| 1. |
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| 2. |
- Jonsson, C. E., et al.
(författare)
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High-resolution diatom d18O records from two sub-Arctic high-altitude lakes in the Swedish Scandes
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Ingår i: Journal of Quaternary Science. - 0267-8179 .- 1099-1417.
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Tidskriftsartikel (refereegranskat)abstract
- Waters from high altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature, and relatively short hydraulic residence times, most high altitude lakes have lake water isotopic compositions (δ18Olake) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water d18O. Here we compare two high resolution δ18Odiatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900 to AD 1990 is characterized by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ18Odiatom as decreasing trends. Lowest δ18Odiatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 years the main factor affecting the δ18Odiatom signal in these sub-Arctic high altitude lakes with short residence times has been changes in amount of winter precipitation and that δ18Odiatom derived from high altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy.
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| 3. |
- Jonsson, C. E., et al.
(författare)
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Reconstructing past atmospheric circulation changes using oxygen isotopes in lake sediments from Sweden
- 2009
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Ingår i: Climate of the Past Discussions. - 1814-9340. ; 5:3, s. 1609-1644
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Tidskriftsartikel (refereegranskat)abstract
- Here we use lake sediment studies from Sweden to illustrate how Holocene-aged oxygen isotope records (from lakes located in different hydrological settings) can provide information about climate change. In particular changes in precipitation, atmospheric circulation and water balance. We highlight the importance of understanding the present and past lake hydrology, and the relationship between climate parameters and the oxygen isotopic composition of precipitation (d18Op) and lake waters (d18Olakewater) for interpretation of the oxygen isotopic record from the sediments (d18O). Both precipitation reconstructions from northern Sweden and water balance reconstructions from south and central Sweden show that the atmospheric circulation changed from zonal to a more meridional air flow over the Holocene. Superimposed on this Holocene trend are δ18Op minima resembling intervals of the negative phase of the North Atlantic Oscillation (NAO), thus suggesting that the climate of Northern Europe is strongly influenced by atmospheric and oceanic circulation changes over the North Atlantic.
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| 4. |
- Jonsson, C. E., et al.
(författare)
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Two diatom oxygen isotope records from Naimakka in northern Fennoscandia: implications for Holocene palaeohydrology and atmospheric circulation dynamics
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This study present past changes in lake water oxygen isotope composition (δ18Olakew) calculated from diatom oxygen isotope composition (δ18Odiatom) from two lake sediment records. The two sediment sequences (9500 and 2800 years) are from open-basin lakes, although with different hydrologies, and are located close to a meteorological station in Naimakka, Northern Fennoscandia. The isotope composition of lake waters was analysed to determine the modern regional hydrological setting. Our results show that changes in the isotope composition of precipitation (δ18Op) is the primary forcing mechanism decreasing or increasing the δ18Olakew values in both lakes. Changes in the isotope signals are interpreted as reflecting regional variations in atmospheric circulation and climatic seasonality. δ18Odiatom from Lake Keitjoru, covering the last 9500 years, shows a depletion trend of 1.3‰ from c. 8000 until around 1500 cal yr BP. This decrease is thought to be due to a long term decrease in the influence of a zonal airflow (strong westerlies, relatively high δ18Op) over Fennoscandia in favor of an increasing proportion of colder meridional airflow (weak westerlies, lower δ18Op) from the north. A synchronous shift to lower δ18O values was recorded in Lake Keitjoru and lake Oikojärvi around 700-600 cal yr BP (~AD 1250-1350), a time when European climate deteriorated into the “Little Ice Age”. We argue that a circulation pattern dominated by meridional airflow, with reduced westerlies over Northern Fennoscandia and high amounts of winter precipitation from southeast or north, replaced a zonal atmospheric circulation pattern at this time. The δ18Odiatom minima c. 400 and 50 cal yr BP (~AD 1550 and AD 1900) is likely also a response to shifts in circulation, which is also seen in lower summer temperatures at that time recorded in tree-rings and from pollen data. The fact that the same isotope shifts have been detected in δ18O records from hydrological different lakes lends support to our conclusion that these records reflect variations in atmospheric circulation pattern.
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| 5. |
- Orme, L. C., et al.
(författare)
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Climatic impacts on an Arctic lake since 1300 AD : a multi-proxy lake sediment reconstruction from Prins Karls Forland, Svalbard
- 2023
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Ingår i: Journal of Paleolimnology. - : Springer Science and Business Media LLC. - 0921-2728 .- 1573-0417. ; 69:3, s. 249-266
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Tidskriftsartikel (refereegranskat)abstract
- On the remote Arctic archipelago of Svalbard, there is increasing evidence of environmental impacts from climate change. The analysis of lake sedimentary records can be used to assess how strongly these recent changes have altered lake ecosystems. Sediments deposited during the last millennium from Lake Blokkvatnet, Prins Karls Forland, were analysed using a multiproxy approach, including stable isotope and X-ray fluorescence analysis. The results were interpreted as reflecting variability of (1) soil organic matter inwash, and potentially catchment and lake primary production, and (2) catchment weathering and erosion. Organic content began increasing after 1920 AD to the present, likely in response to warming. Earlier peaks of a similar magnitude occurred on three occasions since 1300 AD, with evidence indicating that these may have coincided with multidecadal-scale periods with higher temperatures, reduced sea ice and negative phases of the North Atlantic Oscillation. Catchment weathering and fluvial erosion began to increase around 1800 AD and peaked during the early twentieth century, potentially due to rising temperatures in autumn and winter causing increased liquid water availability. The records suggest that similar levels of erosion and weathering occurred between approximately 1300 and 1600 AD, spanning the transition from the Medieval Climate Anomaly to the Little Ice Age.
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| 6. |
- Rosqvist, G. C., et al.
(författare)
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North Atlantic region atmospheric circulation dynamics inferred from a late-Holocene lacustrine carbonate isotope record, northern Swedish Lapland
- 2007
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Ingår i: The Holocene. - 0959-6836 .- 1477-0911. ; 17:7, s. 867–873-
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Tidskriftsartikel (refereegranskat)abstract
- The first high-resolution record of climate variation based on the oxygen and carbon isotope composition of authigenic carbonate for northern Scandinavia is presented. Modern lake-water isotope data indicate that controls on its oxygen and hydrogen (δ18Ow and δDw) composition are unlikely to be evaporation or temperature, and its variations must therefore reflect changes in, or at the source of, precipitation. Substantial and persistent changes of the isotopic composition of the precipitation are required to change the mean annual isotope composition of lake surface water. For this reason we argue that the recorded changes were significant and that the recurrence of such changes would greatly affect future regional climate conditions in the North Atlantic region. Oxygen isotope (δ18O) minima occurring at ~ 200, 500, 1300, 1600 and at 2900 cal. yr BP all coincide with major peaks in North Atlantic ice rafted debris deposition. We suggest that the depletion events in δ18O cycles recorded in several lakes in northern Swedish Lapland are caused by the same climatic shifts as those noted in the North Atlantic marine records. This is because changes of atmospheric circulation pattern and the lower ocean and atmospheric temperatures associated with the IRD events help to explain why 18O depletion of precipitation occurred during these events. Our findings indicate that the recorded changes in North Atlantic ice drift and surface hydrography are coupled to changes in atmospheric circulation.
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| 7. |
- Berntsson, Annika, et al.
(författare)
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Late-Holocene temperature and precipitation changes in Vindelfjallen, mid-western Swedish Lapland, inferred from chironomid and geochemical data
- 2014
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 24:1, s. 78-92
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we present results from a palaeolimnological study from Lake Vuoksjavratje in the mountain tundra region in the Vindelfjallen Mountains, northwest Sweden. We suggest that the influence of precipitation may be one of the factors causing discrepancies between chironomid-based late-Holocene July temperature (JulyT) reconstructions from Fennoscandia. We combine quantitative temperature reconstruction using chironomids for the last 5100 years with qualitative analysis of chironomid composition and geochemical analyses, such as x-ray fluorescence (XRF), total organic carbon (TOC) and C/N analysis. The studied sequence is dated by Pb-210, Cs-137 and 11 C-14 datings from terrestrial macrofossils. The aim of the study was to use chironomids to reconstruct late-Holocene summer temperature variation on a multi-centennial to centennial timescale and to use geochemical data to identify periods during which the changes in chironomid composition might have been forced by environmental variables other than temperature, such as within lake processes or precipitation. Based on ordination techniques, and a comparison between chironomid-inferred JulyTs and changes in minerogenic sedimentation with regional temperature and wetness records, it is concluded that the JulyT signal was modulated by precipitation. The proxies indicate that both JulyT and annual precipitation have influenced the chironomid communities in Lake Vuoksjavratje, and that catchment-related processes caused by enhanced precipitation have overridden the summer temperature signal between 3000 and 2200 cal. yr BP, and between 1050 and 100 cal. yr BP.
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| 8. |
- Clason, Caroline C., et al.
(författare)
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Dye tracing to determine flow properties of hydrocarbon-polluted Rabots glaciar, Kebnekaise, Sweden
- 2015
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Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 19:6, s. 2701-2715
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Tidskriftsartikel (refereegranskat)abstract
- Over 11 000 L of kerosene was deposited on the surface of Rabots glaciar on the Kebnekaise Massif, northern Sweden, following the crash of a Royal Norwegian Air Force aircraft in March 2012. An environmental monitoring programme was subsequently commissioned, including a series of dye tracing experiments during the 2013 melt season, conducted to investigate the transport of pollutants through the glacier hydrological system. This experimental set-up provided a basis from which we could gain new insight into the internal hydrological system of Rabots glaciar. Results of dye tracing experiments reveal a degree of homogeneity in the topology of the drainage system throughout July and August, with an increase in efficiency as the season progresses, as reflected by decreasing temporary storage and dispersivity. Early onset of melting likely led to formation of an efficient, discrete drainage system early in the melt season, subject to decreasing sinuosity and braiding as the season progressed. Four distinct meltwater flow regimes are identified to summarize the temporal and spatial evolution of the system. Analysis of turbidity-discharge hysteresis further supports the formation of discrete, efficient drainage, with clockwise diurnal hysteresis suggesting easy mobilization of readily available sediments in channels. Dye injection immediately downstream of the pollution source zone reveals prolonged storage of dye followed by fast, efficient release. Twinned with a low dye recovery, and supported by sporadic detection of hydrocarbons in the proglacial river, we suggest that meltwater, and thus pollutants in solution, may be released periodically through an efficient, and likely pressurized, hydrological system within the upper reaches of the glacier.
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| 9. |
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| 10. |
- Dahlin, T., et al.
(författare)
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Geoelectrical resistivity monitoring for localizing gas at Landfills
- 2009
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Ingår i: Near Surface 2009 : 15th European Meeting of Environmental and Engineering Geophysics - 15th European Meeting of Environmental and Engineering Geophysics. - 9073781728 - 9789073781726
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Konferensbidrag (refereegranskat)abstract
- In order to assess the potential of electrical resistivity for imaging gas migration at landfills, two relatively well-known sites - one bioreactor landfill and a conventional landfill - have been monitored successively. A three-dimensional resistivity image could be constructed every two hour on both sites. Meteorological parameters were monitored at the same time, with one measurement taken every hour. Methane concentration was measured in the air at several occasions, the pore pressure was monitored at two locations and some relative estimations of moisture in the top layer were made at the second site. The results show imperfect but interesting correlations between the different parameters and give a hint of how the method could be refined. The resistivity depends on several parameters, but the areas where the resistivity is most variable seem to be clearly related to higher gas emissions.
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| 11. |
- Eichelmann, Fabian, et al.
(författare)
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Lipidome changes due to improved dietary fat quality inform cardiometabolic risk reduction and precision nutrition
- 2024
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Ingår i: Nature Medicine. - 1078-8956 .- 1546-170X. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Current cardiometabolic disease prevention guidelines recommend increasing dietary unsaturated fat intake while reducing saturated fats. Here we use lipidomics data from a randomized controlled dietary intervention trial to construct a multilipid score (MLS), summarizing the effects of replacing saturated fat with unsaturated fat on 45 lipid metabolite concentrations. In the EPIC-Potsdam cohort, a difference in the MLS, reflecting better dietary fat quality, was associated with a significant reduction in the incidence of cardiovascular disease (−32%; 95% confidence interval (95% CI): −21% to −42%) and type 2 diabetes (−26%; 95% CI: −15% to −35%). We built a closely correlated simplified score, reduced MLS (rMLS), and observed that beneficial rMLS changes, suggesting improved dietary fat quality over 10 years, were associated with lower diabetes risk (odds ratio per standard deviation of 0.76; 95% CI: 0.59 to 0.98) in the Nurses’ Health Study. Furthermore, in the PREDIMED trial, an olive oil-rich Mediterranean diet intervention primarily reduced diabetes incidence among participants with unfavorable preintervention rMLS levels, suggestive of disturbed lipid metabolism before intervention. Our findings indicate that the effects of dietary fat quality on the lipidome can contribute to a more precise understanding and possible prediction of the health outcomes of specific dietary fat modifications.
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| 12. |
- Hiselius, Lena Winslott, et al.
(författare)
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Gender Representation and Leadership in Local Transport Decision-Making Positions
- 2023
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Ingår i: Sustainability. - : Multidisciplinary Digital Publishing Institute (MDPI). - 2071-1050. ; 15:14
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to analyse and further capture nuances of gender representation in local political decision-making bodies, focusing on implications for transport policy. Since gender is highly relevant for both attitudes towards transport policy as well as political votes, data on the gender and political colour of executives (members of presidiums) of transport-related committees, councils, and boards is analysed. The study is aimed at the local level, since municipal transport policy decisions include areas with clear differences between masculinity and femininity norms. The mapping of representation reveals, in line with other studies, that women are underrepresented in the most leading position (as chairperson of the City Board 31-37%), and that presidiums of transport-related committees, especially, are highly dominated by men (72-74%) with no clear positive trend in female representation identified over the studied years. The result suggests that transport-related decisions are disproportionally shaped by men as well as masculine norms, with implications for the transition towards transport sustainability.
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| 13. |
- Hiselius, Lena Winslott, et al.
(författare)
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Investigating the Link between Transport Sustainability and the Representation of Women in Swedish Local Committees
- 2019
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 11:17
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Tidskriftsartikel (refereegranskat)abstract
- There are large discrepancies in the transport sector along gender lines in travel patterns and means of transportation used, but also in attitudes and norms among citizens, planners and decision-makers, with women generally more positive towards measures involving the lowering CO2 emissions. At the same time, the number of women involved in transport-related decisions is low. This is a problem for gender equality but possibly also for sustainability. A careful review of previous studies indicated a lack of analyses on the subject based on quantitative data at the local level. We investigated a possible link between women’s presence in local policymaking and more sustainable transport policies, and whether it is possible to capture such an effect. The main contribution of this paper is a methodological approach in which, besides generating unique data on representation in municipalities (confirming men’s dominance, specifically in transport policymaking), possibilities for quantitatively measuring gender and the level of sustainability in transport planning are discussed and tested. Challenges in collecting relevant data and analyzing possible covariances in the data set are discussed and presented as well as suggestions for further investigations into the possible link between gender and sustainable transport performance.
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| 14. |
- Jonsson, Christina E., et al.
(författare)
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High-resolution diatom delta O-18 records, from the last 150 years, reflecting changes in amount of winter precipitation in two sub-Arctic high-altitude lakes in the Swedish Scandes
- 2010
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 25:6, s. 918-930
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Tidskriftsartikel (refereegranskat)abstract
- Waters from high-altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high-altitude lakes have lake water isotopic compositions (delta O-18(lake)) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water delta O-18. Here we compare two high-resolution delta O-18(diatom) records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900-1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in delta O-18(diatom) as decreasing trends. Lowest delta O-18(diatom) values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the delta O-18(diatom) signal in these sub-Arctic high-altitude lakes with short residence times has been changes in amount of winter precipitation and that delta O-18(diatom) derived from high-altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy.
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| 15. |
- Jonsson, Christina E, et al.
(författare)
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High resolution diatom δ18O records from two sub-Arctic high altitude lakes in the Swedish Scandes
- 2010
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 25:6, s. 918-930
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Tidskriftsartikel (refereegranskat)abstract
- Waters from high-altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high-altitude lakes have lake water isotopic compositions (δ18Olake) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water δ18O. Here we compare two high-resolution δ18Odiatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900–1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ18Odiatom as decreasing trends. Lowest δ18Odiatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the δ18Odiatom signal in these sub-Arctic high-altitude lakes with short residence times has been changes in amount of winter precipitation and that δ18Odiatom derived from high-altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy. Copyright © 2010 John Wiley & Sons, Ltd.
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| 16. |
- Jonsson, C. E., et al.
(författare)
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Reconstructing past atmosperic circulation changes using oxygen isotopes in lake sediments from Sweden
- 2010
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 6:1, s. 49-62
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Tidskriftsartikel (refereegranskat)abstract
- Here we use lake sediment studies from Sweden to illustrate how Holocene-aged oxygen isotope records from lakes located in different hydrological settings, can provide information about climate change. In particular changes in precipitation, atmospheric circulation and water balance. We highlight the importance of understanding the present lake hydrology, and the relationship between climate variables and the oxygen isotopic composition of precipitation (d18Op)and lake waters (d18Olakewater) for interpretation of the oxygen isotopic record from the sediments (d18O). Both precipitation reconstructions from northern Sweden and water balance reconstructions from south and central Sweden show that the atmospheric circulation changed from zonal to a more meridional airflow over the Holocene. Superimposed on this Holocene trend are δ18Op minima resembling intervals of the negative phase of the North Atlantic Oscillation (NAO), thus suggesting that the climate of Northern Europe is strongly influenced by atmospheric and oceanic circulation changes over the North Atlantic.
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| 17. |
- Jonsson, Christina E., et al.
(författare)
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Stable oxygen and hydrogen isotopes in sub-Arctic lake wateras from northern Sweden
- 2009
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 376:1-2, s. 143-151
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Tidskriftsartikel (refereegranskat)abstract
- Lakes in sub-Arctic regions have the potential of retaining many different aspects of water isotope composition in their sediments which can be used for palaeoclimate reconstruction. It is therefore important to understand the modern isotope hydrology of these lakes. Here we discuss the significance of variations in water isotope composition of a series of lakes located in north-west Swedish Lapland. Climate in this region is forced by changes in the North Atlantic which renders it an interesting area for climate reconstructions. We compare δ18Olake and δ2Hlake collected between 2001 and 2006 and show that the lakes in this sub-Arctic region are currently mainly recharged by shallow groundwater and precipitation which undergoes little subsequent evaporation, and that the d18O and δ2H composition of input to the majority of the lakes varies on a seasonal basis between winter precipitation (and spring thaw) and summer precipitation. Seasonal variations in the isotopic composition of the lake waters are larger in lakes with short residence times (<6 months), which react faster to seasonal changes in the precipitation, compared to lakes with longer residence times (>6 months), which retain an isotopic signal closer to that of annual mean precipitation. Lake waters also show a range of isotope values between sites due to catchment elevation and timing of snow melt. The lake water data collected in this study was supported by isotope data from lake waters, streams and ground waters from1995 to 2000 reported in other studies.
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| 18. |
- Kronsell, Annica, 1959, et al.
(författare)
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Critical masculine and feminine norms in sustainable municipal transport policies and planning
- 2023
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Ingår i: Journal of Environmental Policy & Planning. - 1523-908X. ; 25:6, s. 663-675
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Tidskriftsartikel (refereegranskat)abstract
- Transport planning has historically been dominated by masculinity norms with minimal attention to sustainability, but these norms are challenged. Our analytical framework explores municipal solutions to sustainable transport that go beyond traditional norms and advances knowledge on how gendered sustainability norms are articulated in municipal transport policies and planning documents. The article investigates whether masculine and feminine norms on sustainability affect transport planning and if they are concretely expressed in transport solutions in planning and policy documents in Swedish municipalities, considered high achievers in sustainable transport. The article also observes gender representation and political affiliation related to gender sustainability norms. Our results show that all municipal committees that handle transport planning adhere to masculine and feminine sustainability norms but that there are significant differences in the content of the policies. Our results do not verify a relation between norms and the representation of men and women in the transport committees, we find evidence of divergences between masculine and feminine norms in relation to political ideas.
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| 19. |
- Lagergren, Fredrik, et al.
(författare)
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Kilometre-scale simulations over Fennoscandia reveal a large loss of tundra due to climate warming
- 2024
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Ingår i: Biogeosciences. - 1726-4170 .- 1726-4189. ; 21:5, s. 1093-1116
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Tidskriftsartikel (refereegranskat)abstract
- The Fennoscandian boreal and mountain regions harbour a wide range of vegetation types, from boreal forest to high alpine tundra and barren soils. The area is facing a rise in air temperature above the global average and changes in temperature and precipitation patterns. This is expected to alter the Fennoscandian vegetation composition and change the conditions for areal land use such as forestry, tourism and reindeer husbandry. In this study we used a unique high-resolution (3 km) climate scenario with considerable warming resulting from strongly increasing carbon dioxide emissions to investigate how climate change can alter the vegetation composition, biodiversity and availability of suitable reindeer forage. Using a dynamical vegetation model, including a new implementation of potential reindeer grazing, resulted in simulated vegetation maps of unprecedented high resolution for such a long time period and spatial extent. The results were evaluated at the local scale using vegetation inventories and for the whole area against satellite-based vegetation maps. A deeper analysis of vegetation shifts related to statistics of threatened species was performed in six “hotspot” areas containing records of rare and threatened species. In this high-emission scenario, the simulations show dramatic shifts in the vegetation composition, accelerating at the end of the century. Alarmingly, the results suggest the southern mountain alpine region in Sweden will be completely covered by forests at the end of the 21st century, making preservation of many rare and threatened species impossible. In the northern alpine regions, most vegetation types will persist but shift to higher elevations with reduced areal extent, endangering vulnerable species. Simulated potential for reindeer grazing indicates latitudinal differences, with higher potential in the south in the current climate. In the future these differences will diminish, as the potentials will increase in the north, especially for the summer grazing grounds. These combined results suggest significant shifts in vegetation composition over the present century for this scenario, with large implications for nature conservation, reindeer husbandry and forestry.
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| 20. |
- Leder, Lena, et al.
(författare)
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Effects of a healthy Nordic diet on gene expression changes in peripheral blood mononuclear cells in response to an oral glucose tolerance test in subjects with metabolic syndrome : A SYSDIET sub-study
- 2016
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Ingår i: Genes & Nutrition. - : Springer Science and Business Media LLC. - 1555-8932 .- 1865-3499. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diet has a great impact on the risk of developing features of metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM), and cardiovascular diseases (CVD). We evaluated whether a long-term healthy Nordic diet (ND) can modify the expression of inflammation and lipid metabolism-related genes in peripheral blood mononuclear cells (PBMCs) during a 2-h oral glucose tolerance test (OGTT) in individuals with MetS. Methods: A Nordic multicenter randomized dietary study included subjects (n = 213) with MetS, randomized to a ND group or a control diet (CD) group applying an isocaloric study protocol. In this sub-study, we included subjects (n = 89) from three Nordic centers: Kuopio (n =26), Lund (n = 30), and Oulu (n = 33) with a maximum weight change of ±4 kg, high-sensitivity C-reactive protein concentration ≤10 mg L-1, and baseline body mass index -2. PBMCs were isolated, and the mRNA gene expression analysis was measured by quantitative real-time polymerase chain reaction (qPCR). We analyzed the mRNA expression changes of 44 genes before and after a 2hOGTT at the beginning and the end of the intervention. Results: The healthy ND significantly down-regulated the expression of toll-like receptor 4 (TLR4), interleukin 18 (IL18), and thrombospondin receptor (CD36) mRNA transcripts and significantly up-regulated the expression of peroxisome proliferator-activated receptor delta (PPARD) mRNA transcript after the 2hOGTT compared to the CD. Conclusions: A healthy ND is able to modify the gene expression in PBMCs after a 2hOGTT. However, more studies are needed to clarify the biological and clinical relevance of these findings.
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| 21. |
- Lumetzberger, M., et al.
(författare)
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Predicting the fate of chlorinated aliphatics by hydrogeological modelling and DCIP data - Färgaren case study
- 2019
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Konferensbidrag (refereegranskat)abstract
- We present a local flow model approach for the transport and the decay of a roughly 50 year old perchloroethylene contamination at a former dry cleaning facility at Kv. Färgaren in Kristianstad that sits above the largest aquifer in Sweden. The study demonstrates an efficient workflow integrating ERT for conceptualising and calibrating a three dimensional transient, multi aquifer groundwater transport problem with a sequential first-order decay contamination where only limited sample data is available for calibration - i.e. non-ideal, real world conditions. The 3D hydraulic model geometry is based on information from ERT data. It was possible to map resistivity signatures correlated with boreholes to geological features with a high degree of accuracy. On the Färgaren site itself, a 3D IP inversion model displayed some IP effects that correlated with historical perchloroethylene source terms. The simulations provide new information regarding the vulnerability of a critical groundwater resource, filling in knowledge gaps left by traditional sampling methods. It is concluded that there is potential for long term contamination of the regional sandstone aquifer, and that the plume front may already have reached its upper layers.
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| 22. |
- Maier, Kathrin, et al.
(författare)
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Direct photogrammetry with multispectral imagery for UAV-based snow depth estimation
- 2022
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Ingår i: ISPRS journal of photogrammetry and remote sensing (Print). - : Elsevier BV. - 0924-2716 .- 1872-8235. ; 186, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- More accurate snow quality predictions are needed to economically and socially support communities in a changing Arctic environment. This contrasts with the current availability of affordable and efficient snow monitoring methods. In this study, a novel approach is presented to determine spatial snow depth distribution in challenging alpine terrain that was tested during a field campaign performed in the Tarfala valley, Kebnekaise mountains, northern Sweden, in April 2019. The combination of a multispectral camera and an Unmanned Aerial Vehicle (UAV) was used to derive three-dimensional (3D) snow surface models via Structure from Motion (SfM) with direct georeferencing. The main advantage over conventional photogrammetric surveys is the utilization of accurate Real-Time Kinematic (RTK) positioning which enables direct georeferencing of the images, and therefore eliminates the need for ground control points. The proposed method is capable of producing high -resolution 3D snow-covered surface models (<7 cm/pixel) of alpine areas up to eight hectares in a fast, reli-able and affordable way. The test sites' average snow depth was 160 cm with an average standard deviation of 78 cm. The overall Root-Mean-Square Errors (RMSE) of the snow depth range from 11.52 cm for data acquired in ideal surveying conditions to 41.03 cm in aggravated light and wind conditions. Results of this study suggest that the red components in the electromagnetic spectrum, i.e., the red, red edge, and near-infrared (NIR) band, contain the majority of information used in photogrammetric processing. The experiments highlighted a sig-nificant influence of the multi-spectral imagery on the quality of the final snow depth estimation as well as a strong potential to reduce processing times and computational resources by limiting the dimensionality of the imagery through the application of a Principal Component Analysis (PCA) before the photogrammetric 3D reconstruction. The proposed method is part of closing the scale gap between discrete point measurements and regional-scale remote sensing and complements large-scale remote sensing data and snow model output with an adequate validation source.
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| 23. |
- Meister, Philip, et al.
(författare)
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A global compilation of diatom silica oxygen isotope records from lake sediment - trends and implications for climate reconstruction
- 2024
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Ingår i: Climate of the Past. - 1814-9324. ; 20:2, s. 363-392
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen isotopes in biogenic silica (δ18OBSi) from lake sediments allow for quantitative reconstruction of past hydroclimate and proxy-model comparison in terrestrial environments. The signals of individual records have been attributed to different factors, such as air temperature (Tair), atmospheric circulation patterns, hydrological changes, and lake evaporation. While every lake has its own local set of drivers of δ18O variability, here we explore the extent to which regional or even global signals emerge from a series of paleoenvironmental records. This study provides a comprehensive compilation and combined statistical evaluation of the existing lake sediment δ18OBSi records, largely missing in other summary publications (i.e. PAGES network). For this purpose, we have identified and compiled 71 down-core records published to date and complemented these datasets with additional lake basin parameters (e.g. lake water residence time and catchment size) to best characterize the signal properties. Records feature widely different temporal coverage and resolution, ranging from decadal-scale records covering the past 150 years to records with multi-millennial-scale resolution spanning glacial-interglacial cycles. The best coverage in number of records (NCombining double low line37) and data points (NCombining double low line2112) is available for Northern Hemispheric (NH) extratropical regions throughout the Holocene (roughly corresponding to Marine Isotope Stage 1; MIS 1). To address the different variabilities and temporal offsets, records were brought to a common temporal resolution by binning and subsequently filtered for hydrologically open lakes with lake water residence times <100 years. For mid- to high-latitude (>45°N) lakes, we find common δ18OBSi patterns among the lake records during both the Holocene and Common Era (CE). These include maxima and minima corresponding to known climate episodes, such as the Holocene Thermal Maximum (HTM), Neoglacial Cooling, Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). These patterns are in line with long-term air temperature changes supported by previously published climate reconstructions from other archives, as well as Holocene summer insolation changes. In conclusion, oxygen isotope records from NH extratropical lake sediments feature a common climate signal at centennial (for CE) and millennial (for Holocene) timescales despite stemming from different lakes in different geographic locations and hence constitute a valuable proxy for past climate reconstructions.
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| 24. |
- Meth, Elisa, et al.
(författare)
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Association of Daily Eating Duration and Day-To-Day Variability in the Timing of Eating With Fatal Cancer Risk in Older Men
- 2022
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Ingår i: Frontiers in Nutrition. - : Frontiers Media S.A.. - 2296-861X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Meal timing has significant effects on health. However, whether meal timing is associated with the risk of developing and dying of cancer is not well-researched in humans. In the present study, we used data from 941 community-dwelling men aged 71 years who participated in the Uppsala Longitudinal Study of Adult Men to examine the association of meal timing with cancer morbidity and fatal cancer. The following meal timing variables were derived from 7-day food diaries: (i) daily eating duration, i.e., the time between the first and last eating episode of an arbitrary day; (ii) the calorically weighted midpoint of the daily eating interval, a proxy of when the eating window typically occurs during an arbitrary day; and (iii) the day-to-day variability in the timing of eating. We also assessed the reported daily energy intake reliability using the Goldberg method. During a mean observational period of 13.4 years, 277 men (29.4%) were diagnosed with cancer. Furthermore, 191 men (20%) died from cancer during 14.7 years of follow-up. As shown by Cox regression adjusted for potential confounders (e.g., smoking status and daily energy intake), men with reliable dietary reports whose daily eating intervals were on average 13 h long had a 2.3-fold greater fatal cancer risk than men whose daily eating windows were on average about 11 h long. We also found that men with an average day-to-day variability in the timing of eating of 48 to 74 min had a 2- to 2.2-fold higher fatal cancer risk than those with the lowest average day-to-day variability in the timing of eating (i.e., 23 min). No clear associations were found in men with inadequate dietary reports, emphasizing the need to consider the reliability of dietary records in nutritional epidemiology. To fully unlock its potential, studies are needed to test whether recommendations to time-restrict the 24-h eating interval and reduce day-to-day variability in the timing of eating can meaningfully alter the risk of death due to cancer.
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| 25. |
- Myhrstad, Mari C. W., et al.
(författare)
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Healthy Nordic Diet Modulates the Expression of Genes Related to Mitochondrial Function and Immune Response in Peripheral Blood Mononuclear Cells from Subjects with Metabolic Syndrome-A SYSDIET Sub-Study
- 2019
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Ingår i: Molecular Nutrition & Food Research. - : John Wiley & Sons. - 1613-4125 .- 1613-4133. ; 63:13
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Tidskriftsartikel (refereegranskat)abstract
- Scope To explore the effect of a healthy Nordic diet on the global transcriptome profile in peripheral blood mononuclear cells (PBMCs) of subjects with metabolic syndrome. Methods and results Subjects with metabolic syndrome undergo a 18/24 week randomized intervention study comparing an isocaloric healthy Nordic diet with an average habitual Nordic diet served as control (SYSDIET study). Altogether, 68 participants are included. PBMCs are obtained before and after intervention and total RNA is subjected to global transcriptome analysis. 1302 probe sets are differentially expressed between the diet groups (p-value < 0.05). Twenty-five of these are significantly regulated (FDR q-value < 0.25) and are mainly involved in mitochondrial function, cell growth, and cell adhesion. The list of 1302 regulated probe sets is subjected to functional analyses. Pathways and processes involved in the mitochondrial electron transport chain, immune response, and cell cycle are downregulated in the healthy Nordic diet group. In addition, gene transcripts with common motifs for 42 transcription factors, including NFR1, NFR2, and NF-kappa B, are downregulated in the healthy Nordic diet group. Conclusion These results suggest that benefits of a healthy diet may be mediated by improved mitochondrial function and reduced inflammation.
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