The properties of electron transport through CNT/trans-PA/CNT system

Abstract Using a tight-binding model and a tranfer-matrix technique, we numerically investigate the effects of the coupling strength, and the length of the molecule on the electronic transmission through a CNT/(single) molecule/CNT system. With trans-polyacetylene (trans-PA) as the molecule sandwiched between two semi-infinite carbon nanotube(CNT), we rely on Landauer formalism as the basis for studying the conductance properties of this system. Our calculations show that the conductance is sensitive to the CNT/molecule coupling and that it exponentially decreases with the increase in the length of the molecule, as expected

A longitudinal analysis of poverty among families supporting a child with disability

This paper addresses the relation between poverty and the presence of a child with a disability in the family, using longitudinal data from a secondary source. Two main issues are considered. First, to assess the degree to which explanatory variables influence poverty, an adequate statistical model must handle the possibility that substantial variation between respondents will be owing to omitted variables, multicollinearity and past behaviour. Second, research often compares ‘‘no poverty’’ with ‘‘presence of poverty’’. We acknowledge that there could be differences between those in moderate poverty and those in severe poverty which might provide additional insights into the relation between ‘‘child disability in the family’’ and ‘‘poverty’’. A multinomial random effects model is fitted to the data. The results suggest that the distinction between moderate and severe poverty appears to improve the results. Further improvement could be achieved by a clear definition of poverty and disability and of observed variables included in the analysis

Statistical modelling of dependency in old age

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN007228 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Conceptualizing Behaviour in Health and Social Research: A Practical Guide to Data Analysis

The emphasis in this book is not on mathematics of statistics nor is it on technical aspects or statistical assumptions. These are discussed in numerous books and relevant journals. The emphasis in this book is to unpackage statistical thinking. This is done through anticipation and expectation of difficult issues in real life examples and ways of dealing with them as they arise. It is intended to illustrate the application of statistical concepts in order to gain insight into the subject under investigation by appropriate development of the cognitive aspects of research. There are many instances when the appropriate statistical method is applied to the data yet the results may be erroneous leading to misleading conclusions. This is a very serious consequence, particularly in an environment where evidence-based practice has been encouraged. This book attempts to encourage a discussion of the main substantive issues and how they may have an impact on the statistical methodology and the interpretation of results. The authors hope to have provided some motivation to promote the practice and adoption of analytical methods that allow for statistical control