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- Tetzlaff, D., et al.
(författare)
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How does landscape structure influence catchment transit time across different geomorphic provinces?
- 2009
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 23:6, s. 945-953
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Tidskriftsartikel (refereegranskat)abstract
- Despite an increasing number of empirical investigations of catchment transit times (TTs), virtually all are based on individual catchments and there are few attempts to synthesize understanding across different geographical regions. Uniquely, this paper examines data from 55 catchments in five geomorphic provinces in northern temperate regions (Scotland, United States of America and Sweden). The objective is to understand how the role of catchment topography as a control on the TTs differs in contrasting geographical settings. Catchment inverse transit time proxies (ITTPs) were inferred by a simple metric of isotopic tracer damping, using the ratio of standard deviation of delta O-18 in streamwater to the standard deviation of delta O-18 in precipitation. Quantitative landscape analysis was undertaken to characterize the catchments according to hydrologically relevant topographic indices: that could be readily determined from a digital terrain model (DTM). The nature of topographic controls on transit times varied markedly in different geomorphic regions. In steeper montane regions. there are stronger gravitational influences on hydraulic gradients and TTs tend to he lower in the steepest catchments. In provinces where terrain is more subdued, direct topographic control weakened; in particular, where flatter areas with less permeable soils give rise to overland How and lower The steeper slopes within this flatter terrain appear to have a greater coverage of freely draining soils, which increase sub-surface flow, therefore increasing TTs. Quantitative landscape analysis proved a useful tool for intercatchment comparison. However, the critical influence of sub-surface permeability and connectivity may limit the transferability of predictive tools of hydrological function based on topographic parameters alone. Copyright (C) 2009 John Wiley & Sons, Ltd.
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- Simonsen, A. H., et al.
(författare)
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A novel panel of cerebrospinal fluid biomarkers for the differential diagnosis of Alzheimer's disease versus normal aging and frontotemporal dementia
- 2007
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 24:6, s. 434-440
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: An early and accurate diagnosis of Alzheimer's disease (AD) is important in order to initiate symptomatic treatment with currently approved drugs and will be of even greater importance with the advent of disease-modifying compounds. METHODS: Protein profiles of human cerebrospinal fluid samples from patients with AD (n = 85), frontotemporal dementia (n = 20), and healthy controls (n = 32) were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry to verify previously discovered biomarkers. RESULTS: We verified 15 protein biomarkers that were able to differentiate between AD and controls, and 7 of these 15 markers also differentiated AD from FTD. CONCLUSION: A panel of cerebrospinal fluid protein markers was verified by a proteomics technology which may potentially improve the accuracy of the AD diagnosis.
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