| 1. |
- Duncanson, Laura, et al.
(författare)
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Aboveground biomass density models for NASA's Global Ecosystem Dynamics Investigation (GEDI) lidar mission
- 2022
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Ingår i: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 270
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Tidskriftsartikel (refereegranskat)abstract
- NASA's Global Ecosystem Dynamics Investigation (GEDI) is collecting spaceborne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDI's footprint-level (~25 m) AGBD (GEDI04_A) product, including a description of the datasets used and the procedure for final model selection. The data used to fit our models are from a compilation of globally distributed spatially and temporally coincident field and airborne lidar datasets, whereby we simulated GEDI-like waveforms from airborne lidar to build a calibration database. We used this database to expand the geographic extent of past waveform lidar studies, and divided the globe into four broad strata by Plant Functional Type (PFT) and six geographic regions. GEDI's waveform-to-biomass models take the form of parametric Ordinary Least Squares (OLS) models with simulated Relative Height (RH) metrics as predictor variables. From an exhaustive set of candidate models, we selected the best input predictor variables, and data transformations for each geographic stratum in the GEDI domain to produce a set of comprehensive predictive footprint-level models. We found that model selection frequently favored combinations of RH metrics at the 98th, 90th, 50th, and 10th height above ground-level percentiles (RH98, RH90, RH50, and RH10, respectively), but that inclusion of lower RH metrics (e.g. RH10) did not markedly improve model performance. Second, forced inclusion of RH98 in all models was important and did not degrade model performance, and the best performing models were parsimonious, typically having only 1-3 predictors. Third, stratification by geographic domain (PFT, geographic region) improved model performance in comparison to global models without stratification. Fourth, for the vast majority of strata, the best performing models were fit using square root transformation of field AGBD and/or height metrics. There was considerable variability in model performance across geographic strata, and areas with sparse training data and/or high AGBD values had the poorest performance. These models are used to produce global predictions of AGBD, but will be improved in the future as more and better training data become available.
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| 2. |
- Biber, Herbert, et al.
(författare)
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Solar wind Helium ion interaction with Mg and Fe rich pyroxene as Mercury surface analogue
- 2020
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : ELSEVIER. - 0168-583X .- 1872-9584. ; 480, s. 10-15
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Tidskriftsartikel (refereegranskat)abstract
- The surface of Mercury is continuously exposed to impinging solar wind ions. To improve the understanding of space weathering and exosphere formation, a detailed investigation of the ion-surface interaction is necessary. Magnesium and iron rich pyroxene (Ca,Mg,Fe)(2)[Si2O6] samples were used as analogues for Mercury's surface and irradiated with He+ ions at solar wind energies of 4 keV. Several regimes of implantation and sputtering were observed there. The total estimated mass of implanted He coincides with the mass decrease due to He outgassing during subsequent Thermal Desorption Spectroscopy measurements. Comparison to established modeling efforts and SDTrimSP simulations show that a He saturation concentration of 10 at.% has to be assumed. A complete removal of He is observed by heating to 530 K. On the surface of Mercury, temperatures between about 100 K and 700 K are expected. This temperature will therefore influence the implantation and release of He into Mercury's exosphere.
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| 3. |
- Block, Linda, et al.
(författare)
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Ultralow Dose of Naloxone as an Adjuvant to Intrathecal Morphine Infusion Improves Perceived Quality of Sleep but Fails to alter Persistent Pain: A Randomized, Double-blind, Controlled Study.
- 2015
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Ingår i: The Clinical journal of pain. - 1536-5409. ; 31:11, s. 968-975
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Tidskriftsartikel (refereegranskat)abstract
- This randomized, cross-over, double-blind, controlled study of continuous intrathecal morphine administration in patients with severe, long-term pain addresses whether the supplementation of low doses of naloxone in this setting is associated with beneficial clinical effects. All of the study subjects (n=11) provided informed consent and were recruited from a subset of patients who were already undergoing long-term treatment with continuous intrathecal morphine because of difficult-to-treat pain. The patients were (in a randomized order) also given intrathecal naloxone (40 ng/24 h or 400 ng/24 h). As control, the patients' ordinary dose of morphine without any additions was used. The pain (Numeric Rating Scale, NRS) during activity, perceived quality of sleep, level of activity and quality of life as well as the levels of several pro- and anti-inflammatory cytokines in the blood were assessed. The pre-study pain (NRS during activity) in the study group ranged from 3 to 10. 64% of the subjects reported improved quality of sleep during treatment with naloxone at a dose of 40 ng/24 hours compared with 9% with sham treatment (P=0.024). Although not statistically significant, pain was reduced by 2 NRS steps or more during supplemental treatment with naloxone in 36% of subjects when using the 40 ng/24 hours dose and in 18% of the subjects when using a naloxone 400 ng/24 hours dose. The corresponding percentage among patients receiving unaltered treatment was 27%. To conclude, the addition of an ultralow dose of intrathecal naloxone (40 ng/24 h) to intrathecal morphine infusion in patients with severe, persistent pain improves perceived quality of sleep. We were not able to show any statistically significant effects of naloxone on pain relief, level of activity or quality of life.This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivitives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/3.0.
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| 4. |
- Fleck, Sven, et al.
(författare)
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Omnidirectional 3D modeling on a mobile robot using graph cuts
- 2005
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Ingår i: Proceedings of the 2005 IEEE International Converence on Robotics and Automation. ; , s. 1748-1754
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Konferensbidrag (refereegranskat)abstract
- For a mobile robot it is a natural task to build a 3D model of its environment. Such a model is not only useful for planning robot actions but also to provide a remote human surveillant a realistic visualization of the robot’s state with respect to the environment. Acquiring 3D models of environments is also an important task on its own with many possible applications like creating virtual interactive walkthroughs or as basis for 3D-TV.In this paper we present our method to acquire a 3D model using a mobile robot that is equipped with a laser scanner and a panoramic camera. The method is based on calculating dense depth maps for panoramic images using pairs of panoramic images taken from different positions using stereo matching. Traditional 2D-SLAM using laser-scan-matching is used to determine the needed camera poses. To receive high-quality results we use a high-quality stereo matching algorithm – the graph cut method. We describe the necessary modifications to handle panoramic images and specialized post-processing methods.
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| 5. |
- Lindnér, Per, 1956, et al.
(författare)
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Hepatic artery occlusion and energy charge in rat liver tumour.
- 1994
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Ingår i: Annals of oncology : official journal of the European Society for Medical Oncology / ESMO. - 0923-7534. ; 5:10, s. 961-3
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Tidskriftsartikel (refereegranskat)abstract
- Hepatic artery ligation (HAL) is a model for inducing a vascular attack on liver tumours which causes a reduction in tumour growth. To determine in an experimental rat liver adenocarcinoma the duration and magnitude of changes in adenonucleotide concentration and energy charge (EC) after HAL, analyses of energy-rich nucleotides were performed at 1, 2, 24 and 168 hours after HAL or a SHAM procedure. There was a significant decrease of the ATP content and energy charge in the tumour one hour after HAL. Two hours after HAL this difference had decreased and with longer observation it was not detectable. Twenty-four hours of starvation did not significantly alter the effects of HAL on the tumour. HAL gives rise to a transient energy depletion of the tumour which is not completely compensated for by glycolysis after 1 hour, but is restored after 2 hours.
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| 6. |
- Lundborg, Christopher, 1965, et al.
(författare)
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High intrathecal bupivacaine for severe pain in the head and neck.
- 2009
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Ingår i: Acta Anaesthesiol Scand. - : Wiley. - 1399-6576. ; 53:7, s. 908-13
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Severe pain in the head and neck is associated with a lowered quality of life and conventional pain therapy often does not provide adequate relief. The aims of this study were to investigate the efficacy, pain relief, benefits and adverse effects of intracisternal or high cervical (IHC) administration of bupivacaine in patients with severe pain in the head, neck and face regions. METHODS: Between 1990 and 2005, 40 patients (age 27-84 years) were treated with continuous IHC infusions of bupivacaine for various non-cancer (n=15) or cancer-related (n=25) refractory pain conditions (duration 1 month-18 years) in the head, neck, mouth and shoulder regions. RESULTS: Visual analogue scale scores and opioid requirements decreased markedly after the start of the treatment and remained lowered throughout the study. No tachyphylaxis for bupivacaine was observed. Major side effects were few and most often transient. Most patients showed unchanged or improved mobility. There was no mortality, neurological damage or other severe events attributable to procedures in the study protocol. CONCLUSION: For patients with severe and refractory pain in areas innervated by cranial and upper cervical nerves, cervical high spinal analgesia can provide safe and effective analgesia.
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| 7. |
- Szabo, Paul S., et al.
(författare)
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Dynamic Potential Sputtering of Lunar Analog Material by Solar Wind Ions
- 2020
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Ingår i: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 891:1
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Tidskriftsartikel (refereegranskat)abstract
- Pyroxenes ((Ca, Mg, Fe, Mn)(2)Si2O6) belong to the most abundant rock forming minerals that make up the surface of rocky planets and moons. Therefore, sputtering of pyroxenes by solar wind ions has to be considered as a very important process for modifying the surface of planetary bodies. This is increased due to potential sputtering by multiply charged ions; to quantify this effect, sputtering of wollastonite (CaSiO3) by He2+ ions was investigated. Thin films of CaSiO3 deposited on a quartz crystal microbalance were irradiated, allowing precise, in situ, real time sputtering yield measurements. Experimental results were compared with SDTrimSP simulations, which were improved by adapting the used input parameters. On freshly prepared surfaces, He2+ ions show a significant increase in sputtering, as compared to equally fast He+ ions. However, the yield decreases exponentially with fluence, reaching a lower steady state after sputtering of the first few monolayers. Experiments using Ar8+ ions show a similar behavior, which is qualitatively explained by a preferential depletion of surface oxygen due to potential sputtering. A corresponding quantitative model is applied, and the observed potential sputtering behaviors of both He and Ar are reproduced very well. The results of these calculations support the assumption that mainly O atoms are affected by potential sputtering. Based on our findings, we discuss the importance of potential sputtering for the solar wind eroding the lunar surface. Estimated concentration changes and sputtering yields are both in line with previous modeling for other materials, allowing a consistent perspective on the effects of solar wind potential sputtering.
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