Fitting and comparing seed germination models with a focus on the inverse normal distribution

This paper reviews current methods for fitting a range of models to censored seed germination data and recommends adoption of a probability‐based model for the time to germination. It shows that, provided the probability of a seed eventually germinating is not on the boundary, maximum likelihood estimates, their standard errors and the resultant deviances are identical whether only those seeds which have germinated are used or all seeds (including seeds ungerminated at the end of the experiment). The paper recommends analysis of deviance when exploring whether replicate data are consistent with a hypothesis that the underlying distributions are identical, and when assessing whether data from different treatments have underlying distributions with common parameters. The inverse normal distribution, otherwise known as the inverse Gaussian distribution, is discussed, as a natural distribution for the time to germination (including a parameter to measure the lag time to germination). The paper explores some of the properties of this distribution, evaluates the standard errors of the maximum likelihood estimates of the parameters and suggests an accurate approximation to the cumulative distribution function and the median time to germination. Additional material is on the web, at http://www.agric.usyd.edu.au/staff/oneill/ .     

Lesbian Parenting: Insiders' Voices

Lesbian parenting has entered the public arena over recent years via debates regarding access to fertility services and adoption, legal recognition of same‐sex parents and children's rights (McNair, 2002). Research in the area has been published for over 20 years, with an increasing shift towards delineating diversity rather than proving the legitimacy of these families. The ANZJFT — the major mouthpiece for Australian family therapists — has made curiously little contribution to the literature on lesbian parenting. The lack of discussion leaves trainees and family therapists largely ignorant about the lived experience of lesbian family life. This paper goes some way to filling this gap. We present data gathered from 151 Australian lesbian parents who answered questions about their own and their families' perceived strengths. Despite the constraints and challenges of living within a heteronormative and homophobic society and dealing with discrimination and legal, political and social non‐legitimation, this group of lesbian parents expressed great pride in raising well‐adjusted and happy children. They also described their families as thoughtfully planned, proud, accepting and celebratory of diversity and difference, flexible in gender roles, and as having interesting, supportive, extended kinship networks that included a wide range of positive role models for their children.     

Research provides golden opportunity for physicians. An overview of clinical trials and how to conduct them.

Conducting clinical trials at your practice can help you increase your medical knowledge, allow you to contribute to valuable scientific study, and create a new revenue stream. Take a look at how to get involved in clinical research.