289 research outputs found

    Understanding disease control: influence of epidemiological and economic factors

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    We present a local spread model of disease transmission on a regular network and compare different control options ranging from treating the whole population to local control in a well-defined neighborhood of an infectious individual. Comparison is based on a total cost of epidemic, including cost of palliative treatment of ill individuals and preventive cost aimed at vaccination or culling of susceptible individuals. Disease is characterized by pre- symptomatic phase which makes detection and control difficult. Three general strategies emerge, global preventive treatment, local treatment within a neighborhood of certain size and only palliative treatment with no prevention. The choice between the strategies depends on relative costs of palliative and preventive treatment. The details of the local strategy and in particular the size of the optimal treatment neighborhood weakly depends on disease infectivity but strongly depends on other epidemiological factors. The required extend of prevention is proportional to the size of the infection neighborhood, but this relationship depends on time till detection and time till treatment in a non-nonlinear (power) law. In addition, we show that the optimal size of control neighborhood is highly sensitive to the relative cost, particularly for inefficient detection and control application. These results have important consequences for design of prevention strategies aiming at emerging diseases for which parameters are not known in advance

    Primordialists and Constructionists: a typology of theories of religion

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    This article adopts categories from nationalism theory to classify theories of religion. Primordialist explanations are grounded in evolutionary psychology and emphasize the innate human demand for religion. Primordialists predict that religion does not decline in the modern era but will endure in perpetuity. Constructionist theories argue that religious demand is a human construct. Modernity initially energizes religion, but subsequently undermines it. Unpacking these ideal types is necessary in order to describe actual theorists of religion. Three distinctions within primordialism and constructionism are relevant. Namely those distinguishing: a) materialist from symbolist forms of constructionism; b) theories of origins from those pertaining to the reproduction of religion; and c) within reproduction, between theories of religious persistence and secularization. This typology helps to make sense of theories of religion by classifying them on the basis of their causal mechanisms, chronology and effects. In so doing, it opens up new sightlines for theory and research

    Avaliação sistêmica do setor industrial brasileiro: 1995-2009

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    Resumo O presente artigo busca avaliar o setor industrial sob uma ótica distinta da que tem sido utilizada quando se trata de industrialização/desindustrialização. O objetivo é analisar o caráter sistêmico do setor industrial a partir do método de insumo-produto, por meio de indicadores de intensidade direta e intensidade direta mais indireta da indústria. Por esta medida, é possível deixar mais clara a contribuição do artigo, ou seja, fornecer uma medida de integração produtiva do setor industrial com os demais setores, de modo a verificar se a indústria tem ganhado importância relativa como setor articulador das atividades produtivas

    The deindustrialisation/tertiarisation hypothesis reconsidered: a subsystem application to the OECD7

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    The diffusion of outsourcing, both national and international, and vertical FDIs among manufacturing firms, along with the higher integra- tion of business services in manufacturing, has recently led to question the empirical evidence supporting the Deindustrialisation/Tertiarisation (DT) hypothesis. Rather than a \real" phenomenon, it has been argued, DT would be an \apparent" one, mainly due to the reorganization of production across national and sectoral boundaries. The empirical studies that have dealt with the topic so far have not been able to effectively rule out such possibility, because of two main limitations: the sectoral level of the analysis and/or the national focus. In order to overcome them, the paper carries out an appreciative investigation of the actual extent of the DT occurred in the OECD area over the '80s and the '90s by moving from a sector to a subsystem perspective, thus retaining both direct and indirect relations, and by referring to a \pseudo-World" of 7 OECD countries, thus taking into account the \global" dimension of the phenomenon. The results strongly support the DT hypothesis: although the weight of business sector services in the manufacturing subsystem increased, acting as a counterbalancing tendency to the manufacturing decline, subsystem shares significantly decreased, thus confirming DT as a more fundamental trend of modern economies

    Balancing Detection and Eradication for Control of Epidemics: Sudden Oak Death in Mixed-Species Stands

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    Culling of infected individuals is a widely used measure for the control of several plant and animal pathogens but culling first requires detection of often cryptically-infected hosts. In this paper, we address the problem of how to allocate resources between detection and culling when the budget for disease management is limited. The results are generic but we motivate the problem for the control of a botanical epidemic in a natural ecosystem: sudden oak death in mixed evergreen forests in coastal California, in which species composition is generally dominated by a spreader species (bay laurel) and a second host species (coast live oak) that is an epidemiological dead-end in that it does not transmit infection but which is frequently a target for preservation. Using a combination of an epidemiological model for two host species with a common pathogen together with optimal control theory we address the problem of how to balance the allocation of resources for detection and epidemic control in order to preserve both host species in the ecosystem. Contrary to simple expectations our results show that an intermediate level of detection is optimal. Low levels of detection, characteristic of low effort expended on searching and detection of diseased trees, and high detection levels, exemplified by the deployment of large amounts of resources to identify diseased trees, fail to bring the epidemic under control. Importantly, we show that a slight change in the balance between the resources allocated to detection and those allocated to control may lead to drastic inefficiencies in control strategies. The results hold when quarantine is introduced to reduce the ingress of infected material into the region of interest

    Democracy in trade unions, democracy through trade unions?

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    Since the Webbs published Industrial Democracy at the end of the nineteenth century, the principle that workers have a legitimate voice in decision-making in the world of work – in some versions through trade unions, in others at least formally through separate representative structures – has become widely accepted in most west European countries. There is now a vast literature on the strengths and weaknesses of such mechanisms, and we review briefly some of the key interpretations of the rise (and fall) of policies and structures for workplace and board-level representation. We also discuss the mainly failed attempts to establish broader processes of economic democracy, which the eclipse of nationally specific mechanisms of class compromise makes again a salient demand. Economic globalization also highlights the need for transnational mechanisms to achieve worker voice (or more radically, control) in the dynamics of capital-labour relations. We therefore examine the role of trade unions in coordinating pressure for a countervailing force at European and global levels, and in the construction of (emergent?) supranational industrial relations. However, many would argue that unions cannot win legitimacy as democratizing force unless manifestly democratic internally. We therefore revisit debates on and dilemmas of democracy within trade unions, and examine recent initiatives to enhance democratization

    Epidemic centrality - is there an underestimated epidemic impact of network peripheral nodes?

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    In the study of disease spreading on empirical complex networks in SIR model, initially infected nodes can be ranked according to some measure of their epidemic impact. The highest ranked nodes, also referred to as "superspreaders", are associated to dominant epidemic risks and therefore deserve special attention. In simulations on studied empirical complex networks, it is shown that the ranking depends on the dynamical regime of the disease spreading. A possible mechanism leading to this dependence is illustrated in an analytically tractable example. In systems where the allocation of resources to counter disease spreading to individual nodes is based on their ranking, the dynamical regime of disease spreading is frequently not known before the outbreak of the disease. Therefore, we introduce a quantity called epidemic centrality as an average over all relevant regimes of disease spreading as a basis of the ranking. A recently introduced concept of phase diagram of epidemic spreading is used as a framework in which several types of averaging are studied. The epidemic centrality is compared to structural properties of nodes such as node degree, k-cores and betweenness. There is a growing trend of epidemic centrality with degree and k-cores values, but the variation of epidemic centrality is much smaller than the variation of degree or k-cores value. It is found that the epidemic centrality of the structurally peripheral nodes is of the same order of magnitude as the epidemic centrality of the structurally central nodes. The implications of these findings for the distributions of resources to counter disease spreading are discussed
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