The topographic evolution of the Tibetan Region as revealed by palaeontology

The Tibetan Plateau was built through a succession of Gondwanan terranes colliding with Asia during the Mesozoic. These accretions produced a complex Paleogene topography of several predominantly east–west trending mountain ranges separated by deep valleys. Despite this piecemeal assembly and resultant complex relief, Tibet has traditionally been thought of as a coherent entity rising as one unit. This has led to the widely used phrase ‘the uplift of the Tibetan Plateau’, which is a false concept borne of simplistic modelling and confounds understanding the complex interactions between topography climate and biodiversity. Here, using the rich palaeontological record of the Tibetan region, we review what is known about the past topography of the Tibetan region using a combination of quantitative isotope and fossil palaeoaltimetric proxies, and present a new synthesis of the orography of Tibet throughout the Paleogene. We show why ‘the uplift of the Tibetan Plateau’ never occurred, and quantify a new pattern of topographic and landscape evolution that contributed to the development of today’s extraordinary Asian biodiversity

Nutritional screening and assessment tools for older adults: literature review

Aim: This paper reports a literature review to examine the range of published tools available for use by nurses to screen or assess nutritional status of older adults, and the extent to which validity, reliability, sensitivity, specificity and acceptability of the tools has been addressed. Background: The incidence of malnutrition in older adults is high. One method by which malnutrition or risk of malnutrition can be detected is by the use of nutritional screening or assessment tools. Methods: A comprehensive literature review methodology was employed. A variety of electronic databases were searched for the period 1982-2002. Search terms incorporating nutrition, screening, validity, reliability and sensitivity and specificity were combined to retrieve relevant literature. In addition, manual searches were conducted and articles retrieved from those listed in key papers. In this paper, nutritional screening or assessment tools are described as tools which use a questionnaire-type format containing more than one risk factor for malnutrition, and give a quantitative or categorical assessment of risk. Results: Seventy-one nutritional tools were located, 21 of which were identified as designated for use with an older population. A wide variety of risk factors for malnutrition are used with the tools, ranging from objective measurements to subjective assessment. Some tools identify an action plan based on the score obtained. Many tools appear not to have been subjected to validity and/or reliability testing but are used clinically. Conclusion: As malnutrition is present in the older adult population, nutritional assessment and screening tools can be useful to highlight those in need of a nutritional care plan. However, many have not been subjected to evaluation and consequently may not demonstrate sensitivity and/or specificity in clinical use. The decision to use a particular tool should therefore be considered carefully