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| 2. |
- Dahlin, T., et al.
(författare)
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Geoelectrical resistivity monitoring for localizing gas at Landfills
- 2009
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Ingår i: Near Surface 2009 : 15th European Meeting of Environmental and Engineering Geophysics - 15th European Meeting of Environmental and Engineering Geophysics. - 9073781728 - 9789073781726
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Konferensbidrag (refereegranskat)abstract
- In order to assess the potential of electrical resistivity for imaging gas migration at landfills, two relatively well-known sites - one bioreactor landfill and a conventional landfill - have been monitored successively. A three-dimensional resistivity image could be constructed every two hour on both sites. Meteorological parameters were monitored at the same time, with one measurement taken every hour. Methane concentration was measured in the air at several occasions, the pore pressure was monitored at two locations and some relative estimations of moisture in the top layer were made at the second site. The results show imperfect but interesting correlations between the different parameters and give a hint of how the method could be refined. The resistivity depends on several parameters, but the areas where the resistivity is most variable seem to be clearly related to higher gas emissions.
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| 3. |
- Rosqvist, K., et al.
(författare)
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Factors associated with life satisfaction in Parkinson's disease
- 2017
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 136:1, s. 64-71
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To identify factors associated with life satisfaction (LS) in people with Parkinson's disease (PD), including a specific focus on those with late-stage PD. Material and methods: The study included 251 persons with PD (median age 70 years; PD duration 8 years). Analyses involved the total sample and a subsample with late-stage PD, that is Hoehn and Yahr stages IV and V (n=62). LS was assessed with item 1 of the Life Satisfaction Questionnaire (LiSat-11). Simple logistic regression analyses were performed for both the total sample and for the subsample with late-stage PD. For the total sample, a multivariable logistic regression analysis was also performed. Results: In the total sample, 12 of the 20 independent variables were significantly associated with LS: need of help with ADL; walking difficulties; number of non-motor symptoms (NMS); fatigue; depressive symptoms; general self-efficacy; motor symptoms; pain; PD severity; freezing episodes; gender (woman); and fluctuations. When controlling for age and gender in the multivariable logistic regression model, depressive symptoms were negatively associated with high LS and general self-efficacy was positively associated with high LS. In late-stage PD, simple logistic regression analyses (controlling for age and gender) identified the following factors as associated with LS: number of NMS, general self-efficacy, walking difficulties and fatigue. Conclusions: This study provides new knowledge on factors associated with LS in a PD sample, including those with late-stage PD. As the ultimate goal for PD care should be improvement in LS, the results have direct clinical implication.
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| 4. |
- Staubo, Sara C., et al.
(författare)
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Dopamine agonist serum concentrations and impulse control disorders in Parkinson's disease
- 2023
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Ingår i: European Journal of Neurology. - 1351-5101.
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Impulse control disorders (ICDs) are common among Parkinson's disease patients using dopamine agonists. We wanted to determine whether ICD patients have higher dopamine agonist serum concentrations than those without any sign of ICD. Methods: Patients who used either pramipexole or ropinirole depot once daily were screened for ICDs using the validated Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease–Rating Scale. Those who scored above the cut-off for one or more of the four defined ICDs (gambling, compulsive sexual behavior, compulsive shopping, and binge-eating) were compared in a case–control study to patients who scored zero points (no evidence of ICD) on the same items. They were examined clinically and evaluated using relevant scales. Three blood samples were taken on the same day: before daily dose, and then 6 and 12 h later. Results: Forty-six patients were included: 19 ICD-positive and 27 controls. Ropinirole serum concentrations 6 h after daily intake (Cmax) were higher in the case group compared to the control group, as was the daily ropinirole dosage. No differences were observed in serum concentrations, dosage or total drug exposure for pramipexole. Disease duration and length of dopamine agonist treatment was significantly longer among ICD patients for ropinirole, but not for pramipexole. Conclusions: The use of pramipexole may in itself confer high ICD risk, whereas ICDs among ropinirole users depend more on serum concentration and drug exposure. The pharmacokinetic properties of ropinirole make it challenging to predict its effects on patients, which supports the need for therapeutic drug monitoring to reduce risk of ICD.
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| 5. |
- Bendz, D., et al.
(författare)
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Kinematic wave model for water movement in municipal solid waste
- 1998
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Ingår i: Water Resources Research. - 0043-1397. ; 34:11, s. 2963-2970
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Tidskriftsartikel (refereegranskat)abstract
- The movement of water in a large (3.5 m(3)) undisturbed sample of 22-year-old municipal solid waste has been modeled using a kinematic wave approximation for unsaturated infiltration and internal drainage. The model employs a two-parameter power expression as macroscopic flux law. The model parameters were determined and interpreted in terms of the internal geometry of the waste medium by fitting the model to one set of infiltration and drainage data. The model was validated using another set of data from a sequence of water input events. The results of the validation show that the model performs satisfactorily, but further development of the model to incorporate spatial variability would increase its capability.
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| 6. |
- Bokhorst, Stef, et al.
(författare)
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Changing Arctic snow cover : A review of recent developments and assessment of future needs for observations, modelling, and impacts
- 2016
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 45:5, s. 516-537
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Forskningsöversikt (refereegranskat)abstract
- Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for impact assessments and adaptation strategies. Although much progress has been made in understanding and predicting snow-cover changes and their multiple consequences, many uncertainties remain. In this paper, we review advances in snow monitoring and modelling, and the impact of snow changes on ecosystems and society in Arctic regions. Interdisciplinary activities are required to resolve the current limitations on measuring and modelling snow characteristics through the cold season and at different spatial scales to assure human well-being, economic stability, and improve the ability to predict manage and adapt to natural hazards in the Arctic region.
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| 7. |
- Dahlin, T., et al.
(författare)
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Resistivity-ip characterisation and short term monitoring at filborna waste deposit
- 2012
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Ingår i: 74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012 : Responsibly Securing Natural Resources - Responsibly Securing Natural Resources. - 9781629937908 ; , s. 4667-4671
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Konferensbidrag (refereegranskat)abstract
- Buried waste in old landfills is an increasing problem as cities expand and grow into areas with former waste deposits. In order to be able to manage and as far as possible reclaim land in such areas, better tools are needed for mapping and characterisation of buried waste and contaminated land. Other problems associated with landfills are leachate water and methane emissions. In the results presented internal landfill structure was successfully mapped using a combination of resistivity and time-domain IP. Differences in electrical properties can be related to different types of materials, and the groundwater level is outlined. Furthermore the results indicate that leachate water migrates into a former stream under the landfill. Variations in resistivity linked to variation in fluid and gas content were captured by short term monitoring. A rainfall event that occurred during the monitoring period acts as an infiltration test and the changes in resistivity outlines the water migration pattern. The results show the potential of resistivity monitoring for tracing fluid migration in the ground, and also shows patterns that may be due to increasing gas contents in line with previous studies.
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| 8. |
- Jonsson, C. E., et al.
(författare)
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High-resolution diatom d18O records from two sub-Arctic high-altitude lakes in the Swedish Scandes
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Ingår i: Journal of Quaternary Science. - 0267-8179 .- 1099-1417.
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Tidskriftsartikel (refereegranskat)abstract
- Waters from high altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature, and relatively short hydraulic residence times, most high altitude lakes have lake water isotopic compositions (δ18Olake) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water d18O. Here we compare two high resolution δ18Odiatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900 to AD 1990 is characterized by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ18Odiatom as decreasing trends. Lowest δ18Odiatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 years the main factor affecting the δ18Odiatom signal in these sub-Arctic high altitude lakes with short residence times has been changes in amount of winter precipitation and that δ18Odiatom derived from high altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy.
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| 9. |
- Jonsson, C. E., et al.
(författare)
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Two diatom oxygen isotope records from Naimakka in northern Fennoscandia: implications for Holocene palaeohydrology and atmospheric circulation dynamics
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This study present past changes in lake water oxygen isotope composition (δ18Olakew) calculated from diatom oxygen isotope composition (δ18Odiatom) from two lake sediment records. The two sediment sequences (9500 and 2800 years) are from open-basin lakes, although with different hydrologies, and are located close to a meteorological station in Naimakka, Northern Fennoscandia. The isotope composition of lake waters was analysed to determine the modern regional hydrological setting. Our results show that changes in the isotope composition of precipitation (δ18Op) is the primary forcing mechanism decreasing or increasing the δ18Olakew values in both lakes. Changes in the isotope signals are interpreted as reflecting regional variations in atmospheric circulation and climatic seasonality. δ18Odiatom from Lake Keitjoru, covering the last 9500 years, shows a depletion trend of 1.3‰ from c. 8000 until around 1500 cal yr BP. This decrease is thought to be due to a long term decrease in the influence of a zonal airflow (strong westerlies, relatively high δ18Op) over Fennoscandia in favor of an increasing proportion of colder meridional airflow (weak westerlies, lower δ18Op) from the north. A synchronous shift to lower δ18O values was recorded in Lake Keitjoru and lake Oikojärvi around 700-600 cal yr BP (~AD 1250-1350), a time when European climate deteriorated into the “Little Ice Age”. We argue that a circulation pattern dominated by meridional airflow, with reduced westerlies over Northern Fennoscandia and high amounts of winter precipitation from southeast or north, replaced a zonal atmospheric circulation pattern at this time. The δ18Odiatom minima c. 400 and 50 cal yr BP (~AD 1550 and AD 1900) is likely also a response to shifts in circulation, which is also seen in lower summer temperatures at that time recorded in tree-rings and from pollen data. The fact that the same isotope shifts have been detected in δ18O records from hydrological different lakes lends support to our conclusion that these records reflect variations in atmospheric circulation pattern.
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| 10. |
- Lumetzberger, M., et al.
(författare)
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Predicting the fate of chlorinated aliphatics by hydrogeological modelling and DCIP data - Färgaren case study
- 2019
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Konferensbidrag (refereegranskat)abstract
- We present a local flow model approach for the transport and the decay of a roughly 50 year old perchloroethylene contamination at a former dry cleaning facility at Kv. Färgaren in Kristianstad that sits above the largest aquifer in Sweden. The study demonstrates an efficient workflow integrating ERT for conceptualising and calibrating a three dimensional transient, multi aquifer groundwater transport problem with a sequential first-order decay contamination where only limited sample data is available for calibration - i.e. non-ideal, real world conditions. The 3D hydraulic model geometry is based on information from ERT data. It was possible to map resistivity signatures correlated with boreholes to geological features with a high degree of accuracy. On the Färgaren site itself, a 3D IP inversion model displayed some IP effects that correlated with historical perchloroethylene source terms. The simulations provide new information regarding the vulnerability of a critical groundwater resource, filling in knowledge gaps left by traditional sampling methods. It is concluded that there is potential for long term contamination of the regional sandstone aquifer, and that the plume front may already have reached its upper layers.
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