Creating reusable well-structured pdf as a sequence of component object graphic (cog) elements

Portable Document Format (PDF) is a page-oriented, graphically rich format based on PostScript semantics and it is also the format interpreted by the Adobe Acrobat viewers. Although each of the pages in a PDF document is an independent graphic object this property does not necessarily extend to the components (headings, diagrams, paragraphs etc.) within a page. This, in turn, makes the manipulation and extraction of graphic objects on a PDF page into a very difficult and uncertain process. The work described here investigates the advantages of a model wherein PDF pages are created from assemblies of COGs (Component Object Graphics) each with a clearly defined graphic state. The relative positioning of COGs on a PDF page is determined by appropriate "spacer" objects and a traversal of the tree of COGs and spacers determines the rendering order. The enhanced revisability of PDF documents within the COG model is discussed, together with the application of the model in those contexts which require easy revisability coupled with the ability to maintain and amend PDF document structure.

Doctors' thinking about the system as a threat to patient safety

‘Systems thinking’ is an important feature of the emerging ‘patient safety’ agenda. As a key component of a ‘safety culture’, it encourages clinicians to look past individual error to recognise the latent factors that threaten safety. This paper investigates whether current medical thinking is commensurate with the idea of ‘systems thinking’ together with its implications for policy. The findings are based on qualitative semistructured interviews with specialist physicians working within one NHS District General Hospital in the English Midlands. It is shown that, rather then favouring a 'person-centred’ perspective, doctors readily identify ‘the system’ as a threat to patient safety. This is not necessarily a reflection of the prevailing safety discourse or knowledge of policy, but reflects a tacit understanding of how services are (dis)organised. This line of thinking serves to mitigate individual wrong-doing and protect professional credibility by encouraging doctors to accept and accommodate the shortcomings of the system, rather than participate in new forms of organisational learning.