852 research outputs found

    Estimating the burden of COVID-19 on mortality, life expectancy and lifespan inequality in England and Wales : a population-level study

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    Objective: To determine the impact of the COVID-19 pandemic on mortality, life expectancy and lifespan inequality in the first half of 2020 (from week 1 to week 26 starting June 22) in England and Wales. Design: Demographic analysis of all-cause mortality from week 1 through week 26 of 2020 using publicly available death registration data from the Office for National Statistics. Setting and population: England and Wales population by age and sex in 2020. Main outcome measure: Age and sex-specific excess mortality risk and deaths above a baseline adjusted for seasonality in the first half of 2020. We additionally provide estimates of life expectancy at birth and lifespan inequality defined as the standard deviation in age at death. Results: We estimate that there have been 53,937 (95% Prediction Interval: 53,092, 54,746) excess deaths in the first half of 2020, 54% of which occurred in men. Excess deaths increased sharply with age and men experienced elevated risks of death in all age groups. Life expectancy at birth dropped 1.7 and 1.9 years for females and males relative to the 2019 levels, respectively. Lifespan inequality also fell over the same period. Conclusions: Quantifying excess deaths and their impact on life expectancy at birth provides a more comprehensive picture of the full COVID-19 burden on mortality. Whether mortality will return to - or even fall below - the baseline level remains to be seen as the pandemic continues to unfold and diverse interventions are put in place

    Biogeographic multi‐species occupancy models for large‐scale survey data

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    Ecologists often seek to infer patterns of species occurrence or community structure from survey data. Hierarchical models, including multi-species occupancy models (MSOMs), can improve inference by pooling information across multiple species via random effects. Originally developed for local-scale survey data, MSOMs are increasingly applied to larger spatial scales that transcend major abiotic gradients and dispersal barriers. At biogeographic scales, the benefits of partial pooling in MSOMs trade off against the difficulty of incorporating sufficiently complex spatial effects to account for biogeographic variation in occupancy across multiple species simultaneously. We show how this challenge can be overcome by incorporating preexisting range information into MSOMs, yielding a “biogeographic multi-species occupancy model” (bMSOM). We illustrate the bMSOM using two published datasets: Parulid warblers in the United States Breeding Bird Survey and entire avian communities in forests and pastures of Colombia's West Andes. Compared with traditional MSOMs, the bMSOM provides dramatically better predictive performance at lower computational cost. The bMSOM avoids severe spatial biases in predictions of the traditional MSOM and provides principled species-specific inference even for never-observed species. Incorporating preexisting range data enables principled partial pooling of information across species in large-scale MSOMs. Our biogeographic framework for multi-species modeling should be broadly applicable in hierarchical models that predict species occurrences, whether or not false absences are modeled in an occupancy framework

    Current residual based stator inter-turn fault detection in permanent magnet machines

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    Inter-turn short circuit fault, also known as turn fault is a common fault in electric machines which can cause severe damages if no prompt detection and mitigation are conducted. This paper proposes a turn fault detection method for permanent magnet machines based on current residual. After the impact of the turn fault is firstly analyzed on a simplified mathematical machine model to assess the fault signature, a finite element (FE) model is developed to obtain healthy machine behavior. The residual between the measured and estimated currents by the model with the same applied voltages contains mainly the fault features. The quality of the fault detection can be improved because the fault signatures are enhanced, and the impact of the current controller bandwidth on fault signature is minimized. The dc components in the negative sequence current residuals are extracted through angular integration and their magnitude is defined as the fault indicator. The robustness of the fault detection against transient states is achieved. The effectiveness of the proposed method is validated on a triple redundant fault tolerant permanent magnet assisted synchronous reluctance machine (PMA SynRM)

    Estimating the burden of the COVID-19 pandemic on mortality, life expectancy and lifespan inequality in England and Wales: a population-level analysis

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    Background Deaths directly linked to COVID-19 infection may be misclassified, and the pandemic may have indirectly affected other causes of death. To overcome these measurement challenges, we estimate the impact of the COVID-19 pandemic on mortality, life expectancy and lifespan inequality from week 10 of 2020, when the first COVID-19 death was registered, to week 47 ending 20 November 2020 in England and Wales through an analysis of excess mortality. Methods We estimated age and sex-specific excess mortality risk and deaths above a baseline adjusted for seasonality with a systematic comparison of four different models using data from the Office for National Statistics. We additionally provide estimates of life expectancy at birth and lifespan inequality defined as the SD in age at death. Results There have been 57 419 (95% prediction interval: 54 197, 60 752) excess deaths in the first 47 weeks of 2020, 55% of which occurred in men. Excess deaths increased sharply with age and men experienced elevated risks of death in all age groups. Life expectancy at birth dropped 0.9 and 1.2 years for women and men relative to the 2019 levels, respectively. Lifespan inequality also fell over the same period by 5 months for both sexes. Conclusion Quantifying excess deaths and their impact on life expectancy at birth provide a more comprehensive picture of the burden of COVID-19 on mortality. Whether mortality will return to—or even fall below—the baseline level remains to be seen as the pandemic continues to unfold and diverse interventions are put in place

    Socio-demographic and epidemiological consideration of Africa’s COVID-19 response: what is the possible pandemic course?

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    Many predicted a heavy toll of the COVID-19 pandemic on Africa. Its weakened health systems were harbingers of a terrible outcome. However, local expertise gathered from previous outbreaks and centralized public-health infrastructure with a clear action plan, in addition to a favorable demographic structure and climate, have put many countries in the continent in good standing to face this epidemic head on

    Noise and Fluctuations in Semiclassical Gravity

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    We continue our earlier investigation of the backreaction problem in semiclassical gravity with the Schwinger-Keldysh or closed-time-path (CTP) functional formalism using the language of the decoherent history formulation of quantum mechanics. Making use of its intimate relation with the Feynman-Vernon influence functional (IF) method, we examine the statistical mechanical meaning and show the interrelation of the many quantum processes involved in the backreaction problem, such as particle creation, decoherence and dissipation. We show how noise and fluctuation arise naturally from the CTP formalism. We derive an expression for the CTP effective action in terms of the Bogolubov coefficients and show how noise is related to the fluctuations in the number of particles created. In so doing we have extended the old framework of semiclassical gravity, based on the mean field theory of Einstein equation with a source given by the expectation value of the energy-momentum tensor, to that based on a Langevin-type equation, where the dynamics of fluctuations of spacetime is driven by the quantum fluctuations of the matter field. This generalized framework is useful for the investigation of quantum processes in the early universe involving fluctuations, vacuum stability and phase transtion phenomena and the non-equilibrium thermodynamics of black holes. It is also essential to an understanding of the transition from any quantum theory of gravity to classical general relativity. \pacs{pacs numbers: 04.60.+n,98.80.Cq,05.40.+j,03.65.Sq}Comment: Latex 37 pages, umdpp 93-216 (submitted to Phys. Rev. D, 24 Nov. 1993

    Star Formation and Dynamics in the Galactic Centre

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    The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A., 'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201

    Reproduction and transformation of inequalities in schooling: The transformative potential of the theoretical constructs of Bourdieu

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    This article is concerned with the theoretical constructs of Bourdieu and their contribution to understanding the reproduction of social and cultural inequalities in schooling. While Bourdieu has been criticised for his reproductive emphasis, this article proposes that there is transformative potential in his theoretical constructs and that these suggest possibilities for schools and teachers to improve the educational outcomes of marginalised students. The article draws together three areas of contribution to this theme of transformation; beginning by characterising habitus as constituted by reproductive and transformative traits and considering the possibilities for the restructuring of students’ habitus. This is followed by a discussion of cultural capital and the way that teachers can draw upon a variety of cultural capitals to act as agents of transformation rather than reproduction. The article concludes by considering the necessity of a transformation of the field to improve the educational outcomes of marginalised students
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