Þinghald að fornu : fornleifarannsóknir 2003

No abstract available

Epidemiology and association with outcomes of polypharmacy in patients undergoing surgery: retrospective, population-based cohort study

BACKGROUND: The aim of this study was to determine the prevalence of preoperative polypharmacy and the incidence of postoperative polypharmacy/hyper-polypharmacy in surgical patients and their association with adverse outcomes. METHODS: This was a retrospective, population-based cohort study among patients older than or equal to 18 years undergoing surgery at a university hospital between 2005 and 2018. Patients were categorized based on the number of medications: non-polypharmacy (fewer than 5); polypharmacy (5-9); and hyper-polypharmacy (greater than or equal to 10). The 30-day mortality, prolonged hospitalization (greater than or equal to 10 days), and incidence of readmission were compared between medication-use categories. RESULTS: Among 55 997 patients, the prevalence of preoperative polypharmacy was 32.3 per cent (95 per cent c.i. 33.5 to 34.3) and the prevalence of hyper-polypharmacy was 25.5 per cent (95 per cent c.i. 25.2 to 25.9). Thirty-day mortality was higher for patients exposed to preoperative hyper-polypharmacy (2.3 per cent) and preoperative polypharmacy (0.8 per cent) compared with those exposed to non-polypharmacy (0.6 per cent) (P < 0.001). The hazards ratio (HR) of long-term mortality was higher for patients exposed to hyper-polypharmacy (HR 1.32 (95 per cent c.i. 1.25 to 1.40)) and polypharmacy (HR 1.07 (95 per cent c.i. 1.01 to 1.14)) after adjustment for patient and procedural variables. The incidence of longer hospitalization (greater than or equal to 10 days) was higher for hyper-polypharmacy (11.3 per cent) and polypharmacy (6.3 per cent) compared with non-polypharmacy (4.1 per cent) (P < 0.001). The 30-day incidence of readmission was higher for patients exposed to hyper-polypharmacy (10.2 per cent) compared with polypharmacy (6.1 per cent) and non-polypharmacy (4.8 per cent) (P < 0.001). Among patients not exposed to polypharmacy, the incidence of new postoperative polypharmacy/hyper-polypharmacy was 33.4 per cent (95 per cent c.i. 32.8 to 34.1), and, for patients exposed to preoperative polypharmacy, the incidence of postoperative hyper-polypharmacy was 16.3 per cent (95 per cent c.i. 16.0 to 16.7). CONCLUSION: Preoperative polypharmacy and new postoperative polypharmacy/hyper-polypharmacy are common and associated with adverse outcomes. This highlights the need for increased emphasis on optimizing medication usage throughout the perioperative interval

Þinghald að fornu : fornleifarannsóknir 2003

No abstract available

Using stable isotopes and continuous meltwater river monitoring to investigate the hydrology of a rapidly retreating Icelandic outlet glacier

Virkisjökull is a rapidly retreating outlet glacier draining the western flanks of Öræfajökull in SE Iceland. Since 2011 there have been continuous measurements of flow in the proglacial meltwater channel and regular campaigns to sample stable isotopes δ2H and δ18O from the river, ice, moraine springs and groundwater. The stable isotopes provide reliable end members for glacial ice and shallow groundwater. Analysis of data from 2011 to 2014 indicates that although ice and snowmelt dominate summer riverflow (mean 5.3–7.9 m3 s−1), significant flow is also observed in winter (mean 1.6–2.4 m3 s−1) due primarily to ongoing glacier icemelt. The stable isotope data demonstrate that the influence of groundwater discharge from moraines and the sandur aquifer increases during winter and forms a small (15–20%) consistent source of baseflow to the river. The similarity of hydrological response across seasons reflects a highly efficient glacial drainage system, which makes use of a series of permanent englacial channels within active and buried ice throughout the year. The study has shown that the development of an efficient year round drainage network within the lower part of the glacier has been coincident with the stagnation and subsequent rapid retreat of the glacier

Epidemiology and association with outcomes of polypharmacy in patients undergoing surgery : retrospective, population-based cohort study

© The Author(s) 2023. Published by Oxford University Press on behalf of BJS Society Ltd. Funding Information: This work was supported by the Foundation of St Josef’s Hospital in cooperation with the Icelandic Gerontological Research Centre, the National University Hospital of Iceland (to F.J.), the Landspitali University Hospital Science Fund (to M.I.S.), and the University of Iceland Research Fund (to F.J.). Publisher Copyright: © The Author(s) 2023. Published by Oxford University Press on behalf of BJS Society Ltd.Background: The aim of this study was to determine the prevalence of preoperative polypharmacy and the incidence of postoperative polypharmacy/hyper-polypharmacy in surgical patients and their association with adverse outcomes. Methods: This was a retrospective, population-based cohort study among patients older than or equal to 18 years undergoing surgery at a university hospital between 2005 and 2018. Patients were categorized based on the number of medications: non-polypharmacy (fewer than 5); polypharmacy (5–9); and hyper-polypharmacy (greater than or equal to 10). The 30-day mortality, prolonged hospitalization (greater than or equal to 10 days), and incidence of readmission were compared between medication-use categories. Results: Among 55 997 patients, the prevalence of preoperative polypharmacy was 32.3 per cent (95 per cent c.i. 33.5 to 34.3) and the prevalence of hyper-polypharmacy was 25.5 per cent (95 per cent c.i. 25.2 to 25.9). Thirty-day mortality was higher for patients exposed to preoperative hyper-polypharmacy (2.3 per cent) and preoperative polypharmacy (0.8 per cent) compared with those exposed to non-polypharmacy (0.6 per cent) (P < 0.001). The hazards ratio (HR) of long-term mortality was higher for patients exposed to hyper-polypharmacy (HR 1.32 (95 per cent c.i. 1.25 to 1.40)) and polypharmacy (HR 1.07 (95 per cent c.i. 1.01 to 1.14)) after adjustment for patient and procedural variables. The incidence of longer hospitalization (greater than or equal to 10 days) was higher for hyper-polypharmacy (11.3 per cent) and polypharmacy (6.3 per cent) compared with non-polypharmacy (4.1 per cent) (P < 0.001). The 30-day incidence of readmission was higher for patients exposed to hyper-polypharmacy (10.2 per cent) compared with polypharmacy (6.1 per cent) and non-polypharmacy (4.8 per cent) (P < 0.001). Among patients not exposed to polypharmacy, the incidence of new postoperative polypharmacy/hyper-polypharmacy was 33.4 per cent (95 per cent c.i. 32.8 to 34.1), and, for patients exposed to preoperative polypharmacy, the incidence of postoperative hyper-polypharmacy was 16.3 per cent (95 per cent c.i. 16.0 to 16.7). Conclusion: Preoperative polypharmacy and new postoperative polypharmacy/hyper-polypharmacy are common and associated with adverse outcomes. This highlights the need for increased emphasis on optimizing medication usage throughout the perioperative interval.Peer reviewe

Greenhouse gas balances of managed peatlands in the Nordic countries – present knowledge and gaps

This article provides an overview of the effects of land-use on the fluxes of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;), methane (CH&lt;sub&gt;4&lt;/sub&gt;) and nitrous oxide (N&lt;sub&gt;2&lt;/sub&gt;O) and from peatlands in the Nordic countries based on the field data from about 100 studies. In addition, this review aims to identify the gaps in the present knowledge on the greenhouse gas (GHG) balances associated with the land-use of these northern ecosystems. Northern peatlands have accumulated, as peat, a vast amount of carbon from the atmosphere since the last glaciation. However, the past land-use and present climate have evidently changed their GHG balance. Unmanaged boreal peatlands may act as net sources or sinks for CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; depending on the weather conditions. Drainage for agriculture has turned peatlands to significant sources of GHGs (mainly N&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt;). Annual mean GHG balances including net CH&lt;sub&gt;4&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; emissions are 2260, 2280 and 3140 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt; (calculated using 100 year time horizon) for areas drained for grass swards, cereals or those left fallow, respectively. Even after cessetion of the cultivation practices, N&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; emissions remain high. The mean net GHG emissions in abandoned and afforested agricultural peatlands have been 1580 and 500 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;, respectively. Peat extraction sites are net sources of GHGs with an average emission rate of 770 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;. Cultivation of a perennial grass (e.g., reed canary grass) on an abandoned peat extraction site has been shown to convert such a site into a net sink of GHGs (−330 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;). In contrast, despite restoration, such sites are known to emit GHGs (mean source of 480 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;, mostly from high CH&lt;sub&gt;4&lt;/sub&gt; emissions). Peatland forests, originally drained for forestry, may act as net sinks (mean −780 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;). However, the studies where all three GHGs have been measured at an ecosystem level in the forested peatlands are lacking. The data for restored peatland forests (clear cut and rewetted) indicate that such sites are on average a net sink (190 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;). The mean emissions from drained peatlands presented here do not include emissions from ditches which form a part of the drainage network and can contribute significantly to the total GHG budget. Peat soils submerged under water reservoirs have acted as sources of CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O (mean annual emission 240 g CO&lt;sub&gt;2&lt;/sub&gt; eq. m&lt;sup&gt;−2&lt;/sup&gt;). However, we cannot yet predict accurately the overall greenhouse gas fluxes of organic soils based on the site characteristics and land-use practices alone because the data on many land-use options and our understanding of the biogeochemical cycling associated with the gas fluxes are limited

Microscopy techniques for determining water-cement (w/c) ratio in hardened concrete: A round-robin assessment

Water to cement (w/c) ratio is usually the most important parameter specified in concrete design and is sometimes the subject of dispute when a shortfall in concrete strength or durability is an issue. However, determination of w/c ratio in hardened concrete by testing is very difficult once the concrete has set. This paper presents the results from an inter-laboratory round-robin study organised by the Applied Petrography Group to evaluate and compare microscopy methods for measuring w/c ratio in hardened concrete. Five concrete prisms with w/c ratios ranging from 0.35 to 0.55, but otherwise identical in mix design were prepared independently and distributed to 11 participating petrographic laboratories across Europe. Participants used a range of methods routine to their laboratory and these are broadly divided into visual assessment, measurement of fluorescent intensity and quantitative backscattered electron microscopy. Some participants determined w/c ratio using more than one method or operator. Consequently, 100 individual w/c ratio determinations were collected, representing the largest study of its type ever undertaken. The majority (81%) of the results are accurate to within ± 0.1 of the target mix w/c ratios, 58% come to within ± 0.05 and 37% are within ± 0.025. The study shows that microscopy-based methods are more accurate and reliable compared to the BS 1881-124 physicochemical method for determining w/c ratio. The practical significance, potential sources of errors and limitations are discussed with the view to inform future applications

Sub-surface geology and velocity structure of the Krafla high temperature geothermal field, Iceland : Integrated ditch cuttings, wireline and zero offset vertical seismic profile analysis

The research leading to these results has received funding from the European Community's Seventh Framework Programme under grant agreement No. 608553 (Project IMAGE). The VMAPP project run by VBPR, DougalEARTH Ltd. and TGS also contributed funding to the borehole characterization of the K-18 borehole. Landsvirkun is acknowledged for their effort and assistance in this work and in particular for allowing the use of the data from well K-18. We further acknowledge the support from the Research Council of Norway through its Centres of Excellence funding scheme, project 22372 (SP and DAJ).Peer reviewedPostprin

Synthesis and enantiospecific analysis of enantiostructured triacylglycerols containing n-3 polyunsaturated fatty acids

Publisher's version (útgefin grein)The stereospecific structure of triacylglycerols (TAGs) affects the bioavailability of fatty acids. Lack of enantiopure reference compounds and effective enantiospecific methods have hindered the stereospecific analysis of individual TAGs. Twelve novel enantiostructured AAB-type TAGs were synthesized containing one of the three n-3 polyunsaturated fatty acid: α-linolenic acid (ALA), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) in sn-1 or sn-3 position. These compounds formed six enantiomer pairs, which were separated with recycling high-performance liquid chromatography using chiral columns and UV detection. The chromatographic retention behavior of the enantiomers and the stereospecific elution order were studied. The enantiomer with an n-3 PUFA in the sn-1 position eluted faster than the enantiomer with the n-3 PUFA in the sn-3 position, regardless of the carbon chain length and number of double bonds of the PUFA. TAG enantiomers containing DHA exhibited highly different retention on the chiral column and were separated after the first column, whereas recycling was needed to separate the enantiomer pairs containing ALA or EPA. The system using two identical columns and one mobile phase, without sample derivatization, proved to be very effective also for peak purity assessment, confirming the enantiopurity of the synthesized structured TAGs being higher than 98 % (96 % ee).The authors thank Jani Sointusalo at University of Turku for assistance with the recycling system, Dr. Sigridur Jonsdottir at the Science Institute, University of Iceland, for the accurate mass measurements, Novozymes AS in Denmark for the lipase and Olav Thorstad of Pronova BioPharma ASA in Norway for pure DHA. The work was funded by the Academy of Finland (Decision Nos. 310982 and 315274 ), and the Finnish Cultural Foundation . Haraldur G. Gudmundsson acknowledges financial support for a temporary postdoctoral research at University of Turku and Jóhann D. Magnússon financial support from Lýsi hf. in Iceland .Peer Reviewe