Incorporation of historical controls using semiparametric mixed models

The analysis of animal carcinogenicity data is complicated by various statistical issues. A topic of recent debate is how to control for the effect of the animal's body weight on the outcome of interest, the onset of tumours. We propose a method which incorporates historical information from the control animals in previously conducted experiments. We allow non-linearity in the effects of body weight by modelling the relationship nonparametrically through a penalized spline. A simple extension of the penalized spline model allows the relationship between weight and the onset of tumour to vary from one experiment to another.     

Error variance bias in neighbour balance and evenness of distribution designs

Neighbour balance and evenness of distribution designs help to address user concerns in the two‐dimensional layout of agricultural field trials. This is done by minimising the occurrence of pairwise treatment plot neighbours and ensuring that the replications of treatments are spread out across rows and columns of a trial. Such considerations result in a restriction on the normal randomisation process for a row‐column design which can lead to error variance bias. In this paper, uniformity trial data is used to assess the degree of this bias for both resolvable and non‐resolvable designs. Comparisons are made with a similar investigation using Linear Variance spatial designs.     

Object detection in multi-epoch data

In astronomy multiple images are frequently obtained at the same position of the sky for follow-up coaddition as it helps one go deeper and look for fainter objects. With large scale panchromatic synoptic surveys becoming more common, image co-addition has become even more necessary as new observations start to get compared with coadded fiducial sky in real time. The standard coaddition techniques have included straight averages, variance weighted averages, medians etc. A more sophisticated nonlinear response chi-square method is also used when it is known that the data are background noise limited and the point spread function is homogenized in all channels. A more robust object detection technique capable of detecting faint sources, even those not seen at all epochs which will normally be smoothed out in traditional methods, is described. The analysis at each pixel level is based on a formula similar to Mahalanobis distance.     

Life As Gift: Spiritual Narratives of Elderly African-American Women Living in Poverty

Fifty elderly African-American women living in poverty were interviewed for a research project entitled, “Chronic Poverty and the Self in Later Life.” Using four representative case studies from the 50 respondents, this article explores how their spirituality informs their ability to cope with poverty. A key theme emerging from the women's narratives is that their relationship with God, perceived as personal, reciprocal, and empowering, allows them to take an active and positive stance in viewing and interpreting the circumstances of their life. Their spirituality imbues their hardship with meaning, engenders self-esteem, keeps despair at bay, and grants hope for rewards both in this life and the next.     

What skills do physician leaders need now and in the future?

The role of the physician leader is moving beyond traditional medical staff issues. A recent national survey of physician leaders shows a growing need for education on specific technical, leadership, and practical skills. The results reveal the medical leadership skills that physician executives consider important today, and provide a window to the future about the skills that will be important tomorrow. Physicians say they need training now in quality assurance, clinical benchmarking, decision-making, and strategic planning. And when they gaze into the future and see the rapid changes throughout health care, they say they'll need more training in communication, organizational change, effective listening, and systems thinking.