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Sökning: WFRF:(Prieto Carmen)

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1.
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2.
  • 2019
  • Tidskriftsartikel (refereegranskat)
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3.
  • Ballesteros, Soledad, et al. (författare)
  • A randomized controlled trial of brain training with non-action video games in older adults : results of the 3-month follow-up
  • 2015
  • Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • This randomized controlled study (ClinicalTrials.gov NCT02007616)investigated the maintenance of training effects of 20 1-hr non-action video gametraining sessions with selected games from a commercial package on several agedecliningcognitive functions and subjective wellbeing after a 3-month no-contactperiod. Two groups of cognitively normal older adults participated in both the posttraining(posttest) and the present follow-up study, the experimental group who receivedtraining and the control group who attended several meetings with the research teamduring the study but did not receive training. Groups were similar at baseline ondemographics, vocabulary, global cognition, and depression status. Significant improvements in the trained group, and no variation in the control group had been previously found at posttest, in processing speed, attention and visual recognition memory, as well as in two dimensions of subjective wellbeing. In the current study, improvement from baseline to 3 months follow-up was found only in wellbeing (Affection and Assertivity dimensions) in the trained group whereas there was no change in the control group. Previous significant improvements in processing speed, attentionand spatial memory become nonsignificant after the 3-month interval. Training olderadults with non-action video games enhanced aspects of cognition just after training butthis effect disappeared after a 3-month no-contact follow-up period. Cognitive plasticitycan be induced in older adults by training, but to maintain the benefits periodic boosting sessions would be necessary.
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4.
  • Ballesteros, Soledad, et al. (författare)
  • Brain training with non-action video games enhances aspects of cognition in older adults : a randomized controlled trial
  • 2014
  • Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media S.A.. - 1663-4365. ; 6
  • Tidskriftsartikel (refereegranskat)abstract
    • Age-related cognitive and brain declines can result in functional deterioration in many cognitive domains, dependency, and dementia. A major goal of aging research is to investigate methods that help to maintain brain health, cognition, independent living and wellbeing in older adults. This randomized controlled study investigated the effects of 20 1-hr non-action video game training sessions with games selected from a commercially available package (Lumosity) on a series of age-declined cognitive functions and subjective wellbeing. Two groups of healthy older adults participated in the study, the experimental group who received the training and the control group who attended two meetings with the research team along the study. Groups were similar at baseline on demographics, vocabulary, global cognition, and depression status. All participants were assessed individually before and after the intervention, or a similar period of time, using neuropsychological tests and laboratory tasks to investigate possible transfer effects. The results showed significant improvements in the trained group, and no variation in the control group, in processing speed (choice reaction time), attention (reduction of distraction and increase of alertness), immediate and delayed visual recognition memory, as well as a trend to improve in Affection and Assertivity, two dimensions of the Wellbeing Scale. Visuospatial working memory (WM) and executive control (shifting strategy) did not improve. Overall, the current results support the idea that training healthy older adults with non-action video games will enhance some cognitive abilities but not others.
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5.
  • Bring, Arvid, et al. (författare)
  • Contrasting Hydroclimatic Model-Data Agreements Over the Nordic-Arctic Region
  • 2019
  • Ingår i: Earth's Future. - : John Wiley and Sons Inc. - 2328-4277. ; 7:12, s. 1270-1282
  • Tidskriftsartikel (refereegranskat)abstract
    • Rapid changes in high-latitude hydroclimate have important implications for human societies and environment. Previous studies of different regions have indicated better agreement between climate model results and observation data for the thermodynamic variable of surface air temperature (T) than for the water variables of precipitation (P), evapotranspiration (ET), and runoff (R). Here we compare climate model output with observations for 64 Nordic and Arctic hydrological basins of different sizes, and for the whole region combined. We find an unexpectedly high agreement between models and observations for R, about as high as the model-observation agreement for T and distinctly higher than that for P or ET. Model-observation agreement for R and T is also consistently higher on the whole-region scale than individual basin scales. In contrast, model-observation agreement for P and ET is overall lower, and for some error measures also lower for the whole region than for individual basins of various scales. Region-specific soil freeze-thaw bias of climate models can at least partly explain the low model-observation agreement for P and ET, while leaving modeled R relatively unaffected. Thereby, model projections for this region may be similarly reliable and directly useful for large-scale average conditions of R as of T.
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6.
  • Bring, Arvid, et al. (författare)
  • Implications of freshwater flux data from the CMIP5 multimodel output across a set of Northern Hemisphere drainage basins
  • 2015
  • Ingår i: EARTHS FUTURE. - 2328-4277. ; 3:6, s. 206-217
  • Tidskriftsartikel (refereegranskat)abstract
    • The multimodel ensemble of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) synthesizes the latest research in global climate modeling. The freshwater system on land, particularly runoff, has so far been of relatively low priority in global climate models, despite the societal and ecosystem importance of freshwater changes, and the science and policy needs for such model output on drainage basin scales. Here we investigate the implications of CMIP5 multimodel ensemble output data for the freshwater system across a set of drainage basins in the Northern Hemisphere. Results of individual models vary widely, with even ensemble mean results differing greatly from observations and implying unrealistic long-term systematic changes in water storage and level within entire basins. The CMIP5 projections of basin-scale freshwater fluxes differ considerably more from observations and among models for the warm temperate study basins than for the Arctic and cold temperate study basins. In general, the results call for concerted research efforts and model developments for improving the understanding and modeling of the freshwater system and its change drivers. Specifically, more attention to basin-scale water flux analyses should be a priority for climate model development, and an important focus for relevant model-based advice for adaptation to climate change.
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8.
  • Chen, Yuanying (författare)
  • Land-Sea Interactions in the Coastal-Marine System of the Baltic Sea under Hydro-Climatic Variability
  • 2020
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis investigates a few important component processes for understanding and quantifying eutrophication in the Baltic Sea, that include characterization of nutrient loadings from land, water flow in the sea under changing climate conditions and transport of solutes originating from different locations along the coast. Furthermore, this study aims to improve our understanding on how processes from land (the nutrient loading conditions) and the sea (transport dynamics and water quality) couple to determine the fate of nutrients in the sea and the water quality in a selected localized coastal area, the Himmerfjärden Bay.Comprehensive data are compiled as a basis for numerical simulations. An open source tool for oceanographic studies FVCOM is used to simulate flow and transport processes in the Baltic Sea. Hydrodynamic simulations are verified in terms of temperature, salinity and water level for the year 2005. Results show that most of the investigated Swedish watersheds along the coastline are dominated by subsurface legacy sources, the loads of which are positively and linearly correlated with river discharges. Moreover, subsurface legacy sources are less likely to decrease over time compared with the current surface sources. The Baltic Sea has a stable flow structure considering flux directions between basins, while the flux magnitudes between basins are mainly determined by different wind conditions. The spreading patterns in the sea with solute released from different coastal areas are similar when the released amounts are comparable, even though different cases have different source input and water flow conditions. The overall spreading patterns in the sea are generally dominated by the total mass of released solute. Local transport dynamics and patterns around the coast differ greatly for different cases and are determined by the local flow conditions. Different water quality indicators are influenced by different land-based or sea-based measures for water quality improvement. The dry-cold hydro-climatic condition is the most favorable for improving the water quality and elevating the ecological status in the Himmerfjärden Bay.Based on this investigation, varying hydro-climatic factors impose important influence on the different component processes of nutrient loading from land to the sea. For example, the change of river discharges from land in the future would influence the total load into the sea from subsurface legacy sources, and finally influence the general spreading patterns of nutrients in the sea. The change of wind conditions would affect the flow and transport dynamics at local scale and flow fluxes magnitudes between marine basins at the sea scale. Change towards a dry-cold condition would be beneficial for the water quality and lead to improvement of coastal water quality, while the change towards a wet-warm condition will be generally unfavorable for improving the water quality. Clearly more comprehensive studies are needed based on the component processes considered in this thesis, for mapping water quality and eutrophication long-term trends in the Baltic Sea with confidence that is sufficient for effective mitigation measures and policies. 
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9.
  • Chen, Yuanying, et al. (författare)
  • Nutrient source attribution : Quantitative typology distinction of active and legacy source contributions to waterborne loads
  • 2021
  • Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35:7
  • Tidskriftsartikel (refereegranskat)abstract
    • Distinction between active and legacy sources of nutrients is needed for effective reduction of waterborne nutrient loads and associated eutrophication. This study quantifies main typological differences in nutrient load behaviour versus water discharge for active and legacy sources. This quantitative typology is used for source attribution based on monitoring data for water discharge and concentrations of total nitrogen (TN) and total phosphorous (TP) from 37 catchments draining into the Baltic Sea along the coastline of Sweden over the period 2003-2013. Results indicate dominant legacy source contributions to the monitored loads of TN and TP in most (33 of the total 37) study catchments. Dominant active sources are indicated in 1 catchment for TN, and mixed sources are indicated in 3 catchments for TN, and 4 catchments for TP. The TN and TP concentration contributions are quantified to be overall higher from the legacy than the active sources. Legacy concentrations also correlate well with key indicators of human activity in the catchments, agricultural land share for TN (R-2 = 0.65) and population density for TP (R-2 = 0.56). Legacy-dominated nutrient concentrations also change more slowly than in catchments with dominant active or mixed sources. Various data-based results and indications converge in indicating legacy source contributions as largely dominant, mainly anthropogenic, and with near-zero average change trends in the present study of catchments draining into the Baltic Sea along the coastline of Sweden, as in other parts of the world. These convergent indications emphasize needs to identify and map the different types of sources in each catchment, and differentiate strategies and measures to target each source type for possible achievement of shorter- and longer-term goals of water quality improvement.
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10.
  • Coronado, Liani, et al. (författare)
  • Positive selection pressure on E2 protein of classical swine fever virus drives variations in virulence, pathogenesis and antigenicity : implication for epidemiological surveillance in endemic areas
  • 2019
  • Ingår i: Transboundary and Emerging Diseases. - : Blackwell Verlag. - 1865-1674 .- 1865-1682. ; 66:6, s. 2362-2382
  • Tidskriftsartikel (refereegranskat)abstract
    • Classical swine fever (CSF), caused by CSF virus (CSFV), is considered one of the most important infectious diseases with devasting consequences for the pig industry. Recent reports describe the emergence of new CSFV-strains resulting from the action of positive selection pressure, due mainly to the bottleneck effect generated by ineffective vaccination. Even though a decrease in the genetic diversity of the positive selected CSFV-strains has been observed by several research groups, there is little information about the effect of this selective force on the virulence degree, antigenicity and pathogenicity of this type of strains. Hence, the aim of the current study was to determine the effect of the positive selection pressure on these three parameters of CSFV-strains, emerged as result of the bottleneck effects induced by unproper vaccination in a CSF-endemic area. Moreover, the effect of the positive selected strains on the epidemiological surveillance system was assessed. By the combination of in vitro, in vivo and immunoinformatic approaches we revealed that the action of the positive selection pressure induces a decrease in virulence and alteration in pathogenicity and antigenicity. However, we also noted that the evolutionary process of CSFV, especially in segregated microenvironments, could contribute to the gain-fitness event, restoring the highly virulent pattern of the circulating strains. Besides, we denoted that the presence of low virulent strains selected by bottleneck effect after inefficient vaccination can lead to a relevant challenge for the epidemiological surveillance of CSF, contributing to under-reports of the disease, favoring the perpetuation of the virus in the field. In this study B-cell and CTL epitopes on the E2 3D-structure model were also identified. Thus, the current study provides novel and significant insights into variation in virulence, pathogenesis and antigenicity experienced by CSFV strains after the positive selection pressure effect.
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11.
  • Darracq, Amelie, et al. (författare)
  • Quantification of advective solute travel times and mass transport through hydrological catchments
  • 2010
  • Ingår i: Environmental Fluid Mechanics. - : Springer Science and Business Media LLC. - 1567-7419 .- 1573-1510. ; 10:1-2, s. 103-120
  • Tidskriftsartikel (refereegranskat)abstract
    • This study has investigated and outlined the possible quantification and mapping of the distributions of advective solute travel times through hydrological catchments. These distributions are essential for understanding how local water flow and solute transport and attenuation processes affect the catchment-scale transport of solute, for instance with regard to biogeochemical cycling, contamination persistence and water quality. The spatial and statistical distributions of advective travel times have been quantified based on reported hydrological flow and mass-transport modeling results for two coastal Swedish catchments. The results show that the combined travel time distributions for the groundwater-stream network continuum in these catchments depend largely on the groundwater system and model representation, in particular regarding the spatial variability of groundwater hydraulic parameters (conductivity, porosity and gradient), and the possible contributions of slower/deeper groundwater flow components. Model assumptions about the spatial variability of groundwater hydraulic properties can thus greatly affect model results of catchment-scale solute spreading. The importance of advective travel time variability for the total mass delivery of naturally attenuated solute (tracer, nutrient, pollutant) from a catchment to its downstream water recipient depends on the product of catchment-average physical travel time and attenuation rate.
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12.
  • Darracq, Amelie, et al. (författare)
  • Scale and model resolution effects on the distributions of advective solute travel times in catchments
  • 2010
  • Ingår i: Hydrological Processes. - : John Wiley & Sons, Ltd.. - 0885-6087 .- 1099-1085. ; 24:12, s. 1697-1710
  • Tidskriftsartikel (refereegranskat)abstract
    • Advective solute travel times and their distributions in hydrological catchments are useful descriptors of the dynamics and variation of the physical mass transport among and along the different source-to-recipient pathways of solute transport through the catchments. This article investigates the scale dependence and the effects of model and data resolution on the quantification of advective travel times and their distributions in the Swedish catchment areas of Norrström and Forsmark. In the surface water networks of the investigated (sub)catchments, the mean advective travel time increases with (sub)catchment scale, whereas the relative travel time variability around the mean value (coefficient of variation, CV) is scale-invariant and insensitive to model resolution. In the groundwater and for the whole (sub)catchments, both the mean value and the CV of travel times are scale-invariant, but sensitive to model resolution and accuracy. Such quantifications and results of advective travel times constitute important steps in the development of improved understanding and modelling of nutrient, pollutant and tracer transport through catchments.
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13.
  • Destouni, Georgia, et al. (författare)
  • Biogeochemical Transformation Pathways through the Land-water Geosphere
  • 2014
  • Konferensbidrag (refereegranskat)abstract
    • Water on land undergoes and participates in many biogeochemical exchanges and changes. A bits-and-pieces approach to these may miss essential aspects of change propagation and transformation by land-water through different segments of the Earth system. This paper proposes a conceptualization of the entire land-water geosphere as a scale-free catchment-wise organised system (Figure 1), emphasizing four key new system aspects compared to traditional hydrosphere/water cycle view: i) distinction of coastal divergent in addition to traditional convergent catchments; ii) physical and social-ecological system coupling through four main nodal zones/interfaces (surface, subsurface, coastal, observation); iii) flow-transport pathways as system coupling agents; iv) multiple interactions with the anthroposphere as integral system parts. Utilizing this conceptualization, we identify distinct patterns of direct anthropogenic change in large-scale water and waterborne nutrient fluxes, emerging across different parts of the world. In general, its embedment directly in the anthroposphere/technosphere makes land-water a key geosphere for understanding and monitoring human-driven biogeochemical changes. Further progress in system-level understanding of such changes requires studies of land-water as a continuous yet structured geosphere following the proposed spatiotemporal pathways of change propagation-transformation.
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15.
  • Destouni, Georgia, et al. (författare)
  • Hydro-Biogeochemical and Environmental-Management Functions of Wetland Networks in Landscapes
  • 2012
  • Ingår i: 9th INTECOL International Wetlands Conference, Wetlands in a Complex World. ; , s. 915-
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • A main application goal of ecohydrological science is to amplify opportunities of achieving water quality improvements, biodiversity enhancements and sustainable development, by improved understanding and use of ecosystem properties as a management tool. This paper draws on and synthesizes main result implications for the function and possible enhanced use of wetland networks in the landscape as such a tool, from a series of hydro-biogeochemical and environmental economics studies of nutrient/pollutant loading and abatement in different Swedish hydrological catchments. Results show large potential of wetland networks to reduce the cost of abating nutrient and metal loads within and from hydrological catchments, and emphasize some main research questions for further investigations of actual possibilities to realize this potential. The questions regard in particular the ability of wetland networks to extend the travel times and reduce the uncertainty of hydrological nutrient/pollutant transport through catchments.The paper further presents and discusses some main joint conclusions of the participants in a recently held International Workshop on Ecohydrology and Integrated Water Resource Management (1) at the Navarino Environmental Observatory in Messinia, Greece (2), regarding essential goals for collaborative international efforts in wetland network research. The goals include to investigate on different spatiotemporal scales and in different world regions: a) the dynamics of natural and managed wetland networks across a gradient of different climate, human disturbance, energy and organization conditions; b) the reciprocal interactions between wetland networks and associated hydrological catchments; c) how climate change and different human activities in the wetland network catchments influence these interactions (in b) and generally the ecohydrology of individual wetlands and the whole wetland networks; and d) the ecosystem services provided by networks of wetlands.
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16.
  • Destouni, Georgia, et al. (författare)
  • Hydroclimatic shifts driven by human water use for food and energy production
  • 2013
  • Ingår i: Nature Climate Change. - 1758-678X .- 1758-6798. ; 3:3, s. 213-217
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrological change is a central part of global change(1-3). Its drivers in the past need to be understood and quantified for accurate projection of disruptive future changes(4). Here we analyse past hydro-climatic, agricultural and hydropower changes from twentieth century data for nine major Swedish drainage basins, and synthesize and compare these results with other regional(5-7) and global(2) assessments of hydrological change by irrigation and deforestation. Cross-regional comparison shows similar increases of evapotranspiration by non-irrigated agriculture and hydropower as for irrigated agriculture. In the Swedish basins, non-irrigated agriculture has also increased, whereas hydropower has decreased temporal runoff variability. A global indication of the regional results is a net total increase of evapotranspiration that is larger than a proposed associated planetary boundary(8). This emphasizes the need for climate and Earth system models to account for different human uses of water as anthropogenic drivers of hydro-climatic change. The present study shows how these drivers and their effects can be distinguished and quantified for hydrological basins on different scales and in different world regions. This should encourage further exploration of greater basin variety for better understanding of anthropogenic hydro-climatic change.
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17.
  • Destouni, Georgia, 1961-, et al. (författare)
  • Needs and means to advance science, policy and management understanding of the freshwater system : A synthesis report
  • 2015
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Fragmented and inconsistent understanding of the freshwater system limits our ability to achieve water security and sustainability under the human-driven changes occurring in the Anthropocene. To advance system-level understanding of freshwater, gaps and inconsistencies in knowledge, data, representations and links of processes and subsystems need to be identified and bridged under consideration of the freshwater system as a continuous whole. Based on such identification, a freshwater system conceptualization is developed in this report, which emphasizes four essential, yet often neglected system aspects:i) Distinction of coastal divergent catchments.ii) Four main zones (surface, subsurface, coastal, observation) of different types of freshwater change.iii) Water pathways as system-coupling agents that link and partition water change among the four change zones.iv) Direct interactions with the anthroposphere as integral system pathways across the change zones.We explain and exemplify some key implications of these aspects, identifying in the process also distinct patterns of human-driven changes in large-scale water fluxes and nutrient loads.The present conceptualization provides a basis for common inter- and trans-disciplinary understanding and systematic characterization of the freshwater system function and its changes, and of approaches to their modeling and monitoring. This can be viewed and used as a unifying checklist that can advance science, policy and management of freshwater and related environmental changes across various scales and world regions.
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18.
  • Destouni, Georgia, et al. (författare)
  • On the possibility for generic modeling of submarine groundwater discharge
  • 2003
  • Ingår i: Biogeochemistry. - 0168-2563 .- 1573-515X. ; 66:1-2, s. 171-186
  • Tidskriftsartikel (refereegranskat)abstract
    • We simulate large-scale dynamics of submarine groundwater discharge (SGD) in three different coastal aquifers on the Mediterranean Sea. We subject these aquifers to a wide range of different groundwater management conditions, leading to widely different net groundwater drainage from land to sea. The resulting SGD at steady-state is quantifiable and predictable by simple linearity in the net land-determined groundwater drainage, defined as total fresh water drainage minus groundwater extraction in the coastal aquifer system. This linearity appears to be general and independent of site-specific, variable and complex details of hydrogeology, aquifer hydraulics, streamlines and salinity transition zones in different coastal systems. Also independently of site-specifics, low SGD implies high seawater content due to seawater intruding into the aquifer and mixing with fresh groundwater within a wide salinity transition zone in the aquifer. Increasing SGD implies decreasing seawater content, decreased mixing between seawater and fresh groundwater and narrowing of the salinity transition zone of brackish groundwater in the aquifer.
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19.
  • Destouni, Georgia, et al. (författare)
  • Quantifying hydrological and tidal influences on groundwater discharges into coastal waters
  • 2005
  • Ingår i: Water resources research. - 0043-1397 .- 1944-7973. ; 41:12, s. W12427-
  • Tidskriftsartikel (refereegranskat)abstract
    • [1] In coastal aquifers the dynamic mixing zone between intruding seawater and fresh groundwater constitutes a zone of salinity transition that may supply brackish groundwater along with chemical tracers and nutrients to coastal waters. Tidal influence has been proposed as a possible mechanism for enhancement of recirculated seawater, total submarine groundwater discharge (SGD), and associated tracer loading through salinity transition zones into coastal waters. We show that tidal oscillation may, for relatively low SGD cases, considerably increase the average recirculated seawater component of total SGD relative to nontidal conditions. High SGD cases, however, are dominated by and require large fresh groundwater flow components also under tidal conditions; this result is obtained from a wide range of different groundwater simulation scenarios and is supported by direct comparison with field data from different reported high-SGD sites in the world. For cases with hydrologically limited fresh groundwater flow directly into the sea we propose that observed excessive coastal loading of groundwater-derived tracers may be the result of large groundwater flow and transport into unmonitored coastal stream reaches, in addition to SGD.
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21.
  • Destouni, Georgia, et al. (författare)
  • Robust Assessment of Uncertain Freshwater Changes : The Case of Greece with Large Irrigation-and Climate-Driven Runoff Decrease
  • 2018
  • Ingår i: Water. - : MDPI AG. - 2073-4441. ; 10:11
  • Tidskriftsartikel (refereegranskat)abstract
    • We develop a data-driven approach to robustly assess freshwater changes due to climate change and/or human irrigation developments by use of the overarching constraints of catchment water balance. This is applied to and tested in the high-uncertainty case of Greece for five nested catchments of different scales across the country and for freshwater changes from an early period (1930-1949) with small human influences on climate and irrigation to a recent period (1990-2009) with expected greater such influences. The results show more or less equal contributions from climatic decrease in precipitation and from human irrigation development to a considerable total decrease in runoff (R) over Greece. This is on average -75 +/- 10 mm/year and is greatest for the Ionian catchment in the west (-119 +/- 18 mm/year) and the Peloponnese catchment in the south (-91 +/- 16 mm/year). For evapotranspiration (ET), a climate-driven decrease component and an irrigation-driven increase component have led to a net total increase of ET over Greece. This is on average 26 +/- 7 mm/year and is greatest for the Mainland catchment (29 +/- 7 mm/year) and the Aegean catchment in the east (28 +/- 6 mm/year). Overall, the resulting uncertainties in the water-balance constrained estimates of R and ET changes are smaller than the input data uncertainties.
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22.
  • Destouni, Georgia, et al. (författare)
  • Small unmonitored near-coastal catchment areas yielding large mass loading to the sea
  • 2008
  • Ingår i: Global Biogeochemical Cycles. ; 22:GB4003
  • Tidskriftsartikel (refereegranskat)abstract
    • Continental freshwater transports and loads excess nutrients and pollutants from various land surface sources into downstream inland and coastal water environments. This study shows that even small, hydrologically unmonitored near-coastal catchment areas may generate large nutrient and pollutant mass loading to the sea of a magnitude similar to or greater than monitored river loads. Systematic near-coastal gaps in the monitoring of freshwater discharges to the sea may therefore mislead the quantification of coastal mass loading significantly. A methodology is presented for quantifying the mass load contributions of all the different unmonitored pathways of hydrological mass transport to the coast, including unmonitored river parts, whole unmonitored streams, and submarine groundwater discharge. This can be used for guiding future efforts to improve monitoring so that it includes the essential hydrological pathways of nutrient and pollutant loading to the sea.
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23.
  • Destouni, Georgia, et al. (författare)
  • Water quality and ecosystem management : Data-driven reality check of effects in streams and lakes
  • 2017
  • Ingår i: Water resources research. - 0043-1397 .- 1944-7973. ; 53:8, s. 6395-6406
  • Tidskriftsartikel (refereegranskat)abstract
    • This study investigates nutrient-related water quality conditions and change trends in the first management periods of the EU Water Framework Directive (WFD; since 2009) and Baltic Sea Action Plan (BASP; since 2007). With mitigation of nutrients in inland waters and their discharges to the Baltic Sea being a common WFD and BSAP target, we use Sweden as a case study of observable effects, by compiling and analyzing all openly available water and nutrient monitoring data across Sweden since 2003. The data compilation reveals that nutrient monitoring covers only around 1% (down to 0.2% for nutrient loads) of the total number of WFD-classified stream and lake water bodies in Sweden. The data analysis further shows that the hydro-climatically driven water discharge dominates the determination of waterborne loads of both total phosphorus and total nitrogen across Sweden. Both water discharge and the related nutrient loads are in turn well correlated with the ecosystem status classification of Swedish water bodies. Nutrient concentrations do not exhibit such correlation and their changes over the study period are on average small, but concentration increases are found for moderate-to-bad status waters, for which both the WFD and the BSAP have instead targeted concentration decreases. In general, these results indicate insufficient distinction and mitigation of human-driven nutrient components in inland waters and their discharges to the sea by the internationally harmonized applications of the WFD and the BSAP. The results call for further comparative investigations of observable large-scale effects of such regulatory/management frameworks in different parts of the world.
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24.
  • Elmhagen, Bodil, et al. (författare)
  • Interacting effects of change in climate, human population, land use, and water use on biodiversity and ecosystem services
  • 2015
  • Ingår i: Ecology and Society. - 1708-3087. ; 20:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Human population growth and resource use, mediated by changes in climate, land use, and water use, increasingly impact biodiversity and ecosystem services provision. However, impacts of these drivers on biodiversity and ecosystem services are rarely analyzed simultaneously and remain largely unknown. An emerging question is how science can improve the understanding of change in biodiversity and ecosystem service delivery and of potential feedback mechanisms of adaptive governance. We analyzed past and future change in drivers in south-central Sweden. We used the analysis to identify main research challenges and outline important research tasks. Since the 19th century, our study area has experienced substantial and interlinked changes; a 1.6 degrees C temperature increase, rapid population growth, urbanization, and massive changes in land use and water use. Considerable future changes are also projected until the mid-21st century. However, little is known about the impacts on biodiversity and ecosystem services so far, and this in turn hampers future projections of such effects. Therefore, we urge scientists to explore interdisciplinary approaches designed to investigate change in multiple drivers, underlying mechanisms, and interactions over time, including assessment and analysis of matching-scale data from several disciplines. Such a perspective is needed for science to contribute to adaptive governance by constantly improving the understanding of linked change complexities and their impacts.
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26.
  • Goovaerts, Tony, et al. (författare)
  • Continuing education : preparing patients to choose a renal replacement therapy.
  • 2015
  • Ingår i: Journal of Renal Care. - : Wiley. - 1755-6678 .- 1755-6686. ; 41:1, s. 62-75
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Patients with progressive chronic kidney disease face a series of treatment decisions that will impact the quality of life of themselves and their family. Renal replacement therapy option education (RRTOE), generally provided by nurses, is recommended by international guidelinesOBJECTIVES: To provide nurses with advice and guidance on running RRTOE.DESIGN: A consensus conference.PARTICIPANTS: Four nurses, 5 nephrologists and 1 clinical psychologist (9 renal units; 6 European countries) from units that had extensive experience in RRTOE or were performing research in this field.APPROACH: Experts brainstormed and discussed quality standards for the education team, processes, content/topics, media/material/funding and quality measurements for RRTOE.RESULTS: Conclusions and recommendations from these discussions that are particularly pertinent to nurses are presented in this paper.CONCLUSIONS: Through careful planning and smooth interdisciplinary cooperation, it is possible to implement an education and support programme that helps patients choose a form of RRT that is most suited to their needs. This may result in benefits in quality of life and clinical outcomes.APPLICATION TO PRACTICE: There are large differences between renal units in terms of resources available and the demographics of the catchment area. Therefore, nurses should carefully consider how best to adapt the advice offered here to their own situation. Throughout this process, it is crucial to keep in mind the ultimate goal - providing patients with the knowledge and skill to make a modality choice that will enhance their quality of life to the greatest degree.
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27.
  • Isnard Bagnis, Corinne, et al. (författare)
  • Quality standards for predialysis education : results from a consensus conference
  • 2015
  • Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press. - 0931-0509 .- 1460-2385. ; 30:7, s. 1058-1066
  • Tidskriftsartikel (refereegranskat)abstract
    • This position statement was compiled following an expert meeting in March 2013, Zurich, Switzerland. Attendees were invited from a spread of European renal units with established and respected renal replacement therapy option education programmes. Discussions centred around optimal ways of creating an education team, setting realistic and meaningful objectives for patient education, and assessing the quality of education delivered.
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28.
  • Jaramillo, Fernando, et al. (författare)
  • Multimethod assessment of evapotranspiration shifts due to non-irrigated agricultural development in Sweden
  • 2013
  • Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 484, s. 55-62
  • Tidskriftsartikel (refereegranskat)abstract
    • During the 20th century, Sweden underwent a persistent agricultural development. In this study, we use and combine historical hydroclimatic and agricultural data to investigate how this large scale change of land use, and subsequent intensification of crop production, affected regional hydrology in two adjacent Swedish drainage basins. We find a main increase of evapotranspiration (ET) as cultivated area and/or crop production increased during the period 1901-1940. Thereafter, ET stabilized at a new higher level. Comparison between the data given, water balance constrained ET quantification (ETwb), and a range of different comparative estimates of purely climate driven ET (ETclim) shows that only 31% of the steep 1901-1940 increase of ETwb can be explained by climate change alone. The remaining 69% of this ETwb shift, which occurred in both investigated drainage basins, is instead explainable to large degree by the regional land use conversion from seminatural grasslands to cultivated land and associated enhanced productivity of herbaceous species.
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29.
  • Jarsjö, Jerker, et al. (författare)
  • Hydrological responses to climate change conditioned by historic alterations of land use and water use
  • 2012
  • Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 16:5, s. 1335-1347
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper quantifies and conditions expected hydrological responses in the Aral Sea Drainage Basin (ASDB; occupying 1.3% of the earth's land surface), Central Asia, to multi-model projections of climate change in the region from 20 general circulation models (GCMs). The aim is to investigate how uncertainties of future climate change interact with the effects of historic human re-distributions of water for land irrigation to influence future water fluxes and water resources. So far, historic irrigation changes have greatly amplified water losses by evapotranspiration (ET) in the ASDB, whereas 20th century climate change has not much affected the regional net water loss to the atmosphere. Results show that errors in temperature (T) and precipitation (P) from single GCMs have large influence on projected change trends (for the period 2010-2039) of river runoff (R), even though the ASDB is spatially well resolved by current GCMs. By contrast, observed biases in GCM ensemble mean results have relatively small influence on projected R change trends. Ensemble mean results show that projected future climate change will considerably increase the net water loss to the atmosphere. Furthermore, the ET response strength to any future T change will be further increased by maintained (or increased) irrigation practices, which shows how climate change and water use change can interact in modifying ET (and R). With maintained irrigation practices, R is likely to decrease to near-total depletion, with risk for cascading ecological regime shifts in aquatic ecosystems downstream of irrigated land areas. Without irrigation, the agricultural areas of the principal Syr Darya river basin could sustain a 50% higher T increase (of 2.3 A degrees C instead of the projected 1.5 A degrees C until 2010-2039) before yielding the same consumptive ET increase and associated R decrease as with the present irrigation practices.
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30.
  • Jarsjö, Jerker, et al. (författare)
  • Solute transport in coupled inland – coastal water systems : General conceptualisation and application to Forsmark
  • 2008
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • We formulate a general theoretical conceptualisation of solute transport from inland sources to downstream recipients, considering main recipient load contributions from all different nutrient and pollutant sources that may exist within any catchment. Since the conceptualisation is model-independent, its main hydrological factors and mass delivery factors can be quantified on the basis of inputs to and outputs from any considered analytical or numerical model. Some of the conceptually considered source contribution and transport pathway combinations are however commonly neglected in catchment-scale solute transport and attenuation modelling, in particular those related to subsurface sources, diffuse sources at the land surface and direct groundwater transport into the recipient. The conceptual framework provides a possible tool for clarification of underlying and often implicit model assumptions, which can be useful for e.g. inter-model comparisons in SKB’s site investigation or safety assessment programmes. In order to further clarify and explain research questions that may be of particular importance for transport pathways from deep groundwater surrounding a repository, we concretise and interpret some selected transport scenarios for model conditions in the Forsmark area. Possible uncertainties in coastal discharge predictions (that underpin all transport results), related to uncertain spatial variation of evapotranspiration within the catchment, were shown to be small for the relatively large, focused surface water discharges from land to sea, because local differences were averaged out along the length of the main water flow paths. In contrast, local flux values within the diffuse groundwater flow field from land to sea are more uncertain, although estimates of mean values and total sums of submarine groundwater discharge (SGD) along some considerable coastline length may be robust. The present results show that 80% to 90% of the total coastal discharge of Forsmark occurred through focused flows in visible streams, whereas the remaining 10% to 20% was diffuse and occurring through submarine groundwater discharge (SGD), small transient streams and/ or coastal wetlands. Regarding transport quantifications, hydrogeochemical characteristics and pollution source loads may generally differ between larger, monitored catchments and smaller unmonitored coastal catchments. Since national hydrological monitoring data systematically exclude smaller, coastal catchments, they may not be representative for conditions in Forsmark (or Simpevarp). This emphasises the importance of extending in time the recently started hydrological and hydrogeochemical data series in the Forsmark and Simpevarp coastal catchment areas, since they are in effect unmonitored from a hydrological viewpoint, due to the lack of extended discharge time series. In the performed initial demonstration analysis of solute transport pathways from deep groundwater to recipients at the surface, we considered the main scenarios: (I) transport in the quaternary deposits/bedrock interface zone only (assuming that the deep groundwater transport pathway to the coast excludes the inland surface water system), and (II) transport in the coupled groundwater-surface water system. Considering mean travel times from each model cell to the coast, and disregarding travel times in the deep bedrock domain itself (which may be added to the here presented values), results show that travel times in scenario (II) were less than 4 years in 90% of the considered model area (i.e., the Forsmark catchment area). Travel times were longer in scenario (I) with values higher than 10 years in 40% of the catchment area. These results are based on the assumption that the pathways do not go through zones of near-stagnant groundwater (found e.g. below Lake Bolundsfjärden, Lake Eckarfjärden and Lake Gällsboträsket in Forsmark). If they would do so (and the above assumption is violated), results show that travel times can be considerably longer, for instance exceeding 400 years in half of the model area in scenario (I). Considering possible solute attenuation (caused by e.g. biogeochemical reactions or decay) along the hydrological transport pathways to inland surface waters and to the coast, we estimate solute mass delivery factors, representing the fraction of mass released in a cell that reaches the considered recipient. Results showed that average delivery factors, representing the whole catchment and equalling expected delivery factors in the probabilistic case, can exhibit considerable differences between transport pathway scenarios (I) and (II). However, the magnitude of the differences in average delivery factors (between transport pathway scenarios as well as between considered release points) depends on the actual attenuation rates (i.e., l-values). This is because for low l (for Forsmark: l<0.01 year-1), practically all mass reaches the coast regardless of release point and scenario, and for high l (for Forsmark: l>10 year-1) only a small fraction of the mass reaches the coast regardless of release point and scenario. The above results imply that, in general, mass delivery factors to recipients are sensitive to both pathways and entrance points or areas in the quaternary deposits of Forsmark, with for instance a remaining key question being to which extent the deep groundwater transport pathway to the coast includes the surface water system and /or quaternary deposits/bedrock interface zone. However, given more specific sub-catchment areas (e.g., of biosphere objects of interest) and possible ranges of attenuation rates (of compounds of interest) from parallel studies, the present analyses also show that robust predictions regarding e.g. mass delivery can in some cases be obtained despite considerable pathway and entrance point uncertainties. Because such cases then can be excluded from further investigation, it appears that specific transport analyses that considers relevant combinations of possible release points, transport pathway scenarios and attenuation rates can be used for delimiting specific priority regions, where remaining uncertainties are high and further experimental investigations and/or monitoring hence may be needed to reduce the uncertainties.
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31.
  • Keller, Annika, et al. (författare)
  • Mutations in the gene encoding PDGF-B cause brain calcifications in humans and mice
  • 2013
  • Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:9, s. 1077-
  • Tidskriftsartikel (refereegranskat)abstract
    • Calcifications in the basal ganglia are a common incidental finding and are sometimes inherited as an autosomal dominant trait ( idiopathic basal ganglia calcification (IBGC)). Recently, mutations in the PDGFRB gene coding for the platelet-derived growth factor receptor beta (PDGF-R beta) were linked to IBGC. Here we identify six families of different ancestry with nonsense and missense mutations in the gene encoding PDGF-B, the main ligand for PDGF-R beta. We also show that mice carrying hypomorphic Pdgfb alleles develop brain calcifications that show age-related expansion. The occurrence of these calcium depositions depends on the loss of endothelial PDGF-B and correlates with the degree of pericyte and blood-brain barrier deficiency. Thus, our data present a clear link between Pdgfb mutations and brain calcifications in mice, as well as between PDGFB mutations and IBGC in humans.
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32.
  • Koussis, A. D., et al. (författare)
  • Cost-efficient management of coastal aquifers via recharge with treated wastewater and desalination of brackish groundwater: Application to the Akrotiri Basin and Aquifer, Cyprus
  • 2010
  • Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 55:7, s. 1234-1245
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate the general methodology for an intensive development of coastal aquifers, described in a companion paper, through its application to the management of the Akrotiri aquifer, Cyprus. The Zakaki area of that aquifer, adjacent to Lemessos City, is managed such that it permits a fixed annual agricultural water demand to be met, as well as and a fraction of the water demand of Lemessos, which varies according to available surface water. Effluents of the Lemessos wastewater treatment plant are injected into the aquifer to counteract the seawater intrusion resulting from the increased pumping. The locations of pumping and injection wells are optimized based on least-cost, subject to meeting the demand. This strategy controls sea intrusion so effectively that desalting of only small volumes of slightly brackish groundwater is required over short times, while ∼2.3 m3 of groundwater is produced for each 1 m3 of injected treated wastewater. The cost over the 20-year period 2000-2020 of operation is ∼40 M€ and the unit production cost of potable water is under 0.2 €/m3. The comparison between the deterministic and stochastic analyses of the groundwater dynamics indicates the former as conservative, i.e. yielding higher groundwater salinity at the well. The Akrotiri case study shows that the proposed aquifer management scheme yields solutions that are preferable to the widely promoted seawater desalination, also considering the revenues from using the treated wastewater for irrigation.
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33.
  • Koussis, A. D., et al. (författare)
  • Cost-efficient management of coastal aquifers via recharge with treated wastewater and desalination of brackish groundwater: General framework
  • 2010
  • Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 55:7, s. 1217-1233
  • Tidskriftsartikel (refereegranskat)abstract
    • Semi-arid coastal zones often suffer water-stress, as water demand is high and markedly seasonal, due to agriculture and tourism. Driven by scarcity of surface water, the communities in semi-arid coastal regions turn to aquifers as prime water source; but intensive exploitation of coastal aquifers causes seawater intrusion, which degrades the quality of groundwater. The cost-efficient and sustainable development of coastal aquifers can be achieved through a holistic management scheme which combines two non-traditional water sources: (a) saltwater, to be treated to the desired quality, and (b) wastewater, to be re-claimed to augment aquifer recharge for control of seawater intrusion, and also to meet certain demands. This management scheme is based on the idea that it is cost-advantageous to: (i) desalt brackish groundwater, instead of seawater, as the former requires far less energy, and (ii) to re-use wastewater at only the differential cost to any treatment already practiced. In this paper, we present the general framework of the proposed management scheme, and a decision aid tool (DAT) which has been developed to assist decision makers to explore the scheme's decision space. The DAT uses cost as optimization criterion to screen various management scenarios, via modelling of the dynamic natural-engineered system behaviour, and identifies those cost-efficient ones that meet the water demand and achieve aquifer protection.
  •  
34.
  • Mallo-Abreu, Ana, et al. (författare)
  • Nitrogen-Walk Approach to Explore Bioisosteric Replacements in a Series of Potent A(2B) Adenosine Receptor Antagonists
  • 2020
  • Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 63:14, s. 7721-7739
  • Tidskriftsartikel (refereegranskat)abstract
    • A systematic exploration of bioisosteric replacements for furan and thiophene cores in a series of potent A(2B)AR antagonists has been carried out using the nitrogen-walk approach. A collection of 42 novel alkyl 4-substituted-2-methyl-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxylates, which contain 18 different pentagonal heterocyclic frameworks at position 4, was synthesized and evaluated. This study enabled the identification of new ligands that combine remarkable affinity (K-i < 30 nM) and exquisite selectivity. The structure-activity relationship (SAR) trends identified were substantiated by a molecular modeling study, based on a receptor-driven docking model and including a systematic free energy perturbation (FEP) study. Preliminary evaluation of the CYP3A4 and CYP2D6 inhibitory activity in optimized ligands evidenced weak and negligible activity, respectively. The stereospecific interaction between hA(2B)AR and the eutomer of the most attractive novel antagonist (S)-18g (K-i = 3.66 nM) was validated.
  •  
35.
  • Persson, Klas, 1979-, et al. (författare)
  • Propagation of environmental risk from contaminant transport through groundwater and stream networks
  • 2008
  • Ingår i: Risk Analysis VI.
  • Konferensbidrag (refereegranskat)abstract
    • We use a Lagrangian stochastic advective-reactive (LaSAR) approach to model coupled groundwater and surface water contaminant transport. In this approach, physical (advective) solute travel time distributions constitute main functions for the contaminant transport representation. In a specific catchment area case study, we show how these travel time distributions, for separate groundwater and stream network systems and for the linked groundwater-stream systems of whole catchments, can be modelled and quantified from available field data. We further use the LaSAR modelling approach in an extreme-scenario methodology for investigating how the risk (probability) of concentrations exceeding given environmental or health-based concentration limits may propagate downstream of a contaminant source for various spatial source extents and contaminant release magnitudes and dynamics under different aquifer conditions. Results show that the average relation between characteristic advective transport and natural attenuation time scales is essential and in some (with results identifying also in which) cases sufficient information for assessing if and where this risk may decline below acceptable levels downstream of the source zone. The presented general quantification methodology and specific exemplification results may provide useful guidelines for emergency remediation of contaminated land sites and for prioritisation decisions and scoping calculations to focus further investigations of long-term remediation options on critical site and contaminant parameters. Keywords: contaminated land, solute transport, stochastic modelling, environmental risk analysis, GIS.
  •  
36.
  • Persson, Klas, et al. (författare)
  • Propagation of environmental risk from contaminant transport through groundwater and stream networks
  • 2008
  • Ingår i: Risk analysis VI. ; , s. 55-64
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • We use a Lagrangian stochastic advective-reactive (LaSAR) approach to model coupled groundwater and surface water contaminant transport. In this approach, physical (advective) solute travel time distributions constitute main functions for the contaminant transport representation. In a specific catchment area case study, we show how these travel time distributions, for separate groundwater and stream network systems and for the linked groundwater-stream systems of whole catchments, can be modelled and quantified from available field data. We further use the LaSAR modelling approach in an extreme-scenario methodology for investigating how the risk (probability) of concentrations exceeding given environmental or health-based concentration limits may propagate downstream of a contaminant source for various spatial source extents and contaminant release magnitudes and dynamics under different aquifer conditions. Results show that the average relation between characteristic advective transport and natural attenuation time scales is essential and in some (with results identifying also in which) cases sufficient information for assessing if and where this risk may decline below acceptable levels downstream of the source zone. The presented general quantification methodology and specific exemplification results may provide useful guidelines for emergency remediation of contaminated land sites and for prioritisation decisions and scoping calculations to focus further investigations of long-term remediation options on critical site and contaminant parameters.
  •  
37.
  • Prieto, Carmen, et al. (författare)
  • Climate-Driven Phenological Change : Developing Robust Spatiotemporal Modeling and Projection Capability
  • 2015
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Our possibility to appropriately detect, interpret and respond to climate-driven phenological changes depends on our ability to model and predict the changes. This ability may be hampered by non-linearity in climate-phenological relations, and by spatiotemporal variability and scale mismatches of climate and phenological data. A modeling methodology capable of handling such complexities can be a powerful tool for phenological change projection. Here we develop such a methodology using citizen scientists' observations of first flight dates for orange tip butterflies (Anthocharis cardamines) in three areas extending along a steep climate gradient. The developed methodology links point data of first flight observations to calculated cumulative degree-days until first flight based on gridded temperature data. Using this methodology we identify and quantify a first flight model that is consistent across different regions, data support scales and assumptions of subgrid variability and observation bias. Model application to observed warming over the past 60 years demonstrates the model usefulness for assessment of climate-driven first flight change. The cross-regional consistency of the model implies predictive capability for future changes, and calls for further application and testing of analogous modeling approaches to other species, phenological variables and parts of the world.
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38.
  • Prieto, Carmen, 1972- (författare)
  • Groundwater-Seawater Interactions : Seawater Intrusion, Submarine Groundwater Discharge and Temporal Variability and Randomness Effects
  • 2005
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Fresh groundwater quality and availability in coastal areas is affected by seawater intrusion into coastal aquifers, and coastal water quality and ecosystem status may be significantly affected by groundwater pollutants that are transported into coastal waters by submarine groundwater dis-charge (SGD). This thesis uses an overall regional perspective for investigating: i) seawater intru-sion and its possible control in sustainable coastal groundwater management; ii) SGD and its relevant quantification as one interacting part among the diverse main regional pathways of freshwater and tracer/pollutant inputs from land to sea; and iii) the integrated system functioning of both i) and ii) as main components of the same coastal groundwater system. Results show that intensive pumping rates may be maintained for a long time before major re-gional seawater intrusion problems are recognized by too high salinities in pumped groundwater. After such late recognition, pumping wells are no longer useful and a common strategy of mov-ing groundwater pumping further upstream from the coast only increases the extent of the salt-water intrusion zone into the aquifer. An alternative strategy may be to control seawater intrusion through artificial groundwater recharge, for instance by sufficiently treated wastewater, which may considerably reduce long-term trends of salinity increase in pumped groundwater, even for small artificial recharge rates compared to pumping rates. In general, account for natural spatial-temporal variability and randomness may be essential for relevant prediction of groundwater dynamics for management purposes. Spatial and temporal randomness effects, however, may not be additive, but rather largely overlapping, with either spatial or temporal randomness being the dominating part that must be accounted for in predictive groundwater dynamics calculations. Aquifer depth is identified as an important control parameter in this context, yielding much greater temporal randomness effects in shallow than in deep aquifers. Combined simulation results suggest a simple, approximately linear regional relationship between total SGD and its hydrologically determined freshwater component. Tidal oscillation may signifi-cantly affect such linear dependence of steady-state SGD, but primarily for low SGD conditions. High SGD appears to depend mainly on a dominant freshwater component, which effectively counteracts density-driven flow of seawater into the aquifer and thus decreases also effects of sea-level oscillation on the seawater component of total SGD. Comparative analysis between different SGD estimation methods in different reported high-SGD regions of the world indicates possible anomalously large regional SGD estimation from tracer concentrations in coastal waters, by confusing different main pathways of groundwater flow and pollutant inputs to the sea.
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39.
  •  
40.
  • Prieto, Carmen, et al. (författare)
  • Is submarine groundwater discharge predictable?
  • 2011
  • Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 38, s. L01402-
  • Tidskriftsartikel (refereegranskat)abstract
    • The contribution of submarine groundwater discharge (SGD) to the total hydrological discharges to the sea may be large but has been difficult to quantify. We have tested the applicability and generality of a suggested linear relationship between annual average total SGD and its fresh groundwater component against various SGD simulation results and field data. This relationship is found to constitute a general attractor for hydrologically simulated and directly measured SGD values across a wide range of conditions and world regions. But these consistent SGD quantifications differ systematically and largely from indirect SGD interpretations of tracers in seawater. This is an essential gap between inland- and sea-based methods of SGD estimation that needs to be bridged.
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41.
  • Prieto, Carmen (författare)
  • Modelling Freshwater-Seawater Interactions in Coastal Aquifers : Long-term Trends and Temporal Variability Effects
  • 2001
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Over-exploitation of coastal aquifers causes seawaterintrusion and eventually contamination of groundwater wells inmany parts of the world. Desalination of brackish water andartificial recharge of treated wastewater may then be asustainable strategy for managing groundwater supply inwater-stressed regions. A common characteristic of many coastalareas in Southern Europe is that they are seasonallywater-stressed due to that most of the annual water demand isconcentrated to a few summer months, whereas naturalgroundwater recharge takes place primarily during the wintermonths. This thesis investigates long-term salinity trends inpumped groundwater, and the effects of temporal variations inpumping, as well as in artificial and natural recharge ratesand boundary conditions on the dynamics of saltwater intrusionin two Mediterranean coastal aquifers, located in Israel andthe island of Rhodes, Greece. Furthermore, the thesis presentsa rational methodology for stochastic modelling and uncertaintyanalysis of seawater intrusion, which explicitly accounts forspatial aquifer heterogeneity and temporal randomness innatural recharge and boundary conditions. The methodology isspecifically applied to the Israel and Rhodes case studies, aswell as to an additional coastal aquifer in Cyprus.Numerical simulation of freshwater-seawater interactionsassuming constant sinks and sources may introduce deviations ofless than 10% in long-term predictions of salinity in pumpedgroundwater, relative to the mean salinity resulting fromseasonally variable management scenarios. In the short-term, upto 25 years after start of pumping and recharge activities,however, the assumption of constant management scenarios maylead to considerable (50-60%) underestima tion of maximumsalinity values under seasonally variable conditions. Suchdeviations may affect the optimal design, function andefficiency of brackish groundwater desalination plants duringthe common planning period of 25 years. Therefore, seasonalvariability must be accounted for in predictive modelling ofgroundwater salinity, if the selected management strategy is tosupply the water demand by desalinating brackish groundwater.However, possible effects of seasonal variability should alsobe assessed in comparison with possible inter-annualvariability, which may have even greater effects.The uncertainty analysis applied to three case studiesshowed that predicted salinity from deterministic simulationscan not be expected to accurately reproduce correspondingexpected concentrations of stochastic simulations.Accounting for temporal randomness, in addition to randomspatial heterogeneity, increases the difference betweendeterministic salinity results and expected salinity fromstochastic simulations. In contrast, the salinity standarddeviationdoes not increase very much by temporal randomness inaddition to spatial one. The resulting salinity coefficient ofvariation is site specific, but is also generally not very muchincreased by temporal randomness in addition to spatialrandomness.Keywords:seawater intrusion, seasonal variability,artificial recharge, spatial and temporal randomness
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42.
  • Prieto, Carmen, et al. (författare)
  • Seawater intrusion in coastal aquifers: Effects of seasonal variations in extraction and recharge rates
  • 2001
  • Ingår i: SWICA M3 Cyber Proceedings of First International Conference on Saltwater Intrusion and Coastal Aquifers - Monitoring, Modeling and Management. ; , s. 1-11
  • Konferensbidrag (refereegranskat)abstract
    • Over-exploitation of coastal aquifers causes seawater intrusion and eventuallycontamination of groundwater wells in many parts of the world. Artificial recharge oftreated wastewater can be used to avoid or control seawater intrusion. A commoncharacteristic of many coastal areas in Southern Europe is that most of the annualwater demand, and hence the amount of water that can be used for artificial recharge,is concentrated to a few summer months, whereas natural groundwater recharge takesplace during the winter months. This paper addresses the effects of seasonal variationsin pumping, as well as in artificial and natural recharge rates on the dynamics ofsaltwater intrusion and especially on the evolution of salinity in extractedgroundwater. Specifically, numerical simulations are performed to examine theseasonal variability effects for a given set of extraction and recharge locations, but forscenarios with different artificial recharge rates. Parameter values for describing theaquifer and its hydraulic-hydrological properties are taken from a coastal aquifer inIsrael. We show that predicted salinity in extracted groundwater under assumedtemporally constant pumping and recharge conditions differs from the mean value ofsalinity under seasonally variable conditions. For long-term predictions, theassumption of temporally constant conditions may yield relatively small (less than10%) over- or underestimation of average salinity during the periodic steady-statestage that results from seasonally variable conditions. For short-term predictions, upto the common planning period of 25 years after starting a new groundwatermanagement practice, the same assumption may lead to considerable (50-55%)underestimation of maximum salinity values under seasonally variable conditions.
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43.
  • Prieto, Carmen, et al. (författare)
  • The influence of temporal hydrological randomness on seawater intrusion in coastal aquifers
  • 2006
  • Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 330:1-2, s. 285-300
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate general effects of temporal hydrological randomness on seawater intrusion in coastal aquifers, using a 2D conceptuatization and model parameterization of three coastal aquifer zones on the Mediterranean Sea. These three aquifer cases represent quite different examples of hydrogeological conditions and temporal hydrological and groundwater management variability and statistics. A general result for all aquifer cases is that the effects of temporal randomness on expected salinity in pumped groundwater are greater for spatially homogeneous than for spatially heterogeneous aquifer representations. We quantify also prediction uncertainty around expected groundwater salinity, in terms of the salinity standard deviation and coefficient of variation (CV) in the different aquifer cases. In general, the salinity CV appears to depend much more on the aquifer depth than on the input temporal fluctuation statistics of each aquifer case. Aquifer depth may thus be a main indicator for resulting prediction uncertainty in salinity of pumped groundwater due to temporal hydrological randomness.
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44.
  • Prieto Rábade, Miguel, et al. (författare)
  • Model for the assessment of bond in corroded steel ribbed bars
  • 2022
  • Konferensbidrag (refereegranskat)abstract
    • The aim of the present paper is to further validate a model proposed for assessing bond strength in corroded and non-corroded steel bars. The model was obtained by applying multiple linear regression analysis to an initial database obtained from literature containing over 650 bond tests: 372 with corroded steel bars. In this paper, a second stage for further validating the model has been conducted with new database consisting of 131 new tests of bond with corroded steel bars resulting in a final database of 500 tests of bond with corroded reinforcing steel bars. In this model, bond strength is considered as an average stress on the nominal surface of a straight length of a bar over the bond length. The corrosion effect is considered using the cross-section loss (% Cor) considered as uniform corrosion along the bonded length of the bar. In addition to the cross-section loss, corrosion effect in bond is additionally considered with an additional variable that implicitly includes the effect of cracking depending on the range of cross section loss, bond condition and presence of transverse reinforcement. In the paper, the former formulation proposed in is compared with the formulation adapted with rounded coefficients for the former database, the new database and the combined database with different statistical criteria to compare the accuracy of the bond strength predictions obtained with the model. Finally, the predictions of the model show a good fitting with the experimental results with the new database and also have a low scatter. This is showing its utility in the safety assessment of bond strength in reinforced concrete members.
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45.
  • Prieto-Velasco, Mario, et al. (författare)
  • Predialysis education in practice : a questionnaire survey of centres with established programmes.
  • 2014
  • Ingår i: BMC research notes. - : Springer Science and Business Media LLC. - 1756-0500. ; 7, s. 730-
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: There is growing evidence that renal replacement therapy option education (RRTOE) can result in enhanced quality of life, improved clinical outcomes, and reduced health care costs. However, there is still no detailed guidance on the optimal way to run such programmes. To help address this knowledge gap, an expert meeting was held in March 2013 to formulate a position statement on optimal ways to run RRTOE. Experts were selected from units that had extensive experience in RRTOE or were performing research in this field. Before the meeting, experts completed a pilot questionnaire on RRTOE in their own units. They also prepared feedback on how to modify this questionnaire for a large-scale study.METHODS: A pilot, web-based questionnaire was used to obtain information on: the renal unit and patients, the education team, RRTOE processes and content, how quality is assessed, and funding.RESULTS: Four nurses, 5 nephrologists and 1 clinical psychologist (9 renal units; 6 EU countries) participated. Nurses were almost always responsible for organising RRTOE. Nephrologists spent 7.5% (median) of their time on RRTOE. Education for the patient and family began several months before dialysis or according to disease progression. Key topics such as the 'impact of the disease' were covered by every unit, but only a few units described all dialysis modalities. Visits to the unit were almost always arranged. Materials came in a wide variety of forms and from a wide range of sources. Group education sessions were used in 3/9 centres. Expectations on the timing of patients' decisions on modality and permanent access differed substantially between centres. Common quality assurance measures were: patient satisfaction, course attendance, updated materials. Only 1 unit had a dedicated budget.CONCLUSIONS: There were substantial variations in how RRTOE is run between the units. A modified version of this questionnaire will be used to assess RRTOE at a European level.
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46.
  • Quintana-Lacaci, Guillermo, et al. (författare)
  • Hints of the Existence of C-rich Massive Evolved Stars
  • 2019
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 876:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We aim to study the properties of a particular type of evolved stars, C-rich evolved stars with high expansion velocities. For this purpose we have focused on the two best studied objects within this group, IRC+10401 and AFGL 2233. We focused on determining their luminosity by studying their spectral energy distribution. Also, we have obtained single-dish line profiles and interferometric maps of the CO J - 1-0 and J = 2-1. emission lines for both objects. We have modeled this emission using a LVG radiative transfer code to determine the kinetic temperature and density profiles of the gas ejected by these stars. We have found that the luminosities obtained for these objects (log(L/L-circle dot). =. 4.1 and 5.4) locate them in the domain of the massive asymptotic giant branch stars (AGBs) and the red supergiant stars (RSGs). In addition, the mass-loss rates obtained (1.5. x. 10(-5)-6. x 10(-3)M(circle dot) yr(-1)) suggest that while IRC+ 10401 might be an AGB star, AFGL 2233 could be an RSG star. All these results, together with those from previous works, suggest that both objects are massive objects, IRC+10401 a massive evolved star with M-init similar to 5-9M(circle dot). which could correspond to an AGB or an RSG and AFGL 2233 an RSG with M-init similar to 20M(circle dot), which would confirm the existence of massive C-rich evolved stars. Two scenarios are proposed to form these types of objects. The first one is capable of producing high-mass AGB stars up to similar to 8M(circle dot). and the second one is capable of forming C-rich RSGs like AFGL 2233.
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47.
  • Shibuo, Yoshihiro, et al. (författare)
  • Climate change and irrigation expansion: Land-water-atmosphere interactions in the Aral Sea basin
  • 2007
  • Ingår i: Proceedings of the third international conference on climate and water. - 9789521127908 ; , s. 430-435
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The Aral Sea drainage basin (ASDB), covering an area of totally 1,874,000 km2 in Central Asia, has experienced an enormous expansion of irrigated agriculture during the past century. Presently, water is diverted from the two principal rivers, Amu Darya and Syr Darya, to such an extent that the Aral Sea receives only about 10% of its former 70 km3 annual freshwater input through river discharge. As a result, the Aral Sea started to shrink in the 1960’s, and is expected to continue to shrink in the foreseeable future accompanied by desertification of surrounding areas. In addition to these water diversions, however, regional climate may also have changed significantly in the region since the 1960’s as a regional manifestation of global climate change over this period. We investigate here land -water-atmosphere interactions in the Aral Sea basin using a basin-scale hydrological balance modelling approach, in which the locally created runoff (i.e., precipitation minus evapotranspiration) is estimated using precipitation and temperature as driving boundary conditions. The runoff is routed through a flow network derived from a 30” 30” digital elevation model. Results show that the major irrigation areas in the ASDB yields a considerable 17% increase in evapotranspiration flux from land to the atmosphere, which is not balanced by a corresponding increase in observed precipitation. Despite the expected surface cooling effects of increased evapotranspiration, temperature data shows that the basin manifestation of global climate change appears to be a warming trend. In addition, our results show specifically that more than 90% of the irrigation water input in the ASDB returns to the atmosphere by evapotranspiration, which is at the high end of previous estimates. This indicates possible non-local and climate driving effects of water management that are relatively large.
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48.
  •  
49.
  • Thorslund, Josefin, et al. (författare)
  • Wetlands as large-scale nature-based solutions : Status and challenges for research, engineering and management
  • 2017
  • Ingår i: Ecological Engineering. - : Elsevier BV. - 0925-8574 .- 1872-6992. ; 108, s. 489-497
  • Tidskriftsartikel (refereegranskat)abstract
    • Wetlands are often considered as nature-based solutions that can provide a multitude of services of great social, economic and environmental value to humankind. Changes in land-use, water-use and climate can all impact wetland functions and services. These changes occur at scales extending well beyond the local scale of an individual wetland. However, in practical applications, engineering and management decisions usually focus on individual wetland projects and local site conditions. Here, we systematically investigate if and to what extent research has addressed the large-scale dynamics of landscape systems with multiple wetlands, hereafter referred to as wetlandscapes, which are likely to be relevant for understanding impacts of regional to global change. Although knowledge in many cases is still limited, evidence suggests that the aggregated effects of multiple wetlands in the landscape can differ considerably from the functions observed at individual wetland scales. This applies to provisioning of ecosystem services such as coastal protection, biodiversity support, groundwater level and soil moisture regulation, flood regulation and contaminant retention. We show that parallel and circular flow-paths, through which wetlands are interconnected in the landscape, may largely control such scale-function differences. We suggest ways forward for addressing the mismatch between the scales at which changes take place and the scale at which observations and implementation are currently made. These suggestions can help bridge gaps between researchers and engineers, which is critical for improving wetland function-effect predictability and management.
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