Modelling the diameter distribution of forest stands using the Burr distribution

SUMMARY For the past 20 years, forest modellers have largely used the Weibull distribution to summarize diameter distributions and to predict timber volume in a forest at clearfell time. The wider family of Burr distributions is investigated here as an alternative to the Weibull distribution. Using data from 20 permanent sample plots of Pinus radiata, we compare Burr and Weibull fits, showing that the Burr distribution enhances precision by roughly 13 . The effectiveness of the Burr distribution for prediction is found to be similar to that of the Weibull distribution.     

Making something of the sacrifice: gender,migration and Mexican children's educational aspirations

Transnational families often use international migration as a strategy not only for survival, but also for social mobility. Migrant parents hope their sacrifices via migration will translate into educational benefits for non‐migrant children. In this article, we use mixed methods to explore the success of parents' efforts by considering the relationship between gender, family migration patterns and the educational aspirations of children in the Mixteca region of Mexico. Analysis of surveys collected from 1273 students show that mothers' migrations affect children's educational goals in different ways depending on whether they migrate alone or with their husbands. Fathers' lone migrations have no significant impact on children's educational aspirations. Interviews with 51 children of migrants suggest that children of unmarried migrant mothers are motivated academically because they invest in their mothers' migrations as a sacrifice, whereas the emotional consequences of parental absences lower the educational aspirations of children with both parents in the USA.     

Parental involvement in reading: the influence of socio-economic status and supportive home visiting

SUMMARY: This paper describes the deployment of the technique for non-professional tutoring of reading known as ‘paired reading’ on a large scale in the Kirklees Local Education Authority. From the very large amount of data generated in multi-site field trials, particular attention is focused on the relationship between supportive home visiting (if any), an index of the socioeconomic disadvantage of the catchment area of each participating school, and outcomes in term of gains on norm-referenced tests of reading. Some surprising conclusions emerge.     

Socioeconomic Status and Body Mass Index in Canada: Exploring Measures and Mechanisms

We examine the relationship between socioeconomic status (SES), sociodemographic characteristics, lifestyle behaviors (fruit and vegetable intake, exercise, smoking, and alcohol consumption), and body mass index (BMI) using the Canadian Community Health Survey 2.1. We explore two different measures of SES, education and income, to elucidate material and cultural explanations of the SES‐BMI relationship. Results vary significantly by gender, highlighting the complexity of the relationship between SES, sociodemographic and lifestyle factors, and BMI. We suggest that body weight is still a gendered status symbol, and that cultural and psychosocial factors may be more important than material factors in perpetuating this health inequality.