA patient with uterine prolapse (procidentia uteri) received a vaginal pessary, which became incarcerated in the vaginal wall.Case ReportA 70-year-old female patient had been treated for uterine prolapse by insertion of a ring-shaped silicone pessary for about 3 to 4 years. The patient neglected the pessary, which unfortunately became incarcerated in the vaginal wall; it was impossible to remove. Finally, the pessary was displaced after cutting it into two pieces under general anesthesia.ConclusionAfter having inserted a vaginal pessary, patients need to be instructed on its regular removal and cleaning to prevent complications such as infection, ulceration, and incarceration

    A fourth-order Runge-Kutta in the interaction picture method for coupled nonlinear Schrodinger equation

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    A fourth-order Runge-Kutta in the interaction picture (RK4IP) method is presented for solving the coupled nonlinear Schrodinger equation (CNLSE) that governs the light propagation in optical fibers with randomly varying birefringence. The computational error of RK4IP is caused by the fourth-order Runge-Kutta algorithm, better than the split-step approximation limited by the step size. As a result, the step size of RK4IP can have the same order of magnitude as the dispersion length and/or the nonlinear length of the fiber, provided the birefringence effect is small. For communication fibers with random birefringence, the step size of RK4IP can be orders of magnitude larger than the correlation length and the beating length of the fibers, depending on the interaction between linear and nonlinear effects. Our approach can be applied to the fibers having the general form of local birefringence and treat the Kerr nonlinearity without approximation. For the systems with realistic parameters, the RK4IP results are consistent with those using Manakov-PMD approximation. However, increased interaction between the linear and nonlinear terms in CNLSE leads to increased discrepancy between RK4IP and Manakov-PMD approximation.Comment: 12 pages, 4 figures, 1 Table, submitted to Optics Express
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