A review of mathematical functions for the analysis of growth in poultry

Poultry industries face various decisions in the production cycle that affect the profitability of an operation. Predictions of growth when the birds are ready for sale are important factors that contribute to the economy of poultry operations. Mathematical functions called ‘growth functions’ have been used to relate body weight (W) to age or cumulative feed intake. These can also be used as response functions to predict daily energy and protein dietary requirements for maintenance and growth (France et al., 1989). When describing growth versus age in poultry, a fixed point of inflexion can be a limitation with equations such as the Gompertz and logistic. Inflexion points vary depending on age, sex, breed and type of animal, so equations such as the Richards and López are generally recommended. For describing retention rate against daily intake, which generally does not exhibit an inflexion point, the monomolecular would appear the function of choice

Learning from, through and about Differences: A Multiple Case Study on Schools as Practice Grounds for Citizenship

Learning to relate to others that differ from you is one of the central aims of citizenship education. Schools can be understood as practice grounds for citizenship, where students’ citizenship is not only influenced by the formal curriculum, but also by their experiences in the context of teacher-student and student-student relations. In this article we therefore investigate: How is the practice of dealing with difference enacted in schools? Data were collected through an exploratory multiple case study in four secondary schools, combining interviews and focus groups. Despite the differences between the schools in terms of population and location, in all schools ‘being different’ was understood primarily in relation to other students within the school. Relevant differences for citizenship were confined to ‘ethnic and cultural diversity’. Furthermore, in all schools there was limited reflection on being different in relation to the broader community. This article calls for preparing teachers to consider a broader array of differences to practice dealing with differences with their students and to support students in reflecting on the societal implications of being different from each other