Orientation studies of waterlogged wood: A paleocurrent indicator?

Fossil wood has been used extensively as a paleocurrent indicator, and published evidence suggests that it may be aligned either parallel or perpendicular to a unidirectional current. Flume experiments on deposition of waterlogged wood show that most fragments are aligned parallel to the current. For fragments with a high degree of symmetry, however, a perpendicular orientation is possible. The dominant factors in controlling the orientation of wood fragments appear to be current velocity, fragment shape and fragment size

A Delay Differential Model for Pandemic Influenza with Antiviral Treatment

The use of antiviral drugs has been recognized as the primary public health strategy for mitigating the severity of a new influenza pandemic strain. However, the success of this strategy requires the prompt onset of therapy within 48 hours of the appearance of clinical symptoms. This requirement may be captured by a compartmental model that monitors the density of infected individuals in terms of the time elapsed since the onset of symptoms. We show that such a model can be expressed by a system of delay differential equations with both discrete and distributed delays. The model is analyzed to derive the criterion for disease control based on two critical factors: (i) the profile of treatment rate; and (ii) the level of treatment as a function of time lag in commencing therapy. Numerical results are also obtained to illustrate the feasible region of disease control. Our findings show that due to uncertainty in the attack rate of a pandemic strain, initiating therapy immediately upon diagnosis can significantly increase the likelihood of disease control and substantially reduce the required community-level of treatment. This suggests that reliable diagnostic methods for influenza cases should be rapidly implemented within an antiviral treatment strategy

Improving understanding and rigour through triangulation: An exemplar based on patient participation in interaction

Aim: In this paper, we aim to explore the benefits of triangulation and to expose the positive contribution of using 'triangulation for completeness' within a study of a complex concept, namely patient participation during healthcare interaction. Background: Complex concepts, such as patient participation, are often the focus of nursing research. Triangulation has been proposed as a technique for studying complexity but, although debates about triangulation are becoming more prevalent in the literature, there is little deliberation about the process through which triangulation for completeness, with its claims of forming more comprehensive and rigorous descriptions of concepts through use of multiple data sources, yields it purported benefits. Methods: A seminar series, held between 2001 and 2003, brought together researchers actively involved in the study of patient participation in healthcare consultations. The group came from diverse methodological traditions and had undertaken research with a range of informants and a range of methods. Discussion: The various studies used triangulation at different levels: within studies, across studies and across disciplines. Our examples support theoretical arguments that triangulation for completeness can lead to a more holistic understanding of a concept and can improve scientific rigour. Furthermore, we suggest that triangulation can improve research skills for individuals. Our examples suggest that the process through which understanding is enhanced is discursive and centres on discussions of convergent and unique findings; rigour is improved is through challenging findings, being encouraged to explain aspects of your research that may be taken for granted and improving transparency; and individual researcher's skills and abilities are improved is through a process of discussion and reflexivity. Conclusions: Triangulation for completeness, on various levels, can improve the quality and utility of research about complex concepts through a range of discursive processes. Developing greater opportunity to collaborate at various levels of analysis could be an important development in nursing research