Search results for "Ice thickness"

Primary production calculations for sea ice from bio-optical observations in the Baltic Sea

2016

Abstract Bio-optics is a powerful approach for estimating photosynthesis rates, but has seldom been applied to sea ice, where measuring photosynthesis is a challenge. We measured absorption coefficients of chromophoric dissolved organic matter (CDOM), algae, and non-algal particles along with solar radiation, albedo and transmittance at four sea-ice stations in the Gulf of Finland, Baltic Sea. This unique compilation of optical and biological data for Baltic Sea ice was used to build a radiative transfer model describing the light field and the light absorption by algae in 1-cm increments. The maximum quantum yields and photoadaptation of photosynthesis were determined from 14C-incorporatio…

Exclusive MRI-based tandem and colpostats reconstruction in gynaecological brachytherapy treatment planning

2008

Purpose: According to the GYN GEC-ESTRO Recommendations, MRI is needed with the modality of T2 weighted. CT-MR compatible tandem Plus colpostats (T/C) (Nucletron) is widely used in cervical brachytherapy. The major challenge of MRI is the lack of dummy catheters. Therefore, an additional imaging modality is usually required. One disadvantage of sliced-based reconstruction is that resolution in longitudinal directions can be affected by the slice thickness. The aim of this study is to present a modified T/C applicator in which the catheter visibility is significantly improved. Methods and materials: A modification to the existing T/C applicator has been made available, increasing the cathete…

2009

Abstract. In-situ ice crystal size distribution measurements are presented within the tropical troposphere and lower stratosphere. The measurements were performed using a combination of a Forward Scattering Spectrometer Probe (FSSP-100) and a Cloud Imaging Probe (CIP), which were installed on the Russian high altitude research aircraft M55 "Geophysica" during the SCOUT-O3 campaign in Darwin, Australia. One of the objectives of the campaign was to characterise the Hector convective system, which appears on an almost daily basis during the pre-monsoon season over the Tiwi Islands, north of Darwin. In total 90 encounters with ice clouds, between 10 and 19 km altitude were selected from the dat…

Spiral-CT zum Nachweis von Koronararterienverkalkungen und Vorhersage einer koronaren Herzerkrankung - Vergleich zur Durchleuchtung und Koronarangiog…

1997

PURPOSE Evaluation of clinical relevance of coronary calcifications detected by helical CT. Evaluation of congruence with fluoroscopy (FS) and coronary angiography. Comparison with studies reporting on application of ultrafast computed tomography. MATERIALS AND METHODS 40 patients underwent helical CT (2 mm slice thickness, table-feed 3 mm/s). Coronary angiography and FS were performed in usual technique. Stenosis and calcifications were evaluated semiquantitatively. RESULTS 28 of 28 stenoses > or = 75% were detected via helical CT by evaluation of calcification (FS: 19). One non-detected solitary stenosis was calculated as 40%. FS did not detect 4 cases with 2-vessel and 3-vessel disease e…

Subglacial topography and thickness of ice caps on the Argentine Islands

2019

AbstractThis study presents the first subglacial topography and ice thickness models of the largest ice caps of the Argentine Islands, Wilhelm Archipelago, West Antarctica. During this study, ground-penetrating radar was used to map the thickness and inner structure of the ice caps. Digital surface models of all studied islands were created from aerial images obtained with a small-sized unmanned aerial vehicle and used for the construction of subglacial topography models. Ice caps of the Argentine Islands cover ~50% of the land surface of the islands on average. The maximum thickness of only two islands (Galindez and Skua) exceeds 30 m, while the average thickness of all islands is only ~5 …

Spiral-CT und 3 D-Rekonstruktion des Tracheobronchialbaumes zur Auswahl geeigneter Doppellumentuben vor Einzellungenbeatmung

1997

Purpose To assess the potential of 3-D spiral CT in the selection of adequate double-lumen tubes (DLT) for one-lung-ventilation. Materials and methods 3-D spiral CT of eight different DLTs was performed with standardized acquisition parameters: section thickness 4 mm, table speed 6 mm/s, increment 3 mm and standardised thresholds, window settings and magnification zoom. The accuracy was confirmed by measuring 3-D objects on screen and original DLTs by vernier caliper. 3-D spiral CT was performed in 20 patients preoperatively with slice thickness 4-8 mm, pitch 1-1.5, increment 4-8 mm. To select the adequate DLT size the 3-D reconstructions of the patient's tracheobronchial tree and of the DL…

Recent Change—Terrestrial Cryosphere

2015

This chapter compiles and assesses information on recent and current change within the terrestrial cryosphere of the Baltic Sea drainage basin. Findings are based on long-term observations. Snow cover extent (SCE), duration and amount have shown a widespread decrease although there is large interannual and regional variation. Few data are available on changes in snow structural properties. There is no evidence for a recent change in the frequency or severity of snow-related extreme events. There has been a decrease in glacier coverage in Sweden and glacier ice thickness in inland Scandinavia. The European permafrost is warming, and there has been a northward retreat of the southern boundary…

Visuelle Abschätzung der funktionellen Lungenanteile in der HRCT und 3He-MRT bei Patienten nach Einzel-Lungentransplantation: Vergleich mit der absol…

2005

Purpose: Visual assessment of the ventilation using HRCT and 3 He-MRI in patients after single lung transplantation (SLTX). Analysis of specific ventilation defects found with 3 He-MRI and morphological changes found with HRCT. Materials and Methods: We evaluated 8male patients (54 ′ 6 years) suffering from emphysema and six patients (3males and 3 females, 58 ′ 9.5 years) suffering from idiopathic pulmonary fibrosis (IPF) after SLTX. The morphological changes at HRCT were classified and localized. In 3 He-MRI (2D FLASH), 10 to 14 slices (slice thickness 10 mm, gap 5 mm) were acquired in coronal orientation to cover the whole lung. Ventilation defects were localized and characterized. The vi…

Quantifizierung von Atelektasen bei kontrollierter Beatmung: Spiral-CT versus dynamische Einzelschicht-CT

2004

Ziel: Dynamische CT-Untersuchungen (dCT) erlauben die Darstellung und Quantifizierung ventilierter Lungenflache und Atelektasenbildung wahrend kontinuierlicher Beatmung. Diese Studie ­vergleicht eine quantitative Auswertung einer infrakarinalen dCT-Einzelschicht mit der einer Spiral-CT der gesamten Lunge, um zu untersuchen, ob eine dynamisch gemessene Einzelschicht bezuglich der intrapulmonalen Atelektasenverteilung reprasentativ fur die Gesamtlunge ist. Material und Methoden: An 8 gesunden Schweinen erfolgte eine dCT (Schichtdicke 1 mm, zeitliches Inkrement 100 ms) wahrend kontinuierlicher Beatmung, gefolgt von einer Spiral-CT der gesamten Lunge (Schichtdicke 2 mm; Pitch 1,5; Inkrement 2 m…

Long-term changes of the ice regime of rivers in Latvia

2016

The ice regime of rivers is considered a sensitive indicator of climate change. This paper summarises the results of research on the long-term changes in the ice regime parameters under changing climate conditions and their regional peculiarities in Latvia from 1945 to 2012. The ice cover duration on Latvian rivers has decreased during recent decades. The research results demonstrated that there is a positive trend as regards the formation of the ice cover and in 31.8% of the cases the trend is statistically significant at p < 0.05. As regards the breaking up of ice, there is a statistically significant negative trend in 93.2% of the cases at p < 0.05. This indicates an earlie…