| 1. |
- Björck, Svante, et al.
(författare)
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A South Atlantic island record uncovers shifts in westerlies and hydroclimate during the last glacial
- 2019
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 15:6, s. 1939-1958
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Tidskriftsartikel (refereegranskat)abstract
- Changes in the latitudinal position and strength of the Southern Hemisphere westerlies (SHW) are thought to be tightly coupled to important climate processes, such as cross-equatorial heat fluxes, Atlantic Meridional Overturning Circulation (AMOC), the bipolar seesaw, Southern Ocean ventilation and atmospheric CO2 levels. However, many uncertainties regarding magnitude, direction, and causes and effects of past SHW shifts still exist due to lack of suitable sites and scarcity of information on SHW dynamics, especially from the last glacial. Here we present a detailed hydroclimate multiproxy record from a 36.4-18.6 kyr old lake sediment sequence on Nightingale Island (NI). It is strategically located at 37ĝF S in the central South Atlantic (SA) within the SHW belt and situated just north of the marine Subtropical Front (SF). This has enabled us to assess hydroclimate changes and their link to the regional climate development as well as to large-scale climate events in polar ice cores. The NI record exhibits a continuous impact of the SHW, recording shifts in both position and strength, and between 36 and 31 ka the westerlies show high latitudinal and strength-wise variability possibly linked to the bipolar seesaw. This was followed by 4 kyr of slightly falling temperatures, decreasing humidity and fairly southerly westerlies. After 27 ka temperatures decreased 3-4 ĝC, marking the largest hydroclimate change with drier conditions and a variable SHW position. We note that periods with more intense and southerly-positioned SHW seem to be related to periods of increased CO2 outgassing from the ocean, while changes in the cross-equatorial gradient during large northern temperature changes appear as the driving mechanism for the SHW shifts. Together with coeval shifts of the South Pacific westerlies, our results show that most of the Southern Hemisphere experienced simultaneous atmospheric circulation changes during the latter part of the last glacial. Finally we can conclude that multiproxy lake records from oceanic islands have the potential to record atmospheric variability coupled to large-scale climate shifts over vast oceanic areas..
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| 2. |
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| 3. |
- Enkirch, Theresa, et al.
(författare)
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Hepatitis A outbreak linked to imported frozen strawberries by sequencing, Sweden and Austria, June to September 2018
- 2018
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Ingår i: Eurosurveillance. - : European Centre for Disease Prevention and Control. - 1025-496X .- 1560-7917. ; 23:41
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Tidskriftsartikel (refereegranskat)abstract
- Between June-September 2018, 20 hepatitis A cases were notified in six counties in Sweden. Combined epidemiological and microbiological investigations identified imported frozen strawberries produced in Poland as the source of the outbreak. Sequence analysis confirmed the outbreak strain IB in the strawberries with 100 % identity and the respective batch was withdrawn. Sharing the sequence information internationally led to the identification of 14 additional cases in Austria, linked to strawberries from the same producer.
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| 4. |
- Hammarlund, Dan, et al.
(författare)
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Palaeolimnological and sedimentary responses to Holocene forest retreat in the Scandes Mountains, west-central Sweden
- 2004
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Ingår i: Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 14:6, s. 862-876
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Tidskriftsartikel (refereegranskat)abstract
- A suite of analyses was performed on sediments accumulated during the last 10 700 years in Lake Spaime, a small, hydrologically open water body in the modern alpine tundra zone of the Scandes Mountains, west-central Sweden. The study aimed to evaluate (1) the nature of climate changes that forced the late-Holocene lowering of altitudinal tree limit in the region, the timing of which is known from prior studies based on radiocarbon dating of subfossil wood, and (2) the impact of these vegetational changes on an aquatic ecosystem. Arboreal pollen and plant macrofossil data confirm the persistence of trees in the lake catchment at least from c. 9700 cal. BP until c. 3700 cal. BP. Although growing-season temperature is commonly believed to be the dominant factor driving boreal forest tree-limit variations in the region, a chironomid-based reconstruction of mean July air temperature suggests that local deforestation during the late Holocene was not accompanied by a significant cooling. The tree-limit retreat was more likely caused by increasing effective moisture and declining length of the growing season. The ecohydrological response of Lake Spaime to this combination of climate and vegetational changes included a decline in primary productivity, as indicated by an abrupt decrease in sediment organic matter content, while associated increases in organic delta(13)C, delta(15)N and C/N point to diminished fluxes and altered balance of catchment-derived nutrients following deforestation. The decline in aquatic productivity is also marked by a distinct change in the mineral magnetic properties, from a high magnetic concentration assemblage dominated by fine-grained magnetite of biogenic origin to one dominated by background levels of coarse-grained detrital magnetite.
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| 5. |
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| 6. |
- Hansson, Anton, et al.
(författare)
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Shoreline displacement and human resource utilization in the southern Baltic Basin coastal zone during the early Holocene: New insights from a submerged Mesolithic landscape in south-eastern Sweden
- 2018
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 28:5, s. 721-737
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Tidskriftsartikel (refereegranskat)abstract
- Along parts of the Hanö Bay coast in south-eastern Sweden, remains of a submerged landscape can be found down to depths of almost 25 m b.s.l. The coastal landscape was formed during two periods of lowered water levels in the Baltic Basin: the Yoldia Sea and the Initial Littorina Sea stages. In order to reconstruct the local environment and shoreline displacement during the Yoldia Sea and Ancylus Lake stages, sediment sequences were obtained at 4.5, 17.5 and 18.7 m b.s.l. Detailed bathymetric mapping was based on multi-beam echo-sounding while surveillance and sampling of tree remains and archaeological findings were performed through diving. The Yoldia Sea low-stand reached its minimum level at 24–25 m b.s.l. just before 10,800 cal. BP. During the subsequent Ancylus transgression, a slow-flowing river passed through the area, accumulating thick deposits of fine-grained organic sediments in lagoonal basins. The river was surrounded by open woodland dominated by pine. Based on successive flooding of rooted tree stumps, the transgression rate was estimated at 4 cm·yr−1, until the Ancylus high-stand was reached at 5 m b.s.l. at 10,400–10,300 cal. BP. Findings of worked aurochs and beaver bones provide evidence of human presence in the landscape and show the importance of terrestrial resources for their subsistence. These integrated palaeoecological and archaeological investigations demonstrate the importance of submerged landscapes with well-preserved sediment, wood and bone material for our understanding of southern Baltic coastal landscapes and their inhabitants during the Early Mesolithic.
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| 7. |
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| 8. |
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| 9. |
- Holmgren, Sofia, et al.
(författare)
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Cytokine mRNA expression in bronchoalveolar lavage cells during Dictyocaulus viviparus infection in calves
- 2014
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Ingår i: Parasite Immunology. - : Wiley. - 0141-9838 .- 1365-3024. ; 36, s. 78-86
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to monitor local cytokine responses to Dictyocaulus viviparus in calves during primary infection and re-infection. Bronchoalveolar lavage fluid (BALF) was collected weekly from experimentally infected calves and interleukin-2 (IL-2), IL-4, IL-5, IL-10 and IFN- mRNA expression was quantified in BALF cells. The major finding was a prominent transient increase in IL-4 mRNA expression, compared with that of uninfected calves, observed in BALF cells collected 2-3weeks post-primary D.viviparus infection. At 2weeks post-infection, macroscopic worms were also first observed in BALF. Calves re-infected after 10weeks were partially immune which was evident at slaughter 5weeks post-infection as a lower worm burden than in previously naive calves infected at the same time. IL-4 mRNA expression in BALF cells 2weeks post-re-infection was increased compared with that of uninfected animals but not as high as that of primarily infected calves. BALF cell expression of the other cytokines tested for was not as clearly effected by the D.viviparus infection. It seems likely that the strong IL-4 response observed during primary infection reflects an innate response to the worms that may initiate an ensuing Th2 response, which confers protective immunity.
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| 10. |
- Holmgren, Sofia, et al.
(författare)
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Holocene environmental changes on Nightingale Island, South Atlantic, based on diatom floristic changes in an infilled pond
- 2013
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 1872-616X .- 0031-0182. ; 378, s. 45-51
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Tidskriftsartikel (refereegranskat)abstract
- A Holocene diatom stratigraphy of 2nd Pond, a small, filled pond on Nightingale Island (37 degrees 25 S, 12 degrees 29 W) was analyzed and interpreted to infer paleolimnological changes on Tristan da Cunha, South Atlantic. The diatom assemblage of 2nd Pond has the character of an acidic, oligotrophic wetland and the diatom record suggests that 2nd Pond most likely has been a bog/wetland throughout most of the Holocene. The-flora is largely dominated by Pinnularia viridis, a species typically found in peat bogs. The flora also includes benthic and epiphytic Gomphonema sp, Achnanthes saxonica, Frustulia cf. rhomboides, Staurosira venter as well as Pinnularia cf. divergens var. decrescens and Eunotia paludosa var. paludosa. Peaks of aerophytic diatom (i.e. mostly Diadesmis spp. and Luticola spp.) abundances and concentrations correspond to increased magnetic susceptibility and slightly higher C/N ratios and are interpreted to be the result of increased catchment erosion due to precipitation and following increased in-wash of terrestrial diatoms. The diatom record suggests dry conditions in the early Holocene, followed by recurrent periods of increased precipitation in the region at 8600-5600 cal a BP and at 2200-1700 cal a BP. The main causes for these hydrological changes are probably changes in intensity and/or position of the Southern hemisphere west wind belt. (C) 2013 Elsevier B.V. All rights reserved.
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| 11. |
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| 12. |
- Holmgren, Sofia, et al.
(författare)
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Late Holocene environmental history on Tristan da Cunha, South Atlantic, based on diatom floristic changes and geochemistry in sediments of a volcanic crater lake
- 2012
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Ingår i: Journal of Paleolimnology. - : Springer Science and Business Media LLC. - 0921-2728 .- 1573-0417. ; 47:2, s. 221-232
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Tidskriftsartikel (refereegranskat)abstract
- A late Holocene diatom stratigraphy of Bottom Pond (37050S, 12 70W) was studied and interpreted to infer paleolimnological and climate changes on Tristan da Cunha, South Atlantic. The diatom flora of Bottom Pond is dominated by meroplanktonic Aulacoseira alpigena and A. distans and a benthic/epiphytic flora including Achnanthes spp., Naviculadicta spp., Eunotia taxa and Frustulia rhomboides. The flora also includes an important terrestrial and aerophytic component, consisting of several Diadesmis spp., Navicula lapidosa, Nitzschia terrestris and some Pinnularia spp., at times dominating the flora. Peaks of high terrestrial diatom abundances and low abundances and concentrations of Aulacoseira spp., correspond to periods of increased magnetic susceptibility and are interpreted to be the result of increased catchment erosion and/or precipitation leading to enhanced in-wash of species living in the soils around the lake. The diatom record of Bottom Pond most likely registers both local responses to increased erosion in the catchment as well as climatic change of a more regional character. Comparisons with the geochemical record in 2nd Pond on Nightingale Island show a correspondence between the two data sets at 2,000–1,750 cal yrs BP, most likely evidence of increased precipitation in the Tristan da Cunha region. The Tristan da Cunha archipelago is situated at the northern limit of the Southern hemisphere west wind belt and stronger and/ or a northward shift of the westerlies, are probably the main causes of the precipitation changes.
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| 13. |
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| 14. |
- Holmgren, Sofia, 1975, et al.
(författare)
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The Holocene-Anthropocene transition in lakes of western Spitsbergen, Svalbard (Norwegian High Arctic): climate change and nitrogen deposition
- 2010
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Ingår i: JOURNAL OF PALEOLIMNOLOGY. - : Springer Science and Business Media LLC. - 0921-2728 .- 1573-0417. ; 43:2, s. 393-412
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Tidskriftsartikel (refereegranskat)abstract
- Lake sediments from four small lakes on western Spitsbergen (Svalbard Archipelago, Norwegian High Arctic) preserve biostratigraphic and isotopic evidence for a complex suite of twentieth century environmental changes. At Lake Skardtjørna and Lake Tjørnskardet on Nordenskio¨ldkysten, there is a marked diatom floristic change coupled to increased diatom concentrations beginning around 1920. At Lake Istjørna and Lake Istjørnelva, 25 km southwest of Longyearbyen, both diatom total valve and chrysophyte stomatocyst concentrations have increased dramatically since the beginning of the 1900s. The early twentieth century changes are probably related to climate warming after the Little Ice Age. However, the most pronounced changes in diatom assemblages seem to have occurred in the last few decades. At the same time, nitrogen stable isotopes in sediment organic matter in two of the lakes became progressively depleted by*2%, which is consistent with diffuse atmospheric inputs from anthropogenic sources and attendant fertilization. These data suggest that climate change and nitrogen deposition may be acting together in driving these lakes towards new ecological states that are unique in the context of the Holocene.
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| 15. |
- Holmgren Troy, Maria, 1962-, et al.
(författare)
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Introduction : Gothic and Uncanny Explorations
- 2017
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Ingår i: Edda. Nordisk tidsskrift for litteraturforskning. - : Universitetsforlaget. - 0013-0818 .- 1500-1989. ; 104:2, s. 108-114
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Holmgren Troy, Maria, 1962-
(författare)
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Nordic Gothic
- 2020
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Bok (refereegranskat)abstract
- Nordic Gothic traces Gothic fiction in the Nordic region from its beginnings in the nineteenth century, with a main focus on the development of Gothic from the 1990s onwards in literature, film, TV and new media. The volume gives an overview of Nordic Gothic fiction in relation to transnational developments and provides a number of case studies and in-depth analyses of individual narratives. It creates an understanding of this under-researched cultural phenomenon by showing how the narratives make visible cultural anxieties haunting the Nordic countries, their welfare systems, identities and ideologies. Nordic Gothic examines how figures from Nordic folklore function as metaphorical expressions of Gothic themes and Nordic settings are explored from perspectives such as ecocriticism and postcolonialism. The book will be of interest to researchers and post- and- undergraduate students in various fields within the Humanities.
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| 17. |
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| 18. |
- Holtgrieve, Gordon W., et al.
(författare)
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A Coherent Signature of Anthropogenic Nitrogen Deposition to Remote Watersheds of the Northern Hemisphere
- 2011
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 334:6062, s. 1545-1548
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Tidskriftsartikel (refereegranskat)abstract
- Humans have more than doubled the amount of reactive nitrogen (Nr) added to the biosphere, yet most of what is known about its accumulation and ecological effects is derived from studies of heavily populated regions. Nitrogen (N) stable isotope ratios (N-15:N-14) in dated sediments from 25 remote Northern Hemisphere lakes show a coherent signal of an isotopically distinct source of N to ecosystems beginning in 1895 +/- 10 years (+/- 1 standard deviation). Initial shifts in N isotope composition recorded in lake sediments coincide with anthropogenic CO2 emissions but accelerate with widespread industrial Nr production during the past half century. Although current atmospheric Nr deposition rates in remote regions are relatively low, anthropogenic N has probably influenced watershed N budgets across the Northern Hemisphere for over a century.
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| 19. |
- Höglund, Johan, 1967-, et al.
(författare)
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Introduction
- 2020
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Ingår i: Nordic Gothic. - Manchester : Manchester University Press. - 9781526126436 ; , s. 1-10
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Bokkapitel (refereegranskat)abstract
- This introductory chapter describes how, in the Nordic countries, Gothic fiction has become increasingly pervasive and popular in the past few decades and invaded all cultural registers – popular, highbrow, children’s and young adult fiction.
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| 20. |
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| 21. |
- Klugman, Sofia, et al.
(författare)
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Energy Integration of Domsjö Biorefinery Cluster - Summary
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Within the Domsjö Biorefinery cluster in Örnsköldsvik, all the industries are cooperating regarding energy. The cluster consists of one wood pulp production facility, two bio-chemical facilities and one energy facility. In this study, we have analysed how efficient the steam is used within the industries. Are steam of right pressure and temperature used for the right purposes? To what extent could steam be replaced by district heating? And, how big is the potential to use simultaneous heat and cold demand for energy integration? The method for energy analysis was “pinch analysis”. It is found that steam of 7 bar(g) and 170 °C is used to supply a major part of the heat demand, sometimes even heat demands of low temperatures. Such demands would be more efficient to supply by district heating. Alternatively, a new utility with temperatures 40/120 °C could be introduced, either within the total site, or only within the biggest of the industries. The practical heat recovery potential is about 15 MW for the total site, and about 10 MW at the biggest of the industries. For all alternatives, steam capacity is released, which for example could be used for increased industrial production without investments in new steam boilers. Alternatively, the released capacity could be used to completely (or partially) offset the steam requirements of a new process plant at the Domsjö site.
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| 22. |
- Kumar, Jagarlamudi Kiran, et al.
(författare)
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AroCell TK 210 ELISA for determination of TK1 protein : age-related reference ranges and comparison with other TK1 assays
- 2020
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Ingår i: BioTechniques. - : FUTURE SCI LTD. - 0736-6205 .- 1940-9818. ; 68:6, s. 335-342
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Tidskriftsartikel (refereegranskat)abstract
- Thymidine kinase 1 (TK1) is an enzyme involved in DNA precursor synthesis that has been used as a biomarker for prognosis and monitoring of different malignancies. In this study, we compared two immunoassays for measuring TK1 protein concentrations: the TK 210 ELISA (AroCell AB) and TK1 ELISA from Abcam. Overall, the TK 210 ELISA showed higher sensitivity than the Abcam TK1 ELISA for differentiating hematological malignancies (sensitivity of 0.77 vs 0.45) as well as for distinguishing sera of patients with solid tumors from those of apparently healthy individuals (0.61 vs 0.20). There was no significant difference in the TK1 protein levels determined with the TK 210 ELISA between different age groups from apparently healthy individuals. These results strongly indicate that the AroCell TK 210 ELISA is accurate and sensitive enough to be a valuable tool in cancer management. METHOD SUMMARY Thymidine kinase 1 (TK1) is an enzyme that leaks from S phase cells as a result of high cell turnover. Commercially available TK activity assays have certain limitations; to overcome these, we developed a dual monoclonal antibody-based ELISA, the AroCell TK 210 ELISA, which is commercially available. The ELISA includes a preincubation procedure with a special buffer that reduces high molecular weight complexes of serum TK1 and exposes the TK1 epitope to facilitate antibody binding. This provides a robust and convenient assay for the determination of TK1 protein concentrations in sera from patients with different malignancies.
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| 23. |
- Leffler, Yvonne, 1959, et al.
(författare)
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Introduction
- 2020
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Ingår i: Nordic Gothic / Maria Holmgren Troy, Johan Höglund, Yvonne Leffler and Sofia Wijkmark.. - Manchester : Manchester University Press. - 9781526126436 ; , s. 1-11
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Lemdahl, Geoffrey, et al.
(författare)
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Eemian and Early Weichselian environments in southern Sweden: a multi-proxy study of till-covered organic deposits from the Småland peneplain.
- 2013
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 28:7, s. 705-719
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Tidskriftsartikel (refereegranskat)abstract
- Based on their luminescence and infinite radiocarbon ages, organic deposits beneath till at two sites on the Småland peneplain, southern Sweden (Nybygget and Stora Gäddevik), are concluded to have formed before the Middle Weichselian. Applied palaeoecological methods include analyses of pollen, diatoms, charcoal fragments, macroscopic remains of vascular plants and mosses, and insect remains. Pollen-stratigraphical correlations with previously studied interglacial/interstadial sites in southern Sweden, Denmark and northern Germany suggest that the peat at Nybygget dates from the Brørup interstadial or the final stage of the Eemian interglacial, whereas the lake sediments at Stora Gäddevik probably were emplaced during the middle Eemian. We conclude that the peat was formed in a wetland characterized by both wood swamp and open mire vegetation, and surrounded by semi-open woodlands dominated by pine, birch and hazel. The middle Eemian sequence at the Stora Gäddevik site provides evidence of a moderately nutrient-rich to nutrient-rich lake environment with relatively diverse aquatic vegetation. Regional vegetation, as reconstructed using the REVEALS model, was spruce woodland mixed with pine, alder and birch, but also included more open environments with hazel, oak, grasslands and sedge-dominated wetlands. Water shield (Brasenia schreberi), now extinct in Europe, was identified in the Eemian lake deposits, from both pollen and macroscopic remains.
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| 25. |
- Lindvall, Hanna, et al.
(författare)
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A Holocene peat record in the central South Atlantic: an archive of precipitation changes
- 2011
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Ingår i: GFF. - : Informa UK Limited. - 2000-0863 .- 1103-5897. ; 133:3-4, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- Peat deposits from the littoral part of the wetland 2nd Pond on Nightingale Island in the central South Atlantic have been analysed to investigate the Holocene climate development on the island and to test a hypothesis about regionally persistent humidity variations. A variety of proxies were analysed - total carbon and nitrogen, biogenic silica, diatoms, amount of organic matter, macrofossils and magnetic susceptibility - and together with the lithology they are interpreted as a record reflecting changes in humidity/precipitation. Early Holocene (10,000-8500 cal. BP) was possibly significantly drier than today, probably caused by a southerly displacement of the Southern Hemisphere Westerlies (SHW) during the Antarctic climate optimum. From 8500 cal. BP and onwards, the climate became generally more humid and surface run-off increased due to higher precipitation, possibly as an effect of increased influence from the SHW as it moved north. During this generally humid period, our data disclose a distinct pattern of recurrent centennial- to millennial-long events of increased precipitation and the results corroborate the only other study in the region with a similar humidity record. The events might represent large-scale climate oscillations in the Southern Hemisphere, such as latitudinal shifts of the SHW, but may also be related to changes in sea surface temperatures.
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