Analysis of CDC social control measures using an agent-based simulation of an influenza epidemic in a city

Background: the transmission of infectious disease amongst the human population is a complex process which requires advanced, often individual-based, models to capture the space-time details observed in reality.Methods: an Individual Space-Time Activity-based Model (ISTAM) was applied to simulate the effectiveness of non-pharmaceutical control measures including: (1) refraining from social activities, (2) school closure and (3) household quarantine, for a hypothetical influenza outbreak in an urban area.Results: amongst the set of control measures tested, refraining from social activities with various compliance levels was relatively ineffective. Household quarantine was very effective, especially for the peak number of cases and total number of cases, with large differences between compliance levels. Household quarantine resulted in a decrease in the peak number of cases from more than 300 to around 158 for a 100% compliance level, a decrease of about 48.7%. The delay in the outbreak peak was about 3 to 17 days. The total number of cases decreased to a range of 3635-5403, that is, 63.7%-94.7% of the baseline value.When coupling control measures, household quarantine together with school closure was the most effective strategy. The resulting space-time distribution of infection in different classes of activity bundles (AB) suggests that the epidemic outbreak is strengthened amongst children and then spread to adults. By sensitivity analysis, this study demonstrated that earlier implementation of control measures leads to greater efficacy. Also, for infectious diseases with larger basic reproduction number, the effectiveness of non-pharmaceutical measures was shown to be limited.Conclusions: simulated results showed that household quarantine was the most effective control measure, while school closure and household quarantine implemented together achieved the greatest benefit. Agent-based models should be applied in the future to evaluate the efficacy of control measures for a range of disease outbreaks in a range of settings given sufficient information about the given case and knowledge about the transmission processes at a fine scal

PUMA - a multi-agent model of urban systems

It is increasingly recognised that land use change processes are the outcome of decisions made by individual actors, such as land owners, authorities, firms and households. As multi-agent models provide a natural framework for modelling urban processes on the level of individual actors, Utrecht University, Eindhoven University of Technology and RIVM are developing PUMA (Predicting Urbanisation with Multi-Agents), a full fledged multi-agent system of urban processes. PUMA consists of various modules, representing the behaviours of specific actors. The land conversion module describes farmers', authorities', investors' and developers' decisions to sell or buy land and develop it into other uses. The households module describes households' housing careers in relation to life cycle events (marriage, child birth, aging, job change etc.). The firms module includes firms' demography and their related demand for production facilities leading to location choice processes. The daily activity pattern module describes the trips made and locations visited by individuals to carry out certain tasks. This module generates aggregated effects of individual behaviours (congestion, pollution, noise), affecting households' or firms' longer term location decisions. The paper describes the model system architecture and the interactions between the modules. Particular attention is devoted to the households module that includes a behaviourally sophisticated model of households' process of awakening (deciding to actively search for another dwelling), search and acceptance of an offered dwelling. This model was calibrated on the Dutch Housing Preferences Survey. Based on the disaggregate housing search and acceptance model, the households module describes housing market dynamics and indicates the demand for new dwellings per region. The paper describes the model specification and calibration in detail. The households module was implemented and tested for the Northwing of the Dutch Randstad, including about 1.5 million households and 1.6 million dwellings. The paper describes the implementation and the first model results.

Road pricing and (re)location decisions households

Road pricing policies are, after a cooling down period of a couple of years, again prominently back on the political agenda in the Netherlands. But also in the period of less political interest, research in the field of (road) pricing policies continued in other countries as well as in the Netherlands. Most research literature focuses on the economic and acceptability aspects of pricing policies. The geographical aspects of transport pricing however have received much less attention so far. This paper focuses on possible influences of road pricing policies on residential and work location choice of households. The paper starts with analyzing the importance of transport and location related variables in residential location decisions, when the choice to relocate itself has been made. For this analysis data from a stated choice experiment is used. Choice screens within the experiment consisted of two alternatives. In total, per respondent nine choice screens were shown. Transport related variables within the experiment were commuting travel time, fuel cost and toll cost. The location related variables consisted of the residential environment, the number of bedrooms and the monthly housing costs. Analysis of the results gives insight into the importance of for example toll costs on the final location choice when a decision to relocate itself has already been made. However this type of analysis does not give insight into the number of people who are actually considering changing location when a form of road pricing is introduced. Therefore the second part of the paper continues with analyzing the extent to which people are likely to relocate due to road pricing. The effect of different types of pricing measures and pricing levels on this inclination to relocate are examined. For the analysis, data from a stated preference questionnaire is used. The paper finally concludes with an examination of important explaining variables for moving house or changing job due to road pricing. Some important findings are for example that older people (above 40 years of age), people with a higher income and persons getting a travel cost compensation from their employer are less willing to move due to a pricing measure. People with a higher education level however are more willing to relocate.

Taste Heterogeneity and Substitution Patterns in Models of the Simultaneous Choice of Activity Timing and Duration

The recent growth of interest in activity-based methods has focused particular attention on travellers’ decision making regarding the timing and duration of their participation in activities. However, to date these two dimensions of activity participation have been largely treated separately. It is clear, however, that in general, the benefit that an individual derives from participating in an activity will depend inter alia both upon the time at which the activity is undertaken and the amount of time devoted to the activity. Moreover, it is also clear that this benefit will also depend on a wide range of other factors such as the quality of the activity opportunities available at particular destinations and the intensity with which activities are undertaken. Since these factors are inherently difficult or impossible to completely characterise or measure via conventional travel or time use data sources, it is likely that such decisions will also be characterised by significant unobserved heterogeneity. Based on earlier theoretical work by the authors, this paper proposes a model for the simultaneous choice of the timing and duration of activities and associated travel and uses data from a stated preference experiment to estimate the parameters of this model. The first section of the paper provides a brief review of the existing literature on activity timing and duration choice. The second section introduces the theoretical approach, which assume that the marginal utility derived from activities encompasses two distinct components; one derived from the duration of activity involvement and the other derived from activity participation at a particular time-of-day. A number of alternative additive and multiplicative specifications are introduced and their properties are explored. The third section briefly describes the stated preference data, which was collected in a survey undertaken in London in which respondents were presented with a number of scenarios in which they were asked to choose between alternative tours involving a single destination activity. The timing and duration both of the destination activity and the associated travel varied across scenarios. The fourth section discusses the empirical specification and estimation of the model and presents the estimation results. This uses an error-components formulation of the mixed multinomial logit model to account both for unobserved heterogeneity in tastes and for heteroskedascity and complex substitution patterns amongst activity alternatives. Particular attention is given to the use of advanced optimisation techniques needed to estimate the non-linear utility function expressing individuals’ timing and duration preferences.The fifth section discusses the significance of the results and their potential application to a number of practical transport planning problems including the prediction of user response to travel demand management policies and accessibility planning. The paper closes with some overall conclusions and a discussion of future research directions.

Elastic and length-force characteristics of the gastrocnemius of the hopping mouse (Notomys alexis) and the rat (Rattus norvegicus)

The aim of this study was to compare the contractile and series elastic properties of terrestrial mammals that use bipedal versus quadrupedal gaits. The gastrocnemius muscle of the hopping mouse (body mass 30.2 +/- 2.4 g, mean +/- S.D.) and the rat (313 +/- 10.7 g) were compared with data from the literature for the wallaby and the kangaroo rat to distinguish scaling effects and locomotion-related effects on muscle properties. Contractile length-force properties and series elastic stiffness were measured in situ during maximal tetanic contractions. The rat had a larger muscle-fibre-to-tendon-length ratio. The rat and hopping mouse showed similar normalised length-force characteristics of the gastrocnemius. Normalised stiffness in the hopping mouse was higher. The hopping mouse showed a higher capacity to store elastic energy per unit of contractile work capacity, as well as per unit of body mass. Accounting for body size differences, the rat had a smaller relative muscle mass and thus smaller work capacity than the three hopping animals considered. This is an agreement with a quadrupedal versus bipedal locomotion style. The differences in contractile and elastic properties of the gastrocnemius of the rat and hopping mouse seem to be closely related to locomotion patterns. Small animals seem to be able to utilise the storage and release of elastic energy to a far lesser extent than larger animals. However, even in animals as small as hopping mice, the storage and utilisation of elastic energy during locomotion is of functional significance and probably depends on locomotor behaviour

Концепт міста й бінарна опозиція “місто / село” у хронотопі Слісаренкової прози

Стаття присвячена виявленню своєрідності зображення міста у прозі О. Слісаренка. Для більшості прозових творів О. Слісаренка характерна наявність антитези “місто / село”, яка розглядається автором у різних ракурсах. Місто виступає у творчості письменника втіленням хаосу, на відміну від сільського простору, який символізує спокій і сталість. У роботі досліджується відображення у прозі О. Слісаренка процесів урбанізації та пов’язаних з ними проблем, а також їх вплив на життя окремої людини і суспільства. Ключові слова: проза, часопростір, футуризм, місто, урбанізація, опозиція “місто / село”, символ.Статья посвящена определению специфики изображения города в прозе О. Слисаренко. Для большинства прозаических произведений О. Слисаренко характерно наличие оппозиции город / село, рассматриваемой автором в различных ракурсах. Город выступает в творчестве писателя воплощением хаоса, в отличие от сельского пространства, символизирующего покой и постоянство. В работе исследуется отражение в прозе О. Слисаренко процессов урбанизации и связанных с ними проблем, а также их влияние на жизнь человека и общества. Ключевые слова: проза, хронотоп, футуризм, город, урбанизация, оппозиция “город / село”, символ.The article is devoted to the determination of special features of imaging the city in the prose by O. Slisarenko. Most prosaic works by O. Slisarenko present the opposition the city / country, examined by the author from different sides. On the contrast to the country which symbolizes rest and constancy, a city is shown by the author as a chaotic space. The reflection of the urbanizational processes and related to them problems and their influence on human and social life in O. Slisarenko’s prose are studied in the work. Keywords: prose, chronotope, futurism, city, urbanization, opposition “city / country”, symbol

PUMA - a multi-agent model of urban systems

It is increasingly recognised that land use change processes are the outcome of decisions made by individual actors, such as land owners, authorities, firms and households. As multi-agent models provide a natural framework for modelling urban processes on the level of individual actors, Utrecht University, Eindhoven University of Technology and RIVM are developing PUMA (Predicting Urbanisation with Multi-Agents), a full fledged multi-agent system of urban processes. PUMA consists of various modules, representing the behaviours of specific actors. The land conversion module describes farmers', authorities', investors' and developers' decisions to sell or buy land and develop it into other uses. The households module describes households' housing careers in relation to life cycle events (marriage, child birth, aging, job change etc.). The firms module includes firms' demography and their related demand for production facilities leading to location choice processes. The daily activity pattern module describes the trips made and locations visited by individuals to carry out certain tasks. This module generates aggregated effects of individual behaviours (congestion, pollution, noise), affecting households' or firms' longer term location decisions. The paper describes the model system architecture and the interactions between the modules. Particular attention is devoted to the households module that includes a behaviourally sophisticated model of households' process of awakening (deciding to actively search for another dwelling), search and acceptance of an offered dwelling. This model was calibrated on the Dutch Housing Preferences Survey. Based on the disaggregate housing search and acceptance model, the households module describes housing market dynamics and indicates the demand for new dwellings per region. The paper describes the model specification and calibration in detail. The households module was implemented and tested for the Northwing of the Dutch Randstad, including about 1.5 million households and 1.6 million dwellings. The paper describes the implementation and the first model results