1,149 research outputs found

    Products of Compartmental Models in Epidemiology.

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    We show that many structured epidemic models may be described using a straightforward product structure in this paper. Such products, derived from products of directed graphs, may represent useful refinements including geographic and demographic structure, age structure, gender, risk groups, or immunity status. Extension to multistrain dynamics, that is, pathogen heterogeneity, is also shown to be feasible in this framework. Systematic use of such products may aid in model development and exploration, can yield insight, and could form the basis of a systematic approach to numerical structural sensitivity analysis

    The Solubility of Metallic Salts of Some Organic Acids in a Methyl Alcohol-Acetone Mixture

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    The writer of this thesis is interested in the investigation of this subject because of the numerous metallic salts of the organic acids known to the chemist. These salts under investigation, including many others, are of great importance in the process of life. Moreover, salts of organic acids are important, in that, they are used in the preparation of various organic compounds and finally, a group of them belongs to those household substances which go under the common name of soap. In both the plant and the animal kingdom salts of organic, as well as inorganic, acids are necessary. In view of this fact it is vitally important to know just how soluble these salts are; in what solvents are they most soluble, and what properties they possess that influence their solubilities

    Hamiltonian analysis of subcritical stochastic epidemic dynamics

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    We extend a technique of approximation of the long-term behavior of a supercritical stochastic epidemic model, using the WKB approximation and a Hamiltonian phase space, to the subcritical case. The limiting behavior of the model and approximation are qualitatively different in the subcritical case, requiring a novel analysis of the limiting behavior of the Hamiltonian system away from its deterministic subsystem. This yields a novel, general technique of approximation of the quasistationary distribution of stochastic epidemic and birth-death models, and may lead to techniques for analysis of these models beyond the quasistationary distribution. For a classic SIS model, the approximation found for the quasistationary distribution is very similar to published approximations but not identical. For a birth-death process without depletion of susceptibles, the approximation is exact. Dynamics on the phase plane similar to those predicted by the Hamiltonian analysis are demonstrated in cross-sectional data from trachoma treatment trials in Ethiopia, in which declining prevalences are consistent with subcritical epidemic dynamics

    Clement of Alexandria : Incarnation and mission of the Logos-Son

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    Clementine scholarship acknowledges Clement’s doctrine of the Incarnation and generally maintains that for Clement the divine Logos assumed human flesh. However, because of Clement’s complex logology and three passages suggesting a docetic interpretation of Christ’s flesh, scholars tend to move away from addressing the Incarnation and treat either the metaphysics of the multiple logoi theory or the question of Clement’s Docetism, or both. Because of this diversion in research, there remains a gap in the literature around Clement’s teachings about the Incarnation. This thesis begins to fill the gap by explaining Clement’s view of the Incarnation, which he connects to the emergent ‘exchange’ doctrine, envisaged as a divine mission. It situates Clement as an heir of the apostolic tradition while he engages with Greek philosophy and Gnostic belief. The research delineates Clement’s gnostic tradition, which he considered faithful to the Old Testament and to the teachings of the apostles. The investigation collates Clement’s usage of John 1:14 and the term ginomai linked with Logos, anthropos, and sarx. It examines Clement’s discussion in Stromateis VII.2, where he claims the Logos assumed flesh susceptible to suffering, emotions, and physical sensibilities. In Clement’s teachings, the Logos became both anthropos and sarx so that anthropos might become theos. This thesis outlines Clement’s usage of the terms parousia and epiphaneia (appearing), showing they are consequential to the Incarnation. Clement presents the Logos as Saviour, who conquers malevolent powers and death to release humankind from corruption through his sufferings from birth to the cross. Clement also presents the Logos as a Teacher, who during his parousia, interprets precisely the Old Testament, and in his appearing, discloses true gnosis, which guides anthropos to godliness. The evidence demonstrates that Clement bases his path for assimilation to God upon the Incarnation of the Logos

    Short-term leprosy forecasting from an expert opinion survey.

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    We conducted an expert survey of leprosy (Hansen's Disease) and neglected tropical disease experts in February 2016. Experts were asked to forecast the next year of reported cases for the world, for the top three countries, and for selected states and territories of India. A total of 103 respondents answered at least one forecasting question. We elicited lower and upper confidence bounds. Comparing these results to regression and exponential smoothing, we found no evidence that any forecasting method outperformed the others. We found evidence that experts who believed it was more likely to achieve global interruption of transmission goals and disability reduction goals had higher error scores for India and Indonesia, but lower for Brazil. Even for a disease whose epidemiology changes on a slow time scale, forecasting exercises such as we conducted are simple and practical. We believe they can be used on a routine basis in public health

    Spatial heterogeneity in projected leprosy trends in India

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    Background: Leprosy is caused by infection with Mycobacterium leprae and is characterized by peripheral nerve damage and skin lesions. The disease is classified into paucibacillary (PB) and multibacillary (MB) leprosy. The 2012 London Declaration formulated the following targets for leprosy control: (1) global interruption of transmission or elimination by 2020, and (2) reduction of grade-2 disabilities in newly detected cases to below 1 per million population at a global level by 2020. Leprosy is treatable, but diagnosis, access to treatment and treatment adherence (all necessary to curtail transmission) represent major challenges. Globally, new case detection rates for leprosy have remained fairly stable in the past decade, with India responsible for more than half of cases reported annually. Methods: We analyzed publicly available data from the Indian Ministry of Health and Family Welfare, and fit linear mixed-effects regression models to leprosy case detection trends reported at the district level. We assessed correlation of the new district-level case detection rate for leprosy with several state-level regressors: TB incidence, BCG coverage, fraction of cases exhibiting grade 2 disability at diagnosis, fraction of cases in children, and fraction multibacillary. Results: Our analyses suggest an endemic disease in very slow decline, with substantial spatial heterogeneity at both district and state levels. Enhanced active case finding was associated with a higher case detection rate. Conclusions: Trend analysis of reported new detection rates from India does not support a thesis of rapid progress in leprosy control

    Collaborative Power: Graduate Students Creating and Implementing Faculty Development Workshops on Multilingual Writing Pedagogy

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    The increasing numbers multilingual students in US universities, whether international students or multilingual citizens and permanent residents, have made it clear that students’ language needs can no longer be relegated to the ‘experts’ in specialized courses or tutoring centers. All faculty will teach multilingual students, yet few faculty have received specialized training to prepare them to work effectively with the multilingual writers in their classrooms. While there is a need for professional development efforts designed to help faculty more effectively teach multilingual writing, institutional divisions between first language (L1) and second language (L2) writing instruction pose challenges for the organization and delivery of such professional development efforts. One way to overcome such challenges is through grassroots forms of collaboration across institutional boundaries. This article reports on one such grassroots effort, the creation of two faculty development workshops designed to help teachers across the disciplines to work more effectively with multilingual writers. These workshops were unique in that they were initiated by an interdisciplinary graduate student led research group. This article describes the formation of this group, the creation and curriculum of the workshops, and ongoing adaptation of the workshops for new audiences. We also consider faculty responses to the workshops and reflect on the challenges and rewards of such grassroots collaborative efforts
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