| 1. |
- Evangelista, C., et al.
(författare)
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The moment before touchdown: landing manoeuvres of the honeybee Apis mellifera
- 2010
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 213:2, s. 262-270
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Tidskriftsartikel (refereegranskat)abstract
- Although landing is a crucial part of insect flight, it has attracted relatively little study. Here, we investigate, for the first time, the final moments of a honeybee's (Apis mellifera) landing manoeuvre. Using high-speed video recordings, we analyse the behaviour of bees as they approach and land on surfaces of various orientations. The bees enter a stable hover phase, immediately prior to touchdown. We have quantified behaviour during this hover phase and examined whether it changes as the tilt of the landing surface is varied from horizontal (floor), through sloped (uphill) and vertical (wall), to inverted (ceiling). The bees hover at a remarkably constant distance from the surface, irrespective of its tilt. Body inclination increases progressively as the tilt of the surface is increased, and is accompanied by an elevation of the antennae. The tight correlation between the tilt of the surface, and the orientation of the body and the antennae, indicates that the bee's visual system is capable of inferring the tilt of the surface, and pointing the antennae toward it. Touchdown is initiated by extending the appendage closest to the surface, namely, the hind legs when landing on horizontal or sloping surfaces, and the front legs or antennae when landing on vertical surfaces. Touchdown on inverted surfaces is most likely triggered by a mechanosensory signal from the antennae. Evidently, bees use a landing strategy that is flexibly tailored to the varying topography of the terrain.
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| 2. |
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| 3. |
- Ehrencrona, Carolina, 1986, et al.
(författare)
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Do beta-blockers reduce negative intrusive thoughts and anxiety in cancer survivors? – An emulated trial
- 2024
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Ingår i: BMC Cancer. - 1471-2407. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: High rates of negative intrusivethoughts have been reported among cancer patients. Prevalent users of beta-blocker therapy have reported lower levels of cancer related intrusive thoughts than non-user. The aim of this study is to investigate if initiation of beta-blocker therapy reduces the prevalence and severity of intrusive thoughts (co-primary endpoints) and the prevalence of anxiety, depressed mood, and low quality of life (secondary endpoints) in cancer survivors. Methods: Data on patient-reported outcomes from three cohort studies of Swedish patients diagnosed with colon, prostate or rectal cancer were combined with data on beta-blocker prescriptions retrieved from the Swedish Prescribed Drug Register. Two randomized controlled trials were emulated. Trial 1 had follow-up 1year after diagnosis, trial 2 had follow-up 2years after diagnosis, baseline in both trials was 12months before follow-up. Those who initiated beta-blocker therapy between baseline and follow-up was assigned Active group, those who did not was assigned Control group. All endpoints were analysed using Bayesian ordered logistic regression. Results: Trial 1 consisted of Active group, n = 59, and Control group, n = 3936. Trial 2 consisted of Active group, n = 87, and Control group, n = 3132. The majority of participants were men, 83% in trial 1 and 94% in trial 2. The prevalence and severity of intrusive thoughts were lower in the Active group in trial 1, but no significant differences between groups were found in either trial. The prevalence of depressed mood, worse quality of life and periods of anxiety were higher in the Active group in both trials with significant differences for quality of life in trial 1 and anxiety in trial 2. Conclusions: The emulated trials demonstrated no evidence of a protective effect of beta-blocker therapy against intrusive thoughts. The Active group had reduced quality of life and elevated anxiety compared to the Control group. Trial registration: The three cohort studies were registered at isrctn.com/clinicaltrials.gov (ISRCTN06393679, NCT02530593 and NCT01477229).
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| 4. |
- Goodfellow, Bradley W., et al.
(författare)
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Arctic-alpine blockfields in the northern Swedish Scandes : late Quaternary - not Neogene
- 2014
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Ingår i: Earth Surface Dynamics. - : Copernicus GmbH. - 2196-6311 .- 2196-632X. ; 2:2, s. 383-401
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Tidskriftsartikel (refereegranskat)abstract
- Autochthonous blockfield mantles may indicate alpine surfaces that have not been glacially eroded. These surfaces may therefore serve as markers against which to determine Quaternary erosion volumes in adjacent glacially eroded sectors. To explore these potential utilities, chemical weathering features, erosion rates, and regolith residence durations of mountain blockfields are investigated in the northern Swedish Scandes. This is done, firstly, by assessing the intensity of regolith chemical weathering along altitudinal transects descending from three blockfield-mantled summits. Clay / silt ratios, secondary mineral assemblages, and imaging of chemical etching of primary mineral grains in fine matrix are each used for this purpose. Secondly, erosion rates and regolith residence durations of two of the summits are inferred from concentrations of in situ-produced cosmogenic Be-10 and Al-26 in quartz at the blockfield surfaces. An interpretative model is adopted that includes temporal variations in nuclide production rates through surface burial by glacial ice and glacial isostasy-induced elevation changes of the blockfield surfaces. Together, our data indicate that these blockfields are not derived from remnants of intensely weathered Neogene weathering profiles, as is commonly considered. Evidence for this interpretation includes minor chemical weathering in each of the three examined blockfields, despite consistent variability according to slope position. In addition, average erosion rates of similar to 16.2 and similar to 6.7 mm ka(-1), calculated for the two blockfield-mantled summits, are low but of sufficient magnitude to remove present blockfield mantles, of up to a few metres in thickness, within a late Quaternary time frame. Hence, blockfield mantles appear to be replenished by regolith formation through, primarily physical, weathering processes that have operated during the Quaternary. The persistence of autochthonous blockfields over multiple glacial-interglacial cycles confirms their importance as key markers of surfaces that were not glacially eroded through, at least, the late Quaternary. However, presently blockfield-mantled surfaces may potentially be subjected to large spatial variations in erosion rates, and their Neogene regolith mantles may have been comprehensively eroded during the late Pliocene and early Pleistocene. Their role as markers by which to estimate glacial erosion volumes in surrounding landscape elements therefore remains uncertain.
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| 6. |
- Juhlin, Oskar, et al.
(författare)
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Fashionable services for wearables
- 2017
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Ingår i: interactions. - : Association for Computing Machinery (ACM). - 1072-5520 .- 1558-3449. ; 24:3, s. 88-88
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Klintman, Mikael, et al.
(författare)
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Citizen-consumers
- 2016
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Ingår i: Research handbook on climate governance. - : Edward Elgar Publishing. - 9781783470594 ; , s. 309-319
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Bokkapitel (refereegranskat)
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| 8. |
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| 9. |
- Ravn, Hans, et al.
(författare)
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Popliteal Artery Aneurysm with Acute ischemia in 229 Patients : Outcome after Thrombolytic and Surgical Therapy
- 2007
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 33:6, s. 690-695
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to assess the national management and outcome of popliteal artery aneurysm (PAA). Methods: In the Swedish National Registry 717 primary operations for PAA on 571 patients were registered prospectively between 1987 and 2002. 235 patients presented with acute ischemia. Results: Median age was 70 for men and 75 for women. Immediate surgery was performed in 135 legs, including intraoperative thrombolysis in 32 cases (Immediate Surgery Group, ISG). Pre-operative thrombolysis was performed in 100 legs, followed by acute (≤24 hours, 41 legs) or elective (59 legs) surgery (Delayed Surgery Group, DSG). DSG had smaller PAA (27 versus 37 mm, p < 0.0001) and were younger (67 versus 72 years, p < 0.001). Run-off was worse in DSG than in ISG (p < 0.001) and improved in 87% after thrombolysis. Amputation-rate was 27% in the ISG and 7% in the DSG, P < 0.0001. The ISG required fasciotomy in 30% compared to 11% of the DSG, p = 0.0001. Conclusion: Patients in the ISG and DSG differed in their pre-operative characteristics and were selected to the treatment modalities in a complex manner. Preoperative thrombolysis improves run-off.
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| 10. |
- Rodriguez-Vieitez, Elena, et al.
(författare)
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Comparison of Early-Phase C-11-Deuterium-L-Deprenyl and C-11-Pittsburgh Compound B PET for Assessing Brain Perfusion in Alzheimer Disease
- 2016
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 57:7, s. 1071-1077
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Tidskriftsartikel (refereegranskat)abstract
- The PET tracer C-11-deuterium-L-deprenyl (C-11-DED) has been used to visualize activated astrocytes in vivo in patients with Alzheimer disease (AD). In this multitracer PET study, early-phase C-11-DED and C-11-Pittsburgh compound B (C-11-PiB) (eDED and ePiB, respectively) were compared as surrogate markers of brain perfusion, and the extent to which C-11-DED binding is influenced by brain perfusion was investigated. METHODS: C-11-DED, C-11-PiB, and F-18-FDG dynamic PET scans were obtained in age-matched groups comprising AD patients (n = 8), patients with mild cognitive impairment (n = 17), and healthy controls (n = 16). A modified reference Patlak model was used to quantify C-11-DED binding. A simplified reference tissue model was applied to both C-11-DED and C-11-PiB to measure brain perfusion relative to the cerebellar gray matter (R-1) and binding potentials. C-11-PiB retention and F-18-FDG uptake were also quantified as target-to-pons SUV ratios in 12 regions of interest (ROIs). RESULTS: The strongest within-subject correlations with the corresponding R-1 values (R-1,R-DED and R-1,R-PiB, respectively) and with F-18-FDG uptake were obtained when the eDED and ePiB PET data were measured 1-4 min after injection. The optimum eDED/ePiB intervals also showed strong, significant ROI-based intersubject Pearson correlations with R-1,R-DED/R-1,R-PiB and with F-18-FDG uptake, whereas C-11-DED binding was largely independent of brain perfusion, as measured by eDED. Corresponding voxelwise correlations confirmed the ROI-based results. Temporoparietal eDED or ePiB brain perfusion measurements were highly discriminative between patient and control groups, with discriminative ability statistically comparable to that of temporoparietal F-18-FDG glucose metabolism. Hypometabolism extended over wider regions than hypoperfusion in patient groups compared with controls. CONCLUSION: The 1- to 4-min early-frame intervals of C-11-DED or C-11-PiB are suitable surrogate measures for brain perfusion. C-11-DED binding is independent of brain perfusion, and thus C-11-DED PET can provide information on both functional (brain perfusion) and pathologic (astrocytosis) aspects from a single PET scan. In comparison with glucose metabolism, early-phase C-11-DED and C-11-PiB perfusion appear to provide complementary rather than redundant information.
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