63 research outputs found

    Vegetation change in the Astrakhanskiy Biosphere Reserve (Lower Volga Delta, Russia) in relation to Caspian Sea level fluctuation

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    During the twentieth century the level of the Caspian Sea dropped from -26 m (1930) to -29 m (1977) below global sea level and subsequently rose again to -26.66 m in 1996. We aimed to describe responses of the vegetation in the lower Volga Delta to these substantial sea-level changes using an analysis of historic vegetation maps produced by aerial photography and satellite imagery. The sea level drop in the earlier part of the century was followed by rapid progression of the vegetation. The subsequent rapid sea-level rise in the 1980s did however not result in similarly rapid regression of the vegetation. This partial irreversibility of the vegetation response to sea-level change is explained by the wide flooding tolerance of the major emergent species, namely Phragmites australis. Floating vegetation increased in extent, most likely due to the increased availability of more favourable conditions, particularly for Nelumbo nucifera, a tropical plant reaching its northernmost distribution in the Volga Delta. This species increased in distribution from 3.5 ha in the 1930s throughout the entire Volga Delta to several thousands of hectares in the Astrakhanskiy Biosphere Reserve alone in the 1980s. The reported sea-level changes swept the ecosystems in the Astrakhanskiy Biosphere Reserve back and forth within the Reserve boundaries. At longer time scales, ten-fold greater sealevel change has been reported. The ecosystems for which the Reserve is renowned might be pushed completely out of the Reserve under these conditions. We therefore question whether the current Reserve will be sufficiently large to guarantee conservation of the biota in the lower Volga Delta at longer time scales

    Sensor Networks in the Low Lands

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    This paper provides an overview of scientific and industrial developments of the last decade in the area of sensor networks in The Netherlands (Low Lands). The goal is to highlight areas in which the Netherlands has made most contributions and is currently a dominant player in the field of sensor networks. On the one hand, motivations, addressed topics, and initiatives taken in this period are presented, while on the other hand, special emphasis is given to identifying current and future trends and formulating a vision for the coming five to ten years. The presented overview and trend analysis clearly show that Dutch research and industrial efforts, in line with recent worldwide developments in the field of sensor technology, present a clear shift from sensor node platforms, operating systems, communication, networking, and data management aspects of the sensor networks to reasoning/cognition, control, and actuation

    Field testing for toxic algae with a microarray: initial results from the MIDTAL project

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    One of the key tasks in the project MIDTAL (MIcroarrays for the Detection of Toxic ALgae) is to demonstrate the applicability of microarrays to monitor harmful algae across a broad range of ecological niches and toxic species responsible for harmful algal events. Water samples are collected from a series of sites used in national phytoplankton and biotoxin monitoring programmes across Europe. The samples are filtered; the rRNA is extracted, labelled with a fluorescent dye and applied to a microarray chip. The signal intensity from >120 probes previously spotted on the chip is measured and analysed. Preliminary results comparing microarray signal intensities with actual field counts are presented

    Field testing for toxic algae with a microarray: initial results from the MIDTAL project

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    One of the key tasks in MIDTAL (MIcroarrays for the Detection of Toxic ALgae) is to demonstrate the applicability of microarrays to monitor harmful algae across a broad range of ecological niches and toxic species responsible for harmful algal events. Water samples are collected from a series of sites used in national phytoplankton and biotoxin monitoring across Europe. The samples are filtered; rRNA is extracted, labelled with a fluorescent dye and applied to a microarray chip. The signal intensity from >120 probes previously spotted on the chip is measured and analysed. Preliminary results comparing microarray signal intensities with actual field counts are presented.Versión del edito

    Comparison between the performance of quantitative flow ratio and perfusion imaging for diagnosing myocardial ischemia

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    OBJECTIVES This study compared the performance of the quantitative flow ratio (QFR) with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion imaging (MPI) for the diagnosis of fractional flow reserve (FFR)-defined coronary artery disease (CAD).BACKGROUND QFR estimates FFR solely based on cine contrast images acquired during invasive coronary angiography (ICA). Head-to-head studies comparing QFR with noninvasive MPI are lacking.METHODS A total of 208 (624 vessels) patients underwent technetium -99m tetrofosmin SPECT and [15O]H2O PET imaging before ICA in conjunction with FFR measurements. ICA was obtained without using a dedicated QFR acquisition protocol, and QFR computation was attempted in all vessels interrogated by FFR (552 vessels).RESULTS QFR computation succeeded in 286 (52%) vessels. QFR correlated well with invasive FFR overall (R = 0.79; p < 0.001) and in the subset of vessels with an intermediate (30% to 90%) diameter stenosis (R = 0.76; p < 0.001). Overall, per-vessel analysis demonstrated QFR to exhibit a superior sensitivity (70%) in comparison with SPECT (29%; p < 0.001), whereas it was similar to PET (75%; p = 1.000). Specificity of QFR (93%) was higher than PET (79%; p < 0.001) and not different from SPECT (96%; p = 1.000). As such, the accuracy of QFR (88%) was superior to both SPECT (82%; p = 0.010) and PET (78%; p = 0.004). Lastly, the area under the receiver operating characteristics curve of QFR, in the overall sample (0.94) and among vessels with an intermediate lesion (0.90) was higher than SPECT (0.63 and 0.61; p < 0.001 for both) and PET (0.82; p < 0.001 and 0.77; p = 0.002), respectively.CONCLUSIONS In this head-to-head comparative study, QFR exhibited a higher diagnostic value for detecting FFRdefined significant CAD compared with perfusion imaging by SPECT or PET. (J Am Coll Cardiol Img 2020;13:1976-85) (c) 2020 by the American College of Cardiology Foundation.Cardiovascular Aspects of Radiolog

    Ascites door hypothyreoïdie

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    Contains fulltext : 25311___.PDF (publisher's version ) (Open Access

    Effects of trilostane treatment on the pituitary-adrenocortical and renin-aldosterone axis in dogs with pituitary-dependent hypercortisolism

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    Vet J. 2010 Jan;183(1):75-80. Epub 2008 Nov 29. Effects of trilostane on the pituitary-adrenocortical and renin-aldosterone axis in dogs with pituitary-dependent hypercortisolism. Galac S, Buijtels JJ, Mol JA, Kooistra HS. Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. [email protected] Abstract The medical records of 63 dogs with pituitary-dependent hypercortisolism (PDH) before and during treatment with trilostane were reviewed retrospectively. The correct trilostane dosage in dogs with PDH was based on the resolution of clinical signs and the results of an adrenocorticotropic hormone (ACTH) stimulation test. The mean (+/-SD) dose rate of trilostane to achieve good clinical control was 2.8+/-1.0mg/kg bodyweight. Trilostane treatment resulted in a significant decline in basal plasma cortisol concentrations. The median plasma ACTH concentration (39 pmol/L, range 7-132 pmol/L; n=60) at the optimal trilostane dosage time was significantly higher (

    Ascites door hypothyreoidie

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    Kloosters in Westerlauwers Friesland

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