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- Wassélius, Johan, et al.
(författare)
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Treatment of mesenteric vein thrombosis with transjugular mechanical thrombectomy and subsequent simultaneous arterial and venous thrombolysis
- 2014
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Ingår i: Journal of Vascular Surgery: Venous and Lymphatic Disorders. - : Elsevier BV. - 2213-333X. ; 2:3, s. 3-320
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Tidskriftsartikel (refereegranskat)abstract
- Mesenteric vein thrombosis may induce intestinal ischemia and gangrene. In severe cases, it is necessary to restore venous outflow from the small intestine rapidly. We describe a severe case of mesenteric vein thrombosis that was resolved successfully by mechanical thrombectomy from a transjugular approach followed by selective simultaneous venous and arterial thrombolysis via the superior mesenteric vein and artery. In conclusion, the transjugular intrahepatic portosystemic approach was a feasible and safe access for mechanical thrombectomy and thrombolysis of the mesenteric vein in our patient.
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| 3. |
- Fors, Carina, et al.
(författare)
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Camera-based sleepiness detection : final report of the project SleepEYE
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Two literature reviews were conducted in order to identify indicators of driver sleepiness and distraction. Three sleepiness indicators – blink duration, blink frequency and Perclos – were implemented in the camera system.The aims of the study were firstly to develop and evaluate a low cost 1-camera unit for detection of driver impairment, and secondly to identify indicators of driver sleepiness and to create a sleepiness classifier for driving simulators.The project included two experiments. The first was a field test where 18 participants conducted one alert and one sleepy driving session on a motorway. 16 of the 18 participants also participated in the second experiment which was a simulator study similar to the field test.The field test data was used for evaluation of the 1-camera system, with respect to the sleepiness indicators. Blink parameters from the 1-camera system was compared to blink parameters obtained from a reference 3-camera system and from the EOG. It was found that the 1-camera system missed many blinks and that the blink duration was not in agreement with the blink duration obtained from the EOG and from the reference 3-camera system. However, the results also indicated that it should be possible to improve the blink detection algorithm since the raw data looked well in many cases where the algorithm failed to identify blinks.The sleepiness classifier was created using data from the simulator experiment. In the first step, the indicators identified in the literature review were implemented and evaluated. The indicators also included driving and context related parameters in addition to the blink related ones. The most promising indicators were then used as inputs to the classifier.
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| 6. |
- Piao, Shilong, et al.
(författare)
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Evaluation of terrestrial carbon cycle models for their response to climate variability and to CO2 trends
- 2013
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013. ; 19:7, s. 2117-2132
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate 10 process-based terrestrial biosphere models that were used for the IPCC fifth Assessment Report. The simulated gross primary productivity (GPP) is compared with flux-tower-based estimates by Jung etal. [Journal of Geophysical Research 116 (2011) G00J07] (JU11). The net primary productivity (NPP) apparent sensitivity to climate variability and atmospheric CO2 trends is diagnosed from each model output, using statistical functions. The temperature sensitivity is compared against ecosystem field warming experiments results. The CO2 sensitivity of NPP is compared to the results from four Free-Air CO2 Enrichment (FACE) experiments. The simulated global net biome productivity (NBP) is compared with the residual land sink (RLS) of the global carbon budget from Friedlingstein etal. [Nature Geoscience 3 (2010) 811] (FR10). We found that models produce a higher GPP (133 +/- 15Pg Cyr-1) than JU11 (118 +/- 6Pg Cyr-1). In response to rising atmospheric CO2 concentration, modeled NPP increases on average by 16% (5-20%) per 100ppm, a slightly larger apparent sensitivity of NPP to CO2 than that measured at the FACE experiment locations (13% per 100ppm). Global NBP differs markedly among individual models, although the mean value of 2.0 +/- 0.8Pg Cyr-1 is remarkably close to the mean value of RLS (2.1 +/- 1.2 Pg Cyr-1). The interannual variability in modeled NBP is significantly correlated with that of RLS for the period 1980-2009. Both model-to-model and interannual variation in model GPP is larger than that in model NBP due to the strong coupling causing a positive correlation between ecosystem respiration and GPP in the model. The average linear regression slope of global NBP vs. temperature across the 10 models is -3.0 +/- 1.5Pg Cyr-1 degrees C-1, within the uncertainty of what derived from RLS (-3.9 +/- 1.1Pg Cyr-1 degrees C-1). However, 9 of 10 models overestimate the regression slope of NBP vs. precipitation, compared with the slope of the observed RLS vs. precipitation. With most models lacking processes that control GPP and NBP in addition to CO2 and climate, the agreement between modeled and observation-based GPP and NBP can be fortuitous. Carbon-nitrogen interactions (only separable in one model) significantly influence the simulated response of carbon cycle to temperature and atmospheric CO2 concentration, suggesting that nutrients limitations should be included in the next generation of terrestrial biosphere models.
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| 7. |
- Schilke, Martin, 1980, et al.
(författare)
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Low cycle fatigue and deformation behaviour of austenitic manganese steel in rolled and as-cast conditions
- 2010
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Ingår i: Procedia Engineering: 10th International Fatigue Congress, FATIGUE 2010; Prague; Czech Republic; 6 June 2010 through 11 June 2010. - : Elsevier BV. - 1877-7058. ; 2:1, s. 623-628
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Konferensbidrag (refereegranskat)abstract
- This paper presents a characterisation of two austenitic manganese (~12-13 wt%) rail steels, one in rolled (Mn13(R)) and the other in as-cast (Mn13(C)) condition. Cyclic and monotonic behaviour as well as hardness and microstructure have been investigated. The results do not show any major difference between the materials, but comparison with literature reveals large differences compared to pearlitic and bainitic rail steels. The manganese steels are softer initially and harden during cyclic and monotonic loading.
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| 8. |
- van As, Dirk, et al.
(författare)
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Darkening of the Greenland ice sheet due to the melt-albedo feedback observed at PROMICE weather stations
- 2013
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Ingår i: Geological Survey of Denmark and Greenland Bulletin. - 1811-4598 .- 1604-8156. ; 28, s. 69-72
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Tidskriftsartikel (refereegranskat)abstract
- The Greenland ice sheet is losing mass (Barletta et al. 2012) and at least half of this loss is caused by an increase in surface melt (e.g. Tedesco et al. 2013). The other part is caused by increased dynamic mass loss, as marine-terminating glaciers lose resistive stresses (Nick et al. 2009) due to both retreat and meltwater lubrication at the bed (Sasgen et al. 2012).In 2007, the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) was initiated with the aim of gaining an insight into the causes of the ice-mass budget changes based on quantitative observations. This is primarily done by assessing how much mass is gained as snow accumulation on the surface versus how much is lost by calving and surface ablation (Ahlstrøm et al. 2008). PROMICE monitors the surface mass balance by means of automatic weather stations (AWSs) designed to quantify accumulation and ablation, as well as the specific energy sources contributing to ablation. These observations are vital to interpreting the physical mechanisms for ice-sheet response to climate change and for the calibration and validation of both satellite observations and climate models.In the wake of several record-breaking warm summers – increasing surface melt rate and extent (Nghiem et al. 2012) – interest in Greenland’s surface mass balance has increased (Tedesco et al. 2013). Observations of net ablation at PROMICE stations provided in situ confirmation of extreme massloss events in 2010 (Fausto et al. 2012) and 2012, primarily documented by other workers through satellite data. In this paper, we present atmospheric temperatures and surface solar reflectivity (known as albedo) of the Greenland ice sheet in the PROMICE period. Albedo modulates the absorption of solar radiation, which is the primary source of melt energy. It is reported to be decreasing in Greenland in recent years (Box et al. 2012), causing the monitoring of albedo variability to be increasingly important. Air temperatures, besides being strongly correlated to surface melt rates, affect surface albedo by controlling the rate of snow-grain metamorphism and the fraction of summer precipitation falling as rain versus snow. To elucidate the so-called melt-albedo feedback, whereby increased melt darkens the ice sheet and further enhances melt, the relationship between albedo and air temperature, observed at PROMICE stations, is examined in this study.
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| 9. |
- van As, Dirk, et al.
(författare)
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Katabatic winds and piteraq storms : observations from the Greenland ice sheet
- 2014
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Ingår i: Geological Survey of Denmark and Greenland Bulletin. - 1811-4598 .- 1604-8156. ; 31, s. 83-86
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Tidskriftsartikel (refereegranskat)abstract
- In 2007 the Programme for Monitoring the Greenland Ice Sheet (PROMICE) was initiated to observe and gain insight into the mass budget of Greenland ice masses. By means of in situ observations and remote sensing, PROMICE assesses how much mass is gained as snow accumulation on the surface versus how much is lost by iceberg calving and surface ablation (Ahlstrøm et al. 2008). A key element of PROMICE is a network of automatic weather stations (AWSs) designed to quantify components of the surface mass balance, including the energy exchanges contributing to surface ablation (Van As et al. 2013).The use of these AWS observations is not limited to studies of ice-sheet mass balance. PROMICE contributes to CryoNet (www.globalcryospherewatch.org/cryonet), the core network of surface measurement sites of the World Meteorological Organization (WMO) Global Cryosphere Watch. By real-time delivery through WMO, PROMICE observations contribute to improve both operational forecasting and climate analysis in the data-sparse Arctic. The Greenlandic population, highly dependent on accurate forecasting of weather conditions, benefits directly from these real-time observations. For instance, extreme surface wind speeds are a high-risk element in Greenland. The third-highest wind speed observed at the surface of the Earth (93 m/s or 333 km/h), was recorded in a 8–9 March 1972 storm at Thule in North-West Greenland (Stansfield 1972).In this paper, we discuss the extent to which the Greenland ice sheet generates its own near-surface wind field. We use PROMICE data to gain insight into the interaction between air temperature, radiation and gravity-driven katabatic winds. We focus on a particularly powerful spring storm in 2013 that contributed to a fatality on an ice-sheet ski traverse attempt (Linden 2013).
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