2,637 research outputs found

    For the sake of future generations : intergenerational justice and climate change mitigation

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    [Introductory paragraph] The present generation must confront a challenge. The challenge is to determine what it must do for the sake of future generations. This challenge is quite puzzling because the present generation, like its predecessors, will pass on to future generations a complex mix of goods, inventions, institutions and opportunities containing a range of benefits and burdens. In this thesis, I focus on one key intergenerational problem – anthropogenic climate change – considering some of the questions of intergenerational justice that it raises. While it has not always been the case, climate and climate change have recently taken on new significance as a process to which humans can, and in fact do, contribute. More specifically, while paleoclimatic data show substantial variation in the Earth’s climate (Masson- Delmotte, Schulz, Abe-Ouchi, Beer, Ganopolski, J.F. González Rouco, E. Jansen, et al., 2013: 385), an ever-growing mass of evidence shows that human activity – particularly the sustained emission of greenhouse gases (GHGs) – is beginning to change the global climate, with much greater changes still to come (IPCC, 2013b: 4, 19ff). This produces what is known as anthropogenic climate change, “a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer”, and that results from human activities (IPCC, 2013a: 1448, 1450)

    Parallel-propagating Fluctuations at Proton-kinetic Scales in the Solar Wind are Dominated by Kinetic Instabilities

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    We use magnetic helicity to characterise solar wind fluctuations at proton-kinetic scales from Wind observations. For the first time, we separate the contributions to helicity from fluctuations propagating at angles quasi-parallel and oblique to the local mean magnetic field, B0\mathbf{B}_0. We find that the helicity of quasi-parallel fluctuations is consistent with Alfv\'en-ion cyclotron and fast magnetosonic-whistler modes driven by proton temperature anisotropy instabilities and the presence of a relative drift between α\alpha-particles and protons. We also find that the helicity of oblique fluctuations has little dependence on proton temperature anisotropy and is consistent with fluctuations from the anisotropic turbulent cascade. Our results show that parallel-propagating fluctuations at proton-kinetic scales in the solar wind are dominated by proton temperature anisotropy instabilities and not the turbulent cascade. We also provide evidence that the behaviour of fluctuations at these scales is independent of the origin and macroscopic properties of the solar wind.Comment: Accepted for publication in ApJL. 6 Pages, 3 figures, 1 tabl

    The National COVID Cohort Collaborative: Clinical Characterization and Early Severity Prediction [preprint]

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    Background: The majority of U.S. reports of COVID-19 clinical characteristics, disease course, and treatments are from single health systems or focused on one domain. Here we report the creation of the National COVID Cohort Collaborative (N3C), a centralized, harmonized, high-granularity electronic health record repository that is the largest, most representative U.S. cohort of COVID-19 cases and controls to date. This multi-center dataset supports robust evidence-based development of predictive and diagnostic tools and informs critical care and policy. Methods and Findings: In a retrospective cohort study of 1,926,526 patients from 34 medical centers nationwide, we stratified patients using a World Health Organization COVID-19 severity scale and demographics; we then evaluated differences between groups over time using multivariable logistic regression. We established vital signs and laboratory values among COVID-19 patients with different severities, providing the foundation for predictive analytics. The cohort included 174,568 adults with severe acute respiratory syndrome associated with SARS-CoV-2 (PCR \u3e99% or antigen Conclusions: This is the first description of an ongoing longitudinal observational study of patients seen in diverse clinical settings and geographical regions and is the largest COVID-19 cohort in the United States. Such data are the foundation for ML models that can be the basis for generalizable clinical decision support tools. The N3C Data Enclave is unique in providing transparent, reproducible, easily shared, versioned, and fully auditable data and analytic provenance for national-scale patient-level EHR data. The N3C is built for intensive ML analyses by academic, industry, and citizen scientists internationally. Many observational correlations can inform trial designs and care guidelines for this new disease

    The Relationship between Military Combat and Cardiovascular Risk: A Systematic Review and Meta-Analysis

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    © 2019 Christopher J. Boos et al. Background and Objectives. Cardiovascular disease (CVD) is a leading cause of death among military veterans with several reports suggesting a link between combat and related traumatic injury (TI) to an increased CVD risk. The aim of this paper is to conduct a widespread systematic review and meta-analysis of the relationship between military combat ± TI to CVD and its associated risk factors. Methods. PubMed, EmbaseProQuest, Cinahl databases and Cochrane Reviews were examined for all published observational studies (any language) reporting on CVD risk and outcomes, following military combat exposure ± TI versus a comparative nonexposed control population. Two investigators independently extracted data. Data quality was rated and rated using the 20-item AXIS Critical Appraisal Tool. The risk of bias (ROB using the ROBANS 6 item tool) and strength of evidence (SOE) were also critically appraised. Results. From 4499 citations, 26 studies (14 cross sectional and 12 cohort; 78-100% male) met the inclusion criteria. The follow up period ranged from 1 to 43.6 years with a sample size ranging from 19 to 621901 participants in the combat group. Combat-related TI was associated with a significantly increased risk for CVD (RR 1.80: 95% CI 1.24-2.62; I 2 = 59 %, p = 0.002) and coronary heart disease (CHD)-related death (risk ratio 1.57: 95% CI 1.35-1.83; I 2 = 0 %, p = 0.77: p < 0.0001), although the SOE was low. Military combat (without TI) was linked to a marginal, yet significantly lower pooled risk (low SOE) of cardiovascular death in the active combat versus control population (RR 0.90: CI 0.83-0.98; I 2 = 47 %, p = 0.02). There was insufficient evidence linking combat ± TI to any other cardiovascular outcomes or risk factors. Conclusion. There is low SOE to support a link between combat-related TI and both cardiovascular and CHD-related mortality. There is insufficient evidence to support a positive association between military combat ± any other adverse cardiovascular outcomes or risk factors. Data from well conducted prospective cohort studies following combat are needed

    Optimal Universal and State-Dependent Quantum Cloning

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    We establish the best possible approximation to a perfect quantum cloning machine which produces two clones out of a single input. We analyze both universal and state-dependent cloners. The maximal fidelity of cloning is shown to be 5/6 for universal cloners. It can be achieved either by a special unitary evolution or by a novel teleportation scheme. We construct the optimal state-dependent cloners operating on any prescribed two non-orthogonal states, discuss their fidelities and the use of auxiliary physical resources in the process of cloning. The optimal universal cloners permit us to derive a new upper bound on the quantum capacity of the depolarizing quantum channel.Comment: 30 pages (RevTeX), 2 figures (epsf), further results and further authors added, to appear in Physical Review

    Chow diet in mouse aging studies: nothing regular about it.

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    Chow diet is used in the majority of rodent studies and, although assumed to be standardized for dietary source and nutritional contents, it varies widely across commercial formulations. Similarly, current approaches to study aging in rodents involve a single-diet formulation across the lifespan and overlook age-specific nutritional requirements, which may have long-term effects on aging processes. Together, these nutrition-based disparities represent major gaps in geroscience research, affecting the interpretation and reproducibility of the studies. This perspective aims to raise awareness on the importance of rodent diet formulation and proposes that geroscientists include detailed descriptions of all experimental diets and feeding protocols. Detailed reporting of diets will enhance rigor and reproducibility of aging rodent studies and lead to more translational outcomes in geroscience research

    The political economy of management knowledge : management texts in English healthcare organizations

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    Have generic management texts and associated knowledges now extensively diffused into public services organizations? If so, why? Our empirical study of English healthcare organizations detects an extensive presence of such texts. We argue that their ready diffusion relates to two macro-level forces: (i) the influence of the underlying political economy of public services reform and (ii) a strongly developed business school/management consulting knowledge nexus. This macro perspective theoretically complements existing explanations from the meso or middle level of analysis which examine diffusion processes within the public services field, and also more micro literature which focuses on agency from individual knowledge leaders

    Equity trade-offs in conservation decision making

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    Conservation decisions increasingly involve multiple environmental and social objectives, which result in complex decision contexts with high potential for trade-offs. Improving social equity is one such objective that is often considered an enabler of successful outcomes and a virtuous ideal in itself. Despite its idealized importance in conservation policy, social equity is often highly simplified or ill-defined and is applied uncritically. What constitutes equitable outcomes and processes is highly normative and subject to ethical deliberation. Different ethical frameworks may lead to different conceptions of equity through alternative perspectives of what is good or right. This can lead to different and potentially conflicting equity objectives in practice. We promote a more transparent, nuanced, and pluralistic conceptualization of equity in conservation decision making that particularly recognizes where multidimensional equity objectives may conflict. To help identify and mitigate ethical conflicts and avoid cases of good intentions producing bad outcomes, we encourage a more analytical incorporation of equity into conservation decision making particularly during mechanistic integration of equity objectives. We recommend that in conservation planning motivations and objectives for equity be made explicit within the problem context, methods used to incorporate equity objectives be applied with respect to stated objectives, and, should objectives dictate, evaluation of equity outcomes and adaptation of strategies be employed during policy implementation

    Quantum probabilities as Bayesian probabilities

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    In the Bayesian approach to probability theory, probability quantifies a degree of belief for a single trial, without any a priori connection to limiting frequencies. In this paper we show that, despite being prescribed by a fundamental law, probabilities for individual quantum systems can be understood within the Bayesian approach. We argue that the distinction between classical and quantum probabilities lies not in their definition, but in the nature of the information they encode. In the classical world, maximal information about a physical system is complete in the sense of providing definite answers for all possible questions that can be asked of the system. In the quantum world, maximal information is not complete and cannot be completed. Using this distinction, we show that any Bayesian probability assignment in quantum mechanics must have the form of the quantum probability rule, that maximal information about a quantum system leads to a unique quantum-state assignment, and that quantum theory provides a stronger connection between probability and measured frequency than can be justified classically. Finally we give a Bayesian formulation of quantum-state tomography.Comment: 6 pages, Latex, final versio
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