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Sökning: WFRF:(Mårtensson Stefan)

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1.
  • Svedhem, Sofia, et al. (författare)
  • Subtle differences in dissociation rates of interactions between destabilized human carbonic anhydrase II mutants and immobilized benzenesulfonamide inhibitors probed by a surface plasmon resonance biosensor
  • 2001
  • Ingår i: Analytical Biochemistry. - : Elsevier BV. - 0003-2697 .- 1096-0309. ; 296:2, s. 188-196
  • Tidskriftsartikel (refereegranskat)abstract
    • The development of commercial biosensors based on surface plasmon resonance has made possible careful characterization of biomolecular interactions. Here, a set of destabilized human carbonic anhydrase II (HCA II) mutants was investigated with respect to their interaction kinetics with two different immobilized benzenesulfonamide inhibitors. Point mutations were located distantly from the active site, and the destabilization energies were up to 23 kJ/mol. The dissociation rate of wild-type HCA II, as determined from the binding to the inhibitor with higher affinity, was 0.019 s−1. For the mutants, dissociation rates were faster (0.022–0.025 s−1), and a correlation between faster dissociation and a high degree of destabilization was observed. We interpreted these results in terms of increased dynamics of the tertiary structures of the mutants. This interpretation was supported by entropy determinations, showing that the entropy of the native structure significantly increased upon destabilization of the protein molecule. Our findings demonstrate the applicability of modern biosensor technology in the study of subtle details in molecular interaction mechanisms, such as the long-range effect of point mutations on interaction kinetics.
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2.
  • Aad, G., et al. (författare)
  • Combination of searches for invisible decays of the Higgs boson using 139 fb−1 of proton-proton collision data at √s=13 TeV collected with the ATLAS experiment
  • 2023
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 842
  • Tidskriftsartikel (refereegranskat)abstract
    • Many extensions of the Standard Model predict the production of dark matter particles at the LHC. Sufficiently light dark matter particles may be produced in decays of the Higgs boson that would appear invisible to the detector. This Letter presents a statistical combination of searches for H→invisible decays where multiple production modes of the Standard Model Higgs boson are considered. These searches are performed with the ATLAS detector using 139 fb−1 of proton–proton collisions at a centre–of–mass energy of   at the LHC. In combination with the results at √s=7TeV and 8TeV, an upper limit on the H→invisible branching ratio of 0.107 (0.077) at the 95% confidence level is observed (expected). These results are also interpreted in the context of models where the 125 GeV Higgs boson acts as a portal to dark matter, and limits are set on the scattering cross-section of weakly interacting massive particles and nucleons.
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3.
  • Aad, G., et al. (författare)
  • Measurement of the CP properties of Higgs boson interactions with τ-leptons with the ATLAS detector
  • 2023
  • Ingår i: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 83:7
  • Tidskriftsartikel (refereegranskat)abstract
    • A study of the charge conjugation and parity (CP) properties of the interaction between the Higgs boson and τ-leptons is presented. The study is based on a measurement of CP-sensitive angular observables defined by the visible decay products of τ-leptons produced in Higgs boson decays. The analysis uses 139 fb−1 of proton–proton collision data recorded at a centre-of-mass energy of √s=13 TeV with the ATLAS detector at the Large Hadron Collider. Contributions from CP-violating interactions between the Higgs boson and τ-leptons are described by a single mixing angle parameter φτ in the generalised Yukawa interaction. Without constraining the H→ττ signal strength to its expected value under the Standard Model hypothesis, the mixing angle φτ is measured to be 9°±16°, with an expected value of 0°±28° at the 68% confidence level. The pure CP-odd hypothesis is disfavoured at a level of 3.4 standard deviations. The results are compatible with the predictions for the Higgs boson in the Standard Model.
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4.
  • Aad, G., et al. (författare)
  • Measurement of the production of a W boson in association with a charmed hadron in pp collisions at √s=13 TeV with the ATLAS detector
  • 2023
  • Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 108:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The production of a W boson in association with a single charm quark is studied using 140  fb−1 of √s=13  TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. The charm quark is tagged by the presence of a charmed hadron reconstructed with a secondary-vertex fit. The W boson is reconstructed from the decay to either an electron or a muon and the missing transverse momentum present in the event. The charmed mesons reconstructed are D+→K−π+π+ and D*+→D0π+→(K−π+)π+ and the charge conjugate decays in the fiducial regions where pT(e,μ)>30  GeV, |η(e,μ)|<2.5, pT(D(*))>8  GeV, and |η(D(*))|<2.2. The integrated and normalized differential cross sections as a function of the pseudorapidity of the lepton from the W boson decay, and of the transverse momentum of the charmed hadron, are extracted from the data using a profile likelihood fit. The measured total fiducial cross sections are Results are compared with the predictions of next-to-leading-order quantum chromodynamics calculations performed using state-of-the-art parton distribution functions. Additionally, the ratio of charm to anticharm production cross sections is studied to probe the quark asymmetry. The ratio is found to be . The ratio and cross-section measurements are consistent with the predictions obtained with parton distribution function sets that have a symmetric sea, indicating that any asymmetry in the Bjorken-x region relevant for this measurement is small.
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5.
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6.
  • Aad, G., et al. (författare)
  • Observation of four-top-quark production in the multilepton final state with the ATLAS detector
  • 2023
  • Ingår i: European Physical Journal C. - : Institute for Ionics. - 1434-6044 .- 1434-6052. ; 83:6
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents the observation of four-top-quark () production in proton-proton collisions at the LHC. The analysis is performed using an integrated luminosity of 140 fb−1 at a centre-of-mass energy of 13 TeV collected using the ATLAS detector. Events containing two leptons with the same electric charge or at least three leptons (electrons or muons) are selected. Event kinematics are used to separate signal from background through a multivariate discriminant, and dedicated control regions are used to constrain the dominant backgrounds. The observed (expected) significance of the measured signal with respect to the standard model (SM) background-only hypothesis is 6.1 (4.3) standard deviations. The production cross section is measured to be fb, consistent with the SM prediction of 12.0±2.4 fb within 1.8 standard deviations. Data are also used to set limits on the three-top-quark production cross section, being an irreducible background not measured previously, and to constrain the top-Higgs Yukawa coupling and effective field theory operator coefficients that affect production.
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7.
  • Aad, G., et al. (författare)
  • Search for supersymmetry in final states with missing transverse momentum and three or more b-jets in 139 fb-1 of proton-proton collisions at √s=13 TeV with the ATLAS detector
  • 2023
  • Ingår i: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 83:7
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for supersymmetry involving the pair production of gluinos decaying via off-shell third-generation squarks into the lightest neutralino () is reported. It exploits LHC proton–proton collision data at a centre-of-mass energy √s=13 TeV with an integrated luminosity of 139 fb−1 collected with the ATLAS detector from 2015 to 2018. The search uses events containing large missing transverse momentum, up to one electron or muon, and several energetic jets, at least three of which must be identified as containing b-hadrons. Both a simple kinematic event selection and an event selection based upon a deep neural-network are used. No significant excess above the predicted background is found. In simplified models involving the pair production of gluinos that decay via off-shell top (bottom) squarks, gluino masses less than 2.44 TeV (2.35 TeV) are excluded at 95% CL for a massless . Limits are also set on the gluino mass in models with variable branching ratios for gluino decays to , and . 
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8.
  • Aad, G., et al. (författare)
  • Search in diphoton and dielectron final states for displaced production of Higgs or Z bosons with the ATLAS detector in √s=13 TeV pp collisions
  • 2023
  • Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 108:1
  • Tidskriftsartikel (refereegranskat)abstract
    • A search is presented for displaced production of Higgs bosons or Z bosons, originating from the decay of a neutral long-lived particle (LLP) and reconstructed in the decay modes H→γγ and Z→ee. The analysis uses the full Run 2 dataset of proton-proton collisions delivered by the LHC at an energy of √s=13  TeV between 2015 and 2018 and recorded by the ATLAS detector, corresponding to an integrated luminosity of 139  fb−1. Exploiting the capabilities of the ATLAS liquid argon calorimeter to precisely measure the arrival times and trajectories of electromagnetic objects, the analysis searches for the signature of pairs of photons or electrons which arise from a common displaced vertex and which arrive after some delay at the calorimeter. The results are interpreted in a gauge-mediated supersymmetry breaking model with pair-produced Higgsinos that decay to LLPs, and each LLP subsequently decays into either a Higgs boson or a Z boson. The final state includes at least two particles that escape direct detection, giving rise to missing transverse momentum. No significant excess is observed above the background expectation. The results are used to set upper limits on the cross section for Higgsino pair production, up to a mass of 369 (704) GeV for decays with 100% branching ratio of to Higgs (Z) bosons for a lifetime of 2 ns. A model-independent limit is also set on the production of pairs of photons or electrons with a significant delay in arrival at the calorimeter.
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9.
  • Ademovski, Seida Erovic, et al. (författare)
  • The effect of periodontal therapy on intra-oral halitosis : a case series
  • 2016
  • Ingår i: Journal of Clinical Periodontology. - : John Wiley & Sons. - 0303-6979 .- 1600-051X. ; 43:5, s. 445-452
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: The aim of this study was to evaluate the effects of non-surgical periodontal therapy on intra-oral halitosis 3 months after therapy.MATERIAL AND METHODS: Sixty-eight adults with intra-oral halitosis were included in a case series. Intra-oral halitosis was evaluated at baseline, and at 3 months after treatment using the organoleptic scores (OLS), Halimeter® , and a gas chromatograph.RESULTS: Significant reductions for OLS (p < 0.01), total sum of volatile sulphur compounds (T-VSC) (p < 0.01) and methyl mercaptan (MM) (p < 0.05) values were found after treatment. Hydrogen sulphide (H2 S) levels were not significantly reduced. The numbers of probing pockets 4 mm, 5 mm and 6 mm were significantly reduced as a result of therapy (p < 0.001). Bleeding on probing (BOP) and plaque indices were also significantly reduced (p < 0.001). For the 34 individuals with successful periodontal treatment (BOP<20% and a ≥50% reduction of total pocket depth) reductions in OLS (p < 0.01) and T-VSC scores (p < 0.01) were found. Eleven individuals were considered effectively treated for intra-oral halitosis presenting with a T-VSC value <160 ppb, a H2 S value <112 ppb and a MM value <26 ppb.CONCLUSION: Non-surgical periodontal therapy resulted in reduction of OLS, MM and T-VSC values 3 months after therapy. Few individuals were considered as effectively treated for intra-oral halitosis.
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10.
  • Backman, Filip, 1991-, et al. (författare)
  • New techniques for jet calibration with the ATLAS detector
  • 2023
  • Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 83:8
  • Tidskriftsartikel (refereegranskat)abstract
    • A determination of the jet energy scale is presented using proton-proton collision data with a centre-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 140 fb(-1) collected using the ATLAS detector at the LHC. Jets are reconstructed using the ATLAS particle-flow method that combines charged-particle tracks and topo-clusters formed from energy deposits in the calorimeter cells. The anti-kt jet algorithm with radius parameter R = 0.4 is used to define the jet. Novel jet energy scale calibration strategies developed for the LHC Run 2 are reported that lay the foundation for the jet calibration in Run 3. Jets are calibrated with a series of simulation-based corrections, including state-of-the-art techniques in jet calibration such as machine learning methods and novel in situ calibrations to achieve better performance than the baseline calibration derived using up to 81 fb(-1) of Run 2 data. The performance of these new techniques is then examined in the in situ measurements by exploiting the transverse momentum balance between a jet and a reference object. The b-quark jet energy scale using particle flow jets is measured for the first time with around 1% precision using gamma+jet events.
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11.
  • Bagonza, Arthur, et al. (författare)
  • Effectiveness of peer-supervision on pediatric fever illness treatment among registered private drug sellers in East-Central Uganda : An interrupted time series analysis
  • 2021
  • Ingår i: Health Science Reports. - : John Wiley & Sons. - 2398-8835. ; 4:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Rationale aims and objectives: Appropriate treatment of pediatric fever in rural areas remains a challenge and maybe partly due to inadequate supervision of licensed drug sellers. This study assessed the effectiveness of peer-supervision among drug sellers on the appropriate treatment of pneumonia symptoms, uncomplicated malaria, and non-bloody diarrhea among children less than 5 years of age in the intervention (Luuka) and comparison (Buyende) districts, in East-Central Uganda.Methods: Data on pneumonia symptoms, uncomplicated malaria, and non-bloody diarrhea among children less than 5 years of age was abstracted from drug shop sick child registers over a 12-month period; 6 months before and 6 months after the introduction of peer-supervision. Interrupted time series were applied to determine the effectiveness of the peer-supervision intervention on the appropriate treatment of pneumonia, uncomplicated malaria, and non-bloody diarrhea among children less than 5 years of age attending drug shops in East Central Uganda.Results: The proportion of children treated appropriately for pneumonia symptoms was 10.84% (P < .05, CI = [1.75, 19.9]) higher, for uncomplicated malaria was 1.46% (P = .79, CI = [-10.43, 13.36]) higher, and for non-bloody diarrhea was 4.00% (P < .05, CI = [-7.95, -0.13]) lower in the intervention district than the comparison district, respectively.Post-intervention trend results showed an increase of 1.21% (P = .008, CI = [0.36, 2.05]) in the proportion appropriately treated for pneumonia symptoms, no difference in appropriate treatment for uncomplicated malaria, and a reduction of 1% (P < .06, CI = [-1.95, 0.02]) in the proportion of children appropriately treated for non-bloody diarrhea, respectively.Conclusions: Peer-supervision increased the proportion of children less than 5 years of age that received appropriate treatment for pneumonia symptoms but not for uncomplicated malaria and non-bloody diarrhea. Implementation of community-level interventions to improve pediatric fever management should consider including peer-supervision among drug sellers.
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12.
  • Bagonza, Arthur, et al. (författare)
  • 'I know those people will be approachable and not mistreat us' : a qualitative study of inspectors and private drug sellers' views on peer supervision in rural Uganda
  • 2020
  • Ingår i: Globalization and Health. - : Springer Nature. - 1744-8603. ; 16:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Peer supervision improves health care delivery by health workers. However, in rural Uganda, self-supervision is what is prescribed for licensed private drug sellers by statutory guidelines. Evidence shows that self-supervision encourages inappropriate treatment of children less than 5 years of age by private drug sellers. This study constructed a model for an appropriate peer supervisor to augment the self-supervision currently practiced by drug sellers at district level in rural Uganda.METHODS: In this qualitative study, six Key informant interviews were held with inspectors while ten focus group discussions were conducted with 130 drug sellers. Data analysis was informed by the Kathy Charmaz constructive approach to grounded theory. Atlas ti.7 software package was used for data management.RESULTS: A model with four dimensions defining an appropriate peer supervisor was developed. The dimensions included; incentives, clearly defined roles, mediation and role model peer supervisor. While all dimensions were regarded as being important, all participants interviewed agreed that incentives for peer supervisors were the most crucial. Overall, an appropriate peer supervisor was described as being exemplary to other drug sellers, operated within a defined framework, well facilitated to do their role and a good go-between drug sellers and government inspectors.CONCLUSION: Four central contributions advance literature by the model developed by our study. First, the model fills a supervision gap for rural private drug sellers. Second, it highlights the need for terms of reference for peer supervisors. Third, it describes who an appropriate peer supervisor should be. Lastly, it elucidates the kind of resources needed for peer supervision.
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13.
  • Bagonza, Arthur, et al. (författare)
  • Peer supervision experiences of drug sellers in a rural district in East-Central Uganda : a qualitative study
  • 2020
  • Ingår i: Malaria Journal. - : Springer Nature. - 1475-2875. ; 19:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Support supervision improves performance outcomes among health workers. However, the national professional guidelines for new licenses and renewal for Class C drug shops in Uganda prescribe self-supervision of licensed private drug sellers. Without support supervision, inappropriate treatment of malaria, pneumonia and diarrhoea among children under 5 years of age continues unabated. This study assessed experiences of drug sellers and peer supervisors at the end of a peer supervision intervention in Luuka District in East Central Uganda. Methods Eight in-depth interviews (IDIs) were held with peer supervisors while five focus group discussions (FGDs) were conducted among registered drug sellers at the end of the peer supervision intervention. The study assessed experiences and challenges of peer supervisors and drug sellers regarding peer supervision. Transcripts were imported into Atlas.ti 7 qualitative data management software where they were analysed using thematic content analysis. Results Initially, peer supervisors were disliked and regarded by drug sellers as another extension of drug inspectors. However, with time a good relationship was established between drug sellers and peer supervisors leading to regular, predictable and supportive peer supervision. This increased confidence of drug sellers in using respiratory timers and rapid diagnostic tests in diagnosing pneumonia symptoms and uncomplicated malaria, respectively, among children under 5 years. There was also an improvement in completing the sick child register which was used for self-assessment by drug sellers. The drug shop association was mentioned as a place where peer supervision should be anchored since it was a one-stop centre for sharing experiences and continuous professional development. Drug sellers proposed including community health workers in monthly drug shop association meetings so that they may also gain from the associated benefits. Untimely completion of the sick child registers by drug sellers and inadequate financial resources were the main peer supervision challenges mentioned. Conclusion Drug sellers benefitted from peer supervision by developing a good relationship with peer supervisors. This relationship guaranteed reliable and predictable supervision ultimately leading to improved treatment practices. There is need to explore the minimum resources needed for peer supervision of drug sellers to further inform practice and policy.
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14.
  • Bagonza, Arthur, et al. (författare)
  • Regulatory inspection of registered private drug shops in East-Central Uganda-what it is versus what it should be : a qualitative study
  • 2020
  • Ingår i: Journal of Pharmaceutical Policy and Practice. - : SPRINGERNATURE. - 2052-3211. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Regulatory inspection of private drug shops in Uganda is a mandate of the Ministry of Health carried out by the National Drug Authority. This study evaluated how this mandate is being carried out at national, district, and drug shop levels. Specifically, perspectives on how the inspection is done, who does it, and challenges faced were sought from inspectors and drug sellers. Methods Six key informant interviews (KIIs) were held with inspectors at the national and district level, while eight focus group discussions (FGDs) were conducted among nursing assistants, and two FGDs were held with nurses. The study appraised current methods of inspecting drug sellers against national professional guidelines for licensing and renewal of class C drug shops in Uganda. Transcripts were managed using Atlas ti version 7 (ATLAS.ti GmbH, Berlin) data management software where the thematic content analysis was done. Results Five themes emerged from the study: authoritarian inspection, delegated inspection, licensing, training, and bribes. Under authoritarian inspection, drug sellers decried the high handedness used by inspectors when found with expired or no license at all. For delegated inspection, drug sellers said that sometimes, inspectors send health assistants and sub-county chiefs for inspection visits. This cadre of people is not recognized by law as inspectors. Inspectors trained drug sellers on how to organize their drug shops better and how to use new technologies such as rapid diagnostic tests (RDTs) in diagnosing malaria. Bribes were talked about mostly by nursing assistants who purported that inspectors were not interested in inspection per se but collecting illicit payments from them. Inspectors said that the facilitation they received from the central government were inadequate for a routine inspection. Conclusion The current method of inspecting drug sellers is harsh and instills fear among drug sellers. There is a need to establish a well-recognized structure of inspection as well as establish channels of dialogue between inspectors and drug sellers if meaningful compliance is to be achieved. The government also needs to enhance both human and financial resources if meaningful inspection of drug sellers is to take place.
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16.
  • Cappel, Ute B, et al. (författare)
  • Electronic structure dynamics in a low bandgap polymer studied by time-resolved photoelectron spectroscopy.
  • 2016
  • Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 18:31, s. 21921-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Means to measure the temporal evolution following a photo-excitation in conjugated polymers are a key for the understanding and optimization of their function in applications such as organic solar cells. In this paper we study the electronic structure dynamics by direct pump-probe measurements of the excited electrons in such materials. Specifically, we carried out a time-resolved photoelectron spectroscopy (TRPES) study of the polymer PCPDTBT by combining an extreme ultraviolet (XUV) high harmonic generation source with a time-of-flight spectrometer. After excitation to either the 1st excited state or to a higher excited state, we follow how the electronic structure develops and relaxes on the electron binding energy scale. Specifically, we follow a less than 50 fs relaxation of the higher exited state and a 10 times slower relaxation of the 1st excited state. We corroborate the results using DFT calculations. Our study demonstrates the power of TRPES for studying photo-excited electron energetics and dynamics of solar cell materials.
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17.
  • Erovic Ademovski, Seida, et al. (författare)
  • The long-term effect of a zinc acetate and chlorhexidine diacetate containing mouth rinse on intra-oral halitosis-A randomized clinical trial.
  • 2017
  • Ingår i: Journal of Clinical Periodontology. - : John Wiley & Sons. - 0303-6979 .- 1600-051X. ; 44:10, s. 1010-1019
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: To evaluate the long-term effects of a zinc acetate and chlorhexidine diacetate mouth rinse (Zn/CHX) on intra-oral halitosis.MATERIALS AND METHODS: Forty-six adults with intra-oral halitosis were randomized into a 6-month, double-blind, placebo-controlled clinical study. The presence of intra-oral halitosis was evaluated at baseline, 3 and 6 months after treatment by assessment of organoleptic score (OLS) and by total volatile sulphur compounds (T-VSC), hydrogen sulphide (H2 S) and methyl mercaptan (MM) concentrations in exhaled air.RESULTS: A Zn/CHX mouth rinse provided significantly better control of intra-oral halitosis than a placebo mouth rinse. At 3 and 6 months, individuals rinsing with the Zn/CHX rinse presented with reductions of the OLS, T-VSC (p < .01, respectively), H2 S (p < .001), and MM (p < .01) in subjects' exhaled air. At 6 months, 68.2% of individuals using the Zn/CHX rinse experienced a 1 or 2 category improvement in OLS compared with 19.1% of placebo-treated subjects. 91% of subjects in the Zn/CHX group were categorized as being effectively treated for intra-oral halitosis (i.e. H2 S < 112 ppb), compared to 43% in the placebo group.CONCLUSION: Zn/CHX mouth rinse provides effective long-term efficacy against intra-oral halitosis, assessed both objectively and subjectively. With regular rinsing, the effect was sustained for 6 months.
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18.
  • Guath, Mona, et al. (författare)
  • Pupil dilation during negative prediction errors is related to brain choline concentration and depressive symptoms in adolescents
  • 2023
  • Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 436
  • Tidskriftsartikel (refereegranskat)abstract
    • Depressive symptoms are associated with altered pupillary responses during learning and reward prediction as well as with changes in neurometabolite levels, including brain concentrations of choline, glutamate and gamma-aminobutyric acid (GABA). However, the full link between depressive symptoms, reward-learning-related pupillary responses and neurometabolites is yet to be established as these constructs have not been assessed in the same individuals. The present pilot study, investigated these relations in a sample of 24 adolescents aged 13 years. Participants completed the Revised Child Anxiety and Depression Scale (RCADS) and underwent a reward learning task while measuring pupil dilation and a single voxel dorsal anterior cingulate cortex (dACC) MEGA-PRESS magnetic resonance spectroscopy scan assessing choline, glutamate and GABA concentrations. Pupil dilation was related to prediction errors (PE) during learning, which was captured by a prediction error-weighted pupil dilation response index (PE-PDR) for each individual. Higher PE-PDR scores, indicating larger pupil dilations to negative prediction errors, were related to lower depressive symptoms and lower dACC choline concentrations. Dorsal ACC choline was positively associated with depressive symptoms, whereas glutamate and GABA were not related to PE-PDR or depressive symptoms. The findings support notions of cholinergic involvement in depressive symptoms and cholinergic influence on reward-related pupillary response, suggesting that pupillary responses to negative prediction errors may hold promise as a biomarker of depressive states.
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19.
  • Kaya, Ibrahim, et al. (författare)
  • On-Tissue Chemical Derivatization of Catecholamines Using 4-(N-Methyl)pyridinium Boronic Acid for ToF-SIMS and LDI-ToF Mass Spectrometry Imaging
  • 2018
  • Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 90:22, s. 13580-13590
  • Tidskriftsartikel (refereegranskat)abstract
    • The analysis of small polar compounds with ToF-SIMS and MALDI-ToF-MS have been generally hindered by low detection sensitivity, poor ionization efficiency, ion suppression, analyte in-source fragmentation, and background spectral interferences from either a MALDI matrix and/or endogenous tissue components. Chemical derivatization has been a well-established strategy for improved mass spectrometric detection of many small molecular weight endogenous compounds in tissues. Here, we present a devised strategy to selectively derivatize and sensitively detect catecholamines with both secondary ion ejection and laser desorption ionization strategies, which are used in many imaging mass spectrometry (IMS) experiments. Chemical derivatization of catecholamines was performed by a reaction with a synthesized permanent pyridinium-cation-containing boronic acid molecule, 4-(N-methyl)pyridinium boronic acid, through boronate ester formation (boronic acid-diol reaction). The derivatization facilitates their sensitive detection with ToF-SIMS and LDI-ToF mass spectrometric techniques. 4-(N-Methyl)pyridinium boronic acid worked as a reactive matrix for catecholamines with LDI and improved the sensitivity of detection for both SIMS and LDI, while the isotopic abundances of the boron atom reflect a unique isotopic pattern for derivatized catecholamines in MS analysis. Finally, the devised strategy was applied, as a proof of concept, for on-tissue chemical derivatization and GCIB-ToF-SIMS (down to 3 μm per pixel spatial resolution) and LDI-ToF mass spectrometry imaging of dopamine, epinephrine, and norepinephrine in porcine adrenal gland tissue sections. MS/MS using collision-induced dissociation (CID)-ToF-ToF-SIMS was subsequently employed on the same tissue sections after SIMS and LDI mass spectrometry imaging experiments, which provided tandem MS information for the validation of the derivatized catecholamines in situ. This methodology can be a powerful approach for the selective and sensitive ionization/detection and spatial localization of diol-containing molecules such as aminols, vic-diols, saccharides, and glycans along with catecholamines in tissue sections with both SIMS and LDI/MALDI-MS techniques. © 2018 American Chemical Society.
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20.
  • Kitutu, Freddy, 1982-, et al. (författare)
  • Can malaria rapid diagnostic tests by drug sellers under feld conditions classify children 5 years old or less with or without Plasmodium falciparum malaria? : Comparison with nested PCR analysis
  • 2018
  • Ingår i: Malaria Journal. - : Springer Science and Business Media LLC. - 1475-2875. ; 17
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Malaria rapid diagnostic tests (RDTs) available as dipsticks or strips, are simple to perform, easily interpretable and do not require electricity nor infrastructural investment. Correct interpretation of and compliance with the malaria RDT results is a challenge to drug sellers. Thus, drug seller interpretation of malaria RDT strips was compared with laboratory scientist re-reading, and PCR analysis of Plasmodium DNA extracted from malaria RDT nitrocellulose strips and Fast Transient Analysis (FTA) cards. Malaria RDT cassettes are also assessed as potential source of Plasmodium DNA.MethodsA total of 212 children aged between 2 and 60 months, 199 of whom had complete records at two study drug shops in south west Uganda participated in the study. Duplicate 5μL samples of capillary blood were picked from the 212 children, dispensed onto the sample well of the CareStartTM Pf-HRP2 RDT cassette and a fast transient analysis (FTA), WhatmanTM 3MM filter paper in parallel. The malaria RDT strip was interpreted by the drug seller within 15 to 20 minutes, visually re-read centrally by laboratory scientist and from it; Plasmodium DNA was recovered and detected by PCR, and compared with FTA recovered P. falciparum DNA PCR detection.ResultsMalaria positive samples were 62/199 (31.2% 95% CI 24.9 - 38.3) by drug seller interpretation of malaria RDT strip, 59/212 (27.8% 95% CI 22.2 – 34.3) by laboratory scientist, 55/212 (25.9% 95% CI 20.0 – 32.6) by RDT nitrocellulose strip PCR and 64/212 (30.2% 95% CI 24.4 – 37.7). The overall agreement between the drug seller interpretation and laboratory scientist re-reading of the malaria RDT strip was 93% with kappa value of 0.8 (95 % CI 0.7, 0.9). The drug seller compliance with the reported malaria RDT results and kappa value were 92.5% and 0.8 (95% CI 0.7, 0.9), respectively. The performance of the three diagnostic strategies compared with FTA PCR as the gold standard had sensitivity between 76.6% and 86.9%, specificity above 90%, positive predictive value ranging from 79% to 89.8% and negative predictive value above 90%.Conclusion:Drug sellers can use of malaria RDTs in field conditions and achieve acceptable accuracy for malaria diagnosis, and they comply with the malaria RDT results. Plasmodium DNA can be recovered from malaria RDT nitrocellulose strips even in the context of drug shops. Future malaria surveillance and diagnostic quality control studies with malaria RDT cassette as a source of Plasmodium DNA are recommended.
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21.
  • Krook, Joakim, 1977- (författare)
  • Concentrate or dilute contaminants? : Strategies for Swedish wood waste
  • 2006
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis aims to assess the environmental consequences of management strategies for wood waste in Sweden. There is a special focus on separation strategies and in what way such measures influence environmental aspects such as the presence of heavy metals in the waste. Actors’ incentives and capacity to influence wood waste management are analysed, emphasising the importance of driving forces such as governmental regulation and market interactions.The results show that, in comparison to present dilution practice, separation of contaminants would lead to decreased heavy metal emissions during combustion of wood waste while still recovering a similar energy yield from the waste. Such measures would also increase possibilities for resource-saving reuse of the generated ash. For most metals, however, long-term pollution concerns related to accumulations in landfills and unintentional co-recycling are difficult to address, regardless of separation strategy. An exception is industrial preservative-treated wood waste that according to regulation is to be separately handled as hazardous, for which separation measures also would address such future concerns. This indicates that governments could play an important role in environmental policy by, for instance, stimulating separate handling of certain discarded products.Actors in the energy sector involved in fuel and heat production have quite restricted capacities for separation of contaminants in wood waste. Instead, achieving substantially less contaminated wood waste seems to require actors in the waste and construction sectors to develop source separation measures. The fact that such measures often involve actors lacking professional standards for waste management constitutes a fundamental obstacle to efficient separation. Perhaps even more hampering is that source separation at present leads to increased waste disposal costs for actors in the construction sector. Such economic outcomes of source separation are unfavourable, since these actors consider wood waste as a disposal problem for which the costs should be minimised. Despite these obstacles, however, the results show that some actors have proved capable of achieving relatively efficient separation.At present, only a minor share of industrial preservative–treated wood waste is separately handled as hazardous. For actors in the energy, waste and construction sectors, the incentives for such measures appear low even though introduced regulations potentially could have created such incentives. It appears as if a lack of steering mechanisms such as communication and supervision have neutralised the inherent pressure from regulation in many cases. Quality requirements, on the other hand, can be concluded to be of outmost importance for motivating separation measures. Unfortunately, market forces encourage actors in the energy sector to practice inconsistent enforcement of quality requirements. As a consequence, actors in the waste and construction sectors do not experience any strong pressure for separation of contaminants from their customers. In fact, such an inconsistent enforcement of quality requirements seems to have counteracted legal pressures for separation, due to present customer-oriented business management.
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22.
  • Kundrat, J., et al. (författare)
  • GNPy : Lessons Learned and Future Plans [Invited]
  • 2022
  • Ingår i: 2022 European Conference on Optical Communication, ECOC 2022. - : Institute of Electrical and Electronics Engineers Inc.. - 9781957171159
  • Konferensbidrag (refereegranskat)abstract
    • We discuss the history, past challenges and future plans of GNPy, an open source project for simulating physical impairments in contemporary DWDM network. The paper describes the unique interaction among network operators, equipment vendors, and standard bodies, as well as challenges in implementing the digital twin of an optical network.
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23.
  • Kyllmar, Katarina, et al. (författare)
  • Small agricultural monitoring catchments in Sweden representing environmental impact
  • 2014
  • Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 198, s. 25-35
  • Tidskriftsartikel (refereegranskat)abstract
    • Nutrient losses to surface waters have been monitored at the small agricultural catchment scale (2-35 km2) for 20 years in Sweden. Eight of the 21 catchments have been more intensively monitored, with flow-proportional stream water sampling, analysis of groundwater quality, yearly crop management surveys and soilcharacterisation.Annual lossesof total nitrogen(N)atcatchmentstreamoutlet vary from6 to 32 kg ha 1, with the largest losses from sandy loam soils in south-west Sweden, where precipitation is high. Losses of total phosphorus (P) vary from 0.1 to 2.0 kg ha 1 year 1 and are largest in catchments with clay soils. Compared with surrounding agricultural areas, crop production is more intensive in most of the monitoring catchments, e.g. the production of annual crops for the market constitutes a larger share of arable land than production of ley in 15 out of 21 monitoring catchments. A more intensive crop production is a consequence of a preference for a high proportion of arable land in the monitoring area which coincides with more productive agricultural areas inthe regions. Knowing how the catchmentsrelate tootheragricultural areasis important when the catchments are used as indicators of agricultural impacts on surface waters. For detection of the success of implemented mitigation measures, small monitoring catchments are suitable since the response on stream water quality is faster than in larger river catchments where the contribution from other sources is larger and retention in streams and lakes occurs to a larger extent. The catchment information also enhances validation of models used for estimating losses of nutrients from other agricultural areas where information on crops, soils and climate exist but data on agricultural management and water quality is scarce.
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24.
  • Levinsson, Henrik, et al. (författare)
  • Course design as a stronger predictor of student evaluation of quality and student engagement than teacher ratings
  • Ingår i: Higher Education. - 1573-174X.
  • Tidskriftsartikel (refereegranskat)abstract
    • Research on Student Evaluation of Teaching (SET) has indicated that course design is at least as important as teachers’ performance for student-rated perceived quality and student engagement. Our data analysis of more than 6000 SETs confirms this. Two hierarchical multiple regression models revealed that course design significantly predicts perceived quality more strongly than teachers, and that course design significantly predicts student engagement independent of teachers. While the variable teachers is a significant predictor of perceived quality, it is not a significant predictor of student engagement. In line with previous research, the results suggest it is important to highlight the vital impact of course design. The results are discussed particularly in relation to improved teaching practice and student learning, but also in terms of how student evaluations of teaching can be used in meaningful ways.
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25.
  • Mårtensson, Björn, et al. (författare)
  • SuxNet – Implementation of Secure Authentication for WLAN
  • 2003
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Wireless network equipment offers great flexibility for mobile as well as stationary computers. Clients are no longer bound by the length of a network cable. Instead wireless connectivity increases the clients’ mobility. This paper describes an implementation for wireless clients to access a wired computer network through an efficient authentication mechanism. The imple-mentation is called SuxNet, and is a contribution to IP-login [8] and Institute of Electrical and Electronics Engineers (IEEE) 802.1x [3]. The paper also explains and evaluates different security concepts such as Wired Equivalent Privacy (WEP) and IEEE 802.1x.
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26.
  • Mårtensson, Carina, et al. (författare)
  • Factors behind change in knowledge after a mass media campaign targeting periodontitis
  • 2006
  • Ingår i: International Journal of Dental Hygiene. - 1601-5029 .- 1601-5037. ; 4:1, s. 8-14
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to investigate changes in knowledge before and after a mass media campaign, in relation to social attributes, care system attributes and oral health aspects. The study was based on a questionnaire in a cohort design, sent out to 900 randomly sampled people aged 50–75 in Sweden. The response rate to the questionnaire before and after the campaign was 70% and 65% respectively. Sixty-four percent answered both questionnaires. Two questions addressed knowledge, while 10 questions aimed to measure social attributes, care system attributes and oral health aspects. Data were analysed for bivariate relations as to change in knowledge and social attributes, care system attributes and oral health aspects. Data were also analysed in multiple regression analysis with knowledge before, knowledge after and knowledge differences as dependent variables. The results showed that there were a number of independent variables with influence on the dependent variables. Of the social attributes, secondary education gave almost 10% (P < 0.001) better knowledge both before and after the campaign. Among care system attributes, high care utilization was related to knowledge both before and after the campaign. The most important factors for knowledge about periodontitis were education, care utilization and perceived importance of oral health. In conclusion, this study demonstrates that mass media might increase knowledge about periodontitis as a health promotion strategy.
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27.
  • Mårtensson, Carina, et al. (författare)
  • Factors behind change in knowledge after a mass media campaign targeting periodontitis
  • 2006
  • Ingår i: International Journal of Dental Hygiene. - : Wiley. - 1601-5029 .- 1601-5037. ; 4:1, s. 8-14
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to investigate changes in knowledge before and after a mass media campaign, in relation to social attributes, care system attributes and oral health aspects. The study was based on a questionnaire in a cohort design, sent out to 900 randomly sampled people aged 50–75 in Sweden. The response rate to the questionnaire before and after the campaign was 70% and 65% respectively. Sixty-four percent answered both questionnaires. Two questions addressed knowledge, while 10 questions aimed to measure social attributes, care system attributes and oral health aspects. Data were analysed for bivariate relations as to change in knowledge and social attributes, care system attributes and oral health aspects. Data were also analysed in multiple regression analysis with knowledge before, knowledge after and knowledge differences as dependent variables. The results showed that there were a number of independent variables with influence on the dependent variables. Of the social attributes, secondary education gave almost 10% (P< 0.001) better knowledge both before and after the campaign. Among care system attributes, high care utilization was related to knowledge both before and after the campaign. The most important factors for knowledge about periodontitis were education, care utilization and perceived importance of oral health. In conclusion, this study demonstrates that mass media might increase knowledge about periodontitis as a health promotion strategy.
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28.
  • Mårtensson, Carina, 1954-, et al. (författare)
  • Knowledge on periodontal disease before and after a mass media campaign
  • 2004
  • Ingår i: Swedish Dental Journal. - 0347-9994. ; 28:4, s. 165-171
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to evaluate if a mass media campaign regarding periodontal disease could increase the knowledge in the general population of diagnoses, symptoms and treatment options of periodontal disease. More specifically, the aim was to investigate the number of correct answers to knowledge questions before and after the campaign. The Swedish Association of Periodontology conducted the campaign through brochures, newspapers, radio and TV. The effect of the campaign was evaluated by a pre- and post campaign questionnaire with a cohort design. From a national population register of 50-75 year olds in Sweden, 900 persons were randomly sampled for the study. A total of 64% of the sample answered both questionnaires. The result of the study showed an improvement among the respondents. There was a significant increase in the number of correct answers regarding diagnoses, symptoms and treatments of periodontitis. In the questionnaire, correct answers regarding "Mobile teeth" increased from 57% to 65% (p=0.003) and "careful dental hygiene" from 65% to 73% (p=0.001). Kappa value's were calculated for consistency in the reply and all kappa values were low especially for the questions "X-ray" (0.36) and "Cleaning between the teeth" (0.38). It was concluded that the campaign probably was successful from a public health knowledge standpoint.
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29.
  • Mårtensson, Carina, et al. (författare)
  • Knowledge on periodontal disease before and after a mass media campaign
  • 2004
  • Ingår i: Swedish Dental Journal. - : Swedish Dental Association. - 0347-9994. ; 28:4, s. 165-171
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to evaluate if a mass media campaign regarding periodontal disease could increase the knowledge in the general population of diagnoses, symptoms and treatment options of periodontal disease. More specifically, the aim was to investigate the number of correct answers to knowledge questions before and after the campaign. The Swedish Association of Periodontology conducted the campaign through brochures, newspapers, radio and TV. The effect of the campaign was evaluated by a pre- and post campaign questionnaire with a cohort design. From a national population register of 50-75 year olds in Sweden, 900 persons were randomly sampled for the study. A total of 64% of the sample answered both questionnaires. The result of the study showed an improvement among the respondents. There was a significant increase in the number of correct answers regarding diagnoses, symptoms and treatments of periodontitis. In the questionnaire, correct answers regarding "Mobile teeth" increased from 57% to 65% (p=0.003) and "careful dental hygiene" from 65% to 73% (p=0.001). Kappa value's were calculated for consistency in the reply and all kappa values were low especially for the questions "X-ray" (0.36) and "Cleaning between the teeth" (0.38). It was concluded that the campaign probably was successful from a public health knowledge standpoint.
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30.
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31.
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32.
  • Mårtensson, H., et al. (författare)
  • Aeroelastic properties of closely spaced modes for a highly loaded transonic fan
  • 2008
  • Konferensbidrag (refereegranskat)abstract
    • In the design of modem compressor blades of wide chord (low aspect ratio) type it is often hard to avoid having modes that are close to each other in frequency. Modes which are closely spaced can interact dynamically. Mistuning and localization of stresses are known problems with this. A potential problem with this is also the possibility of coalescence flutter of the modes. Even if the modes are frequency separated at zero rotational speed, the centrifugal stiffening may cause the modes to attract and even cross (or veer) at some rotational speed. In design, mode separation criteria are sometimes applied in order to minimize the risk of encountering unknown dynamic phenomena. This study is performed to better understand the dynamics of closely spaced modes with respect to risk for coalescence flutter. A reduced order aeroelastic system is then constructed that describes the interaction between the different modes. The aeroelastic couplings are then calculated for the 2 mode system. The method is general in terms of mode shapes and number of interacting modes. A parametrical study is performed in order to study how strongly the modes interact when the frequency separation is decreased and if there is a risk of destructive coalescence flutter. The investigation is performed on a high pressure ratio front stage fan blade. The tendency of the modes to interact depends on the strength of the coupling compared to the strength of the pure structural modes. The tendency towards instability was increased in cases where the stability margin was smaller of the single modes. The results can be considered to support a separation criterion of 2% for the lower. A re-evaluation should be considered if lighter blade material and increased loads are to be used.
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33.
  • Mårtensson, Stefan, et al. (författare)
  • Are avalanche courses the new high-risk sport? : Use of Sensation Seeking Scale in Avalanche Education Highlights the Need for Reassessment of Participants’ True Nature and Suggests that the Test Itself Can Serve as a Learning Tool
  • 2018
  • Konferensbidrag (refereegranskat)abstract
    • In a perfect world, the risk of dying in an avalanche should decrease with knowledge. On the contrary, studies have shown that this risk might increase after an avalanche course. Could it be that par- ticipants from the beginning have an appetite for risks? If so, how high is this preference for risk-taking? Can such knowledge of personal risk preference be used to help the participants understand their own risk-taking? A majority of avalanche accidents are caused by the victim itself, but few studies have inves- tigated the personal disposition of risk-taking. This risk preference can be estimated by measuring sensa- tion seeking. Sensation Seeking Scale (SSS) is a psychometric tool and has been used in studies of high- risk sports such as skiing, parachuting, diving or climbing. During two winters the SSS test was used on Swedish avalanche courses, a total of 333 participants completed the test. The instructors also used the test results in a risk-taking module where participants reflected on their personal risk preferences. Results show that sensation seeking is relatively high among participants. The total average is 21.9 (SD 5.1), which is in line with high-risk sports. Another result is that both participants and instructors experience the test as an important and appreciated module. The conclusions are partly that avalanche courses should be regarded as a high-risk sport because the participants have high-risk preferences, partly that the SSS test itself serves as a learning tool for self-reflection and increased understanding of the participants’ own risk-taking.
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34.
  • Mårtensson, Stefan, et al. (författare)
  • Behovsutredning avseende lavinprognoser för svenska fjällkedjan : Råder det brist på relevant information om när och var det är lavinfarligt i Sverige?
  • 2014
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • There is a shortage in Sweden of relevant information about where and when there is danger of avalanches, and advice on how an individuals or organizations can reduce the risk. In over 70 years, since 1943, different Swedish writers, organizations and government agencies have tried to reduce the number Swedes avalanche fatalities.Our research question can be formulated as follows: Is there in Sweden a real and distinct shortage of relevant information about the avalanche danger for those who are visitors to (users) or are informing about (informers) the Swedish mountains in wintertime? To answer the research question and to describe the lack of information, we have made three different studies; a literature review of Swedish avalanche knowledge, an epidemiological study of Swedish fatalities in avalanches, and a survey of the need for avalanche information.The literature, of about 30 different Swedish books, reports or scientific papers show the following points. A large body of literature, a publication about every two years, is addressing the need for more and better knowledge of avalanches and their impact on individuals and society. The literature describes three traditions; one autonomous in which individuals must fend for himself, an authoritarian where experts make assessments and provide advices, and a descriptive where avalanches are investigated as a phenomenon. The majority of the literature concerns the need to control avalanche danger for various public functions such as roads, railways or economic interests such as ski resorts and tourism businesses.The epidemiological compilation shows about 100 deaths since 1915, i.e. one dead per year on average. The data is somewhat incomplete, but shows a clear trend towards an increasing number of Swedes killed in avalanches. The data shows two periods with an unusually large number of deaths; 1940s, 50s and 60s, with 45 dead and 2000s and 10s with 35 dead. In the last ten years, 25 swedes have died in avalanche accidents.The survey was addressed to both professionals and individuals who reside regularly in the Swedish mountains in the winter. Almost half of respondents, 44 %, have "often" or "always" adapted their behaviour to avalanche danger. A majority, 79%, believe that the current information in Sweden is not consistent or uniform. Almost as many, 78 %, believe that it is difficult to find relevant and updated avalanche danger information. The information that is currently available in Sweden is thus both inaccessible and irrelevant to both professionals and individuals. This distrust leads to that the dubious autonomous knowledge tradition is maintained, in which where everyone tries to be his own avalanche success.The survey also showed that the lack of information in the community is great. Of the professionals a clear majority, 89 %, get regular questions about avalanches and avalanche danger from the public. It should be noted that professional in this survey means anyone with an occupation related to the Swedish Mountains, very few of those actually work with Avalanche issues. This percentage is important to note by two reasons. Firstly, it shows that the public is extensively seeking advice from authority figures and someone who is willing to tell will always fill this lack of information. Secondly the information that was originally autonomous and of uncertain quality and validity from individual professional, now turn into authoritarian information by the public and the media. The risk of false warnings and advices is great since this believed authoritative information does not originate from the quality controlled expert judgments.
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35.
  • Mårtensson, Stefan (författare)
  • Lavinprognoser för svenska fjällen : Utvärdering av ett utvecklingsprojekt vintern 2011 och 2012
  • 2012
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • This report describes an evaluation of a two-year development project with the overall aim to clarify the conditions for establishing a cost-effective, long-term and sustainable avalanche forecasting service for the entire Swedish mountains based on international guidelines and collaborations.The goal of the evaluation was to answer whether and how the development project three main tasks had been completed. The main tasks were: 1. Develop regional avalanche forecasts for the Swedish mountains 2. Develop communication of avalanche forecasts to end-users3. Develop international collaborationsThe project team has used a formative method to conduct the evaluation. This work has included formal evaluation meetings, methodological studies, participation in research conferences, compilation and analysis of existing work, internal and external interviews and comparisons with international research and experience. The report has also been submitted to all organizations in the Swedish Environmental Protection Agency's Mountain Safety Council as a final quality control.The results of the evaluation shows that the development project has had a high task completion. This report presents a quality-assured method to produce credible and clearly communicated avalanche forecasts based on international guidelines and collaborations. The report stresses that it is both possible and relevant with governmental avalanche forecasts for the whole of the Swedish mountains.The evaluation has also found that the quality of avalanche forecasts was high and most likely has reflect the actual avalanche danger during the forecast periods. The report also highlights the great interest from the public, community and media in avalanche safety. Moreover, it is shown that the development project's avalanche forecasts has been costeffective in an international comparison.In the evaluation project, two important conclusions were drawn. First, it is highly relevant and economically viable with avalanche forecasting in order to alert and educate the public in avalanche safety. Second, it must be decided which authority should be responsible, to be able to established a long term avalanche forecasting service.
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36.
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37.
  • Mårtensson, Stefan, et al. (författare)
  • Smartphones as support for out-of-bounds skier decisions : a pilot study of how information about terrain and avalanche danger in a mobile application affects behaviour in off-piste terrain
  • 2014
  • Konferensbidrag (refereegranskat)abstract
    • In a smartphone, a skier can access avalanche information on the go. This paper shows a new app for making decisions, which combines ATES classification with danger ratings and then present- ing this in the form of Avaluator recommendations directly on a GPS-positioned map. We have examined how actual skier behaviour in the terrain is affected by the use of a smartphone as a decision tool. Previ- ous studies on behaviour have mainly focused on surveys or on human factors; it is only now with smartphones with GPS and apps for logging location data that we can study actual movement in the ter- rain. During 10 weeks, 20 skiers used a GPS-based map app in which they answered questions before and after the day's skiing. The app also logged their actual movements during the day. The questions surveyed the subjective approach to risk and skiing. The experiment was conducted in two phases, first a control phase when the app only showed the current avalanche danger and a GPS-map, secondly an effect phase when the app also showed the combination of terrain and avalanche danger using Avaluator colours (Normal Caution, Extra Caution, Not Recommended) projected directly on map as a layer. Our results show that a mobile application can be a successful way to communicate avalanche information in the future. The results also imply it is better to communicate where to ski than to warn where not to ski. At the individual level, we could also see changes in skier's behaviour when they were given access to ava- lanche danger and avalanche terrain in a single map view.
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38.
  • Mårtensson, Stefan, et al. (författare)
  • Snowmobiling in Sweden 2014 : trends, attitudes to risk and knowledge about avalanches
  • 2014
  • Konferensbidrag (refereegranskat)abstract
    • In spring 2014 a web survey aimed towards Swedish snowmobilers were conducted. The aim was to identify riding habits, attitudes to risk, knowledge of avalanches and the use of safety equip- ment. In total 2917 snowmobilers responded. The results provide new and important knowledge about behavior and attitudes to risk and general knowledge about avalanches and avalanche awareness. 34 % of the snowmobilers state that they are sometimes or often in contact with avalanche terrain. Of those, 19 % has been involved in at least on avalanche related incident. In the same group, only 14 % are regularly equipped with avalanche transmitter and probe. Among those who are using avalanche safety equipment, 33 % states that they rarely or never practice to use it.In Sweden the use of snowmobile has greatly increased the past 20 years and so has the popularity re- garding freeriding with snowmobiles in steep terrain. The total number of snowmobiles is now more than 280,000. Between 2005 and 2014, 102 snowmobilers in Sweden where killed in snowmobile related acci- dents in total but very few accidents during this period has officially been avalanche related which is surprisingly. Do Swedish snowmobilers uses the terrain differently than in North America and in Norway where there is much more accidents recorded or is there a difference in their attitudes to risk, or is the relatively few ava- lanche accidents just a coincidence? Is the relatively few accidents connected with the development of stronger and faster snowmobiles? Will Sweden also see a growing number of accidents with more vic- tims? Are there other factors? The final results will be used in the Swedish Mountain Safety Councils efforts to develop future avalanche education programs for snowmobilers and as a way to support research and development in the area.
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39.
  • Mårtensson, Stefan (författare)
  • Svenska offpistskidåkares förutsättningar att hantera lavinfara : Individuella och kontextuella faktorers påverkan på risktagandet
  • 2014
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Every winter die statistically, two to three Swedes in avalanche accidents. Approximately eight out of ten are killed abroad even though only one out of eight Swedes skis outside Sweden. Swedes seem to die in a greater extent than other nationalities abroad. It is not possible to find similar trends in other nationalities mortality in avalanche accidents in skiing abroad.Why do Swedes die in a greater extent than other nationalities when skiing abroad? The overarching question is broken down into two parts. Firstly which are the Swedish off-piste skier’s individual abilities to handle avalanche risk? Secondly how does the domestic knowledge and communication environment look like with respect to avalanche risk?No previous studies have addressed the relationship between individual and contextual factors on management of avalanche risk in a foreign environment. Possible causes of avalanche accidents are described in the literature, with a focus on individual factors.Four studies were conducted to describe the Swedish off-piste skier's individual and contextual factors associated with the handling avalanche risk. The first study was a web-based questionnaire about the experience, knowledge, attitude to risk, and more. The second study was a statistical analysis of the Swedish public avalanche danger ratings during ten years. The third study was a literature review of Swedish avalanche literature from 1943 onwards. The last and fourth study was an online survey with questions about access, quality and relevance, and more with regard to Swedish avalanche communication.The various studies were triangulated with respect to data and methodology in relation to a number of research questions, formulated on the basis of the relationship between perception and preparation on one hand and the experience and trust on the other. The results showed a consistent picture of both individual, and contextual variables. The studies describe Swedish off-piste skiers as experienced, trained, prepared and risk aware. The contextual study showed that the Swedish public avalanche communication is of autonomous nature, hard to find, mostly irrelevant and of uncertain quality and origin.Overall, this work has revealed a possible explanation model that needs to be explored in more detail with respect to how the Swedish off-piste skier's mental models can be described and how Swedish public communication about avalanches should be changed to reduce future mortality abroad among Swedish off-piste skiers.
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40.
  • Mårtensson, Stefan, et al. (författare)
  • Swedish skiers knowledge, experience and attitudes towards off-piste skiing and avalanches
  • 2013
  • Konferensbidrag (refereegranskat)abstract
    • The winter of 2012/2013 was the most accident-prone season in the Swedish avalanche history with a total of seven dead Swedes. In April 2013 the Swedish Mountain Safety Council initiated a web-based survey aimed towards Swedish skiers. The aim was to identify the target group's knowledge, experience and attitudes towards off-piste skiing and avalanches. Respondents were asked to answer a total of 28 questions. 1047 Swedish off-piste skiers answered, and we analysed them in more detail. The Swedish off-piste skier is apparently a seasoned skier who skis a lot every year. About 80 % ski at least two weeks per year and over 90 % have skied for at least 10 years. He or she is well trained and equipped for avalanche accidents. About 90 % possess avalanche equip- ment and about 60 % use it regularly. About 80 % believe they have good avalanche knowledge and 50 % have taken an avalanche course. About 35 % have themselves been caught in an avalanche, and 60 % knows someone who has. Although experience, education and the recent tragic deaths, off- piste and ski touring are increasing, approximately 80 % ski, as much or more, than three years ago. Approximately 50 % are unaffected by the recent accidents and about 75 % are still willing to take risks to go off-piste. The results show no indications of a more restrictive behaviour. The respondents seem often to overestimate their skills when skiing in avalanche terrain. Swedish avalanche education and communication is clearly missing an important piece.
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41.
  • Mårtensson, Stefan (författare)
  • The Ski Resorts Who Cried Wolf : Swedish Historical Public Avalanche Information and the Impact of Different Generations of Danger Scales
  • 2013
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Are Swedes overrepresented in avalanche accidents due to inflation in public avalanche danger? According to preliminary statistics the Swedish skiers are overrepresented as nationality in avalanche accidents in the Alps. A Swedish skier is almost 40 times more likely to die in an avalanche in the Alps than at home in Sweden. What lies behind this phenomenon? Do the Swedes take greater risks than other nationalities? The author presents a hypothesis that the Swedes accident statistics might be traced back to a disturbance in risk understanding due to faulty public avalanche danger rat- ings. In the mid 90's, the first generation avalanche danger scale was introduced and used in Sweden. Unfortunately it contained large errors, and was based solely on weather conditions. Weather as the only criteria led to danger levels rarely below 3 during a winter regardless of actual avalanche danger. This made the Swedish skiers accustomed to a false high avalanche danger for nearly ten years. The author's hypothesis is that this danger inflation has caused that Swedes to have an offset scale per- ception and therefore more often than other nationalities suffer from avalanche accidents. The paper shows how the published avalanche danger ratings at a couple of larger ski resorts in Sweden are correlated to how the danger scale in use is formulated in two generations of scale design. The author presents an explanation of the importance of correct avalanche information to create an accurate un- derstanding of danger in the population. It also presents theories of how collective risk understanding affect risk behaviour.
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42.
  • Mårtensson, Ulrika, et al. (författare)
  • Experiences before and after nasogastric and gastrostomy tube insertion with emphasis on mealtimes: a case study of an adolescent with cerebral palsy
  • 2021
  • Ingår i: International Journal of Qualitative Studies on Health and Well-being. - : Informa UK Limited. - 1748-2623 .- 1748-2631. ; 16:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Adolescents with cerebral palsy may need a feeding tube due to feeding challenges, since nutritional intake and mealtimes may be negatively affected. The purpose of the study was to describe and better understand how one adolescent with cerebral palsy and her parents experienced mealtimes before and after a nasogastric and gastrostomy tube insertion and how the use of these feeding tubes was experienced in daily life. Methods: Individual interviews were performed with one adolescent and each of her parents. In total, six interviews were conducted on two separate occasions. The qualitative approach known as Interpretive Description was used during the analysis. Results: Four thematic patterns were identified within the data: (i) struggling with nutritional intake, (ii) the paradox of using an aid, (iii) being different, and (iv) challenges of public mealtimes. Conclusions: The results showed that four themes influenced daily mealtimes in adolescents with cerebral palsy and a gastrostomy tube. Nutritional intake and mealtimes may be difficult, which is why using a gastrostomy tube can be a relief. However, the gastrostomy tube can also pose a challenge and a paradox. Time of change and acceptance seems necessary in order to meet these challenges.
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43.
  • Mårtensson, Ulrika, et al. (författare)
  • Pain and discomfort in children with gastrostomy tubes – In the context of hematopoietic stem cell transplantation
  • 2023
  • Ingår i: Journal of Pediatric Nursing. - : Elsevier BV. - 0882-5963 .- 1532-8449. ; 70, s. 79-89
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: In children with malignant and severe non-malignant disorders undergoing hematopoietic stem cell transplantation (HSCT), treatment related pain and discomfort are common. Food consumption may become troublesome, making the use of a gastrostomy tube (G-tube) necessary and resulting in complications, why the purpose was to explore pain and discomfort during the transplantation and post-transplantation time. Methods: This was a mixed methods study where data were collected along the child's total health-care process between 2018 and 2021. Questions with fixed answer options were used, simultaneously, semi-structured interviews were performed. In total, sixteen families participated. Descriptive statistics and content analysis were used to describe analysed data. Findings: Intense pain was common during the post-surgery phase, especially in conjunction with G-tube care, which is why the children needed support to manage the situation. After the post-surgery phase when the skin has healed, most of the children experienced minor to no pain or bodily discomfort, why the G-tube became a well-functioning and supportive tool in daily life. Conclusions: This study describes variations in and experiences of pain and bodily discomfort in conjunction with G-tube insertion in a unique sample of children who had undergone HSCT. In conclusion, the children's comfort in daily life after the post-surgery phase seemed to be only marginally affected by G-tube insertion. Children with severe non-malignant disorders seemed to experience a higher frequency and intensity of pain and bodily discomfort due to the G-tube than children with malignant disorders. Practice implications: The paediatric care team need competence in assessing G-tube related pain and awareness that experiences may differ depending on the child's disorder.
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44.
  • Mårtensson, Ulrika, et al. (författare)
  • The five aspect meal model as a conceptual framework for children with a gastrostomy tube in paediatric care
  • 2021
  • Ingår i: Scandinavian Journal of Caring Sciences. - : Wiley. - 0283-9318 .- 1471-6712. ; 35:4, s. 1352-1361
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Cancer treatments may induce side effects and cause eating problems. A gastrostomy tube may be required in order to maintain and optimise the child's nutritional needs. Despite the use of a gastrostomy tube, it is important to maintain a natural and attractive mealtime for the child. The Five Aspect Meal Model is age neutral and originally designed to improve restaurant visits. Its five aspects conceptualise what is necessary to ensure a complete meal experience. To date, there is lack of knowledge to guided model development about mealtimes adapted to children and limited knowledge regarding mealtime experiences for children with a gastrostomy tube. Aim The aim was to investigate whether the Five Aspect Meal Model could be appropriate to be used for children with a gastrostomy tube in caring science and paediatric care. Methods The design followed steps retrieved from Renjith and colleagues. Seven interviews were performed with the Five Aspect Meal Model as a base in the interview guide. The transcripts were analysed by using a qualitative directed content analysis with a deductive approach, which finally passed into a more inductive one. Findings All aspects of the Five Aspect Meal Model were represented in the interviews. There were also experiences related to the gastrostomy tube and the mealtimes that did not fit into any of the five predetermined categories. As a result, the modified version was developed, an adapted prescribing practice model that includes seven aspects, whereof bodily discomfort and time for change and acceptance are specific to children with a gastrostomy tube. Conclusion Based on children and their parent's experiences, the Five Aspect Meal Model has been developed and adapted into a modified version, which includes seven aspects. The modified version seems to be appropriate to use within caring science and paediatric care.
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45.
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46.
  • Sandén, Caroline, et al. (författare)
  • G Protein-Coupled Estrogen Receptor 1 (GPER1)/GPR30 Localizes in the Plasma Membrane and Trafficks Intracellularly on Cytokeratin Intermediate Filaments.
  • 2011
  • Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 79:3, s. 400-410
  • Tidskriftsartikel (refereegranskat)abstract
    • GPR30, or G protein-coupled estrogen receptor 1 (GPER1), was recently introduced as a membrane estrogen receptor and a candidate cancer biomarker and therapeutic target. However, several questions surround the subcellular localization and signaling of this receptor. In native cells, including mouse myoblast C(2)C(12) cells, Madine-Darby canine kidney (MDCK) epithelial cells, and human ductal breast epithelial tumor T47-D cells, G-1, a GPER1 agonist, and 17β-estradiol (E2) stimulated GPER1-dependent cAMP production, a defined plasma membrane (PM) event, and recruitment of β-arrestin2 to the PM. Staining of fixed and live cells showed that GPER1 was localized both in the PM and on intracellular structures. One such intracellular structure was identified as cytokeratin (CK) intermediate filaments, including those composed of CK7 and CK8, but apparently not endoplasmatic reticulum (ER), Golgi, or microtubules. Reciprocal co-immunoprecipitation of GPER1 and CKs confirmed an association of these proteins. Live staining also showed that the PM receptors constitutively internalize apparently to reach CK filaments. Receptor localization was supported using FLAG- and HA-tagged GPER1. We conclude that GPER1-mediated stimulation of cAMP production and β-arrestin2 recruitment occur in the PM. Furthermore, the PM receptors constitutively internalize and localize intracellularly on CK. This is the first observation that a G protein-coupled receptor (GPCR) is capable of associating with intermediate filaments, which may be important for GPER1 regulation in epithelial cells and the relationship of this receptor to cancer.
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47.
  • Senkovskiy, Boris V., et al. (författare)
  • Semiconductor-to-Metal Transition and Quasiparticle Renormalization in Doped Graphene Nanoribbons
  • 2017
  • Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 3:4
  • Tidskriftsartikel (refereegranskat)abstract
    • A semiconductor-to-metal transition in N = 7 armchair graphene nanoribbons causes drastic changes in its electron and phonon system. By using angle-resolved photoemission spectroscopy of lithium-doped graphene nanoribbons, a quasiparticle band gap renormalization from 2.4 to 2.1 eV is observed. Reaching high doping levels (0.05 electrons per atom), it is found that the effective mass of the conduction band carriers increases to a value equal to the free electron mass. This giant increase in the effective mass by doping is a means to enhance the density of states at the Fermi level which can have palpable impact on the transport and optical properties. Electron doping also reduces the Raman intensity by one order of magnitude, and results in relatively small (4 cm−1) hardening of the G phonon and softening of the D phonon. This suggests the importance of both lattice expansion and dynamic effects. The present work highlights that doping of a semiconducting 1D system is strikingly different from its 2D or 3D counterparts and introduces doped graphene nanoribbons as a new tunable quantum material with high potential for basic research and applications.
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48.
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49.
  • Söderström, Patrik, et al. (författare)
  • Snow grooming using machine guidance for piste management processes : Case study: Ormberget ski piste
  • 2013
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The snow is an increasingly precious commodity to the ski industry's production of pistes. To preserve this commodity is the basis for economic production. The wear on the groomed snow consists primarily of two reasons: skiers and melting. A slope that is optimally processed will last longer and require less maintenance. In addition to this obvious that maintenance must be planned based on where wear has taken place there is an additional planning variable, namely time. Timing is of utmost importance when it comes to snow as a material. A process model will be presented covering a systematic approaches how road construction technologies can be adapted to the snow grooming process. The expected results are a process model which can be used in order to optimize the snow grooming management in order to extend the skiing season. There is possibly two ways of doing this. Firstly to optimize the snow mass haul management process during the skiing season. Secondly re-build the different piste off season to create better environmental conditions during season. This study consists of four kinds of data. Laser scanned data for 3D terrain modeling of ski piste (ground) and collected data by snow groomer for 3D terrain modeling of ski piste during the objective period of investigation. The differences between 3D terrain models by laser scanning and snow groomer is representative of snow depth for corresponding day. Furthermore, in order to verify the method, snow depth and snow surface are measured by group of students from Luleå University of Technology.
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50.
  • Wennerstrand, Patricia, et al. (författare)
  • Methotrexate binds to recombinant thiopurine S-methyltransferase and inhibits enzyme activity after high-dose infusions in childhood leukaemia
  • 2013
  • Ingår i: European Journal of Clinical Pharmacology. - : Springer Berlin/Heidelberg. - 0031-6970 .- 1432-1041. ; 69:9, s. 1641-1649
  • Tidskriftsartikel (refereegranskat)abstract
    • PurposeImportant drugs in the treatment of childhood acute lymphoblastic leukaemia (ALL) are 6-mercaptopurine (6-MP) and methotrexate (MTX). Thiopurine methyltransferase (TPMT) is a polymorphic enzyme causing variability in 6-MP response and toxicity. The aim of this study was to investigate the fluctuation in TPMT enzyme activity over time and the effect of high-dose MTX infusions on TPMT enzyme activity and 6-MP metabolites in paediatric ALL patients.MethodsFifty-three children with ALL treated according to the NOPHO-ALL 2000 protocol were included in the study. TPMT enzyme activity was measured at six different times starting from diagnosis until after the end of maintenance treatment. TPMT and 6-MP metabolites were measured before the initiation of high-dose MTX (HD-MTX) infusions and at 66 h post-infusion. The interaction between MTX and TPMT was investigated in vitro using recombinant TPMT protein and a leukaemic cell line.ResultsForty percent of TPMT wild-type individuals had deceptively low TPMT enzyme activity according to genotype at the time of diagnosis. TPMT activity had decreased significantly 66 h after the start of HD-MTX infusions (−9.2 %; p = 0.013). MTX bound to recombinant TPMT protein severely inhibiting TPMT enzyme activity (remaining activity 16 %).ConclusionsOur results show that TPMT genotyping should be performed in children with ALL, since 40 % of the children in our study who carried the wild-type TPMT gene were at risk of initial underdosing of 6-MP in cases where only TPMT enzyme activity was determined. MTX inhibits the TPMT enzyme activity after HD-MTX infusions due to protein binding.
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