1,603 research outputs found

    Struggling to a monumental triumph : Re-assessing the final stages of the smallpox eradication program in India, 1960-1980

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    The global smallpox program is generally presented as the brainchild of a handful of actors from the WHO headquarters in Geneva and at the agency's regional offices. This article attempts to present a more complex description of the drive to eradicate smallpox. Based on the example of India, a major focus of the campaign, it is argued that historians and public health officials should recognize the varying roles played by a much wider range of participants. Highlighting the significance of both Indian and international field officials, the author shows how bureaucrats and politicians at different levels of administration and society managed to strengthen—yet sometimes weaken—important program components. Centrally dictated strategies developed at WHO offices in Geneva and New Delhi, often in association with Indian federal authorities, were reinterpreted by many actors and sometimes changed beyond recognition

    Original Antigenic Sin and Pandemic (H1N1) 2009

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    Multifaceted contributions : health workers and smallpox eradication in India

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    Smallpox eradication in South Asia was a result of the efforts of many grades of health-workers. Working from within the confines of international organisations and government structures, the role of the field officials, who were of various nationalities and also drawn from the cities and rural enclaves of the countries in these regions, was crucial to the development and deployment of policies. However, the role of these personnel is often downplayed in official histories and academic histories, which highlight instead the roles played by a handful of senior officials within the World Health Organization and the federal governments in the sub-continent. This article attempts to provide a more rounded assessment of the complex situation in the field. In this regard, an effort is made to underline the great usefulness of the operational flexibility displayed by field officers, wherein lessons learnt in the field were made an integral part of deploying local campaigns; careful engagement with the communities being targeted, as well as the employment of short term workers from amongst them, was an important feature of this work

    Knowledge practices in design: The role of visual representations as 'epistemic objects'

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    We use a detailed study of the knowledge work around visual representations to draw attention to the multidimensional nature of `objects'. Objects are variously described in the literatures as relatively stable or in flux; as abstract or concrete; and as used within or across practices. We clarify these dimensions, drawing on and extending the literature on boundary objects, and connecting it with work on epistemic and technical objects. In particular, we highlight the epistemic role of objects, using our observations of knowledge work on an architectural design project to show how, in this setting, visual representations are characterized by a `lack' or incompleteness that precipitates unfolding. The conceptual design of a building involves a wide range of technical, social and aesthetic forms of knowledge that need to be developed and aligned. We explore how visual representations are used, and how these are meaningful to different stakeholders, eliciting their distinct contributions. As the project evolves and the drawings change, new issues and needs for knowledge work arise. These objects have an `unfolding ontology' and are constantly in flux, rather than fully formed. We discuss the implications for wider understandings of objects in organizations and for how knowledge work is achieved in practice

    An assessment of the resolution limitation due to radiation-damage in x-ray diffraction microscopy

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    X-ray diffraction microscopy (XDM) is a new form of x-ray imaging that is being practiced at several third-generation synchrotron-radiation x-ray facilities. Although only five years have elapsed since the technique was first introduced, it has made rapid progress in demonstrating high-resolution threedimensional imaging and promises few-nm resolution with much larger samples than can be imaged in the transmission electron microscope. Both life- and materials-science applications of XDM are intended, and it is expected that the principal limitation to resolution will be radiation damage for life science and the coherent power of available x-ray sources for material science. In this paper we address the question of the role of radiation damage. We use a statistical analysis based on the so-called "dose fractionation theorem" of Hegerl and Hoppe to calculate the dose needed to make an image of a lifescience sample by XDM with a given resolution. We conclude that the needed dose scales with the inverse fourth power of the resolution and present experimental evidence to support this finding. To determine the maximum tolerable dose we have assembled a number of data taken from the literature plus some measurements of our own which cover ranges of resolution that are not well covered by reports in the literature. The tentative conclusion of this study is that XDM should be able to image frozen-hydrated protein samples at a resolution of about 10 nm with "Rose-criterion" image quality.Comment: 9 pages, 4 figure

    Reaching across continents : engaging students through virtual collaborations

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    Business schools have the responsibility of preparing students for work in multicultural organizations and global markets. This paper examines a situated learning experience for undergraduates through a virtual collaboration between a UK university and a Brazilian university. This facilitated remote communication using social media and smart devices, allowing students from both institutions to enhance their cross-cultural management competencies. A qualitative approach was used for the research, drawing on the reflections of the tutors from both institutions, and feedback received from students in the UK and Brazil. This paper provides empirical observations regarding the use of this innovative pedagogic approach, generating discussion of the implications for teaching, thus contributing to the literature on international collaborations in cross-cultural management education

    Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study

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    This study explores the potential to enhance the reflectance of solar insolation by the human settlement and grassland components of the Earth's terrestrial surface as a climate change mitigation measure. Preliminary estimates derived using a static radiative transfer model indicate that such efforts could amplify the planetary albedo enough to offset the current global annual average level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30 percent or 0.76 W/m2. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. However, additional study is needed to confirm the estimates reported here and to assess the economic and environmental impacts of active land-surface albedo amplification as a climate change mitigation measure.Comment: 21 pages, 3 figures. In press with Mitigation and Adaptation Strategies for Global Change, Springer, N

    Maximum likelihood kernel density estimation: On the potential of convolution sieves

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    Methods for improving the basic kernel density estimator include variable locations, variable bandwidths and variable weights. Typically these methods are implemented separately and via pilot estimation of variation functions derived from asymptotic considerations. The starting point here is a simple maximum likelihood procedure which allows (in its greatest generality) variation of all these quantities at once, bypassing asymptotics and explicit pilot estimation. One special case of this approach is the density estimator associated with nonparametric maximum likelihood estimation (NPMLE) in a normal location mixture model. Another, closely associated with the NPMLE, is a kernel convolution sieve estimator proposed in 1982 but little used in practice to date. Simple algorithms are utilised, a simulation study is reported on, a method for bandwidth selection is investigated and an illustrative example is given. The simulations and other considerations suggest that the kernel convolution sieve provides an especially promising framework for further practical utilisation and development. And the method has a further advantage: it automatically reduces, where appropriate, to a few-component mixture model which indicates and initialises parametric mixture modelling of the data

    Peak effect and its evolution with defect structure in YBa2Cu3O7-d thin films at microwave frequencies

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    The vortex dynamics in YBa2Cu3O7-d thin films have been studied at microwave frequencies. A pronounced peak in the surface resistance, Rs, is observed in these films at frequencies of 4.88 and 9.55 GHz for magnetic fields varying from 0.2 to 0.8 T. The peak is associated with an order-disorder transformation of the flux line lattice as the temperature or field is increased. The occurrence of the peak in Rs is crucially dependent on the depinning frequency, wp and on the nature and concentration of growth defects present in these films. Introduction of artificial defects by swift heavy ion irradiation with 200 MeV Ag ion at a fluence of 4x1010 ions/cm2 enhances wp and suppresses the peak at 4.88 GHz but the peak at 9.55 GHz remains unaffected. A second peak at lower temperature has also been observed at 9.55 GHz. This is related to twin boundaries from angular dependence studies of Rs. Based on the temperature variation of Rs, vortex phase diagrams have been constructed at 9.55 GHz.Comment: 8 pages, 4 figures Submitted to Physical Review

    Resistance in Enterobacterales Is Higher among People Living with Human Immunodeficiency Virus

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    Background: Multidrug-resistant Enterobacterales (MDR-E) are important pathogens. People living with human immunodeficiency virus (HIV; PLWH) may be at greater risk for MDR-E infection given relatively high antibiotic exposure and burden of comorbidities. Methods: We analyzed data from 36 521 patients in a healthcare system in North Carolina who had a clinical culture with growth of an Enterobacterales species from 2000 to 2018; 440 were PLWH. We used generalized linear models to estimate prevalence ratios and differences, contrasting PLWH and people not living with HIV (PNLWH) for resistance to individual antibiotic classes, as well as MDR-E. We assessed trends in prevalence over time by calculating the 5-year moving average and fitting restricted cubic spline models. Results: The overall prevalence of MDR-E was higher among PLWH (21.5%; 95% confidence interval [CI], 18.2%-25.1%) vs PNLWH (16.5%; 95% CI, 16.2%-16.9%), with an adjusted prevalence ratio of 1.38 (95% CI, 1.14-1.65). PLWH had higher rates of antimicrobial resistance than PNLWH for all antibiotic classes analyzed, including penicillins, penicillin/beta lactamase inhibitor combinations, and sulfonamides. MDR-E prevalence was 3 to 10 percentage points higher among PLWH than PNLWH throughout the study period based on the 5-year moving average. Conclusions: In a large clinical study population in the southeastern United States from 2000 to 2018, the prevalence of antibacterial resistance among Enterobacterales was consistently higher among PLWH than PNLWH. These data highlight the importance of identifying and mitigating the factors that contribute to antimicrobial resistance in PLWH, given the potential clinical consequences of these resistant pathogens
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