Proportions,sums and ratios

Data that are proportions arise frequently in all areas of the sciences and engineering. In this paper, the exact distributions of R=X+Y and W=X/(X+Y) and the corresponding moment properties are derived when X and Y are proportions and arise from the most flexible bivariate beta distribution known to date. The associated estimation procedures are developed. Finally, an application is illustrated to compositional data of lavas from Skye.     

An online classification EM algorithm based on the mixture model

Mixture model-based clustering is widely used in many applications. In certain real-time applications the rapid increase of data size with time makes classical clustering algorithms too slow. An online clustering algorithm based on mixture models is presented in the context of a real-time flaw-diagnosis application for pressurized containers which uses data from acoustic emission signals. The proposed algorithm is a stochastic gradient algorithm derived from the classification version of the EM algorithm (CEM). It provides a model-based generalization of the well-known online k-means algorithm, able to handle non-spherical clusters. Using synthetic and real data sets, the proposed algorithm is compared with the batch CEM algorithm and the online EM algorithm. The three approaches generate comparable solutions in terms of the resulting partition when clusters are relatively well separated, but online algorithms become faster as the size of the available observations increases.     

Rethinking the nation and international relations: The space of nation states

Efforts to move sociology beyond the nation state and international relations theory have both been plagued by several limitations and dualisms. Recent research has begun to find ways beyond the problems by turning to Pierre Bourdieu's relational conception of social structure and practice. Yet one specific relational structure forming a key part of the puzzle has been neglected or merely implicitly assumed so far: the space of nation states. After clarifying the structural-constructivist nature of this concept, we aim to specify it by constructing an empirical model of the contemporary space of nation states using a specially compiled dataset and tools of geometric data analysis. The analysis reveals the distribution of powers on the world scene, and more specifically, the uneven possession of two varieties of “meta-capital” understood as capacities to regulate the value and exchangeability of certain capitals and to decree what even defines a legitimate “state”. We argue that the nation state, which is accurately understood as a contingent construct and well-founded fiction from a Bourdieusian viewpoint, should not be excluded when analyzing the expression and reproduction of contemporary global power relations.     

Lability of prenatal stress during the COVID-19 pandemic links to negative affect in infancy

The association between prenatal stress and children's socioemotional development is well established. The COVID-19 pandemic has been a particularly stressful period, which may impact the gestational environment. However, most studies to-date have examined prenatal stress at a single time point, potentially masking the natural variation in stress that occurs over time, especially during a time as uncertain as the pandemic. This study leveraged dense ecological momentary assessments from a prenatal randomized control trial to examine patterns of prenatal stress over a 14-week period (up to four assessments/day) in a U.S. sample of 72 mothers and infants. We first examined whether varied features of stress exposure (lability, mean, and baseline stress) differed depending on whether mothers reported on their stress before or during the pandemic. We next examined which features of stress were associated with 3-month-old infants' negative affect. We did not find differences in stress patterns before and during the pandemic. However, greater stress lability, accounting for baseline and mean stress, was associated with higher infant negative affect. These findings suggest that pathways from prenatal stress exposure to infant socioemotional development are complex, and close attention to stress patterns over time will be important for explicating these pathways.     

On distributions of exceedances associated with order statistics and record values for arbitrary distributions

Received: October 12, 1999; revised version: April 6, 2000     

Breaking down ideas and institutions: the politics of tax policy in the USA and the UK

As the existing comparative policy literature suggests, both ideational and institutional analyses have clear analytical value in their own terms but, under many circumstances, it is the combination of the two perspectives that allows for a full understanding of policy trajectories. In this article we suggest that, to improve our understanding of how ideas and institutions interact to produce change, it is important to break down these two overly broad concepts. This is because beyond general arguments about how ‘ideas’ and ‘institutions’ interact, students of public policy should itemize ‘ideas’ and ‘institutions’ into more focused, and empirically traceable, subcategories while recognizing the changing and contingent nature of their interaction, over time. To illustrate this, we turn to the politics of tax policy in the United States of America and the United Kingdom, tracking developments from the rise of the New Right and an aggressive income tax cutting agenda, personified by President Reagan and Prime Minister Thatcher, through to the revived debate about the legitimacy of increasing taxes on those earning the highest incomes that emerged in the era of austerity that followed the Great Recession of 2008.     

Racialisation and racial formation in urban spaces*

ABSTRACT

In this paper, I try to clarify the notions of racialisation and racial formation and how they operate in the framework of nation states like Brazil. My main argument is that these processes are always constrained by the formation of social classes and national cultural repertoires even if transnational forces are important in nurturing them. I conclude by making a preliminary effort to unravel mechanisms and institutions which allow these processes of racialisation and racial formation to form part of the daily lives of black Brazilians in the context of class-structured urban spaces.     

Educational optimism in China: migrant selectivity or migration experience?

This paper addresses the so-called paradox of immigrant optimism, which accounts for the higher educational expectations of immigrant–origin children, compared to non-immigrants in destination countries, conditional on social background and school attainment. We are interested in clarifying whether the mechanisms behind this optimism are related to migrant selectivity or family migration experience. To do this we use data from the China Education Panel Study, a representative survey of junior high school students in China. We use a two-pronged analytical strategy. Firstly, we look at whether having experienced family migration (within China) is associated with higher educational expectations. Secondly, we take a step back and explore whether adolescents who wish to migrate themselves when they grow up report higher educational expectations. Our findings confirm that adolescents who wish to migrate themselves when adults are already more optimistic even before any intentions of moving come to fruition. This we take as an indirect proof of selectivity. In contrast, we find no effect of family migration on expectations.     

Mortality by cause in the USSR in 1970–1987: the reconstruction of time series

This paper is the first step in an exploration of Soviet cause-of-death statistics which became accessible after 1986. Its main aim is the reconstruction of consistent annual series for the period 1970–1987 in spite of changes in cause-of-death classification caused by the 1980 revision of the Soviet nosological system. In a second part, the series thus reconstructed are analysed to describe the main features of the evolution of mortality during these two decades, using first standardized mortality rates for several very important specific causes and, second, using a method of decomposition of life expectancy changes. For the first time, trends in causes of death are thus shown for the crucial period where life expectancy has grown again after two decades of regression.Cet article constitue la première étape d'une exploration des statistiques soviétiques de décès par cause, devenues disponibles à partir de 1986. Il a pour principal objectif la reconstruction de séries annuelles cohérentes pour la période 1970–1987, en traitant les ruptures introduites par la révision de la Classification soviétique de 1980. La méthode utilisée pour ce faire est exposée dans la première partie. Dans une deuxième partie, les résultats ainsi obtenus permettent de décrire les grands traits de l'évolution de la mortalité au cours de ces deux décennies, d'abord sur la base de taux comparatifs de mortalité pour des causes spécifiques, puis grâce à une décomposition des variations de l'espérance de vie. Pour la première fois on peut ainsi suivre l'évolution des causes de décès dans une période déterminante au cours de laquelle, après deux décennies de recul, les progrès de l'espérance de vie ont repris.