103 research outputs found

    Self-Referential Noise as a Fundamental Aspect of Reality

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    Noise is often used in the study of open systems, such as in classical Brownian motion and in Quantum Dynamics, to model the influence of the environment. However generalising results from G\"{o}del and Chaitin in mathematics suggests that systems that are sufficiently rich that self-referencing is possible contain intrinsic randomness. We argue that this is relevant to modelling the universe, even though it is by definition a closed system. We show how a three-dimensional process-space may arise, as a Prigogine dissipative structure, from a non-geometric order-disorder model driven by, what is termed, self-referential noise.Comment: 7 pages, Latex, 3 ps figures. Contribution to the 2nd International Conference on Unsolved Problems of Noise, Adelaide 199

    Providing study skills advice to the math-anxious: developing a model for effective teaching practice

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    This paper is the result of a pilot study to motivate and help structure the development of a model for effective teaching practice when providing academic assistance to math-anxious university students. Students seeking academic skills advice for math-related study problems are identified within two broad categories, one of which contains a sub-category of students who are at most risk of academic failure or withdrawal. A range of issues is considered via a literature review and examination of actual case notes and summary data. A client student profile is identified and the learner/teacher styles and interaction are reported. Finally, "numerosity", numeracy, and the connections between language and math anxiety are briefly discussed

    Self-Referential Noise and the Synthesis of Three-Dimensional Space

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    Generalising results from Godel and Chaitin in mathematics suggests that self-referential systems contain intrinsic randomness. We argue that this is relevant to modelling the universe and show how three-dimensional space may arise from a non-geometric order-disorder model driven by self-referential noise.Comment: Figure labels correcte

    Randomized Trial of Tenecteplase or Placebo with Low Molecular Weight Heparin for Acute Submassive Pulmonary Embolism: Assessment of Patient-Oriented Cardiopulmonary Outcomes at Three Months

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    Background: Acute submassive pulmonary embolism (PE) with right ventricular (RV) injury and/or concomitant deep venous thrombosis can cause persistent symptoms that degrade quality of life. We tested the hypothesis that intravenous tenecteplase would improve the probability of a favorable outcome at three months after submassive PE. Methods: Multicenter randomized double-blind, placebo controlled trial. Eligible patients were ambulatory at baseline, had image-proven acute PE, a systolic blood pressure > 90 mm Hg and RV dysfunction (abnormal echocardiography, troponin or brain natriuretic peptide). Patients received anticoagulation with low molecular weight heparin (LMWH) and either tiered-dose tenecteplase or saline in an opaque syringe. Composite favorable outcome: 5 day survival to hospital discharge without shock, intubation, or major hemorrhage (any intracranial bleed or need for surgical or medical intervention for acute anemia), and at 90 days, normal RV on resting echocardiography, 6 minute walk distance>330 m, no dyspnea at rest, and no recurrent PE or DVT. Self-perception of wellness was assessed by the SF-16, VEINES-QOL and rank on 1-10 ordinal scale. Results: 83 patients were enrolled, including 33 women, 52 Caucasians, mean age 55+/-14 years, 43 received placebo, 40 received tenecteplase, and 38 had concomittant DVT. A favorable composite outcome occurred in 17/43(40%, 95% CI: 25-56%) treated with placebo, versus 26/40 (65%, 95% CI: 48-79%) treated with tenecteplase, p=0.02 Fisher’s exact. Acute deterioration occurred in 3 patients treated with placebo: fatal PE (1), intubation (1), thrombectomy (1) and in one patient treated with tenecteplase who had a fatal intracranial hemorrhage. At three months, a nonfavorable outcome was found in 23 additional patients treated with placebo, versus 13 patients treated with tenecteplase. Assessments of wellness were consistently higher in the tenecteplase group (e.g., p=0.03 for ordinal scale rank). Conclusions: In this randomized trial, patients with submassive PE treated with LMWH and tenecteplase were more likely to have a favorable patient-oriented outcome at three months than patients treated with LMWH and saline placebo

    Plastid Transcript Editing across Dinoflagellate Lineages Shows Lineage-Specific Application but Conserved Trends.

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    Dinoflagellates are a group of unicellular protists with immense ecological and evolutionary significance and cell biological diversity. Of the photosynthetic dinoflagellates, the majority possess a plastid containing the pigment peridinin, whereas some lineages have replaced this plastid by serial endosymbiosis with plastids of distinct evolutionary affiliations, including a fucoxanthin pigment-containing plastid of haptophyte origin. Previous studies have described the presence of widespread substitutional RNA editing in peridinin and fucoxanthin plastid genes. Because reports of this process have been limited to manual assessment of individual lineages, global trends concerning this RNA editing and its effect on the biological function of the plastid are largely unknown. Using novel bioinformatic methods, we examine the dynamics and evolution of RNA editing over a large multispecies data set of dinoflagellates, including novel sequence data from the peridinin dinoflagellate Pyrocystis lunula and the fucoxanthin dinoflagellate Karenia mikimotoi. We demonstrate that while most individual RNA editing events in dinoflagellate plastids are restricted to single species, global patterns, and functional consequences of editing are broadly conserved. We find that editing is biased toward specific codon positions and regions of genes, and generally corrects otherwise deleterious changes in the genome prior to translation, though this effect is more prevalent in peridinin than fucoxanthin lineages. Our results support a model for promiscuous editing application subsequently shaped by purifying selection, and suggest the presence of an underlying editing mechanism transferred from the peridinin-containing ancestor into fucoxanthin plastids postendosymbiosis, with remarkably conserved functional consequences in the new lineage

    Progressive and biased divergent evolution underpins the origin and diversification of peridinin dinoflagellate plastids

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    Dinoflagellates are algae of tremendous importance to ecosystems and to public health. The cell biology and genome organization of dinoflagellate species is highly unusual. For example, the plastid genomes of peridinin-containing dinoflagellates encode only a minimal number of genes arranged on small elements termed "minicircles". Previous studies of peridinin plastid genes have found evidence for divergent sequence evolution, including extensive substitutions, novel insertions and deletions, and use of alternative translation initiation codons. Understanding the extent of this divergent evolution has been hampered by the lack of characterized peridinin plastid sequences. We have identified over 300 previously unannotated peridinin plastid mRNAs from published transcriptome projects, vastly increasing the number of sequences available. Using these data, we have produced a well-resolved phylogeny of peridinin plastid lineages, which uncovers several novel relationships within the dinoflagellates. This enables us to define changes to plastid sequences that occurred early in dinoflagellate evolution, and that have contributed to the subsequent diversification of individual dinoflagellate clades. We find that the origin of the peridinin dinoflagellates was specifically accompanied by elevations both in the overall number of substitutions that occurred on plastid sequences, and in the Ka/Ks ratio associated with plastid sequences, consistent with changes in selective pressure. These substitutions, alongside other changes, have accumulated progressively in individual peridinin plastid lineages. Throughout our entire dataset, we identify a persistent bias toward non-synonymous substitutions occurring on sequences encoding photosystem I subunits and stromal regions of peridinin plastid proteins, which may have underpinned the evolution of this unusual organelle.Wellcome Trus

    An integrative study of motivation and goal regulation processes in subclinical anxiety, depression and hypomania

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    Research has implicated motivation and goal regulation in susceptibility to mood disorders. We studied for the first time key facets of motivation and goal regulation concurrently in relation to affective symptoms. The cross-national sample comprised 510 university students from the United States (n = 279) and United Kingdom (n = 231). Participants completed self-report measures of motivation, conditional goal setting, urgency, depression, anxiety, and mania risk. Structural Equation Modeling results found that behavioral activation system scores correlated negatively with depression and positively with mania risk, but were unrelated to anxiety. High conditional goal setting correlated uniquely with higher depression but not to anxiety or mania risk. Urgency correlated with higher anxiety, depression, and mania risk. Behavioral inhibition system scores correlated negatively with mania risk but unexpectedly did not correlate with anxiety in the multivariate model. The behavioral activation, behavioral inhibition, conditional goal setting, and urgency results showed shared and distinct patterns of relationships with depression, anxiety and mania risk. Our findings indicate unique and common risk vulnerabilities in depressive, anxious, and manic syndromes and extend an integrative knowledge of these syndromes in relation to goal regulation

    Prediction Scores Do Not Correlate with Clinically Adjudicated Categories of Pulmonary Embolism in Critically Ill Patients

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    Copyright © 2014 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.BACKGROUND: Prediction scores for pretest probability of pulmonary embolism (PE) validated in outpatient settings are occasionally used in the intensive care unit (ICU).OBJECTIVE: To evaluate the correlation of Geneva and Wells scores with adjudicated categories of PE in ICU patients.METHODS: In a randomized trial of thromboprophylaxis, patients with suspected PE were adjudicated as possible, probable or definite PE. Data were then retrospectively abstracted for the Geneva Diagnostic PE score, Wells, Modified Wells and Simplified Wells Diagnostic scores. The chance-corrected agreement between adjudicated categories and each score was calculated. ANOVA was used to compare values across the three adjudicated PE categories.RESULTS: Among 70 patients with suspected PE, agreement was poor between adjudicated categories and Geneva pretest probabilities (kappa 0.01 [95% CI −0.0643 to 0.0941]) or Wells pretest probabilities (kappa −0.03 [95% CI −0.1462 to 0.0914]). Among four possible, 16 probable and 50 definite PEs, there were no significant differences in Geneva scores (possible = 4.0, probable = 4.7, definite = 4.5; P=0.90), Wells scores (possible = 2.8, probable = 4.9, definite = 4.1; P=0.37), Modified Wells (possible = 2.0, probable = 3.4, definite = 2.9; P=0.34) or Simplified Wells (possible = 1.8, probable = 2.8, definite = 2.4; P=0.30).CONCLUSIONS: Pretest probability scores developed outside the ICU do not correlate with adjudicated PE categories in critically ill patients. Research is needed to develop prediction scores for this population
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