Estimation of Hazard, Density and Survivor Functions for Randomly Censored Data

Maximum likelihood estimation and goodness-of-fit techniques are used within a competing risks framework to obtain maximum likelihood estimates of hazard, density, and survivor functions for randomly right-censored variables. Goodness-of- fit techniques are used to fit distributions to the crude lifetimes, which are used to obtain an estimate of the hazard function, which, in turn, is used to construct the survivor and density functions of the net lifetime of the variable of interest. If only one of the crude lifetimes can be adequately characterized by a parametric model, then semi-parametric estimates may be obtained using a maximum likelihood estimate of one crude lifetime and the empirical distribution function of the other. Simulation studies show that the survivor function estimates from crude lifetimes compare favourably with those given by the product-limit estimator when crude lifetimes are chosen correctly. Other advantages are discussed.     

BUILDING THE EVIDENCE BASE FROM LONGITUDINAL DATA

Survey data from cross-sectional snapshots give an incomplete picture of the social fabric. Without longitudinal information, planners, practitioners, social scientists and policy makers would be in the dark about dynamics, durations and pathways of human development. Longitudinal data collected in birth cohort studies give a better guide to long-term processes and outcomes and are more informative about the causal relations that are the drivers of disadvantage or success. The content and structure of Britain's Birth Cohort Studies are described to illustrate the challenges of creating and studying longitudinal evidence. Examples of findings and policies based on these prospective longitudinal studies are given, along with a discussion of the practical decisions that have to be confronted in undertaking them.     

Neither ‘family’ nor ‘corporate’ farming: Australian tomato growers as farm family entrepreneurs

For the past two decades there has been much debate about the future of family farming. The basic question on which this debate has turned is whether current pressures on family farm systems should be understood as symptomatic of a terminal condition, in which farmers are replaced progressively by corporate ownership; or whether family farms will persist as a social formation, albeit increasingly subsumed by off-farm interests. Using evidence from the Australian processing tomato sector, this article documents the changing social and economic formation of ‘family farming’. We argue that in this industry, the appropriate way to describe farmers is through the deployment of that a new category of farming; farm family entrepreneurs. This phrase is coined to describe the situation where family units remain at the social and economic heart of farm ownership and operation, but in the context where they relate to their land-based assets through legal and financial structures characteristic of the wider economy. As this article explores, this formation seems to represent an accommodating modus operandi for farm units within neo-liberal agricultural governance. Nevertheless, however, this duality of family-based structures and capitalist entrepreneurialism inevitably provokes a series of tensions, whose resolution requires a variety of organizational strategies to be put in place.     

From critical sociology to public intellectual: Pierre Bourdieu and politics

By the late 1990s, Pierre Bourdieu had become the primary public intellectual of major social scientific status at the head of the anti-globalization movement that emerged in France and in other Western European countries. This article discusses how Bourdieu became a leading public intellectual, a role that seems to contrast with his early years as a professional sociologist. It explores what seemed to change in Bourdieu’s activities and outlook as sociologist and what seems to have remained constant. It identifies several institutional conditions that seemed necessary for Bourdieu to be able to play the kind of public intellectual role he did in his later years. Bourdieu’s movement from a peripheral position to a central location in the French intellectual field, the changing character of the field itself, the growing influence of the mass media in French political and cultural life, the failures of the French Socialists in power, a cultural legacy of leading critical intellectuals in France, a unifying national issue of globalization, and the political conjuncture in 1995 all intersected in ways that opened a path for Bourdieu to choose new and more frequent forms of political action. His responses to that combination of factors at different moments reveal both a striking continuity in desire to preserve the autonomy of intellectual life and a change in view and strategy on how best to do that. The article concludes with a brief evaluation of Bourdieu’s public intellectual role.     

Risk Compensation or Risk Reduction? Seatbelts,State Laws,and Traffic Fatalities*

Objective. The risk compensation hypothesis suggests that drivers enjoying greater safety will drive more recklessly and thereby impose greater risks on nonoccupants. We provide a test of the risk compensation hypothesis in the context of state seatbelt laws and belt use rates. Methods. Fixed‐effects models with policy and demographic variables are estimated using annual state data from 1985 to 2002 to test the effect of seatbelt laws and seatbelt use rates on logged fatality rates for occupants, pedestrians, motorcyclists, and all nonoccupants in separate models. Results. Contrary to the risk compensation hypothesis, the results indicate that both occupants and nonoccupants enjoy greater safety due to state mandatory use laws and increased safety belt use rates. Conclusion. Overall, seatbelt laws and the higher belt use these laws induce do not increase nonoccupant risk exposure. If anything, these laws and the accompanying increase in belt use result in safer driving behavior.     

Refugee Children in Wales: Coping and Adaptation in the Face of Adversity

This article aims to makes a contribution to redressing a methodological and theoretical imbalance in existing research on refugee and asylum‐seeking children. It draws on two qualitative studies from Wales with children and young people. The samples include unaccompanied minors and children living with families as well as both children who are supported in the asylum system and those who have been granted refugee status. The focus on ecological post‐migratory stressors and coping processes that young people identify as being integral to their well‐being and, once granted status, to how they adapt to settlement includes a selective study of some of the sources of resilience referred to in the children's talk. Recognising the interplay between individual and environment leads to a discussion of both personal attributes and collective cultural identities.     

Quantifying uncertainty in the biospheric carbon flux for England and Wales

Summary.  A crucial issue in the current global warming debate is the effect of vegetation and soils on carbon dioxide (CO₂) concentrations in the atmosphere. Vegetation can extract CO₂ through photosynthesis, but respiration, decay of soil organic matter and disturbance effects such as fire return it to the atmosphere. The balance of these processes is the net carbon flux. To estimate the biospheric carbon flux for England and Wales, we address the statistical problem of inference for the sum of multiple outputs from a complex deterministic computer code whose input parameters are uncertain. The code is a process model which simulates the carbon dynamics of vegetation and soils, including the amount of carbon that is stored as a result of photosynthesis and the amount that is returned to the atmosphere through respiration. The aggregation of outputs corresponding to multiple sites and types of vegetation in a region gives an estimate of the total carbon flux for that region over a period of time. Expert prior opinions are elicited for marginal uncertainty about the relevant input parameters and for correlations of inputs between sites. A Gaussian process model is used to build emulators of the multiple code outputs and Bayesian uncertainty analysis is then used to propagate uncertainty in the input parameters through to uncertainty on the aggregated output. Numerical results are presented for England and Wales in the year 2000. It is estimated that vegetation and soils in England and Wales constituted a net sink of 7.55 Mt C (1 Mt C = 10¹² g of carbon) in 2000, with standard deviation 0.56 Mt C resulting from the sources of uncertainty that are considered.     

Risk management: a general framework for rural development

This paper proposes a new concept of rural development in an uncertain world. The nature of risk and uncertainty is discussed and risk management is defined as a positive model of economic and social behaviour. Some relevant paradigms for rural development are reviewed and evaluated within the general approach of risk management. It is demonstrated that the proposed view of risk management can effectively combine and reconcile different approaches by highlighting their advantages and shortcomings. Departing from a subjective definition of risk management, we progressively include its social dimensions which introduce both complexity and structure into the process of rural development.