Characterizing Multiple Spatial Waves of the 1991-1997 Cholera Epidemic in Peru

Background Due to a lack of sanitary infrastructure and a highly susceptible population, Peru experienced a historic outbreak of Vibrio cholerae O1 that began in 1991 and generated multiple waves of disease for several years. Though case-fatality was low, the epidemic put massive strain on healthcare and governmental resources. Here we explore the transmission dynamics and spatiotemporal variation of cholera in Peru using mathematical models and statistical analyses that account for environmental conditions favoring the persistence of bacteria in the environment. Methods The authors use dynamic transmission models that incorporate seasonal variation in temperature, concentration of vibrios in the environment, as well as separate human and environmental transmission pathways. The model is fit to weekly department level data obtained from the cholera surveillance system in Peru. The authors also assess the spatial patterns of cholera transmission and correlations between case incidence, time of epidemic onset, and department level variables. Reproductive numbers are compared across departments. Results Our findings indicate that the epidemic first hit the coastal departments of Peru and later spread through the highlands and jungle regions. There was high seasonal variation in case incidence, with three clear waves of transmission corresponding to the warm seasons in Peru. Department level variables such as population size and elevation also played a role in transmission patterns. Finally, basic reproductive numbers most often ranged from one to eleven depending on department and time of year. Lima had the largest reproductive number, likely due to its population density and proximity to the coast. Conclusions Incorporating environmental variables into an epidemic model predicts the multiple waves of transmission characteristic of \textit{V. cholerae}, and effectively differentiates transmission patterns by geographic region even in the absence of unique parameter estimates. Mathematical models can provide valuable information about transmission patterns and should continue to be used to inform public health decision making

Theory of Dimensions

This chapter concerns dimensions as the term is used in the physical sciences today. Some key points made are: (i) Quantities of the same kind have the same dimension; but that two quantities have the same dimension does not necessarily mean they are of the same kind. (ii) The dimension of a quantity is not determined for a single quantity in isolation, but relative to a system of quantities and the relations that hold between them. (iii) Dimensions, units, and quantities are distinct notions. In this article, I explain how dimensions, units, and quantities are involved in the design of coherent systems of units; the account involves the equations of physics. When the use of a coherent system of units can be presumed, dimensional analysis is a powerful logico-mathematical method for deriving equations and relations in physics, and for parameterizing equations in terms of dimensionless parameters, which allows identifying physically similar systems. The source of the information yielded by dimensional analysis is not yet well understood in philosophy of physics. This chapter aims to reveal the role of dimensions not only in applications of dimensional analysis to obtain information by involving the principle of dimensional homogeneity, but to the role of dimensions in encoding information about physical relationships in the language of dimensions, specifically via the feature of coherence of a system of units. Philosophers of mathematics and philosophers of science have been concerned to address the question of the effectiveness of mathematics in science. It is argued here that no philosophical analysis of the question of the applicability of mathematics to science is complete without including dimensions and dimensional analysis in the picture

Theory of Dimensions

This chapter concerns dimensions as the term is used in the physical sciences today. Some key points made are: (i) Quantities of the same kind have the same dimension; but that two quantities have the same dimension does not necessarily mean they are of the same kind. (ii) The dimension of a quantity is not determined for a single quantity in isolation, but relative to a system of quantities and the relations that hold between them. (iii) Dimensions, units, and quantities are distinct notions. In this article, I explain how dimensions, units, and quantities are involved in the design of coherent systems of units; the account involves the equations of physics. When the use of a coherent system of units can be presumed, dimensional analysis is a powerful logico-mathematical method for deriving equations and relations in physics, and for parameterizing equations in terms of dimensionless parameters, which allows identifying physically similar systems. The source of the information yielded by dimensional analysis is not yet well understood in philosophy of physics. This chapter aims to reveal the role of dimensions not only in applications of dimensional analysis to obtain information by involving the principle of dimensional homogeneity, but to the role of dimensions in encoding information about physical relationships in the language of dimensions, specifically via the feature of coherence of a system of units. Philosophers of mathematics and philosophers of science have been concerned to address the question of the effectiveness of mathematics in science. It is argued here that no philosophical analysis of the question of the applicability of mathematics to science is complete without including dimensions and dimensional analysis in the picture

INTERPERSONAL COMPETENCY CONFIGURATIONS AND THE SCHOOL ADJUSTMENT OF EARLY ADOLESCENTS WITH DISABILITIES: A PERSON-CENTERED APPROACH

The transition to middle school is a critical time in adolescence. The more complex school environment provides opportunities for growth and challenges for students with disabilities. Although special education strives to provide individualized supports to students with disabilities through data-based decision-making, the tools used to understand and meet the needs of these students are often unresponsive to the dynamic nature of development and student adjustment as they age. Grounded in developmental science, this study sought to create a data collection framework through a person-centered approach to inform the individualization process. Specifically, this study: 1) explored a decision process that allows interventionists to place students in well-established interpersonal competency configurations that can guide interventions; 2) understand how different academic, behavioral, and emotional outcomes are related to SWD in specific configurations, and if these outcomes change from 6th to 7th grade, and 3) clarify potential process variables and their interactions with students within specific configurations to explore how these variables contribute to student functioning and potential adaptations. Results established a process practitioners can use to place SWD in configurations informed by interpersonal competencies and provided insight into differential patterns of adjustment and developmental mechanisms that are associated with different trajectories and outcomes for SWD in middle school

Relations Between Units and Relations Between Quantities

The proposed revision to the International System of Units contains two features that are bound to be of special interest to those concerned with foundational questions in philosophy of science. These are that the proposed system of international units ("New SI") can be defined (i) without drawing a distinction between base units and derived units, and (ii) without restricting (or, even, specifying) the means by which the value of the quantities associated with the units are to be established. In this paper, I address the question of the role of base units in light of the New SI: Do the "base units" of the SI play any essential role anymore, if they are neither at the bottom of a hierarchy of definitions themselves, nor the only units that figure in the statements fixing the numerical values of the "defining constants" ? The answer I develop and present (a qualified yes and no) also shows why it is important to retain the distinction between dimensions and quantities. I argue for an appreciation of the role of dimensions in understanding issues related to systems of units

"Pictures, Models, and Measures" A contribution to Invited Symposium: "Wittgenstein's Picture Theory" at the 2015 Pacific APA Meeting

Putting Wittgenstein's writing into an historical context that includes scientific and technological developments as well as cultural and intellectual works can be helpful in understanding some of Wittgenstein's works. I focus on the Tractatus Logico-Philosophicus in particular in this paper, and on topics related to pictures and models: the development of audio recording technologies, the development of miniature scale models that were both aesthetically pleasing and scientifically useful, particularly in the forensics of traffic accidents, and the culmination of a centuries-long effort to articulate the method behind the use of physical modeling, i.e., the formulation of a concept presented in 1914 and dubbed "physically similar systems.

The social significance of Richard Allen in the organization and work of the African Methodist Episcopal Church

Thesis (M.A.)--Boston Universit

Relations Between Units and Relations Between Quantities

The proposed revision to the International System of Units contains two features that are bound to be of special interest to those concerned with foundational questions in philosophy of science. These are that the proposed system of international units ("New SI") can be defined (i) without drawing a distinction between base units and derived units, and (ii) without restricting (or, even, specifying) the means by which the value of the quantities associated with the units are to be established. In this paper, I address the question of the role of base units in light of the New SI: Do the "base units" of the SI play any essential role anymore, if they are neither at the bottom of a hierarchy of definitions themselves, nor the only units that figure in the statements fixing the numerical values of the "defining constants" ? The answer I develop and present (a qualified yes and no) also shows why it is important to retain the distinction between dimensions and quantities. I argue for an appreciation of the role of dimensions in understanding issues related to systems of units