| 1. |
- Nakagawa, K., et al.
(författare)
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Modelling reactive solute transport from groundwater to soil surface under evaporation
- 2010
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 24:5, s. 608-617
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Tidskriftsartikel (refereegranskat)abstract
- Two-stage soil column experiments involving capillary rise and evaporation were conducted to improve understanding of salt and water movement from groundwater to soil surface. In total, 64 soil columns were placed in a tank partly filled with water in order to mimic the groundwater table in soil. Each soil column was analysed by dividing it into 27 segments to analyse pore water and ion distribution in both liquid and solid phases after prescribed time periods. The water and solute transport behaviour in the columns was simulated by a one-dimensional numerical model. The model considers the cation exchange of four cations (Ca2+, Mg2+, Na+ and K+) in both dissolved and exchangeable forms and anion retardation for one anion (SO42-). The Cl- is treated as a conservative solute without retardation. The numerical results of the cation distributions in both liquid and solid phases, anions in the liquid phase, and volumetric water contents were in relatively good agreement with the experimental results. To achieve a better model fit to these experimental results, a variable cation exchange capacity (CEC) distribution may be required. When a simple calculation scheme for evaporation intensity was applied, better predictions in terms of daily variation were achieved. The soil water profile displayed a steady state behaviour approximately 10 days after the start of the experiments. This was in agreement with numerical results and calculated distribution of velocity vectors. The final model includes cation exchange, anion retardation, and unsaturated water flow. Consequently, the model can be applied to study sequential irrigation effects on salt accumulation or reactive transport during major ion concentration changes in groundwater. Copyright (C) 2009 John Wiley & Sons, Ltd.
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| 2. |
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| 3. |
- Olsson, J., et al.
(författare)
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Neural Networks for rainfall forecasting by atmospheric downscaling
- 2004
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Ingår i: Journal of Hydrologic Engineering. - 1084-0699. ; 9:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have used artificial neural networks (NNs) to estimate local or regional recipitation/rainfall on the basis of relationships with coarse-resolution atmospheric variables. None of these experiments satisfactorily reproduced temporal intermittency and variability in rainfall. We attempt to improve performance by using two approaches: (1) couple two NNs in series, the first to determine rainfall occurrence, and the second to determine rainfall intensity during rainy periods; and (2) categorize rainfall into intensity categories and train the NN to reproduce these rather than the actual intensities. The experiments focused on estimating 12-h mean rainfall in the Chikugo River basin, Kyushu Island, southern Japan, from large-scale values of wind speeds at 850 hPa and precipitable water. The results indicated that (1) two NNs in series may greatly improve the reproduction of intermittency; (2) longer data series are required to reproduce variability; (3) intensity categorization may be useful for probabilistic forecasting; and (4) overall performance in this region is better during winter and spring than during summer and autumn.
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| 4. |
- Suzuki, Shintaro, et al.
(författare)
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An adult case of anaphylaxis caused by allergy to jellyfish
- 2017
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Ingår i: Arerugi Japanese Journal of Allergology. - 0021-4884. ; 66:6, s. 804-808
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Tidskriftsartikel (refereegranskat)abstract
- A 35-year-old female, professional diver, reported nausea, vomiting, and systemic hives 20 to 30 minutes after ingestion of antipasto made with jellyfish. Patient reported prior episodes of swelling after stings from several different creatures, including jelly fish. She also developed a systemic allergic reaction after sting from an unknown creature while diving. On the initial visit to our hospital, serum total IgE level was 545IU/mL We extracted crude allergen from jellyfish and evaluated allergen specific IgE antibody levels using ELISA. Patient samples showed higher levels of jellyfish-derived allergen specific IgE than healthy control samples. Basophils were isolated from the peripheral blood of patient. Stimulation with jellyfish-derived allergen showed expression of surface antigens on basophils increased in a concentration-dependent manner. Methods using sodium dodecyl sulfate poly acrylamide gel electrophoresis and immunoblotting showed acid-soluble collagen fraction from jellyfish contained above 250kDa weighed protein that may have caused this current event. A provocation test using jellyfish samples was not performed due to risk of anaphylactic shock. The patient was diagnosed with a jellyfish allergy due to IgE mediated anaphylaxis after ingestion. She was asked to refrain from consuming any food containing jellyfish. IgE-mediated food allergy caused by jellyfish is rare worldwide. Collagen was speculated to be an allergen in this study. Additional study to detect specific allergens related to jellyfish allergy would be particularly useful to specify disease phenotypes and individual care in future.
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| 5. |
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| 6. |
- Berndtsson, Ronny, et al.
(författare)
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Educating the compassionate water engineer - a remedy to avoid future water management failures?
- 2005
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 50:1, s. 7-16
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Tidskriftsartikel (refereegranskat)abstract
- The number of local and regional-scale water management failures appears steadily to increase despite an apparently higher level of engineering solutions at hand. The objective of this paper is to examine the challenges the existing education system needs to meet in order to produce water engineers capable of responding to the complexity of contemporary and future water problems in relation to societal needs. The next generation of water engineers may stay in their professional functions until 2040 or 2050. It is likely that in this period more critical water management and environmental problems will be experienced than have been encountered so far. The question then arises whether the present water engineers have the proper background education to understand environmental, hydrological, ecological and socio-economic problems to resolve related water management problems. Future water engineers must, to a greater extent, include socio-economic consequences in planned and/or designed water management systems and convey greater transparency regarding risks and societal effects.
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| 7. |
- Berndtsson, R., et al.
(författare)
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Solar-climatic relationship and implications for hydrology
- 2001
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Ingår i: Nordic Hydrology. - 0029-1277. ; 32:2, s. 65-84
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Tidskriftsartikel (refereegranskat)abstract
- Research during the latest years has indicated a significant connection between climate and solar activity. Specifically, a relationship between Northern Hemisphere air temperature and sunspot cycle length (SCL) has been shown. By using monthly SCL and land air temperature from 1753-1990 (238 years) we show that this relationship also holds for a single observation point in south of Sweden. Using data after 1850 yields a statistically significant linear correlation of 0.54 between SCL and mean temperature. Furthermore, we show that there are indications of a low-dimensional chaotic component in both SCL and the interconnected mean land air temperature. This has important implications for hydrology and water resources applications. By pure definition of chaos this means that it is virtually impossible to make long-term predictions of mean temperature. Similarly, because of the strong connection between temperature and many hydrological components, it is probable that also long-term water balance constituents may follow chaotic trajectories. Long-term projections of water resources availability may therefore be impossible. Repeated short-term predictions may, however, still be viable. We exemplify this by showing a technique to predict interpolated mean temperature 6 and 12 months ahead in real time with encouraging results. Improving the technique further may be possible by including information on the SCL attractor. To summarize, research into the possible existence of chaotic components in hydrological processes should be an important task for the next years to come.
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| 8. |
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| 9. |
- Hiroshiro, Y, et al.
(författare)
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Hydrogeochemical properties of a salinity-affected coastal aquifer in western Japan
- 2006
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 20:6, s. 1425-1435
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Tidskriftsartikel (refereegranskat)abstract
- Coastal groundwater aquifers are often exposed to heavy pumping and consequently to risks of saltwater intrusion. In many cases, however, the observed increase in groundwater salinity can only be partly explained by actual saltwater intrusion from the sea. Other salinity-increasing processes may also significantly contribute to the total salt content of the groundwater. This paper describes a geochemical investigation that was carried out to investigate recent salinity increases in groundwater for the Motooka coastal area in Fukuoka, Japan. A strong increase in electrical conductivity at 15-20 m depth was observed, corresponding to the freshwater and saltwater interface. Oxidation-reduction potentials observed in deeper groundwater were low, indicating long residence time for the groundwater. These results, together with hydrogen-oxygen isotope ratio analysis, indicated that the deeper groundwater is affected by seawater. Consequently, observed tritium concentration in the shallow groundwater system was higher than that of the deeper groundwater system, and a C-14 isotope dating of shell samples collected at 2 m depth indicated an age of about 2000 years. The overall results suggest that the aquifer was originally below the current sea floor and that deeper saline groundwater is not mixed with the shallower fresh groundwater. The deeper groundwater is, therefore, mainly affected by old seawater. In other words, modern saltwater intrusion has not yet occurred even if some wells contain saline water. The study shows that, even though coastal aquifers are heavily pumped, the reason for the rise in groundwater salinity may not necessarily be due to seawater intrusion. Further geochemical and hydrological investigations will be necessary to identify the underlying mechanisms. Copyright (c) 2006 John Wiley & Sons, Ltd.
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