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Sökning: WFRF:(Filipsson Helena L.)

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1.
  • Charrieau, L. M., et al. (författare)
  • The effects of multiple stressors on the distribution of coastal benthic foraminifera: A case study from the Skagerrak-Baltic Sea region
  • 2018
  • Ingår i: Marine Micropaleontology. - : Elsevier. - 0377-8398. ; 139, s. 42-56
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal ecosystems are subjected to both large natural variability and increasing anthropogenic impact on environmental parameters such as changes in salinity, temperature, and pH. This study documents the distribution of living benthic foraminifera under the influence of multiple environmental stressors in the Skagerrak-Baltic Sea region. Sediment core tops were studied at five sites along a transect from the Skagerrak to the Baltic Sea, with strong environmental gradients, especially in terms of salinity, pH, calcium carbonate saturation and dissolved oxygen concentration in the bottom water and pore water. We found that living foraminiferal densities and species richness were higher at the Skagerrak station, where the general living conditions were relatively beneficial for Foraminifera, with higher salinity and Ωcalc in the water column and higher pH and oxygen concentration in the bottom and pore water. The most common species reported at each station reflect the differences in the environmental conditions between the stations. The dominant species were Cassidulina laevigata and Hyalinea balthica in the Skagerrak, Stainforthia fusiformis, Nonionella aff. stella and Nonionoides turgida in the Kattegat and N. aff. stella and Nonionellina labradorica in the Öresund. The most adverse conditions, such as low salinity, low Ωcalc, low dissolved oxygen concentrations and low pH, were noted at the Baltic Sea stations, where the calcareous tests of the dominant living taxa Ammonia spp. and Elphidium spp. were partially to completely dissolved, probably due to a combination of different stressors affecting the required energy for biomineralization. Even though Foraminifera are able to live in extremely varying environmental conditions, the present results suggest that the benthic coastal ecosystems in the studied region, which are apparently affected by an increase in the range of environmental variability, will probably be even more influenced by a future increase in anthropogenic impacts, including coastal ocean acidification and deoxygenation.
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2.
  • Kotthoff, U., et al. (författare)
  • Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)
  • 2017
  • Ingår i: ; 14, s. 5607-5632
  • Tidskriftsartikel (refereegranskat)abstract
    • Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past  ∼  8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until  ∼  7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish–marine conditions of the Littorina Sea stage (more saline and warmer) occurred within  ∼  200 years when the connection to the Kattegat became established after  ∼  7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from freshwater to marine conditions. Our study shows that particular caution has to be taken when applying and interpreting proxies in coastal environments and marginal seas, where water mass conditions can experience more rapid and larger changes than in open ocean settings. Approaches using a multitude of independent proxies may thus allow a more robust paleoenvironmental assessment.
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3.
  • Onnestam, Lisa, et al. (författare)
  • National Incidence and Prevalence of TSH-Secreting Pituitary Adenomas in Sweden.
  • 2013
  • Ingår i: Journal of Clinical Endocrinology and Metabolism. - : Oxford University Press. - 1945-7197 .- 0021-972X. ; 98:2, s. 626-635
  • Tidskriftsartikel (refereegranskat)abstract
    • Context:TSH-secreting pituitary adenomas (TSHomas) are rare. Epidemiological data are scant and there are no reports on national incidence.Objective:The objective of the study was to estimate the national Swedish incidence and prevalence of TSHomas.Design:This was an observational study.Setting:The study was conducted at tertiary referral centers.Patients:The Swedish Pituitary Registry and World Health Organization International Statistical Classification of Diseases and Related Health Problems coding at all university hospitals were used to identify patients diagnosed with TSHomas 1990-2010. The identified patients' medical records were studied until the latest follow-up [median 5.0 years (range < 1-20 years)].Main Outcome Measurements:Incidence, prevalence, demographics, tumor characteristics, treatment outcome, and thyroid hormone level at diagnosis were measured.Results:The age-standardized national incidence of 28 TSHoma patients was 0.15 per 1 million inhabitants per year, with an increasing incidence over time (0.05 per 1 million per year in 1990-1994 to 0.26 per 1 million per year in 2005-2009). The national prevalence in 2010 was 2.8 per 1 million inhabitants, in which 0.85 per 1 million had active disease. Most patients (n = 22) underwent pituitary surgery, 5 had radiotherapy, and 6 had somatostatin analogues. Eighteen patients were considered cured at the latest follow-up; 25% remained uncontrolled. Subjects treated for putative primary hyperthyroidism prior to diagnosis had TSH levels more than double those with intact thyroid at diagnosis (P = .013). The median time to diagnosis was longer for women than men (4 vs < 1 year, P = .026). More women than men were treated surgically (94.1% vs 54.5%, P = .022).Conclusion:This is the first estimate of a national incidence of TSHoma. Additional epidemiological studies are needed to compare these results with other geographical areas. This study suggests an increased incidence of TSHomas, in agreement with reports on other pituitary adenomas.
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4.
  • Hyttinen, O., et al. (författare)
  • Deglaciation dynamics of the Fennoscandian Ice Sheet in the Kattegat, the gateway between the North Sea and the Baltic Sea Basin
  • 2020
  • Ingår i: Boreas. - : John Wiley & Sons. - 0300-9483 .- 1502-3885.
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents an age–depth model based on an ultra-high-resolution, 80-m-thick sedimentary succession from a marine continental shelf basin, the Kattegat. This is an area of dynamic deglaciation of the Fennoscandian Ice Sheet during the Late Pleistocene. The Kattegat is also a transitional area between the saline North Sea and the brackish Baltic Sea. As such, it records general development of currents and exchange between these two systems. Data for the succession were provided through the Integrated Ocean Drilling Program Site M0060. The site indicates onset of deglaciation at c. 18 ka BP and relatively continuous sedimentation until 13 ka BP. At this point, sediments record a hiatus until c. 9–7 ka BP. The uppermost sedimentary unit contains redeposited material, but it is estimated to represent only the last c. 9–7 ka BP. The age–depth model is based on 17 select, radiocarbon-dated samples and is integrated with a set of physical and chemical proxies. The integrated records provide novel constraints on the timing of major palaeoenvironmental changes, such as the transition from glaciomarine proximal to glaciomarine distal and marine conditions, and their connections to known major events and processes in the region and the North Atlantic. Depositional evidence specifically documents connections between the Fennoscandian Ice Sheet behaviour and atmospheric and oceanic warming. Glacial retreat may have also depended on topographic factors such as changes in basin width and depth, linked to relative sea level changes and land uplift. The results indicate an early response of the Fennoscandian Ice Sheet to changing climate, and the ice sheet's possible influence on oceanic circulation during the Late Pleistocene deglaciation.
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5.
  • Ittermann, T., et al. (författare)
  • Standardized Map of Iodine Status in Europe
  • 2020
  • Ingår i: Thyroid. - 1050-7256.
  • Tidskriftsartikel (refereegranskat)abstract
    • Background:Knowledge about the population's iodine status is important, because it allows adjustment of iodine supply and prevention of iodine deficiency. The validity and comparability of iodine-related population studies can be improved by standardization, which was one of the goals of the EUthyroid project. The aim of this study was to establish the first standardized map of iodine status in Europe by using standardized urinary iodine concentration (UIC) data. Materials and Methods:We established a gold-standard laboratory in Helsinki measuring UIC by inductively coupled plasma mass spectrometry. A total of 40 studies from 23 European countries provided 75 urine samples covering the whole range of concentrations. Conversion formulas for UIC derived from the gold-standard values were established by linear regression models and were used to postharmonize the studies by standardizing the UIC data of the individual studies. Results:In comparison with the EUthyroid gold-standard, mean UIC measurements were higher in 11 laboratories and lower in 10 laboratories. The mean differences ranged from -36.6% to 49.5%. Of the 40 postharmonized studies providing data for the standardization, 16 were conducted in schoolchildren, 13 in adults, and 11 in pregnant women. Median standardized UIC was <100 mu g/L in 1 out of 16 (6.3%) studies in schoolchildren, while in adults 7 out of 13 (53.8%) studies had a median standardized UIC <100 mu g/L. Seven out of 11 (63.6%) studies in pregnant women revealed a median UIC Conclusions:We demonstrate that iodine deficiency is still present in Europe, using standardized data from a large number of studies. Adults and pregnant women, particularly, are at risk for iodine deficiency, which calls for action. For instance, a more uniform European legislation on iodine fortification is warranted to ensure that noniodized salt is replaced by iodized salt more often. In addition, further efforts should be put on harmonizing iodine-related studies and iodine measurements to improve the validity and comparability of results.
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6.
  • Jagers, Sverker C., 1967, et al. (författare)
  • Societal causes of, and responses to, ocean acidification.
  • 2019
  • Ingår i: Ambio. - : Springer. - 1654-7209 .- 0044-7447. ; 48:8, s. 816-830
  • Tidskriftsartikel (refereegranskat)abstract
    • Major climate and ecological changes affect the world's oceans leading to a number of responses including increasing water temperatures, changing weather patterns, shrinking ice-sheets, temperature-driven shifts in marine species ranges, biodiversity loss and bleaching of coral reefs. In addition, ocean pH is falling, a process known as ocean acidification (OA). The root cause of OA lies in human policies and behaviours driving society's dependence on fossil fuels, resulting in elevated CO2 concentrations in the atmosphere. In this review, we detail the state of knowledge of the causes of, and potential responses to, OA with particular focus on Swedish coastal seas. We also discuss present knowledge gaps and implementation needs.
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7.
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8.
  • McKay, C.L., et al. (författare)
  • A comparison of benthic foraminiferal Mn/Ca and sedimentary Mn/Al as proxies of relative bottom-water oxygenation in the low-latitude NE Atlantic upwelling system.
  • 2015
  • Ingår i: Biogeosciences. - : Copernicus Publications. - 1726-4170 .- 1726-4189. ; 12, s. 5415-5428
  • Tidskriftsartikel (refereegranskat)abstract
    • Trace element incorporation into foraminiferal shells (tests) is governed by physical and chemical conditions of the surrounding marine environment, and therefore foraminiferal geochemistry provides a means of palaeo-oceanographic reconstructions. With the availability of high-spatial-resolution instrumentation with high precision, foraminiferal geochemistry has become a major research topic over recent years. However, reconstructions of past bottom-water oxygenation using foraminiferal tests remain in their infancy. In this study we explore the potential of using Mn / Ca determined by secondary ion mass spectrometry (SIMS) as well as by flow-through inductively coupled plasma optical emission spectroscopy (FT-ICP-OES) in the benthic foraminiferal species Eubuliminella exilis as a proxy for recording changes in bottom-water oxygen conditions in the low-latitude NE Atlantic upwelling system. Furthermore, we compare the SIMS and FT-ICP-OES results with published Mn sediment bulk measurements from the same sediment core. This is the first time that benthic foraminiferal Mn / Ca is directly compared with Mn bulk measurements, which largely agree on the former oxygen conditions. Samples were selected to include different productivity regimes related to Marine Isotope Stage 3 (35–28 ka), the Last Glacial Maximum (28–19 ka), Heinrich Event 1 (18–15.5 ka), Bølling Allerød (15.5–13.5 ka) and the Younger Dryas (13.5–11.5 ka). Foraminiferal Mn / Ca determined by SIMS and FT-ICP-OES is comparable. Mn / Ca was higher during periods with high primary productivity, such as during the Younger Dryas, which indicates low-oxygen conditions. This is further supported by the benthic foraminiferal faunal composition. Our results highlight the proxy potential of Mn / Ca in benthic foraminifera from upwelling systems for reconstructing past variations in oxygen conditions of the sea floor environment as well as the need to use it in combination with other proxy records such as faunal assemblage data.
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9.
  • Ning, Wenxin, et al. (författare)
  • Quantitative salinity reconstructions of the Baltic Sea during the mid-Holocene
  • Ingår i: Boreas. - : John Wiley and Sons Ltd. - 0300-9483 .- 1502-3885. ; 46:1, s. 100-110
  • Tidskriftsartikel (refereegranskat)abstract
    • We reconstructed the past coastal environment of the Baltic Sea from c. 7300 to 3500 cal. a BP, with a focus on sea surface salinity (SSS). To quantitatively determine the SSS, two methods were employed: measurements of 87Sr/86Sr ratios in mollusc shells (SSSS r) and process length variations of dinoflagellate cysts Operculodinium centrocarpum (SSSpl). The SSSS r was ~6–7 between 6800 and 6400 cal. a BP, similar to modern conditions. Between 6000 and 3900 cal. a BP, SSSS r was consistently higher, ranging between ~9 and 13. Microfossils sensitive to salinity variations, such as Radiosperma corbiforum and Spiniferites spp., support the SSSS r estimate. In comparison with the SSSS r, the SSSpl values were consistently higher, with an average of ~14. We suggest SSSpl tend to overestimate salinity and are not as reliable as SSSSr. A multi-proxy approach, including analysis of microfossil, organic carbon content, C/N ratios and grain-size, allowed for a division of the study period into three zones (Zones I–III). Zone I (7300–6400 cal. a BP) is characterized by relatively O. centrocarpum and R. corbiforum concentrations, silt contents and C/N ratios, corresponding to the regional Littorina transgression maximum. Zone II (6400–3900 cal. a BP) is characterized by increased Spiniferites spp. and decreased R. corbiforum abundances, and by lowered C/N ratios and silt contents relative to Zone I. Zone III (3900–3500 cal. a BP) represents the start of the Post-Littorina Sea phase, indicating a shift to the modern Baltic Sea phase with decreased salinity.
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10.
  • Polovodova Asteman, Irina, 1980, et al. (författare)
  • Tracing winter temperatures over the last two millennia using a north-east Atlantic coastal record
  • 2018
  • Ingår i: Climate of the Past. - : Copernicus Gesellschaft mbH. - 1814-9324. ; 14:7, s. 1097-1118
  • Tidskriftsartikel (refereegranskat)abstract
    • We present 2500 years of reconstructed bottom water temperatures (BWT) using a fjord sediment archive from the north-east Atlantic region. The BWT represent winter conditions due to the fjord hydrography and the associated timing and frequency of bottom water renewals. The study is based on a ca. 8 m long sediment core from Gullmar Fjord (Sweden), which was dated by Pb-210 and AMS C-14 and analysed for stable oxygen isotopes (delta O-18) measured on shallow infaunal benthic foraminiferal species Cassidulina laevigata d'Orbigny 1826. The BWT, calculated using the palaeotemperature equation from McCorkle et al. (1997), range between 2.7 and 7.8 degrees C and are within the annual temperature variability that has been instrumentally recorded in the deep fjord basin since the 1890s. The record demonstrates a warming during the Roman Warm Period (similar to 350 BCE-450 CE), variable BWT during the Dark Ages (similar to 450-850 CE), positive BWT anomalies during the Viking Age/Medieval Climate Anomaly (similar to 850-1350 CE) and a long-term cooling with distinct multidecadal variability during the Little Ice Age (similar to 1350-1850 CE). The fjord BWT record also picks up the contemporary warming of the 20th century (presented here until 1996), which does not stand out in the 2500-year perspective and is of the same magnitude as the Roman Warm Period and the Medieval Climate Anomaly.
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