| 1. |
- Kumarathunge, Dushan P., et al.
(författare)
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Acclimation and adaptation components of the temperature dependence of plant photosynthesis at the global scale
- 2019
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Ingår i: New Phytologist. - : John Wiley & Sons. - 0028-646X .- 1469-8137. ; 222:2, s. 768-784
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Tidskriftsartikel (refereegranskat)abstract
- The temperature response of photosynthesis is one of the key factors determining predicted responses to warming in global vegetation models (GVMs). The response may vary geographically, owing to genetic adaptation to climate, and temporally, as a result of acclimation to changes in ambient temperature. Our goal was to develop a robust quantitative global model representing acclimation and adaptation of photosynthetic temperature responses.We quantified and modelled key mechanisms responsible for photosynthetic temperature acclimation and adaptation using a global dataset of photosynthetic CO2 response curves, including data from 141 C3 species from tropical rainforest to Arctic tundra. We separated temperature acclimation and adaptation processes by considering seasonal and common-garden datasets, respectively.The observed global variation in the temperature optimum of photosynthesis was primarily explained by biochemical limitations to photosynthesis, rather than stomatal conductance or respiration. We found acclimation to growth temperature to be a stronger driver of this variation than adaptation to temperature at climate of origin.We developed a summary model to represent photosynthetic temperature responses and showed that it predicted the observed global variation in optimal temperatures with high accuracy. This novel algorithm should enable improved prediction of the function of global ecosystems in a warming climate.
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| 2. |
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| 3. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 4. |
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| 5. |
- Jakobsson, Martin, 1966-, et al.
(författare)
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An Arctic Ocean ice shelf during MIS 6 constrained by new geophysical and geological data
- 2010
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 29:25-26, s. 3505-3517
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis of floating ice shelves covering the Arctic Ocean during glacial periods was developed in the 1970s. In its most extreme form, this theory involved a 1000 m thick continuous ice shelf covering the Arctic Ocean during Quaternary glacial maxima including the Last Glacial Maximum (LGM). While recent observations clearly demonstrate deep ice grounding events in the central Arctic Ocean, the ice shelf hypothesis has been difficult to evaluate due to a lack of information from key areas with severe sea ice conditions. Here we present new data from previously inaccessible, unmapped areas that constrain the spatial extent and timing of marine ice sheets during past glacials. These data include multibeam swath bathymetry and subbottom profiles portraying glaciogenic features on the Chukchi Borderland, southern Lomonosov Ridge north of Greenland, Morris Jesup Rise, and Yermak Plateau. Sediment cores from the mapped areas provide age constraints on the glaciogenic features. Combining these new geophysical and geological data with earlier results suggests that an especially extensive marine ice sheet complex, including an ice shelf, existed in the Amerasian Arctic Ocean during Marine Isotope Stage (MIS) 6. From a conceptual oceanographic model we speculate that the cold halocline of the Polar Surface Water may have extended to deeper water depths during MIS 6 inhibiting the warm Atlantic water from reaching the Amerasian Arctic Ocean and, thus, creating favorable conditions for ice shelf development. The hypothesis of a continuous 1000 m thick ice shelf is rejected because our mapping results show that several areas in the central Arctic Ocean substantially shallower than 1000 m water depth are free from glacial influence on the seafloor.
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| 6. |
- Wallin, Paul, 1961-, et al.
(författare)
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Re-dating Ahu Nau Nau and the Settlement at 'Anakena, Rapa Nui
- 2010
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Ingår i: The Gotland Papers. - Visby : Gotland University. - 9789186343071 ; , s. 37-46
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The building phase and early use of Ahu Nau Nau have been re-dated by nine charcoal and rat bone samples. The new dates in comparison with earlier data suggest that the ahu was constructed around 650-550 BP. It is also suggested that a settlement dated to c. 950-900 BP preceded the ahu-building phase. A new question in light of recent research might be raised: Is the earliest settlement on Rapa Nui found at ´Anakena or should we look elsewhere?
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| 7. |
- Abraham-Nordling, Mirna, et al.
(författare)
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Incidence of hyperthyroidism in Sweden
- 2011
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Ingår i: European Journal of Endocrinology. - 0804-4643 .- 1479-683X. ; 165:6, s. 899-905
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The incidence of hyperthyroidism has been reported in various countries to be 23-93/100000 inhabitants per year. This extended study has evaluated the incidence for similar to 40% of the Swedish population of 9 million inhabitants. Sweden is considered to be iodine sufficient country. Methods:All patients including children, who were newly diagnosed with overt hyperthyroidism in the years 2003-2005, were prospectively registered in a multicenter study. The inclusion criteria are as follows:clinical symptoms and/or signs of hyperthyroidism with plasma TSH concentration below 0.2 mIE/l and increased plasma levels of free/total triiodothyronine and/or free/total thyroxine. Patients with relapse of hyperthyroidism or thyroiditis were not included. The diagnosis of Graves' disease (GD), toxic multinodular goiter (TMNG) and solitary toxic adenoma (STA), smoking, initial treatment, occurrence of thyroid-associated eye symptoms/signs, and demographic data were registered. Results:A total of 2916 patients were diagnosed with de novo hyperthyroidism showing the total incidence of 27.6/100 000 inhabitants per year. The incidence of GD was 21.0/100 000 and toxic nodular goiter (TNG=STA+TMNG) occurred in 692 patients, corresponding to an annual incidence of 6.5/100 000. The incidence was higher in women compared with men (4.2:1). Seventy-five percent of the patients were diagnosed with GD, in whom thyroid-associated eye symptoms/signs occurred during diagnosis in every fifth patient. Geographical differences were observed. Conclusion:The incidence of hyperthyroidism in Sweden is in a lower range compared with international reports. Seventy-five percent of patients with hyperthyroidism had GD and 20% of them had thyroid-associated eye symptoms/signs during diagnosis. The observed geographical differences require further studies.
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| 8. |
- af Ekenstam, Angelica, et al.
(författare)
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Leaf respiration rates are increased by warm season as well as by elevated temperature treatment in Eucalyptus globulus
- 2014
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Ingår i: EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Plant leaf respiration is one of the major CO2 fluxes between terrestrial biosphere and the atmosphere, and its responses to elevated CO2 and temperature thus have important implications for the carbon cycle and rate on ongoing climate change. Non-photorespiratory leaf respiration is reduced in light, Rlight, compared with the rate in the dark, Rdark. It is therefore important to consider both Rlight and Rdark when estimating the exchange of CO2 between the biosphere and the atmosphere, during current and future climates. This study was conducted at the Hawkesbury Forest Experiment, HFE, in Richmond, NSW, Australia. Trees of Tasmanian Blue Gum (Eucalyptus globulus Labill.) were exposed in whole tree chambers (WTC) to a complete factorial combination of ambient and elevated temperature and CO2 (+3 °C and +240 ppm CO2, respectively). The measurements of Rlight and Rdark were made in 2011 after 15 month exposure in the WTCs. The measurements were made in March (after the year’s hottest months) and October (after the coldest period). Rlight was determined at four temperatures ranging between 20 and 40 °C on attached leaves using a portable gas exchange system (LI-6400XT). Rdark was measured at 20-40 °C in October and at 25 °C in March. Rdark was measured after dark acclimation for at least 30 min and Rlight was determined from the intersection of the photosynthetic CO2 responses measured at three different light intensities using the Laisk metod. Trees grown in elevated temperature had a considerably higher Rdark (+53% across all measurement temperatures in October). However, Rlight did not respond significantly to either CO2 or temperature. In October, the Rlight to Rdark ratio indicated an overall light inhibition of respiration of 31% across all temperatures and in March the light inhibition was 22 % at 25 °C. The seasonal comparisons showed that both Rlight and Rdark were considerably higher after the warm compared to cold season, especially when measured at high temperature. These results points out the importance to account for Rlight as well as seasonal thermal respiratory acclimation when improving predictions of the carbon exchange between tree canopies and the atmosphere. If not taking light inhibition into account, leaf respiration is being overestimated and if not taking the seasonal acclimation into account the errors are potentially very large.
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| 9. |
- Ahl, Rebecka, 1987-, et al.
(författare)
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Does beta-blockade reduce the risk of depression in patients with isolated severe extracranial injuries?
- 2017
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Ingår i: World Journal of Surgery. - New York : Springer. - 0364-2313 .- 1432-2323. ; 41:7, s. 1801-1806
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Approximately half of trauma patients develop post-traumatic depression. It is suggested that beta-blockade impairs trauma memory recollection, reducing depressive symptoms. This study investigates the effect of early beta-blockade on depression following severe traumatic injuries in patients without significant brain injury.METHODS: Patients were identified by retrospectively reviewing the trauma registry at an urban university hospital between 2007 and 2011. Severe extracranial injuries were defined as extracranial injuries with Abbreviated Injury Scale score ≥3, intracranial Abbreviated Injury Scale score <3 and an Injury Severity Score ≥16. In-hospital deaths and patients prescribed antidepressant therapy ≤1 year prior to admission were excluded. Patients were stratified into groups based on pre-admission beta-blocker status. The primary outcome was post-traumatic depression, defined as receiving antidepressants ≤1 year following trauma.RESULTS: Five hundred and ninety-six patients met the inclusion criteria with 11.4% prescribed pre-admission beta-blockade. Patients receiving beta-blockers were significantly older (57 ± 18 vs. 42 ± 17 years, p < 0.001) with lower Glasgow Coma Scale score (12 ± 3 vs. 14 ± 2, p < 0.001). The beta-blocked cohort spent significantly longer in hospital (21 ± 20 vs. 15 ± 17 days, p < 0.01) and intensive care (4 ± 7 vs. 3 ± 5 days, p = 0.01). A forward logistic regression model was applied and predicted lack of beta-blockade to be associated with increased risk of depression (OR 2.7, 95% CI 1.1-7.2, p = 0.04). After adjusting for group differences, patients lacking beta-blockers demonstrated an increased risk of depression (AOR 3.3, 95% CI 1.2-8.6, p = 0.02).CONCLUSIONS: Pre-admission beta-blockade is associated with a significantly reduced risk of depression following severe traumatic injury. Further investigation is needed to determine the beneficial effects of beta-blockade in these instances.
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| 10. |
- Ahl, Rebecka, 1987-
(författare)
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The Association Between Beta-Blockade and Clinical Outcomes in the Context of Surgical and Traumatic Stress
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic injury and major abdominal surgery are areas in general surgery associated with high rates of morbidity and mortality. The overall colorectal cancer surgery mortality rate is around 4%, with that for emergency surgery more than twice as high as for planned. Surgical morbidity varies between 25% and 45%. Around half of trauma patients develop low mood. In one quarter of patients this becomes permanent. Depression is known to impede physical rehabilitation and recovery. The onset of physiological stress, driven by adrenergic hyperactivity following traumatic and surgical injury is hypothesized to contribute to these adverse outcomes. Interest has therefore been sparked into blocking adrenergic receptor activation.Papers I and II investigated the role of beta-blocker therapy in preventing post-traumatic depression following severe traumatic brain injury (Paper I) and severe extracranial injury (Paper II). The Karolinska University Hospital Trauma Registry was used to identify patients admitted between 2007 and 2011. In Paper I (n = 545), patients on pre-injury beta-blocker therapy were matched to beta-blocker naïve patients with equivalent injury burden. Results revealed that beta-blocked patients exhibited a 60% reduced risk of needing antidepressant therapy within one year of trauma. In Paper II (n = 596), the lack of beta-blocker use before extracranial trauma was linked to a three-fold increase in the risk of antidepressant initiation.Papers III-V explored the role of pre-operative beta-blocker therapy in patients undergoing surgery for colorectal cancer between 2007 and 2016, identified using the nationwide Swedish Colorectal Cancer Registry. Paper III (n = 3,187) identified a 69% reduction in the risk of 30-day mortality in beta-blocked patients. Paper IV (n = 22,337) outlined long-term survival benefits for patients on beta-blocker therapy prior to undergoing elective surgery for colon cancer. Beta-blocked patients showed a risk reduction of 42% for 1-year all-cause mortality and 18% for 5-year cancerspecific mortality. Similarly, patients on beta-blocker therapy who underwent surgery for rectal cancer demonstrated improved survival up to one year after surgery with a risk reduction of 57% and a reduction in anastomotic failure and infectious complications in Paper V (n = 11,966).
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| 11. |
- Apel, Jan, et al.
(författare)
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Early Holocene human population events on the island of Gotland in the Baltic Sea (9200-3800 cal. BP)
- 2018
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Ingår i: Quaternary International. - : Elsevier BV. - 1040-6182 .- 1873-4553. ; 465, s. 276-286
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Tidskriftsartikel (refereegranskat)abstract
- The summed probability distribution of 162 radiocarbon dates from Gotland was analysed with reference to archaeological and environmental data in order to evaluate possible variations in settlement intensity on the island. The data indicated variations in demographic development on the island, with probably several different colonization events and external influences; the pioneer settlement reached the island around 9200 cal. BP. After the initial colonization, the radiocarbon dates were rather evenly distributed until around 7700–7600 cal. BP, then there was a drop in the number of dates between 8300 and 8000 cal. BP that may be associated with the 8200 cold event. A marked decline in the number of dates between 7600 and 6000 cal. BP may be associated initially with the Littorina I transgression, but this transgression cannot explain why the Late Mesolithic period is not well represented on Gotland: the climatic development was favourable but did not result in increased human activity. The number of radiocarbon dates indicated that the population size remained low until around 6000 cal. BP, after which there was a gradual increase that reached a first ‘threshold’ after 5600 cal. BP and a second ‘threshold’ after 4500 cal. BP. The first apparent population increase was associated with the appearance of the Funnel Beaker Culture (FBC) and the second with Pitted Ware Culture (PWC) complexes. A decline in the number of dates occurred after 4300 cal. BP, i.e. towards the Late Neolithic. There was an association between the frequency distributions of the radiocarbon dates and the number of stray finds from different time periods but any correlation was not straightforward.
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| 12. |
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| 13. |
- Boukharta, Lars, et al.
(författare)
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Computer Simulations of Structure-Activity Relationships for hERG Channel Blockers
- 2011
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 50:27, s. 6146-6156
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Tidskriftsartikel (refereegranskat)abstract
- The hERG potassium channel is of major pharmaceutical importance, and its blockade by various compounds, potentially causing serious cardiac side effects, is a major problem in drug development. Despite the large amounts of existing biochemical data on blockade of hERG by drugs and druglike compounds, relatively little is known regarding the structural basis of binding of blockers to the channel. Here, we have used a recently developed homology model of hERG to conduct molecular docking experiments with a series of channel blockers, followed by molecular dynamics simulations of the complexes and evaluation of binding free energies with the linear interaction energy method. The calculations yield a remarkably good agreement with experimental binding affinities and allow for a rationalization of three-dimensional structure-activity relationships in terms of a number of key interactions. Two main interaction regions of the channel are thus identified with implications for further mutagenesis experiments and design of new compounds.
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| 14. |
- Crouse, Kristine, et al.
(författare)
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Acclimation of light and dark respiration to experimental and seasonal warming are mediated by changes in leaf nitrogen in Eucalyptus globulus
- 2017
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Ingår i: Tree Physiology. - : Oxford University Press (OUP). - 0829-318X .- 1758-4469. ; 37:8, s. 1069-1083
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Tidskriftsartikel (refereegranskat)abstract
- Quantifying the adjustments of leaf respiration in response to seasonal temperature variation and climate warming is crucial because carbon loss from vegetation is a large but uncertain part of the global carbon cycle. We grew fast-growing Eucalyptus globulus Labill. trees exposed to +3 °C warming and elevated CO2 in 10-m tall whole-tree chambers and measured the temperature responses of leaf mitochondrial respiration, both in light (RLight) and in darkness (RDark), over a 20–40 °C temperature range and during two different seasons. RLight was assessed using the Laisk method. Respiration rates measured at a standard temperature (25 °C – R25) were higher in warm-grown trees and in the warm season, related to higher total leaf nitrogen (N) investment with higher temperatures (both experimental and seasonal), indicating that leaf N concentrations modulated the respiratory capacity to changes in temperature. Once differences in leaf N were accounted for, there were no differences in R25 but the Q10 (i.e., short-term temperature sensitivity) was higher in late summer compared with early spring. The variation in RLight between experimental treatments and seasons was positively correlated with carboxylation capacity and photorespiration. RLight was less responsive to short-term changes in temperature than RDark, as shown by a lower Q10 in RLight compared with RDark. The overall light inhibition of R was ∼40%. Our results highlight the dynamic nature of leaf respiration to temperature variation and that the responses of RLight do not simply mirror those of RDark. Therefore, it is important not to assume that RLight is the same as RDark in ecosystem models, as doing so may lead to large errors in predicting plant CO2 release and productivity.
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| 15. |
- Dahle, B., et al.
(författare)
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Predation on adult moose Alces alces by European brown bears Ursus arctos
- 2013
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 19:2, s. 165-169
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Tidskriftsartikel (refereegranskat)abstract
- Several North American studies have reported significant predation rates on moose Alces alces by brown bears Ursus arctos. We documented predation on moose by brown bears in south-central Sweden, where brown bears and moose occurred at estimated densities of 10-30 and 400-1,340/1,000 km(2), respectively. Bears killed 0.8% of radio-collared adult female moose (i.e. >= 1 year old) annually and no male moose (>= 1 year old). Bear predation was the least important mortality factor we documented. Based on tracking brown bears on snow during spring we recorded one successful hunt for every 372 km of tracks and documented attacks only by adult bears and successful attacks only by adult males. Autopsy of moose older than calves that were killed by brown bears revealed that yearlings were more prone to predation than older moose, and that older (i.e. >= 2 years) cows were more vulnerable to predation than older bulls. Our study suggests a lower tendency for Scandinavian brown bears to prey on moose compared to most of the North American studies.
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| 16. |
- Dammeyer, Pascal, et al.
(författare)
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Cisplatin and oxaliplatin are toxic to cochlear outer hair cells and both target thioredoxin reductase in organ of Corti cultures
- 2014
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 134:5, s. 448-454
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Tidskriftsartikel (refereegranskat)abstract
- Conclusion: Inhibition of thioredoxin reductase (TrxR) may be a contributing factor in cisplatin- induced ototoxicity. Direct exposure of organ of Corti to cisplatin and oxaliplatin gives equal loss of hair cells. Objectives: Platinum- containing drugs are known to target the anti- oxidant selenoprotein TrxR in cancer cells. Two such anti- cancer, platinum- containing drugs, cisplatin and oxaliplatin, have different side effects. Only cisplatin induces hearing loss, i.e. has an ototoxic side effect that is not seen after treatment with oxaliplatin. The objective of this study was to evaluate if TrxR is a target in the cochlea. Loss of outer hair cells was also compared when cisplatin and oxaliplatin were administered directly to the organ of Corti. Methods: Organ of Corti cell culture was used for direct exposure to cisplatin and oxaliplatin. Hair cells were evaluated and the level of TrxR was assessed. Immunohistochemical staining for TrxR was performed. An animal model was used to evaluate the effect on TrxR after treatment with cisplatin and oxaliplatin in vivo. Results: Direct exposure of cochlear organotypic cultures to either cisplatin or oxaliplatin induced comparable levels of outer hair cell loss and inhibition of TrxR, demonstrating that both drugs are similarly ototoxic provided that the cochlea becomes directly exposed.
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| 17. |
- Dewar, R. C., et al.
(författare)
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Why does leaf nitrogen decline within tree canopies less rapidly than light? An explanation from optimization subject to a lower bound on leaf mass per area
- 2012
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Ingår i: Tree Physiology. - : Oxford University Press (OUP). - 0829-318X .- 1758-4469. ; 32:5, s. 520-534
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Tidskriftsartikel (refereegranskat)abstract
- A long-established theoretical result states that, for a given total canopy nitrogen (N) content, canopy photosynthesis is maximized when the within-canopy gradient in leaf N per unit area (N-a) is equal to the light gradient. However, it is widely observed that N-a declines less rapidly than light in real plant canopies. Here we show that this general observation can be explained by optimal leaf acclimation to light subject to a lower-bound constraint on the leaf mass per area (m(a)). Using a simple model of the carbon-nitrogen (C-N) balance of trees with a steady-state canopy, we implement this constraint within the framework of the MAXX optimization hypothesis that maximizes net canopy C export. Virtually all canopy traits predicted by MAXX (leaf N gradient, leaf N concentration, leaf photosynthetic capacity, canopy N content, leaf-area index) are in close agreement with the values observed in a mature stand of Norway spruce trees (Picea abies L. Karst.). An alternative upper-bound constraint on leaf photosynthetic capacity (A(sat)) does not reproduce the canopy traits of this stand. MAXX subject to a lower bound on m(a) is also qualitatively consistent with co-variations in leaf N gradient, m(a) and A(sat) observed across a range of temperate and tropical tree species. Our study highlights the key role of constraints in optimization models of plant function.
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| 18. |
- Donadio, V., et al.
(författare)
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Muscle sympathetic response to arousal predicts neurovascular reactivity during mental stress
- 2012
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Ingår i: Journal of Physiology-London. - : Wiley. - 0022-3751. ; 590:12, s. 2885-2896
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Tidskriftsartikel (refereegranskat)abstract
- Key points Mental stress (MS) is often initiated by a sensory or cognitive stimulus, which induces a brief arousal reaction followed by a longer stress phase. Both phases induce blood pressure (BP) increases whereas effects on muscle sympathetic nerve activity (MSNA) vary: in approximately 50% of healthy subjects (responders) arousal induces a brief MSNA reduction, which is absent in the remaining 50% (non-responders). We now report a link between the arousal response and neurovascular effects of MS in healthy males. Our data show that during MS, responders to arousal exhibited a significant decrease of MSNA and a lesser BP increase compared to non-responders. The whole material displayed a positive correlation between MSNA responses induced by arousal and MS. In addition, arousal induced MSNA changes correlated positively with BP changes during MS. We conclude that the MSNA response to arousal predicts MSNA and BP responses to MS.
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| 19. |
- Dusenge, Mirindi Eric, 1986, et al.
(författare)
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Photosynthetic capacities of mature tropical forest trees in Rwanda are linked to successional group identity rather than to leaf nutrient content
- 2014
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Ingår i: EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Tropical forests are crucial in the global carbon balance, yet information required to estimate how much carbon that enter these ecosystems through photosynthesis is very limited, in particular for Africa and for tropical montane forests. In order to increases the knowledge of natural variability of photosynthetic capacities in tropical tree species in tropical Africa, measurements of leaf traits and gas exchange were conducted on sun and shade leaves of ten tree species growing in two tropical forests in Rwanda in central Africa. Seven species were studied in Ruhande Arboretum, a forest plantation at mid altitude (ca 1700 m), and six species in Nyungwe National Park, a cooler and higher altitude (at ca 2500 m) montane rainforest. Three species were common to both sites. At Nyungwe, three species each belonged to the successional groups pioneer and climax species. Climax species had considerably lower maximum rates of photosynthetic carboxylation (Vcmax) and electron transport (Jmax) than pioneer species. This difference was not related to leaf nutrient content, but rather seemed to be caused by differences in within-leaf N allocation between the two successional groups. With respect to N, leaves of climax species invested less N into photosynthetic enzymes (as judged by lower Vcmax and Jmax values) and more N into chlorophyll (as judged by higher SPAD values). Photosynthetic capacities, (i.e., Jmax and Vcmax), Jmax:Vcmax ratio and P content were significantly higher in Nyungwe than in Arboretum. Sun leaves had higher photosynthetic capacities and nutrient content than shade leaves. Across the entire dataset, variation in photosynthetic capacities among species was not related to leaf nutrient content, although significant relationships were found within individual species. This study contributes critical tropical data for global carbon models and suggests that, for montane rainforest trees of different functional types, successional group identity is a better predictor of photosynthetic capacities than leaf nutrient content.
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| 20. |
- Dusenge, Mirindi Eric, 1986, et al.
(författare)
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Photosynthetic capacity of tropical montane tree species in relation to leaf nutrients, successional strategy and growth temperature
- 2015
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 177:4, s. 1183-1194
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Tidskriftsartikel (refereegranskat)abstract
- Photosynthetic capacity of tree leaves is typically positively related to nutrient content and little affected by changes in growth temperature. These relationships are, however, often poorly supported for tropical trees, for which interspecific differences may be more strongly controlled by within-leaf nutrient allocation than by absolute leaf nutrient content, and little is known regarding photosynthetic acclimation to temperature. To explore the influence of leaf nutrient status, successional strategy and growth temperature on the photosynthetic capacity of tropical trees, we collected data on photosynthetic, chemical and morphological leaf traits of ten tree species in Rwanda. Seven species were studied in a forest plantation at mid-altitude (~1,700 m), whereas six species were studied in a cooler montane rainforest at higher altitude (~2,500 m). Three species were common to both sites, and, in the montane rainforest, three pioneer species and three climax species were investigated. Across species, interspecific variation in photosynthetic capacity was not related to leaf nutrient content. Instead, this variation was related to differences in within-leaf nitrogen allocation, with a tradeoff between investments into compounds related to photosynthetic capacity (higher in pioneer species) versus light-harvesting compounds (higher in climax species). Photosynthetic capacity was significantly lower at the warmer site at 1,700 m altitude. We conclude that (1) within-leaf nutrient allocation is more important than leaf nutrient content per se in controlling interspecific variation in photosynthetic capacity among tree species in tropical Rwanda, and that (2) tropical montane rainforest species exhibit decreased photosynthetic capacity when grown in a warmer environment.
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| 21. |
- Dusenge, Mirindi Eric, 1986, et al.
(författare)
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Photosynthetic capacity of tropical montane tree species in relation to leaf nutrients, successional strategy and growth temperature
- 2015
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Ingår i: 2015 Canadian Society of Plant Biologist/Eastern Regional meeting; University of Toronto, St George Campus, November 21-22nd, 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Photosynthetic capacity of tree leaves is typically positively related to nutrient content and little affected by changes in growth temperature. These relationships are, however, often poorly supported for tropical trees, for which interspecific differences may be more controlled by within-leaf nutrient allocation than by absolute leaf nutrient content, and little is known regarding photosynthetic acclimation to temperature. To explore the influence of leaf nutrient status, successional strategy and growth temperature on the photosynthetic capacity of tropical trees, we collected data on photosynthetic, chemical and morphological leaf traits of ten tree species in Rwanda. Seven species were studied in a forest plantation at mid-altitude, whereas six species were studied in a cooler montane rainforest at higher altitude. Three species were common to both sites, and, in the montane rainforest, three pioneer species and three climax species were investigated. Across species, interspecific variation in photosynthetic capacity was not related to leaf nutrient content. Instead, this variation was related to differences in within-leaf nitrogen allocation, with a tradeoff between investments into compounds related to photosynthetic capacity (higher in pioneer species) versus light-harvesting compounds (higher in climax species). Photosynthetic capacity was significantly lower at the warmer site. We conclude that (1) within-leaf nutrient allocation is more important than leaf nutrient content per se in controlling interspecific variation in photosynthetic capacity among tree species in tropical Rwanda, and that (2) tropical montane rainforest species exhibit decreased photosynthetic capacity when grown in a warmer environment.
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| 22. |
- Ekblom, Maria, 1974-, et al.
(författare)
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Device-Measured Sedentary Behavior, Physical Activity and Aerobic Fitness Are Independent Correlates of Cognitive Performance in Healthy Middle-Aged Adults-Results from the SCAPIS Pilot Study.
- 2019
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 16:24
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Tidskriftsartikel (refereegranskat)abstract
- High aerobic fitness, more moderate to vigorous physical activity (MVPA) and less sedentary behavior (SED) have all been suggested to promote cognitive functions, but it is unclear whether they are independent predictors of specific cognitive domains. This study aimed to investigate to what extent aerobic fitness MVPA and SED are independently associated with cognitive performance among middle-aged Swedish adults. We acquired device-based measures of aerobic fitness, cognitive performance and percent daily time spent in MVPA and SED in Swedish adults (n = 216; 54-66 years old). Aerobic fitness was associated with better performance at one out of two tests of speed/attention and one out of four tests of executive attention, and with worse performance at one of seven tests of memory. Increasing %MVPA was associated with better performance at one out of seven tests of memory and two out of three tests of verbal ability, whereas increasing %SED was associated with better performance at all four tests of executive attention and four out of seven tests of memory. These findings suggest that aerobic fitness, %MVPA and %SED are partly independent correlates of cognitive performance. To fully understand the association between SED and performance at several tests of cognitive function, future investigations might attempt to investigate intellectually engaging SED (such as reading books) separately from mentally undemanding SED (such as watching TV).
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| 23. |
- Falhammar, Henrik, et al.
(författare)
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Acute suppurative thyroiditis with thyroid abscess in adults : clinical presentation, treatment and outcomes
- 2019
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Ingår i: BMC Endocrine Disorders. - : BioMed Central (BMC). - 1472-6823. ; 19:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Abscess in the thyroid gland is a rare but severe infectious disease. The condition can have anatomic or iatrogenic underlying causes. If untreated it could be fatal. Pathogens vary considerably. Treatment is intravenous antibiotics, drainage, and sometimes surgery.METHODS: The electronic medical records of all adult patients with acute thyroiditis 2003-2017 treated at the Karolinska University Hospital (catchment area 2 million) in Sweden were systematically reviewed.RESULTS: Five patients were found in the catchment area. One patient from another region but known to us was also included. Thus, six patients (aged 28-73 years) were included in the study. Median length of hospital stay was 7.5 days (4-79 days). All were treated with antibiotics (intravenous n = 5, oral n = 1). Total antibiotic treatment duration was 13.5 days (10-41 days). Blood cultures were positive in three (streptococcus pneumonia, streptococci sanguineous, pepto streptococci), deep tissue culture in three (Escherichia coli, Candida, Hemophilic influenza) and no positive culture at all in two. Drainage was used in three patients. All patients recovered without recurrences. Surgery was performed twice in the acute phase in one. There was no recurrence during 7 years (3-12) of follow-up, but one patient died after three years (severe heart failure and pneumonia).CONCLUSION: Thyroid abscess in adults is extremely rare nowadays in the developed world. With prompt antibiotic therapy, drainage and in some cases thyroidectomy the prognosis seems favourable.
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| 24. |
- Feng, Zhaozhong, et al.
(författare)
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Constraints to nitrogen acquisition of terrestrial plants under elevated CO2
- 2015
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 21:8, s. 3152-3168
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Tidskriftsartikel (refereegranskat)abstract
- A key part of the uncertainty in terrestrial feedbacks on climate change is related to how and to what extent nitrogen (N) availability constrains the stimulation of terrestrial productivity by elevated CO2 (eCO2), and whether or not this constraint will become stronger over time. We explored the ecosystem-scale relationship between responses of plant productivity and N acquisition to eCO2 in Free-Air CO2 Enrichment (FACE) experiments in grassland, cropland and forest ecosystems and found that: (i) In all three ecosystem types, this relationship was positive, linear, and strong (r2 = 0.68), but exhibited a negative intercept such that plant N acquisition was decreased by 10% when eCO2 caused neutral or modest changes in productivity. Since the ecosystems were markedly N limited, plants with minimal productivity responses to eCO2 likely acquired less N than ambient CO2-grown counterparts because access was decreased, and not because demand was lower. (ii) Plant N concentration was lower under eCO2, and this decrease was independent of the presence or magnitude of eCO2-induced productivity enhancement, refuting the long-held hypothesis that this effect results from growth dilution. (iii) Effects of eCO2 on productivity and N acquisition did not diminish over time, while the typical eCO2-induced decrease in plant N concentration did. Our results suggest that, at the decennial time scale covered by FACE studies, N limitation of eCO2-induced terrestrial productivity enhancement is associated with negative effects of eCO2 on plant N acquisition rather than with growth dilution of plant N or processes leading to progressive N limitation.
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| 25. |
- Gharahi Ghehi, N., et al.
(författare)
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N2O and NO emission from the Nyungwe tropical highland rainforest in Rwanda
- 2014
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Ingår i: Geoderma Regional. - 2352-0094. ; 2-3, s. 41-49
-
Tidskriftsartikel (refereegranskat)abstract
- Tropical forest soils are a significant source for N2O and NO. Current estimates of N2O and NO emissions are uncertain due to the limited number of fieldmeasurements and model input data. Furthermore, considerable spatial and temporal variability exists due to variation of soil properties, vegetation characteristics and meteorology.We used a process-based model (ForestDNDC-tropica) to estimate N2O and NO emissions from the entire (970 km2) tropical highland forest (Nyungwe) in southwestern Rwanda. Scaling these results to that regional level using legacy soil, meteorological and simulated vegetation data we found in most cases agreement between N2O and NO measurements and model predictions. Limited agreement was found for acid soils with high clay content and reduced metals, indicating that abiotic N2O and NO forming processes in acidic soils might be under-represented in the current ForestDNDC-tropica model. The Nyungwe forest was estimated to emit 439 t N2O-N year−1 (2.8– 5.5 kg N2O-N ha−1 year−1) and 244 t NO-N year−1 (0.8–5.1 kg N ha−1 year−1), corroborating previous studies in tropical forests and highlighting that also tropical highland rainforest soils are a major source of atmospheric N2O and NO. The uncertainty for the N2O and NO emission estimates was 153 and 50 t N2O-N year−1 and 36 and 16 t NO-N year−1 considering uncertainty in model input data and annual variability, respectively. The results showed that soil bulk density and pH were the most influential factors driving spatial variation and model uncertainty. To improve global model-based estimates of N2O and NO emission from tropical forest focus should therefore also be oriented in delivering more detailed soil and vegetation data.
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| 26. |
- Giesecke, Peter, et al.
(författare)
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All-cause and cardiovascular mortality risk after surgery versus radioiodine treatment for hyperthyroidism
- 2018
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Ingår i: British Journal of Surgery. - : John Wiley & Sons. - 0007-1323 .- 1365-2168. ; 105:3, s. 279-286
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Little is known about the long-term side-effects of different treatments for hyperthyroidism. The few studies previously published on the subject either included only women or focused mainly on cancer outcomes. This register study compared the impact of surgery versus radioiodine on all-cause and cause-specific mortality in a cohort of men and women.METHODS: Healthcare registers were used to find hyperthyroid patients over 35 years of age who were treated with radioiodine or surgery between 1976 and 2000. Comparisons between treatments were made to assess all-cause and cause-specific deaths to 2013. Three different statistical methods were applied: Cox regression, propensity score matching and inverse probability weighting.RESULTS: Of the 10 992 patients included, 10 250 had been treated with radioiodine (mean age 65·1 years; 8668 women, 84·6 per cent) and 742 had been treated surgically (mean age 44·1 years; 633 women, 85·3 per cent). Mean duration of follow-up varied between 16·3 and 22·3 years, depending on the statistical method used. All-cause mortality was significantly lower among surgically treated patients, with a hazard ratio of 0·82 in the regression analysis, 0·80 in propensity score matching and 0·85 in inverse probability weighting. This was due mainly to lower cardiovascular mortality in the surgical group. Men in particular seemed to benefit from surgery compared with radioiodine treatment.CONCLUSION: Compared with treatment with radioiodine, surgery for hyperthyroidism is associated with a lower risk of all-cause and cardiovascular mortality in the long term. This finding was more evident among men.
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| 27. |
- Giesecke, Peter, et al.
(författare)
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Increased Cardiovascular Mortality and Morbidity in Patients Treated for Toxic Nodular Goiter Compared to Graves' Disease and Nontoxic Goiter
- 2017
-
Ingår i: Thyroid. - : Mary Ann Liebert. - 1050-7256 .- 1557-9077. ; 27:7, s. 878-885
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Previous research has suggested an increased risk of death and cardiovascular disease in patients treated for hyperthyroidism. However, studies on this subject are heterogeneous, often based on old data, or have not considered the impact that treatment for hyperthyroidism might have on cardiovascular risk. It is also unclear whether long-term prognosis differs between Graves' disease and toxic nodular goiter. The aim of this study was to use a very large cohort built on recent data to assess whether improvements in cardiovascular care might have changed the prognosis over time. The study also investigated the impact of different etiologies of hyperthyroidism.METHODS: This was an observational register study for the period 1976-2012, with subjects followed for a median period of 18.4 years. Study patients were Stockholm residents treated for Graves' disease or toxic nodular goiter with either radioactive iodine or surgery (N = 12,239). This group was compared to Stockholm residents treated for nontoxic goiter (N = 3685), with adjustments made for age, sex, comorbidities, and time of treatment. Comparisons were also made to the general population of Stockholm. Outcomes were assessed in terms of all-cause and cardiovascular mortality as well as cardiovascular morbidity.RESULTS: The hazard ratios (HR) for all-cause mortality and for cardiovascular mortality were 1.27 [confidence interval (CI) 1.20-1.35] and 1.29 [CI 1.17-1.42], respectively, for hyperthyroid patients compared to those with nontoxic goiter. For cardiovascular morbidity, the HR was 1.12 [CI 1.06-1.18]. Patients aged ≥45 years who were treated for toxic nodular goiter were generally at greater risk than others, and those included from the year 1990 and onwards were at greater risk than those included earlier. Increased all-cause mortality, as well as cardiovascular mortality and morbidity, were also seen in comparisons with the general population.CONCLUSIONS: This is the first large study to indicate that the long-term risk of death and cardiovascular disease in hyperthyroid subjects is due to the hyperthyroidism itself and not an effect of confounding introduced by its treatment. Much of the excess risk is confined to individuals treated for toxic nodular goiter. Despite advances in cardiovascular care during recent decades, hyperthyroidism is still a diagnosis associated with increased cardiovascular morbidity and mortality.
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| 28. |
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| 29. |
- Hall, Marianne, 1976, et al.
(författare)
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Which are the most important parameters for modelling carbon assimilation in boreal Norway spruce under elevated [CO2] and temperature conditions?
- 2013
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Ingår i: Tree Physiology. - : Oxford University Press (OUP). - 0829-318X .- 1758-4469. ; 33:11, s. 1156-1176
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Tidskriftsartikel (refereegranskat)abstract
- Photosynthesis is highly responsive to environmental and physiological variables, including phenology, foliage nitrogen (N) content, atmospheric CO2 concentration ([CO2]), irradiation (Q), air temperature (T) and vapour pressure deficit (D). Each of these responses is likely to be modified by long-term changes in climatic conditions such as rising air temperature and [CO2]. When modelling photosynthesis under climatic changes, which parameters are then most important to calibrate for future conditions? To assess this, we used measurements of shoot carbon assimilation rates and microclimate conditions collected at Flakaliden, northern Sweden. Twelve 40-year-old Norway spruce trees were enclosed in whole-tree chambers and exposed to elevated [CO2] and elevated air temperature, separately and in combination. The treatments imposed were elevated temperature, +2.8°C in July/August and +5.6°C in December above ambient, and [CO2] (ambient CO2 ∼370μmolmol−1, elevated CO2 ∼700μmolmol−1). The relative importance of parameterization of Q, T and D responses for effects on the photosynthetic rate, expressed on a projected needle area, and the annual shoot carbon uptake was quantified using an empirical shoot photosynthesis model, which was developed and fitted to the measurements. The functional form of the response curves was established using an artificial neural network. The [CO2] treatment increased annual shoot carbon (C) uptake by 50%. Most important was effects on the light response curve, with a 67% increase in light-saturated photosynthetic rate, and a 52% increase in the initial slope of the light response curve. An interactive effect of light saturated photosynthetic rate was found with foliage N status, but no interactive effect for high temperature and high CO2. The air temperature treatment increased the annual shoot C uptake by 44%. The most important parameter was the seasonality, with an elongation of the growing season by almost 4 weeks. The temperature response curve was almost flat over much of the temperature range. A shift in temperature optimum had thus an insignificant effect on modelled annual shoot C uptake. The combined temperature and [CO2] treatment resulted in a 74% increase in annual shoot C uptake compared with ambient conditions, with no clear interactive effects on parameter values.
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| 30. |
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| 31. |
- Hasper, Thomas Berg, et al.
(författare)
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Stomatal CO2 responsiveness and photosynthetic capacity of tropical woody species in relation to taxonomy and functional traits
- 2017
-
Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 184:1, s. 43-57
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 The Author(s)Stomatal CO2 responsiveness and photosynthetic capacity vary greatly among plant species, but the factors controlling these physiological leaf traits are often poorly understood. To explore if these traits are linked to taxonomic group identity and/or to other plant functional traits, we investigated the short-term stomatal CO2 responses and the maximum rates of photosynthetic carboxylation (Vcmax) and electron transport (Jmax) in an evolutionary broad range of tropical woody plant species. The study included 21 species representing four major seed plant taxa: gymnosperms, monocots, rosids and asterids. We found that stomatal closure responses to increased CO2 were stronger in angiosperms than in gymnosperms, and in monocots compared to dicots. Stomatal CO2 responsiveness was not significantly related to any of the other functional traits investigated, while a parameter describing the relationship between photosynthesis and stomatal conductance in combined leaf gas exchange models (g1) was related to leaf area-specific plant hydraulic conductance. For photosynthesis, we found that the interspecific variation in Vcmax and Jmax was related to within leaf nitrogen (N) allocation rather than to area-based total leaf N content. Within-leaf N allocation and water use were strongly co-ordinated (r2 = 0.67), such that species with high fractional N investments into compounds maximizing photosynthetic capacity also had high stomatal conductance. We conclude that while stomatal CO2 responsiveness of tropical woody species seems poorly related to other plant functional traits, photosynthetic capacity is linked to fractional within-leaf N allocation rather than total leaf N content and is closely co-ordinated with leaf water use.
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| 32. |
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| 33. |
- Hasper, Thomas Berg, et al.
(författare)
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Water use by Swedish boreal forests in a changing climate
- 2016
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 30:5, s. 690-699
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Tidskriftsartikel (refereegranskat)abstract
- The rising levels of atmospheric carbon dioxide concentration ([CO2]) and temperature have the potential to substantially affect the terrestrial water and energy balance by altering the stomatal conductance and transpiration of trees. Many models assume decreases in stomatal conductance and plant water use under rising [CO2], which has been used as a plausible explanation for the positive global trend in river run-off over the past century. Plant water use is, however, also affected by changes in temperature, precipitation and land use, and there is yet no consensus about the contribution of different drivers to temporal trends of evapotranspiration (ET) and river run-off. In this study, we assessed water-use responses to climate change by using both long-term monitoring and experimental data in Swedish boreal forests. Historical trends and patterns in ET of large-scale boreal landscapes were determined using climate and run-off data from the past 50 years, while explicit tree water-use responses to elevated [CO2] and/or air temperature were examined in a whole-tree chamber experiment using mature Norway spruce (Picea abies (L.) Karst.) trees. The results demonstrated that ET estimated from water budgets at the catchment scale increased by 18% over the past 50 years while run-off did not significantly change. The increase in ET was related to increasing precipitation and a steady increase in forest standing biomass over time. The whole-tree chamber experiment showed that Norway spruce trees did not save water under elevated [CO2] and that experimentally elevated air temperature did not increase transpiration as decreased stomatal conductance cancelled the effect of higher vapour pressure deficit in warmed air. Our findings have important implications for projections of future water use of European boreal coniferous forests, indicating that changes in precipitation and standing biomass are more important than the effects of elevated [CO2] or temperature on transpiration rates.
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| 34. |
- Hellberg, Victoria, et al.
(författare)
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Cochlear Pharmacokinetics of Cisplatin : An In Vivo Study in the Guinea Pig
- 2013
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Ingår i: The Laryngoscope. - : Wiley. - 0023-852X .- 1531-4995. ; 123:12, s. 3172-3177
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Tidskriftsartikel (refereegranskat)abstract
- Objectives/HypothesisCisplatin produces toxic lesions to outer hair cells (OHCs) in the cochlear base but not in the apex. The objective of this study was to compare the pharmacokinetic profile of cisplatin in scala tympani (ST) perilymph in the cochlear base and apex, respectively. Study DesignIn vivo animal study. MethodsForty-seven guinea pigs were given an intravenous bolus injection of an ototoxic dose of cisplatin. Ten to 240 minutes after cisplatin was given, blood, cerebrospinal fluid (CSF), and ST perilymph were aspirated within the same target time. ST perilymph was aspirated from the basal turn and from the apex of the cochlea by two different sampling techniques. Liquid chromatography with postcolumn derivatization was used for quantitative determination of the parent drug. ResultsTen minutes after administration, the concentration of cisplatin in ST perilymph was 4-fold higher in the basal turn of the cochlea than in the apex. At 30 minutes, the drug concentrations did not differ. At 60 minutes, the level of cisplatin in ST perilymph and blood UF was equivalent. The perilymph-blood ratio increased thereafter with time. ConclusionThe pharmacokinetic findings of an early high concentration of cisplatin in the base of the cochlea and delayed elimination of cisplatin from ST perilymph compared to blood might correlate to the cisplatin-induced loss of OHCs in the base of the cochlea. Level of EvidenceN/A. Laryngoscope, 123:3172-3177, 2013
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| 35. |
- Hellman, Per, et al.
(författare)
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Endokrina sjukdomar
- 2016. - 4
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Ingår i: Kirurgi. - Lund : Studentlitteratur AB. - 9789144099842 ; , s. 521-564
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Bokkapitel (refereegranskat)
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| 36. |
- Holmberg, M., et al.
(författare)
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Treatment outcome 6-10 years after diagnosis of hyperthyroidism in 2916 patients : a longitudinal evaluation of a swedish incidence cohort
- 2018
-
Ingår i: Thyroid. - : Mary Ann Liebert. - 1050-7256 .- 1557-9077. ; :S1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Treatment of Graves’ disease (GD) and toxic nodular goiter (TNG) has the objectives to cure hyperthyroidism, prevent recurrent disease and preserve thyroid function. Treatment efficacies and long-termout comes of antithyroid drugs (ATD), radioactive iodine (RAI) or surgery varies in the literature. We report outcome of treatment, cure rate and risk factors for relapse for GD and TNG in an unselected cohort. A prospective incidence-cohort of de novo diagnosed GD and TNG patients (n = 2916) from 2003-05, were invited to a follow-up 6 - 10 years after diagnosis. Questionnaires were sent to 2430 patients regarding treatments, cure rate, recurrence, quality of life, demographic data, comorbidities and life-style factors. Patients were treated according to clinical routine with ATD, RAI or surgery. Of those included, 1186 (83.3%) had GD and 237 (16.7%) had TNG. In GD patients, 351 (45.3%), 264 (81.5%), and 52 (96.3%) were cured by ATD, RAI or surgery respectively as first line treatment. Of those, 77.0%, 15.4% and 3.8% respectively were without levothyr-oxine supplementation at follow-up at 8 – 0.9 years. Including all treatment modalities, 851 (71.8%) of GD patients were cured within one treatment period. At follow-up, 278 (23%) of GD patients had been operated. In TNG patients, RAI cured 88.6% and surgery 92.9%, whereof 52/154 (33.8%) and 3/15 (20%) had no levothyroxine supplementation post RAI and surgery, respectively.The proportion that did not feel fully recovered at follow-up was 25.3% of GD and 18.1% of the TNG patients. Overall, treatment of hyperthyroidism results in preserved thyroid function only in 35.3% and 44.7% of GD and TNG cases, respectively. As many as 23.4% of the GD patients end up with surgery although only 4.6% choose it from the beginning. Our treatment tradition cures 71.8% of GD patients and 78.1% of TNG patients within one treatment period. The high number of patients who do not feel recovered 6 -10 years after hyperthyroidism in GD and TNG is are minder of the chronic nature of hyperthyroidism.
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| 37. |
- Jocher, Georg, et al.
(författare)
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Impact of Canopy Decoupling and Subcanopy Advection on the Annual Carbon Balance of a Boreal Scots Pine Forest as Derived From Eddy Covariance
- 2018
-
Ingår i: Journal of Geophysical Research: Biogeosciences. - 2169-8953 .- 2169-8961. ; 123:2, s. 303-325
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Tidskriftsartikel (refereegranskat)abstract
- Apparent net uptake of carbon dioxide (CO 2 ) during wintertime by an ∼ 90 year old Scots pine stand in northern Sweden led us to conduct canopy decoupling and subcanopy advection investigations over an entire year. Eddy covariance (EC) measurements ran simultaneously above and within the forest canopy for that purpose. We used the correlation of above- and below-canopy standard deviation of vertical wind speed (σ w ) as decoupling indicator. We identified 0.33 m s -1 and 0.06 m s -1 as site-specific σ w thresholds for above- and below-canopy coupling during nighttime (global radiation < 20 W m -2 ) and 0.23 m s -1 and 0.06 m s -1 as daytime (global radiation > 20 W m -2 ) σ w thresholds. Decoupling occurred in 53% of the annual nighttime and 14% of the annual daytime. The annual net ecosystem exchange (NEE), gross ecosystem exchange (GEE), and ecosystem respiration (R eco ) derived via two-level filtered EC data were -357 g C m -2 , -1,138 g C m -2 , and 781 g C m -2 , respectively. In comparison, both single-level friction velocity (u * ) and quality filtering resulted in ~ 22% higher NEE, mainly caused by ~ 16% lower R eco . GEE remained similar among filtering regimes. Accounting for changes of CO 2 storage across the canopy in the single-level filtered data could only marginally decrease these discrepancies. Consequently, advection appears to be responsible for the major part of this divergence. We conclude that the two-level filter is necessary to adequately address decoupling and subcanopy advection at our site, and we recommend this filter for all forested EC sites.
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| 38. |
- Klemedtsson, Leif, 1953, et al.
(författare)
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Skogaryd – Integration of terrestrial and freshwater greenhouse gas sources and sinks
- 2010
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Ingår i: 1st COST meeting ‘Belowground carbon in Europeanforest’, Birmensdorf, Switzerland, 26–28 January 2010..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Forests play an important role in the global carbon (C) cycle, and management as well as climate can cause major effects on the balance of C between the atmosphere and the plant/soil system. With re-gard to our commitments to the Kyoto and post-Kyoto actions on climate change, we need reliable predictions on how this balance is affected by management and climate. In 2006 the Skogaryd Research Forest was established in the southwest of Sweden (58°23’N, 12°09’E). The overall goal is to quantify net greenhouse gas (GHG) fluxes from drained spruce forest, by determining the individual fluxes and pools of C and nitrogen and elucidating their connection to site fertility, drainage status and abiotic parameters and then use the generated data in GHG models, for model validations and ultimately emissions predictions. During 2006-2009 the research has fo-cused on two sites, mineral and organic, dominated by Norway spruce (Picea abies). Both sites are drained fertile soils but with different land-use history that have affected their physical properties. Measurements includes: net ecosystem exchange of CO2, Shoot photosynthesis and respiration at different locations within the canopy, stem respiration, emissions of N2O and CH4 using manual cham-bers, soil respiration with automatic chambers including a trenching experiment where root-, mycelia-, and heterotrophic respiration are separated, fine root production using minirhizotrons, and mycelia production. The organic site also includes a wood ash experiment. From 2010 the research will be expanded to the whole watershed, from the mire system via streams, riparian zones, forests, to lakes and the subsequent exchange between the atmosphere and surface waters. Different terrestrial and limnic ecosystems will be linked holistically, using site specific tech-niques at different scales, from aircraft (km2) to chambers (m2) to create integrated models that can be used to quantify net GHG flux for management strategies.
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| 39. |
- Lamba, Shubhangi, 1983, et al.
(författare)
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Leaf physiological responses of mature Norway Spruce trees exposed to elevated carbon dioxide and temperature
- 2014
-
Ingår i: EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Leaf photosynthesis, respiration and stomatal conductance exert strong control over the exchange of carbon, water and energy between the terrestrial biosphere and the atmosphere. As such, leaf physiological responses to rising atmospheric CO2 concentration ([CO2]) and temperature have important implications for the global carbon cycle and rate of ongoing global warming, as well as for local and regional hydrology and evaporative cooling. It is therefore critical to improve the understanding of plant physiological responses to elevated [CO2] and temperature, in particular for boreal and tropical ecosystems. In order to do so, we examined physiological responses of mature boreal Norway spruce trees (ca 40-years old) exposed to elevated [CO2] and temperature inside whole-tree chambers at Flakaliden research site, Northern Sweden. The trees were exposed to a factorial combination of two levels of [CO2] (ambient and doubled) and temperature (ambient and +2.8 °C in summer and +5.6 °C in winter). Three replicates in each of the four treatments were used. It was found that photosynthesis was increased considerably in elevated [CO2], but was not affected by the warming treatment. The maximum rate of photosynthetic carboxylation was reduced in the combined elevated [CO2] and elevated temperature treatment, but not in single factor treatments. Elevated [CO2] also strongly increased the base rate of respiration and to a lesser extent reduced the temperature sensitivity (Q10 value) of respiration; responses which may be important for the carbon balance of these trees which have a large proportion of shaded foliage. Stomatal conductance at a given VPD was reduced by elevated temperature treatment, to a degree that mostly offset the higher vapour pressure deficit in warmed air with respect to transpiration. Elevated [CO2] did not affect stomatal conductance, and thus increased the ratio of leaf internal to external [CO2]. These results indicate that the large elevated [CO2]-induced increase in CO2 uptake is partly counteracted by substantial increases in autotrophic respiration in boreal spruce. Furthermore, stomatal results suggest conservative leaf-level water use responses of spruce to rising [CO2] and temperature.
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| 40. |
- Lamba, Shubhangi, 1983, et al.
(författare)
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Norway spruce forest-atmosphere interactions in a changing climate
- 2012
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Ingår i: A challenging future for the Boreal forests – Can all demands be met? A travelling IUFRO workshop in northern Sweden, August 12 – 19, 2012.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Scope: This study deals with the responses of boreal Norway spruce forest ecosystem processes such as photosynthesis and tree-atmosphere carbon dioxide (CO2) exchange with respect to increasing CO2 concentration and temperature., It combines analyses of experimental data from Flakaliden with different modelling approaches. Research Questions: How does elevated CO2 and temperature affect the responses of photosynthesis, respiration and stomatal conductance in Boreal forests? Can shoot level responses of photosynthesis and stomatal conductance be used to predict observed whole tree level responses using the MAESTRA model?
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| 41. |
- Lamba, Shubhangi, et al.
(författare)
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Physiological acclimation dampens initial effects of elevated temperature and atmospheric CO2 concentration in mature boreal Norway spruce
- 2018
-
Ingår i: Plant, Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 41:2, s. 300-313
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Tidskriftsartikel (refereegranskat)abstract
- Physiological processes of terrestrial plants regulate the land-atmosphere exchange of carbon, water, and energy, yet few studies have explored the acclimation responses of mature boreal conifer trees to climate change. Here we explored the acclimation responses of photosynthesis, respiration, and stomatal conductance to elevated temperature and/or CO2 concentration ([CO2]) in a 3-year field experiment with mature boreal Norway spruce. We found that elevated [CO2] decreased photosynthetic carboxylation capacity (-23% at 25 °C) and increased shoot respiration (+64% at 15 °C), while warming had no significant effects. Shoot respiration, but not photosynthetic capacity, exhibited seasonal acclimation. Stomatal conductance at light saturation and a vapour pressure deficit of 1 kPa was unaffected by elevated [CO2] but significantly decreased (-27%) by warming, and the ratio of intercellular to ambient [CO2] was enhanced (+17%) by elevated [CO2] and decreased (-12%) by warming. Many of these responses differ from those typically observed in temperate tree species. Our results show that long-term physiological acclimation dampens the initial stimulation of plant net carbon assimilation to elevated [CO2], and of plant water use to warming. Models that do not account for these responses may thus overestimate the impacts of climate change on future boreal vegetation-atmosphere interactions.
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| 42. |
- Lebreton, Sebastien, et al.
(författare)
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A Drosophila female pheromone elicits species-specific long-range attraction via an olfactory channel with dual specificity for sex and food
- 2017
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mate finding and recognition in animals evolves during niche adaptation and involves social signals and habitat cues. Drosophila melanogaster and related species are known to be attracted to fermenting fruit for feeding and egg-laying, which poses the question of whether species-specific fly odours contribute to long-range premating communication. Results: We have discovered an olfactory channel in D. melanogaster with a dual affinity to sex and food odorants. Female flies release a pheromone, (Z)-4-undecenal (Z4-11Al), that elicits flight attraction in both sexes. Its biosynthetic precursor is the cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene (7,11-HD), which is known to afford reproductive isolation between the sibling species D. melanogaster and D. simulans during courtship. Twin olfactory receptors, Or69aB and Or69aA, are tuned to Z4-11Al and food odorants, respectively. They are co-expressed in the same olfactory sensory neurons, and feed into a neural circuit mediating species-specific, long-range communication; however, the close relative D. simulans, which shares food resources with D. melanogaster, does not respond to Z4-11Al. Conclusion: The Or69aA and Or69aB isoforms have adopted dual olfactory traits. The underlying gene yields a collaboration between natural and sexual selection, which has the potential to drive speciation.
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| 43. |
- Lin, Yan-Shih, et al.
(författare)
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Optimal stomatal behaviour around the world
- 2015
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 5, s. 459-464
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Tidskriftsartikel (refereegranskat)abstract
- Stomatal conductance (gs) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of gs in predictions of global water and carbon cycle changes, a globalscale database and an associated globally applicable model of gs that allow predictions of stomatal behaviour are lacking. Here,we present a database of globally distributed gs obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model1 and the leaf and wood economics spectrum2,3.We also demonstrate a global relationship with climate. These findings provide a robust theoretical framework for understanding and predicting the behaviour of gs across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.
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| 44. |
- Marshall, John, et al.
(författare)
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Radial diffusion, vertical transport, and refixation of labeled bicarbonate in scots pine stems
- 2016
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Ingår i: AGU Fall meeting, 12-16 December 2016, San Francisco, California, USA.. - San Francisco.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The CO2 produced by a respiring stem provides an index of metabolic activity in the stem and a quantitative estimate of an important component of the forest carbon budget. Production of CO2 by a given stem volume is lost by three competing processes. First, some diffuses radially outward through the bark. Second, some is dissolved and vertically transported upward out of the control volume by the xylem stream. Third, some is refixed by photosynthesis under the bark. The relative balance among these pathways was quantified in 17-m Scots pine trees by 13C-bicarbonate labeling of the xylem stream and monitoring of the 13CO2 in the xylem water, along with continuous monitoring of the radial diffusive flux at four canopy heights and in transpiration from leaves. Most of the label diffused out radially, as 13CO2, immediately above the labeling site, over about a week. The pulse was weakly and briefly detected 4 m above that height. Further up the stem it was not detected at all. We detected significant refixation of CO2 in the stems at all heights above 4 m, where the bark becomes papery and thin, but the label was so weak at this height that refixation had little influence on the pulse chase. We conclude that the vertical flux is negligible in Scots pine, but that the refixation flux must be accounted for in estimates of whole-stem CO2 efflux.
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| 45. |
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| 46. |
- Mattsson, Eskil, 1981, et al.
(författare)
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Heterogeneity and assessment uncertainties in forest characteristics and biomass carbon stocks: Important considerations for climate mitigation policies
- 2016
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Ingår i: Land Use Policy. - : Elsevier BV. - 0264-8377 .- 1873-5754. ; 59, s. 84-94
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Tidskriftsartikel (refereegranskat)abstract
- The management of forests to store carbon and mitigate climate change has received significant inter- national attention during the last decade. Using in situ data from a 2008–2009 forest inventory field campaign in Sri Lanka, this study describes the structural characteristics and carbon stocks of six natural forest types. This paper has a dual scope: i) to highlight the variation in carbon stored in aboveground biomass within and between forest types and ii) to determine the implications of the allometric equa- tions chosen to calculate biomass carbon stocks. This study concerns work related to climate change interventions, such as Reducing Emissions from Deforestation and Forest Degradation (REDD+) and other forest-related, performance-based initiatives that require proper monitoring, reporting, and verification of carbon stocks, sinks and emissions. The results revealed that forests are heterogeneous in terms of tree density and height–diameter relationships, both between and within the six forest types investigated. The mean aboveground carbon stock in the different forest types ranged from 22 to 181 Mg C ha−1 , and there were statistically significant differences in the carbon stocks of the six forest types in 7 of 15 cases. The estimated carbon stock depended heavily on the allometric equation used for the calculations, the variables, and its application to the specific life zone. Due to the diversity of forest structures, these results suggest that caution should be taken when applying default values to estimate forest carbon stocks and emission values in reporting and accounting schemes. The results also indicated the need for allometric equations that are context-specific for different forest types. Therefore, new field investigations and mea- surements are needed to determine these specific allometric equations, as well as the potential variation in forest carbon stocks in tropical natural forests.
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| 47. |
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| 48. |
- Meehan, Adrian David, 1973-, et al.
(författare)
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Lithium-Associated Hypercalcemia: Pathophysiology, Prevalence, Management
- 2018
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Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 42:2, s. 415-424
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Tidskriftsartikel (refereegranskat)abstract
- Background Lithium-associated hypercalcemia (LAH) is an ill-defined endocrinopathy. The aim of the present study was to determine the prevalence of hypercalcemia in a cohort of bipolar patients (BP) with and without concomitant lithium treatment and to study surgical outcomes for lithium-associated hyperparathyroidism. Methods Retrospective data, including laboratory results, surgical outcomes and medications, were collected from 313 BP treated with lithium from two psychiatric outpatient units in central Sweden. In addition, data were collected from 148 BP without lithium and a randomly selected control population of 102 individuals. Logistic regression was used to compare odds of hypercalcemia in these respective populations. Results The prevalence of lithium-associated hypercalcemia was 26%. Mild hypercalcemia was detected in 87 out of 563 study participants. The odds of hypercalcemia were significantly higher in BP with lithium treatment compared with BP unexposed to lithium (adjusted OR 13.45; 95% CI 3.09, 58.55; p = 0.001). No significant difference was detected between BP without lithium and control population (adjusted OR 2.40; 95% CI 0.38, 15.41; p = 0.355). Seven BP with lithium underwent surgery where an average of two parathyroid glands was removed. Parathyroid hyperplasia was present in four patients (57%) at the initial operation. One patient had persistent disease after the initial operation, and six patients had recurrent disease at follow-up time which was on average 10 years. Conclusion The high prevalence of LAH justifies the regular monitoring of calcium homeostasis, particularly in high-risk groups. If surgery is necessary, bilateral neck exploration should be considered in patients on chronic lithium treatment. Prospective studies are needed.
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| 49. |
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| 50. |
- Meehan, Adrian D., 1973-, et al.
(författare)
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The prevalence of lithium-associated hyperparathyroidism in a large Swedish population attending psychiatric outpatient units
- 2015
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Ingår i: Journal of Clinical Psychopharmacology. - 0271-0749 .- 1533-712X. ; 35:3, s. 279-285
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This retrospective study determined the prevalence of lithium-associated hyperparathyroidism (LHPT) in 2 geographically defined, equivalent populations in Sweden, with no other selection bias.Methods: The medical journals of all patients receiving lithium treatment were examined specifically regarding their biochemistry: calcium, parathyroid hormone (PTH), creatinine, and vitamin D. The condition LHPT was defined biochemically. All patient data were noted, and the prevalence of the condition could thereby be calculated.Results: A total of 423 patients were included (251 women and 172 men; 3: 2), treated over a mean of 13.5 years (range, 1-46 years), aged 19 to 92. 77 patients (18%) were identified with LHTP whose median serum calcium-was 2.55 mmol/L and PTH was 99 ng/L. A further 21% showed tendencies toward hypercalcemia. Forty-three percent had vitamin D insufficiency. Five patients (approximately 1%) had undergone parathyroidectomy.Conclusion: The prevalence of LHPT is high and often goes undetected. Vitamin D insufficiency is common as is polypharmacy. Surgery, for unclear reasons, has not been performed extensively, possibly because of limited knowledge of the underlying pathophysiology or surgery's significance. We present standard recommendations on patient management and suggest continual, specific follow-up including the monitoring of calcium, PTH, and vitamin D at least annually. Surgery should be considered with intention to improve psychiatric well-being and provide multiorgan protection.
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