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- Fredh, Daniel, et al.
(author)
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The effect of local land-use changes on floristic diversity during the past 1000 years in southern Sweden
- 2017
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In: Holocene. - : SAGE Publications. - 0959-6836. ; 27:5, s. 694-711
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Journal article (peer-reviewed)abstract
- The relationship between land-use and floristic diversity in the landscape, for the last millennia, is analysed from two small lakes in southern Sweden. Pollen analysis and the Local Vegetation Estimates (LOVE) model are used to quantify land-cover at local scales with 100-year time windows. Floristic richness is estimated using palynological richness, and we introduce LOVE-based evenness as a proxy for floristic evenness on a local scale based on the LOVE output. The results reveal a dynamic land-use pattern, with agricultural expansion during the 13th century, a partly abandoned landscape around AD 1400, re-establishment during the 15th–17th centuries and a transition from traditional to modern land-use during the 20th century. We suggest that the more heterogeneous landscape and the more dynamic land-use during the 13th–19th centuries were of substantial importance for achieving the high floristic diversity that characterises the traditional landscape. Pollen-based studies of this type are helpful in identifying landscape characteristics and land-use practices that are important for floristic diversity and may therefore guide the development of ecosystem management strategies aiming at mitigating the on-going loss of species seen in the landscape of southern Sweden and many other regions worldwide.
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- Geijer, Mats, 1957-, et al.
(author)
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Effective dose in low-dose CT compared with radiography for templating of total hip arthroplasty
- 2017
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In: Acta Radiologica. - London, United Kingdom : Sage Publications. - 0284-1851 .- 1600-0455. ; 58:10, s. 1276-1282
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Journal article (peer-reviewed)abstract
- Background: Recently, total hip arthroplasty (THA) has come to focus on restoration of individual anatomy including femoral neck anteversion and global offset (femoral and acetabular offset). Three-dimensional (3D) computed tomography (CT) data could provide a better basis for preoperative templating. The use of CT has been hampered by high radiation dose.Purpose: To evaluate the effective dose used in pelvis and hip CT for THA templating.Material and Methods: CT data from two clinical trials of THA were evaluated for CT scan length and volume CT dose index (CTDIvol). The effective doses from hip-knee-ankle CT and pelvis and hip radiography were compared. Conversion factors for effective dose for radiography were calculated using the PCXMC software.Results: A reduced dose CT protocol for pelvis imaging gave a substantial dose reduction compared with standard CT, while maintaining sufficient image quality. Between the two clinical trials there was a significant reduction in effective CT dose corresponding to changes in the CT protocol (P<0.01). The CT dose for the latter group was similar to, but nevertheless significantly higher than for, radiography (P<0.01). However, in the latter group the theoretical minimum dose for CT, using the minimum scan length required by the templating software, was equal to the dose from radiography.Conclusion: Although the CT dose remained higher than for radiography, potential reductions in scan length could reduce the dose further so that CTwould have a comparable level of risk to radiography with the added benefit of 3D templating.
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- Hansson, Anton, et al.
(author)
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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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In: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 28:5, s. 721-737
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Journal article (peer-reviewed)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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6. |
- Hansson, Anton, et al.
(author)
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Shoreline Displacement, Coastal Environments and Human Subsistence in the Hanö Bay Region during The Mesolithic
- 2019
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In: Quaternary. - : MDPI AG. - 2571-550X. ; 2:1
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Journal article (peer-reviewed)abstract
- Southern Scandinavia experienced significant environmental changes during the early Holocene. Shoreline displacement reconstructions and results from several zooarchaeological studies were used to describe the environmental changes and the associated human subsistence and settlement development in the Hanö Bay region of southern Sweden during the Mesolithic. GIS-based palaeogeographic reconstructions building on shoreline displacement records from eastern Skåne and western Blekinge together with a sediment sequence from an infilled coastal lake were used to describe the environmental changes during five key periods. The results show a rapid transformation of the coastal landscape during the Mesolithic. During this time, the investigated coastal settlements indicate a shift towards a more sedentary lifestyle and a subsistence focused on large-scale freshwater fishing. The development of permanent settlements coincided with an extended period of coastline stability and the development of rich coastal environments in a more closed forest vegetation. This study provides a regional synthesis of the shoreline displacement, coastal landscape dynamics and settlement development during the Mesolithic. It also demonstrates a new way of combining zooarchaeological and palaeoecological approaches, which can produce multi-faceted and highly resolved palaeoenvironmental reconstructions in a wide range of settings.
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- Moen, Vibeke, et al.
(author)
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Feto-maternal osmotic balance at term. A prospective observational study
- 2018
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In: Journal of Perinatal Medicine. - : WALTER DE GRUYTER GMBH. - 0300-5577 .- 1619-3997. ; 46:2, s. 183-189
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Journal article (peer-reviewed)abstract
- Objective: We performed the present study to investigate the feto-maternal osmotic relationship at term with the hypothesis that, in contrast to the literature, maternal plasma osmolality is lower than fetal levels. In a previous study, we found that maternal plasma sodium at delivery was consistently lower than the sodium in the umbilical artery. Our aim was to corroborate these results with analysis of osmolality. Methods: Blood was sampled from 30 women immediately before cesarean section and from the umbilical artery and vein before cord clamping and osmolality, sodium and albumin were analyzed. Results: Maternal osmolality was (mean; 95% confidence interval) 287.0 (285.8-288.2) mOsmkg/kg, arterial cord osmolality was 289.4 (287.9-291.0) mOsm/kg and venous cord osmolality was 287.3 (286.0-288.5) mOsm/kg. The paired difference between maternal and umbilical arterial osmolality was mean (SD) -2.4 (3.3) mOsm/kg (P amp;lt; 0.001), between maternal and umbilical vein -0.3 (3.0) mOsm/kg (P = 0.63) and between umbilical artery and vein -2.1 (2.8) mOsm/kg (P amp;lt; 0.001). Conclusion: Maternal osmolality was significantly lower than arterial cord osmolality confirming our previous results. The feto-maternal osmotic gradient favors water transport from the mother to the fetus and may increase the fetal risk of water intoxication when the mother ingests or is administered large volumes of electrolyte free solutions.
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- Wastegård, Stefan, et al.
(author)
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Towards a Holocene tephrochronology for the Faroe Islands, North Atlantic
- 2018
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In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 195, s. 195-214
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Journal article (peer-reviewed)abstract
- The Faroe Islands hold a key position in the North Atlantic region for tephra studies due to their relative proximity to Iceland. Several tephras have been described over the last 50 years in peat and lake sediment sequences, including the type sites for the Saksunarvatn and Mjauvotn tephras. Here we present a comprehensive overview of Holocene tephras found on the Faroe Island. In total 23 tephra layers are described including visible macrotephras such as the Saksunarvatn and Hekla 4 tephras and several cryptotephras. The importance of tephras originally described from the Faroe Islands is highlighted and previously unpublished results are included. In addition, full datasets for several sites are published here for the first time. The Saksunarvatn Ash, now considered to be the result of several eruptions rather than one major eruption, can be separated into two phases on the Faroe Islands; one early phase with two precursor eruptions with lower MgO concentrations (4.5-5.0 wt%) than the main eruption and a later phase with higher MgO concentrations (5.5-6.0 wt%), including the visible Saksunarvatn Ash. The Tjornuvik Tephra, previously considered to be a primary deposit, is now interpreted as a reworked tephra with material from at least two middle Holocene eruptions of Hekla. Several of the tephras identified on the Faroe Islands provide useful isochrons for climate events during the Holocene.
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