205 research outputs found

    Information-theoretic equilibration: the appearance of irreversibility under complex quantum dynamics

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    The question of how irreversibility can emerge as a generic phenomena when the underlying mechanical theory is reversible has been a long-standing fundamental problem for both classical and quantum mechanics. We describe a mechanism for the appearance of irreversibility that applies to coherent, isolated systems in a pure quantum state. This equilibration mechanism requires only an assumption of sufficiently complex internal dynamics and natural information-theoretic constraints arising from the infeasibility of collecting an astronomical amount of measurement data. Remarkably, we are able to prove that irreversibility can be understood as typical without assuming decoherence or restricting to coarse-grained observables, and hence occurs under distinct conditions and time-scales than those implied by the usual decoherence point of view. We illustrate the effect numerically in several model systems and prove that the effect is typical under the standard random-matrix conjecture for complex quantum systems.Comment: 15 pages, 7 figures. Discussion has been clarified and additional numerical evidence for information theoretic equilibration is provided for a variant of the Heisenberg model as well as one and two-dimensional random local Hamiltonian

    Disability Rights as a Necessary Framework for Crisis Standards of Care and the Future of Health Care

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    In this essay, we suggest practical ways to shift the framing of crisis standards of care toward disability justice. We elaborate on the vision statement provided in the 2010 Institute of Medicine (National Academy of Medicine) “Summary of Guidance for Establishing Crisis Standards of Care for Use in Disaster Situations,” which emphasizes fairness; equitable processes; community and provider engagement, education, and communication; and the rule of law. We argue that interpreting these elements through disability justice entails a commitment to both distributive and recognitive justice. The disability rights movement\u27s demand “Nothing about us, without us” requires substantive inclusion of disabled people in decision-making related to their interests, including in crisis planning before, during, and after a pandemic like Covid-19

    Geometry of jet spaces and integrable systems

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    An overview of some recent results on the geometry of partial differential equations in application to integrable systems is given. Lagrangian and Hamiltonian formalism both in the free case (on the space of infinite jets) and with constraints (on a PDE) are discussed. Analogs of tangent and cotangent bundles to a differential equation are introduced and the variational Schouten bracket is defined. General theoretical constructions are illustrated by a series of examples.Comment: 54 pages; v2-v6 : minor correction

    Design of Experiments for Screening

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    The aim of this paper is to review methods of designing screening experiments, ranging from designs originally developed for physical experiments to those especially tailored to experiments on numerical models. The strengths and weaknesses of the various designs for screening variables in numerical models are discussed. First, classes of factorial designs for experiments to estimate main effects and interactions through a linear statistical model are described, specifically regular and nonregular fractional factorial designs, supersaturated designs and systematic fractional replicate designs. Generic issues of aliasing, bias and cancellation of factorial effects are discussed. Second, group screening experiments are considered including factorial group screening and sequential bifurcation. Third, random sampling plans are discussed including Latin hypercube sampling and sampling plans to estimate elementary effects. Fourth, a variety of modelling methods commonly employed with screening designs are briefly described. Finally, a novel study demonstrates six screening methods on two frequently-used exemplars, and their performances are compared

    Disability Rights as a Necessary Framework for Crisis Standards of Care and the Future of Health Care

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    In this essay, we suggest practical ways to shift the framing of crisis standards of care toward disability justice. We elaborate on the vision statement provided in the 2010 Institute of Medicine (National Academy of Medicine) “Summary of Guidance for Establishing Crisis Standards of Care for Use in Disaster Situations,” which emphasizes fairness; equitable processes; community and provider engagement, education, and communication; and the rule of law. We argue that interpreting these elements through disability justice entails a commitment to both distributive and recognitive justice. The disability rights movement's demand “Nothing about us, without us” requires substantive inclusion of disabled people in decision-making related to their interests, including in crisis planning before, during, and after a pandemic like Covid-19

    Racial/ethnic variation in EBV-positive classical Hodgkin lymphoma in California populations

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    Epstein-Barr virus (EBV) is detected in the tumor cells of some but not all Hodgkin lymphoma (HL) patients, and evidence indicates that EBV-positive and –negative HL are distinct entities. Racial/ethnic variation in EBV-positive HL in international comparisons suggests etiologic roles for environmental and genetic factors, but these studies used clinical series and evaluated EBV presence by differing protocols. Therefore, we evaluated EBV presence in the tumors of a large (n=1,032), racially and sociodemographically diverse series of California incident classical HL cases with uniform pathology re-review and EBV detection methods. Tumor EBV-positivity was associated with Hispanic and Asian/Pacific Islander (API) but not black race/ethnicity, irrespective of demographic and clinical factors. Complex race-specific associations were observed between EBV-positive HL and age, sex, histology, stage, neighborhood socioeconomic status (SES), and birth place. In Hispanics, EBV-positive HL was associated not only with young and older age, male sex, and mixed cellularity histology, but also with foreign birth and lower SES in females, suggesting immune function responses to correlates of early childhood experience and later environmental exposures, respectively, as well as of pregnancy. For APIs, a lack of association with birth place may reflect the higher SES of API than Hispanic immigrants. In blacks, EBV-positive HL was associated with later-stage disease, consistent with racial/ethnic variation in certain cytokine polymorphisms. The racial/ethnic variation in our findings suggests that EBV-positive HL results from an intricate interplay of early- and later-life environmental, hormonal, and genetic factors leading to depressed immune function and poorly controlled EBV infection

    100 Years of Scientific Evolution of Work and Organizational Psychology: A Bibliometric Network Analysis From 1919 to 2019

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    In this study, we explore a 100 years of Work and Organizational Psychology (WOP). To do this, we carry out a bibliometric performance and network analysis (BPNA) to understand the evolution structure and the most important themes in the field of study. To perform the BNPA, 8,966 documents published since 1919 were exported from the Web of Science and Scopus databases. The SciMAT software was used to process data and to create the evolution structure, the strategic diagram, and the thematic network structure of the strategic themes of the field of WOP. We identified 29 strategic clusters and discuss the most important themes (motor themes) and their relationship with other clusters. This research presents the complete evolution of the field of study, identifying emerging themes and others with a high degree of development. We hope that this work will support researchers and future research in the field of WOP

    A novel lung disease phenotype adjusted for mortality attrition for cystic fibrosis Genetic modifier studies

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    Genetic studies of lung disease in Cystic Fibrosis are hampered by the lack of a severity measure that accounts for chronic disease progression and mortality attrition. Further, combining analyses across studies requires common phenotypes that are robust to study design and patient ascertainment

    Effect of Age on Variability in the Production of Text-Based Global Inferences

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    As we age, our differences in cognitive skills become more visible, an effect especially true for memory and problem solving skills (i.e., fluid intelligence). However, by contrast with fluid intelligence, few studies have examined variability in measures that rely on one’s world knowledge (i.e., crystallized intelligence). The current study investigated whether age increased the variability in text based global inference generation–a measure of crystallized intelligence. Global inference generation requires the integration of textual information and world knowledge and can be expressed as a gist or lesson. Variability in generating two global inferences for a single text was examined in young-old (62 to 69 years), middle-old (70 to 76 years) and old-old (77 to 94 years) adults. The older two groups showed greater variability, with the middle elderly group being most variable. These findings suggest that variability may be a characteristic of both fluid and crystallized intelligence in aging
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