1,720,978 research outputs found
A cost valuation model based on a stochastic representation of the IPAT equation
No full textWithin the framework of models for human-driven environmental impact based on the IPAT equation, we develop a model for the evolution of impact (expressed in terms of carbon dioxide emissions) and for the valuation of the economic cost associated to its reduction. We use a stochastic representation of the IPAT equation that is alternative to the STIRPAT model. This first step leads to a stochastic differential equations model that describes trends in carbon dioxide emissions on the basis of economic and demographic dynamics. As an example, we estimate the model parameters for the United States. We then use this framework to build a model for the assessment of the economic costs related to a reduction of carbon dioxide emissions for a country committed to respect an international agreement, such as the Kyoto protocol. In particular, we show that the adherence to an environmental treaty may be traced back to a problem of cost valuation and to a decision under risk. This allows us to use the mathematical tools that have been developed in quantitative finance, in the context of option pricing, to determine the expected investment that is required to reduce the emissions of a country by a certain amount and within a well-defined temporal frame. © Springer Science+Business Media, LLC 2008
Migration to urban and rural destinations in post-Soviet Estonia: A multilevel event-history analysis
No full textResearchers are divided on the trends and causes of internal migration in postsocialist Central and Eastern Europe. Theories run in opposite directions: some scholars argue that increasing similarities with Western market economies are explaining the migration processes, whereas others claim that specific developments during the postsocialist socioeconomic restructuring are playing a major role. In this paper we contribute to the existing discussion by providing an analysis of personal and contextual determinants of migration to urban and rural destinations in post-Soviet Estonia. We base our study on the data of the Estonian Labour Force Survey from 1995. Our research population consists of 8480 people aged 15 years to 68 years in early 1989. We analyze the intensity of urban-bound and rural-bound migration from January 1989 to December 1994, using the techniques of multilevel event-history analysis. We show that personal characteristics (age, marital status, employment status, education, and ethnicity) and contextual factors (unemployment level and the share of ethnic minorities) are both important in shaping the intensity of migration to urban and rural destinations in post-Soviet Estonia. Although the differences in migration behaviour by demographic characteristics in Estonia are in line with universalistic explanations, the regionally varying effect of socioeconomic status on migration is specific to developments in postsocialist countries, as a result of general economic hardship during the socioeconomic transition. © 2006 a Pion publication printed in Great Britain
Classifying life course trajectories: a comparison of latent class and sequence analysis
No full textMultilevel analysis of internal migration in a transitional country: the case of Estonia
No full textRecent geographical migration studies have aimed at clarifying the impact of both social environment and people's desires and beliefs on migration behaviour. However, most studies have focused on migration in Western countries, using cross-sectional data and single level methods. In this paper, we study the determinants of internal migration in Estonia, a multicultural society, during the transition period (1989-1994). We use longitudinal data and apply multilevel event history methods. We show that both personal and contextual (potentially time-varying) factors are important in determining migration propensity. Moreover, several personal determinants - age, employment status, ethnic origin - interact with environmental conditions in shaping behaviour. While our results of the age differences support a traditional life-course related migration pattern, our results of the differences in migration behaviour by employment status and ethnic origin imply deepening social polarization and ethnic segregation in the post-Soviet Estonia as a result of internal migration
Aggregate age-at-marriage patterns from individual mate-search heuristics
No full textThe distribution of age at first marriage shows well-known strong regularities across many countries and recent historical periods. We accounted for these patterns by developing agent-based models that simulate the aggregate behavior of individuals who are searching for marriage partners. Past models assumed fully rational agents with complete knowledge of the marriage market; our simulated agents used psychologically plausible simple heuristic mate search rules that adjust aspiration levels on the basis of a sequence of encounters with potential partners. Substantial individual variation must be included in the models to account for the demographically observed age-at-marriage patterns
Social age deadlines for the childbearing of women and men
Full text linkThis study examines whether social age deadlines exist for childbearing in women and men, how they vary across countries, whether they are lower than actual biological deadlines and whether they are associated with childbearing at later ages and the availability of assisted reproduction techniques (ARTs).
This study is based on the European Social Survey, Round 3 (2006–2007), which covers 25 countries. Data were gathered on social age deadlines for childbearing in women (21 909 cases) and men (21 239 cases) from samples of representative community-dwelling
populations aged 15 and older.
results: sociial age deadlines for childbearing were perceived more frequently for women than men. These deadlines are often lower than actual biological limits, and for women and men alike: 57.2% of respondents perceived a maternal social age deadline ≤40 years of age; 46.2% of the respondents perceived a paternal social age deadline ≤45 years of age. There is also considerable variability in deadlines across countries, as well as within them. At the country level, the presence of social age deadlines for the childbearing of women was negatively associated with birth rates at advanced ages and the prevalence of ART, and later deadlines were positively associated with these factors.
conclusions: It is important to understand the factors that increase and limit late fertility. While biological factors condition fertility, so do social expectations. These findings provide widespread evidence across Europe that social limits exist alongside biological ones, though both sets of factors are more binding for women.
keywords: maternal age; paternal age; life course; fertility; assisted reproductive technology
Diffusion processes in demographic transitions:A prospect on using multi agent simulation to explore the role of cognitive strategies and social interactions
No full textMulti agent simulation (MAS) is a tool that can be used to explore the dynamics of different systems. Considering that many demographic phenomena have roots in individual choice behaviour and social interactions it is important that this behaviour is being translated in agent rules. Several behaviour theories are relevant in this context, and hence there is a necessity of using a meta-theory of behaviour as a framework for the development of agent rules. The consumat approach provides a basis for such a framework, as is demonstrated with a discussion of modelling the diffusion of contraceptives. These diffusion processes are strongly influenced by social processes and cognitive strategies. Different possible research lines are discussed which might be addressed with a multi-agent approach like the consumats.</p
Diffusion processes in demographic transitions:A prospect on using multi agent simulation to explore the role of cognitive strategies and social interactions
No full textMulti agent simulation (MAS) is a tool that can be used to explore the dynamics of different systems. Considering that many demographic phenomena have roots in individual choice behaviour and social interactions it is important that this behaviour is being translated in agent rules. Several behaviour theories are relevant in this context, and hence there is a necessity of using a meta-theory of behaviour as a framework for the development of agent rules. The consumat approach provides a basis for such a framework, as is demonstrated with a discussion of modelling the diffusion of contraceptives. These diffusion processes are strongly influenced by social processes and cognitive strategies. Different possible research lines are discussed which might be addressed with a multi-agent approach like the consumats.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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