9,586 research outputs found

    Dual-moods and creativity in organisation: A bidirectional mood regulation perspective

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    The mixed impacts of mood states on creativity call for reconciliation. Contrary to the prevailing notion that positive moods foster creativity, an emerging body of research suggests that negative moods can also boost creativity, and even that positive moods may impair creativity. More recent research suggests that the dual-moods, instead of singular positive or negative moods, can jointly foster creativity, opening a new avenue for mood-creativity research. Nevertheless, the current research which focuses on static mood states is still inadequate to explain the dynamic impacts of moods on creativity over time. To answer this question, we propose that a bidirectional moodregulatory process can reconcile the mixed impacts of dual-moods on creativity with respect to mood changes, and discuss possible research approaches

    Quadratic Word Equations with Length Constraints, Counter Systems, and Presburger Arithmetic with Divisibility

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    Word equations are a crucial element in the theoretical foundation of constraint solving over strings, which have received a lot of attention in recent years. A word equation relates two words over string variables and constants. Its solution amounts to a function mapping variables to constant strings that equate the left and right hand sides of the equation. While the problem of solving word equations is decidable, the decidability of the problem of solving a word equation with a length constraint (i.e., a constraint relating the lengths of words in the word equation) has remained a long-standing open problem. In this paper, we focus on the subclass of quadratic word equations, i.e., in which each variable occurs at most twice. We first show that the length abstractions of solutions to quadratic word equations are in general not Presburger-definable. We then describe a class of counter systems with Presburger transition relations which capture the length abstraction of a quadratic word equation with regular constraints. We provide an encoding of the effect of a simple loop of the counter systems in the theory of existential Presburger Arithmetic with divisibility (PAD). Since PAD is decidable, we get a decision procedure for quadratic words equations with length constraints for which the associated counter system is \emph{flat} (i.e., all nodes belong to at most one cycle). We show a decidability result (in fact, also an NP algorithm with a PAD oracle) for a recently proposed NP-complete fragment of word equations called regular-oriented word equations, together with length constraints. Decidability holds when the constraints are additionally extended with regular constraints with a 1-weak control structure.Comment: 18 page

    Spin Structures on Kleinian Manifolds

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    We derive the topological obstruction to spin-Klein cobordism. This result has implications for signature change in general relativity, and for the N=2N=2 superstring.Comment: 8 page

    Judgments of learning and improvement

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    Can learners accurately judge the rate of their learning? Rates of learning may be informative when study time is allocated across materials, and students' judgments of their learning rate have been proposed as a possible metacognitive tool. Participants estimated how much they improved between presentations in multitrial learning situations in which n-gram paragraphs (in Experiments 1 and 2) or word pairs (Experiments 3 and 4) were learned . In the first experiment, participants rated improvement on a percentage scale, whereas on the second and third, judgments were given on a 0–6 scale. Experiment 4 used both a percentage scale and an absolute number scale. The main result was that judgments of improvement were poorly correlated with actual improvement and, in one case, were negatively correlated. Although judgments of improvement were correlated with changes in judgments of learning, they were not reliable indicators of actual improvement. Implications are discussed for theoretical work on metacognition

    A FRET analysis to unravel the role of cholesterol in Rac1 and PI 3-kinase activation in the InlB/Met signalling pathway

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    The signalling pathway for the hepatocyte growth factor receptor, Met/HGF-R, is hijacked by the bacterial surface protein InlB to induce Listeria monocytogenes entry into non-phagocytic cells. We previously showed that Listeria invades host cells by interacting with specialized microdomains of the host plasma membrane called lipid rafts. In this study, we analysed in living cells signalling events that are crucial for Listeria entry using a fluorescence resonance energy transfer-based microscopic method. Phosphoinositide (PI) 3-kinase activity and Rac1 signalling induced by Listeria interacting with epithelial cells were monitored as well as signalling induced by soluble InlB and the Met natural ligand HGF. We found that InlB and HGF induced similar kinetics of PI 3-kinase and Rac1 activation. PI 3-kinase activation was upstream and independent of Rac1 activation. Cholesterol-depletion experiments were performed to address the role of lipid rafts in Met signalling. The amount of 3â€Č-phosphoinositides produced by PI 3-kinase was not affected by cholesterol depletion, while their membrane dynamic was cholesterol-dependent. Rac1 activation, downstream from PI 3-kinase, was cholesterol-dependent suggesting that the spatial distribution of 3â€Č-phosphoinositides within membrane microdomains is critical for Rac1 activation and consequently for F-actin assembly at bacterial entry site.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74959/1/j.1462-5822.2006.00832.x.pd

    One Loop Renormalizability of Spontaneously Broken Gauge Theory with a Product of Gauge Groups on Noncommutative Spacetime: the U(1) x U(1) Case

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    A generalization of the standard electroweak model to noncommutative spacetime would involve a product gauge group which is spontaneously broken. Gauge interactions in terms of physical gauge bosons are canonical with respect to massless gauge bosons as required by the exact gauge symmetry, but not so with respect to massive ones; and furthermore they are generally asymmetric in the two sets of gauge bosons. On noncommutative spacetime this already occurs for the simplest model of U(1) x U(1). We examine whether the above feature in gauge interactions can be perturbatively maintained in this model. We show by a complete one loop analysis that all ultraviolet divergences are removable with a few renormalization constants in a way consistent with the above structure.Comment: 24 pages, figures using axodraw; version 2: a new ref item [4] added to cite efforts to all orders, typos fixed and minor rewordin

    Modelling CDA mass spectra

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    We present the initial results from a simulation of ion behaviour within Cassini's cosmic dust analyser (CDA) instrument, using an in-house ion dynamics code. This work is to enable and enhance the detailed interpretation of dust impact ionisation mass spectra returned from the Saturnian system. Early work has already provided insights into the properties of the impact plasma in both low- and high-velocity impacts. We find that the isotropic emission of ions from the impact plasma successfully reproduces features seen in flight spectra and that the emitted ions have a higher range of energies (tens to hundreds of eV) than previously reported in some studies. Using these new ion characteristics, we have successfully modelled CDA flight mass spectra

    Time-to-birth prediction models and the influence of expert opinions

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    Preterm birth is the leading cause of death among children under five years old. The pathophysiology and etiology of preterm labor are not yet fully understood. This causes a large number of unnecessary hospitalizations due to high--sensitivity clinical policies, which has a significant psychological and economic impact. In this study, we present a predictive model, based on a new dataset containing information of 1,243 admissions, that predicts whether a patient will give birth within a given time after admission. Such a model could provide support in the clinical decision-making process. Predictions for birth within 48 h or 7 days after admission yield an Area Under the Curve of the Receiver Operating Characteristic (AUC) of 0.72 for both tasks. Furthermore, we show that by incorporating predictions made by experts at admission, which introduces a potential bias, the prediction effectiveness increases to an AUC score of 0.83 and 0.81 for these respective tasks

    Clinical significance of hepatic derangement in severe acute respiratory syndrome

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    Aim: Elevation of alanine aminotransferase (ALT) level is commonly seen among patients suffering from severe acute respiratory syndrome (SARS). We report the progression and clinical significance of liver derangement in a large cohort of SARS patient. Methods: Serial assay of serum ALT was followed in patients who fulfilled the WHO criteria of SARS. Those with elevated ALT were compared with those with normal liver functions for clinical outcome. Serology for hepatitis B virus (HBV) infection was checked. Adverse outcomes were defined as oxygen desaturation, need of intensive care unit (ICU) and mechanical ventilation and death. Results: Two hundred and ninety-four patients were included in this study. Seventy (24%) patients had elevated serum ALT on admission and 204 (69%) patients had elevated ALT during the subsequent course of illness. Using peak ALT >5×ULN as a cut-off and after adjusting for potential confounding factors, the odds ratio of peak ALT >5× ULN for oxygen desaturation was 3.24 (95%CI 1.23-8.59, P = 0.018), ICU care was 3.70 (95%CI 1.38-9.89, P = 0.009), mechanical ventilation was 6.64 (95%CI 2.22-19.81, P = 0.001) and death was 7.34 (95%CI 2.28-24.89, P = 0.001). Ninety-three percent of the survived patients had ALT levels normalized or were on the improving trend during follow-up. Chronic hepatitis B was not associated with worse clinical outcomes. Conclusion: Reactive hepatitis is a common complication of SARS-coronavirus infection. Those patients with severe hepatitis had worse clinical outcome. © 2005 The WJG Press and Elsevier Inc. All rights reserved.published_or_final_versio

    E_{11}, ten forms and supergravity

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    We extend the previously given non-linear realisation of E_{11} for the decomposition appropriate to IIB supergravity to include the ten forms that were known to be present in the adjoint representation. We find precise agreement with the results on ten forms found by closing the IIB supersymmetry algebra.Comment: 14 page
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